Evolution Mechanism of Mesocrack and Macrocrack Propagation in Carbonaceous Mudstone under the Action of Dry-Wet Cycles

The crack propagation evolution of carbonaceous mudstone under the action dry-wet cycles is an important cause unstable failure this type slope. This paper attempts to reveal mechanism mesocrack and macrocrack in from chemical, physical, mechanical perspectives. Firstly, soaking solution during was extracted for ion concentration test analyze chemical reactions mudstone. Then, CT scans were performed on samples study changing pattern mesostructure cycles. In end, properties characteristics after studied by triaxial compression tests. results showed that such as calcite dissolution, potassium feldspar hydrolysis, sodium hydrolysis occurred cycle Affected cycles, gradually changed face-face contact edge-face edge-corner corner-corner contact, interlayer flake structure opened locally curled fractured. With increase number characteristic transformed tensile shear failure, surface deflected 90° 60°, path became more complicated. reaction minerals reason initiation development pores. aggregates mesocracks structural disorder, transforming uniform stress state rock concentrated state, which