Speace-time Predictionf Model Research Of Mining Subsidence Based On Hierchincal Transfer Principle

Large scale mining of underground coal resources may cause or bring out hazards ofgeological environment such as ground subsidence, fault, fracture of the ground, not onlyseriously endangered the local natural environment, but also caused huge economic losses tothe local people and mining production.The prediction of mining subsidence is helpful to takeproper measures to control surface movement and subsidence , and is very important torecover and improve the post mining environment in the area.At present, there are manymethods of analyze the problems of ground displacement, but there is still large errorsbetween estimated results and the measured value due to insufficient knowledge of miningsubsidence mechanism and the surface deformation caused by Underground mining,determination of the parameters and so on.Based on hierarchical transfer principle, this article established a new type of groundsubsidence and deformation model by using the key strata theory and probability integralmethod after comprehensively analyzed the deformation characteristics of the overlying strataand the main control factors resulting from mining subsidence,and deduced the formula ofslant, curvature, level movement and level distortion based on the model. After that,considering the Knothe time functions, the subsidence prediction model of time and space dueto underground mining was deduced out,and the methods of the various prediction parametersin this model were also found. Under the situation of sub-critical extraction, the articleintroduced the relationship between the working face length and the first weighting stepdistance to calculate the length of the stacked layer fault block, making the model parametersbe more reasonable and accurate.Combined with practical examples of Dafosi coal mine of shaanxi province to validatethe new prediction model, and used software matlab to solve the formed model in the process of calculation.The results show that the most relative error of the model built in this work is32.54%, the average relative error is 10.36ï¼…. the most relative error of conventionalprobability integral method is 99.90ï¼…, the average relative error is 41.14ï¼…. It proved that themodel built in this work is feasible, and the effect of the model is better than the expectedresults of conventional probability integral method. Then apply the space-time model built inthis work to the first coal face 40301 in Dafosi coal mine to analyze the mining subsidence asthe working face proceed to 490m, 581m, 672m, 700m and 100 days after stopping mining,by this way, the feasibility of the constructing space-time model is being proved.