Three-Dimensional Simulation of Subsurface Flow Dynamics in Karst Conduits at the Jingxian Pumped Storage Hydropower Plant

Three-dimensional numerical simulation of subsurface flow dynamics in karst conduits at dam sites represents a pivotal component of hydrogeological research, essential for unraveling the intricate behavior of water movement within karstified terrains. This study introduces a novel approach for accounting for the presence of karst conduits and presents a comprehensive three-dimensional flow simulation for the dam site of the Jingxian Pumped Storage Hydropower Plant. This method reduces mesh division, simplifies calculations, and improves model convergence. The findings reveal that the numerical model adeptly captures the declining groundwater levels within the study area, with enhanced precision achieved through the utilization of COMSOL’s Line Mass Source feature. By representing leakage tunnel cylinders as edges, the model significantly improves meshing efficiency, circumventing the computational burden associated with the explicit resolution of intricate geometric details. In the absence of remedial measures, the simulation predicts that groundwater will preferentially drain downstream via two distinct leakage pathways at the dam’s base, presenting a potential threat to the structural integrity and operational stability of the project. To address this risk, the implementation of robust seepage control measures is imperative. Once these measures are established, the dam is expected to function as an effective hydraulic barrier, ensuring the long-term stability and operational efficacy of the hydropower plant.