Research On Blasting-enhanced Water Injection Outburst Prevention Mechanism And Technology In Mining Face

Coal and gas outburst is one of the major disasters restricting the safe and efficient production of deep mines in China.The outburst coal seams often have the characteristics of short pressure relief zone and dry coal seams.In order to eliminate the risk of coal seam outburst and increase the length of pressure relief zone,an integrated outburst prevention method of blast-injection integrated?BII?technology is proposed.Aiming at the hidden dangers of explosives in the blasting hole and the difficulty of injecting water into the blasting hole,the BII of sealing technology and equipment has been developed to achieve safe and efficient operation of explosives,water seal blasting and water injection in the sane holes.In this paper,the author first studied the mechanism of eliminate outburst of loose blasting under the action of mining stress field by means of numerical simulation,and optimized the construction layout of the BII technology.Secondly,the laboratory experiment was used to study.After water invasion,the characteristics of coal gas adsorption and desorption after water intrusion are studied,and the outburst mechanism of water injection is expounded.Finally,through field tests,the outburst-reducing effect of the BII technology was verified again.The main research conclusions are as follows:?1?Through FLAC3D numerical simulation software research,it is found that the elastic strain energy in mining face is released after loose blasting,forming a safety zone,which effectively hinders the release of deep strain energy.Secondly,the peak value of elastic strain energy is transferred to the deep part,which reduces the probability that the stoppage disturbance triggers outburst accident.At the same time,in the effective area of blasting,the three-way permeability is significantly improved.This is not only conducive to the influx of gas from the deep mining panel to the working surface,but also lays the foundation for the subsequent water injection operation.?2?Through the self built experimental platform,the desorption characteristics of gas after water intrusion into coal body are studied.The results show that the desorption strength of water is much greater than that of water replacement.Combined with the energy dissipation law of coal and gas outburst,it is found that with the increase of water injection ratio,the gas expansion energy of coal body decreases,which significantly reduces the risk of coal seam outburst.?3?Field tests in E_15.16-24100 mining panel show that after the implementation of BII technology,the peak stress in mining face was transferred to the deep part of the coal seam by an average of 5 m;the gas emission within 30 minutes after blasting was30 minutes before blasting The gas emission volume is doubled,and the average monthly gas solubility in mining face has decreased from 0.53%to 0.37%,which is about 30.1%.In addition,after the implementation of the measures,the monthly gas alarms in the mining surface have been changed from the original 25,Basically disappeared in the later period.In addition,the monthly average concentration of total dust and respiratory dust in the return air stream is significantly reduced,which effectively improves the operating environment and reduces the incidence of occupational diseases.The above research results have laid an important theoretical and technical foundation for the rapid outburst elimination in mining face,and have great theoretical and practical significance for the future outburst prevention design.There are 44 pictures in this paper,2 tables,and 101 references.