Large wave flume tests on wave-induced response of sandy seabed adjacent a water intake

Abstract

The response of near-field seabed under wave loads is important to the safety of subsea structures and foundations. This study investigates the wave-induced response of sandy seabed adjacent a water intake through a series of large scale model tests. The tests are conducted at currently the world's largest wave flume. The spatial and temporal distribution of dynamic sandy seabed response under regular and irregular waves is investigated. The change in excess pore water pressure and effective stress within the sandy seabed is studied through direct test measurement and combination of measurement and analytical solutions. The influences of wave height, wave period, and overlaid armor stones on the response of soil close to the water intake are analyzed. Attenuation and phase lag of oscillatory pore pressure in the seabed with respect to depth is observed in the tests, and the presence of the water intake amplifies the excess pore pressure in the upstream direction. Analysis of the effective stress shows that the principal axes of stress in the soil is subjected to continuous rotation under wave loading. Residual excess pore water pressure is generated in the tests of irregular waves with relatively large height and regular waves with relatively high frequency.