Abstract: Soil anchoring techniques have been widely used in geotechnical engineering. The present research status of soil anchor solid interface element form is briefly described, and the characteristics of the soil anchoring interface layer are analyzed. Then a new composite interface element is proposed, which consists of a contact element and a solid element. Wherein the contact element is considered as the sliding friction element between the anchor element and soil, and the solid element reflects swelling characteristics of surrounding soil body when rock bolt is drawn. The new composite element of the interface layer between the anchor and soil is implemented into ANSYS software. The failure characteristics of the interface layer are simulated and analyzed when rock bolt is drawn. The shear stress distribution process of the interface layer is obtained with the increase of loading. The destruction of the interface layer is divided into three stages, namely the linear stage, slippage expansion stage and slippage stage. The load-displacement curve of soil anchor pull-out is obtained by in-situ soil anchor drawing tests. Finally, the characteristics of the curve are analyzed and numerical results are verified as well.

Key words: soil anchoring, contact interface, interface element, constitutive relation, numerical simulation, drawing test