Abstract
The effects of the fracture scale (size) and normal stress on the shear behavior of a fracture were investigated in direct shear rig using mortar fracture replicas of different sizes (100–200 mm), which were reproduced from a tensile fracture created in granite. Monotonic shear loading was applied at normal stresses of 0.3 and 1 MPa for shear displacements of 2 and 20 mm. The change in surface topography was measured by using a profile measurement system with a laser profilometer to determine the changes in surface damage and the aperture during shear. Additionally, the effect of gouge material on the non-linearity of the closure curve during shear was investigated. The results show that the standard deviation of the initial aperture during shear increases not only with scale but also with the normal stress, since the matedness decreases due to the fact that asperities are more damaged with normal stress, and accordingly, the non-linearity in the closure curve during shear increases with normal stress. The results also show that the non-linearity of the closure curve during shear increases with the presence of gouge material/debris that is produced in the shearing process. This is mainly because gouge is soft and easily deforms under the application of normal stress. Moreover, gouge material is distributed non-uniformly around the contact areas. Thus, the normal stiffness during shear decreases not only with a decrease in the matedness between the surfaces, but also with the presence of gouge material.
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References
Abola MP, Mohanty S, and Makurat A 1996. Coupled mechanical shear and hydraulic flow behavior of natural rock joints. In: Stephansson O, Jing L, Tsang CF (eds) Coupled thermo-hydro-mechanical processes of fractured media (developments in geotechnical engineering). Elsevier, pp 393–423
Bandis S, Lumsden AC, Barton NR (1981) Experimental studies of scale effects on the shear behaviour of rock joints. Int J Rock Mech Min Sci Geomech Abstr 18:1–21
Brown SR, Scholz CH (1985) Broad bandwidth study of the topography of natural rock surfaces. J Geophys Res 90(B14):12575–12582
Chryssanthakis P, Barton N (1990) Joint roughness (JRCn) characterisation of a rock joint and joint replica at 1 m scale rock joints. In: Proceedings of the international symposium on rock joints, Loen, Norway, pp 27–33
Engelder T (1978) Aspects of asperity-surface interaction and surface damage of rocks during experimental frictional sliding. Pure Appl Geophys 116:705–716
Fardin N (2003) The effect of scale on the morphology, mechanics and transmissivity of single rock fractures. PhD Thesis, Royal Institute of Technology (KTH), Stockholm, Sweden
Giwelli AA (2010) Scale effect on the shear behavior of a fracture in the direct shear test. PhD Thesis, Tohoku University, Sendai, Japan
Giwelli AA, Sakaguchi K, Matsuki K (2009) Experimental study of the effect of fracture size on closure behavior of a tensile fracture under normal stress. Int J Rock Mech Min Sci 46:462–470
Giwelli AA, Sakaguchi K, Matsuki K (2010) Relation between fracture size and shear behavior of a single fracture in granite. In: Proceedings of Eurock 2010 Rock Mechanics, Lausanne, Switzerland, pp 211–214
Giwelli AA, Sakaguchi K, Gumati A, Matsuki K (2013) Shear behavior of fractured rock as a function of size and shear displacement. Geomech Geoeng Int J. doi:10.1080/17486025.2014.884728
Huang TH, Chang CS, Chao CY (2002) Experimental and mathematical modeling for fracture of rock joint with regular asperities. Eng Fract Mech 69:1977–1996
Isakov E, Ogilvie SR, Taylor CW, Glover PWJ (2001) Fluid flow through rough fractures in rocks I: high resolution aperture determinations. EPSL 191:267–282
Maltman A (1994) The geological deformation of sediments. Chapman & Hall, London
Matsuki K, Lee JJ, Sakaguchi K (1999) Size effect in flow conductance of a closed small-scale hydraulic fracture in granite. Geotherm Sci Tech 6:113–138
Matsuki K, Chida Y, Sakaguchi K, Glover PWJ (2006) Size effect on aperture and permeability of a fracture as estimated in large synthetic fractures. Int J Rock Mech Min Sci 43:726–755
Matsuki K, Wang EQ, Giwelli AA, Sakaguchi K (2008) Estimation of closure of a fracture under normal stress based on aperture data. Int J Rock Mech Min Sci 45:194–209
Olsson WA (1992) The effect of slip on the flow of fluid through a fracture. Geophys Res Lett 19(6):541–543
Power WL, Tullis TE, Brown SR, Boinott GN, Scholz CH (1987) Roughness of natural fault surfaces. Geophys Res Lett 14:29–32
Sakaguchi K, Tomono J, Okumura K, Ogawa Y, Matsuki K (2008) Asperity height and aperture of a artificial tensile fracture of metric size. Rock Mech Rock Eng 41(2):325–341
Teufel LW (1987) Permeability changes during shear deformation of fractured rock. In: Proceedings of the 28th US symposium on rock mechanics, Tusson, Arizona, pp 473–480
Yoshinaka R, Yoshida J, Shimizu T, Arai H, Arisaka S (1991). Scale effect in shear strength and deformability of rock joints. In: Proceedings of the 7th ISRM congress on rock mechanics, Aachen, Germany, pp 371–374
Yoshinaka R, Arisaka S, Sasaki K, Yoshida J (1995) Mechanism of scale effect in rock joint. In: Proceedings of the international workshop on rock foundation, Tokyo, Japan, pp 223–228
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This study was sponsored by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) Japan (Grant No. 19360402). This support is gratefully acknowledged.
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Giwelli, A.A., Gumati, A., Sakaguchi, K. et al. Effects of Scale and Normal Stress on Shear Behavior of a Soft Fracture Replica. Geotech Geol Eng 32, 673–686 (2014). https://doi.org/10.1007/s10706-014-9743-x
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DOI: https://doi.org/10.1007/s10706-014-9743-x