Non-linear seismic behaviour of concrete gravity dams and travelling wave effect along reservoir bottom
14 December 2010
In the present article, the effect of non-uniform excitation of a reservoir bottom on the non-linear response of concrete gravity dams is considered. An anisotropic damage mechanics approach is used to model the non-linear behaviour of mass concrete in a two-dimensional space. The reservoir is assumed to be compressible, and the foundation mass is taken into account in analyses conducted utilizing the appropriate boundary condition on the far end truncated boundary of the foundation medium. The system of dam-reservoir massed foundation is solved using the staggered displacement method. The tallest monolith of the Pine Flat dam in California, US, is selected as a case study, and the horizontal and vertical components of India’s 1967 Koyna earthquake are used to excite the system. It is found that the crest response and stresses within the dam body decrease significantly when the reservoir is excited non-uniformly in the two cases of rigid and massed foundation. In addition, the crack profiles in the heel of the dam body decrease in analyses conducted with massed foundation.
