Abstract:

Time-history analysis using dynamic FEM is employed to compute the seismic response of Ahai concrete gravity dam at the Jinsha River subjected to design earthquake loading. The hydrodynamic pressures and dam-foundation interaction are considered in the FEM model; and the foundation radiation damping effect of the seismic motion energy dissipating towards infinite domain is simulated as well. Firstly, the complex numerical simulation results are validated by comparison of dam body’s maximum inertial forces between time-history analysis and spectrum method. Then, the following evaluation of the sliding stability of the dam can be conducted. The time history of anti-sliding safety factor is obtained using stress integration along the dam-base sliding interface. Because the minimum value of safety factor histories is 1.146; it can be concluded that the Ahai dam has a relatively enough high capability for earthquake resistance that the reinforcement to improve the anti-sliding stability is not needed. The outcome of this study should be of interest and useful to professionals involved in the design of similar large gravity dams.

Key words: Ahai hydropower station at Jinsha River, concrete gravity dam, seismic sliding stability, time-history analysis, stress integration method, transient value of the sliding safety factor