【摘要】 为探讨包气带深部增厚区土壤水力参数变化对入渗补给过程的影响,采用压力膜仪对河北正定深部包气带(8.0~21.0m)10个原状土样进行水分特征曲线测试,利用RETC软件中Mualem-van Genuchten导水率模型对其拟合,获取含水率与非饱和导水率的关系曲线,并根据达西法对其进行分析讨论.结果表明:场地包气带深埋区的非饱和导水率为25~240mm/a.当某一埋深历史水位下降速度越快,该埋深处相同含水率情况下土壤非饱和导水率越大,说明对应土层的入渗补给强度越大;因包气带厚度增大使原来位于饱水带的层状非均质土层转变为包气带,潜水位波动下降过程中深部包气带土层因排水压密作用,使得土壤水力特性发生变化,进而影响垂向入渗补给过程.更多还原

【Abstract】 Ten undisturbed soil samples were collected from deep vadose zone(8.0-21.0m)at Zhengding,Hebei,and analyzed to study how thickening vadose zone impacts the infiltration recharge processes.These samples were measured by Pressure Plate Extractor to gain the soil retention curves,which were fitted by Mualem-van Genuchten Model using RETC software.Unsaturated hydraulic conductivity and the relation curves were obtained through the curve-fitting processes.The impact on the infiltration recharge processes at the thickening vadose zone is discussed according the Darcy’s equation.It is concluded that the unsaturated hydraulic conductivities at sampling time were 25-240mm/a at the depth of 8.0-21.0m.If the velocity of water table decline was fast at a certain depth historically,the unsaturated conductivities with same water content should also have large values,which shows the soil has large infiltration capacity.Soil hydraulic parameters and infiltration capacities would change because of water table fluctuated-declining and drainage consolidation,which would impact vertical infiltration recharge.更多还原