The forces on small diameter piles in wave-current field

In the construction process of building great bridge, steel pipe pile is often damaged by wave force. The research on the dynamic response of pile in wave-current field is attractive for practicing engineers. Base on indoor model test, the forces on small diameter piles in the wave-current field were studied in this paper. The model test was carried into execution aiming at the longitudinal force and the transverse force of pile under varieties of wave-current combinations. In order to compare the wave current forces on piles, single pile and double piles which were designed to tandem and juxtaposition were researched respectively. The longitudinal force and the transverse force of the single pile and the pile group under varieties of wave-current combinations were obtained by the two-component balance. Finally, the variation of the drag force coefficient C_D and inertia force coefficient C_M in Morison equation with the KC number is studied. The influences of the layout of the piles to the wave forces acting on the specific pile, as well as to the flow field are discussed. The research results indicate that there is a close relationship between the forces of the pile in pile group and the spacing diameter ratio. In addition, the test results reveal that the transverse force has more randomness, and its peak value can be approach the longitudinal force. The result of research can provide references for practical project and further study.