Estimating tsunami-induced uplift pressure

Tsunamis can cause sediment instability, which in turn, can lead to significant damage to coastal infrastructure and buildings. Accordingly, engineers need guidance to retrofit or design coastal infrastructure and buildings in tsunami-prone regions. Starting with a coupled seepage−deformation model, the authors specify assumptions, an initial condition and a boundary condition to produce a closed-form solution for estimating excess pore-water pressure head gradient as a function of depth, h′_e(z). The estimated values of h′_e(z) can be used to predict the susceptible scouring zone and uplift pressure during tsunami drawdown. The results show that, for a reasonable coastal sand bed, the simple closed-form solution matches well with the results from a coupled seepage−deformation model for hypothetical and field-measured tsunami loading. The closed-form solution is used to create a method for predicting the tsunami-induced uplift pressure. The preceding methodology is developed to be compatible with code-based guidance.