Abstract:

An analysis procedure based on shear strength reduction finite element method for pseudo-static seismic stability calculation of earth and rockfill dam (ERFD) is presented. In the proposed procedure, two methods are proposed to determine the seism-induced inertia force: (1) the inertia forces are computed with the same method adopted in the pseudo-static limit equilibrium slices method; (2) with the absolute acceleration response of element nodes obtained from the finite element dynamic response analysis of the dam, the inertia forces corresponding to the node acceleration are computed with the proposed empirical method. With the inertia forces achieved above, the self-gravity, and/or the forces corresponding to the seepage force or dynamic pore water pressure, the elastoplastic finite element analysis is conducted to achieve the pseudo-static factor of safety of the dam by reducing the effective shear strength parameters of soil until the limit equilibrium is reached. Finally, numerical computations are conducted to illustrate the proposed analysis method; and the results are compared with those obtained from the pseudo-static limit equilibrium method. It is concluded that the utilization of the finite element method for aseismic stability analysis of ERFD is feasible.

Key words: earth and rockfill dams, pseudo-static seismic stability analysis, strength reduction finite element method, elastoplastic finite element analysis