软岩大变形隧道支护拆换力学与时空变形行为研究  

Study on Mechanical Behavior and Spatio-Temporal Deformation during Support Replacement in Soft Rock Large Deformation Tunnels

作　　者：浣宇翔 田礼勇 杨文波[1] 李昊豫 刘勇 唐浩 姚超凡[1] HUAN Yuxiang;TIAN Liyong;YANG Wenbo;LI Haoyu;LIU Yong;TANG Hao;YAO Chaofan(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031;Sichuan Mianjiu Expressway Co.,Ltd.,Chengdu 610041;Sichuan Expressway Construction and Development Group Co.,Ltd.,Chengdu 610047)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,成都610031 [2]四川绵九高速公路有限责任公司,成都610041 [3]四川高速公路建设开发集团有限公司,成都610047

出　　处：《现代隧道技术》2024年第3期96-107,共12页Modern Tunnelling Technology

摘　　要：针对九绵高速软岩大变形隧道非仰拱部分支护失效所面临的拆换问题,结合现场监测与数值模拟方法,探究支护拆换时的力学行为与时空变形规律及其作用机制。结果表明:(1)研究条件下,靠近非拆换段的新支护受力小,远离非拆换段的新支护受力大;离非拆换段距离相同的新支护,先拆换的受力大,后拆换的受力小。(2)支护拆换工作面位置对新作初期支护受力的影响大于对新作二次衬砌的影响,新作初期支护-二次衬砌应力分担比例与拆换引起的围岩松弛应力呈正相关,改善围岩物理力学参数后进行支护拆换是解决软岩大变形的有效措施。(3)距离非拆换段前后1D(D为隧道等效直径)范围内结构的位移受支护拆换影响小,拆换段中间部分的位移基本相同且比两端大。(4)对于软岩等岩性较差的隧道,拆换时应至少在拆换位置前后1D范围内施加必要的临时保护;拆换前的注浆能起到施工预加固的作用,通过“坏-注-换-抗”的过程,能有效抑制软岩流变效应。In view of the support replacement problem induced by support failure(exclusive of invert arch)in the soft rock large deformation tunnel on Jiuzhaigou-Mianyang Expressway,this study explores the mechanical behavior and spatio-temporal deformation characteristics during support replacement through field monitoring and numerical simulation methods.The results show that:(1)Under the research conditions,the new support near the non-replacement section bears less load,while the new support further away the non-replacement section bears more load.Among the new supports at the same distance from the non-replacement section,the one replaced earlier bears more load,and the one replaced later bears less load.(2)The position of the support replacement working face has a greater impact on the load of the new initial support than on the secondary lining,and the proportion of stress sharing between the new initial support and the secondary lining is positively correlated with the relaxation stress caused by the replacement.Conducting support replacement after improving the physical and mechanical parameters of surrounding rocks is an effective measure to solve the large deformation problem in soft rocks.(3)The displacement of the structure within 1D(D is the equivalent diameter of the tunnel)in front of and behind the non-replacement section is less affected by the support replacement,and the displacement in the middle part of the replacement section is basically the same and larger than that at both ends.(4)For tunnels with poor rock types such as soft rocks,necessary temporary protection should be applied within a range of at least 1D in front of and behind the replacement position.Grouting before replacement can play a role in pre-reinforcement,and the process of"failure-grouting-replacement-resistance"can effectively suppress the rheological effect of soft rocks.

关 键 词：软岩大变形 支护拆换 现场监测 力学行为 时空变形 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]