构造应力场对隧洞围岩应力和变形破坏特征影响的研究

Influence of the Tectonic Stress Field on Stress and Deformation Failure Characteristics of a Tunnel's Surrounding Rock

依据某隧洞和实测地应力资料,利用有限差分软件FLAC3D模拟了不考虑构造应力作用和考虑构造应力作用条件下隧洞开挖后围岩的应力和变形破坏特征。结果表明:隧洞开挖后围岩应力出现明显的变化,无构造应力作用时,在隧洞侧壁围岩中出现应力集中;有构造应力作用时在隧洞的顶部和底部的围岩中出现应力集中,且应力集中的区域和量值明显增大。无构造应力作用时,隧洞顶拱和底部处位移和影响深度最大,隧洞围岩变形区域的外边界为竖向"蝴蝶型";有构造应力作用时,侧壁处位移和影响深度最大,隧洞围岩变形区域的外边界为横向"蝴蝶型"。洞室围岩剪应变增量区域的外边界无构造应力作用时近似为竖向椭圆形,有构造应力作用时则为横向椭圆形。研究成果对构造应力区深埋隧洞的稳定性分析以及支护设计具有一定的借鉴意义。

Based on the measured geostress of a tunnel and FLAC3 Dsoftware, stress and deformation failure char-acteristics of surrounding rock after tunnel excavation were simulated with or without consideration of tectonicstress. The results show that： 1） obvious changes to rock stress occur after tunnel excavation, with stress concentra-tion occurring on the sidewall under no tectonic stress and on the top or bottom of the tunnel under tectonic stress,and the area and degree of the stress concentration under a tectonic stress are significantly greater than that underno tectonic stress; 2） the maximum displacement and influence depth occur on the top and bottom of the tunnel un-der no tectonic stress while they occur on the sidewall under tectonic stress; 3） the outer boundary of the deforma-tion area is shaped like a vertical butterfly under no tectonic stress while it is shaped like a horizontal butterfly un-der tectonic stress; 4） the outer boundary of the shear strain increment area is approximately shaped like a verticalellipse under no tectonic stress while it is shaped like a horizontal ellipse under tectonic stress. The research re-sults have particular significance for the stability analysis and support design of deep buried tunnels in zones withtectonic stress.