Effect of water on dynamic mechanical properties of coal under different depth stress conditions

Abstract

Coal seam water injection in tunnels is an effective technical measure for preventing coal mine rock bursts. This study used the improved split Hopkinson pressure bar (SHPB) to apply three equal static stresses to water-saturated coal to simulate the initial stress environment of coal at different depths. Then, dynamic mechanical experiments were conducted on the saturated coal at different depths to investigate the effects of water saturation and depth on the coal samples’ dynamic mechanical properties. Under uniaxial compression and without lateral compression, the strength of coal samples decreased to varying degrees in the saturated state; under different depth conditions, the dynamic strength of coal in the saturated state decreased compared with that in the natural state. However, compared with that at 0 m, the reduction in the strength of coal under the saturated condition at 200, 400, 600, and 800 m was significantly reduced. The findings of this study provide a basic theoretical foundation for the prevention and control of dynamic coal mine disasters.

Keywords

coal / mining depths / water saturation / SHPB / dynamic compressive strength

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