Mechanism and control technology of dynamic impact in near goaf roadway with thick coal seam

Aiming at the problems of the strong strata behaviours and intermittent dynamic impact phenomenon in Datong Minefield with hard roof and thick coal se am, taking the No. 5202 roadway in Tongxin Coal Mine as an example, combined with theoretical analysis and field measurement, the mechanism of dynamic shock in a djacent roadways was studied. Results showed that in the hard roof condition of thick coal seam, the goaf of Workface 8203 formed invert-step composite cantilever str ucture.Under the action of biaxial superimposed support pressure, the fracture of high cantilever is the basic reason of dynamic shock in adjacent roadways. Based on t his point, an effective control technology with the orientated high-pressure hydraulic fracturing of roadway roof was proposed and applied to the No.1 inferior key strata and No.2 inferior key strata.The application of technology achieved the high stress transfer into the Workface 8203.The microseismic monitoring results showed that the dynamic impact phenomenon in Roadway 5202 decreased obviously, and achieved good effects.