Seismic Response of Anchored Steel Sheet Pile Walls in Dry and Saturated Sand

Abstract

AbstractAnchored Steel Sheet Pile (ASSP) walls are complex systems whose behaviour during an earthquake depends on the interaction between the soil, the anchor and the wall. The design of ASSP retaining walls is frequently carried out using pseudo-static methods, where the earthquake-induced inertial forces are represented using an equivalent pseudo-static coefficient that is constant in time and space, usually estimated neglecting any effects of soil-structure interaction, whereas their permanent displacements are often estimated using pseudo-dynamic approaches based on Newmark’s sliding block method. However, ASSP walls are complex systems and understanding their seismic response is necessary to determine the extent to which the design assumptions of pseudo-static methods are acceptable and the extension of Newmark’s method to the prediction of their seismic-induced permanent displacements is sound. This paper presents the results of two dynamic centrifuge tests on reduced scale models of ASSP walls in dry and saturated uniform medium dense sand performed on the Turner Beam Centrifuge at the Schofield Centre, University of Cambridge. Both trains of sinusoidal waves and realistic earthquake motions were applied to the base of the models. Digital image correlation was used to measure the displacements of a cross-section of the models during each applied earthquake. In dry sand, the largest amplification of the horizontal accelerations was observed near the retaining wall, and the main wall accumulated significant outward rotation with limited horizontal displacement of the toe. In saturated sand, the generation of excess pore pressure led to significant de-amplifications and phase lag in the accelerations, and caused larger permanent displacements of the structure.KeywordsRetaining structuresPhysical modellingLiquefactionSoil-structure interaction