Investigation on the Reflection Coefficient for Seawalls Protected by a Rubble Mound Structure

Luigi Pratola,Maria Francesca Bruno,Matteo Gianluca Molfetta,Antonio Rinaldi,Davide Pasquali,Fabio Dentale,Michele Mossa

doi:10.3390/jmse9090937

Abstract

Sea wave reflection from coastal protection structures is one of the main issues in the coastal design process. Several empirical formulas have been proposed so far to predict reflection coefficient from rubble mound breakwaters and smooth slopes. The aim of this study is to investigate wave reflection from a rubble mound structure placed in front of a vertical concrete seawall. Several experimental tests were performed on a two-dimensional wave flume by reproducing on a rubble mound structure with a steep single primary layer armored with a novel artificial unit. A new approach for the prediction of the reflection coefficient based on dimensional analysis is also proposed, and a new empirical equation is derived. The performance of the proposed equation was compared with widespread existing formulas, and a good accuracy was found.

Highlights

IntroductionSeawalls are coastal protection structures, employed for preserving the mainland from sea waves action
The most widely used prediction formulas can be classified into two main categories: formulas based on surf similarity parameter [51,64], and relative depth [50]
This paper aims to investigate the wave reflection of a rubble mound structure used to protect a vertical concrete seawall

Summary

Introduction

Seawalls are coastal protection structures, employed for preserving the mainland from sea waves action. They are effective in stabilizing the coast from wave-induced erosion, but they are used for contrasting overtopping and consequent flooding of the inland areas with possible damage to infrastructures (i.e., roads, and buildings). These aspects are crucial within the frame of coastal risk assessment (e.g., [1,2,3,4,5])

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