Design and construction of an underwater bund built on dredged material in the Doeldock
Type:
Presented during:
WODCON XVII: "Dredging in a Sensitive Environment" - 2004, Hamburg, Germany
Authors:
Ir. H. De Preter, Ir. S. Vandycke
Abstract: The Doeldock is located on the left bank harbour of the port of Antwerp, it was constructed in thelate 70's early 80's and was predestined for chemical and petrochemical industry. There are no Quay walls,only slopes ideal for chemical carriers to berth at jetties and unload their cargo. However, due to a changingeconomical situation and the changing legislation and environmental constrictions the development of chemicalindustry never took place. The lack of quay walls made it very difficult for any other industry to settle aroundthe Doeldock.
During this time underwater cells were dredged to store dredged spoils from the maintenance dredging on theriver Scheldt that resulted in an unused dock without quay walls with soft dredged material below the bottom.
During the construction of the new Deurganckdock, a tidal dock for container traffic, on the left bank of theRiver Scheldt, a large amount of dredged soil had to be stored and no storage was available. Therefore it wasdecided to fill a large part of the Doeldock with this soil.
In order to limit the negative consequences to the environment a physical separation had to be constructed toseparate the part that will be filled from the part that remains dock.
This paper will describe the design parameters and calculations for the construction of a 25 m high bund (from15 to +10 TAW) on top of an eight-meter thick layer of dredged spoil as well as the special techniques thatwere used for the foundations and the construction of the bund. These techniques include the patented SSITechnique for the foundations and the modification of existing dredging equipment in order to comply with therestrictions of the staged construction on which the design calculations are based.
Keywords: underwater bund, Deep Soil Mixing, spreader pontoon, geotextiles