偏压连拱隧道中隔墙力学特征数值分析

中隔墙作为连拱隧道的中枢结构和重要承载构件，其受力及位移情况往往对工程成败和安全起着决定性作用。本文采用有限元方法对某浅埋偏压连拱隧道的开挖过程进行模拟，对连拱隧道中隔墙受力特征作了计算分析。结果表明，中隔墙是连拱隧道最主要的受力构件，偏压开挖容易在中隔墙引起较大偏心荷载，偏压连拱隧道采用复合曲中墙结构将有助于改善中隔墙受力状况，减小应力集中及上部位移；并结合中隔墙主筋轴力量测，对连拱隧道中隔墙施工进行了监控分析，监测结果表明，隧道由于偏压荷载的存在，应先开挖深埋侧隧道，此时中隔墙结构的扭转和偏心都较小。

Numerical analysis on mechanical behaviors of the mid-partition wall in double-arched unsymmetrical pressure tunnel

The mid-partition wall is the important bearing structure of the double-arched tunnel.The bearing pressure and the deformation of the wall usually dominate the success and safety of the tunnel project.The FEM is used to simulate the excavating process for a double-arched tunnel with the shallow burying and unsymmetrical pressure.The results show that the mid-partition wall is the key load-carrying member, and the nonsymmetrical excavating would easily bring the eccentrical loads on the wall.The double-arched tunnel which adopted the multiple bent mid-board structures would be helpful to improve the bearing behaviors of the mid-partition wall and to decrease the concentration of stress and the top displacement.Based on the measuring of the force of reinforcing steel bars in the wall,the monitoring and analysis on the construction of the mid-partition wall are carried out.The monitoring results show that owing to the existence of the eccentric loads the tunnel at the deep-buried side should firstly be constructed,which makes the twisting force and the eccentricity in the wall structure are low.