System Reliability Analysis of a High Concrete-Faced Rockfill Dam Considering Creep Effects and Hydro-Mechanical Coupling

Abstract:

This paper proposes a method for the system reliability analysis of high concrete-faced rockfill dam （CFRD）， considering creep effects and hydro-mechanical coupling. To obtain the joint failure probability of CFRD in multiple failure modes， the total probability formula is used to express the failure probability of the dam system as the product of the failure probability of the face slab and the conditional probability of seepage failure after slab failure. The instantaneous deformation， consolidation deformation， and long-term creep are calculated by the Duncan-chang E-B model， the Biot consolidation theory， and an improved Merchant model， respectively. Considering the uncertainty of the parameters and the time factors of rockfill creep and reservoir water level fluctuation， the system reliability of the dam is calculated. The method is applied to the 233 m high Shuibuya CFRD. The results show that the consolidation deformation is completed in the construction and initial storage stages， and the deformation produced during the operation of the dam is mainly creep deformation. During the initial storage， the slab failure probability and the seepage failure probability after the slab failure increase sharply， resulting in an obvious reduction in the reliability of the dam system. During operation， the increase in creep deformation leads to a gradual decrease in the reliability of the slab and the dam system. As the creep deformation gradually converges， the reliability of the dam system tends to be stable after a slow decline.