K(A)RAHNJ(U)KAR DAM SPILLWAY: OPTIMIZATION BY HYDRAULIC MODEL TESTS
The Kárahnjúkar HPP in Eastern Iceland was completed in 2008. Three dams store a reservoir with a life volume of 2100million m3 water harnessing several glacier rivers. An unregulated spillway conveying floods from the reservoir into the river bed is located at the left embankment of the 198 m high main dam. This facility was designed for a discharge of 1350 m3/s and evacuates a PMF of 2250 m3/s. It consists of a side channel, a transition bend and a 419 m long chute.At the chute end, the water falls as a free jet into a narrow canyon with almost 100 m high rock flanks. These flanks are unstable due to cracks and soft rock. The Laboratory of Hydraulics, Hydrology and Glaciology (VAW) of ETH Zurich was commissioned to conduct the hydraulic model tests of the spillway. Two aspects had to be considered as the main challenges: (1) The jet was not allowed to touch the canyon flanks, and (2) A minimum energy density had to be generated at its impact onto the river bed. A detailed optimization process was necessary to achieve these two goals. The lower chute section was found as the critical component in this regard. A novel chute takeoff structure including a step for small discharges was finally proposed. This paper highlights the design challenges of an unregulated spillway combined with a narrow canyon and describes the resulting structure focusing the unusual configuration along the lower chute part.
chute jet karahnjukar scour spillway
Michael Pfister Thomas Berchtold Adriano Lais
VAW, ETH Zurich, CH-8092 Zurich, Switzerland
国际会议
第16届亚太地区国际水利学大会暨第3届水工水力学国际研讨会(16th IAHR-APD Congress and 3rd Symoposium of IAHR-ISHS)
南京
英文
2106-2111
2008-10-20（万方平台首次上网日期，不代表论文的发表时间）