Research On Forecast Updating DEM In Mining Subsidence Area

Surface morphology changes with surface subsidence which caused by undergroundmining. Mining subsidence features are generally described by two-dimensional curve or sinkcontour, which can not integrate the original and subsidence information, so it isinconvenience to describe mining area landform scientifically and analyze the dynamicchange characteristics. With the further development of the digital elevation model (DEM)theory, using DEM to overlay the original and subsidence terrain information in miningsubsidence area, may realize the forecast updating of numeral terrain information in this area.This paper studies DEM updating methods and elevation interpolation algorithms as wellas prediction model of mining subsidence, then proposes a forecast update method oftopographic map in mining subsidence area by overlaying DEM, the method is: first toforecast the quantity of surface subsidence, then interpolate the original elevation of thesinking points by the original terrain DEM, at last realize DEM update in the miningsubsidence area after overlaying two elevation files. Main research contents and results are asfollows:(1) On the basis of the analysis of DEM principle, this paper compares several basicmethods of updating DEM, in view of the current limitations of those methods, givenprediction model of mining subsidence, a forecast update method of DEM in the miningsubsidence area is proposed.(2) This paper elaborates DEM interpolation theory, and analyzes the applicability ofeach interpolation method, then chooses mobile surface fitting interpolation algorithm tointerpolate elevation and commonly used probability integral forecast model as well toforecast subsidence. On this basis, this paper analyzes the key techniques and algorithmswhich are applied in this method, and uses VB to design and program the DEM interpolationand overlay procedure, and forecasts the quantity of surface subsidence by probability integration by MATLAB which can really realize forecast updating of DEM in miningsubsidence area.(3) In view of the original elevation information extracted by the digital topographic mapin the research example, this paper selects the forecast parameters according to mininggeological conditions, and forecasts surface subsidence, at last overlays and updates digitalelevation model by the procedure programmed, the updated topographic map can be producedto directly reflect the topographical variations before and after the mining subsidence.(4) Against the DEM interpolation algorithm and probability integral forecast model, theaccuracy of elevation interpolation and subsidence forecast has been separately discussed indifferent parts of mining subsidence area, the result shows that we can improve subsidenceforecast accuracy by correcting the forecast parameters, so that it can meet the needs ofupdating technical requirements of large-scale digital topographic map in mining subsidencearea.The research in this paper has initially realized the forecast updating of DEM in miningsubsidence areas, the procedure can also be used in producing contour maps of coal seamdepth and earthwork calculation, which result can provide the technical foundation for miningGIS applications.