This paper summarizes the results of an experimental study directed towards the validation of a mathematical model for the buildup of pore water pressure and resulting liquefaction of marine soils under progressive waves. Experiments were conducted under controlled conditions with silt (d50 = 0.070 mm) in a wave flume with a soil pit. Waves with wave heights in the range 7.7–18 cm with the water depth 55 cm and the wave period 1.6 s enabled us to study both the liquefaction and no-liquefaction regime pore water pressure buildup. The experimental data was used to validate the model. A numerical example is also included in the paper to demonstrate the implementation of the model for real life scenarios.
Seabed soil may undergo liquefaction under waves where the effective stresses between the individual grains vanish, and therefore the watersediment mixture acts like a liquid with catastrophic consequences. There are two kinds of seabed liquefaction: Residual liquefaction; and Momentary liquefaction. A detailed account of the topic is given in the book of Sumer and Fredsøe. The present paper is concerned with the residual liquefaction. This will result in the generation of shear stresses in the seabed soil. These shear stresses will vary periodically in time as the wave continues. These shear stresses and their associated shear deformations will gradually rearrange the soil grains at the expense of the pore volume of the soil. The latter will pressurize the pore water, and presumably lead to the buildup of pore water pressure. During this continuous progressive buildup, the pore water pressure may reach such levels that it may exceed the value of the overburden pressure in which case the soil grains will become unbound and completely free, and the soil will begin to act like a liquid, the residual liquefaction.
