Study on Holmquist-Johnson-Cook Constitutive Model and Numerical Simulation of Red Sandstone Based on Static and Dynamic Mechanical Tests

Rock materials are widely used in protective engineering and various civil engineering structures such as tunnels, and the research on their dynamic mechanical properties is of great significance. In this paper, red sandstone from a stone mine in Jinan, Shandong Province was taken as the research object. Triaxial testing machines and split Hopkinson pressure bar (SHPB) devices were used to study the mechanical properties of red sandstone under different confining pressures and strain rates, respectively. Based on the static and dynamic mechanical tests, the parameters of the Holmquist-Johnson-Cook (HJC) constitutive model for red sandstone were calibrated. Using the calibrated parameters of the HJC constitutive model for red sandstone, a finite element model of the SHPB dynamic compression test was established to verify the parameters. The results show that: Under the confining pressure environment, the propagation direction and extent of internal cracks in red sandstone are restricted, making it difficult for cracks to penetrate rapidly. Thus, the peak stress increases with the increase of hydrostatic pressure. Under loading with different air pressures, red sandstone exhibits an obvious rate effect. The dynamic compressive and splitting tensile strengths are positively correlated with the average strain rate. Through the research and analysis of the dynamic increase factor for compressive strength (DIF_c) and dynamic increase factor for tensile strength (DIF_t), the rate effect of the dynamic tensile peak stress is more significant. The calibrated HJC constitutive model parameters can well simulate the damage and failure process of red sandstone under dynamic impact in LS-DYNA. Before reaching the maximum peak stress, the stress-strain curves from the numerical simulation results are basically consistent with those from the test results. The calibrated parameters for dense and high-strength red sandstone in this paper can provide a reference for the research on the dynamic mechanical properties of red sandstone and its engineering applications.