| 摘要 |
PURPOSE:To expand the arranging intervals of nozzles by a method in which a pair of high-pressure water jet nozzles at the same levels are inclined to the advancing direction at such an angle that the extended lines of respective jet ports are crossed each other. CONSTITUTION:A plow 4 consists of a casing 10, a pathway 11 for cable A, a conduit 12 for high-pressure water, and high-pressure water jet nozzle groups 13 provided to the conduit 12. The nozzle group 13 consists of 8 nozzles 14-21, in which the extended lines of the 1st, 4th and 8th nozzles 14, 17 and 21 and those of the 2nd, 3rd and 7th nozzles 15, 16 and 20 are crossed at the position determining the width of trench to be excavated by propertly selecting the vertical and horizontal directions of these and the extended lines of the 5th and 6th nozzles 18 and 19 are cross at the middle of the width of the trench. Thus, a desired width of trench can be excavated without close arrangement of these nozzles. |
