Experimental investigation of cyclic wetting-drying effect on mechanical behavior of a medium-grained sandstone

As a typical form of weathering, cyclic wetting-drying treatment on host rock is commonly encountered in many applications of geotechnical engineering. How cyclic wetting-drying weathering affects the strength and deformation behavior of host rock is a topic worthy of comprehensively investigating. In this study, the influence of cyclic wetting-drying weathering on mechanical behavior of a medium-grained sandstone is experimentally investigated. The sandstone specimens are first subjected to different wetting-drying weathering cycles, and uniaxial compression tests and direct shear tests are then conducted on these prepared specimens. The results show that the water absorption of the rock monotonically increases with the increase of the number of wetting-drying cycle in the treatment. The strength and deformation properties (i.e., uniaxial compressive strength, Young's modulus, cohesion, and friction angle) are found to decrease with the increase of wetting-drying cycle in the treatment and the decrease gradually diminishes as the number of wetting-drying cycle becomes large. Upon failure of the rock specimen under both uniaxial compression and direct shear, the integrity is progressively weakened and more fragments can be observed as the number of wetting-drying cycle in the treatment gradually increases. The deterioration of rock strength and deformation properties is found to be mainly associated with the micro-cracks generated inside the rock in response to cyclic wetting-drying weathering. The data in this study provide useful guidance for long-term stability evaluation of engineering structures constructed under cyclic wetting-drying weathering condition.

Automated summary

The cyclic wetting-drying weathering has a significant impact on the mechanical properties of medium-grained sandstone, leading to an increase in water absorption and a decrease in strength and deformation properties as the number of cycles increases. The integrity of the rock specimens weakens progressively with more wetting-drying cycles, resulting in more fragments upon failure. The deterioration in rock strength and deformation properties is primarily attributed to the micro-cracks generated in response to cyclic wetting-drying weathering, which provide valuable insights for the long-term stability evaluation of engineering structures.