基于BUS方法的无限长边坡可靠度更新

发布时间：2018-05-15 06:46

本文选题：边坡可靠度 + 贝叶斯更新　；参考：《岩土力学》2017年12期

【摘要】：某一特定岩土场地的试验数据、监测资料和观测信息等通常十分有限,然而贝叶斯方法却可充分利用有限的场地信息克服试验数据样本量较小的不足。为有效估计有限样本条件下参数统计特征,提出了基于结构可靠度方法和贝叶斯更新(BUS)的边坡可靠度更新方法,通过融入直剪试验数据更新无限长边坡可靠度验证了提出方法的有效性,并系统探讨了岩土体参数先验信息如试验样本量、概率分布和似然函数模型对边坡可靠度更新的影响规律。结果表明:BUS方法能够考虑岩土体参数概率分布和似然函数模型的影响,融入有限的场地信息准确地估计参数统计特征和更新边坡可靠度,为解决有限样本条件下边坡可靠度更新问题提供了一条有效的途径。土体参数概率分布对边坡可靠度更新结果(参数后验均值、标准差以及更新的失效概率)具有重要的影响,基于常用的正态和对数正态分布的边坡可靠度更新结果偏于保守,相比之下,似然函数模型对边坡可靠度更新结果的影响相对较小。此外,岩土体参数不确定性和更新的边坡失效概率均随着试验样本量的增大而减小,但当样本量增大到一定程度时它们的变化不大。
[Abstract]:The test data, monitoring data and observation information of a particular geotechnical site are usually very limited. However, the Bayesian method can make full use of the limited site information to overcome the shortage of small sample size of test data. In order to effectively estimate the statistical characteristics of parameters under the condition of finite samples, a slope reliability updating method based on structural reliability method and Bayesian update method is proposed. The validity of the proposed method is verified by updating the infinite slope reliability by incorporating the direct shear test data, and the prior information of rock and soil parameters such as the sample size of the test is discussed systematically. The influence of probability distribution and likelihood function model on slope reliability update. The results show that the probability distribution of rock and soil parameters and the influence of likelihood function model can be taken into account by using the W-BUS method, which can accurately estimate the statistical characteristics of parameters and update the slope reliability by incorporating limited site information. It provides an effective way to solve the problem of slope reliability renewal under the condition of limited sample. The probability distribution of soil parameters has an important influence on the slope reliability update results (parameter posteriori mean, standard deviation and renewal failure probability). The slope reliability update results based on normal distribution and logarithmic normal distribution are conservative. In contrast, the likelihood function model has relatively little effect on the slope reliability update results. In addition, both the uncertainty of rock and soil parameters and the failure probability of the updated slope decrease with the increase of the sample size, but when the sample size increases to a certain extent, the change of them is not significant.
【作者单位】：南昌大学建筑工程学院;中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室;
【基金】：国家自然科学基金项目(No.51509125,No.51679117) 岩土力学与工程国家重点实验室开放基金项目(No.Z016014) 江西省自然科学基金项目(No.20171BAB206058) 中国科协青年人才托举工程项目~~
【分类号】：TU43

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