基于不同地表倾角的连拱隧道施工优化分析

基于平面应变问题,采用Druck-Prager屈服准则,研究不同地表倾角对偏压连拱隧道不同施工方法的施工力学性能的影响.通过对隧道二次衬砌力学特性及中隔墙受力分析,确定其较优的施工方法.模拟结果表明:地面倾角为5°~15°时,宜先开挖埋深较小一侧;地面倾角为15°~30°时,若能确保中隔墙稳定,则宜先开挖埋深较小一侧;反之,宜先开挖埋深较大一侧;先开挖洞室的墙脚安全系数较小,在施工中应注意加强.

Optimization of Construction Procedures in a Double-arch Tunnel Based on Different Slope Angles of Surface Ground

Construction mechanics caused by different construction procedures under different slope angle of surface ground are analyzed based on a plain strain problem using Druck-Prager yield law in a partial pressure double-arch tunnel.Optimization of construction procedures is got by comparing mechanics of secondary lining and middle wall.Results show that it is reasonable to firstly excavate the shallower tunnel when the slope angle is between 5 degree and 15 degree.When it is between 15 degree and 30 degree,it is also reasonable to first excavate the shallower if the middle wall is steady.However,if the middle wall is unsteady due to seriously partial pressure,it is better to excavate the deeper tunnel.Finally,safety coefficient is very small in the feet of the wall,so we'd better reinforce it and pay much attention to it during construction.