地铁车站洞桩法暗挖施工对地表沉降及邻近构筑物变形的影响

Surface Settlement and Deformation Law of Existing Structure Influenced by Metro Station Constructed with PBA Method

以北京地铁16号线达官营站为工程依托,对地表变形、管线沉降和建筑物地基变形的监测数据进行分析,得到如下主要结论:地铁车站开挖引起的地层变形划分为初始变形、缓慢变形、急剧变形和变形趋缓4个阶段,各阶段所占比例因工程地质和空间位置等因素而相差各异;地铁车站平行穿越地下管线时,主要引起管线纵向差异沉降,对其横断面受力无明显影响;地层变形主要发生在初支扣拱阶段,初期支护的施作时机和支护刚度的合理确定是地层变形控制的关键。研究成果可为地铁车站穿越既有建(构)筑物的安全施工提供理论依据和技术支撑。

Taking Daguanying Station on Beijing metro Line 16 as the engineering background, the monitoring data of surface deformation, pipeline settlement and building foundation deformation are analyzed, and the following main conclusions are obtained. The ground deformation caused by metro station excavation could be divided into four stages: initial deformation, slow deformation, sharp deformation and slowing down deformation. The proportion of each stage varies due to different engineering geological factors and spatial locations. When the metro station runs parallel beneath the underground pipelines, the difference subsidence in the longitudinal direction of the pipeline will happen, which has no obvious influence on the force of pipeline cross section. The ground deformation mainly occurs during the construction of primary support, reasonable determination of primary support timing and the support stiffness are the keys to control ground deformation. The research results provide a theoretical basis and technical support for the safety construction of metro stations traverses under the existing structures.