Non-Darcian flow has been well documented for fractured media,while the potential non-Darcian flow and its driven factors in field-scale discrete fracture networks(DFNs)remain obscure.This study conducts Monte Carlo simulations of water flow through DFNs to identify non-Darcian flow and non-Fickian pressure propagation in field-scale DFNs,by adjusting fracture density,matrix hydraulic conductivity,and the general hydraulic gradient.Numerical simulations and analyses show that interactions of the fracture architecture with the hydraulic gradient affect non-Darcian flow in DFNs,by generating and adjusting complex pathways for water.The fracture density affects significantly the propagation of hydraulic head/pressure in the DFN,likely due to fracture connectivity and flow channeling.The non-Darcian flow pattern may not be directly correlated to the non-Fickian pressure propagation process in the regional-scale DFNs,because they refer to different states of water flow and their controlling factors may not be the same.Findings of this study improve our understanding of the nature of flow in DFNs.
Bingqing Lu Yong Zhang Yuan Xia Donald M.Reeves Hongguang Sun Dongbao Zhou Chunmiao Zheng
Department of Geological Sciences,University of Alabama,Tuscaloosa,Alabama,USA Colllege of Environmental Science and Engineering,Guilin University of Technology,Guilin,China Department of Geological and Environmental Sciences,Western Michigan University,Kalamazoo,Michigan,U College of Mechanics and Materials,Hohai University,Nanjing,China School of Environmental Science & Engineering,Southern University of Sciences and Technology,Shenzhe