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为研究十堰地区片岩的各向异性特性,开展了武当群绿泥石片岩长方体试样的单轴压缩和圆盘试样的间接拉伸试验,探讨了试样各向异性的力学特性和在不同受力状态下的变形破裂特性,揭示了不同变形破裂的力学机制。研究表明,武当群绿泥石片岩具有明显的各向异性性质,平行片理方向强度高,垂直片理方向强度低。该片岩特殊的定向排列片束状构造和片理间的弱胶结作用,致使不同方向上的破坏特征具有明显差异,其力学机制也不相同。在压应力作用下,泊松效应容易引起平行片理面的张拉劈裂和压杆失稳,垂直片理方向容易发生片理面间的剪切破坏。在同一方向上强度具有一致性,即平行片理面抗压和抗拉强度均较垂直片理面强度大。由于片理面间的抗拉承载力极低,在小角度劈裂荷载下,容易发生张拉劈裂和拉剪破坏,因此,实际工程中应尽可能避免片理面间的受拉破坏和沿片理的拉剪破坏。研究结果可以为隧道、边坡支护加固和防水处理提供参考。
In order to study the anisotropy of schist in Shiyan area, a uniaxial compression test and an indirect tensile test on disc specimens of chlorite schist cuboid samples were carried out. The mechanical properties of anisotropy of specimens were discussed. The deformation and rupture characteristics under stress state reveal the mechanical mechanism of different deformation and rupture. The study shows that the Wudantan chlorite schist has obvious anisotropy, high strength in parallel direction and low strength in vertical direction. The special orientation of the schist has a weak binding between the bundle-like structure and the interlaminar texture, resulting in significant differences in the damage characteristics in different directions. The mechanical mechanism is also different. Under the action of compressive stress, the Poisson effect can easily lead to the tension splitting and bar instability of the parallel facets, and the shear failure between the facets tends to occur in the direction of the normal sheeting. In the same direction, the strength is consistent, that is, the parallel facets have higher compressive strength and tensile strength than the vertical facets. Due to the extremely low tensile bearing capacity between the cleavage planes, the tension splitting and the tensile shear failure are easy to occur under the small angle splitting load. Therefore, the actual engineering should avoid the tensile failure between the splicing planes and Tensile damage along the filming. The results can provide reference for reinforcement of tunnels and slope support and waterproofing.