非饱和重塑黄土土-水特征曲线与渗透系数模型预测

The Prediction Model Research of Soil-water Characteristic Curve and Permeability Coefficient of Unsaturated Remolded Loess

在分析土-水特征曲线及预测非饱和土渗透系数方法的基础上,以甘肃兰州重塑黄土为研究对象,采用非饱和土固结仪,测定初始饱和度相同、干密度不同的土样的土-水特征曲线,基于拟合效果较好的Fredlund&Xing三参数方程对试验数据进行拟合.以实测的土-水特征曲线为基础,采用Childs&Collis-Geroge预测非饱和渗透系数的模型,计算得到非饱和黄土渗透系数与基质吸力的关系,结果表明:渗透系数随吸力的增大呈非线性减小,两者的关系可用幂函数表示,这为黄土地区土体工程性质的研究和预测,如降雨入渗的边坡稳定性评价、非饱和地基湿陷变形计算等提供了理论支持.

Based on the analysis of soil water characteristic curve and prediction method of permeability coefficient, this paper takes remolded loess in Lanzhou of Gansu province as research objects. Soil water characteristic curve is obtained from the unsaturated soil consolidation apparatus, and the experimental data are then fitted with Fredlund＆Xing Equation which has a better fitting effect. With the use of permeability prediction on Childs＆Collis-Geroge Model, the relationship between permeability coefficient and matrix suction is built on the strength of the measurement of soil-water characteristic curve. The results show that the permeability coefficient decreases along with the nonlinear increase of the matrix suction, and they can be expressed in power function. It provides theoretical support to the research and prediction of engineering properties in loess area, such as slope stability evaluation under rainfall infiltration and the calculation of collapsibility deformation for unsaturated foundation.