Analysis on Strata Behavior Law and Study on Support Selection of High Mining Height Working Face

According to problem of support selection in fully- mechanized shallow coal seam face of Shendong Mine, taking No. 301 workingface of Lijiata Mine as a study object, the theoretical analysis and site observation method was applied to analysis on support working re- sistance, support applicability, periodic weighting an d overburden strata movement law. Analysis results showed that roof couldnOt form the stable masonry structure, while would form the sliding instbility step beam stru cture, based on the conclusion, the paper established a mechanical model of support and step beam structure. By means of calculation, selected two- legs hydraulic su pport, its yield pressure was 9 600 kN, setting load was 7 145 kN, bore of leg was 380 mm.