依据对黄土地层的孔隙度及颗粒组分等实测资料 ,初步认识到黄土的孔隙度具有从上向下波动减小的规律 ,波峰在黄土层 ,而波谷在古土壤层 ,也即黄土的孔隙度大于古土壤。黄土主要由粉砂、粘粒构成 ,并且黄土的粒度比古土壤要粗一些。黄土的孔隙度与黄土的颗粒组成具有相关关系 ,决定孔隙度大小的主导因素是颗粒大小 Based on the measured data of porosity and particle composition of loess stratum, it is preliminarily recognized that the porosity of loess has the rule of decreasing from top to bottom. The crest is in the loess layer, while the trough is in the paleosol layer, that is, the loess pore Degree greater than the ancient soil. Loess is mainly composed of silt and clay, and the loess has a larger grain size than the paleosol. The porosity of loess is related to the grain composition of the loess. The dominant factor determining the size of the loess is the grain size