Finite element simulation for the collapse of a dip slope during 2004 Mid Niigata Prefecture earthquake in Japan

Many landslides in mountain area occurred during 2004 Mid Niigata Prefecture Earthquake in Japan. In this paper, numerical simulations for the collapse of a dip slope by the 2-D dynamic elasto-plastic finite element method is reported. In the case, an upper mudstone has slid along the bedding plane. To simulate such a catastrophic failure, i.e., a long distance traveling failure, it is very important to consider the strain-softening characteristics of the slip surface precisely. In the analysis, the material parameters for the thin sand seam put along the bedding plane were determined by the cyclic direct shear tests of undisturbed block samples. As a result, the observed phenomena could be simulated by the analysis appropriately.