Seismic Analysis of the Zipingpu Concrete-Faced Rockfill Dam Response to the 2008 Wenchuan, China, Earthquake

This paper presents the findings from both the detailed site investigations and the computational analyses on the Zipingpu concrete-faced rockfill dam (CFRD), a 156-m high dam in which 100-cm permanent settlement and 60-cm horizontal displacement occurred during the 2008 Wenchuan, China, earthquake. The Zipingpu CFRD was 17 km away from the epicenter and was considerably damaged by the Wenchuan earthquake. It was estimated that the peak acceleration in the top of the dam along the axial and vertical direction was about $20.0\mathrm{m}/{\mathrm{s}}^2$, and the peak acceleration at the river level was about $16.0\mathrm{m}/{\mathrm{s}}^2$. It was calculated that peak acceleration of dam bedrock was more than $5.0\mathrm{m}/{\mathrm{s}}^2$, and the intensity (Chinese scale) was more than IX. Based on an in-situ investigation, the peak value of settlement of the dam crest reached 744.3 mm, and the peak value of horizontal displacement toward the right and left abutment are 226.1 mm and 106.8 mm, respectively. The actual experience of the peak acceleration and seismic intensity of the Zipingpu CFRD in this earthquake was considerably beyond criteria used for the original design standards. To simulate the seismic activity and damage, a three-dimensional (3D) numerical model of the Zipingpu CFRD is established and the numerical simulation analysis of Wenchuan earthquake damage is presented. The calculated results show that the numerical analyses are consistent with the in-situ investigation. The seismic performance of the Zipingpu CFRD during the Wenchuan earthquake is reproduced in the numerical model. The acceleration response, permanent deformation, and damage characteristics of the Zipingpu CFRD in the Wenchuan earthquake are understood as a result of this study. It should also be highlighted that the valuable and rare data from the seismic response of such a large dam will be useful for further case studies.