Interaction of suspended pipelines with sea bottom in deep water applications

Summary. The present study investigates the problem of dynamic interaction of suspended pipelines with sea bottom for deep water marine applications. Effort has been made to calculate the Soil reaction-Pipe Embedment curves and to incorporate the associate results into the numerical code that solves the complete 3D nonlinear dynamic problem of the pipeline under the action of top imposed harmonic excitations. The solution to this problem was achieved by solving the complete system of PDEs that govern the 3D nonlinear dynamics of the pipeline. The mathematical formulation of the problem and the method of the numerical solution are described in detail in (5-6). The actual configuration of the pipeline involves a structural peculiarity associated with the fact that there is a discontinuity between the suspended and the bottom laying part. The discontinuity occurs exactly at the location of the TDP. In order to surpass that problem the proposed solution technique assumes that indeed the geometrical configuration is continuous regardless the occurrence of TDP. Nevertheless in the general case the mechanical and physical properties along the complete length of the pipeline are considered variable. The component that makes the difference is the vertical component of the distributed force, namely the submerged weight per unit length.