A non-Darcy compressible gas-solid coupling model for rock blasting and its application

Understanding the fracture mechanism induced by blasting gas pressurization is essential for rock engineering. This study develops a coupled gas–solid model within the finite–discrete element method (FDEM) to simulate blasting gas–driven crack propagation. The model incorporates gas compressibility and inertial effects, overcoming limitations of traditional FDEM coupling schemes and improving the accuracy of blasting gas penetration. Validation against analytical solutions for one-dimensional (1D) transient compressible flow and CO 2 blasting experiments confirms the model’s reliability. The coupling scheme is further integrated with the Jones–Wilkins–Lee (JWL) equation of state to capture the combined action of stress waves and blasting gas. Results indicate that stress waves mainly enlarge the crushed zone, whereas blasting gas plays a dominant role in extending primary cracks and expanding the fracture zone. Stress waves govern the peak particle velocity (PPV), while the contribution of blasting gas remains limited, generally below 15%. Finally, a modified PPV prediction model incorporating gas pressure is proposed, establishing a quantitative relationship among PPV, charge, distance, and gas pressure.