Study On Prediction Theory And Application Of Surface Residual Deformation Over Old Goaf

The surface residual deformation in goaf is an important issue on foundation stabilityevaluation, and residual deformation is major factor affecting the stability of goaf. Surfacemovement duration T=2.5H0(d), generally3to5years, in China’s current regulations.Observations have shown that, the goaf is not completely stable, surface movement anddeformations are likely to generate further. New buildings on the goaf, due to combined effectof additional load and disturbances, original mechanical balance is broken, the surface willproduce residual deformation, and even produce sudden subsidence in the role of externalforces. Since there were no concepts of residual deformation in current regulations, therefore,study on residual movement and deformation has important theoretical and practical value.Through overburden strata movement distortion analysis to explore the mechanism ofresidual movement and deformation, discovered the rock compaction characteristics weredifferent from the boundary of goaf to the central area. Surface residual deformation isstructure evolution process which voids, not fully compacted areas are fully compacted,caused by rock creep and other factors like new buildings, earthquake, falling groundwatertables. Due to cantilever effect of overlying strata in border area, potential maximum residualmovement and deformation are generally located in the border area. The old goaf is dividedinto two areas, border area and central area, equivalent to mining thickness, and appliedProbability Integral theory to form residual movement and deformation prediction model overold goaf, influence function included residual subsidence, the residual horizontal movement,the residual tilt deformation, residual horizontal deformation and residual curvature. Toachieve the dynamic analysis of residual subsidence, according to rock creep characteristics,applied Kelvin model to constructed residual subsidence function with the time course.According to the established residual deformation prediction model, to program residualdeformation prediction program with MATLAB. Application engineering examples and numerical simulations to carry out prediction model verification. And analyzed foundationstability in Hegang Goaf proposed projects Hexie district.