|
|
|
| DISCUSSION ABOUT GRASSELLI?S PEAK SHEAR STRENGTH CRITERION FOR ROCK JOINTS |
| TANG Zhicheng1，2，XIA Caichu1，2，SONG Yinglong1，2，LIU Ting1，2 |
| (1. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education，Tongji University，Shanghai 200092，China；2. Department of Geotechnical Engineering，Tongji University，Shanghai 200092，China) |
|
|
|
|
Abstract The major problem in determining the shear strength of rock joints is how to measure and then express the joint roughness with a number or a mathematical function according to joint morphology. Joint roughness coefficient(JRC) is probably the most commonly used method to measure roughness of rock joint surfaces. The method of evaluating JRC of joint is by visual comparison of measured profiles against a set of standard JRC profiles produced by Barton and Choubey. However，JRC estimation by visual comparison is prone to subjectivity and based on the analysis of only a single profile in the direction of shearing and usually underestimates joint roughness. The right method should be based on three-dimensional topography of joint surface. During shear tests，it is observed that the common characteristic among all the contact areas is that they are located in the steepest zones facing the shear direction. There is a parabolic function relationship between the potential contact area and the apparent dip angle. This function is a manifestation of real three-dimensional joint surface morphology information. Based on 42 direct shear test results，the relationship between peak shear dilatancy angle and three-dimensional morphology parameters is presented，and then a new shear strength criterion is proposed. All the parameters are determined according to joint topography. The new criterion follows the standard form of Mohr-Coulomb formula and has a explicit physical meaning. Finally，priority between two shear strength criteria is analyzed and how to use the new criterion is also suggested.
|
|
Received: 12 August 2011
|
|
|
|
| [1] PATTON F D. Multiple modes of shear failure in rock[C]// Proceedings of the First Congress of International Society of Rock Mechanics. Lisbon，Portugal：[s.n.]，1966：509–513.
[2] LADANYI B，ARCHAMBAULT G. Simulation of the shear behavior of a jointed rock mass[C]// Proceedings of the 11th US Symposium on Rock Mechanics. Berkeley，US：[s.n.]，1970：105–125.
[3] BARTON N，CHOUBEY V. The shear strength of rock joints in theory and practice[J]. Rock Mechanics and Rock Engineering，1977，10(1/2)：1–54.
[4] AMADEI B，WIBOWO J，STURE S，et al. Applicability of existing models to predict the behavior of replicas of natural fractures of welded tuff under different boundary conditions[J]. Geotechnical and Geology Engineering，1998，16(1)：79–128.
[5] International Society for Rock Mechanics. Suggested methods for the quantitative description of discontinuities in rock masses[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1978，15(2)：319–368.
[6] BEER A J，STEAD D，COGGAN J S. Technical note estimation of the joint roughness coefficient(JRC) by visual comparison[J]. Rock Mechanics and Rock Engineering，2002，35(1)：65–74.
[7] HSIUNG S M，GHOSH A，AHOLA M P，et al. Assessment of conventional methodologies for joint roughness coefficient determination[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1993，30(7)：825–829.
[8] HUANG S L，OELFKE S M，SPECK R C. Applicability of fractal characterization and modeling to rock joint profiles[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1992，29(1)：89–98.
[9] XIE H P，WANG J A，KWASNIEWSKI M A. Multi-fractal characterization of rock fracture surfaces[J]. International Journal of Rock Mechanics and Mining Sciences，1999，36(1)：19–27.
[10] ODLING N E. Natural fracture profiles，fractal dimension and joint roughness coefficients[J]. Rock Mechanics，1994，27(3)：135–153.
[11] REEVES M J. Rock surface roughness and frictional strength[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1985，22(6)：429–442.
[12] TSE R，CRUDEN D M. Estimating joint roughness coefficients[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1979，16(5)：303–307.
[13] KULATILAKE P H S W，SHOU G，HUANG T H，et al. New peak shear strength criteria for anisotropic rock joints[J]. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts，1995，32(7)：673–697.
[14] HONG E S，LEE J S，LEE I M. Underestimation of roughness in rough rock joints[J]. International Journal for Numerical and Analytical Methods in Geomechanics，2008，32(11)：1 385–1 403.
[15] GENTIER S，RISS J，ARCHAMBAULT G，et al. Influence of fracture geometry on sheared behavior[J]. International Journal of Rock Mechanics and Mining Sciences，2000，37(1/2)：161-174.
[16] HOMAND F，BELEM T，SOULEY M. Friction and degradation of rock joint surfaces under shear loads[J]. International Journal for Numerical and Analytical Methods in Geomechanics，2001，25(10)：973–999.
[17] BELEM T，HOMAND F，SOULEY M. Quantitative parameters for rock joint surface roughness[J]. Rock Mechanics and Rock Engineering，2000，33(4)：217–242.
[18] GRASSELLI G. Shear strength of rock joints based on quantified surface description[Ph. D. Thesis][D]. Switzerland：Swiss Federal Institute of Technology，2001.
[19] GRASSELLI G，WIRTH J，EGGER P. Quantitative three-dimensional description of a rough surface and parameter evolution with shearing[J]. International Journal of Rock Mechanics and Mining Sciences，2002，39(6)：789–800.
[20] GRASSELLI G，EGGER P. Constitutive law for the shear strength of rock joints based on three-dimensional surface parameters[J]. International Journal of Rock Mechanics and Mining Sciences，2003，40(1)：25–40.
[21] COTTRELL B E. Updates to the GG-shear strength criterion[M. S. Thesis][D]. Toronto，Canada：University of Toronto，2009.
[22] JING L. Numerical modeling of jointed rock masses by distinct element method for two- and three-dimensional problems[Ph. D. Thesis][D]. Lulea，Sweden：Lulea University of Technology，1990.
[23] ASADOLLAHI P. Stability analysis of a single three-dimensional rock block：effect of dilatancy and high-velocity water jet impact[Ph. D. Thesis][D]. Austin，USA：University of Texas at Austin，2009. |
|
|
|
2012, Vol. 31 
