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| Initial-disintegration analysis of granite residual soil and approximate simulation of mathematical morphology#br# |
| LI Chengsheng1，2，AN Ran1，2，SHU Rongjun1，2，KONG Lingwei1#br# |
(1. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；2. University of Chinese Academy of Sciences，Beijing 100049)
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Abstract Moisture content is an important factor affecting the disintegration characteristics of granite residual soil，and transient infiltration is an important reason for initial disintegration. In order to better understand the unsaturated effective stress state of granite residual soil under transient infiltration in the initial stage of disintegration，the unsaturated effective stress in the disintegration process was approximately simulated by mathematical morphological method. The disintegration tests on different water content samples were carried out，and the unsaturated effective stress under different saturations was calculated by 18-lattice method based on the Pore Algorithm(PM) method. The approximate simulation of initial disintegration process was performed in combination with transient infiltration method，and the disintegration mechanism was analyzed from the perspective of unsaturated effective stress. The experimental results show that the disintegration curve of granite residual soil has significant two-stage characteristics and presents a“S”shape in the initial stage of disintegration. The initial disintegration rate increases with decreasing the water content. The simulation results show that the gas inside the sample can not be exhausted in time during the transient infiltration stage，resulting in that the pore pressure inside the sample increases rapidly and tends to be stable in a certain range，and that the synthetic unsaturated force between particles rapidly decays to zero and the decay rate is faster with a lower initial saturation. If the initial saturation is low enough，the synthetic unsaturated force will suddenly become negative at the moment of infiltration，that is，a tensile stress occurs inside the soil. If the tensile stress is greater than the strength between soil particles，the microscopic structure of the soil will be destroyed，which corresponds to the initial disintegration failure.
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2020, Vol. 39 
