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Ground motion, geotechnical materials, and structural materials are three primary sources of aleatory uncertainty in the seismic design and assessment of underground structures. However, the effects of the latter two have often been ignored, which brings doubts about the rationality of the design and evaluation results. In this paper, based on the probability density evolution method (PDEM), the non-linear stochastic seismic analyses and reliability analyses under multi-source uncertainty conditions were carried out for a metro station structure in soft soils, and the effects of three aleatory uncertainty sources were explored. Random variable models were established to quantify the involved aleatory uncertainties of non-linear materials. The results showed that for underground structures, the uncertainty of geotechnical materials is nonnegligible, and the influence level of the uncertainty of it is close to that of ground motion, because it not only changes the soil-structure relative stiffness, but also changes the deformation mode of strata, resulting in both an increase in the elastic reliability and a decrease in the elastic-plastic reliability. The aleatory uncertainty source of structural materials changes the soil-structure relative stiffness, but has little effect on the lateral deformation response and elastic-plastic reliability of the station structure.

Underground structures, Probability density evolution method, Aleatory uncertainty sources, Dynamic response, Seismic reliability