南通市南山湖综合楼基坑工程降水数值模拟分析

Numerical Simulation Analysis on Dewatering in Foundation Pit Project of Nanshanhu Comprehensive Building in Nantong

摘要:

基坑降水的成功与否，关系到整个基坑的安全。南通市南山湖综合楼基坑开挖过程中虽建立了止水帷幕，但仍需对基坑降水的方案进行安全评估。采用MIDAS/GTS数值分析软件建立三维渗流模型，通过对现场单井抽水试验进行模拟分析，综合地勘报告中室内试验渗透系数和抽水试验的渗透系数，反向推演出符合工程实际的渗流边界函数和渗透系数；然后利用反推得到的计算参数，建立三维渗流模型，模拟群井抽水状态下水位降深与时间的变化关系，对群井降水效果进行分析，验证降水井设计是否合理，指导基坑土方的开挖。

关键词:基坑降水;抽水试验;群井抽水;渗流模型;安全评价

Abstract:

Foundation pit dewatering is the key to the whole foundation pit safety. Although the waterproof curtain was built in the foundation pit excavation of Nanshanhu complex building in Nantong, it is still necessary to make a safety assessment on the dewatering scheme of the foundation pit. 3-dimensional seepage model is established by using the MIDAS/GTS numerical analysis software, by the simulating analyzing a single well pumping test in the field and synthesizing the permeability coefficients of indoor tests in the geological exploration report and pumping tests, the seepage boundary function and the permeability coefficients fitted for the practical engineering situation are inversely deduced; then the 3-dimensional seepage model is established by using the parameters reversely derived to simulate the changing relation between water level and time in multi wells pumping. The dewatering effect of multi wells is analyzed to verify whether the dewatering design is reasonable in order to guide the foundation pit excavation.

Key words:foundation pit dewatering; pumping test; multi wells pumping; seepage model; safety assessment