Stability of return air roadway under repeated mining in gently inclined extra-thick coal seam
In view of the complex failure characteristics of the overlying rock after coal seam group mining,and in order to ensure the safety and stability of the return air roadway during construction and use,we use the method of combining numer-ical simulation and theoretical analysis to establish the numerical simulation of coal seam mining with different working face layouts,and to study the reasonable support range and support strength of the roadway.The research shows that:during the mining process of the working face,the stress of the overlying rock in the surrounding coal and rock mass is redistributed.When the B1 coal seam working face is mined,the affected area of the return air roadway is 80 m,and the distance increases with the northward movement of the down channel.,the vertical stress of the surrounding rock of the roadway decreases slow-ly,and the support distance of the return air main roadway decreases by 17.5％,18.75％,13.75％and 8.75％.On the ba-sis of considering the stability of the roadway and improving the recovery rate of coal resources,it's finally determined that the upper trough moves northward by 4.5m,and the research results can provide guidance for the safe excavation of the roadway.
repeated miningnumerical simulationroadway stabilityoverlying rock movement angle
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