Height ratio‑dependent creep failure of coal‑rock composites: A multi‑scale analysis integrating stepwise creep, AE monitoring, and SEM characterization
This study integrates multi-scale analyses to demonstrate that the rock-to-coal height ratio critically governs the creep behavior of coal-rock composites, revealing that a 1:1 ratio offers optimal long-term stability and identifying a consistent failure stress threshold of approximately 90% of peak strength alongside a transition from shear- to tension-dominated cracking mechanisms as rock proportion increases.