富水软弱地层地铁宽大基坑变形分析及措施研究

Deformation Analysis and Mitigation of a Large Foundation Excavation for the Metro Station in a Saturated Soft Stratum

依托苏州3号线华山路站基坑工程,结合工程地质、基坑围护结构设计及施工监测情况,对基坑设计进行多方案比选,分析总结了宽大基坑不同开挖阶段的监测数据及变形规律。分析认为:富水软弱地层地铁宽大基坑采用混凝土支撑支护变形不易控制,立柱隆起及混凝土支撑轴力较大;施工中应优化土方开挖方式及加快支撑架设速度,及时浇筑早强垫层及底板以便控制基坑变形;设计中应考虑立柱隆起及混凝土支撑轴力较大的不利影响,采取相应的针对性措施。

This paper presents a case history of foundation excavation for Huashan Road Station of Suzhou Metro Line No.3.The foundation excavation supporting design methods were selected and optimized based on the site engineering geology conditions,supporting structure performance and construction technique.Different stages of this wide and large sized deep excavation construction were monitored,and the data were analyzed.The conclusions can be made as follow:For deep excavation supporting for a wide metro station excavation in saturated soils,the concrete raker with horizontal waler supporting method have the following characteristics:difficult in the deflection control,solder pile heaving and large axial stress in the reinforced concrete rakers.During the construction,the earth removal pattern should be optimized and the installation of raker support should be accelerated.The bottom concrete slab of the foundation should be poured immediately after the completion of the excavation so that the supporting system deformation can be controlled.In the design the heave of the solder pile and the larger axial stress in the concrete raker.