JPS6346809B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a submarine drilling device, particularly to a submarine drilling device for burying submarine cables.

2. Description of the Related Art Continuous trench excavation equipment is conventionally known, which excavates a burial trench by injecting high-pressure water into the submarine ground when laying a submarine cable, and continuously buries the cable in the trench. In this case, in order to excavate a trench of a constant width, multiple high-pressure water injection nozzles are arranged in parallel, and the intervals between each nozzle are determined relatively closely so that the excavation range of each nozzle is continuous in the width direction. There is a need. Therefore, it is possible to reliably excavate continuous trenches of a certain width, but as the number of nozzles increases, the equipment becomes complicated, especially the piping system, and the amount of water supplied becomes large. Therefore, the cost is high, and there is also the problem that it is difficult to handle the thick water pipes that are sent to the high-pressure seabed.

In order to solve these problems, this invention arranges the high-pressure water injection nozzles at intervals wider than in the conventional case, that is, at intervals that leave unexcavated parts between each nozzle, and places the remaining ground at the rear of the nozzles. The object of the present invention is to provide an undersea drilling rig that is collapsible by a wedge plate.

Hereinafter, the present invention will be explained based on the accompanying drawings.

1 and 2 show the basic structure of the apparatus according to the present invention. That is, the high-pressure water injection nozzles 1 are divided into several groups and arranged vertically in multiple stages, and the nozzles 1 in each group are arranged at regular intervals in the lateral direction. As shown in FIG. 2, the interval between the nozzles 1 is such that the non-excavation portion b remains between the excavation portions a by each nozzle 1, and normally the width of the non-excavation portion b is approximately the same as the width of the excavation portion a.ゞSet at equal intervals. That is, the spacing between the nozzles 1 is usually set to about twice the conventional spacing.

In this way, wedge plates 2 are provided behind the nozzles 1 arranged at relatively wide intervals, corresponding to every other nozzle 1.

The wedge plate 2 is arranged along the depth direction of the excavated groove with its acute angle portion facing the excavation direction, and its width is formed to be larger than the width of the excavated portion a.

As shown in FIG.
The submarine ground c is excavated by moving the device forward while injecting high-pressure water from the excavator. When the seabed ground c is clayey, as shown in Figure 2, unexcavated parts b of a certain width remain, but every other excavated part a has a wedge plate 2 wider than that width. enters, the non-excavated portion b is crushed by the wedge plate 2 and collapses.

Next, FIG. 3 shows a drilling rig 4 and a work barge 5 having a towing mechanism. is mounted so as to be swingable by a hydraulic cylinder 7. The cable A is introduced from the work barge 5 into the plow 3 by means of a guide pipe 8. Each sled section 6 is equipped with a ballast tank 9 and a subsea pump 10 above the ballast tank 9 for generating low-pressure water for excavation. High pressure water, pressurized air, etc. are sent from the work barge 5 via a cable 11.

FIG. 4 shows the internal structure of the plow 3. The casing 12 constituting the plow 3 has an open surface facing the ground c, and has a cable passage 13, two ejector ducts 14, 14', and a low-pressure water supply pipe 1 inside.
5, 15', a high-pressure water supply pipe 16, a pressurized air supply pipe, etc., and a group of low-pressure water nozzles 17 as an excavation part are placed on the upper part of the open surface of the casing 12, and the above-mentioned high-pressure water nozzle 1 is placed on the top of the open surface of the casing 12. They are arranged in several upper and lower groups at the bottom.

The ejector ducts 14, 14' are ejectors 18, 19 provided below the 17 group of low-pressure water nozzles and below the 1 group of high-pressure water nozzles, respectively.
are connected to the earth removal pipes 20 (see Figure 2).
It has been continued. In addition, the above low pressure water supply pipe 1
5 and 15 are connected to the subsea pump 10. The other supply pipe 15' extends below the casing 12 together with a high-pressure water supply pipe 16 and a parallel pressurized air supply pipe (not shown), and low-pressure water and pressurized air are supplied to the high-pressure water nozzle 1. The low-pressure water and pressurized air surround and protect the high-pressure water jet, and the pressurized air prevents cavitation due to the jet.

In addition, as shown in FIG. 5, the above-mentioned wedge plate 2 is
It is formed to be long in the vertical direction so as to be common to all groups of high-pressure water nozzles 1.

Since the plow 3 is constructed as described above, it is tilted at an angle along the ground c by the hydraulic cylinder 7, and the excavation rig 4 is towed by the work barge 5.
Pressure water is injected from the low-pressure water nozzle 17 and the high-pressure water nozzle 1 to excavate a cable burying trench of the required width, and while laying the cable A in the burying trench, the earth and sand are discharged from the earth discharge pipe 20 and the cable A is buried. . During the above-mentioned excavation, the low-pressure water nozzle 17 is provided at the top and the high-pressure water nozzle 1 is provided at the bottom, so the low-pressure water nozzle 17 excavates a relatively soft layer, and the high-pressure water nozzle 1 excavates a relatively hard layer. I will do it.

In this invention, the high-pressure water nozzles are arranged at intervals such that the unexcavated portion remains as described above, and the remaining ground is collapsed by the wedge plate placed at the rear of the nozzle. When excavating an excavation trench, the number of nozzles is reduced compared to the conventional case. Therefore, the device is simplified, the water pipes are easier to handle, and the amount of water used is also reduced, which has the effect of lowering work costs.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the plow section, Fig. 2 is a perspective view of the excavation section for explaining the principle of the invention, Fig. 3 is a perspective view of the entire excavation device, and Fig. 4 is a sectional view of the plow section.
FIG. 5 is a partially enlarged sectional view of the plow portion. 1... High pressure water nozzle, 2... Wedge plate, 3...
Plow, 4...Drilling equipment.

Claims (1)

[Scope of Claims] 1. In a submarine drilling device that excavates a trench of a certain width by injecting high-pressure water into the seabed ground, a plurality of high-pressure water nozzles are arranged at intervals such that a non-excavated portion remains between each nozzle, A submarine drilling device characterized in that a wedge plate corresponding to every other nozzle and having a width wider than the excavation width by the nozzle is provided behind the nozzle. 2. The submarine drilling equipment according to claim 1, wherein the combination of the nozzle and wedge plate described above is installed in multiple stages in the vertical direction.