Author(s): J. R. Yang; S. J. Chae; K. M. Kim; S. O. Lee
Linked Author(s):
Keywords: Component; Levee breach; Discharge to lowland; HEC-RAS; EAP
Abstract: Recently, we have figured out that the failure probability of hydraulic structures is increased because of incidence of abnormal climate and extreme floods. Discharge into lowland due to levee breach should be the most critical parameter to design and estimate of damage due to levee breach. To estimate of breach discharge into lowland, approaches with hydraulic model experiments have been considered in general. It has advantage to observed visually but it is needed to spend much time, cost and man-power and request the scale effect when it is analyzed. Thus, most hydraulic projects were initially design with aid of numerical method. For example, dam breaks have been applied with one-dimensional analysis (Xiong, 2011). In this study, one-dimensional analysis using USACE Hydrologic Engineering Center’s River Analysis System (HEC-RAS) was applied to calculated discharge into lowland due to levee breach. As the first step, to verify of one-dimensional analysis, both geometric specification of numerical model and hydraulic experiment built to be indentical with each other. Waterway in an experiment is length of 16 m, width of 1.2 m and the center part of levee as movable section was constructed with non-cohesive sediment set up which was length of 4 m, height of 0.3 m, slope of1:2 (V: H) while upstream and downstream parts of levee were built with concrete materials. In order to reproduce the levee breach in numerical simulation, lateral-gate parallel with flow direction was employed. Lateral-gates which can be opened vertically according to water surface level of main stream were arranged following the flow direction in movable levee section. Each gate is opened separately in breached section measured in hydraulic model experiments. It has been reproduced temporal shapes of collapsed levee during collapsed time. Total 5 cases of levee breach experiments were verified. The results show that breach discharge into lowland and water surface level of main stream arealmost identical to those of hydraulic model experiments. According to results from this study, one-dimensional analysis is capable to utilize for prediction of damage by levee breach over time. Also it would be useful to build the Emergency Action Plan (EAP) for levee breach in the design stage.
Year: 2014