On Lifting Axisymmetric Engineering Objects from a Poroelastic Seabed

Abstract The problem of an axisymmetric engineering object detachment from a poroelastic water-saturated seabed is investigated. This involves the determination of forces which are required to release a body from the seabed and the corresponding times at which this occurs. The solution of the problem involves: (1) calculation of the displacements of the seabed, performed by employing an analytical solution to the Boussinesq problem, known from the theory of elasticity; and (2) analytical description of the evolution of the gap thickness and water pressure between the object and the seabed via applying the boundary layer approximation by Foda (1982). The proposed model is used to analyse two scenarios, in which time-histories of either the pulling force magnitude or the object vertical uplift velocity are prescribed. For both scenarios, breakout times and associated breakout forces are calculated for a range of parameters defining the elastic and hydraulic properties of the seabed; the results of these calculations are presented. The limit case of a rigid porous seabed is also considered.