An experimental study of the effect of injecting water and freezing on mechanical properties of outburst-prone coal seam

A new outburst prevention method based on injecting and freezing, considering of the important role of gas pressure and the mechanical characteristics of coal in the sprout and occurrence in the coal and gas outburst, was put forward in this paper. The curves of stress and strain with different freezing temperatures were drawn, and the effects of the water content, compaction force as well as freezing temperature on mechanical properties was discussed, through the experiment on the outburst-prone coal seam injected frozen water. It was found that the uniaxial compression strengths of coal obviously rise, its Young's modulus show a rise tendency,, and the effective stresses of gas-filled coal obviously rise and its strengths is further improved after the gas pressure falls with the freezing temperature decreasing.