天坪隧道正洞巷道变形与耦合支护数值模拟研究与应用

Numerical Simulation Research of Deformation and Coupling Support of Tianping Main Tunnel and Its Application

针对天坪隧道正洞复杂地质条件下巷道围岩破坏失稳现状,利用FLAC3D有限差分程序建立数值模型,计算分析巷道围岩变形破坏特征,数值模拟显示了应力重新分布状态和围岩变形失稳状态。研究得出:距离巷帮7 m范围内垂直应力高度集中导致巷道出现"关键部位",成为巷道破坏失稳的关键因素。在此基础上,提出了相应的耦合支护对策,并模拟了支护对策的有效性。通过现场工程实践和效果监测,采用该支护对策后,巷道围岩变形量大幅度下降,最大位移量为222 mm,下降比例达85%,能够保证隧道的长期稳定。

To aim at the failure and instability of the roadway surrounding rock in Tianping main tunnel under the complicated geological conditions,a numerical model was established by FLAC3 D finite difference program software,the deformation failure features of the surrounding rock was analyzed by calculation,and the redistribution and instability state of the surrounding rock was showed by the numerical simulation. It was concluded by research that the highly concentrated stress in the range 7 m away from the roadway sides led to the appearance of the ＂key part＂in it,which become the key factor causing the failure and instability of the roadway. Based on this,the corresponding coupling support measure was proposed and its validity was simulated. The field engineering practice and effect monitoring indicated that the deformation amount of the roadway surrounding rock decreased significantly after taking this support measure,the maximum deformation amount was 222 mm,with a 85% drop,so it can ensure the long-term stability of the roadway.