Abstract:
Taking 14201 double-decked hard roof working face in Majialiang Coal Mine as an example, the similar simulation experiment and ground pressure observation are carried out. The first pressure step of the upper hard roof is 106 m, the periodic weighting is 50 m to 60 m, the first pressure step of the lower hard roof is 60 m, the periodic weighting is 20 m to 25 m. It is found that the failure behavior of the double-hard roof is presented as “the lower short cantilever beam and the upper long masonry beam” structure. The failure modes of the whole structure are the lower hard single roof collapse and the upper and lower hard roof collapse. The lower hard roof collapse forms “small periodic weighting”, and the upper hard roof collapse causes severe impact on stope and roadway rock and forms “big periodic weighting.”