Seismic stability analysis of a high arch dam-foundation system considering ground motion and modeling parameter uncertainties

Abstract

In this research, seismic stability uncertainty analysis of a high arch dam-foundation system is investigated considering ground motion and modeling parameter uncertainties. Ground motions and modeling parameters of shear strength on the potential sliding block of dam abutment are chosen as random variables in the probabilistic and statistic framework. Taking a high arch dam as a case study, a total number of 1000 nonlinear dynamic analyses are performed using incremental dynamic analysis (IDA) and Latin hypercube sampling (LHS). The peak ground acceleration (PGA) is taken as intensity measure (IM) and the residual sliding displacement and sliding area ratio are adopted as seismic sliding stability performance evaluation indexes, respectively. Comparative analyses are presented to discuss the effect of only modeling parameter uncertainty, only ground motion uncertainty, and both uncertainties on seismic sliding stability of the high arch dam-foundation system. The results reveal that obvious variability of seismic sliding stability of the high arch dam-foundation system is observed due to the existence of ground motion and modeling parameter uncertainties and it is sensitive to PGA. The variability owing to both ground motion and modeling parameter uncertainties is more remarkable compared with that caused by only one single uncertainty. Moreover, the ground motion uncertainty shows a more obvious impact on the variability of residual sliding displacement, while the modeling parameter uncertainty has a more notable effect on the variability of sliding area ratio. Therefore, it is necessary to consider both two kinds of uncertainties for seismic stability safety evaluation of a high arch dam-foundation system in the probabilistic and statistic framework.