Hydraulic engineering vehicle
Aerial view of "The Palm, Jumeirah" Palm Islands
Hydraulic engineering vehicles include ships that are used to move soil material in a body of water. The tasks of these special ships are varied in nature such as:
- Extraction of building material ( sand and gravel ) for the building industry ;
- Reclamation of soil for land reclamation / coastal protection ;
- Maintenance of bodies of water (e.g. removal of contaminated sediment layers );
- New construction and expansion of waterways and ports ;
- Maintenance of the waterways and ports to restore the depth required for navigation .
The dredged material from dredging is treated differently:
- Either it is removed from the water by flushing on land in flexible or rigid flushing pipes, for the extraction of building materials and land reclamation or the dumping of contaminated sediment for storage and pretreatment;
- in other cases, it is relocated in the water by dumping into areas in which the dredged material is no longer disturbing due to the existing water depth. This method is mostly used where the maintenance of the waterways is necessary for shipping.
There are various types of dredgers for such tasks :
- Pontoon excavators stand on a floating pontoon anchored by stilts or wires . This is either a rope or hydraulic excavator that picks up the dredged material at the bottom of the river and deposits it on land or in barges .
- Bucket chain excavators (elevator excavators ) are anchored by ropes - more rarely on stilts - and have a rotating bucket chain that picks up the dredged material from the ground and transports it in barges.
- Cutter dredgers are mounted on a floating pontoon anchored by stilts or wires. From the front end of the pontoon, a suction pipe with a rotating cutting head protrudes into the water, which picks up the dredged material at the bottom of the river. The dredged material is then washed ashore or in barges.
- Hopper dredgers in the narrower sense (self-propelled loading space suction dredgers ) are self-propelled ships that use a suction pipe to pick up the dredged material at the bottom of the river and pump it into the ship's hold. The water that gets into the hold is drained through an overflow so that only the dredged material remains in the hold. When the loading process is completed, the dredged material is transported to folding points and folded or flushed there.
- Water injection device that is carried by a free-floating ship near the bottom of the water and blows pressurized water into or onto the soil layer through a pressure pipe so that the sediment is flowable and carried away from the dredging area by the natural current.
The above devices include:
- Split hinged barges
- Flushing barges
In Germany, around 40 to 50 million m³ of sediment are dredged to maintain the waterways. Inland waterways maintenance accounts for around 8 million m³ of this.
Buildings that were created with hopper excavators
One of the world's largest construction projects , where hopper excavators are involved in the construction and flushing, is the construction of Palm Islands . Also, the Hong Kong International Airport has been flushed through hopper dredgers.