张集铁路旧堡隧道围岩初始应力反演分析及分级评价

Back Analysis and Grading Evaluation of Surrounding Rock Primary Stress in a Railway Tunnel

隧道围岩初始应力分析评价是进行围岩稳定性分析、实现隧道安全快速掘进的前提.采用位移反演分析和场区构造地应力分析2种方法,对旧堡隧道围岩初始应力状态进行分级评价.研究表明,开挖区段隧道横截面上平行洞轴方向为最大主应力方向,围岩的最大、最小主应力均大于自重应力,岩石强度应力比低,该隧道围岩的初始应力属于高地应力.

The study and evaluation of primary stress of tunnel surrrounding rocks is a necessary premise of conducting stability analysis of surrounding rocks and achieving and quick safe tunnel excavation. Two methods, including displacement back analysis and in-situ geological structure stress analysis, are taken to conduct grading cvaluation on primary stress condition in a railway tunnel. The study results show that the direction of paralleling axis of the tunnel on cross section is the direction of maximum main stress, and both the maximum main stress and the minimum main stress in surrounding rocks are larger than self-weight stress, and the ratio of stress to strength in surrounding rocks will be large. Therefore, the surrounding primary stress state in the tunnel is in high level earth stress.