大断面隧道穿越层状围岩段初期支护优化研究

Stability Analysis and Optimization of Primary Support on Tunnel Excavation with Soft-hard Interbed Rock

在层状类围岩中进行开挖施工易造成边墙弯曲-溃曲、底鼓以及顶板弯曲等现象的产生。为此,依托重庆市某层状围岩隧道工程,基于该隧道的工程地质特征及地层岩性分布,着重考虑岩层与锚杆夹角之间的关系,采用ANSYS静力有限元数值分析程序,对该隧道层状Ⅴ级泥岩段的受力变形特征进行模拟分析,并优化了初期支护参数。数值模拟结果显示当取消与岩层夹角为30°以下的锚杆,衬砌及锚杆的受力变化幅度较小。该研究方法及成果建立于实际工况的基础上,运用数值的方法还原现场支护受力状态,相应的分析方法及研究结果可为类似隧道、矿山巷道工程的设计、施工提供一定的借鉴和参考。

Excavation in layered surrounding rocks is liable to cause side wall bending-buckling, bottom drum and roof bending. Therefore, based on a layered surrounding rock tunnel project in Chongqing, the stress and deformation characteristics of the layered mudstone section of the tunnel were simulated and analyzed, and the initial support parameters were optimized. By ANSYS static finite element numerical analysis program, combined with the engineering geological characteristics of the tunnel and the lithological distribution of the stratum, the research focused on the relationship between the angle between the rock layer and the anchor. Based on comprehensive research results, an optimal plan for the initial support of the layered mudstone section of the tunnel is obtained, that is, the upper step anchor rod with an angle of 30 ° between the anchor rod and the rock layer is eliminated. The research method and results are based on the actual working conditions, and the numerical method is used to restore the on-site support force state. The corresponding analysis methods and research results can provide some reference for the design and construction of similar tunnels and mine roadways.