PLT26 - Numerical Modeling and Simulation of Seismic Response of a Concrete Faced Rockfill Dam Measured in Dynamic Centrifuge Tests

Concrete-Faced Rockfill Dams (CFRDs) have generally performed well during earthquakes, though limited records exist on their performance during major seismic events. The damage sustained by the Zipingpu CFRD during the 2008 Wenchuan earthquake is a notable instance that raised significant concerns regarding the seismic design of CFRDs. The damage mechanisms included a combination of crest settlements, horizontal displacement, concrete face cracking, and joint dislocations. To evaluate the seismic response of CFRDs, empirical calculations and advanced numerical simulations are utilized. Empirical methods provide a preliminary evaluation of various damage mechanisms but are generally separate calculations for each mechanism and challenging to generalize due to limited case histories and the unique response of each dam to specific earthquakes, influenced by its design features and the earthquake's characteristics. On the other hand, advanced numerical models allow for dam- and earthquake-specific simulations, evaluating the system-level response accounting for interaction between different components. However, the efficacy of the computational tools developed for these analyses needs assessment. This study evaluates the performance of a newly developed computational toolbox for three-dimensional finite element analysis of nonlinear and seismic water-soil-structure interaction in CFRDs. The toolbox facilitates detailed modeling of the interactions among water, rockfill, and the concrete face. The study compares numerical simulation results with experimental data using results from a dynamic centrifuge test “case history”. The comparison indicates that with increasing levels of shaking, the assumptions regarding rockfill material modeling and the accounting for interactions between rockfill, concrete, and water become crucial. The numerical simulation results demonstrate that incorporating advanced features for seismic soil modeling, and addressing sliding and gapping between CFRD components, leads to a better estimation of experimental results across a range of earthquake intensities. The toolbox is useful for advanced, dam-specific seismic analysis and evaluation of CFRDs located in areas at high risk of earthquakes, especially where initial screenings indicate seismic concerns.