摘要
目的:为避免地铁车站修建时征地拆迁导致的巨额赔偿及工期延误,需研究分析建筑物下超大断面矿山法横向扩挖地铁车站的变形规律和受力特性。方法:依托成都地铁13号线新南门站矿山法横向扩挖盾构井工程,运用MIDAS GTS有限元程序分析研究矿山法横向拓展车站期间周边建筑物及扩挖结构的变形规律及受力特征,并针对性地提出安全控制措施。结果及结论:导洞开挖支护作业引起的建筑物沉降量最大,约占总沉降值的55%;拆除临时支撑浇筑二次衬砌和破除洞口临时立柱引起的建筑物沉降量分别占总沉降值的28%和17%,且其沉降变化速率较快;建筑物基础间最大差异沉降值为1.6 mm,满足0.2%l(l为相邻基础中心距离)控制值要求;最大倾斜值为0.00013,远小于0.003的整体倾斜控制值。地面沉降呈“双漏斗”状,沉降最大值为8.5 mm,沉降槽宽度为明挖车站结构外延30.0 m;掌子面水平变形呈现出中间大、四周小的楔形分布规律,并关于掌子面中心线基本对称;二次衬砌结构弯矩极值位于洞口周边及板墙交接处,应力集中现象显著。
Objective:To avoid substantial compensation and delays in construction caused by land acquisition and demolition during the construction of metro stations,it is essential to investigate and analyze the deformation law and force characteristics of metro station with laterally expanded super-large profile using the mining method excavating beneath buildings.Method:Leveraging the mining method lateral expansion shield shaft engineering at Xinnanmen Station on Chengdu Metro Line 13,the MIDAS GTS finite element method is employed to analyze and study the deformation law and force characteristics of surrounding structures and excavation structures during the lateral expansion of the station.Moreover,targeted safety control measures are put forward.Result&Conclusion:The building settlement caused by the excavation of pilot tunnel and support operation is the most significant,accounting for approximately 55%of the total settlement.The removal of temporary support,casting of secondary lining,and removal of temporary pillars at the tunnel entrance caused building settlements of 28%and 17%of the total settlement,respectively,with relatively rapid settlement change rates.The maximum differential settlement between building foundations is 1.6 mm,meeting the control value requirements of 0.2%l(where I is the center distance between adjacent foundations).The maximum inclination is 0.00013,significantly lower than the overall inclination control value of 0.003.Land subsidence exhibited a′double funnel′shape,with a maximum subsidence value of 8.5 mm and a trough width extending 30.0 m beyond the open-excavated station structure.The horizontal deformation of the working face presents a wedge-shaped distribution with a large deformation in the middle and smaller ones around it,exhibiting basic symmetry along the centerline of the working face.The maximum bending moment of the secondary lining structure occurs around the tunnel entrance and at slab-wall junction,demonstrating a significant stress concentration phenomenon.
作者
胡瑞青
HU Ruiqing(China Railway First Survey and Design Institute Group Co.,Ltd.,710043,Xi’an,China)
出处
《城市轨道交通研究》
北大核心
2023年第12期122-126,共5页
Urban Mass Transit
基金
中铁第一勘察设计院集团有限公司科研开发项目(院科19-52,院科20-21,院科20-53)。
关键词
地铁车站
横向扩挖
变形规律
数值计算
受力特征
metro station
lateral expansion excavation
deformation law
numerical calculation
force characteristics
