Damage mechanisms in loess media under blast action: insights from experiments and numerical simulations

The study of damage mechanisms in loess media induced by explosion loading possesses significant scientific value and engineering significance for engineering practices and geological disaster prevention in loess areas. This research analyzes the macroscopic and microscopic physical and mechanical responses of loess damage under explosive loading through field explosion tests and discrete element numerical simulations. Results confirm the particle expansion method effectively simulates blasting in loess strata. Charge shape significantly influences crack propagation: spherical charges release energy uniformly, generating radial damage and more fractures, while cylindrical charges release energy axially, producing a smaller damage range. Increased particle gradation suppresses crack development by enhancing interparticle friction and energy scattering, leading to shorter cracks, higher compression ratios, and accelerated stress wave attenuation. Both experimental and numerical results validate that stress wave attenuation follows Baum’s formula. Simulated interparticle stress and vibration velocity effectively explain loess damage patterns, enabling prediction of failure ranges. This study not only verifies the applicability of the particle expansion method in loess media but also systematically reveals the coupled influence mechanism of charge shape and particle gradation on loess explosion damage, providing a new analytical framework for the refined design and damage prediction of blasting engineering in loess areas.