层理效应对黑色页岩抗拉强度影响及其能量分析

层理效应是影响页岩力学性能的主要因素之一,文章以龙马溪组黑色页岩为研究对象,进行了不同层理面角度页岩的巴西圆盘劈裂试验,研究了层理效应对黑色页岩抗拉强度和破坏模式的影响,并且分析了其破坏过程中能量的吸收规律,结果如下:(1)当加载方向与层理面平行时黑色页岩抗拉强度最小;(2)层理角度为0°时,黑色页岩的破坏模式为沿着层理面方向的开裂;当层理角度为22. 5°、45°、67. 5°时,页岩的破裂模为非中心破裂;当层理角度为90°时,页岩的破坏模式为中心开裂;(3)加载初期,能量吸收较慢,加载后期,能量吸收较快,能量吸收多少与层理面角度呈线性关系;(4)能量吸收和抗拉强度之间呈非线性关系,且与抗拉强度和层理面角度之间关系相似。

Influence of Bedding Effect on Tensile Strength of Black Shale and Its Energy Analysis

Bedding effect is one of the main factors influencing the mechanical properties of shale. Taking the Longmaxizu black shale as research object, Brazilian splitting test of shale is carried out from the different bedding plane angles, the influence of bedding effect on tensile strength and failure mode of the black shale is studied and the energy absorption law during the failure process is analyzed in the paper. The study results show that:(1) When loading direction is parallel to bedding plane, the black shale has the minimum tensile strength;(2) When the bedding angle is 0°, black shale cracks along the bedding plane direction, When the bedding angle is 22.5°, 45°, and 67.5°, non-central failure occurs in the shale, when the bedding angle is 90°, the central cracking occurs in the shale;(3) at the initial stage of loading, the energy absorption is slow, and at the late stage of loading, the energy absorption is fast, the energy absorption has a linear relation with the angle of bedding plane;(4) the relationship between energy absorption and tensile strength is non-linear, and similar that between tensile strength and angle of bedding plane.