Numerical simulation of the seismic response of the Zipingpu concrete face rockfill dam during the Wenchuan earthquake based on a generalized plasticity model

摘要

The strong ground motion of the 2008 Wenchuan earthquake in China caused considerable damage to the Zipingpu concrete face rockfill dam (CFRD). The maximum crest settlement was approximately 1.0 m, and compressive failure and joint dislocations were observed in the face slabs. This damage has made it necessary to understand the damage pattern and safety of high CFRDs subjected to strong earthquake shaking, and the response of the Zipingpu CFRD during the Wenchuan earthquake can be used as a benchmark for this purpose. In this study, a 3D dynamic procedure was employed to simulate the dynamic responses of the Zipingpu CFRD. The rockfill materials were described using a generalized plasticity model, while the interfaces between the face slabs and cushions were modeled using zero-thickness interface elements that follow a perfect elasto-plastic stress-strain model in the tangential direction using Coulomb's friction law. Dam deformation, face-slab stress, and face joint dislocations were simulated, and the results were compared with the field measurements. Using the generalized plastic model, the residual deformation of the dam during the earthquake could be directly obtained without being complemented by separate, semi-empirical procedures. The rockfill materials shrank to the center of the valley due to the strong shaking, causing crushing damage in the zone of the slabs. The dislocation of construction joints was also duplicated by the numerical procedure. The results of this study indicate that a 3D finite element procedure based on a generalized plasticity model can be used to evaluate the dynamic responses of CFRDs during strong earthquakes.