垃圾土渗透性和持水性的试验研究

Laboratory and field tests on hydraulic properties of landfilled waste

通过室内常水头试验测定了垃圾土的饱和渗透系数,通过室内压力板仪试验测得垃圾土的土-水特征曲线。基于土-水特征曲线预测了垃圾土的非饱和渗透系数,并通过室内入渗试验进行了初步验证。常水头试验得到深层、中层和浅层垃圾土的饱和渗透系数分别为3.56×10-4、3.50×10-3、4.81×10-2cm/s。土-水特征曲线试验表明,垃圾土饱和含水率和残余含水率较高,进气值很小,土-水特征曲线在低基质吸力时存在陡降段,其中浅层垃圾土的陡于深层垃圾。验证试验表明,预测得到的非饱和渗透系数与实测结果接近,基于土-水特征曲线预测垃圾土非饱和渗透系数的方法基本可行。

Saturated hydraulic conductivity of landfilled waste was measured by laboratory tests. Soil-water characteristic curve （SWCC） of landfilled waste was measured using a ceramic plate extractor. A method to predict unsaturated hydraulic conductivity of landfilled waste based on its SWCC was proposed and was verified by a laboratory test. Saturated hydraulic conductivities of landfilled wastes in shallow, middle and deep depth of a landfill are measured to be 4.81×10^-2cm/s, 3.50×10^-3cm/s and 3.56×10^-4cm/s, respectively. The results of SWCC tests show that the saturated and residual water content of landfilled wastes are high and that the SWCC curve is steep when matric suction is relatively low. The unsaturated hydraulic conductivity predicted using the proposed method is verified by an infiltration test. The result illustrates the feasibility of the proposed method.