Abstract
This study aims to establish a reasonable designing method of lugged wheels running on soft grounds such as a farm. Some theoretical analyses of soil reactions acting on a lug surface by introducing the slip-line method have been reported in the past. They did not, however, account for a movement of lug and a deformation of soils, adopting merely Rankine's slip-line field of a passive earth pressure for the case that a lug surface is nearly vertical.
Kinematically admissible slip-line fields (Table 1, Fig. 3) are proposed in this paper, classifying them according to a failure condition of soils, a friction condition of soil-lug interface, a state and a movement of lug surface. Then, a state of failure stress in slip-line fields are elusidated by analyzing angles of expansion of logarithmic spiral fields.
