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依据离心模型试验设计方案,建立三维有限元模型对上海地区某紧邻地铁超深基坑变形特性进行数值模拟。在数值模型中,地铁隧道和连续墙均采用单层shell单元模拟,支撑体系采用梁单元模拟,土体的本构关系则分别采用考虑土体小应变特性的HSS模型和考虑弹塑性特性的Mohr-Column模型进行描述。通过与离心模型试验结果的对比分析,表明考虑土体小应变特性的HSS模型能够较好地模拟超深基坑的变形特性,同时也对离心模型试验的不足之处进行适当的补充和解释。
According to the centrifugal model test design scheme, a three-dimensional finite element model was established to simulate the deformation characteristics of an ultra-deep foundation pit adjacent to the subway in Shanghai. In the numerical model, both the subway tunnel and the continuous wall are modeled as single-layer shell elements. The support system is simulated by beam elements. The constitutive relation of the soil is respectively considered by the HSS model considering the small strain of the soil and the Mohr -Column model to describe. By comparing with the centrifugal model test results, it is shown that the HSS model considering the small strain of soils can simulate the deformation characteristics of the ultra deep foundation pit well. Meanwhile, the inadequacies of the centrifuge model test can be properly supplemented and explained.