水溶性阳离子在工程黄土中的扩散特性

Diffussion Characteristics of Water Soluable Cations in Engineering Loess

该文采用水平扩散池观测了水溶性盐阳离子在工程黄土中的扩散过程。结果表明：水溶性盐阳离子在土壤中的扩散特性因离子种类而异，Ｃａ２＋的扩散系数最高，Ｍｇ２＋，Ｎａ＋，Ｋ＋依次降低，其由两个模型测定的平均值分别为２．６９２８×１０－６，２．３１２７×１０－６，１．６７３０×１０－６，０．４５０４×１０－６ｃｍ２／ｓ。在距源溶液较近时，土壤胶体交换性Ｋ＋，Ｎａ＋，Ｍｇ２＋均明显升高，特别是交换性Ｋ＋升高幅度最大；而交换性Ｃａ２＋却明显减少，说明Ｋ＋，Ｎａ＋，Ｍｇ２＋被土壤胶体吸附，而Ｃａ２＋不但没有吸附，反而被解吸。

Horizontal diffussion cells were used to observe and measure the diffussion processes of the water soluable salt cations in engineering loess. The results obtained showed that the diffussion characteristics of every cation changed with its variety. The diffussion coefficient of Ca2+ was the highest, and that of Mg2+, Na+ and K+ dropped in turn. The mean values of them determined in the two models were 2.692 8×10-6, 2.312 7×10-6,1.637 0×10-6 and 0.4504×10-6cm2/s respectively. The significant increase of the exchangeable K+, Na+ and Mg2+, and the decrease of the exchangeable Ca2+ in soil near the source solution indicated that the formers were absorpted and the later was desorpted by the soil collision.