An approach for predicting earthquake-induced permanent displacements of embedded cantilever walls in soils with cohesion

Prediction of the earthquake-induced permanent displacements of retaining structures is a key step in the context of a performance-based design approach. For retaining walls with shallow foundations, this issue is usually dealt with using the well-known Newmark sliding block method. However, several studies have shown that this method is unsuitable to provide a trustworthy prediction of the permanent displacements undergone by the embedded cantilever retaining walls under seismic loading. To overcome this drawback, a new method of practical interest is proposed in the present study for a prediction of the earthquake-induced permanent displacement of these structures. In such a method, the wall movements are evaluated solving a simple equation of motion whenever the ground acceleration exceeds a critical value. This latter value is updated during the seismic event by calculating the forces acting on the wall by means of a closed form solution recently derived by the authors. The method is simple to use and requires few conventional parameters as input data. These features make it suitable for current applications. To assess the predictive capability of the present method, comparisons with the results of a centrifuge test documented in the literature and with those of a large number of ideal case studies solved using a finite element code, are presented. The effectiveness of some measures to reduce the wall displacements is also discussed.