膨胀性软岩隧道支护结构受力特性及缓释方法  

Mechanical characteristics and force slow-release method of support structure of expansive soft rock tunnels

作　　者：左清军[1,2] 李心怡 赵先强 李攀 朱盛 韩丙孝 ZUO Qingjun;LI Xinyi;ZHAO Xianqiang;LI Pan;ZHU Sheng;HAN Bingxiao(National Field Observation and Research Station of Landslides in Three Gorges Reservoir Area of Yangtze River,China Three Gorges University,Yichang,Hubei 443002,China;College of Civil Engineering and Architecture,China Three Gorges University,Yichang,Hubei 443002,China;China Construction Fifth Engineering Division Corp.,Ltd.,Changsha,Hunan 410000,China;Faculty of Engineering,China University of Geosciences,Wuhan,Hubei 430074,China)

机构地区：[1]三峡大学湖北长江三峡滑坡国家野外科学观测研究站,湖北宜昌443002 [2]三峡大学土木与建筑学院,湖北宜昌443002 [3]中国建筑第五工程局有限公司,湖南长沙410000 [4]中国地质大学(武汉)工程学院,湖北武汉430074

出　　处：《岩石力学与工程学报》2023年第9期2190-2202,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(42172303,41402259)。

摘　　要：隧道工程中因软岩的膨胀性而诱发的隧道支护结构失稳现象十分普遍。以膨胀性软岩导致隧道围岩结构非均匀受力为出发点,研究膨胀性软岩隧道支护结构的受力特性,试图建立一种膨胀性软岩隧道支护结构受力缓释方法。在初期支护与二次衬砌之间植入团粒膨润土作为缓冲层,开展室内缩尺物理模型试验。通过MIDAS GTS NX软件建立三维数值模型,对比分析加入缓冲层前、后的膨胀性软岩隧道支护结构的受力特性。根据隧道力学理论推导构建膨胀性软岩隧道支护结构受力缓释模型,得到缓释系数表达式,据此验证膨胀性软岩隧道支护结构受力缓释方法的实用性。研究结果表明:加入缓冲层后,支护结构的变形及围岩膨胀力较加入前明显变小,变形均呈拱顶下沉、拱底向上隆起、拱腰向内收敛的特征;缓冲层通过对抗、弱化、传递以减小作用于支护结构上的围岩膨胀力,使单一的集中受力体系转变为均布荷载体系;通过缓释模型计算得出缓释系数为30%~50%,表明在初期支护与二次衬砌之间植入团粒膨润土作为缓冲层可以起到缓释膨胀力的作用,可为解决软岩隧道膨胀问题提供参考。The phenomenon of supporting structure cracking due to the expansive soft rock is common in tunnel engineering.Taking the non-uniform stress of tunnel surrounding rock structure caused by expansive soft rock as the starting point,the stress characteristics of the supporting structure of expansive soft rock tunnels are studied,and a swelling force release method of expansive soft rock tunnel supporting structure is established.The granular bentonite is implanted between the primary support and the secondary lining as the buffer layer,and the model test is carried out.The three-dimensional numerical model is established by MIDAS GTS NX software,and the mechanical characteristics of the expansive soft rock tunnel support structure before and after the buffer layer are comparatively analyzed.According to the tunnel mechanics theory,the swelling force slow-release model of the expansive soft rock tunnel supporting structure is established,and the expression of release coefficient is obtained.The practicability of the slow-release method is verified.The results show that the deformation of the supporting structure and the swelling force of the surrounding rock after adding the buffer layer are significantly smaller than those before adding the buffer layer.The deformation characteristics are characterized by the sinking of the vault,the characteristics of arch bottom upward uplift and the arch waist inward convergence.The buffer layer reduces the swelling force of surrounding rock acting on the supporting structure by resisting,weakening and transferring.Consequently the single concentrated force system is transformed into the uniform load system.The slow-release coefficient calculated by the slow-release model is 30%–50%,indicating that the implantation of granular bentonite as a buffer layer between the initial support and the secondary lining can slow down the swelling force.This research can provide a reference for solving the swelling problem of soft rock tunnels.

关 键 词：隧道工程 膨胀性软岩 膨胀特性 物理模型试验 数值模拟 膨胀力缓释方法 

分 类 号：U45[建筑科学—桥梁与隧道工程]