武当群片岩变形参数各向异性特征及机制研究

片岩因受片理面影响,其变形行为和破坏机制与一般岩体存在明显差异。为此,采用室内单轴压缩试验,研究了十堰-房县高速通省隧道武当群片岩在片理面倾角分别为0°、45°、90°时的变形参数各向异性特征及破坏机制。结果表明:片岩变形参数及破坏模式具有显著的各向异性特征。按照弹性模量E由大到小的顺序,试样的片理面倾角依次为:90°、0°、45°;按照泊松比v由大到小的顺序,试样的片理面倾角依次为:45°、0°、90°。片理面倾角为0°时试样以垂直片理面方向的压断破坏为主,45°时试样以沿片理面方向的纯剪切破坏为主,90°时以劈裂破坏为主。在此基础上,通过电镜扫描、FLAC3D数值试验结果等,分析了片岩变形破坏各向异性的机制,认为主要原因是片理面空间方位与轴向力方向不同的组合,导致软弱结构面——片理面对片岩变形的贡献差异明显。

Anisotropic properties of deformation parameters and its mechanism of Wudang group schist

The common character of schist is transversely isotropic due to the existence of regular bedding planes, which means that the failure mechanism and deformation characteristics of such rocks have the obvious difference with common rocks. In view of this point, 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: deformation parameters and failure mode of schist show obvious anisotropic characteristics. In the order of descending values of the modulus of elasticity, schistosity inclination of the samples are 90°, 0°, 45°respectively, in the order of descending values of the Poisson ratio, schistosity inclination of the samples are 45°, 0°, 90° respectively. The main failure mode is press off perpendicular to the spatial orientation of schistosity, shear and split off when schistosity inclination is 0°, 45°and 90° respectively according to schistosity inclination. Based on above, the mechanism of deformation and failure characteristics of schist is analyzed, via electron microscope scanning and FLAC3D numerical experiment, it is considered that, the main reason is the different relationships between spatial orientation of schistosity and axial force direction, which caused obvious differences of contribution that of schistosity surface to schist deformation.