Abstract:

The stability of the primary accumulations which is called Jiuzi collapse accumulation near Wanjiakouzi hydropower station in Xuanwei City, Yunnan Province wss analyzed by using Morgenstern-Price method and strength reduction method, taking into account four conditions such as the normal water level, the dropped level, and the two levels when earthquake occurred. The stability coefficient obtained by Morgenstern-Price method decreased with the storage level not only in the normal condition but also in the case of earthquake condition. But there is little change in the stability coefficient obtained by strength reduction method when water level varied. At the same water level, smaller stability coefficient could be achieved in earthquake condition. As to simple homogeneous soil slope, similar stability coefficient and slide surface may be achieved through strength reduction method and limit equilibrium method. And greater difference may occur when the slope is inhomogeneous. Morgenstern-Price method, assuming soil in the limit equilibrium, uses slices method in forces analysis, and it can not provide the slope displacement information, and several sliding surfaces should be assigned before calculation. In strength reduction method, the limit equilibrium state can be reached by reducing the strength parameters of the materials, and not only the soil stress-strain relations can be considered, but also the slope displacement information can be obtained. However, the strength reduction method is lack of a unified standard when slope reaches to the limit failure. Both methods can provide effective analysis and evaluation for slope stability.

Key words: Morgenstern-Price method, strength reduction method, stability analysis, slope stability