张岩, 陈国兴, 赵凯, 彭艳菊, 江志杰, 杨文保. 海洋土动剪切模量比和阻尼比预测不确定性特性[J]. 工程力学, 2023, 40(5): 161-171. DOI: 10.6052/j.issn.1000-4750.2021.10.0832
引用本文: 张岩, 陈国兴, 赵凯, 彭艳菊, 江志杰, 杨文保. 海洋土动剪切模量比和阻尼比预测不确定性特性[J]. 工程力学, 2023, 40(5): 161-171. DOI: 10.6052/j.issn.1000-4750.2021.10.0832
ZHANG Yan, CHEN Guo-xing, ZHAO Kai, PENG Yan-ju, JIANG Zhi-jie, YANG Wen-bao. UNCERTAINTIES OF SHEAR MODULUS REDUCTION AND DAMPING RATION CURVES OF MARINE SOILS[J]. Engineering Mechanics, 2023, 40(5): 161-171. DOI: 10.6052/j.issn.1000-4750.2021.10.0832
Citation: ZHANG Yan, CHEN Guo-xing, ZHAO Kai, PENG Yan-ju, JIANG Zhi-jie, YANG Wen-bao. UNCERTAINTIES OF SHEAR MODULUS REDUCTION AND DAMPING RATION CURVES OF MARINE SOILS[J]. Engineering Mechanics, 2023, 40(5): 161-171. DOI: 10.6052/j.issn.1000-4750.2021.10.0832

海洋土动剪切模量比和阻尼比预测不确定性特性

UNCERTAINTIES OF SHEAR MODULUS REDUCTION AND DAMPING RATION CURVES OF MARINE SOILS

  • 摘要: 土体动剪切模量比G/Gmax和阻尼比λ随剪应变幅值γa的变化曲线的不确定性对场地非线性地震反应分析结果的不确定性有重要影响。以莱州湾海床110 m以浅的原状粉质黏土试样G/Gmaxλ的试验数据为例,采用Davidenkov骨架曲线描述G/Gmax曲线,λ表示为小应变阻尼比λminG/Gmax的函数,发现描述G/Gmax曲线的参数ABγrλmin的预测方程均为海床深度H的函数。基于点估计法的不确定性传递分析表明,参数ABγr三者的不确定性共同引起的预测G/Gmax的总体不确定性以及仅由单一参数ABγr值的不确定性引起的预测G/Gmax的单变量不确定性均随γa的增大而先增大后减小。预测G/Gmax的总体不确定性和仅由Bγr的不确定性引起的预测G/Gmax的单变量不确定性均随H的增加而降低;参数A的不确定性引起的预测G/Gmax的单变量不确定性随H的增加而增大。由G/Gmaxλmin两者的不确定性引起的预测λ的总体不确定性以及仅由G/Gmax的不确定性引起的预测λ的单变量不确定性均随γa的增大而略有先增大后减小的趋势,且均随H的增大而略有减小。由λmin的不确定性引起的预测λ的单变量不确定性与γa无关且随H的增大而略有增大。

     

    Abstract: The uncertainties of soil shear modulus reduction (G/Gmax) and damping (λ) increase curves with shear strain amplitude (γa) have important influence on the uncertainty of the results of nonlinear site seismic response. Based on the test data of undisturbed marine silty clay samples taken from seabed surface to 110 m depth at the Laizhou Bay, the G/Gmax curve is described using the Davidenkov skeleton curve function, and the λ curve is expressed as a function of two variables, i.e., the λmin (small strain damping) and G/Gmax. The laboratory investigation reveals that the prediction equations of parameters A, B, and γr, which describe the G/Gmax curve and λmin, are all functions of the seabed depth H. The uncertainty transfer analysis based on point estimation method shows that the total uncertainty of the predicted G/Gmax caused by the parameters A, B, and γr and the single univariate uncertainty of the predicted G/Gmax caused by one of the three parameters increase first and then decrease with γa. The total and univariate uncertainty of the predicted G/Gmax caused by the variable B or γr decrease with H, whereas the univariate uncertainty of the predicted G/Gmax caused by the variable A increases with H. The total uncertainty of the predicted λ caused by G/Gmax and λmin and the univariate uncertainty of the predicted λ caused by G/Gmax increase slightly first and then decrease slightly with γa, while both decrease slightly with H. The univariate uncertainty of the predicted λ caused by λmin is independent of γa and increases slightly with H.

     

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