Study on the Conventional Uniaxial Mechanical Properties and Micro-Mechanism of Sandstone under Dry-Wet Cycles

Dry-wet cycling has a significant impact on the mechanical properties of rocks, and a series of problems such as rock collapse can occur in rock masses under long-term dry-wet cycling. Based on this, some mechanical tests were carried out on sandstone under different dry-wet cycles to analyze the evolution law of its physical and mechanical parameters. The results show that the internal connection of the mineral becomes looser, the drying quality of the sample decreases, and the water absorption quality increases gradually under different dry-wet cycles. The peak strength of the sample decreases first and then increases with increasing dry-wet cycles. The change trend of the elastic modulus and deformation modulus with the increase in dry-wet cycles are similar to the peak strength, which is mainly related to the change in the connection between particles. Furthermore, the specimens showed axial tensile failure under uniaxial action. With the increase in dry-wet cycles, the tensile crack on the surface of the specimen increased, and the fracture of the specimen became looser. The specimen exhibited block spalling when the number of dry-wet cycles was eight times.