Seismic response of a pile-supported excavation on Santiago gravel

• We modeled a 26 m deep discontinuous pile-supported excavation.
• A satisfactory agreement with lateral displacement in-situ measurements was obtained.
• Lateral displacements and piles׳ internal forces predicted by 2D plane-strain are accurate enough.
• Design recommendation appears as a reasonable envelope for design purposes for moderate motions.

Non-secant anchored piling support is one of the most frequent earth-retaining systems for temporary deep excavations in Santiago, Chile. The main advantages of using non-secant piling support are their relatively low cost and ease of installation. This system is particularly efficient on stiff soils with deep groundwater table, conditions usually found in Santiago. This paper presents the results of a numerical investigation aimed to study the characteristics of earthquake-induced lateral pressures on a recent pile-supported excavation 26 m deep. The estimated static deformations of the piles were compared against some measurements performed during the excavation. The dynamic pressures, and their influence on the piles׳ internal forces, were evaluated using a synthetic Ricker wavelet in the numerical FE model. Two kinds of FE models were developed, an approximate 2D-plain strain model and a fully 3D model. The accuracy of the 2D model on predicting static and dynamic lateral pressures was also investigated.