城市道路穿河深基槽变形监测分析

Monitoring and Analysis of Deformation of a Deep Foundation Pit across the River in the Urban Road Engineering

摘要: 本文以北京市广渠路东延工程穿越北运河段为工程背景，该段沿线地层主要为黏性土、粉土与砂土互层沉积为主，地下分布多层承压水，地下水位埋深约为4 m。该段道路以隧道形式通过北运河，施工为围堰明挖方式进行，最大开挖深度22 m；深基槽采用地下连续墙加五道横支撑进行支护。论文首先按照设计工况，通过理论技术分析了地下连续墙的结构变形和内力变化；然后对基坑施工过程中基坑支护结构和周围土体变形进行了监测，对比分析深基槽整个降水开挖过程的监测数据，发现地连墙实际变形值大于理论计算值，最大形变位置约在16米深度；结合每个开挖阶段周围地表沉降、周围建筑(运通桥)变形监测数据，系统剖析了越河深基槽降水开挖对支护结构、周围建筑物的影响，结果表明基坑降水开挖对运通桥桥桩产生了影响，但是变形值小于控制值，运通桥基本稳定。

Abstract: This paper takes a deep foundation pit project of Guangqu Road in Tongzhou District of Beijing as the background. The recent sediments and Quaternary sediments along the project section are mainly formed by the alluvium of the ancient Chaobaihe River. The strata along the line are mainly clay, silt and sand interbeded deposits. Through the monitoring of the whole precipitation excavation process of the deep foundation groove, the deformation and internal force change of the retaining structure under the working condition are calculated theoretically. Combined with the analysis of the actual monitoring data of the surrounding surface settlement, the deformation of the surrounding building (Yuntong Bridge), the deformation of the underground continuous wall and the settlement of the column inside the grooves, the influence of precipitation excavation on the supporting structure, the surrounding buildings and the surrounding land subsidence in the deep foundation trough across the river are systematically analyzed. Compared with the measured data, it is found that the actual deformation value is larger than the theoretical calculation value.