Abstract
The motion of landslide will be regulated by the internal friction angle and pore pressure during the motion of landslide. Types of pore pressure generation along the slip plane during the motion of landslide have been classified in three types. Sassa has proposed that pore pressure generation in the typical long run-out landslides such as the1984 Ontake landslide in Japan and the 1983 Sale landslide in China should be resulted from the rapid loading of landside mass onto the saturated alluvial deposits. Samples were collected from the alluvial deposits on which the mentioned-above landslides traveled, and the apparent friction angle during the rapid loading condition was measured by the high-speed ring shear apparatus. A new sled model (originally proposed by Heim) using this measured apparent friction angle could well explain the reason of low apparent friction and long travel distance of both disastrous and very mobile landslides.
