Breaking and Caving Mechanism Analysis for Coal Roadway Shoulder Bolting and Its Control

Aiming at the shoulder bolting rupture failure and caving problem in the process of 18126 lower crossheading excavating in Huainan Pan’er Coal Mine, through the analysis of geological conditions and the specifications of coal roadway, the roadway shoulder angle of mansard roadway under the effect of surrounding rock secondary stress appears larger stress concentration, shoulder bolting fracture mainly have the anchor end breakage, top and laneway's side interface fracture and abscission layer caused by the breaking three forms. Setting up the bolting breakage model, the fracture mechanism of shoulder bolting are analyzed, based on the study of mechanical model, according to different fracture forms, parameter optimization design was carried out. We propose a kind of standard built-in rebar with ring hole circle with wire connection lock bolt fall protection measure, with the aid of metal mesh around fixed binding, which effectively avoids the anchor end caving injuries.