Relationship between the Hydraulic Conductivity Function and the Particle‐Size Distribution
Relationship between the Hydraulic Conductivity Function and the Particle‐Size Distribution
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DOI：
10.2136/sssaj2003.3730
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发表时间：
2003
影响因子：
2.9
通讯作者：
L. Arya;F. Leij;P. Shouse;M. Genuchten
中科院分区：
文献类型：
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作者：
L. Arya;F. Leij;P. Shouse;M. Genuchten
我们提出了一个模型来计算水力传导度K，作为水分的函数θ，直接从土壤的颗粒分布(Psd)。该模型假定土壤孔隙可以用等效毛细管来表示，并且水流速度是孔隙大小的函数。用Arya-Paris模型由PSD得到了孔尺寸分布。利用16种土壤的粒度分布和K(θ)数据，用Qi=crix来关联孔隙流速和孔隙半径，其中qi是孔隙流速(cm3 S-1)，ri是孔隙半径(Cm)。对数c从约-2.43变化到约2.78，而x从2.66变化到=4.71。然而，这些参数并没有随着质地的变化而呈现出系统的变化趋势。利用该模型对另外16个土壤的θ数据进行了K(PSD)函数的独立计算。该模型预测了从接近饱和到极低含水率的K(θ)值。单样K(θ)预测值与实验值的一致性从好到差，砂土的对数转换K(θ)的均方根残差(RMSR)为0.616~1.603，壤土为0.592~1.719，粘土为0.487~1.065。所有纹理的平均均方根比为0.878。
We present a model to compute the hydraulic conductivity, K, as a function of water content, θ, directly from the particle-size distribution (PSD) of a soil. The model is based on the assumption that soil pores can be represented by equivalent capillary tubes and that the water flow rate is a function of pore size. The pore-size distribution is derived from the PSD using the Arya-Paris model. Particle-size distribution and K(θ) data for 16 soils, representing several textural classes, were used to relate the pore flow rate and the pore radius according to q i = cr i x , where q i is the pore flow rate (cm 3 s -1 ) and r i is the pore radius (cm). Log c varied from about -2.43 to about 2.78, and x varied from 2.66 to = 4.71. However, these parameters did not exhibit a systematic trend with textural class. The model was used to independently compute the K(θ) function, from the PSD data for 16 additional soils. The model predicted K(θ) values from near saturation to very low water contents. The agreement between the predicted and experimental K(θ) for individual samples ranged from excellent to poor, with the root mean square residuals (RMSR) of the log-transformed K(θ) ranging from 0.616 to 1.603 for sand, from 0.592 to 1.719 for loam, and from 0.487 to 1.065 for clay. The average RMSR for all textures was 0.878.