Author(s): U. Helbig; H. -B. Horlacher; J. Stamm
Linked Author(s): Jürgen Stamm, Ulf Helbig
Keywords: No Keywords
Abstract: Several damages particularly caused by hydroabrasion on hydraulic concrete structures are frequently detected and described in the technical literature. It is obvious that the hydroabrasion process of concrete surfaces causes intense demolition and leads to an increase of the hydraulic roughness. Thus flowing waters possess variable parameters concerning flow velocities, mixtures of sediment and resulting bed loads. This context has to be attended both in designing of hydraulic structure’s surface and in experimental or numerical replication. Computations of the hydroabrasive erosion on surfaces of hydraulic structures subjected to extreme flow velocities are not practiced yet. A semi-empirical predicting method that allows to approximate the value of the wear of new intact concrete under a hydroabrasive regime has been developed by HELBIG/HORLACHER on the basis of BANIA’s established correlation between compressive strength, stress-time factor and the impacting kinetic energy. The angle of incidence, the flow velocity and the resulting transport of solids present a relevant role. Furthermore, since August 2009 a 24-month research project funded by the German Research Foundation has been realised in cooperation with the Institute of Materials (TU Dresden) to clarify and to explain the coherences between the concrete’s macroscopic hydroabrasion behaviour and the microscopic crack formation. These facts are essential for predicting the abrasion resistance, for designing the hydraulic structure or estimating the structure’s remaining service life. The results of the experiments should generate a basis to develope a numerical hydroabrasion model based on the Distinct-Element-Method (DEM) and for upgrading the semianalytical prediction method.
Year: 2010