Investigation of destructive effects of flood flow over slab-on-ground of spillway (Case study: Bukan Dam spillway)

Document Type : Research Paper


1 Ph. D. Student, Faculty of Civil Engineering, Sahand University of technology, Tabriz, Iran.

2 Associate Professor, Faculty of Civil Engineering, Sahand University of technology, Tabriz, Iran.

3 Assistant Professor, Faculty of Civil Engineering, Sahand University of technology, Tabriz, Iran.


When the dam reservoir exceeds its capacity, the spillway, as one of the most significant water-dependent elements of dams, safely conveys the oncoming flood flow to the dam reservoir. Dam safety is inextricably linked to sufficient spillway capacity. Therefore, one of the most pressing issues in all dams is ensuring the accuracy of structures and the hydraulic operation of spillways. In the present study, the hydraulic parameters of the flow on the spillway for the flood discharges with 50 and 10,000-year return periods were simulated using WS77 and Flow3D softwares in order to evaluate the factors affecting the destruction of the concrete panel of the Bukan Dam spillway. Various known factors in the destruction of spillway floor concrete panels such as cavitation, pressure fluctuations, uplift pressure and hydraulic jacks were also investigated. As shown in the results, the minimum cavitation index in selected floods of 50 and 10 thousand years is 0.31 and 0.275, respectively, which is more than the critical value of 0.2. Furthermore, at the maximum values estimated in the two floods, the failure potential index is 111 and 198 (2.5 cm offset) respectively, which is much below the value of the destruction threshold of 500. However, the results show that increased pressure owing to the hydraulic jack phenomenon, as well as uplift pressure to values greater than the concrete panel weight component and anchor strength, has resulted in spillway floor concrete panel displacement.


Main Subjects

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