Study On Deformation Monitoring Data Analysis And Surface And Overburden Movement Law Of Deep Strip Mining

With the rapid development of China's economy,people's demand for coal resources is increasing,and some mines have entered the stage of deep mining.The deformation law of surface and overburden in deep mining is obviously different from that in shallow part.Therefore,it has important theoretical and practical significance to study the prediction method and subsidence law of deep mining.A prediction method for surface subsidence in deep mining was constructed in the paper based on the research background of a mine in Shandong Province.Based on theoretical analysis,field measurement and numerical simulation,the law of surface and overburden movement in deep mining was studied,which provided technical methods for prediction of surface subsidence in deep mining.Main work and achievements are as follows:(1)Based on the measured data of surface movement and deformation of deep strips mining in a mine in Shandong,the theory of wavelet threshold denoising was used to denoise the ground moving measured data.On the basis of fully understanding the importance of chaotic prediction model,the method of obtaining two important reconstruction parameters was analyzed.Some improvements of the original algorithm were made,and the accurate and fast solutions of the two reconstruction parameters were realized.(2)According to the reconstructed parameters,time delay and embedding dimension,the chaotic characteristics of the time series are determined by the small quantity method.Finally,the weighted first-order local prediction model and the RBF neural network prediction model were established.The results showed that the prediction accuracy of the RBF neural network prediction model was superior to that of the weighted first-order local prediction model.(3)Based on the geological mining conditions of a mine in Shandong Province,the surface deformation values of different mining schemes were simulated by FLAC30 software.According to the numerical simulation results of each scheme,MTLAB was used to obtain the functional relationships between maximum subsidence,maximum horizontal displacement and subsidence coefficient and mining thickness,mining length,mining width,mining depth,different mining width,retaining width and depth-thickness ratio,using the method of regression analysis.FLAC3D software was used to simulate and analyze the vertical stress distribution of overlying strata in different numbers of strip mining working faces and the sinking values of different layers of overburden when the working face was propelled by different lengths.Results showed that the stress value increased gradually with the increasing of strip mining.As the length of the mining face increases,the amount of overburden sinking increases.With the same propulsion length,the sinking of the rock formation closer to the goaf is greater.(4)Considering the intrusion of magmatic rocks in the overlying strata in a research area of Shandong,the key layer identification was first carried out for the intrusion area of magmatic rocks.Then the key layer theory was used to numerically simulate the surface movement law of magmatic rock based on the regional stratigraphic combination and mechanical parameters.It is concluded that the surface subsidence value of the magmatic rock intrusion area was smaller than that of the non-magmatic rock intrusion area under other same conditions.The research results in this paper profoundly explain the surface and overlying movement laws of deep strip mining,which lays a foundation for the safe mining of mining areas.