Dynamic seabed stresses due to moving deep-sea mining vehicles

Abstract

This paper presents a mathematical model for calculating stresses due to moving deep-sea mining vehicles transferring dynamic loads to the seabed via twin or multiple caterpillar tracks. Expressions for the distribution of stresses in three dimensions are obtained for the special case of twin caterpillar tracks by using the triple Fourier transform technique, while assuming viscoelastic seabed behavior. Accordingly we establish stress attenuation functions, that allow robustly treating more complex track layouts, at no expense of accuracy. The proposed closed-form expressions can be used together with elasticity or plasticity theory methods to predict the performance of mining vehicles in different seabed conditions. We use a numerical case study to demonstrate that ignoring the dynamic nature of transferred loads may result in erroneous stress predictions, and thus vehicle performance estimates.