基于改进溶质吸力方程的含盐土毛细水迁移规律研究

Study on Capillary Water Rise in Saline Soils Based on Improved Solute Suction Equation

在特殊土地区,毛细水和盐的共同作用极易导致冻胀、盐胀等路基病害。含盐量较高的土壤中,溶质吸力作为重要驱动因素影响毛细水上升。在分析现有溶质吸力计算不足的基础上,提出适用于含有单价离子电解质溶液的溶质吸力系数确定方法,并验证其精度和适用性;基于毛细孔径分布模型理论,提出能体现盐分作用的毛细最大上升高度预测方法并验证其适宜性。研究结果表明,针对含NaCl和Na_(2)SO_(4)土壤的溶质吸力计算公式相较于经典公式具有更高的准确性,NaCl和Na_(2)SO_(4)的存在对基质吸力会产生影响,吸力曲线随着盐含量的增加有增大的趋势,其对溶质吸力的影响更大;该预测方法能够较好体现盐分在毛细上升高度的贡献。

In special soil areas,the combined action of capillary water and salt can easily cause roadbed damages such as frost heave and salt heave.In soils with high salt content,osmotic suction as an important driving factor has a great influence on capillary upwelling.Based on the analysis of the shortcomings of existing formulas for calculating osmotic suction force,the calculation formula of osmotic suction coefficient for monovalent ionic electrolyte solution was proposed and its accuracy and applicability were verified.Based on the theory of capillary diameter distribution model,a prediction method of maximum capillary height which can reflect the effect of salt was proposed and verified.The results show that the calculation formula of osmotic suction for soils containing NaCl and Na_(2)SO_(4)has better accuracy compared with the classical formula.The presence of NaCl and Na_(2)SO_(4)affects the matric suction.The suction curve tends to increase with the increase of salt content,with a greater impact on osmotic suction.The prediction method of maximum capillary rise height based on soil pore distribution theory can better reflect the influence of salt on capillary rise height.