Roof Structure Analysis and Determination of Supporting Strength for Close Seam Group

The 16^# upper and 17^# coal seam of Liyan Coal Mine is close thin seam group, under the influence of coal mining in 16^# coal seam, the roof stress environment and structure of the 17^# coal seam has been changed. In order to support the roof of 17^# coal seam, the numerical simulation and theoretical calculation is used to analyze the coal roof movement laws of the 17^# coal seam, and finds that the roof structure of working face is changed from beam structure to arch structure. With the Hawk-Brown's strength criterion and state equation, the tensile strength after the basic roof rock is destroyed and the reasonable supporting strength of first weighting and periodic weighting is got. Based on the determine of support working resistance, support selection is made, the ZY3200/07/13 type support can meet the requirements of roof control of 17304 working face well.