Analysis of an unexpected groin failure at a low crested defence scheme

This contribution analyses the structural failure of two groins that laterally confined a coastal defence scheme placed in Igea Marina beach (IT), where six emerged barriers were converted into one single low crested structure. The site has been monitored since the works started. Recent results from bathymetric surveys, sediment samplings and geotechnical tests are presented. The storm after which the groins failed is reconstructed and modeled by means of morphological simulations with MIKE 21. On the basis of the field surveys and of the computed bed level changes during the storm, it is concluded that the groin failure can not be justified only by currents induced local scour but it was also caused by a soil resistance decrease due to partial liquefaction.