上海某深基坑群井抽水试验参数分析

Parametric Analysis on Group-well Pumping Test of a Deep Foundation Pit in Shanghai

摘要:

传统的抽水试验主要为单井抽水试验，获得相关水文地质参数不够精确，同时又存在较大的误差。以上海地区某深基坑工程为例，该基坑最大开挖深度为25.8 m，⑦1层粉砂夹粉质粘土与⑦2层粉砂两者相互贯通，针对⑦层土进行群井抽水试验，对试验所得数据进行拟合分析，得到导水系数平均值为T=115 m2/d，水平渗透系数平均值Kh=4.61 m/d，Kv=0.155×4.61 m/d=0.71 m/d，储水系数S=1.31×10-3，为基坑工程降水施工提供重要的参考依据。

Abstract:

The traditional pumping test is mainly a single-well pumping test. It is not accurate to obtain the relevant hydrogeological parameters, and there are large errors. Taking a deep foundation pit project in Shanghai as an example, the maximum excavation depth of the foundation pit is 25.8 m. And the two layers of ⑦1 silty sand with silty clay and ⑦2 silty sand are interconnected. The group-well pumping test for ⑦ layer soil is carried out. The tested data are fitted and analyzed. The average value of the water conductivity coefficient is T=115 m2/D, the average value of the horizontal permeability coefficient is Kh=4.61 m/d and kv=0.155×4.61 m/d=0.71 m/d, and the water storage coefficient is S=1.31×10-3 , which provide the important reference for dewatering construction of foundation pit engineering.