The layout of drill hole and the determination of parameter in advanced water injection to prevent rockburst from occurring

The previous water injection into coal seam was applied when the tunnel was digged in order to solve the rockburst problem of Muchengjian Mine.The single drill hole isobaric water injection was put into effect on site in 6178 digging working face of this coal mine and the water increment around the drill hole was measured, then the model parameter was inversed by using variable-tolerance-band optimization search method and the water transmission and storage characteristic parameter was obtained, which showed that this coal seam had bad water transmissibility and belonged to low-wetted saturation, so the high-pressure (9～12 MPa) water injection suited it.The dynamic changing process of water injection under different kinds of pressure was described by numerical simulation in detail.The dynamic variable relation among pressure-time-wetted perimeter of water injection was formulated.The changing relation between the layout of single,double drill hole and water injection parameter was analyzed.The method of water injection using double drill hole and scheme which adopts double digging woking surface,that is water injection and digging are carried out alternately, which not only enlarges the wetted zero but also water injection does not affect digging work .The reasonable water injection parameter was also presented.