设置水平隔水帷幕的基坑降水开挖对周边环境的影响分析

Analysis on the influence of foundation pit dewatering and excavation with horizontal waterproof curtain on surrounding environment

为了研究水平隔水帷幕有效性对基坑降水开挖产生变形的影响,采用三维有限元软件对不同水平隔水帷幕渗透系数条件下基坑降水开挖过程进行模拟,分析了水平隔水帷幕渗透性对周边环境的影响规律。结果表明:1)在全封闭止水条件下,周边地表及高铁高架桥墩沉降随基坑降水开挖的进行而逐渐增大,且计算结果与实测结果较为吻合;2)隔水系统的隔水有效性对基坑降水开挖引起的周边地表和临近高铁高架桥墩沉降影响较大,当水平隔水帷幕渗透系数(k)为1×10^(-7) cm/s和6×10^(-3) cm/s时,周边地表和高铁高架桥墩最大计算沉降分别为63.21,178.66 mm和1.04,31.88 mm;3)全封闭隔水系统将基坑降水开挖引起的临近高铁高架桥墩沉降有效控制在了要求范围内。研究结果可显著提高水平隔水帷幕在基坑工程中的应用效果,并为其相关研究提供经验参考。

In order to study the impact of effectiveness of horizontal waterproof curtain on the deformation of foundation pit dewatering and excavation,the three-dimensional finite element software was used to simulate the dewatering and excavation process of foundation pit under different permeability coefficients of horizontal waterproof curtain,and the influence of the permeability of horizontal waterproof curtain on the surrounding environment was analyzed.The results show that:1)the settlement of surrounding ground surface and high-speed rail viaduct piers gradually increases with the process of dewatering and excavation of foundation pit under the fully enclosed waterproof condition,and the calculated results are in good agreement with the measured results;2)the effectiveness of waterproof system has a great influence on the settlement of surrounding ground and adjacent high-speed rail viaduct piers caused by dewatering and excavation of the foundation pit.When the permeability coefficients(k)of horizontal waterproof curtain are 1×10^(-7) cm/s and 6×10^(-3) cm/s,the maximum settlements of the surrounding ground surface and the viaduct pier are 63.21,178.66 mm and 1.04,31.88 mm respectively;3)the settlement of the adjacent high-speed rail viaduct caused by dewatering and excavation of the foundation pit is effectively controlled within the required range by the fully enclosed waterproof system.The research results significantly improve the application effect of horizontal waterproof curtain in foundation pit engineering and provide empirical reference for the related research.