邻近地铁基坑不同工况对周边环境的影响分析

Analysis of Infl uence of Different Working Conditions of Adjacent Subway Foundation Pit on Surrounding Environment

上海普陀区真如社区某项目基坑东北侧邻近地铁盾构区间,常规的施工工况为先施工大基坑出±0 m后,邻近地铁区域的小坑再逐一施工;由于本工程工期紧张,施工前采用2D Plaxis有限元软件对原设计工况和相邻基坑相互配合开挖工况进行模拟计算,结果得出两工况对周边环境的影响基本相同。同时,对中隔墙最不利工况进行了受力分析,且对土方开挖进行前期策划,最终采用相互配合开挖的施工工况进行施工。监测结果表明,该施工工况对周边环境的影响很小,位移在规范范围内,取得了业主的一致好评,可以给类似的基坑工程提供一定的施工依据。

The northeast side of the foundation pit of a project in Zhenru Community,Putuo District,Shanghai is adjacent to the subway shield interval.The conventional construction condition is firstly to construct a large foundation pit up to level±0 m,and then construct small pits adjacent to the subway area one by one.Due to the tight construction period of the project,2D Plaxis finite element software is used to simulate the original design condition and the excavation condition of adjacent foundation pits.The results show that the two conditions have basically the same impact on the surrounding environment.At the same time,the stress analysis of the most unfavorable working conditions of the middle partition wall is carried out,and the preliminary planning of earth excavation is carried out.Finally,it is decided to adopt the construction conditions of mutual cooperation excavation for construction.The monitoring results show that the construction condition has little impact on the surrounding environment,and the displacement is within the specification range,which has been highly praised by the owner,and can provide a certain construction basis for similar foundation pit projects.