Measuring armour layer damage in rubble-mound breakwaters under oblique wave incidence

Abstract

This paper presents a set of scale-model tests carried out to extend the range of wave steepness values analyzed in wave run-up, overtopping and armour layer stability studies, focusing on oblique extreme wave conditions and on their effects on a gently sloping breakwater trunk armour and roundhead. A stretch of a rubble-mound breakwater (head and part of the adjoining trunk, with a slope of 1(V):2(H)) was built in a wave basin at the Leibnitz Universität Hannover to assess, under extreme wave conditions (wave steepness of 0.055) with different incident wave angles (from 40º to 90º), the structure behaviour in what concerns wave run-up, wave overtopping and damage progression of the armour layers, composed by rock and Antifer cubes. Non-intrusive methodologies were used for the assessment of armour layer damage evolution, including a laser scanning technique, stereo photogrammetry and a Kinect© motion sensor. The aim of the present work is to characterize damage evolution, based upon surveys carried out with the Kinect© motion sensor, for 4 of the 11 test series conducted during the test program.