Limit Analysis of Anchor Trapdoor Embedded in Nonhomogeneous and Nonlinear Soils

Abstract

The anchor trapdoor provides a simple and economical system widely used to study the stability of similar geotechnical engineering structures, such as foundations and tunnels. In this study, the passive and active failure mechanisms were proposed to estimate the uplift capacity for anchor-trapdoor design. The nonhomogeneous soil properties were investigated with the help of the slice method, which was inspired by interpretations of integration. Within the framework of the upper-bound theorem, a nonlinear slip-line layout optimization procedure with classical tools of variational calculus was presented for a single layer to provide the basis for multilayer analysis. This approach was extended to put forward an innovative failure mechanism describing the curvilinear function for circular anchor plates in a three-dimensional space. To investigate the effects of nonhomogeneity on the stability of the anchor trapdoor, case studies were conducted for soils with linear changing cohesion and layered soils. To make safe guidance for engineers facing geotechnical limit-state problems, considering both linear and nonlinear failure modes, the stability factor calculated by a few examples was validated by lower-bound solutions and results in commercial packages.