地铁车站洞桩法开挖变形规律分析  

Deformation laws of subway station excavation by PBA method

作　　者：韩健勇[1] 赵文[1] 关永平[1] 张春文[1] 

机构地区：[1]东北大学资源与土木工程学院,沈阳110819

出　　处：《应用力学学报》2015年第4期623-629,706-707,共7页Chinese Journal of Applied Mechanics

基　　金：国家"十二五"科技支撑计划项目(2012BAK24B01)

摘　　要：针对采用洞桩法施工的沈阳地铁青年大街站,采用MIDAS/GTS有限元数值模拟软件对车站主体结构进行模拟,并将模拟结果与监测数据进行对比,分析和总结了采用洞桩法动态开挖过程中地层以及支护结构的位移变形规律。计算分析结果表明:导洞开挖以及扣拱施工阶段为洞桩法施工的关键阶段,是控制和分析的重点;导洞的群洞效应会对土体变形产生叠加,上导洞和下导洞开挖引起的地表沉降分别为27.1mm和16.8mm,上导洞开挖引起的地表沉降约为下导洞的1.6倍;拱顶沉降主要发生在导洞开挖支护阶段,下导洞的开挖会对上导洞拱顶沉降产生一定程度的影响;边桩水平位移在扣拱施作至中板完成前增长显著,为水平位移最大值的59.5%,该阶段是控制边桩水平位移的关键阶段;在砂土层中采用洞桩法开挖时地铁车站地层损失率相对较小,为0.31%。A subway station in Shenyang is modeled by Pile-Beam-Arch(PBA) method and the main structure of station is simulated by the finite element numerical simulation software MIDAS/GTS. Simulation results are compared with the measured data. Deformation laws of soil and supporting structures during dynamic excavation process are analyzed and summarized by PBA method. Simulation results show that excavation of pilot tunnels and construction of supporting arches are key parts to be analyzed and controlled. Superposition of soildeformation is caused by multi-carven effect. The ground settlement of top and bottom pilot tunnels by excavation is 27.1mm and 16.8mm, respectively. The ground settlement of top pilot tunnels is 1.6 times of that of bottom pilot tunnels, so ground settlement is significantly influenced by excavation of top pilot tunnels. Arch crown settlement mainly occurs in the stage of excavation and supporting of pilot tunnels. Arch crown settlement of top pilot tunnels is affected by bottom pilot tunnels to a certain degree. The horizontal displacement in side-pile increases significantly between the stage of construction of supporting arches and the middle plate finished. The horizontal displacement is 59.5% of the maximum value in this stage. So this is the key stage to control the horizontal displacement of side-pile. Ground loss ratio of subway station excavation by PBA method in sand layer is 0.31%, which is relatively small.

关 键 词：洞桩法 数值模拟 地表沉降 水平位移 导洞开挖 

分 类 号：U231.3[交通运输工程—道路与铁道工程]