Failure mechanism and constitutive relation for an anchorage segment of an anchor cable under pull-out loading

It is a key to reveal the failure mechanism and constitutive relation of the anchor segment of the anchor cable. By using the self-developed pull-twist coupling device, the pull-out tests for anchor cables with non-rotation and free rotation conditions were carried out, respectively, and the pull-out load-torque-displacement curves were obtained to study the failure mechanism and constitutive relation of the anchor cables. Results show that the pull-out load of the anchor cable with non-rotation is larger than that in the free rotation state, and the torque reverse force generated of the anchor cable accounts for 24.6-32.0% of the pull-out load during the pull-out tests. With the increase in pull-out load, the torque increases firstly and then decreases when it reaches the peak value. The relationships between the pull-out load and torque show the cubic polynomial and are basically linear at different stages. The failure mechanism of the anchorage segment displays the pulling failure at first and then the pulling and shearing failures. The pull-out load-torque-displacement relationship of the anchor cable goes through three stages: the loading, the softening, and the residual stages. The fitted constitutive relationship curves are in good agreement with the experimental curves. The obtained conclusions can provide a theoretical reference for the similar practice.