黄土地层基坑工程近距上跨地铁隧道小变形控制方法研究  

Microdeformation Control Method of a Loess Foundation Pit Closely Crossing Above a Metro Tunnel

作　　者：时炜 郑建国 曹静远[3] 于永堂 梁保真[1] 雷伟 张志毅 SHI Wei;ZHENG Jianguo;CAO Jingyuan;YU Yongtang;LIANG Baozhen;LEI Wei;ZHANG Zhiyi(Shaanxi Construction Engineering Group Co.,Ltd.,Xi′an 710003,Shaanxi,China;China Jikan Research Institute of Engineering Investigations and Design Co.,Ltd.,Xi′an 710021,Shaanxi,China;College of Civil Engineering,Xi′an University of Architecture and Technology,Xi′an 710055,Shaanxi,China;China United Northwest Institute for Engineering Design&Research Co.,Ltd.,Xi′an 710077,Shaanxi,China;Shaanxi Huashan Road and Bridge Group Co.,Ltd.,Xi′an 710016,Shaanxi,China)

机构地区：[1]陕西建工集团股份有限公司,陕西西安710003 [2]机械工业勘察设计研究院有限公司,陕西西安710021 [3]西安建筑科技大学土木工程学院,陕西西安710055 [4]中联西北工程设计研究院有限公司,陕西西安710077 [5]陕西华山路桥集团有限公司,陕西西安710016

出　　处：《隧道建设(中英文)》2025年第2期361-374,共14页Tunnel Construction

基　　金：国家自然科学基金项目(42072302);陕西省秦创原“科学家+工程师”队伍建设项目(2022KXJ-086);陕西省重点研发计划项目(2023-YBSF-499);西安市秦创原“科学家+工程师”队伍建设项目(23KGDW0025-2023)。

摘　　要：为解决黄土地区紧邻地铁盾构隧道施工难度大、支护体系设计复杂、隧道变形控制难等问题,以西安市某与地铁隧道小净距上跨的地道基坑工程为背景,采用考虑土体小应变硬化特性的有限元方法,分析传统分区分块开挖法、“隔离桩+土体加固”法和超前管幕法对地铁隧道变形的控制效果。基于排桩隔离、管幕压制的地铁隧道变形控制思路,提出“管幕+隔离桩”的地铁隧道变形控制新方法,并对新方法施工期和工后期的地铁隧道变形进行监测分析。结果表明:1)新方法将管幕和隔离桩连接,使土体回弹荷载由管幕和桩体自重力、桩土摩擦力共同承担,能够有效限制管幕位移,极大程度地减小隧道上浮;2)相较于传统分区分块开挖法、“隔离桩+土体加固”法和超前管幕法,新方法将地铁隧道最大上浮量分别减少了68%、57%、72%,控制管幕整体上浮效果显著;3)由地铁隧道变形监测数据可知,新方法提出的管幕与隔离桩连接节点设计方法可行,能够约束管幕两端与跨中的位移;4)采用新方法后,隧道实测拱顶最大上浮量为0.8 mm,最大沉降量为1.4 mm,满足隧道的变形控制要求。Projects near metro shield tunnels in loess areas encounter various challenges,including high construction difficulty,complex support system design,and difficulty in controlling tunnel deformation.A case study is conducted to examine a foundation pit situated directly above a metro tunnel in Xi′an,China,and evaluate the effectiveness of different methods for controlling tunnel deformation,including the traditional segmented and block excavation method,the"isolation pile+soil reinforcement"method,and the advance pipe curtain method.The analysis employs a finite element method that considers the small strain hardening property of the soil.Based on the concepts of pile isolation and pipe curtain restraint,a novel"pipe curtain+isolation pile"method is proposed for controlling metro tunnel deformation.The deformation of the metro tunnel during both construction and post-construction periods is monitored and analyzed.The results reveal the following:(1)The proposed method effectively manages pipe curtain displacement by linking the pipe curtain with the isolation pile,significantly reducing tunnel uplift by distributing the rebound load of the soil between the weight of the pipe curtain and the pile-soil friction.(2)Numerical simulations demonstrate that the maximum uplift of the metro tunnel using the proposed method is 68%,57%,and 72%lower than the traditional segmented and block excavation,"isolation pile+soil reinforcement",and advance pipe curtain methods,respectively,thus highlighting the notable uplift control effect of the pipe curtain.(3)Monitoring results reveal that the connection node design of the pipe curtain and isolation pile,based on the proposed method,is effective in constraining displacement at both ends and the mid-span of the pipe curtain.(4)The measured maximum uplift of the tunnel crown and the maximum settlement of the tunnel are 0.8 and 1.4 mm,respectively,both complying with relevant deformation control standards.

关 键 词：基坑工程 隧道变形 变形控制 管幕 隔离桩 

分 类 号：U45[建筑科学—桥梁与隧道工程]