裂隙為裂隙岩層中溶質傳輸的主要流徑，為了解析裂隙岩層中有害廢棄物濃度團的傳輸行為，了解岩層中的流場狀況是很重要的議題。然而，目前有關裂隙岩層中的化學船輸研究卻付之闕如。本研究提出模擬裂隙岩層中化學傳輸的技術，並選用 Discrete fracture network (DFN) 模擬裂隙岩層中的各個裂隙並藉以獲得岩層中的詳細地下水流場狀況。本研究選用Fracman結合裂隙相關參數(如位態、尺寸與間隙)產生三維裂隙含水層，並結合質點傳輸particle tracking (PT)、化學反應以進行四氯乙烯Tetrachloroethylene (PCE)傳輸與降解模擬。本研究首先考慮僅有三個裂隙的簡易裂隙含水層進行該技術的測試與驗證，接著再利用裂隙場址所獲得的相關參數進行現地複雜裂隙研究，最後再考慮現地井注入汙染團至複雜裂隙含水層以研究污染團之移動與降解狀況。簡易裂隙含水層之模擬結果顯示本技術能獲得良好成果，而複雜裂隙與單井注入情境則表明本技術能在現地複雜狀況下獲得PCE之詳細傳輸與降解情況。本研究所提供之技術預期將能為裂隙含水層中水流移動、污染團傳輸與降解之模擬與預測，以及後續之應變與處理提供一良好工具進行相關之後續研究。;Fractures are major flow paths for solute transport in fractured rocks. Understanding the flow field in fractured rock is necessary to trace the transport of concentration plume including disposal of hazardous waste. However, reactive transport study with the detailed geometry of fracture is limited. Discrete fracture network (DFN) shows advantageous capability in representation natural fracture system because of its ability to explicitly model the individual fractures, moreover it allows us to obtain the detailed flow pathway of subsurface groundwater movement in fractured rock mass. The study mainly presents the concept of a framework that can simulate reactive transport in porous fractured media. The new technique coupled particle tracking (PT) and chemical reaction model is developed to simulate Tetrachloroethylene (PCE) degradation and transport in 3D discrete fracture networks. FracMan was employed to generate a stochastic DFN using fracture orientation, fracture size, and fracture intensity; and then particle tracking is performed with a view to obtain flow traces. The extracted particle traces can provide 1D flow paths for PHREEQC code to model reactive transport in complex fractured rocks. The study first uses a simple fracture system with three single fractures to evaluate and test the workflow with the new coupling FracMan & PHREEQC and develop the new module. Secondary, complex fracture network system with four realistic fracture sets obtained at a selected site is then simulated to implement the framework in order to model the reaction and transport of PCE in 3D DFN and the last case is point source injection modeled with a view to demonstrates disposal of hazardous waste issue. The simulation results successfully show PCE reaction process along particle traces in both cases: simple fracture system and complex fracture system. Simple fracture network simulation shows good results for new technique of reactive transport model and also proves the work flow and the new module are correct. The results of complex fracture system simulation reflect the potential capability of this new model applying on complex situation which this new module can handle multi particles for PHREEQC simulation. Regarding disposal of hazardous waste phenomenon, the point source injection of contaminant simulation provides the understanding the fate of contaminant transport of subsurface flow with the specific geometry of fractures. For contaminant treatment problem, the new technique particle tracking – chemical reaction reflects a useful tool for fracture modeling and for predictions of flow and contaminant transport, furthermore, the safety time and distance also can be predicted for contamination treatment.
