Experimental study on the influence of clay particle contents on the stability of soil caves
LIU Xiumin1，2，CHEN Congxin1，2，YU Qunqun3，XIA Kaizong1，2，LIU Xuanting1，2，WANG Yue1，2
(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，China；3. School of Civil Engineering and Architecture，Anhui University of Science and Technology，Huainan，Anhui 232001，China)
Abstract：The urban ground collapse that often occurs is mainly soil cave collapse，and the contents of clay particles in the bedrock overburden have an important influence on the stability of soil caves. Clay particles mainly containing kaolinite are selected and mixed with coarse silt particles to form a remolded soil cap layer with different percentages of clay particles. The relationship between the contents of clay particles and the permeability coefficient of the soil layer is obtained through experiments. According to the permeability coefficient，the experimental soil layers are divided into two basic layer structures，namely，water-permeable and water-blocking cover layers. The stability of spherical soil holes with different radii in these two types of soil caps is studied through indoor model tests. The results show that stable soil caves cannot be formed in sandy soil caps without clay particles，and that the permeable soil caps cannot form large soil caves and the small soil caves have poor stability. It is also revealed that the water-blocking soil cap layers can form large soil caves close to the critical roof thickness，that the stability of the soil caves increases with increasing the clay particle content and that the soil cave with a clay particle content about 30% has the best stability. Based on the test results and engineering phenomena，the common ground collapses of the overburden are divided into two types including dish-shaped collapse and cylindrical collapse，and their damage mechanisms and hazards are explained.
刘秀敏1，2，陈从新1，2，于群群3，夏开宗1，2，刘轩廷1，2，王 月1，2. 黏土颗粒含量对土洞稳定性影响试验研究[J]. 岩石力学与工程学报, 2021, 40(9): 1914-1922.
LIU Xiumin1，2，CHEN Congxin1，2，YU Qunqun3，XIA Kaizong1，2，LIU Xuanting1，2，WANG Yue1，2. Experimental study on the influence of clay particle contents on the stability of soil caves. , 2021, 40(9): 1914-1922.
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2021, Vol. 40 
