Field Tests on Anchoring Mechanism of the Bamboo-Steel Cable Composite Anchor with Single Reinforcement

Under the influence of natural condition and human activities, the majority of earthen sites are suffering from the damage with different degrees, which are in urgent needs of rescuing and conservation. The previous conservation experiments and practices show that the conservation methods for the main body of earthen sites should adopt the traditional craft as far as possible to achieve the goal of "maximum compatibility, minimum intervention". A type of the bamboo-cable composite bolt (a 7 @ 5 steel strands within the bamboo, with the length of 5 m) is chosen to carry out the field experiment of anchoring mechanism of composite bolts. The results indicate that: the main destruction way of composite anchor is that the composite material interface slips out of softening; the composite anchor axial stress distribution is exponential distribution with the pullout load increases; when pull-out load is smaller, interfacial shear stress shows the exponential function distribution, decreasing from the start to the end of the bolt, and the peak shear stress deviates to the end with the load increases; Steel strand axial stress is higher than the bamboo pipe axial stress; Composite bolt shows the material memory characteristics in the process of cycle pullout; The strain value of bamboo internal surface is higher than that of the outside surface in the same section; The limited pullout force is 238 KN in the bolt with the plats in end, whereas, it is 204 KN for the bolt without the anchor plates.