Abstract
Seepage under hydraulic structures, such as dams, is considered one of the most important problems that lead to the collapse of dams, especially if these structures are in areas active by earthquakes. Therefore, sheet piles are used under dams to reduce seepage. Due to the recent increase in activity of earthquakes, a study the behavior of dams exposed to earthquakes is necessary and important.
In this study, a laboratory study was conducted to determine the effect of earthquakes on the sheet piles under a concrete dam. A concrete dam model was used with dimensions of length = 49 cm, width = 15 cm, and height = 20 cm, with sheet piles of length = 15 cm, in different locations under the concrete dam and on sandy soil and exposed to different earthquakes (Halabja, El-Centro, and Kobe).
The results showed that the pore water pressure is reduced by 25% for the Halabja earthquakes, 42% for the El-Centro earthquakes, and 47% for the Kobe earthquake in the case of using sheet piles at the upstream and downstream sides, while in the case of using sheet pile wall at the upstream, the pore water pressure is reduced by 41% for the Halabja earthquake, 65% for the El-Centro earthquake, and 69% for the Kobe earthquake.
Also, the results indicate that the vertical displacement in the case of using the sheet pile under dam at the upstream and downstream sides reaches 0.091 mm by when dam subjected to Halabja earthquake, 0.05 mm to the El-Centro earthquake, and 1.02 mm to Kobe earthquake, while in the case of using the sheet pile at the upstream side, the vertical displacement reaches 0.025 mm for the Halabja earthquake, 0.17 mm for the El-Centro earthquake, and 1.2 mm for the Kobe earthquake.
It was found when measuring the seepage under the dam that the flow increased after the earthquake for all cases, where the increase in the case of not using sheet piles under the dam reached 15% for the Halabja earthquake, 87% for the El-Centro earthquake, and 275% for the Kobe earthquake, while the increase in seepage is reduced in the cases of using sheet piles. In the case of using sheet piles on the upstream side, the increase was 5% due to the Halabja earthquake, 54% due to the El-Centro earthquake, and 258% due to the Kobe earthquake.
