多年冻土场地桩基桥梁地震响应不确定性量化分析

Uncertainty quantification of seismic response of a pile-supported bridge in the permafrost region

该研究采用多年冻土场地桩基桥梁数值模型和高斯过程替代模型进行多年冻土场地桩基桥梁地震响应不确定性量化分析。首先,利用试验设计方法构建多年冻土场地桩基桥梁高斯过程替代模型的训练样本,生成结构体系输入参数的最大数量采样点;针对采样点,利用建立的桩基桥梁有限元数值模型进行非线性地震响应分析,使用高斯过程替代模型模拟多年冻土场地桩基桥梁输入和输出关系,进而执行桩基桥梁的不确定性量化。基于统计变量和变异参数(coefficient of variation, COV)评估多年冻土场地桩基桥梁地震响应的不确定性。研究结果表明:(1)当桥梁结构参数随着变异参数由5%增加为30%时,桥梁结构的时程响应随之而增加,桥梁结构输入参数的变异性对多年冻土场地桩基桥梁的地震响应影响显著;(2)随着桥梁结构体系输入参数变异性增加,相应的地震响应的变异性随之增加,桥梁结构体系输入参数变异性增加直接影响地震响应变异参数的变化。该研究中所述多年冻土场地桩基桥梁地震响应不确定性量化分析可为同类构筑物的模拟提供分析方法和思路。

In this study, uncertainty quantification of seismic response on a pile-supported bridge structure in a permafrost region was carried out based on the finite element numerical model and seismic response characteristics of the pile-supported bridge structure in the permafrost region. Firstly, the training samples of a surrogate model for the pile-supported bridge structure in the permafrost region were constructed using an experimental design method, which was used to generate maximum number of sampling points for uncertainty parameters. A Gaussian process surrogate model was used to simulate input-output relationship for physical processes of the pile-supported bridge structure in the permafrost region, and then a reduced order surrogate model was used to perform uncertainty quantification. Seismic response uncertainty of the pile-supported bridge structurein the permafrost region was assessed based on statistical variables and variational parameters.Results show that:(1) As coefficient of variation(COV) increases from 5% to 30%, time history response of the bridge structure consequently increases correspondingly. The parameter uncertainty of the bridge structure has a significant effect on seismic response of the pile-supported bridge structurein the permafrost region.(2) As the COV of input parameters for the bridge structure are increased, the corresponding COV of seismic response is also increased. This indicates that the COV increase of input parameters for the bridge structure directly affects the COV of seismic response. The uncertainty quantification analysis of the pile-supported bridge structure in the permafrost regiondescribed in this study can provide analytical methods and ideas for the simulation of similar structures.