2-D elastoplastic seismic shear response of earth dams: Theory

A simplified analytical-numerical method for analyzing the nonlinear earthquake response of earth dams, modeled as two-dimensional, nonhomogeneous shear wedges in rectangular canyons, is presented. The method takes into account the nonlinear, hysteretic, and strain-dependent characteristics of the dam materials. The hysteretic stress-strain behavior of the material is modeled using elastoplastic constitutive equations based on multisurface kinematic plasticity theory; no viscous or numerical (artificial) damping is employed. The method is based on a Galerkin formulation of the equation of motion in which the solution is expanded using the eigenmodes of the two-dimensional linearized problem defined over the spatial domain occupied by the dam. The analysis can be used to calculate the entire time history of the response quantities, including permanent deformations of earth dams subjected to ground shaking. Finally, the efficiency and low computational cost make the technique very attractive.