Abstract: The fully grouted anchor is a commonly used support method for surrounding rock in underground caverns. It is important to investigate the stress distribution along the fully grouted anchor for evaluating the stability of the combined structure of the anchor and the surrounding rock. By utilising the element embedding formulation, an equivalent method was established to simulate the anchor in the combined structure. The internal deformation of the anchor was simulated by using the axisymmetric quadrilateral element. Accordingly, the internal force and tangent stiffness of the element, the inherent internal force and algorithmic tangent stiffness of the anchor model were derived. Finally, formulations of the additional internal force and tangent stiffness of the anchor model were deduced by using the transformation between the global and local coordinates. The nonlinearity of the anchor was mainly caused by the interface failure and anchor yielding. This method can easily apply the implicit finite element formulation to perform an integrated analysis for the nonlinearity of the surrounding rock and the anchor. Therefore, this method can not only simulate the supporting effect of anchor for the surrounding rock, but also reflect the stress distribution along the anchor.

Key words: fully grouted anchor, stress distribution, element embedding, axisymmetric quadrilateral element