基坑开挖卸荷对侧方隧道的影响研究——以南京市某地铁车站基坑开挖为例  

A Numerical Simulation Study on the Influence of Foundation Pit Excavation Unloading on Lateral Tunnel:A Metro Station Foundation Pit Excavation in Nanjing as an Example

作　　者：丰土根[1,2] 王湛铭 张箭 彭朋 孙津津 王威 李明东 FENG Tugen;WANG Zhanming;ZHANG Jian;PENG Peng;SUN Jinjin;WANG Wei;LI Mingdong(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210098,China;School of Civil Engineering and Surveying and Mapping Engineering,Jiangxi University of Science and Technology,Ganzhou 341000,China;China Power Construction Railway Construction Investment Group Co.,Ltd,Beijing 100070,China;Beijing Urban Construction Zhongnan Civil Engineering Group Co.,Ltd,Beijing 100023,China;School of Civil and Architectural Engineering,East China University of Technology,Nanchang 330013,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210098 [2]江西理工大学土木与测绘工程学院,江西赣州341000 [3]中电建铁路建设投资集团有限公司,北京100070 [4]北京城建中南土木工程集团有限公司,北京100023 [5]东华理工大学土木与建筑工程学院,江西南昌330013

出　　处：《东华理工大学学报（自然科学版）》2024年第5期482-494,共13页Journal of East China University of Technology(Natural Science)

基　　金：国家自然科学基金面上项目(52378336);江西省重大科技研发专项(20232ACG01004)。

摘　　要：为研究基坑土体开挖卸荷对围护结构、墙后土体变形以及隧道的影响,针对南京地区地铁车站基坑开挖对侧方既有隧道的影响进行研究,借助有限元软件ABAQUS建立二维隧道-基坑数值模型,重点对隧道水平和竖向位移、隧道结构应力、支护桩水平位移以及基坑周边地表沉降进行分析。研究表明,由于拱顶处混凝土厚度较薄,抵抗变形能力较差,水平位移最大值出现在南侧隧道拱顶位置,基坑开挖过程中,第二和第三层土体开挖对隧道竖向位移影响最大;隧道结构的拉应力整体上随基坑开挖的进展呈现逐渐增加的趋势,第二层土体开挖对隧道结构的拉应力和压应力影响最大;隧道的存在会在一定程度上提高周围土体的刚度,使得土体变形减小,支护桩水平位移曲线呈现“两端小,中间大”,受隧道的“遮挡效应”影响,近隧道水平位移小于远隧道侧;基坑开挖过程中地表沉降变形形态呈“凹槽型”,隧道结构的存在能有效控制近隧道侧地表变形。To study the impact of excavation and unloading of the foundation pit on the enclosing structure,the deformation of the soil behind the wall,and the tunnel,the impact of the foundation pit excavation at the metro station in Nanjing on the adjacent existing tunnel is investigated.A two-dimensional numerical model of the tunnel-pit interaction was established using ABAQUS software,focusing on the analysis of tunnel horizontal and vertical displacements,structural stress of the tunnel,horizontal displacements of the supporting piles,and settlement of the ground surface around the foundation pit.It shows that the maximum horizontal displacement occurs at the south tunnel vault due to the thin concrete thickness and poor resistance to deformation at this location.The excavation of the second and third layers of soil has the greatest influence on the vertical displacement of the tunnel during the foundation pit excavation process.The tensile stress of the tunnel structure exhibits a gradual increasing trend with the excavation of the foundation pit,with the second layer of soil having the greatest influence on both the tensile and compressive stress of the tunnel structure.The tunnel increases the stiffness of the surrounding soil to a certain extent,reducing soil deformation.The horizontal displacement curve of the supporting piles shows a pattern of“small at both ends,large in the middle”due to the“shielding effect”of the tunnel,with horizontal displacement near the tunnel being smaller than that further away.During the excavation of the foundation pit,the deformation pattern of surface settlement is“notch-type”,and the presence of the tunnel structure effectively inhibits surface deformation on the near-tunnel side.

关 键 词：基坑开挖 隧道变形分析 数值模拟 地层沉降 隧道结构应力 

分 类 号：U231.4[交通运输工程—道路与铁道工程]