Numerical simulation of debris-flow initiation

This study examines debris flow records for two sites in Taiwan and simulates their initiation mechanism using numerical methods. The purpose is to establish an initiation criterion for debris flow occurrence, expressed as a critical rainfall curve. The content of this work includes laboratory tests for obtaining input parameters for the numerical model, and numerical analysis of the case histories. The analytical results show that the numerical models developed here can simulate well both consolidated undrained triaxial tests and field stress path tests. Additionally, the occurrence mechanisms of the case histories are studied. In-situ conditions such as geology, slope angle as well as hydraulic conditions are taken into consideration. Then, the developed critical rainfall curve is compared with the historical data for the two debris flow sites. This comparison shows the presented method is a good way to predict debris flow initiation.