Surface Subsidence Prediction Method Of Overburden Isoation Grouting Filling Mining

The overburden isolation grouting filling mining technology has the advanta ges of high coal mining rate,low filling cost,small mutual interference betwee n coal mining and filling,and is an important method to solve the problem of coal mining under buildings.Accurately predicting the subsidence prediction of t he filling method is very important for the design,effect prediction and evaluati on of the filling project.However,the traditional surface subsidence prediction method does not consider the influence of overburden grouting horizon and gro uting filling distribution on rock stratum and surface subsidence,and is not suit able for surface subsidence prediction under overburden isolation grouting and fi lling conditions.Aiming at this problem,several methods,theoretical analysis,n-umerical simulation and field measurement,were adopted to verify the prediction method of surface subsidence under overburden isolation grouting and filling c onditions.An prediction model of surface subsidence for overburden isolation grouting and filling was built.Based on the stratified transfer law of the rock movement,it was found that the rock movement could still be perdicted by the probability integral method.Firstly,the calculation formula of the sinking layer below the grouting layer was proposed through probability integral method.Then,the distribution characteristics of the filling in the overburden were determined according to the grouting filling parameters,and the calculation formula was gotten.According to the subsidence of rock stratum below the grouting layer and the thickness distribution filling body,the subsidence of the rock stratum above the grouting layer was calculated,which contributed to calculation of the surface subsidence under the condition of overburden isolation grouting and filling.Based on the established prediction methods and models,a program coded with Python was built for the surface subsidence prediction in the overburden isolation grouting filling technology.With this program,some difficulties were solved,including the division of the integration interval,the determination of the estimated step size,the determination of the grid spacing,and the determination of the boundary points of the basin.Furthermore,the program ran at a certain sequence,information processing,prediction calculation,data output,and single point,query and output verification,which could provide prediction of surface subsidence in both grouting and non-grouting filling cases.The accuracy of the proposed method was verified by the measured data of the overburden isolation grouting filling project in Huaibei Mining Area.Comparing the prediction of surface subsidence obtained from proposed method with measured data and the predicted results of the traditional method,the error accuracy of this prediction method was below 18.5%,and the deviation was also relatively small.The expected results are more accurate than the expected results of the traditional methods.The proposed method was accurate and creditable enough to meet the engineering requirement,although there were still some differences from the actual measurement.This paper contains 44 pictures,6 tables,and 105 references.