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題 名 | 線性入滲問題於不飽和有地下水位之解析解=Analytical Solution of Infiltration Problem of Unsaturated Soil with Groundwater Level Without Gravitation |
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作 者 | 陳建謀; 黃漢誠; 陳主惠; 譚義績; | 書刊名 | 農業工程學報 |
卷 期 | 44:2 1998.06[民87.06] |
頁 次 | 頁59-76 |
分類號 | 351.8 |
關鍵詞 | 積水時間; 入滲曲線; 土壤體積含水比剖面; Ponding time; Infiltration curve; Water content profile; |
語 文 | 中文(Chinese) |
中文摘要 | 入滲曲線之求法傳統上可利用數值解、經驗公式及解析解,數值解會有質量平衡 的問題產生誤差,有些經驗公式則是忽略臨前水文條件之影響,而前人所探討之解析解約未 考慮於產生漫地流前後不同的起始條件進行求解,本文假設Diffusivity為常數情況下,考慮 一維及二維有地下水位之情形下,針對積水前後求解Richards equation,並以台北地區十年 及一百年頻率之降雨強度下求出壤土及砂土之積水時間、入滲曲線及土壤體積含水比剖面。 基本上一維及二維之結果變化趨勢相同,相同土壤其積水時間隨土壤的D值之增大而增大, 隨降雨強度之增大而減少,隨地下水位深度之增大而增大,臨前水文條件越乾燥則積水時間 越長;相同土壤於不同降雨強度下,降雨強度越小積水時間越長,但整個含水層達飽和之時 間尺度則相近;而地下水位對整個含水層達飽和之時間之影響則是地下水位越深所需之時間 越久。不同土壤其入滲曲線除了積水時間不一樣外,其變化則以砂土較快達入滲率為零,壤 土較慢。本文二維部分之研究可供應用於模擬大樓開挖前,打入鋼版椿或連續壁施工後降雨 之狀況,推估其初始積水時間及未積水前之體積含水比分佈。 |
英文摘要 | Traditionally, solutions of infiltration curve have, numerical solution, experienced formula and analytical solution. Numerical solution and experienced formula may not be so correct because of mass balance and neglect the antecedent condition. Previous analytical solutions have neglected the difference of initial condition during overland flow happened and before. In this paper, we will solve one dimensional and two dimensional problems of unsaturated soil with groundwater level and assumption of constant diffusivity. Considering the differences of initial condition the Richards equation is adopted as governing equationo to get the analytical solution of ponding time, infiltration curve and water content profile. The trend of results in both one dimensional and two dimensional problem are similar. For the same soil, ponding time is proportional to diffusivity, distance of ground water level and initial water content. Ponding time is inverse proportional to rainfall intensitity. The tie needed to get the whole aquifer saturated have similar order for same soil and initial water content with different rainfall intensitity. For different soil, take sand and silty loam as examples, it takes longer tie for silty loam to have the infiltration rate close to zero. The result of two dimensional problem can be applied to predict the ponding time and water content profile before ponding when foundation of a building is digging. |
本系統中英文摘要資訊取自各篇刊載內容。