Damping and Stiffness Responses of Silica Rock under Constant Amplitude and Variable Rate Cyclic Loading

Abstract

In this paper, the shear modulus and damping ratio of silica rock under cyclic loading were experimentally analyzed using two loading modes, constant amplitude and increasing amplitude, combined with three increasing loading rates. Observations have indicated a decrease in the shear modulus of specimens as the number of cycles increased during the loading and unloading phases and an overall increase with larger amplitude intervals. The change in loading rate significantly affects the damping ratio of the specimens, leading to a stepwise decrease within the same cyclic group, while the damping ratio of a single specimen exhibits a ‘concave’ distribution throughout the cyclic interval. Based on the axial strain and dissipation energy, this paper develops two damage models that can effectively predict the damage accumulation process in rocks under cyclic loading. These findings have significant implications for a deeper understanding of the mechanical behavior of rocks under dynamic loading and offer theoretical guidance and technical support for rock engineering.