Research on Destroyed Floor Depth ---The Example of the 51302 Working Face in the Liangzhuang Coal

Abstract Based on the analysis on factors affecting floor depth, mining depth, dip angle of coal seam, mining thickness, dip length of working face, damage variable of floor strata and whether there are faults and crushed zones in the working face are defined as main influence factors. The classical Down Three Zone Theory, Down Four Zone Theory based on damage mechanics, formula written in the national standard, BP (Back Propagation) neural network algorithm considering various influencing factors and Numerical Simulation Method were applied for predicting floor depth of the 51302 working face. A double-side seal borehole water injection device was used to determine the actual floor depth of the 51302 working face. By comparing the prediction results with the actual measurement results, the prediction results obtained by considering rock damage are closer to reality.