PBA法地铁车站施工引起的地表沉降规律研究

Research on Surface Settlement of Subway Station Constructed by PBA Method

以北京市某新建地铁车站为依托,简述了PBA工法施工步骤,对不同施工阶段引起的地表沉降数据进行分析,并与设计控制分解比例进行对比,由此探讨施工引起的地表沉降规律。统计了车站419个测点的最终沉降值,使用Peck公式对车站42个横向监测断面沉降槽曲线进行拟合,并对拟合结果进行了验证,最终得到了横向监测断面最大沉降点与车站结构的位置分布规律。研究结果表明导洞、初支扣拱暗挖施工是引起地表沉降的主要施工工序,最大沉降一般发生在结构中线两侧3 m范围内,在施工中应重点加强结构中部暗挖施工的超前加固与质量控制。

Based on a newly-built subway station in Beijing,this paper briefly described the construction steps of the subway station constructed by PBA method,analyzed the surface settlement data caused by different construction stages,and compared it with the decomposition ratio of design control.From this,the law of surface settlement caused by station construction was discussed.The final settlement values of 419 stations were calculated and the distribution law of accumulated settlement values was found out.In addition,the Peck formula was used to fit the settlement trough curves of 42 transverse monitoring sections in the station,and the accuracy of the fitting results was verified.Finally,the location distribution law of the maximum settlement point of the transverse monitoring section and the station structure was obtained.The results show that the underground excavation of the pilot tunnel and the initial support buckle arch is the main construction procedure that causes the surface settlement,and the maximum surface settlement occurs within 3 m on both sides of the structure centerline.Therefore,the leading consolidation effects and the quality control measures for the tunnel excavation in the middle of the structure should be strengthened.