Modelling Tsunami wave impacts on the resilience of critical coastal protection infrastructure
Mohammadreza Torabbeigi, Mehryar Amir Hosseini, Soroush Abolfathi
Abstract
With the intensification of coastal hazards due to rising sea levels, increasingly frequent extreme climatic events, and reduced freeboard at coastal defenses, effective mitigation strategies for protecting coastal infrastructure are more critical than ever. Enhancing the resilience of landward critical infrastructure in tsunami-prone regions is essential for safeguarding communities and preventing catastrophic losses. This study evaluates the effectiveness of sloped dikes in mitigating tsunami-induced forces and overturning moments on coastal protection structures. A three-dimensional Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) model is developed to simulate complex tsunami wave interactions with sloped dikes. The model is rigorously validated against physical experiments, accurately capturing the hydrodynamic behavior of dam-break-generated tsunamis impacting sloped dikes. Theoretical formulations confirm the accuracy of the computed forces and moments acting on the defense structure. The study systematically examines the influence of dike geometry and crest freeboard on tsunami force attenuation across a range of Froude numbers representative of real-world conditions. Two Gaussian-based predictive equations are introduced for optimal sea dike design, offering practical insights for coastal engineering applications. Additionally, the study highlights the benefits of intermittent sea dikes, which create larger subcritical zones upstream and significantly alter downstream flow patterns. Notably, intermittent sea dikes reduce horizontal forces and overturning moments by over 30 % compared to continuous dikes, demonstrating their potential for enhancing coastal resilience.