浅埋连拱隧道围岩参数反演及施工数值模拟

本文结合怀新高速公路的界牌坳隧道的实际情况,利用现场荷载试验的测点位移,通过有限元反演理论的模拟退火法反演计算隧道破碎带围岩基本参数.将反分析计算得到的隧道围岩参数输入界牌坳隧道二维弹塑有限元计算模型,对隧道的施工过程进行数值模拟,分析了采用三导洞法施工时围岩和中墙的受力变形规律,计算结果表明,两主洞拱部开挖是连拱隧道施工过程中两个比较关键的施工步;两主洞拱顶及右洞左拱肩位置的围岩出现了较大的位移或应变而有可能引起隧道塌方或破坏;浅埋偏压连拱隧道受山体偏压和不对称施工的影响,中隔墙在整个施工过程中基本处于偏心受压状态.

Displacement Back Analysis of Shallow Double -Arch Tunnel and Its Numerical Simulation of Construction Process

According to the real condition of Jie Pai Ao tunnel on the Huaihua-Xinhuang Highway,using test points' displacement of the field loading test,the tunnel crushed zone rock mass parameters were inversely computed out by the FEM inverse theory's simulated annealing approach in this paper.Jie Pai Ao tunnel construction steps' 2D elastic-plastic FEM computation model was set up by using these surrounding rock mass parameters.The stress and strain of surrounding rock and middle wall have been studied when the tunnel was constructed by the three-pilot drift construction method.The results indicate that the constructions of the two main tunnels' arch rock mass are the two key steps during the double-arch tunnel construction process.The displacement of two tunnels' vault rock mass and the plastic strain of the right tunnel's left spandrel rock mass are very big,which may cause the landslip or destruction of tunnel.For the bias of mountain body and the asymmetric construction of tunnel,the middle wall was at basically eccentric compressive state during the whole tunnel construction.