基于动荷载的交叠盾构隧道两阶段安全分析  

Two-Stage Safety Analysis of Overlapped Shield Tunnels Based on Dynamic Loads

作　　者：冯义[1] FENG Yi(China Railway First Survey and Design Institute Group Co.,Ltd.,Xi′an 710043)

机构地区：[1]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《现代隧道技术》2021年第4期109-116,共8页Modern Tunnelling Technology

基　　金：中铁第一勘察设计院科研开发项目基金(院科20-56).

摘　　要：为研究富水砂层地铁隧道在动荷载作用下施工和运营阶段共同作用的安全问题,以南京地铁5号线下穿既有地铁1号线为例,建立交叠隧道数值模型,分别对两阶段共同作用下的地铁沉降及运营期疲劳寿命进行了探讨和分析。结果表明:(1)下穿施工期间隧道沉降最大值为7.5 mm,采用洞内微扰动注浆+内张钢圈的设计方案可有效控制本阶段隧道变形;(2)5号线运营后,1号线隧底第1年沉降占比最大,约占10年期总沉降的65%,后沉降变化速率逐步收敛;(3)新建地铁5号线通过壁后注浆可大幅降低1号线长期运营沉降,确保1号线长期运营安全;(4)交叠处管片疲劳寿命最小,远离交叠区疲劳寿命越来越大,本工程整体性能满足结构设计使用年限要求。In order to study the safety of subway tunnels in water-rich sandy strata under the interaction of dynamic load during the construction and operation phases,taking the Nanjing Metro Line 5 passing under the existing Line 1 as the example,this paper establishes a numerical model of the overlapped tunnels to investigate and analyze the subway settlement and the fatigue life under the interaction of the two phases.The results show that:(1)the maxi⁃mum tunnel settlement during the under-passing construction is 7.5 mm,and the design scheme of micro-disturbed grouting+full-ring steel plate in the tunnel could effectively control the tunnel deformation during this stage;(2)af⁃ter operation of Line 5,the proportion of settlement at the Line 1 tunnel base in the first year is the largest,account⁃ing for about 65%of the total settlement in the 10-year period,after which the settlement rate gradually converges;(3)through backfilling grouting in new Metro Line 5 it can significantly reduce the long-term operational settlement of Line 1,ensuring the long-term operational safety of Line 1;(4)the fatigue life of the segments at the overlap is the shortest,while the fatigue life of the segments far away from the overlap area is longer,and the overall performance of the project meets the requirements for the design service life of the structure.

关 键 词：运营地铁 交叠隧道 富水砂层 沉降计算 疲劳寿命 

分 类 号：U231[交通运输工程—道路与铁道工程]