基于有限差分法的公路隧道衬砌结构数值计算

摘要

Dependent on the Chonganjiang Tunnel Project, this paper selects lining structure forms at 3 different grades of wall rocks for numerical calculation, analyzes internal force, safety factor, peripheral convergence, crown settlement of lining structure and plastic zone of wall rocks and evaluates safety of lining structure. The results show that for wall rocks at grades V andⅣ, crown settlement is mainly caused by excavation of central area of upper and lower steps, the plastic zone of wall rocks develops greatly and even to earth surface, and the plastic zone at the foot of gradeⅣwall rock is large;for gradeⅢwall rock, crown settlement mainly attributes to excavation of upper step and the plastic zone of wall rock is small.%以重安江隧道工程为依托,选取3种不同围岩级别的衬砌结构形式进行数值计算,分析衬砌结构内力、安全系数、周边收敛、拱顶下沉、围岩塑性区,并评价衬砌结构的安全性。结果表明：对于V、Ⅳ级围岩,拱顶下沉主要是由上台阶及下台阶中央区开挖所致,V级围岩地段,围岩塑性区发展很大,甚至发展到地表,Ⅳ级围岩墙脚处塑性区较大；对于Ⅲ级围岩,拱顶下沉则主要是由上台阶开挖所致,围岩塑性区较小。