ABSTRACT
Various parameter combinations have been applied to calculate the rigid body equilibrium and stability of the primary and secondary sliding masses. The upper and medium rock strata are in a state of consequent dipping with dip angle greater than the slope gradient of landform; the lower rock strata are in a state of reversed dipping characterized by typical bedding sliding~bending. The rate of ground displacement in the direction of primary sliding plane is maximum at the top and minimum at the middle, having the property of combined traction and draught. During impoundment the sliding mass slides downwards along with the rising of water level and achieves a state of balance; after that with the new rising of water level the sliding mass slides continuously. This process is so slow that the probability for surge damage is quite small. Considering the shorter distance between the landslides and the dam, the predictions shall be further proved through practice.
