Seepage Behavior of Earth Dams Considering Rainfall Effects

Abstract

More than 60% of annual rainfall in Korea is concentrated during the monsoon season from June to August because of the climate characteristics of East Asia. In general, reservoir water levels sharply rise during this period and rock-fill dams are exposed to various types of damages such as soil erosion and piping related to seepage problems. However, the detection of seepage problems is generally more difficult because rainfall directly flows into a V-notch weir according to a downstream shell in which seepage rates can be measured downstream. In this paper, rainfall is filtered out from the measured seepage rates to evaluate the effects of rainfall by using a digital filtering method for two large rock-fill dams (Dams A and B). Seepage behavior for these two large rockfill dams was estimated as a steady-state condition. It has been proven that with the application of a digital filter which filters out rainfall-induced infiltration into a downstream shell from a measured seepage flow would make analyzing the seepage behavior of dams more effective. is also shows that consideration for any rainfall effect on the seepage behavior of earth dams is very important. e seepage rate of Dam A was not significantly affected by rainfall because the seepage water was collected inside the dam body and was transferred to a V-notch weir located downstream from the dam through a steel pipe. On the contrary, the seepage rate of Dam B was greatly influenced by rainfall in the rainy season. Also, the permeability of the core zones for Dams A and B was estimated at 8.5 × 10 −5 cm/sec and 2.7 × 10 −5 cm/sec, respectively, by a simplified method.

Slope stability analysis of a dam. Case study: Hălceni Reservoir, Iasi county, Romania

“…Maximum water level of steady seepage case was considered to evaluate seepage (Malik and Karim, 2020). The seepage flow through the core zones of the dam was found to be correlated with the reservoir water levels (Lee et al, 2018).…”

Research on the infiltrations in an earth dam. Case study: Cuibul Vulturilor Reservoir, Vaslui County, Romania

“…Abnormal seepage problems, such as piping in the core zone of the dam, can be detected by carefully analyzing the relationship between the reservoir water level and the seepage rate. The seepage rate through a dam should be measured and used as a basis of a seepage stability evaluation [7].…”

Reduction of Seepage Risks by Investigation into Different Lengths and Positions for Cutoff Wall and Horizontal Drainage (Case Study: Sattarkhan Dam)

“…Seepage control methods should reduce the amount of water seepage and minimize the risk of damage from slope instability, washout, or scouring of rened grains [4]. e following are methods for reducing seepage in the body and foundation of an earth dam: (a) use of the core with very low permeability in the dam body; (b) use of the blanket on the upstream surface; (c) use of the cuto wall in the dam foundation; (d) use of the grout curtain in the foundation; and (e) use of a layer with very low permeability at the bottom of the reservoir [5,6]. Due to economic factors, cuto walls are currently trendy.…”