Research and application of high gas coal seam air leakage control technology based on polymer material cross-linking mechanism

Abstract In order to alleviate the problem of corner gas accumulation caused by air leakage in goaf of high gas coal seam. The rapid film-forming sealing material for the corner wall and the grouting sealing material for the corner roof were developed and optimized, and the' plugging-injection' combined air leakage sealing scheme was proposed. The orthogonal experiment was designed with the thickness attenuation ratio of the plugging film at 12h and24 h, gel viscosity, adhesion, setting time and other factors as indicators, and the best material ratio was selected. The engineering test shows that: (1) 1.5% sodium alginate solution and 7.5% calcium chloride solution can be sprayed in turn to quickly form a plugging film and stick to the corner wall; (2) 2.5% polyvinyl alcohol, 0.6% borax and 0.5% thickener were mixed into water and stirred to obtain polymer plugging slurry. (3) According to the monitoring results, the gas concentration of each monitoring point decreased by more than 62% after using the plugging material, and the gas concentration in the upper corner decreased by 67%. The air leakage decreased by more than 50%, and the upper corner decreased by 57%. The air leakage plugging scheme formed by the dynamic combination of the functions of the above two types of optimized new materials can effectively reduce the gas accumulation in the corner caused by air leakage in the goaf and reduce the occurrence of gas overrun accidents in the working face, which has a good utilization prospect.