3:30 PM - 4:45 PM
[HDS05-P09] Simulation of the Aratozawa Landslide using Ring Shear Tests and LS-RAPID model
Keywords:Aratozawa landslide, Ring shear tests, Shear strength reduction, LS-RAPID
The laboratory experiment for the Aratozawa samples was carried out by means of ring shear apparatus ICL-2 version. This version is the newest apparatus that has been built so far by Sassa and other colleagues started in 2012 for practical use. Still, the main purposes of this apparatus for landslides are to observe the pore water pressure generation in undrained condition, shear strength reduction and failure motion behavior of samples within a large shear displacement. The development of this ring shear apparatus also emphasizing the change of normal stress platform from pillar-beam based, to the single central axis-based. Several parameters resulted from experiment by ring shear tests then occupied for the LS-RAPID geotechnical simulation. Landslide simulation model using LS-RAPID aims to observe the overall process of landslide phenomena started from the initiation process by pore pressure increase and seismic loading up to the moving process which involving the volume enlargement and traveling process of the landslide mass.
The critical pore pressure ratio was obtained from ring shear tests. In addition, the friction coefficient, shear displacement at the start of shear strength reduction and steady state shear resistance of the Aratozawa samples were also produced from the tests. We brought the results from ring shear tests as an input parameter in the LS-RAPID. The results of LS-RAPID so far could explain the initiation mechanism and motion of Aratozawa landslide. However, further detailed study is still needed, particularly for the factors from reservoir catchment and relation of reservoir and groundwater condition before and when the earthquake takes place.