Impact of Cyclones and Surge on Slope Stability of Rubble Mound Seawall

The coasts have recently been vulnerable to extreme events such as cyclone resulting in sea water inundation, overtopping in coasts and severe precipitation. Recent cyclones have left a lot of damage material-wise and causality-wise in its wake. A lot of coastal areas all around the globe have experienced water entering the houses and towns in the coastal regions and also destruction of few coastal protection measures. The precipitation accompanying has made matters worse. During cyclonic events, the storm surge increases the water level in addition to the usual tidal variations. The increase in water level, temporarily, increases the stability of the coastal slopes. However, post-cyclone the soil is saturated but the water on the seaward side returns to its normal level. This causes sudden drawdown and strength reduction. With the predicted intensification of severe cyclonic events in the future it is essential that the stability issues are addressed for a stable coastal protection structure. In this study, two common storm surge levels of western coast are studied. The stability of the slope is studied by comparing the stability of the slope pre- and post-cyclone, using a finite element package. The pore pressure variation in each location of the slope is also studied to understand the effect of the water levels on the strength of the soil.