陕西渭北黄土浸水饱和前后孔隙变化规律

Pore Changes of Loess Before and After Water Saturation in Weibei,Shaanxi Province

为探求天然黄土浸水饱和前后孔隙变化的规律,以天然及浸水饱和后的陕西渭北黄土为例,分别进行压汞试验、扫描电镜试验、粒度分析试验,研究了原状黄土的微观结构及浸水饱和前后孔隙变化特性。结果表明,天然及浸水饱和两种状态土体均含有大量椭圆状颗粒,其点接触为颗粒间连接的主要形式,同时也存在微胶结形式,架空孔隙存于土体内部,并伴有镶嵌孔隙;浸水饱和后由于水的溶解作用等原因,黄土孔隙体积、比表面积均大于天然黄土;同时探讨了黄土在不同状态下的孔隙特性,进一步揭示了孔隙变化与湿陷性的关系。

In order to explore the law of pore changes before and after water saturation in natural loess,this paper takes the natural and water-saturated loess of Shaanxi Weibei as the research objects.The mercury intrusion test,scanning electron microscopy test and particle size analysis test were carried out to study the microstructure of undisturbed loess and the characteristics of pore change before and after water saturation.The results show that the soil in both natural and water-saturated states contains a large number of elliptical particles.The point contact is the main form of inter-particle connection,and there is also a form of slightly cemented.The overhead pores exist in the soil and are accompanied by mosaic pores.After saturated with water,the pore volume and specific surface area of loess are larger than natural loess,owing to the dissolution of water.At the same time,the pore characteristics of loess in different states are discussed,and the relationship between pore change and collapsibility is further revealed.