Parallel groundwater flow simulation method based on a discrete fracture network model

Objective Groundwater flow in fractured rocks has strong heterogeneity and anisotropy. The discrete fracture network (DFN) method has been internationally considered as one of the most reasonable and effective methods to describe the fracture water transport. Methods In this work, we focused on granite rock from an underground research laboratory site for the geological disposal of high-level radioactive waste. In addition, a high-performance numerical computing system and parallel codes were employed to develop a groundwater flow simulation method in fractured rocks based on the DFN model. Results The results indicated that the proposed method could conduct the groundwater flow simulation of DFN with thousands of mesh elements. This improved the computational efficiency and ability of the parallel codes to deal with complex models. We established the DFN model structure optimization and parameter setting methods of boundary conditions in a complex condition. This could ensure that the hydraulic heads were continuous at different scale models. Furthermore, in the model area, the hydraulic head is distributed as a network structure along fractures. For the connected fractures, the water level was continuous and changed from high to low. However, the water level in the nonconnected fractures was discontinuous. Groundwater flows along the fracture from the high water level area to the low water level area. The connectivity and permeability of the fracture network have an obvious influence on the groundwater flow characteristics. Conclusion Therefore, we could conclude that the parallel groundwater flow simulation method based on the DFN model could more reasonably reflect the groundwater flow in a fractured rock mass. It was of great significance to further improve the simulated prediction ability and deepen the understanding of groundwater flow characteristics in a fractured medium.