Kinematical limit analysis for design of soil-nailed structures

Soil nailing is an in situ soil reinforcement technique that has been used during the last two decades mainly in France and Germany to retain excavations or stabilize slopes. Design of soil-nailed systems has been traditionally done using slope-stability analysis methods. These methods have been developed to incorporate the effect of the available tension and shear resistance of the passive reinforcements on the slope stability. However, they provide only a global safety factor. This paper presents a kinematical limit analysis design approach that provides a rational estimate of maximum tension and shear forces mobilized in each reinforcement. To verify the applicability of the method, the predicted forces are compared with those measured in both laboratory models and full-scale structures. The proposed design approach is also used to analyze the various failure mechanisms observed on model walls and predicted critical model heights are compared with experimental results.