Study on Overlying Strata Structure Form of The Fully Mechanical Top-coal Caving with Soft Coal and Thick-Hard Roof

The destruction and caving of overlying strata of the sub-level caving mining face with soft coal and thick-hard roof, is a complex mechanical process. Correct understanding of its activity rhythm and structure form is the precondition of safety Fully Mechanical Top-coal caving, as well as based for further research on ground pressure controlling. According to the specific geological conditions, Through analyzing the overlying strata structure form of the fully-mechanized sublevel caving face with soft coal seam and thick-hard roof using theoretical analysis of mechanical model and field measurement method, the conclusion could be drawed that 'compound beam structure is formed in the upper immediate roof,because that there is a number of the small scale and strength pressure on the stent before periodic weighting. It provided theoretical foundation for safety and efficient mining.