黄土隧道施工稳定性数值模拟对比研究

以银川至昆明公路某黄土隧道为研究对象,利用有大型有限元软件Midas/GTS建立地层-隧道三维弹塑性有限元模型,对CRD法、CD法以及留核心土等三种不同开挖方式对该隧道稳定性进行了数值模拟分析。隧道围岩的位移、支护结构强度等数值模拟结果表明,核心法开挖引起的拱顶最大沉降0.043m、最大弯矩为21.52KN/m、最大轴力为255.7KN;CD法开挖引起的最大弯矩为22.51KN/m,支护结构最大轴力为518KN;CRD法开挖引起的支护结构最大弯矩为15.274KN/m,最大轴力为253KN;结合三种开挖方案在拱顶、左右拱腰、左右拱脚以及拱底等6个监测点竖向位移对比分析下,采用留核心土法开挖引起的围岩位移场和支护结构内力状态均优于CRD法和CD法,研究成果可为黄土隧道施工开挖方式选择提供参考。

Taking a loess tunnel on the Yinchuan-Kunming highway as the research object,using the large-scale finite element software Midas/GTS to establish a stratum-tunnel three-dimensional elasto-plastic finite element model,three different excavations such as CRD method,CD method and core soil The stability of the tunnel was analyzed by numerical simulation.Numerical simulation results of tunnel surrounding rock displacement and supporting structure strength show that the maximum settlement of the vault caused by core method excavation is 0.043m,the maximum bending moment is 21.52KN/m,and the maximum axial force is 255.7KN;CD method excavation causes The maximum bending moment of the supporting structure is 22.51KN/m,and the maximum axial force of the supporting structure is 518KN;the maximum bending moment of the supporting structure caused by the CRD method is 15.274KN/m,and the maximum axial force is 253KN;Under the comparative analysis of the vertical displacement of the 6 monitoring points,including the vault,the left and right arch waist,the left and right arch feet,and the arch bottom,the surrounding rock displacement field and the internal force state of the supporting structure caused by the excavation of the core soil method are better than those of the CRD method and The CD method,the research results can provide reference for the selection of the construction and excavation method of the loess tunnel.