JPH01121408A - Gravity-type dolphin - Google Patents

Abstract

PURPOSE:To control the vertical movement of a gravity-type dolphin by a method in which a vertically movable inner tank is set in an outer tank set on the seabed, and a slab fixed to the upside of the inner tank and supported on the neck piercing the upper wall of the outer tank is connected to an object to be moored. CONSTITUTION:A semi-dividing type concrete inner tank 5 is set in an outer concrete tank 4 set on the rubble mound 3 of the seabed in such a way as to enable sea water to move through the aperture 12 between the tanks 4 and 5 and also the tank 5 to move vertically. The tubular neck 10 is fixed to the upper end of the tank 5, and the slab 15 on the sea surface is supported through the upper wall of the tank 4. The slab 15 and an object 2 to be moored are connected through bolts 17 and a connector 18. The difference of ebb and flow can thus be absorbed and vertical rocking by tidal waves can also be absorbed.

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 is a practical method for mooring large-scale moored objects such as maritime airports and maritime cities.
The dolphin link method and the sinker chain method are known.

In the dolphin cable system, a moored object is moored by driving a pile into the supporting ground and connecting the upper end of the pile that is above sea level to the moored object using a cable chain. The dolphin link method is a construction method in which the upper end of a similar pile and a 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 chain method and sinker chain method, the cable chain is stretched so that it is slack, and in the case of the dolphin link method, the link is stretched. There is greater freedom of movement. Therefore, the degree of restraint of the moored object in the vertical direction is extremely weak, making it impossible to suppress vertical movement caused by waves.

Furthermore, in the case of the dolphin cable type and dolphin link type, the piles are made of steel pipes and are subject 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 10,100 O is required, so the applicability of the location is limited, and there are also major problems such as fishing compensation. Also, in the case of multi-point mooring In this case, it is difficult to control the initial tension applied to each cable chain so that the cables receive an even load.

Furthermore, in the case of the dolphin link system, there are problems such as maintenance of the ring section, durability, auxiliary means for replacing the ring, and the need for a buffer function.

[Purpose of the invention]

Therefore, an object of the present invention is to provide a dolphin that does not have 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 enough to create flow resistance.

Here, it is desirable that the horizontal movement of the moored object is elastically restrained by the outer tank. Additionally, 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 dolphin 1 according to the present invention and a moored object 2 such as a marine airport moored by the dolphin. The gravity dolphin 1 has a concrete outer tank 4 that is submerged in water and installed on a rubble mound 3, and a concrete semi-submersible inner tank 5 that is movable up and down within this outer tank. We are prepared.

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 further includes a small open lower part 8 that communicates the inner chamber of the outer tank with the surrounding sea. Although it is preferable to provide the opening lower at a position below the inner tank 5, it may be provided at another location. The opening 8 is connected to the tubular protrusion 9 of the outer tank 4.
and the tubular neck 10 of the inner tank 5. As will be described later, this open lower part 8 functions to absorb the tidal difference. The outer tank 4 further includes a horizontal reaction force receiving wall 1.
1a is formed, and a rubber fender 11 that elastically supports the moored object 2 in the horizontal direction is attached to this.

The inner tank 5, which is vertically movable within 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 through this gap 12 between the upper outer tank inner part 13 and the lower outer tank inner part 14 of the inner tank 5. , then this gap 12
Flow resistance is generated by this, and vertical movement of the inner tank 5 is buffered.

Note that the lower opening 8 may be made relatively small so that flow resistance also occurs in this opening.

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. Inner tank 5 contains slab 1.
Ballast can be filled and discharged via the openings 16 of 5 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 having 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 or out of the inner chamber of the outer tank 4 through the open lower lower part 8. In addition, when the seawater moves up and down relatively quickly due to waves, the gap 12 between the inner tank 5 and the outer tank 4 is narrow, so the seawater passing through this gap 12 is subject to flow resistance, which prevents the inner tank 5 from moving up and down. Buffer. Therefore, through the slab 15, this inner tank 5
The vertical movement of the moored object connected to the moored object 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, the dolphin can be resurfaced and used for other purposes.

Next, a method for constructing and installing the dolphin will be explained.

(1) The shape and dimensions of the dolphin 1 are determined from various conditions such as the installation water depth, the sea conditions of the installation sea area, and the movement characteristics of the moored object 2.

(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) After completing the construction up to the neck 10 of the inner tank 5, construct the upper wall of the outer tank 4 and the horizontal reaction force receiving wall 11a.

(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 float on the ocean using its own buoyancy and be towed to the installation area.

At this time, the open lower part of the outer tank 4 is temporarily closed 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 has temporarily closed the opening lower and place it in a predetermined position by pouring water into the outer tank 4. The inner tank 5 is in a semi-submersible state.

(9) Towing and installing moored objects. The height is slightly adjusted by adjusting the ballast of the inner tank 5. And the connector 18
The dolphin 1 and the moored object 2 are connected by the dolphin 1 and the moored object 2.

(10) If the stuttering 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 may be insufficient for some reason, restrain the outer tank 4 to the seabed ground using an earth anchor.

The dolphin of the present invention has the following features compared to existing mooring methods:
It has excellent vertical restraint, which expands the scope of application of the moored object loading function, especially for ultra-large artificial ground such as offshore airfields and maritime cities, plant purge on which precision equipment can be mounted, and high wave dissipation effect. It is ideal for offshore hotels, restaurants, etc. that require wide (30m class) large breakwaters and 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 resurfacing is possible.
It can be used 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 the Dolphin is extremely simple in structure, 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 buffers relatively fast vertical movements of the inner tank. This allows it to absorb the tidal difference, and
Vertical oscillations caused by waves can be suppressed. Furthermore, since the outer and inner tanks are made of concrete, they are durable and require little maintenance.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a dolphin according to an embodiment of the present invention;
Figure 2 is a top view of the dolphin in Figure 1;
The figure is a view of the dolphin shown in FIG. 1 cut along the line ■-■, and FIG. 4 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...Gap, 15...Slab,
17.18...Coupling device agent Patent attorney Esaki
Yoshimitsu Mitsu's agent Patent attorney Mitsufumi Esaki Figure 3 Figure 4 Procedural amendments January 7, 1988 Director General of the Patent Office Kunio Ogawa 1, Indication of case Patent Application No. 275677 of 1988 2, Name of the invention: Gravity-type Dolphin 3; Relationship with the person making the amendment: Patent applicant name: Japan Land Development Co., Ltd. 4; Agent address: 8-1 Toranomon 2-chome, Minato-ku, Tokyo (Toranomon Electric Building) 6. Amendment content 1: "and" on page 5, line 9 of the specification is deleted. 2. On the bottom line of page 8, after "Becomes semi-submerged state." 4 "
In addition, if necessary, put sand, ballast, etc. into compartment 6.
Adjust the weight of Dolphin 1. ” is inserted.

Claims (3)

[Claims] (1) An outer tank made of concrete that is submerged in water, a semi-submersible inner tank made of concrete that can be moved vertically within the outer tank, and a container that extends upward from the top of the inner tank through the wall of the outer tank. It is equipped with a slab supported at the upper end of a tubular neck projecting into the outer tank, and a connecting device for connecting this slab and a moored object. A gravity-type dolphin that is formed on the wall and has a small gap between the inner tank and the outer tank to create flow resistance. (2) Claim No. 1 (1) characterized in that horizontal movement of the moored object is elastically restrained by the outer tank.
) Gravity type dolphin described in section. (3) The gravity dolphin according to claim (1), wherein the inner layer can be filled and discharged with ballast.