Study On Calculation Method And Effectiveness Of Control Of Seepage In Surrounding Rock Masses Of Underground Hydropower Station Openings

Based on the previous research findings in hydraulic engineering, aiming at the seepage problem in surrounding rock masses of underground hydropower station openings, the refined solution to the seepage field with FEM and the design of water-resisting and drainage structures are studied in detail in this paper. The key contents involved are as follows:(1) The key issue in solving seepage problem in surrounding rock masses of underground hydropower station openings is to identify the location of free table. The intensive generation about the methods of solving the free table is presented in this paper by author. The advanced nodal virtual flux method was used to solve the seepage problem with free table and complex geometry boundary conditions. On the basis of theory of saturated-unsaturated seepage, the numerical model taking into account rainfall infiltration was proposed, in which the treatment methods of boundary conditions are solved perfectly.(2) It is difficult to simulate the drainage curtain consisted of densely distributed numerous drainage holes, which is key point in design of seepage control measures. Drainage holes (curtains) must be simulated exactly to obtain the refined solution to the seepage field, which requires high technique demands for mesh generation and capacity of computer.The question is extremely complicated.On based of original drainage substructure put forward by WANG Lei, the author has overcome its shortage by adopting the technique of improved drainage substructure which is very rigorous in theory proposed by Pro.ZHU Yueming. So the simulation of the whole 3-D seepage behavior and effectiveness of seepage control become true.(3)At present the research findings proposed in this paper has been successfully applied to the technique design of Pingtou underground plant.