土壤與地下水汙染的汙染物可能留存在非飽和層而未滲入地下水，殘存汙染物質和入滲雨水的互動將影響地表作物用水及地下水質。 本研究利用以Pore doublet model和以Micro X-Ray CT所掃描之真實孔隙剖面影像為孔隙幾何製成的微模型，研究在不同的蒸發時間 (不同初始水量) 下新舊液體的交替過程，觀察殘留液體與新液體之間的互動機制。 研究發現在雙通道微模型實驗中，液體殘留越多，越不容易在新液體注入時被排退。在真實孔隙微模型實驗中，薄膜水的減少，造成舊液體殘餘增加。介質結構越密集越容易產生孤立區，進而阻擋新液體地進入。 由於雙通道與真實孔隙的孔隙結構不同，殘餘液體形成機制也不同，造成兩組實驗結果有顯著差異，顯示過度簡化模型可能產生完全不同的研究結論。;Once the surface pollutants leak into soil and subsurface, they can remain in the unsaturated layer (vadose zone) without being permeated into groundwater. The interaction between the residual contaminants and infiltrating rainwater or irrigation water will affect the water usage of crops and the groundwater quality. In this study, by using the micromodels with patterns of pore doublet and real 2D pore geometry scanned by Micro X-Ray CT, I studied the alternation process of the old and new fluids subject to different evaporation times (with different initial water volumes) and observed the interaction mechanism between residual and incoming liquids. The results found that, in the pore-doublet micro-model experiment, the more liquid remains, the less likely it is to be discharged when the new liquid was infused. With micromodel of 2D pore geometry, the reduction of film water increased the old liquid residues. The denser the media structure is, the more likely it is to produce isolated areas, which blocked the entrance of new liquids. Because of the difference of opening structure between the pore doublet and the real pore geometry, the formation mechanism of the residual liquid will be different, contributing to the substantial differences in the experimental outcomes of the two groups, indicating that the oversimplified model may produce completely different study conclusions.