崩岗土壤液塑限的离子特异性效应OA北大核心CSTPCD

Liquid and plastic limits are important parameters of soil hydraulic properties and are important in the research of collapsing gullies. To investigate the specific ion effects on the liquid and plastic limits of collapsing gullies,soil samples from three soil layers in a soil profile (red soil layer,sandy soil layer,and detritus layer) of a stable collapsing gully located in Hetian Town of Changting County,Fujian Province,were collected and exchanged with three kinds of electrolyte solutions (Li+,Na+,and K+) to analyze the liquid and plastic limits. The main results were as follows:the red soil layer had the highest plastic limit,liquid limit,and plasticity index,followed by the sandy soil and detritus layers (P<0.05). Correlation analysis showed that the clay content,organic matter content,cation exchange capacity,and kaolinite content were positively correlated with the plastic and liquid limits (P<0.05) . Clay and organic matter contents were significantly positively correlated with the plastic limit. The plastic limit,liquid limit,and plasticity index of the red soil layer exchanged with K+were 5.80％,9.53％,and 12.99％ higher than those exchanged with Li+,and 3.50％,9.77％,and 15.86％ higher than those exchanged with Na+,respectively. The plastic limit,liquid limit,and plasticity index of the sandy soil layer exchanged with K+were 7.22％,6.69％,and 6.83％ higher than those exchanged with Li+,and 4.33％,5.27％,and 7.32％ higher than those exchanged with Na+,respectively. However,the liquid and plastic limits of the detritus layers did not differ significantly. The liquid and plastic limits of the red and sandy soil layers exchanged for K+were significantly higher than those exchanged for Li+and Na+. Therefore,compared with Li+and Na+,K+could increase the liquid and plastic limits of collapsing gullies.