Abstract: At present, the viscoelastic method is widely used in the dynamic analysis of concrete faced rockfill dams (CFRDs), basically forming a method framework: the viscoelastic model for calculating the dynamic response and the permanent deformation model for calculating the permanent deformation. Then the dam safety is evaluated through both the dam dynamic response and the permanent deformation. However, when the current method is used in the dynamic analysis of the CFRDs, there is an obvious defect, i.e., it cannot consider the influence of permanent deformation on the stress of the concrete slab during the strong earthquakes, which may cause serious errors when applying the method in CFRDs with obvious permanent deformation. Therefore, it is necessary to improve the current method. This paper suggests to adopt the strategy of “divide first and combine later”. Firstly, the dynamic displacement and permanent displacement of the dam are calculated separately, then the two are added as the actual displacement of the structure, and finally, the strain and stress of the structure are calculated based on this actual displacement. This paper took the Yulong Kashi CFRD as an example to illustrate the necessity of the improvement.

Key words: CFRD, earthquake analysis, viscoelastic method, finite element method, Yulong Kashi