Study On Catastrophe Mechanism For Roof Strata In Shallow Seam

Coal subterranean mining is engineering action in complicated geologic space, wall rock, especially roof stratum structure is different because of sediment entironment and geologic evolvement. Shendong coalfield is representative shallow seam for thin bedrock and thick unconsolidated layers above the roof. Longwall mining is our and Europe's main mining means.With Shendong coalfield exploitation, shallow seam longwall mining's weighting problem will be evidence.Someone says"the 19th century is bridge, the 20th century is high-building, the 21th century is humankind exploiture subterranean space".So 21 century's mine weighting study and practise will hold a wider stage and exert the important function.The condition of thin bedrock shallow seam especial stratum, the working face bring strong mine weighting; bedrock roof key stratum status and load thickness's change will have important influence for working face roof strata's stability. Roof's the initial weighting and the periodic weighting theory of traditional based on material mechanics"Guzhi-beam"and Winkler"elasticity groundwork half infinity beam"have not relate to bedrock roof breaking subsidence course for breaking mechanism study, so it difficult to judge roof after breaking and balance estate's stability. Working face actual data and academic result are unconformity.This paper based on shallow seam bedrock roof's character, prehuman study's base, physics similar simulation experiment's study, to analyse roof key stratum initial and periodic breaking's not stability mechanism and breaking rule by using theory of initial post-buckling. Consequently, we find the roof key stratum's breaking span and final subsidence's effective method for determining initial and periodic weighting. The theory result of using this method and actual data are very adjacence, it is definite significance for next studing roof strata in shallow seam dynamic and mine weighting theory.