Differences between LE and FE Methods used in Stability Evaluations of Soil nailed Slope

Nowadays soil nailing is used comprehensively in many construction projects, in order to prevent vertical or near-vertical excavations fall. This method has significant comparative advantages e.g. run time speed, acceptable costs as well as fast and easy adaptability with various site conditions. The Limit equilibrium method due to the simplicity and ease of use, is the most common method to determine the safety factor of slopes. Actually, the fundamental weakness of the Limit equilibrium method is not able to compute the displacements during excavating operations. Thus designers have to use numerical methods in order to analyze excavations. In this paper safety factor and sliding surface have been obtained by Limit equilibrium and finite element methods for the French national research project CLOUTERRE. The results show that safety factor and sliding surface obtained by two methods are approaching. However, Limit equilibrium method is able to predict the correct behavior of soil nail wall until the overall failure. In other words, the Limit equilibrium method can be used to check the results from the finite element method.

Keywords:

Excavation , Soil nailing , Limit equilibrium method , Finite element method , safety factor