第三系富水红砂岩地层地铁车站深基坑施工地下水的处理

摘要

According to the adverse impacts of groundwater on excavating the deep foundation pit at the provincial government station of metro line 1 in Lanzhou,the method of groundwater treatment was studied by considering the engineering geological and hydrogeological conditions,the depth of excavation,and the protection requirements of surrounding buildings and environment.The results show that the underground diaphragm wall and tube well dewatering outside the pit could effectively reduce the phreatic water level,because the red sandstone is rich in fissure water,and has serious weathering,weak cementation degree and poor hydro-physical properties,the measures such as catchment drainage and light well point dewatering during the construction was used for treating plenty of water in the pit and bottom plate poured unfavorably caused by fissure water of the red sandstone rising upward,and the 'blocking sand and leading water' method could solve the joint leakage effectively at the corner of underground diaphragm wall.%针对兰州市地铁1号线省政府车站深基坑施工时地下水的不利影响,综合考虑工程地质及水文地质条件、开挖深度、周边建筑物与环境保护要求,对地下水处理方法进行研究.结果表明:采取地下连续墙及坑外管井降水的措施能够有效降低潜水水位;红砂岩中含有丰富的裂隙水,由于红砂岩风化严重、胶结程度弱、水理性质差,施工中分别采用集水明排和轻型井点降水的措施处理红砂岩裂隙水向上冒出所产生的的坑内积水过多和底板无法顺利浇筑的问题;采用"堵砂导水"措施可以较好解决地下连续墙墙角处接缝渗漏问题.