Study on the Mechanism and Response Law of Fracture Movement on the Super-High Position Hard-thick Strata

Abstract

Based on the breaking of hard-thick rock strata in Ordos area triggering large-energy and strong earthquake, a thick plate structural mechanical model of breaking hard-thick rock strata is established. And the evolution process of hard-thick rock strata are analyzed based on Vlasov theory. The large energy mining earthquake and surface subsidence data are used to verify the analysis. The following conclusions were drawn: (1) The hard-thick strata in the cretaceous system will not be broken during the advancing and mining process of the 221 upper 03 working face of Shilawusu coal mine. (2) Before the advancing of the 221 upper 03 working face reached "double square", no breakage occurred in the lower part of the hard-thick strata, because no separated space was formed. (3) When the 221 upper 03 working face was advanced to about 856m, vertical "O-X" breakage occurred in the hard-thick strata. As the working face continues to advance 138m, periodic breakage will continue to occur in the hard-thick strata. (4) No large-energy mine earthquake event has occurred during mining at 221 upper 03 working face, and the amount of surface subsidence is approximately 200mm. (5) In the mining at 221 upper 03 working face, two large energy mining earthquake occurred in 837m, 1153m away from the open-off cut, respectively, and the maximum amount of surface subsidence increased to 1397mm, which basically accords with the results of the first and periodic breaks calculated by theory. The research results of this paper are of guiding significance for the study of the breaking law of hard-thick strata under similar engineering geological conditions and disaster pre-control.