重塑非饱和黏土的土-水特征曲线及其影响因素研究

采用常规压力板仪和GDS非饱和土三轴仪，详细研究了击实功、击实含水率、干密度、应力历史和试样应力状态5种因素对非饱和重塑黏土土-水特征曲线的影响。并采用Van Genuchten模型、Fredlund 3参数模型和Fredlund 4参数模型，通过最小二乘法对所测土-水特征曲线进行拟合。结果表明，这3种模型均可对土-水特征曲线进行较好的拟合。通过对这个5种不同影响因素的分析，发现不仅试样本身物理状态而且试样外部应力状态都对土-水特征曲线有重要的影响，即击实功越大、击实含水率越高、干密度越大、试样的应力历史越大、所受净平均应力越高，则试样的进气值越高，水越难从试样中排出。在较高的基质吸力范围内，各种因素对土-水特征曲线的影响作用有减小的趋势。通过Fredlund 3参数模型和Fredlund 4参数模型的残余含水率对比分析可知，残余含水率对模型的参数值影响不大，即假定残余含水率 为0是合理的。

Experimental study of soil-water characteristic curve of remolded unsaturated clay

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.