A THEORY OF SOIL RIPPING BY A SUBMERGED WATER JET AND THE DESIGN OF JET SOIL RIPPERS FOR DREDGES

摘要

1. Pumps with a pressure head of about 30 m capable of producing a 20 - 25 m nozzle pressure head are recommended for efficient jet soil ripping. 2. Water supply of about 30% with respect to the soil pump flow rate is sufficient for jet soil ripping. 3. Hydrojet rippers fitted with a single nozzle of large diameter are more efficient than multi-nozzle rippers; in the latter, the jet energy undergoes a faster decay. 4. The nozzle of a hydrojet ripper should be positioned at the shortest possible distance from the slope bottom; its position can be controlled by means of a hydralic drive or by use of readily interchangeable sleeves of different length. 5. Field tests of axial submersible pumps (ITT Flygt) at a pressure head of 1 - 1.5 m and a flow rate close to that of the soil pump are recommended with a view to improving the jet soil ripping technology and energy saving.