Pore pressure distribution and momentary liquefaction in vicinity of impermeable slope-type breakwater head

Abstract

In this paper, wave-induced pore pressure distribution and momentary liquefaction of seabed soil around impermeable slope-type breakwater head are investigated. The wave-induced fluid motion is governed by the Reynolds-averaged Navier-Stokes equations and the Biot’s theory for poro-elastic medium is adopted to simulate seabed behaviour. The wave motion and seabed response in vicinity of breakwater head, which have rarely been investigated in the literature, are reported in detail. An iterative calculation scheme is proposed to integrate the wave motion and seabed response. The results reveal that: (i) Wave-induced flow field in the vicinity of breakwater head is significantly disturbed by wave-structure-seabed interaction, leading to wave reflection, diffraction and overtopping; (ii) Seabed response on the seaward side of the breakwater head is more significant than those on the landward side; (iii) Existence of breakwater aggravates the seabed liquefaction at the seaward side of the breakwater, and alleviates the seabed liquefaction at the landward side of the breakwater; (iv) Decreasing breakwater slope could moderate the seabed liquefaction in the vicinity of the breakwater head, and a mild breakwater slope is proposed to be adopted in practice.