An experimental method to verify the failure of coastal structures by wave induced liquefaction of clayey soils

Abstract

Although the dynamics involved in the liquefaction process are understood reasonably well, experimental work to reproduce the sinking of structures due to liquefaction, which is representative and repeatable, has so far not been recorded. In this work, three sets of experiments were performed in an attempt to fill the gaps in the knowledge by modelling a small scale reproduction of the failure. Firstly, an analysis of the role of the proportions of the initial fine sediment and water content is presented; secondly, a group of tests involving a vertical breakwater were performed, and thirdly, an experiment was carried out to reproduce the failure of a submerged structure on a clayey bed in the presence of waves. From these experiments, we were able to set thresholds for bed composition, below which soil liquefaction is likely to occur. It was determined that the potential to liquefy increases with the initial water content and that soils of 40% or more clay content may liquefy. This methodology has proven to be repeatable, allowing the reproduction of the sinking of coastal structures due to liquefaction of the underlying soil.