| Aiming at the Tashan Coal Mine of Datong Coal Mine with mining depth and coal face yield ability, fully mechanized caving face gas emission quantity increasing situation, analyzed the existing problem of comprehensive caving working face gas control scheme of" U+I " type ventilation in upper corner gas overrun, according to the existing mine roadway and geology, in8105working face as the research background, present" W+I" type ventilation. According to the theory of flow of mine air, numerical methods in computational fluid dynamics CFD module using Comsol finite element analysis software Multiphysics, analyzed two inlet Road (2105lanes and5105roadway) the air flow into the same (scheme) and different (scheme two) two of8105working face under the condition of ventilation and gas concentration, determine the ventilation scheme and design flow. At the same time as the ventilation mode change, will be in the middle of8105working face in creating a central air return groove, groove design length476m. Since the middle of8105working face return air along the groove in the middle of8105working face, the working face is located in the region of high stress concentration due to excavation, the roadway, the stress at the center of a redistribution and superposition, making in stope and central return air lane at the intersection of the surrounding rock stress distribution is very complex; by mining dynamic pressure effect, make the intersection roadway supporting is complicated. How to ensure the stability of the mining process of the tunnel is the premise of8105working face safety production. Therefore, in this paper, mine provided roadway and support parameters on the basis of analysis, stress distribution and displacement of surrounding rock and failure characteristics of middle8105 working face return roadway surrounding rock, put forward reasonable roadway supporting methods and support parameters based on the original roadway support parameters. The main results include the following three aspects:One, through the analysis of the8105working face ventilation mode, the three major factors influencing the working surface gas overrun:one is gas instantaneous thick coal seam fully mechanized top coal caving mining technology with high intensity transient coal caused by large volume of the flood; two is the caving coal process causes a disturbance resulting from the goaf gas overflow the mined-out area; three is a gas of working face pressure will be the accumulation of goaf extrusion to working face. According to the actual situation of Tashan mine, combined with the characteristics of current various working face ventilation system more mature, we propose the following three kinds of scheme optimization, the current working face ventilation were:" W+I"," U " type," two into three ". After schemes comparison, ultimately determine the working face ventilation system with "W+I" type.Two, using the Comsol software of Multiphysics two into the airway (2105lanes and5105roadway) the air flow into the same (scheme) and different (scheme two) two of8105working face under the condition of ventilation and gas concentration is analyzed. The results show that:two conditions will make the face lane and2105, central return air lane,5105roadway intersection has a strong eddy current phenomenon, makes this gas concentration is too high, about1.2%, more than the warning value of1%, the need to pay attention to. The other part is no gas concentrations exceed the standard. Because in the second scheme2105Lane5105lane design larger air volume, pressure difference with, make and5105lane and romantic face connected with the presentation of full section strong turbulence, air flow is chaotic, the gas in the easy to form aggregates, resulting in a definite influence on the safety production of mine. It is proposed the use of ventilation scheme and design of air.Three, through numerical calculation and analysis, the central air return trough in8105working face of the most prone to failure region is the central air return way, within the range of5m, and in front of the working range of15m by including a region.8105mining influence range is in front of the50m range, so the middle8105working face return roadway must advance support distances are determined for60m. |
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