Time and again earthquake-induced damage occurs worldwide as a result of soil liquefaction, especially in loose sands with high groundwater levels. One of the most common types of damage caused by liquefaction results from vertical soil deformations, in other words settlements. This article contributes to the determination of earthquake-related settlements in dry and saturated sands using two-dimensional finite element analyses (2D-FEA) and semi-empirical methods. The comparison of the results obtained from both methods showed that the 2D-FEA give relatively low settlement values compared to the values obtained from the semi-empirical methods. This is mainly explained by the relatively large horizontal earthquake accelerations resulting from the one-dimensional, equivalent-linear dynamic analyses and by the accumulation of earthquake waves at the upper edges of the numerical models.

Liquefaction is a dangerous and temporary phenomenon whereby water-saturated soil loses all or part of its strength. Undrained conditions associated with cyclic loading increase water pressure in soil pores, thereby reducing effective stress. The aim of this study is, on the one hand, to report on the phenomenon of liquefaction of sand, clay and silt deposits in more or less water-saturated zones in the located at the heart of the central alluvial plain of the Oued Sebou in the mio-plioquaternary Gharb basin and, on the other hand, to study the ability of semi-empirical methods to correctly assess liquefaction potential, while specifying the most appropriate method for the area studied. The study is based on data from experimental results of static penetrometer tests between the Mnasra - Ouelad Salama zone in the Oued Sebou alluvial plain of Morocco's mio-plio-quaternary Gharb basin, made up of sandy, sandy-clay, sandy-silt and silty-sandy formations, which are more sensitive to liquefaction due to their saturation and grain size. We present and discuss the results of Olsen's method, Juang's method and Robertson's method, which are based on the CPT static penetrometer test, as well as looking at the impact of dynamic loading and soil structure on liquefaction probability index values.