FIELD SURVEY OF WAVE-INDUCED PRESSURE FLUCTUATIONS IN THE SANDBAR LAYERS

Abstract

 In this study, pore water pressure in the coastal sandbar layers was measured alongside waves and sandbar profile changes to explore the correlation between sandbar profile change and fluctuation in pore water pressure. In this analysis, negligible changes in sandbar profiles were compared with erosion phases, and accretion phases. The results indicate that pore water pressure fluctuations in the sandbar decayed more rapidly with increasing depth during erosion and accretion phases compared to the phases with almost negligible change. Additionally, a comparison between the vertical pressure gradient and wave steepness revealed that the pressure gradient tended to fluctuate significantly when wave steepness ranged between 0.02 to 0.04 during erosion and accretion phases. During erosion and accretion phases, the fluctuations in the vertical pressure gradient were dominated by upward pressure propagation, suggesting a possible loosening of compaction within the sand layer.