双隧道结构及稳定性开挖影响因素的数值研究及敏感性分析

Numerical Study and Sensitivity Analysis of Influencing Factors of Double Tunnel Structure and Stability Excavation

双隧道的设计、开挖和建设一直以来都是国内外学者研究的重点话题,影响双隧道的影响因素很多,每一种因素都有可能导致隧道的开挖出现不可预见的问题。因此采用室内岩石力学试验、FLAC 3D数值模拟以及决策理论等技术手段对常见的影响双隧道稳定性的拱顶曲率、双隧道间距、隧道仰拱曲率、开挖岩层内聚力以及隧道的长度等5种影响因素进行研究分析,并得出影响双隧道开挖时的最敏感因素。结果表明:随着隧道拱顶曲率的增加,其拱顶位移、最大主应力以及最大垂直应力均呈下降趋势,其中部岩柱的最大垂直应力呈上升趋势;双隧道间距以及其他3种影响因素的改变,均会对双隧道的开挖产生各自不同的影响。同时在此基础上,采用决策理论思想构造判断矩阵,对5种影响双隧道开挖的因素进行了敏感性分析,并根据最大隶属度原则确定了拱顶曲率的设计为影响双隧道稳定性的最敏感因素。研究结果为今后双隧道的设计、开挖、科研以及检测方面提供了科学依据。

The design,excavation,and construction of double tunnels have always been a key topic of research for scholars at home and abroad.There are many factors that affect double tunnels,and each factor may lead to unforeseeable problems in tunnel excavation.Therefore,this article uses indoor rock mechanics experiments,FLAC 3D numerical simulation,and decision theory to study and analyze five common influencing factors on the stability of double tunnels,including arch curvature,double tunnel spacing,tunnel arch curvature,excavation rock cohesion,and tunnel length.The most sensitive factors affecting the excavation of double tunnels are identified.The research results show that as the curvature of the tunnel arch increases,its arch displacement,maximum principal stress,and maximum vertical stress all show a downward trend,while the maximum vertical stress of the central rock column shows an upward trend;The changes in the spacing between double tunnels and the other three influencing factors will have different impacts on the excavation of double tunnels.On this basis,a judgment matrix was constructed using decision theory,and sensitivity analysis was conducted on five factors that affect the excavation of double tunnels.Based on the principle of maximum membership degree,the design of arch curvature was determined as the most sensitive factor affecting the stability of double tunnels.The research results provide scientific basis for the design,excavation,scientific research,and testing of double tunnels in the future.