22 / 2025-04-24 11:27:22

Feedback on innovative techniques in digital rock scour

Rock scour downstream of high-head dams and in unlined channels and stilling basins of dam
spillways is a more and more frequently occurring phenomenon. Climate change and related
regulatory requirements generate more frequent functioning of dam spillways, and sometimes
triggers a first main spillage of spillways that have been constructed decades ago but were never
used, or only used for minor discharges. Hence, unlined rock masses downstream of those
structures experience greater hydraulic stress by action of hydrodynamic pressures at the water
rock interface. Sound prediction of incidences involving rock scour during such flood events thus
is becoming more pertinent and necessary, especially for cases where the scour hole may
potentially regress towards the dam or spillway foundations.
This paper firstly presents the background and main principles and methods of rocsc@r, an
innovative cloud-based digital platform to compute scour of unprotected bedrock downstream of
high-head dams and in unlined plunge pools and spillways. Second, the paper presents the
application of this novel cloud-based digital platform to different situations of rock scour at
hydraulic structures.
A first case concerns the 3D numerical reproduction of observed scour after a major flood event
at unlined bedrock downstream of the main spillway of an existing dam. Another application
proposes 3D scour potential for a dam containing a bottom outlet with downstream lining and
baffle blocks, together with a crest spillway and bridge piers in the downstream bedrock of the
river channel.
For these cases, well-known computational methods are compared, such as Erodibility Index
Method and Comprehensive Fracture Mechanics Method, and the latest advances and
innovations in fluid-solid coupling techniques and related 2D and 3D graphical outputs are
presented.