Simulation analysis and experimental verification of dynamic mechanical properties of white sandstone based on different constitutive models

The dynamic mechanical properties of deep rocks are critical to understanding geological processes and optimizing resource extraction. Accurately understanding the dynamic mechanical properties of deep rocks not only provides insights into the geological processes and evolution of the earth’s interior, but also offers a theoretical basis for the effective extraction of deep minerals and energy. In this study, the dynamic mechanical behavior of white sandstone from a coal mine was experimentally and numerically analyzed under uniaxial, biaxial, and triaxial stress conditions. Numerical simulations based on three constitutive models consisting of the Riedel-Hiermaier-Thoma (RHT) model, the Holmquist-Johnson-Cook (HJC) model, and the continuous surface cap model (CSCM), were validated by using experimental results from three-dimensional Hopkinson bar experiments. The results indicate that the shear failure damage of white sandstone specimens decreases with the increasing prestress, with triaxial stress conditions yielding significantly lower damage than uniaxial or biaxial conditions. Among the three models, the RHT constitutive model demonstrates the closest agreement with the experimental results in terms of stress waveforms, peak stress, peak strain, and damage degree. Compared with the experimental data, the RHT model exhibits a stress peak deviation ratio of 3.5% and 13.6% for the reflected wave under uniaxial and biaxial conditions, respectively, while the stress peak deviation ratio for the transmitted wave is the lowest. Additionally, the peak stress and strain values predicted by the RHT model are numerically closer to the experimental results. The damage state predicted by the RHT model also aligns well with the experimental observations: under uniaxial loading, the damage exhibits a U-shaped pattern, whereas the HJC model showed a larger V-shaped damage pattern and fracture, and the CSCM model displayed surface damage with a smaller affected area. In terms of energy absorption and dissipation, the simulation results based on the three constitutive models shows minimal differences. The incident, reflected, and transmitted energy values are nearly identical across all three models. In addition, the damage degree of the white sandstone specimens increases with the impact velocity. The damage simulation results of the three constitutive models also show an increasing trend with the impact velocity, while retaining the damage characteristics.