Research On Dynamic Prediction Of Spontaneous Combustion In Goaf Based On Improved CRITIC-G2-TOPSIS And Numerical Simulation

Oxidation spontaneous combustion of goaf residual coal is one of the main sources of coal mine disasters.Spontaneous combustion fire will not only cause residual gas combustion in goaf,but also cause gas explosion,which seriously threatens the safety production of coal mine.Scientific evaluation of the leading factors and development trend of spontaneous combustion risk in goaf during the dynamic advancing process of working face,and accurately grasp the temporal and spatial evolution law of spontaneous combustion of goaf residual coal,which lays the foundation for targeted prevention of spontaneous combustion in goaf,and it has important theoretical value and practical significance to ensure safe and efficient production of mine.Taking the 10101 fully mechanized caving face in Baozigou coal mine as the engineering background,this dissertation uses the methods of theoretical analysis,experimental research,intelligent calculation,numerical simulation and field test to dynamically predict the risk of spontaneous combustion in goaf,and numerically simulate the dynamic evolution law of spontaneous combustion of residual coal in goaf.Based on this,the comprehensive prevention and control technology of spontaneous combustion of residual coal in goaf is put forward.Through the layout of measuring points in the goaf of 10101 fully mechanized caving face in Baozigou coal mine,the air leakage and oxygen supply conditions,heat storage and heat dissipation environment were measured.At the same time,carry out experimental research on coal spontaneous combustion characteristics.It provides important basic data for dynamic prediction of goaf spontaneous combustion risk,and provides theoretical parameters for numerical calculation of goaf residual coal oxidation spontaneous combustion.Based on the main influencing factors of goaf residual coal spontaneous combustion,15 spontaneous combustion prediction indexes are determined,and the dynamic prediction index system of goaf residual coal spontaneous combustion risk is established.The index weight calculation model based on improved CRITIC-G2 method is proposed.Then,the updating factor is introduced to modify the model,and the dynamic weight calculation model of goaf residual coal spontaneous combustion risk prediction index based on improved CRITIC modified G2 was constructed.Considering the change of spontaneous combustion risk in goaf from dynamic scale,based on TOPSIS method,the decision model is optimized by introducing euclidean distance function,the dynamic prediction model of goaf spontaneous combustion risk based on improved CRITIC-G2-TOPSIS is established.The dynamic prediction model was applied to dynamic prediction of spontaneous combustion risk in goaf of 10101 fully mechanized caving face in Baozigou coal mine.The prediction results show that the risk level is grade ?,which is consistent with the actual situation.At the same time,the corresponding feasible prevention and control measures of spontaneous combustion are put forward.The air leakage flow field model,oxygen concentration model,gas-solid temperature field model and related boundary conditions are combined to establish a 3D dynamic multi field coupling mathematical model of goaf residual coal spontaneous combustion.The 3D dynamic goaf geometry model is established by using CFD software dynamic mesh model,and combined with the mathematical model,the simulation of 3D dynamic goaf is realized.The model can quantitatively study the influence of working face advancing distance,working face length,advancing speed and air supply on spontaneous combustion of residual coal in dynamic goaf.The variation rules of wind velocity field,oxygen concentration field,temperature field and spontaneous combustion "three zones" in the process of working face advancing were obtained under different working conditions.It provides a theoretical basis for prediction of residual coal spontaneous combustion in goaf,the location of spontaneous combustion danger area and the reasonable determination of fire prevention and extinguishing technical parameters.According to the dynamic prediction results of spontaneous combustion risk in goaf and numerical simulation results,a comprehensive prevention and control technology system of spontaneous combustion in goaf is put forward,which is composed of "inerting and coolingcovering and oxygen isolation-plugging and controlling wind-blocking chemical inhibition".Comprehensive prevention and control measures for spontaneous combustion in goaf,which take nitrogen injection fire prevention and extinguishing technology as the main technology,combined with the inhibitor spray,gel injection and shot-off loss wind are applied in goaf of 10101 fully mechanized caving face in Baozigou coal mine.Through field industrial test,good fire prevention effect has been achieved,which provides reference for mine disaster prevention and control under similar conditions.This dissertation contains 77 figures,27 tables and 203 references.