JPH1046596A - Form to construct underwater caisson, underwater caisson and construction method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a form, underwater caissons and a construction method therefor by which the respective caissons to constitute an underwater structure can be enlarged and influence of wave power and a tidal current at towing time can be reduced and the caissons can be easily constructed by execution work on the sea. SOLUTION: In a form to construct a caisson to constitute an underwater structure, a bottom surface and side surfaces are formed of a perforated plate, and partition walls 13 which are arranged on an outer periphery of steel frame assemblies 11 and 12 and separate by a prescribed length on the whole inside periphery of the side surfaces, are formed of a perforated plate. An underwater caisson is provided with a form, a hydraulic setting filler 20 filled in a first division surrounded by the bottom surface, the side surfaces and the partition walls 13 in the form and an infilling material 21 filled in a second division surrounded by the bottom surface and the partition walls 13. The underwater caisson is constructed by a process of towing the form, a process of placing the form on the bottom of the water or an underwater footing, a process of filling the infilling material 21 in the second division and a process of filling the hydraulic setting filler in the first division.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a formwork for constructing an underwater structure, an underwater caisson constructed using the formwork, and a method for constructing an underwater caisson.

[0002]

2. Description of the Related Art When constructing an underwater structure using a caisson, a caisson is conventionally formed from reinforced concrete or steel plate at the coastal area, and the caisson is lifted by a crane ship so that the bottom surface does not contact the sea surface. Tow to the installation sea area, or float the caisson on the sea, inject a predetermined amount of water into the caisson to balance the caisson, or place a float etc. around the caisson and tow it to the installation sea area, and tow to the sea floor in advance Sink on the built mound.

[0003]

In the method of constructing an underwater structure using a caisson, in the above case, the size of the caisson is limited by the lifting capacity of the crane ship, and therefore, the caisson is sunk into a deep water. In this case, the caisson has to be formed with a relatively small cross section, so that the number of caissons is increased, the construction work is increased, and the construction cost is increased. For example, the lifting capacity of a crane ship which is considered to have the maximum lifting capacity in Japan at the time of filing of the present application is about 4000 to 5000 tons, and considering the safety of work, the weight of the caisson is 30
The limit is about 00 tons.

On the other hand, the above case has an advantage that a large caisson can be towed as compared with the above case. However, large caisson has a problem that it is easily affected by wave force and tidal current at the time of towing, and large caisson requires deep dock because towing draft is deep and usable dock is not available. There is a problem that it is limited.

The present invention focuses on the drawbacks of the above-mentioned prior art and solves the problem. The purpose of the present invention is to make it possible to increase the size of each caisson constituting an underwater structure, and to reduce the wave force and tidal current during towing. It is an object of the present invention to provide a caisson construction formwork that is not easily affected by the above.

It is another object of the present invention to provide an underwater caisson that enables each caisson constituting an underwater structure to be enlarged and that can be easily constructed by construction on the sea.

Another object of the present invention is to enable each caisson constituting an underwater structure to be enlarged, to reduce the influence of wave force and tidal current during towing, and to facilitate the construction at sea. And a method for constructing an underwater caisson.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and its gist is a formwork for constructing a caisson constituting an underwater structure.
A bottom surface placed on a water bottom or an underwater foundation and a side surface extending from the bottom surface toward the water surface are formed of a perforated plate and provided on the outer periphery of the steel frame assembly. An underwater caisson construction mold characterized in that a separated partition wall is formed by a perforated plate. Here, in the underwater caisson construction form of the present invention, mesh steel, a grating plate, or the like can be used as the perforated plate. Further, in the present invention, the steel frame assembly may be formed so as to be disposed inside the partition wall, and a perforated plate may be provided in the steel frame assembly inside the partition wall so as to be substantially parallel to the partition wall. By providing such a perforated plate, the rigidity of the underwater caisson construction formwork itself can be improved.

[0009] Another aspect of the present invention is to provide an underwater caisson construction mold according to claim 1 and a hydraulic fluid filled in a first compartment surrounded by a bottom surface, a side surface and a partition wall of the mold. An underwater caisson comprising a filler and a filling material filled in a second section surrounded by the bottom surface and the partition. Here, in the underwater caisson of the present invention, a concrete bottom plate having a predetermined thickness may be provided on the bottom surfaces of the first section and the second section.

[0010] Another aspect of the present invention is a steel frame assembly,
The underwater according to claim 1, comprising a bottom surface, a side surface, and a partition wall formed of a perforated plate, a first partition surrounded by the bottom surface, the side surface, and the partition wall, and a second partition surrounded by the bottom surface and the partition wall. Towing the caisson-forming formwork, placing the formwork on the bottom of the water or on an underwater foundation, and filling the second section of the placed formwork with a predetermined amount of filling material. A method for constructing an underwater caisson, comprising: a step of filling a first section of the mold with a hydraulic filler after filling a predetermined amount of the filling material.

Here, in the method of constructing an underwater caisson of the present invention, a step of forming a concrete bottom plate may be added prior to the step of filling the second section with a predetermined amount of filling material. That is, a predetermined length (for example, 1
m), filling both the first section and the second section with a filling material such as stone, and then underwater concrete or the like so as to spread over all the gaps of the input stones. May be filled to form a concrete bottom plate on the bottom surface. By forming the concrete bottom plate in this way, there is an advantage that the installed underwater caisson can be stabilized at an early stage and the gap between the underwater caisson and the underwater caisson bottom plate can be reduced.

In the present invention, the hydraulic filler may be any material that is in a fluid state when it is filled in the first compartment, and is cured after a predetermined time by reacting with water. There is underwater concrete. In the present invention, the filling material has a particle size that does not pass through the hole of the partition wall or the bottom plate, and may be a material having a specific gravity larger than that of water, for example, formed by crushing stone or concrete. There is crushed stone.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the accompanying drawings, but the present invention is not limited to these embodiments. FIG. 1 is a plan view of an underwater caisson of the present invention, FIG. 2 (a) is a plan view of a caisson construction form, and FIG. 2 (b) is a view taken along a dashed line IIb-IIb in FIG. 2 (a). 2 (c) is a cross-sectional view taken along a dashed line IIc-IIc in FIG. 2 (a), and FIGS. 3 (a) to 3 (d) show a method of constructing an underwater caisson of the present invention. It is a simplified diagram for explanation.

In FIG. 2, an underwater caisson construction form 10 of the present invention comprises a column member 11 and a beam member 12 made of steel.
A rectangular bottom plate 15 and a side plate 1 formed of a perforated plate, that is, a mesh steel plate, are formed on the outer periphery of a steel frame assembly formed by
6 is fixed, and a rectangular partition wall 13 made of a mesh steel plate is fixed to the entire inner periphery of the side plate 16 with a predetermined distance therebetween.

The steel frame assembly comprises four column members 11 erected substantially vertically at substantially equal intervals in the direction of dashed line IIb-IIb.
Are arranged at substantially equal intervals in a total of 24 rows of 6 rows, and a plurality of beam members 12 vertically spaced apart by a predetermined length are arranged in four layers so as to connect the column members 11 to each other. 2
The beam member 12 is connected to the column member 11 in a positional relationship as shown in the plan view of FIG. Although not shown in FIGS. 2 (a) to 2 (c), columns made of a steel frame are also provided at intersections between the partitions 13 and the beam members 12 and at intersections between the partitions 13, 13 as necessary. The members are erected and the pillar members are connected by beam members.

The bottom plate 15 is fixed to the surface of the steel frame assembly in contact with the bottom or the underwater foundation by welding or bolts when the form 10 is placed on the bottom or the underwater foundation. Are fixed by welding, bolts, or the like to four side surfaces extending from the bottom plate 15 toward the water surface.
By providing such a bottom plate 15, it is possible to prevent the underwater caisson construction formwork 10 from being distorted due to the unevenness even when the underwater or the underwater foundation has irregularities. The upper surface (bottom plate 1) of the underwater caisson construction formwork 10
No. 5 facing surface), the mesh steel plate is not arranged, and is in an open state. Here, the size of the hole of the mesh steel plate used as the bottom plate 15 and the side plate 16 is the largest possible as long as the aggregate contained in the underwater concrete 20 described below does not pass through, so that waves, tides and wind To reduce resistance.

Further, the partition 13 has its lower side and side sides abutted so as not to form a gap between the bottom plate 15 and the surface of the side plate 16 so as to be substantially horizontal with each side plate 16 in four directions by a predetermined length. The bottom plate 15 and the side plate 16 are spaced apart from each other.
(The section indicated by oblique lines in FIG. 2A). Inside the first section 14 thus arranged, a second section 17 surrounded by the partition 13 and the bottom plate 15 is formed.

The underwater caisson construction form 1 of the present invention.
At 0, a mesh steel plate extending in a vertical direction (a direction substantially parallel to the partition 13) may be fixed as the reinforcing plate 18 to the column member 11 and the beam member 12 arranged in the second section 17, By providing the reinforcing plate 18 as described above, the rigidity of the underwater caisson construction formwork 10 is improved, and the underwater caisson construction formwork 10 is used for towing work and submerging underwater.
Can be prevented from being distorted.

The underwater caisson of the present invention comprises the above-described underwater caisson construction form 10, underwater concrete 20 as a hydraulic filler filled in the first section 14, and filling in the second section 17. Stone 21 as a filling material
And

Here, the stone 21 is kept in the second section until the stone 21 reaches a weight enough to sufficiently oppose these external forces even when waves, tides and winds act on the underwater caisson at the time of construction and completion at sea. Fill 17 The underwater concrete 20 is provided on the beam member 12 located at the upper end of the first section 14.
Until it reaches.

Next, a method of constructing an underwater caisson will be described with reference to FIG. First, the underwater caisson construction formwork 10 is manufactured at the shore 35. Next, the underwater caisson construction form 10 is lifted by the crane ship 30 and suspended in seawater, and as shown in FIG. 3 (b), the underwater caisson construction form 10 is submerged to a predetermined depth.
In this flooded state, the underwater caisson construction formwork 10 is towed to the construction sea area. When the crane ship 30 arrives in the construction sea area, the crane ship 30 is placed on the seabed mound 36 constructed in advance on the seabed,
The underwater caisson construction formwork 10 is hung down and placed.

After placing the formwork, the workboat 38 transports the stone as the filling material to the construction sea area, and as shown in FIG. Second section 1
Put in 7. When the second section 17 is filled with a predetermined amount of stones 21 and then the first section 14 is filled with underwater concrete 20 as hydraulic filling, the underwater caisson of the present invention can be constructed.

In the method of constructing an underwater caisson according to the present invention, a step of forming a concrete bottom plate may be added prior to the step of putting a stone into the second section 17. That is, the stone is put into both the first section 14 and the second section 17 until the height reaches about 1 m from the bottom plate 15, and then the underwater is spread so as to reach the gaps between all the put stones. Filling the concrete,
A concrete bottom plate may be formed on the bottom plate 15.

[0024]

According to the present invention, each caisson constituting an underwater structure can be made larger than before.
That is, in the present invention, instead of towing a concrete caisson previously formed in the coastal area as in the related art, an underwater caisson construction form formed mainly with a steel frame assembly and a perforated plate is towed to the caisson installation sea area. Then, after being placed on the bottom of the water or on an underwater foundation, a hydraulic filler or filling material is filled in the underwater caisson construction formwork to construct an underwater caisson. Therefore, if the underwater caisson construction form of the present invention is formed with the same weight as the conventional concrete caisson previously formed in the coastal area, it becomes possible to make the caisson larger than the conventional caisson, and moreover, the same as the conventional caisson It can be towed by a crane ship with lifting capacity.

In the present invention, since the underwater caisson construction formwork is formed by mainly using the steel frame assembly and the perforated plate, when the underwater caisson is constructed in the underwater caisson installation sea area by towing it, waves, Tidal current and wind pass through the perforated plate. Therefore, the shaking of the underwater caisson construction form due to waves, tides, and wind can be reduced, and the safety of work during towing or offshore construction can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of an underwater caisson of the present invention.

FIG. 2 (a) is a plan view of a caisson construction formwork, and FIG.
Is a cross-sectional view taken along dashed line IIb-IIb in (a),
(c) is a cross-sectional view along the dashed-dotted line IIc-IIc in (a).

FIGS. 3A to 3D are simplified diagrams for explaining the underwater caisson construction method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Formwork 11 Steel frame assembly 12 Steel frame assembly 13 Partition wall 14 First section 15 Bottom 16 Side 17 Second section 21 Middle filling material

Claims (3)

[Claims] 1. A formwork for constructing a caisson constituting an underwater structure, the formwork comprising a bottom surface mounted on a water bottom or an underwater foundation, and a side surface extending from the bottom surface toward the water surface. An underwater caisson construction form, comprising: a perforated plate; and a partition wall provided on the outer periphery of the steel frame assembly and provided on the entire inner periphery of the side surface and separated by a predetermined length by a perforated plate. 2. The underwater caisson construction formwork according to claim 1, a hydraulic filler filled in a first section surrounded by a bottom surface, side surfaces and partition walls of the formwork, and the bottom surface. An underwater caisson comprising: a filling material filled in a second compartment surrounded by a partition wall; 3. A steel frame assembly, a bottom surface formed of a perforated plate,
2. The underwater caisson construction form according to claim 1, comprising a side surface and a partition wall, a bottom surface, a first partition surrounded by the side surface and the partition wall, and a second partition surrounded by the bottom surface and the partition wall. Performing the step of placing the form on a water bottom or an underwater foundation; filling the second section of the placed form with a predetermined amount of filling material; Filling the first section of the form with a hydraulic filler after filling with the filler.