Research On Unstability And Its Control Of Roof At Large Section Mechanized Workings In Steep And Thick Coal Seams

The safety and efficiency of mining and the environmental protection of coal energy are common concerns in western mining area.There are large numbers of extremely steep and thick coal seams in Xinjiang,the most northwest province in China.The research on the roof of fully-mechanized face of large section instability is a major factor to realize disaster control and safety mining.Focusing on disaster of roof of fully-mechanized face of large section at extremely steep and thick coal seams,this paper analyzes the characteristics of disasters in overlying strata and adopts surface filling to control disasters at extremely steep and thick coal seams.By the application of engineering investigation,this thesis has a comprehensive understanding of the characteristics of coal strata occurrence,factors of spatial distribution characteristics of coal rock and indexs of disasters.With physical simulation,the paper presents the changing characteristics of stratified disturbance over time.By 3D of FLAC calculation,the paper compares and analyzes the distribution characteristics of coal and rock stress over time and mining depth as well as the change rules of before and after surface subsidence.Considering the environmental and scale effect of optimization scheme at surface filling,this paper uses GPR for status analyzing and effect evaluating.The verification shows two aspects.Firstly,fillings and caving of roof blended will make no caving at fillings and roofs;secondly,fillings and roofs can cave along the release of top-coal.Strata control ability has been improved significantly.Focusing on rule disaster of roof of fully-mechanized face of large section and control disaster at surface filling,this study has great practical necessity and scientific values.