Discrete element simulation of track-plate shearing behavior in two types of deep-sea sediments

Deep-sea sediment microstructure governs track–sediment interaction, while its sediment-specific effects remain insufficiently differentiated in existing track-scale DEM studies. This study develops material-specific DEM models for Western Pacific calcareous sediment (WP-S) and Clarion–Clipperton Zone siliceous sediment (CCZ-S) by integrating shear-plane SEM observations and vane-rheometry calibration. A parallel bond model represents the cemented aggregates of WP-S, whereas an adhesive rolling resistance model represents the weakly attractive flocculated fabric of CCZ-S. The calibrated models reproduced Bingham-type WP-S and shear-thinning CCZ-S responses. Track shearing simulations of single and serially arranged track plates evaluated the effects of sediment type, plate number, and shearing velocity. Both sediments exhibited wedge-shaped failure, with broad bond-controlled disturbance in WP-S and localized compaction and rearrangement in CCZ-S. At 60 mm/s, the final thrusts of the double- and triple-plate systems were 33.9% and 47.3% below the linear estimates for WP-S, and 25.3% and 37.8% below those for CCZ-S. Increasing the shearing velocity from 40 to 80 mm/s raised the final three-plate thrust by 48.8% in WP-S and 73.7% in CCZ-S, although multi-plate efficiency did not increase monotonically. These results show that sediment microstructure and repeated disturbance govern thrust redistribution, supporting more realistic traction prediction for seabed mining vehicles.