基于FLAC3D的深埋隧道围岩-支护相互作用研究

A Study of Surrounding Rock-Support Interaction of Deep Tunnel:Based on FLAC3D

基于陕西宝汉高速公路石门隧道实际工程,通过FLAC3D建立数值模型进行计算,对考虑蠕变作用的深埋软岩隧道围岩-支护结构相互作用规律以及埋深条件的影响开展研究,得到结论如下:随着蠕变的发展,隧道衬砌变形整体呈现出竖向沉降变形及逐渐被压扁的趋势,衬砌拱顶和拱底的位移更为显著;最小主应力极大值出现在拱腰内侧,随着蠕变时间延长,衬砌的最小主应力极大值逐渐增大,即衬砌的拱腰位置的压应力较大;最大主应力极值分布于拱顶和拱底位置,随蠕变的发展变化不大;随着埋深的增大,竖向变形达到稳定变形阶段后的变化率逐渐增大,同时衬砌的最小主应力极值也逐渐增加,引起衬砌结构上的压应力值增大。

In order to study the interaction law between surrounding rock and support of deep buried tunnel,with creep considered,based on the actual project of Shimen Tunnel of Baohan Expressway in Shaanxi province,this paper establishes a numerical model through FLAC3D for calculation,and studies the interaction law between surrounding rock and support structure of deep buried soft rock tunnel with creep considered and the influence of burial depth conditions.The results are as follows:(1)with the development of creep,the tunnel lining deformation shows a trend of vertical settlement deformation and gradual flattening,and the displacement of lining arch crown and arch bottom is more significant;(2)the maximum value of the minimum principal stress appears at the inner side of the arch waist.With the extension of the creep time,the maximum value of the minimum principal stress of the lining gradually increases,namely,the compressive stress at the arch waist of the lining is larger.The extreme value of the maximum principal stress is distributed at the top and bottom of the arch,having little change with the development of creep;(3)with the increase of the burial depth,the change rate of the vertical deformation after reaching the stable deformation stage gradually increases,and the extreme value of the minimum principal stress of the lining also gradually increases,causing the increase of the compressive stress value on the lining structure.