Research on height prediction of “two zones” of overburdcn based on BP neural network in Wuyang Mine

In order to study the variation law of the height of the pressure relief zone of the overlying strata after mining in Wuyang Mine, the BP neural network prediction analysis method was used to control the mining method of the “two zones” height. The mining method, working face length, working face advancing speed, coal seam dip angle, overburden property, mining height and other fracturing factors were used as the input layer, and the caving height and fault height were used as the output layer. With the help of MATLAB6.x neural network toolbox, the BP neural network structure of “two zones” height was constructed. After the initialization of BP neural network model, the training and testing of BP neural network model, a reliable BP neural network prediction model of “two iones” height was established. By comparing this model with the classical prediction model abroad,it is concluded that several foreign calculation methods have relatively large errors. The BP neural network prediction model of “two zones” height has the advantages of high prediction accuracy and strong applicability because of its nonlinear function approximation characteristics, which makes up for the defects of other methods. Taking No.3 Coal in Wuyang Coal Mine as the research object, the BP neural network prediction model was used to predict the height of “two zones” under various mining environments. The predicted results are basically consistent with the actual measured results. It is concluded that the change of mining method affects the change law of “two zones” height. Under specific mining method conditions, the height of “two zones” is positively correlated with mining height, and the growth rate tends to slow down; the unloading ratio is negatively correlated with mining height; the length of working face is positively correlated with the height of “two zones” and the unloading ratio, and the correlation is not affected by the mining method. Regardless of the mining method, the advancing speed of the working face is negatively correlated with the height of “two zones”, and the advancing speed and the height of “two zones” decrease linearly with a gradient of -2.4～4.2 m/(m·d-1). When the advancing speed increases to 4 m/d, the height of “two zones” is almost unchanged, indicating that the propulsion speed is the restraining factor of the hight development of “two zones”. The research results provide important technical guidance for comprehensive control of gas in Wuyang Coal Mine.