强度折减最短路径在浅埋隧道极限分析的存在性研究  

Research on the Existence of the Shortest Path of Strength Reduction in the Limit Analysis of Shallow Buried Tunnel

作　　者：王薇[1] 邹江海 张学民[1] 张恒文[1] 

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《湖南大学学报（自然科学版）》2017年第9期151-157,173,共8页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51378505)~~

摘　　要：将强度折减最短路径理论,应用于有限元强度折减与极限平衡强度折减分析中,假定黏聚力和内摩擦角按不同折减系数进行强度折减,结合具体算例探讨在双参数强度折减时黏聚力与内摩擦角的合理折减比例,同时考虑隧道埋深与洞跨比值的影响,证明了在浅埋隧道极限分析中强度折减最短路径存在的合理性.研究结果表明:在浅埋隧道强度折减最短路径分析中,随着黏聚力与内摩擦角折减比例λ=Fc/Fφ的增大,黏聚力的折减系数逐渐增大,内摩擦角的折减系数逐渐减小,折减路径长度先减小后增大,两者近似服从抛物线分布,证明存在最短折减路径;同时在强度折减最短路径下,黏聚力的折减幅度要大于内摩擦角,且随着埋深的增加,两者折减幅度逐渐接近.The strength reduction theory of the shortest path was used in the analysis of finite element strength reduction and limit equilibrium strength reduction, the cohesion and internal friction angle were assumed to be reduced by different reduction factor, and the reasonable reduction ratio of cohesion to internal friction angle was discussed in the case of double parameter strength reduction. Considering the influence of the buried depth of the tunnel and tunnel span, the existence of strength reduction of the shortest path in the limit analysis of shallow buried tunnel was proved. The results show that, in the shortest path of the strength reduction of shallow buried tunnel,with the increase of cohesion and internal friction angle reduction ratio, the reduction factor of cohesion increases gradually, the reduction factor of internal friction angle decreases gradually, the reduction path length decreases first and then increases, the reduction ratio and path length approximation follow a parabolic distribution,which proves the existence of the shortest path. In the shortest path of the strength reduction, the reduction range of the cohesion is greater than the internal friction angle, and with the increase of buried depth, the reduction range is gradually approaching.

关 键 词：强度折减 最短路径 有限元法 极限平衡法 合理折减比例 

分 类 号：U457[建筑科学—桥梁与隧道工程]