临近既有桥梁泵站基坑地下水控制方案研究

Study on Groundwater Control Scheme of Foundation Pit Closing to Existing Bridge

长江一级阶地地区排水泵站基坑往往需要采取降水措施来控制地下水的影响;当基坑周边有现状建构筑物时,又需控制降水对周边环境的影响。针对存在的现实问题,文章以武汉长江一级阶地某临近桥梁的泵站基坑为例,综合基坑地质情况和周边环境,采用钻孔灌注桩加内支撑的支护形式,结合TRD工法落底式止水帷幕和坑内疏干降水的地下水控制方案,借助有限元软件分析基坑降水对临近桥梁的变形影响,并与现场监测结果进行对比。结果表明,TRD工法落底式止水帷幕的强度和渗透性均能满足泵站基坑的工程需求,且能减少降水过程中对桥梁水平和竖向沉降的影响,确保基坑周边建构筑物的安全。

The foundation pit of the drainage pump station in the first terrace area of the Yangtze River often requires precipitation measures to control the impact of groundwater;When there are existing buildings around the foundation pit,it is necessary to control the impact of precipitation on the surrounding environment.In response to the existing practical problems,this article takes the foundation pit of a pump station near a bridge on the first terrace of the Yangtze River in Wuhan as an example.Based on the geological conditions of the foundation pit and the surrounding environment,a support form of drilled cast-in-place piles and internal supports is adopted.Combined with the TRD construction method,a bottom type waterproof curtain and a groundwater control scheme for dewatering in the pit are used.Finite element software is used to analyze the deformation effect of foundation pit dewatering on the adjacent bridge,and the results are compared with on-site monitoring.The results show that the strength and permeability of the TRD construction method's bottom type waterproof curtain can meet the engineering requirements of the pump station foundation pit,and can reduce the impact of precipitation on the horizontal and vertical settlement of the bridge,ensuring the safety of the surrounding buildings.