Seite - 1501 - in Book of Full Papers - Symposium Hydro Engineering

Ph.D. Dissertation. Laboratory of Hydraulic Constructions. Ecole Polytechnique Federale de Lausanne, Switzerland. [13] Umumararungu, M.G. (2016). Physical modeling investigation of rock scour extent due to a plunging jet for typical high head dams. M.S. Thesis. Stellenbosch University, South Africa. [14] Pells, S. (2016). Erosion of rock in spillways. Ph.D. Dissertation. Univ. of New South Wales, Australia. [15] George, M.F. and Sitar, N. (2016). 3D block erodibility: Dynamics of rock- water interaction in rock scour. Report No. UCB-GT/16/01, Dept. of Civil and Environmental Engineering, Univ. of California – Berkeley, USA. [16] George, M.F. (2015). 3D block erodibility: Dynamics of rock-water interaction in rock scour. Ph.D. Dissertation. Univ. of California - Berkeley, USA. [17] Mauldon, M. (1990). Probability aspects of the removability and rotatability of tetrahedral blocks. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 27(4): 303-307. [18] Brown, D. (2016). Tracker Video Analysis and Modeling Tool v4.9.5. physlets.org/tracker/. [19] Goodman, R.E. and Shi, G. (1985). Block theory and its application to rock engineering, Englewood Cliffs, NJ, Prentice Hall. [20] George, M.F. and Sitar, N. (2017). Real-time capture of rock block erosion: Field measurements of hydrodynamic pressure and block displacement in an unlined rock spillway channel. In preparation. SUMMARY Scour of rock foundations and spillways during normal and extreme flood events poses an important concern for dam safety. The challenge of making direct observations during a spill event has limited the understanding of the mechanisms driving the break-up of the rock mass when subject to hydrodynamic loading. Historically, methods for scour prediction have been derived from scaled laboratory studies often using simplified rock geometries and flow hydraulics. We present real-time observations of block removal captured using an instrumented block during a flood event in an unlined rock spillway of a dam in northern California. Particle image velocimetry (PIV) from digital video footage provides information on flow characteristics near the time of removal, while pressure and displacement sensors installed on the block faces provide measurements of hydrodynamic loads and block displacement leading up to failure/removal. 1501