Effect of heterogeneity on mechanical and acoustic emission characteristics of rock specimen

Abstract

The influence of heterogeneity on mechanical and acoustic emission characteristics of rock specimen under uniaxial compress was studied with numerical simulation methods. Weibull distribution function was adopted to describe the mesoscopic heterogeneity of rocks. The failure process of heterogeneous rock specimen under uniaxial loading was simulated using FLAC^3D software. Five schemes were adopted to investigate the influence of heterogeneity. The results demonstrate that as the homogeneity increases, the peak strength and brittleness of rocks increase, and the macro elastic modulus improves as well. Heterogeneity has great influence on macro elastic modulus and strength when the homogeneity coefficient is less than 20.0. The volume expansion is not so obvious when the homogeneity increases. As the homogeneity coefficient increases the acoustic emissions modes change from swarm shock to main shock. When the homogeneity coefficient is high, the cumulative acoustic emission events-axial strain curve is gentle before the rock failure. The numerical results agree with the previously numerical results and earlier experimental measurements.

Keywords

heterogeneity / acoustic emission / strain softening / numerical simulation / uniaxial compression / elastic modulus