A Comparative Study of Seismic Stability of Coupled Arch Dam-foundation-reservoir Systems Using Infinite Elements and Viscous Boundary Models

In the present paper, a direct time domain procedure is used for dynamic structural stability analysis of the dam-reservoir-foundation coupled system in 3D space considering the impact of the ground motion duration. The foundation medium is assumed to be massed and infinite elements are used for modeling the semi-infinite medium of the foundation. The nonlinear behavior of mass concrete is modeled using the coaxial rotating smeared crack approach with the ability of cracking at Gaussian points. The reservoir is assumed to be compressible and is modeled using fluid finite elements. In order to investigate the effects of the ground motion duration on dynamic stability of the coupled system, a set of artificially-generated ground motions with different duration but the same intensities are used to analyze the system. It is found that the responses of the system with the massed foundation including either infinite elements or viscous boundary on the far-end face of the foundation are the same. Using the massless foundation leads to conservative stresses within dam body. Implementation of the infinite elements leads to decreasing crack profile of the concrete dam compared to the massless model; however higher duration ground motions lead to more damage in both models.