packfill - development of in situ compactionand the effect of the compactor has been studied. based...

P O S I V A O Y

FI -27160 OLKILUOTO, F INLAND

Tel +358-2-8372 31

Fax +358-2-8372 3709

Leena Kork ia l a -Tant tu

Pau la Keto

P i r j o Kuu la -Vä i sänen

Nuut t i Vuor im ies

D ie tmar Adam

September 2007

Work ing Repor t 2007 -75

Packfill - Development of in Situ CompactionTest Report for Field Tests November 2005

September 2007

Working Reports contain information on work in progress

or pending completion.

The conclusions and viewpoints presented in the report

are those of author(s) and do not necessarily

coincide with those of Posiva.

L e e n a K o r k i a l a - T a n t t u

V T T

Pau la Keto

Saan io & R iekko la Oy

P i r jo Kuu la -Vä isänen , Nuut t i Vuor im ies

Tampere Un ive rs i t y o f Techno logy

Dietmar Adam

Techn ica l Un ive rs i t y o f V i enna

Work ing Report 2007 -75

Packfill - Development of in Situ CompactionTest Report for Field Tests November 2005

ABSTRACT

Methods for backfilling and sealing of disposal tunnels in an underground repository for spent nuclear fuel have been studied in cooperation between Finland (Posiva Oy) and Sweden (Svensk Kärnbränslehantering AB, SKB) in Baclo programme. The considered methods in programme are installation of pre-fabricated blocks and compaction at site and the considered materials are different type of clays with swelling ability and mixture of ballast and bentonite clay. The Baclo project has been divided into work packages. Work package 2 (WP2) concentrates on the in-situ compaction of mixture of crushed rock (70%) and bentonite (30%). In the step 2 in WP2 the compaction methods and the effect of the compactor has been studied. Based on the literature review the Packfill test construction study was launched. The objectives of the packfill test construction study were to find out the acceptability of in-situ backfilling, to acquire data of the material behaviour during compaction, to find solutions for in-situ backfilling and to compare different compactors. Packfill study includes two parts. This study concentrates on the material parameters, comparison of compactors and further development of the compaction method while the other study will concentrate on the modelling. The studies have separate reports.

Certain strict criteria have been set for the backfill in order to maintain the function of engineered barriers in the repository for a very long time period. For example, the hydraulic conductivity (k) of the backfill material shall be lower than 1·10-10 m/s. In practice this means that the mixture needs to be compacted to very high dry density (90-95% from maximum Proctor dry density). Several studies have been made to find optimum composition for the in-situ backfill material. Based on the studies, the optimum water content of the mixture of ballast (70%) and bentonite (30%) is between 11...12.5% and the corresponding dry density is about 1870 kg/m3. The tested material can be described as a low plastic semi-cohesive material, which is quite sensitive to the exceeding of the optimum water content.

The test construction was done in two phases. The first one was on the 10.11.-11.11.2006 and the other one on the 28.11.2006. The test construction was made in Ekokem’s facilities in Riihimäki.

Two test structures were constructed in order to produce data for modelling the effect of different compaction equipment parameters. One test structure (size about 2.5 x 3.5 m2) was constructed in 150...250 mm thick horizontal layers and it was compacted with a light vibratory plate. The other test structure was constructed into layers with inclination of about 30�. The inclined structure was first compacted with the modified roof compactor and later with a multipurpose compactor and a heavy roller for comparison. The density of the compacted surface was followed with Troxler and sand volumeter tests. The deformation properties of the surface were measured with LDWT and Loadman. Besides Troxler measurements, the water content of the material was

followed with different drying methods. The mixture was in about the same water content in both tests.

The test results showed that with these methods and equipments the high density requirements of repository tunnel could not be achieved. However, relatively good compaction results were achieved though the compaction methods were not optimized for this purpose. The highest average dry densities were achieved with the heavy roller (in average 1744 kg/m3). Horizontal compaction with vibratory plate proved to be nearly as efficient method (in average 1655 kg/m3) as the heavy roller. The target degree of compaction (90%) was achieved only with the heavy roller. The needed modelling data was achieved from the test.

Even though the highest density requirements of the repository tunnel were not achieved, the test gave many positive results and proved that a relatively compact tunnel backfilling can be achieved with these methods. The used methods could be used for example in the compaction of backfilling of other deep excavations.

The compaction work is sensitive to the excess of water content and to the thickness of layers. The inclination had a tendency to become more gentile (from 30� to about 24�) during the compaction. The roller compactors could not be used for compaction of inclined layers without additional arrangements.

Packfill - paikallaantiivistämisen kehittäminen. Testiraportti kenttäkokeista marraskuussa 2005. TIIVISTELMÄ

Posiva Oy ja Svensk Kärnbränslehantering AB ovat yhdessä koordinoineet ydinjätteen loppusijoitustunnelin täyttö- ja sulkemisohjelmaa (Baclo). Ohjelman II vaihe jaettiin työtehtäviin, joista tehtävässä 2 (WP2) on tutkittu tunnelin in-situ täyttö konseptia, jossa tunneli täytetään kalliomurskeen ja bentoniitin sekoituksella (70 % / 30 %) ja tiiviste-tään täytön edetessä. Tehtävä on jaettu edelleen kahteen osatehtävään, joista vaiheessa 1 (step 1) on tutkittu materiaaliparametrien vaikutusta tiivistettävyyteen. Tämän tutki-muksen edustamassa vaiheessa 2 (step 2) on tutkittu tiivistyskaluston vaikutusta tiiviy-teen. Vaiheen 2 tutkimukset alkoivat Dietmar Adamin laatimalla kirjallisuusselvityk-sellä. Selvitys suositti numeeristen mallinnusten suorittamista tiivistämistuloksen optimoinniksi. Selvityksen perusteella käynnistettiin Packfill – koerakennustutkimus, jonka tavoitteena oli selvittää, kannattaako in-situ konseptin suunnittelua jatkaa, hank-kia tietoja materiaalin käyttäytymisestä tiivistämisen aikana, löytää ratkaisuja tunnelin täyttömenetelmiin sekä vertailla erilaisia tiivistyskalustoja toisiinsa. Packfill –tutkimus sisältää kaksi osatutkimusta, joista tämän koerakentamisosan tavoitteena oli etsiä materiaaliparametreja mallintamista varten, vertailla eri tiivistyskalustoja toisiinsa ja kehittää tiivistysmenetelmää edelleen. Toisessa osatutkimuksessa esitetään tiivistämisen mallinnuslaskelmat. Osatutkimukset raportoidaan erikseen.

Lopputäytölle on asetettu tiukat pitkäaikaiset toiminnalliset vaatimukset. Esimerkiksi täytteen vedenjohtavuuden tulee olla pienempi kuin 1·10-10 m/s. Jotta näin vesitiiviisiin täyttöihin päästään, tulee bentoniitti – murske seoksen kuivatiiviyden olla 90…95 % maksimi Proctor kuivatiheydestä. Bentoniitti – murske sekoitusten optimiratkaisua on etsitty useassa eri tutkimuksessa. Tutkimusten mukaan bentoniitti (30 %) ja murske (70 %) sekoituksen optimivesipitoisuus on 11…12,5 % and vastaava kuivatiheys on 1870 kg/m3. Sekoitus on luonteeltaan vähän plastista puoli-koheesiivista materiaalia, joka on suhteellisen herkkä optimivesipitoisuuden ylityksille.

Koerakentaminen tehtiin kahdessa jaksossa. Ensimmäinen jakso oli 10.11.-11.11.2005 ja toinen oli 28.11.2005. Koerakentaminen tehtiin Ekokem Oy:n hallissa Riihimäellä. Testattava murske - bentoniittiseos sekoitettiin paikan päällä 8.11.-10.11.2005. Mate-riaali siirrettiin halliin, jossa siitä rakennettiin kaksi koepengertä. Pienempi penger (koko noin 2,5 x 2,5 m2) rakennettiin neljästä vaakasuuntaisesta noin 150...250 mm paksuisesta kerroksesta ja jokainen kerros tiivistettiin erikseen. Laajempi koerakenne sijoitettiin hallin reunaluiskaa (1:1,5) vasten ja siinä noin 150…250 mm kerrokset rakennettiin luiskatuissa kerroksissa. Koerakentamisen aikana testattiin neljää eri tiivistyskalustoa. Nämä neljä kalustoa olivat:

tärylevy 1: Halltekin tärylevy kiinnitettynä Gradallin teleskooppivartiseen jyrään

tärylevy 2: Dynapac LH700 monitoimijyrä (sorkkajyrä) BOMAG BMP851 raskas sileävalssinen täryjyrä BOMAG BW211-D3.

Vaakasuuntainen kerrosrakenne tiivistettiin Dynapac LH700 ohjattavalla tärylevyllä. Luiskatussa rakenteessa testattiin kolmea muuta jyrää.

Rakentamisen ja tiivistämisen aikana seurattiin materiaalin vesipitoisuutta, tiiviysastetta (Troxler ja vesivolymetri) ja kantavuutta (Loadman ja LDWT). Materiaalin ominai-suuksia sekoituksen aikana ja sen jälkeen seurattiin lisäksi erilaisilla kuivatusmene-telmillä. Materiaalin vesipitoisuus kummankin työjakson aikana oli lähes sama, vaikka materiaalia oli välissä säilytetty yli kaksi viikkoa hallissa. Kokeista saatiin mitatuksi mallinnuksessa tarvittavat parametrit.

Koetulosten mukaan loppusijoitustunnelin tavoitetiheyttä ei täysin saavutettu millään käytetyistä testijyristä tai tiivistysmenetelmistä. Korkeimpaan keskimääräiseen kuiva-tiheyteen (1744 kg/m3), joka vastaa 90 % tiiviysastetta päästiin raskaalla täryjyrällä. Vaakakerrostiivistyksellä kevyemmällä tärylevyllä saavutettiin lähes yhtä hyvä tulos, eli keskimäärin 1655 kg/m3 kuivatiheys. Saavutetut tiiviystasot käytetyilläkin menetelmillä ovat lupaavia, vaikka menetelmiä ei oltu erityisesti optimoitu käytetyllä materiaalille. Käytettyjä menetelmiä voitaneen sellaisenaan käyttää alemman tiiviysvaatimuksen edellyttävien muiden kalliotilojen täyttöjen tiivistämiseen.

Tiivistystulos riippuu tiivistettävien kerrosten paksuudesta ja se on herkkä liian suurille vesipitoisuuksille. Luiskatuissa testirakenteissa luiskan kaltevuus loiveni kokeen aikana kaltevuuskulmasta 30º noin 24º kulmaan. Monitoimijyrää voitiin käyttää luiskatun rakenteen tiivistämiseen vain lisäjärjestelyin.

FOREWORD

Posiva Oy (Posiva) and Swedish Nuclear Waste Management Company (SKB) coordinates the 4 phase programme of “Backfilling and Closure of the deep repository” (Baclo). During the second phase (2004-2005) one aim was to judge different backfilling materials and methods and select few alternatives for continuation. The work was divided into the 7 work packages. The second work package (WP2) was managed by Posiva. The scope of the work was to analyse if compaction procedure in the field can be improved so that requirements set for the backfilling can be fulfilled. The work package WP 2 “Compaction properties of backfill materials concerning in situ compaction” included following steps:

Step 1 Investigating the influence of material parameters on compactibility Step 2 Investigating the influence of compaction equipment properties on

compactibility. The main outcome from a literature study made in Step 2 was the need to increase knowledge regarding in situ compaction for semi-cohesive material. The following optimization procedure of compaction techniques was proposed in this study by Dietmar Adam /2005/. The compaction could be optimized by numerical simulations, whereby the following investigations were recommended:

�� Simulation of different compactors with special focus on the operating conditions. �� Determination of stress distribution in the soil and from that derivation of the

compaction depth. �� Optimization of the drum shape. �� Effect of the inclination of surface to be compacted (working platform).

For the determination of the material stiffness parameters used in the numerical simulations small test fields were recommended to be carried out.

This work has been implemented in a separate project running parallel with the Baclo programme. This Posiva-SKB joint project was named Packfill- in situ development for deep repository. The scope of this work is:

�� to see if there is potential to continue with in situ backfilling concept, �� to increase the knowledge about material behavior during compaction, �� to find solutions for backfilling and sealing the other underground repository

facilities (than the disposal tunnels) �� This work consists of field testing, which is described in this memorandum and

modeling part, which will be published as a separate memorandum.

Four tested compactors were:

�� Vibratory plate 1: Halltek's roof compactor with a Gradall carrier �� Vibratory plate 2: Dynapac LH700 �� Multipurpose compactor BOMAG BMP851 �� Vibratory roller BOMAG BW211-D3

The test construction was carried out by Ekokem - Palvelut Oy. Ekokem - Palvelut Oy's coordinator of test was Antti Kaartokallio. Jan Österbacka, Jukka Palo-oja and Päivi Ojamäki collaborated on the test and made field measurements. Ekokem - Palvelut Oy had two subcontractors: Maanrakennus Matti Pitkä Oy provided the excavator for the construction of embankment and Hyvinkään Tieluiska Oy for the provided carrier Gradall. The multicompactor was rented from Konevuokraamo P. Salminen Oy. Dr. Dietmar Adam from the Technical University of Vienna made the LDWT measurements. The developer of the roof compactor Lennart Hallstedt from Halltek AB was advising the roof compaction work. Johanna Hansen from Posiva Oy, Paula Keto from Saanio & Riekkola Oy and David Gunnarsson from Swedish Nuclear Waste Management company (SKB) were following the test. The grain size distribution and triaxial tests of the mixture were conducted in the Technical University of Tampere by Pirjo Kuula-Väisänen. The test construction and its reporting were coordinated by Leena Korkiala-Tanttu VTT Technical research Centre of Finland. The test report includes test results of Ekokem - Palvelut Oy, VTT and Technical University of Vienna. The description of the test construction bases on the notes of Paula Keto and Lennart Hallstedt. Leena Korkiala-Tanttu has edited the notes, collected the test results and processed them.

Espoo, April 2006

VTT

1

TABLE OF CONTENTS

ABSTRACT

TIIVISTELMÄ

FOREWORD

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

2 TEST SITE AND TESTED MATERIAL.................................................................. 5

3 TESTED EQUIPMENTS ON THE FIRST TEST PERIOD (10.11.-11.11.2005) .... 9

4 TESTED EQUIPMENTS ON THE SECOND TEST PERIOD (28.11.2005) ........ 11

5 MEASUREMENTS AND SAMPLING.................................................................. 13

6 COMPACTION OF THE SLOPED TEST STRUCTURES................................... 15 6.1 Compaction of the sloped test structures on the first test period ............... 15 6.2 Compaction of the sloped test structure on the second test period

(28.11.2005)............................................................................................... 17

7 COMPACTION OF THE HORIZONTAL LAYERS............................................... 21

8 LABORATORY TEST RESULTS ........................................................................ 23

9 DISCUSSION ...................................................................................................... 25

10 CONCLUSIONS .................................................................................................. 31

REFERENCES ............................................................................................................. 33

APPENDICES............................................................................................................... 35

3

1 INTRODUCTION

In situ backfilling has been used as a reference concept of backfilling the deep repository /Gunnarsson et al 2003/. In situ backfilling to inclined layers with mixture of crushed rock and bentonite has been studied in several field and laboratory tests (reference backfill and plug, prototype repository etc.) (see e.g. Gunnarsson et al. 2004). Inclined layers have been selected as the main alternative due to the following facts:

�� the space above deposition hole up to the roof will be backfilled quickly �� inclined layers are not as sensitive for ground water dripping to the tunnel as

horizontal layers �� testing has been showed that the method is feasible and fulfils the requirements

when salinity is max TDS 1g/l. The target of the Packfill project is to develop a backfilling method that fulfils the following requirements:

�� The long-term safety issues are especially related to the location of the deep repository, which may be situated in a bedrock formation in which the salinity of the groundwater in the distant future may be significantly higher than its current value. For this reason a ground water salt content of 3.5% has been used as a design assumption in this study. High salinity can influence negatively to the function of the previously considered backfill materials.

�� The technical feasibility is strongly related to the materials considered but there are also common questions to all concepts considered. These are related for example to hydrostatic pressure, possible need for drainage and potential backfilling capacity reached by the technology in question. There is also a need to develop backfilling concepts for other excavations (caverns, transport tunnels, shafts and ramps) for the production backfilling of the repository. A special issue is the workers' safety in the deep repository during the long operation time. For this reason the requirements indicated in the legislation have to be considered.

The field test construction had two targets:

�� The first objective was to acquire parameters for the modelling of compaction of backfill. The modelling will be done in the University of Vienna by Prof. Dietmar Adam. The results will be reported in a separate working report.

�� The second objective was to test different compaction methods and to develop them further. The tested compactors included a modified roof compactor (tested previously in the Prototype tests at Äspö) in order to see if the equipment can be used also for compacting the main part of the slope. Other tested compactors were vibratory plate, multipurpose compactor and a bigger roller.

4

The field tests were performed in two stages: 10-11.11.2005 and 28.11.2005. During the first stage, two different type of vibratory plate were tested. A roof compactor previously tested at Äspö HRL (Sweden) was modified to see if the modifications would result in satisfied compaction result and to study the compaction procedure. The aim of compacting in horizontal layers with another type of plate compactor was mostly to produce data for modelling. During the second stage, the field tests were carried out with two types of compaction rollers. The main idea was to observe the applicability of these methods in inclined layers.

5

2 TEST SITE AND TESTED MATERIAL

Test site

The test site was located next to Ekokem Oy’s production facility at Riihimäki. The test site was an indoor hall, which floor was asphalt concrete with about 2 metres high, 1:1.5 sloped fringe areas. The floor structure of the hall had a total thickness of over 2 metres. On the subgrade there was about 2 metre thick, very stiff stabilized soil layer with plastic membranes. The stabilized layer was covered with two 60 mm thick (together 120 mm) asphalt concrete layers. Two different test embankments with horizontal and sloped layers were constructed. The map of the test hall is illustrated in Figure 1.

Horizontal test structure

Sloped test structure

Figure 1. The map of the test hall with the locations of the test embankments.

The general requirements of the backfill material are presented in the Posiva's working report. Keto et al. /2005/. The maximum grain size of the backfill material in this test construction was 8 mm, which differs for that in the working report. Otherwise, there were no special requirements on the grain size distribution of the material. Posiva Oy provided the used crushed rock from ONKALO -project in Olkiluoto. The grain size distribution of the rock is presented in Appendix 7. The used bentonite was activated Ca-bentonite from Milos Greece (AC-200). The backfill material included 30 weight-%

6

of bentonite and 70 weight-% of crushed rock. The target water content of the mixture was about 12%, which was the assumed optimum value of mixture according to the tests /Keto et al. 2005/. The target dry density of the compacted backfill material was 1.9 tn/m3. The mixture can be described as semi-cohesive material with low plasticity.

The water content of the mix was determined with three different methods (infrared-, micro & drying oven). The measured mass of the mixture and its water content is presented in Appendix 8. The mixture was very sensitive to water content. If the water content was too high, the material turned into lumpy. Three patches of mixed material were disapproved due to the too high water content. The water content of the approved mixture varied between 11.5-13% while the most of values were between 11.5-12%. The water content of the mixture was also measured from the test structures and from the stack of material (Appendix 6).

Mixture of the backfill material

The mixing plant was a modified concrete mixing plant with silos for bentonite and crushed rock (Figure 2). The bentonite was added to the mix at the same time with the water. The total mixing time was from 2 to 3 minutes. Most of this time went to adding the bentonite to the mixture. The duration of adding the water took only 30 seconds. After the all of the components had been added, the mixing was further continued for 20 seconds. The amount of one batch was approximately 1.5 tons. The mixing plant is normally used to the mixing of materials with lower bentonite content (5-10%). The quality of the mixture was controlled with on-line water content measurements.

7

Figure 2. The mixing plant. The conveyor belt at the right is used for feeding the crushed rock. The bentonite is fed from the blue silos at right. The mixing unit is in the centre of the figure. Photo D. Adam.

All the needed material was mixed on the 9th and 10th of November. Thus in the first test period (10.11-11.11.2005) the mixture was 0...2 days old and in the second period (28.11.2005) 18...19 days old. The mixture was not remixed after its preparation. Since the material was stored over two weeks in the test hall, the water content of the mixture had increased a bit from the average value of 11.5% to 11.8%. No separation was observed visually after the storing period.

9

3 TESTED EQUIPMENTS ON THE FIRST TEST PERIOD (10.11.-11.11.2005)

The vibratory plate of Halltek and its carrier (later roof compactor)

The inclined (or sloped) test construction was compacted with a vibratory plate compactor provided and developed by Halltek AB. The vibratory plate used was a modified version of the roof compactor tested at the Prototype repository at Äspö HRL. This equipment was chosen in order to test the principle of using the same plate for compacting both the roof section and the main part of the inclined layer. The plate had weight of 450 kg (excluding the extension arm), vibrating weight of 293 kg, frequency of 43 Hz, amplitude of 2.6 mm and the centrifugal force of 55 275 N. The plate was modified by changing the shape of the foot of the plate (Appendix 1). The width of the foot was 800 mm. The plate and its carrier are presented in Figure 3.

The vibratory plate was attached to the carrier of Gradall XL3300 excavator with a telescopic boom (Figure 3). The technical data of Gradall XL3300 excavator is presented in appendix 12. The carrier and its driver were provided by Hyvinkään Tieluiska Oy. The boom of the carrier was provided with a quick-disconnect fitting enabling fast change of equipment (e.g. bucket/plate). One change of equipment takes approximately 2 minutes. During the test, the pressure in the return and leakage line was measured to be in maximum 9 bar. This pressure is not permitted to exceed 5 bar in continuous work. In order to reduce the pressure the control valve was bypassed for the return line, and the pressure decreased to 1 bar.

Figure 3. The carrier (Gradall XL3300) and the modified roof compactor (the yellow equipment attached to the boom of the carrier). Photo P. Keto.

10

The vibratory plate for horizontal compaction

The vibratory plate tested for the horizontal layer compaction was Dynapac LH700 (later LH700) with net weight of 765 kg, frequency of 53 Hz and amplitude of 2.5 mm (Figure 4). The width of the plate was 660 mm and the length was 1050 mm. The technical data is in appendix 11.

Figure 4. Vibratory plate used for compacting of the horizontal layers. Photo L. Korkiala-Tanttu

11

4 TESTED EQUIPMENTS ON THE SECOND TEST PERIOD (28.11.2005)

Multi-compactor

The lightweight padfoot compactor tested was a BOMAG multipurpose compactor BMP851 (later BMP851) with weight of approximately 1.5 t. The height of the compactor was 1.2 m and the width of the drum 610 mm (see appendix 9 for dimensions of the compactor). The compaction frequency of the multipurpose compactor was 32 Hz, the amplitude was 2.1 mm and the centrifugal force was 80 kN. More data about compactor can be found from the product information in appendix 9.

Vibratory roller

The other tested compactor used was a BOMAG vibratory roller BW211-D3 (later roller 13 tn), with the weight of approximately 13 t. According to product information in appendix 10, the compaction frequency of BW211-3 is 36 Hz and the amplitude is 0.9-1.8 mm.

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5 MEASUREMENTS AND SAMPLING

The densities of the compacted layers were measured with both Troxler and with sand volumeter tests. In the beginning two different Troxler measurement units were used, but later on only one measurement unit (2) was used. In the first test period total three sand volumeter tests (Figure 5) were done, two from the horizontal test embankment and one from the horizontal cutting of the sloped structure. In the second test period two sand volumeter tests were done from the lower and upper cutting after the test. The volumeter tests were laborious, thus the test holes remained quite small. Thus, it is probable that the volumeter test results underestimate the density. The detailed test results of volumeter tests are presented in Appendix 2. All Troxler measurements are presented in Appendices 4 and 5. Since Troxler is measuring the hydrogen content, and because the bentonite itself includes hydrogen, the on-line measured water contents were too high. That is why the water contents and dry densities had to be corrected. Both original and corrected values are presented in the appendices.

The parameters for the modelling (deflection and stiffness modulus E after different passes) were measured with a Light Drop Weight Tester (LDWT) (Figure 5). For comparison deflections were measured also with a Loadman, which is a light weight portable deflectometer. LDWT (technical data in the appendix 13) and Loadman (technical data in appendix 14) tests were also done from the test cuttings of the sloped structure. The Loadman measurements of the bottom asphalt were made with the diameter 132 mm plate and the other measurements were made with 300 mm plate. The Loadman test results are presented in Appendix 3. The technical data of both measuring units can be found from Appendices and in their web-pages (see References).

The target thickness of the layers varied between 150 mm....250 mm. The thickness was measured with a simple stick before compaction and occasionally also after compaction. The thickness of the layers was used mainly for the guidance of the backfilling.

Samples were taken from the crushed rock in order to study the grain size distribution of the ballast material. The mixture was sampled for determination of the water content and optimum water content (Proctor compaction test). The material was also sampled for further testing (grain size distribution, Proctor test and triaxial testing).

14

Figure 5. The test equipments with vibratory plate used in 10.11.-11.11.2005. Photo D. Adam.

15

6 COMPACTION OF THE SLOPED TEST STRUCTURES

6.1 Compaction of the sloped test structures on the first test period

The mixed material had been carried to the hall in the previous day and it was in a stack between the two test structures. The material for each layer was laid with the help of an excavator. The material was laid against the fringe slope. One laying took approximately 5 minutes. The thickness of the layer was controlled with a measuring stick. The target thickness of the layer was 200...250 mm (after compaction). The principal cross section of the construction is illustrated in Figure 6.

Slope 1:1,5

2,0 m

Cuttings

Additional filling

33º28º

Figure 6. The principal cross section of sloped construction in the first test period.

Four layers were compacted with roof compactor in the first day. The measured inclination of the layers was approximately 28° while the inclination of the underlying slope was approximately 33° (1:1.5). The measured layer thickness before compaction varied between 200-300 mm and it was about 100–200 mm after the compaction. The width of the test structure was approximately 4 m. The height of structure was in the beginning about 2 metres. On the second day the aim was to compact in steeper angle, and higher fillings were tried to do against the supporting wall up to 2.4 metres (additional filling). The compaction was made in overlapping sections from down to up (see Figure 7). The compaction time of one section varied from 1.5 to 3.5 minutes and the compaction time of the total layer from 50 minutes (first layer) to 20 minutes. This was the first time the driver worked with this kind of compactor. After more practice the compaction time will probably decrease. The amount of compaction passes per layer was 4–5. The density of the layers III and IV was measured after 3...4 passes (average dry densities 1484...1528 kg/m

3) and after 2...4 additional passes (average dry densities

1633...1642 kg/m3).

16

On the second day a test cutting was dug for making the LDWT & Troxler tests. The average dry density measured from the cutted surface was 1550 kg/m3, which was a bit smaller than those of sloped. After the tests, the excavator was used to toughen the inclination of the slope. However, the inclination was not very much steeper with maximum of 30�. After that two additional layers were laid and compacted with roof compactor. The method used for the fifth layer was the same as the day before (in sections from down to up). This method did not work very well, since the material tended to fall downwards. The compaction procedure for the sixth layer was different. First the upper part of the structure was pre-compacted by pressing the material with the compactor. Then the compaction continued with the similar procedure as in the first layer. The pre-compaction helped to keep the material from falling downwards. In addition the compaction of one section was done faster than previously which also seemed to enhance the compaction outcome. The measured inclination of the upper part of the slope was 28...29 �(1:1.9) and the lower part about 25�.

Finally two test cuttings were dug, one to the upper part of the slope and one to the lower part of the slope. In upper cutting Troxler, LDWT and Loadman tests were made. During toughening work the upper part of structure was disturbed. The lower part of the structure was supposed to be nearly undisturbed, thus one volumeter test was made from the lower cutting.

Figure 7. Compaction of the inclined layers Photo D. Adam.

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6.2 Compaction of the sloped test structure on the second test period (28.11.2005)

New layers were compacted with the multipurpose compactor (BMP851) over the six previously compacted layers in the first test period. The test was started with the filling of the cuttings and compaction of the topmost layer. The layer was in the beginning compacted with the vibratory roller to provide dense and even base for the new layers. The principal cross section of the structure is presented in the Figure 8.

Slope 1:1,5

2,0 m

Lower Cutting

33º28º

Upper Cutting

~24º

Figure 8. The principal cross section of sloped construction in the second test period.

Again the mixed material for the next layers was applied with the help of a normal excavator. This took approximately 5 minutes per layer. The control of layer thickness was done with measuring the height. The aim was to have a little thinner layer thickness than in the tests with the vibratory plates. The measured layer thickness before compaction varied between 170...230 mm (100...150 mm after compaction).

The first new layer (layer VII) was compacted in four rounds (VIIa-VIId) with the multipurpose compactor BMP851 (4 passing each round) in order to find out how many passes are required to gain the best compaction result. After that the same layer was compacted in three rounds (VIIe-VIIg) with the roller compactor in order to determine the maximum field density for the material. The observations of the compaction of the first layer were:

�� VIIa: The drum of the compactor was wet and the compactor had difficulties in climbing up the slope. The vibration mode could be used only when the compactor moved down the slope. During compaction the drum slid downwards. The dry densities achieved for the first layer were quite poor (Troxler dry densities were about 1415...1479 kg/m3) (Figure 9).

18

Figure 9. Compaction of the first layer I (first round). Photo P. Keto.

�� VIIb: After the second round, the material did not seem to compact much more (1380...1556 kg/m3). The difficulties observed in the first round continued.

�� VIIc: In order to stabilize the movement of the compactor and to be able to use the vibration, a cable wire was attached to a compactor. The other end was attached to the boom of the excavator. The compaction result gained after this round was the best so far (dry densities varied 1545...1713 kg/m3). Despite the help of the excavator, steering of the compactor was difficult (Figure 10).

19

Figure 10. Compaction with the help of a wire attached to the boom of the excavator. Photo P. Keto.

�� VIId: The material did not compact any more during the fourth round (in fact it seemed to re-loosen a little resulting in dry density range of 1516...1716 kg/m3). Therefore it was concluded that 4-6 passes (with the help of the excavator) was optimal for the material with the BMP851 compactor.

�� VIIe-VIIg: The following three compaction rounds were performed with the vibratory roller (Figure 11). The surface started to turn out to be wetter than before due to the amount of passes. The sliding of the compactor was also observed due to slippery surface. The maximum dry density achieved with the vibratory roller varied between 1639...1831 kg/m3.

After compaction of the first layer, two more layers were compacted with the multipurpose compactor (four passing per layer). The thickness of layer VII was 205...220 mm before the compaction. The surface dropped 60...70 mm after the compaction (to about 150 mm). The thickness of layer VIII was 170...220 mm before compaction. The dry densities of the layer VIII varied from 1499...1652 kg/m3 and for the layer IX 1543...1617 kg/m3. Four additional passes were applied for layer IX, but the compaction result enhanced only in the lower part of the layer.

20

The measured inclination of the topmost layer was 23.5-24°, which was leaner than the planned inclination was. After the test compaction two test cuttings were made (Figure 8). The upper one was dug with a shovel and the lower with the excavator. The volumeter tests were done from both of the cuttings. Besides these Loadman and Troxler tests were made from the lower cutting.

Figure 11. Compaction with the vibratory roller.

21

7 COMPACTION OF THE HORIZONTAL LAYERS

The parameters for the modelling were mainly measured from this structure, since the LDWT, Loadman or volumeter tests cannot be performed from inclined surfaces. The principal cross-section of the horizontal test construction is presented in Figure 12. The total thickness of the compacted construction was about 800 mm.

~0,8 m

Cutted surface

Figure 12. The principal cross section of horizontal construction.

Four layers were laid and compacted during the first day with the Dynapac LH700 vibratory plate. The uncompacted layer thickness of the first layer varied from 200 mm to 350 mm. The area for the horizontal test was approximately 2.5 x 3.5 m2 and it was done against the fringe slope. The compaction of one layer took approximately 10–15 minutes. After 2...3 passing, the resulting layer thickness for the first layer was about 200 mm. Volumeter test was performed from the second and the fourth layer after 5–6 passes. The material used for the third layer was a little too wet, since the material stuck to the compactor and had to be removed manually.

After the volumeter test on the second day, the fourth layer was recompacted. In the end the upper layer was cut. During the cutting the material started to slide along its layer surfaces.

23

8 LABORATORY TEST RESULTS

The grain size distribution of the crushed rock material, Proctor tests and triaxial tests were conducted to the tested bentonite - crushed rock mixture. Figure 13 presents the estimated grain size distribution of the crushed rock, while the proportion of bentonite is assumed to be 30 weight-%.

0

10

20

30

40

50

60

70

80

90

100

0.01 0.1 1 10

Gra in size (mm)

Passing

%

Figure 13. The estimated grain size distribution of the crushed rock based on the tests done for the test mixture with bentonite content of 30%.

The modified Proctor test of the mixture showed that the optimum water contents was 13.8% and the corresponding dry density was 1.97 g/cm3. The Proctor results are illustrated on the Figure 14.

1.6

1.7

1.8

1.9

2.0

2.1

11 12 13 14 15 16 17

Water content (%)

Dry

den

sity

g/c

m3

Figure 14. The water content / dry density curve of the bentonite - crushed rock 30 / 70 mixture.

24

The mixture is very sensitive to the excess water content. That can not be seen in the Proctor curve. The test results depend on the test. It is obvious that Proctor test overestimate the material properties.

The triaxial test

Triaxial tests results are presented in details in Appendix 16. The test specimens (3 pieces) were compacted at the moisture content of 10.5%. The specimens were saturated using 50 kPa pressure and the pressure head was 1 m (2–4 days). During saturation less than 10 g water in take was detected. The specimens were consolidated at least 6 hours. During consolidation the water did not flow out from the specimen except one specimen with confining pressure of 200 kPa.

The behavior of the specimen was similar to frictional soil according to the stress paths in q-p graph (Fig 15). The friction determined was 17.8° and cohesion 102 kPa. The saturation degree of the specimens was only 70% to be able to determine reliable effective strengths the saturation degree should be > 90%.

The weakest part of the specimens was the saturated part. Maximum shear stresses were achieved with high strain levels.

Normal stress

Cohesion = 102.2 kPa

Angel of friction = 17.8 o

Shake stress [kPa]

Nro Call Loading Pressure Speed

123

50 .015100 .015200 .015

1 2 3

Figure 15. Triaxial test results.

25

9 DISCUSSION

Water contents and densities

The measured water contents of the mixture mass before the test (10.10.2005 morning) was in average 12.2% and after the test (11.11.2005 afternoon) the average was 11.6%. After the test the water content was measured from both of the test structures and stack. The water contents measured with Troxler showed average water content of 12%. The laboratory measured water contents of the material on the 28th of November was measured only in two points and the values varied from 12.3...15.1%, but the water contents according to Troxler were about the same 11.8%. So, the mixture was in nearly the same water content after 10 days storing as it was in the beginning.

The mixed material was very sensitive to the excess of water. If the water content was higher than about 13...13.5%, the material changed into lumpy consistent and it stuck to the compaction plate. The stuck mass had to be removed manually. This happened in both test constructions: in sloped test from time to time and in horizontal test in layer III. The compaction of the lumpy mass was more difficult and much slower than the mass in the optimum water content. Yet, the reached dry densities were about the same as in other layers (Tables 1 and 2). Similar problems were not observed with the multipurpose compactor.

The densities of the layers with Troxler were measured in three different depths: 50 mm, 100 mm and 150 mm. The densities were measured mainly from three different points. The average density measurement results are presented in Tables 1 and 2. The densities presented in this study are average values of the measurements in different depths and points, because the densities depend on the measuring depth only in average 1.9–3.9% (Figure 16).

26

Table 1. The average densities of the sloped test structure.

Layer and number of passes

Average dry density (Troxler) kg/m3

Sand volumeter dry density (kg/m3)

Test date

III / 6...8 1633 - 10.11.2005

IV / 3...4 1633 - 10.11.2005

V / 3...4 1546 - 11.11.2005

VI / 3...4 1572 - 11.11.2005

VI / 3...4 Lower cutting 1590 1 390 11.11.2005

VIIa 1440 - 28.11.2005

VIIb 1469 - 28.11.2005

VIIc 1605 - 28.11.2005

VIId 1595 - 28.11.2005

VIIe 1748 - 28.11.2005

VIIf 1646 - 28.11.2005

VIIg 1770 - 28.11.2005

VIII / 3...4 1582 - 28.11.2005

IX / 6...8 1672 - 28.11.2005

IX / lower cutting 1552 1 415 28.11.2005

IX / upper cutting (shovel) 1618 1 435 28.11.2005

27

Table 2. The densities of the horizontal test structure.

Layer and passes Dry density (Troxler) kg/m3

Sand volumeter dry density (kg/m3)

Date

I /4...6 1561 - 10.11.2005

I / 6...9 1670 - 10.11.2005

II /2...3 1548 - 10.11.2005

II / 4...6 1526 - 10.11.2005

II / 6...8 1587 1 541 10.11.2005

III / 2...3 1588 - 10.11.2005

III / 4...6 1613 - 10.11.2005

III / 6...9 1614 - 10.11.2005

IV / 2...3 1464 - 10.11.2005

IV / 4...6* 1616 1 722 10.11.2005

IV / 6...8* 1746 - 11.11.2005

Cutting* - 1 600 11.11.2005

*The test was performed in the morning from the surface that had been compacted in the previous day.

0

20

40

60

80

100

120

140

160

1540 1560 1580 1600 1620 1640 1660

Density (g/cm3)

Dep

th, m

m

Slope DD average 11.11.2005

Horizontal DD 11.11.2005 averge

Slope DD average 28.11.2005

Figure 16. The average Troxler densities in sloped and horizontal test structures in different depths.

28

Deflections and E modulus

The deflections were measured with LDWT and Loadman. The average stiffness moduli (E) measured for the horizontal test structure with Loadman and with LDWT are presented in Table 3. All LDWT results are presented in Appendix 9. Because deflection measurements can be made only from an even surface, stiffness modulus of the inclined structures were measured only from the cuttings. The average value of the LDWT stiffness modulus of inclined measurements (2 points) was 35.3 MPa and of the horizontal structure after 6...9 passes 70.4 MPa. The corresponding Loadman stiffness modulus of the horizontal structure after 6...9 passes was 66.7 MPa and of the inclined structure with multipurpose and roller compaction 69.4 MPa.

Table 3. The average LDWT and Loadman results of the horizontal test structure.

Layer and passes

LDWT deflection,

mm

LDW E modulus MN/m2

Loadman deflection,

mm

Loadman E modulus MN/m2

I /2...3 0.33 67.6 1.48 53.7

I / 4...6 0.22 101.4 0.95 83.6

I / 6...9 0.23 96.2 1.13 69.9

II /1 2.55 8.8 - -

II /2...3 0.41 54.9 - -

II / 4...6 0.35 64.5 - -

II /6...9 0.27 84.3 - -

III /2..3 0.35 65.2 - -

III /4...6 0.27 84.0 - -

III / 6...9 0.28 81.8 1.19 66.7

IV/2...3 0.35 64.5 - -

IV / 4...6 0.33 68.8 1.07 75.9

IV/6...9 0.27 82.1 - -

IV / 6...9 (next morning)

0.39 60.6 0.84 93.7

IV / 6...9 - - 1.07 73.9

Layers removed 0.29 77.9 - -

Compaction of the sloped test structures in the first test period

The compaction tests proved that the optimum amount of passes was about 4 to 6 passes per layer. More compaction did not improve the density or even made it worse (for example Table 1). The total average of the dry densities was 1572 kg/m

3 and wet

29

densities 1742 kg/m3. The highest dry density measured was 1793 kg/m3 and the lowest only 1342 kg/m3. In general, the densities achieved were somewhat lower than the ones gained in the Prototype repository (for the sloped structure with a coarser material and a heavier compactor). Only one sand volumeter test was made and it gave dry density of 1390 kg/m3, which is smaller than the dry densities of the Troxler tests.

The roof compactor seemed to work relatively well. The water content of the mass varied, and thus the material for layers III and IV stuck to the bottom of the compactor plate from time to time. The interaction between the carrier and the plate requires further development. The driver of the Gradall carrier had difficulties keeping the correct static pressure to the soil as well as full contact between the whole width of the foot plate and the soil, which is important for a good compaction result. Therefore the roof compactor should be provided with functions for constant pressure of the foot plate to the soil as well as an automatic adjustment for contact to the soil over the whole width of the foot plate. Otherwise the telescope boom seemed to be suitable for backfilling of inclined layers. Despite of the efforts to toughen the inclination of the slope to 33–34� the measured inclination was about was 28� (1:1.9). Besides these, the speed of the roof compactor could also be increased without lower compaction result.

Compaction of the sloped test structures in the second test period

In the second test period the heavier roller with weight of 13 t performed quite well and the achieved dry densities were quite promising varying between 1639...1831 kg/m3. A thin film of water was occasionally observed on the compacted surface with both compactor, but in a bigger amount with the roller 13 t compactor. The separation of water may indicate that the water content may have been too high for the heavy compactor. However, based on the compaction results, the effects of water separation were small or insignificant.

Both the roller and multipurpose compactor were sliding on the slippery surface. For a stable compaction work the multipurpose compactor had to be attached to a boom of an excavator with a help of cable wire. Despite the help of the excavator, steering of the compactor was difficult.

Additional layers were compacted with the multipurpose compactor (four passing per layer). The thickness of layer VII was 205...220 mm before the compaction. The surface dropped 60...70 mm after the compaction (to ~150 mm). The thickness of layer VIII was 170...220 mm before compaction. The dry densities of the layer VIII varied from 1499...1652 kg/m3 and for layer IX 1543...1617 kg/m3. The inclination of the topmost layer was 23.5-24°, which was leaner than the target inclination.

30

Compaction of the horizontal layers

The compaction tests proved that also in this test structure the optimum amount of passes was about 4 to 6 passes per layer. More compaction did not improve the density or even made it worse (see Tables 2 and 3). The total average of the dry densities was bigger than in the sloped test structure 1612 kg/m3 and wet densities 1805 kg/m3. The highest dry density measured was 1809 kg/m3 and the lowest was 1362 kg/m3.

Three sand volumeter tests were made. The dry densities varied from 1540 to 1720 kg/m3. These densities can be considered promising even though the target densities were not achieved.

When the test structure was cutted in the end of the test, the material slid along layer surfaces. This revealed that the contact between the layers was distinct implying insufficient interlocking between them. The sliding reached out to surface of the second layer. Figure 17 shows the situation after cutting. The layers II, III and IV can easily be detected. One volumeter test was conducted also from the revealed surface. It is possible that the cutting disturbed the structure a bit.

Figure 17. The cutted surface of the horizontal construction. Photo D. Adam.

31

10 CONCLUSIONS

A tabled comparison of the tested equipments and methods is presented in Table 4.

Table 4. The comparison of the tested compaction methods.

Test structure / equipment

Horizontal / LH700

Inclined / roof compactor

Inclined / roller 13 t

Inclined / BMP851

Measured average dry

density (kg/m3) 1655 1572 1744 1594

Estimated work efficiency class ++ Efficient ± Relatively

inefficient +++Very efficient + Tolerable

Advantages Even

compaction results

Can be used in the close areas like upper part

of tunnel

Efficient method

The best interlocking of

the layers

Weaknesses Insufficient interlocking

between layers

Insufficient interlocking

between layers

Too steep slope

Steering problems

Too short feet, can not be used in steep slope without help

Further development

A heavier compactor

Better control of the constant

pressure Work

efficiency

Optimum water content needs to be

tested for this method.

A heavier compactor Longer feet Steering in

slope

The main findings of the field test are following:

�� The mixture was in nearly the same water content condition after 18 days storing as it was in the beginning (according to Troxler measurements no change, according to laboratory measurements an increase of 0.1...1.9%).

�� The target thickness of the layers was 200...250 mm. It is relatively difficult to control the layer thickness of the inclined layers. In both test structures the layer thickness was probably too thick to achieve the maximal density for the material.

�� The mixture is very sensitive to the water content. If the water content exceeds the optimum water content by 1%, the compaction work will be much slower and ineffective. Yet, it is possible that this does not affect so much on the reached densities.

�� The needed modelling data was obtained from the test. �� The densities in the upper part (depth 50 mm) of the layer were somewhat higher

than in the deeper part (150 mm). The difference was in average from 1.9% to 3.9%.

32

�� The target dry density of about 1900 kg/m3 was reached in neither structure. Yet, the

results for the horizontal layer compaction are promising (average dry density 1612 kg/m

3). The heavier roller in the sloped structure seemed to work also well and the

achieved dry densities after about 6 passes were quite good 1766 kg/m3.

�� A heavier padfoot roller (than the 1.5 t multipurpose compactor) would probably have given better compaction effect. The feet of the multipurpose compactor should have been longer.

�� The inclination of the slope (23...24�) was too steep for the tested multicompactor. The use of the multipurpose roller for compacting inclined layers is possible with the help of the cable wire mounted to the roof or a pushing device of the roller. Otherwise it is impossible to keep the compaction process stable and to be able to steer the compactor. The problems with steering and sliding caused also that the efficiency and average densities of the method were not as good as with roller.

�� The most efficient way to get best results with inclined layers is to use a heavy roller. Nearly as good results could be achieved with a vibratory plate on the horizontal layer. The modified roof compactor was the slowest method with the lowest compaction degrees. However, this equipment is the only one that can be used for the compacting the roof of the tunnel. In addition, the efficiency of the plate can be further developed, since this was just a prototype.

�� The interlocking between layers was insufficient for roof compactor, vibratory plate (LH700) and heavy roller.

�� The equipment used were not optimized in order gain as high dry density as possible and therefore higher dry densities (that gained in these field-tests) can be expected with optimized equipment.

�� Thus, more research is needed to develop the compaction methods further and to optimize the layer thickness and water content. The further development will base on these results and the modelling including for example the working order or the optimization of the vibrating equipment.

�� Even though the highest density requirements of the repository tunnel were not achieved, the test gave many positive results and proved that a relatively compact tunnel backfilling can be achieved with these methods. The used methods could be used in the compaction of backfilling of other deep excavations.

The completing conclusions of numerical simulations as well as field and laboratory tests are presented in appendix 17.

33

REFERENCES

Gunnarsson, D., Börgesson, L., Keto, P., Tolppanen, P. & Hansen, J. 2004. Backfilling of the Deep Repository. Assessment of backfill concepts. Posiva Oy, Eurajoki. Posiva working Report 2003-77, 2003.

Keto P., Kuula-Väisänen P. and Ruuskanen J. "Effect of material parameters on the compactibility of the backfill materials", Posiva working report 2006-34, 2006.

35

APPENDICES

Appendix 1. The foot compactor (Halltek's vibratory plate).

Appendix 2. The test results of volumeter tests (VTT)

Appendix 3. The test results of Loadman tests (VTT)

Appendix 4. The test results of Troxler tests on the horizontal embankment (Ekokem - Palvelut Oy)

Appendix 5. The test results of Troxler tests on the sloped structure (Ekokem - Palvelut Oy)

Appendix 6. The test results of water content tests (Ekokem - Palvelut Oy)

Appendix 7. The grain size distribution of the crushed rock sample (Ekokem - Palvelut Oy)

Appendix 8. The mix data of the bentonite - crushed rock mixture (Ekokem - Palvelut Oy)

Appendix 9. The test results of LDWT tests (Dietmar Adam)

Appendix 10. The technical data of Bomag multicompactor BMP851 http://www.bomag.com/ext_resource/americas/light/BMP851_4pg.pdf

Appendix 11. The technical data of Bomag vibratory roller BW211-D3 http://www.bomag.com/ext_resource/americas/heavy/BW211_4pg.pdf

Appendix 12. The technical data of Dynapac LH700 compaction plate http://www.dynapac.com/templates/product____471.aspx

Appendix 13. The technical data of Gradall XL3300 excavator with a telescopic boom http://www.gradall.com/downloads/spec_sheets/xl3300ss.pdf

Appendix 14. The technical data of the Light Drop Weight (LDWT) tester http://www.kesslerdcp.com/PDFs/ZFG2000.pdf

Appendix 15. The product data of the portable Fall Weight Deflectometer Loadman http://www.al-engineering.fi/en/loadman.html

Appendix 16. Laboratory analyses for compaction properties of backfill materials concerning in situ compaction project, Tampere University of Technology

36

Appendix 17. Technical report. Backfilling and closure of the deep repository. Roof compactor. Laboratory and field tests. Numerical simulations. (Dietmar Adam)

37 APPENDIX 1

Tested foot plate

39 APPENDIX 2

The test results of sand volumeter tests (VTT)

The density of the volumeter sand 1 485 kg/m3 Mass of the sand 6 000 g

A. Sloped structure, vibrating plate 11.11.2005 Dry mass of digged material 1.4611 kg

Volume of the hole 1051.4 cm3 Water content 12.75 %

Dry density of digged material 1390 kg/m3

B. Sloped structure, multicompator 28.11.2005 Vol.2Dry mass of digged material 1.7070 kg



C. Sloped structure, multicompactor 28.11.2005 Vol.1Dry mass of digged material 1.4860 kg



Horizontal test structure: 1 . Second layer 10.11.2005

Dry mass of digged material 1.3286 kg



2. 4 th layer 11.11.2005 Dry mass of digged material 1.6623 kg



3. Cutted surface, about 2nd layer 11.11.2005 Dry mass of digged material 1.8241 kg


Dry density of dug material 1600 kg/m3

41 APPENDIX 3

The test results of Loadman tests (VTT)

Loadman measurements VTT/ LKT Date 10112005 Horizontal test embankment

The bottom asphalt layer weight 9.8 kg

Diameter Measurement Calibration Deflection,

mm

average calibrated deflection,

mm

E modulus MN/m2

average E MN/m2

132 0.46 0.88889 0.408889 440.2 132 0.76 0.88889 0.675556 266.4 132 0.51 0.88889 0.453333 397.1 132 0.49 0.88889 0.435556 413.3 132 0.45 0.88889 0.4 0.47 450.0 393.4

1st layer 2 passes 300 1.81 0.88889 1.608889 48.9 300 1.65 0.88889 1.466667 53.7 300 1.46 0.88889 1.297778 60.7 300 1.48 0.88889 1.315556 59.9 300 1.95 0.88889 1.733333 1.48 45.4 53.7

1st layer 4 passes 300 1.01 0.88889 0.897778 87.7 300 1.04 0.88889 0.924444 85.2 300 1.19 0.88889 1.057778 74.4 300 1.07 0.88889 0.951111 82.8 300 1.01 0.88889 0.897778 0.95 87.7 83.6

1st layer 6 passes 300 1.37 0.88889 1.217778 64.7 300 1.24 0.88889 1.102222 71.4 300 1.25 0.88889 1.111111 70.9 300 1.25 0.88889 1.111111 70.9 300 1.24 0.88889 1.102222 1.13 71.4 69.9

3rd layer 6 passes 300 1.27 0.88889 1.128889 69.8 300 1.25 0.88889 1.111111 70.9 300 1.27 0.88889 1.128889 69.8 300 1.41 0.88889 1.253333 62.8 300 1.47 0.88889 1.306667 1.19 60.3 66.7

4th layer 6 passes 300 1.42 0.88889 1.262222 62.4 bad contact 300 1.09 0.88889 0.968889 81.3 300 1.25 0.88889 1.111111 70.9 300 1.6 0.88889 1.422222 55.4 300 0.96 0.88889 0.853333 92.3 300 1.11 0.88889 0.986667 1.07 79.8 75.9

42 APPENDIX 3

Diameter Measurement Calibration Deflection,

mm

average calibrated deflection,

mm

E modulus MN/m2

average E MN/m2

4th layer 6 passes Friday morning test date 11112005 300 0.96 0.88889 0.853333 92.3 300 0.93 0.88889 0.826667 95.3 300 0.94 0.88889 0.835556 94.2 300 0.93 0.88889 0.826667 95.3 300 0.97 0.88889 0.862222 0.84 91.3 93.7

4th layer 8 passes 300 1.19 0.88889 1.057778 74.4 300 1.22 0.88889 1.084444 72.6 300 1.22 0.88889 1.084444 72.6 300 1.14 0.88889 1.013333 77.7 300 1.23 0.88889 1.093333 1.07 72.0 73.9

Loadman measurements PKe Date 28112005 Horizontal test embankment weight 9.8 kg

Diameter Measurement Calibration DeflectionE

modulus average E average

deflection Sloped layer IX lower cutting mm MN/m2 MN/m2 mm

300 1.28 0.88889 1.1377778 69.2 300 1.34 0.88889 1.1911111 66.1 300 1.31 0.88889 1.1644444 67.6 300 1.28 0.88889 1.1377778 69.2 300 1.26 0.88889 1.12 70.3 68.5 1.15

Sloped layer IX lower cutting

300 1.28 0.88889 1.1377778 69.2 300 1.26 0.88889 1.12 70.3 300 1.37 0.88889 1.2177778 64.7 300 1.10 0.88889 0.9777778 80.5 300 1.33 0.88889 1.1822222 66.6 70.3 1.13

43 APPENDIX 4

The test results of Troxler tests on the horizontal embankment (Ekokem - Palvelut Oy) DD = dry density, WD = wet density

Date Depth Sample DD kg/m3 WD kg/m3 Water Water DD kg/m3 corrected Remarks

I layer 4...6 Compaction LH700 10.11.2005 20 cm 1 1414 1646 16.4% 11.4% 1478 10.11.2005 15 cm 1 1303 1502 15.2% 10.2% 1363 10.11.2005 20 cm 2 1437 1629 13.4% 8.4% 1503 10.11.2005 15 cm 2 1410 1623 15.1% 10.1% 1474 10.11.2005 15 cm 1 1717 1939 12.9% 7.9% 1797 10.11.2005 15 cm 2 1571 1822 16.0% 11.0% 1641 10.11.2005 15 cm 3 1594 1835 14.9% 9.9% 1670

average 1492 1714 14.8% 9.8% 1561 stdev 141 154 1.3% 1.3% 148

I layer 6...9 Compaction LH700 10.11.2005 15 cm 4 1594 1854 16.4% 11.4% 1664 10.11.2005 15 cm 5 1604 1843 14.9% 9.9% 1677

average 1599 1849 15.7% 10.7% 1671 stdev 7 8 1.1% 1.1% 9

II layer 2...3 Compaction LH700 10.11.2005 15 cm 6 1456 1688 15.9% 10.9% 1522 10.11.2005 15 cm 7 1502 1728 15.0% 10.0% 1571 10.11.2005 15 cm 8 1484 1723 16.1% 11.1% 1551

average 1481 1713 15.7% 10.7% 1548 stdev 23 22 0.6% 0.6% 25

II layer 4...6 Compaction LH700 10.11.2005 15 cm 9 1428 1649 15.7% 10.7% 1490

10.11.2005 15 cm 10 1454 1723 18.5% 13.5% 1518 Volymete

r test 10.11.2005 15 cm 11 1503 1745 16.1% 11.1% 1571

average 1462 1706 16.8% 11.8% 1526 stdev 38 50 1.5% 1.5% 41

II layer 6...9 Compaction LH700 10.11.2005 15 cm 12 1514 1780 17.5% 12.5% 1582 10.11.2005 10 cm 12 1542 1816 17.7% 12.7% 1611 10.11.2005 5 cm 12 1585 1863 17.6% 12.6% 1655 10.11.2005 15 cm 13 1444 1711 18.5% 13.5% 1507 10.11.2005 10 cm 13 1461 1743 19.3% 14.3% 1525 10.11.2005 5 cm 13 1494 1771 18.5% 13.5% 1560 10.11.2005 15 cm 14 1499 1789 19.3% 14.3% 1565 10.11.2005 10 cm 14 1548 1836 18.6% 13.6% 1616 10.11.2005 5 cm 14 1592 1893 18.9% 13.9% 1662

average 1520 1800 18.4% 13.4% 1587 stdev 51 58 0.7% 0.7% 54 III layer 2...3 Compaction LH700

10.11.2005 15 cm 15 1495 1721 15.1% 10.1% 1563 10.11.2005 10 cm 15 1513 1769 16.9% 11.9% 1581 10.11.2005 5 cm 15 1549 1797 16.0% 11.0% 1619

average 1519 1762 16.0% 11.0% 1588 stdev 27 38 0.9% 0.9% 29

III layer 4...6 Compaction LH700 10.11.2005 15 cm 16 1496 1766 18.1% 13.1% 1561 10.11.2005 10 cm 16 1486 1785 20.1% 15.1% 1551 10.11.2005 5 cm 16 1498 1812 20.9% 15.9% 1563

44 APPENDIX 4

Date Depth Sample DD kg/m3 WD kg/m3 Water Water DD kg/m3 corrected Remarks

10.11.2005 15 cm 17 1581 1848 16.9% 11.9% 1651 10.11.2005 10 cm 17 1600 1887 17.9% 12.9% 1671 10.11.2005 5 cm 17 1607 1903 18.4% 13.4% 1678

average 1545 1834 18.7% 13.7% 1613 stdev 57 55 1.5% 1.5% 60

III layer 6...9 Compaction LH700 11.11.2005 15 cm 18 1521 1804 18.6% 13.6% 1588 11.11.2005 10 cm 18 1500 1804 20.3% 15.3% 1565 11.11.2005 5 cm 18 1553 1834 18.1% 13.1% 1622 11.11.2005 15 cm 19 1517 1801 18.7% 13.7% 1584 11.11.2005 10 cm 19 1586 1831 15.4% 10.4% 1659 11.11.2005 5 cm 19 1598 1864 16.6% 11.6% 1670

average 1546 1823 18.0% 13.0% 1614 stdev 40 25 1.7% 1.7% 43

IV layer 2...3 Compaction LH700 11.11.2005 15 cm 20 1510 1776 11.11.2005 10 cm 20 1563 1838 17.6% 12.6% 1632 11.11.2005 5 cm 20 1592 1869 17.4% 12.4% 1663

average 1411 1661 16.2% 11.7% 1464 stdev 456 543 5.3% 3.8% 501

IV layer 4...6 Compaction LH700 11.11.2005 15 cm 21 1492 1732 16.1% 11.1% 1559 11.11.2005 10 cm 21 1517 1753 15.5% 10.5% 1586 11.11.2005 5 cm 21 1521 1784 17.3% 12.3% 1589 11.11.2005 15 cm 22 1556 1817 16.8% 11.8% 1625 11.11.2005 10 cm 22 1571 1853 17.9% 12.9% 1641 11.11.2005 5 cm 22 1617 1892 17.0% 12.0% 1689 11.11.2005 15 cm 23 1559 1844 18.3% 13.3% 1628 11.11.2005 10 cm 23 1538 1848 20.2% 15.2% 1604 11.11.2005 5 cm 23 1580 1865 18.0% 13.0% 1650

average 1550 1821 17.5% 12.5% 1619 stdev 38 54 1.4% 1.4% 39

IV layer 6...9 Compaction LH700 11.11.2005 15 cm 24 1589 1847 16.2% 11.2% 1661 11.11.2005 10 cm 24 1622 1861 14.7% 9.7% 1696 11.11.2005 5 cm 24 1652 1905 15.3% 10.3% 1727 11.11.2005 15 cm 25 1710 1985 16.1% 11.1% 1787 11.11.2005 10 cm 25 1722 2002 16.3% 11.3% 1799 11.11.2005 5 cm 25 1732 2033 17.4% 12.4% 1809

average 1671 1939 16.0% 11.0% 1746 stdev 59 78 0.9% 0.9% 61

45 APPENDIX 5

The test results of Troxler tests on the sloped structure (Ekokem - Palvelut Oy)

Date Depth Sample DD WD Water Water DD kg/m3 Remarks

III layer Compaction kg/m3 kg/m3 corrected corrected Roof compactor 10.11.2005 15 cm 1 1510 1737 15.1% 10.1% 1578 10.11.2005 10 cm 1 1507 1741 15.5% 10.5% 1576 10.11.2005 5 cm 1 1533 1771 15.6% 10.6% 1601 10.11.2005 15 cm 2 1300 1514 16.5% 11.5% 1358 10.11.2005 10 cm 2 1282 1503 17.2% 12.2% 1340 10.11.2005 5 cm 2 1284 1496 16.5% 11.5% 1342 10.11.2005 15 cm 3 1426 1653 15.9% 10.9% 1491 10.11.2005 10 cm 3 1455 1684 15.7% 10.7% 1521 10.11.2005 5 cm 3 1484 1724 16.2% 11.2% 1550 average 1420 1647 16.0% 11.0% 1484 stdev 104 112 0.6% 0.6% 108 III layer Compaction Roof compactor 10.11.2005 15 cm 4 1546 1836 18.7% 13.7% 1615 10.11.2005 10 cm 4 1558 1856 19.1% 14.1% 1627 10.11.2005 5 cm 4 1602 1872 16.9% 11.9% 1673 10.11.2005 15 cm 5 1581 1821 15.2% 10.2% 1652 10.11.2005 10 cm 5 1589 1836 15.5% 10.5% 1662 10.11.2005 5 cm 5 1604 1864 16.2% 11.2% 1676 10.11.2005 15 cm 6 1519 1749 15.2% 10.2% 1587 10.11.2005 10 cm 6 1533 1775 15.8% 10.8% 1602 10.11.2005 5 cm 6 1534 1789 16.6% 11.6% 1603

average 1563 1822 16.6% 11.6% 1633 stdev 32 42 1.4% 1.4% 34 IV layer Compaction Roof compactor 10.11.2005 15 cm 7 1424 1642 15.3% 10.3% 1489 10.11.2005 10 cm 7 1421 1665 17.1% 12.1% 1485 10.11.2005 5 cm 7 1463 1690 15.5% 10.5% 1529 10.11.2005 15 cm 8 1453 1714 18.0% 13.0% 1517 10.11.2005 10 cm 8 1474 1712 16.2% 11.2% 1540 10.11.2005 5 cm 8 1500 1750 16.6% 11.6% 1568 10.11.2005 15 cm 9 1470 1716 16.8% 11.8% 1535 10.11.2005 10 cm 9 1486 1742 17.2% 12.2% 1553 10.11.2005 5 cm 9 1469 1743 18.6% 13.6% 1534

average 1462 1708 16.8% 11.8% 1633 stdev 26 37 1.1% 1.1% 34

IV layer Compaction Roof compactor 10.11.2005 15 cm 10 1624 1920 18.2% 13.2% 1696 10.11.2005 10 cm 10 1687 1969 16.7% 11.7% 1763 10.11.2005 5 cm 10 1715 1999 16.5% 11.5% 1793 10.11.2005 15 cm 11 1395 1621 16.2% 11.2% 1458 10.11.2005 10 cm 11 1436 1642 14.4% 9.4% 1501 10.11.2005 5 cm 11 1424 1650

average 1547 1800 16.4% 11.4% 1642 stdev 144 180 1.4% 1.4% 153

46 APPENDIX 5

Date Depth Sample DD WD Water Water DD kg/m3 Remarks

IV layer Same points, remeasured Roof compactor

11.11.2005 15 cm 12 1511 1780 17.8% 12.8% 1578 11.11.2005 10 cm 12 1558 1819 16.8% 11.8% 1627 11.11.2005 5 cm 12 1626 1865 14.7% 9.7% 1700 11.11.2005 15 cm 13 1565 1856 18.6% 13.6% 1634 11.11.2005 10 cm 13 1593 1869 17.3% 12.3% 1664 11.11.2005 5 cm 13 1649 1920 16.4% 11.4% 1724 11.11.2005 15 cm 14 1508 1756 16.4% 11.4% 1576 11.11.2005 10 cm 14 1495 1767 18.2% 13.2% 1561 11.11.2005 5 cm 14 1485 1767 19.0% 14.0%

average 1554 1822 17.2% 12.2% 1633 stdev 59 58 1.3% 1.3% 60

IV layer Upper cutting 11.11.2005 15 cm 15 1512 1766 16.8% 11.8% 1580 11.11.2005 10 cm 15 1472 1765 19.3% 14.3% 1544 11.11.2005 5 cm 15 1462 1725 18.0% 13.0% 1527

average 1482 1752 18.0% 13.0% 1550 stdev 26 23 1.3% 1.3% 27

V layer

Compaction with a new technique Roof compactor

11.11.2005 15 cm 16 1411 1659 17.5% 12.5% 1475 Upper part of slope11.11.2005 10 cm 16 1405 1655 17.7% 12.7% 1469 Upper part of slope11.11.2005 5 cm 16 1401 1660 18.5% 13.5% 1463 Upper part of slope11.11.2005 15 cm 17 1518 1795 18.3% 13.3% 1584 Upper part of slope11.11.2005 10 cm 17 1576 1826 15.9% 10.9% 1647 Upper part of slope11.11.2005 5 cm 17 1568 1841 17.4% 12.4% 1638 Upper part of slope11.11.2005 15 cm 18 1464 1710 16.8% 11.8% 1530 Upper part of slope11.11.2005 10 cm 18 1490 1704 14.4% 9.4% 1558 Upper part of slope11.11.2005 5 cm 18 1489 1706 14.6% 9.6% 1557 Upper part of slope

average 1480 1728 16.8% 11.8% 1546 stdev 67 73 1.5% 1.5% 69

VI layer Compaction Roof compactor 11.11.2005 15 cm 19 1514 1746 15.4% 10.4% 1582 Lower part of slope11.11.2005 10 cm 19 1523 1758 15.5% 10.5% 1591 Lower part of slope11.11.2005 5 cm 19 1529 1772 15.9% 10.9% 1598 Lower part of slope11.11.2005 15 cm 20 1525 1771 16.1% 11.1% 1594 Lower part of slope11.11.2005 10 cm 20 1571 1817 15.6% 10.6% 1643 Lower part of slope11.11.2005 5 cm 20 1600 1834 14.6% 9.6% 1673 Lower part of slope11.11.2005 15 cm 21 1418 1644 15.9% 10.9% 1482 Lower part of slope11.11.2005 10 cm 21 1415 1645 16.3% 11.3% 1478 Lower part of slope11.11.2005 5 cm 21 1441 1653 14.7% 9.7% 1507 Lower part of slope

average 1504 1738 15.6% 10.6% 1572 stdev 66 73 0.6% 0.6% 69

VI layer Lower cutting 11.11.2005 15 cm 21 1541 1743 13.1% 8.1% 1612 11.11.2005 10 cm 21 1520 1737 14.3% 9.3% 1589 11.11.2005 5 cm 21 1501 1723 14.8% 9.8% 1569 average 1521 1734 14.1% 9.1% 1590

stdev 20 10 0.9% 0.9% 22

47 APPENDIX 5

Date Depth Sample DD WD Water Water DD Remarks VI layer cm point % corrected corrected

Phase VIIa Compaction kg/m3 kg/m3 kg/m3 About 4 passes 28.11.2005 15 22 1363 1560 14.4 9.4 1426

28.11.2005 10 22 1355 1583 16.9 11.9 1415 compactor BMP

851 28.11.2005 5 22 1414 1631 15.3 10.3 1479

average 1377 1591 15.5 10.5 1440 stdev 32 36 1.3 1.3 34

Phase VIIb Compaction compactor BMP

851 28.11.2005 15 23 1321 1544 16.9 11.9 1380 28.11.2005 10 23 1380 1595 15.6 10.6 1442 28.11.2005 5 23 1350 1562 15.7 10.7 1411 28.11.2005 15 24 1436 1670 16.4 11.4 1499 28.11.2005 10 24 1460 1703 16.7 11.7 1525 28.11.2005 5 24 1489 1747 17.3 12.3 1556

average 1406 1637 16.4 11.4 1469 stdev 66 82 0.7 0.7 69

Phase VIIc Compaction

28.11.2005 15 25 1478 1708 15.6 10.6 1545 compactor BMP

851 28.11.2005 10 25 1581 1794 13.5 8.5 1654 28.11.2005 5 25 1637 1869 14.1 9.1 1713 28.11.2005 15 26 1440 1677 16.4 11.4 1505 28.11.2005 10 26 1500 1734 15.5 10.5 1569 28.11.2005 5 26 1574 1825 16.0 11.0 1644

average 1535 1768 15.2 10.2 1605 stdev 74 74 1.1 1.1 78

Phase VIId Compaction compactor BMP

851 28.11.2005 15 27 1451 1696 16.9 11.9 1516 28.11.2005 10 27 1493 1728 15.7 10.7 1561 28.11.2005 5 27 1543 1804 16.9 11.9 1612 28.11.2005 15 28 1493 1737 16.3 11.3 1561 28.11.2005 10 28 1539 1811 17.7 12.7 1607 28.11.2005 5 28 1642 1893 15.3 10.3 1716

average 1527 1778 16.5 11.5 1595 stdev 66 72 0.9 0.9 69

Phase VIIe Compaction compactor BMP

851

28.11.2005 15 29 1408 1657 17.7 12.7 1470

upper part of the slope

Disqualified

28.11.2005 10 29 1438 1692 17.7 12.7 1502


Disqualified

28.11.2005 5 29 1534 1809 17.9 12.9 1602


Disqualified 28.11.2005 15 30 1571 1885 20.0 15.0 1639 middle of the slope28.11.2005 10 30 1644 1943 18.2 13.2 1716 middle of the slope

48 APPENDIX 5


Phase VIIa Compaction kg/m3 kg/m3 kg/m3 About 4 passes 28.11.2005 5 30 1750 2046 16.9 11.9 1828 middle of the slope

28.11.2005 15 31 1633 1939 18.7 13.7 1705 lower part of the

slope 28.11.2005 10 31 1693 2002 18.3 13.3 1767 28.11.2005 5 31 1754 2075 18.3 13.3 1831

average 1674 1982 18.4 13.4 1748 stdev 126 148 0.9 0.9 131

Phase VIIf Compaction compactor roller

13tn 28.11.2005 15 32 1566 1830 16.9 11.9 1635 28.11.2005 10 32 1587 1884 18.7 13.7 1657

average 1577 1857 17.8 12.8 1646 stdev 15 38 1.3 1.3 15

Phase VIIg Compaction

28.11.2005 15 33 1647 1920 16.6 11.6 1720

roughing, new mass, compaction

roller 13 tn 28.11.2005 10 33 1690 1963 16.2 11.2 1766 28.11.2005 5 33 1724 1984 15.1 10.1 1802 28.11.2005 15 34 1648 1957 18.8 13.8 1720 28.11.2005 10 34 1726 2010 16.5 11.5 1803 28.11.2005 5 34 1733 2032 17.3 12.3 1809

average 1695 1978 16.7 11.7 1770 stdev 39 40 1.2 1.2 42

VII layer Compaction compactor roller

13tn 28.11.2005 15 35 1690 2010 19.0 14.0 1763 28.11.2005 10 35 1766 2059 16.6 11.6 1845 28.11.2005 5 35 1754 2073 18.2 13.2 1831

average 1737 2047 17.9 12.9 1813 stdev 41 33 1.2 1.2 44

VIII layer Compaction compactor BMP

851 28.11.2005 10 36 1435 1680 17.1 12.1 1499

28.11.2005 5 36 1502 1735 15.5 10.5 1570

water content (laboratory)

12.3% upper part of the slope

28.11.2005 10 37 1538 1778 15.6 10.6 1608

28.11.2005 5 37 1581 1827 15.6 10.6 1652

water content (laboratory)

15.1% upper part of the slope

average 1514 1755 15.9 10.9 1582 stdev 62 63 0.8 0.8 65

IX layer Compaction compactor BMP

851 28.11.2005 15 38 1491 1718 15.2 10.2 1559 28.11.2005 10 38 1484 1730 16.6 11.6 1550 28.11.2005 5 38 1548 1811 17.0 12.0 1617

49 APPENDIX 5


Phase VIIa Compaction kg/m3 kg/m3 kg/m3 About 4 passes 28.11.2005 15 39 1500 1776 18.4 13.4 1566 28.11.2005 10 39 1478 1751 18.5 13.5 1543 28.11.2005 5 39 1522 1788 17.5 12.5 1589

average 1504 1762 17.2 12.2 1571 stdev 27 36 1.2 1.2 28

IX layer Compaction compactor BMP

851 28.11.2005 15 40 1567 1810 15.5 10.5 1638 28.11.2005 10 40 1546 1786 15.3 10.3 1619 28.11.2005 5 40 1617 1870 15.6 10.6 1691 28.11.2005 15 41 1598 1863 16.5 11.5 1671 28.11.2005 10 41 1521 1773 16.5 11.5 1590 28.11.2005 5 41 1487 1754 17.9 12.9 1554

average 1556 1809 16.2 11.2 1627 stdev 48 48 1.0 1.0 51

IX layer Lower cutting 28.11.2005 15 42 1472 1751 19.0 14.0 1536 28.11.2005 10 42 1478 1761 19.1 14.1 1543

28.11.2005 5 42 1511 1790 18.5 13.5 1577 Loadman + volumeter 2

1487 1767 19 14 1552 21 20 0.3 0.3 22

IX layer Upper cutting 28.11.2005 15 43 1630 1875 15.0 10.0 1705 28.11.2005 10 43 1517 1782 17.4 12.4 1585 Volymeter 1 28.11.2005 5 43 1497 1751 17.0 12.0 1563

average 1548 1803 16 11 1618 stdev 72 65 1.3 1.3 76

51 APPENDIX 6

The test results of water content tests (Ekokem - Palvelut Oy)

date

sample

wet weight

dry weight

water cont. %

notes

Morning of 10th of november, mass produced previous day 10.11. A 20.9720 18.7390 11.9% infrared heater

A 107.0 96.0 11.5% oven, 105oC A 107.4 96.0 11.9% micro wave B 20.5680 18.1620 13.2% infrared heater B 102.0 91.1 12.0% oven, 105oC B 124.3 111.2 11.8% micro wave C 20.3070 18.0690 12.4% infrared heater

C 101.3 90.7 11.7% oven, 105oC C 108.3 96.5 12.2% micro wave wet, sticky mass 130.0 114.4 13.6% micro wave

Test samples taken on the 11.11.2005

14.11. horizontal structure 1 187.4 168 11.5% oven, 105oC horizontal structure 2 134.9 121.6 10.9% oven, 105oC horizontal structure 3 132.1 117.4 12.5% oven, 105oC horizontal structure 4 155 138.7 11.8% oven, 105oC horizontal structure 5 167.9 149.5 12.3% oven, 105oC stack, 5 192.9 171.8 12.3% oven, 105oC stack, 7 223.1 199.6 11.8% oven, 105oC stack, 8 235.1 212.1 10.8% oven, 105oC stack, 9 214.6 192.6 11.4% oven, 105oC stack, 10 198.2 178.2 11.2% oven, 105oC slope 11 111.7 99.7 12.0% oven, 105oC slope 12 158.2 141.6 11.7% oven, 105oC slope 13 85.5 77.5 10.3% oven, 105oC slope 14 90.1 80.8 11.5% oven, 105oC slope 15 113.5 101.7 11.6% oven, 105oC

53 APPENDIX 7

The grain size distribution of the crushed rock sample (Ekokem - Palvelut Oy)

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.063 0.125 0.25 0.5 1 2 4 8 16 31.5 63

Grain size # mm

Pas

sing

-% crushed rock

55 APPENDIX 8

The mix data of the bentonite - crushed rock mixture (Ekokem - Palvelut Oy) date mix nr Crushed rock Bentonite Water water content% Remarks 09.11.2005 1 1060 512 125 14.3 09.11.2005 2 1068 509 125 14.5 lumpy, disapproved 09.11.2005

3 1104 512 122 dusty, water feed malfunction,

disapproved 09.11.2005 4 1602 714 164 14.9 lumpy, disapproved 09.11.2005 5 1675 785 154 14.0 09.11.2005 6 1065 585 100 12.4 09.11.2005 7 1071 516 100 14.1 09.11.2005 8 1076 510 91 12.1 09.11.2005 9 1062 509 95 12.6 09.11.2005 10 1079 509 94 12.2 09.11.2005 11 1104 509 91 12.5 09.11.2005 12 1060 512 90 11.5 09.11.2005 13 1063 512 91 09.11.2005 14 1072 516 90 09.11.2005 15 1190 514 90 09.11.2005 16 1088 515 91 09.11.2005 17 1150 514 86 09.11.2005 18 1006 513 89 09.11.2005 19 1129 511 89 09.11.2005 20 1061 511 88 09.11.2005 21 1166 511 89 09.11.2005 22 1055 512 90 09.11.2005 23 1066 512 89 09.11.2005 24 1071 514 90 09.11.2005 25 1173 512 90 09.11.2005 26 1043 512 88 09.11.2005 27 1160 512 90 09.11.2005 28 1151 510 90 09.11.2005 29 1101 515 92 09.11.2005 30 1097 510 92 09.11.2005 31 1102 512 89 09.11.2005 32 1075 514 90 09.11.2005 33 1157 513 90 09.11.2005 34 1090 511 89 09.11.2005 35 1091 512 91 09.11.2005 36 1114 514 91 09.11.2005 37 1056 511 92 09.11.2005 38 1067 516 91 09.11.2005 39 1045 512 92 10.11.2005 40 1099 506 91 10.11.2005 41 1100 509 90 10.11.2005 42 996 515 89 10.11.2005 43 1233 514 91 10.11.2005 44 1067 515 90 10.11.2005 45 1165 512 90 10.11.2005 46 1068 514 89 10.11.2005 47 1062 518 90

56 APPENDIX 8

date mix nr Crushed rock Bentonite Water water content% Remarks 10.11.2005 48 1047 511 89 10.11.2005 49 1104 513 84 10.11.2005 50 1062 508 90 10.11.2005 51 1065 513 90 10.11.2005 52 1055 516 89 10.11.2005 53 1063 516 89 10.11.2005 54 1065 514 87 10.11.2005 55 1067 509 88 10.11.2005 56 1074 516 90 10.11.2005 57 1070 515 89 10.11.2005 58 1127 515 90 10.11.2005 59 1114 513 90 10.11.2005 60 1063 513 89 10.11.2005 61 1081 512 90 10.11.2005 62 600 300 60

57 APPENDIX 9

The test results of LDWT tests (Dietmar Adam)

Compaction Equipment: LH700 Estimated layer thickness Dynamic vibratory plate ZFG-02

No. Date Time Layer Passes Before

compaction After

compactionDeflection single test

Deflection mean value s

E modulus Evd

[ mm ] [ mm ] [ mm ] [ mm ] [ MN/m² ] 10.11.2005 AC 0.268

1 10:02 0 0 250 200 0.115 0.139 161.9 0.033 10.11.2005 AC 0.012

2 10:07 0 0 250 200 0.024 0.019 1184.2 0.022 10.11.2005 0.337

3 10:46 1 2-3 250 200 0.34 0.341 66.0 0.345 10.11.2005 0.332

4 10:48 1 2-3 250 200 0.334 0.333 67.6 0.333 10.11.2005 0.343

5 11:36 1 4-6 250 200 0.247 0.275 81.8 0.236 10.11.2005 0.224

6 11:37 1 4-6 250 200 0.219 0.222 101.4 0.224 10.11.2005 0.318

7 11:52 1 6-9 250 200 0.251 0.270 83.3 0.242 10.11.2005 0.231

8 11:54 1 6-9 250 200 0.235 0.234 96.2 0.236 10.11.2005 12.18

9 13:03 2 1 250 200 7.319 8.321 2.7 5.465 10.11.2005 4.883

10 13:04 2 1 250 200 4.593 4.530 5.0 4.115 10.11.2005 3.571

11 13:05 2 1 250 200 3.258 3.259 6.9 2.949 10.11.2005 2.683

12 13:05 2 1 250 200 2.549 2.549 8.8 2.416 10.11.2005 0.782

13 13:19 2 2-3 250 200 0.468 0.559 40.3 0.428 10.11.2005 0.413

14 13:19 2 2-3 250 200 0.410 0.410 54.9 0.407

58 APPENDIX 9



compaction After



E modulus Evd

[ mm ] [ mm ] [ mm ] [ mm ] [ MN/m² ] 10.11.2005 0.413

15 13:29 2 4-6 250 200 0.410 0.410 61.1 0.407 10.11.2005 0.348

16 13:30 2 4-6 250 200 0.35 0.349 64.5 0.348 10.11.2005 1. point 0.636

17 14:12 2 6-9 250 200 0.459 0.511 44.0 0.439 10.11.2005 1. point 0.418

18 14:12 2 6-9 250 200 0.407 0.408 55.1 0.400 10.11.2005 2. point 0.318

19 14:14 2 6-9 250 200 0.276 0.289 77.9 0.273 10.11.2005 2. point 0.262

20 14:15 2 6-9 250 200 0.271 0.267 84.3 0.267 10.11.2005 too thick 0.716

21 14:46 3 2-3 400 300 0.392 0.493 45.6 0.371 10.11.2005 0.349

22 14:47 3 2-3 400 300 0.341 0.345 65.2 0.344 10.11.2005 0.506

23 14:59 3 4-6 400 300 0.292 0.360 62.5 0.282 10.11.2005 0.27

24 14:59 3 4-6 400 300 0.268 0.268 84.0 0.265 10.11.2005 0.331

25 15:15 3 6-9 400 300 0.287 0.302 74.5 0.288 10.11.2005 0.279

26 15:16 3 6-9 400 300 0.277 0.276 81.5 0.272 10.11.2005 0.419

27 15:37 4 2-3 250 200 0.382 0.388 58.0 0.363 10.11.2005 0.357

28 15:38 4 2-3 250 200 0.350 0.349 64.5 0.340

59 APPENDIX 9



compaction After



E modulus Evd

[ mm ] [ mm ] [ mm ] [ mm ] [ MN/m² ] 10.11.2005 0.459

29 15:45 4 4-6 250 200 0.357 0.385 58.4 0.338 10.11.2005 0.327

30 15:46 4 4-6 250 200 0.314 0.318 70.8 0.312 10.11.2005 0.396

31 15:47 4 4-6 250 200 0.341 0.362 62.2 0.349 10.11.2005 0.336

32 15:48 4 4-6 250 200 0.321 0.327 68.8 0.325 10.11.2005 0.432

33 16:00 4 6-9 250 200 0.305 0.343 65.6 0.291 10.11.2005 0.276

34 16:01 4 6-9 250 200 0.277 0.274 82.1 0.270 11.11.2005 0.511

35 09:13 4 6-9 250 200 0.355 0.402 56.0 0.339 11.11.2005 0.332

36 09:13 4 6-9 250 200 0.327 0.328 68.6 0.324 11.11.2005 0.575

37 09:15 4 6-9 250 200 0.389 0.445 50.6 0.370 11.11.2005 0.355

38 09:16 4 6-9 250 200 0.353 0.353 63.7 0.352 11.11.2005 0.357

39 09:18 4 6-9 250 200 0.335 0.339 66.4 0.325 11.11.2005 0.321

40 09:19 4 6-9 250 200 0.323 0.321 70.1 0.318 11.11.2005 0.397

45 10:03 4 6-9 250 200 0.369 0.375 60.0 0.359 11.11.2005 0.345

46 10:04 4 6-9 250 200 0.345 0.346 65.0 0.348 11.11.2005 0.366

47 10:05 4 6-9 250 200 0.301 0.319 70.5 0.291

60 APPENDIX 9



compaction After



E modulus Evd

[ mm ] [ mm ] [ mm ] [ mm ] [ MN/m² ] 11.11.2005 0.291

48 10:05 4 6-9 250 200 0.296 0.293 76.8 0.291 11.11.2005 0.745

49 10:07 4 6-9 250 200 0.561 0.622 36.2 0.559 11.11.2005 0.534

50 10:08 4 6-9 250 200 0.508 0.514 43.8 0.501

Layers removed 11.11.2005 0.287

51 11:26 0.29 0.288 78.1 0.288 11.11.2005 0.29

52 11:27 0.292 0.289 77.9 0.284

Compaction Equipment: roof compactor Dynamic vibratory plate ZFG-02

No. Date and Time Description of test spots

Deflection single test

Deflection mean

value s E modulus Evd

comments [ mm ] [ mm ] [ MN/m² ] 11.11.2005 3.634

41 09:41 point 1 2.691 2.940 7.7 2.495 11.11.2005 2.323

42 09:42 point 1 2.243 2.253 10.0 2.192 11.11.2005 1.005

43 09:53 point 2 0.449 0.620 36.3 0.407 11.11.2005 0.381

44 09:54 point 2 0.373 0.372 60.5 0.362

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To POSIVA OY

FIN-27160 Olkiluoto Brunn am Gebirge, April 2006 FINLAND Rev. 00

TECHNICAL REPORT

BACKFILLING AND CLOSURE OF THE DEEP REPOSITORY

ROOF COMPACTOR

LABORATORY AND FIELD TESTS

NUMERICAL SIMULATIONS

ASSOC.PROF. DIPL.-ING. DR.TECHN. DIETMAR ADAM AUTHORIZED CIVIL ENGINEERING CONSULTANT

FREE-LANCE ENGINEER

ASSOCIATE PROFESSOR AT THE INSTITUTE FOR SOIL MECHANICS AND GEOTECHNICAL ENGINEERING

VIENNA UNIVERSITY OF TECHNOLOGY

GEOTECHNIK ADAM ZT GmbH WIENER STRASSE 66-72/15/4 A-2345 BRUNN AM GEBIRGE

TEL +43-(0)2236/312244-11 FAX +43-(0)2236/312244-99

[email protected]

GEOTECHNIK ADAM

95 APPENDIX 17

GEOTECHNIK ADAM ZT GmbH Deep Repository – Roof Compactor

CONTENT

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

2. PROPERTIES OF BACKFILL MATERIAL .................................................................... 5

2.1. Results of preliminary basic investigations................................................................ 5

2.2. Characterisation of the backfill material .................................................................... 9

3. RIIHIMÄKI FIELD TESTS............................................................................................. 11

3.1. General ..................................................................................................................... 11

3.2. Determination of backfill material stiffness............................................................. 13

3.3. Observations of backfill material behaviour ............................................................ 15

3.4. Observations of roof compactor behaviour.............................................................. 22

4. NUMERICAL SIMULATIONS OF THE ROOF COMPACTOR.................................. 24

4.1. General ..................................................................................................................... 24

4.2. Modelling of the interaction system roof compactor and backfill material ............. 25

4.3. Preliminary investigations........................................................................................ 27

4.4. Motion and operation behaviour of the roof compactor on the slope ...................... 28

4.5. Compaction effect of the roof compactor on the slope ............................................ 34

4.6. Conclusions of the numerical simulations ............................................................... 40

5. FINAL REMARKS AND RECOMMENDATIONS....................................................... 41

APPENDIX

� Video clips of the numerical simulations

page

96 APPENDIX 17


1. INTRODUCTION

The joint SKB-POSIVA project “Backfill and Closure of the Deep Repository” deals with the

permanent repository of spent nuclear fuel in a tunnel system to be constructed in granite

formations some hundreds meter below sea level. The disposal tunnels have to be backfilled

with a suitable material in order to provide erosion stable and low permeable conditions. The

salt content of the seeping water has to be taken into account for the design of the backfill

concept. Six concepts (A to F) have been investigated, whereby the compaction of a mixture

of bentonite and crushed rock should be considered further on (concept A).

The basic dimensions for the Finnish disposal tunnel are: cross-section 14 m², floor width

3.5 m and maximum height 4.4 m.

The Swedish tunnels look similar, but they are twice as large: cross section 29 m², floor width

5.5 m and max height 5.5 m.

The compaction in the roof section of the tunnel has been revealed an unsolved problem. Due

to the narrow conditions in the remaining gussets no sufficient compaction degree could be

achieved there.

Consequently, the undersigned has been asked to give advice on compaction aspects

regarding the project, which will be discussed in this memorandum. During the planning

meeting on 06.04.2004 in Stockholm the participants of the meeting agreed that the

memorandum shall contain at least the following issues:

� Theory of compaction in general, effect of different compaction parameters (scope on

compaction of cohesive materials).

� If available reference to projects, where materials similar to the suggested backfill

material (with 30% bentonites and 10% other fines) has been compacted with the

suggested equipment. Density as a function of compaction time would be very interesting.

� Modelling the effect of different compaction equipment parameters with finite element

simulation. How to use the model to understand the physics of compaction? – Preliminary

investigation plan.

� Effect of different type of compactors on cohesive materials (especially equipment that

can be applied in tunnel conditions and for compaction of the roof section).

97 APPENDIX 17


� Pros and cons of suggested equipment & techniques: reversible plates, roof compactor

(excavator grab) and multipurpose compactors.

Furthermore, a sample of the mixture of bentonite and ballast (30/70) has been sent to the

Institute for Soil Mechanics and Geotechnical Engineering at the Vienna University of

Technology. Some basic tests have been performed so that the undersigned could attain an

insight into the material properties. Consequently, a more precise statement could be given on

the basis of these tests.

The issues have been discussed in a memorandum composed by the undersigned in June

2005. It served as a discussion basis for a further meeting, which took place on 02.09.2005 in

Stockholm. There it was agreed to investigate the so called roof compactor by numerical

simulations, which should be performed by the group of the undersigned. Therefore, field

tests were necessary to achieve material properties like soil stiffness, density, water content,

etc. and to get an insight about the compaction behaviour of the roof compactor both in the

inclined slope and on horizontal layers.

Field tests took place in Riihimäki (Finland) from 10 to 11.11.2006. Numerous tests were

performed on an inclined slope and on horizontal layers. The undersigned accommodated a

dynamic load plate test in form of a Light Falling Weight Device (LFWD) and determined the

dynamic deformation modulus, which is an important input parameter for the numerical

simulations.

Reports have been prepared on the results of the field tests by the parties who took part in the

Riihimäki field tests. The results are incorporated in the respective technical report but only

the issues concerning the roof compactor are discussed in detail.

In this report the properties of the backfill material are briefly described in the following

chapter based on the findings of the preliminary investigations performed by the undersigned

in spring 2005. The main focus is set to the properties influencing the compaction and motion

behaviour of the roof compactor.

98 APPENDIX 17


In the next chapter the main findings and observations of the Riihimäki field tests are

concluded. Especially the machine processing, and both the material behaviour and the

properties are discussed.

In the main chapter the results of the numerical simulations are presented. The modelling of

the roof compactor is discussed as well as the varied machine and soil parameters. Dynamic

elastic and quasi-static plastic investigations have been performed in order to simulate the

interaction system backfill material and roof compactor with sufficient accuracy. On the basis

of figures and video clips the findings are explained and demonstrated.

Finally, the results of the investigations are concluded and recommendations are given for the

further procedure.

2. PROPERTIES OF BACKFILL MATERIAL

2.1. Results of preliminary basic investigations

In spring 2005 some basic preliminary investigations have been performed at the Soil

Mechanics Laboratory at the Vienna University of Technology. The main focus was set on

the material behaviour with respect to compaction and characterising properties within

different conditions.

Following properties have been determined:

� natural water content

� density of solid particles (mixture)

� Atterberg limits (consistency limits)

� grain size distribution

� Proctor density and optimum water content

� moisture and dry density, and void ratio

� uniaxial compressive strength of compacted material and estimation of cohesion

� time-settlement behaviour

� swelling and subsidence behaviour of compacted samples exposed to different stresses in

the oedometric cell

� hydraulic conductivity of compacted samples in dependence of the void ratio

99 APPENDIX 17


The main conclusions from the memorandum of the undersigned (June 2005) are presented in

the following:

� The natural water content has been determined to wn = 11.8%. Thus it is in the range of

the optimum water content according to the Proctor test.

� The density of the solid particles of the mixture is �s = 2.70 g/cm³ and thus within the

expected range.

� The Atterberg limits yield high values (liquid limit wl = 109.5%, plasticity limit

wp = 33.0%, plasticity index Ip = 76.5%, consistency index Ic = 1.277, classification:

semi-solid to soild). Thus, the bentonite predominates within the fines.

� The grain size distribution is well graded (fractions: gravel 16%, sand 49%, silt 20%, clay

15%; maximum grain size: 6 mm) but not according to Fuller type grain size distribution.

Due to the high content of clay particles the degree of uniformity U could not be defined.

� The Proctor density has been determined to �s = 1.74 g/cm³ and thus, is lower than the

value determined in previous tests. The Proctor curve is more or less horizontal in the

range between 10 to 16%, thus a single value for the optimum water content could not be

found. The material seems to be ideally compactable in the range mentioned above.

� Before compaction the material is more or less non-cohesive and can be characterised as

non-cohesive coarse-grained to mix-grained material since the properties of the coarse

grains predominate.

After compaction the material is cohesive and can be characterised as cohesive mix-

grained material.

Consequently, for compaction process the material is classified to be semi-cohesive. In

the beginning of compaction it behaves more like a non-cohesive material and becomes

more and more cohesive progressively. This fact is important for the selection of the

compaction procedure and the equipment & technique!

As shown in Fig. 1 the material has been compacted in three layers. The compaction near

the impact zones is significantly better than in deeper zones. Two reasons are responsible

for this phenomenon: on the on hand the friction between the crushed rock grains is very

high (estimated friction angle > 35 to 40°), on the other hand the cohesion increases with

increasing compaction. In the lower zones of each layer the compaction effect decreases

significantly. It is important to note that the skin friction between the Proctor cylinder and

the material influences the compaction depth. In the unconfined field condition the

compaction depth can be assumed to be deeper.

100 APPENDIX 17


Fig. 1: Cylindrical sample compacted in three layers.

Fig. 2 shows the surface of a layer, which has been exposed to the falling weight of the

Proctor equipment. On the one hand a separation layer has been formed due to the

concentrated bentonite, which has been pumped up to the surface during compaction. On

the other hand the bentonite has changed colour, which indicates a chemical process

between the bentonite, the oxygen of the air and the iron of the falling weight. The shear

strength is decreased dramatically since the layers can be separated easily from each other

even in the dry condition.

Fig. 2: Separation surface exposed from direct impact of falling weight.

� The void ratio of compacted samples varies between n = 0.37 to 0.39. The distribution is

not uniform over the sample as indicated in Fig. 1.

101 APPENDIX 17


� The time-settlement behaviour under constant load revealed that the primary settlements

are immediately followed by the tertiary settlements (creeping behaviour). Practically no

secondary settlements (consolidation) could be observed.

� The uniaxial compressive strength of compacted samples varies between 200 and

345 kN/m². From that average cohesion can be derived between c = 20 to 60 kN/m². Two

kinds of failure modes have been observed: on the one hand brittle-like failure according

to Mohr-Coulomb-Theory and on the other hand failure due to bulging in the less

compacted zones of each layer. This proofs the strong dependency between the

compaction degree and the cohesion achieved only by compaction. The shear strength is

independent of the water content, even in the dry condition the cylindrical samples do not

disaggregate. The samples can be manually divided only along the separation planes

formed between the layers.

Fig. 3: Uniaxial compression test: brittle-like failure according to Mohr-Coulomb-Theory,

one-sided shear failure plane � 45+�/2 (left) and failure due to bulging in the less

compacted lower zone of the upper layer (right).

� Four oedometric tests (compression tests) have been performed in order to investigate the

swelling and subsidence behaviour due to the sudden water inflow (fresh water). The

samples were compacted to a compaction degree of about DPr = 87%. The samples were

initially loaded by 10, 50, 200 and 500 kN/m², thus, representing values beneath and

102 APPENDIX 17


above the formerly determined swelling pressure. All samples do comprise only relatively

low settlements in the phase of an unchanged the water content.

Sample 1 (10 kN/m²) shows a significant heave of about 8% due to the water impact.

During unloading swelling is not increasing.

Sample 2 (50 kN/m²) shows a less significant heave (about 1.5%) due to the water impact.

However, during unloading swelling is significantly increasing up to 6%.

Sample 3 (200 kN/m²) shows a significant sudden subsidence due to the water impact of

about 24% (!). During unloading the swelling process is much less than the subsidence

occurred due to the water impact. Thus, the final height is significantly smaller than the

original one.

Sample 4 (500 kN/m²) shows a significant sudden subsidence due to the water impact of

about 33% (!). During unloading the swelling process is much less than the subsidence

occurred due to the water impact. Thus, the final height is significantly smaller than the

original one.

It was observed that the material absorbed water very quickly, which affected the heave or

subsidence behaviour immediately.

� The hydraulic conductivity has been determined from 8E10-10 m/s (50 kN/m²) to 5E-

11 m/s (100 and 200 kN/m²).

2.2. Characterisation of the backfill material

Following characterisation for the compaction of the backfilling and closure of the deep

repository can be derived from the preliminary basic investigations performed at the Vienna

University of Technology:

� The material (mixture of bentonite (30%) & crushed granite (70%)) is suitable for

backfilling the deep repository, if sufficient compaction can be achieved.

� The grains interlock during compaction due to the rough surface of the crushed grains and

undergo cementation due to the bentonite content. Consequently, cohesion arises from

compaction and increases with decreasing void ratio. Thus, the layer thickness to be

compacted should be thin. Depending on the compaction equipment and the technology

maximum layer thicknesses between 15 and 25 cm are recommended.

� Significant separation surfaces are formed between the layers due to pumping bentonite

suspension up to the surface. An interlocking between the layers can be achieved by

103 APPENDIX 17


profiled drums (pad-foot drum, sheep foot drum, and polygonal drum). However, the

compaction depth is not significantly improved since the material is not kneadable (like

plastic clay etc.). Nevertheless, profiled (shaped) drums improve the gradeability of self-

propelled compaction equipment!

� An intensive dynamic compaction is more effective than the application of heavy dead

loads. The material comprising water content of less than 15% exhibits practically no

consolidation behaviour and after loading immediately creeping takes place.

� A sufficient dynamic compaction of horizontal layers and slightly inclined layers can be

easily achieved by conventional compaction equipment like vibratory rollers and

vibratory plate compactors.

� In zones close and adjacent to the (rough) tunnel walls an additional compaction by

vibratory tampers is recommended. Especially in cavities and rock niches the material

should be tamped in concentrated form. A high dynamic pressure should be aimed for a

sufficient contact.

� If a sudden water inflow occurs the material is susceptible to piping and hydraulic erosion

especially in the contact zone between the tunnel wall and the material. Slowly seeping

water reduces the danger of erosion because it (even salt water!) causes sudden swelling

in low stress condition, which increases the contact pressure.

� If high salt concentrations are expected, the material should be filled on the wet side of the

Proctor curve. Thus, enough fresh water is available for the beginning swelling process

immediately after compaction. Since the Proctor curve is more or less horizontal between

the water content from 10 to 16% the water content plays only a minor role for the

achievable compaction degree. However, it should be taken into consideration that the

increasing amount of water enhances the separation tendency of the material during

dynamic compaction!

� The roof area cannot be compacted sufficiently by conventional compaction equipment. In

general, compaction more or less perpendicular to the tunnel walls and/or the backfilled

area is to aim for. The loose non-cohesive material during placing is counterproductive

since no vertical slopes (without cohesion) are achievable. The local compaction could be

attained by small tampers, which are equipped with an inclined tamping plate similar to

the excavator grab or roof compactor. The material has to be placed and pre-compacted by

single impacts and afterwards intensively compacted by the specially shaped tamper. The

104 APPENDIX 17


tamper should be mounted on the boom of an excavator allowing axial-rotational

movements.

3. RIIHIMÄKI FIELD TESTS

3.1. General

The field tests are described in detail in a separate report prepared by Leena Korkiala-Tanttu

from VTT (Finnish Research Institute) and colleagues from other research institutions. In this

report those results are discussed, which are important for the understanding of the interaction

system backfill material and roof compactor.

In the scope of the field tests performed in Riihimäki from 10 to 11.11.2005 two test series

were carried out:

� Compaction of horizontal layers with a vibratory plate

� Compaction of inclined layers (1:1,5) with a roof compactor mounted on a carrier

Fig. 4: Vibratory plate Dynapac LH 700 (Photo: D. Adam).

105 APPENDIX 17


Fig. 5: Halltek’s roof compactor mounted on a carrier Gradall XL3300 (Photo: P. Keto).

Following equipments were applied:

� Vibratory plate Dynapac LH 700 for compacting the horizontal layers

� Halltek’s roof compactor mounted on a carrier Gradall XL3300 for compacting the

inclined layers

The material properties before, during and after compaction were determined by the following

field test methods:

� Dynamic load plate test in form of the Light Falling Weight Device (LFWD) to determine

the dynamic deformation modulus Evd;

� Loadman to determine the deflection modulus;

� Troxler nuclear gauge (2 different devices) to determine the wet density, dry density and

pore content (void ratio);

� Sand volumeter test equipment to determine wet density, dry density, and pore content

(void ratio).

106 APPENDIX 17


Fig. 6: Field test equipment: Troxler nuclear gauge, sand volumeter test equipment, Loadman,

Light Falling Weight Device (Photo: D. Adam).

Furthermore, the backfill material was undergone numerous laboratory tests after the field

tests presented in another report.

In a second test phase on 28.11.2005 further compaction equipments were tested on the

horizontal and inclined test sites. The BOMAG multipurpose compactor BMP 851 and the

BOMAG vibratory roller BW 211-D3 delivered satisfactory results according to the

conclusions of the Riihimäki test report. In this report these equipments are not considered

further on.

3.2. Determination of backfill material stiffness

The backfill material stiffness and its development during compaction is the most important

input parameter for numerical simulations since it influences motion and compaction

107 APPENDIX 17


behaviour of the compaction equipment significantly. The other elastic material parameters,

like wet density and Poisson’s ratio can be assumed to be constant.

The stiffness was derived from measurements performed with the dynamic load plate test in

form of the Light Falling Weight Device providing the dynamic deformation modulus Evd.

Fig. 7: Light Falling Weight Device (LFWD) for determining the material stiffness (Photo: D.

Adam).

The dynamic deformation modulus Evd was primarily determined in the scope of the first test

series on the horizontal layers. The subsoil consisted of an asphalt layer, thus, comprising a

high stiffness (“rigid subsoil”).

Four layers were filled, whereby the following thicknesses were applied respectively achieved

after compaction:

� Layer 1: 25 cm / 20 cm (before / after compaction)

� Layer 2: 25 cm / 20 cm

� Layer 3: 40 cm / 30 cm

� Layer 4: 25 cm / 20 cm

Before and after 2 – 3, 4 – 6 and 4 – 9 passes performed with the vibratory plate Dynapac

LH 700 the dynamic deformation modulus Evd was determined. In the following Figure 8 the

increase of Evd with additional passes is presented.

108 APPENDIX 17


1st LAYER

2nd LAYER MEAN V.

3rd LAYER

4th LAYER MEAN V.

LAYERS REMOVED

0

10

20

30

40

50

60

70

80

90

100

110

120

0 2 4 6

NUMBER OF PASSES

SUBGRADE1st LAYER2nd LAYER MEAN V.3rd LAYER4th LAYER MEAN V.2nd LAYER VALUES4th LAYER VALUESLAYERS REMOVED

Evd [MN/m²]

162 SUBGRADE

2-3 4-6 6-9

Test Site: Ekokem / Riihimäki - Finland Test Series No.1: Horizontal Layers Compaction equipment: Vibratory plate compactor Date: 10.11.-11.11.2005

PRELOADING

1st LAYER

2nd LAYER MEAN V.

3rd LAYER

4th LAYER MEAN V.

LAYERS REMOVED

0

10

20

30

40

50

60

70

80

90

100

110

120

0 2 4 6

NUMBER OF PASSES

SUBGRADE1st LAYER2nd LAYER MEAN V.3rd LAYER4th LAYER MEAN V.2nd LAYER VALUES4th LAYER VALUESLAYERS REMOVED

2-3 4-6 6-9

1184 SUBGRADE

Evd [MN/m²] Test Site: Ekokem / Riihimäki - Finland

Test Series No.1: Horizontal Layers Compaction equipment: Vibratory plate compactor Date: 10.11.-11.11.2005

MEASUREMENT1000

Fig. 8: Development of dynamic deformation modulus Evd determined with the Light Falling

Weight Device (LFWD) with additional passes on layers 1 to 4.

In general the final stiffness is achieved after 4 – 6 passes with the applied vibratory plate.

From these tests the range and the development of the elastic material stiffness could be

derived and has been used for the numerical simulations (see chapter 4). The dynamic

deformation modulus on the first layer is higher due to the rigid subgrade influencing the

measurement values.

3.3. Observations of backfill material behaviour

Compaction of the horizontal layers accomplished by the vibratory plate resulted in the

following observations:

109 APPENDIX 17


� The material (mixture of bentonite (30%) & crushed granite (70%)) could be compacted

sufficiently by the vibratory plate. The water content should be close to the optimum

water content otherwise the material sticks on the plate.

Fig. 9: Backfill material sticks on the plate, if water content is too high (Photo: D. Adam).

� The grains interlocked during compaction due to the rough surface of the crushed grains

and underwent cementation due to the bentonite content. Consequently, cohesion arised

from compaction and increased with decreasing void ratio. Thus, the layer thickness to be

compacted should be thin. Depending on the compaction equipment and the technology

maximum layer thicknesses between 15 and 25 cm (after compaction) are recommended.

More than 4 – 6 passes are not useful.

110 APPENDIX 17


Fig. 10: Already during the first compaction pass material changed from a non-cohesive

to a cohesive material and increased with additional 3 to 5 roller passes and remained

constantly then (Photo: D. Adam).

� Significant separation surfaces were formed between the layers due to pumping bentonite

suspension up to the surface. This effect could be clearly proven after removing the

layers. The material slid off between the layer surfaces. Overcompaction enhanced this

phenomenon and thus, should be avoided.

~0,8 m

Cutted surface

Fig. 11: Surface shape after removing the layers. Separation took place exactly along the

layer surfaces (Drawing: L. Korkiala-Tanttu).

111 APPENDIX 17


Fig. 12: After removing the material with an excavator the layers slid off exactly along the

layer surfaces (Photos: D. Adam).

� Some cracks perpendicular to the driving direction of the vibratory plate could be

observed during compaction, but these cracks were immediately sealed by the horizontal

component of the compaction force corresponding to the driving force of the vibratory

plate. This sealing effect enhanced the formation of the separation surface described

above.

Fig. 13: Sealed cracks could be observed after compaction of the material with a vibratory

plate (Photo: D. Adam).

� An intensive dynamic compaction was obviously more effective than the application of

heavy dead loads.

� A sufficient dynamic compaction of horizontal layers and slightly inclined layers could be

easily achieved by conventional compaction equipment like vibratory plate compactors

112 APPENDIX 17


choosing the right material parameters (water content) and layer thickness

accommodating to the machine parameters.

Compaction of the inclined layers accomplished by the roof compactor resulted in the

following observations:

� The compaction was performed from bottom to top. After the first pass the material

changed from non-cohesive to cohesive material behaviour below the compactor plate.

Fig. 14: During first compaction pass material changed from non-cohesive to cohesive

properties (Photo: D. Adam).

� Nevertheless, material trickled down on the slope due to the vibration of the slope caused

by the roof compactor. Thus, “fresh” material (uncompacted, loose, non-cohesive) formed

a thin layer over the compacted layer.

113 APPENDIX 17


Fig. 15: Loose material trickles from top to bottom along and behind the compactor due to

dynamic motion of the slope (Photo: D. Adam).

� During the second compaction pass the thin “fresh” material layer was compacted and

additional “fresh” material trickled down to the front of the curved plate of the roof

compactor. Thus, most vibration energy was absorbed by compaction of this thin layer

(thickness about 2 to 4 cm). No more effective compaction was possible then.

� During the third pass the formed separation layer between the original surface and the thin

layer emerged during the second compaction pass appeared by the formation of more or

less horizontal cracks. This phenomenon however was not only caused by the separation

layer but also by a local ground failure due to high pressure originating from the

resistance of the pre-compacted material especially at the edges of the contact area. Thus,

the shape of the curved plate of the roof compactor contributed as well.

114 APPENDIX 17


Fig. 16: More or less horizontal cracks were formed during the second compaction pass

(Photo: D. Adam).

� Due to the material transport from top to bottom the inclination was gradually reduced

from about 33° to about 28°. A constant slope inclination could not be kept. In two cuts

carried out after compaction of some layers the separation layer could be clearly seen.

Slope 1:1,5

2,0 m

Cuttings

Additional filling

33º28º

Fig. 17: Inclined test site. Slope inclination reduced gradually from layer to layer due to

material transport (Drawing: L. Korkiala-Tanttu).

115 APPENDIX 17


Fig. 18: In the cut the separation layers could be clearly seen (Photo: D. Adam).

3.4. Observations of roof compactor behaviour

The Halltek’s roof compactor was mounted on a self-propelled carrier Gradall XL3300 with

pneumatic tyres. Following observations were documented:

� The compaction was performed from bottom to top. Although the driver did an excellent

job the (static) contact pressure on the surface could not be kept constantly by manual

control even not during one compaction pass. Thus, the compaction effect was changed

without control.

Fig. 19: Roof compactor compacting material on the slope (Photos: D. Adam).

� Depending on the material stiffness and the actual contact pressure the compactor

obviously operated in different modes of operation. This was primarily indicated by the

116 APPENDIX 17


sound. A deep sound indicated the operating mode of the so called “double jump” (sub-

harmonics and thus lower frequencies occurred). A high sound indicated the so called

“continuous contact” and especially the “partial uplift” mode (harmonics of higher modes

and thus higher frequencies occurred) [listen (!) to video clips, e.g. Repository Backfill

2005_0044].

� When the contact pressure was obviously higher the dynamic force seemed to be too weak

for sufficient dynamic compaction.

� Energy transferred to the slope was primarily absorbed by the material trickling from top

to the front of the roof compactor. The large radius of the front part allowed the formation

of a wedge made of “fresh” material, which could not be compacted sufficiently.

Furthermore, the dynamic force was too low to “squeeze” this material wedge.

� Due to the shape of the curved plate of the roof compactor material could be squeezed out

in the front and the rear of the plate instead of compaction of the material.

� Furthermore, the shape of the curved plate in combination with the variable contact

pressure did not allow a sufficient “pre-stressing” of the material beneath the plate. Thus,

high pressure zones (probably near the surface) caused local ground failures (indicated by

the more or less horizontal cracks) of the pre-compacted material especially during the

third pass.

Fig. 20: Vibrating roof compactor caused local ground failure in the pre-compacted

material due to high pressure zones near the surface and the lack of pre-stressing of the

material (Photo: D. Adam).

117 APPENDIX 17


� In conclusion the compaction effect of the roof compactor strongly depended on the

(static) contact pressure. If it could be kept constantly, the compaction effect would be

sufficient. Nevertheless the trickling material due to the dynamic excitation has to be

taken into account because the “soft” wedge between the front of the curved plate and the

slope absorbed a considerable amount of the transferred energy.

4. NUMERICAL SIMULATIONS OF THE ROOF COMPACTOR

4.1. General

Numerical modelling has been used as a tool to study the motion behaviour and the

compaction effect of the roof compactor under variable conditions. Main influencing

parameters were identified and varied. Consequently, parametric studies could be performed.

The Halltek’s roof compactor is mounted on a carrier and controlled manually by an operator

using a hydraulic system. The following pictures show the roof compactor in detail.

Fig. 21: Halltek’s roof compactor: side view with curved plate and exciter engine and front

view showing both the vibrating part and the non-vibrating bearing arm (Photos: D. Adam).

118 APPENDIX 17


4.2. Modelling of the interaction system roof compactor and backfill material

Roof compactor and backfill material were modelled using the Finite Element Code

MSC.MARC.

The roof compactor is composed of a vibrating part and a non-vibrating bearing arm. They are

connected to each other by rubber isolators forming a spring-damper element between these

two parts. The vibration is produced by an eccentric mass rotating with constant speed and a

constant eccentricity. The vibratory plate is curved in one direction and composed of three

cylindrical segments each comprising a different radius.

In the following the main modelling data of the roof compactor are presented:

� Vibrating weight 293 kg

� Amplitude 2,6 mm

� Excitation frequency 43 Hz

� Eccentric mass 15,23 kg

� Eccentricity 0,0499 m

� Centrifugal force 55369 N

� (Static) contact pressure 0, 10, 20, 30, 40, 50 kN (variable)

Fig. 22: Main geometry of the roof compactor and grid of the modelled backfill material.

119 APPENDIX 17


The backfill material was modelled with sufficient accuracy by a linear elastic continuum

model. The contradiction that compaction is an irreversible, highly plastic behaviour is

obvious. However, it is not necessary to simulate the whole compaction process in one

calculation process but respective compaction states. Different states of compaction were

modelled with varying material parameters:

� elastic stiffness, geometric and material damping of the sub-soil and other elastic

parameters (Poisson’s ratio, density)

� actual elastic stiffness and material damping of the material to be compacted and other

elastic parameters (Poisson’s ratio, density) taking also into account possible pore water

pressures etc., representing the actual soil reaction due to the dynamic load

� geometry of sub-soil and layer thickness to be compacted

� inclination of the working platform

In the following the main modelling data of the roof compactor are presented:

� Dynamic elastic modulus 20, 40, 60 MN/m²

� Density 2000 kg/m³

� Poisson’s ratio 0,3

� Material damping variable, depending on material stiffness

� Slope inclination 1:1,5 (34°)

� Layering homogeneous material (constant material parameters)

The interaction system roof compactor and backfill material have to be modelled in a way that

only pressure can be transferred, tension between the compactor and the material is virtually

not possible. Furthermore, friction in the contact area has to be defined.

While both the compactor and the material to be compacted are assumed to be linear systems,

the interacting system is highly non-linear due to the contact problem. This non-linearity is

primarily responsible for many non-linear effects like the different operating modes, which

occur during compaction.

120 APPENDIX 17


4.3. Preliminary investigations

In the scope of preliminary simulations and considerations the different parameters of the

machine and the backfill material were varied in order to identify the parameters mainly

influencing the motion behaviour and compaction effect of the roof compactor. The

contribution of each parameter is discussed in the following:

Machine parameters:

In general machine parameters are tuned well. Thus, a stable operation is possible, if the

(static) contact pressure is chosen well. Depending on the (static) contact pressure the

dynamic force should be raised with increasing contact pressure. Details are given in the

following chapters and in the conclusions.

Geometry of the plate:

The shape of the plate should be comparable to typical vibratory plate compactors consisting

of an even plate in the centre and curvatures with small radius at the front and the rear of the

plate. Nevertheless, the plate cannot follow sufficiently the contour at the top end of the

tunnel. Details are given in the following chapters and in the conclusions.

(Static) contact pressure:

The (static) contact pressure is the most influential machine parameter. Thus, it was varied

from 0 to 50 kN in steps of 10 kN.

Dynamic elastic modulus of backfill material:

The dynamic modulus is the most influential backfill material parameter. It was derived from

dynamic deformation modulus determined at Riihimäki field tests. Three values, 20 MN/m²,

40 MN/m² and 60 MN/m², were used representing soft (pre-compaction), medium and stiff

(final compaction) material behaviour.

Density, Poisson’s ratio, and material damping:

Although these values change within the compaction states they can be kept constantly since

the variation in a realistic range influences the motion behaviour and the compaction effect

only to negligible degree.

121 APPENDIX 17


Slope inclination:

In practice the slope inclination is most influential on the compaction success since “fresh”

material trickles down the slope depending on the inclination. Furthermore, with increasing

inclination it is more and more difficult to keep the (static) contact pressure constantly. In the

scope of the simulations the slope inclination can be neglected because the material transport

does not occur.

Layering:

Field tests showed that the material can be assumed homogeneously. Thus, layering was not

taken into account in the scope of the simulations. Stiffness variation can be considered by

variable dynamic elastic modulus.

4.4. Motion and operation behaviour of the roof compactor on the slope

The basic study for a dynamic compaction tool comprises the determination of the motion

behaviour and the way of operation (operation mode). If the equipment is not tuned well, no

stable operation behaviour can be ensured.

Depending on the variation of the most influential (static) contact pressure and the material

stiffness representing different compaction states the roof compactor and backfill material

interaction system has been simulated.

In the first step the results are presented in form of contact force – plate displacement

relationships. The diagrams show the force – displacement relationship in the interface

between roof compactor and backfill material. Contact conditions can be analyzed as well as

operation modes.

In a second step the results are analyzed in the time domain. The contact forces are plotted

over time. Contact conditions, periodicity, operation modes, stability of the motion behaviour

and the loading characteristics can be analyzed.

Figures 23 and 24 clearly reveal that the (static) contact pressure is mainly responsible for the

functioning and the ways of operation of the roof compactor:

122 APPENDIX 17


� Zero contact pressure (0 kN) causes chaotic motion behaviour even at low stiffness and

thus, no periodic operation of the roof compactor is possible. The contact phases are short

compared to the uplift time spans. The roof compactor impacts the material surface

irregularly. The peak force does not show any reproducibility depending on the varied

parameters.

� With increasing but nevertheless low (static) contact pressure (around 10 kN) the roof

compactor turns into the stable operating mode double jump. The motion behaviour is

periodic but the signal repeats itself only every second, third, etc. excitation cycle.

Moreover, this operation mode is characterized by relatively long uplift phases compared

to contact time spans. Thus, the compaction is impact-like, whereby the impact forces

differ from each other. Taking into consideration the varying material stiffness the impact

forces increase with increasing stiffness as well. While the compaction can be

accomplished quite reliably in the state of low compaction (i.e. low stiffness) the overall

behaviour becomes more and more unfavourable with additional compaction passes

causing increasing stiffness.

� Medium (static) contact pressure (from 20 to 30 kN) improves the motion behaviour of

the roof compactor comprising the so called partial uplift mode. This mode is

characterized by a periodic loss of contact, whereby the periodicity is equal to that of

excitation. The dynamic contact forces increase significantly with increasing material

stiffness. This can be explained by the higher resistance and by the reduction of the

contact time span. The impact-like loading is at a maximum at this parameter

combination. High impact-like forces are unfavourable since the material stresses exceed

the shear strength resulting in local failures. Such surface-near local failures could be

observed in the scope of the Riihimäki field tests.

� Higher (static) contact pressure (around 40 kN) shows an unchanged motion behaviour

but the dynamic peak forces decrease with increasing contact pressure causing a higher

pre-stressing rate. Moreover, the contact periods grow and thus, the impacts weaken. The

compaction behaviour is improved because the stresses are decreased and consequently

also the potential of failure. Nevertheless, the contact force increases disproportionate

with soil stiffness.

123 APPENDIX 17


� At high (static) contact pressure (around 50 kN) the motion behaviour changes and the

operation mode continuous contact occurs, which is defined by no loss of contact during

compaction. Thus, pre-stressing is so high at this stage that the excitation energy is

continuously transferred to the material to be compacted. The maximum dynamic contact

forces decrease in comparison with lower contact pressures (!) and are almost independent

of the material stiffness. If the material stiffness is increased, the roof compactor operates

in the partial uplift mode again. In this case the maximum dynamic force increases as well

due to the impact-like loading. Consequently, more energy is transferred to the material

while the maximum dynamic contact forces are lower resulting in the conclusion that the

compaction effect is optimized and the compaction depth effect is synchronously

improved.

124 APPENDIX 17


Dynamic contact force – plate displacement relationship

(Static) contact force 0 (Static) contact force 10 kN

(Static) contact force 20 kN (Static) contact force 30 kN


Fig. 23: Dynamic contact force – plate displacement relationship; (static) contact forces (0,

10 kN/m², 20 kN/m², 30 kN/m², 40 kN/m², 50 kN/m²) and soil stiffness E (blue: 20 MN/m²,

red: 40 MN/m², yellow: 60 MN/m²) are varied.

static force

static force

static force static force

static force

125 APPENDIX 17


Contact force over time




Fig. 24: Dynamic contact force over time; (static) contact forces (0, 10 kN/m², 20 kN/m²,

30 kN/m², 40 kN/m², 50 kN/m²) and soil stiffness E (blue: 20 MN/m², red: 40 MN/m², yellow:

60 MN/m²) are varied.

“chaos” “double jump”

“partial uplift” “partial uplift”

“partial uplift” “continuous contact”

126 APPENDIX 17


Numerical simulations revealed the existence of four operation modes for the roof compactor:

� Continuous contact

� Partial uplift

� Double jump

� Chaotic motion

The occurrence is mainly influenced by the (static) contact pressure and to a minor degree by

the material stiffness as well. Definitions and influence parameters are given in Table 1

presented below. Best compaction effect can be expected at relatively high (static) contact

pressures so that the plate operates in the modes continuous contact or partial uplift with long

contact periods and only very short uplift time segments. Thus, the impact-like loading is

minimized.

roofcompactor

plate motion

Interaction plate-material

operating condition soil contact force compaction

effectsoil

stiffnesscontact

pressure

continuous contact

CONT. CONTACT very good low high

PARTIAL UPLIFT good

DOUBLEJUMP poor

chaotic non-periodic loss of contact

CHAOTIC MOTION no high low

OPERATION MODES OF ROOF COMPACTOR

perio

dic

perio

dic

loss

of

cont

act

Table 1: Operation modes of a roof compactor detected by the numerical simulations and

already suspected during the Riihimäki field tests.

127 APPENDIX 17


4.5. Compaction effect of the roof compactor on the slope

The compaction effect of the roof compactor has been analyzed by means of the (elastic)

stress distribution in the backfill material due to dynamic excitation. Numerical simulations

have been performed by varying the (static) contact force and the stiffness of the backfill

material.

In a first step the results are evaluated by means of the stress distribution at maximum plate

deflection. Due to the dynamic nature of the interaction system, i.e. the geometric damping

(additional to the material damping), inertia forces, and wave propagation maximum

deflection and maximum stresses do not occur at the same time. The sequences of stresses

arising during two cycles of excitation are demonstrated on the video clips, which are

attached in the appendix of this report.

In a second step the maximum stresses on the surface of the backfill material are evaluated

depending on the (static) contact force exemplary for E = 60 MN/m².

The stress distribution depends strongly on the machine and material parameters, the

geometry of the plate and the (static) contact pressure. Figures 25, 26, 27 and 28 yield:

� Although the plate is curved the maximum stresses occur at the front and the rear of the

contact area. The potential of local failure is significantly higher at these edges compared

to the rest of the contact zone. On the one hand material can be squeezed out within the

“wedges” between plate and material, on the other hand local ground failure indicated by

horizontal cracks on the surface can be caused. This phenomenon was effectively

observed during the Riihimäki field tests!

� In the case of zero and low (static) pressures (0 to 10 kN) the increase of stresses in the

backfill material is limited to a low depth. The missing pre-stress does not allow a

significant compaction effect, which occur separately below the front and the rear edge of

the contact area.

� Medium (static) contact forces (20 to 30 kN) improve the overall compaction effect in

general but nevertheless the depth effect is low further on. The stress bubbles at the edges

128 APPENDIX 17


of the plate grow together and consequently, the compaction process takes place below

the whole contact area. In this state the maximum stresses beneath the surface occur due

to the impact-like loading in the partial uplift operation mode. This effect causes local

failure and material squeezing at the edges of the plate as well.

� The stress bubble is significantly increased only in the case of a moderately high to high

(static) contact force (40 to 50 kN). The energy propagates deep into the material during

continuous contact and does not “deflagrate” in the surface-near zones while

disadvantageous operation modes like partial uplift (with long uplift phases), double jump

and chaotic motion occur. Comparing the stress bubbles for soil stiffness E = 40 MN/m²

and E = 60 MN/m² at maximum (static) contact force of 50 kN the figures clearly show

that the depth effect is lower at higher stiffness. This phenomenon is explained by the fact

that the operation mode changes from continuous contact to partial uplift again due to the

higher deflection resistance of the stiffer material.

� Figure 28 clearly reveals that the maximum dynamic stresses do not occur at maximum

static contact forces. Low (static) contact pressures are unfavourable due to the

disadvantageous operation modes comprising long uplift phases while medium (static)

contact pressures produce high maximum stresses especially at the edges of the curved

plate. Resulting local failure and squeezing effects have already been mentioned. At high

(static) pressures the maximum stresses are reduced especially at the edges of the plate

and the stresses are better distributed causing significantly improved compaction and

depth effects.

129 APPENDIX 17





Fig. 25: Stresses in backfill material (E = 20 MN/m²); (static) contact forces (0, 10 kN/m²,

20 kN/m², 30 kN/m², 40 kN/m², 50 kN/m²) are varied.

130 APPENDIX 17







131 APPENDIX 17







132 APPENDIX 17


(Static) contact force 0 � ca. 6 bar (Static) contact force 10 kN � ca. 7,5 bar

(Static) contact force 20 kN � ca. 10 bar (Static) contact force 30 kN � ca. 10 bar

(Static) contact force 40 kN � ca. 9 bar (Static) contact force 50 kN � ca. 8,5 bar

Fig. 28: Maximum stresses at the surface of the backfill material (E = 60 MN/m²).

133 APPENDIX 17


4.6. Conclusions of the numerical simulations

The main findings of the numerical simulations can be concluded as follows:

� The numerical calculation results clearly show that a constant (static) contact pressure

applied to the roof compactor plate is necessary for a compaction process delivering a

continuous and reliable compaction effect.

� Compaction without (static) contact pressure, i.e. without pre-stressing is not reliable and

effective.

� The roof compactor works in different modes of operation. Four typical operation modes

were detected by the numerical simulations:

o Continuous contact

o Partial uplift

o Double jump

o Chaotic motion

� The mode of operation strongly depends on the (static) contact pressure. The higher the

contact pressure the more tends the plate to a stable mode, i.e. partial uplift and

continuous contact. The stiffness of the backfill material contributes as well but to a minor

degree.

� The depth effect strongly depends on the (static) contact pressure. The higher the contact

pressure the higher is the compaction effect in deeper zones.

� Depending on the (static) contact pressure following phenomena occur:

o For low (static) contact pressure the operation mode of double jump even

occurs for low material stiffness. Energy applied “deflagrates” at the surface.

o Medium (static) contact pressure causes high material reaction forces due to

the periodic loss of contact of the roof compactor plate since the periodic

contact loss produces an impact-like compaction. This effect is increased at a

higher material stiffness.

o At high (static) contact pressure the roof compactor plate remains longer in the

advantageous contact mode. Lower forces and stresses occur in the material.

The compaction energy is better distributed and propagates also to deeper

zones. The material reaction forces and stresses decrease due to the applied

periodic, sinusoidal compaction force; impact-like loading is thus prevented.

134 APPENDIX 17


Consequently, the overall compaction effect can be optimized by increasing

the (static) contact pressure.

� The motion behaviour of the roof compactor is not strongly influenced by the inclination

of the slope. From the practical point the dynamically caused trickling of the material has

to be taken into account since it affects the compaction effect. The steeper the slope the

more material trickles down to the front of the plate and aside.

� The shape of the plate influences the compaction effect as well. The relatively large radius

at the front and at the rear of the plate forms a wedge, where material can be squeezed out

during compaction procedure. More effective seems to be a plate, which is even in the

centre part and possesses curvatures with small radius at the front and the rear of the plate

comparable to a typical vibratory plate compactor. Thus, the squeeze effect can be

reduced to a minimum. Nevertheless, the plate cannot follow sufficiently the contour at

the top end of the tunnel.

� In general the plate is designed in a way that it can compact in stable modes, if the (static)

contact pressure can be controlled and kept constantly in a respective range. Currently,

this cannot be guaranteed since the chassis of the carrier and the extension arm do not

allow constant pressure conditions. Furthermore, the pressure is controlled manually by

the operator. A pressure control by pressure pads and/or an automatic control mechanism

should be implemented in the system. Moreover, for higher (static) contact pressures the

dynamic excitation force (centrifugal force) could be enlarged in order to improve the

compaction effect at favourable high (static) contact pressure.

5. FINAL REMARKS AND RECOMMENDATIONS

In conclusion the roof compactor should be modified to be included into further

considerations. Primarily the constant (static) contact pressure must be increased and

controlled manually or automatically. Otherwise no reliable compaction effect can be

achieved by the roof compactor.

For that a stable carrier has to be provided so that the motion of the cantilever arm can be

controlled exactly. The control mechanism of the constant (static) contact pressure can be

based on a pressure measurement between the vibrating part and the non-vibrating bearing

135 APPENDIX 17


arm. Continuously the mean value of the actual contact pressure has to be determined,

transferred and displayed to the operator on-line. On the one hand the operator can control the

pressure manually (that needs experience and demands skill!), on the other hand an automatic

control system can manage the pressure (that needs some development expenditure!).

Moreover, when the shape of the plate is optimized, the dynamic force is increased, and the

inclination of the slope is reduced it is expected that sufficient compaction can be achieved.

Nevertheless, in the most upper section of the tunnel a special solution has to be developed. A

vertical plate, which is shaped according to the tunnel roof curvature, could be used in a way

that it prevents the trickling of the material when the dynamic compaction force is applied. It

is recommended to consider such a solution in the forthcoming project phase in addition to

the hitherto compaction considerations.

DIPL.-ING. DR.TECHN. DIETMAR ADAM INGENIEURKONSULENT FÜR BAUINGENIEURWESEN WIENER STR. 66-72/15/4 A-2345 BRUNN AM GEBIRGE

136 APPENDIX 17

packfill - development of in situ compactionand the effect of the compactor has been studied. based...

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