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Geological and Geotechnical MappingProcedures in use in the ONKALO

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POSIVA OY

Olki luoto

FI-27160 EURAJOKI, F INLAND

Phone (02) 8372 31 (nat. ) , (+358-2-) 8372 31 ( int. )

Fax (02) 8372 3809 (nat. ) , (+358-2-) 8372 3809 ( int. )

June 2015

POSIVA 2015-01

Juhani Norokal l io

POSIVA 2015-01

June 2015

POSIVA OY

Olki luoto

FI-27160 EURAJOKI, F INLAND

Phone (02) 8372 31 (nat. ) , (+358-2-) 8372 31 ( int. )

Fax (02) 8372 3809 (nat. ) , (+358-2-) 8372 3809 ( int. )

Juhani Norokal l io

Posiva Oy

Geological and Geotechnical MappingProcedures in use in the ONKALO

ISBN 978-951-652-243-5ISSN 1239-3096

Tekijä(t) – Author(s)

Juhani Norokallio, Posiva Oy

Toimeksiantaja(t) – Commissioned by

Posiva Oy

Nimeke – Title GEOLOGICAL AND GEOTECHNICAL MAPPING PROCEDURES IN USE IN THE ONKALO

Tiivistelmä – Abstract

This report describes and evaluates the geological and geotechnical mapping procedures used in the ONKALO underground rock characterization facility. The described procedures will also be applied in the repository tunnels. At present, the geological mapping procedures used in ONKALO are divided into three different stages: round mapping, systematic mapping and supplementary studies. The main purpose of the round mapping stage is to obtain geological data for the geotechnical assessment of the rock mass for excavation purposes, especially for the design of tunnel reinforcement. At this stage, the round is also 3D-photographed. The round mapping is performed from below the shotcreted roof of the previous round. The systematic mapping takes place soon after the roof of the round has been shotcreted. Most of the geological data is gathered during this phase and after the mapping, all observations are measured with a tachymeter to obtain precise location data. The supplementary studies comprise several mapping phases, which include mapping of the significant fractures (Tunnel Crosscutting Fractures - TCF), detailed mapping and descriptions of deformation zone intersections, as well as petrological and mineralogical sampling. Many of these features are already recognized during the round and systematic mapping, but their detailed definition and description is completed during this last mapping phase. Over time, several improvements have been made to the mapping procedures used in ONKALO. The current mapping methods give both detailed information and an extensive view of the geology of the excavated areas. However, the development of the mapping procedure is still undergoing as described at the end of this report.

Avainsanat - Keywords

ONKALO, geological mapping, mapping procedures, round mapping, systematic mapping, supplementary studies, evaluation. ISBN

ISBN 978-951-652-243-5 ISSN

ISSN 1239-3096 Sivumäärä – Number of pages

54 Kieli – Language

English

Posiva-raportti – Posiva Report Posiva Oy Olkiluoto FI-27160 EURAJOKI, FINLAND Puh. 02-8372 (31) – Int. Tel. +358 2 8372 (31)

Raportin tunnus – Report code

POSIVA 2015-01

Julkaisuaika – Date

June 2015

Tekijä(t) – Author(s)

Juhani Norokallio, Posiva Oy

Toimeksiantaja(t) – Commissioned by

Posiva Oy

Nimeke – Title

ONKALOSSA KÄYTETTÄVÄT GEOLOGISET JA GEOTEKNISET KARTOITUS-MENETELMÄT

Tiivistelmä – Abstract

Tämä raportti käsittelee maanalaisessa tutkimustilassa, ONKALOssa, käytettäviä geologisia ja geoteknisiä kartoitusmenetelmiä, sekä niihin liittyviä kehitystarpeita. Raportissa kuvattuja kartoitusmenetelmiä tullaan soveltamaan myös loppusijoitustiloissa. Tämänhetkisen käytännön mukaan geologinen kartoitus suoritetaan kolmessa eri vaiheessa, jotka ovat katkokartoitus, systemaattinen kartoitus sekä täydentävät tutkimukset. Ensimmäisen vaiheen eli katkokartoituksen tärkeimpänä tehtävänä on määritellä kalliolaatu ja tämän avulla antaa tietoa suunnittelun ja louhinnan tarpeisiin lähinnä suunniteltaessa työnaikaista lujitusta. Katkokartoituksen aikana kalliopinnat myös 3D-kuvataan. Kartoitus tehdään aina edellisen, jo lujitetun katkon puolelta. Systemaattisen, eli toisen vaiheen kartoituksen aikana kerätään suurin osa geologisesta aineistosta. Systemaattinen kartoitus tehdään katkoittain, heti katon lujittamisen jälkeen, ja kartoitus käsittää myös lattian. Kartoituksen jälkeen kaikki havainnot mitataan takymetrillä, jolloin havainnoille saadaan tarkka paikkatieto. Täydentävillä tutkimuksilla täydennetään aiemmista kartoitusvaiheista saatua tietoa mm. laatimalla yksityiskohtaiset kuvaukset havaituista deformaatiovyöhykelävistyksistä ja merkittävistä (mm. koko tunneli-profiilia leikkaavista) raoista. Myös petrologisten ja mineralogisten näytteiden otto suoritetaan tarvittaessa osana täydentäviä tutkimuksia. ONKALOssa suoritettava geologinen kartoitus on kehittynyt nykyisen kaltaiseksi useiden muutosten ja kehitystarpeiden tuloksena. Nykyisellään se antaa laajan, mutta myös yksityiskohtaisen kuvan louhittujen tilojen geologiasta. Kehitystyö jatkuu ja siitä esimerkkinä raportin lopussa esitetyt muutamat kehitysehdotukset.

Avainsanat - Keywords

ONKALO, geologinen kartoitus, geotekninen kartoitus, kartoitusmenetelmät, katkokartoitus, systemaattinen kartoitus, täydentävät tutkimukset, kehittämistarpeet. ISBN

ISBN 978-951-652-243-5 ISSN

ISSN 1239-3096 Sivumäärä – Number of pages

54 Kieli – Language

Englanti

Posiva-raportti – Posiva Report Posiva Oy Olkiluoto FI-27160 EURAJOKI, FINLAND Puh. 02-8372 (31) – Int. Tel. +358 2 8372 (31)

Raportin tunnus – Report code

POSIVA 2015-01

Julkaisuaika – Date

Kesäkuu 2015

1

TABLE OF CONTENTS

ABSTRACT

TIIVISTELMÄ

1 INTRODUCTION .................................................................................................... 3 2 CURRENT MAPPING PRACTICE .......................................................................... 5

2.1 Mapping procedures ....................................................................................... 5 2.1.1 Round mapping ........................................................................................... 5

2.1.1.1 Rock mass quality (Q classification).................................................... 6 2.1.1.2 Main fracture orientations and overall geologic description ................ 8

2.1.2 Systematic mapping .................................................................................... 8 2.1.2.1 Rock mass quality (Q classification).................................................... 9 2.1.2.2 Friction Angle and Waviness Angle................................................... 10 2.1.2.3 Lithology ............................................................................................ 11 2.1.2.4 Ductile deformation ........................................................................... 14 2.1.2.5 Brittle deformation ............................................................................. 14 2.1.2.6 Number of fractures and fracture spacing ......................................... 15 2.1.2.7 Fracture length .................................................................................. 15 2.1.2.8 Fracture filling width .......................................................................... 15 2.1.2.9 Alteration ........................................................................................... 15 2.1.2.10 Water leakages ............................................................................. 16

2.1.3 Supplementary studies .............................................................................. 16 2.1.3.1 Tunnel crosscutting fractures (TCF) .................................................. 16 2.1.3.2 Deformation zone intersections ......................................................... 18 2.1.3.3 Other supplementary studies ............................................................ 19

2.1.4 Mapping of deposition holes ..................................................................... 19 2.2 Description of the mapping parameters ........................................................ 21

3 EVALUATION AND DEVELOPMENT OF MAPPING PROCEDURE ................... 35 3.1 Round mapping ............................................................................................. 35 3.2 Systematic Mapping ...................................................................................... 35

3.2.1 Leucosome content ................................................................................... 35 3.2.2 Type of the mineralogical alteration .......................................................... 35

3.3 Supplementary studies ................................................................................. 35 3.3.1 Deformation zone intersections ................................................................. 35

3.3.1.1 Water leakage ................................................................................... 35 REFERENCES: ............................................................................................................ 39 4 APPENDICES: ...................................................................................................... 41

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1 INTRODUCTION

This report presents current geological and geotechnical mapping procedures for all the excavated areas in the ONKALO, e.g. the access tunnel, the four demonstration tunnels and the technical rooms, together with brief geological descriptions (Chapter 2). For more detailed geological descriptions, see Nordbäck (2013). Some considerations regarding the development of the mapping parameters and procedures are presented at the end of the report (Chapter 3).

The excavation of the ONKALO underground rock characterisation facility began in September 2004 and by the beginning of April 2012 approximately 4900 m of the tunnel had been excavated, in addition to the demonstration tunnels and the technical rooms. Its construction has been performed as a three-stage process comprising: (1) the drilling of probe holes (15–26 m in length); (2) pre-grouting if required; (3) the excavation of three to four rounds, each 4–5 m in length (using drill and blast). After chainage 4400 the roof is shotcreted after every blast.

Against this background, the geological and geotechnical mapping procedures in the ONKALO have been revised and improved several times to meet the different demands of excavation and research.

Several different classification systems for defining the geotechnical properties of hard rock have been developed, mainly due to the wide variety of properties that the bedrock exhibits. Posiva has chosen three of these classification systems and uses them concurrently when assessing the rock properties, in order to obtain a wide diversity in the geotechnical classification. The three systems that Posiva uses are the Rock Quality Designation (RQD) of Deere et al. (1967), the Q classification system of Barton et al. (1974), Grimstad & Barton (1993) and Barton (2002) and the RG classification (Rakennusgeologinen kallioluokitus) of Korhonen et al. (1974) and Gardemeister et al. (1976). The Q classification system is the most widely used one in the world and is the main classification scheme used in the ONKALO tunnel. The RG classification system was developed for Finnish conditions and is therefore a good supplement to the other systems.

The principles of naming rocks at Olkiluoto have been laid out in the working report “A system of Nomenclature for Rocks in Olkiluoto" (Mattila 2006). This nomenclature, which was developed in particular for the migmatitic gneisses at Olkiluoto, recognises three groups: veined gneiss, stromatic gneiss and diatexitic gneiss (Kärki & Paulamäki 2006). The pervasive foliation, which is typical of the Olkiluoto site, is classified using a unique classification system developed by Milnes et al. (2006), which takes into account the intensity and type of the foliation. Deformation zones intersecting the ONKALO are described using the methodology explained in Milnes et al. (2007) and used in the geological modelling of the Olkiluoto site (Paulamäki et al. 2006, Mattila et al. 2008). This methodology is derived from the fault rock classification system proposed by Sibson (1977) and further developed by Scholz (2002) and has proved to be particularly suitable for the different types of deformation zones occurring in the high-grade metamorphic rocks at Olkiluoto.

At present, the geological and geotechnical mapping takes place in three different stages; round mapping, systematic mapping and supplementary studies. The first stage,

4

round mapping, is a geotechnical mapping procedure to assess the rock quality soon after excavation. Systematic mapping is the main geological mapping stage, and this is when the main part of the geological information is obtained. The supplementary studies include, for example, the definition of Tunnel Crosscutting Fractures (TCF, see definition below, Section 2.1.3.1), the recognition and description of deformation zone intersections, and water leakage mapping.

This report is divided into three chapters, where Chapter 1 is the introduction and Chapter 2 describes current, i.e. existing, mapping practices with some examples. Descriptions of the mapping parameters are also included in Chapter 2. Future development needs are discussed in Chapter 3, in the light of experience gathered by the mapping teams to date, and some changes to these practices are proposed. The Appendices contain the determination tables and spreadsheets at present in use for mapping purposes, in association with the three types of mapping which are being carried out: Description of the various Q parameters are presented in Appendix 1; round mapping in Appendix 2; systematic geological mapping in Appendices 3 and 4; and supplementary studies (e.g. characterisation of deformation zone intersections), in Appendix 5. Also, the abbreviations used for fracture-filling minerals used in the systematic geological mapping of the ONKALO access tunnel are presented on Appendix 6.

Several improvements have been made to the mapping procedure as well as to the mapping spreadsheets since the first report describing and explaining the geological and geotechnical mapping practice used in the ONKALO access tunnel (Engström & Kemppainen 2008) was published. These changes are presented and discussed in the current report and also further development ideas are presented. The procedures associated with round mapping, systematic mapping and geological deformation zone mapping are presented in detail in the following instructions: POS-001497 Onkalon geologinen kartoitus, 1. vaihe (round mapping), POS-001995, ONKALON geologisen kartoituksen suorittaminen, toinen vaihe (systematic mapping) and POS-016468 geologisen deformaatiovyöhykkeen kartoitus ONKALOssa (deformation zone mapping).

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2 CURRENT MAPPING PRACTICE

The guidelines for geological and geotechnical mapping to be used in the ONKALO access tunnel were set out and published in the Underground Characterisation and Research Programme (UCRP) (Posiva 2003). This report stated that the mapping should be carried out in three steps: Step 1 - tunnel face mapping; Step 2 - tunnel window mapping; and Step 3 - supplementary studies. The current mapping practice follows these guidelines, although the content of each step has been revised and renamed during the construction of the ONKALO access tunnel; and further changes have been made in the mapping procedure since the previous evaluation report (Engström & Kemppainen 2008). In addition, development of the mapping procedure is still taking place, in preparation for the construction of the final repository tunnels. The main aim is to achieve a more accurate and detailed geological model for the ONKALO area, as well as to optimize the procedures for mapping the repository rooms.

2.1 Mapping procedures

The geological and geotechnical mapping procedures currently used in the ONKALO tunnels have been specially developed by Posiva, to obtain as much information as possible from the tunnel in the time that is available for research, as excavation and mapping are required to operate simultaneously. The total time necessary for the mapping of one round (ca. 5 m section of tunnel) obviously varies depending on the tunnel profile, the rock quality and the level of fracturing. During excavation, the walls, roof and floor of the tunnel are mapped, whereas the tunnel face is only mapped for completely excavated tunnels and rooms. The geological and geotechnical mapping is divided into three separate stages, which are carried out in a manner which affects the normal tunnel excavation procedures as little as possible. The three mapping stages and the approximate times required for each are:

- Round mapping (duration ~0.5-1 h per round) (Section 2.1.1)

- Systematic mapping (duration ~1-3 h per round) (Section 2.1.2)

- Supplementary studies (duration ~0.5-2 h per round) (Section 2.1.3).

In addition to the various tunnels, geological and geotechnical mapping will be carried out in deposition holes. The procedure (described in Section 2.1.4) has been developed during the construction of the demonstration facilities and the associated experimental deposition holes, and is still likely to go through some further development.

2.1.1 Round mapping

The round mapping is performed as soon as possible after each excavation round, its main purpose being to obtain geological data for the geotechnical assessment of the rock mass for excavation purposes. Therefore, the main parameters to be obtained in the round mapping are the six parameters required by the Q classification system (see Section 2.1.1.1). These parameters are gathered from fractures more than 1 m in length. Since 2011 the round mapping has been performed below the shotcreted roof of the previous round from the tunnel face. The shotcreting of the last excavated round is carried out soon after the round mapping procedure, so this is only opportunity for

6

obtaining observations from the tunnel roof. It is, therefore, very important to notice deformation zone intersections (see Section 2.1.3.2.) and long fractures (see Section 2.1.3.1.) at this stage and to measure them with a tachymeter. The locations of the measured fractures are also denoted in the Remarks field of the mapping data sheet by the letter K (indicating the roof), O (indicating the right wall) or V (indicating the left wall). This helps those who need to make use of the geological data, for example to investigate fracture densities, but have not experienced the situation in the tunnel.

In addition to the Q parameters, deformation zone intersections and long fractures, observations of the main fracture orientations (fractures over 1m in length), rock types, grain size variations and water leakages are also included with the mapping procedure (see Section 2.1.1.2).

A detailed description of the various parameters used in the round mapping is given in Section 2.2 and the spreadsheet used for the round mapping is attached as Appendix 2.

2.1.1.1 Rock mass quality (Q classification)

The Q classification is performed for each and every round that is excavated and Q values are determined separately for the left wall, the right wall and the roof of the tunnel. The data obtained are plotted on a graph developed by Grimstad & Barton (1993) to assess the amount and type of support required for the investigated tunnel section (Figure 2-1). The graph is a tool to assist in decision making for the excavation team, when considering whether temporary tunnel support is required.

7

Figure 2-1. Diagram used for estimating the need for tunnel support in the ONKALO access tunnel (from Grimstad & Barton 1993).

The Q classification scheme (Barton et al. 1974; Grimstad & Barton 1993) is used in order to determine the rock mass quality in the ONKALO tunnel. A first assessment of the rock mass quality is carried out during the round mapping stage, but the final evaluation of the rock mass quality is carried out during the systematic mapping (see Section 2.1.2). A description of the various Q parameters is presented in Appendix 1, and the spreadsheet used for processing the data in Appendix 4 (See Table 2-2 for descriptions). The Q parameters are defined for each excavated round of the ONKALO tunnel and are calculated using the following equations (Barton et al. 1974; Grimstad & Barton 1993):

SRF

J

J

J

J

RQDQ w

a

r

n

** and a

r

n J

J

J

RQDQ *´

The rock quality designation (RQD) is defined on the basis of a visual estimation of the total amount of fracturing in the tunnel for each mapped section. Also, the other parameters are estimated visually. These parameters are: the joint set number (Jn), the joint roughness number (Jr), the joint alteration number (Ja), the joint water reduction number (Jw) and the stress reduction factor (SRF).

1) Unsupported

2) Spot bolting

3) Systematic bolting

6) Fibre reinforced shotcrete and bolting 9-12 cm

7) Fibre reinforced shotcrete and bolting 12-15 cm

8) Fibre reinforced shotcrete > 15 cm

(Grimstad and Barton, 1993)

REINFORCEMENT CATEGORIES

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2.1.1.2 Main fracture orientations and overall geologic description

In the round mapping phase the orientations and fracture profiles of main fractures exceeding 1 m in length are observed (for details see Appendix 2). The function is not to observe all fractures more than 1 m in length but as many as needed to obtain a good overview of the geological properties. More detailed mapping is carried out later in the systematic mapping phase. If some of the fractures continue from one wall to the other (also seen on the tunnel face), or if they crosscut the roof, they are accurately measured with a tachymeter to obtain their exact locations.

At this stage, the round is also digitally photographed and scanned (systematic digital imaging.) Previously, photographs were obtained using two digital cameras to obtain stereographic images, but the current method, which has already been used in demonstration tunnels 3 and 4, is to use one camera and transform 2D digital data into 3D using a 3D measurement application.

During the round mapping a small sketch is drawn in the spreadsheet for fractures that can be traced from one wall of the tunnel to the other (passing through the face of the tunnel). The sketch illustrates the trace of the fracture on both walls and on the face of the tunnel, thus preventing the same fracture being given a different name on each wall of the tunnel in subsequent excavated sections, where it might not be possible to see the fracture trace in the face of the tunnel. This process also helps distinguishing these fractures later when the systematic mapping is performed. A sketch is also made if a fracture continues from one excavated round to another, even if the fracture trace follows only one of the walls or if the fracture is measured with a tachymeter.

In the round mapping phase, the rock type (see Section 2.1.2.3.) as well as grain size variations are determined from both walls and from the roof. Grain size is placed into one of four different categories: 1) <1 mm. 2) 1-5 mm. 3) 5-50 mm and 4) >50 mm. Water leakages are also observed, but the amount of flow is measured later (see Sections 2.1.2.10 and 2.1.3.3).

2.1.2 Systematic mapping

The systematic geological mapping was originally performed tens to hundreds of metres behind the active tunnel face, commonly in 10 m long sections (i.e. two rounds). The current practice is that after the roof of the last excavated round has been shotcreted, the tunnel walls and floor are cleaned to check if any remains of explosives could be found after blasting. This revision provides an opportunity of mapping the tunnel floor, and the systematic mapping is now carried out round-by-round in 3-6 m long sections. The spreadsheet used in the systematic geological mapping is attached as Appendix 3. All mapping data are collected in a single table sheet and the structural elements are described as single observations and marked on the tunnel wall with corresponding numbers. The table sheet includes designation details, such as the chainage from the beginning to the end of the mapped section and other tunnel-specific data. For each mapped section, a detailed lithological description is made. The structural observations include, in addition to the fracture-specific data, fields for rock type, foliation, folding, deformation phase and samples. The fracture attribute data include orientation, trace length, displacement, surface morphology, filling materials, aperture, termination,

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undulation, water leakages and, for fractures with discernible movement, lineation (or a so-called F vector). All fractures with trace lengths greater than 25 cm are measured.

2.1.2.1 Rock mass quality (Q classification)

The Q parameters observed in the round mapping phase are occasionally redefined during the systematic mapping stage, based on the detailed fracture data collected from all fractures with a trace length of 1 m or greater. For each section, the Q and Q' values are calculated for the 1st quarter, 3rd quarter, average and median, where the joint roughness (Jr) and alteration (Ja) numbers alter. The median values are then used to determine the rock mass quality (Q and Q' values) for the investigated section, as shown in Figure 2-2 and Appendix 4.

The joint set number (Jn) is first estimated visually, but later verified from stereograms, and the Jr and Ja numbers are calculated (1st quarter, 3rd quarter, average and median), (see Table 2-2 and Appendix 4). The other three parameters (RQD, Jw and SRF) are also re-evaluated during this detailed mapping, and form the basis for the design of the permanent tunnel support for the ONKALO tunnel.

Figure 2-2. Map of rock mass quality (Q value) variations using Gemcom Surpac 3D program, ONKALO access tunnel chainage 3580-3670.

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2.1.2.2 Friction Angle and Waviness Angle

For each joint set, the number of fractures, mean Jr and Ja numbers, mean orientation, friction angle, waviness angle and mean length are calculated using the Dips program and Excel (Appendix 4). All fractures less than 1 m in length are excluded from these calculations. The friction angle (ø´) takes into account the ratio between the mean value of the roughness (Jr) and alteration (Ja) numbers in the fractures, calculated using the following equation (Barton 2002):

o

a

r

J

J)(tan ' 1

The friction angle varies from the extremes of clean-and-rough-and-discontinuous (79°) to slickensided-and-thinly-clay-filled (2°) (Barton 2002).

The waviness angle is calculated using the simplification that the fracture undulates like a right-angled triangle, as shown in Figure 2-3; accordingly, the following equation is used in the calculation:

)50

)/((tanangle Waviness 1

cm

mcmUndulation

Figure 2-3. Illustration showing the assumptions used in the calculation of the waviness angle.

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2.1.2.3 Lithology

The mapping of lithology in the ONKALO tunnel is carried out according to the principles laid down in the working report “A system of Nomenclature for Rocks in Olkiluoto" (Mattila 2006). The gneisses at Olkiluoto usually have a migmatitic appearance and, therefore, the descriptive terminology of migmatites (Wimmenauer & Bryhni 2007) provides a useful basis. In the migmatites, the leucosome is the leucocratic, light-coloured portion, usually showing magmatic textures. Mesosome is the name given to the mesocratic (light grey coloured) part of the rock, showing metamorphic textures, in this case mostly mica gneiss. Melanosome is the melanocratic (dark grey to black) part, which occurs as biotite-rich stripes (schlieren) or narrow bands in the migmatite.

On the basis of their migmatite structure, the migmatitic gneisses at Olkiluoto can be divided into three groups: veined gneiss (VGN), diatexitic gneiss (DGN) and stromatic gneiss (SGN) (Kärki & Paulamäki 2006). The leucosome of the veined gneiss occurs as discontinuous streaks and lenses with some features similar to large-scale augen structures. Planar, sheet-like leucosome bands and layers characterise the stromatic gneiss. The migmatite structure of the diatexitic gneiss is irregular, and the leucosome occurs as diffuse patches in the mesosome. The amount of the leucosome in all migmatitic gneisses varies from 20% to more than 80%, the average lying within the range 20–40%.

The lithological mapping in the ONKALO tunnel is performed during the systematic mapping phase. A short description of the lithology for every mapped section can be found in the Notes line at the heading of the mapping sheet (see Table 2-3, and Appendix 3). The classification of the various rock types is defined on a visual basis and this poses a challenge, especially when deciding on the types for the different migmatitic structures in gneisses. This is due to the gradational changes in the structures associated with these migmatitic gneisses. An example of the results of lithological mapping in the ONKALO access tunnel is shown in Figure 2-4.

Figure 2-4. Lithological units in the ONKALO access tunnel at chainages between 3580–3670.

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The veined gneiss consists of a foliated mica gneiss mesosome and discontinuous, granitic leucosome streaks, lenses and boudins, around which the mesosome foliation combines (Figure 2-5A). The greyish mica gneiss mesosome is small- to medium-grained, relatively homogeneous and the laths of mica minerals are aligned, forming a foliation. The leucosome component (10–60%) is whitish or occasionally reddish, medium- to coarse-grained, non-foliated granite or pegmatitic granite. The veined gneiss is usually distinctly banded (Figure 2-5B), and folding and boudinage of leucosome veins is also present.

The veined gneiss typically passes gradationally into diatexitic gneiss. Like the veined gneiss, the diatexitic gneiss consists of a mica gneiss mesosome and a pegmatite granite leucosome, but it usually has a much higher proportion of leucosome and a larger grain size than the veined gneiss. The diatexitic gneiss has irregular, schlieren-like structures and a nebulitic appearance (Figure 2-5C). The mesosome is usually medium-grained and the rock is in some places weakly banded. Folding is occasionally observed in the diatexitic gneiss.

The stromatic gneiss (SGN) is composed of foliated mica gneiss mesosome and granitic leucosome veins, aligned parallel to foliation planes. The greyish mica gneiss mesosome is small- to medium-grained and relatively homogenous and the laths of mica minerals are aligned, forming a foliation. The leucosome or neosome component is whitish or occasionally reddish, medium- to coarse-grained, non-oriented granite or pegmatitic granite forming planar sheet-like bands and veins (Figure 2-5D).

In addition to the gneissic rocks, pegmatitic granite (PGR) is included in the main rock types in Olkiluoto. The pegmatitic granite is a coarse-grained rock type that typically contains large feldspar phenocrysts. The PGR has a pale whitish-greyish or reddish-pinkish colour and the wider sections and dykes enclose mafic melanosome patches (biotite schlieren) (Figures 2-5E and 2-5F). The pegmatitic granite is present in many places in the tunnel as dykes and veins of various sizes. The dykes are mostly parallel to the foliation of the surrounding gneisses, but some are cross-cutting. The pegmatitic granite also appears as larger bodies that show an indefinite contact with the surrounding gneisses, which often differs from the more distinct lithological contacts encountered during drillcore logging.

In addition to these main rock types, this part of the tunnel also contains countless mica gneiss (MGN), quartz gneiss (QGN) and mafic gneiss (MFGN) inclusions and lenses, which vary considerably in shape and size. The mica gneiss is typically fine-grained and consists of quartz, biotite and feldspars in variable proportions. The protolith of the mica gneiss is thought to be psammitic. More calcic, skarn-like variants also exist, and they can be identified by their layered, rimmed appearance, where the different layers probably represent different sedimentary protoliths. The inclusions are very often elongated parallel to the foliation and are commonly more densely fractured than the surrounding rock (Figure 2-5G). Typically, the inclusions contain planar, smooth fractures with calcite and pyrite fillings.

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Figure 2-5. Representative photographs of the main lithologies encountered in the ONKALO access tunnel. A) Moderately-banded VGN with moderate amounts of thin PGR neosome veins, chainage 4475-4480, view towards SW. B) Distinctly-banded VGN with whitish coarse-grained PGR neosome veins, chainage 4045, view towards NE. C) The diatexitic gneiss at chainage 3645-3650 has irregular, schlieren-like structures and a nebulitic appearance, view towards NE. D) Symmetrically-banded SGN at chainage 3595, view towards S. E) Whitish, coarse-grained PGR in the roof of the tunnel at chainage 4445, view toward S. F) Coarse-grained, reddish PGR at chainage 3775, view towards N. G) Coarse-grained, reddish PGR with abundantly fractured MGN inclusions at chainage 3935, view towards NE.

A B

DC

E

G

F

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2.1.2.4 Ductile deformation

The geological mapping of ductile features includes observations of foliations, fold axes and fold axial planes. These features are mapped during the systematic mapping phase and the data are collected on the same data sheet as the fracture data (Appendix 3). In addition to the systematic foliation mapping, intensively-foliated deformation zones are investigated in more detail during the supplementary studies, with the aim of distinguishing high-grade ductile deformation zones (HGI, see Section 2.1.3.2).

The foliation is classified according to a system that takes into account the intensity and type of foliation (Milnes et al. 2006). The intensity is classified from 0–3, corresponding to intensity values from non-existent to high. The different foliation types are gneissic (GNE), banded (BAN), schistose (SCH), irregular (IRR) and massive (MAS). The intensity of foliation in the gneissic, banded and schistose types is described using values 1–3. The intensity value for irregular and massive types is 0.

2.1.2.5 Brittle deformation

The systematic fracture mapping is the most detailed and time-consuming part of the geological mapping process in the ONKALO tunnel. The fracture attribute data includes orientation, number of fractures clustered together, the space between these clustered fractures, trace length, displacement, the surface and fillings, aperture, termination, undulation, main rock type for the fracture, water leakage from the fracture and lineation (or a so-called F vector) for fractures with any discernible movement. After the mapping, all observations are measured with a tachymeter to obtain precise data on fracture locations (Figure 2-6). These data are compatible with the Gemcom Surpac 3D program, the use of which is a considerable improvement from the early state of ONKALO mapping, when all fracture and foliation observations were drawn as a sketch on paper and later digitised into a scanned 3D tunnel point cloud using the Gemcom Surpac3D program.

Figure 2-6. Visualisation of the fracture data measured from demonstration tunnel 1 (ONK-TDT-4399-44) in the Gemcom Surpac 3D program. The red colour marks the left wall, the green the right wall and the blue colour marks the roof and the floor of the ONKALO tunnel.

Fracture data from demonstration tunnel 1 chainage 30-40

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2.1.2.6 Number of fractures and fracture spacing

Fractures within the same mapped section, having the same attribute data, can be considered to be clustered. Clustering of the fractures means that if two or more closely-spaced fractures have the same attribute data (orientation, roughness, fracture mineralogy, etc.), they are grouped together. However, to obtain the correct statistical attribute data, all fractures within these clusters are taken into account when the data are processed. The upper limit of fractures clustered together is 10 and the maximum distance between the fractures is 1 m. It is important to ensure that the attribute data are identical for all clustered fractures. This prevents the oversimplification of the mapping data and ensures a high standard in the systematic mapping procedures in the ONKALO access tunnel.

2.1.2.7 Fracture length

The minimum fracture trace length measured is 0.25 m, which was proposed in the previous evaluation report (Engström & Kemppainen 2008). This minimum limit is considered reasonable, since it is a real challenge for the geologist to observe all the short fractures during the mapping stage. Also, the difference between natural fractures and fractures induced by the process of excavation is difficult to distinguish when considering very short fractures (less than 0.25 m). As mentioned in the previous evaluation report, fewer than 10% of the fractures in chainage 0-2405 had a trace length of 0.24 m or less; the cut-off of 0.25 m is also reasonable in the light of discrete fracture network models (Engström & Kemppainen 2008).

2.1.2.8 Fracture filling width

The improved procedure for observing fracture filling width and the fracture filling minerals was introduced after the evaluation report (Engström & Kemppainen 2008). In the actual systematic mapping spreadsheet, there are columns for 12 main fracture filling minerals and their widths and a column for the total filling width. The improvement has increased the accuracy of the data collected from the tunnel and enhanced the modelling of individual fractures. It also makes comparison of data between the drillholes and the tunnel easier.

2.1.2.9 Alteration

According to the current geological model (Posiva 2012), the bedrock at Olkiluoto was subjected to extensive hydrothermal activity and local metasomatic alteration, which were linked to the tectonic and depositional evolution of the rock mass. Zones with high permeability have repeatedly acted as pathways for hydrothermal fluids. Weathering processes and the circulation of meteoric water have also contributed to the alteration of the bedrock. The main alteration types are kaolinisation and illitisation (formation of clay minerals), carbonatisation, graphitisation and sulphidisation. Some seritisation and epidotisation also occurs.

The geological mapping of the fracture-controlled alteration in the ONKALO access tunnel is based on the fracture minerals determined during the systematic geological mapping (Appendix 3). The fracture-controlled alteration comprises all alteration types mentioned above. If the rock mass itself shows signs of pervasive alteration, it is

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mentioned in the Notes line at the heading of the mapping sheet. (see Table 2-3, and Appendix 3).

2.1.2.10 Water leakages

Fracture-specific water leakages, where present, are also characterised during the systematic geological mapping, as well as during round mapping (Appendix 3). The characterisation of the water leakages is based on visual observations using the following classification (Lehtinen & Hirvonen 2007) (1-5):

1. The surface of a fracture is dry. 2. The surface of a fracture is damp. 3. The surface of a fracture is wet. 4. The surface of a fracture is dripping. 5. Water flowing from a fracture surface.

2.1.3 Supplementary studies

In the ONKALO, supplementary studies are carried out after round mapping and systematic mapping. The supplementary studies include mapping of the TCFs, detailed mapping and descriptions of deformation zone intersections, hydrogeological mapping as well as petrological, mineralogical and hydrogeochemical sampling. For practical reasons, all these studies are performed after the two main mapping stages.

2.1.3.1 Tunnel crosscutting fractures (TCF)

A tunnel crosscutting fracture (TCF) is defined as one continuous fracture, which crosscuts the whole ONKALO tunnel from one wall to the other, or has a length in excess of 20 m, if the fracture trace is visible only on one wall, in the floor and/or in the roof. A TCF corresponds to SKB’s definition of a Full Perimeter Intersection (FPI) fracture (Munier 2006).

TCFs observed in the ONKALO are measured and numbered in a sequential manner. The TCFs are accurately measured with a tachymeter to obtain the exact coordinates of the fracture traces (Figure 2-7). TCFs are already recognized during the round and systematic mapping, but their detailed definition and description is completed during this last mapping phase. Also, so-called M-fractures (Major Fractures) that have a significant length, but do not fulfil TCF criteria, are also measured and numbered in a sequential manner.

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The RG classification is used for the definition of TCF fractures, so that every fracture determined as a TCF is at least a RiI fracture zone (Table 2-1).

Table 2-1. Classification of fractured zones (Gardemeister et al. 1976).

RiI One or a few nearly planar fractures, with a length over 20 m or that clearly continue outside the tunnel.

RiII Fractured section, where fracture spacing is 10 to 30 cm.

RiIII Densely fractured section, where fracture spacing is less than 10 cm.

RiIV-Rk3 Fractured section, where fracture spacing is 10-30 cm. Clay filled fractures.

RiIV-Rk4 Densely fractured section, where fracture spacing is less than 10 cm. Clay filled fractures.

RiV Weak clay structure.

Figure 2-7. Visualisation of accurately measured TCFs using the Gemcom Surpac 3D program, ONKALO access tunnel chainage 3480-3500.

TCFs in chainage 3480-3500

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2.1.3.2 Deformation zone intersections

An important part of the supplementary studies and the geological mapping is the definition and description of deformation zones that intersect the tunnel (see the spreadsheet attached as Appendix 5). In the deformation zones, the bedrock is more fractured, deformed or altered than in the surrounding rock. The type of the deformation zone intersection is determined following the methodology explained in Milnes et al. (2007) and used in the geological modelling of the Olkiluoto site (Paulamäki et al. 2006, Mattila et al. 2008). This methodology is derived from the fault rock classification of Sibson (1977), which was further developed by Scholz (2002). The deformation zones can be divided into five categories, two with brittle and two with ductile character and one intermediate category (Table 2-2). Brittle deformation zones display cohesionless or low-cohesive deformation products: gouge, breccia, fractured rock and their partially- or wholly-mineralized equivalents, whilst the semi-brittle and ductile deformation zones display cohesive deformation products (Milnes et al. 2007).

Table 2-2. Classification of deformation zones (Milnes et al. 2007).

BJI Brittle Joint zone Intersection

The intersection shows no clear signs of lateral movement.

BFI Brittle Fault zone Intersection

The intersection shows clear signs of lateral movement.

SFI Semi-brittle Fault zone Intersection

The zone shows fine-grained cohesive deformation products (e.g. cataclasites, pseudotachylite and welded crush rocks), which are massive and structureless.

DSI Low-grade Ductile Shear/deformation zone Intersection

The zone shows fine-grained cohesive deformation products (e.g. mylonites and phyllonites), which are strongly laminated and/or foliated, and features which indicate that the deformation took place under low PT conditions (retrograde with respect to the high-grade metamorphic mineralogy of the wall rock).

HGI High-Grade ductile deformation zone Intersection

The zone shows medium to coarse-grained cohesive deformation products (e.g. blastomylonites), with strong foliation of banded or schistose type, and features which indicate that the deformation took place under high PT conditions (same as the wall rock, i.e. same high-grade metamorphic mineralogy).

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The location of every deformation zone intersection is determined at four different locations: on the left wall, on the right wall, on the roof and at a height of 1 m in the middle of the tunnel. The attributes mapped for every intersection are class, orientation, description, width of the whole zone and width of the core zone, water leakage and possible connections to previously mapped intersections. A detailed Q classification (see Section 2.1.1.1) is also carried out with specific Q values for pre-core, post-core and core zone, where the pre-core zone denotes the damage zone preceding the core zone (towards the entrance of the tunnel) and the post-core zone denotes the damage zone following the core zone (towards the face of the tunnel). The fracture characteristics for the main fractures within the intersection are also added from the fracture database.

2.1.3.3 Other supplementary studies

In the ONKALO tunnels, the hydrogeological mapping is carried out once a year to assess how water leakages in the tunnel change during construction. These data will be used to assist in the planning of research activities and to determine how well the grouting and shotcreting of the tunnel have performed. In addition, all new water-conductive fractures appearing during excavation are characterized in detail.

Also, Schmidt hammer testing of the major rock types of the excavated section is carried out during this supplementary mapping stage to measure the surface hardness and penetration resistance of the rock.

Petrological sampling is carried out systematically along the main tunnel up to chainage 4515, while mineralogical and hydrogeochemical sampling is carried out at specific locations.

2.1.4 Mapping of deposition holes

To date, a total of four experimental deposition holes have been constructed in demonstration tunnel ONK-TDT-4399-44. A geological mapping procedure has been devised for the experimental deposition holes, and will be applied for the actual deposition holes during the construction of the repository.

The mapping procedure used in deposition holes differs somewhat from the mapping procedure used for tunnels. No round mapping is carried out and the geological mapping starts directly from systematic mapping. Determining the exact locations of the observations made in a deposition hole is challenging, because the use of a tachymeter in a deposition hole is severely limited or even impossible. Therefore, deposition holes are laser scanned and the data used to obtain a detailed image, on which all observations are drawn, and later digitized into a 3D layout using the Gemcom Surpac program (See Figure 2-8). It is also possible to take digital photos, and by using a 3D measurement application, to determine exact coordinates for all the observations.

Supplementary studies are carried out where required. For example, deformation zones might already have been described, while mapping the tunnel hosting the deposition hole. In that case, a short description can be written in the notes field of the mapping

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sheet. If a previously unknown deformation zone were observed, a separate zone description would be required (see Section 2.1.3.2).

The mapping parameters are mainly the same as those used in tunnel mapping. The main difference is that the term HCF (Hole Crosscutting Fracture) is used instead of TCF. The HCF is defined as one continuous fracture, which crosscuts the whole perimeter of a deposition hole, or crosscuts both the floor and the apparent roof of the hole, i.e. a fracture without visible termination on the hole surface.

Figure 2-8. Visualisation of geological mapping data from experimental deposition hole 7 (EH7) using the Gemcom Surpac 3D program, ONKALO demonstration tunnel 1 (ONK-TDT-4399-44). Vertical HCF (red line) crosscutting the hole. Other fractures are shown as black lines.

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2.2 Description of the mapping parameters

A large number of geological and geotechnical parameters are recorded during the three mapping stages - the round mapping, the systematic mapping and supplementary studies - in the ONKALO. Descriptions and examples of these parameters are presented below.

The information in the data acquisition spreadsheets is divided into three sections: a heading (Table 2-3), a Q classification (Table 2-4) and the other structure parameters (Table 2-5). The two separate mapping stages, round mapping and systematic mapping, are described in adjacent columns to show which parameters are mapped during the different phases. Table 2-3 illustrates (with examples) the descriptive part of the data acquisition spreadsheet used for the two mapping stages. The spreadsheet for deformation zones is also similarly divided and is shown in Table 2-6.

Table 2-4 illustrates the rock mechanical (Q classification) part of the data acquisition spreadsheet for the two mapping stages. This Table also contains a column denoting which parameters are calculated and which are estimated during the mapping (see Appendix 4: spreadsheet used in the processing).

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Table 2-3. Description of the geological data acquisition spreadsheet headings used during mapping in the ONKALO access tunnel. A grey box indicates that that mapping parameter is used in only one of the two mapping stages.

Mapping parameter

Description Round Mapping Systematic Mapping Example Example

1-1 Site

Denotes where the mapping is done.

ONKALO ONKALO

1-2 Tunnel ID

Describes where in the tunnel the mapping is performed.

ONK-VT1 = ONKALO access tunnel ONK-KPE1 = ONKALO shaft access

ONK-VT1 = ONKALO access tunnel ONK-KPE1 = ONKALO shaft access

1-3 Round ID

Gives a unique ID code for the mapped section.

e.g. ONK-VT1-4800 e.g. ONK-VT1-4800

1-4 PL from Chainage where the mapping started.

4800 4800

1-5 PL to Chainage where the mapping ended.

4805 4805

1-6 Tunnel direction

Downward direction of the tunnel where the mapping is conducted.

0–360° 0–360°

1-7 Tunnel dip

Gradient of the tunnel predetermined by the profile used in the excavated section.

1:-10.00 = straight part of the access tunnel 1:-11.63 = curved part of the access tunnel

1:-10.00 = straight part of the access tunnel 1:-11.63 = curved part of the access tunnel

1-8 Tunnel profile

Numerical value for each type of tunnel profile.

523= demonstration tunnel 501= access tunnel

1-9 Arch span (m)

Arch span (based on excavation design) of the tunnel for the excavated/mapped round.

Numerical value, e.g. 8 m.

1-10 Wall height (m)

Wall height (based on excavation design) of the tunnel for the excavated/mapped round.

Numerical value, e.g. 4.5 m.

1-11 Mapping date/time

Date and time when mapping is performed. 1.3.2012 = 1 of March 2012 1.3.2012 = 1 of March 2012

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1-12 Geologist

Official abbreviation (acquired from TVO permit database) of the geologist and/or assistant who completed the mapping.

NJK = Juhani Norokallio RMAA= Emmi Eroma

NJK = Juhani Norokallio RMAA = Emmi Eroma

1-13 Page

The page number if several pages are used.

Numerical value Numerical value

1-14 Picture file

Name of picture file connected to spreadsheet.

File name File name

1-15 Checked

Date and official abbreviation of the geologist who checked the document.

4.3.2012 NJK 4.3.2012 NJK

1-16 Approved

Date and official abbreviation of the geologist who approved the document.

4.3.2012 ISAA 4.3.2012 ISAA

1-17 Notes Lithological and general geological description of the mapped section.

Intensively banded VGN with ~40% leucosome content. On the roof there is one longer gently dipping USL fracture and shorter subvertical KA filled fractures. The walls are slightly fractured.

Mainly VGN with a small MGN inclusion in the lower part of the right wall. Neosome content 20%. In the upper part of the right wall and in the roof VGN intensively veined.

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Table 2-4. Description of the Q value part of the geological data acquisition spreadsheet used during mapping in the ONKALO access tunnel. A grey box indicates that that mapping parameter is used in only one of the two mapping stages.

Mapping parameter

Description Round Mapping Systematic Mapping Example/ Comments

Estimated/ Calculated

Example/ Comments


2-1 RQD Rock Quality Designation

The % of competent drill-core sticks > 100 mm in length in a selected domain. (In tunnel mapping imaginary cores or scan-lines). See details Appendix 1.

The RQD value for the round.


The RQD value for the mapped section.


2-2 Jn Joint set number

The rating for the number of joint sets (9 for 3 sets, 4 for 2 sets etc.) in the same domain. See details Appendix 1.

The Jn value in the round.

Estimated The Jn value for the mapped section.


2-3 Jw Joint water reduction factor

The rating for the water inflow and pressure effects, which may cause outwash of discontinuity infillings. See details Appendix 1.

The Jw value in the round.

Estimated The Jw value for the mapped section.

Estimated

2-4 SRF Stress Reduction Factor

The rating for faulting, for strength/stress ratios in hard massive rocks, for squeezing or for swelling in soft rock. See details Appendix 1.

The SRF value in the round.

Estimated The SRF value for the mapped section.

Estimated

2-5 Jr Joint roughness number

The rating for the roughness of all joint sets or filled discontinuities. See details Appendix 1.

The Jr value in the round

Estimated

The Jr values (for fractures with a length over 1 m) in the mapped section; 1st quarter, average, 3rd quarter and median.

Calculated, see Appendix 4.

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2-6 Ja Joint alteration number

The rating for the degree of alteration or clay filling of all joint sets or filled discontinuities. See details Appendix 1.

The Ja value in the round

Estimated

The Ja values (for fractures with a length over 1 m) in the mapped section; 1st quarter, average, 3rd quarter and median.


2-7 Q'-value Numerical value for Q' value. See details Section 2.6 (0.001–1333).

The Q' values in the round. Specific value for the left wall, the right wall and the roof.

Calculated The median Q' value for the mapped section.


2-8 Q-value Numerical value for Q value. See details Section 2.6 (0.001–1333).

The Q values in the round. Specific value for the left wall, the right wall and the roof.

Calculated The median Q value for the mapped section.


2-9 Q'-quality

Q' quality classification (Exceptionally Good, Extremely Good, Very Good, Good, Fair, Poor, Extremely Poor, Exceptionally Poor).

The Q' classification values in the round. Specific value for the left wall, the right wall and the roof.

Calculated The median Q' classification value for the mapped section.


2-10 Q-quality

Q quality classification (Exceptionally Good, Extremely Good, Very Good, Good, Fair, Poor, Extremely Poor, Exceptionally Poor).

The Q classification values in the round. Specific value for the left wall, the right wall and the roof.

Calculated

The median Q classification value for the mapped section.


2-11 Rock Type

The main rock type for the left wall, the right wall and the roof. For explanation to abbreviations see Section 3.1.

VGN, DGN, SGN, PGR, MGN, QGN, TGG, KFP, DB and MFGN.

Estimated

2-12 Grain Size

The grain size for the rock type in the left wall, the right wall and the roof.

< 1mm, 1-5 mm, 5-50 mm and > 50 mm.

Estimated

2-13 Fracture set specific data: Orientation (dir).

Dip direction of the plane.

Specific values for the various sets (set 1, set 2, set 3 and set 4).

Calculated/ Estimated, see Appendix 4.

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2-14 Fracture set specific data: Orientation (dip).

Dip angle of the plane.


Calculated/ Estimated, see Appendix 4.

2-15 Fracture set specific data: Jr

The median Jr values within the fracture sets.



2-16 Fracture set specific data: Ja

The median Ja values within the fracture sets.



2-17 Fracture set specific data: Friction angle

The median value for the friction angle, see details in Section 3.2.



2-18 Fracture set specific data: Waviness angle

The median value for the waviness angle, see details in Section 3.2.



2-19 Fracture set specific data: Length

Median fracture trace length within the various fracture sets.



2-20 Fracture set specific data: Count

Number of fractures occurring within a specific set.


Estimated/ Calculated, see Appendix 4.

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Table 2-5. Description of the various mapping parameters used in the ONKALO access tunnel. A grey box indicates that that mapping parameter is used in only one of the two mapping stages. The dashed sections indicate that no new values/limits are proposed for that mapping parameter.

Mapping parameter

Description

Round Mapping Systematic Mapping

Element CurrentValues/ Limit

Proposed Values/ Limits

Element

CurrentValues/

Limit

Proposed

Values/ Limits

3-1 Structural element

Fracture (JO), Tunnel Crosscutting Fracture (TCF), Foliation (FOL), Fold axis (FAX), Axial plane (AXP), and Lineation (LIN).

JO, TCF, FOL

JO, TCF, FOL are elements currently used during round mapping.

JO, TCF, FOL, FAX, AXP, LIN

All elements are currently used during systematic mapping.

Hole Crosscutting Fracture HCF

3-2 Orientation (Dip)

Orientation for structural element, dip angle of the plane or plunge of a linear structure.

JO, TCF, FOL

0–90°


0–90°

3-3 Orientation (Dir)

Orientation for structural element, dip direction of the plane or trend of a linear structure.

JO, TCF, FOL

0–360°


0–360°

3-4 Number of fractures

Number of fractures “clustered” together. For details see Section 3.3.1.

JO, TCF 1-10

3-5 Fracture spacing (m)

Spacing between the “clustered” fractures.

JO, TCF 0-1

3-6 Fracture length (m)

Visible trace length of the fracture.

JO, TCF >1 m JO, TCF ≥ 0.25 m

3-7 Jr (Number)

Derived from Q classification, see Appendix 1.

JO, TCF 0.5-4 JO, TCF 0.5-4

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3-8 Jr (Profile)

Derived from Q classification, see Appendix 1. (PSL=Planar Slickenside, PSM=Planar Smooth, PRO=Planar Rough, USL= Undulating Slickenside, USM= Undulating Smooth, URO= Undulating Rough, SSL=Stepped Slickenside, SSM= Stepped Smooth, SRO=Stepped Rough).

JO, TCF

PSL,PSM, PRO,USL USM,URO,SSL,SSM, SRO

JO, TCF

PSL,PSM, PRO,USL USM,URO,

SSL,SSM, SRO

3-9 Undulation (cm/m)

Undulation (in cm) of a fracture for a 1 m distance.

JO, TCF 0-50

3-10 Ja (number)

Derived from Q classification, see Appendix 1

JO, TCF 0.75-20 JO, TCF 0.75-20

3-11 Fracture filling mineralogy + thickness (mm)

Specifying average thickness for each filling mineral. Consists of a list of 12 most common fracture fillings and cell for accessory minerals (ACC MIN). Appendix 3 and 6.

JO, TCF

See list in Appendix 3 and 6.

3-12 Total thickness

Average thickness for fracture filling

JO, TCF 0.1-∞

3-13 Aperture (mm)

Aperture of a fracture (in mm). JO, TCF 0-∞

3-14 Fracture termination #1 (End1)

Fracture termination.

JO, TCF

P=End, Y=Combine J=Continue

3-15 Fracture termination #1 (to)

If above is Y, then the ID (Joint ID) of the fracture it combines with.

JO, TCF Joint ID number.

3-16 Fracture termination #2 (End2)

Fracture termination.

JO, TCF

P=End, Y=Combine J=Continue

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3-17 Fracture termination #2 (to)

If above is Y, then the ID (Joint ID) of the fracture it combines with.

JO, TCF Joint ID number.

3-18 Rock type code

Rock type that the structural element mostly occurs in. See rock type codes in section 3.1.

JO, TCF, FOL

VGN, DGN, SGN, PGR, MGN,QGN,TGG, KFP, DB, MFGN


VGN,DGN,SGN,PGR,

MGN,QGN,TGG,KFP,

DB,MFGN

3-19 Foliation (type)

Type of foliation, see details in Section 3.2. FOL

BAN,GNE,SCH,IRR.MAS

3-20 Foliation (intensity)

Intensity of foliation, see details in Section 3.2.

FOL 0-3

3-21 Water leakage (fractures)

Current water leakage from a fracture, see details in Section 3.7. JO, TCF

Dry, Damp,Wet, Dripping, Flowing

JO, TCF

Dry, Damp, Wet,

Dripping,

Flowing

3-22 F_vector (F_Dip)

Plunge of a slip direction for a slickensided fracture (referred to as a PSL, USL or SSL in Jr classification).

JO, TCF 0–90°

3-23 F_vector (F_Dir)

Trend of a slip direction for a slickensided fracture (referred to as a PSL, USL or SSL in Jr classification).

JO, TCF 0–360°

3-24 Sense of movement

Sense of movement (on a slickensided fracture) as seen from above.

JO, TCF

Sense of movement will be decided with the procedure proposed by Milnes et. al. (2007);

unknown,

hanging-wall up (HWU),

hanging-wall down (HWD),

dextral (DEX), sinistral (SIN)

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3-25 Uncertainty

Uncertainty of the sense of movement, based on the geologists’ judgment.

JO, TCF

V=certain E=uncertain EE=very uncertain

3-26 Displacement (cm)

Observed displacement (in cm) of a fracture.

JO, TCF 0-∞

3-27 Ri-Class

The Ri Class for the TCF (for further details see Table 3.3.2-1).

TCF RiI-RiV

3-28 Deformation phase

Value from 1-5, denoting the five deformation phases recognised from Olkiluoto. Mostly used for FAX and AXP.

FAX, AXP 1-5

3-29 Remarks

Additional information valuable for the observation.

JO, TCF, FOL

Extra info and location of the measured fracture denoted by K (roof), O (right wall) and V (left wall)


Extra info.

3-30 Zone Intersection

Official ID of the deformation zone intersection that the fracture occurs in.

JO, TCF

For example, ONK-VT1-BFI-4377

3-31 TCF number

Each measured TCF or M fracture gets own designation. See Section 2.1.3

TCF, JO P402, M152

3-32 Sample Sample from a fracture (filling).

JO, TCF

“Yes” if a sample is acquired from a fracture.

3-33 Photo Photo from mapped area

JO, TCF, FOL, FAX, AXP, LIN, rock type

"Yes" if a photo is acquired from a mapped area

3-34 Schmidt Test (R-value) #1-10

R value from the Schmidt hammer, measurements carried out on a planar fracture/rock surface.

JO, TCF, Rock type

R-value from 10–100.

It is pro-posed to acquire Schmidt hammer values in the Supplementary phase

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3-35 Set No. (In data processing sheet, Appendix 4)

Interpretation of which set (in the investigated section) the fracture belongs to.

JO, TCF 1-4

3-36 Friction angle (degree)(In data processing sheet, Appendix 4)

Calculated value for the friction angle, see details in Section 3.5.

JO, TCF 1.43–79.38

3-37 Waviness angle (degree)(In data processing sheet, Appendix 4)

Calculated value for the waviness angle, see details in Section 3.5. JO, TCF

0-45.00

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Table 2-6. Description of the geological data acquisition spreadsheet headings used during zone intersection mapping in the ONKALO access tunnel.

Mapping parameter

Description Supplementary Studies/ Zone Intersection

Example

4-1 Site

Denotes where the mapping is done.

ONKALO

VLJ repository

4-2 Tunnel ID Describes where in the tunnel the mapping is performed.

VT1 = ONKALO access tunnel

KPE1 = ONKALO shaft access

4-3 Intersection type

Describes the type of the intersection Classification of deformation zones (Milnes et al. 2007).

BJI, BFI, SFI, DSI, HGI

4-4 ZONE start (tunnel PL from)

Chainage where the zone starts. Measured at 1 m above tunnel floor

56.3

4-5 Zone Intersection ID

Complete name for the zone ONK-TDT-4399-30-BFI-56.3

4-6 Tunnel profile Numerical value for each type of tunnel profile.

523 = demonstration tunnel

501 = access tunnel

4-7 Tunnel dip Gradient of the tunnel pre determined by the profile used in the excavated section.

1:-10.00 = straight part of the access tunnel

1:-11.63 = curved part of the access tunnel

4-8 Tunnel direction

Downward direction of the tunnel where the mapping is conducted.

0–360°

4-9 Mapping date Date and time when mapping is performed.

25.1.2012 = 25 January 2012

4-10 Geologist Official abbreviation (acquired from TVO permit database) of the geologist and/or assistant who completed the mapping.

NJK

4-11 Zone position

Zones position in tunnel Determined from four different planes.

Left wall

Right wall

Roof

Middle +1m

4-12 Chainage (m)

Chainages (from-to) where zone cuts 1 m line above tunnel floor in four different positions (See 4-11 cell above).

56.30-63.00

4-13 Orientation (degrees)

Orientation for structural element, dip angle of the plane or plunge of a linear structure and orientation for structural element, dip direction of the plane or trend of a linear structure in four different positions (See 4-11).

87/272

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4-14 Water leakage

The rating for the water inflow and pressure effects, which may cause outwash of discontinuity infillings.

Dry, Damp, Wet, Dripping, Flowing

4-15 Sketch Mention if sketch is drawn yes, no

4-16 Sample Mention if sample is taken yes, no

4-17 Connection to previously known intersections/deformation zones

Name of the formerly mapped zone which in high probability is a part of the same larger deformation zone.

ONK-BFI-4377

4-18 Fracture code(s) (within the core zone/within the damage zone)

Fracture codes of those fractures, which are within the core zone/damage zone. Codes are given in systematic mapping phase.

55_1, 60_58

4-19 Zone 1. Characteristics of the "Pre core, damage zone"

Contains description, width (m), Ri Class and Q Classification of the pre core, damage zone

For details, see Appendix 5

4-20 Zone 2. Characteristics of the "Core zone"

Contains description, width (m), Ri Class and Q Classification of the core zone


4-21 Zone 3. Characteristics of the "Post core, damage zone"

Contains description, width (m), Ri Class and Q Classification of the post core, damage zone


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3 EVALUATION AND DEVELOPMENT OF MAPPING PROCEDURE

The current mapping procedure is described in Chapter 2. Many changes have been made since Engström & Kemppainen (2008) was published and the development of the mapping procedure is still continuing. In this Chapter, the possible changes to and development of the mapping procedure for the ONKALO tunnel (and associated openings) are listed and discussed.

All input and ideas for improving the geological and geotechnical mapping procedures are welcome.

3.1 Round mapping

No requirements for the development of round mapping practises have been identified up to date.

3.2 Systematic Mapping

It is suggested that two new columns should be added in the systematic mapping spreadsheet to provide more accurate information about each mapped section - one for the leucosome content of the section and the other for the type of the mineralogical alteration of the section.

3.2.1 Leucosome content

Currently, the leucosome content in gneisses is sporadically mentioned in the Notes section of the systematic mapping spreadsheet. It is not systematically estimated for each of the mapped sections. For this reason it is suggested that a separate column for the gneiss leucosome content in percent (%) is added in the spreadsheet; and this would provide more accurate information about the different gneiss types in the ONKALO access tunnel.

3.2.2 Type of the mineralogical alteration

It is suggested that two columns be added in the systematic mapping spreadsheet for more detailed description of the mineralogical alteration. One column would be needed to indicate the type of the alteration and one to describe the mineral(s) present. The categories for the alteration type would be pervasive alteration, fracture controlled alteration and none, if no mineralogical alteration is observed in the mapped section. The alteration mineral column would indicate which mineral is replacing the original mineral particles (e.g. graphite, calcite, kaolinite).

3.3 Supplementary studies

3.3.1 Deformation zone intersections

3.3.1.1 Water leakage

During the detailed mapping of the deformation zone intersections, the location of possible water leakages should be recorded, i.e. whether the leakage is located within the pre-core, core, or post-core zone. In addition, a more detailed description of the

36

leakage(s) should be provided, and if feasible, the locations of the main leakages should be measured with the tachymeter. Possible changes to the mapping sheet should be evaluated.

37

ACKNOWLEDGEMENTS

The author would like to thank Paula Kosunen (Posiva Oy) and Tim McEwen (McEwen consulting) for reviewing the report and for valuable and constructive comments. The author would also like to give a special thanks to Emmi Eroma for starting this project.

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REFERENCES:

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

Barton, N. Lien & R. Lunde, J. 1974. Engineering classification of rock masses for the design of tunnel support. Rock Mechanics, Vol 6, No 4, p. 189–236.

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. Eurajoki, Finland: Posiva Oy. Working report 2008-77.

Gardemeister, R., Johansson, S., Korhonen, P., Patrikainen, P., Tuisku, T. & Vähäsarja, P. 1976. Application of the Finnish engineering geological classification (in Finnish). Espoo, Finland: Technical Research Centre of Finland, Geotechnical laboratory, Research note 25, 39 p.

Grimstad, E. & Barton, N. 1993. Updating of the Q-system for NMT. Proc. of the International Symposium on Sprayed Concrete. Fagernes, Norway. Kompen, E. Opsahl, Berg. Norwegian Concrete Association, p. 46–66.

Kärki, A. & Paulamäki, S. 2006. Petrology of Olkiluoto. Eurajoki, Finland: Posiva Oy. Posiva 2006-02. 77 p.

Korhonen, K-H., Gardemaister, R., Jääskeläinen, H., Niini, H. & Vähäsarja, P. 1974. Rakennusgeologinen kallioluokitus (The Engineering geological bedrock classification in Finnish). Technical Research Centre of Finland, Geotechnical laboratory, Research note 12, 78 p.

Lehtinen, A. & Hirvonen, H. 2007. Water sampling from the leaking structures and fractures after grouting in ONKALO 2005-2006. Eurajoki, Finland: Posiva Oy. Posiva 2006-28.

Mattila, J. 2006. A system of Nomenclature for Rocks in Olkiluoto. Eurajoki, Finland: Posiva Oy. Working report 2006-32.

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. 510 p.

Milnes, A. G., Hudson, J. A., Wikström, L. & Aaltonen, I., 2006. Foliation: Geological Background, Rock Mechanics Significance, and Preliminary Investigations at Olkiluoto. Working Report 2006-03. Posiva Oy, Eurajoki. 79 p.

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Milnes, A. G., Aaltonen, I., Ahokas, T., Front, K., Gehör, S., Kemppainen, K., Kärki, A., Mattila, J., Paananen, M., Paulamäki, S. & Wikström, L. 2007. Geological Data Acquisition for Site Characterisation at Olkiluoto: a Framework for the Phase of Underground Investigations. Working report 2007-32. Posiva Oy, Eurajoki. 133 p.

Munier, R. 2006. Using observations in deposition tunnels to avoid intersections with critical fractures in deposition holes. SKB R-06-54, Svensk Kärnbränslehantering AB.

Nordbäck, N. 2013. Outcome of the Geological Mapping of the ONKALO Underground Research Facility Chainage 3116-4986.

Paulamäki, S., Paananen, M., Front, K., Gehör, S., Kärki, A., Aaltonen, I., Ahokas, T., Kemppainen, K., Mattila, J. & Wikström, L. 2006. Geological model of the Olkiluoto site, Version 0. Working report 2006-37. Posiva Oy, Eurajoki. 355 p.

Posiva 2003. ONKALO Underground Characterisation and Research Programme (UCRP). Eurajoki, Finland: Posiva Oy. Posiva 2003-03.

Posiva Oy, 2012. Olkiluoto Site Description 2011 (ISBN 978-951-652-179-7). Posiva Report 2011-02. Posiva Oy, Eurajoki.

Scholz, C.H. 2002. The Mechanics of Earthquakes and Faulting. 2nd Edition. Cambridge University Press, Cambridge, United Kingdom.

Sibson, R.H., 1977. Fault rocks and fault mechanisms. Journal of the Geological Society (London), 133, p. 191-214.

Wimmenauer, W. & Bryhni, I. 2007. Migmatites and related rocks. In Fettes, D. and Desmons, J. (eds.) Metamorphic Rocks – A Classification and Glossary of Terms. Cambridge University Press, Cambridge, United Kingdom. p. 43-45.

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4 APPENDICES:

Appendix 1: Description of the various Q parameters: RQD, Jn, Jr, Ja, Jw and SRF.

Appendix 2: Spreadsheet used in the round mapping of the ONKALO access tunnel.

Appendix 3: Spreadsheet used in the systematic geological mapping of the ONKALO access tunnel.

Appendix 4: Spreadsheet used in the processing of the systematic geological mapping data acquired in the ONKALO access tunnel.

Appendix 5: Spreadsheet used for mapping deformation zone intersections in the ONKALO access tunnel.

Appendix 6: Fracture filling mineral abbreviations used in systematic geological mapping of the ONKALO access tunnel.

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Appendix 1. Description of RQD (1), Jn (2), Jr (3), Ja (4), Jw (5) and SRF (6) (Grimstad & Barton 1993).

45

Appendix 2. Spreadsheet used in the round mapping of the ONKALO access tunnel.

47

Appendix 3. Spreadsheet used in the systematic mapping of the ONKALO access tunnel.

49

Appendix 4. Spreadsheet used in the processing of the systematic mapping data acquired in the ONKALO access tunnel.

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Appendix 5. Spreadsheet used for the mapping of deformation zone intersections in the ONKALO access tunnel.

ZONE INTERSECTIONDATA IMPORT

Site Tunnel IDONKALO TDT-4399-30

523 1:50 320 12.9.2011 PJUH

From To Dip Dip dir.

35.80 36.00 50 177

31.70 33.50 57 151

38.00 40.00 50 162

33.00 34.00 50 175

Within the core

zone Within the damage zone

Dry No No30_5,30_7

,30_6.

30_2,30_4,30_3,30_14,30_13,30_9,30

_10,30_30,30_31,30_23,30_27,30_26,

30_28.

Zone1 Hanging wall

Width (m)1

Ri-Class

RiII

RQD Jn Jr Ja Jw SRF Q Q-quality100 0.5 3 4 1 5 30.000 Good

Zone2 HWD

Width (m)0.1

Ri-Class

RiIV‐Rk4

RQD Jn Jr Ja Jw SRF Q Q-quality20 2 0.5 6 1 5 0.167 Very Poor

Zone3 Footwall

Width (m)1

Ri-Class

RiII

RQD Jn Jr Ja Jw SRF Q Q-quality80 4 0.5 4 1 5 0.500 Very Poor

Connection to previously known intersections / deformation

zones

Q-CLASSIFICATION

Orientation (degrees)Tunnel part

Q-CLASSIFICATION

left wall

right wall

roof

middle +1 m

Water leakage

Sketch Sample

Intersection type ZONE start (tunnel PLfrom)BFI 31.7

Tunnel dip

Tunnel direction

Mapping date

Geologist

Characteristics of the "Post core zone, damage zone"Description

The post‐core zone consists of increased fracturing occuring after the core zone. The post‐

core zone also contains large amounts of suphides and graphite in the rock matrix and on

the fracture surfaces. These minerals occur in the rock matrix itself and t

The pre‐core zone is poorly developed and the core begins straight from intact rock in both

walls. The only exception is the floor where fault‐connected fractures form a pre‐core

influence zone that is 1‐1.5 m wide. The wallrock before, within and after t

Q-CLASSIFICATION

Characteristics of the "Core zone"Description

Characteristics of the "Pre core zone, damage zone"Description

Fracture Code(s)

ONK‐TDT‐4399‐44‐BFI‐22.3, ONK‐TT‐4399‐

BFI‐62.6

The core‐zone consists of a 2‐20 cm wide, intensively fractured graphite and sulphide‐rich

core. In the floor a ~5 cm wide calcite‐cemented breccia has been developed in some parts

of the core. The profile of the main fault plane varies from planar to sli

Zone Intersection IDTunnel profile

ONK-TDT-4399-30-BFI-31.7Zone position Chainage (m)

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Appendix 6. Official fracture filling mineral abbreviations used in the systematic geological mapping of the ONKALO access tunnel. All of these cannot be recognised during the mapping in the ONKALO.

Abbreviation Mineral Abbreviation Mineral

AN = analcime KS = kaolinite + other clay minerals

BT = biotite KV = quartz

CC = calcite LM = laumontite

CU = chalcopyrite MH = molybdenite

DO = dolomite MK = pyrrhotite

EP = epidote MO = montmorillonite

FG = phlogopite MP = black pigment

GR = graphite MS = feldspar

GS = gismondite MU = muscovite

HB = hydrobiotite NA = nakrite

HE = hematite PA = palygorsgite

IL = illite PB = galena

IM = grouting material SK = pyrite

IS = illite + other clay minerals

SM = smectite

KA = kaolinite SR = sericite

KI = kaolinite + illite SV = clay mineral

KL = chlorite VM = vermiculite

KM = K-feldspar ZN = sphalerite

LIST OF REPORTS

POSIVA-REPORTS 2015

_____________________________________________________________________

POSIVA 2015-01 Geological and Geotechnical Mapping Procedures in use in the ONKALO Juhani Norokallio, Posiva Oy ISBN 978-951-652-243-5

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