Analytical study on load transfer mechanism of a constant resistance large deformation anchor cable

In this paper, a Macro-NPR anchor cable capable of applying high prestress and providing high constant resistance is proposed, and the load transfer mechanism is analyzed, the constant resistance is provided by the interaction between cone and sleeve. When constant resistance is generated, the outer surface of the sleeve shows an obvious expansion and negative Poisson's ratio effect. The distributions of radial stress, interfacial shear stress and axial force on the cone surface were analyzed, the radial stress is divided into five stages, including linear and constant change modes. In the stage of linear increase and decrease of radial stress, the axial force distribution increases in the form of rate increase and rate decrease, respectively. In the stage of constant radial stress, the axial force increases linearly, and the distribution of interfacial shear stress at all stages is like the trend of radial stress. The key design of Macro-NPR anchor cable is analyzed, when the anchor cable enters the constant resistance state, the cone is in the elastic stage, and most of the sleeve enter the plastic stage when the radial stress is the largest, and the ultimate radial strain of sleeve is 2.8%, which is safer. Under the load of 350 kN, the stress of the expanded area is 285 MPa, which is in a stable state. An elastic-slip model of axial force fluctuation is proposed, it is considered that the change of the axial force of the Macro-NPR anchor cable is caused by the accumulation and release of the elastic energy of the cone during the tensioning process. This research can provide theoretical basis and technical guidance for the development of similar supporting anchor cables.