Prediction of external wave pressures on a rubble mound breakwater

The external pressures on the front face of a rubble mound breakwater resulting from wave attack are examined in this paper. This is done through extensive model tests employing regular waves up to 30 cm in height, on a conventionally designed breakwater with front slopes of 1:1.5, 1:2, and 1:3. The measured pressures are examined based on their relationship to a number of different parameters, including wave steepness, wave height, wave period, breakwater front slope, core permeability, and elevation on the breakwater relative to the still water level. The average differential pressure, the maximum recorded differential pressure, the average minimum pressure, and the pressure rise and fall times are investigated, producing a regression equation for each case based on a number of independent variables. The regression equations demonstrate the great effect of the elevation on the breakwater, and often wave steepness; the much lesser effect attributed to the breakwater front slope; and the minimal effect that the core permeability has on most of the components describing the external pressures measured on a breakwater under wave attack. Key words: breakwater, rubble, pressure, external, prediction.