深基坑承压含水层降水对地面沉降的影响

Influence of Dewatering of Confined Aquifers on Land Subsidence During Deep Excavation

随着上海超深基坑工程不断增多,使得基坑工程承压降水引起地面沉降受到重视。本文以上海某修复工程深基坑承压层减压降水施工实例,基于Biot固结理论,采用适合基坑开挖的Hardening-Soil本构模型,针对三种不同渗流特征的降水方案,通过渗流-应力耦合分析,分析探讨了深基坑承压降水施工对坑周区域地面沉降的影响因素、范围和程度。基坑降水(压)是基坑工程施工过程引起区域性地面沉降的主要原因。

With ultra- deep excavations increasing in Shanghai, the land- subsidence caused by dewatering of confined water in excavation attracts attention. Based on Biot＇ s consolidation theory, a coupling model of seepage and stress, in which the harderning - soil model was adopted to describe the non - linear characteristics of soil in foundation pit. A finite element analysis method was applied to the dewatering of a repair foundation pit in Shanghai,it was used to simulate and forecast the distribution characteristics of land subsidence deformation around the foundation pit in three kinds of groundwater dewatering projects with different flow characteristics. Then, the influencing factors and scopes of settlement in dewatering project were classified and summarized,which provided a basis for classification of monitoring region around foundation pit.