Experimental Investigation of the Non-Darcy Equivalent Permeability of Fractured Coal Bodies: The Role of Particle Size Distribution

The permeability of crushed coal bodies plays a bottom neck role in seepage processes, which significantly limits the resource utilisation. To study under pressure, particle size distribution body grains is quantitatively considered by fractal theory. In addition, parameters percolation characteristics are calculated. Moreover, during recrushing determined dimension and porosity. A lateral limit compression test with was carried out to illustrate effect porosity on permeability, compressive fractal–permeability model proposed combination non-Darcy equivalent permeability. results show (1) migration loss fine particles lead rapid increase body. (2) Increases effective stress cause decrease. When decreases approximately 0.375, its undermined. (3) change pore structure enhance properties skeleton, causing sudden changes. (4) At low porosity, k slightly larger than ke. Thus, experimental data an acceptable agreement present model. fractal–percolation for pressure provides solution effectively determining grain bodies. research can contribute formation more fractal-seepage theoretical models fractured lithosphere, karst column pillars goaf, provide guidance mine water disaster prevention.