新建隧道小净距斜下穿既有隧道变形多因素分析  

Multi-factor Deformation Analysis for Newly-built Tunnel Obliquely Under-passing Existing Tunnels by Small Clearance

作　　者：赵耀[1] 黄长鑫 张青[1] 邵靖淇 高子明 张连震 陈健 王宠 于雷 ZHAO Yao;HUANG Changxin;ZHANG Qing;SHAO Jingqi;GAO Ziming;ZHANG Lianzhen;CHEN Jian;WANG Chong;YU Lei(Kunming Railway Construction Company of China Railway No.8 Engineering Group Co.Ltd.,650299,Kunming,China;School of Civil Engineering,Shandong University,250061,Jinan,China;College of Pipeline and Civil Engineering,China University of Petroleum,266580,Qingdao,China)

机构地区：[1]中铁八局集团昆明铁路建设有限公司,昆明650299 [2]山东大学土建与水利学院,济南250061 [3]中国石油大学(华东)储运与建筑工程学院,青岛266580

出　　处：《城市轨道交通研究》2025年第3期58-63,共6页Urban Mass Transit

基　　金：国家重点研发计划项目(2020YFB1600500);国家自然科学基金面上项目(52179120,52171267);江西省交通厅重点项目(2024ZG012)。

摘　　要：[目的]在极小净空间条件下实施新建隧道下穿既有隧道作业时,新建隧道极易遭遇变形、塌方等安全风险,进而威胁既有线路的正常运营。因此,有必要对新建隧道小净距斜下穿既有隧道变形因素进行分析。[方法]基于青岛地铁8号线青岛北站—沧口站区间隧道斜下穿既有运营地铁3号线隧道的实际施工案例,采用ABAQUS有限元软件对开挖过程进行数值模拟,深入探讨了开挖工法、开挖进尺及围岩条件三大要素对既有隧道受力变形特性的影响。[结果及结论]相较于全断面法,采用台阶法施工会导致既有隧道的最大竖向位移和水平位移分别增加24%,这充分表明全断面法在控制隧道变形方面具有更优的表现。同时,开挖进尺增大和围岩条件恶化均显著加剧既有隧道位移,进尺从0.5 m增至1.5 m时,竖向位移增加13%,水平位移增加28%,归因于穿越形态、应力释放、重分布及变形约束。围岩等级从Ⅲ级劣化至Ⅴ级,竖向位移增加302%,水平位移增加205%,影响远超开挖工法和进尺。在开挖里程-位移曲线中,工法决定曲线形态,进尺和围岩条件决定位移大小。针对小净距斜下穿工程,建议围岩条件良好时,优先采用全断面法和小进尺施工,以减轻既有隧道应力和变形。[Objective]In construction scenarios involving new tunnel construction under-passing existing tunnels by extremely small clearance,the new tunnels are highly susceptible to deformation,collapse,and other safety risks,thereby threatening the normal operation of existing lines.Therefore,it is necessary to analyze the factors influencing deformation when new tunnels obliquely under-pass existing tunnels by small clear distances.[Method]Based on the actual construction case of Qingdao North Station-Cangkou Station interval on Qingdao Metro Line 8,where the tunnel obliquely passes under the existing operating tunnel on Line 3,the finite element calculation software ABAQUS is employed to numerically simulate the excavation process.The impact of three key factors on the deformation characteristics of the existing tunnel are examined in-depth,including excavation method,excavation step length,and surrounding rock conditions.[Result&Conclusion]Compared to the full-face excavation method,the bench excavation method would increase the maximum vertical displacement and horizontal displacement of existing tunnel by 24%,indicating that the full-face method performs better in controlling tunnel deformation.Meanwhile,the increased excavation step length and deteriorated surrounding rock conditions significantly exacerbate the displacement of the existing tunnels.When the step length increases from 0.5 m to 1.5 m,the vertical displacement will increase by 13%and the horizontal displacement by 28%,attributed to crossing geometry,stress release,redistribution,and deformation constraints.When the surrounding rock grade deteriorates from Grade III to Grade V,the vertical displacement will surge by 302%and horizontal displacement by 205%,causing an influence far exceeding that of the excavation method and step length.In the excavation mileage-displacement curve,the excavation method determines the curve shape,while step length and surrounding rock conditions dictate the displacement magnitude.For small-clearance oblique under-passing

关 键 词：地铁 隧道工程 小净距斜下穿 有限元模拟 隧道变形 

分 类 号：U213.213[交通运输工程—道路与铁道工程]