Optimization analysis of seepage control design in Mopanshan Reservoir, northeastern China

Abstract

Anti-seepage calculation is key to the design of reservoir dams, and the uncertainty parameter makes the sensitivity analysis a useful tool in the design process. A reservoir constructed in northeastern China was selected to analyze optimal anti-seepage designs, and numerical models have been established with visual MODflow software. The results of analyzing seepage field characteristics show that under different schemes, anti-seepage capability is controlled by the length of an anti-seepage body on the left riverbank and the depth of curtain grouting, and that seepage decreases with increasing length of the anti-seepage body and depth of the curtain grouting. The results of the sensitivity analysis show that, according to the sensitivity analysis, the permeability coefficient had different effects on the seepage gradient under incomplete and complete anti-seepage. Under incomplete anti-seepage, the seepage increased with permeability coefficient and the seepage gradient increased; and under complete anti-seepage, the seepage increased slightly with the permeability coefficient, and the seepage gradient decreased, the permeability coefficient of the anti-seepage body clearly influences the anti-seepage effects. From a project investment standpoint, complete anti-seepage on the left riverbank with a curtain grouting standard of 5 Lugeon units (Lu) is the preferred anti-seepage control scheme. This scheme not only guarantees the safe operation of the dam but also ensures that seepage is less than the acceptable seepage limit, is close to the natural groundwater flow rate, and that the scheme will not significantly impact the downstream hydrogeological environment after the construction of the dam.