基于强度折减法小净距隧道合理净距的研究

On rational clear spacing of tunnel with small clear spacing based on strength reduction technique

小净距隧道合理净距的确定是目前研究的热点和难点。影响小净距隧道合理净距的因素很多,解析法虽然可以得到精确解,但是公式烦琐,而数值计算方法可以计算各种情况下围岩的应力、变形、塑性区分布等情况。小净距隧道合理净距的确定也即是隧道稳定性发生突变时两独立隧道最小距离的确定。提出了合理净距确定的原则,并采用强度折减弹塑性有限元方法,针对某工程实例,计算了在不同净距情况下隧道的安全系数,并把安全系数发生突变时的净距作为合理净距,和传统有限元分析的结果相吻合。

Tunnel with small clear spacing is a hotspot and difficult problem. Many factors affect the optimized spacing of tunnel with small clear. Numerical method can consider all kinds of factors. The rational spacing is the nearest distance between two tunnels when catastrophe. The principles of determining the optimized spacing are proposed. Using strength reduction elastoplastic FEM and taking some project as example, the paper calculates the safety factors at different spacing and takes the distance as the optimized spacing when catastrophe, which is consistent with the traditional FEM result.