Penetration behaviors and soil plug developing of the scaled suction caisson during installation

Inspired by the anisotropic shear behavior of the snakeskin, an innovative suction caisson with a bio-scale sidewall of the snakeskin is proposed, which is called the scale suction caisson (SSC). Compared with traditional suction caisson (TSC), the interface friction decreases when the SSC penetrates to the seabed, but increases as the SSC is pulled out. Therefore, the SSC has better installation and service performance than the TSC. The model tests are carried out to investigate the penetration behaviors of the SSC. The study shows the penetration resistance depends on the aspect ratio of the bio-scale surface, and the corresponding value increases with increasing the diameter of bio-snakeskin surface D1, but firstly decreases and then increases with increasing the height of bio-scale surface H1. More sand bypasses the end of the sidewall into the SSC and the sand inside the SSC is loosened under the seepage, causing the soil plug inside the caisson. In the half-caisson model tests, the soil heave inside the caisson under the different penetration depths is captured with an HD camera, and the permeability coefficient k can be further calculated. Considering the variation of the permeability coefficient k, a method of calculating the critical suction is provided. •The suction, penetration resistance, and height of soil plug of the SSC are investigated.•Soil plug developing of the SSC is visualized and captured with an HD camera in the half-caisson model tests.•Considering the variation of the permeability coefficient, a method of calculating the critical suction is proposed.