P-wave velocity and density deterioration rules and parameters correlation of sandstone under water-rock interaction

Water is often involved in the damage of rock, further research should be conducted on damage and deterioration regulation of physical and mechanical properties of immersion-air dry rock. However, previous research involving immersion-air dry rock was mainly focused on statistical analysis of degradation and deterioration law of mechanical parameter, less attention has been paid to other physical parameters' variation, such as P-wave velocity, density and so on. Based on this, an experimental scheme considering immersion-air dry circulation under changing hydraulic pressure was designed, to analyse longitudinal wave velocity, density, fracture toughness and tensile strength of rock under different stages of immersion-air dry circulation. The results showed that in process of the circulation, longitudinal wave velocity and density have similar change rules, a significant descending trend grossly presenting as slow-steep-slow and that the P-wave velocity presented obvious correlation with fracture toughness, tensile strength and density, based on this, an equation been established to describe the relationship of P-wave velocity, density and fracture toughness. Validation results showed that the data predicted by empirical formula is credible. Therefore, changes in physical parameters, which are convenient and easy to measure, can be used to speculate changes in mechanical parameters and characteristics. © 2015 ejge.