阳坡里隧道纵穿滑坡体段变形破坏机制与加固效应研究

Study of deformation and failure mechanism and reinforcement effect of Yangpoli tunnel longitudinally traversing landslide

以武罐高速公路阳坡里隧道为依托,深入探讨了隧道纵向穿越滑坡体情况下隧道与滑坡的相互作用机制及变形破坏模式。在理论分析的基础上提出了针对性的综合工程防治设计方案,并采用强度折减有限元法与极限平衡法对隧道穿越滑坡段的开挖加固效应进行了分析研究,对开挖加固前、后滑坡的稳定性进行了对比分析。结果表明:在隧道开挖条件下,滑坡的稳定性满足规范要求,目前该工程正在施工中,安全稳定性良好。另外,研究表明:纵穿滑坡体段的隧道结构对滑坡体来讲是一个重要的"抗滑结构体",由于受滑坡推力作用隧道衬砌结构所受主应力发生明显偏转,当进入基岩后,随着隧道拱顶距基岩与覆盖层接触面距离的增加,衬砌所受各主应力逐渐转变为正常状态。提出的隧道纵穿滑坡段的分析思路和综合防治方案对类似工程有一定的借鉴和指导意义。

Based on Yangpoli tunnel in Wudu-Guanzigou expressway,both the interaction mechanism and the deformation and failure mode between tunnel and landslide in the condition of tunnel traversing landslide longitudinally are deeply discussed.On the basis of theoretical analysis,a relevant comprehensive controlling design is put forward.Furthermore,the strength reduction finite element method and limit equilibrium method are carried out to analyze the excavation reinforcement effect for the tunnel crossing landslide.The comparison analysis of stabilities before and after excavation illustrates that under the excavation,the landslide stability meets the design specifications of the code.So far,the engineering is under construction and the safety stability is in good condition.In addition,studies show that： the tunnel structure crossing landslide longitudinally works as a major ＂anti-sliding structure＂ in terms of landslide;due to the effect of landslide thrust,the principal stresses of tunnel lining suffer apparent deflection.When entering the stable bedrock,with the increasing of distance between tunnel vault crown and the interface of bedrock and alluvion covering,the principal stresses of tunnel lining gradually transform into normal state.The analysis of tunnel crossing landslide longitudinally and comprehensive controlling scheme will provide a guidance for similar engineering.