Study on Failure Mechanism and Numerical Simulation of Argillaceous Slate in Southeastern Guizhou

[Image: see text] The content of quartz and clay minerals has a crucial influence on the mechanical properties of slate, which is manifested by the differences in microscopic displacement and energy conversion during uniaxial compression. With Qiandongnan argillaceous slate in Guizhou Province as the research object, the parameters for numerical simulation were determined through indoor uniaxial tests, and argillaceous slate models with different mineral contents were established to analyze crack formation and energy conversion during uniaxial compression. The damage rate of the specimen was qualitatively analyzed by the fractal dimension of the crack. The results show that ① the number of fractures increases with the increase of quartz content, and the number of cracks in Group 4 is 33.4% higher than that in Group 1, and macroscopic fractures are dominated by cracks while microscopic fractures by tension fractures, accompanied by a small amount of shear; ② the energy change curves of the four groups of specimens are consistent with the stress–strain curves, which are divided into three stages, namely elastic deformation, yield, and strength loss. The strain energy in the strength loss stage is negatively correlated with the dissipated energy, and the dissipated energy of the four groups of specimens is positively correlated with the content of quartz; ③ the damage rates for the specimens in Groups 1 to 4 quantitatively analyzed using fracture fractal dimension are 56.8, 59.1, 65.8, and 70.7%, respectively. The research results obtained in this article have further improved the failure mechanism of argillaceous slate under uniaxial compression.