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首页> 外文会议>Flood Forecasting and Water Resources Assessment for IAHS(International Association of Hydrological Sciences)-PUB >A Method for Estimating Soil Hydraulic Properties of Unsaturated Soils by Generalized Richards Equation
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A Method for Estimating Soil Hydraulic Properties of Unsaturated Soils by Generalized Richards Equation

机译：用广义理查兹方程估算非饱和土的水力性质的方法。

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Simulations of water transport in soil are ubiquitous and the Richards equation introduced in 1931 is the main tool for that purpose. For experiments on water transport in soil horizontal columns, Richards equation predicts that volumetric water contents should depend solely on the ratio (distance)/(time)~q where q = 0. 5. Substantial experimental evidence shows that value of q is significantly less than 0. 5 in some cases. The corresponding mathematical model is a generalized Richards equation partial deriv~γθ/ partial deriv~γt= partial deriv/ partial deriv x[k(h) partial deriv h/ partial deriv x] where, γ is the order of the fractional derivative; and k is unsaturated hydraulic conductivity function. Van Genuchten (1980) obtain a expression of k(h):k(h)=k_s[1-(α|h|~(n-1))/[1+(α|h|)~n]~(1-1)]~2/([1+(α|h|)~n]~(1-1)~(1/2))where, α and n are two parameters. In this paper, a new method for estimating α and n using both generalized Richards equation and the closed form equations of soil hydraulic properties is proposed. The two parameters, α and n are estimated by the characteristic length of wetted zone, sorptivity and saturated hydraulic conductivity.
机译：土壤中水运移的模拟无处不在，并且1931年引入的理查兹方程是实现此目的的主要工具。对于水平土中水运移的实验，理查兹方程预测，体积水含量应仅取决于（距离）/（时间）〜q之比，其中q =0。5.大量实验证据表明，q值明显小于在某些情况下大于0。5。相应的数学模型是广义的Richards方程。偏导数γθ/偏导数γt=偏导数/偏导数x [k（h）偏导数h /偏导数x]其中，γ是分数阶导数的阶； k为不饱和导水率函数。 Van Genuchten（1980）获得k（h）：k（h）= k_s [1-（α| h |〜（n-1））/ [1+（α| h |）〜n]〜（ 1-1 / n）]〜2 /（[1+（α| h |）〜n]〜（1-1 / n）〜（1/2））其中，α和n是两个参数。本文提出了一种利用广义Richards方程和土壤水力学闭合形式方程估算α和n的新方法。 α和n这两个参数是根据湿区的特征长度，吸水性和饱和导水率估算的。

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