Mechanical properties and soil failure process of interface between grouser of tracked mining vehicle and deep-sea sediment

Tracked mining vehicles (TMVs) are key equipment in deep-sea mining systems and can easily slip when walking on soft sediments on the seabed. Thus, it is important to investigate the effect of track parameters and grounding-specific pressure on the shear interaction between mining vehicles and sediment. The sediment was simulated using a mixture of bentonite and water, and a shear test of the track with a single grouser and sediment was conducted. A numerical model of the track–sediment shear test was established, and the shear strength and failure mode of the sediment soil under the track action were examined. The results demonstrate that the peak shear strength of the track–sediment interface increases with an increase in the grounding-specific pressure, gradually increases with an increase in grouser height, and tends to stabilize at a given level of grouser height. Owing to the presence of the grouser, the deep-sea sediment transitions from the elastic state to the plastic state faster than the typical clay during the shear test. The variation law of peak shear strength at the track-sediment interface with the height of track grouser under different grounding-specific pressures was analyzed, and a modified shear stress-displacement relationship model was proposed. Wedge failure is the predominant method of failure for a single-grouser shear sediment soil at various heights. The primary factor affecting the horizontal disturbance range is the grouser height, and the range increases as the grouser height increases; the primary element affecting the vertical disturbance range is the grounding-specific pressure, and the range increases as the grounding-specific pressure increases. The relationship of the grouser height and cohesiveness with the interfacial shear strength was examined and a new shear stress–displacement relationship model that can accurately capture the shear mechanical behavior between the track and sediment under various grouser heights was proposed. In conclusion, the study findings could serve as a guide for the engineering design of a TMV walking system.