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Title:: Distinct Element Numerical Simulation of Trapdoor Tests for Pure and Cemented Sands

Author(s):: JIANG Ming-jing; DU Wen-hao; XI Bang-lu; 1. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China; 2. State Key Laboratory of Disaster Reduction in Civil Engineering, Tongji University, Shanghai 200092, China; 3. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China

Keywords:: geotechnical engineering; pure sand; cemented sand; distinct element simulation; trapdoor test; failure mode; soil pressure

Abstract:: The trapdoor test is an experimental method widely employed in the tunnel engineering to investigate the variation of the stress distribution on engineering structure caused by the tunnel excavation. The soil failure mode, distribution of soil pressure on the trapdoor, particle displacement and particle rotation were investigated by the distinct element simulation of trapdoor tests for pure and cemented sands. The results show that the failure mode of the cemented sands is similar to that of the pure sands; the soil fails at the end of the test with the damage zone, the shear band and the influential zone formed from the center of the trapdoor to the sides of the ground; the particle displacement in the damage zone is relatively large, and the particle rotation in the shear band is relatively obvious; compared with pure sands, the cemented sands fail with several cracks on the surface, and two narrow shear bands because of the cementation; the range of soil damage zone and the soil pressure on the trapdoor of the cemented sands are smaller than those of pure sands.