Lessons from Damages to High Embankment Dams in the May 12, 2008 Wenchuan Earthquake

Five embankment dams with the height over 100m experienced the May 12, 2008 Wenchuan earthquake with a magnitude of Ms 8.0. Damages to the Bikou loam-core-wall earth-rockfill dam and especially to the Zipingpu concrete face rockfill dam (CFRD) were induced by the great earthquake, despite no significant damages to the other three dams. The Zipingpu CFRD with the maximum dam height of 156m is the highest embankment dam located in the high seismic intensity region during the Wenchuan earthquake and is also the first CFRD experiencing strong shallow earthquake of IX–X degrees in the world. In this paper, the engineering properties, earthquake-induced damages and monitoring results of the Zipingpu CFRD are described in details. Its aseismic characteristics are analyzed from the following aspects: 1) basic features of earthquake damages, 2) deformation characteristics, 3) evaluation of earthquake damages, 4) aseismic performance, 5) ground motion, 6) weak parts of seismic resistance, and 7) repairability performance. A brief introduction to the damage to the Bikou dam is also made. These are expected to be beneficial to the understanding of the seismic behavior of high embankment dams subjected to strong earthquakes.