隧道开挖穿越采空区变形破坏规律研究

Research on Deformation and Failure Laws of Tunnel Excavation Through Goaf

为了研究隧道开挖穿越采空区工况下的变形破坏规律,本文以宜毕高速公路张基屯隧道为工程背景,利用FLAC 3D数值计算软件建立隧道穿越采空区数值计算模型,对比分析隧道开挖过程中有无采空区条件下的竖向位移、水平位移和塑性区变化规律,及采空区的存在对隧道施工的影响。研究结果表明:由于采空区的卸载作用,隧道开挖过程中有采空区影响的水平位移和竖向位移均小于无采空区影响情况下的水平位移和竖直位移,隧道的水平位移、顶部沉降和底部隆起的最大值分别比无采空区时减小了55%、40%和85%,然而,隧道周边塑性区易与采空区发生连通,采空区顶部、底部、两帮的塑性区分别增大了220%、117%和117%。总体来说采空区的存在有利于隧道围岩的稳定控制。

In order to study the deformation and failure laws of tunnel excavation through the goaf, the Zhangjitun tunnel of Yibi expressway is taken as the engineering background in this paper, and FLAC 3 D numerical calculation software is used to establish the tunnel through the goaf.The numerical calculation model compares and analyzes the vertical displacement, horizontal displacement and plastic zone change law under the condition of whether there is a goaf during the tunnel excavation process, and the influence of the existence of the goaf on the tunnel construction.The research results show that due to the unloading effect of the mined-out area, the horizontal and vertical displacements affected by the mined-out area during tunnel excavation are smaller than the horizontal and vertical displacements and the horizontal displacement of the tunnel without the influence of the mined-out area.The maximum values of top subsidence and bottom uplift are reduced by 55%,40% and 85% respectively compared with those without mined-out areas.However, the plastic zone around the tunnel is easily connected to the goaf, and the plastic zones at the top, bottom and two sides of the goaf have increased by 220%,117% and 117%,respectively.Generally speaking, the existence of the goaf is beneficial to the stable control of the surrounding rock of the tunnel.