Propagation and Fracture Mechanisms of One‐Dimensional Explosive Stress Waves Regulated by Cavity Structures

ABSTRACT The propagation characteristics of explosive stress waves in rock masses are fundamentally influenced by the coupling conditions between the charge and the surrounding medium. This study systematically investigates the effect of annular cavity structures on one‐dimensional explosive stress wave propagation and rock fracture behavior through a custom‐built one‐dimensional loading experimental system. Eight groups of comparative tests were carried out with decoupling coefficients ranging from 0 to 0.875, and the time‐domain and frequency‐domain responses of rock specimens were obtained via ultra‐dynamic strain measurement, digital image correlation (DIC), and Hilbert–Huang transform (HHT). The results show that rock fracture patterns evolve through four stages with increasing decoupling coefficient, and a critical decoupling coefficient of 0.75 is identified, corresponding to the most significant asymmetric spalling effect. Frequency‐domain analysis indicates that the cavity structure acts as a mechanical filter, suppressing high‐frequency components (30–80 kHz) while enhancing low‐frequency energy (below 20 kHz), which transforms the loading regime from impulsive shock to combined impact‐quasi‐static gas expansion. This study establishes the correlation between spectral evolution and fracture mechanisms and provides theoretical support for the optimization of decoupled charge designs in rock blasting engineering.