Multi-stage Rotation-Stirring and Diameter-Expanding Integrated Strengthened Anchoring Technology for Large-Diameter Cable Bolts and Its Applications
摘要
Large-diameter cable bolts have been widely applied in roadway surrounding rock control for their high-strength support. However, under conditions of soft surrounding rock, the anchoring efficiency of resin is compromised by poor mixing and low compactness. Furthermore, the large diameter of cable bolts leads to a narrow gap between the borehole and cable bolt, preventing the use of anchoring enhancement structures designed for traditional small-diameter cable bolts. Therefore, the full support potential of large-diameter bolts is often underutilized. To address these issues, a multi-stage rotation-stirring and diameter-expanding integrated strengthened anchoring technology suitable for large-diameter cable bolts was proposed. A multi-stage bag-breaking rotation-stirring component and a reaming and guiding device were developed. Through a comprehensive research approach combining laboratory and field tests, the proposed technology’s effectiveness in enhancing the mixing reaction efficiency and density of anchoring resin, and in improving the anchoring force of large-diameter cable bolts was confirmed. Moreover, an anchoring force calculation method is proposed based on factors influencing the anchoring strength. With strengthened anchoring, the proportion of insufficiently reacted sections decreased by 68%, while that of high-density sections (without obvious gaps) increased by 42%. From a microscopic perspective, the cured resin exhibits uniform curing shrinkage and sufficient reaction, with tightly cemented resin particles. The average porosity decreased by approximately 5.3%, and the average distributed pore size decreased by approximately 2.3 μm. The results obtained by laboratory and on-site anchoring force tests indicate that the cable bolt anchoring force increased by over 30%. Observations from industrial applications indicate that the surrounding rock deformation was reduced and the cable bolt failure rate decreased by 21.75%. Moreover, the key structural layout of this cable bolt anchoring enhancement device facilitates industrial production. The design does not affect cable bolt construction and effectively harnesses the support of large-diameter cable bolts, ensuring stable and reliable anchorage in soft-rock environments.