A numerical investigation on soil thrust of single track plate for underwater mining crawler robots

Given the soft sediment characteristics of polymetallic nodule mining areas, investigating the traction performance of underwater mining crawler robots (UMCRs) during seabed traversal is of significant practical importance. The soil thrust derived from the interaction between track plates and the seabed constitutes the fundamental driving force for UMCR locomotion, making its analysis critical for equipment design and optimization. This study investigates the thrust characteristics of a single track plate using an integrated approach combining theoretical derivation, numerical simulation, and experimental verification. First, three theoretical methods are comparatively analyzed: the Soil Mechanics Method (SMM) based on the Mohr-Coulomb criterion, the Quasi-Equation Method (QEM) which accounts for resistance effects, and the Failure Surface Method (FSM) based on energy dissipation principles. Second, to address the limitations of theoretical methods in modelling large deformations, the Coupled Eulerian-Lagrangian (CEL) method is employed to establish a high-fidelity numerical model. Validated against experimental data, this simulation method proves effective in reproducing the full process of soil disturbance and failure, outperforming traditional theoretical approaches. Finally, the effects of soil shear strength and ground pressure on thrust generation and failure mechanisms are quantitatively analyzed, elucidating the variation patterns of seabed soil thrust and the evolution of failure modes under varying operating conditions.