回填土大跨超浅埋地铁隧道开挖稳定性分析  

Analysis of Excavation Stability of Backfill Soil Large Span Super Shallow Buried Metro Tunnel

作　　者：鲍先凯[1] 王舒锐 李文辉 张武 吴宁 BAO Xian-kai;WANG Shu-rui;LI Wen-hui;ZHANG Wu;WU Ning(School of Civil Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China;The 3rd Engineering Co., Ltd. of China Railway 12th Bureau Group, Taiyuan 030024, China)

机构地区：[1]内蒙古科技大学土木工程学院,包头014010 [2]中铁十二局集团第三工程有限公司,太原030024

出　　处：《科学技术与工程》2022年第8期3342-3348,共7页Science Technology and Engineering

基　　金：内蒙古自治区自然科学基金(2020LH05018);内蒙古科技大学建研所开放基金(JYSJJ-2021M19)。

摘　　要：贵阳市地铁1号线望新区间隧道地质环境复杂,位于回填区,地下水丰富,埋深浅。针对此类环境,首次将三台阶七步开挖法引进到地铁区间隧道施工中,通过对隧道开挖稳定性的关键因素分析及施工方法的数值模拟,结合现场实测,研究了回填土大跨超浅埋地铁隧道开挖稳定性。结果表明:超浅埋开挖,回填土地层承载拱难以形成;开挖过程中拱顶、拱脚及仰拱部位产生拉应力,拱腰部位出现应力集中,为压应力区;地表及拱顶沉降变形主要受上台阶导洞开挖的影响,中、下台阶导洞的影响次之,核心土开挖影响较小;核心土及仰拱开挖对拱底围岩变形产生较大影响;因此在开挖过程中要对上述位置进行重点监测,可为今后类似工程提供借鉴。The geological environment of Guiyang Metro Line 1 Wangxin Tunnel is complex because it is located in the backfill area with rich groundwater and shallow depth.The three-bench seven-step excavation method was firstly introduced into the construction of metro tunnel to conquer this kind of environment.The excavation stability of long-span ultra-shallow buried subway tunnel with backfill soil was studied through the analysis of key factors affecting the stability of tunnel excavation and the numerical simulation of construction method,combined with the field measurement.The results show that form load-bearing arch in backfill stratum during ultra-shallow excavation is difficult.During the excavation,tensile stress occurs at the vault,arch foot and invert,and a compressive stress concentration zone occurs at the arch waist.The subsidence deformation of ground surface and vault is mainly affected by the excavation of upper-step guide tunnel,which followed by the excavation of middle and lower step guide tunnel,and the excavation of core soil has little influence.Core soil and invert excavation have a greater influence on the deformation of surrounding rock at the arch bottom.Therefore,the above positions should be monitored during the excavation process,which will provide reference for similar projects in the future.

关 键 词：大跨超浅埋隧道 三台阶七步开挖法 回填土 稳定性 

分 类 号：U457.2[建筑科学—桥梁与隧道工程]