Seepage Analysis of Resilient Rubble Mound Breakwater Under Tsunami Overflow: Numerical Analysis

Abstract

A breakwater is an offshore structure which is constructed to protect ports and harbours from the destructive effects of sea waves, currents, typhoons, and even tsunamis by reflecting and dissipating their wave energies. Among the various types of breakwaters, the rubble mound (RM) breakwater is the most common type constructed near the seacoasts of many countries across the globe. The most devastating natural hazard that a breakwater could possibly encounter during its design life is a tsunami wave. Several breakwaters were severely damaged or completely collapsed in several countries during past tsunamis. The coastal areas of India bore the brunt of the damage during the 2004 Indian Ocean tsunami. Therefore, it is utmost important to develop new techniques such as placing special gabions and rows of sheet piles as countermeasures for making RM breakwaters tsunami resilient. One of the longest breakwaters in India, the north breakwater at the Ennore Port (Chennai) has been chosen as prototype. The numerical modelling of the RM breakwater along with the seabed soil with two layers has been done in Plaxis 2D to observe the effectiveness of these countermeasures during tsunami-induced seepage through the breakwater and seabed soils. It was found that the provision of special gabions with impermeable layer and sheet piles beneath the mound can effectively prevent the seepage of water that occurs during tsunami overflow. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.