中文摘要：

通过分析土体自然历史形成条件,从土性参数变异性表现特征着手,对其进行归类分析,初步回答了土性指标变异性的含义;对比分析了土层剖面的两种建模方法,据此提出了基于随机场理论的变异性统计方法,并通过实际工程勘探数据的统计分析,诠释了该方法的优越性所在。结果表明：土性指标变异性并非土体分层后层与层之间土性指标的差异,而是层内土性点与点之间的空间变异;相对于传统随机变量的建模方法,这种空间变异性用随机场理论建模更加科学合理;随机场理论用空间趋势函数和随机波动分量分别表征土性指标的确定性部分和随机扰动部分,通过去趋势化处理,可把握土性参数不确定性的核心;实例分析显示,本文提出的方法可更加精确地了解土性参数的不确定性,为可靠性理念在实际工程中的应用提供有利的途径。

英文摘要：

Based on the nature-history formation conditions of the soil, variability of the soil behaviors is classified in terms of features and the meanings of＂variability＂ are completely clarified. Two modeling methods of soil profiles are compared, and a statistical method of soil variability based on the random field theory is recommended. Simultaneously, a statistical case of analyzing actual engineering investigation data is performed to interpret the superiority of the method. It indicates that the meanings of ＂variability＂ are not the difference between layers of soil mass, and that it should be the deviation from point to point in the same soil layer, and can be modeled by the random field theory that is more scientifical than the traditional random variable. The statistical method focuses on considering the distillate of soil variability by separating the certain component that can be depicted by the function of trend and the disturbance component that can be characterized by the random fluctuation efficiently. The study case reveals that the present method will grasp the uncertainties of soil parameters more accurately and provide a favorable way to apply reliability-based design approach in geotechnical engineering.