JPH0520526B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gravity dolphin for mooring moored objects, particularly floating structures.

[Conventional technology]

For example, the Dolphin chain method, the Dolphin link method, and the sinker chain method are known as practical construction methods for mooring large-scale moored objects such as marine airports and maritime cities.

In the Dolphin cable chain method, a moored object is moored by driving a pile into the supporting ground and connecting the upper end of the pile, which is above sea level, to the moored object using a cable chain. The dolphin method is a construction method in which the upper end of a similar pile and the moored object are connected by a link. Furthermore, the sinker chain method is a construction method in which a sinker submerged in the sea and a moored object are connected by a large diameter cable chain.

[Disadvantages of conventional technology]

In order to allow the moored object to move up and down in response to the ebb and flow of the tide, in the case of the above-mentioned Dolphin link chain system and sinker chain system, the cable chain is stretched so that it is slack, and in the case of the Dolphin link system, The degree of freedom of link movement is increasing. Therefore, the degree of vertical restraint of the moored object is extremely weak,
It is not possible to suppress vertical oscillations caused by waves.

Furthermore, in the case of the Dolphin cable chain system and the Dolphin link system, the piles are made of steel pipes and are prone to rust, so there is a problem in durability.

Furthermore, in the case of the sinker chain method, a vast sea area (chain length of 500 to 1000 m) is required, so
The applicability of location is limited, and there are also major problems such as fisheries compensation. Furthermore, in the case of multi-point mooring, it is difficult to manage the initial tension applied to each cable chain so as to distribute the load evenly.

Furthermore, in the case of the Dolphin link system, maintenance of the ring part, durability, auxiliary means for ring replacement,
There are issues such as the need for a buffer function.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a dolphin without the above-mentioned drawbacks.

[Means to achieve the purpose]

To achieve this objective, the present invention provides an outer tank made of concrete that is submerged in water, a semi-submersible inner tank made of concrete that is movable vertically within the outer tank, and an upper end of the inner tank. A slab supported at the upper end of a tubular neck projecting upward through the wall of the outer tank, and a connecting device for connecting the slab to the moored object, communicating the inner chamber of the outer tank with the periphery of the outer tank. A small opening is formed in the wall of the outer tank, and the gap between the inner tank and the outer tank is made small to create flow resistance.

Here, it is desirable that the horizontal movement of the moored object is elastically restrained by the outer tank. Furthermore,
It is desirable to be able to fill and drain the inner layer with ballast.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 4 show a gravity type dolphin 1 according to the present invention and a moored object 2 such as a marine airport moored by the dolphin. Gravity-type Dolphin 1 is submerged in water to create a rubble mound 3
It has an outer tank 4 made of concrete installed above, and a semi-submersible inner tank 5 made of concrete that is movable in the vertical direction within the outer tank.

The outer tank 4 is double walled to form a compartment 6 (see Figure 3) for containing sand ballast etc. and to increase the strength of the tank. The outer tank 4 is further provided with small openings 7, 8 which communicate the inner chamber of the outer tank with the surrounding sea. It is preferable to provide the opening 7 at a lower position of the inner tank 5, but it may be provided at another location. The opening 8 is an annular gap formed between the tubular projection 9 of the outer tub 4 and the tubular neck 10 of the inner tub 5. These openings 7 and 8 function to absorb the difference in tides, as will be described later. The outer tank 4 is further formed with a horizontal reaction force receiving wall 11a, which includes a rubber fender 1 that elastically supports the moored object 2 in the horizontal direction.
1 is attached.

Inner tank 5 that is movable up and down inside the outer tank
is formed as a piston with a square cross section, and a narrow gap 12 is formed between its side wall and the side wall of the outer tank 4. As a result, when the inner tank 5 moves up and down, seawater moves between the upper outer tank inner part 13 and the lower outer tank inner part 14 through this gap 12. At this time, flow resistance is generated by the gap 12, and the vertical movement of the inner tank 5 is damped. Note that the openings 7 and 8 may be made relatively small so that flow resistance also occurs in these openings. The above-mentioned tubular neck 10 is connected to the upper end of the inner tank 5, and this neck extends through the upper wall of the outer tank 4 to above the sea level and supports a slab 15 at its upper end. The inner tank 5 can be filled and drained with ballast via the openings 16 in the slab 15 and the tubular struts 10.

The slab 15 is connected to the moored object 2 by a highly rigid connecting device consisting of a bollard 17 and a connecting member 18.

In the case of the Dolphin of the above structure, the inner tank 5 floats due to the buoyancy of the seawater, and therefore moves up and down in the same way as the moored object 2 when the sea level rises and falls due to tides or waves. When the inner tank 5 slowly moves up and down due to the ebb and flow of the tide, seawater flows out or flows into the inner chamber of the outer tank 4 through the openings 7 and 8. Also, when moving up and down relatively quickly due to waves, since the gap 12 between the inner tank 5 and the outer tank 4 is narrow,
The seawater passing through this gap 12 is subjected to flow resistance and buffers the vertical movement of the outer tank 5. Therefore, the vertical movement of the moored object connected to this inner tank 5 via the slab 15 is also damped.

The inner tank 5 can be filled or discharged with ballast water as described above. Therefore, it is possible not only to adjust the height during installation, but also to respond to changes in water depth and construction conditions. Additionally, by discharging the seawater in the outer tank and the ballast water in the inner tank, Dolphin can be resurfaced and used for other purposes.

Next, a method of constructing and installing the Dolphin will be explained.

(1) Installation water depth, sea conditions in the installation area, moored object 2
The shape and dimensions of the Dolphin 1 are determined based on various conditions such as the oscillation characteristics of the Dolphin 1.

(2) If the weight W of the outer tank 4 exceeds the capacity of the hoist ship (W≧3500 tons), construct the bottom wall or side wall of the outer tank using a dry dock or floating dock.

(3) An inner tank 5 is constructed inside this outer tank 4.

(4) When the construction up to the neck 10 of the inner tank 5 is completed,
The upper wall of the outer tank 4 and the horizontal reaction force receiving wall 11a are constructed.

(5) A slab 15 is integrally constructed on the upper part of the neck 10 of the inner tank 5.

(6) Once Dolphin 1 is completed, it will surface on the ocean using its own buoyancy and be towed to the installation area. At this time, the opening 7 of the outer tank 4 is temporarily closed off with a plug or the like.

(7) In the installation sea area, consider the supporting ground in advance and complete appropriate support methods in advance.

(8) Remove the plug that temporarily closed the opening 7, and pour water into the outer tank 4 to sink it into a predetermined position. The inner tank 5 is in a semi-submerged state. Incidentally, if necessary, sand, ballast, etc. are put into the compartment 6 to adjust the weight of the Dolphin 1.

(9) Tow and install moored objects. The height is slightly adjusted by adjusting the ballast of the inner tank 5. Then, the dolphin 1 and the moored object 2 are connected by the connecting tool 18.

(10) If the water level changes due to a change in the weight of the moored object 2, this can be dealt with by adjusting the ballast of the inner tank 5.

(11) If there is a concern that the weight is insufficient for some reason, restrain the outer tank 4 to the seabed ground using an earth anchor.

The dolphin of the present invention has much better vertical restraint than existing mooring methods,
The scope of application of the function of mounting moored objects has expanded, especially on ultra-large artificial ground such as offshore airfields and maritime cities, plant purge on which precision equipment can be mounted, wide (30m class) large wave-dissipating banks with high wave-dissipating effects, and comfortable It is ideal for offshore hotels, restaurants, etc. that require comfortable living conditions. In addition, the degree of mooring restraint is high, the applicable sea conditions are widened, the need for wave-dissipating equipment can be reduced, and the area required for installation in the sea area is significantly smaller compared to the cable chain method, making it highly economical and locationally adaptable. ing. Furthermore, by using the ballast function, the height can be easily adjusted, and it can be re-floated, making it possible to use it for other purposes. In addition, it is possible to respond to slight changes in water depth by adjusting the inner tank ballast function and the rubble mound. Furthermore, the equipment attached to Dolphin has an extremely simple structure, is easy to replace, uses few steel parts, and is highly durable and easy to maintain. Furthermore, since the inner tank has a floating structure, it has excellent earthquake resistance.

〔Effect of the invention〕

As explained above, the dolphin according to the present invention moors moored objects with a semi-submersible inner tank that is movable up and down in the outer tank, and only allows relatively fast vertical movement of the inner tank. Since it is designed to be buffered, it is possible to absorb the tidal difference and suppress the vertical movement caused by waves. Furthermore, since the outer and inner tanks are made of concrete, they are durable and require little maintenance.

[Brief explanation of the drawing]

1 is a longitudinal sectional view of the dolphin according to an embodiment of the present invention, FIG. 2 is a view of the dolphin shown in FIG. 1 seen from above, and FIG. 3 is a view of the dolphin shown in FIG.
FIG. 4, a diagram cut along a line, is a plan view showing a state in which a large floating structure is moored by the dolphin of the present invention. 1...Dolphin, 2...Moored object, 4...Outer tank, 5...Inner tank, 7, 8...Opening, 10...Neck, 12...Between, 15...Slab, 17, 18
...Connection device.

Claims (1)

[Scope of Claims] 1. An outer tank made of concrete that can be submerged in water, a semi-submersible inner tank made of concrete that can be moved vertically within the outer tank, and a wall of the outer tank that extends from the top of the inner tank. The vessel comprises a slab supported at the upper end of a tubular neck projecting upward through the vessel, and a connecting device between the slab and the moored object, with a small opening for communicating between the inner chamber of the outer vessel and the periphery of the outer vessel. A gravity-type dolphin is formed on the wall of the outer tank, and the gap between the inner tank and the outer tank is made small to create flow resistance. 2. The gravity-type dolphin according to claim 1, wherein the horizontal movement of the moored object is elastically restrained by the outer tank. 3. The gravity-type dolphin according to claim 1, characterized in that the inner layer can be filled and discharged with ballast.