Seepage Characteristics of Agricultural Reservoir Embankment Based on Installation of Overtopping Prevention Structures

Abstract

In this study, a structure that can effectively prevent overtopping caused by abnormal rainfall was installed in a deteriorative agricultural reservoir, and seepage characteristics were compared and analyzed through model experiments and numerical analysis. The experimental conditions were observed by installing a stepped gabion, vertical gabion, and parapet in combination with a gabion retaining wall, geomembrane, and core on the dam crest. Small horizontal and vertical displacements without defects were found, such as overturning and failure, to effectively prevent overtopping. A comparison of seepage line and pore water pressure results indicates that the seepage water drained smoothly to the toe drain through the filter from the upstream slope. It was perceived that the concentration of seepage water on the upper part of the dam crest might cause leakage to the upper part of the downstream slope and affect the stability of the overtopping prevention structures. The distribution of the hydraulic gradient was found to be stable in all cases on the downstream slope. The upper part of the downstream slope could be vulnerable to leakage, so careful management is required when constructing the geomembrane. Overall, among the three overtopping prevention structures applied, a stepped gabion retaining wall did not cause such problems as overturning and leakage. Therefore, it is considered better than the other types of overtopping prevention structure.