受偏压隧道影响边坡加固的数值分析

Numerical Analysis of Slope Reinforcement with Effect of Bias Tunnel

针对隧道工程建设中切坡引起边坡及隧道的变形,其稳定性受到不同程度的影响,采用三维有限差分计算程序FLAC3D分析挖方边坡和坡顶隧道联合稳定性。通过对未开挖、未加固边坡进行数值模拟计算,得到水平位移和最大、最小主应力分布特征,分析其潜在滑动面和隧道围岩受拉影响区,确定其加固范围。根据抗滑桩受力特点,经比选,采用单排抗滑桩加固隧道边坡。数值计算结果表明:有限差分法能获得单排抗滑桩的合理设计和边坡坡脚及坡面受力情况,同时还能得到隧道围岩拉压应力的分布及优化覆盖层厚度,数值计算与工程监测数据吻合。

Aimed at the different influence of slope and tunnel deformation caused by slope cutting on stability of tunnel adjacent slope, the combined stability was analyzed by using 3D finite difference program FLAC3D. The distribution characters of horizontal displacement, maximum and minimum principal stresses were calculated by numerical simulation of the slopes without cutting and reinforcement. The potential sliding surface and tensile stress region for tunnel slope without cutting and reinforcement were analysed to determine its reinforcement scope. Based on the mechanical characters of anti-sliding piles, the single-row anti-slide piles were adopted for tunnel adjacent slope reinforcement after comparison. The numerical calculation result shows that （1） reasonable designed parameters can be obtained for single-row anti-sliding piles and mechanical characters can also be markedly improved between toe and surface of slope by finite difference program; （2） distribution of tensile-compressive stress region in wall rock region and optimized roof thickness were obtained in favor of enhanced stability. The numerical calculation is coincident with the monitoring data.