A novel damage model on the acoustic emission characteristics of weakly cemented soft rock under alkaline water-enriched environment

Abstract

Mechanical properties of weakly cemented soft rock (WCSR) under alkaline water-enriched environment are vital to the stability of surrounding rock. The specimens were soaked in various chemical solutions, and a series of experiments including X-ray diffraction (XRD), scanning electron microscopy (SEM) and uniaxial compression tests with acoustic emission (AE) were performed to study AE characteristics, damage evolution characteristics, and corrosion mechanisms of WCSR. The experimental results demonstrated that with the increase of pH values, the upward trend of the accumulative count curves became flatter, the crack propagation rate was more stable, and the energy release was more moderate. Cracks were classified based on AE characteristic parameters RA and AF. The difference between the tension cracks and shear cracks at deionized water and pH ​= ​7 solutions was smaller than 10%, while the difference between the pH ​= ​10 and pH ​= ​12 solutions was 19.6% and 26.54%, respectively. The increase in pH value significantly enhanced the propagation of tensile cracks and the complexity of failure model. Based on Mazars damage model, a novel damage model describing strain softening of WCSR was established by introducing accumulative count, which can better characterize the post-peak strain softening characteristics and damage evolution. In addition, the corrosion mechanism of soft rock under alkaline water-enriched is revealed from a microscopic perspective. The research results will provide significance guiding for deformation control of soft rock roadway and its disaster prevention under alkaline water-enriched environment.