Influence of anchorage length and pretension on the working resistance of rock bolt based on its tensile characteristics

Abstract In coal mining roadway support design, the working resistance of rock bolt is key factor affecting its maximum load. Effective improvement great significance to support. Based on bolt’s tensile characteristics and surrounding deformation, a mechanical model for calculating was established solved. Taking 17102 (3) face at Panji No. 3 Coal Mine China as research site, with quadrilateral section roadway, influence pretension anchorage length high-strength ordinary bolts in middle corner studied. The results show that when elastic stage, increasing can effectively improve resistance. When yield strain-strengthening stages, cannot similar. approximately 25 kN less than bolt. are considered separately, best pretensions side 41.55 104.26 kN, respectively, lengths 1.54 2.12 m, respectively. same bolt, 33.51 85.12 provide theoretical basis supporting design roadways.