Seepage and Piping Control of Earth Fill Dam

Abstract

The Pidekso Dam is one of the major dams in the Central Java, situated in Wonogiri Indonesia. The stability analysis of the dam is required due to this dam is planned for national water and food security program covering the irrigation area of $15 \times 10^6 \,{\text{m}}^2$, increasing the planting intensity from $20 \times 10^6\,{\text{m}}^2$ to $36 \times 10^6 \,{\text{m}}^2$ and as a source of water around 300 L/s for Wonogiri, Sukoharjo, Solo and their surroundings. The control is needed for the safety of the dam from seepage and piping. Excessive seepage can cause piping and lead to dam failure. Seepage control is carried out by 3 alternatives, extended curtain grouting, cut off wall and upstream blanket respectively. Each alternative is divided into 4 models: (1) original length (L), (2) 2/3L, (3) 1/3L and (4) 2/3L with doubles in the upstream and downstream of the dam. The result indicates that, the installation curtain grouting with model 1 is the most effective alternative to reduce seepage up to 67.82% of dams.