Study on bottom enlarged anchoring mode and reaming parameters of bolt boreholes in mine soft rock roadway

ZHANG Weiguang; CHEN Quanjun; LIU Shaowei; WANG Peng; SHI Jiabin

doi:10.13199/j.cnki.cst.2017.12.010

Abstract：According to the deformation control problem of the surrounding rock in the mine soft rock roadway,in combination with the anchoring force calculation method of the conventional anchoring system applied to the surrounding rock of the mine roadway,the paper had a feasibility on the bottom enlarged anchoring of the borehole in the surrounding rock and provided an anchoring force calculation method of the enlarged anchoring system.The major factors affected to the anchoring force of the enlarged anchor system were the reaming shape and the stability was affected by the bearing capacity of the surrounding rock at the enlarged reaming section.The theoretical mechanics and the material mechanics method were applied to establish the simplified mechanical model of the circular table enlarged,reversed circular table enlarged and circular table enlarge.The reversed circular table enlarged optimized was provided when θ＜45°.A binary function relation curve between the surrounding rock stress σb,and the reaming parameters of the enlarged reaming section bearing area for the reversed circular table was drawn.The best enlarged anchoring length obtained was 130 mm,the best enlarged angle θ was 15°and the best reaming diameter D was 100 mm.Finally,the numerical calculation method was applied to verify the theoretical analysis results and the theoretical deduction and the simulation results were fitted.The study results replenished the disadvantage of the accurate theoretical calculation method of the bottom optimized enlarged reaming parameters for the boreholes in the mine soft rock roadway and could provide the theoretical basis.