Abstract: Toppling-deformation is usually found in anti-dip bedded slopes. But recent engineering investigations revealed that toppling-deformation mode could also appear in steep dip bedding slope. Analyzing the formation mechanism is of importance for the correct assessment of slope stability. In this article, the landslide III^# on the right bank of a hydropower station in the Yellow River Basin was researched by means of numerical simulation and qualitative analysis based on geological surveys. The process of landslide formation was displayed by UDEC (Universal Distinct Element Code). Results indicated that the failure process of the landslide could be divided into three stages rock mass unloading, toppling deformation, and sliding-tension fracture. The result obtained from finite element method consists with that from discrete element method, which proves that the conclusion is rational.

Key words: landslide, dip bedding slope, formation mechanism, toppling-deformation, numerical modeling