Numerical study on the attenuation of high-amplitude stress wave in rock bar along with rock damage evolution

Abstract

The attenuation of high-amplitude stress waves in the rock and the rock failure caused by the stress waves have significance for vibration source analysis and rock engineering support design, where the interactions between the two deserve further study. In this paper, a FEM based numerical investigation on high-amplitude stress wave attenuation and rock damage evolution in one-dimensional rock bar is performed, aiming to understand the interaction between the variation of rock damage and wave attenuation. The numerical model is calibrated by experimental results. The spatial distribution of damage in rock bar is quantified by statistical windows. The effects of wave amplitude and heterogeneity index of rock on wave attenuation as well as the distribution of damage are analysed in details. The results indicate that the high-amplitude stress wave decays exponentially in the rock bar, and the attenuation of wave becomes significant as the incident wave amplitude increases. The incident wave amplitude corresponding to the lower limit of the amplitude effect is approximately 30% of the static compressive strength of rock, while that corresponding to the upper limit is the dynamic compressive strength of rock. Under the same incident wave amplitude, the attenuation of stress wave is more obvious in the rock with higher heterogeneity. The rock damage is quantified in a specific window, and its spatial distribution is described along with the movement of the window. The rock damage is concentrated in a region near the incident end. The damage development in space is consistent with that of high-amplitude stress waves and is more obvious in the models with higher heterogeneity. Findings in this work is helpful for the understanding of interaction between high-amplitude stress wave attenuation and rock damage and facilitate design and protection of rock engineering.