System dynamic reliability evaluation of multiple failure modes of earth dams subjected to strong earthquake excitation

Abstract

An earth dam in service is a complex system that has different dynamic failure modes under different ground motion excitations with a certain correlation between the different failure modes. However, because of the nonlinear dynamic coupling effect of the randomness of the earthquake ground motion and the nonlinearity of the geotechnical parameters, traditional deterministic analyses cannot adequately consider the failure mechanisms of earth rock dams subjected to earthquake excitation, resulting in unexpected and uncontrollable local failure modes or weak failure areas; this makes the seismic dynamic performance of earth rock dams subjected to strong earthquake excitation non-optimal. Accordingly, the main dynamic failure modes and failure mechanisms of earth rock dams under seismic dynamic action are studied based on the nonlinear stochastic dynamics method and the first passage theory, combined with a time-domain nonlinear dynamic time-history analysis. Our results indicate that the seismic dynamic reliability of earth dam under ground motion excitation is far less than that under different single failure modes. Seismic reinforcement or heightening measures based on the overall seismic dynamic reliability can be used to effectively resist strong earthquake disasters encountered by earth rock dams in the future and optimize the seismic dynamic performance of earth rock dams.

Keywords

• Multiple failure modes
• Global dynamic reliability
• Nonlinear seismic dynamic response
• Earth dam
• Liquefaction site