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为研究砂质泥岩各向异性特征,取长轴与层面不同夹角的圆柱试样,在岩石试验机上做了三轴剪切试验,得到应力-应变曲线,分析了围压和夹角对砂质泥岩强度及破坏模式的影响。结果表明,砂质泥岩在相同围压下,峰值强度及残余强度的关系随夹角呈U型曲线,且其各向异性程度随着围压的增加而降低。根据莫尔-库伦强度准则,砂质泥岩的内摩擦角与粘聚力随夹角呈凹型曲线。其破坏模式表现出明显的各向异性,可分为三类,即张拉剪切复合破坏、沿层面剪切破坏和贯穿层面剪切破坏。其中90°为张拉剪切复合破坏,60°和45°为沿层面剪切破坏,30°和0°为贯穿层面剪切破坏。试验结果可为砂质泥岩地区相关工程稳定性分析提供参考。
In order to study the anisotropy of sandy mudstone, a three-axis shear test was carried out on a rock testing machine by taking cylindrical specimens with different angles between the major axis and the plane. The stress-strain curve was obtained. The effects of confining pressure and angle on the sand Influence of strength and failure modes of mudstone. The results show that the relationship between peak intensity and residual strength of sandy mudstone under the same confining pressure is U-shaped with the included angle, and its anisotropy decreases with the increase of confining pressure. According to the Mohr-Coulomb strength criterion, the internal friction angle and cohesion of sandy mudstone are concave curve with the included angle. The failure modes show obvious anisotropy, which can be divided into three types: composite failure of tension and shear, shear failure along the plane and shear failure through the plane. Among them, 90 ° is tensile and shear composite failure, 60 ° and 45 ° are shear failure along the plane, and 30 ° and 0 ° are shear failure through the plane. The test results can provide references for the stability analysis of related projects in sandy mudstone area.