Study On Law Of Overlying Strata Movement And Strata Behaviors At Fully Mechanized Coal Face With Sublevel Caving In Qianqiu Coal Mine

Fully mechanized mining with sublevel caving has been used in coal seam No.2 of Qianqiu Coal Mine in Yima Coal Group. According to the characteristics of super-thick conglomerate stratum existed in overlying caving 21141 face of Qianqiu Coal Mine, Thick Conglomerate fracture failure occurs when the coal face is advanced to a certain distance, it will produce more obvious stope burst, seriously affecting the mining surface safety.This thesis, uses laboratory experiments, numeric simulation and field observations and other research method, more comprehensive study of the law of overlying strata movement, Law of strata behaviors and their parameters at coal face. Firstly, physical-mechanical parameters of surrounding rock of coal seam No.2 in Qianqiu Coal Minewere tested, to classify surrounding rock of coal face, proposed the type of stope support and the main parameters for support. Secondly, similar simulation experiments was applied to study on the law of overlying strata movement, through the calculation of key strata theory to determine the main key stratum, and the overlying strata ara divided into the "three zones"at coal face. Then, based on numeric simulation, using FLAC3D to construct the numeric model, to study on the law of overlying strata movement and periodic pressure. Finally, based on field measurement of strata pressure, the roof caving to pressure law, support resistance distribution results were summarized, it shows that the pressure of stope roof clearly and has obvious phenomenon of periodic weighting.These conclusions have important guiding significance and practical value for the mine safety.