The energy evolution and constitutive model of layered rock at medium and high strain rates

Abstract

This paper investigates the energy evolution and damage mechanical properties of layered rock at medium and high strain rates. Firstly, the dynamic compression experimental results of four types of rock samples were carefully analyzed to reveal the energy evolution mechanism of the layered rock. Then, a damage variable of the layered rock was defined based on the basic principle of energy dissipation. Finally, a damage constitutive model was proposed by combining the damage variable with different stage characteristics. The results show that the energy evolution mechanisms of different layered rocks are almost similar and the corresponding curves can be roughly divided into four stages. As the inclination angle of bedding plane increases, the energy storage limit develops in a “V” shape. The initial damage and the whole damage process of the layered rock can be characterized by the defined damage variable. The proposed damage constitutive model can well describe the nonlinear behaviors of the layered rock in the compaction stage and the post-peak failure process. The relevant parameters have clear physical meanings and are easily obtained from experimental data. This study can provide a theoretical guidance for the safety and stability analysis of underground rock mass engineering under dynamic disturbance.