Engineers at RMIT University have unveiled a new device to make testing seabed soil for offshore wind farms easier and cheaper.
The RMIT University invention launches a probe into the seabed to provide valuable data on what lies beneath. The testing is normally done by winching or dropping probes, known as penetrometers, from the deck of a support vessel.
Lightweight probes are less effective in penetrating the sandy seabed for wind farm projects in shallower water, and heavy-duty probes can cost up to $200,000 a day.
The RMIT researchers tested their launching device with various probe tips in different sand mixes within a water tank, using an array of sensors and high-speed cameras to capture results.
Results published in the Canadian Geotechnical Journal indicate that the device could be twice as effective in penetrating the seafloor compared to existing lightweight free-fall soil testers, and more cost-effective than heavy-duty probes.
RMIT PhD candidate and study lead author, Junlin Rong, said these results showed the device’s significant potential.
“In laboratory environments, the device showed considerably greater penetration potential compared to free-falling probes on soil. Notably, in high-density sandy material, the penetration depth was twice that of previously reported values achieved by freely falling probes,” Mr Rong said.
“This breakthrough technique has the potential to revolutionise site investigations for wind farm projects, offering significant time and cost savings while outperforming the embedment achieved by other dynamic penetrometers.”
The device is designed with environmental friendliness in mind, as probes can be retrieved and reused after data collection, allowing ‘probe and go’ testing that minimizes disturbance to the seabed.
It can also be adapted to existing probes, allowing engineers to retrofit their current devices with minimal investment.
Mr Rong said that while existing cone penetration testing methods would remain dominant, their launching system could reduce the number of these expensive tests needed, resulting in substantial savings.
RMIT Professor of Geotechnical Engineering, Majid Nazem, said that the device is ready for field trials.
“”Now that our experiments have demonstrated the device’s ability to achieve considerable embedment depth in dense sand, we are keen to conduct field trials and collaborate with our potential industrial partners to further test its performance for offshore geotechnical engineering applications.”
The research was conducted with colleagues at the University of Melbourne in RMIT’s Heavy Structures Laboratory and supported by the Australian Research Council through the Discovery Project scheme.
Featured image: RMIT Professor of Geotechnical Engineering, Majid Nazem, and RMIT PhD candidate and study lead author, Junlin Rong, with the device. Image credit: RMIT.
