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題名 | 以理查氏方程式數值解比較常用入滲公式=Assessment of Infiltration Formulas Based on Numerical solution of Richards' Equation |
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作者姓名(中文) | 許少華; 倪春發; | 書刊名 | 中國土木水利工程學刊 |
卷期 | 11:2 1999.06[民88.06] |
頁次 | 頁327-336 |
分類號 | 443.67 |
關鍵詞 | 入滲; 地下水未飽和層; Richards方程式; Infiltration; Vadous zone; Richards equation; |
語文 | 中文(Chinese) |
中文摘要 | 本研究以解析解驗證過的雙步驟Crank-Nicolson數值方法,在適當的邊界條件下 求出Richards方程式在上邊界(地表)的解作為標準的入滲率,並以此檢驗較常用的入滲容 量(capacity)公式:Horton(1933)、Philip(1957)及Green-Ampt(1911)式。經比較各種入滲 率與入滲量的結果顯示,以入滲率而言,Horton式與數值解的差距較大,Philip式及Green- Ampt式則非常密合,累積入滲量則三者皆與數值解密合。對改變雨量強度及土壤臨雨前的起 始含水量兩例條件而言,入滲公式之若干參數迴歸值變異甚大。作預測時入滲公式中的k值 (包括Horton式的f 值)在任何條件下皆近似於土壤之飽和水力傳導係數k ,其他參數值則 需推敲決定,此顯示了入滲公式之侷限性。 |
英文摘要 | The Richards equation is used as the flow equation for one-dimensional percolation flow within unsaturated topsoil and is solved by the two-step Crank- Nicolson scheme. Under constant water supply, the Darcy's velocity obtained at the upper boundary, i.e., the ground surface, is treated as infiltration rate. Based on this, three infiltration-capacity formulas, including Horton's, Philip's, and Green-Ampt's, are evaluated. Results show that Horton's formula deviates most compared to the other two in terms of the infiltration rate. For cumulative infiltration depth, all formulas behave well. By changing the rainfall intensity and initial soil moisture content, the regression result shows that the saturated hydraulic conductivity k can be used as a good estimate of the k (f ) value in all formulas. The fact that the other parameters will deviate from their original values, indicates the superiority of the numberical method. |
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