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黄土水平面内沉积结构及其发育的竖向裂隙构造使其具有明显的各向异性特征。通过黄土竖直裂隙向及其正交方向作用三维主应力状态几何空间八面体平面上3个空间域的真三轴试验,揭示了各空间域不同中主应力比值应力路径的剪切应力应变变化规律及抗剪强度变化规律。表明黄土竖向裂隙向作用大主应力的抗剪应力均大于水平面内正交两向作用大主应力的抗剪应力;中主应力增强作用能够诱导黄土的各向异性结构性;横观各向同性或者各向异性黄土八面体面上的强度破坏面随着平均球应力增大均呈椭圆、圆和曲边三角形变化,椭圆形破坏面可分别由轴对称压缩空间滑动面强度准则或轴对称挤伸空间滑动面强度准则近似地描述。
The sedimentary structure in the horizontal plane of the loess and its developed vertical fissure structure make it have obvious anisotropy characteristics. The true triaxial tests of three spatial domains on the octahedral plane in the three-dimensional principal stress state by the vertical fissure direction of loess and its orthogonal directions reveal the changes of shear stress-strain of stress paths with different medium-principal stress ratios in each spatial domain Law and shear strength changes. The results show that the shear stress of the large principal stress of the vertical cracks in the loess is larger than that of the large principal stress in the horizontal and vertical directions. The enhancement of the principal stress can induce the anisotropic structure of the loess. The same strength or anisotropy loess octahedron surface strength failure surface with the average ball stress are elliptic, circular and curved triangle changes, elliptical failure surface can be respectively by the axisymmetric sliding space sliding surface strength criteria or axisymmetric Extensional space sliding surface strength criteria are approximately described.