土-水特征曲线在黄土边坡稳定分析中的应用研究

以南水北调中线穿黄工程南岸连接渠边坡为研究对象，采用压力板法获得了非饱和黄土边坡的土-水特征曲线，用Van Genuchten模型对试验数据进行了拟合，将拟合参数代入Vanepalli非饱和土的抗剪强度经验公式，预测不同吸力和含水率下的非饱和土的抗剪强度值，并与常吸力三轴剪切试验结果进行对比，验证了预测公式的准确性；试验结果和预测结果都表明非饱和黄土吸力和含水率的变化对黏聚力影响显著，对内摩擦角影响较小。通过建立含水率与非饱和黄土抗剪强度的关系，将不同含水率的抗剪强度运用到非饱和黄土边坡稳定性分析中，不但能对该区域黄土边坡的稳定性给予科学的评价，还可以减少不必要的浪费。

Application of SWCC in Stability Analysis of Loess Slope

The slope along the connecting canal on southern bank to Yellow River crossing tunnel on mid-line of south-to-north water diversion project was taken as the study object herein, and the soil-water characteristic curve (SWCC) of unsaturated loess slope was obtained by means of pressure plate with the test data processed by Van Genuchten model. The fitting parameters were put into the Vanepalli empirical formula of unsaturated soil to predict the shear strength under different suction and moisture content and then compare with the result of triaxial shear test under constant suction; the accuracy of prediction formula was then verified. The results of the test and prediction show that the variation of suction and moisture content of unsaturated loess have considerable influence on the cohesion, but less on the internal friction angle. By means of setting up the relation of moisture content vs. shear strength, the shear strength under different moisture content may be included into the stability analysis of unsaturated loess slope, which can not only scientifically evaluate the stability of loess slope in this region, but also avoid unnecessary wastes.