Influence Of Mining Velocity On Strata Movement Law At A Fully Mechanized Coal Face

In a certain period of time, coal will still occupy an important position in energy structure of China. However, due to the limitation of mining technology, the phenomenon of strata movement occurred more and more frequently in mine mining, which caused great damage to the ecological environment around the mine. Field practice showed that if the mining velocity was too fast, the deformation time of roof strata would be shorter, the roof weighting step of first weighting and periodic weighting at working face would increase, the roof pressure would increase, the support problem of roof would be serious. At the same time, it also had some influence on strata movement. At present, the effect about mining velocity of roof strata damage and strata movement had not yet been carried out in-depth and systematic exploration. This article launched the research for this field, proved the law that influence of mining velocity on the roof weighting step, ground pressure strength and the failure height of roof strata, in order to improve the theory of mining pressure and strata control, to control strata movement, to guide the coal mining practice, to provide a basis to determine the rational working resistance on working face, to ensure that the mine production was safety and efficiency. So that coal mining can develop rapidly on the premise of reducing environmental damage.This paper taken Shangwan mine of Shendong coal mine fully mechanized coal face as the research background, through combined methods of theoretical analysis and similar simulation, numerical simulation calculation and field measurement as integrated research method, analyzed the law that influence of mining velocity on the roof strata movement, the main achievement of the research were:(1)By studying the rheology mechanism of roof strata, based on the Maxwell model, established rheological mechanics model of roof rock strata of Shangwan mine, got the viscoelastic solution of cantilever rock beam and double fulcrum rock beam.(2)Analyzed the roof weighting step of roof and the law of sink age, the distribution law of lead abutment pressure at different mining velocity, which used the method of similar simulation, it was concluded that: the faster the mining velocity, the greater the periodic weighting length, the smaller the squat of the roof strata, the greater the abutment pressure peak, and the peak position was more near to the coal wall of working face, the smaller the influence scope of abutment pressure.(3)Analyzed the stress field of roof, the plastic failure zone at different mining velocity, which used the method of FLAC3 D numerical simulation, it was obtained that: the faster the mining velocity, the greater the abutment pressure peak front of the working face, and the peak position was more near to the coal wall of working face, the smaller the damage height, the destruction line of roof strata.(4)Analyzed working resistance of stent and filed research at different mining velocity. Through the method of theoretical analysis to estimate working resistance of stent at the different velocity in the periodic weighting, and calculated the limit velocity of the working face with interpolation. Finally carried on the mutual verification with actual support load and load estimated value at the same velocity, inferred that measured results and working resistance of stent at the same velocity has basically tallied, measured results and the results of similarity simulation experiment and the conclusion of numerical simulation has equated.