The Radial Expansion of Piping Channel in Double-layer Dike Foundation
Jia Kai, Cao Hong, Li Xing-Hua, Zhao Hui
State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou, Guangdong 510641, P. R. Chinas
The development of piping in double-layer dike foundation involves radial and axial channel expansion, processes in which the sand particles are eroded and then carried away by pressure-driven flows. The expansion process is erosion process during which the flow velocity and the area of the cross-section influent each other and finally reach a dynamic balance. In the framework of mechanical balance of the particles, a new method to judge when the radial channel will expand is proposed. In this method, the randomness of diameters of particles, the positional relation of the particles as well as the influence of water flow to the particle are reflected by the relative exposure degree of the particles, fluctuating velocity, criteria of incipient motion and flow characteristics. The laboratory tests have demonstrated the validity of this method.
Keywords: Piping channel; Sediment incipient motion; Channel expansion; Exposure degree
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