Research On Analysis Daqing Limestone Main Roof Movement Form And Mine Ground Pressure Law Of Wannian 9#coal-seam

Although the coal industry in China has not yet out of winter period, but the annual consumption of more than 3.5 billion tons of coal in our country, whether now or in the coming decades, still there would be no new energy shake the status of coal.So the new technology of coal mining, improve the safety of coal mining, is still the important topic in front of China’s coal science and technology workers.Strong limestone roof in mining area development in Handan and Xingtai mine lot, This type of roof with caving step distance appeared to pressure big, strong, with a certain degree of percussive ground pressure, and the roof is bigger also, the water content of the safe production of coal mining face a threat.So find out the hard roof movement form and motion law, to guide mine production, improve the operation safety of great significance.this paper takes hebei central energy fengfeng mining group mine 13902 working face in ten thousand as an example, through the theoretical calculation, analysis of downhole pressure data and discrete element(state) numerical simulation technology, determine the 9 # coal seam in ten thousand the old top big blue limestone form of exercise and the regularity of underground pressure, for after the layer of coal mining work provides strong technical support.Through analysis we draw the following conclusions: 1. Through theoretical calculation and in combination with the practical situation of working face, big blue limestone main roof to belong to pressure level is not obvious;2. Old first weighting interval of 40 m, periodic weighting interval of 25 m;3. The main roof cycle to pressure strength can reach 3500-4000 kn, close to or more than 3700 kn stent safety valve open value, thus causing the relief valve opening is frequent, from now on you can see the face support selection is not reasonable;4. The article analyses the reasons of the main roof pressure continues to larger, mainly lies in the old roof rock fracture after together without caving, larger downward in the direction of friction force between rock before and after.