GBM Works has developed a technique to get monopiles into the seabed in a silent and fast way.
The vibratory hammer with a jet gun is not only cheaper and less harmful to marine life, the process is also kept under control from all sides. After successful tests on land, founder Ben Arntz is now preparing to put it to the test with an impressive consortium on the water this autumn.
A vibratory hammer that shakes off the ground for the first time in Germany this year with monopiles of more than 1000 tons, will probably be just below 160 Db. Therefore, no additional measures are required, even if that is close to the limit.
The combination of a pick-up hammer and a jet gun. The seawater is sprayed at the bottom of the inside of the monopile. This causes the sand or clay to become liquid, creating a kind of quicksand, which temporarily reduces friction. At the same time, the monopile is driven into the ground with the pick-up hammer. Once the monopile has been installed, the soil in the interior sinks back into place.
The ground remains untouched on the outside. That is crucial. It is the carrying capacity of the ground on the outside that has to withstand the horizontal forces of wind and current on the wind turbine. It depends on the composition of the soil how high the water pressure must be and how strong the vibrations to get the monopile to depth. That is why the entire process is monitored with countless (pressure) sensors.
This method is 3-5 times faster than conventional pile driving. Apart from the time savings, because noise-reducing measures are not necessary. Installation requires much less power and offers more certainty that the monopile will reach the correct depth.