Movement law of overlying rock during surface fracturing in strong impact and extra thick coal seams
The movement of hard overlying strata is one of the key factors inducing rock burst.In order to reveal the disaster process and induced mechanism of impact of overlying strata movement on the working face,this paper taking the 401102 working face of Mengcun Coal Mine as the engineering background,uses theoretical analysis methods to study the spatial structure evolution characteristics of overlying strata,and implements surface L-shaped horizontal well segmented hydraulic fracturing technology for the hard roof of high overlying strata.Combined with theoretical analysis and on-site monitoring methods,the spatiotemporal evolution law of overlying rock movement in the mining area after fracturing is analyzed.The re-sults show that the hard and thick composite sandstone layer in the surface fracturing weakened area is fully weakened,and high-energy microseismic events are significantly reduced.The hard and thick composite sandstone layer in the blind area of surface fracturing forms a suspended structure,and the elastic energy is not released in advance,leading to the sudden frac-ture and movement of the rock layer when the working face is mined below,thus forming high-energy microseismic events and releasing huge microseismic energy.
rock burstextra thick coal seamoverlying rock movementsurface fracturingmicroseismic monitoring
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