地层空洞影响下地铁盾构隧道衬砌结构响应试验研究  

Experimental study on lining response of metro shield tunnel under the influence of ground cavity

作　　者：管锋 魏度强 雷金山[3] 石钰锋[2,4] 曹成威 GUAN Feng;WEI Duqiang;LEI Jinshan;SHI Yufeng;CAO Chengwei(China Railway Nanchang Bureau Group Co.,Ltd.,Nanchang 330002,China;School of Civil Engineering,East China Jiaotong University,Nanchang 330013,China;School of Civil Engineering,Central South University,Changsha 410075,China;Nanchang Rail Transit Group Co.,Ltd.,Nanchang 330038,China)

机构地区：[1]中国铁路南昌局集团有限公司,江西南昌330002 [2]华东交通大学土木建筑学院,江西南昌330013 [3]中南大学土木工程学院,湖南长沙410075 [4]南昌轨道交通集团有限公司,江西南昌330038

出　　处：《铁道科学与工程学报》2022年第2期461-469,共9页Journal of Railway Science and Engineering

基　　金：江西省自然科学基金资助项目(20192BAB206043);国家地区科学基金资助项目(51768020)。

摘　　要：为探究盾构隧道管片背后空洞对隧道结构的影响,采用模型试验手段,考虑空洞形成过程,分别就无空洞,拱顶、拱腰、拱底背后空洞4种工况下衬砌结构变形、受力、与地层接触压力的响应规律进行研究。研究结果表明:无空洞时,衬砌受到均匀的地层压力,同时地层也提供给衬砌充足的地层反力,管片内力呈“对称式”分布。有空洞时,空洞的存在改变了衬砌与周边地层的接触状态,空洞附近衬砌所受地层抗力消失,受偏压作用衬砌截面发生趋向于空洞处的变形,衬砌结构整体受力状态恶化,内力分布较为复杂,空洞边缘位置处出现应力集中效应。不同空洞位置对隧道结构安全性影响排序为:拱腰>拱顶≥拱底。拱腰背后存在空洞时,该截面弯矩值较无空洞增长约2.78倍,管片外侧受较大拉应力。拱顶、拱底背后存在空洞时,衬砌结构变形及受力趋势较为相似,均表现为空洞所在截面处管片弯矩值较无空洞时显著降低,而两侧临近截面处弯矩值出现增长,原截面弯矩值转由两侧临近截面分担;不同的是,拱顶背后存在空洞时,当空洞尺寸增大至一定值,拱顶两侧均出现反弯点,拱顶弯矩值发生反向,拱顶由原受正弯变为受负弯状态(规定衬砌内侧受拉、外侧受压时为正弯矩),空洞所在截面处弯矩变化率较大,管片易受集中荷载作用。In order to explore the influence of the cavity behind the shield tunnel segment on the tunnel structure,the model test is used to study the response rules of the deformation,stress and contact pressure with the stratum of the lining structure under the four working conditions of no cavity,arch crown,arch waist and cavity behind the arch bottom.The results show that when there is no cavity,the lining is subjected to uniform stratum pressure,and the stratum also provides sufficient stratum reaction force for the lining,and the internal force of the segment is“symmetrical”.When there is a cavity,the existence of the cavity changes the contact state between the lining and the surrounding strata,the formation resistance of the lining near the cavity disappears,the lining section tends to deform at the cavity under the action of bias pressure,the overall stress state of the lining structure deteriorates,the internal force distribution is complex,and the stress concentration effect appears at the edge of the cavity.The influence of different cavity positions on the safety of tunnel structure is as follows:arch waist>arch crown≥arch bottom.When there is a cavity behind the arch waist,the bending moment of this section increases by about 2.78 times compared with that without cavity,and the outer side of the segment is subjected to large tensile stress.When there is a cavity behind the arch crown and arch bottom,the deformation and stress trend of the lining structure are relatively similar,which shows that the segment bending moment value at the section where the cavity is located is significantly lower than that without cavity,while the bending moment value at the adjacent sections on both sides increases,and the bending moment value of the original section is shared by the adjacent sections on both sides;The difference is that when there is a cavity behind the arch crown,when the size of the cavity increases to a certain value,reverse bending points appear on both sides of the arch crown,the bending moment value

关 键 词：衬砌背后空洞 盾构隧道 受力特征 变形规律 接触状态 模型试验 

分 类 号：U45[建筑科学—桥梁与隧道工程]