鄂西北片岩变形参数各向异性及水敏性研究

ANISOTROPIC AND WATER SENSITIVITY PROPERTIES STUDY OF SCHIST DEFORMATION PARAMETERS IN NORTHWEST OF HUBEI PROVINCE

为研究鄂西北地区片岩变形参数的各向异性及水敏性,对十堰—房县高速通省隧道片岩开展片理面倾角为0°,45°,90°的天然及饱和状态下单轴压缩试验。结果表明:片岩变形参数的各向异性及水敏性特征十分明显,相同含水状态时片岩弹性模量由大到小分别为:90°>0°>45°,天然试样泊松比由大到小分别为:45°>0°>90°,饱和试样泊松比v由大到小分别为:90°>0°>45°;片理面倾角相同时,天然试样弹性模量均大于饱和试样,泊松比随试样含水状态的变化与片理面倾角有关,片理面倾角为0°时,天然状态泊松比等于饱和状态,片理面倾角为45°时,天然状态泊松比大于饱和状态,片理面倾角为90°时,天然状态泊松比小于饱和状态;片理面倾角为0°时主要发生垂直片理面方向的剪断破坏,45°时多沿片理面发生纯剪切破坏,90°时主要发生沿轴向的劈裂破坏。片理面倾角与含水状态对片岩变形参数及破坏形式影响显著的主要原因是:片理面法线方向与轴向力方向的不同组合情况,导致软弱结构面–片理面对片岩变形的贡献程度不同。研究结果可为类似片岩地区隧道设计、开挖、支护及防水处理等提供参考。

In order to study anisotropic and water sensitivity properties of schist in northwest of Hubei province,Uniaxial compressive test on samples of Wudang Group schist,Tongsheng tunnel,Shiyan—Fangxian expressway,that with schistosity inclination of 0°,45° and 90° respectively is carried out. The results show that：Schist shows obvious anisotropic and water sensitivity properties,in the same state of water content,modulus of elasticity is 90°〉0°〉45°,Poisson ratio of natural state is 45°〉0°〉90°,and saturated state is 90°〉0°〉45°. In the same state of schistosity inclination,the modulus of elasticity of natural samples is larger than saturated samples,and Poisson ratio is related to schistosity inclination. Poisson ratio of saturated sample is equal to native state,when schistosity inclination is 0°,saturated sample is larger than to native state when schistosity inclination is 45°,and saturated sample is less than to native state when schistosity inclination is 90°. The main failure mode is press off,shear and split off when schistosity inclination is 0°,45°and 90° respectively. The main reason that schistosity inclination and water content has significant effect on deformation parameters and deformation and failure mode of schist is that,the different relationship between spatial orientation of schistosity and axial force direction,which caused obvious differences of contribution that of schistosity surface to schist deformation. The results can be reference for design,excavation,reinforcement and water-proof treatment of tunnel.