Laboratory Investigation on Shear Behavior of Rock Joints and a New Peak Shear Strength Criterion

In this study, shear tests on artificial rock joints with different roughness were conducted under five normal stress levels. Test results showed that the shear strength of rock joints had a positive correlation with roughness and the applied normal stress. Observation of joint specimens after shear tests indicated that asperity damage was mainly located in the steep areas facing the shear direction. The damaged joint surfaces tend to be rough, which implies that tensile failure plays an important role in shear behavior. As a result of the anisotropic characteristic of joint roughness, two quantitative 2D roughness parameters, i.e., the revised root-mean-square of asperity angle tan−1(Z2r) and the maximum contact coefficient Cm, were proposed considering the shear direction. The proposed roughness parameters can capture the difference of roughness in forward and reverse directions along a single joint profile. The normalized tensile strength and the proposed roughness parameters were used to perform a rational derivation of peak dilatancy angle. A negative exponential-type function was found to be appropriate to model the peak dilatancy angle. Using the new model of peak dilatancy angle, we obtained a new criterion for peak shear strength of rock joints. The good agreement between test results and predicted results by the new criterion indicated that the proposed criterion is capable of estimating the peak shear strength of rock joints. Comparisons between the new criterion and published models from available literature revealed that the proposed criterion has a good accuracy for predicting the peak shear strength of joints investigated in this study.

[1]  Lu Zhang,et al.  A new method estimating the 2D Joint Roughness Coefficient for discontinuity surfaces in rock masses , 2014 .

[2]  Giovanni Grasselli,et al.  Manuel Rocha Medal Recipient Shear Strength of Rock Joints Based on Quantified Surface Description , 2006 .

[3]  Chuangbing Zhou,et al.  Stability analysis and treatment of a reservoir landslide under impounding conditions: a case study , 2015, Environmental Earth Sciences.

[4]  S. C. Lo,et al.  Reassessing the Joint Roughness Coefficient (JRC) Estimation Using Z2 , 2001 .

[5]  D. Cruden,et al.  ESTIMATING JOINT ROUGHNESS COEFFICIENTS , 1979 .

[6]  M. Ahola,et al.  Assessment of conventional methodologies for joint roughness coefficient determination , 1993 .

[7]  N. Odling,et al.  Natural fracture profiles, fractal dimension and joint roughness coefficients , 1994 .

[8]  Giovanni Grasselli,et al.  Constitutive law for the shear strength of rock joints based on three-dimensional surface parameters , 2003 .

[9]  Caichu Xia,et al.  New Peak Shear Strength Criterion of Rock Joints Based on Quantified Surface Description , 2014, Rock Mechanics and Rock Engineering.

[10]  Zon-Yee Yang,et al.  On the applicability of self-affinity concept in scale of three-dimensional rock joints , 2011 .

[11]  T. Kwon,et al.  Observation of the Degradation Characteristics and Scale of Unevenness on Three-dimensional Artificial Rock Joint Surfaces Subjected to Shear , 2015, Rock Mechanics and Rock Engineering.

[12]  Yujing Jiang,et al.  Estimating the relation between surface roughness and mechanical properties of rock joints , 2006 .

[13]  Pinnaduwa Kulatilake,et al.  Natural rock joint roughness quantification through fractal techniques , 2006 .

[14]  Heping Xie,et al.  Multifractal characterization of rock fracture surfaces , 1999 .

[15]  Giovanni Grasselli,et al.  Shear strength of rock joints based on quantified surface description , 2001 .

[16]  Lanru Jing,et al.  Numerical modelling of jointed rock masses by distinct element method for two- and three-dimensional problems , 1990 .

[17]  N. Barton,et al.  The shear strength of rock joints in theory and practice , 1977 .

[18]  E. T. Brown.  Rock characterization, testing & monitoring: ISRM suggested methods , 1981 .

[19]  M. J. Reeves,et al.  Rock surface roughness and frictional strength , 1985 .

[20]  H. J. Schneider,et al.  The friction and deformation behaviour of rock joints , 1976 .

[21]  Jae-Joon Song,et al.  Numerical simulation of a direct shear test on a rock joint using a bonded-particle model , 2009 .

[22]  A. Ghazvinian,et al.  The Shear Behavior of Bedding Planes of Weakness Between Two Different Rock Types with High Strength Difference , 2010 .

[23]  G. Grasselli,et al.  A new 2D discontinuity roughness parameter and its correlation with JRC , 2010 .

[24]  Jung-Wook Park,et al.  Model for the shear behavior of rock joints under CNL and CNS conditions , 2014 .

[25]  J. C. Jaeger.  Friction of Rocks and Stability of Rock Slopes , 1971 .

[26]  Tikou Belem,et al.  Friction and degradation of rock joint surfaces under shear loads , 2001 .

[27]  N. Barton,et al.  Strength, deformation and conductivity coupling of rock joints , 1985 .

[28]  Pinnaduwa Kulatilake,et al.  New peak shear strength criteria for anisotropic rock joints , 1995 .

[29]  Qinghui Jiang,et al.  Numerical simulation of damage and failure in brittle rocks using a modified rigid block spring method , 2015 .

[30]  John Coggan,et al.  Technical Note Estimation of the Joint Roughness Coefficient (JRC) by Visual Comparison , 2002 .

[31]  Jun Peng,et al.  New Rock Bolt Model and Numerical Implementation in Numerical Manifold Method , 2017 .

[32]  M. Souley,et al.  Quantitative Parameters for Rock Joint Surface Roughness , 2000 .

[33]  Seong-seung Kang,et al.  Determination of Joint Roughness Coefficients Using Roughness Parameters , 2014, Rock Mechanics and Rock Engineering.

[34]  Zon-Yee Yang,et al.  Effect of asperity order on the shear response of three-dimensional joints by focusing on damage area , 2010 .

[35]  R. C. Speck,et al.  APPLICABILITY OF FRACTAL CHARACTERIZATION AND MODELLING TO ROCK JOINT PROFILES , 1992 .

[36]  Louis Ngai Yuen Wong,et al.  New Criterion for Evaluating the Peak Shear Strength of Rock Joints Under Different Contact States , 2016, Rock Mechanics and Rock Engineering.

[37]  Pinnaduwa Kulatilake,et al.  Requirements for accurate quantification of self affine roughness using the roughness-length method , 1997 .

[38]  B. Ladanyi,et al.  Simulation Of Shear Behavior Of A Jointed Rock Mass , 1969 .

[39]  P. Rivard,et al.  Geometric Effect of Asperities on Shear Mechanism of Rock Joints , 2016, Rock Mechanics and Rock Engineering.

[40]  Ömer Aydan,et al.  The anisotropy of surface morphology characteristics of rock discontinuities , 1996 .

[41]  Liu Ting.  DISCUSSION ABOUT GRASSELLI S PEAK SHEAR STRENGTH CRITERION FOR ROCK JOINTS , 2012 .

[42]  Norbert H. Maerz,et al.  Joint roughness measurement using shadow profilometry , 1990 .

[43]  Kwang-Ho You,et al.  Influence of asperity degradation on the mechanical behavior of rough rock joints under cyclic shear loading , 2001 .

[44]  M. Maksimović,et al.  New description of the shear strength for rock joints , 1992 .

[45]  Jae-Joon Song,et al.  Numerical method for the determination of contact areas of a rock joint under normal and shear loads , 2013 .

[46]  J. P. Seidel,et al.  Towards an understanding of joint roughness , 1995 .

[47]  Shigui Du,et al.  Measurement of joint roughness coefficient by using profilograph and roughness ruler , 2009 .

[48]  Giovanni Grasselli,et al.  Quantitative three-dimensional description of a rough surface and parameter evolution with shearing , 2002 .

[49]  Michael E. Plesha,et al.  Constitutive models for rock discontinuities with dilatancy and surface degradation , 1987 .

[50]  Stephen R. Brown,et al.  Broad bandwidth study of the topography of natural rock surfaces , 1985 .

[51]  G. Barla,et al.  A Laboratory Shear Cell Used for Simulation of Shear Strength and Asperity Degradation of Rough Rock Fractures , 2013, Rock Mechanics and Rock Engineering.

[52]  Chuangbing Zhou,et al.  Modelling of hydro-mechanical coupling and transport in densely fractured rock mass , 2015 .

[53]  M. Maksimović,et al.  The shear strength components of a rough rock joint , 1996 .

[54]  F. Patton.  Multiple Modes of Shear Failure In Rock , 1966 .

[55]  Xianbin Yu,et al.  Joint profiles and their roughness parameters , 1991 .

[56]  A. Ghazvinian,et al.  Importance of Tensile Strength on the Shear Behavior of Discontinuities , 2012, Rock Mechanics and Rock Engineering.