净砂与胶结砂土Trapdoor试验离散元数值模拟<br />-《地球科学与环境学报》

文章信息/Info

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

作者:: 蒋明镜; 杜文浩; 奚邦禄; 1.同济大学地下建筑与工程系，上海 200092； 2.同济大学土木工程防灾国家重点实验室，上海 200092； 3.同济大学岩土及地下工程教育部重点实验室，上海 200092

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

摘要:: Trapdoor试验是一种广泛应用于隧道工程中的研究方法，可以对隧道开挖等引起的结构上应力分布变化进行分析。利用净砂与胶结砂土Trapdoor试验离散元模拟研究土体破坏形态、自由门上土压力分布、颗粒位移以及颗粒转动情况。结果表明：净砂和胶结砂土破坏形态相似，从自由门中心向两侧可以划分为破坏区、剪切带以及影响区域；破坏区内颗粒位移较大，剪切带内颗粒转动明显；与净砂相比，胶结砂土破坏土体表面形成裂缝，由于胶结的存在使得剪切带较窄，土体破坏范围和自由门上土压力都较小。

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.