Protection against outburst mechanism of hydraulic extrusion measure in the front of coal road heading face

Through theoretical analysis, experiment on site and numerical simulation, the characteristic of goal-water-gas system was analyzed during injecting water, and the mechanics properties, stress and strain state of coal and quantity of gas emission were studied. The research results indicated that it is the protection against outburst mechanism of the measure that elastic potential of coal is slowly released, zone of stress concentration is moved forward, length of stress relief zone is increased and the quantity of gas emission is reduced after injecting water.