3-D seismic stability of soil-nailed walls in plane strain and corner configurations

Soil nailing stability problems are usually studied under two-dimensional conditions. However, actual soil-nailed walls and potential failure surfaces are in fact three-dimensional (3-D). Seeing that, this work has arisen to the assessment of soil nailing stability in 3-D and two-dimensional (2-D) configurations for comparison. The inclusion of seismic forces, residual soil, and corner configurations were particular aspects of interest. First, the effect of the main soil nailing design parameters on 3-D and 2-D analysis was assessed in plane strain. Second, ground properties related to a local residual soil and the geometry of a reference soil-nailed wall were assumed for the investigation of truly challenging 3-D conditions in corner configurations. The limit equilibrium method and pseudo-static approach were adopted along with the Morgenstern–Price calculation methodology based on the global seismic stability factor of safety (FSG). The results indicated that 3-D FSG values in plane strain and convex corners were always above 2-D FSG by up to 14%. In curved concave corners, 3-D/2-D FSG differences were up to 27%, whereas in square concave corners that difference became nearly 60%. Therefore, it is recommended to perform 3-D analyses instead of 2-D in soil nailing designs, particularly when concave corners are involved.