Wave-induced seepage force on a buried pipe in the presence of a floating structure

Abstract

This work aims to understand the variations in the oscillatory seepage force on a buried pipe in the presence of a floating structure under the influence of long-crested waves. The study is based on numerical investigation carried out using Finite Element Analysis wherein the water wave is modelled using potential flow theory and the soil modelling in accordance with Biot’s consolidation equations. The investigation is carried out in the frequency domain considering a range of wave, soil and floating body parameters. At first, the sensitivity of wave and soil parameters on the development of vertical seepage force on a buried pipe is studied. Then a floating body is introduced to the fluid domain and the wave scattering effects on the seabed pressures and seepage forces on the buried pipe are investigated. The numerical results reveal that in the case of barge or floating-fixed breakwater, the increase in vertical seepage forces on the buried pipe is about two-fold in intermediate water depths (π/8 < kh < π/2). The increase in the susceptibility to instantaneous and residual liquefaction of soil above the buried pipe due to the presence of a floating body is also addressed.