Study on the Bearing Capacity of PVC Suction Caisson for Marine Aquaculture Cage under Monotonic Inclined Loading
DOI:
https://doi.org/10.65904/3083-3590.2026.02.08Keywords:
PVC suction caisson, inclined pull-out capacity, motion behaviors, structural strengthAbstract
As marine aquaculture cages are increasingly deployed in deeper waters, conventional foundation solutions are confronted with growing challenges associated with high installation and maintenance costs. This study proposes a corrosion‑resistant, lightweight, high‑strength, and low‑cost PVC-made suction caisson for floating marine aquaculture cages in deep waters. A series of model tests were conducted to investigate the monotonic inclined bearing behavior of PVC suction caissons in sand, considering the influences of the aspect ratio and loading angle on the inclined bearing capacity and failure modes. The optimal loading angle is around 16° and the optimal suction caisson aspect is approximately 2.0, offering the highest bearing capacity at relatively small displacements. As the aspect ratio decreases or the loading angle increases, the motion behavior shifts from rotational failure to vertical pull‑out failure. In addition, the PVC material exhibits a high safety margin in caisson wall strength around the loading point. Results also show that under the same inclined bearing capacity, the PVC suction caisson is the most cost-effective foundation type compared with the steel-made suction caisson and the gravity-base foundation. The application of PVC suction caissons in deep waters for marine aquaculture cages mooring systems exhibits sufficient reliability and promising prospects.
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