Time-varying effect of stochastic factors on flood safety of dams and their quantitative evaluation methods

The flood safety of dams is subjected to various stochastic factors.With the elapse of time,those factors having negative impact on the flood control safety are of obvious time-varying characteristics.The time-varying characteristics of flood control of dams due to this effect,both the impact of mild change effect and steep change effect,are demonstrated,then the time-varying characteristics of various stochastic factors during the dam ageing as well as their effect on flood safety are analyzed.With regard to the following 3 kinds of stochastic factors during the long-term operation of dams:settlement of dam top,deposition of sediment and failure of flood releasing gates,the quantitative evaluation methods,that is,attenuation function approach,comprehensive analysis approach and Bayesian approach,are put forward.