市政工程基坑开挖对既有隧道影响有限元建模分析

Analysis on Effective Interaction between Municipal Engineering Deep Foundation Pit Excavation and Existing Tunnel by Finite Element Method

由于城市对市政工程项目的需求与日俱增,市政工程项目中难免出现深基坑开挖施工,容易对城市既有沟槽管线造成附加应力,使既有项目产生拉裂等事故。结合工程实践,采用三维有限元方法,分析基坑开挖对坑底已建隧道的影响,包括数值分析的模型网格划分、模型力学参数及单元类型选择和开挖进程模拟及监测面设置。分析结果表明,处于坑底中心的隧道,其横截面在基坑开挖过程的最大直径改变发生在竖向与水平向,竖向伸长,水平向压缩。处于坑底靠近地连墙的隧道,绕垂直轴向在坑内旋转一定的角度。

As the city of the increasing demand for public works projects,public works projects will inevitably lead to deep excavation,the trench lines of both the city is easy to cause additional stress,resulting in rupture of both the project and other accidents occur there.Built with a project practice,three-dimensional finite element method to analyze the Bottom of excavation of the tunnel has been built,including numerical analysis of model meshing,and mechanical parameters of the model unit type selection and surface excavation process modeling and monitoring set.The results show that,at the Bottom of the center tunnel,the cross-section of the excavation process of change in maximum diameter vertical and horizontal,vertical stretch,horizontal compression.Even the walls at the bottom of the pit near the tunnel,pit rotated around the vertical axis angle.