METHOD AND TOOL FOR SEABED EXCAVATION

摘要

For excavation of a clay seabed, particularly in a coffer dam to expose a buried pipeline therefor a minimum of three water nozzles producing water jets and the associated effects 16, 17 and 18 are used. The nozzles are mounted on a disc 12 which can move horizontally and vertically and which rotates in a horizontal plane. The effect 18 (if operated alone) would produce a trench 22 having sloping sides. The two effects 16, 17 enable a trench having vertical sides to be cut and enable the disc 12 to be moved downwardly until obstructed by the base of the trench. The three nozzles are equiangularly spaced about the axis. The rotation of the disc 12 makes the effect of the nozzles possible.