Study on mechanical and energy characteristics of red shale under wetting-drying cycle

In order to reveal the mechanical properties and energy evolution law of red shale failure, triaxial compression tests were carried out on red shale by electro-hydraulic servo machine to study the peak strength characteristics, mechanical properties and energy evolution law of red shale samples under different wetting-drying cycles.The results show that the number of wetting-drying cycles has a significant influence on the compressive strength of red shale and is negatively correlated; the wetting-drying cycle will weaken the brittleness and increase the ductility of the rock sample in the failure stage, and reduce its physical and mechanical properties; compared with the deformation characteristic curves of the samples before and after wetting-drying cycle, the deformation of the original sample of red shale is about 1.7 times that of the sample after the wetting-drying cycle; after the destruction of the red shale, the growth rate of the dissipated energy of the original sample is 2.4 times that of the sample after the action of wetting-drying cycle, because the action of wetting-drying cycle will soften the internal structure of the red shale rock, making the volume strain change slowly during the destruction, resulting in the slower growth of the dissipated energy compared with the original sample.