Study On Outburst Prevention Technology Of Area In Rock Cross-cut Coal Uncovering With Ring Closure Coal Bottom Roadway

Coal and gas outburst accident is one of the main threats to the safety production of the mine, which happen in cross-hole uncovering coal not only have the highest probability but also the biggest risk. Many domestic and foreign large-scale outburst accident occurred during uncovering coal in crosscut, and caused serious casualties and property losses. Therefore, it is necessary to research cross-hole uncovering coal outburst in order to make prevention and control measures according to the situation.It used the methods of theoretical analysis, numerical simulation and field experiment in this paper, and systematic researched on the types, influencing factors and occurrence conditions of cross-hole uncovering coal outburst, drew a conclusion of there is a big relationship between coal seam gas pressure migration and the change of stress state of the coal influenced by mining moves and cross-hole uncovering coal outburst. Then the paper made a analysis about the process of outburst form the perspective of energy, obtained that the energy of promote outburst mainly include gas expansion energy and elastic strain energy, and gas expansion energy has a dominating state, elastic strain energy only crush coal and improve coal temperature in the process of outburst. Therefore, the outburst prevention and control is mainly by means of gas govern, In view of the mine situation, the coal seam belongs to high outburst seam and do not have the condition of protective layer mining, in addition there are multiple cross-hole all need uncovering the coal seam, the range of uncovering coal is very wide, so the mine adopted the annular closed floor roadway coal seam gas pre-drainage for regional outburst elimination, by means of construct two bottom plate extraction lanes with different levels and linked by coupon lanes. It can not only ensure the construction space of measures for drillings but also avoid the downward hole and horizontal hole. It can shorten the pre-pumping time and guarantee of eliminating outburst effect. Meanwhile, the paper also researched the pumping effect under different pumping conditions by numerical simulation with numerical simulation software COMSOL-Multiphysics, conducted the drilling parameter optimization through analysis and comparison, determined the effective drainage radius is1.5m, verified in the field and ensured the optimal parameters in the last, In the end, It conducted field investigation of outburst prevention technology of area in rock cross-cut coal uncovering with ring closure coal bottom roadway at multiple rock cross-cut coal uncovering of Xieyi coal mine, it proved that the coal seam outburst danger have been eliminated because of the implementation of outburst elimination measures, and ensured the safety production of entire mine during multiple cross-hole uncovering the coal, and the measures have certain application value.