Impact failure characteristics and support methods of roadway in largely-inclined broken coal seams

Rockbursts in roadways of largely-inclined coal seams are asymmetric, and the support method is accordingly special. With Gushan Coalmine as engineering background, the principle of bolt solid falling off and asymmetric failure of roadway surrounding rock was revealed, the combined asymmetric support method of full section anchor cable, mesh and shotcrete was puts forward, and field tests were carries out. The results have shown that with the development of plastic zone of surrounding rocks and weathering of exposed broken coal, the axial force of bolts decreases seriously, the anchor body is approximately in zero pressure zone, and falls off as a whole under the impact load; there is large vertical stress in two sides of the roadway, and high horizontal stress in the roof and floor; with the participation of coal seam dip angle, the roadway structure appears to be roughly perpendicular to the coal seam. Based on the principle of roadway failure, the side anchor cable is proposed to replace the side anchor, and the anti-weathering shotcreting of anchor mesh coal body is carried out to solve the problem that the axial force of anchor decreases and the anchor solid falls off as a whole to control severe symmetrical failure of shoulder and bottom corner surrounding rock. Engineering tests show that the method not only improves the ability of surrounding rock to resist rock burst, but also greatly reduces the deformation of surrounding rock. © 2021, Editorial Board of Journal of Mining & Safety Engineering. All right reserved.