Seismic performance of single-propped retaining walls

Abstract

This thesis analyzed the dynamic performance of single-propped retaining walls in dry sand under different seismic excitations using the finite difference software FLAC v7.0 (Itasca). The structure comprises two reinforced concrete diaphragm walls connected by a row of cross-lot struts that is used to support a 9.5m deep, 18m wide excavation in dry sand. After simulating the excavation as a staged construction, a suite of thirty-two (32) different seismic inputs were applied at the base of the model. The non-linear, inelastic soil behavior was represented by the advanced PB constitutive model (generalized effective stress soil model) developed by Papadimitriou et al. (2002). In order to avoid spurious reflections of shear waves on the vertical boundaries of the finite difference model, the analyses used periodic boundary conditions. The performance of the structure was investigated by considering the wall deflections, bending moments, earth pressures and surface settlements for each of the applied ground motions. Based on the horizontal deflection of the walls, three distinct categories of performance were observed and characterized. Results of the parametric study were correlated with the characteristics of the ground motions from which wall deflections and bending moments showed clear correlations with peak ground acceleration and Arias intensity.