Abstract
The objective of this research was to clarify the three-dimensional deformation structure of the moving body of landslides. The analysis was based on landslides in the Tohoku district and existing observation data, and revealed that deformation of the moving body has two types. In one type, the displacement of the slip surface is almost equal to the displacement of the ground surface. In the other type, the rate of displacement is fast in the central parts, slow at the ends of the horizontal sides, and along the vertical sides it increases gradually from the slip surface towards the ground surface. Furthermore, the displacement was found to be like a viscous flow similar to debris flows or plastic deformation seen in glaciers. These types of deformation depended on the position within the landslide body as well as constituent materials. It is therefore presumed that such types of deformation are related to the extent of fracturing or weathering of moving body components. The results of this study will be useful for designing restraint works based on analyses of the three-dimensional stability and deformation of landslide slopes.
