ABSTRACT
Because of increasing abnormal climate, it is reported that a large number of slope failures are caused by heavy rain and lose valuable lives and fortune (for example, Wang and Shibata 2007). Model test may be a useful tool for studying and understanding mechanism of the slope stability during heavy rain. However, such a model test is not only costly, but also requires a lot of time to perform the test, due to its large scale. The centrifuge model test may be a powerful testing method, in which the large centrifugal acceleration is applied to the model ground so that the stress conditions are the same as those in the prototype in spite of the small scale (Soga et al. 2003). The objective of this research is to study the behavior of unsaturated ground during heavy rain by the centrifuge model test. It is considered that a slope failure may be caused by movement of water in unsaturated ground. Therefore, special attention was paid to measure pore water pressures (PWP) in the model ground by placing several pore water pressure gauges. Two types of grounds were prepared: flat and slope grounds consisting of two soil layers with different permeability.
