Physical experimental study on the formation mechanism of pockmark by aeration

Abstract

As one of the common geological disasters on the seafloor, the occurrence of pockmarks often indicates the existence of submarine fluid. And the formation of the pockmarks is generally attributed to the soil carried away by the fluid. The research established physical model test and found: (1) The pockmark formed after aeration, and particle gradation changed in the center area of the pockmark where coarse particle (particle size/0.25 mm) increased obviously and fine particle (particle size ≤0.075 mm) decreased significantly; (2) Comparing the volume of the pockmark with the volume of the soil extracted by siphon, it can be found that the volume of the pockmark was much larger than the loss of soil, and the difference reached its peak when the inflation pressure was 20 kPa; (3) Comparing the cone resistance of the soil in the surface and boundary, it can be found that the resistance of the center and marginal soil was much bigger than the outside, and the cone resistance of the boundary was also improved greatly. The research considered that the formation of pockmark was not only related to the soil being carried away by the bottom current, but also the consolidation by vibration existed.

Keywords:

• Pockmark
• aeration
• cone tip resistance
• consolidation by vibration
• physical model

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research work was supported by Zhejiang Basic Public Welfare Research (LGF18D020001).