Effect of Water-Rock Interaction on the Compressive Mechanical Properties and Mesoscopic Structure of Granite

Abstract

Abstract Understanding the impact of water-rock interaction on the mechanical characteristics of rock is of great practical significance in rock engineering. To investigate water-rock interaction on the compressive mechanical properties and mesostructure of granite, specimens were immersed in pure water at 25℃ for 0, 2, 4, and 6 months, then subjected to impact compression tests at different strain rates to analyze the effect of water-rock interaction on mechanical characteristics. Furthermore, mesoscopic experiments such as optical microscope, atomic force microscope, nuclear magnetic resonance and water quality detection were used to explore the meso-structural changes caused by water-rock interaction and reveal the mechanism of water-rock interaction. Finally, a pore size-based and weighted damage evolution model and a water-induced strength softening factor were introduced to describe the damage evolution characteristics and mechanical property degradation mechanism of granite under water-rock interaction. The results show that the uniaxial compressive strength of granite is linearly negatively correlated with the duration of water immersion, and logarithmically positively correlated with the strain rate; the longer the immersion duration, the more sensitive the granite is to the strain rate. During the water-rock interaction, chemical and physical reactions occur between water and granite, which jointly promote pore development. However, the time scale of the two is not consistent. The chemical effect slows down with time, and the physical effect is the opposite.