黄河大堤非饱和土土-水特性试验研究

模拟工程中非饱和土体的实际受力状态,利用改进的非饱和土三轴仪对黄河大堤非饱和土在不同围压条件下的土-水特性进行了试验研究。根据试验结果,分析了黄河大堤非饱和土体在外荷作用下土-水特征曲线及其变化规律。并对相应的土-水特征曲线模型进行了拟合,得出其拟合函数。根据土-水特征曲线可知,非饱和土的基质吸力随着土体所受周围压力的增大而减小,随着含水量的增大而减小;对于某一类土而言,在高含水量(含水量>20 %) 时,土的基质吸力随含水量的变化较小,而在低含水量 (含水量≤20 %)时,土的基质吸力随含水量的变化较大。随着含水量的增加,非饱和土的工程性质向弱性变化。

Test and study on soil water curve of unsaturated soil of Yellow River dyke

With the improved triaxial equipment for unsaturated soil, we tested and studied soil water characteristics of Yellow River dyke’s unsaturated soil under different confining pressures simulating the real condition exposed on unsaturated soil in engineering. And according to fest results, the curves of soil-water characteristics of unsaturated soil are obtained and the water-soil characteristics and their rules under additional load are discussed. At the same time, the function of fitted curves is gained. Based on the water-soil curves, the results are known that the matric suctions reduce with increasing the surrounding pressure and water content. To the same type soil, the matric suction changes small with change of water content when the water content is higher than 20 %, but it changes greatly when the water content is less than 20 %. The engineering characteristics become weak with increasing water contents.