层状砂岩劈裂抗拉强度各向异性研究

为了分析层状岩体劈裂抗拉强度的各向异性,选取层理砂岩为研究对象,设计进行了加载线与层理走向垂直和平行的两组试验。结果表明:(1)加载线与层理走向垂直时,随着层理角度的增大,对应岩样的抗拉强度逐渐增大;加载方向与层理走向平行时,随着加载线与层理夹角的增大,对应岩样的抗拉强度也逐渐增大;(2)加载线与层理走向垂直时,层理效应系数在层理面法线方向与加载方向一致时最大,在层理面法线方向与加载方向垂直时最小;加载线与层理走向平行时,层理效应系数在层理面法线方向与加载方向垂直时最大,在层理面法线方向与加载方向一致时最小;(3)加载线两侧层理结构称对称分布时,试样的破裂面是一条通过圆心的直线,破坏模式为直线型;层理结构关于加载线不对称时,试样的破裂面往往由多段折线或者弧线构成,破坏模式为折线型或弧线型。研究结果为比较全面地把握层状岩体抗拉强度各向异性提供了较好的参考。

Experimental Study on Anisotropic Properties of Splitting Tensile Strength of Bedding Sandstone

In order to analyze the anisotropic properties of splitting tensile strength of bedding rock, the bedding sandstone was chosen as a research object. Two groups of tests, in which the loading line is perpendicular or parallel to stratification, are designed. The results show that: (1)When loading line and stratification are perpendicular, the tensile strength increases with the increasing of bedding angle. When loading line and stratification are parallel, the tensile strength also increases with the increasing of the bedding angle. (2)In the condition of loading line and stratification are perpendicular, bedding effect coefficient maximizes when the loading line is parallel to the normal direction of the bedding plane, and minimizes when the loading line is parallel to normal direction of the bedding plane. In the condition of loading line and stratification are parallel, bedding effect coefficient maximizes when the loading line is perpendicular to the normal direction of the bedding plane, and minimizes when the loading line is parallel to the normal direction of the bedding plane. (3)When bedding structure is symmetrical distributing around the loading line, fracture surface shape of the sample is a straight line through the center, and the failure mode can be summarized as linear. When bedding structure is not symmetrical distributing around loading line, fracture surface shape of the sample consists of multistage lines of curve, and the failure mode can be summarized as bent and arc. The research results provide a good reference for making a comprehensive understanding of anisotropic properties of tensile strength of bedding rock.