JPS6058327B2 - How to install a bottom-mounted offshore structure using a used tanker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for installing a bottom-mounted marine structure using a used tanker.

When constructing a bottom-mounted marine structure such as a breakwater using a used tanker, a mount is set up on the seabed using rubble, etc., the tanker is floated on the sea surface and towed above the mount, and then water is poured inside. The tanker is then submerged on the mount, and solid heavy materials such as concrete or earth and sand are filled inside instead of water and installed on the mount, preventing horizontal movement of the tanker due to waves etc. by the frictional force between the tanker and the mount. are doing.

In order to increase the frictional force between the tanker and the mount to reliably prevent horizontal movement of the tanker, it is possible to increase the coefficient of friction between them, or to increase the friction between the tanker and the solid heavy objects packed inside it. It is necessary to increase the total weight of However, in the case of tankers, since the hull is made of steel, the coefficient of friction between the tanker and the mount is smaller than that of a concrete caisson, and in order to obtain the same frictional force as a concrete caisson, it is necessary to It is necessary to increase the total weight by about 50% compared to the case of a concrete caisson, which is uneconomical.

This invention was made in view of the above-mentioned circumstances, and it is possible to improve the horizontal movement of a used tanker by increasing its resistance to waves, etc., without particularly increasing the total weight of the used tanker and solid heavy objects. The purpose of the present invention is to provide a method for installing a bottom-mounted marine structure using a used tanker, which can reliably prevent the above.

The method according to the present invention is that when a used tanker is installed as a submerged marine structure on a mount on the seabed, the bottom shell plate and the bones attached to this shell plate are placed between the left and right vertical bulkheads of the used tanker in advance in the dock. After cutting both the left and right ends of the wood, the cut parts were lifted up and reattached to the vertical bulkhead to form a recess in the center of the ship's bottom in the left and right direction. , which is characterized by filling the recesses in the bottom of the ship with sand, etc.

According to this invention, the sand filled in the recess in the bottom of the used tanker comes into contact with the top surface of the mount, and the coefficient of friction between the sand and the mount is the same as that between the steel hull and the mount. This increases the frictional force between the tanker and the mount. Therefore, even if the total weight of the tanker and the solid heavy objects packed therein is not particularly increased, the resistance against waves and the like is increased, and horizontal movement of the tanker can be reliably prevented. Embodiments of the present invention will be described below with reference to the drawings. First, as shown in FIG. 1, a used tanker 1 to be used as a bottom-mounted offshore structure is pulled into the dock 2, and the bottom skin 4 between the left and right vertical bulkheads 3 and this skin 4
Both left and right ends of the aggregate 5 including the large bones and small bones attached to it are cut.

Then, lift this cut part with a jack (not shown) and place it back on the vertical bulkhead as shown in FIG.
This creates a recess 6 in the center of the bottom of the ship in the left and right direction.
form. Further, a plurality of vertical pipes 9 extending from the upper deck 8 to the recess 6 are appropriately arranged in the central tank 7 of the tanker 1. On the other hand, a mount 10 is installed on the seabed using rubble at the location where the used tanker is installed, and the tanker 1 modified as described above is pulled out to sea and towed above the mount 10, and then water is poured inside and the mount 10 is raised. Submerge in

Next, solid heavy objects such as earth and sand are poured into the hull, and the tanker 1 is installed at a predetermined position on the mount 10. Finally, as shown in FIG. 3, the recess 6 is filled with sand 11 through the pipe 9, and the tanker is
Complete the installation. In the above embodiment, the top surface of the mount is flat, but a protrusion is provided on the top surface of the mount that fits into the recess in the bottom of the ship when the tanker is sunk. Sand or the like may be filled between the two.

In this way, the horizontal movement of the tanker is more reliably prevented by the convex portion of the mount that fits into the concave portion of the bottom of the ship.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention in the order of steps, and FIG. 1 is a cross-sectional view showing a used tanker at a dock before modification, and FIG.
The figure is a cross-sectional view showing the modified used tanker at the dock, and FIG. 3 is a cross-sectional view showing the used tanker installed on the mount. 1...Used tanker, 2...Dock,
3... Vertical bulkhead, 4... Bottom shell plate, 5...
... Aggregate, 6 ... Concavity, 10 ...
・Mount, 11...Sand.

Claims (1)

[Claims] 1. When installing a used tanker as a bottom-mounted offshore structure by sinking it on a mound on the seabed, the bottom shell plate between the left and right vertical bulkheads of the used tanker and both left and right ends of the aggregate attached to this shell plate shall be After cutting, this cut part is lifted up and reattached to the vertical bulkhead to form a recess in the center of the ship's bottom in the left-right direction.After sinking this used tanker onto a mound on the seabed, sand is poured into the recess in the bottom of the ship. A method for installing a bottom-mounted marine structure using a used tanker, which is characterized by being filled with such materials.