Variational displacement method for geosynthetically reinforced slope stability analysis: I. Local stability

This, and a companion paper ( Lemonnier et al., 1998), present a theoretical model, allowing the assessment of the safety factor of a geosynthetically reinforced slope. The present paper deals with the local stability problem, that is the determination of tension and strain distributions in the reinforcements. The global stability analysis of the reinforced slope, which includes this local stability analysis for each sheet of reinforcement, is described in the companion paper. As an improvement of the French ‘displacement method’, ( Gourc et al., 1986), the present theoretical model for the local stability analysis is based on the anchored membrane concept. Its originality is the use of the variational calculus applied to the equilibrium of the membrane. It allows the determination of the optimal shape of the membrane, which gives the minimal tension at the failure surface. This optimal shape has been found to be a log-spiral. A numerical study shows the influence of several geometrical parameters on the determination of the reinforcement tension. Finally, a case history comparison involving results obtained from six current design methods is presented and discussed.