Analysis on mechanism and effect of rock bolts and cables in gateroad with coal seam as roof

Taking a tailgate with coal seam as roof in Tashan Coal Mine in Datong mining district for example,the numerical simulation of stress and deformation characteristics in the rock surrounding the tailgate was studied,with different thickness of roof coal,different tailgate locations,different height-width ratios,different in-situ stress and different pretension of bolts and cables through finite difference numerical software FLAC3D.The results show that as the thickness of roof coal increases,the stress concentration area enlarges while the stress decreases within the roof coal of less than 10 meters;the distribution of stress concentration area in the coal pillars caused by the tailgate driving and adjacent longwall face mining is in the shape of "triangle";with the same tailgate height,as the tailgate width increases,the stress concentration in the roof coal increases while the stress in the floor decreases;the higher the strength of coal and rock is,the higher the surrounding rock stress is;the bolt and cable pretension should form an effective compression stress zone which is supposed to overlap in anchorage range in surrounding rocks.The underground tests showed that the high strength and high pretension bolt and cable can effectively control the deformation of the surrounding rocks,provide an effective approach to support the gateroads with coal seam as roof.