An experimental investigation is conducted for comparative study on traction performance of grouser shapes on an extremely soft seabed. Two kinds of grouser shapes are investigated with 18 grouser models consisting of 9 triangular types and 9 blade types. The grouser span is kept constant. Cohesive soil of seabed is modeled by means of benthonite-water mixture. Sinkage and traction forces are evaluated for each grouser model with respect to changes of relative bearing pressure to the residual shear strength of soil and shearing velocity.
Tracked vehicles are typically used for off-road purposes such as construction machinery, agricultural machinery, military-purposed vehicles, amphibious vehicles, snowmobiles and transportation in swamp area. For undersea works, tracked vehicles find applications to underwater cable and pipe burying systems, dredges, trenchers and support of researches (Turnage et a1. 1979, Ivanov and Karev, 1990). Nuttal (1971) examined the applicability of existing estimation methods for maximum net traction of tracked vehicles ashore to the tracked vehicles crawling on the seaf1oor. A tracked vehicle was used for in situ measurement of subsea soil mechanics and trafficability (Anderson et al. 1972, Gibson and Anderson 1974). Herrmann (1978) suggests a lightweight tracked vehicle or Archimedean screw for a deep ocean running gear module. Muro (1983, 1989) studied on the trafficability of tracked vehicle on very soft bottom and investigated grouser effect on tractive performance of a bulldozer running on soft marine sediment. Tracked vehicle has been also investigated as a running gear of deepseabed miner for manganese nodules in 5,000m deep ocean. Bode (1991) examined the performance of tracked vehicle on soft cohesive soil through experiments of track segment model and suggested a method for steady state simulation. Bode's method was extended by Zhang (1995) for a turning simulation method of tracked vehicles.