Run-out Simulation of Rainfall-induced Landslides and an Improvement of the Simulation Approach
|關鍵字:||天然壩;暴雨誘發地滑;滲流力;抗剪阻抗折減;PFC3D;案例重建;landslide dam;rainfall induced landslide;seepage force;reducing frictional coefficient reduction;PFC3D;case reconstruction|
For unfavorable geological conditions, heavy rainfall may result in large scale landslide during a torrential or typhoon season. If the run out of the landslide mass blocks a river, a barrier lake may form and create additional hazard. According to the statistics of barrier lake cases, a landslide dam has a high chance to breach in a short time; its breach may cause serious problem to the downstream of the dam. More information about the behavior of landslide dams can help to plan the strategy and management of hazard prevention. However, the real data of a breached landslide dam may not be retrievable after the prompt failure of the dams. Under the situation, reconstruction of the formation process of a previous landslide dam hence can help to provide precious information for future hazard management. The goal of this thesis is to improve the simulation approach for modeling the trigger and run-out of a rainfall-induced landslide. The particle flow code PFC3D is used to simulate the formation process of landslide dams. The improved approach in the study considers seepage forces inside the landslide mass by zoning the slide mass into several sub-regions within the mass then calculate the seepage force per unit volume in each sub-region. By zoning the landslide mass, the distribution of seepage force can be better considered. Moreover, a simple approach for reducing frictional coefficient is proposed to consider the effect of pore water pressure inside the landslide mass due the rise of the ground water table. The proposed approach does not need to rely on a trial-and-error process to identify the appropriate friction coefficient for modeling the trigger and run-out of a landslide. A parametric study of the Tai-Ma-Lee landslide dam case demonstrates that the proposed approach can reasonably trigger the landslide without the need to overly reduce the frictional coefficient. Reconstructions of other landslide cases are also presented in this thesis.
|Appears in Collections:||Thesis|