马鞍子梁软岩隧道围岩变形规律及支护技术模拟分析

Deformation Rule and Simulation Analysis of Supporting Technology on Soft Rock Tunnel in Maanziliang Tunnel

结合马鞍子梁隧道工程,采用FLAC数值模拟方法对该隧道上下台阶法施工全过程进行模拟分析,完成了现场监测研究,与数值模拟预测的结果进行了比较,得到了软岩隧道的围岩变形规律,提出合理的支护方案。结果表明,该开挖方法适用于此软岩隧道,竖向位移主要集中在拱顶和拱底处,拱顶位移比较大,水平位移主要集中在隧道两肩和两脚处。现场监测表明:隧道开挖初期拱顶下沉与水平收敛变形速率比较大,处于不稳定状态,随时间变形速率较小,曲线趋于稳定状态。FLAC数值模拟预测结果与实测结果基本一致,一次支护和二次衬砌的合理间隔时间为30d。

Combined with Maanziliang tunnel engineering,using FLAC numerical simulation method to analyze the whole process of benching tunneling method,the study on actual monitoring is completed.Compared with the numerical simulation results,authors get the soft rock tunnel surrounding rock deformation,and suggest the reasonable supporting scheme.The results show that the excavation method is applied for the soft rock tunnel.Vertical displacement is mainly concentrated on the top and bottom of the dome and the dome displacement is relatively large.Horizontal displacement is mainly concentrated on the shoulder and foot.The actual monitoring shows that the tunnel vault settlement and horizontal convergence deformation rate is relatively large during early stage and this period belongs to unstable state,over time the deformation rate is small and the curve tends to be stable.The FLAC numerical simulation results are basically the same as the measured results.The Reasonable interval between the first support and the second support is 30 days.