Physical Modeling of Landward Scour Due to Tsunami Bore Overtopping Seawall

Raidan Maqtan,Saiful Bahri Hamzah,Badronnisa Yusuf,M Raza Ul Mustafa,D Bayu Endrayana,I Bin Othman,N Zulaikha Bt Yusof,M Latheef

doi:10.1051/matecconf/201820301003

Abstract

many of the post tsunami field surveys which conducted by researchers revealed that, the failure due to scour at the landward toe of the seawall due to overtopping of tsunami wave forms one of the important types of coastal defence structures failure and constitutes one of the biggest threats to their structural performance. This study was intended to investigates the scour profile induced by tsunami bores at the landward toe of the vertical seawall and to discuss the effects of the parameters; tide level, incident bore Froude number Fb, incident bore height Hb, overtopping flow Froude number Fo, and overtopping flow depth Ho on the maximum scour depth induced at the landward toe of the seawall. A set of laboratory experiments were conducted at National Hydraulic Research Institute of Malaysia (NAHRIM) with the tichnique of dam break to generate the bore like tsunami. The experiments showed that the initial water level upstream of the seawall has a significant effect on the scour profile and there is a strong negative relationship exists with Froude number of the incident bore and a strong positive relationship exists with Froude number of the overtopping flow depth above the crest of the seawall.

Highlights

Protection or mitigation processes from tsunamis disasters still an open question and considered as one of the important challenges confront the engineers and researchers
The measured flow parameters for the three flow conditions and related maximum scour depths generated at the landward toe of the seawall are summarized in Table 2 in prototype scale
The experiments were conducted to investigate the scour profile generated by tsunami bore at the landward toe of the seawall for three different cases of initial depth conditions

Summary

Introduction

Protection or mitigation processes from tsunamis disasters still an open question and considered as one of the important challenges confront the engineers and researchers. These tsunamis followed by many post disaster field studies have been conducted by researchers and revealed that, the most cause of failure of the coastal dikes and seawalls was the scour at the landward toe induced by tsunami overtopping

Results

Discussion

Conclusion