Underwater pipe-laying method - comprises dumping layer of stones on pipe immediately after laying in trench dredged in sea or river bed

摘要

The method lays a pipe underwater and which can be lighter than water. A trench is formed in the sea or river-bed and filled in after the pipe has been laid in it. Immediately after the pipe (3) has been laid in the trench, a layer of stones (7) is dumped on top of it. The trench can be formed by nozzles, from which water is discharged against the material to be removed. These are used to hold the trench open until the pipe and stones have been laid in it.