隧道锚开挖及承载对既有隧道的变形影响分析  

Analysis Method for Deformation of Existing Tunnel Induced by Tunnel Anchor Excavation and Support

作　　者：周捷[1] 席锦州[1] 李海清 于丽[2] 唐浪洲 ZHOU Jie;XI Jinzhou;LI Haiqing;YU Li;TANG Langzhou(Survey and Design Company of Sichuan Road&Bridge(Group)Co.,Ltd.,Chengdu 610041;School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031)

机构地区：[1]四川公路桥梁建设集团有限公司勘察设计分公司,成都610041 [2]西南交通大学土木工程学院,成都610031

出　　处：《现代隧道技术》2023年第6期120-129,共10页Modern Tunnelling Technology

基　　金：四川省交通运输科技项目(2021-ZL-09).

摘　　要：为评估隧道锚开挖及承载对下方既有隧道安全性的影响,采用弹性地基梁理论建立既有隧道在隧道锚开挖及承载影响下的变形计算模型,基于Mindlin公式分别给出隧道锚开挖及承载影响下的附加荷载计算方法,提出既有隧道竖向隆起变形安全性控制标准为12 mm。以四川沿江高速宁巧隧道-隧道锚体系为例,分析既有隧道在隧道锚开挖及承载影响下的变形特征,研究表明:既有隧道变形呈“凸”形,最大变形量位于锚塞体正下方附近,且随着与锚塞体距离的增大,隧道变形逐渐减小,最终收敛;既有隧道变形量随着围岩等级的降低及隧道-隧道锚间距的减小而增大;Ⅲ、Ⅳ级围岩条件下,隧道整体处于安全状态;Ⅴ级围岩条件下,隧道变形量在隧道锚开挖过程中已超过控制值,需要采取围岩加固、结构加强等工程措施。In order to assess how tunnel anchor excavation and support will impact the safety of the existing tunnel below,the calculation model for deformation of existing tunnel induced by tunnel anchor excavation and support has been created for the first time by using the theory of beam on elastic foundation,the method for calculating the addi⁃tional load under the effect of tunnel anchor excavation and support has been devised based on the Mindlin formula,and it is established that the control standard for deformation safety of existing tunnel is 12 mm.By taking the Ningqiao Tunnel-tunnel anchor system of the Yanjiang Expressway in Sichuan as an example,the deformation characteristics of existing tunnel under the effect of tunnel anchor excavation and support have been analyzed.According to the study,the existing tunnel has convex shaped deformation,the maximum deformation happens right below the anchor plug,and the tunnel deformation gradually decreases as the distance of anchor plug increases until the convergence point.The deformation of existing tunnel increases as the surrounding rock grade decreases and the distance between tunnel and tunnel anchor decreases.With ClassesⅢandⅣsurrounding rocks,the tunnel is generally in safe state.With ClassⅤsurrounding rock,the tunnel deformation exceeds the control value during tunnel anchor excavation,so certain engineering measures are required,such as surrounding rock reinforcement and structure strengthening.

关 键 词：既有隧道 隧道锚开挖 锚塞体 变形量 

分 类 号：U452[建筑科学—桥梁与隧道工程]