Split Hopkinson Pressure Bar Experiment and Distinct Element Research on Frozen Soil under Passive Confining Pressure

Frozen soil is a common geological material, and blasting engineering and infrastructure construction are often conducted on cold regions. However, it is difficult to experimentally analyze crack development and quantify the evolution of damage in frozen soil that has been simultaneously subjected to axial impact loading and passive confining pressure. Thus, this study quantitatively evaluated the fractures and evolution of impact damage in frozen soil under passive confining pressure using numerical simulation. The Split Hopkinson Pressure Bar was used to conduct an impact experiment on frozen soil under passive confining pressure. Subsequently, numerical simulation modeling of the impact experiment was established using Particle Flow Code 3D and Fast Lagrangian Analysis of Continua 3D. When the frozen soil was simultaneously subjected to passive confining pressure and impact loading, the position and number of cracks were analyzed based on the results obtained numerically. The model and contact parameters could predict the mechanical response of the frozen soil. The evolution of the impact damage with strain in the frozen soil was found to agree with the Weibull distribution. Furthermore, the impact damage in the frozen soil was extremely low even during the initial stage of plasticity, and the strain threshold of the damage was 0.5%.