Static and dynamic mechanical properties and macro-micro coalburst prevention mechanisms of water-immersed coal
WANG Aiwen
FAN Dewei
PAN Yishan
DAI Lianpeng
LI Chaoran
YANG Kailei
ZHANG Wei
LIU Xingfa
LIU Hanqi
LU Chuang
Abstract：Hydration weakens the macro-mesoscopic mechanical properties of burst-prone coal,enhances the stress wave energy reflection-refraction capability of the coal,and reduces the risk of impact energy release in water-injected roadways.To investigate the energy evolu-tion mechanism of burst-prone coal under hydration,uniaxial compression and impact loading tests at different moisture contents were conducted.Based on energy principles,the static and dynamic energy evolution laws of burst-prone coal with varying moisture contents were analyzed.Scanning electron microscopy(SEM)and X-ray diffraction(XRD)were used to detect the fractal characteristics of rough-ness and elemental composition on the impact fracture surfaces of burst-prone coal,revealing the influence of moisture content on the roughness of mesoscopic impact fracture surfaces and mineral element content.The mechanism of water-induced crack propagation and coalburst prevention in burst-prone coal under impact stress waves was discussed.Results show:①From dry to saturated states,the num-ber and tortuosity of failure cracks in burst-prone coal under static-dynamic compression increase,with reduced brittleness and signific-antly enhanced ductility and plasticity.Strong burst-prone coal exhibits more intense failure and fewer cracks compared to weak burst-prone coal.②Increasing moisture content weakens the elastic strain energy accumulation capacity of burst-prone coal under static and dy-namic loading,reducing the total released energy.Under impact loading,the reflected energy ratio of weak burst-prone coal increases from 55%to 70%,and the transmitted energy ratio decreases from 9%to 3%;for strong burst-prone coal,the reflected energy ratio increases from 24%to 50%,and the transmitted energy ratio decreases from 40%to 10%.③Enhanced hydration causes the roughness and fractal dimension of fracture surfaces in burst-prone coal to decrease,weakening the energy consumption of local mesoscopic crack generation.Consequently,at the same impact kinetic energy,the number of impact cracks in burst-prone coal increases,creating more reflection and refraction paths for stress waves in micro-cracks.Impact energy rapidly attenuates through reflection-refraction,ultimately reducing the risk of impact energy release.
Keywords：coalburstburst-prone water-immersed coalenergy evolution lawimpact fracture surfaceroughness and fractal character-istics
Publication Date：2025-09-30
Online Publishing Date：2025-10-22(First online date of this platform, not the publication date of the document)
Pages：18( 78-95 )