残积土中地铁隧道的有限元分析

Analysis on the Tunnel of Metro in Eluvial Soil by Finite Element Method

对巴西圣保罗市地铁扩建项目的弹塑性有限元分析进行了讨论。对原状土样做了试验以研究残积土的本构特性,并确定了一个不相关联的弹塑性本构模型,使其反映在地铁隧道开挖典型应力路径下残积土的特性。提出了模拟开挖的应力释放法,根据这一方法可用二维有限元计算在隧道开挖三维过程中土体的响应,从隧道的实测结果与有限元计算的结果对比中可看出两者比较吻合。

Anumerical analysis of a shallow tunnel through residual soils is presented in this paper. The tunnel was constructed as part of the expansion of the underground transit system in the city of San Paulo, Brazil. Laboratory tests were performed to simulate the behavior of the soil under the stress path of tunnel excavation. Results were used to get the parameters of Lade constitutive model. Methods of FEM to model the process of excavation are discussed in this paper. The calculation results are com- pared with the results either of Peck empirical formula or of monitoring. Good agreements can be observed between them.