An improved calculation model for the wave-induced pore pressure distribution in a rubble-mound breakwater core

Abstract

The spatial distribution of the wave-induced pore pressure height in the core of a conventional rubble-mound breakwater is studied in this work. Use is made of existing theoretical and experimental knowledge to establish a calculation model for the pressure distribution on the front core slope and the attenuation of pore pressures within the breakwater core. The new model formulae are derived empirically and calibrated by means of a non-linear regression analysis of pore pressure measurements in a large-scale conventional breakwater model, under non-overtopping and non-breaking wave conditions. They relate the spatial distribution of pore pressure height to the sea state in front of the breakwater considering a homogeneous breakwater core, but do not contain any material properties related to the porous flow resistance. The new calculation model predicts the pore pressure distribution with higher accuracy than the existing method generally employed and is applicable in a broad range of wave conditions. The calculation model is validated with additional experimental data from pore pressure measurements on a small-scale model, confirming the capability of predicting the pore pressure height under varying wave conditions. The comparison between both models moreover provides insight into the general applicability of the calculation model.