ON THE UNCERTAINTIES IN ROCK-ARMOURED BREAKWATERS STABILITY

Design of the armour of rubble mound breakwaters has historically been based on empirical equations relating armour stone movement resistance to wave-induced forces. These empirical equations are developed primarily from small-scale laboratory studies and show considerable uncertainty. While new relations have been introduced to expand ranges of application, little progress has been made in several decades to decrease equation uncertainty. There is still no consensus on the best design equation and its field of application. The design manuals, such as the Coastal Engineering Manual (USACE (2002)) and the Rock Manual (CIRIA, CUR, CETMEF (2007)), show overlap between formulas and new formulas have been introduced since these manuals were published, creating design uncertainty. A clear understanding of the relative magnitudes of epistemic and aleatory uncertainty could better focus studies to improve physics research. As a first step, the present study investigates the influence of hydrodynamic uncertainty from laboratory wave and water level measurements on the predictive models using a validated 1-D Boussinesq numerical model.