基于微结构参数主成分的黄土湿陷性评价

黄土的湿陷性与其微观结构特征密切相关，它的微结构又受其应力状态和所处的含水状态影响。通过改变含水率与固结压力，对西安原状黄土进行了湿陷性试验，由此分析了不同含水率与固结压力条件下湿陷性的差异与联系，同时通过电镜扫描（SEM）获取了湿陷前、后黄土试样的微结构照片，进而获取了相应条件下的SEM照片的简单微结构参数。分析了湿陷前、后微结构参数的变化，探讨了简单微结构参数间相关关系，基于主成分分析法构建了合成微结构参数。研究表明：随着固结压力的增大，颗粒体所占比重越来越大，第1主成分近似线性增大，黄土湿陷系数与其累积主成分呈线性关系。根据这一重要认识，建立了主成分得分的湿陷系数计算方法，进而建立了黄土湿陷性评价方法。该研究对定量研究黄土湿陷性的微结构效应做了有益的探索。

Evaluation of loess collapsibility based on principal components of microstructural parameters

The collapsibility of loess is closely related with its microstructural character,which is directly affected by the stress state subjected and its moisture condition.The collapsible tests of the intact loess from Xi’an with various water contents and consolidation pressures were carried out.The differences and relations of collapsibility of loess under various conditions were analyzed based on the results of these tests.The scanning electron microscope(SEM) images were obtained both on loess samples of before and after collapsing;then corresponding microstructural parameters were obtained.Comparative analysis of simple microstructural parameters was made.The relationship among these parameters was discussed and the synthetic microstructural parameters were constructed as well.The results indicate that the proportion of particle and the first principal component increases with the increase of consolidated pressure;there is a linear relationship between collapsibility and the first principal component of loess.Based on this understanding,the calculation method of collapse coefficient is established.The collapsibility of loess can be evaluated objectively using the proposed method.The efficient exploration is made in quantificational studying the effects of microstructure on collapsibility of loess.