Abstract：Numerical model of rock joint was generated and direct shear tests at different normal stresses were conducted using PFC2D. Shear behavior of the rock joint，along with development and evolution law of microcracks at different normal stresses were examined. It is shown that the shear behavior of simulated joints corresponds well to that observed in real joints；and the dependencies of shear strength and peak dilatation angle on normal stresses conform well to predict results of the JRC-JCS model. Compressive contact force mainly concentrates nearby asperities on both sides of the joint plane. The larger the normal stress is，the more concentrated areas of confact force will appear，and the higher the concentration degree is. As normal stress continues to enhance，the developing rate of microcracks within the specimen gradually increases；and the proportion of shear cracks to the total number of microcracks gradually enlarges；but they still far less than the tension cracks. The distribution characteristics of compressive contact force on joint surface are consistent with the development law of microcracks in the specimen. Shear failure of joint under external load results from convergence and correlation of microcracks in the joint plane；and the effect of compression induced tensile cracking plays a dominant role in the process of joint shear failure.
刘 博，李海波，朱小明. 循环剪切荷载作用下岩石节理强度劣化规律试验模拟研究[J]. 岩石力学与工程学报，2011，30(10)：2 033- 2 039.(LIU Bo，LI Haibo，ZHU Xiaoming. Experiment simulation study of strength degradation of rock joints under cyclic shear loading[J]. Chinese Journal of Rock Mechanics and Engineering，2011，30(10)：2 033-2 039.(in Chinese))
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2013, Vol. 32 
