Experimental investigation of gas desorption law of loaded raw coal

To investigate the gas desorption law of loaded raw coal,raw coal samples were used as experimental subjects. The gas desorption experiments were carried out with raw coal samples under tri-axis loading conditions at a constant temperature 30. The gas desorption law of raw coal samples℃,which were tested during the process of loading-absorption-desorption-reloading until destruction was obtained by using the self-developed coupled thermo-hydro-mechanical system. The results showed that the desorption law of loaded coal can be described by the desorption mathematical model of particle coal. The desorption amount of loaded raw samples decreases with the axial-pressure under constant temperature and confining pressure. However, the gas desorption amount increases significantly when the axial-pressure is over the peak strength. The gas desorption and migration velocity shows linear decrease with the axial-pressure during the stage of compaction and linear elasticity, and exponential increase in the yield stage and peak stage. The results have some theoretical significance for gas drainage and the study of the mechanism of gas outburst.