Seismic stability of earth-rock dams using finite element limit analysis: Fid-Bau Portal

Seismic stability of earth-rock dams using finite element limit analysis

Yang, Xin-guang / Chi, Shi-chun

Abstract In this study, a finite element limit analysis method is developed to assess the seismic stability of earth-rock dams. A pseudo-static approach is employed within the limit analysis framework to determine the lower and upper bounds on the critical seismic coefficients of dams. The interlocking force in the soil is considered, and the rockfill material is assumed to follow the Mohr–Coulomb failure criterion and an associated flow rule. Based on the native form of the failure criterion, the lower and upper bound theorems are formulated as second-order cone programming problems. The nonlinear shear strength properties of rockfill materials are also considered. The developed finite element limit analysis is applied to two different types of earth-rock dams. The results indicate that the rigorous lower and upper bounds are very close even for rockfill materials with large internal friction angles. The failure surfaces are easily predicted using the contour of the yield function and the displacement field obtained by the limit analysis method. In addition, the pore water pressures are modelled as external forces in the limit analysis to assess the seismic stability of earth-rock dams in the reservoir filling stage.

Highlights • The limit analysis method is shown to be a powerful tool for calculating the critical acceleration of earth-rock dams. • Both the linear and nonlinear properties of the shear strength of rockfill materials are considered in this paper. • The seismic stability of earth-rock dams is analysed in both the construction and reservoir filling stages. • The results are in very good agreement with those obtained using Bishop׳s simplified method.