Effect of partial drainage on plate anchor capacity in sand

The problem of partial drainage is a roadblock that prevents us from safely building offshore floating renewable energy devices. This project aims to better understand how partial drainage impacts the plate anchors that hold these offshore constructs in place.

The goals of this project are to:

1. Develop and implement a coupled finite element model that evaluates the partial drainage effects on plate anchors in sand.
2. Perform numerical parametric studies to understand the various influences on plate anchor response.
3. Perform an experimental study of partially-drained plate anchor pull-out tests to validate our numerical results.

The details

Offshore floating renewable energy devices, such as wind turbines, have become more widespread in recent times. In order to moor these devices securely into the seabed, a suitable anchor is needed. However, we have yet to find a viable cost-effective anchor solution. Plate anchors appear to be a promising answer, but we still need a better understanding of how they perform under a variety of offshore conditions.

In particular, severe storms can impose rapid loading rates upon the anchors, which results in partial drainage. Partial drainage occurs when the water in the porous sand skeleton is unable to drain away upon loading, resulting in a rapid increase of pore water pressure. The reduced drainage has a significant effect on the seabed sand strength, which in turn affects the capacity of plate anchors. It is important that we understand and learn how to mitigate the effects of partial drainage so that plate anchors can be implemented safely and effectively. This project thus aims to investigate the effect of partial drainage on plate anchor capacity in sand using numerical and experimental approaches.

Graduate researcher profile: Zhenyu Liu

What did you do before you started your PhD?

I completed my bachelors and masters studies at Zhejiang University in China before I commenced my PhD. I investigated the characteristics of local scour and breaking waves around a monopile foundation of offshore wind turbines during this period.

What are the challenges of your research role?

I think the biggest challenges in my current role relates to the project itself. Developing an appropriate coupled numerical model is very challenging since there has been limited numerical capability in simulating the capacity of plate anchors under partially drained conditions until now. Conducting physical experiments that are capable of replicating extreme real-world environmental conditions is also quite difficult.

What is the best part of your research role?

In my opinion, the best part of my research role is the opportunity to closely collaborate with the research teams from both the University of Melbourne and the University of Toronto.

Where do you wish to go after your PhD? Do you want to enter industry or continue doing more research?

I would like to continue doing more research after my PhD. There are still a considerable number of problems to be investigated in this field, and I wish to continue my learning in the hopes of solving these problems.

Supervision team

The University of Melbourne: Dr Shiao Huey Chow, A/Prof Yinghui Tian

The University of Toronto: A/Prof Mason Ghafghazi