JP2792553B2 - Breakwater caisson and method of connecting them - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a caisson for breakwaters and a method for connecting them.

[0002]

2. Description of the Related Art Breakwaters for protecting coastal areas from damage from storm surges and tsunamis are often constructed using so-called caisson, which is a concrete box-shaped structure.

In the construction of breakwaters, first, a plurality of caissons manufactured in a yard of a shipyard or the like are towed offshore, and then these caissons are successively landed offshore. In order to make effective use, breakwaters are being installed more and more offshore, and accordingly, large caisson that can withstand deep water and high waves is required, and their manufacturing costs are also reduced. Has increased.

On the other hand, as a measure to solve these situations,
It has been reported that the cross-sectional dimension of a caisson can be reduced by increasing the length of the caisson to smooth the wave force.

That is, since the amplitude of a wave involves a phase difference spatially and temporally, if the caisson can be lengthened to a certain extent, the time at which the wave force acting on the caisson peaks depends on the position of the caisson little by little. As a result, the maximum value of the wave force acting on the entire caisson is relaxed from the sum of the maximum value of the wave force per unit area over the entire caisson.

Thus, it is theoretically or experimentally possible to reduce the design load of the caisson by utilizing the smoothing of the wave force and to reduce the cross-sectional dimension.

[0007]

However, in consideration of the scale of the manufacturing yard, the capacity of the crane, the convenience at the time of towing / installation, the effect of wave force at the time of towing, etc., the length of the caisson is naturally about 10 to 20 m. It is practically difficult to manufacture a large caisson capable of smoothing the above-mentioned wave pressure.

For this reason, the design load of the caisson cannot be reduced, so that a caisson having a large cross section has to be manufactured, which causes an increase in manufacturing, towing and installation costs of the caisson, and consequently an increase in the construction cost of the entire breakwater. Had become.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a breakwater caisson and a method of connecting the same, which can be made longer while avoiding problems during production or transportation. Aim.

[0010]

In order to achieve the above object, a breakwater caisson according to the present invention has predetermined connecting recesses formed at both ends, and one end of the caisson is connected to the other end. And a through hole for a PC steel material penetrating therethrough.

In the caisson for breakwater of the present invention, a predetermined connecting concave portion is formed at one end and a space for fixing a PC steel material is formed at the other end. On the other side, a through hole for a PC steel material penetrating is provided.

Further, a caisson for a breakwater according to the present invention is provided with a predetermined water stopping means around the connecting concave portion according to any one of claims 1 to 2.

In the caisson structure for a breakwater according to the present invention, a predetermined connecting concave portion is formed at one end, and a space for fixing a PC steel material is formed at the other end, and further from one of the ends. A pair of end caissons having a through hole for PC steel penetrating the other side are made adjacent to each other so that the connecting recesses face each other, and a predetermined PC steel is inserted into the through hole for PC steel to fix the PC steel. It is established in space.

In the caisson structure for a breakwater according to the present invention, a predetermined connecting concave portion is formed at one end and a space for fixing a PC steel material is formed at the other end, and further, from one of the ends. A pair of end caissons having a through hole for PC steel penetrating the other side, and a predetermined connecting concave portion formed at both ends and a P penetrating from one end to the other end.
An intermediate caisson provided with a through hole for a C steel material is arranged adjacent to the connecting concave portion of the end caisson so that the connecting concave portion of the intermediate caisson faces the connecting concave portion. Through the through hole for PC steel and the through hole for PC steel of the intermediate caisson and fixed in the PC steel material fixing space.

In the method for connecting a breakwater caisson according to the present invention, a plurality of breakwater caissons provided with through holes for PC steel are formed at least at one end of each breakwater caisson. Arranging the connecting recesses so as to face each other, and adjoining the breakwater caisson via predetermined water stopping means, and preventing the water from entering from outside by the water stopping means, A step of draining water accumulated in the concave portion, a step of inserting a predetermined PC steel into the PC steel through-hole, a step of introducing a prestress to the PC steel, and a step of applying the PC steel to the plurality of caisson for breakwaters. And fixing the cement steel into the PC steel material fixing space formed in the two end caissons arranged at both ends, and injecting cement grout into the through hole for the PC steel material. Than it is.

[0016]

In order to connect the breakwater caissons of the present invention to each other, first, a plurality of breakwater caissons provided with through holes for PC steel are connected to the connecting recess formed at at least one end of each of the breakwater caissons. They are arranged so as to face each other.

Here, the caisson for breakwater may be composed of only a pair of end caissons having a connecting recess at one end and a space for fixing a PC steel material at the other end, or a caisson of these end caissons. An intermediate caisson having connection concave portions formed at both ends may be interposed therebetween.

Next, the caisson for breakwater is placed adjacent to the caisson via a predetermined water stopping means, and the water remaining in the connecting recess is drained while preventing water from entering by the water stopping means.

Then, the caisson for breakwater adheres to each other due to the water pressure, and almost no water enters the connecting recess.

Next, a predetermined PC steel material is inserted into the PC steel material through hole, and a predetermined prestress is introduced.

Next, the PC steel material is fixed in the PC steel material fixing space, cement grout is injected into the PC steel material through hole, and the breakwater caissons are connected to each other.

The caisson for breakwater connected in this way is
After the connection, they are integrated into a long caisson, so that the design load can be reduced more than before by introducing wave pressure smoothing during design.

For this reason, compared with the case where they are not integrated,
It becomes possible to greatly reduce the cross-sectional dimension of the caisson.

[0024]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing a caisson for a breakwater of the present invention and a method of connecting the same.

FIG. 1 is a plan view and a sectional view taken along lines AA and BB of an intermediate caisson 1 as a breakwater caisson according to this embodiment.

As can be seen from the drawing, the intermediate caisson 1 of this embodiment has two side walls 3 erected from both edges of a bottom plate 2, and a grid-shaped partition wall 4 and a partition wall are provided in a space sandwiched between the side walls 3. 5 is arranged.

Here, the outermost partition wall 5 is provided slightly inside from the ends of the bottom plate 2 and the side wall 3 to form a space 6 as a connecting recess surrounded by the bottom plate 2, the side wall 3 and the partition wall 5. ing.

Further, a rubber gasket 8 as a water stopping means is provided around one of the connecting concave portions 6.

The rubber gasket 8 is substantially U-shaped as a whole and protrudes laterally from the ends of the bottom plate 2 and the side wall 3. Two intermediate caissons 1 are provided on the side where the rubber gasket 8 is provided. When connected with the other side,
The bottom plates 2 and the side walls 3 are brought into close contact with each other via a rubber gasket 8, and external water is supplied to the inner connection recess 6.
So that it does not penetrate

A sheath tube 7 through which a PC steel wire is inserted is embedded in the partition wall 4.

FIG. 2 shows an end caisson 11 as a breakwater caisson according to the present embodiment in a plan view and a cross-sectional view along the line CC.

The end caisson 11 also has two side walls 3 erected from both edges of the bottom plate 2 as in the case of the intermediate caisson 1, and a grid-shaped partition wall 4 and a partition wall 5 are arranged in a space sandwiched between the side walls 3. It is.

The outermost partition wall 5 is provided slightly inside from the ends of the bottom plate 2 and the side wall 3, and has a space 13 as a connecting recess at one end and a space 12 for fixing a PC steel material at the other end. I have.

A rubber gasket 14 is provided around the coupling recess 13 as a water stopping means.

The rubber gasket 14, like the rubber gasket 8, is substantially U-shaped as a whole and protrudes laterally from the ends of the bottom plate 2 and the side wall 3, and the end caisson 11 provided with the rubber gasket 14 is provided. Is connected to the side of the intermediate caisson 1 where the rubber gasket 8 is not provided, the bottom plates 2 and the side walls 3 are connected to the rubber gasket 14.
, So that external water does not enter into the inner connection concave portions 6 and 13.

A sheath tube 7 through which a PC steel wire is inserted is embedded in the partition wall 4.

Next, a procedure for constructing a breakwater by connecting the intermediate caisson 1 and the end caissons 11 and 11 of this embodiment to each other will be described below with reference to the flowchart shown in FIG.

First, as shown in FIG.
Is disposed in the vicinity of the end caisson 11 previously installed on the rubble 22 laid on the sea floor, and the connection recess 13 formed at one end of the end caisson 11 and the connection formed at one end of the intermediate caisson 1. (Step 10)
1).

In order to prevent the rubble 22 from being caught between the end caisson 11 and the intermediate caisson 1 in a drawing operation to be described later, a slab 23 such as a precast board is laid in advance as shown in FIG. Is good.

Next, as shown in FIG.
End caisson 1 pre-installed using a winch etc.
1 and the rubber gasket 14 is made adjacent to the corresponding position of the intermediate caisson 1 (step 102).

In this state, the connecting recess 13 and the connecting recess 6 form an integrated space, in which seawater 21 is present.

It is preferable that the bottom plate 2 of the intermediate caisson 1 be appropriately brought into contact with the bottom plate 23 by appropriately pouring water into the intermediate caisson 1 to avoid damage to the rubber gasket 14 due to collision with the end caisson 11. .

Next, as shown in FIG. 6, the seawater 21 collected in the connecting recess 13 and the connecting recess 6 is drained while preventing water from entering by the rubber gasket 14 (step 1).
03).

As the seawater 21 is drawn out, the water pressure in the sea acts in the direction of bringing the end caisson 11 and the intermediate caisson 1 into close contact with each other, as indicated by the arrow in FIG. 14 deforms as shown in FIG. 6 and almost completely blocks intrusion of water from the outside.

After completely draining the inside of the connecting recess 13 and the connecting recess 6 in this manner, as shown in FIG.
In the same procedure as described above, another end caisson 11 is arranged near the intermediate caisson 1, and the end caisson 11 and the intermediate caisson 1 are brought into close contact with each other (step 104).

Next, as shown in FIG. 8, a PC steel wire 31 as a PC steel material is inserted into the sheath tube 7 and the coupling 3 is inserted into the coupling concave portions 13 and 6.
2 (step 105).

Next, a prestress is introduced into the PC steel wire 31 by installing a hydraulic jack in the PC steel wire fixing space 12 and driving a hydraulic pump disposed in the vicinity thereof (step 106).

Finally, using the fixing device 33, the PC steel wire 31 is used.
Is fixed in the PC steel wire fixing space 12, cement grout is injected into the sheath pipe 7, the rust prevention is applied to the PC steel wire 31, and the adhesion between the PC steel wire and the concrete is secured (step 107). .

In FIG. 8, a pair of end caisson 1
Although the state where only one intermediate caisson 1 is interposed between 1 and 11 is shown, the number of such intermediate caissons 1 may be appropriately increased according to a desired caisson length.

Thus, the end caissons 11 and 11 and the predetermined number of intermediate caissons 1 are connected and integrated to construct a long caisson of a desired length.

As described above, in the method of connecting the breakwater caisson and the breakwater caisson of the present embodiment, the connecting recesses are provided at opposing positions of the pair of end caissons and the intermediate caisson sandwiched therebetween. After the end caisson and the intermediate caisson are adjacent to each other via the predetermined water stopping means in the connection recess, by removing water accumulated in the connection recess while preventing external water from entering by the water stopping means. The end caisson and the intermediate caisson are brought into close contact with each other, and a prestress is introduced by inserting the PC steel wire into the through hole for the PC steel wire, and then both ends of the PC steel wire are connected to the opposite end of the end caisson. Since it is fixed to the provided PC steel wire fixing space, at the connection portion, a structure capable of transmitting axial force, shear force and bending moment, particularly,
The structure becomes strong against the bending moment in the horizontal plane due to the wave force or the bending moment in the vertical plane due to the differential settlement, and a desired number of breakwater caissons can be connected for integration.

That is, even if the scale of the caisson is a realistic size in consideration of production, towing and the like, for example, about 20 m in length, the caisson is connected to integrate the It is possible to construct a 100 m long caisson.

Therefore, smoothing of the wave pressure is introduced at the design stage of the caisson, so that the design load can be reduced as compared with the conventional case, and the cross-sectional dimension can be greatly reduced.

In this embodiment, the PC steel wires are joined to each other in the connecting recess. However, such intermediate joining may be omitted by using a PC steel wire having a length corresponding to the entire length of the caisson. .

In the present embodiment, a PC steel wire is used as the PC steel material, but a PC steel stranded wire or the like may be used instead.

[0056]

As described above, the breakwater caisson of the present invention has the predetermined connecting recesses formed at both ends and the through holes for PC steel penetrating from one end to the other. It is possible to increase the size while avoiding problems during production or transportation.

Further, the caisson for breakwater of the present invention has a predetermined connecting recess at one end, a space for fixing PC steel at the other end, and a penetrating PC steel material penetrating from one end to the other. Since the holes are provided, the size can be increased while avoiding problems during production or transportation.

The caisson structure for a breakwater of the present invention
A pair of end caissons having a predetermined connecting recess formed at one end, a PC steel fixing space formed at the other end, and a PC steel through hole penetrating from one end to the other of the end are provided. Are arranged to face each other and the PC
Since the steel material is inserted into the PC steel material through-hole and fixed in the PC steel material fixing space, the size can be increased while avoiding problems during production or transportation.

The caisson structure for a breakwater of the present invention
A pair of end caissons having a predetermined connecting recess formed at one end, a space for fixing the PC steel at the other end, and a through hole for the PC steel penetrating from one end to the other of the end; An intermediate caisson provided with a PC steel material through-hole formed at both ends and penetrating from one end of the end to the other is opposed to the connecting concave portion of the end caisson and the connecting concave portion of the intermediate caisson. So that
Since a predetermined PC steel material is inserted into the PC steel material through-hole of the end caisson and the PC steel material through-hole of the intermediate caisson and is fixed in the PC steel material fixing space, problems during production or transportation can be avoided. In addition, the length can be increased.

Further, in the method of connecting a breakwater caisson according to the present invention, a plurality of breakwater caissons provided with through holes for PC steel are connected to the connecting recess formed at at least one end of each breakwater caisson. Arranging the breakwater caisson via predetermined water stopping means, and draining water accumulated in the connection recess while preventing water from entering from outside by the water stopping means. When,
A step of inserting a predetermined PC steel material into the PC steel material through hole, a step of introducing a prestress into the PC steel material, and a step of applying the PC steel material to two ends of the plurality of breakwater caissons arranged at both ends. Fixing in the PC steel material fixing space formed in the part caisson, and injecting cement grout into the PC steel material through hole.
It is possible to increase the size while avoiding problems during production or transportation.

[0061]

[Brief description of the drawings]

FIG. 1A is a plan view of an intermediate caisson according to the present embodiment,
(b) is a side view along line AA of (a), (c) is BB of (a)
Sectional view along the line.

FIG. 2A is a plan view of an end caisson according to the present embodiment,
(b) is a side view along the line CC of (a).

FIG. 3 is a flowchart illustrating a procedure of a method of connecting a breakwater caisson according to the present embodiment.

FIG. 4 (a) is a plan view showing a state in which an end caisson and an intermediate caisson are arranged such that connection concave portions face each other;
(b) is sectional drawing which follows the DD line of (a).

5A is a plan view showing a state in which an intermediate caisson is drawn to and adjacent to an end caisson, and FIG. 5B is a cross-sectional view taken along line EE in FIG. 5A.

FIG. 6 (a) is a plan view showing a state in which water accumulated in a connecting recess is drained and an intermediate caisson is brought into close contact with an end caisson;
(b) is a sectional view taken along line FF of (a).

FIG. 7 (a) is a plan view showing a state in which an intermediate caisson is sandwiched between a pair of end caissons and closely attached to each other, and FIG.
Sectional drawing along G line.

FIG. 8A is a plan view showing a state in which an intermediate caisson is sandwiched between a pair of end caissons and connected by a PC steel wire, and FIG.
3A is a cross-sectional view along the line HH in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Breakwater caisson (intermediate caisson) 6, 13 Connecting recess 7 PC steel wire sheath tube (PC steel through hole) 8 Rubber gasket (water stopping means) 11 Breakwater caisson (end caisson) 12 PC steel wire anchoring Space for PC steel fixing space 31 PC steel wire (PC steel) 32 Coupling 33 Fixing tool 101 Arrangement process 102 Adjacent process 103 Adhesion process 105 PC steel wire insertion process 106 Prestress introduction process 107 PC steel wire fixing process

Claims (6)

(57) [Claims] 1. A caisson for a breakwater, wherein a predetermined concave portion for connection is formed at both ends, and a through hole for a PC steel penetrating from one of the ends to the other is provided. 2. A PC steel material fixing space is formed at one end, a PC steel material fixing space is formed at the other end, and a PC steel material through hole penetrating from one end to the other end is provided. Breakwater caisson. 3. The breakwater caisson according to claim 1, wherein a predetermined water stopping means is provided around the connection recess. 4. A pair of end caissons having a predetermined connecting recess formed at one end, a space for fixing a PC steel material formed at the other end, and a through hole for a PC steel material penetrating from one end to the other end. A caisson structure for a breakwater, wherein a predetermined PC steel material is inserted through the through hole for the PC steel material and is fixed in the space for fixing the PC steel material. 5. A pair of end caissons having a predetermined connecting recess at one end, a space for fixing a PC steel at the other end, and a through hole for a PC steel penetrating from one end to the other of the ends. And an intermediate caisson formed with a predetermined connecting recess at both ends and having a through hole for PC steel penetrating from one end to the other of the end, and connecting the connecting recess of the end caisson and the intermediate caisson. It is arranged so that the recessed part faces, and a predetermined PC steel material is
A caisson structure for a breakwater, wherein the caisson structure for a breakwater is inserted into a through hole for a C steel material and a through hole for a PC steel material of the intermediate caisson and fixed in the PC steel material fixing space. 6. A step of arranging a plurality of breakwater caissons provided with through holes for PC steel so that connection concave portions formed at least at one end of each breakwater caisson are opposed to each other. A step of adjoining via a predetermined water stopping means, while preventing water from entering from outside by the water stopping means,
A step of draining water accumulated in the connecting recess; a step of inserting a predetermined PC steel into the PC steel through-hole; a step of introducing prestress into the PC steel; and a step of applying the PC steel to the plurality of breakwaters. For caisson
PC formed in two end caissons arranged at both ends
A step of injecting cement grout into the through hole for PC steel while fixing the steel in the steel material fixing space, and connecting the caisson for breakwater.