Plastic-Damage Thin-Layer Element Model for Seismic Failure Analysis of Concrete Dams

Finite element methods based on the small deformation assumption have been widely used in the seismic response analysis of concrete dams. However, these methods are not effective in simulating the entire process of concrete dams transitioning from small deformation damage cracking to larger deformation collapse under extreme earthquake events. This paper proposes a plastic-damage thin-layer element model for analyzing large deformation failure of concrete dams under strong earthquakes. Using the equivalence principles, the smeared crack model is equivalently transformed into a layered separation format, which can consider both small and large deformations. Numerical verification through single thin-layer elements and Petersson's three-point bending beam demonstrates that the proposed model can comprehensively consider plastic deformation, damage, and stiffness changes in concrete. Furthermore, the seismic failure process of Koyna gravity dam is simulated using the proposed plastic-damage thin-layer element method. The results show that this model can realistically simulate the entire process from initial cracking to ultimate failure in concrete dams.