| Aiming at the problem of shearer shutdown and low starting rate caused by gas concentration overrun in fully mechanized mining face.Taking the 1306 working face of Licun Mine of Shanxi Lu ' an Mining Group as the research background,the theoretical analysis,numerical simulation and field measurement are combined and verified with each other.The comprehensive analysis of gas source and emission law,gas migration and influencing factors,and the influence of coal cutting speed on gas emission in fully mechanized working face are carried out,and the adaptive control method of coal cutting speed in intelligent working face is proposed.The following researches were carried out:(1)The mathematical model of gas emission prediction in high gas working face is established.Based on the coal mining characteristics of fully mechanized working face and the field measurement and analysis,the main sources of gas emission in 1306 fully mechanized working face are determined.The mathematical prediction model of gas emission in fully mechanized working face is established by using the source separation prediction method;Using the on-line monitoring system of mine working face,the distribution law of gas concentration in fully mechanized mining face is analyzed,and the feasibility of mathematical prediction model is verified.(2)The gas migration law and influencing factors of fully mechanized working face are analyzed.Numerical simulation method is used to study the influence of ventilation modes on gas migration;The influence of coal seam mining on gas permeability is comprehensively studied,and the variation rules of porosity,permeability and viscous resistance coefficient are determined.Through the analysis of gas migration mode under different airflow,the mathematical model of gas migration in goaf of working face is established.(3)The dynamic relationship between coal cutting speed and gas concentration time and space distribution in working face is clarified.The spatial distribution law of gas in stope is analyzed by numerical simulation method.The gas concentration in the upper corner is basically positively correlated with the coal cutting speed of the shearer and negatively correlated with the distance between the coal machine and the upper corner,which verifies the feasibility of the coal cutting speed and the follow-up control of the gas in the working face.(4)An adaptive control strategy of cutting speed in high gas fully mechanized mining face is proposed.The coal cutting speed table with feedback of gas concentration in 1306 working face is formulated,and the application effect of followup control strategy of gas concentration and coal cutting speed of shearer is tested by Fluent software.Adaptive control system for cutting speed of working face has been designed and developed to visually display the following relationship between cutting speed and gas according to basic information of working face of mine.The validity of the software is verified,and the research results can provide a reference for the control of coal cutting speed in similar mines.The thesis has 66 figures,16 tables and 102 references. |
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