Damage characteristics and energy evolution law of rock-cemented backfilling combination under uniaxial compression

Abstract

To investigate the mechanical stability and energy evolution of roof-cemented backfilling-floor composite structures (RCFs), this study employs AE monitoring and FDEM numerical simulation to analyze the damage and energy characteristics of RCFs under varying the dip angle of rock-backfill interfaces (DA), roof-to-floor height ratio (RFR), and equivalent height of backfilling (EHB). Key results show that dissipated energy density sharply increases at 0.7–0.9 times peak stress, a critical threshold for RCFs transitioning from elastic energy storage to plastic dissipation. After entering the elastic strain stage, the damage variable grows exponentially with strain: increasing DA and EHB retards damage and enhances plasticity, while RFR induces a typical “M”-shaped variation. FDEM simulations reveal nearly all input energy (E_t) converts to strain energy (E_s) pre-peak, with kinetic energy (E_k) increasing progressively post-peak. Experimental strain energy (U) at peak stress is consistently lower than simulated Es, as the model fails to fully account for inherent micro-defects and interface meso-heterogeneity. Microcracks are concentrated at 50°130°, predominantly oblique shear, tensile-shear, and tensile cracks, with the cemented backfilling as the core crack initiation and propagation zone. This study provides theoretical and technical support for roadway layout optimization and stability evaluation of backfilled areas in related mining practices.

Keywords

RCFs / energy dissipation law / acoustic emission energy / damage variable / FDEM numerical simulation

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