He, R.; Zhang, J., and Chen, W., 2017. Using the elastic vertical vibration of a rigid caisson at low frequencies to stabilize the foundation of coastal engineering structures.

A suction caisson or a bucket foundation offers a suitable and economic foundation type for many coastal structures (such as breakwaters and wind turbines). Because of the relative stiffness of a caisson foundation compared with the surrounding soil is high, the caisson is treated as a rigid cylindrical shell in this article. Seawater and seabed are treated as a coupled seawater–seabed half-space. In that way, the elastic, vertical vibration of a caisson can be modeled as the vertical vibration of a rigid shell embedded in a fully saturated, porous seabed. The solution to the problem is obtained with the ring-load Green's function and proper boundary conditions at the caisson–soil interface. With integral equations, the governing equations are transformed to Fredholm equations and are solved numerically. Numerical results show that, for a rigid shell embedded in a homogeneous sandy seabed, the dynamic contact-load transfer mechanisms are similar, and the nondimensional dynamic impedances are almost the same for various kinds of sands. By the obtained dynamic stiffness and damping of the caisson, the dynamic responses of a caisson-supported coastal structure can be obtained easily.