考虑尿素浓度对SWCC影响的VG模型

利用Tempe压力膜仪,进行了不同浓度尿素溶液的土-水特征曲线(SWCC)试验,得出了不同SWCC的Van Genuchten(VG)拟合模型。结合各VG模型,采用线性回归分析,确定了模型中各参数与尿素浓度的关系,进而建立了能够考虑尿素浓度影响的VG模型。所得模型中各参数拟合相关度均较高。由所建模型可知,尿素浓度对参数α影响较小,而对参数n影响较大;浓度越大,参数α越小,而参数n越大。所得结果弥补了其他方法不能考虑尿素浓度对SWCC的影响,对补充和发展SWCC试验和理论具有一定的意义。所建SWCC模型未考虑尿素浓度对溶质吸力的影响,也未开展尿素溶液对土体SWCC影响机理研究;这两方面有待以后的工作进一步研究。

A VG model considering influence of urea concentration on SWCC

The experimental studies of the soil-water characteristics curves(SWCC) have been carried out using different urea concentrations， with Tempe pressure membrane apparatus. And the experimental results are fitted by Van Genuchten (VG) model. Based on these VG models， the relationships between parameters of VG models and the urea concentration are obtained by linear regression. Finally， a new VG model considering the impacts of the urea concentration on SWCC is established in the experimental studies. The new model shows that the urea concentration effects parameter n is larger than a parameter α； the higher the urea concentration is， the smaller the parameter α is and the larger the parameter n is. The studies have made up for the deficiency of other methods which can not consider the urea concentration, and are very significant for the supplement and development of the theory and the experimental methods of SWCC. SWCC model developed by the authcrs does not consider the effects of the urea concentration upon the solute suction, nor the influence mechanism of the urea colution on the soil-water characteristics curves. The two issues have to be further studied in the future.