NUMERICAL SIMULATION OF DIRECT SHEAR TESTS FOR ROCK AND SOIL MIXTURE IN A LANDSLIDE BASED ON BONDED-PARTICLE MODEL
ZHOU Jian1，2，ZHANG Luqing1，DAI Fuchu1，MIN Hong3
(1. Key Laboratory of Engineering Geomechanics，Institute of Geology and Geophysics，Chinese Academy of Sciences，Beijing 100029，China；2. Graduate University of Chinese Academy of Sciences，Beijing 100049，China；3. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Science，
Wuhan，Hubei 430071，China)
Abstract：The elementary process of establishing numerical model based on digital image processing is introduced. According to the method，the particle flow numerical models of soil and rock mixture(SRM) can be obtained directly by field digital photos. Taking SRM in a landslide near the dam of Xiluodu hydropower station for example，the numerical model is established by field photo. The micro-mechanical parameters of gravel and soil are well studied by using the particle flow code in two dimensions(PFC2D)；and micro-mechanical parameters corresponding to their macro-mechanical features are selected. The numerical simulation of direct shear test for the SRM is conducted under serious normal pressures and the results of SRM are compared with those of heterogeneous soil. The main research results can be summarized as follows：Firstly，the microparameters of soil inversely calculated by biaxial compression test is used in direct shear test to get macroparameters of soil；and these macroparameters are consistent with practice. Compared with heterogeneous soil，the initial shear stiffness of the SRM with certain content gravel is higher，and the shear displacement required for the SRM reaching to its peak shear strength is reduced. Under the assumption that the bonded strength between gravel and soil is one tenth of the soil?s，the internal friction angle of the SRM is larger，while the cohesion is lower. Compared with the fracture plane in heterogeneous soil model after direct shear tests，the cracks developed in the SRM numerical model can be divided into two parts：some are around the shear plane formed broad fractures band，the others distribute between gravel and soil. Also according to the characters of shear failure，the reason for enhancing shear performance of the SRM which contains a certain amount of gravel can be introduced qualitatively.
周 剑1，2，张路青1，戴福初1，闵 弘3. 基于黏结颗粒模型某滑坡土石混合体直剪试验数值模拟[J]. 岩石力学与工程学报, 2013, 32(s1): 2650-2659.
ZHOU Jian1，2，ZHANG Luqing1，DAI Fuchu1，MIN Hong3. NUMERICAL SIMULATION OF DIRECT SHEAR TESTS FOR ROCK AND SOIL MIXTURE IN A LANDSLIDE BASED ON BONDED-PARTICLE MODEL. , 2013, 32(s1): 2650-2659.
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2013, Vol. 32 
