Influence of Grouser Geometrical Parameters of Deep-Sea Crawler Vehicle on Soft Clays

Abstract

India has been involved in developing the technology for deep-sea mining in the Central Indian Ocean Basin (CIOB) from approximately 6000 m water depth. The Central Indian Ocean Basin is abundant in nodules which are rich sources of minerals like manganese, copper, cobalt, and nickel. The mining machine has to collect the nodules from the seabed, crush them, and pump to the mother ship at the sea surface. The mining machine has to be supported on very soft sediments of shear strength less than 2 kPa. The maneuverability of mining machine becomes very critical while operating in such soft soils. One of the major challenges involved in deep-sea mining is the mobility of the mining machine on the soft seabed. Predicting the traction of the mining machine is very important for determining the mobility of the mining machine in such soft soils. To analyze the influence of geometrical parameters of the grouser on soft soil for traction performance, the conventional terramechanics approach of Mohr–Coulomb failure criteria method was used to obtain the traction parameters. The shear strength–shear displacement model of deep-sea soft sediments were obtained experimentally using a customized bevameter in bentonite soil to simulate soft soil deep-sea conditions. The traction force model for the various geometrical configurations of the grouser was numerically studied in ABAQUS software using coupled Eulerian–Lagrangian (CEL) technique. The influence of the grouser parameters, viz. shape and size, on the traction performance and the soil displacement was examined. To validate the analysis, experimental studies were undertaken with a scaled-down locomotion vehicle in simulated soft soil tank. The proposed paper brings out the studies undertaken and further analysis planned in the field.