總計畫英文摘要：Due to the frequent extreme weather conditions in recent years, when the rock slopes are subject to natural triggering factors such as heavy rainfalls or earthquakes or artificial triggering factors, slope failure may occur. To prevent or reduce the damages during and after rock slope failure, one has to capture the failure mechanisms, accumulation characteristics and the deformation features of rock slope failure. From earlier researches about rock slope stability, it is well know that the rock slope failure is related to the rock slope types, and the geology conditions. However, to better plan for the evacuation routes or early warning system, it is also necessary to understand the deformation features and accumulation characteristics under different conditions. Hence, it is the purpose of this main project to integrate the information from different investigation scales, in order to facilitate the field investigation during and after the rock slope sliding disaster. Further, in addition to the fact that the rock slope failure is related to the rock slope types and the geology condition, it is also crucial to explore the effect from different triggering factors, such as heavy rainfall, earthquakes or the size of the slopes. With the deformation and accumulation features under different triggering factors, the rock slope failure mechanisms can be better characterized. It is therefore expected that proper site investigation method may be proposed to better and more efficiently understand the rock slope sliding condition, and innovative methods to analyze certain rock slope conditions are also suggested, in order to better predict the deformation and accumulation features of certain rock slopes with high failure susceptibility under given scenarios.子計畫四英文摘要：The failure of rock slopes is of crucial importance in that it can cause severe damages to the surrounding areas and the residents. From previous researches related to the rock slope sliding failure mechanisms, it is known that the failure mechanisms are related to the rock slope types and its boundary or inner conditions. In this sub-project no. 4, the main target is to explore the failure mechanisms, deformation characteristics and the accumulation features of rock slope avalanches with different sizes of slopes. The study will be carried on employing both the physical testing (featuring geotechnical centrifuge tests) and numerical simulation (featuring discrete element method). The centrifuge gravitational field can be applied to the in-house physical models to achieve similar stress levels as these in the field conditions, therefore the scale effect of the rock slopes can be discussed with the test results. In addition, the submersion condition to the slope toes is also expected to be applied as one of the boundary conditions, in order to simulate the daylight condition due to possible riverbed scouring. The discrete element models are also established for parametric study, after they are verified with the results from centrifuge testing. It is expected that the results of sub-project no. 4 can yield possible deformation and accumulation features of simplified rock slopes, hoping to shed light on characterizing the rock slope failure features in actual conditions.