岩土参数的不确定性及其统计方法

Uncertainties of soil properties and its statistical methods

通过诠释土性参数不确定性统计工作的重要性,着手分析、对比了各种统计方法的理论基础和优越性,随后基于近年来国内外相关文献的回顾与整理,系统地总结了有关土性参数变异性方面的研究成果,具体包括试验室指标参数、变形参数、强度参数、固结参数以及原位测试中的静力触探测试值、十字板剪切强度和标准贯入击数。结果表明:传统方法和三σ法都是基于随机变量理论,无论如何改进也无法克服模型本身所固有的缺陷;基于随机场理论的方法用更加优越的模型建模土层剖面,显示了强大的生命力,随着原位测试手段的日渐成熟,这一方法必将取代传统方法;图形三σ法集理论先进性和适用性于一体,是一种值得推荐的方法。参数变异性的总结显示,试验室指标参数变异性普遍较小、固结参数较大、变形和强度参数以及原位测试各指标位于其中,具体结果还对实际工程中参数的选取、优化以及部分重要工程的可靠性分析具有重要的指导意义。

Based on interpreting the importance of statistical work of soil parameters,uncertainties,the theoretical foundations and superiorities of many statistical methods are analyzed and contrasted.The research results about soil variability are summarized systematically via reviews and collections of the involved literatures at home and abroad,including index parameters,deformation parameters,strength parameters,consolidation parameters of lab tests and the parameters from CPT,VST and SPT.It is shown that the traditional method and the three-sigma rule,which are both based on the random-variable theory,will never overcome defects of model itself in spite of improvements in any case.The random field-based approaches model the soil profiles by superior random field theory and show strong vitality.It will replace the traditional method along with gradually mature of in situ tests finally.The graphical three-sigma rule,converging theoretical advance and applicability,is a worthy recommended method.The results of soil variability show that the variations of laboratory index parameters are small,the laboratory consolidation parameters are big and the other parameters from lab tests and in situ tests are in the middle.The results also show significance for selecting and optimizing parameters and reliability analysis of some important projects.