Limit load of strip anchors in uniform cohesive-frictional soil

The conventional approaches for determination of pullout capacity factors of anchor foundation are restricted for only cohesionless or cohesive soils. These approaches are incompetent for the estimation of the anchor capacity in soils that have both cohesion and frictional resistance - a common scenario of native soils. In this study, a rigorous nonlinear Finite Element (FE) analysis is carried out to evaluate the pullout capacity factors Nc, Nq and Nγ of strip anchor based on the contribution of cohesion (c), surcharge (q), and self-weight (γ) of soil. Before conducting detail parametric studies, the numerical outcomes of current finite element studies are validated with the existing experimental and numerical results. Numerical results reveal that Nc changes from nonlinear to linear fashion with the increase of friction angle for altering anchor orientation from horizontal to vertical, while a reversible nature is found for Nq and Nγ. The results of these analyses are provided as design equations for the convenience of design engineers as a function of anchor embedment depth (H/B), friction angle (φ), and the inclination angle (β). Finally, a roughness modification factor Nc, Nq and Nγ for the vertical anchor is proposed.