基坑施工对运营地铁隧道变形影响及分区研究  

Study on the Impact of Foundation Pit Construction on the Deformation of Operating Metro Tunnels and Impact Zoning

作　　者：胡指南[1] 毛洪涛 刘志春[1] 刘占良[2] 孟祥飞 HU Zhinan;MAO Hongtao;LIU Zhichun;LIU Zhanliang;MENG Xiangfei(Key Laboratory of Road and Railway Engineering Safety of Ministry of Education,Shijiazhuang Tiedao University,Shijiazhuang 050043;Shijiazhuang Institute of Railway Technology,Shijiazhuang 050041;Xinjiang Railway Survey and Design Institute Co.,Ltd.,Urumqi 830011)

机构地区：[1]石家庄铁道大学道路与铁道工程安全保障省部共建教育部重点实验室,石家庄050043 [2]石家庄铁路职业技术学院,石家庄050041 [3]新疆铁道勘察设计院有限公司,乌鲁木齐830011

出　　处：《现代隧道技术》2025年第1期66-73,82,共9页Modern Tunnelling Technology

基　　金：国家自然科学基金面上项目(52178392);城市地下空间网络化安全拓建施工技术(2018YFC0808703);河北省自然科学基金优青项目(E2021210025);石家庄铁道大学创新资助项目(YC202421).

摘　　要：依托北京轨道交通某新增换乘通道工程,采用模型试验和数值模拟相结合的方法,研究既有隧道结构由于基坑开挖而产生的竖向位移的变化规律。根据不同近接距离B与覆土埋深h情况下的差异沉降分析既有结构的变形模式,提出了近接系数,并根据其与差异沉降的关系划分了基坑施工的影响分区,确定了4种典型地层下基坑开挖的危险程度。研究结果表明:随着基坑的开挖,隧道结构产生的沉降表现出“缓慢—快速—缓慢”的增长趋势;既有隧道结构由于基坑施工产生的差异沉降随近接距离的增大逐渐减小,随埋深的增大先增加后减小,并逐渐趋近于0;当近接距离与覆土埋深的比值(B/h)一定时,基坑施工引起的既有隧道结构差异沉降也为一个定值;根据近接系数k与差异沉降的关系,认为在依托工程的地层情况下,0.1≤k<5.0时为强影响区,k≥5.0时为弱影响区;并确定了4种典型地层下基坑开挖的危险程度,即软土地层>冲洪积地层>黄土地层>硬岩地层。Based on the new transfer passage project of Beijing Metro,a combined approach of model experiment and numerical simulation was used to study the variation law of vertical displacement of existing tunnel structure caused by foundation pit excavation.The deformation mode of the existing structure was analyzed based on differen⁃tial settlement under different approaching distances(B)and cover depths(h).The concept of an approaching coeffi⁃cient was proposed,and a impact zoning of foundation pit construction was made according to its relationship with differential settlement.Four typical ground conditions were used to assess the risk levels of foundation pit excava⁃tion.The study showed that with the excavation of the foundation pit,the settlement of the tunnel structure exhibits a“slow-fast-slow”growth trend.Differential settlement of the existing tunnel structure caused by foundation pit con⁃struction decreases as the approaching distance increases,and increases then decreases with cover depth,ultimately reaching zero at infinite distance.When the ratio of approaching distance to cover depth(B/h)is constant,the differen⁃tial settlement caused by foundation pit construction is also a constant value.Based on the relationship between the approaching coefficient(k)and differential settlement,it is concluded that when 0.1≤k<5.0,it is a high-impact zone,and when k≥5.0,it is a low-impact zone.The risk levels of foundation pit excavation in four typical ground con⁃ditions were identified as follows:soft soil stratum>alluvial-proluvial stratum>loess stratum>hard rock stratum.

关 键 词：近接基坑 既有隧道 力学特征 差异沉降 影响分区 

分 类 号：U459.3[建筑科学—桥梁与隧道工程]