大孔隙对土壤比水容重及非饱和导水率影响的实验研究

Effects of Macropore on Soil Specific Water Capacity and Unsaturated Hydraulic Conductivity

以南京市栖霞区东阳镇的粉砂壤土为例,用土壤水分特征曲线(van Genuchten模型)拟合包含大孔隙原状土、不包含大孔隙扰动土的实测数据,得到了模型参数,进而得到比水容重和非饱和导水率与土壤含水量之间关系的表达式,在此基础上对比分析了原状土与扰动土水分运动参数之间的异同,并着重分析了土壤大孔隙对其影响。结果表明,受土壤大孔隙的影响,在同一含水量的情况下,扰动土的比水容重比原状土大1～2个数量级,并且随着吸力的增大,二者的差值逐渐减小;扰动土的非饱和导水率小于原状土,最大可相差2～3个数量级。

Take the silt loam soil of Dongyang town of Qixia district of Nanjing city for example,the van Genuchten model parameters of soil water characteristic curve were obtained by fitting measured date of undisturbed soil which include macropore and disturbed soil which not include macropore.Then,expressions of soil specific water capacity and unsaturated hydraulic conductivity were obtained.On this basis,comparative analysis is made with the soil water movement parameters＇ similarities and differences of undisturbed soil and disturbed soil,and emphatically analysised the influence of macropore to them.The results showed that,due to the effect of soil macropore,with the same soil water content,the specific water capacity of disturbed soil is 1 to 2 order of magnitude larger than undisturbed soil,and the difference of them is decreasing with the soil water suction increasing,the unsaturated soil hydraulic conductivity of disturbed is less than undisturbed soil,the difference maybe 2 to 3 order of magnitude.