Centrifugal Model Tests on Anchorage Mechanism of Rockbolts Considering Tensile-Lateral Shearing Coupled Effect

Bamboo-steel composite rockbolt (BSCR) has been used in many earthen site protection projects, however, there is little study on anchorage behavior of BSCR in real stress field. Due to the large diameter of BSCR, it can bear the tensile-lateral shearing coupled effect in engineering practices of reinforcing earthen sites. The purpose of this paper is to study the anchorage mechanism, deformation characteristics and failure modes of BSCR by the means of centrifugal model tests. In this study, two kinds of rockbolts were employed to reinforce soil slopes, one is organic glass rockbolt, which is rigorously scaled from BSCR basing on Buckingham π-theorem, the other is steel wire rockbolt, which can only provide the axial reinforcing effect, they have the same axial stiffness but different bending stiffness. On that basis, the distribution and evolution laws of axial stress/strain, bending moment etc. with the change of load were compared and analyzed. The influence of anchorage layers and stiffness on the anchorage performance was also discussed. The results show that the axial stess and the bending moment increase with the increase of the load. Besides, the rockbolts with a certain bending stiffness can improve the slope stability, so the anti-bending capacity of rockbolts should be considered. Furthermore, 2 layers of organic glass rockbolts can bear bigger load, and the failure mode is progressive failure of top-down. The output from this research will provide theoretical basis for the effective and optimal use of BSCR for the conservation of earthen sites.