考虑多源土工试验数据的土体参数概率化估计研究

    Probabilistic prediction of soil parameters based on multi-source geotechnical test data

    • 摘要: 针对水下岩土工程勘察数据有限,难以构建合适的土体参数估计模型以确定可靠的土体参数的问题,首先建立了包含10种土体参数的数据库,其次采用分层贝叶斯模型从数据库充足的数据中学习和提取定量信息,结合目标场地有限的测试数据,构建目标场地的多元参数概率分布,从而估计目标场地土体参数,并研究了目标场地数据量和数据种类对参数估计的影响。结果表明,在勘察数据有限且含有缺失值的情况下,利用分层贝叶斯模型可确定土体参数的统计特征和概率分布,实现对参数的准确估计;该方法对目标场地数据量要求低,只需少量数据即可有效降低参数估计的不确定性;结合压缩系数、压缩模量和液塑限数据,可有效降低黏聚力和内摩擦角的估计不确定性。

       

      Abstract: To address the challenge of determining reliable soil parameters in cases with limited underwater geotechnical investigation data, a database involving ten soil parameters is established. Based on a hierarchical Bayesian model (HBM), quantitative information is learned and extracted from the abundant data in the database. By incorporating the constructed database with the limited test data from the target site, a quasi-site-specific multivariate probability distribution of soil parameters is constructed to improve the prediction accuracy of unknown soil properties for the target site. The effects of the quantity and types of data on soil parameter estimation are also investigated. The results indicate that HBM can provide the statistical characteristics and probability distribution of the target soil parameters, and accurately estimate them even with limited and incomplete geotechnical data from the target site. Only a small amount of data is required to effectively reduce estimation uncertainty. Moreover, using the compressibility coefficient, compression modulus, liquid limit, and plastic limit to predict cohesion and friction angle can effectively reduce prediction uncertainty.

       

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