分部开挖法施工隧道中隔壁优化研究

针对大跨度公路隧道施工采用分部开挖法时,其临时支撑施工速度慢、加工困难等问题,以G312线清水驿至傅家窑公路隧道为依托,将弧形中隔壁替换为竖直中隔壁,采用MIDAS GTS软件分别对两种中隔壁进行对比分析,并结合现场实测数据对数值模拟结果进行验证.研究相同结构不同材料强度中隔壁对大跨度隧道施工的变形及受力影响情况.结果表明:(1)两种中隔壁支护均能满足施工稳定性要求,竖直中隔壁的竖向应力相比弧形中隔壁增大了97.16%,采用竖直中隔壁时隧道围岩和中隔壁的位移变形相比弧形中隔壁更小;(2)对比大跨度隧道施工中分别采用I18和I22b两种不同型号的竖直中隔壁,得到采用I22b钢架的中隔壁产生的最大应力能降低23.09%.

Research on the optimization of the partition wall in the tunnel construction by the sub-excavation method

In view of the problems such as slow construction speed and difficult processing of temporary supports existing in the construction of long-span highway tunnels when the sub-excavation method is adopted, based on the tunnel of Qingshuiyi-Fujiayao Highway of G312 Line,the curved middle partition was replaced by the vertical middle partition,andthe numerical difference between these two partition walls was compared and analyzed using MIDAS GTS. Combining the on-site measured data, the numerical simulation results were verified, following the comparative of the deformation and stress effects of the partition walls of the same structure with different material strengths on the construction of large-span tunnels. The results show that: (1) Both kinds of middle partition support can meet the requirement of construction stability, in which the vertical stress of the vertical middle partition wall is increased by 97.16% compared with that of the curved middle partition wall, and the displacement and deformation of the tunnel surrounding rock and the middle partition wall adopting the vertical middle partition wall are smaller than that of the curved middle partition wall; (2) Comparing two different types of vertical middle partition walls, i.e. I18 and I22b, respectively, in the construction of long-span tunnels, it is found that the maximum stress energy generated by the middle partition wall using I22b steel frame can be reduced by 23.09%.