关键词: 土-水特征曲线, 非饱和土, 影响因素, 模型, 残余含水率

Abstract:

Pressure plate apparatus and GDS unsaturated triaxial apparatus are used to study the influences of compaction work, compaction water content, dry density, stress history and sample stress state on SWCC of unsaturated remolded clay. Through least-square method, Van Genuchten model, Fredlund tri-parameter model and Fredlund quadr-parameter model are employed to fit SWCC. The results show that each model can fit to the experimental data well. Through analyzing the influencing factors, it is found that not only physical condition of samples but also external stress condition can affect the shape of SWCC. The result shows the higher compaction work, higher compaction water content, higher dry density, longer stress history and higher net mean stress are, the higher air entry value is; and the water is more difficult to be discharged from soil samples. In high matric suction range, it seems that the influents of influencing factors on the shape of SWCC are reduced. Through comparing the residual water contents between Fredlund tri-parameter model and Fredlund quadr-parameter model, it is found that the residual water content has little effect on SWCC; it means the assumption that the residual water content is zero is right.

Key words: soil-water characteristic curve, unsaturated soil, influencing factor, model, residual water content