流體流經多孔隙介質間之化學反應及後續所造成多孔隙介質水力傳導特性的改變之研究在科學、工業與工程等各領域都受到重視，溶解與沉澱反應為影響流體化學性質的的兩個最重要過程，且其將改變多孔隙介質之物理與化學性質。本計畫之主要目的為探討由於地球化學之溶解與沉澱反應所造成之多孔隙介質孔隙率與水力傳導特性的改變，計畫中首先利用一組偶合地下流體流動、化學物種傳輸與地化反應之聯立控制方程組建立數值模式，數值模式將藉由序列迭代法結合有限差分求解聯立控制方程組，計畫中將在不同的情境考慮下探討由於地化之溶解與沉澱反應所造成之多孔隙介質水力傳導特性的改變，此外計畫中將進行一系列之實驗室砂箱模型試驗。本計畫第一年探討只有溶解反應發生時，單一局部初始不均質孔隙率分佈存在時，多孔隙介質水力傳導特性之變化；第二年探討只有溶解反應發生時，兩處局部初始不均質孔隙率分佈存在時，多孔隙介質時水力傳導特性之發展；第三年探討考探討同時有溶解與沉澱反應發生時，單一或兩處局部初始不均質孔隙率分佈存在時，多孔隙介質時水力傳導特性之發展與演變現象，本計畫結果將有助於預測地下流體中化學物種之遷移與釐清瞭解自然界包括石灰巖地層礦脈之生成。 Investigation of chemical reactions between a fluid and the porous medium through which it flows, and of the subsequent changes in the medium hydraulic conductivity, is an area of interest for many scientific, industrial and engineering. Dissolution and precipitation are two of the most important processes affecting of fluid chemistry, and they can significantly modify the physical and chemical properties of porous media. The objective of this project is to investigate the changes in porosity and hydraulic conductivity affected by geochemical dissolution/precipitation in porous media. The numerical model will be constructed using a set of coupling governing equations of fluid flow, chemical species transport and geochemical reactions. The sequential iteration approach coupling with implicit finite difference method will be adopted to solve the set of coupling governing equations. A series of numerical simulations will be conducted to investigate the evolution of porosity and hydraulic conductivity due to dissolution and precipitation between a fluid and the porous medium under various scenarios. Additionally, a series of laboratory sandbox experiments will be executed to study experimentally the change in porosity and hydraulic conductivity and to compare the results with those from numerical simulations. In the first year, the evolution of hydraulic conductivity affected by only dissolution in a porous medium with a single initial small, local non-uniformity will be investigated. In the second year, the evolution of hydraulic conductivity affected by only dissolution in a porous medium with two initial small, local non-uniformities will be analyzed. In third year, the evolution of hydraulic conductivity affected by simultaneous dissolution/precipitation in porous medium with a single or two initial small, local non-uniformities will be studied. The results from this project will be useful to assess and predict groundwater contaminant migration and to understand the mineralization of calcite formation in the geochemical environment. 研究期間：9608 ~ 9707
