天津地铁某车站基坑开挖前降水试验研究

Research on the Dewatering Test before Excavation of A Foundation Pit in A Tianjin Metro Station

为了验证基坑围护结构的隔水能力,预判降水施工对周边环境的影响,通过天津地铁某车站基坑开挖之前的降水试验,明确造成潜水层和第一承压水层水位下降的主要原因;对该车站基坑地下连续墙水平位移、地表沉降、附近建筑物沉降情况进行了分析,认为提高地下连续墙施工质量和避免一次性降水深度过大能有效控制降水对周边环境的影响。

In order to verify the water-proof capacity of the envelope structure,and predict the impact of dewatering con-struction on the surrounding environment.Through the dewatering test performed before the excavation of a foundation pit in a station of Tianjin Metro,the paper clarifies the main reason for the lowered water levels of the phreatic aquifer and the first confined aquifer,analyzes the horizontal displacement of the diaphragm wall,ground subsidence and subsidence of nearby buildings in the excavation of the station.It is considered that improving the construction quality of the diaphragm wall and avoiding excessive dewatering depth at one time can effectively control the influence of dewatering on the surrounding environment.