Centrifugal Model Study of Seepage and Seismic Behavior in a Homogeneous Reservoir Dam with Parapet

Abstract

This study examines the effectiveness of parapets in preventing overtopping failures of small-scale homogeneous reservoir dams under seismic loads. In this study, a parapet covered the entire width of the dam crest and was designed to ensure its weight is transmitted to the dam crest. The test included four modes: initial mode, first seepage, seismic, and second seepage. The results show that without parapets the crack length and width expand significantly in the dam crest during the seismic mode, and the effect was large in the second seepage mode. The crack depth increased by 11.3–24 times during the seismic mode and expanded up to 73.3% of the dam height in the longitudinal direction along the axis of the crack formed in the dam crest during the second seepage mode. These findings suggest that the earthquake weakened the dam body, making it vulnerable to penetration. In contrast, the parapet structure effectively suppressed most of the tensile cracks by increasing the constraint force. Additionally, no crack expansion or tearing occurred during the second seepage mode post-earthquake, indicating improved seismic performance and suppression of seepage deformation.

Experimental and Seepage Analysis of Gabion Retaining Wall Structure for Preventing Overtopping in Reservoir Dams

“…In contrast, when anticipating an increase in water level due to heavy rainfall, it is crucial to consider the potential for water leakage at the boundary between the structure and the dam crest in terms of overtopping height and resistance. Previous research findings on the parapet model, specifically designed for preventing dam overtopping, indicate that the design is restricted to a range of 0.5-1 m owing to the risk of water leakage at the dam crest interface [10].…”

“…The historical context, including the agricultural infrastructure focus of the Japanese colonial period and the Korean War, promoted the economical and rapid construction of earthen dams [9]. Most of these dams were constructed to low design standards in the 1900s, without considering their service life [10]. In 2020, 22 reservoirs failed during the rainy season, and the primary failure factor was age.…”

“…This approach is designed to alleviate water pressure within the dam body through the structure's own weight and the To mitigate the risks associated with overtopping, several different slope protection methods have been used on downstream slopes, including ripraps, gabions, vegetative cover, roller-compacted concrete, and biopolymers [19][20][21]. In some cases, the dam crest is constructed with a parapet and a flat concrete foundation for support [10,22].…”

Seepage and Stability Analysis of Earth Dams’ Downstream Slopes, Considering Hysteresis in Soil–Water Characteristic Curves under Reservoir Water Level Fluctuations

“…Over the last several decades, dam slope stability has been studied using a centrifuge, an approach that revealed the mechanism of dam slope failure with water level fluctuations [34][35][36]. It was found that fluctuations in reservoir water levels lead to changes in the PWP and the matric suction in the dam body, reducing the effective stress there; this is unfavorable to the Fs of the dam slope [37]. With the help of modern data transmission technology, dam slopes have been widely studied using field monitoring, which has yielded many useful results [38,39].…”