STUDY ON THE FORCE TRANSFER PROCESS OF THE ANCHORAGE INTERFACE OF BAMBOO BOLT IN THE RAMMED EARTH SITES

Bamboo and wood anchoring technique has been widely used in the reinforcement of rammed earth sites in recent years. However, its force transfer mechanism at the anchorage interface is still unclear, which seriously restricts the large-scale application of anchorage technology in scientific way. Relevant research results have confirmed the importance of a reasonable bond-slip model for predicting the performance of the anchorage system. Based on this, the bamboo-modified slurry-rammed earth anchoring system is taken as an example to study the whole process of force transfer in anchorage interface based on tri-linear bond-slip model considering complete debonding phenomenon. Firstly, the force transfer process of the anchorage interface was divided into six successive stages, and the corresponding interface stress, strain distribution and evolution process are analyzed theoretically, the closed form solutions of bolt axial deformation, anchorage interface slip, shear stress and shear strain were also derived. Meanwhile, the calculation method of ultimate anchorage force and effective anchorage length has been proposed. On this basis, the feature points parameters of bond-slip model were calibrated by identifying the different stages of load-displacement curve. Finally, the rationality of the analytical model was validated against two in-situ pull-out tests in rammed earth sites. The influence of anchorage length and axial stiffness of anchor bolt on the anchoring performance was emphatically analyzed in the text. The analytical model proposed by this paper has wide applicability to the analysis of the force transfer process of anchorage interface with complete debonding phenomenon, and can provide reference and guidance for the design of anchoring engineering of rammed earth sites.