Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones Based on ONKALO Tunnel Mapping, m Tunnel Chainage

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1 Working Report Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones Based on ONKALO Tunnel Mapping, m Tunnel Chainage Harri Kuula September 2010 POSIVA OY Olkiluoto FI EURAJOKI, FINLAND Tel Fax

2 Working Report Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones Based on ONKALO Tunnel Mapping, m Tunnel Chainage Harri Kuula WSP Finland Oy September 2010 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.

3 Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones Based on ONKALO Tunnel Mapping, m Tunnel Chainage ABSTRACT In this report, the rock mechanics parameters of fractures and brittle deformation zones in the vicinity of the ONKALO area have been estimated, the analysed data being from the ONKALO tunnel over the chainage range m. Some analysis has also been made based on core logging data from the drillholes OL-KR1 OL-KR40. At this stage, the main objective of the work is to obtain preliminary parameters for the rock mechanics simulations and the rock mechanics design. In this report, the rock mechanics parameters of the fractures are mainly associated with the rock engineering classification quality index, Q, which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. The fracture wall compressive strength (JCS) has been systematically estimated for the chainage range m using Schmidt hammer tests. So far, only a few laboratory direct shear tests have been conducted on fracture samples. Estimation of the mechanics properties of the brittle deformation zones (BDZ) is based on the mapped Q value, which is transformed to the GSI value in order to estimate strength and deformability properties. A component of the mapped Q values is from the ONKALO and another component is from the drill cores. The intact rock strength of the brittle deformation zones has been evaluated using Schmidt hammer tests. Keywords: Nuclear waste disposal, Olkiluoto, rock mechanics, fracture, brittle deformation zones, mechanical properties, Q-mapping.

4 ONKALOn ajotunnelin paaluväliltä m määritetyt rakojen ja rikkonaisuusvyöhykkeiden kalliomekaaniset ominaisuudet TIIVISTELMÄ Tässä raportissa on esitetty kallion rakojen ja hauraiden deformaatiovyöhykkeiden kalliomekaanisten parametrien määritys. Lähtöaineistona on käytetty ONKALOn ajotunnelin paaluvälin m kalliolaatukartoitusta. Kairareikien OL-KR1 OL- KR40 kartoitusaineistoa on käytetty jossain määrin. Työn tarkoituksena on ollut saada määritettyä alustavat laskentaparametrit kalliomekaanisia simulointeja ja suunnittelua varten. Myöhemmin, kun ONKALOn ajotunnelista saadaan lisää kartoitusaineistoa, tullaan parametrien arvot päivittämään. Raportissa esitettyjen kalliorakojen parametrien määritys perustuu Q-luokituksella määritettyyn kalliolaatuun. Rakopintojen kitkakulma on määritetty luokituksen Jr ja Ja lukujen avulla. Rakopinnan puristuslujuus (JCS) on määritetty systemaattisesti Schmidtin vasarakokeiden avulla paaluvälillä m. Rakopintojen laboratoriomittakaavaisia leikkauslujuusmäärityksiä on tehty toistaiseksi vain muutamia. Hauraiden deformaatiovyöhykkeiden mekaaniset ominaisuudet on määritetty myös Q- luokituksen avulla. Q-luvun avulla on laskettu GSI-luku, josta on määritetty vyöhykkeen lujuus- ja muodonmuutosominaisuudet. Vyöhykkeessä olevan kiinteän kiven lujuus on määritetty Schmidtin vasarakokeiden avulla. Avainsanat: Ydinjätteen loppusijoitus, Olkiluoto, kalliomekaniikka, hauras deformaatiovyöhyke, rakoilu, mekaaniset ominaisuudet, Q-luokitus.

5 1 TABLE OF CONTENTS ABSTRACT TIIVISTELMÄ 1 INTRODUCTION FRACTURES Geometrical properties of fractures Major fracture sets from tunnel mapping data Major fracture sets from drillhole data Number of fracture sets, Jn value Fracture intensity, RQD value Fracture length and end type Mechanical properties of fractures Fracture surface parameters, Jr and Ja values Fracture friction angle Fracture undulation Fracture wall compressive strength Fracture laboratory shear strength Fracture properties from Barton-Bandis failure criterion BRITTLE DEFORMATION ZONES Location of brittle deformation zone intersections Estimation of strength and deformability properties Strength of the intact rock Strength and deformability properties of brittle deformation zones CONCLUSIONS RECOMMENDATIONS REFERENCES APPENDICES... 41

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7 3 1 INTRODUCTION To characterize the Olkiluoto rock mass for the purpose of hosting a radioactive waste repository, it is necessary to have a rock mechanics model in order to be able to predict the consequences of various repository design options, including the repository depth and deposition tunnel orientations. If the rock stresses are too high, due to the repository being located at too great a depth, damage or even spalling can occur in the deposition tunnels and deposition holes. If the tunnels intersect the fracture zones or are situated close to such zones, heavier rock support is required for the tunnels. If there are too many fractures forming rock blocks, there can be block fallout from the tunnel roof. The extent to which these problems might occur is a function of the stress state, the intact rock and fracture/fracture zone properties, and the location and orientation of the excavations. In this report, the rock mechanics parameters of fractures and brittle deformation zones in the vicinity of the ONKALO area have been estimated. The term fracture refers to a discontinuity in the rock mass which can have been caused by tension or shear stress. The brittle deformation zones are the major zones of fracturing characterised by a large geometrical extent and much greater width than in individual fractures. The results are used in various rock mechanical analyses; like key block analyses for rock support design, to estimate excavation response in discontinuous rock mass, repository scale thermo-mechanical analyses and in large scale stress-geology interaction analyses. The results are used in various rock mechanical analyses; like key block analyses for rock support design, to estimate excavation response in discontinuous rock mass, repository scale thermo-mechanical analyses and in large scale stress-geology interaction analyses. According to Hudson et al. (2008), there are six different methods to estimate the mechanical properties of brittle deformation zones. One of these, which is used in this report, is based on rock mass classification. Other methods involve direct and indirect measurements, analytical formulae based on knowing properties of individual fracture components, numerical modelling and back analysis. Analysed data are from the ONKALO tunnel from chainage m. Some analysis has also been made based on core logging data from the drillholes OL-KR1 OL- KR40. At this stage, the main target of the work is to obtain preliminary parameters for rock mechanics simulations and rock mechanics design. In this report, the rock mechanics parameters of the fractures are mainly associated with the Rock Tunnelling Quality index, Q (Barton et al. 1974) including RQD value, Jn, Jr and Ja number. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. The fracture wall compressive strength (JCS) has been systematically mapped for the chainage range m using the Schmidt hammer tests. So far, only a few laboratory direct shear tests have been conducted on fracture samples. Estimation of the mechanical properties of the brittle deformation zones is based on the mapped Q value which is transformed to the GSI value in order to estimate strength and

8 4 deformability properties. The intact rock strength of the brittle deformation zones has been evaluated with Schmidt hammer tests and some point load tests have also been made.

9 5 2 FRACTURES 2.1 Geometrical properties of fractures The fracture data in this report are compiled from tunnel mapping results.in this context, the geometrical properties are defined via the orientation and density of fractures Major fracture sets from tunnel mapping data For this report, fracture data from the tunnel are available from chainage m, corresponding to a depth range of m. Fracture mapping data from the ONKALO area drillholes and tunnel pilot holes are also available. The best data are the tunnel mapping data because they include fracture length and waviness values, plus the fact that the fracture surfaces have not been affected by drilling. For the rock mechanics interpretation, all tunnel mapping has been processed in a manner, which is described in the evaluation report of the tunnel mapping (Engström & Kemppainen 2008). At the beginning of the processing, all fracture data from each mapping section are taken into account and in the processing itself the following rules have been used: All fractures, which have a length less than 1 m are excluded Fractures which terminate in intact rock are excluded. This procedure is going to be change because it has posed problems in long fractures. The long fractures terminating intact rock can not easily form a block, but they often have other fractures adjoining them and, can therefore, cause rock bursting and spalling. (Engström & Kemppainen 2008) After this processing stage, the fracture sets are defined from the non-excluded data. All rock mechanics parameters are calculated for these sets. This procedure differs from the geological DFN approach (Posiva 2009) in which all recorded observations are used in defining the fracture sets. The analysis of the major fracture sets is normally carried out for each 5 m long tunnel section. If the number of accepted fractures is too low to allow an interpretation of the major fracture sets, then the neighbouring five metre sections are incorporated. This effect to the definition of major sets orientation, not to other parameters. From the ONKALO tunnel mapping data, four major fracture sets have been interpreted for the first 2400 m chainage (Engström & Kemppainen 2008). Dip Dip Direction Fracture set Fracture set Fracture set Fracture set

10 6 The dominant fracture set (Set 1) is almost horizontal, dipping to the NE. The second fracture set is nearly vertical, striking in a N-S orientation. The third fracture set is also sub-vertical and perpendicular to the second set. The fourth set is parallel with the foliation, dipping around 32º to the SE (Figure 2-1). Figure 2-1. Fracture pole concentration contours for all mapped tunnel fractures and interpreted set windows (lower hemisphere plot). from Engström & Kemppainen The number of estimates of the main fracture sets from chainage 0 to 2440 m is 659 and the interpreted fracture set windows have been enlarged (Figure 2-2) to obtain a better adjustment of the previously presented fracture set directions. A) B) Figure 2-2. Fracture pole concentration contours from the main fractures sets: A) fracture set windows for set data. B) enlarged fracture set windows for set data.

11 7 In the first 250 m, the horizontal set (08 /065 ) is common. It is also present in the deeper parts of the tunnel, but more sparsely. The second fracture set (89 /081 ) exists almost regularly along the whole tunnel length. The third fracture set (85 /359 ) is found more rarely. The fourth fracture set (32 /135 ), which is parallel to the foliation, is dominant from 0 to 1100 m chainage; after that, it is less frequently observed (Figure 2-3, Figure 2-4, Figure 2-5). Figure 2-3. Main fracture directions for the ONKALO chainage m. Figure 2-4. Main fracture directions for the ONKALO chainage m.

12 8 Figure 2-5. Main fracture directions for the ONKALO chainage m. The considerable variation in fracture set orientations is typical for the ONKALO area, the maximum set concentrations being only 3 % to 6 %. All fracture sets can be found in the migmatites (VGN, DGN and SGN) and igneous rock (PGR, KFP). In the homogenous gneiss group, fracture set 3 is not observed in the TGG (Figure 2-6). Note that over 80 % of the observed fractures don t belong to defined major fracture sets.

13 9 100 % 90 % 80 % 70 % 60 % 50 % 40 % Set 1 Set 2 Set 3 Set 4 Others 30 % 20 % 10 % 0 % VGN DGN SGN MGN TGG MFGN QGN PGR KFP n = n = 2559 n = 303 n = 4917 n = 115 n = 113 n = 3646 n = 2178 n = 276 Rock type Figure 2-6. Comparison of different fracture sets within the different rock types. Migmatites: VGN = Veined gneisses, DGN = Diatexitic gneisses, SGN = Stromatic gneisses Homogeneous gneiss: MGN = Mica gneisses, TGG = Tonalitic granodiorites, MFGN = Mafic gneisses, QGN = Quartzitic gneisses, Igneous rocks: PGR = Pegmatite granite, KFP = K-feldspar-porphyritic rock Major fracture sets from drillhole data For comparison, drillhole data from vicinity of the ONKALO tunnel area were also analysed (Figure 2-7). In the drillhole data, gently-dipping fractures are most common because of the bias of data due to the orientation of the drillholes. Both vertical fracture sets can be found in some drillholes. No correlation between fracture orientation and depth can be found, nor any correlation between drillhole location and fracture orientation. Examples of two sets of drillhole fracture data are shown in Figures 2-8 and 2-9. Fracture data from other drillholes (hatched area in Figure 2-7 ) are presented in the Appendices. Note that the trend of drillhole OL-KR28 is 330, which biases the data so that vertical fractures, striking in a N-S orientation, cannot generally be intersected.

14 10 Figure 2-7. Location of drillholes in the vicinity of the ONKALO tunnel area. a) drillhole depth m b) drillhole depth m c) drillhole depth m Figure 2-8. Fracture pole concentration contours for drillhole OL-KR4, lower hemisphere projection.

15 11 a) drillhole depth m b) drillhole depth m c) drillhole depth m Figure 2-9. Fracture pole concentration contours for drillhole OL-KR28, lower hemisphere projection Number of fracture sets, Jn value The Jn value specifies the number of fracture sets. A set is defined as parallel fractures occurring systematically with a characteristic spacing. Random fractures are fractures that do not occur systematically and do not generally take part in the formation of blocks. When the fracture spacing is several metres, systematically occurring fractures may also be considered as random if they are rather unimportant for the stability (Løset 1997). The number of fracture sets varies with tunnel chainage. Over the first 300 m, the Jn median is 6, which means that systematic or occasional rock blocks can be formed. In terms of block fallout, the minimum number of faces that a block can have is four (a tetrahedral block); the tunnel periphery can form one face, so that a minimum of three fracture sets is then required for a rock block to be formed, indicated by the red lines in Figure From chainage 300 m to about 1200 m, the Jn median is 3 and, after chainage 1200 m, the Jn median drops to 1 (Figure 2-10).

16 Jn = 9, three joint sets Jn = 6, two joint sets + random Jn = 4, two joint sets Jn = 2, one joint set Jn = 0.5-1, massive no or few joints 8 Jn value Onkalo Chainage Jn = 9, three joint sets Jn = 6, two joint sets + random Jn = 4, two joint sets Jn = 2, one joint set Jn = 0.5-1, massive no or few joints 8 Jn value Onkalo Chainage Figure Histogram of logged Jn values in the ONKALO tunnel. Block fall-out due to fractures can only occur when three or more fracture sets are present, i.e. above the red line in the histogram.

17 Fracture intensity, RQD value The Rock Quality Designation index (RQD) was developed by Deere (Deere et al. 1967) to provide a quantitative estimate of rock mass quality from drill core logs. RQD is defined as the percentage of intact core pieces longer than 100 mm in the total length of core. When no core is available but discontinuity traces are visible in surface exposures or exploration adits, the RQD may be estimated from the number of discontinuities per unit volume (Palmström 1982). The suggested relationship for clayfree rock masses is: RQD = Jv (1) where Jv is the sum of the number of joints per unit length for all joint (discontinuity) sets known as the volumetric joint count. The ONKALO tunnel RQD values have been estimated by 1 m long scanlines for each 5 m long tunnel section. For this report, RQD data are available up to chainage 2925 m. The mean RQD value in the ONKALO tunnel from chainage 0 to 2925 m is 97 %. From chainage 1200 m, the fracture intensity starts to decrease and the mean RQD value in the chainage range m is 99.8 % compared to the mean value in the chainage range m of 94 % (Figure 2-11). The minimum RQD value is 10 % at chainage 2327 m. The width of this zone is 0.2 m. This zone intersection (ONK-BFI ) is compiled of core with TCF fracture and small damage zone on both sides of the core. A horizontal fracture set crosscut through the zone intersection. The intersection is crosscutting another zone intersection (ONK-BFI ) in the roof. At chainage 2483 m, the RQD value is 30 % and the width of the zone is 0.3 m. This is the place where brittle deformation zone OL-BFZ100 intersects ONKALO tunnel. Same zone intersects tunnel also in the chainage m, where RQD value is about 70 %. A significant width of high fracture intensity area can be found from chainage 285 m to 295 m where the RQD value is 50 %. Chainage contains a BFI (Brittle Fault zone Intresection), which comprises several moderately dipping filled fractures. Another low value section, 55 % < RQD < 65 %, exists from chainage 260 m to 274 m, where the Brittle Fault zone Intersection (ONK-BFI ) is composed of a single subhorizontal fracture. This fracture has a trace length of approximately 50 m and it was visible in both walls. The clay-filled fracture is surrounded by a 40 cm wide zone of soft and weathered rock in the latter part (chainage ) of the intersection. The Brittle Fault zone Intersection ONK-BFI in the chainage is composed of a single slickenside fracture with a visible trace length of ca 70 m, reaching the tunnel roof at chainage 513. In places this fracture branches to several fractures with the same directions as the main

18 RQD value RQD value RQD value (30 period moving average) Tunnel chainage (m) Figure Logged RQD values for the ONKALO chainage range m. The drillhole RQD data were recorded for 1 m long sections. The median values for the depth ranges m and were calculated for the deep drillholes (drillholes which extend at least to the level z = -250). The average RQD values of these median values are 96.6 % between m and 99 % between m (Figure 2-12) RQD value OL-KR1 OL-KR2 OL-KR3 z = m z = -120 m.-250 m OL-KR4 OL-KR5 OL-KR6 OL-KR7 OL-KR8 OL-KR9 OL-KR10 OL-KR11 OL-KR12 OL-KR13 OL-KR14 OL-KR15 OL-KR19 OL-KR20 OL-KR22 OL-KR23 OL-KR24 OL-KR25 OL-KR27 OL-KR28 OL-KR29 OL-KR33 OL-KR37 OL-KR38 OL-KR39 OL-KR40 Figure Median values of the RQD (% values) recorded over one metre sections for different drillholes.

19 15 The first quotient (RQD/Jn) of the rock tunnelling quality index (Q = RQD/Jn Jr/Ja Jw/SRF) represents the structure of the rock mass. It is a crude measure of the block or particle size, with the two extreme values (100/0.5 and 10/20) differing by a factor of 400. If the quotient is interpreted in units of centimetres, the extreme 'particle sizes' of 200 to 0.5 cm are seen to be crude but fairly realistic approximations. Probably the largest blocks will be several times this size and the smallest fragments less than half the size (Hoek 2007) Fracture length and end type The fracture length data distributions are both truncated and censored: truncation occurs when fractures below a certain length are ignored; censoring occurs when fracture trace lengths above a certain length cannot be observed in their entirety because of the limited dimensions of the excavation. For all fractures, both their length and end-type are mapped a fracture can end in intact rock (R), at another fracture (J), or continue beyond the tunnel (C). The distribution of fracture end data is quite similar for chainage m as it is for m. Most of the short fractures end in the rock and the long fractures continue beyond the tunnel (Figure 2-13). Note that the end-type has no correlation with the fracture set. Fracture length 20 m, n=47 Fracture length 20 m, n=30 < 20 m, n=755 < 20 m, n=276 Percentile 75 %-90 % 60 %-75 % 45 %-60 % 30 %-45 % 15 %-30 % 0 %-15 % < 5 m, n=337 < 4 m, n=733 < 3 m, n=1319 < 5 m, n=116 < 4 m, n=258 < 3 m, n=611 < 2 m, n=4000 < 2 m, n=1827 < 1 m, n=4395 < 1 m, n=2884 < 0.5 m, n=4285 RR RJ RC CC JJ JC Fracture end type (chainage ) < 0.5 m, n=4558 RR RJ RC CC JJ JC Fracture end type (chainage ) Figure Trace length and end-type for all mapped fractures in the ONKALO tunnel. For the x-axis, the fracture can end in intact rock (R), at another fracture (J), or continue beyond the tunnel (C), with the two letters, e.g. RR indicating both ends of the fracture. The mean fracture length varies from 0.5 m to 1.5 m, depending on the major fracture set. The length of the moderately dipping fractures (Set 4) seems to be greater than the length of the vertical or random fractures, but this is partly caused by the orientation of the tunnel, which biases the data (Figure 2-14).

20 % 90 % 80 % 70 % Set 1, 08 /065 Set 2, 89 /081 Set 3, 85 /359 Set 4, 32 /135 Others 60 % 50 % 40 % 30 % 20 % 10 % 0 % Fracture length (m) Figure Cumulative distribution of trace lengths for different fracture sets for all mapped fractures in the ONKALO tunnel, m chainage. 2.2 Mechanical properties of fractures The second quotient (Jr/Ja) of rock tunneling quality index (Q = RQD/Jn Jr/Ja Jw/SRF) represents the roughness and frictional characteristics of the joint walls or filling materials. This quotient is weighted in favour of rough, unaltered joints in direct contact. It is to be expected that such surfaces may be close to the peak strength, that they will dilate strongly when sheared, and they will therefore be especially favourable for tunnel stability. When rock joints have thin clay mineral coatings and fillings, the strength is reduced significantly. Nevertheless, rock wall contact after small shear displacements have occurred may be an important factor for preserving the excavation from ultimate failure. Where no rock wall contact exists, the conditions are extremely unfavourable to tunnel stability. The 'friction angles' are a little below the residual strength values for most clays, and are possibly down-graded by the fact that these clay bands or fillings may tend to consolidate during shear, at least if normal consolidation or if softening and swelling has occurred (Hoek 2007) Fracture surface parameters, Jr and Ja values The fracture roughness number, Jr, can have values between 0.5 and 4: the lowest values are for planar slickensided fractures and the highest for discontinuous or rough and undulating fractures. With increasing depth, the fractures become smoother and more planar, the mean Jr value drops from 3 to 1.5. Only the amount of long slickensided fractures is decreasing with the depth. The mean amount of slickensided fractures is less than 10 %, Figure 2-15.

21 17 The vertical N-S trending fracture set, Set 2, has more smooth and planar and fewer rough and undulating fractures than the other sets. The fracture end-type does not appear to correlate with roughness. The drillhole data were edited to 1 m long composites. The median values from the depth ranges m and m were calculated for deep drillholes (drillholes which extend at least to level z = -250 m). The median value of Jr is commonly 3 and no correlation with depth can be observed. Fracture length 20 m, n=47 Fracture length 20 m, n=30 < 20 m, n=755 < 20 m, n=276 Percentile 40 %-50 % 30 %-40 % 20 %-30 % 10 %-20 % 0 %-10 % < 5 m, n=337 < 4 m, n=733 < 3 m, n=1319 < 5 m, n=116 < 4 m, n=258 < 3 m, n=611 < 2 m, n=4000 < 2 m, n=1827 < 1 m, n=4395 < 1 m, n=2884 < 0.5 m, n= Jr value (chainage ) < 0.5 m, n= Jr value (chainage ) Figure Joint fracture roughness number Jr, and fracture length for all mapped fractures in the ONKALO tunnel, m chainage. The fracture alteration number, Ja, can have values between 0.5 and 20. The lowest values are for tightly-healed and unaltered fractures, where the rock walls are in contact, and the highest for thick mineral-filled fractures. The Ja number correlates with fracture length: the shortest fractures are more often unaltered or slightly altered (Ja is 1 or 2); whereas, the medium length and long fractures more often have softening or low friction clay mineral coatings (Ja = 4) or thin or thick mineral filling and can shear without rock wall contact (Ja 5). For chainages m, the mean Ja value is about 4. For very short fractures (length 1 m or less), the mean Ja value is 1. In the deeper part of the tunnel (chainages m), fractures are less altered. The mean Ja value for fractures with lengths varying between 0-5 m is 1. For longer fractures (20 m), the Ja value varies mainly between 2 to 3 (Figure 2-16). Compared to other sets, Set 4 has more altered fracture surfaces. The drillhole data were edited to 1 metre long composites and the median values for the depth ranges m and m were calculated for the deep drillholes (drillholes which extend at least to z = -250 m). The median value of Ja is commonly 3 and no correlation with depth can be observed.

22 18 Fracture length 20 m, n=47 Fracture length 20 m, n=30 < 20 m, n=755 < 20 m, n=276 Percentile 40 %-50 % 30 %-40 % 20 %-30 % 10 %-20 % 0 %-10 % < 5 m, n=337 < 4 m, n=733 < 3 m, n=1319 < 5 m, n=116 < 4 m, n=258 < 3 m, n=611 < 2 m, n=4000 < 2 m, n=1827 < 1 m, n=4395 < 1 m, n=2884 < 0.5 m, n= Ja value (chainage ) < 0,5 m, n= Ja value (chainage ) Figure Joint alternation number Ja, and fracture length for all mapped fractures in the ONKALO tunnel, m chainage Fracture friction angle Friction angles of the fracture surfaces can be estimated from the Jr and Ja numbers, being atan(jr/ja) (Figure 2-17). In the chainage range 0 to 1200 m, the friction angle is mainly between In the deeper part of the tunnel (chainage 1200 to 2400 m), the friction angle increases somewhat, being mainly between Between sets there is a difference in the friction angle values; these differences are illustrated further in Table 2-1. Fracture length 20 m, n=47 Fracture length 20 m, n=30 < 20 m, n=755 < 20 m, n=276 Percentile 40 %-50 % 30 %-40 % 20 %-30 % 10 %-20 % 0 %-10 % < 5 m, n=337 < 4 m, n=733 < 3 m, n=1319 < 5 m, n=116 < 4 m, n=258 < 3 m, n=611 < 2 m, n=4000 < 2 m, n=1827 < 1 m, n=4395 < 1 m, n=2884 < 0.5 m, n= Friction angle (chainage ) < 0.5 m, n= Friction angle (chainage ) Figure Friction angle and fracture length for all mapped fractures in the ONKALO tunnel, m chainage.

23 19 In the Q logging, the fracture friction angle is determined using equation +i = atan (Jr/Ja). The value thus determined is the effective friction angle and is not directly comparable with the fracture friction angle determined in the laboratory. According to the mapping data, in all sets the friction angle increases with depth. The friction angles of long fractures ( 5 m) are generally lower compared to the value of all fractures in each of the sets (Table 2-1). Between chainages m, the mean values of the friction angles of Sets 2, 3 and 4 are around 40 ; whilst in Set 1 the value is about 50. Table 2-1. Efficient joint friction angle defined from Q-logging parameters. FRACTURE SET SET 1 SET 2 SET 3 SET 4 Dip/Dip Direction 08 / / / /135 CHAINAGE m Median of friction angle (all fractures) Median of friction angle (fracture length 5 m) CHAINAGE m Median of friction angle (all fractures) Median of friction angle (fracture length 5 m) Fracture undulation Fracture undulation is defined via the amplitude of a 1 m long straight inspection line. For chainage m, the undulation is mainly mm, with the value not changing in deeper parts of the tunnel (Figure 2-18). The shortest fractures are the most planar. The main change concerns the fractures with lengths in excess of 20 m, where the mean undulation increases from 0 mm to mm. Fracture length 20 m, n=47 Fracture length 20 m, n=30 < 20 m, n=755 < 20 m, n=276 Percentile 60 %-75 % 45 %-60 % 30 %-45 % 15 %-30 % 0 %-15 % < 5 m, n=337 < 4 m, n=733 < 3 m, n=1319 < 5 m, n=116 < 4 m, n=258 < 3 m, n=611 < 2 m, n=4000 < 2 m, n=1827 < 1 m, n=4395 < 1 m, n=2884 < 0.5 m, n= cm 0-2 cm 2-5 cm 5-10 cm 10 cm Undulation (chainage ) < 0.5 m, n= cm 0-2 cm 2-5 cm 5-10 cm 10 cm Undulation (chainage ) Figure Fracture undulation and fracture length for all mapped fractures in the ONKALO tunnel, m chainage.

24 Fracture wall compressive strength The fracture wall compressive strength has been systematically mapped for the chainage range m using Schmidt hammer tests (Figure 2-19). The measured values are close to the intact rock strength for coated fracture surfaces and about 65 % of the intact rock strength for filled fracture surfaces (Figure 2-20). The uniaxial compressive strength value was derived from relation of mean value of UCS (115 MPa) and mean R- value of intact rock. Figure Schmidt hammer (type N) testing in the ONKALO (Posiva 2009) Intact Rock Filled fracture R-avarege from Schmidt hammer UCS (MPa) Chainage Figure Fracture wall compressive strength for intact rock fracture surfaces and filled fracture surfaces. 0.0

25 Fracture laboratory shear strength A few direct tests have been conducted on fracture samples to establish their shear strength. Tests with rough fracture surfaces failed. One of the satisfactory results is shown in Figure 2-21, but there are insufficient data to allow any overall conclusions to be drawn. Table 2-2. Laboratory shear test results. Sample ONK-PP74-2, 2.64 m 4 6 ONK-PP74-4, 4.25 m 8 10 ONK-PP74-7, 7.65 m 4 6 ONK-PP74-10, m 8 10 JRC smooth, but undulated, biotite surface relatively rough and stepped smooth, but undulated, biotite surface relatively rough and stepped Peak friction angle Residual friction angle Peak cohesion Residual cohesion kpa kpa Shear stress (MPa) y = 0.59x R 2 = Normal stress (MPa) Figure Shear stress - normal stress plot for sample ONK-PP74-7. Initial test at 1.0 MPa and repeat tests at 3.0 and 5.0 MPa normal stress.

26 Fracture properties from Barton-Bandis failure criterion In the Barton-Bandis failure criterion for fractures (Barton & Bandis 1990), the values of the friction angle and the cohesion can also be estimated. The criterion is non-linear and relates shear strength to the normal stress. In the criterion, the residual friction angle of the failure surface, the joint roughness coefficient (JRC) and the joint wall compressive strength (JCS) have to be known. JCS n tan r JRC log (2) n 10 r 20 20( r / R) (3) b where r is the residual friction angle b is the basic friction angle r is the Schmidt rebound number on wet and weathered surfaces R is the Schmidt rebound number on dry and unweathered sawn surfaces The instantaneous cohesion c i is calculated from: ci tan (4) n i The JRC value is estimated from the logged Jr value based on the relation presented in Barton & Bandis (1990). The JRC median values for > 5 m long fractures are quite equal between different sets and any correlation with depth cannot be observed. For the chainage range m, the JRC median values for shorter fractures (< 5 m) are lower for the Sets 2 and 3 compared to the other sets. For the chainage range m, the JRC median value for Set 1 drops clearly (Table 2-3). Figure Relation between Jr and JRC values (Barton & Bandis 1990).

27 23 Table 2-3. JRC100 (100 cm sample size) values for different sets defined from the Q- logging parameters. FRACTURE SET SET 1 SET 2 SET 3 SET 4 Dip/Dip direction 08 / / / /135 CHAINAGE m Median of JRC100 value, determined from Jr value (fracture length < 5 m) Median of JRC100 value, determined from Jr value (fracture length 5 m) CHAINAGE m Median of JRC100 value, determined from Jr value (fracture length < 5 m) Median of JRC100 value, determined from Jr value (fracture length 5 m) In the Barton-Bandis joint model, the deformation and shear strength parameter values are dependent on the normal stress, thus two different stress intervals were applied: n = 0 2 MPa and n = MPa. The lower value correspond to normal stress state near the tunnel surface while higher value is an average value of 3 between levels m. The deformation parameters are sensitive to the normal stress, but the strength parameters are not. It can be seen that the friction angles are quite similar for all fracture sets, including both short (< 5 m) fractures (Table 2-4) and long ( 5 m) fractures (Table 2-5). The cohesions of the short fractures are clearly lower than the cohesions of the long fractures, except for Set 4 where the cohesion of the short fractures is distinctly higher compared to the other sets. In the laboratory tests, the mean friction angle of the smooth fractures was 27.8 and the cohesion was 0.10 MPa, i.e. the effective shear strength of the long fractures estimated using the Barton-Bandis model is at least four times higher than for the smooth laboratory-scale factures according to these results. The effective shear strength of the short fractures is quite close to the laboratory test values (see Table 2-2).

28 24 Table 2-4. Summary of mechanical properties of fractures. Fracture length < 5 m, ONKALO chainage m. Input properties from lab. testing ALL SETS Basic friction angle of the fracture surface ( ) (1 27 JCS0 (laboratory scale) (2 115 L0 (m, for JCS and JRC in laboratory scale) ( Ln (m, natural block size) (4 1 Intact rock strength (MPa) (5 115 Estimated joint properties SET1 SET2 SET3 SET4 Dip/Dip Direction 08 / / / /135 JRCn (natural block size 100 cm) from Q-logging ( JCSn (MPa, natural block size) Normal stress n = 0-2 MPa (7 Friction angle ( ) Cohesion (MPa) Normal stiffness (GPa/m) Shear stiffness (GPa/m) Design dilatation angle ( ) Normal stress n = MPa (8 Friction angle ( ) Cohesion (MPa) Normal stiffness (GPa/m) Shear stiffness (GPa/m) Design dilatation angle ( ) ) Average residual friction angle value from laboratory tests on smooth fractures. 2) 100% of intact rock strength. 3) Specimen size at laboratory 92 mm. 4) Natural block size was selected to be equal to the block size of JRC100 value. 5) Mean strength of intact rock specimen. 6) Median values from Q-logging between chainages m. Fracture length < 5 m. In the calculations, these values were used as fixed input values. 7) Near tunnel perimeter low normal stresses are possible. 8) Mean vertical stress at 400 m depth is about 10.6 MPa.

29 25 Table 2-5. Summary of mechanical properties of fractures. Fracture length 5 m, ONKALO chainage m. Input properties from lab. testing ALL SETS Basic friction angle of the fracture surface ( ) (1 27 JCS0 (laboratory scale) (2 75 L0 (m, for JCS and JRC in laboratory scale) ( Ln (m, natural block size) (4 1 Intact rock strength (MPa) (5 115 Estimated joint properties SET1 SET2 SET3 SET4 Dip/Dip Direction 08 / / / /135 JRCn (natural block size 100 cm) from Q-logging ( JCSn (MPa, natural block size) Normal stress n = 0-2 MPa (7 Friction angle ( ) Cohesion (MPa) Normal stiffness (GPa/m) Shear stiffness (GPa/m) Design dilatation angle ( ) Normal stress n = MPa (8 Friction angle ( ) Cohesion (MPa) Normal stiffness (GPa/m) Shear stiffness (GPa/m) Design dilatation angle ( ) ) Mean residual friction angle value from lab. tests on smooth fractures. 2) 65 % of intact rock strength. 3) Specimen size at laboratory 92 mm. 4) Natural block size was selected to be equal to the block size of JRC100 value. 5) Mean strength of intact rock specimen. 6) Median values from Q-logging between chainages Fracture length 5 m. In the calculations these values was used as fixed input values. 7) Near tunnel perimeter low normal stresses are possible. 8) Mean vertical stress at 400 m depth is about 10.6 MPa.

30 26

31 27 3 BRITTLE DEFORMATION ZONES 3.1 Location of brittle deformation zone intersections Estimation of the mechanical properties of the brittle deformation zones (BDZ, BFZ) is based on Olkiluoto area drillholes and the ONKALO tunnel mapping. In this report, ten fracture zones have been analysed and the location and size of these zones is described in Kemppainen et al. (2007). One of the main BDZ zones is (OL-BFZ100) which intersect tunnel in several places (Figure 3-1). Figure 3-1. Brittle deformation zone ONK100 (OL-BFZ100). As described in that report, each zone has been checked and described via those drillholes that penetrate the zone being considered. All the intersection points are connected to each other using geophysical and hydrogeological information and, from those points, a 3D plane (to the upper and lower boundary of the brittle deformation zone) is created using the Gemcom Surpac software. The following units have been modelled to date (Mattila et al. 2007, Kemppainen et al. 2007, Posiva 2007): Seven brittle fault zones intersect the ONKALO tunnel in the m tunnel chainage range. From three of those zones (BFZ18, BFZ43 and BFZ100), the pre core zones, core zones and post core zones (i.e. chainages less than the core zone, within the core zone and greater that the core zone, respectively) have been mapped. The typical architecture is shown schematically in Figure 3-2. According to Mattila et al the brittle deformation zone can be joint zone or joint cluster (BJI) when no clear sign of lateral movement is shown. When clear signs of lateral movement is shown the zone is designated to fault zone (BFI).

32 28 Figure 3-2. A conceptual model of a single fault zone, consisting of a complex branching fault core zone (indicated in black) and an equally complex zone of influence (whose outer margins are indicated by dashed lines), from Mattila et al. (2007). From zone BFZ15, only the core has been mapped. From zones BFZ11, BFZ101 and BFZ118 only the logged Q-median value of 5 m long chainage is available (Table 3-1).

33 29 Table 3-1. Summary of brittle deformation zones intersections. Name of Brittle Deformation Zone OL-BFZ11, OL-BFZ18, OL-BFZ51 Other name Intersects ONKALO tunnel at chainages Mapped pre, core and post zones Intersections in drill holes (number) ONK19A, HZ19C x - 22 OL-BFZ18, OL-BFZ60 ONK19C, HZ19C x x 20 OL-BFZ19, OL-BFZ21, OL-BFZ98 OL-BFZ98, OL-BFZ80, OL-BFZ22 ONK20A, HZ20A ONK20B, HZ20B OL-BFZ43 ONK43 x x 1 OL-BFZ10, OL-BFZ20, OL-BFZ77, OL-BFZ84 ONK OL-BFZ100 ONK100 x x 6 OL-BFZ101 ONK101 x - 1 (pilot hole) OL-BFZ15 ONK 103 x only core mapped 9 OL-BFZ118 ONK110 x - 1 (pilot hole) In cases where the GSI value (calculated from the Q value) from tunnel mapping data is a mean value from mapped chainage, the drillhole data are used. Q is derived from Tunnelling Quality Index Q (Barton et al., 1974) Q RQD Jn Jr Ja Jw SRF, when parameters Jw and SRF are set to 1 Q = Q. Q' RQD Jn Jr Ja Value of Q can be used to estimate value of GSI: GSI 9 lnq' 44 Brittle deformation zones which are not intersected by the tunnel are classified based on drill hole logging. In cases, where the core has been determined, the GSI value for the brittle fracture zone is the value of the zone core. In the drillhole intersections, the GSI value is from the lower quartile value of the mapped data. Both approaches are conservative because the widths of the modelled zone are much wider than the actual intersections. However, at

34 30 this stage for rock mechanics modelling purposes, it was decided to characterize the brittle fault zones by the value of the weakest plane region existing in the zone. 3.2 Estimation of strength and deformability properties Determinations of the strength and deformability properties were based on the rock mass classification technique. This technique has been described by Hudson et al. (2008) and the strength and deformation properties of the brittle deformation zones were calculated based on the equations of the Hoek-Brown failure criterion (Hoek et al. 2002). For the tunnel intersections, the mapped core values of the zones were used in determining rock mass quality (e.g. Table 3-2). Table 3-2. Example of a rock mass classification result for brittle deformation zone OL- BFZ18 and OL-BFZ60. Data from Zone Intersection 2.3.xls Ri-Class RQD Jn Jr Ja Jw SRF Q Q-quality Width Q' GSI RiIII Good Pre Core Zone RiIV Fair Core Zone RiIII Good Post Core Zone The drillhole intersection locations of the zones were based on geological indications (Table 3-3). From those depth ranges, the smallest GSI values that were found were selected. The width of the range was not taken into account. For the purposes of calculation, the lower quartiles of the GSI value from different drillholes were selected (Figure 3-4). Problems associated with the influence of drillhole location and orientation on the observed structure is analyzed by Hudson et al. (2008). The problem is clearly presented in Figure 3-3.

35 31 Figure 3-3. (a) Influence of drillhole (shown in red) location and (b) drillhole orientation on the brittle deformation zone expression in a drillhole. Depending on both the location and orientation of the drillhole, the intersected expression of the zone will be different (Hudson et al. 2008).

36 32 Table 3-3. Example of geological information for the OL-BFZ018 intersections. Description from Zone Intersection 2.3.xls. Hole_id m_from m_to G_Remarks KR RiIII, BFI and DSI, KA (frac) KR Open fractures KR BJI, highly fractured KR BFI, RiIII-IV KR RiIII-IV, (BFI) KR Highly fractured KR RiIII, BFI, BJI KR Highly fractured KR RiIII KR BJI, RiIII, similar as in ONK-PH4 KR RiIV, BFI KR KA, SK alteration KR Fracturing KR BJI, RiIII KR Some fractures KR RiIV KR Fracturing KR Fracturing KR RiIII KR RiIV KR RiIII-IV PH RiII-III, Graphite and pyrite bearing section, with high water inflow (65 l/min) Average GSI value of rock mass between chainage is Average 60.7 GSI value OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR OL-KR ONK-PH Figure 3-4. Example of minimum GSI values in the drillhole intersections of brittle deformation zone OL-BFZ018.

37 Strength of the intact rock In order to determine the uniaxial compressive strength of the intact rock in a brittle deformation zone, several point loads tests from drillhole data have been evaluated. This was done in order to find if BDZ has effect to the strength of intact rock e.g. possible alteration of rock. Only a limited number of tests have been completed on samples from the brittle deformation zones, but these indicate that there is no clear difference between the uniaxial compressive strength of the intact rock within and outside a brittle deformation zone (Figure 3-5). The tested specimens may not accurately represent the strength of the intact rock in the brittle deformation zone core ( core here meaning the central part of the zone). Based on point load test results it can not be indicated that intact rock strength is lower inside BDZ compared to surrounding rock mass. Some trendsetting tests have been made with the Schmidt hammer. At chainage 1820 m (BFZ100), the strength of the rock in the brittle deformation zone core was about 11 % of the strength of the intact fresh rock. At chainage 2485 m (BFZ100), the strength of brittle deformation zone core was about 20 % of the strength of intact fresh rock. A rough estimate of the intact rock strength in the brittle deformation zone core is 20 % x 114 MPa = 22 MPa UCS [MPa] UCS, KR1- KR40 In the zones UCS, PH1-PH Borehole depth [m] Figure 3-5. Results for point load tests on samples from the brittle deformation zone cores (green circles) and comparison with the results of all other point load tests (blue and red dots) samples altogether.

38 Strength and deformability properties of brittle deformation zones The strength and deformability properties of the brittle deformation zones were estimated via RocLab-software based on the equations of the Hoek-Brown failure criterion and the results are presented in Table 3-7. Table 3-7. Strength and deformability properties of brittle deformation zones. Old zone names (format ONKxx) are in parentheses. OL-BFZ11 OL-BFZ18 OL-BFZ19 OL-BFZ22 OL-BFZ43 OL-BFZ10 OL-BFZ100 OL-BFZ101 OL-BFZ15 OL-BFZ118 OL-BFZ18 OL-BFZ60 OL-BFZ21 OL-BFZ80 OL-BFZ20 OL-BFZ51 OL-BFZ98 OL-BFZ98 OL-BFZ77 OL-BFZ84 (ONK19A) (ONK19C) (ONK20A) (ONK20B) (ONK43) (ONK56) (ONK100) (ONK101) (ONK103) (ONK110) BDZ characteristics Width (m) Rock mass quality (GSI) st quartile of drill core intersections mapped core value from tunnel intersection 1st quartile of drill core intersections 1st quartile of drill core intersections mapped core value from tunnel intersection 1st quartile of drill core intersections mapped core value from tunnel intersection mapped from one drill core intersection 1st quartile of drill core intersections mapped from one drill core intersection Strength and modulus of intact parts sigci (MPa) mi D Ei (GPa) Strength of BDZ Hoek Brown Criterion mb s a Mohr-Coulomb Fit cohesion (MPa) friction angle ( ) tensile strength (MPa) compressive strength (MPa) Deformability of BDZ Young's modulus (GPa) G = E / 2 (1+n), n = 0.25 (GPa) Equivalent Stiffness of BDZ Kn = E / width (GPa/m) * Ks = G / width (GPa/m) *) Width of the zone core varies in the drill core intersections. That is why the stiffness parameters has not been determined.

39 35 4 CONCLUSIONS In this report, the geometrical and mechanical parameters of fractures and brittle deformation zones in the vicinity of the ONKALO volume have been estimated for the tunnel chainage range m. Further analysis has been made based on core logging data from drillholes OL-KR1 OL-KR40. At this stage, the main target of the work is to obtain preliminary parameters for rock mechanics simulations and rock mechanics design. From the ONKALO tunnel mapping data, four major fracture sets can be found. In the first 250 m chainage, the horizontal set (08 /065 ) is common; it is also present in the deeper parts of the tunnel, but more sparsely. The second fracture set (89 /081 ) exists almost regularly along the whole tunnel length. The third fracture set (85 /359 ) is found more rarely. The fourth fracture set (32 /135 ), which is parallel to the foliation, is dominant from 0 to 1100 m chainage; after that, it is less frequently observed. The number of fracture sets varies with the tunnel chainage. Over the first 300 m chainage, the Jn median is 6. From chainage 300 m to about 1200 m, the Jn median is 3 and, after chainage 1200 m, the Jn median drops to 1. The decreasing number of fractures with depth is also reflected in the RQD values. The mean RQD value in the chainage range m is 99.8 %, compared to the mean value in the chainage range m of 94 %. The mean value of Jr, fracture roughness number, is 3 in the chainage range m; at greater depth (chainage m), the mean value of Jr is 1.5. The longest fractures dominate in the slickensided planar roughness category (Jr = 0.5) in the chainage range m. At greater depth (chainage ), the longer fractures become rougher (Jr = 1.5). The Ja, fracture alteration number, number correlates with fracture length: the shortest fractures are more often unaltered or slightly altered (Ja is 1 or 2); whereas, the medium length and long fractures more often have softening or low friction clay mineral coatings (Ja = 4) or thin or thick mineral filling and can shear without rock wall contact (Ja 5). In the chainage range m, the mean Ja value is about 4. For very short fractures (length 1 m or less), the mean Ja value is 1. In the deeper parts of the tunnel (chainage m), fractures are less altered. The mean Ja value for fractures with lengths varying between 0-5 m is 1. For longer fractures (20 m), the Ja value varies mainly between 2 to 3. The friction angle of the fracture surfaces has been estimated from the Jr and Ja numbers. The effect friction angle was determined using the equation +i = atan (Jr/Ja). In the chainage range 0 to 1200 m, the friction angle is mainly between In the deeper parts of the tunnel (chainage 1200 to 2400 m), the friction angle increases somewhat, being mainly between The friction angles of long fractures ( 5 m) are generally lower compared with the value of all fractures in each of the sets. Between chainages m, the mean values of the friction angles of set 2, 3 and 4 are around 40, whilst in set 1 the value is about 50. The fracture wall compressive strength has been systematically mapped for the chainage range m using the Schmidt hammer. The measured values are close to the

40 36 intact rock strength for coated fracture surfaces and about 65 % of the intact rock strength for filled fracture surfaces. Some laboratory tests for fracture shear strength at a relatively small scale have been carried out. Tests at a larger scale should also be considered, in order to obtain a better understanding of the fracture strength and deformability properties. The deformation parameters from the Barton - Bandis failure criterion are sensitive to the normal stress, but the strength parameters are not. It can be seen that the friction angles are quite similar for every fracture set, 27-32, including both short (< 5 m) fractures and long ( 5 m) fractures. The cohesions of short fractures are clearly lower, MPa, than the cohesions of the long fractures, MPa, except for Set 4 where the cohesion of short fractures is distinctly higher compared to other sets. In the laboratory tests, the average friction angle of smooth fractures was 27.8 and the cohesion was 0.10 MPa, i.e. the effective shear strength of long fractures estimated using the Barton-Bandis model is at least four times higher than smooth laboratory-scale factures according to these results. The effective shear strength of short fractures is quite near the laboratory test values. Estimation of the mechanical properties of the brittle deformation zones is based on Olkiluoto area drillholes and ONKALO tunnel mapping. In this report, ten fracture zones have been analysed. Seven brittle deformation zones intersect the ONKALO tunnel at m tunnel chainages. From three of those zones (BFZ18, BFZ43 and BFZ100), the pre core zone, core zone and post core zone has been mapped. From zone BFZ15 only the core has been mapped. From zones BFZ11, BFZ101 and BFZ118 only the logged Q-median value of 5 m long chainage is available. The cohesion of brittle deformation zones varies between MPa and friction angle between Young s modulus varies between GPa and compressive strength between MPa. The ONKALO tunnel mapping has increased the level of knowledge regarding the location and properties of brittle deformation zones. The number of strength data from such zones is still very limited. In the future, more tunnel data will be required in order to better determine the strength of the intact rock in the brittle deformation zone cores. The amount of fractures outside the major fracture sets is huge, over 80 %, which could be typical for Olkiluoto metamorphic rocks. This feature should be taken into account especially in key block analyses. Direct shear tests results are missing from vertical major fracture sets and filled moderately dipping fractures. Parametrization of BDZ is in process, in future influence zone and core parts, should be separated. More direct strength and deformability test data from the intact parts of BDZ is needed.

41 37 5 RECOMMENDATIONS The fracture parameterization should be updated after the 420 m level is reached, i.e. the deepest ONKALO level. Laboratory joint shear and normal tests are recommended for filled and coated fractures, at least three tests per each type. The results are used in various rock mechanical analyses; like key block analyses for rock support design, to estimate excavation response in discontinuous rock mass, repository scale thermo-mechanical analyses and in large scale stress-geology interaction analyses. Additional strength tests for the rock matrix of the brittle deformation zones should be done. Fault core and pre/post zones should be taken into account.

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43 39 REFERENCES Barton, N.R. & Bandis, S.C Review of predictive capabilites of JRC-JCS model in engineering practice. In Rock joints, proc. int. symp. on rock joints, Loen, Norway, (eds N. Barton and O. Stephansson), Rotterdam: Balkema. Barton, N.R., Lien, R. & Lunde, J Engineering classification of rock masses for the design of tunnel support. Rock Mech. 6(4), Engström, J. & Kemppainen, K Evaluation of the geological and geotechnical mapping procedures in use in the ONKALO access tunnel. Posiva Oy, Working Report Løset, F Practical Use of Q-method. NGI-report Norwegian Geotechnical Institute. Deere, D.U., Hendron, A.J., Patton, F.D. & Cording, E.J Design of surface and near surface construction in rock. In Failure and breakage of rock, proc. 8th U.S. symp. rock mech., (ed. C. Fairhurst), New York: Soc. Min. Engrs, Am. Inst. Min. Metall. Petrolm Engrs. Palmström, A The volumetric joint count - a useful and simple measure of the degree of rock jointing. Proc. 4th congr. Int. Assn Engng Geol., Delhi 5, Hoek, E Practical rock engineering. URL: course notes Hoek, E., Carranza-Torres, C. T. & Corkum, B Hoek-Brown failure criterion 2002 edition. Proc. North American Rock Mechanics Society meeting in Toronto in July Hudson, J. A., Cosgrove, J. & Johansson, E Estimating the mechanical properties of the brittle deformation zones at Olkiluoto. Posiva Oy, Working Report Kemppainen, K., Ahokas, T., Ahokas, H., Paulamäki, S., Paananen, M., Gehör, S. & Front, K The ONKALO area model, version 1. Posiva Oy, Working Report Mattila, J., Aaltonen, I., Kemppainen, K. Wikström, L., Paananen, M., Paulamäki, S., Front, K. Gehör, S., Kärki, A. & Ahokas, T Geological model of the Olkiluoto Site. Version 1.0. Posiva Oy, Working Report Posiva Olkiluoto Site Description 2006, Posiva Report Posiva Olkiluoto Site Description 2008, Posiva Report

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45 41 APPENDICES The following four Appendices provide further supporting information to the main body of the Report with regard to the Q parameters, more fracture geometry detail, GSI BDZ information, and the details of the Hoek-Brown failure criterion. APPENDIX 1 APPENDIX 2 APPENDIX 3 APPENDIX 4 Classification of individual parameters used in the Tunnelling Quality Index Q Fracture pole concentration contours for drillholes near the vicinity of the ONKALO tunnel. Geological indications and the GSI values for the Brittle Deformation Zones Hoek-Brown strength criterion

46 42

47 43 APPENDIX 1. Classification of individual parameters used in the Tunnelling Quality Index Q (Barton et al. 1974). 1 RQD (Rock Quality Designation) RQD A Very poor 0-25 B Poor C Fair D Good E Excellent Note: i) Where RQD is reported or measured as 10 (including 0) the nominal value 10 is used to evaluate the Q-value ii) RQD intervals of 5, i.e., 100, 95, 90, etc., are sufficiently accurate 2 Joint set number Jn A Massive, no or few joints B One joint set 2 C One joint set plus random joints 3 D Two joint sets 4 E Two joint sets plus random joints 6 F Three joint sets 9 G Three joint sets plus random joints 12 H Four or more joint sets, random, heavily jointed,.sugar-cube., etc. 15 J Crushed rock, earthlike 20 Notes: i) For tunnel intersections, use (3.0 Jn ). ii) For portals use (2.0 Jn ). 3 Joint roughness number Jr a) Rock-wall contact, and b) Rock-wall contact before 10 cm shear A Discontinuous joints 4 B Rough or irregular, undulating 3 C Smooth, undulating 2 D Slickensided, undulating 1.5 E Rough or irregular, planar 1.5 F Smooth, planar 1.0 G Slickensided, planar 0.5 Notes: i) Descriptions refer to small-scale features and intermediate scale features, in that order.

48 44 b) No rock-wall contact when sheared H J Zone containing clay minerals thick enough to prevent rock-wall contact. Sandy, gravely or crushed zone thick enough to prevent rock-wall contact Notes: ii) Add 1.0 if the mean spacing of the relevant joint set is greater than 3 m. iii) Jr = 0.5 can be used for planar, slickensided joints having lineations, provided the lineations are oriented for minimum strength. iv) Jr and Ja classification is applied to the joint set or discontinuity that is least favourable for stability both from the point of view of orientation and shear resistance, (where n tan -1 (Jr /Ja ). 4 Joint alteration number a) Rock-wall contact (no mineral fillings, only coatings) A Tightly healed, hard, non-softening, impermeable filling, i.e., quartz or epidote. r approx. Ja B Unaltered joint walls, surface staining only C D E Slightly altered joint walls. Non-softening mineral coatings, sandy particles, clay-free disintegrated rock, etc Silty- or sandy-clay coatings, small clay fraction (nonsoftening) Softening or low friction clay mineral coatings, i.e., kaolinite or mica. Also chlorite, talc, gypsum, graphite, etc., and small quantities of swelling clays. b) Rock-wall contact before 10 cm shear (thin mineral fillings) F Sandy particles, clay-free disintegrated rock, etc G H J Strongly over-consolidated non-softening clay mineral fillings (continuous, but < 5 mm thickness). Medium or low over-consolidation, softening, clay mineral fillings (continuous, but < 5 mm thickness). Swelling-clay fillings, i.e., montmorillonite (continuous, but < 5 mm thickness). Value of Ja depends on per cent of swelling clay-size particles, and access to water, etc. c) No rock-wall contact when sheared (thick mineral fillings) KL M N OP R Zones or bands of disintegrated or crushed rock and clay (see G, H, J for description of clay condition). Zones or bands of silty- or sandy-clay, small clay fraction (non-softening). Thick, continuous zones or bands of clay (see G, H, J for description of clay condition) , 8, or , 13, or 13-20

49 45 5 Joint water reduction factor A B C D E F Dry excavations or minor inflow, i.e., < 5 l/min locally. Medium inflow or pressure, occasional outwash of joint fillings. Large inflow or high pressure in competent rock with unfilled joints. Large inflow or high pressure, considerable outwash of joint fillings. Exceptionally high inflow or water pressure at blasting, decaying with time. Exceptionally high inflow or water pressure continuing without noticeable decay. approx. water pres. (kg/cm 2 ) Jw < > > Notes: i) Factors C to F are crude estimates. Increase Jw if drainage measures are installed. ii) Special problems caused by ice formation are not considered. iii) For general characterization of rock masses distant from excavation influences, the use of Jw = 1.0, 0.66, 0.5, 0.33 etc. as depth increases from say 0-5m, 5-25m, m to >250m is recommended, assuming that RQD /Jn is low enough (e.g ) for good hydraulic connectivity. This will help to adjust Q for some of the effective stress and water softening effects, in combination with appropriate characterization values of SRF. Correlations with depth-dependent static deformation modulus and seismic velocity will then follow the practice used when these were developed. 6 Stress Reduction Factor SRF a) Weakness zones intersecting excavation, which may cause loosening of rock mass when tunnel is excavated Multiple occurrences of weakness zones containing clay or A chemically disintegrated rock, very loose surrounding rock (any 10 depth). B Single weakness zones containing clay or chemically disintegrated rock (depth of excavation 50 m). 5 C Single weakness zones containing clay or chemically disintegrated rock (depth of excavation > 50 m). 2.5 D Multiple shear zones in competent rock (clay-free), loose surrounding rock (any depth). 7.5 E Single shear zones in competent rock (clay-free), (depth of excavation 50 m). 5.0 F Single shear zones in competent rock (clay-free), (depth of excavation > 50 m). 2.5 G Loose, open joints, heavily jointed or.sugar cube., etc. (any depth) 5.0 Notes: i) Reduce these values of SRF by 25-50% if the relevant shear zones only influence but do not intersect the excavation. This will also be relevant for characterization.

50 46 b) Competent rock, rock stress problems c / 1 / c SRF H Low stress, near surface, open joints. > 200 < J Medium stress, favourable stress condition K High stress, very tight structure. Usually favourable to stability, may be unfavourable for wall stability L Moderate slabbing after > 1 hour in massive rock M N Slabbing and rock burst after a few minutes in massive rock. Heavy rock burst (strain-burst) and immediate dynamic deformations in massive rock < 2 > Notes: ii) For strongly anisotropic virgin stress field (if measured): When 5 1 / 3 10, reduce c to 0.75 c. When 1 / 3 > 10, reduce c to 0.5 c, where c = unconfined compression strength, 1 and 3 are the major and minor principal stresses, and = maximum tangential stress (estimated from elastic theory). iii) Few case records available where depth of crown below surface is less than span width. Suggest an SRF increase from 2.5 to 5 for such cases (see H). iv) Cases L, M, and N are usually most relevant for support design of deep tunnel excavations in hard massive rock masses, with RQD /Jn ratios from about 50 to 200. v) For general characterization of rock masses distant from excavation influences, the use of SRF = 5, 2.5, 1.0, and 0.5 is recommended as depth increases from say 0-5m, 5-25m, m to >250m. This will help to adjust Q for some of the effective stress effects, in combination with appropriate characterization values of Jw. Correlations with depth - dependent static deformation modulus and seismic velocity will then follow the practice used when these were developed. c) Squeezing rock: plastic flow of incompetent rock / c SRF under the influence of high rock pressure O Mild squeezing rock pressure P Heavy squeezing rock pressure > Notes: vi) Cases of squeezing rock may occur for depth H > 350 Q 1/3 according to Singh Rock mass compression strength can be estimated from SIGMA cm 5 Q 1/3 c (MPa) where = rock density in t /m 3, and Q c =Q x c /100, Barton, d) Swelling rock: chemical swelling activity depending on SRF presence of water R Mild swelling rock pressure 5-10 S Heavy swelling rock pressure 10-15

51 47 APPENDIX 2. Fracture pole concentration contours for drillholes in the vicinity of the ONKALO tunnel. KR m KR m KR m KR m KR m

52 48 KR m KR m KR m KR m KR m KR m KR m

53 49 KR m KR m KR m KR m KR m KR m

54 50 KR m KR m KR m KR25B 0-40m KR m

55 51 KR m KR m KR m KR28B 0-40m KR m KR m KR31B 0-40m