关键词: 千枚岩, 层理, 含水率, 孔洞, 巴西劈裂

Abstract: Phylite is widely distributed in southwest of China. Factors such as groundwater, bedding, micro-pores and micro-cracks will weaken its mechanical properties to some extent, thus posing severe challenges to the stability of the related projects. Therefore, in this paper, based on Brazilian splitting test, the evolutions of the tensile strength, energy and failure forms of phyllite under the coupling effects of water, bedding and pore are studied. The results show that the tensile strength decreases gradually with the increase of moisture content, pore diameter and bedding angle. However, the tensile strength has different sensitivities to the changes of them, which is mainly reflected in that bedding angle is the most significant, pore diameter is the second, and moisture content is the least. The tensile strength shows obvious anisotropy under different beddings. The anisotropy of tensile strength increases with the increase of water content and pore diameter, and the rate of increase with water content is more significant. Moreover, the energy increases gradually with the increase of moisture content, pore diameter and bedding angle, which is consistent with the changes of tensile strength. Although the energy under different beddings also presents obvious anisotropy, its anisotropy degree is generally higher than that of the tensile strength under the same condition. The failure form of specimens is affected by pore size, bedding angle and moisture content, among which, the existence of hole mainly affects the crack initiation position, the size of pore mainly affects the crack initiation strength, the bedding angle mainly affects the crack propagation path, and the moisture content mainly affects the number of cracks. This research results are valuable for further understanding the tensile properties of rocks and improving the stability of geotechnical engineering.

Key words: phyllite, bedding, moisture content, hole, Brazilian splitting