场地有限数据条件下土体不排水抗剪强度的概率分布的贝叶斯估计研究  

Bayesian estimation of probability distributions of undrained shear strength of soils with limited site data

作　　者：张德 张泽超 张璐璐[1,3,4] 张洁 曹子君[6] ZHANG De;ZHANG Zechao;ZHANG Lulu;ZHANG Jie;CAO Zijun(State Key Laboratory of Ocean Engineering,Department of Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Institute of Science and Technology,China Three Gorges Corporation,Beijing 100038,China;Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration(CISSE),Shanghai 200240,China;Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure,Shanghai 200240,China;Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;MOE Key Laboratory of High-Speed Railway Engineering,Institute of Smart City and Intelligent Transportation,Southwest Jiaotong University,Chengdu 611756,China)

机构地区：[1]上海交通大学土木工程系海洋工程国家实验室,上海200240 [2]中国长江三峡集团有限公司科学技术研究院,北京100038 [3]高新船舶与深海开发装备协同创新中心,上海200240 [4]上海市公共建筑和基础设施数字化运维重点实验室,上海200092 [5]同济大学地下建筑与工程系,上海200092 [6]西南交通大学智慧城市与交通学院高速铁路线路工程教育部重点实验室,四川成都611756

出　　处：《岩土工程学报》2023年第6期1259-1268,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家重点研发计划项目(2021YFB2600700);中国长江三峡集团有限公司科研资助项目(WWKY-2020-0741);国家自然科学基金项目(52025094,51979158);上海市教育委员会科研创新计划(2021-01-07-00-02-E00089)。

摘　　要：针对勘察数据有限或不完备条件下设计参数取值不可靠的问题,建立了包含141个场地共1679组数据的黏性土参数数据库,分别采用基于单个场地数据的特定场地贝叶斯方法(SBM)和可综合利用多场地数据的层次贝叶斯方法(HBM)对黏性土不排水抗剪强度的概率分布进行参数估计。结果表明,与SBM方法相比,在场地仅有少量实测数据的情况下HBM方法能有效降低参数估计的不确定性,且受数据量影响小。采用留一交叉验证法(LOO-CV),结合点预测密度的对数值(lppd)比较了上述两种方法的准确度,结果表明HBM方法的lppdloo-cv指标更大,整体预测准确度更高。因此,HBM方法比SBM方法更适用于场地有限数据情况下不排水抗剪强度概率分布的参数估计,且HBM方法得到的后验统计值还可用于新场地的参数估计。To address the issue of poor reliability of the design parameters due to limited or incomplete geotechnical investigation data,a cohesive soil parameter database containing 1679 sets of data from 141 sites is established.The site-specific Bayesian method(SBM)and the hierarchical Bayesian method(HBM)are used to estimate the probability distribution of undrained shear strength of cohesive soils by utilizing the data from a specific site and multiple sites,respectively.The results show that compared with the SBM method,the HBM method can effectively reduce the uncertainty of parameter estimation when there is only limited measured data at the target site,and it is less affected by the number of measuring points at the target site.The leave-one-out cross-validation(LOO-CV)combined with the log pointwise predictive density(lppd)is used to compare the accuracy of the two methods.The results show that the lppdloo-cv index of the HBM method is larger,indicating that the overall prediction accuracy of the HBM method is higher.Therefore,the HBM method is more suitable for the estimation of undrained shear strength parameters in the case of limited site data,and the posterior means obtained by the HBM method can be used for parameter estimation of new sites.

关 键 词：层次贝叶斯方法 多元正态分布 参数估计 交叉验证 不排水抗剪强度 

分 类 号：TU43[建筑科学—岩土工程]