强风化红砂岩特殊地层深基坑工程地下水综合处理

摘要

以兰州市城市轨道交通1号线一期工程第三系红砂岩特殊地层中深基坑工程地下水处理为例,针对兰州地区红砂岩遇水易软化、崩解、流塑性强、暴露地表易风化等特性,首次提出了“上降下截”的地下水处理设计方案,总结深基坑开挖不同阶段遇到的水文地质问题,形成了在强风化红砂岩特殊地层中“拦、截、堵、排、降”的综合处理措施,以期指引类似地层的设计和施工.%This study considers the third red sandstone special strata of a deep foundation pit groundwater treatment project in the Lanzhou City Metro Line 1 project as an example.The red sandstone in Lanzhou area contains water and exhibits easy softening,disintegration,and plasticity,and its exposed surface presents strong weathering characteristics.First,the groundwater treatment design for the target section for excavation is proposed to study the hydrogeological problems encountered in different stages of the deep foundation pit.Further,comprehensive treatment measures were developed for the weathered red sandstone in the special stratum section,including blocking,intercepting,stopping,discharging and lowering;these measures will guide the groundwater treatment projects in similar strata.