非水相流体(NAPLs)在黄土中的持留特征研究

试验测定了粘土和砂土二种土壤在不同容重下水气、PCE气和水NAPL的毛管压力与饱和度的关系曲线。研究发现,容重对二种土壤毛管压力与饱和度关系有明显影响,随着容重的增大,束缚水饱和度和进气值或置换压力增加;相同容重下,重壤土的束缚水饱和度大于砂壤土的,而砂壤土残留PCE含量大于重壤土。根据压力与饱和度的关系曲线,三者之间存在一定相关性达到极显著水平。但由于毛管压力与饱和度关系曲线在多相流研究中极为重要,因此在可能的情况下尽可能采用试验手段进行测定。

Experimental Study of Retention Characteristic of NAPLs in Loess

A laboratory measurement of capillary pressure-saturation curve of three systems, water-air、PCE-air and water-NAPL, for heavy loam and sandy loam at different bulk density is introduced in this paper. It is shown that bulk density has remarkable effect on the capillary pressure-saturation curve for the two soils. With the increase of bulk density, the residual water and PCE saturation and displacement pressure increase. The irreducible water saturation of heavy loam is larger than that of sandy loam at the same bulk density, while the residual PCE saturation to the contrary. Based on Leverett function, the capillary pressure-saturation between the two phases of water-air、PCE-air and water-PCE are related significantly and can be generalized to a uniform curve. However, because of the importance of capillary pressure-saturation, the relation of aspect is expected to be obtained experimentally.