Geosynthetic reinforced rubble mound breakwater for mitigation of tsunami-induced damage

Abstract

Several rubble mound breakwaters (RMB) were damaged and even collapsed during the past tsunamis. The main reasons for the failure of the breakwaters occurred due to the combined effects of seepage and scouring. Limited articles are available dealing with the behaviour of RMB during the tsunami. Furthermore, few available articles are related to developing countermeasures for the RMB against tsunamis. Therefore, an attempt has been made in the study to determine the exact behaviour of the RMB under the action of the tsunami. In addition, the main aim of the present study is to develop countermeasures to make the breakwater tsunami resilient. The present study proposes a novel geosynthetics-reinforced RMB to mitigate tsunami-induced breakwater damage. Based on the available information, this is the first time geosynthetics have been used in the RMB to mitigate tsunami-induced damage. Geogrid layers, geobags, sheet piles and crown walls (with shear keys) are adopted as countermeasure elements against the tsunami. Since the height of a tsunami can exceed its design tsunami height, tsunami waves were allowed to overflow the breakwater in physical model tests. Comparative analyses between the reinforced and unreinforced RMB were performed by conducting physical model tests, analytical tools, and numerical simulations. © 2023 Elsevier Ltd