The Study Of Surface Residual Mobile Deformation Of Old Goaf Caused By The Descend Of The Underground Water Level

Our current procedures that mining process surface movement duration T=2.5HO (d), usually for3-5years. Observation data show that after the mined-out area isnot completely stable, the surface offers the opportunity to move furtherdeformation. When old goaf ground water level change, goaf under the influence ofseepage effect after the original mechanical equilibrium is broken, the surface willproduce a residual deformation. Tectonite roof rocks in moist, dry mechanicalparameters changed under different condition, stress caused by imbalance, in underthe action of external force, even can produce sudden subsidence. Due to thediscipline does not take part in the concept of residual deformation, therefore, thestudy of residual deformation has an important theoretical and practical applicationvalue. By analyzing the goaf strata movement variation, explores falling water tablescausing movement of surface residual deformation mechanism, discovered since thecompaction characteristics of rock caving goaf border to the central district of theobvious, first proposed residual movement and deformation of surface definition andtwo stages, the second stage of the residual movement and deformation indicated itmay have a detrimental effect on surface buildings. Residual surface movement anddeformation is below the surface of new buildings, earthquake, falling water tablesand other factors affecting the interaction with the rock rheological, empty, not fullycompacted areas, more fully compacted zone overlying rock structures were fully filled and compacted evolution. Border region due to the cantilever effect of overlying rocks, empty greater activation potential of large, static residual movement and deformation maximum exploitation of the border regions are generally located. The old mined-out area is divided into central and boundary portion, respectively, equivalent to the equivalence of different mining thickness, the application of the principle to construct the probability integral old Mined residual movement and deformation prediction model deduced residual movement and deformation of the first and second stages prediction formula, including residual sink, mobile residual levels of residual tilt deformation, deformation and residual levels of residual curvature deformation.According to the established residual deformation prediction model, to program residual deformation prediction program with MatrixVB. Application engineering examples and numerical simulations to perform prediction model verification. And analyze the results and practical significance to verify the prediction formula.