1. MOE Key Laboratory of Deep Underground Science and Engineering,Sichuan University,Chengdu　 610065,China; 2. School of Architecture and Environ-ment,Sichuan University,Chengdu　 610065,China; 3. School of Economics and Management,Yibin University,Yibin　 644000,China

隧道常贯穿节理和断层,在隧道使用过程中,这两个方面对隧道的稳定性有很大影响。将节理及断层近似为穿越隧道的裂纹,通过模型试验和数值模拟相结合方法研究其在双轴压力作用下的损伤破坏规律。试验采用砂岩制作隧道模型,模拟采用Abaqus软件进行。使用Abaqus模拟计算出隧道围岩的应力分布以及裂纹尖端的应力强度因子,与实验结果比较吻合。结果表明:(1)穿越隧道不同倾角的裂纹对隧道的整体稳定性及强度的影响不同,在裂纹尖端产生的应力集中也不同,当贯穿裂纹倾角θ=40°时,裂纹对其整体稳定性及强度的影响最大,裂纹两端的应力集中现象最为明显,KⅡ值最大,隧道剪切破坏较为严重,破坏应力峰值仅为无裂纹模型的41.77%;(2)当贯穿裂纹位于θ=0°位置时,K_Ⅱ值很小且接近于0,在竖直压力下裂纹闭合,裂纹尖端的应力集中不明显,裂纹比较稳定,隧道的破坏应力最大,为无裂纹隧道模型的91.23%,即此位置是隧道稳定性最强位置;(3)隧道在竖直应力和侧向压力下,隧道的破坏主要表现为拱肩、边墙、裂纹尖端、拱脚的压剪破坏和拱底、拱顶的拉伸破坏。

The tunnels often cross joints and faults,which have great influence on tunnel stability during their use. In this paper,these joints and faults were approximated as the cracks through the tunnel. In order to study the influence of the cracks crossing the tunnel on tunnel stability under biaxial pressure,some model tests and numerical simulation were implemented. In the experiment study,Longchang sandstone was used to build tunnel models which were a square plate containing a small “ tunnel” and an inclined fault, and in the simulation, Abaqus software was used. Using Abaqus software,the stresses at the points around the tunnel and the stress intensity factor of crack tips were calculated which agreed well with the experimental results. The results show that:① Different angle cracks would have different influence on the stability and strength of tunnel,and produced different stress concentration at the crack tips. When θ is around 40 degrees,the influence of crack on the overall stability and strength of tunnel is maximum,the stress con- centration at crack tips is most obvious,KII value is maximum,its shear failure is more serious,and the peak of failure stress is only 41. 77% of that of tunnels without cracks. ② When θ is around 0 degrees,KII value is close to zero,un- der vertical pressure the cracks close,the stress concentration of crack tips are not obvious,the cracks are more stead- y,the failure stress of tunnel is maximum which is 91. 23% of that of tunnels without cracks,and this position is the strongest for the tunnel stability. ③ Under the influence of vertical stress and confining pressure,the tunnel failure is mainly the pressure-shear failure of the spandrels,side walls,crack tips,and skewbacks,and the tensile failure of arch bottom,vault.

LIU Bang,ZHU Zheming,ZHOU Lei,et al. Effect of the joints crossing the tunnel on tunnel stability[ J]. Journal of China Coal Society, 2018,43(5):1296-1304.