小间距隧道围岩力学参数正交设计反演

根据西康高速公路18标长哨段的隧道围岩收敛位移现场监测结果,利用正交设计理论,对该区段小间距隧道围岩变形特性及塑性区大小影响较敏感的力学参数进行了反演分析,获得了比较接近工程实际的围岩综合力学特性参数,即千枚岩的弹性模量、泊松比、凝聚力和内摩擦角,有效地克服了千枚岩难于取样和难以进行力学参数试验的困难。利用反演分析所获得的力学参数对长哨小间距隧道的施工过程进行了数值仿真,分析了该隧道施工期间围岩的应力与变形规律,给出了围岩稳定性评价,为小间距隧道工程设计与施工提供了具有一定参考价值的重要资料和信息。

Back Analysis on Mechanical Parameters of Surrounding Rock of Tunnel with Small Spacing Using Orthogonal Design

According to the measured displacements of the surrounding rock of Changshao tunnel(18 sign) in Xi'an-Ankang expressway,the mechanical parameters which affecting the deformation characteristics and the size of plastic zone in surrounding rock of tunnel with small spacing were back analyzed based on orthogonal design theory,and the comprehensive characteristic parameters of surrounding rock of Changshao tunnel,that is elastic modulus,Poisson's ratio,cohesion and internal friction angle of phyllite,were obtained,which are close to factual engineering.The method has effectually overcome the difficulties of sampling in phyllite to make mechanical test of surrounding rock.The construction process of Changshao tunnel with small spacing was simulated by using numerical method and the mechanical parameters obtained by back analysis,and the laws of the stress and the deformation of the surrounding rock were analyzed for the tunnel during construction,and the evaluation of the surrounding rock stability was made.The study provided some important information for engineering design and construction of tunnel with small spacing.