Key Technology of Predicting Dynamic Surface Subsidence Based on Knothe Time Function

A method for calculating the parameter of Knothe time function was presented. The principle of predicting dynamic mining subsidence was discussed based to the relationship between the periodic fractures of main roof and surface subsidence. Pointed out there might be a section whose width was shorter than a mining unit when divided a workface into n equal mining elements, the section should be calculated specially in the algorithm. A model of predicting dynamic mining subsidence was made according to the Knothe time function and probability integral method. A model how to divide a workface and two coordinate transformation models among three coordinates also were made. An algorithm step of the dynamic prediction model for multi-face mining was designed and implemented. And the algorithm was tested by nine measured subsidence data in different times of some mine 1176 east face, the result showed that the prediction results agreed well with the observation data, and the feasibility and effectiveness of the algorithm were demonstrated. Finally, the process of surface subsidence and deformation of 1176 east face was back analyzed.