隧道软弱围岩进洞稳定性分析

隧道进出洞口处是地质灾害多发的地段.以某工程为背景,采用有限元强度折减法,研究隧道开挖过程中安全系数的变化情况,对隧道进洞口浅埋段发生坍塌破坏的规律及机理作深入解释.计算分析表明,因为算例隧道处于坡脚位置,开挖引起边坡失稳是导致软弱围岩隧道进洞灾害多发的根本原因,针对这种地质条件下隧道进洞的安全隐患,对其设计和施工提出一些合理化建议.

Analysis for Stability of Weak Wall Rock at Entrances of Tunnels

Entrances of tunnels are geological disasters-prone sections.With some project as background,this paper investigates changes of safety factors during excavation of tunnels by means of finite element strength reduction method and deeply explains laws and mechanisms of damage of collapse in shallow buried sections at the entrance of tunnels.Computation and analysis show that loss of slope stability due to excavation is a fundamental reason for many disasters at the entrances of tunnels with weak wall rock because the exampled tunnel is located at the position of slope toe.Aiming at potential safety hazard at the entrance of tunnels under such geological condition,the paper puts forward some reasonable proposals for design and construction.