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In order to study the percolation and dam slope’s stability of an impermeable wall composed by clay and concrete for earth-rock dam, the steady seepage field of a reservoir in Jiangxi is numerically simulated by using finite element method based on the basic principles of saturated and unsaturated seepage under different ratios of clay to concrete. The results of the flow field of steady seepage are carried out and the dam slope’s stability is analyzed. We found relatively minor impacts of concrete proportion on the discharge of seepage per unit width and the dam slope’s stability. In this study, the impermeability performance of the impermeable wall is concerned. The results showed that impermeable effect of the impermeable wall has not obviously changed if the concrete proportion is below 0.43. When the proportion of concrete exceeds 0.43, the anti-seepage effect of the impermeable wall begins to change significantly. Besides, when the proportion of concrete reaches 1.0, the reduction of water level at front and behind impermeable wall, the discharge of seepage per unit width, and the safety factor of the Bishop method are all infinitely close to the value of the best anti-seepage performance and the most stable state of the dam slope.

Based on the governing equations of steady incompressible fluid, renormalization group (RNG) turbulence model and SIMPLEC algorithm are used to calculate the steady flow field of regulating tank in the pumping station with six different geometries operating under same condition. The impacts of the layout schemes of guide walls for the flow field of the regulating tank are analyzed. The numerical results are verified by physical model experiment and good agreement is found. The results show that: 1) serious flow separation of side wall will occur in the regulating tank when the interval of diversion wall is 10 L; 2) the flow velocity in the regulating tank will be too low when the diversion wall spacing is 16 L; 3) the improvement of the flow pattern of the regulating tank is not obvious; and the project cost is increased when the excavation depth of the regulating tank is increased by 1 m; 4) the bottom velocity reached the non-silting velocity and the head loss of the regulating tank reducing nearly 1.2 m by using arrangement form of wide 21 L and narrow 10L of the guide walls, which provides a certain guarantee for the safe operation of the pumping station. The regulation tank layout scheme proposed in the paper can be applied to engineering practice.