The mechanism and application of high-pressure water jet technology to prevent compound dynamic disaster

In order to study the occurrence mechanism of compound dynamic disaster in roadways, the N2103 headgate adjacent to panel 2105 that belong to Yuwu Colliery is taken as a typical engineering background. By means of in situ investigation, theoretical analysis, numerical simulation, in situ tests, and relevant monitoring methods, the permeability-increasing mechanism and pressure-relief mechanism about boreholes after using water jet technology are studied. The results show that the compound dynamic disaster start-up zone is the most important zone, and a coal pillar with some confining pressure in this zone is established by FLAC3D numerical simulation software. The numerical simulation results indicate that the dynamic load plays a dominant role in the superimposed effect of dynamic and static loads under the same static load combined with different dynamic load conditions, and the dynamic load plays an induced role in the superimposed effect of dynamic and static loads under the same dynamic load combined with different static load conditions; the new boreholes with larger diameter can form a larger range of plastic zone around the borehole wall, which is conducive to further improving the permeability of the coal body around boreholes; the superimposed effect of dynamic and static loads is weakened after using water jet technology and then effectively prevents the occurrence of rock burst in roadway ribs and floor; the results of EMR monitoring, SEM observation, gas flow attenuation coefficient monitoring, and displacement monitoring indicate that water jet technology is effective and feasible for prevention of compound dynamic disaster. The study conclusions provide theoretical foundation and a new guidance for preventing compound dynamic disaster in roadways with similar engineering geological conditions.