Macro-meso shear mechanical behaviors of coalescent rock joints with different morphologies
LIU Xin-rong1,2,3, XU Bin1,2,3, HUANG Jun-hui1, LIN Guang-yi1, ZHOU Xiao-han1,2, WANG Ji-wen1, XIONG Fei1
1. School of Civil Engineering, Chongqing University, Chongqing 400045, China; 2. National Joint Engineering Research Center for Prevention and Control of Environmental Geological Hazards in the TGR Area, Chongqing 400045, China; 3. Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University), Ministry of Education, Chongqing 400045, China
Abstract：To investigate the macro-meso shear mechanical behaviors of coalescent saw-tooth (wavy) rock joints considering the impact of the first-order (second-order) asperities, the laboratory direct shear tests and PFC2D numerical simulations are conducted. The results indicate that: (1) The macro-damage mass increases, the peak shear stress (displacement) approximately linearly increases (decreases) and the stress drop increases first then decreases as the first-order undulant angle increases under the same normal stress. The macro-damage increases, the peak shear stress (displacement) approximately linearly increases, and the stress drop increases (saw-tooth) or increases first then decreases (wavy) as the normal stress increases under the same first-order undulant angle. (2) There are five stages in the macro-meso damage evolution process, i.e., initial nonlinear deformation (compacting effect), approximately linear-elastic deformation (climbing effect), nonlinear deformation due to compression-shear fracture (climbing-gnawing effect), plastic deformation due to a drop in the brittle stress (gnawing effect) and ideal plastic flow deformation (sliding effect). (3) The macro-meso shear failure modes include compacting-climbing failure, climbing-gnawing failure and gnawing-sliding failure. The curves of the meso-damage crack quantity (energy) include three stages, i.e., a slight, steep and slow increase in the initial, middle and later stages, respectively, and the meso-damage particles are distributed near the rock joints in an approximately “trapezoidal-shape”. (4) According to the limit equilibrium and strength reduction methods, the rationality of shear strength estimation formulas for the rock joints is verified through the stability analysis of rock slope examples.
刘新荣, 许彬, 黄俊辉, 蔺广义, 周小涵, 王继文, 熊飞. 多形态贯通型岩体结构面宏细观剪切力学行为研究[J]. 岩土工程学报, 2021, 43(3): 406-415.
LIU Xin-rong, XU Bin, HUANG Jun-hui, LIN Guang-yi, ZHOU Xiao-han, WANG Ji-wen, XIONG Fei. Macro-meso shear mechanical behaviors of coalescent rock joints with different morphologies. Chinese J. Geot. Eng., 2021, 43(3): 406-415.
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