Study of seismic response of colluvium accumulation slope by particle flow code

Colluvium accumulation slopes (CAS) are widely distributed in Sichuan Province of China, especially in the regions with intense earthquake histories. These kinds of accumulations show obvious discontinuous and heterogeneous characteristics, to which the discrete element method (DEM) for discontinuous material is more suitably applied. Wenchuan earthquake with a magnitude of 8.0, caused a large number of debris flows or landslides in the colluvium formations, which are densely distributed in the quake-hit region in Sichuan province. The dynamic response of CAS is a key problem for study of stability of these kinds of slope. In this paper, PFC (Particle Flow Code) from Itasca based on DEM is used for modeling the dynamic response of the colluvium accumulations and some typical models were built according to the geological investigations carried out in the epicentral area. Horizontal shearing waveforms of WenChuan earthquake were input into the model for the study of the dynamic response of overlying colluvium accumulation and bedrock. The modeling results of different models under the same seismic conditions are described and analyzed at the end of the paper.