Soil-Water Coupled Finite Deformation Analysis of Seismic Deformation and Failure of Embankment on Horizontal and Inclined Ground

The Noto Hanto Earthquake in 2007 caused large-scale landslide of 11 embankments in NOTO YURYO road, especially the embankment on inclined ground. In order to clarify the cause of the large-scale landslide of embankment, the laboratory tests on the embankment material, the weathering tuff and the seismic response analysis of the embankment on inclined and horizontal grounds by the static/dynamic soil-water coupled finite deformation analysis code, GEOASIA. The essential results and conclusions are follows; 1) The unconfined strength dramatically decreases by absorbing water beyond the optimum water content. 2) The landslide of the embankment on inclined ground is caused by migration of porewater during/after the earthquake. The soil element of landslide swells both elastically and plastically with structure upgradation and loss of overconsolidation after the earthquake. 3)The embankment on the horizontal ground does not slide but move a little. The soil element did not swell but consolidate after the earthquake due to the generation of the positive porewater pressure in the center of the embankment during the earthquake.