近水平软弱岩层高速公路隧道施工方案比较

The Comparative Study on Construction Schemes of the Approximate Horizontal Weak Rock Expressway Tunnel

近水平软弱岩层具有抗压强度低、节理裂隙发育、物理各向异性明显等特点,一直是隧道工程研究领域的一个热点问题,本文以广南高速公路栾家岩隧道为例,采用正交各向异性有限元模型对隧道Ⅴ级围岩条件下台阶法和CD法两种开挖方法的变形及受力特性做了详细的比较分析,最终得出结论,建议广南高速公路栾家岩隧道Ⅴ级围岩条件下,施工时采用CD法开挖对于施工过程中围岩及衬砌结构受力较台阶法更为有利。研究也可为近水平软弱岩层条件下的其它类似隧道工程提供参考。

The approximate horizontal weak rock has low compressive strength,developed joint and fracture,obvious physical anisotropy etc and is always a hot issue in tunnel engineering.In this paper,the Luanjiayan expressway tunnel is taken as the example.The deformation and stress characteristics of Ⅴ grade rock under different construction schemes,namely the step-method and the CD-method,are analyzed in detail using the orthotropic FEM model.Through the comparison of the deformation and stress under two construction schemes,the CD-method is more favorable to the surrounding rock and tunnel lining structure of Luanjiayan expressway tunnel.This work can offer reference for other tunnel engineering in approximate horizontal weak rock.