JP3595906B6 - Buoyancy adjustment device and method of using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a buoyancy adjusting device capable of easily adjusting buoyancy by adjusting a water surface position of water entering from a bottom surface of an airtight space.
SOLUTION: A buoyancy adjusting device for imparting buoyancy to an underwater structure, wherein an airtight space having only a bottom surface is formed, and the buoyancy is adjusted by adjusting a water surface position of water entering from the bottom surface. It is characterized by this. Here, the airtight space is formed of a shield that can retain its shape even when water pressure is applied from outside, and the upper surface is formed of an airtight material attached to the underwater structure. The shield and the airtight material An airtight structure can be formed between the two.
[Selection] Figure 1

Description

The present invention relates to a buoyancy adjusting device for adjusting the buoyancy of a structure disposed in water and a method of using the same.

A submarine tunnel is an example of an underwater structure installed on the bottom. As a method for constructing a submarine tunnel, there is a conventional submerging method in which boxes are connected to each other on the bottom to construct a submarine tunnel.
In the submergence method, the bottom tunnel is constructed by towing the box constructed in the production yard to the destination and sinking it. Usually, since the box to be laid has a length of about 100 m to 140 m, a box was manufactured by constructing a large production yard like a dock at a shipyard near the construction site. The box made here is too heavy to be lifted by a normal crane, etc., so the front and back openings of the box are closed with bulkheads and floated on the water for towing. It was transported to the ground.
The sinking box that has been towed to the surface of the planned site will be gradually submerged by injecting water into the ballast tank provided inside the box surrounded by the bulkhead. Here, Patent Document 1 discloses an invention in which a ballast tank is manufactured in a bag shape using a rubber sheet.
Further, Patent Document 2 discloses an invention in which a box is suspended by a bag-like float filled with gas.
JP 2000-257093 A Japanese Patent Publication No. 5-14076

There are the following problems in the above-described conventional method for burying a burial box.
<1> When a ballast tank is manufactured using a rubber sheet bag as described in Patent Document 1, it is necessary to have a complicated structure such as providing an exhaust valve in addition to water injection. In addition, it is necessary to attach a frame or use a reinforcing sheet to control deformation. The bag-shaped ballast tank manufactured in this way is expensive to manufacture, but since the amount of water that can be injected is limited, a large number of ballast tanks must be attached to the inside of the submerged box as necessary.
<2> When the buoyancy of the box is adjusted by the bag-like floating body, the internal pressure changes depending on the water depth, and thus the usable depth of the buoyant body is limited. Further, in order to compensate for the increase in the external water pressure and the decrease in the volume of the buoyant body, it is necessary to increase the number of buoyant bodies.
<3> When the box is suspended by a bag-like float, the buoyancy cannot be adjusted later.

In order to solve the problems as described above, the buoyancy adjustment device of the present invention is a buoyancy adjustment device for imparting buoyancy to an underwater structure having openings at both ends in the extending direction, the underwater structure. An airtight space is formed by an airtight shielding material made of a flexible material that partially shields the opening of the water and an airtight material attached to the inner wall surface of the underwater structure so as to be continuous with the shielding material. The shielding material is fixed to the upper and side wall surfaces of the opening, the lower end is installed in a state that does not reach the floor, and an air supply pipe for supplying gas from the opened bottom surface of the airtight space is disposed. The buoyancy adjustment device is characterized in that the shielding material is supported by a support material that spans from the upper part to the lower part of the opening and from the upper part to the side part or between the side parts.
Also, lift the underwater structure equipped with the buoyancy adjustment device described above with a crane,
It is characterized by a method of using a buoyancy adjusting device that imparts buoyancy to the underwater structure by supplying gas from the bottom surface of the hermetic space.

Moreover, the method of using the buoyancy adjustment device of the present invention is such that the underwater structure provided with any of the buoyancy adjustment devices described above is suspended by a crane or the like, and gas is supplied from the bottom surface of the airtight space. This is a method of imparting buoyancy to a structure.

The method for constructing a submarine tunnel of the present invention can obtain at least one of the following effects by means for solving the above-described problems.
<1> The inner space of the box to be laid can be used effectively as a ballast tank.
<2> Since the partition wall made of concrete that requires removal work by destruction is not used, the construction and removal work of the partition wall can be omitted.
<3> Since the pressure difference between the inside and outside of the airtight space serving as a buoyant body becomes a hydrostatic pressure corresponding to the height of the airtight space, it can be used regardless of the depth of the settling / moving water.
<4> The adjustment of the buoyancy can be managed by the water level inside the airtight space, so that the management is easy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1> Buoyancy adjustment device The buoyancy adjustment device is a device for imparting buoyancy to an underwater structure. The buoyancy adjusting device is constituted by an airtight space having only a bottom surface opened.
The outer periphery of the airtight space is formed by a shield, a shielding material 2, an airtight material 21 or an inner wall surface of an underwater structure described later, and only the bottom surface is opened so that water can freely enter from below. Then, the buoyancy is adjusted by adjusting the water surface position of the water that has entered from the bottom surface.

<2> Underwater structure An underwater structure is a structure installed in water or in the bottom of the water. For example, the penetration type box 1 which is a box for constructing a water bottom tunnel corresponds to this. Further, when the penetrating box 1 is divided into a bottom plate part, a side wall part, a ceiling part, and the like, each member becomes an underwater structure.
The cross-sectional shape of the penetrating box 1 can be arbitrarily selected, such as a rectangle or an ellipse. Normally, a penetrating box 1 having a rectangular cross section of a box culvert type as shown in FIG. 2 is used. Moreover, the bottom plate part of the penetration type box 1 can be formed into a footing shape protruding from the side wall as necessary.
The penetrating box 1 is a box having both ends in the extending direction as openings 11. For this reason, when submerged in water, water can freely enter inside the box from the outside. The box length of the penetration type box 1 is, for example, about 20 to 30 m. The penetrating box 1 used in the present invention is preferably manufactured to a size that can be lifted and transported by a crane.

For example, protrusions 51 and 52 or depressions are preferably formed at the end of the penetrating box 1 in the penetrating direction so as to have a fitting shape. For example, a part of one end face of the penetrating box 1 is protruded and constructed, and a cushioning material such as a rubber sheet is pasted on the surface to form a rectangular shear key type protrusion 51 (see FIG. 2). . Further, a cylindrical projection 52 is provided by embedding a steel pipe or the like in the end face. Then, the other end face of the penetrating box 1 is provided with a depressed portion that fits into the protruding portion 51 and the protruding portion 52. In this way, if a plurality of the same penetrating box 1 are to be joined, the protrusions 51 and 52 of the new penetrating box 1 are fitted into, for example, the recessed portion of the existing penetrating box 1. By doing so, it is possible to construct a joint that can resist shearing force. The protrusions 51 and 52 and the depressed portion may be provided on the same end surface. In that case, what is necessary is just to make it the combination of the protrusion parts 51 and 52 and the depression part in the opposing part of the penetration type box 1 to join.

<3> Shielding Body The shielding body is a member that partially shields the two openings 11 of the penetrating box 1. “Partial shielding” does not mean that the entire surface of the opening 11 is shielded to completely prevent water from entering, but, for example, the lower part of the opening 11 is left open. For this reason, the shield is fixed to the upper and side wall surfaces near the opening 11, but the lower end does not reach the floor plate, and is free from the gap between the lower end of the shield and the floor plate of the penetrating box 1. A structure that allows intrusion of outside water.
The shield needs to be configured so that the shape can be maintained even when water pressure is applied from the outside. Here, “the shape can be maintained” does not indicate that the deformation is not allowed at all, but indicates that the shape can be maintained to the extent that a desired inner space size can be secured. Therefore, when the shape can be maintained only by the shielding material 2, the shielding body can be configured by only the shielding material 2, and the support material 3 described later is arranged depending on the material of the shielding material 2.

For example, the shielding material 2 can be made of a flexible material such as a sheet that can be easily installed and removed, or a plate material such as a steel plate. Since the shielding material 2 needs to be a material that prevents the gas injected or existing inside the airtight space from leaking outside, the airtight material 21 having excellent airtightness is used. As the airtight material 21, for example, a vinyl chloride film structure member can be used.
Moreover, since the shielding material 2 receives water pressure during the installation, it is necessary to make the shielding material 2 a member that can withstand the water pressure with a reinforcing material 22 such as a reinforcing sheet. For example, the flexible airtight material 21 and the reinforcing material 22 can be bonded to form a double-structured shielding material 2. As the reinforcing material 22, for example, a polyester fiber sheet film-forming structural member can be used.

Moreover, the fixing method of an airtight structure is employ | adopted for fixing of the shielding material 2 so that gas may not leak from the part which fixed the shielding material 2 to the top plate or side wall of the penetration type | mold box 1. FIG. For example, the shielding material 2 is fixed by combining the plate 24 and the embedded bolt 23 that continuously press the end of the shielding material 2 (see FIG. 4).
Depending on the finished state of the inner wall surface of the penetrating box 1, gas can be held in the space surrounded by the shielding material 2 and the inner wall surface of the penetrating box 1, but when the inner wall surface has low airtightness It is preferable to improve the airtightness of the airtight space by attaching the airtight material 21 to the inner wall surface such as the top plate or the side wall. In this case, the end of the airtight member 21 attached to the wall surface and the end of the shielding member 2 are made continuous (see FIG. 4).

<4> Support Material The support material 3 is a member arranged to support the shielding material 2. Since external water pressure acts on the shielding material 2 during installation, when the shielding material 2 is made of a flexible material, the shielding material 2 is deformed by the external water pressure or its change, or is largely bent to fix the airtight structure. The part may be damaged. In order to prevent such a situation, the support member 3 is disposed to support the shielding member 2.
For the support material 3, for example, a wire cable or a steel rod can be used. For example, a plurality of cylindrical anchoring portions 31 are attached to the surface of the shielding member 2 at intervals, the support member 3 is inserted into the mooring portion 31, and the support member 3 is hung from the upper portion to the lower portion of the opening portion 11 (see FIG. 2 and 3). The arrangement direction of the support member 3 is not limited to the upper and lower sides, and the upper part and the side part can be connected obliquely or the side parts can be connected (not shown).

<5> Air Supply Pipe The air supply pipe 4 is an instrument that sends gas into the airtight space. One or a plurality of exhaust ports 41 are provided on the side surface of the air supply pipe 4, and the gas fed through the connected air hose 42 or the like is supplied from the exhaust port 41 to the inside of the airtight space. A gas such as compressed air is fed into the air hose 42 from a compressor or the like disposed on the ship or on land. The air supply pipe 4 can be inserted through a gap between the lower end of the shielding member 2 and the bottom plate of the penetrating box 1 and can be installed on the bottom plate.
Since the penetrating box 1 has a penetrating structure that allows outside water to enter inside, the weight of the penetrating box 1 in water can be adjusted by the amount of gas fed from the air pipe 4. That is, when gas is fed from the air pipe 4, the internal water staying inside the box is discharged from the gap between the lower end of the shielding material 2 and the bottom plate of the penetrating box 1, and the water level 43 inside the box is lowered. . As a result, the weight in water of the penetrating box 1 is reduced by the amount of drained water, and the box can be balanced during settling and the settling speed can be adjusted. Even if the water depth increases and the water pressure rises, the water level 43 gradually increases and the buoyancy gradually decreases if the gas is not sent, but the buoyancy can be maintained by sending the gas. .

<6> Water-stopping material The water-stopping material is disposed at the end of the box in order to increase the water-stopping property at the joint between the penetrating boxes 1. As the water stop material, for example, a primary water stop material 61 and a secondary water stop material can be used.
The primary water blocking material 61 is, for example, a linear water blocking seal disposed on the end surfaces where the penetrating boxes 1 are in contact with each other, and is annularly attached to the end surface of the penetrating box 1 as shown in FIG. As the primary waterproof material 61, a known waterproof material such as a rubber seal or a gasket can be used. The primary water blocking material 61 is deformed by its own weight, inertial force, pulling force, and the like when the penetrating box 1 is pressed against the existing penetrating box 1 and exhibits water-stopping properties.
The secondary water stop material is a water stop material that is attached from the inside after, for example, temporary joining is completed and the inside of the penetrating box 1 is drained. For example, a waterproof rubber with a Ω cross section can be used. The secondary waterproof material is attached so as to straddle between the penetrating boxes 1 and 1.

  Embodiments of the present invention will be described below with reference to the drawings.

<1> Manufacture of box The penetrating box 1 is manufactured in a production yard on land. In the production yard, transfer devices such as water casters and roller conveyors that use fluid pressure will be installed. Then, the floor plate, the side wall, and the ceiling of the penetrating box 1 are manufactured in order by a flow operation. At this time, if a match casting method for manufacturing the next through-type box 1 using the end face of the previously formed through-type box 1 as a formwork is adopted, the joint can be manufactured with high accuracy.
The shielding material 2 and the support material 3 are attached to the opening 11 of the penetration type box 1 in which the casing is completed, and the airtight material 21 is attached to the inner wall as necessary to form the penetration type box 1. In addition, an air supply pipe 4 is provided in the penetrating box 1 so that gas can be sent into the inside.
The completed penetrating box 1 is lifted with a crane or the like using a suspension wire 71 and transported to a destination.

<2> Sinking the box (Figure 1)
The place where the penetrating box 1 is to be laid is preliminarily drilled or excavated as necessary, and a basic crushed stone or a bag-like mortar pack is laid.
Sinking is performed after the penetrating box 1 is transported to above the settling location. An air hose 42 is connected to the end of the air supply pipe 4 before the installation. The penetrating box 1 has a structure in which outside water can be freely submerged through the gap between the lower end of the shielding material 2 and the floor board. Therefore, when the sinking is started, the outside water enters the inside of the penetrating box 1 and the water level inside 43 begins to rise gradually. As the water level 43 rises, the weight of the penetrating box 1 in water increases, and the box gradually sinks.
The buoyancy of the box can be adjusted by adjusting the internal water level 43 according to the amount of gas fed from the compressor through the air hose 42 into the space partitioned by the shielding member 2 of the penetrating box 1. The water level 43 inside the box can be measured by a wave height meter installed inside the box. Further, the water level can be adjusted while looking at the measured value of the pressure gauge that measures the pressure of the gas inside the box. Thus, by penetrating while adjusting the water level 43 inside the box, the penetrating box 1 can be easily soft-bottomed at an accurate position.
In addition, the buoyancy adjusting device of the present invention can be used regardless of the depth of water to be set and moved because the difference in pressure between the inside and outside of the airtight space serving as a buoyant body becomes a hydrostatic pressure corresponding to the height of the airtight space.

<3> Joining of Boxes The penetrating box 1 is laid down next to the existing penetrating box 1 that has been sunk in advance at the bottom of the water. For example, a provisional receiving part is provided in the existing box, and is engaged with the provisional receiving part of the penetrating box 1 that sinks to a slightly separated position. And the penetration type box 1 is drawn near and joined to the existing box side using a publicly known drawing jack etc. Here, when the protrusion parts 51 and 52 and the depression part are provided in the end surface of the penetration type box 1 and the existing box, both are fitted and joined.
When the penetrating box 1 and the existing box collide, the primary water blocking material 61 is deformed and the primary water blocking is completed. A connecting steel rod or the like is placed between the penetrating box 1 and the existing box to perform temporary bonding.
After the penetration type box 1 is laid, the foundation is constructed by injecting basic mortar into the lower part of the penetration type box 1 until the strength of the basic mortar is fully expressed. It can be left as it is to prevent excessive ground pressure from acting.
The bottom tunnel is extended by repeating the setting and joining of the penetrating box 1 described above. Here, when the water bottom tunnel is extended, a box provided with a partition in one opening portion 11 is arranged at predetermined intervals. And the secondary water stop is performed after draining the range partitioned off by the two partition walls. Drainage can be performed using the air pipe 4, for example. Moreover, secondary water stop is performed by attaching a secondary water stop material so that the junction part between penetration type boxes 1 and 1 may be straddled from the inside of a bottom tunnel.
And it integrates by introduce | transducing a prestress with the PC steel wire which let the some penetration type | mold box 1 pass inside the housing. In addition, the submerged tunnel will be covered with soil if necessary.

Explanatory drawing of the Example of the buoyancy adjustment apparatus of this invention. The perspective view of the Example of the penetration type box provided with the buoyancy adjustment apparatus. The front view of the Example of the penetration type box provided with the buoyancy adjustment apparatus. Expansion explanatory drawing of the Example of the fixing | fixed part of a shielding material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Through-type box 11 ... Opening part 2 ... Shielding material 21 ... Airtight material 22 ... Reinforcing material 3 ... Supporting material 4 ... Air supply pipe 41 ... Exhaust port

Claims (2)

A buoyancy adjusting device for imparting buoyancy to an underwater structure having openings at both ends in the stretching direction,
An airtight shielding material made of a flexible material that partially shields the opening of the underwater structure;
An airtight space is formed by an airtight material attached to the inner wall surface of the underwater structure so as to be continuous with the shielding material,
The shielding material is fixed to the upper and side wall surfaces of the opening, and the lower end is installed without reaching the floor,
An air supply pipe for supplying gas from the opened bottom surface of the airtight space is disposed ,
The shielding material is supported by a support material that spans from the upper part to the lower part of the opening, from the upper part to the side part or between the side parts,
Buoyancy adjustment device.
The underwater structure provided with the buoyancy adjusting device according to claim 1 is lifted by a crane,
Giving buoyancy to the underwater structure by supplying gas from the bottom surface of the airtight space,
How to use the buoyancy adjuster.

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