Mechanical Properties and Anchoring Mechanism of Graded Lateral Expansion Bolt

In order to cope with the shortcomings of anchorage performance of traditional bolts in the field of slope, and tunnel disaster prevention, a graded lateral expansion bolt was developed, whose structural mechanical properties and anchoring mechanism are analyzed in this paper. Firstly, the constitutive relation and ultimate pullout force formula of graded lateral expansion bolt under radial load-bearing deformation are obtained based on elastic mechanics theory and physical ring model. Secondly, through the static pull test, the bearing capacity transmission law and the bearing deformation mechanism of the bolt are obtained. Finally, it is found that the bolt not only has better performance in shear resistance, torsion and energy absorption, but also has more advantages in improving the overall stability of surrounding rock and releasing the deformation energy of surrounding rock by comparing the structural characteristics of graded lateral expansion bolt and NPR bolt. The results prove that the characteristics of the graded lateral expansion bolt are more suitable for the geological environment with poor stability. This study provides ideas for the research and development of new bolts, as well as new solutions for tunnel and slope disaster prevention projects.