非饱和黏性粉土的土水特征曲线试验研究

Experimental study on soil-water characteristic curve of unsaturated clayey soil

为研究净平均应力和干密度对非饱和黏性粉土土水特征曲线的作用规律,采用实验和理论分析的方法,进行土水特征曲线试验,按修正的VanGenuchten模型进行拟合并得出公式,提出其对土水特征曲线的作用机理.研究结果表明:净平均应力增大,导致土体结构密实,进气值增大,排水性变低;干密度增大,孔隙尺寸缩小,气液两相接触面曲率减小,进气值所需压力变大;修正后的VanGenuchten模型较好地描述土水特征曲线,拟合度较高.研究结论揭示了非饱和黏性粉土土水特征曲线的变化规律,为非饱和黏性粉土的路基、桥梁等工程提供理论依据.

In order to study the effect of net mean stress and dry density on the characteristic curve of unsaturated viscous silt,the characteristic curve of soil and water was tested by experiment and theoretical analysis.The results show that the increase of mean average stress leads to the compactness of soil structure,the increase of air intake and the decrease of water drainage.The dry density increases,the pore size decreases,the curvature of the contact surface of gas-liquid two phase decreases,and the pressure required for the inlet value increases.The modified VanGenuchten model described the characteristic curve of soil and water well with a high fitting degree.The study results reveal the variation law of soil-water characteristic curve of unsaturated viscous silt,and provide theoretical basis for subgrade and bridge engineering of unsaturated viscous silt.