The invention discloses a device and method for enhancing a
coal seam fracturing effect. The device comprises four parts, namely, a connecting rod, a connecting sleeve, an expandable sleeve and a constant-
pressure switch; a drilling site is arranged according to a full mechanized mining face and
coal seam occurrence conditions, all parts are assembled into a
system in sequence according to a figure 1 based on drilling site parameters and the
coal seam occurrence conditions, the
system is arranged between two hole packers and is connected with a water injection
pipe, and then, a high-pressure water injection fracturing process is started. According to the device, the number of hole wall cracks can be increased, the device can be used for changing
hydrostatic pressure into pulse loads for injected high-pressure water, so that the crushing degree of rocks is enhanced, the crack density is increased, and the
hydrostatic pressure can be used for increasing the lengths of the cracks. The invention aims to increase the air permeability of the coal seam, solve the problem of difficult drainage in low-air-permeability coal seams, and increase the gas
drainage rate of the coal seams. The device has the advantages of simplicity, clear concept and convenience in operation.