Pressure-sinkage testing of tracked mining vehicles on fluidized sediments in deep-sea polymetallic nodule mining

The excellent grounding performance of tracked mining vehicles (TMVs) is a crucial foundation for the normal operation of the entire deep-sea polymetallic nodule mining system. Based on the weak mechanical properties of deep-sea fluidized sediments, this study conducted model tests to deeply analyze the pressure-sinkage relationship curve characteristics and the soil failure process under the vertical action of the TMV track plates. It identified the influence of soil water content on the failure mode and compaction degree and established a new segmented pressure-sinkage model, verifying its accuracy. The test results showed that the width of the track plates and the water content of the sediments had a significant impact on the pressure-sinkage relationship curve, while the sinkage speed had little effect. The bearing capacity of the sediment was an inherent property of the soil, independent of the track plate width and sinkage speed, and decreased with increasing water content. By combining the changes in soil strength and the movement characteristics of soil particles under vertical load, the pressure-sinkage model was divided into the compaction stage, elastic stage, elastoplastic stage, and plastic stage. Based on the experimental results under various conditions, a predictive model for track sinkage depth that considers sediment water content and track plate width was developed. The findings of this study can provide a scientific theoretical basis for the design optimization of parameters such as vehicle weight and track dimensions, promoting the development of deep-sea polymetallic nodule mining.