geometrical and mechanical properties of the fractures and ... · in this report, the rock...

$: Geometrical and Mechanical Properties of the Fractures and ... · In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the$
Apri l 2014

Working Reports contain information on work in progress

or pending completion.

Charlotta Simel ius

Pöyry Finland Oy

Working Report 2013-32

Geometrical and Mechanical Properties of theFractures and Brittle Deformation Zones Basedon the ONKALO Tunnel Mapping, 4390–4990 m

Tunnel Chainage and the Technical Rooms

GEOMETRICAL AND MECHANICAL PROPERTIES OF THE FRACTURES AND BRITTLE DEFORMATION ZONES, 4390–4990 M TUNNEL CHAINAGE AND THE TECHNICAL ROOMS

ABSTRACT

In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the vicinity of the ONKALO underground research facility at the Olkiluoto site, western Finland. This report is an extension of two previously published reports describing the geometrical and mechanical properties of the fractures and brittle deformation zones based on ONKALO tunnel mapping from tunnel chainages 0–2400 m (Kuula 2010) and 2400–4390 m (Mönkkönen et al. 2012).

This updated report makes use of mapping data from tunnel chainage 4390–4990 m, including the technical rooms located at the -420 m below the sea level. Analysis of the technical rooms is carried out by dividing the premises according to depth into three sections: the demonstration tunnel level, the technical rooms level and the -457 level. The division is executed in order to define the fracture properties in separate areas and to compare the properties with other technical rooms levels. Drillhole data from holes OL-KR1…OL-KR57 is also examined. This report ends the series of three parameterization reports.

The defined rock mechanics parameters of the fractures are based on the rock engineering classification quality index, Q, which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. No new data from laboratory joint shear and normal tests was available at the time of the report.

The fracture wall compressive strength (JCS) data is available from the chainage range 1280–2400 m. New data for fracture wall compressive strength is not available although new Schmidt hammer measurements were performed in order to obtain the ratio of the intact rock mass vs. an intact brittle deformation zone.

Estimation of the mechanical properties of the 23 brittle deformation zones (BDZ) is based on the mapped Q value, which is converted into the GSI value in order to estimate the strength and deformability properties. Components of the mapped Q values are either from the ONKALO or the drill cores depending on the availability of intersections. The location and size of the brittle deformation zones are based on the latest interpretation (Aaltonen et al. expected in 2014). New laboratory data for the intact rock strength of the brittle deformation zones is not available.

Keywords: Nuclear waste disposal, Olkiluoto, ONKALO, rock mechanics, fracture, brittle deformation zones, mechanical properties, Q-mapping.

ONKALON AJOTUNNELIN PAALUVÄLILTÄ 4390–4990 M JA TEKNISISTÄ TILOISTA MÄÄRITETTYJEN RAKOJEN JA RAKOVYÖHYKKEIDEN KALLIOMEKAANISET OMINAISUUDET

TIIVISTELMÄ

Tässä raportissa on esitetty kallion rakojen ja hauraiden deformaatiovyöhykkeiden kalliomekaaniset parametrit ja niiden määritys maanalaisessa tutkimustilassa, ONKALOssa, Olkiluodon alueella Länsi-Suomessa. Tämä raportti on laajennos kahdelle aiemmin julkaistulle raportille, jotka kuvaavat rakojen ja rikkonaisuus-vyöhykkeiden geometrisia ja mekaanisia ominaisuuksia ONKALOssa paaluvälillä 0–2400 m (Kuula 2010) ja 2400–4390 m (Mönkkönen et al. 2012). Lähtöaineistona on käytetty ONKALOn ajotunnelin kalliolaatukartoitusta paaluväliltä 4390–4990 m sekä teknisten tilojen kartoitusaineistoa. Teknisten tilojen käsittely on jaettu syvyyden mukaan kolmeen osaan: demonstraatiotunnelitaso, teknisten tilojen taso ja -457–taso. Jaon perusteella rakojen ominaisuudet on pystytty määrittämään erillisille osuuksille ja ominaisuuksia on pystytty vertaamaan eri tasolla sijaitseviin teknisiin tiloihin. Kaira-reikien OL-KR1…OL-KR57 kartoitusaineistoa on käytetty jossain määrin. Tämä raportti päättää kolmiosaisen parametrisointiraporttien sarjan.

Raportissa esitettyjen kalliorakojen parametrien määritys perustuu pääosin Q-luoki-tuksella määritettyyn kalliolaatuun. Rakopintojen kitkakulma on määritetty luokituksen Jr ja Ja lukujen avulla. Rakopintojen puristuslujuus (JCS) on määritetty paaluväliltä 1280–2400 m. Uutta dataa rakojen laboratoriotestauksista ei ole käytettävissä.

Kahdenkymmenenkolmen (23) hauraan deformaatiovyöhykkeen mekaaniset ominaisuu-det on määritetty niin ikään Q-luokituksen avulla. Q’-luvun avulla on laskettu GSI-luku, josta on määritetty rakovyöhykkeen lujuus- ja muodonmuutosominaisuudet. Rikkonai-suusvyöhykkeiden parametrisoinnin lähtöaineistona on käytetty sekä tunnelikartoitusten että kairareikien dataa. Vyöhykkeiden sijainti ja koko perustuvat uusimpaan tulkintaan (Aaltonen et al. 2014, julkaisematon).

Avainsanat: Ydinjätteen loppusijoitus, Olkiluoto, ONKALO, kalliomekaniikka, rakoilu, hauras deformaatiovyöhyke, rakovyöhyke, rakoilu, mekaaniset ominaisuudet, Q-luokitus.

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TABLE OF CONTENTS

ABSTRACT TIIVISTELMÄ

1 INTRODUCTION .................................................................................................... 3

2 GEOMETRICAL PROPERTIES OF FRACTURES ................................................. 5

2.1 Major fracture sets from tunnel mapping data .................................................. 5

2.1.1 Major fracture sets between chainage 0–2400 m ..................................... 7

2.1.2 Major fracture sets between chainage 2400–4390 m ............................... 8

2.1.3 Major fracture sets between chainage 4390–4990 m ............................. 12

2.1.4 Major fracture sets at the demonstration tunnel level ............................. 14

2.1.5 Major fracture sets at the technical rooms level ...................................... 16

2.1.6 Major fracture sets at -457 level .............................................................. 18

2.1.7 Summary of the distribution of mapped fractures in the ONKALO facility ... ................................................................................................................ 19

2.2 Number of fracture sets, Jn value .................................................................. 21

2.3 Fracture intensity, RQD value ........................................................................ 27

2.4 Fracture length and end type ......................................................................... 32

3 MECHANICAL PROPERTIES OF FRACTURES ................................................. 43

3.1 Fracture surface parameters, Jr and Ja values .............................................. 43

3.2 Fracture filling mineralogy .............................................................................. 49

3.3 Fracture friction angle ..................................................................................... 55

3.4 Fracture undulation ........................................................................................ 58

3.5 Schmidt hammer measurements ................................................................... 61

3.6 Summary of fracture mechanical properties ................................................... 65

4 BRITTLE DEFORMATION ZONES ...................................................................... 67

4.1 Location of brittle deformation zone intersections .......................................... 67

4.2 Estimation of strength and deformability properties ....................................... 69

4.3 Strength of the intact rock .............................................................................. 74

4.4 Strength and deformability properties of brittle deformation zones ................ 78

5 CONCLUSIONS AND RECOMMENDATIONS ..................................................... 85

REFERENCES ............................................................................................................. 89

APPENDICES ............................................................................................................... 91

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1 INTRODUCTION

In order to characterize the Olkiluoto site for the purpose of hosting a radioactive waste repository in western Finland, it is necessary to have an understanding of the rock mechanical behaviour of the rock mass for the prediction of the consequences of various repository design options, including the repository depth and deposition tunnel orientations. If the rock stresses are too high due to the repository depth, rock damage or even spalling are realistic risks in the repository. If repository tunnels intersect or are situated close fracture zones, stronger rock support is required for the tunnels. If there are fractures forming rock blocks, block fallouts can occur on tunnel roof or wall. The extent to which these problems might occur is a function of the stress state, the intact rock properties and fracture/fracture zone properties, and the location and orientation of the excavations.

In this report, the rock mechanic parameters of fractures and brittle deformation zones in the vicinity of the ONKALO area are estimated. This report is an extension of two previously published reports: Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones Based on ONKALO Tunnel Mapping, 0–2400 m Tunnel Chainage (Kuula 2010) and Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones Based on the ONKALO Tunnel Mapping, 2400–4390 m Tunnel Chainage (Mönkkönen et al. 2012), finishing the trilogy of three parameterisation reports. This updated report makes use of new mapping data from tunnel chainage 4390–4990 m which includes the technical rooms in the ONKALO facility.

The term ‘fracture’ refers to a discontinuity in the rock mass which can have been caused by tensile or shear stress. Brittle deformation zones are major zones of fracturing characterized by a large geometrical extent and a much greater width than individual fractures (see e.g. Hudson et al. 2008).

According to Hudson et al. (2008), there are six different methods to estimate the mechanical properties of brittle deformation zones. One of these, which is used in this report, is based on rock mass classification. Other methods involve direct and indirect measurements, analytical formulae based on knowing the properties of individual fracture components, numerical modelling and back analysis. The selection of the rock mass classification method is founded on the good availability of drillcore and tunnel Q-logging data – therefore the method is usable for the entire ONKALO facility.

In this report, the rock mechanics parameters of the fractures are mainly associated with the Rock Tunnelling Quality index, Q (Barton 2002) including RQD value, Jn, Jr and Ja value. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers.

Estimation of the mechanical properties of the brittle deformation zones is based on the mapped Q value which is converted into the GSI value in order to estimate the strength and deformability properties. The defined GSI value is input into numerical simulations.

The determined parameters of this report are used in various rock mechanics analyses: such as key block analyses for rock support design, to estimate the excavation response in the discontinuous rock mass, repository scale thermo-mechanical analyses, and in large scale stress-geology interaction analyses (see e.g. Valli et al. 2011).

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2 GEOMETRICAL PROPERTIES OF FRACTURES

This report makes use of mapping data from the ONKALO access tunnel obtained from a chainage range of 0–4990 m and from the technical rooms, corresponding to an approximate depth range of +3 m to -457 m. The technical rooms are divided into three parts according to depth: the demonstration tunnel level (ca -425 m), the technical rooms level (-437 m) and the -457 level (-457 m). The division is executed in order to define the fracture properties in a delimited area and to compare the properties with another technical rooms levels. The demonstration tunnel level also includes the technical tunnel above the demonstration level at chainage 4366 m and the technical access located below at chainage 4512 m.

Fracture mapping data from the ONKALO area drillholes and tunnel pilot holes is also available but this data does not include fracture length and waviness values. Generally the core logging data is not as reliable as tunnel mapping data and therefore the tunnel mapping data is chosen to the evaluation of the geometrical properties of fractures in this report.

2.1 Major fracture sets from tunnel mapping data

The available data is divided into five sections in order to examine the possible variation of fracture properties and orientations as a function of depth (Figure 2-1). The data obtained from the technical rooms is also split into three parts (Figure 2-2). Each analysed area of the technical rooms level is illustrated in more detail in Appendix 3. The section division of the access tunnel has been performed in a manner that preserves comparability with the previous reports.

The major fracture sets for the first 2400 m of tunnel chainage were interpreted and the related data analysed by Kuula (2010), covering sections 1 and 2 (Figure 2-1). The results concerning major fracture sets from that report are briefly summarized in Chapter 2.1.1.

The chainage range 2400–4390 m is analysed in the previous report (sections 3 and 4, Figure 2-1). The major fracture sets used for that chainage range are from Nordbäck (2010). The distribution of interpreted major fracture sets are presented in a similar manner to the one used in Kuula (2010). Note that the length of section 4 was only 790 m due to data availability at the time of the previous report.

New fracture sets for section 5 are determined in this report. The length of the last chainage range is 600 m.

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Figure 2-1. Analysed tunnel sections.

Figure 2-2. Analysed technical rooms sections.

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2.1.1 Major fracture sets between chainage 0–2400 m

There are four major fracture sets between chainage 0 and 2400 m (Engström & Kemppainen 2008). The sets are interpreted from systematic mapping data and presented in Table 2-1 and in Figure 2-3. Table 2-1. Major fracture sets for chainage 0–2400 m.

Major fracture set Mean dip Mean dip direction

Set 1 08° 065° Set 2 89° 081° Set 3 85° 359°Set 4 32° 135°

The dominant fracture set (Set 1) is almost horizontal, dipping to the NE. The second and the third fracture sets are both nearly vertical, but they differ in dip directions: The second is striking in a N-S orientation when the third set is perpendicular to it. The fourth set is parallel to the foliation, dipping around 32 º to the SE.

Figure 2-3. Fracture pole concentration contours for all mapped tunnel fractures and interpreted set windows (lower hemisphere plot; Engström & Kemppainen 2008).

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The fracture sets presented in Figure 2-3 are compared against the distribution of the fracture sets defined in the round mapping i.e. all of the mapped fractures (systematic mapping) are compared with mapped main fracture directions (round mapping). The previously interpreted fracture set windows have been enlarged to obtain a better adjustment (see Figure 2-4). The Terzaghi correction (Terzaghi 1965) is not used for the fracture data of this report.

Figure 2-4. Fracture pole concentration contours for all fracture sets interpreted in round logging phase and the interpreted set windows (lower hemisphere plot; Kuula H. 2010).


The major fracture sets used in previous report for the 2400–4390 m chainage are from Nordbäck (2010). These sets were originally interpreted from data from chainage range 1980–3116 m. These sets also correspond fairly well with a chainage range of 2400–4390 m.

The fracture sets for chainage 2400–4390 m are named A, B and C, to clearly distinguish them from the numbered fracture sets interpreted for chainage 0–2400 m (sets 1, 2, 3 and 4). The new sets are represented in Table 2-2. The requirement for the use of differing fracture sets is obvious from the difference in fracture distributions between the afore-mentioned chainage ranges (Figure 2-4, Figure 2-5).

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Figure 2-5. The interpreted major fracture sets from Nordbäck (2010) and contours of all of the fractures from chainage 2400–4390 m.

Figure 2-6. The interpreted fracture sets from the round mapping and the set windows from Nordbäck (2010). Data from chainage 2400–4390 m.

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Table 2-2. Major fracture sets for chainage 2400–4390 m.

Major fracture set Mean dip Mean dip direction

Set A 90° 084° Set B 05° 043° Set C 89° 338°

The distribution of the major fracture sets along the length of the tunnel is studied by comparing the fracture sets defined in the round logging phase with the major fracture set windows. Every 5 m section of the access tunnel is analysed and if a logged fracture set in a tunnel section lies within one of the three set windows (Set A, B or C), a 5 m long section is considered as containing that set. If a logged fracture set does not belong to any of the three sets, it is classified as belonging to the group “others”. If a tunnel section does not contain any of the previously mentioned groups, it means that the section does not contain mapped fracture sets. To summarise, a 5 m long tunnel section can therefore contain from none to up to four different group assignments.

From chainage 2400 m to 3240 m the mean poles of the fracture sets from the round mapping phase fall fairly well into the defined prominent fracture sets. After approximately 3200 m, there seems to be an increase in the number of fracture sets not belonging to any of the three sets, A, B or C. This might be due to fact that the prominent fracture sets from Nordbäck (2010) were interpreted from the data from chainage range 1980–3116 m and the data after 3116 m have not had an effect on the interpreted set windows. The vertical set A is most frequently observed in chainage ranges 2480–2760 m and 3780–4050 m. It is also noted that this fracture set becomes more common with increasing chainage values.

The sub-horizontal fracture set B is not commonly observed before chainage 3000 m, but is regularly observed from there on. One notable area of occurrence is between chainages 3120 m and 3320 m, where gently-dipping brittle fracture zones (BFZ) OL-BFZ20a and OL-BFZ20b intersect the tunnel. This is clearly seen in Figure 2-7 and Figure 2-8 and this fracturing is also noted in the DFN model as omitted fracture set DZ-SH (see Section 4.1). Therefore it can be expected that the brittle fracture zones might also have an influence on the dip and dip direction of fracturing in other parts of the tunnel. This influence can, however, be very difficult to notice and is also in most cases insignificant.

The third fracture set, set C, is not common. It is mostly observed in chainage range 2460–2700 m, and after that only occasionally.

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Figure 2-7. Main fracture directions for the ONKALO chainage 2400–3300 m (Mönkkönen et al. 2012).


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The set windows are updated for the last ONKALO access tunnel section and technical rooms levels. The new division is executed on account of different fracture orientations. It includes both the old sets, A, B and C and the new sets B2, C2 and D. The fracture distribution of systematic mapping is presented in Figure 2-10 and for round mapping in Figure 2-11. The new sets are represented in Table 2-3.

The distribution of the major fracture sets along the length of the tunnel is studied by comparing the fracture sets defined in the round logging phase with these new set windows. As earlier, every 5 m section of the access tunnel is analysed and checked to see whether or not it lies within one of the six set windows (Set A, B, B2, C, C2 or D).

In the round logging phase 64 % of the fractures belong to Set A, B2, C or C2. Set A includes 22 %, Set B2 19 %, Set C 7 % and Set C2 15 % of all of the fractures. The vertical fracture set A is commonly observed in the entire access tunnel range 4390–4990 m, except between chainages 4855–4884 m. The amount of Set A fractures is fairly constant with increasing depth. Set B2 fractures become more common from the chainage range 4665–4756 m, where BFZ-300 intersects the access tunnel. Before that the amount of Set B2 fractures is low compared to other fracture sets. Fracture set C is most frequently observed between chainages 4470–4565 m, whereas the rest of the access tunnel has a clear absence of Set C fractures with only occasional occurrences. Set C2 fractures exhibit a fairly constant distribution between fracture sets B2 and C. Nevertheless, Set C2 fractures are absent between chainage range 4470–4532 m.

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Figure 2-10. The interpreted major fracture sets and contours of all of the fractures from chainage 4390–4990 m.

Figure 2-11. The interpreted fracture sets from the round mapping and the set windows of chainage 4390–4990 m.

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Table 2-3. Major fracture sets for chainage 4390–4990 m.

Major fracture set Mean dip Mean dip direction Set A 89° 264°

Set B2 25° 342° Set C 90° 338°

Set C2 61° 335°

2.1.4 Major fracture sets at the demonstration tunnel level

The fracture distribution of the demonstration tunnel level differs slightly from two other technical rooms levels: it has a new set of south dipping fractures, Set D, which is observed only at the demonstration tunnel level. Other fracture sets at this level are Set A and Set C2. The set dip and dip direction statistics are presented in Table 2-4.

43 % of the fractures obtained from the systematic mapping phase lies within these set windows. The distribution between the sets is equal. The distribution of all mapped fractures is depicted in Figure 2-12.

Round mapping data is only available for demonstration tunnel 2 near the access tunnel and for the parallel tunnel, demonstration tunnel 1. Demonstration tunnel fractures fall well into Set A (29 %) and Set D (25 %), but the amount of NW dipping set C2 fractures is low, only 4 % of the fractures. The distribution of the fractures from the round mapping phase is illustrated in Figure 2-13.

The distribution of the fractures is compared with the adjacent demonstration tunnels 1 and 2. In round mapping phase the fracture set A is observed in both demonstration tunnel 1 and 2 where the Set A fractures become more frequent with increasing chainage values. In demonstration tunnel 2 there is a notable concentration of Set A fractures in chainage 56.8–59.6 m due to an intersection with BFZ-45. Demonstration tunnel 2 also exhibits two peaks in the amount of set A fractures at chainages 48.3 m and 78–81.2 m. Demonstration tunnel 1 has a lower amount of Set A fractures in comparison with demonstration tunnel 2. Set A fractures are only observed after 30 m.

Fractures falling into Set C2 are rare in both demonstration tunnels. Set D fractures are more common with increasing chainage values and a significant amount of them occur between chainage ranges 59.6–75 m in demonstration tunnel 2 and 38–44.9 m in demonstration tunnel 1 due to BFZ-297.

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Figure 2-12. The interpreted major fracture sets and contours of all of the fractures from the demonstration tunnel level.

Figure 2-13. The interpreted major fracture sets and set windows from round mapping of demonstration tunnels 1 and 2.

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Table 2-4. Major fracture sets for the demonstration tunnel level.


Set C2 60° 335° Set D 52° 181°

2.1.5 Major fracture sets at the technical rooms level

The fractures at the technical rooms level fall quite well into fracture sets A, B2 and C. In the systematic mapping phase they contain altogether half of the fractures. Set A contains 18 % of the fractures, set B2 a fourth of them and set C 8 %. In the round mapping phase the distribution of the fractures is very similar to the systematically mapped fracture distribution. Distributions of systematic and round mapping phase poles are presented in Figure 2-14 and Figure 2-15 and the set dip and dip direction statistics in Table 2-5.

This chapter focuses on comparing the fracture distribution of parallel tunnels ONK-TT-4642 and ONK-TYT-4665-22, perpendicular tech parking hall and oblique tunnel ONK-TT-4665. The selected sections are illustrated in Figure A3-2. The amount of mapping data from each location is adequate for comparison. The distribution of the fractures into their respective sets has been performed based on the round mapping data available from each location.

Set B2 is the most prominent fracture set in the tech parking hall and is only absent from the last fifth of the tunnel length. There is a significant concentration of subhorizontal B2 fractures at chainage 59 m. Set A and C fractures are equally prevalent. Set A is more common in the western section of the parking hall whilst the distribution of Set C fractures remains constant.

Approximately 40 % of the fractures of the tech tunnel in chainage 4642 m fall into sets A, B2 and C. In contrast to the tech parking hall, set B2 fractures are absent in ONK-TT-4642. Set A fractures become more common northwards where the tunnel meets the western part of the parking hall and are significantly concentrated in this area as well as in the western part of the parking hall. Occurrence of Set C fractures is uniform but negligible.

ONK-TYT-4665 is a tech access tunnel to the parking hall and it is parallel to tech tunnel in chainage 4642 m. Set A fractures occur uniformly. Set B2 fractures are frequently observed in low chainage values but are not present near the parking hall. Set C is uncommon.

The tech tunnel at chainage 4665 m connects the ONKALO access tunnel to the eastern part of the parking hall. Fractures fall better into fracture sets than in the tech tunnel ONK-TT-4642 on the other side. Set A fractures are found constantly through the tunnel. Set B2 fractures are also common, but their amount decreases in the vicinity of the parking hall. A clear increase in the amount of Set B2 fractures is also observed between chainages 23–32 m. The third fracture set, Set C, is uncommon.

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Figure 2-14. The interpreted major fracture sets and contours of all of the fractures from the technical rooms level.

Figure 2-15. The interpreted major fracture sets and set windows from round mapping of the technical rooms level.

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Table 2-5. Major fracture sets for the technical rooms level.


Set B2 26° 346° Set C 88° 338°

2.1.6 Major fracture sets at -457 level

The distribution of fractures is distinct at -457 level which is a result of the low amount of mapped fractures and the small area (Figure 2-16 and Figure 2-17). The most notable fracture set is set B2, which includes over a third of the fractures. Set A is also common; it contains approximately a fifth of all of the mapped fractures. The sets are presented in Table 2-6.

A detailed comparison of the tech tunnel at chainage 4696 m and the perpendicular tech tunnel at chainage 4970 m reveals the following: Set A and B2 fractures are found in ONK-TT-4696, whereas only set A fractures are evident in the perpendicular ONK-TT-4793 tech tunnel. The amount of set A fractures in ONK-TT-4793 increases regularly towards the east end of ONK-TT-4696. More detailed comparison is not possible due to scarce data from the area.

Figure 2-16. The interpreted major fracture sets and contours of all of the fractures from -457 level.

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Figure 2-17. The interpreted major fracture sets and set windows from round mapping of -457 level.

Table 2-6. Major fracture sets for -457 level.


Set B2 28° 338°

2.1.7 Summary of the distribution of mapped fractures in the ONKALO facility

Fracture distribution between chainage range 0–4390 m is fairly similar. Horizontal and steeply east or west dipping fractures are most common. In addition, the chainage range includes steeply northwest dipping fractures, which become more common with increasing depth.

After chainage 4390 m, fracture distribution begins to change and sub-horizontally to northwest dipping fractures become more common. The fracture distribution of the technical rooms levels resembles chainage range 4390–4990 m although the main fracture set at the demonstration tunnel level is comprised of south dipping fractures. Fractures falling into this main fracture set are not noticeably observed elsewhere in the ONKALO facility.

The fracture distribution at different depth levels indicates clear variation of distribution by depth and for this reason it is not sensible to use the same fracture sets for the entire length of the ONKALO tunnel, from chainages 0–4990 m. An illustration of diverging fracture distribution at different depth levels is presented in Figure 2-18.

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Fracture sets identified using visual methods were compared to the field observation results obtained by Posiva's geologists. Field observation results revealed three main fracture sets in the ONKALO access tunnel: steeply east or west dipping fractures, steeply north or south dipping fractures and subhorizontally southeast dipping fractures. The subhorizontally southeast dipping fractures are parallel to the mean orientation of foliation. In addition, subhorizontal fractures that dip to the north-northwest are observed at the level of the technical rooms and fractures that dip to the south only at the level of the demonstration tunnels. Steeply east or west dipping fractures occur in the whole ONKALO tunnel as well steeply north or south dipping fractures, even if their amount is lesser. These observations are in agreement with analysis of fracture orientation except for subhorizontal fractures dipping to the southeast which are only found in the first section of the access tunnel.

Figure 2-18. Stereographic projections of all mapped fractures in different depth levels in the ONKALO facility.

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2.2 Number of fracture sets, Jn value

The Jn value in the Q system is based on the number of fracture sets, where a set is defined as sub-parallel fractures occurring systematically with a characteristic spacing (mean value); ‘random’ fractures are fractures that do not occur in this systematic manner. In terms of block fallout, the minimum number of faces that a block can have is four (a tetrahedral block); the tunnel periphery can form one face, so that a minimum of three fracture sets is then required for a rock block to be formed, indicated by the red lines in Figure 2-19 to Figure 2-26. Foliation can, however, also be included in the calculation of Jn-as one set. In this case Jn is four, which is illustrated with a dashed red line. Figure 2-27 shows visually the distribution of the median joint set number values in the ONKALO access tunnel.

Over the first 300 m of the access tunnel, the Jn median value is 6 (representing two joint sets plus a random set), which means that systematic or occasional rock blocks can be formed. From chainage 300 m to approximately 1200 m, the Jn median value is 3 and after chainage 1200 m, the Jn median drops to 1, although there are isolated instances of Jn=6 beyond 1060 m at 2475 m and around 3300 m. In either case, rock blocks cannot be formed, although it is potentially possible for adversely orientated and weakly bonded foliation to act as one or two additional block faces (Kuula 2010; Mönkkönen et al. 2012).

The Jn value drops from 4 to 2 at the boundary of section 4 and 5. In the last 597 m, the Jn median value is 2 and it is structurally of the same kind as in section 4. Around a chainage range of 4390–4990 m there is an isolated instance of Jn 3 from chainage 4830 m to 4940 m. Between chainages 4390–4990 m the risk of block fallout is low as well as in the previous sections except for the first 1200 meters.

The demonstration tunnel level (-420 m), resembles access tunnel section 5. BFZ-297 intersects demonstration tunnel 2 in round ONK-TDT-4399-30-60 which causes a high Jn peak. This intersection combined with a Jn value of 6 is the area of highest risk at the demonstration tunnel level. Compared with the technical rooms underneath and the -457 levels and their Jn values, the demonstration tunnel level is not as uniform due to its relatively high standard deviation of 1.30. The standard deviation at the level of the technical rooms is 1.06 and at -457 level 0.79.

The technical rooms level has higher Jn mean and median values compared to the demonstration tunnel level, but it does not include high Jn peaks. Tech access tunnel ONK-TYT-4665-22 and adjacent shaft drift KPE1-4665-51 have the lowest values with a median Jn of 1. In other parts the median Jn is 3.

Average, median and maximum Jn values decrease from the technical rooms level to the -457 level underneath. This level is fairly uniform without any isolated Jn-values. Jn-values vary between 1 and 3 and hence -457 level has the lowest risk of block fallout in the entire ONKALO facility.

Table 2-7 presents the statistics of the Jn value for the different tunnel sections. Note that the analysis includes all of the data, i.e. brittle fracturing zone intersections have not been filtered out. Figure 2-28 illustrates the basic statistics of the Jn value at different depth levels.

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Figure 2-19. A histogram of logged Jn values in the ONKALO tunnel between chainage 0–1200 m. Block fall-out due to fractures can only occur when at least two fracture sets are present. Red lines illustrate the risk of block fallout.


0

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3 96 200 326 425 530 630 730 840 945 1055 1165

Jn v

alue

Onkalo chainage

Jn = 9, three joint setsJn = 6, two joint sets + randomJn = 4, two joint setJn = 2, one joint setJn = 0.5‐1, massive; no or few joints

red solid line = possible block falloutred dashed line = possible block fallout; foliation included

0

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1200 1305 1410 1515 1625 1725 1825 1930 2035 2135 2230 2330

Jn v

alu

e

Onkalo chainage



23



0

1

2

3

4

5

6

7

8

9

10

11

12

2400 2500 2610 2720 2840 2945 3045 3150 3255 3355 3460 3560


Jn v

alue

Onkalo chainage


0

1

2

3

4

5

6

7

8

9

10

11

12

3600 3700 3810 3910 4015 4120 4220 4315

Jn v

alue

Onkalo chainage



24


Figure 2-24. A histogram of logged Jn values at the ONKALO demonstration tunnel level. Block fall-out due to fractures can only occur when at least two fracture sets are present. Red lines illustrate the risk of block fallout.

0

1

2

3

4

5

6

7

8

9

10

11

12

4395 4430 4470 4520 4580 4630 4680 4730 4780 4830 4880 4930 4980

Onkalo chainage

Jn v

alue



0

1

2

3

4

5

6

7

8

9

10

11

12

ON

K-T

DT

-439

9-44

-5O

NK

-TD

T-4

39

9-44

-30

ON

K-T

DT

-43

99-

44-3

5O

NK

-TD

T-4

39

9-44

-20

ON

K-T

DT

-43

99-

44-2

5O

NK

-TD

T-4

39

9-44

-40

ON

K-T

DT

-43

99-

44-4

5O

NK

-TD

T-4

39

9-44

-10

ON

K-T

DT

-43

99-

44-1

5O

NK

-TD

T-4

39

9-3

0-1

00O

NK

-TD

T-4

39

9-30

-10

ON

K-T

DT

-43

99-

30-1

5O

NK

-TD

T-4

39

9-30

-20

ON

K-T

DT

-43

99-

30-2

5O

NK

-TD

T-4

39

9-30

-30

ON

K-T

DT

-43

99-

30-3

5O

NK

-TD

T-4

39

9-30

-40

ON

K-T

DT

-43

99-

30-4

5O

NK

-TD

T-4

399-

30-4

ON

K-T

DT

-43

99-

30-5

0O

NK

-TD

T-4

39

9-30

-55

ON

K-T

DT

-43

99-

30-6

0O

NK

-TD

T-4

39

9-30

-65

ON

K-T

DT

-43

99-

30-7

0O

NK

-TD

T-4

39

9-30

-75

ON

K-T

DT

-43

99-

30-8

0O

NK

-TD

T-4

39

9-30

-85

ON

K-T

DT

-43

99-

30-9

0O

NK

-TD

T-4

39

9-30

-95

ON

K-T

T-4

366

-0O

NK

-TT

-43

66-1

5O

NK

-TT

-43

99-0

ON

K-T

T-4

399

-40

ON

K-T

T-4

399

-50

ON

K-T

T-4

399

-60

ON

K-T

T-4

399

-70

ON

K-T

T-4

399

-80

ON

K-T

YT

-439

9-2

1-24

ON

K-T

YT

-439

9-2

1-30

ON

K-T

YT

-439

9-2

1-35

ON

K-T

YT

-439

9-2

1-40

ON

K-T

YT

-439

9-2

1-46

.4O

NK

-TY

T-4

512

-30

ON

K-T

YT

-451

2-0

ON

K-T

YT

-451

2-1

0O

NK

-TY

T-4

512

-20

ON

K-M

KU

-44

02-0

Jn v

alue

Jn = 9, three joint setsJn = 6, two joint sets + randomJn = 4, two joint setJn = 2, one joint setJn = 0.5-1, massive; no or few joints


25

Figure 2-25. A histogram of logged Jn values at the ONKALO technical rooms level. Block fall-out due to fractures can only occur when at least two fracture sets are present. Red lines illustrate the risk of block fallout.

Figure 2-26. A histogram of logged Jn values at the ONKALO -457 level. Block fall-out due to fractures can only occur when at least two fracture sets are present. Red lines illustrate the risk of block fallout.

0

1

2

3

4

5

6

7

8

9

10

11

12

ON

K-T

PH

-466

5-1

54-0

ON

K-T

PH

-466

5-1

54-1

0O

NK

-TP

H-4

665-

154

-20

ON

K-T

PH

-466

5-1

54-3

0O

NK

-TP

H-4

665-

154

-40

ON

K-T

PH

-466

5-1

54-5

0O

NK

-TP

H-4

665-

154

-60

ON

K-T

PH

-466

5-1

54-7

0O

NK

-TP

H-4

665-

154

-80

ON

K-T

PH

-466

5-1

54-9

0O

NK

-TP

H-4

665-

154-

100

ON

K-T

PH

-466

5-15

4-11

0O

NK

-TP

H-4

665-

154-

120

ON

K-T

PH

-466

5-15

4-12

8O

NK

-TT

-464

2-0

ON

K-T

T-4

642

-20

ON

K-T

T-4

642

-30

ON

K-T

T-4

642

-40

ON

K-T

T-4

642

-50

ON

K-T

T-4

642

-60

ON

K-T

T-4

642

-70

ON

K-T

T-4

665-

0O

NK

-TT

-46

65-1

0O

NK

-TT

-46

65-2

0O

NK

-TT

-46

65-3

0O

NK

-TT

-46

65-4

0O

NK

-TT

-46

65-6

0O

NK

-TT

-466

5-64

-flo

orO

NK

-TT

-46

65-7

0O

NK

-TT

-46

65-8

0O

NK

-TT

-46

65-9

0O

NK

-TT

-466

5-10

0O

NK

-TT

-466

5-11

0O

NK

-TT

-466

5-11

0-flo

orO

NK

-TT

-466

5-12

0O

NK

-TT

-466

5-13

0O

NK

-TT

-466

5-14

0O

NK

-TT

-466

5-14

7O

NK

-TT

-466

5-16

0O

NK

-TT

-466

5-17

0O

NK

-TT

-466

5-18

0O

NK

-TY

T-4

665-

22-0

ON

K-T

YT

-466

5-2

2-10

ON

K-T

YT

-466

5-2

2-20

ON

K-T

YT

-466

5-2

2-30

ON

K-T

YT

-466

5-2

2-40

ON

K-T

YT

-466

5-2

2-50

ON

K-T

YT

-466

5-2

2-60

ON

K-T

YT

-466

5-2

2-70

ON

K-T

YT

-466

5-2

2-78

ON

K-T

YT

-466

5-22

-24

-2O

NK

-TY

T-4

665-

22-2

4-1

0O

NK

-TY

T-4

665-

124-

0O

NK

-TY

T-4

665-

124-

10O

NK

-TY

T-4

665-

124

-10-

…O

NK

-TY

T-4

665-

124-

20O

NK

-TY

T-4

665-

124-

20-f

loor

ON

K-T

YT

-466

5-12

4-30

ON

K-T

YT

-466

5-12

4-30

-flo

orO

NK

-TY

T-4

665-

124-

40-f

loor

ON

K-T

YT

-466

5-12

4-43

ON

K-T

YT

-466

5-12

4-60

ON

K-K

PE

1-46

65-5

1-5

ON

K-K

PE

1-4

665-

51-1

7,8

ON

K-K

PE

1-46

65-5

1-3

0O

NK

-KP

E1-

4665

-51

-40

ON

K-K

PE

1-46

65-5

1-7

2O

NK

-KP

E3-

4665

-47-

0O

NK

-KP

E3-

4665

-47

-0-f

loor

ON

K-M

KU

-466

5-93

-0

Jn v

alue



0

1

2

3

4

5

6

7

8

9

10

11

12

Jn v

alu

e



26

Figure 2-27. The distribution of the median joint set number values in the ONKALO access tunnel.

Table 2-7. Basic statistics of the Jn value in different tunnel sections. Calculated from median values.

1 2 3 4 5

(0-1200m)(1200-

2400m)(2400-

3600m)(3600-

4390m)(4390-

4987m)Demonstration Tunnel Level

Technical Rooms Level

-457 level All

n 236 244 252 150 62 47 71 19 1081

median 4 1 2 2 2 2 3 2 2

max 9 4 6 4 4 6 4 3 6

min 1 0.5 0.5 0.5 0.5 0.5 0.5 1 0.5

25-% 3 0.5 0.5 1 1 1 1 2 1

75-% 6 2 3 3 3 3 3 3 3

Parameter

Section

27

Figure 2-28. Illustration of the basic statistics of the Jn value. The grey area represents the minimum and maximum of the Jn values. Calculated from median values.

2.3 Fracture intensity, RQD value

The Rock Quality Designation index (RQD) was developed by Deere (Deere et al., 1967) to provide a quantitative estimate of rock mass quality from drill core logs. RQD is defined as the percentage of intact core pieces longer than 100 mm in the length of core being considered. When no core is available but discontinuity traces are visible in surface exposures or exploration adits, the RQD may be estimated from the number of discontinuities per unit volume (Palmström 1982). The suggested relationship for clay-free rock masses is:

RQD = 115 - 3.3 Jv (1)

where Jv is the sum of the number of joints per unit length for all joint (discontinuity) sets known as the volumetric joint count.

The first quotient (RQD/Jn) of the rock tunnelling quality index (Q = RQD/Jn · Jr/Ja · Jw/SRF) represents the structure of the rock mass. It is a crude measure of the block or

28

particle size, with the two extreme values (100/0.5 and 10/20) differing by a factor of 400. If the quotient is interpreted in units of centimetres, the extreme 'particle sizes' of 200 to 0.5 cm are seen to be crude but fairly realistic approximations. Probably the largest blocks will be several times this size and the smallest fragments less than half the size (Hoek 2007).

The ONKALO tunnel RQD values have been estimated by 1 m long scanlines for each 5 m long tunnel section. For this report, RQD data is available up to chainage 4990 m. From chainage 1200 m, the fracture intensity starts to decrease. The mean RQD value in the ONKALO access tunnel from chainage 0 to 4990 m is 97 %. Logged RQD values for the ONKALO chainage range 0–4990 m are presented in Figure 2-29.

The minimum RQD value is 10% at chainage 2327 m. The width of this zone is 0.2 m. This zone intersection (Zone ID ONK-BFI-232700-232810) is composed of core with TCF (Tunnel Crossing Fracture) fractures and small damage zones on both sides of the core. A horizontal fracture set intersects this zone intersection. Another zone intersection (ONK-BFI-232400-232550) in the roof also crosses this one.

At chainage 2481 m, the RQD value is 30% and the width of the zone is 0.3 m. This is where brittle deformation zone OL-BFZ100 intersects the ONKALO tunnel. This zone also intersects the tunnel at chainage 900–910 m, where the RQD value is approximately 70 %.

An area of high fracture intensity with a significant width can be found at chainage 285 m to 295 m where the RQD value is 50 %. Chainage 292–295 m contains a BFI (Brittle Fault zone Intersection), which is composed of several moderately dipping filled fractures.

Another low value section, 55 % < RQD < 65 %, is apparent at chainage 260 m to 274 m, where the Brittle Fault zone Intersection (ONK-BFI-24250-28700) is composed of a single sub-horizontal fracture. This fracture has a trace length of approximately 50 m and it was visible on both walls. The clay-filled fracture is surrounded by a 40 cm wide zone of soft and weathered rock in the latter part (chainage 280–285 m) of the intersection.

The Brittle Fault zone Intersection ONK-BFI-48830-48900 at chainage 495–510 m is composed of a single slickenside fracture with a visible trace length of ca. 70 m, reaching the tunnel roof at chainage 513 m. In places this fracture branches into several fractures with the same direction as the main fracture.

The significant drop in RQD value around chainage 3300 m is caused by an intersection with OL-BFZ020a and OL-BFZ020b.

No significantly low RQD values are apparent in the last access tunnel section with the only significantly low RQD value (50 %) located at chainage 4383 m, where BFZ-45 (BFI-4377) intersects the access tunnel. At deeper levels BJI-4698 and crosscutting BFI-4754 are observed on the right wall and do not influence RQD values markedly.

29

The demonstration tunnel level has the lowest RQD values in contrast to the technical rooms and -457 levels: its mean RQD is 89 %. The dispersion of RQD values at this level is also high as a result of several brittle fault zone intersections. The demonstration tunnels contain remarkably low RQD values in places (Figure 2-30): the lowest values are observed in demonstration tunnel 2, where the RQD value drops to 20 % as a consequence of BFI-22.3. In demonstration tunnel 1 the variation of RQD values is high. The lowest values are mapped at chainage 31.7 m (30 %), 56.3 m (20 %), and 62.5 m (20 %) due to fault zone intersections. A ductile zone intersection is also evident at chainage 56.3 m.

No significant drops in RQD values are apparent at the technical rooms and -457 levels and are therefore not illustrated by a diagram in this report. Their mean RQD value is 100 %.

Figure 2-29. Logged RQD values for the ONKALO chainage range 0–4990 m.

0

10

20

30

40

50

60

70

80

90

100

0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000 4250 4500 4750

RQ

D v

alu

e

Tunnel chainage (m)

RQD value

RQD value (30 period moving average)

30

Figure 2-30. Logged RQD values for the ONKALO demonstration tunnel level.

The drillhole RQD data was recorded for 1 m long sections. The median values for the depth ranges 0…-120 m and -120…-250 were calculated for the deep drillholes (drillholes which extend at least to the level z = -250). The average RQD values of these median values are 98 % between 0…-120 m and 99 % between -120…250 m (Figure 2-31). RQD anomalies are largely related to brittle deformation zones, as seen e.g. in drillhole OL-KR9 (Figure 2-32).

Figure 2-31. Median values of the RQD (% values) recorded over one meter sections for different drillholes.

0

10

20

30

40

50

60

70

80

90

100

RQ

D v

alu

e

70

75

80

85

90

95

100

OL-

KR

1O

L-K

R2

OL-

KR

3O

L-K

R4

OL-

KR

5O

L-K

R6

OL-

KR

7O

L-K

R8

OL-

KR

9O

L-K

R10

OL-

KR

11O

L-K

R12

OL-

KR

13O

L-K

R14

OL-

KR

15O

L-K

R16

OL-

KR

17O

L-K

R18

OL-

KR

19O

L-K

R20

OL-

KR

21O

L-K

R22

OL-

KR

23O

L-K

R24

OL-

KR

25O

L-K

R26

OL-

KR

27O

L-K

R28

OL-

KR

29O

L-K

R30

OL-

KR

31O

L-K

R32

OL-

KR

33O

L-K

R35

OL-

KR

36O

L-K

R37

OL-

KR

38O

L-K

R39

OL-

KR

40O

L-K

R46

OL-

KR

48O

L-K

R49

OL-

KR

50O

L-K

R51

OL-

KR

52O

L-K

R54

OL-

KR

55O

L-K

R56

OL-

KR

57

RQ

D [

%]

z=0…‐120 m

z=‐120…‐250 m

31

Figure 2-32. Correlation between RQD anomalies and brittle deformation zones in the drillhole OL-KR9.

0

10

20

30

40

50

60

70

80

90

100

40 80 120 160 200 240 280 320 360 400 440 480 520 560 600

RQ

D [

%]

length [m]

BF

Z-0

11

BF

Z-0

20a

BF

Z-0

20b

BF

Z-1

75

BF

Z-3

23

32

Figure 2-33 depicts how the rock quality changes with increasing depth, making it necessary to separate the more fractured surface region from the rest of the drillhole data in order to obtain a more realistic estimation of the RQD value.

Figure 2-33. The variation of the RQD-value with the depth levels in the drillhole OL-KR22 (Kuula 2010).

2.4 Fracture length and end type

The fracture trace length data distributions are both truncated and censored: truncation occurs when fractures below a certain length are ignored, censoring occurs when fracture trace lengths above a certain length cannot be observed in their entirety because of the limited dimensions of the excavation. For all fractures, both their length and end-type are mapped — a fracture can end in intact rock (R), at another fracture (J), or continue beyond the tunnel (C).

The distribution of fracture end data is relatively similar in every section. Most of the short fractures end in rock and the long fractures continue beyond the tunnel (Figure 2-34, Figure 2-35). The distribution seems to become more uniform with increasing depth. Note that the end-type has no correlation with the fracture set.

-450

-400

-350

-300

-250

-200

-150

-100

-50

0

0 10 20 30 40 50 60 70 80 90 100 110RQD-%

Depth

RQD

Median 0-120m

Median 120-250m

OL-BFZ106

High density fracturing

OL-BFZ019c

OL-BFZ100OL-BFZ122OL-BFZ129

OL-BFZ020a

OL-BFZ020b

OL-BFZ019a

33

Figure 2-34. Trace length and end-type for all mapped fractures in the ONKALO tunnel chainage range 0–4390 m. For the x-axis, the fracture can end in intact rock (R), at another fracture (J), or continue beyond the tunnel (C), with the two letters, e.g. RR indicating both ends of the fracture.

RR RJ RC CC JJ JC

< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

≥20 m, n=47

Percentile

Fracture end type (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

RR RJ RC CC JJ JC

< 0.5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

≥20 m, n=30


Fracture length

RR RJ RC CC JJ JC

< 0.5 m, n=2051

< 1 m, n=2207

< 2 m, n=2269

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=406

≥ 20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

RR RJ RC CC JJ JC

< 0.5 m, n=471

< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=289

≥ 20 m, n=25


Fracture length

34

Figure 2-35. Trace length and end-type for all mapped fractures in the ONKALO tunnel chainage range 4390-4990 m and technical rooms levels. For the x-axis, the fracture can end in intact rock (R), at another fracture (J), or continue beyond the tunnel (C), with the two letters, e.g. RR indicating both ends of the fracture.

< 0.5 m, n=192

< 1 m, n=432

< 2 m, n=525

< 3 m, n=191

< 4 m, n=84

< 5 m, n=41

< 20 m, n=91

≥ 20 m, n=14

RR RJ RC CC JJ JC

Fracture length

Percentile


< 0.5 m, n=96

< 1 m, n=375

< 2 m, n=385

< 3 m, n=141

< 4 m, n=62

< 5 m, n=31

< 20 m, n=55

≥ 20 m, n=4

RR RJ RC CC JJ JC

Fracture length

Fracture end type (demonstration tunnel level)

< 0.5 m, n=166

< 1 m, n=533

< 2 m, n=635

< 3 m, n=234

< 4 m, n=94

< 5 m, n=49

< 20 m, n=86

≥ 20 m, n=23

RR RJ RC CC JJ JC

Fracture length

Percentile

Fracture end type (technical rooms level)

< 0.5 m, n=55

< 1 m, n=118

< 2 m, n=168

< 3 m, n=65

< 4 m, n=25

< 5 m, n=10

< 20 m, n=18

≥ 20 m, n=0

RR RJ RC CC JJ JC

Fracture length

Fracture end type (-457 level)

35

Fractures are found to become longer with increasing tunnel length. Despite this the shortest fractures are not located at the shallowest levels: chainage range 1200–2400 m contains the shortest fractures. The cumulative distribution of fracture length at different depth levels is illustrated in Figure 2-36.

Figure 2-36. Cumulative distribution of fracture length at different depths in the ONKALO facility.

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0 1 2 3 4 5 6

Fracture length (m)

0-1200

1200-2400

2400-3600

3600-4390

4390-4990 + technical roomslevels

36

In the first 2400 m chainage, the mean fracture length varies from 0.5 m to 1.5 m, depending on the major fracture set. The length of the moderately dipping fractures (Set 4) seems to be greater than the length of the vertical or random fractures, but this is partly caused by the orientation of the tunnel, which biases the data (Figure 2-37; Kuula 2010).

Figure 2-37. Cumulative distribution of trace lengths for different fracture sets for all mapped fractures in the ONKALO tunnel, 0–2400 m chainage.

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

Fracture length (m)

Set 1, 08°/065°

Set 2, 89°/081°

Set 3, 85°/359°

Set 4, 32°/135°

Others

37

In the chainage range 2400–4390 m, the mean fracture length varies from 0.8 m to 1.2 m, depending on the major fracture set. In these deeper sections of the tunnel, the fracture length distribution of moderately dipping set B is more similar compared to other sets (Figure 2-38; Mönkkönen et al. 2012).

Figure 2-38. Cumulative distribution of trace lengths for different fracture sets for all mapped fractures in the ONKALO tunnel, 2400-4390 m chainage.

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

Fracture length (m)

Set A, 90°/084°

Set B, 05°/043°

Set C, 89°/338°

Others

38

In chainage range 4390–4990 m, the mean fracture length varies between 1.3 m and 2.7 m, thus the fractures are longer at deep levels. Sets C and C2 consist of shorter fractures than other sets. Set B2 fractures have the most notable variation in fracture length (Figure 2-39).

Figure 2-39. Cumulative distribution of trace lengths for different fracture sets for all mapped fractures in the ONKALO tunnel, 4390–4990 m chainage.

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

Fracture length (m)

Set A, 89°/264°

Set B2, 25°/342°

Set C, 90°/338°

Set C2, 61°/334°

Others

39

At the demonstration tunnel level the mean fracture length varies between 1.4 m and 3.2 m. The longest fractures are included in south-dipping set D2, which differs significantly from the other sets (Figure 2-40).

Figure 2-40. Cumulative distribution of trace lengths for different fracture sets for all mapped fractures in the demonstration tunnel level.

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0

Fracture length (m)

Set A, 90°/262°

Set C2, 60°/335°

Set D, 52°/181°

Others

40

At the level of the technical rooms the mean fracture length varies from 1.4 m to 2.9 m. Set B2 which dips gently to the north has the most significant variation in fracture length and also has the highest mean fracture length (Figure 2-41).

Figure 2-41. Cumulative distribution of trace lengths for different fracture sets for all mapped fractures at the level of the technical rooms.

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0

Fracture length (m)

Set A, 88°/261°

Set B2, 26°/346°

Set C, 88°/338°

Others

41

-457 level fractures have the lowest distribution in fracture length. The mean fracture length is approximately 1.7 m in all fracture sets. Cumulative distribution curves are similar due to similar fracture length distribution and a small observation area (Figure 2-42).

Figure 2-42. Cumulative distribution of trace lengths for different fracture sets for all mapped fractures in -457 level.

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

Fracture length (m)

Set A, 88°/260°

Set B2, 28°/338°

Others

42

43

3 MECHANICAL PROPERTIES OF FRACTURES

The second quotient (Jr/Ja) of the rock tunnelling quality index (Q = RQD/Jn · Jr/Ja · Jw/SRF) represents the roughness and frictional characteristics of the joint walls or filling materials. This quotient is weighted in favour of rough, unaltered joints in direct contact. It is to be expected that such surfaces may be close to the peak strength and will dilate strongly when sheared, and are therefore especially favourable for tunnel stability.

When rock joints have even thin clay mineral coatings and fillings, their strength is significantly reduced. However, rock wall contact after small shear displacements may be an important factor for preserving the excavation from ultimate failure. Where no rock wall contact exists, the conditions are extremely unfavourable to tunnel stability.

The 'friction angles' are a little below the residual strength values for most clays, and are possibly down-graded by the fact that these clay bands or fillings may tend to consolidate during shear, at least if normal consolidation or if softening and swelling has occurred (Hoek 2007).

3.1 Fracture surface parameters, Jr and Ja values

The fracture roughness number, Jr, can have values between 0.5 and 4: the lowest values are for planar slickensided fractures and the highest for discontinuous or rough and undulating fractures.

With increasing depth in the access tunnel fractures become smoother and more planar and the mean Jr value drops from 3 to 1.5. Only the amount of long slickensided fractures decreases with depth. The mean amount of slickenside fractures is less than 10%, (Figure 3-1, Figure 3-2). The Jr value distribution observed in the access tunnel between chainages 1200–4990 m resembles the distribution observed at the demonstration tunnel, technical rooms and pumping station levels. Figure 3-3 shows visually the distribution of the median joint roughness number values in the ONKALO access tunnel.

In section 1, the vertical N-S trending fracture set, Set 2, has more smooth and planar fractures and fewer rough and undulating fractures than the other sets. The fracture end-type does not appear to correlate with roughness (Kuula 2010). This section differs from deeper chainages (Figure 3-1) and the other levels analysed in this report.

Section 5 and the technical rooms levels exhibit a fracture roughness which is fairly similar in all of the sets except Set D. Over 50 % of the fractures in sets A, B2, C and C2 have a Jr of 1–1.5. Only Set D which is observed at the demonstration tunnel level contains clearly rougher fractures: ~70 % its fractures have a Jr value of over 1.5.

The Jr-value is also calculated from the drillhole data. The median values from depth ranges 0…-120 m, -120…-250 m and >250 m were calculated for deep drillholes (drillholes which extend at least to level z = -250 m). The median value of Jr is commonly 3 and it declines to 2 when exceeding a depth of 250 m. The same correlation with depth and fracture surface roughness is observed in tunnel mapping data, so the fractures become more planar at deeper levels.

44

Figure 3-1. The distribution of the joint fracture roughness number Jr over different fracture lengths for all mapped fractures in the ONKALO tunnel chainage 0–4390 m.

0.5 1 1.5 2 3 4

< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

≥ 20 m, n=47

Percentile

Jr value (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0.5 1 1.5 2 3 4

< 0.5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

≥ 20 m, n=30


Fracture length

0.5 1 1.5 2 3 4

< 0.5 m, n=2051

< 1 m, n=2207

< 2 m, n=2272

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=406

≥ 20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0.5 1 1.5 2 3 4

< 0.5 m, n=471

< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=290

≥ 20 m, n=27


Fracture length

45

Figure 3-2. The distribution of the joint fracture roughness number Jr over different fracture lengths for all mapped fractures in the ONKALO tunnel chainage 4390–4990 m and technical rooms levels.

< 0.5 m, n=192

< 1 m, n=432

< 2 m, n=525

< 3 m, n=191

< 4 m, n=84

< 5 m, n=41

< 20 m, n=92

≥ 20 m, n=15

0.5 1 1.5 2 3 4

Percentile

Fracture length


< 0.5 m, n=167

< 1 m, n=533

< 2 m, n=633

< 3 m, n=239

< 4 m, n=98

< 5 m, n=54

< 20 m, n=91

≥ 20 m, n=29

0.5 1 1.5 2 3 4

Fracture length

Percentile

Jr value (technical rooms level)

< 0.5 m, n=55

< 1 m, n=118

< 2 m, n=168

< 3 m, n=65

< 4 m, n=25

< 5 m, n=10

< 20 m, n=18

≥ 20 m, n=0

0.5 1 1.5 2 3 4

Fracture length

Jr-value (-457 level)

46

Figure 3-3. The distribution of the median joint roughness number values in the ONKALO access tunnel.

The fracture alteration number, Ja, can have values between 0.5 and 20. The lowest values are for tightly-healed and unaltered fractures, where the rock walls are in contact, and the highest for thick mineral-filled fractures (Mönkkönen et al. 2012).

The Ja value correlates with fracture length: the shortest fractures are more often unaltered or slightly altered (Ja is 1 or 2) in the whole ONKALO area whereas medium length and long fractures often have softening or low friction clay mineral coatings (Ja=4) or thin or thick mineral filling and can shear without rock wall contact (Ja ≥ 5) (Mönkkönen et al. 2012). In the deepest part of the access tunnel between chainages 4390–4990 m the Ja values no longer vary significantly between short and long fractures. Figure 3-6 shows the distribution of the median joint alternation values in the ONKALO access tunnel.

For chainages 0–1200 m, the mean Ja value is approximately 4. For very short fractures (length 1 m or less), the mean Ja value is 1 (Kuula 2010). In the deeper sections of the access tunnel (chainages 1200–4990 m), fractures are less altered; Ja values drop clearly after the first section of the tunnel. For longer fractures (20 m), the Ja value varies mainly between 2–3, except in the last section of the access tunnel where the Ja value varies between 1–3 and at times can even be under 1 (Figure 3-4, Figure 3-5).

The same trend of correlation between joint alteration and fracture length is also found at the demonstration tunnel-, technical rooms- and -457 levels. As the demonstration tunnel level is situated between access tunnel chainages 4366 and 4512, long fractures with high, ≥4 Ja values are still observed at this level. At the deeper technical rooms- and -457 levels long and mineral filled fractures are absent. Strongly altered fractures are clearly reduced at -457 level located at the greatest depth (Figure 3-5).

Compared to other fracture sets in the 0–2400 m chainage range, set 4 has more altered fracture surfaces. Between chainages 2400–4390 m the joint alteration of Set A and Set C resembles each other: more than half of the fractures in both sets are unaltered or

47

slightly altered fractures with a Ja value of 0.75 or 1, whereas Set B contains a comparatively high amount of mineral-filled fractures.

Both section 5 and the technical rooms levels exhibit a fairly similar joint alteration in all sets except in Set D. Over 75 % of the fractures in sets A, B2, C and C2 have a Ja under 2. Only Set D fractures when observed at the demonstration tunnel level often exhibit softening or low friction clay mineral coatings (Ja = 4) or thin or thick mineral filling and can shear without rock wall contact (Ja ≥ 5).

The Ja value is also studied from drillhole data which was edited to 1 meter long composites and the median values for the depth ranges 0…-120 m, -120…-250 m and >250 m. Values were calculated only for the deep drillholes (which extended to a depth of at least z = -250 m). The median value of Ja is commonly 2 and no correlation with depth can be observed.

Figure 3-4. The distribution of joint alternation number Ja values over different fracture lengths for all mapped fractures in the ONKALO tunnel, chainage 0 –4390 m.

0.75 1 2 3 4 ≥5

< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

≥ 20 m, n=47

Percentile

Ja value (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0.75 1 2 3 4 ≥5

< 0,5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

≥ 20 m, n=30


Fracture length

0.5 1 1.5 2 3 4

< 0.5 m, n=2051

< 1 m, n=2208

< 2 m, n=2272

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=406

≥ 20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

48

Figure 3-5. The distribution of joint alternation number Ja values over different fracture lengths for all mapped fractures in the ONKALO tunnel, chainage 4390–4990 m and the technical rooms levels.

< 0.5 m, n=192

< 1 m, n=432

< 2 m, n=525

< 3 m, n=191

< 4 m, n=84

< 5 m, n=41

< 20 m, n=91

≥ 20 m, n=14

0.75 1 2 3 4 ≥5

90 %-100 %80 %-90 %70 %-80 %60 %-70 %50 %-60 %40 %-50 %30 %-40 %20 %-30 %10 %-20 %0 %-10 %

Fracture length

Percentile


< 0.5 m, n=96

< 1 m, n=375

< 2 m, n=385

< 3 m, n=141

< 4 m, n=62

< 5 m, n=31

< 20 m, n=55

≥ 20 m, n=4

0.75 1 2 3 4 ≥5

Fracture length

e

Ja value (demonstration tunnel level)

< 0.5 m, n=55

< 1 m, n=118

< 2 m, n=168

< 3 m, n=65

< 4 m, n=25

< 5 m, n=10

< 20 m, n=18

≥ 20 m, n=0

0.75 1 2 3 4 ≥5

Fracture length

Percentile

Ja value (Technical Rooms level)

< 0.5 m, n=62

< 1 m, n=132

< 2 m, n=188

< 3 m, n=68

< 4 m, n=26

< 5 m, n=12

< 20 m, n=21

≥ 20 m, n=0

0.75 1 2 3 4 ≥5

Fracture length

Ja (-457 level)

49

Figure 3-6. The distribution of the median joint alternation number values in the ONKALO access tunnel.

3.2 Fracture filling mineralogy

The fracture filling mineralogy of the ONKALO access tunnel is formerly studied in four parts; chainage 0–990 m (Nordbäck et al. 2008), 990–1980 (Nordbäck & Engström 2010), 1980–3116 (Nordbäck 2010) and 3116–4986 (Nordbäck 2013). The division of the access tunnel is therefore incongruent with this report.

The fracture filling mineralogy is analysed by visual observations during geological mapping of the access tunnel. This is done by identifying a mineral from at least one point at the fracture surface. Fracture filling thickness and mineralogy vary along a fracture surface (Nordbäck 2013).

The distribution of all mapped fracture filling minerals is presented in Figure 3-7. The proportion of some minerals, e.g. calcite stays constant at all depths. By contrast the proportion of some minerals, e.g. kaolinite, is significantly lower at deeper levels in ONKALO. The variation of the most common fracture filling minerals with increasing depth is presented in Figure 3-8.

50

Figure 3-7. The most common fracture filling minerals in chainage range 0–4986 m.

51

Figure 3-8. Variation of the most common fracture filling minerals with increasing depth.

The most common filling minerals of chainage 0–990 are kaolinite (47 %), calcite (44 %), pyrite (44 %), chlorite (30 %) and biotite (10 %). Small amounts of epidote (4.4 %), unidentified clay minerals (4.1 %), graphite (0.8 %), muscovite (0.7 %), quartz (0.7 %), illite (0.6 %), hematite (0.3 %) and sericite (0.2 %; Nordbäck et al. 2008). The frequency of these fracture filling minerals is presented in Figure 3-9.

Between chainages 990–1980 the most common filling minerals are calcite (40 %), pyrite (22%), kaolinite (21 %), chlorite (8 %), epidote (3 %) and muscovite (2 %). Small amounts of unidentified clay minerals (0.9 %), quartz (0.5 %), graphite (0.4 %), illite (0.4 %), pyrrhotite (0.1 %) and sericite (0.1 %) were also observed. 0.5 % of the fractures included pregrouting cement (Nordbäck & Engström 2010). The frequency of these fracture filling minerals is presented in Figure 3-10.

In chainage range 1980–3116 the most common filling minerals are calcite (48.6 %), pyrite (22.8 %), chlorite (9.2 %), kaolinite (4.8 %), epidote (4.5 %), muscovite (3.3 %), quartz (2.2 %), biotite (1.4 %) and illite (1 %). Small amounts of graphite (0.9 %), unidentified clay minerals (0.7 %), pyrrhotite (0.04 %) and sericite (0.03 %) are also observed in some fractures. Pre-grouting cement (0.1 %) is also found at the fracture surfaces (Nordbäck 2010). The frequency of these filling minerals is presented in Figure 3-11.

0

10

20

30

40

50

60

0‐990 990‐1980 1980‐3116 3116‐4986

percentage of all m

apped fractures (%

)

chainage range of analysed sections (m)

kaolinitecalcitepyritechlorite

52

In the last analysed chainage section 3116–4986 m the most common filling minerals are calcite (50.0 %), pyrite (13.3 %), chlorite (8.4 %), kaolinite (8.0 %), quartz (7.3 %), muscovite (3.7 %), illite (2.6 %), epidote (1.7 %), clay (1.6 %), graphite (1.4 %) and biotite (0.7 %). 0.9 % of the fractures exhibit pre-grouting cement (Nordbäck 2013). The Frequency of these fracture filling minerals is presented in Figure 3-12.

Figure 3-9. Fracture filling mineralogy in the ONKALO chainage 0–900 m. Biotite (BT), calcite (CC), epidote (EP), graphite (GR), hematite (HE), pre-grouting cement (IN), illite (IL), kaolinite (KA), chlorite (KL), quartz (KV), muscovite (MU), pyrite (SK), sericite (SR) and unidentified clay minerals (SV) (Nordbäck et al. 2008).

53

Figure 3-10. Fracture filling mineralogy in the ONKALO chainage 990–1980 m. Biotite (BT), calcite (CC), epidote (EP), graphite (GR), hematite (HE), pre-grouting cement (IN), illite (IL), kaolinite (KA), chlorite (KL), quartz (KV), muscovite (MU), pyrite (SK), sericite (SR) and unidentified clay minerals (SV) (Nordbäck & Engström 2010).

54

Figure 3-11. Fracture filling mineralogy in the ONKALO chainage 1980–3116 m. Biotite (BT), calcite (CC), epidote (EP), graphite (GR), hematite (HE), pre-grouting cement (IN), illite (IL), kaolinite (KA), chlorite (KL), quartz (KV), muscovite (MU), pyrite (SK), sericite (SR) and unidentified clay minerals (SV) (Nordbäck 2010).

55

Figure 3-12. Fracture filling mineralogy in the ONKALO access tunnel chainage 3116–4986 m. Biotite (BT), calcite (CC), epidote (EP), graphite (GR), hematite (HE), pre-grouting cement (IN), illite (IL), kaolinite (KA), chlorite (KL), quartz (KV), muscovite (MU), pyrite (SK), sericite (SR) and unidentified clay minerals (SV) (Nordbäck 2013).

3.3 Fracture friction angle

Friction angles of the fracture surfaces can be estimated from the Jr and Ja values, being atan (Jr/Ja). The first and the second section differ from the deeper parts of the tunnel to a certain degree. Sections 3 to 5 and technical rooms levels are similar (Figure 3-14, Figure 3-15). Basically the friction angle of short fractures is always fairly equal regardless of depth but longer fractures contain more variation.

In the first section, chainage range 0 to 1200 m, the friction angle is mainly between 30°– 40° but the distribution is fairly uniform (Kuula 2010). In the second section of the

56

tunnel (chainage 1200 to 2400 m), the friction angle increases for almost all fracture lengths, ranging from 40° to 60°. The more the fractures lengthen in chainage 2400–4390 m, the greater the friction angle rises except the longest (>5 m) fractures. Between chainages 2400 to 4990 m and when including the technical rooms levels, the friction angle value is 50°– 60° for short fractures (<5 meters) and 20°– 30° for longer fractures. At the technical rooms level there is also a concentration of 4–5 m long fractures with a friction angle value of 40–50°.

In Q logging, the fracture friction angle is determined using equation φ+i = atan (Jr/Ja). In this equation “i” consists of a geometrical component and an asperity failure component. The determined value is the effective friction angle and is not directly comparable with the fracture friction angle φ determined in the laboratory. Some typical values for different joint types are presented in Figure 3-13 (Barton 2002).

Figure 3-13. Friction angles of different fracture types (Barton 2002).

57

Figure 3-14. Friction angle and fracture length for all mapped fractures in the ONKALO tunnel, chainage 0–4390 m.

0 - 10° 10 - 20° 20 - 30° 30 - 40° 40 - 50° 50 - 60° ≥ 60°

< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

≥ 20 m, n=47

Percentile

Friction angle (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0 - 10° 10 - 20° 20 - 30° 30 - 40° 40 - 50° 50 - 60° ≥ 60°

< 0.5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

≥ 20 m, n=30


Fracture length

0-10° 10-20° 20-30° 30-40° 40-50° 50-60° >60°

< 0.5 m, n=2051

< 1 m, n=2208

< 2 m, n=2272

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=405

≥ 20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0-10° 10-20° 20-30° 30-40° 40-50° 50-60° >60°

< 0.5 m, n=471

< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=290

≥ 20 m, n=27


Fracture length

58

Figure 3-15. Friction angle and fracture length for all mapped fractures in the ONKALO tunnel, chainage 4390–4990 m and the technical rooms.

3.4 Fracture undulation

Fracture undulation is defined via the amplitude of a 1 m long straight inspection line. For chainage 0–1200 m, the undulation is mainly 20–50 mm, with the value not changing in deeper parts of the tunnel (Figure 3-16). The shortest fractures are the most planar. The main change from section 1 to section 2 concerns the fractures with lengths in excess of 20 m, where the mean undulation increases from 0 mm to 20–50 mm. In sections 3 and 4 the undulation varies almost linearly from 0 mm (fractures < 1 m) to 20–25 mm (fractures >20 m; Mönkkönen et al. 2012). In section 5 fracture length shortens and the amount of undulation decreases slightly. Decreasing undulation with depth is also discovered by comparing the three technical rooms levels (Figure 3-17).

< 0.5 m, n=192

< 1 m, n=432

< 2 m, n=525

< 3 m, n=191

< 4 m, n=84

< 5 m, n=41

< 20 m, n=91

≥ 20 m, n=14

0-10° 10-20 20-30 30-40 40-50 50-60 60-70

Percentile


Fracture length

< 0.5 m, n=96

< 1 m, n=375

< 2 m, n=385

< 3 m, n=141

< 4 m, n=62

< 5 m, n=31

< 20 m, n=55

≥ 20 m, n=4

0-10° 10-20° 20-30° 30-40° 40-50° 50-60° ≥60°

Fracture length

Friction angle (demonstration tunnel level)

< 0.5 m, n=167

< 1 m, n=533

< 2 m, n=635

< 3 m, n=233

< 4 m, n=94

< 5 m, n=49

< 20 m, n=83

≥ 20 m, n=21

0-10° 10-20° 20-30° 30-40° 40-50° 50-60° ≥60°

Fracture length

Percentile

Friction angle (technical rooms level)

< 0.5 m, n=57

< 1 m, n=125

< 2 m, n=177

< 3 m, n=65

< 4 m, n=26

< 5 m, n=12

< 20 m, n=20

≥ 20 m, n=0

0-10° 10-20° 20-30° 30-40° 40-50° 50-60° ≥60°

Fracture length

Friction angle (-457 level)

59

Figure 3-16. Fracture undulation and fracture length for all mapped fractures in the ONKALO tunnel, chainage 0–4390 m.

0 cm 0-2 cm 2-5 cm 5-10 cm ≥10 cm

< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

≥ 20 m, n=47

Percentile

Undulation (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0 cm 0-2 cm 2-5 cm 5-10 cm ≥10 cm

< 0.5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

≥ 20 m, n=30


Fracture length

0 cm 0-2 cm 2-5 cm 5-10 cm >10 cm

< 0.5 m, n=2051

< 1 m, n=2208

< 2 m, n=2272

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=406

≥ 20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0 cm 0-2 cm 2-5 cm 5-10 cm >10 cm

< 0.5 m, n=471

< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=290

≥ 20 m, n=27


Fracture length

60

Figure 3-17. Fracture undulation and fracture length for all mapped fractures in the ONKALO tunnel, chainage 4390–4990 m and the technical rooms levels.

< 0.5 m, n=192

< 1 m, n=432

< 2 m, n=525

< 3 m, n=191

< 4 m, n=84

< 5 m, n=41

< 20 m, n=91

≥ 20 m, n=14

0 cm 0-2 cm 2-5 cm 5-10 cm ≥10 cm

80 %-90 %70 %-80 %60 %-70 %50 %-60 %40 %-50 %30 %-40 %20 %-30 %10 %-20 %0 %-10 %

Fracture length

Percentile


< 0.5 m, n=96

< 1 m, n=375

< 2 m, n=385

< 3 m, n=141

< 4 m, n=62

< 5 m, n=31

< 20 m, n=55

≥ 20 m, n=4

0 cm 0-2 cm 2-5 cm 5-10 cm ≥10 cm

Undulation (demonstration tunnel level)

Fracture length

< 0.5 m, n=190

< 1 m, n=596

< 2 m, n=704

< 3 m, n=283

< 4 m, n=106

< 5 m, n=55

< 20 m, n=101

≥ 20 m, n=23

0 cm 0-2 cm 2-5 cm 5-10 cm ≥10 cm

80 %-90 %70 %-80 %60 %-70 %50 %-60 %40 %-50 %30 %-40 %20 %-30 %10 %-20 %0 %-10 %

Fracture length

Undulation (technical rooms level)

Percentile

< 0.5 m, n=192

< 1 m, n=432

< 2 m, n=525

< 3 m, n=191

< 4 m, n=84

< 5 m, n=41

< 20 m, n=91

≥ 20 m, n=14

0 cm 0-2 cm 2-5 cm 5-10 cm ≥10 cm

Undulation (-457 level)

Fracture length

61

3.5 Schmidt hammer measurements

The Schmidt hammer test is one of the most commonly applied index tests for rock strength in addition to the Point Load test. The reliability and consistency of this inexpensive and quick measurement depends on the hammer type, normalization of rebound values, specimen dimensions, surface smoothness, weathering and moisture content. Testing, data reduction and analysis also influence the test results (Aydin & Basu 2005).

The Schmidt hammer consists of a spring loaded piston and plunger. The measurement is conducted by pressing the hammer orthogonally against a surface which automatically releases the piston. The harder the rock is, the shorter the penetration time and hence a greater rebound value. The extent of recovered energy from the impact is expressed as a percentage of the initial length of the key spring before releasing the piston (Aydin 2008).

There are two types of Schmidt hammers; the L-type and the N-type hammer, which are used by Posiva Oy. According to Aydin (2008) the N-type hammer has higher impact energy, 2.207 Nm, thus it is more suitable for harder rocktypes. The impact energy of the L-type hammer is 0.735 Nm. N-type hammer is also less sensitive to surface irregularities and should be preferred in field applications.

The measurements in the ONKALO access tunnel are taken by making 10 impacts on a sanded tunnel wall surface or a fracture surface. The five highest values were averaged and corrected by correction curves to exclude gravitational effects. Downwards and upwards positioned devices have their own correction values. The corrected value from a Schmidt hammer measurement is called the R-value.

Schmidt hammer measurement data for the access tunnel was available for chainage range 3503–4980 m. The rock type at each location was documented during measurement. The results from the ONKALO access tunnel and the technical rooms levels are presented in Figure 3-18 to Figure 3-21. The affect of the rock type on the strength of the rock is seen clearly in Figure 3-18. Pegmatitic granite exhibits slightly higher values than veined gneiss which is in agreement with uniaxial compressive strength measurements. The amount of data on migmatitic and stromatitic gneiss is inadequate for interpretation.

Valli (2010) has also determined the R-values for personnel and exhaust air shaft. The results illustrated in Figure 3-22 were determined from a cage lift from both the personnel and exhaust air shafts. Tests were terminated before the roof of the shaft access niche at the -180 level. Results indicate a correlation with depth i.e. the rock is stronger at deeper levels.

62

Figure 3-18. Schmidt hammer values for different rock types in the ONKALO tunnel, chainage 3500–4980 m. The chart contains all of the measured values from the access tunnel. VGN=veined gneiss, MGN=migmatitic gneiss, PGR=pegmatitic granite, SGN=stromatitic gneiss. Values obtained after the red dashed line are not comparable with other values due to a repaired Schmidt hammer.

0

10

20

30

40

50

60

70

80

90

100

3500 3600 3700 3800 3900 4000 4100 4200 4300 4400 4500 4600 4700 4800 4900 5000

R‐value from Schmidt ham

mer

Tunnel chainage (m)

VGNMGNPGRSGN

63

Figure 3-19. Schmidt hammer values for different rock types at the demonstration tunnel level.

Figure 3-20. Schmidt hammer values for different rock types at the technical rooms level.

0

10

20

30

40

50

60

70

80

90

100


mer

VGN

PGR

64

Figure 3-21. Schmidt hammer values for different rock types at -457 level.

Figure 3-22. Schmidt hammer values for personnel and exhaust air shaft. Rock types undetermined. Trendlines are linear.

0

10

20

30

40

50

60

70

80

90

100R‐value from Schmidt ham

mer

VGN

MGN

PGR

DGN

0

10

20

30

40

50

60

70

80

90

100

80 90 100 110 120 130 140 150 160 170 180

r‐value from Schmidt ham

mer

level (m from surface)

personnel shaft

exhaust air shaft

personnel shaft trendline

exhaust air shaft trendline

65

3.6 Summary of fracture mechanical properties

Since Site description report 2011 (Posiva 2013) no new laboratory fracture shear strength tests have been carried out.

The fracture wall compressive strength has been systematically mapped for chainage range 1280–2935 m using the Schmidt hammer. Results from the study by Kuula (2010) shows that the measured values are close to the intact rock strength for coated fracture surfaces and approximately 65% of the intact rock strength for filled fracture surfaces.

The friction angle and cohesion is calculated with the Barton-Bandis failure criterion (Barton & Bandis 1990) and it is presented in Kuula (2010). Because no new data is available, the Barton-Bandis fracture parameters have not been updated.

A summary of the mechanical fracture properties is presented in Table 3-1. The results are based on Q-logging results and some laboratory tests.

66

Table 3-1. Summary of mechanical properties of fractures for chainage 2400 to 4990. Note that the data for chainage 0 to 2400 are included in SR2008 (Kuula 2010).

Joint properties from lab. testing Sets A, B, C

Basic friction angle [º] (1 26.7

JCS0 (laboratory scale) [MPa] (2 115

JRC0 (laboratory scale) 5

L0 (laboratory scale) [m] (3 0.092

Ln (natural block size) [m] (4 1

Intact rock strength [MPa] (5 115 Estimated joint properties (Set)

A

B*

B2

C

C2

D

Mean Dip/Dip direction [°] 89/262 05/043

26/342 89/338

61/335

52/181

JRCn (natural block size) [-] (6 2.3 2.3

2.3 2.3

2.3 8

JCSn (natural block size) [MPa] 80 80 80 80 80 80

Normal stress σn = 0- 2 MPa (7

Friction angle [º](8 28-32 28-32 - 28-32 - -

Cohesion [MPa] 0.1-0.6 0.1-0.7 - 0.1-0.7 - -

Normal stiffness [GPa/m] 200-300 200-300 - 200-300 - -

Shear stiffness [GPa/m] 0.1-0.3 0.1-0.3 - 0.1-0.3 - -

Design dilatation angle [º] 1.5-5.3 1.5-6.0 - 1.5-6.0 - -

Normal stress σn = 0- 10.6 MPa (9

Friction angle [º](8 28-32 28-32 - 28-32 - -

Cohesion [MPa] 0.1-0.6 0.1-0.7 - 0.1-0.7 - -

Normal stiffness [GPa/m] 2500-3000 2500-3000

2500-3000

Shear stiffness [GPa/m] 0-2 0-2 - 0-2 - -

Design dilatation angle [º] 1.0-3.3 1.0-3.7 - 1.0-3.7 - - 1) Average residual friction angle value from laboratory tests on smooth fractures. 2) 100% of intact rock strength. 3) Specimen size at laboratory 92 mm. 4) Natural block size was selected to be equal to the block size of JRC100 value. 5) Mean strength of intact rock specimen. 6) Median values from Q-logging between chainages 4390-4990 m. Fracture length < 5 m. In the calculations, these values were used as fixed input values. 7) Near tunnel perimeter low normal stresses are possible. 8) Effective friction angles at different chainages are discussed in Section “Fracture friction angle” 9) Mean vertical stress at 400 m depth is about 10.6 MPa.

*Fracture Set B values interpreted between chainages 4390-4990 m

67

4 BRITTLE DEFORMATION ZONES

4.1 Location of brittle deformation zone intersections

Estimation of the mechanical properties of the brittle deformation zones (BDZ, BFZ) is based on Olkiluoto area drillholes and the ONKALO tunnel mapping (Engström & Kemppainen, 2008). In this report, 23 fracture zones have been analysed. The locations and sizes of these zones are described in Aaltonen et al. (2010). The intersections of the BFZ’s are updated according to the upcoming Geological Model of the Olkiluoto Site ver. 3.0. Parameterisation of the brittle fault zones has previously been performed in 2011 and thus this study provides an update to the earlier interpretation (Mönkkönen et al. 2012).

The analysed brittle deformation zones have been selected based on their size and location and available data: a direct geological observation of a deformation zone must exist i.e. the deformation zone must intersect a drillhole or the ONKALO access tunnel so that a parameter can be estimated. The analysed brittle deformation zones included all of the zones classified as site-scale brittle deformation zones and which fulfil the criterion of direct geological observation. Also, repository-scale zones which are included in regional stress modelling (Valli et al. 2011) are analysed. These are mainly shallow dipping zones which are located centrally or close to ONKALO and the repository. One of the main BDZ zones is OL-BFZ100 which intersects the tunnel in several places (Figure 4-1). All of the analysed zones are listed in Table 4-1.

Figure 4-1. Brittle deformation zone OL-BFZ100. The deformation zone is coloured based on interpreted rock quality, see the legend.

68

As described in Aaltonen et al. (2010), in the modelling procedure for the deformation zones, each zone is checked and described via those drillholes that penetrate the zone being considered. The intersection points of zones are connected to each other using geophysical and hydrogeological information. From those points, a 3D plane (to the upper and lower boundary of the brittle deformation zone) is created using the Geovia Surpac® software.

The typical ‘architecture’ is shown schematically in Figure 4-2. According to Aaltonen et al. (2010) the brittle deformation zone can be a joint zone or a joint cluster (BJI) when no clear sign of lateral movement is shown. When clear signs of lateral movement are shown, the zone is designated as a fault zone (BFI).

Figure 4-2. A conceptual model of a single fault zone, consisting of a complex branching fault core zone (indicated in black) and an equally complex zone of influence (whose outer margins are indicated by dashed lines). Zones of influence are also usually named as pre and post core zones depending on the direction of the increasing chainage values. Modified from Mattila et al. (2007).

69

Table 4-1. Summary of analysed brittle deformation zones.

4.2 Estimation of strength and deformability properties

Determinations of the strength and deformability properties were based on the rock mass classification technique. This technique has been described by Hudson et al. (2008). The strength and deformation properties of the brittle deformation zones were calculated based on the equations of the Hoek-Brown failure criterion (Hoek et al. 2002).

The rock mass quality for brittle deformation zones is determined using the GSI value. The GSI value is calculated from the Q´ value. Q is derived from the Tunnelling Quality Index Q (Barton 2002):

∙ ∙ (4-1)

Name of Brittle deformation

zones

Intersects ONKALO tunnel at chainage

0–4990 m

Pre-core, core and post-core

mapped

Intersections in drillholes (number)

Confidence Scale

OL-BFZ011 2 Low RepositoryOL-BFZ016 1 Low RepositoryOL-BFZ019a ONK-BFI-93190-93600 13 + 1 (OL-PH4) High RepositoryOL-BFZ019c ONK-BFI-104500-110850 x 16 + 1 (OL-PH5) High RepositoryOL-BFZ020a ONK-BFI-3159 x 33 High Site scaleOL-BFZ020b ONK-BFI-3285 x 15 High Site scaleOL-BFZ021 13 High Site scaleOL-BFZ039 2 Low Repository

ONK-BFI-3540 4 + (OL-PH10,ONK-BFI-4276 OL-PH16,ONK-TDT-30-BFI-62.5 OL-PH17)

OL-BFZ099 19 High Site scaleONK-BFI-12850-12930ONK-BFI-52150-52300ONK-BFI-90020-90640ONK-BFI-159290-159500 xONK-BFI-181900-183100 xONK-BFI-248150-248200 xONK-BFI-293150-293750 x

OL-BFZ101 ONK-BFI-7000-7190 1 (OL-PH1) High RepositoryOL-BFZ106 4 Medium RepositoryOL-BFZ118 ONK-BFI-71310-71805 1 (OL-PH3) High RepositoryOL-BFZ146 11 High Site scaleOL-BFZ152 3 Medium Site scaleOL-BFZ160 1 Medium Site scaleOL-BFZ161 1 Medium Site scaleOL-BFZ175 7 High Site scaleOL-BFZ214 1 Medium Site scaleOL-BFZ-219 1 Low Repository

High Repository

OL-BFZ045b

ONK-BFI-136480-136600 ONK-BFI-223290-223450

OL-BFZ043 x 1

ONK-BFI-3350 ONK-BFI-4377 ONK-TDT-30-BFI-56.3

x1 + (OL-PH16,

OL-PH17)Low Repository

Ol-BFZ1008 + 2 (OL-PH1,

OL -PH4)High Site scale

OL-BFZ084x High Repository

70

, when parameters Jw and SRF are set to 1 Q = Q where

∙ (4-2)

The value of Q can be used to estimate the value of GSI:

9 ∙ ln 44 (4-3)

With high Q values, the GSI values calculated from equation (4-3) give values over 100. In these cases, the GSI is reduced to 100.

Ten of the analysed brittle fault zones intersect the ONKALO tunnel in the 0–4990 m tunnel chainage range. From seven of those zones, the pre core zones, core zones and post core zones have been mapped i.e. chainages less than the core zone, within the core zone and greater that the core zone, respectively (Figure 4-3). These zones are illustrated as well in the Figure 4-2; the black fault core indicates the core zone and the zones of influence indicate pre- and post core zones. The procedure for geotechnical mapping in the ONKALO access tunnel is described in Engström & Kemppainen (2008). From three of the zones, which intersect the ONKALO access tunnel, only the logged Q-median values of 5 meter long chainage sections are available. In these cases, drillhole data was used to classify the zones rock mass quality. Brittle deformation zones which are not intersected by the tunnel are also classified based on drillhole logging.

71

Figure 4-3. An example of geotechnical mapping of a deformation zone intersection in the ONKALO access tunnel.

ZONE INTERSECTIONDATA IMPORT

Site Tunnel IDONKALO VT1

24-2 transition 1:-10 120 17.9.2010 PJUH

From To Dip Dip dir.

4377.3 4384.6 86 92

4384.60 4389.0 89 80

4383,00 4387,00 86 84

4383,00 4387.0 86 84

Within the core zone

Within the damage zone

Dripping No Yes 4380_14380_6,4380_37,4380_38,4380_8,43

80_7,4385_47

Zone1 Footwall

Width (m)1,5

Ri-Class

RiIII

RQD Jn Jr Ja Jw SRF Q Q-quality90 3 1 2 1 5 3,000 Poor

Zone2 SIN

Width (m)

0,45

Ri-Class

RiIV-Rk4

RQD Jn Jr Ja Jw SRF Q Q-quality25 3 0,5 6 1 5 0,139 Very Poor

Zone3 Hanging wall

Width (m)1

Ri-Class

RiIII

RQD Jn Jr Ja Jw SRF Q Q-quality90 2 1 2 1 5 4,500 Fair

Tunnel dip

Chainage (m) Orientation (degrees)

ZONE start (tunnel PLfrom)Intersection type

Geologist

Zone position

4377BFI

Tunnel profile

Zone Intersection ID

ONK-VT1-BFI-4377

Increased fault-parallel fracturing with some wall-rock alteration (chloritization, illitization, saussuritization, pinitization). Same width on both sides.

Q-CLASSIFICATION

DescriptionIncreased fault-parallel fracturing with some wall-rock alteration (chloritization, illitization, saussuritization, pinitization). The pre-core zone is ~2 m wide on the left wall and 1.7 m wide on the right.

Q-CLASSIFICATION

Description

Description

The core of the zone consists of a layered, cohesive breccia cemented by quartz, chlorite and sulphides (sphalerite, pyrite, chalcopyrite). In places the hydrothermal fillings form a network of undeformed hydrothermal veins. Some sections around the veins and the fault also appear to be illitized. The breccia overprints an older, also layered fine-grained mylonite with stretched quartz grains. The youngest overprinting structures observed in the core are incohesive fractures (chloritic slickensides and calcite-filled fracturing mainly). In places a very thin (some centimeters or millimeters wide) fault gouge or clay is present. The apparent slip direction is sinistral with a striation in direction 07/169. Chalcopyrite disease can be seen in the sphalerite grains filling the voids between the euhedral quartz grains in the hydrothermally cemented core. The core is ~0.45 m wide on the right wall and on the left wall the core is ~.20 m. wide and branched. Resembles OL-BFZ100 by appearance and orientation.

Q-CLASSIFICATION

Characteristics of the "Post core zone, damage zone"

Water leakage

Characteristics of the "Pre core zone, damage zone"

Sketch SampleConnection to previously known

intersections / deformation zones

Fracture Code(s)

ONK-BFI-3350,OL-BFZ045B

Characteristics of the "Core zone"

Tunnel direction

Mapping date

right wall

roof

middle +1 m

left wall

Tunnel part

72

Depending on the available data, the GSI value for each brittle deformation zone has been interpreted via one of the following methods. In cases where the core has been determined from the ONKALO access tunnel, the GSI for the brittle fracture zone is obtained from the zone core. If the deformation zone intersects the tunnel in several locations, the lower quartile of the mapped core value is used to express the poorest rock quality.

The drillhole intersection locations of the zones were based on geological indications (Table 4-2). Problems associated with the influence of the drillhole location and orientation on the observed structure has been highlighted by Hudson et al. (2008). The problem is clearly presented in Figure 4-4. The smallest GSI values that were found in each intersection were selected from drillhole intersection depth ranges, although in the case of many drillhole intervals, it is typical that several possible fault cores may exist. The interpreted GSI value for the deformation zone is the lower quartile value of all selected GSI values (Figure 4-5). The width of the range was not taken into account.

Figure 4-4. (a) Influence of drillhole (shown in red) location and (b) drillhole orientation on the brittle deformation zone expression in a drillhole. Depending on both the location and orientation of the drillhole, the intersected expression of the zone will be different (Hudson et al. 2008).

73

Figure 4-5. Schematic figure of logged GSI value in one brittle deformation zone. Selected GSI value in each intersection coloured with red. Interpreted GSI for zone value would be 49 (Mönkkönen et al. 2012).

Both approaches are conservative because the width of the modelled zone is much wider than the actual intersections. A method of the weighted average (weighted by length) of intersections was also considered when interpreting GSI values. As sections of poor rock quality are quite narrow, however, or as in some cases, the cores consist of only one or two grain filled fractures, these poor rock quality sections “disappeared” among better rock qualities within the zone intersection. As a conclusion at this stage for rock mechanics modelling purposes, it was decided to characterize the brittle fault zones by the value of the weakest plane region existing in the zone.

Table 4-2 and Figure 4-6 present the geological intersections and interpreted GSI values for OL-BFZ100.

Table 4-2. Geological indications for the OL-BFZ100 intersections. Core m_from and core m_to are the depths of the selected GSI value of intersection in question.

Hole_id

Geological intersection

m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-PH1 151.64 154.32 26 152.38 152.62

ONK-PH4

27.10 30.57 70 28.76 29.6

OL-KR22 337.65 340.45 67 338.20 339.60

OL-KR23 372.5 373.02 67 372.50 373.02

OL-KR25 216.5 222.05 43 217.65 218.31

Ol-KR26 95.80 98.25 70 96.82 97.9

OL-KR28 170.21 178.30 62 172.60 173.20

OL-KR34 48.38 53.77 43 48.38 49.46

OL-KR37 56.23 57.5 47 56.19 56.71

OL-KR42 183.03 198.83 --- No data

ONKALO 128.50 129.30 RiIV ONK_BFI_12850-12930



ONKALO 1592.90 1595.00 40 ONK_BFI_159290_159500

ONKALO 1819.00 1831.00 43 ONK_BFI_181900_183100

ONKALO 2481.50 2482.00 56 ONK-BFI-248150-248200

ONKALO 2931.50 2937.50 46 ONK-BFI-293150-293750

74

Figure 4-6. The minimum GSI values and the width of the minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ100. The dashed line presents the interpreted GSI-value of the core (GSI =43).

4.3 Strength of the intact rock

The strength of the intact rock within brittle deformation zones has not been updated after data provided in 2013. Earlier data is described in the first parameterisation report (Kuula H. 2010). Based on previous measurements, a rough estimate of the intact rock strength of the brittle deformation zone core is 20% x 114 MPa = 22 MPa which is based on Schmidt hammer measurements conducted in the ONKALO access tunnel (Posiva 2009).

New schmidt hammer measurements were performed in order to obtain the ratio of the intact rock mass vs. BFZ. The fracture surface was sanded by sawing a rectangle shaped pit into the tunnel floor or the tunnel wall (Figure 4-7a). The measurements were taken along a 30 cm long line from a sanded fracture surface across the fault core (Figure 4-7b). Every measurement point consisted of ten impacts. Measurements were taken from both walls of the sawed pit. The results of the new Schmidt hammer measurements are illustrated from Figure 4-8 to Figure 4-12. Mattila (2012) has also executed Schmidt hammer measurements across the core of the zone HZ20, which is illustrated in Figure 4-13.

20

40

60

80

ON

K_B

FI_

1592

90_1

5950

0

ON

K_B

FI_

1819

00_1

8310

0

ON

K-B

FI-

2931

50-2

9375

0

ON

K-B

FI-

2481

50-2

4820

0

ON

K_B

FI_

1285

0_12

930

ON

K_B

FI_

5215

0_52

300

ON

K_B

FI_

9002

0_90

640

OL-

PH

1

OL-

KR

25

OL-

KR

34

OL-

KR

37

OL-

KR

28

ON

K-P

H4

OL-

KR

22

OL-

KR

23

OL-

KR

26

GS

I

0

0,5

1

1,5

2

2,5

3

co

re w

idth

GSI

width

75

Figure 4-7. Schmidt hammer measuring of fault core. (a) ~50 cm long pit is sawed into tunnel floor or wall. Black line is the fault core. (b) Top view of sawed pit. The red rings illustrate the measurement points.

The rock mass parameters defined from the new measurement results of a fracture core are higher when compared to earlier evaluations e.g. Posiva 2013. The measurement orientation also has an effect on the results – old Schmidt hammer measurements were done perpendicular to the BFZ core, but the new measurements were done along the core. A BFZ has a significantly, even 50 % weaker core zone according to the Schmidt hammer measurements. Uniaxial compressive strength measurements are not made for the core zone rocks.

Figure 4-8. Measured Schmidt hammer values of a cross-section of BFZ-45 in demonstration tunnel 2, point 1. Red and blue lines illustrate measurement results from both sides of the sawed pit. The dashed line is the fault core.

0

10

20

30

40

50

60

70

80

90

100

West 15 cm West 10 cm West 5 cm middle East 5 cm East 10 cm East 15 cm


mer

southern side

northern side

76

Figure 4-9. Measured Schmidt hammer values of a cross-section of BFZ-45 in demonstration tunnel 2, point 2. Red and blue lines illustrate measurement results from both sides of the sawed pit. The dashed line is the fault core..

Figure 4-10. Measured Schmidt hammer values of a cross-section of BFZ-297 in demonstration tunnel 2. Red and blue lines illustrate measurement results from both sides of the sawed pit. The dashed line is the fault core.

0

10

20

30

40

50

60

70

80

90

100

west 15 cm west 10 cm west 5 cm middle east 5 cm east 10 cm east 15 cm


mer

southern side

northern side

0

10

20

30

40

50

60

70

80

90

100

North 15 cm North 10 cm North 5 cm middle South 5 cm North 10 cm South 15 cm


mer

eastern side

western side

77

Figure 4-11. Measured Schmidt hammer values of a cross-section of BFZ-20A in ONKALO access tunnel in chainage 3160 m. Red and blue lines illustrate measurement results from both sides of the sawed pit. The dashed line is the fault core.

Figure 4-12. Measured Schmidt hammer values of a cross-section of a joint in the vicinity of BFZ-100 in ONKALO access tunnel in chainage 1815 m. Red and blue lines illustrate measurement results from both sides of the sawed pit. The dashed line is the joint core.

0

10

20

30

40

50

60

70

80

90

100

Up 15 cm Up 10 cm Up 5 cm middle Down 5 cm Down 10 cm Down 15 cm


mer

southwestern side

eastern side

0

10

20

30

40

50

60

70

80

90

100

west 15 cm west 10 cm west 5 cm middle east 5 cm east 10 cm east 15 cm


mer

upper part

central part

78

Figure 4-13. Measured Schmidt hammer values across HZ20 in the exhaust air shaft. The dashed line is the core of the fault zone. Data from Mattila (pers. comm. 2013).

4.4 Strength and deformability properties of brittle deformation zones

The strength and deformability properties of the brittle deformation zones were estimated via RocLab-software based on the equations of the Hoek-Brown failure criterion and the results are presented in Table 4-3.

The Hoek-Brown strength criterion can be expressed as (Hoek et al. 2002):

a

cibci sm

'

'' 331 (4-4)

where '1 and '3 are the major and minor effective principal stresses at failure, ci is the uniaxial compressive strength of the intact rock material.

mb is a reduced value of the material constant m

i and is given by

D

GSImm ib 1428

100exp (4-5)

s and a are constants for the rock mass given by the following relationships:

D

GSIs

39

100exp (4-6)

0

10

20

30

40

50

60

70

80

90

100


mer

distance from the core (m)

79

3/2015/

6

1

2

1 eea GSI (4-7)

GSI is a geological strength index. It is calculated from the Q value by using equation (4-3). D is a factor which depends upon the degree of disturbance to which the rock mass has been subjected to by blast damage and stress relaxation. It varies from 0 for undisturbed in situ rock masses to 1 for very disturbed rock masses.

The Mohr-Coulomb fit previously determined for parameterisation of brittle fault zones was made according to a normal stress of 28 MPa leading to lower angles of friction and higher joint cohesions (Kuula 2010). 28 MPa was at that time close to the average maximum horizontal stress at depth. This approach is acceptable as it is plausible to assume generally low friction angles and high normal stresses for large-scale geological features such as brittle fault zones which extend to significant depths. The current Mohr-Coulomb fit to the Hoek-Brown failure criterion was determined according to an approximate depth of -300 m leading to a normal stress of ca. 4 MPa. This defined lower joint cohesions and higher friction angles.

The Young’s moduli of brittle deformation zones (zone core) were estimated from seismic P-wave velocities measured from drillholes in order to base the data on measurements. The correlation between the Young’s Modulus (E) derived theoretically and from the seismic data is presented in Figure 4-14. The theoretical Young’s Modulus is defined using the GSI of a zone combined with the previously defined intact rock mass parameters. The Young’s modulus was calculated from each drillhole intersection, where data was available, with equation 4-8 (Barton 2002). The distances between the transmitter and the receiver when measuring seismic velocities, were 0.6 m or 1.0 m depending on the available data. If 0.6 transmitter-receiver distance data was not available, data measured with a 1.0 m transmitter-receiver distance was used. Data measured with 0.6 m transmitter-receiver distance was available from drillholes OL-KR29 – OL-KR40B, OL-KR42 – OL-KR57 and ONK-PH4. Data measured with a 1.0 m transmitter-receiver distance was available from drillholes OL-KR1 –OL-KR28. This technique enables the detection of fault cores with a minimum width of 5 - 15 cm as distinct velocity anomilies, although background noise causes noticeable degradation in anomaly clarity. True seismic wave velocities can therefore only be measured from zones with a width of at least 0.6 m or 1 m depending on the technique in use.

)3/)5.3((1010 PVE (4-8)

80

Figure 4-14. The correlation of the theoretical Young’s Modulus (E) and the modulus derived from seismic data. Correlation 0.5178/1.

0

10

20

30

40

50

60E (Gpa)

seismic data

theoretical

Moving Average (seismic data)

Moving Average (theoretical)

81

The determined Young’s modulus for each brittle deformation zone is the lower quartile of calculated Young’s modulus values from all drillhole intersections (core from – core to) of each brittle deformation zone in question. The average value of the determined Young’s moduli for the brittle deformation zones is 28.6 GPa. This value is applied for those brittle deformation zones from which no seismic data is available (OL-BFZ045b, OO-BFZ101, OL-BFZ118 and OL-BFZ214). The results are presented Table 4-3. The drillhole intersections and calculated lower quartile, median value and upper quartile for each brittle deformation zone are presented in Appendix 2. In the previous report analysed Brittle deformation zone (BFZ-159) has been removed due to a changed geometry and the removal of the only drillhole intersection, although it was included in the analysis in the previous report.

Table 4-3. Strength and deformability properties of brittle deformation zones.

OL-BFZ011 OL-BFZ016 OL-BFZ019a OL-BFZ019c OL-BFZ020a OL-BFZ020bBFZ characteristics

Core width ‐ ‐ ‐ 0.2 0.1 2

Rock mass quality (GSI) 51 49 59 64 54 50

mapped core mapped core mapped core

1st quartile of 1st quartile of value from value from value from

drillhole drillhole drillhole tunnel tunnel tunnel

intersections intersection intersections intersection intersection intersection

Strength of intact parts

sigci (Mpa) 22 22 22 22 22 22

mi 10 10 10 10 10 10

D 0 0 0 0 0 0

Strength of BFZ

Hoek Brown Criterion

mb 1.74 1.62 2.31 2.76 1.93 1.68

s 0.0043 0.0035 0.0105 0.0183 0.0060 0.0039

a 0.51 0.51 0.50 0.50 0.50 0.51

Mohr‐Coulomb Fit

cohesion (Mpa) 0.9 0.8 1.0 1.1 0.9 0.8

friction angle (°) 34 34 36 38 35 34

tensile strength (Mpa) 0.05 0.05 0.10 0.15 0.07 0.05

compressive strength (Mpa) 1.40 1.2 2.2 3.0 1.7 1.3

Deformability of BFZ

Young's Modulus (Gpa) 24.5 29.4 14.6 27.5 22.6 20.5

G = E / 2(1+n), n = 0.25 (Gpa) 9.8 11.8 5.8 11.0 9.04 8.2

Equivalent Stiffness of BFZ*

Kn = E / width (Gpa/m) ‐ ‐ ‐ 137.5 226 10.25

Ks = G / width (Gpa/m) ‐ ‐ ‐ 55 90.4 4.1* Due to variation of the width of the zone core in drillcore intersections,stiffness parameters have been determined only for zones which intersect the tunnel (minimum width used)

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OL-BFZ021 OL-BFZ039 OL-BFZ043 OL-BFZ045b OL-BFZ084 OL-BFZ099BFZ characteristics

Core width ‐ ‐ 0.15‐1.6 0.4 0.2 ‐


mapped core mapped core mapped core

1st quartile of value from value from value from 1st quartile of

drillhole drillhole tunnel tunnel tunnel drillhole

intersections intersection intersections intersections intersections intersections


sigci (Mpa) 22 22 22 22 22 22

mi 10 10 10 10 10 10

D 0 0 0 0 0 0

Strength of BFZ


mb 1.22 2.39 2.87 1.31 1.51 1.22

s 0.0014 0.0117 0.0205 0.0018 0.0028 0.0014

a 0.51 0.50 0.50 0.51 0.51 0.51

Mohr‐Coulomb Fit

cohesion (Mpa) 0.7 1.0 1.1 0.7 0.8 0.7

friction angle (°) 31 37 38 32 33 31




Young's Modulus (Gpa) 18.6 35.9 56.9 28.6** 27.4 14.4

G = E / 2(1+n), n = 0.25 (Gpa) 7.44 14.4 22.8 11.44 10.9 5.76


Kn = E / width (Gpa/m) ‐ ‐ 379.3 71.5 137 ‐

Ks = G / width (Gpa/m) ‐ ‐ 152.0 28.6 54.5 ‐* Due to variation of the width of the zone core in drillcore intersections,stiffness parameters have been determined only for zones which intersect the tunnel (minimum width used)** No seismic data available, average value of all brittle deformation zones

OL-BFZ100 OL-BFZ101 OL-BFZ106 OL-BFZ118 OL-BFZ146 OL-BFZ152BFZ characteristics

Core width 0.25‐1 ‐ ‐ ‐ ‐ ‐


mapped core

value from 1st quartile of 1st quartile of 1st quartile of

tunnel drillhole drillhole drillhole drillhole drillhole

intersections intersection intersections intersection intersections intersections


sigci (Mpa) 22 22 22 22 22 22

mi 10 10 10 10 10 10

D 0 0 0 0 0 0

Strength of BFZ


mb 1.30 1.40 0.74 2.39 1.62 2.57

s 0.0018 0.0022 0.0003 0.0117 0.0035 0.0147

a 0.51 0.51 0.53 0.50 0.51 0.50

Mohr‐Coulomb Fit

cohesion (Mpa) 0.7 0.8 0.5 1.0 0.8 1.1

friction angle (°) 32 33 27 37 34 37




Young's Modulus (Gpa) 32 28.6** 19.9 28.6** 17.8 43

G = E / 2(1+n), n = 0.25 (Gpa) 12.8 11.44 7.96 11.44 7.12 17.2


Kn = E / width (Gpa/m) 128.0 ‐ ‐ ‐ ‐ ‐

Ks = G / width (Gpa/m) 51.2 ‐ ‐ ‐ ‐ ‐* Due to variation of the width of the zone core in drillcore intersections,stiffness parameters have been determined only for zones which intersect the tunnel (minimum width used)** No seismic data available, average value of all brittle deformation zones

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OL-BFZ160 OL-BFZ161 OL-BFZ175 OL-BFZ214 OL-BFZ219BFZ characteristics

Core width ‐ ‐ ‐ ‐ ‐

Rock mass quality (GSI) 46 65 48 40 51

1st quartile of

drillhole drillhole drillhole drillhole drillhole

intersection intersection intersections intersection intersection


sigci (Mpa) 22 22 22 22 22

mi 10 10 10 10 10

D 0 0 0 0 0

Strength of BFZ


mb 1.45 2.87 1.56 1.17 1.74

s 0.0025 0.0205 0.0031 0.0013 0.0043

a 0.51 0.50 0.51 0.51 0.51

Mohr‐Coulomb Fit

cohesion (Mpa) 0.8 1.1 0.8 0.7 0.9

friction angle (°) 33 38 33 31 34

tensile strength (Mpa) 0.04 0.16 0.04 0.02 0.05

compressive strength (Mpa) 1.0 3.1 1.2 0.7 1.4


Young's Modulus (Gpa) 37.4 39.8 33.4 28.6** 28.1

G = E / 2(1+n), n = 0.25 (Gpa) 14.9 15.9 13.36 11.44 11.2


Kn = E / width (Gpa/m) ‐ ‐ ‐ ‐ ‐

Ks = G / width (Gpa/m) ‐ ‐ ‐ ‐ ‐* Due to variation of the width of the zone core in drillcore intersections,stiffness parameters have been determined only for zones which intersect the tunnel (minimum width used)** No seismic data available, average value of all brittle deformation zones

84

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5 CONCLUSIONS AND RECOMMENDATIONS

In this report, the geometrical and mechanical parameters of fractures and brittle deformation zones in the vicinity of the ONKALO volume have been estimated for the tunnel chainage range 4390–4990 m. This report is an extension of two previously published reports: Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones Based on the ONKALO Tunnel Mapping, 0–2400 m Tunnel Chainage (Kuula 2010) and Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones Based on the ONKALO Tunnel Mapping, 2400–4390 m Tunnel Chainage (Mönkkönen et al. 2012). At this stage, the main target of the work is to obtain preliminary parameters for rock mechanics simulations and rock mechanics design.

Five major fracture sets can be identified from the ONKALO tunnel mapping data from a tunnel chainage of 4390–4990 m. The set windows have been updated for the last ONKALO access tunnel section and technical rooms levels on account of the changed fracture orientation. The deepest levels of ONKALO contain fractures that fall into the previous sets A and C and into the new sets B2, C2 and D.

In the ONKALO access tunnel vertical set A, 89°/262°, is commonly observed in an access tunnel range of 4390–4990 m, except between 4855–4884 m. On closer inspection, it is noted that the amount of Set A fractures remains fairly constant with increasing depth. At the demonstration tunnel level, Set A fractures are observed in both demonstration tunnels 1 and 2 and they become more frequent with increasing chainage values. At the level of the technical rooms Set A fractures become more common westwards in the parking hall and in the tech tunnels in the vicinity of the western part of the parking hall. Set A fractures are also observed at -457 level, although their amount is insignificant.

Gently dipping fracture set B2, 26°/342° is clearly observed in chainage range 4665–4756 m where the brittle fault zone BFZ-300 intersects the ONKALO access tunnel. Set B2 fractures are not observed at the demonstration tunnel level. At the level of the technical rooms the Set B2 is the most prominent fracture set in the tech parking hall. Set B2 is also the most common fracture set at -457 station level.

Vertical fracture set C, 89°/338°, is uncommon. Fracture set C is most frequently observed in the ONKALO access tunnel between 4470–4565 m, whereas the rest of the access tunnel has a clear absence of Set C fractures with only occasional Set C fractures. A negligible amount of Set C fractures is observed at the demonstration tunnel and -457 levels. At the level of the technical rooms Set C fractures exist especially in the parking hall, where the distribution is prevalent.

Sub-vertical fracture set C2, 61°/335°, is observed regularly in the ONKALO access tunnel due to a fairly constant fracture distribution except in chainage range 4470–4532 m. Set C2 is also observed at the demonstration tunnel level, although to a lesser degree.

Fracture Set D, 52°/181°, is observed only at the demonstration tunnel level. The concentration apparent in the demonstration tunnels and the perpendicular tech tunnel is due to the BFZ-297 intersection.

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The number of fracture sets varies with according to the tunnel chainage. Over the first 300 m chainage, the Jn median is 6. From chainage 300 m to approximately 1200 m, the Jn median is 3 and after chainage 1200 m, the Jn median drops to 1. The Jn median is 2 from 2400 m to the end of the access tunnel. The mean RQD value in the ONKALO tunnel from chainage 0 to 4990 m is 97%. From chainage 1200 m, the fracture intensity starts to decrease and the mean RQD value in chainage range 1200–4390 m is 98.4% compared to the mean value in the chainage range 0–1200 m of 94%. The last tunnel section does not include very low RQD values; the only significantly low RQD value (50 %) in the access tunnel is estimated at chainage 4383 m. The demonstration tunnels also contain significantly low RQD values such as 20 %. There are no notably low RQD values at the technical rooms and -457 levels.

Fractures mainly become longer with increasing depth, although the shortest fractures exist in the second tunnel section and not near the surface. Most of the short fractures end in rock and the long fractures continue beyond the tunnel. The fracture end type distribution seems to become more uniform with increasing depth.

In tunnel mapping data the fractures become smoother and more planar with increasing depth, the mean Jr value drops from 3 to 1.5. Only the amount of long slickensided fractures decreases with depth. The mean amount of slickensided fractures is less than 10%. The same trend is also apparent in drillhole data – the mean Jr value drops from 3 to 2 when comparing fractures before and after depth level -250 m.

The fracture end-type does not appear to correlate with roughness. The Jr value distribution at the levels of the technical rooms resembles the distribution observed in the access tunnel between chainages 1200–4990 m. Only at the demonstration tunnel level does Set D contain clearly rougher fractures; under a third of its fractures have a Jr between 1–1.5.

For chainages 0–1200 m, the mean Ja value is about 4. For very short fractures (length 1 m or less), the mean Ja value is 1. Between chainages 1200–4390 m fractures are less altered – the mean Ja value for fractures with lengths in a range of 0 to 5 m is 1. For longer fractures (20 m), the Ja value varies mainly between 2 to 3. In the deepest part of the access tunnel between chainages 4390–4990 m the Ja value varies mainly between 1–3 without any significant variation between short and long fractures. The amount of long and mineral filled fractures also decreases with depth at the levels of the technical rooms. Strongly altered fractures are clearly reduced at the deepest, -457 level. Correlation between joint alteration and depth was not apparent in drillcore mapping data.

Compared to other fracture sets between chainage 0–2400 m, set 4 has more altered fracture surfaces. Between chainages 2400–4390 m the joint alteration of Set A and Set C fractures resembles each other: more than half of the fractures in both sets are unaltered or slightly altered fractures with a Ja value 0.75 or 1, whereas Set B fractures are more often mineral-filled fractures. Fracture sets A, B2, C and C2 mainly have fractures with a Ja under 2, whereas Set D which is only observed at the demonstration tunnel level observed has higher Ja values due to softening or low friction clay minerals and thin or thick mineral fillings.

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The most common fracture fillings minerals are calcite, kaolinite, pyrite and chlorite. The proportion of calcite stays constant at all depths but the amount of kaolinite, pyrite and chlorite decreases remarkably with increasing depth.

In the first section, chainage range from 0 to 1200 m, the friction angle is mainly between 30° - 40° but the distribution is fairly uniform. In the second section of the tunnel (chainage 1200 to 2400 m), the friction angle increases for almost all fracture lengths, being mainly between 40°– 60°. As depth increases from 2400 to the end of the access tunnel, the friction angle value is 50°– 60° for short fractures (<5 meters) and 20°– 30° for longer fractures.

Fracture undulation varies the most according to fracture length between the first and second part of the access tunnel. Between chainages 0–1200 m the undulation is mainly 20–50 mm where the shortest fractures are the most planar. The principal difference between this part and deeper sections concerns fractures with a length over 20 m; their mean undulation increases from 0 mm to 20–50 mm. Between chainages 2400–4390 m the undulation varies almost linearly from 0 mm (fractures < 1 m) to 20–25 mm (fractures > 20 m). In the deepest parts of the ONKALO the fracture length shortens and the amount of undulation decreases slightly.

Estimation of the mechanical properties of the brittle deformation zones is based on Olkiluoto area drillholes and the ONKALO tunnel mapping. In this report, 23 fracture zones have been analysed.

Analysed brittle deformation zones have been selected based on their size and location and available data: a direct geological observation of deformation zone must exist i.e. deformation zone must intersect drillhole or ONKALO access tunnel so that any parameter can be estimated. All brittle deformation zones which are classified as site scaled zone and which fulfil the criterion of direct geological observation were analysed. Also repository scaled zones which are included in stress modelling (Valli et al. 2011) are analysed. These are mainly shallow dip zones which are located central or close to ONKALO and the repository. One of the main BDZ zones is OL-BFZ100 which intersects the tunnel in several places. Compared to the previous parameterisation report the parameters of some brittle deformation zones have changed due to changed fracture zone geometries and new drillhole and tunnel intersections.

The cohesion of the brittle deformation zones varies between 0.6–1.1 MPa and the friction angle between 28°–38°. The Mohr-Coulomb fit previously determined for parameterisation of brittle fault zones was done according to a normal stress of 28 MPa leading to lower angles of friction and higher joint cohesions (Kuula 2010). 28 MPa was at that time close to the average maximum horizontal stress at depth. This approach is acceptable as it is plausible to assume generally low friction angles and high normal stresses for large-scale geological features such as brittle fault zones which extend to significant depths. The current Mohr-Coulomb fit to the Hoek-Brown failure criterion was determined according to an approximate depth of -300 m leading to a normal stress of ca. 4 MPa. This defined lower joint cohesions and higher friction angles.

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The Young’s modulus of brittle fault zones varies between 14.4–56.9 GPa and the uniaxial compressive strength between 0.31–3.12 MPa. The average Young’s modulus value is 28.6 GPa.

Direct shear tests results are missing from vertical major fracture sets and filled moderately dipping fractures. The laboratory tests recommended in the previous parameterisation report for joint normal and shear stiffness analysis are presently in progress.

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REFERENCES

Aaltonen, I., (ed.), Lahti, M., Engström, J., Mattila, J., Paananen, M., Paulamäki, S., Gehör, S., Kärki, A., Ahokas, T., Torvela, T. & Front, K. 2010. Geological Model of the Olkiluoto Site - Version 2.0. Working Report 2010-70. Posiva Oy, Eurajoki.

Aydin, A. 2008. ISRM Suggested method for determination of the Schmidt hammer rebound hardness: Revised version. International Journal of Rock Mechanics & Mining Sciences 46, p. 627–634.

Aydin, A. & Basu, A. 2005. The Schmidt hammer in rock material characterization. Engineering geology 81, 1–14.

Barton, N. 2002. Some new Q-value correlations to assist in site characterisation and tunnel design. International Journal of Rock Mechanics and Mining Sciences 39 (2002), 185–216.

Barton, N.R. & Bandis, S.C. 1990. Review of predictive capabilites of JRC-JCS model in engineering practice. In Rock joints, proc. int. symp. on rock joints, Loen, Norway, (eds N. Barton and O. Stephansson), 603–610. Rotterdam: Balkema.

Deere, D.U., Hendron, A.J., Patton, F.D. & Cording, E.J. 1967. Design of surface and near surface construction in rock. In Failure and breakage of rock, proc. 8th U.S. symp. rock mech., (ed. C. Fairhurst), 237–302. New York: Soc. Min. Engrs, Am. Inst. Min. Metall. Petrolm Engrs.

Engström, J. & Kemppainen, K. 2008. Evaluation of the geological and geotechnical mapping procedures in use in the ONKALO access tunnel. Posiva Oy, Working Report 2008–77.

Hoek, E. 2007. Practical rock engineering. URL: http://www.rocscience.com/hoek/PracticalRockEngineering.asp course notes

Hoek, E., Carranza-Torres, C. T. & Corkum, B. 2002. Hoek-Brown failure criterion – 2002 edition. Proc. North American Rock Mechanics Society meeting in Toronto in July 2002.

Hudson, J. A., Cosgrove, J. & Johansson, E. 2008. Estimating the mechanical properties of the brittle deformation zones at Olkiluoto. Working Report 2008–67. Posiva Oy, Eurajoki.

Kuula, H. 2010. Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones based on ONKALO Tunnel Mapping, 0–2400 m Tunnel Chainages. Working Report 2010-64. Posiva Oy, Eurajoki.

Mattila, J., Aaltonen, I., Kemppainen, K. Wikström, L., Paananen, M., Paulamäki, S., Front, K. Gehör, S., Kärki, A. & Ahokas, T. 2008. Geological model of the Olkiluoto Site. Version 1.0. Working Report 2007-92. Posiva Oy, Eurajoki.

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Mönkkönen, H., Rantanen, T. & Kuula, H. 2012. Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones based on ONKALO Tunnel Mapping, 2400–4390 m Tunnel Chainages. Working Report 2010-64. Posiva Oy, Eurajoki.

Nordbäck, N. 2013. Outcome of the Geological Mapping of the ONKALO Underground Research Facility Access Tunnel, Chainage 3116–4986. Geological Survey of Finland, Working Report 2013-11.

Nordbäck, N., Engström, J. & Kemppainen, K. 2008. Outcome of the Geological Mapping of the ONKALO Underground Research Facility Access Tunnel, Chainage 0-990. Posiva Oy, Working Report 2008-84.

Nordbäck, N. & Engström, J. 2010. Outcome of the Geological Mapping of the ONKALO Underground Research Facility Access Tunnel, Chainage 990–1980. Posiva Oy, Working Report 2010-41.

Nordbäck, N., 2010. Outcome of the the geological mapping of the ONKALO underground research facility access tunnel, chainage 1980–3116. Working Report 2010-42. Posiva Oy, Eurajoki.

Palmström, A. 1982. The volumetric joint count - a useful and simple measure of the degree of rock jointing. Proc. 4th congr. Int. Assn Engng Geol., Delhi 5, 221–228.

Posiva 2013. Olkiluoto Site Description 2011, Posiva Report 2011-02.

Posiva 2009. Olkiluoto Site Description 2008, Posiva Report 2009-01.

Terzaghi, R. D. (1965). Sources of error in joint surveys. Geotechnique 15: 287–304.

Valli, J., Hakala, M., & Kuula, H. 2011 Modelling of the in-situ stress state at Olkiluoto. Working Report 2011-34. Posiva Oy, Eurajoki.

Valli, J. 2010. Investigation Ahead of the Tunnel Face by use of a Measurement-While-Drilling System at Olkiluoto, Finland. Master’s Thesis. University of Turku.

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APPENDICES

The following three Appendices provide further supporting information to the main body of the Report with regard to the Q parameters, more fracture geometry detail, GSI BDZ information, information for the location of technical rooms and the details of the Hoek-Brown failure criterion.

APPENDIX 1 Classification of individual parameters used in the Tunnelling Quality Index Q

APPENDIX 2 Geological indications, the GSI values and Young’s modulus for the Brittle Deformation Zones

APPENDIX 3 Analysed technical rooms levels

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APPENDIX 1 Classification of individual parameters used in the Tunnelling Quality Index Q (Barton 2002).

1 RQD (Rock Quality Designation) RQD

A Very poor 0-25

B Poor 25-50

C Fair 50-75

D Good 75-90

E Excellent 90-100

Note: i) Where RQD is reported or measured as ≤ 10 (including 0) the nominal value 10

is used to evaluate the Q-value

ii) RQD intervals of 5, i.e., 100, 95, 90, etc., are sufficiently accurate

2 Joint set number Jn

A Massive, no or few joints 0.5-1

B One joint set 2

C One joint set plus random joints 3

D Two joint sets 4

E Two joint sets plus random joints 6

F Three joint sets 9

G Three joint sets plus random joints 12

H Four or more joint sets, random, heavily jointed, .sugar-cube., etc. 15

J Crushed rock, earthlike 20

Notes: i) For tunnel intersections, use (3.0 × Jn ).

ii) For portals use (2.0 × Jn ).

3 Joint roughness number Jr

a) Rock-wall contact, and b) Rock-wall contact before 10 cm shear

A Discontinuous joints 4

B Rough or irregular, undulating 3

C Smooth, undulating 2

D Slickensided, undulating 1.5

E Rough or irregular, planar 1.5

F Smooth, planar 1.0

G Slickensided, planar 0.5

Notes: i) Descriptions refer to small-scale features and intermediate scale features, in that order.

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b) No rock-wall contact when sheared

H Zone containing clay minerals thick enough to prevent rock-wall contact.

1.0

J Sandy, gravely or crushed zone thick enough to prevent rock-wall contact

1.0

Notes: ii) Add 1.0 if the mean spacing of the relevant joint set is greater than 3 m. iii) Jr = 0.5 can be used for planar, slickensided joints having lineations, provided the lineations are oriented for

minimum strength. iv) Jr and Ja classification is applied to the joint set or discontinuity that is least favourable for stability both

from the point of view of orientation and shear resistance, (where ≈ σn tan-1 (Jr /Ja ).

4 Joint alteration number r

approx. Ja

a) Rock-wall contact (no mineral fillings, only coatings)

A Tightly healed, hard, non-softening, impermeable filling, i.e., quartz or epidote.

-- 0.75

B Unaltered joint walls, surface staining only. 25-35° 1.0

C Slightly altered joint walls. Non-softening mineral coatings, sandy particles, clay-free disintegrated rock, etc. 25-30° 2.0

D Silty- or sandy-clay coatings, small clay fraction (non-softening).

20-25° 3.0

E Softening or low friction clay mineral coatings, i.e., kaolinite or mica. Also chlorite, talc, gypsum, graphite, etc., and small quantities of swelling clays.

8-16° 4.0

b) Rock-wall contact before 10 cm shear (thin mineral fillings)

F Sandy particles, clay-free disintegrated rock, etc. 25-30° 4.0

G Strongly over-consolidated non-softening clay mineral fillings (continuous, but < 5 mm thickness).

16-24° 6.0

H Medium or low over-consolidation, softening, clay mineral fillings (continuous, but < 5 mm thickness).

12-16° 8.0

J Swelling-clay fillings, i.e., montmorillonite (continuous, but < 5 mm thickness). Value of Ja depends on per cent of swelling clay-size particles, and access to water, etc.

6-12° 8-12

c) No rock-wall contact when sheared (thick mineral fillings)

KL M

Zones or bands of disintegrated or crushed rock and clay (see G, H, J for description of clay condition).

6-24° 6, 8, or 8-12

N Zones or bands of silty- or sandy-clay, small clay fraction (non-softening).

-- 5.0

OP R

Thick, continuous zones or bands of clay (see G, H, J for description of clay condition).

6-24° 10, 13,

or 13-20

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5 Joint water reduction factor approx. water

pres. (kg/cm2) Jw

A Dry excavations or minor inflow, i.e., < 5 l/min locally.

< 1 1.0

B Medium inflow or pressure, occasional outwash of joint fillings.

1-2.5 0.66

C Large inflow or high pressure in competent rock with unfilled joints.

2.5-10 0.5

D Large inflow or high pressure, considerable outwash of joint fillings.

2.5-10 0.33

E Exceptionally high inflow or water pressure at blasting, decaying with time.

> 10 0.2-0.1

F Exceptionally high inflow or water pressure continuing without noticeable decay.

> 10 0.1-0.05

Notes: i) Factors C to F are crude estimates. Increase Jw if drainage measures are installed.

ii) Special problems caused by ice formation are not considered.

iii) For general characterization of rock masses distant from excavation influences, the use of Jw = 1.0, 0.66,

0.5, 0.33 etc. as depth increases from say 0-5m, 5-25m, 25-250m to >250m is recommended, assuming

that RQD /Jn is low enough (e.g. 0.5-25) for good hydraulic connectivity. This will help to adjust Q for some

of the effective stress and water softening effects, in combination with appropriate characterization values of

SRF. Correlations with depth-dependent static deformation modulus and seismic velocity will then follow the

practice used when these were developed.

6 Stress Reduction Factor SRF

a) Weakness zones intersecting excavation, which may cause loosening of rock mass when tunnel is excavated

A Multiple occurrences of weakness zones containing clay or chemically disintegrated rock, very loose surrounding rock (any depth).

10

B Single weakness zones containing clay or chemically disintegrated rock (depth of excavation ≤ 50 m).

5

C Single weakness zones containing clay or chemically disintegrated rock (depth of excavation > 50 m).

2.5

D Multiple shear zones in competent rock (clay-free), loose surrounding rock (any depth).

7.5

E Single shear zones in competent rock (clay-free), (depth of excavation ≤ 50 m).

5.0

F Single shear zones in competent rock (clay-free), (depth of excavation > 50 m).

2.5

G Loose, open joints, heavily jointed or .sugar cube., etc. (any depth) 5.0

Notes: i) Reduce these values of SRF by 25-50% if the relevant shear zones only influence but do not intersect the

excavation. This will also be relevant for characterization.

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b) Competent rock, rock stress problems σc /σ1 σθ /σc SRF

H Low stress, near surface, open joints. > 200 < 0.01 2.5

J Medium stress, favourable stress condition. 200-10 0.01-0.3 1

K High stress, very tight structure. Usually favourable to stability, may be unfavourable for wall stability.

10-5 0.3-0.4 0.5-2

L Moderate slabbing after > 1 hour in massive rock. 5-3 0.5-0.65 5-50

M Slabbing and rock burst after a few minutes in massive rock.

3-2 0.65-1 50-200

N Heavy rock burst (strain-burst) and immediate dynamic deformations in massive rock.

< 2 > 1 200-400

Notes: ii) For strongly anisotropic virgin stress field (if measured): When 5 ≤ σ1 / σ3 ≤ 10, reduce σc to 0.75 σc. When

σ1 / σ3 > 10, reduce σc to 0.5 σc, where σc = unconfined compression strength, σ1 and σ3 are the major

and minor principal stresses, and σθ = maximum tangential stress (estimated from elastic theory).

iii) Few case records available where depth of crown below surface is less than span width. Suggest an SRF

increase from 2.5 to 5 for such cases (see H).

iv) Cases L, M, and N are usually most relevant for support design of deep tunnel excavations in hard massive

rock masses, with RQD /Jn ratios from about 50 to 200.

v) For general characterization of rock masses distant from excavation influences, the use of SRF = 5, 2.5,

1.0, and 0.5 is recommended as depth increases from say 0-5m, 5-25m, 25-250m to >250m. This will help

to adjust Q for some of the effective stress effects, in combination with appropriate characterization values

of Jw. Correlations with depth - dependent static deformation modulus and seismic velocity will then follow

the practice used when these were developed.

c) Squeezing rock: plastic flow of incompetent rock under the influence of high rock pressure

σθ /σc SRF

O Mild squeezing rock pressure 1-5 5-10

P Heavy squeezing rock pressure > 5 10-20

Notes: vi) Cases of squeezing rock may occur for depth H > 350 Q1/3 according to Singh 1993. Rock mass

compression strength can be estimated from SIGMAcm ≈ 5 Qc1/3 (MPa) where = rock density in t /m3, and

Qc=Qx c /100, Barton, 2000.

d) Swelling rock: chemical swelling activity depending on presence of water

SRF

R Mild swelling rock pressure 5-10

S Heavy swelling rock pressure 10-15

97

APPENDIX 2. Geological descriptions, the GSI values and Young’s modulus for the Brittle Deformation Zones

OL- BFZ-011

Figure A2 - 1. Brittle deformation zone OL- BFZ-011.

The interpreted GSI value for OL-BFZ011 is 51 and interpreted Young’s modulus is 24.5 GPa. Geological description of OL-BFZ011 is following (Aaltonen et al. 2010):

VGN and a cross-cutting narrow pegmatite. Fractured, slickensides, sulphide-fillings and porosity. Fractures are quite parallel. No open fracture resistivity.

OL_KR40_BFI_49896_50066: The intersection locates in VGN - DGN, and consists of 10 fractures of which 4 are slickensided and with chlorite, pyrite and clay-filled. The non-slickensided fractures are also chlorite/clay filled and occasionally show small signs of movement. The core of the intersection is poorly defined at 499.45 - 499.80 m and consists of three slickenside fractures. The lineations show a shallow dip to direction 215 degrees. The rock contains small amounts of pyrrhotite. At the end of the section there is a very narrow SFI.

Table A2 - 1. Intersections OL-BFZ011 at drill cores. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view

Geological intersection Geological intersection Core Core Core

m_from m_to GSI m_from m_to

OL-KR9 147.33 149.56 49 149 149.3

OL-KR40 520.3 520.97 59 520.3 520.97

Hole_id

98

Figure A2 - 2. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ011. The interpreted GSI-value of the deformation zone core is 51.

Table A2 - 2. Lower quartile, median value and upper quartile of Young’s modulus calculated from seismic P-wave velocities.

Lower quartile (GPa) Median (GPa) Upper quartile (GPa)

24.5 47.3 49.0

Table A2 - 3. Intersections OL-BFZ011 at drill cores. Young’s modulus is calculated from data between depths Core m_from and core m_to.

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-KR9 OL-KR40

GSIwidth

Geological intersection Geological intersection Core Core Distance btw

m_from m_to m_from m_to transm and recvr

OL-KR9 147.33 149.56 149 149.3 1

OL-KR40 520.3 520.97 520.3 521 0.6

Hole_id

99

OL-BFZ016

Figure A2 - 3. Brittle deformation zone OL-BFZ016.


The fault is within the diatexitic gneiss (DGN), with some short sections of mafic gneiss (MFGN). Old and welded fractures where calcite is present. These old fractures have partly been reactivated later. The intersection contains 50 joints. The rock is most fractured in section 379.18-379.80, containing 18 fractures Dip directions of the fractures are towards the NNW, with moderate to steep dip. Numerous slickenside surfaces with a NE-SW striation trend. The movement on surfaces is random.

Table A2 - 4. Intersections OL-BFZ016 at drill cores. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.

Hole_id Geological intersection

m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR8 376.00 383.00 49 379.2 379.8

100

Figure A2 - 4. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ016. The Interpreted GSI-value of the deformation zone core is 49.



29.4 30.2 30.6

Table A2 - 6. Intersection OL-BFZ016 at drill core. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR8 376.00 383.00 379.20 379.80 1.0

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-KR8

GSIwidth

101

OL-BFZ019a

Figure A2 - 5. Brittle deformation zone OL-BFZ019a

The interpreted GSI value for OL-BFZ019a is 59 and interpreted Young’s modulus is 14.6 GPa. Geological description of OL-BFZ019a is following (Aaltonen et al. 2010):

OL-BFZ019a is a gently dipping thrust fault with an approximate dip of c. 15 degrees towards the SE. The thickness of the fault core varies from 0.1 to 4 m. The fault is located a few tens of meters above fault OL-BFZ019c and is subparallel to it. Predominantly fracture-controlled kaolinisation, illitisation and sulphidisation are observed along the zone, although sporadically the alteration is also pervasive. As a result of re-examination of the geological data, the lateral extent of the fault is limited only to the ONKALO area in the current model. The core is characterized mainly by RiIII-IV-sections according to the RG-classification and the core of the fault is also hydraulically conducting in most of the drillhole intersections.

102

Table A2 - 7. Intersections OL-BFZ019a at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR4 81.50 82.40 69 81.50 82.40

OL-KR7 26.00 42.55 67 36.16 37.39

OL-KR22 138.80 146.05 72 144.9 145.6

OL-KR24 94.02 94.35 49 92.02 94.35

OL-KR25 94.45 97.30 62 96.09 96.73

OL-KR28 154.50 155.50 71 154.50 155.50

OL-KR30 52.22 53.88 69 52.20 53.88

OL-KR34 78.32 78.83 52 78.30 78.80

OL-KR35 90.00 96.00 64 94.40 94.60

OL-KR36 153.60 156.80 61 154.77 155.90

OL-KR37 123.32 123.83 73 123.30 123.80

OL-KR38 88.10 88.75 57 88.10 88.70

OL-KR48 93.90 101.00 60 96.10 96.39

ONK-PH4 84.00 85.53 40 85.53 85.68 CL 15cm

ONKALO 931.90 963.00 62 932.80 937.90 Q_median

Figure A2 - 6. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ019a. The interpreted GSI-value of the deformation zone core is 59.

GS

I

core

wid

th

20 0

40 2

60 4

80 6

OL-

KR

24

OL-

KR

34

OL-

KR

38

OL-

KR

48

OL-

KR

36

OL-

KR

25

OL-

KR

35

OL-

KR

7

OL-

KR

4

OL-

KR

30

OL-

KR

28

OL-

KR

22

OL-

KR

37

ON

K-P

H4

ON

K-B

FI-

9319

0-96

300

GSIwidth

103



14.6 20.8 29.6

Table A2 - 9. Intersection OL-BFZ019a at drill core. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR4 81.50 82.40 81.50 82.40 0.6

OL-KR7 26.00 42.55 36.16 37.39 1.0

OL-KR22 138.80 146.05 114.90 145.60 1.0

OL-KR24 94.02 94.35 no data

OL-KR25 94.45 97.30 96.09 96.73 1.0

OL-KR28 154.50 155.50 154.50 155.50 1.0

OL-KR30 52.22 53.88 52.20 53.83 0.6

OL-KR34 78.32 78.83 78.30 78.80 0.6

OL-KR35 94.40 94.60 94.40 94.60 0.6

OL-KR36 153.60 156.80 154.77 155.90 0.6

OL-KR37 123.32 123.83 123.30 123.80 0.6

OL-KR38 88.10 88.75 88.10 88.70 0.6

OL-KR48 93.90 101.00 96.10 96.39 1.0

ONK-PH4 84.00 85.53 no data

ONKALO 931.90 963.00 no data

OL-BFZ019c

Figure A2 - 7. Brittle deformation zone OL-BFZ019c

104

The interpreted GSI value for OL-BFZ019c is 64 and interpreted Young’s modulus is 27.5 GPa. Geological description of OL-BFZ019c is following (Aaltonen et al. 2010):

OL-BFZ019c is a moderately dipping thrust fault with an approximate dip of c. 10 - 25 degrees towards the SSE. The fault is located a few tens of meters beneath fault OL-BFZ019a and is subparallel to it. The thickness of the fault core is approximately 0.1 – 1.4 m and the core zone is also frequently hydraulically conducting. Fracture-controlled kaolinisation, illitisation and sulphidisation are typical for the zone although occasionally illitisation is also pervasive. The core of the zone is characterized by RiIII-IV-sections or core loss in most of the drillhole intersections, although in a few drillholes significant geological evidence is lacking. However, the fault is inferred to intersect these drillholes on the basis of its general geometry, geophysical data and/or hydraulic connections. The geometry of the fault is based mainly on Mise-a-la-masse results in combination with geological observations in the drillholes and in the ONKALO tunnel.

105

Table A2 - 10. Intersections OL-BFZ019c at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.

Hole_id Geological

intersection

m_from

Geological

intersection

m_to

Core

GSI

Core

m_from

Core

m_to

Obs.

OL-KR4 116.10 116.30 --- No fractures

OL-KR10 76.70 77.60 75 76.70 77.60

OL-KR14 50.00 51.00 74 50.00 51.00

OL-KR22 188.45 200.50 66 188.50 191.30

OL-KR23 195.33 196.11 61 195.33 196.10

OL-KR24 112.55 116.20 62 155.30 155.80

OL-KR25 149.70 154.15 67 151.80 152.99

OL-KR27 277.51 284.40 40 280.75 284.60

OL-KR28 170.21 178.30 62 172.60 172.70

OL-KR30 81.09 83.48 58 82.17 82.72

OL-KR31 174.60 175.40 60 174.60 175.40

OL-KR36 197.40 201.10 65 197.40 197.90

OL-KR38 123.95 125.13 64 123.95 125.13

OL-KR40 273.64 282.25 36 273.87 273.96

OL-KR42 57.70 58.18 --- No data

OL-KR45 607.42 608.56 68 607.77 608.56

ONK-PH5 57.09 57.20 45 57.09 57.20 CL 11cm

ONKALO 1045.4 1045.7 64 1045.4 1045.7 ONK-BFI-104500-110850

106

Figure A2 - 8. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ019c. The interpreted GSI-value of the deformation zone core is 64.



27.5 41.7 47.6

GS

I

core

wid

th

20 0

40 2

60 4

80 6

OL-

KR

40

OL-

KR

27

OL-

KR

30

OL-

KR

31

OL-

KR

23

OL-

KR

24

OL-

KR

28

OL-

KR

38

OL-

KR

36

OL-

KR

22

OL-

KR

25

OL-

KR

45

OL-

KR

14

OL-

KR

10

ON

K-P

H5

ON

K-B

FI-

1045

00-1

1085

0

GSIwidth

107

Table A2 - 12. Intersections OL-BFZ019c at drill cores. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR4 116.10 116.30 116.10 116.30 0.6

OL-KR10 76.70 77.60 76.70 77.60 1.0

OL-KR14 50.00 51.00 50.00 51.00 1.0

OL-KR22 188.45 200.50 194.40 195.50 1.0

OL-KR23 195.33 196.11 195.30 196.10 1.0

OL-KR24 112.55 116.20 no data

OL-KR25 149.70 154.15 151.80 152.99 1.0

OL-KR27 277.51 284.40 283.00 283.50 1.0

OL-KR28 170.21 178.30 172.60 172.70 1.0

OL-KR30 81.09 83.48 82.50 83.20 0.6

OL-KR31 174.60 175.40 174.60 175.40 0.6

OL-KR36 197.40 201.10 197.40 197.90 0.6

OL-KR38 123.95 125.13 123.95 125.13 0.6

OL-KR40 273.64 282.25 273.87 273.96 0.6

OL-KR42 57.70 58.18 57.70 58.18 0.6

OL-KR45 607.42 608.56 607.77 608.56 0.6

ONK-PH5 57.09 57.20 no data


OL-BFZ020a

Figure A2 - 9. Brittle deformation zone OL-BFZ020a

The interpreted GSI value for OL-BFZ020a is 54 and the interpreted Young’s modulus is 22.6 GPa. Geological description of OL-BFZ020a is following (Aaltonen et al. 2010):

OL-BFZ020a is a moderately dipping thrust fault with an approximate dip of c. 20 degrees towards the SE. It is the main splay of another subparallel fault zone OL-BFZ020b, located at the maximum of a few tens of meters beneath OL-BFZ020a. The thickness of the fault core of OL-BFZ020a is approximately 0.1 – 2.7 m thick, with an average thickness of 1 m. Geologically OL-BFZ020a is not as distinct as OL-BFZ099 or OL-BFZ021. According to the RG-classification system, the fault core of OL-BFZ020a consists of densely fractured sections (RiIII) and clay-filled sections (RiIV) in most of the intersecting drillholes. In some drillholes, the fault core is characterized by

108

pervasive or fracture-controlled illitisation, kaolinisation and sulphidisation or weathering. Its geometry is strongly based on Mise-a-la-masse results, seismic reflectors revealed by VSP, 3D and 2D reflection surveys and Sampo Gefinex conductors (see Mattila et al. 2008 for more details). The thickness of the influence zone of OL-BFZ020a is in average 40 m, varying from 15 m to 73 m. It is usually characterized by increased fracturing, slickenside fractures, elevated hydraulic conductivity and sporadic alteration.

Table A2 - 13. Intersections OL-BFZ020a at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core

GSI

Core

m_from

Core

m_to Obs.

OL-KR1 141.18 143.95 40 142 143

OL-KR2 107.70 107.9 74 107.70 107.90

OL-KR3 46.30 48.80 51 47.40 48.50

OL-KR4 313.40 316.15 55 313.40 314.00

OL-KR7 227.01 228.80 51 227.00 228.53

OL-KR8 450.47 454.60 45 452.70 453.10

OL-KR9 444.20 445.10 59 444.20 445.10

OL-KR10 260.47 260.65 59 260.47 260.65

OL-KR11 300.61 305.39 55 304.00 305.00

OL-KR12 144.00 150.54 71 144.00 146.00

OL-KR13 113.49 115.31 68 113.49 115.31

OL-KR14 183.00 184.20 39 183.15 183.30

OL-KR15 148.20 148.80 30 148.20 148.80

OL-KR16 147.4 148.2 40 147.40 148.20 CL 25 cm

OL-KR17 123.50 130.92 52 128.30 129.80

OL-KR20 37.36 39.48 --- 37.36 39.48

OL-KR20B 39.50 42.15 63 39.50 41.67

OL-KR22 390.76 393.06 72 390.80 391.50

OL-KR23 427.60 428.50 72 427.60 428.50

OL-KR24 330.8 331.8 80 330.80 331.80

OL-KR25 347.00 352.25 52 350.56 350.80

OL-KR27 547.38 459.59 72 547.38 549.59

OL-KR28 388.00 389.80 63 388.00 388.65

OL-KR29 324.00 325.00 67 324.00 325.00

OL-KR32 86.79 88.07 82 86.79 88.07

OL-KR38 319.28 323.53 68 320.48 320.85

OL-KR39 146.00 149.21 59 147.00 148.60

OL-KR40 604.64 607.45 59 606.90 607.10

OL-KR41 150.00 151.00 --- No data

OL-KR42 183.03 198.83 --- No data

OL-KR44 652.00 665.00 62 653.05 653.36

OL-KR46 285.00 286.00 60 285.00 286.00

OL-KR48

OL-KR49

OL-KR55

OL-KR56

338.99

1010.4

507.16

771.68

342.15

1012.57

508.36

793.52

53

59

62

50

339.60

1010.42

507.15

780.25

340.20

1012.58

508.37

781.08

ONKALO 3157 3158 54 ONK-BFI-3159

109

Figure A2 - 10. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ020a. The interpreted GSI-value of the deformatio zone core is 54.



22.6 31.3 40.4

GS

I

core

wid

th

20 0

40 1

60 2

80 3

100 4

OL-

KR

1O

L-K

R1

5O

L-K

R1

4O

L-K

R1

6O

L-K

R8

OL

-KR

56

OL-

KR

3O

L-K

R7

OL

-KR

17

OL

-KR

25

OL

-KR

48

OL-

KR

4O

L-K

R1

1O

L-K

R9

OL

-KR

10

OL

-KR

39

OL

-KR

40

OL

-KR

49

OL

-KR

46

OL

-KR

44

OL

-KR

55

OL

-KR

20B

OL

-KR

28

OL

-KR

29

OL

-KR

13

OL

-KR

38

OL

-KR

12

OL

-KR

22

OL

-KR

23

OL

-KR

27

OL-

KR

2O

L-K

R2

4O

L-K

R3

2O

L-K

R2

0O

NK

-BF

I-31

59

GSIwidth

110

Table A2 - 15. Intersections OL-BFZ020a at drill cores. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR1 141.18 143.95 142.00 143.00 1.0

OL-KR2 107.70 107.90 107.70 107.90 1.0

OL-KR3 46.30 48.80 47.40 48.50 1.0

OL-KR4 313.40 316.15 313.40 314.00 1.0

OL-KR7 227.01 228.80 227.10 228.50 1.0

OL-KR8 450.47 454.60 452.70 453.10 1.0

OL-KR9 444.20 445.10 444.20 445.10 1.0

OL-KR10 260.47 260.65 260.47 260.65 1.0

OL-KR11 300.61 305.39 304.00 305.00 1.0

OL-KR12 144.00 150.54 144.00 146.00 1.0

OL-KR13 113.49 115.31 113.49 115.31 1.0

OL-KR14 183.00 184.20 183.00 184.00 1.0

OL-KR15 148.20 148.80 148.20 148.80 1.0

OL-KR16 147.4 148.2 147.40 148.20 1.0

OL-KR17 123.50 130.92 no data

OL-KR20 37.36 39.48 37.36 39.48 1.0

OL-KR20B 39.50 42.15 39.50 41.67 1.0

OL-KR22 390.76 393.06 390.80 391.50 1.0

OL-KR23 427.60 428.50 no data

OL-KR24 330.8 331.8 330.80 331.80 1.0

OL-KR25 347.00 352.25 350.50 350.80 1.0

OL-KR27 547.38 459.59 547.38 549.59 1.0

OL-KR28 388.00 389.80 388.00 389.80 1.0

OL-KR29 322.71 325.58 324.00 325.00 0.6

OL-KR32 86.79 88.07 86.79 88.07 0.6

OL-KR38 319.28 323.53 320.50 320.90 0.6

OL-KR39 146.88 148.83 147.00 148.00 0.6

OL-KR40 604.77 607.70 604.99 605.02 0.6

OL-KR41 150.00 151.00 150.00 151.00 1.0

OL-KR42 183.03 198.83 193.40 194.37 0.6

OL-KR44 652.00 665.00 653.05 653.36 0.6

OL-KR46 285.00 286.00 285.00 286.00 0.6

OL-KR48

OL-KR49

OL-KR55

OL-KR56

338.99

1010.4

507.16

771.68

342.15

1012.57

508.36

793.52

339.60

507.15

340.20

508.37

0.6

no data

0.6

no data

ONKALO 3157 3158 no data

111

OL-BFZ020b

Figure A2 - 11. Brittle deformation zone OL-BFZ020b

The interpreted GSI value for OL-BFZ020b is 50 and interpreted Young’s modulus is 20.5 GPa. Geological description of OL-BFZ020b is following (Aaltonen et al. 2010):

OL-BFZ020b is the lower splay of OL-BFZ020a with an approximate dip of c. 20 degrees towards the SE (Figure 4 32). The thickness of the fault is approximately 0.2 to 8.6 m, with an average thickness of c. 1 m. The fault is cross-cut by OL-BFZ020a to the SE. According to the RG-classification system, the core consists of densely fractured sections (RiIII) and clay-filled sections (RiIV) in all of the intersecting drillholes. Hydraulic conductivity is commonly also elevated. There are not many indications of hydrothermal alteration related to the core of the fault. Kaolinisation is the most common type of alteration (pervasive as well as fracture-controlled). Sporadic illitisation and sulphidisation are also present. The geometry of the zone is strongly based on Mise-a-la-Masse and Sampo Gefinex results and VSP reflectors. The seismic reflectors detected from the ground surface are strongly concentrated to fault zone OL-BFZ020a.

112

Table A2 - 16. Intersections OL-BFZ020b at drill cores. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

Obs

OL-KR4 370.08 370.6 70 370.10 370.60

OL-KR7 285.70 287.80 52 287.44 287.70

OL-KR8 542.00 562.00 39 552.37 552.60

OL-KR9 473.70 474.70 74 473.70 474.70

OL-KR10 326.00 327.45 58 326.00 326.40

OL-KR12 271.87 272.97 59 271.87 272.97

OL-KR22 423.35 425.65 77 423.90 425.30

OL-KR24 380.73 385.55 55 380.83 381.45

OL-KR25 369.31 373.20 72 369.90 370.90

OL-KR28 445.40 445.75 49 445.40 445.70

OL-KR29 333.55 337.75 55 336.50 336.70

OL-KR38 372.53 392.62 56 383.48 384.08

OL-KR40 630.45 631.90 59 630.40 631.20

OL-KR42 272.83 274.36 --- No data

OL-KR44 668.50 674.80 58 668.72 668.95

OL-KR48

ONKALO

376.35

3285.00

382.85

3317.00

57

50

378.22

382.85

ONK-BFI-3285

Figure A2 - 12. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ020b. The interpreted GSI-value of the deformation zone core is 50.

GS

I

core

wid

th

20 0

40 2

60 4

80 6

OL-

KR

8

OL-

KR

28

OL-

KR

7

OL-

KR

24

OL-

KR

29

OL-

KR

38

OL-

KR

48

OL-

KR

10

OL-

KR

44

OL-

KR

12

OL-

KR

40

OL-

KR

4

OL-

KR

25

OL-

KR

9

OL-

KR

22GSIwidth

113



20.5 28.9 42.8

Table A2 - 18. Intersections OL-BFZ020b at drill cores. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR4 370.08 370.6 370.10 370.60 1.0 OL-KR7 285.70 287.80 285.70 287.80 1.0 OL-KR8 542.00 562.00 552.80 555.30 1.0

OL-KR9 473.70 474.70 473.70 474.70 1.0 OL-KR10 326.00 327.45 326.00 326.40 1.0 OL-KR12 271.87 272.97 271.80 272.97 1.0

OL-KR22 423.35 425.65 423.90 425.30 1.0 OL-KR24 380.73 385.55 380.73 785.55 1.0 OL-KR25 369.31 373.2 369.90 370.90 1.0

OL-KR28 445.40 445.75 445.40 445.70 1.0 OL-KR29 333.55 337.75 336.50 336.70 0.6 OL-KR38 372.53 392.62 374.04 375.55 0.6

OL-KR40 630.45 631.90 630.40 631.20 0.6 OL-KR42 272.83 274.36 273.50 273.85 0.6 OL-KR44 668.50 674.80 668.72 668.95 0.6

OL-KR48 ONKALO

376.35 3285.00

382.85 3317.00

380.25

380.55

0.6

no data

OL-BFZ021

Figure A2 - 13. Brittle deformation zone OL-BFZ021 (c. 200 m below ONKALO)

114


OL-BFZ021 is a moderately dipping thrust fault, with an approximate dip of 20 degrees towards the SSE. OL-BFZ021 and OL-BFZ099 are considered as two splays of a one single zone, combining into a single zone in the central part of the site volume. Similarly to OL-BFZ099, OL-BFZ021 is geologically well-pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, alteration and varying amounts of incohesive fault breccia and gouge (i.e. crushed rock). The thickness of the fault core varies from 1 to 8 m. the average thickness being approximately 4 m. As for the OL-BFZ099, the majority of the core intersections fall into the RiIII-category of the RG-classification, but in a few intersections RiIV and RiV-sections also occur. Again, this corresponds to the variation in the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone shows evidence of recurrent movements within the brittle regime as ductile and semi-ductile precursors are in many drill cores overprinted first by welded fractures and cohesive breccias and later by younger fractures.



m_from


m_to

Core

GSI

Core

m_from

Core

m_to

Obs

OL-KR1 611.00 618.00 51 616.05 616.75

OL-KR2 600.00 607.00 42 605.38 605.68

OL-KR3 470.00 473.00 72 471.65 472.65

OL-KR4 756.00 764.00 37 760.95 761.40

OL-KR5 481.00 483.50 45 481.75 483.27

OL-KR6 468.00 471.00 52 469.00 469.70

OL-KR7 689.90 692.02 34 691.00 692.12

OL-KR11 625.02 626.47 42 625.02 626.40

OL-KR12 664.80 673.00 55 670.90 671.75

OL-KR19 464.00 766.00 70 464.75 465.35

OL-KR29 776.51 781.02 32 776.98 777.39

OL-KR43 340.00 345.93 --- No data

OL-KR47 523.18 535.99 43 524.65 525.14

115




18.6 27.2 31.0



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR1 611.00 618.00 615.78 616.04 1.0

OL-KR2 600.00 607.00 600.96 604.2 1.0

OL-KR3 470.00 473.00 472.2 473.14 1.0

OL-KR4 756.00 764.00 756.00 764.00 1.0

OL-KR5 481.00 483.50 1.0

OL-KR6 468.00 471.00 469.00 469.70 1.0

OL-KR7 689.90 692.02 1.0

OL-KR11 623.00 627.00 625.36 626.86 1.0

OL-KR12 664.80 673.00 671.36 672.4 1.0

OL-KR19 464.00 766.00 464.54 465.38 1.0

OL-KR29 776.51 781.02 776.97 777.39 0.6

OL-KR43 340.00 345.93 342.28 342.38 0.6

OL-KR47 523.18 535.99 524.65 525.14 0.6

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL

-KR

29

OL-

KR

7

OL-

KR

4

OL-

KR

2

OL

-KR

11

OL

-KR

47

OL-

KR

5

OL-

KR

1

OL-

KR

6

OL

-KR

12

OL

-KR

19

OL-

KR

3

GSIwidth

116

OL-BFZ039

Figure A2 - 15. Brittle deformation zone OL-BFZ039


The intersection in KR29 is composed of VGN and DGN, with some short sections of PGR. The feldspars are often altered to illite. The intersection contains a few old and welded fractures with calcite and pyrite infillings, especially in the PGR. Several of the fractures contain kaolinite and illite infillings. Accordingly, a majority of the fractures show signs of water conductivity and some of them also have green-grey clay infillings. There is, however, no indication of water flow in the flow measurements. The intersection exhibits 61 fractures, with a dip direction towards SE with a moderate dip. The rock is more fractured in section 543.80-547.12 m (37 joints). The intersection exhibit 29 fractures with a slickenside surface, which have a striation direction varying from SE to SW, with a moderate plunge.



m_from


m_to

Core

GSI

Core

m_from

Core

M_to

Obs.

OL-KR7 473.92 473.92 --- 1 fracture

OL-KR29 533.00 548.55 60 543.80 546.4

117




35.9 38.6 41.6



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR7 473.92 473.92 no data

OL-KR29 533.00 548.55 543.80 546.40 0.6

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-KR29

GSIwidth

118

OL-BFZ043



A set of parallel quite steeply-dipping slickensides in KR10, which cross-cut the foliation. Slight pyrite coatings on fracture surfaces.

The first intersection in ONKALO is composed of one main fault (87/100°), which crosscuts the whole tunnel. This fault contains a ca. 15 cm wide section of epidote altered rock around the fracture in the left wall. As fracture filling it contains calcite, quartz, epidote and unidentified clays with a maximum thickness of 30 mm. Striation could not be determined from the slickenside surface, but the fracture has faulted to MGN inclusions dextrally when viewed from south to north in the left wall. In addition to the main fault the intersection contains several conjugate fractures either combining with the main fault or in the near vicinity of it. These fractures mainly have an undulating smooth profile and mainly contain calcite and epidote as fracture filling. This gives an indication of some kind of a hydrothermal alteration within this zone. The intersection contains a ca. 1.40 m wide “damage zone” with approximately equal extent on both sides of the main fault.

The second intersection in ONKALO is composed of two tunnel crosscutting undulating slickensided fractures and some shorter fractures near them. Filling minerals are calcite, quartz, some epidote, chlorite, illite, pyrite and galena also exists. The width of these fracture infillings changes between 2-50 mm. The surrounding rock is weakly banded, slightly fractured and unaltered veined gneiss.

119

Table A2 - 25. Intersections OL-BFZ043 at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

Obs.

OL-KR10 271.41 271.60 49 271.5 271.6

ONKALO 1364.80 1366.00 62 ONK-BFI-136480-136600

ONKALO 2232.90 2234.50 73 ONK-BFI-223290-223450




56.9 56.9 57.2

GS

I

core

wid

th20 0

40 1

60 2

80 3

OL-

KR

10

ON

K-B

FI-

1364

80-1

3660

0

ON

K-B

FI-

2232

90-2

2345

0

GSIwidth

120



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR10 271.41 271.60 271.50 271.60 1.0



OL-BFZ045b

Figure A2 - 19. Brittle deformation zone OL-BFZ045b

The interpreted GSI value for OL-BFZ045b is 43 and determined Young’s module is 28.6 GPa. No seismic data were available from drillhole intersections and determined Young’s modulus for OL-BFZ045b is the average value of all determined brittle deformations zones. Geological description of OL-BFZ045b is following (Aaltonen et al. 2010):

A narrow zone outlined by two parallel, slickenside fractures. A white calcite vein between the fractures (about 1.5 cm); the vein shows step-like small-scale faulting with movement of about 1 cm/step (3-4 cm total); right-handed from above the core. Graphite present in the fractures. Resembles the "storage hall fault” OL-BFZ100.

121

Table A2 - 28. Intersections OL-BFZ045b at ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

Obs

ONKALO 3350 3352 56 ONK-BFI-3350

ONKALO

ONKALO

4377.3

ONK-TDT-4399-30-56.3

4389

ONK-TDT-4399-30-70.8

41

46

ONK-BFI-4377

ONK-TDT-30-BFI-56.3

Figure A2 - 20. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ045b. The Interpreted GSI-value of the deformation zone core is 43.

GS

I

core

wid

th20 0

40 1

60 2

80 3

ON

K-B

FI-

4377

ON

K-T

DT

-30-

BF

I-56

.3

ON

K-B

FI-

3350

GSIwidth

122

OL-BFZ084



KR1: Fractures parallel with foliation are abundantly present as well as fractures perpendicular to foliation. Macadam-looking core sample, however, show some slickenside surfaces. TV-image shows 2 – 3 clear open fractures. Fracture surfaces carry powder-like clay minerals. Porosity and seriticisation (zinnwaldite) are detected. Two remarkable water-flow anomalies are situated in this section.

KR3: Pegmatite containing voluminous mica-rich parts, around which the rock has slipped and plenty of slickensides were born. Slight alteration, some pyrite on fracture surfaces and sporadic illite-coatings.

KR7: A short breakage, which is strongly aided by drilling. Strong geophysical anomalies, except water-conductivity are insignificant. Older strong ductile shear is visible.

TK2: Dextral fault zone upon a high-grade ductile shear zone precursor. The ductile shear zone has been reactivated and the resulting fractures are subsequently healed and welded by calcite and pyrite.

KR39: The intersection locates in varying VGN/DGN/PGR rock. It consists of three densely fractured zones with less fractured rock between them. The depths of the three core zones are: 178.94 - 179.26 m. 182.84 - 183.87 m and 186.51 - 187.52 m. The densely fractured sections are mostly in VGN. while DGN and PGR are less fractured. The main fracture direction is at 25-50/160. The fillings are chlorite, graphite, clay, pyrite and calcite. The intersection is altered with chloritization and graphitization at core zones. The less fractured parts of the section are only very weakly altered.

123

ONK-PH10: A densely fractured section (fracture spacing from 0.5-15 cm) with a very broken core zone (BFI_3540), where the core has broken up into pieces (rubble) of about 4 cm and less in diameter. Fracture-fillings are rather thin.

Table A2 - 29. Intersections OL-BFZ084 at drill core and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

Obs.

OL-KR1 108.51 110.36 62 108.51 109.25

OL-KR3 158.20 162.75 42 158.20 158.60

OL-KR7 409.25 410.40 55 409.30 410.40

OL-KR39 178.05 187.60 45 186.40 187.55 CL 40 cm

ONKALO

ONKALO

ONKALO

3540.40

4270.00

ONK-TDT-4399-30-62.5

3543.80

4295.00

ONK-TDT-4399-30-85.0

50

52

43

ONK _BFI_3540

ONK-BFI-4276

ONK-TDT-4399-30-

BFI-62.5


GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-

KR

3

OL-

KR

39

OL-

KR

7

OL-

KR

1

ON

K-T

DT

-439

9-30

-BF

I-62

.5

ON

K-B

FI-

3540

ON

K-B

FI-

4276

GSIwidth

124



27.4 37.7 43.0



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR1 108.51 110.36 108.60 109.90 1.0

OL-KR3 158.20 162.75 159.00 161.70 1.0

OL-KR7 409.25 410.40 409.30 410.40 1.0

OL-KR39 178.05 187.60 186.40 187.50 0.6

ONKALO

ONKALO

ONKALO

3540.40

4270

ONK-TDT-4399-30-62.5

3543.80

4295

ONK-TDT-4399-30-85.0

no data

no data

no data

OL-BFZ099



OL-BFZ099 is a site-scale, moderately dipping thrust fault with an approximate dip of 40 degrees towards the SE. The fault zone is geologically well-pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, hydrothermal fracture-controlled/pervasive illitisation and kaolinisation and variable amounts of incohesive fault breccia and gouge (i.e. crushed rock). The thickness of the fault core varies from 1 to 13 m, the average thickness being 5 metres. A majority of the core intersections fall into the RiIII-category of the RG-

125

classification (fracture-structured with minor fracture filling), but in few intersections also RiIV (crush-structured with clay fracture fillings) and RiV (clay-structured) sections occur. This corresponds to the variation on the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone also shows evidence of recurrent movements within the brittle regime, as ductile and semi-ductile precursors are in many drill cores overprinted first by cataclasites and later by younger fractures.

The thickness of the fault zone (core zone plus influence zone) is on average about 44 m but varies between 11 and 103 m in different drillholes. Characteristic features of the influence zone are the abundance of slickensides, pervasive illitisation, kaolinisation and sporadic occurrence of fracture-controlled sulphidisation and, in many cases, subsidiary fault core sections.



m_from

Geologiclal intersection

m_to

Core

GSI

Core

m_from

Core

m_to

Obs.

OL-KR1 525.20 526.20 55 525.65 526.20

OL-KR2 471.00 472.35 49 471.23 472.27

OL-KR3 470.50 471.40 43 466.10 466.44

OL-KR4 757.70 762.70 37 760.95 761.40

OL-KR5 278.97 282.44 40 279.48 280.25 CL 77 cm

OL-KR6 163.20 166.45 66 162.80 164.80

OL-KR7 689.90 692.00 34 691.00 692.12

OL-KR11 625.02 626.47 42 625.02 626.40

OL-KR12 582.40 584.10 61 582.40 584.10

OL-KR13 445.50 468.00 51 453.20 453.62

OL-KR19 253.35 259.82 54 259.00 259.65

OL-KR20 410.59 424.45 50 416.29 417.70

OL-KR20 426.90 431.14 43 427.40 428.40

OL-KR29 776.51 781.02 32 776.98 777.39 strongly weathered

OL-KR33 275.91 280.43 42 275.90 276.30

OL-KR43 97.10 102.10 --- No data available

OL-KR47

OL-KR55

OL-KR56

324.44

972.51

1152.46

343.80

998.40

1167.79

40

54

49

330.74

984.4

1156.96

330.9

985.52

1157.49

126

Figure A2 - 24. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ099. The interpreted GSI-value of the deformation zones core (GSI =41).



14.4 27.8 44.7

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-

KR

29O

L-K

R7

OL-

KR

4O

L-K

R5

OL-

KR

47O

L-K

R11

OL-

KR

33O

L-K

R20

OL-

KR

3O

L-K

R2

OL-

KR

56O

L-K

R20

OL-

KR

13O

L-K

R55

OL-

KR

19O

L-K

R1

OL-

KR

12O

L-K

R6

GSIwidth

127


Hole_id Geological intersection Geological intersection Core Core Distance btw

m_from m_to m_from m_to transm and recvr

OL-KR1 525.20 526.20 525.36 525.84 1.0

OL-KR2 471.00 472.35 471.42 472.56 1.0

OL-KR3 470.50 471.40 466.10 466.44 1.0

OL-KR4 757.70 762.70 760.84 761.32 1.0

OL-KR5 278.97 282.44 no data

OL-KR6 163.20 166.45 162.80 164.80 1.0

OL-KR7 689.90 692.00 no data

OL-KR11 625.02 626.47 625.36 626.86 1.0

OL-KR12 582.40 584.10 581.00 584.00 1.0

OL-KR13 445.50 468.00 453.20 453.62 1.0

OL-KR19 253.35 259.82 259.00 259.66 1.0

OL-KR20 410.59 424.45 416.98 417.36 1.0

OL-KR20 426.90 431.14 427.40 428.40 1.0

OL-KR29 776.51 781.02 776.95 777.45 0.6

OL-KR33 275.91 280.43 275.89 276.31 0.6

OL-KR43 97.10 102.10 97.74 98.18 0.6

OL-KR47 324.44 343.80 330.74 330.90 0.6

OL-KR55 972.51 998.40 no data

OL-KR56 1152.46 1167.79 no data

128

OL-BFZ100

Figure A2 - 25. Brittle deformation zone OL-BFZ100. Deformation zone is coloured based on interpreted rock quality, see the legend in the Figure.


The fault consists of a clearly definable core and transition zone; the core has a varying width of 0.15 to 2 metres and has in places strongly developed schistose fabric with associated slickensided surfaces. Quartz, pyrite, chalcopyrite, graphite, galena and talc mineralisations can be observed within the fault core. Pyrite mineralisation occurs within cavities associated with quartz-filled tension veins. Chalcopyrite seems to be associated with calcite-filled fractures/tension veins. The fault zone shows sinistral sense of movement by numerous kinematic indicators.

129

Table A2 - 35. Geological indications for the OL-BFZ100 intersections. Core m_from and core m_to are the depths of the selected GSI value of intersection in question.

Hole_id


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-PH1 151.64 154.32 26 152.38 152.62

OL-PH4 27.10 30.57 70 28.76 29.6

OL-KR22 337.65 340.45 67 338.20 339.60

OL-KR23 372.5 373.02 67 372.50 373.02

OL-KR25 216.5 222.05 43 217.65 218.31

Ol-KR26 95.80 98.25 70 96.82 97.9

OL-KR28 170.21 178.30 62 172.60 173.20

OL-KR34 48.38 53.77 43 48.38 49.46

OL-KR37 56.23 57.5 47 56.19 56.71

OL-KR42 183.03 198.83 --- No data




ONKALO 1592.90 1595.00 40 ONK_BFI_159290_159500

ONKALO 1819.00 1831.00 43 ONK_BFI_181900_183100

ONKALO 2481.50 2482.00 56 ONK-BFI-248150-248200

ONKALO 2931.50 2937.50 46 ONK-BFI-293150-293750

Figure A2 - 26. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ100. The interpreted GSI-value of the core is 43.

GS

I

core

wid

th

20 0

40 2

60 4

80 6

OL-

KR

25

OL-

KR

34

OL-

KR

37

OL-

KR

28

OL-

KR

22

OL-

KR

23

Ol-K

R26

OL-

PH

1

OL-

PH

4

ON

K-B

FI-

1592

90-1

5950

0

ON

K-B

FI-

1819

00-1

8310

0

ON

K-B

FI-

2931

50-2

9375

0

ON

K-B

FI-

2481

50-2

4820

0

ON

K-B

FI-

1285

0-12

930

ON

K-B

FI-

5215

0-52

300

ON

K-B

FI-

9002

0-90

640

GSIwidth

130



32.0 44.9 50.1



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-PH1 151.64 154.32 no data ONK-PH4 27.10 30.57 27.01 30.57 0.6

OL-KR22 337.65 340.45 338.20 339.60 1.0 OL-KR23 372.5 373.02 no data OL-KR25 216.5 222.05 217.32 218.31 1.0

Ol-KR26 95.80 98.25 96.82 97.90 1.0 OL-KR28 170.21 178.30 177.02 178.02 1.0 OL-KR34 48.38 53.77 49.23 50.17 0.6

OL-KR37 56.23 57.5 56.23 57.50 0.6 OL-KR42 183.03 198.83 197.70 198.10 0.6 ONKALO 128.50 129.30 no data

ONKALO 521.50 523.00 no data ONKALO 900.20 906.40 no data ONKALO 1592.90 1595.00 no data

ONKALO 1819.00 1831.00 no data ONKALO 2481.50 2482.00 no data ONKALO 2931.50 2937.50 no data

131

OL-BFZ101


The interpreted GSI value for OL-BFZ101 is 45 and determined Young’s module is 28.6 GPa. No seismic data were available from drillhole intersections and determined Young’s modulus for OL-BFZ0101 is the average value of all determined brittle deformations zones. Geological description of OL-BFZ101 is following (Aaltonen et al. 2010):

Brittle fault intersection, which is visible across the whole tunnel, has a trace length of more than 40 meters. The fault plane has an average dip/dip direction of 10/151. The width of the zone is approximately 2 meters. The fault has partly a semi-brittle character as the foliation near the fault shows well-developed deflection and thus indicating that the hanging wall of the fault has moved towards west (reverse fault). The fault plane crosscuts the foliation. Accordingly, sense-of-movement viewed from south is sinistral. The fault has a well developed 10-30 cm wide core, which contains of intensively crushed rock (0.1-30 mm in diameter) and greenish clay. The core can be defined as fault breccia, as most of the material consists of rock pieces (70-80%).The fault has also an intensively altered "transition intersection" in which the rock is quite homogenous K-feldspar porphyric tonalite/granodiorite; the K-feldspar phenocrysts are 5-50 mm in diameter and are both eu- to subhedral. The width of this K-feldspar porhyritic zone is 0.2-2 m in the hanging wall and approximately 1 meter in the footwall.

132

Table A2 - 38. Intersections OL-BFZ101 at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.

Hole_id


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

Obs

ONKALO 65.6 68.00 71 ONK-BFI-6560-6575

Q_median

OL-PH1 98.59 99.76 45 98.59 99.76

Figure A2 - 28. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ101. The interpreted GSI-value of the deformation zones core is 45.

GS

I

core

wid

th20 0

40 1

60 2

80 3

OL-

PH

1

ON

K-B

FI-

6560

-657

5

GSIwidth

133

OL-BFZ106



KR22: Inside the section lies the semi-ductile intersection SFI_OL_KR22_04335-06530. A few old, “welded” fractures with calcite infilling are present. The intersection contains several slickensides between 46.00-48.00 m. Slickensides follow the foliation. The slickenside surfaces often contain graphite and chlorite. The beginning of this section is badly crushed (partly mechanical). Signs of water conductivity were observed in sections 50.00-51.20 m and 66.53-67.12 m. The fractures in the former section contains greenish clay (1 mm thick, unidentified) and the latter graphite, kaolinite and some unidentified greenish clay.

KR27: The intersection contains mostly VGN with short sections of PGR and a grey-red, fine-medium grained, sheared rock that resembles VGN at 86.31-88.03 m and 92.80-94.25 m. The VGN is greenish in colour, due to propable illite alteration. The PGR exhibits a red (paleo)oxidation. The intersection is strongly altered and shows a paleoshearing, which probably later has been reactivated. The rock is partly porous because of the mineral leaching. The rock exhibits in one joint a black mineral (goethite?) and a few gouges with unidentified clay minerals. Water flowing has been determined in following fractures: 84.60 m, 86.40 m, 88.00 m, 89.80 m, 92.75 m and 95.50 m. The intersection also contains old, randomly oriented “welded” fractures; fractures are welded by calcite.

KR40: Short intersection in PGR, with fractures mainly in dip direction 030/60. Fracture fillings are clay, carbonate and yellowish mineral (epidote/sericite?). The PGR around fractures is weakly altered with epidotization/sericitization.

134



m_from

Geolocical intersection

m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR22 42.80 73.15 10* 46.00 46.27

OL-KR27 84.50 96.50 33 95.40 95.70

OL-KR40

OL-KR56

395.10

364.10

395.75

382.37

60

40

395.10

369.49

395.75

369.86

* estimated GSI value




19.9 22.5 36.3



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR22 42.80 73.15 45.98 46.54 1.0 OL-KR27 84.50 96.50 95.40 95.70 1.0

OL-KR40 395.10 395.75 395.10 395.75 0.6

OL-KR56 364.10 382.37 no data

GS

I

core

wid

th0 0

20 0.5

40 1

60 1.5

80 2

OL-

KR

22

OL-

KR

27

OL-

KR

56

OL-

KR

40

GSIwidth

135

OL-BFZ118


The interpreted GSI value for OL-BFZ118 is 60 and determined Young’s module is 28.6 GPa. No seismic data were available from drillhole intersections and determined Young’s modulus for OL-BFZ0118 is the average value of all determined brittle deformations zones. Geological description of OL-BFZ118 is following (Aaltonen & al. 2010):

ONK-BFI-71310-71805: Six single slickenside surfaces that cut the tunnel. Only few SS surfaces combine. Fracture fillings (1-40 mm): pyrite, calcite, kaolinite, quartz, chlorite, hornblende and chalcopyrite. Thick (~5 cm) calcite and quartz filling in one fracture. Fracture orientations: 83/081, 82/073, 72/086 (right wall). Orientations are similar in the left wall. Left-handed movement observed in PGR vein on the right wall.

Table A2 - 42. Intersections OL-BFZ118 at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view

Hole_id Geological

intersection

m_from

Geolocical

intersection

m_to

Core

GSI

Core

m_from

Core

m_to

Obs

ONKALO 713.10 718.05 72 ONK-BFI-71310-71805

Q_median

ONK-PH3 19.2 21.8 60 20.35 21.8

136


OL-BFZ146



“Liikla shear zone”, a major ductile shear zone detected in TK14 and lineament interpretation (SURFMAGN0003 and SURFMAGN0068). In TK14, the zone is characterised by strongly foliated, pervasively altered and weathered veined gneiss. The mesosome is totally chloritised and hematised and the neosome kaolinitised and illitised. Most foliation planes are weathered open, which gives the rock a densely fractured look. The sense-of-shear remains ambiguous but the rock contains some sub-

GS

I

core

wid

th

20 0

40 2

60 4

80 6

ON

K-P

H3

ON

K-B

FI-

7131

0-71

805

GSIwidth

137

horizontal lineations plunging slightly towards the WSW. The upper parts of drillholes KR27, KR40 and KR45 are highly fractured (numerous RiIII-RiIV zones), indicating that also brittle deformation may be related to this zone. The zone has also been fixed to highly fractured sections in drillholes KR49 and KR50, showing slickenside fractures, alteration and indications of semi-brittle deformation. According to the recent magnetic interpretation, the zone may be cut by several N-S trending fault zones.



m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR27 10.91 11.96 ---

OL-KR27B 14.45 15.53 67 14.45 15.53

OL-KR40 22.93 23.39 ---

OL-KR40B 16.20 23.20 60 20.50 23.20

OL-KR45 58.10 62.55 63 61.10 61.75

OL-KR49 323.62 324.49 58 323.62 324.49

OL-KR50

OL-KR51

OL-KR52

OL-KR56

OL-KR57

391.01

417.39

355.93

328.71

348.47

393.02

418.37

361.59

364.02

364.86

49

49

62

34

35

391.28

417.38

360.12

347.35

351.05

391.77

418.38

361.52

347.97

351.53


GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-

KR

56

OL-

KR

57

OL-

KR

50

OL-

KR

51

OL-

KR

49

OL-

KR

40B

OL-

KR

52

OL-

KR

45

OL-

KR

27B

GSIwidth

138



17.8 24.6 30.5



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR27 10.91 11.96 no data

OL-KR27B 14.45 15.53 14.45 15.53 1.0

OL-KR40 22.93 23.39 22.93 23.39 0.6

OL-KR40B 16.20 23.20 19.28 19.64 0.6

OL-KR45 58.10 62.55 60.76 61.53 0.6

OL-KR49 323.62 324.49 323.62 324.49 0.6

OL-KR50

OL-KR51

OL-KR52

OL-KR56

OL-KR57

390.01

417.39

355.93

328.71

348.47

393.02

418.37

361.59

364.02

364.86

391.28

417.38

360.12

391.77

418.38

361.52

0.6

0.6

0.6

no data

no data

OL-BFZ152


139

The interpreted GSI value for OL-BFZ0152 is 62 and interpreted Young’s modulus is 43 GPa. There is a significant difference in Young’s modulus between this and previous report. Geological description of OL-BFZ152 is following (Aaltonen et al. 2010):

The zone is based on magnetic lineament NEWSURFMAGN18. It is observed as a magnetic minimum.

OL_KR44_BFI_79108_79556: The intersection locates in moderately banded VGN, between a PGR+MGN (hanging wall) and TGG (roof wall) sections. It consists of 29 fractures of which 12 are slickensided. Fracture fillings consist mostly of chlorite, kaolinite, illite and pyrite, with occasional clay and calcite. Main fracture directions are a subvertical fracture direction (also core direction) dipping 70-90 degrees to directions 105 and 285, and fracture directions 70/220 and 15/320. The measured lineations are quite variable, showing several drends and dips. The core of the intersection locates at 793.30 - 793.68 m, and consists of densely fractured rock (mostly slickensides), but no real fault breccia. Outside the core there are less fractures and the outer borders of the intersection is defined by lack of slickensided/chlorite filled fractures. The alteration in the intersection is local weak illitization with pinitization of cordierite.

OL_KR45_BFI_6858_7121: The intersection locates at the upper contact of VGN to underlying KFP. The transition of rock types occur at 68.20 - 68.10 m. The intersection consists of 21 logged fractures of which one is grain filled and two have weak lineations, suggesting more a weak BFI type than clear BJI type intersection. The fracture fillings are mainly clay, chlorite and illite with occational calcite, pyrite and epidote. There is a dominating fracture direction 30/360 and minor directions: 50/330 and 10/220. The core of the intersection locates at 68.89 - 69.16 m and consists of one grain filled fracture at 68.89 m and densely fractured rock below it. The intersection shows weak to moderate illitization, epidotization and chloritization, as also the wall rock. The outer borders of the intersection are defined by lack of chlorite filled fractures.



m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR44 791.08 795.56 60 793.30 793.68

OL-KR45

OL-KR55

68.58

365.01

71.21

365.69

68

64

68.89

365.00

70.03

365.70

140




43 51.3 54.9



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR44 791.08 795.56 793.30 793.68 0.6

OL-KR45

OL-KR55

68.58

365.01

71.21

365.69

68.89

365.73

69.16

366.23

0.6

0.6

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-

KR

44

OL-

KR

55

OL-

KR

45

GSIwidth

141

OL-BFZ160



The zone is based on topographic lineament TOPO0465 correlated to drillhole intersection OL_KR45_BFI_17809_19536. The intersection is weakly mineralized in low temperature, and a large portion of the fractures (locally also fault breccia) are loosely closed with calcite, pyrite and graphite. The BFI consists of 152 logged fractures of which 14 have clearly slickensided surfaces. Most other fractures have clay or crushed rock as filling, showing clear fault type intersection. Typical fracture filling minerals are: chlorite, graphite, pyrite, calcite, illite and clay minerals. The core of the intersection locates at 185.05 - 185.45 m and consists of fault breccia/gouge that is washed away during drilling (core loss). The fracture directions are variable but three fracture directions can be observed: 15/330, 30/200 and 45/290. The number of measured lineations is small but 2 measurements each show following lineations: 25/345, 20/030 and 5/090. The intersection is moderately to strongly altered with sulphidization, illitization and carbonatization. The borders of the intersection are defined by lack of severe KL filled fracturing.

Table A2 - 49. Intersections OL-BFZ160 at drill core. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR45 178.09 195.36 46 183.60 184.07

142




37.4 42.0 44.2



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR45 178.09 195.36 176.02 180.51 0.6

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-KR45

GSIwidth

143

OL-BFZ161



OL-BFZ161 is a subhorizontal potential fault zone with an approximate orientation of 145/16º. The modeled dimensions of this feature are ca. 2650 x 500 m. The zone is initially based on 3D reflection seismics: reflective features at the depth of ca. 730 – 780 m in the 2006 survey and 1050 – 1300 m in the 2007 survey were combined into a single unit. The zone intersects drillhole OL-KR4 at the depth of ca. 808 – 810 m and is characterised by intense fracturing, a few slickenslided fractures, pervasive illitisation and fracture-controlled kaolinitisation.



m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR4 808.30 809.95 65 808.30 809.95

144

Figure A2 - 40. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ161. The interpreted GSI-value of the deformaion zones core is 65.



39.8 41.7 46.1



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR4 808.30 809.95 808.30 809.95 1.0

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-KR4

GSIwidth

145

OL-BFZ175



OL-BFZ175 is a gently dipping fault zone with an approximate orientation of 150/27º. The zone is based on MAM results with a grounding in OL-KR11 at the depth of 418 m. It combines the following drillhole sections: OL-KR11 413.08 – 413.27 m (RiIII), OLKR42 297.99 – 298.36 (BFI), OL-KR46 411.7 – 412.17 (BFI), OL-KR47 220.87 – 221.50 (BFI) and OL-KR9 547.74 – 549.23 (RiIII). The core intersections are typically characterised by slickenside fractures with a moderate dip to the SSE. Geologically and geophysically the zone is not very significant. However, occasionally P-wave and hydraulic anomalies are related to it. The fault is located in the eastern part of the site as a possible extension or an extra splay of OL-BFZ020B (See Figure 9-34).



m_from


m_to

Core

GSI

Core

m_from

Core

m_to

Obs.

OL-KR9 547.74 549.23 68 547.74 549.23

OL-KR11 413.08 413.27 53 413.08 413.27

OL-KR42 297.03 302.67 -- No data

OL-KR44 804.66 812.28 60 808.50 808.98

OL-KR46 411.68 412.17 46 411.66 412.06

OL-KR47

OL-KR55

216.80

625.76

238.31

626.16

55

46

217.10

625.75

217.49

626.17

146




33.4 40.2 42.1


Hole_id

Geological intersection Geological intersection Core Core Distance btw

m_from m_to m_from m_to transm and

recvr

OL-KR9 547.74 549.23 547.74 549.23 1

OL-KR11 413.08 413.27 413.08 413.27 1

OL-KR42

OL-KR44

297.03

804.66

302.67

812.28

297.99

808.507

298.36

808.987

0.6

0.6

OL-KR46 411.68 412.17 411.7 412.17 0.6

OL-KR47 216.8 238.31 220.87 221.5 0.6

OL-KR55 626.76 626.16 624.49 625.09 no data

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-

KR

46

OL-

KR

55

OL-

KR

11

OL-

KR

47

OL-

KR

44

OL-

KR

54

GSIwidth

147

OL-BFZ214


The interpreted GSI value for OL-BFZ214 is 40 and determined Young’s module is 28.6 GPa. No seismic data were available from drillhole intersections and determined Young’s modulus for OL-BFZ0214 is the average value of all determined brittle deformations zones. Geological description of OL-BFZ214 is following (Aaltonen et al. 2010):

This zone is modelled by combining the long highly fractured section at the lower end of OL-KR47 and a major bounding lineament north of Olkiluoto island. The lineament has been detected by acoustic soundings. Based on fracture intensity and remarkable core loss the main core of the fault is fixed at 926.74 – 927.2 although there are no oriented fracture data.

OL_KR47_BFI_82852_100876: This is a very long brittle fault intersection that may be composed of several independent fault intersections blending to each other. The whole drillcore from 828.53 m downwards is fractured by slickensided fractures (194 of 499 fractures logged), and therefore it is impossible to defined stricter outer borders to the intersection(s). The natures of the several fault intersection cores are quite similar suggesting that they may be of same origin though. No borehole image exists and there is practically no oriented sample of the core sections, so their same/different attitude can not be verified. There are three common fracture directions, counted over the whole length of the intersection. The dominant is dipping to direction 180 degree with dip of ~45 degrees (almost parallel to foliation). One fracture direction is almost vertical 80-90 degrees dip with a strike 360/180. Third fracture direction dips to direction 230 degrees with a dip of ~40 degrees. The intersection locates in variable rocks, PGR from start to ~868 m, continuing with VGN, intersected by few short PGRs to the end of the drillhole at 1008.76 m. The uppermost fault core locates at 896.52 - 897.55 m and consist of frequent sl. fractures and at 896.82 - 896.89 m compacted fault breccia. The breccia has been compacted with unidentified white mineral (possibly nacrite?) The first core seems to dip to direction 170 degrees with a dip of 50 degrees. The second fault core locates at 915.42 - 915.83 m and consist of fault breccia with clay, graphite and pyrite. The attitude of the core is unknown. Third fault core locates at 926.74 - 927.20 m and consist of fault breccia. There are also several other less pronounced section of intensive fracturing and minor breccia (eg. 925.93 m. 956.60 m and 957.00 m). The core zones are altered with strong graphitization, chloritization and locally sulphidization and weak illitization. The zones of influence are mainly unaltered or weakly altered. The PGR sections below 959 m contains locally core discing.

148



m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR47 828.53 1008.76 40 926.74 927.20


GS

I

core

wid

th0 0

20 0.8

40 1.6

60 2.4

80 3.2

OL-KR47

GSIwidth

149

OL-BFZ219



The intersection is composed of VGN and PGR. PGR sections have old welded calcite bearing fractures. Fractures have dip direction towards NW with a nearly horizontal dip. The intersection contains 8 slickenside surfaces but the orientation of the striation varies. Some of the fractures are water -conducting. These fractures contain kaolinite and grayish clay infillings. The intersection contains ca 40 joints, with 13 fractures/0.7 m (576.21-576.91). Some mechanical fracturing has occurred during the drillings.



m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR25 517.55 578.00 51 572.24 572.50

150




28.1 28.8 29.4



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR25 517.55 578.00 571.70 572.50 1.0

GS

I

core

wid

th

20 0

40 1

60 2

80 3

OL-KR25

GSIwidth

151

APPENDIX 3 Analysed technical rooms levels

Figure A3-1. Analysed technical rooms in demonstration tunnel level.

152

Figure A3-2. Analysed technical rooms in technical rooms level.

153

Figure A3-3. Analysed technical rooms in -457 level.

154

geometrical and mechanical properties of the fractures and ... · in this report, the rock...

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