洞桩法施工对地表沉降影响的数值模拟及实测研究

The Influence of PBA Method Construction on Surface Settlement by Numerical Simulation and Measured Study

以北京地铁6号线西延工程廖公庄站的洞桩法(PBA工法)施工为工程背景,利用FLAC 3D数值模拟软件对车站PBA工法施工过程中引起的地表沉降进行了数值模拟分析,同时选用具有高精度、自动化程度高的精密仪器静力水准实时监测系统进行监测,并把模拟数据与基于静力水准实时监测技术得到的监测数据进行对比分析。研究表明:数值模拟结果和实测数据大体相似,即在车站的整个开挖过程中,地层沉降主要发生在导洞开挖过程,大约占总沉降的71%;在导洞开挖过程中对地表沉降影响最大的阶段是在上导洞开挖阶段,沉降值达到了31mm;扣拱阶段是导致地表沉降加大的另一个重要工序。

Based on the cave-pile method（ PBA method） of West Liao Gong Zhuang station of Beijing Subway Line 6 as practical engineering background,this paper presented the research of FLAC 3 D numerical simulation on surface settlement which was caused by construction of subway station with PBA method. Besides,hydrostatic level,a highly precise and automatic real-time monitoring system,was used to detected,meanwhile,the contrast analysis was given between simulated data and test data instrumented by the real-time hydrostatic leveling system. The research indicated that the numerical simulation results and measured data were broadly similar to each other,namely,the main settlement mainly occurred in the pilot tunnel excavation process accounting for about 71% in the excavation process of the station; One of the biggest impacts on surface subsidence stage was in the upper pilot tunnel excavation period,which the settlement value has arrived at 31 mm; Buckle arch stage was another important step to speed up the surface subsidence.