高宽比对隧道围岩稳定性的影响

Effect of the Ratio of Depth to Width on Tunnel Stability

为研究隧道截面形式对隧道围岩的影响,结合模型试验和数值模拟研究高宽比K变化时,马蹄形隧道围岩稳定性及损伤破坏规律。考虑隧道周边无宏观裂纹和含有单一裂纹2种情况,数值模拟采用ABAQUS混凝土塑性损伤模型,计算隧道周边应力;对含有裂纹的情况利用J积分计算出裂纹尖端应力强度因子,利用ABAQUS中XFEM(extended finite element method)扩展有限元技术模拟高宽比为1.5时裂纹的发展路径和应力分布,与模型试验吻合较好。结果表明:隧道围岩的稳定性和损伤破坏情况随隧道高宽比K的变化而变化,对无裂纹模型,试件抗压强度在K=1.5时最大,K=1.0时最小;对有裂纹隧道模型,试件抗压强度在K=1.7时最大,K=0.7时最小。

In order to investigate the effect of depth-width ratio of tunnel on the tunnel stability,experiment in combination with numerical studies were adopted.The case of a tunnel containing a crack was also considered.Stresses around the tunnel were calculated by using concrete damaged plasticity model in ABAQUS code,and for the tunnel with crack the stress intensity factors were calculated with J integral method,and for depth-width ratio 1.5 case,XFEM(extended finite element method) in ABAQUS code was adopted to simulate the crack development path,and the results were in good agreement with the experimental results.The results showed that tunnel stability varies with the variation of depth-width ratio K.For non-crack tunnel model,the compressive strength comes to the largest with K = 1.5 and comes to the lowest with K = 1.0,and for tunnel model with one crack,the compressive strength comes to the largest with K = 1.7 and comes to the lowest with K = 0.7.