Influence of Soil and Pore Water Parameters on the Process of Lifting an Axisymmetric Object from a Sandy Seabed Surface

Abstract The removal of subsea objects from the seabed is a crucial challenge for the offshore industry, necessitating the accurate prediction of pull-out resistance from an engineering perspective. To address this problem, a parametric analysis was undertaken to investigate how seabed properties influence the extrication force and the critical extrication time required to detach an axisymmetric object from a sandy sea bottom. The ranges for selected seabed parameters, including soil shear modulus, Poisson’s ratio, permeability coefficient, porosity, bulk modulus of pore water, and water viscosity, were established based on data from the existing soil and fluid mechanics literature. The results indicate that achieving robust and reliable estimates of the maximum extrication force and the critical extrication time in practical scenarios, such as underwater engineering and marine salvage, requires direct laboratory determination of the bulk modulus of water and the permeability coefficient and porosity, through tests on in-situ seabed and water samples. In contrast, appropriate values of the shear modulus, Poisson’s ratio, and water viscosity can be sourced from the existing literature, provided that the type and condition of the seabed soil are accurately characterised.