Vol18 No.2: 462-481
【Title】Physical modeling into outflow hydrographs and breach characteristics of homogeneous earthfill dams failure due to overtopping
【Author】KOUZEHGAR Kamran1; HASSANZADEH Yousef1,2,*; ESLAMIAN Saeid1, 3; YOUSEFZADEH FARD Mikaeil1,4; BABAEIAN AMINI Alireza1,5
【Addresses】1 Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad 8514143131, Iran; 2 Department of Water Engineering, Center of Excellence in Hydroinformatics, Faculty of Civil Engineering, University of Tabriz, Tabriz 5166616471, Iran; 3 Department of Water Engineering, Isfahan University of Technology, Isfahan 8415683111, Iran; 4 Faculty of Civil Engineering, University of Tabriz, Tabriz 5166616471, Iran; 5 Faculty of Civil Engineering, University of Bonab, Bonab 5551761167, Iran
【Corresponding author】HASSANZADEH Yousef
【Citation】KouzehgarK, HassanzadehY, EslamianS, et al. (2021) Physical modeling into outflow hydrographs and breach characteristics of homogeneous earthfill dams failure due to overtopping. Journal of Mountain Science 18(2). https://doi.org/10.1007/s11629-020-6177-1
【Abstract】The main objective of the present study is to introduce new empirical equations for the determination of breach geometrical dimensions and peak outflow discharge (Qp). Therefore, a historic failure database of 109 embankments was collected and examined. The most important factors that affect the breach evolution, including grading size, hydraulic, and outflow characteristics are also studied. Some of the parameters used for the determination of Qp and average breach width (Bave) have a significant effect on the erosion process, but they are less reflected in the technical literature. To study the behavior of non-cohesive soils during overtopping, 15 physical tests were performed at the laboratory, and the effects of interfering parameters were investigated.The experimental output hydrograph was used to simulate the hydrographs resulting from the failure of real dams, and recent artificial intelligence techniques along with linear and nonlinear regression models were employed. The area-time analysis of the laboratory hydrographs shows that the soil particle size and the characteristics of reservoir-basin significantly affect the rate of breach formation and outflow discharge. New relationships are introduced, based on the breach characteristics, by a combination of historical and experimental data, as well as case studies conducted on the hypothetical failure of 10 operational dams. The mathematical model is also used to simulate the process of breach evaluation.Based on statistical indices, comparison of the results, and sensitivity analysis, the developed equationscan better express the susceptibility of materials to erosion and their application can minimize downstream vulnerabilities.
【Keywords】Dam breach; Peak outflow; Output hydrograph; Modeling; Soft computing; Experimental setup