A block failure model for deep-sea sediment between grousers of deep-sea mining vehicles based on elasto-plastic theory

Avoiding in-situ skidding of tracked deep-sea mining vehicles on soft sediment and reducing disturbance to soft sediments are the basic requirements for ensuring the regular operation of seabed mining. The in-situ skidding problem of the tracked deep-sea mining vehicle can be explained by the block shear failure phenomenon of deepsea soft sediment. We analyzed the force state and elastic-plastic state of soft sediment disrupted by a crawling grouser and established the block failure model. The elastic-plastic failure range calculations obtained in the model is used to select the spacing between adjacent grousers to maximize the thrust provided by the grouser. Due to the irreversibility of plastic failure, the range of plastic zone failure is used to measure the extent of the sediment disturbance by the grouser. By analyzing the influence of multiple parameters on the failure range of the plastic zone, we provide direction for finding ways to reduce sediment disturbance. It is found that among these parameters, the grouser's width and height, which represent the shape parameters of the grouser, have the most critical effect on the plastic failure range of the sediment. But when the width exceeds 0.3 m, and the height exceeds 0.2 m, the benefit of reducing the failure range by increasing the grouser's width and height will be