Anchoring Performances Analysis of Tension-torsion Grouted Anchor Under Free and Non-free Rotating Conditions

For the failure mechanism of the anchor cable lags behind the practice demand for theoretical models, Abaqus technique was used to analyze the anchoring performances of the grouted anchor under the conditions of free and non-free rotating. The tension-torsion coupling characteristics and the progressive failure mechanism of the anchorage segment were studied during the pull-out test. The torsion response of the anchorage segment and the internal horizontal and vertical strain changes in the anchoring concrete were also analyzed. Results show that the proposed calculation model of the anchor cable is verified. With the increase of the pulling-out displacement, the load response of the anchored section is gradually transferred from the inside to the outside. The anchoring stress in the concrete undergoes the evolution process of rod shape-bell shape-aquarium shape-spear shape. As an intermediate transition layer, the anchoring agent breaks before the concrete and at the same time that plays a buffering effect. Under the action of tension-torsion coupling, the anchoring agent is prone to tensile-shear composite failure. There are two different ways of transmitting force for the grouted anchor under rotating and non-rotating conditions, and the anchoring force of the anchor cable will be reduced in the state of free rotation. The obtained conclusions can provide a reference for the similar anchoring practice. Keywords: Grouted anchor, Tension-torsion coupling, Numerical simulation, Failure mechanism, Anchoring force