摘要
为探究崩岗土壤宽吸力范围(0~10 MPa)土壤水力学特性,以崩壁红土层、砂土层和碎屑层土壤为研究对象,采用压力膜仪法和滤纸法测定崩壁不同土层土壤的持水能力,用传统Van Genuchten-Mualem模型(传统VG模型)和修正Van Genuchten-Mualem模型(修正VG模型)对土壤水分特征曲线进行拟合分析。结果表明:采用压力膜仪法和滤纸法测定的持水曲线存在交点,相交后两种方法的持水曲线趋于重合,联合两种测定方法可以获得宽吸力范围的土壤水分特征曲线。在宽吸力范围内,低吸力阶段(h<0.1 MPa),砂土层土壤的持水能力高于红土层和碎屑层土壤,而在高吸力阶段(h≥0.1 MPa),红土层土壤持水能力最高。崩壁各土层土壤水分特征曲线采用传统VG模型和修正VG模型拟合程度均较高,均方根误差均低于0.0215,纳什效率系数值和相关系数分别大于0.9266和0.8991,且修正VG模型更适合描述宽吸力范围崩壁土壤水分特征曲线。红土层、砂土层和碎屑层土壤水分特征曲线的残余值分别为:378 kPa(对应含水率为18.82%)、173 kPa(对应含水率为18.95%)和92 kPa(对应含水率为18.41%)。相对于传统VG模型,采用分段函数的形式(以残余值为拐点)更适合描述宽吸力范围崩岗土壤的非饱和导水率。
To investigate the soil hydraulic characteristics across a wide range of suctions(0-10 MPa)of Benggang soil,the soil water holding capacities of different soil layers in Benggang was determined using the pressure film meter and the filter paper methods.Traditional and modified Van Genuchten⁃Mualem(VG)models were used to fit the soil moisture characteristics curves.The results showed that the water⁃holding curves determined by the pressure film meter and filter paper methods intersected and tended to overlap.This observation suggested combining the two measurement methods to obtain soil moisture characteristic curves over a wide suction range.Further,within the wide suction range,the water⁃holding capacity of the sandy soil layer was higher than that of the red and detritus soil layers in the low suction stage(h<0.1 MPa).However,in the high suction stage(h>0.1 MPa),the red soil layer had the highest water⁃holding capacity.Both the traditional and modified VG models were able to fit the soil moisture characteristics of each soil layer of the Benggang wall with a root mean square error of less than 0.0215.The Nash efficiency and correlation coefficients were greater than 0.9266 and 0.8991,respectively.Noticeably,the modified VG model was more suitable for describing the soil moisture characteristic curves of the Benggang wall across a wide suction range.The residual values of the soil moisture characteristic curves for the red,sandy,and detritus layers were 378 kPa(corresponding to a water content of 18.82%),173 kPa(corresponding to a water content of 18.95%),and 92 kPa(corresponding to a water content of 18.41%),respectively.Finally,the form of the segmental function(with the residual value as the inflection point)was more suitable for describing the unsaturated hydraulic conductivity over a wide suction range of Benggang soils than the conventional VG model.
作者
杨茂进
张越
施梦璐
杨雨珂
黄炎和
YANG Maojin;ZHANG Yue;SHI Menglu;YANG Yuke;HUANG Yanhe(College of Resources and Environment,Fujian Agriculture and Forestry University,Fuzhou,Fujian 350002,China)
出处
《森林与环境学报》
CSCD
北大核心
2023年第4期433-441,共9页
Journal of Forest and Environment
基金
国家自然科学基金“水-热耦合效应下崩壁土壤抗剪强度变化特征与机制研究”(41907043)
福建省水利科技项目“崩岗崩壁防塌生态治理技术研发与示范”(KJg21009A)
福建农林大学科技创新专项基金“不同形态氧化铁对崩岗土壤抗剪强度影响的微观机制研究”(CXZX2020074A)。
关键词
崩岗
压力膜法
滤纸法
土壤水分特征曲线
模型评价
非饱和导水率
Benggang
pressure membrane method
filter paper method
soil moisture characteristic curve
model evaluation
unsaturated hydraulic conductivity
