JP3993430B2 - Pneumatic caisson and caisson construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a caisson and a caisson construction method by a pneumatic caisson method used for a shaft or a bridge foundation used as an underground structure.
[0002]
[Prior art]
An example of a conventional pneumatic caisson is shown in FIG. That is, in FIG. 11, the pneumatic caisson 1 is provided with a caisson housing 2 on the upper side of the work chamber slab 3, and on the lower side of the work chamber slab 3, a work chamber 4 surrounded by a blade 3 a and a natural ground G. Is provided. Inside the caisson housing 2, a man shaft 5 on which the worker moves up and down is provided above the work chamber 4, and a man lock 6 through which the worker enters and exits is provided above the man shaft 5. . Further, a material shaft 7 is provided separately from the man shaft 5, and a material lock 8 is provided on the upper portion of the material shaft 7. The excavated soil excavated from the natural ground G in the work chamber 4 from the material shaft 7 is carried out by the bucket 7a, and materials and equipment are carried in and out.
[0003]
The caisson housing 2 is generally formed by stacking reinforced concrete lots 2a, and the length per lot is about 4 m.
[0004]
[Problems to be solved by the invention]
However, in the conventional pneumatic caisson construction method, it is necessary to perform the following steps in order to construct the caisson housing 2.
[0005]
(1) Assembly of scaffold, (2) Reinforcement assembly, (3) Formwork assembly, (4) Concrete placement, (5) Curing, (6) Latency treatment, (7) Formwork dismantling, (8) Scaffolding Change The above work was a high place work, and it was necessary to assemble rebars and formwork to about 4 m or more, and it took time to assemble the rebar and form and disassemble the formwork. In addition, since the subsidence excavation of each lot 2a cannot be performed until the construction of each lot 2a of the caisson housing 2 is completed, a waiting time is generated, so that the mechanical equipment is idle and power is wasted, and the mechanical equipment loss There was waste.
[0006]
In addition, when the natural ground G is soft ground, the work room 4 may be crushed by the dead weight of the caisson frame 2 made of reinforced concrete and the work room 4 may be crushed. And ground improvement work is required, and there is a problem that it takes work time and cost.
[0007]
Therefore, the present invention has been made in view of the above points, and reduces the work at high places and assembly / disassembly work at the site, does not require much waiting time before performing subsidence excavation work, and is soft. It is an object to provide a pneumatic caisson and a caisson construction method that do not require ground replacement or ground improvement.
[0008]
[Means for Solving the Problems]
To achieve the foregoing object, the invention according to claim 1, in pneumatic caisson having a working chamber slab having a working chamber on the lower side, and a caisson precursor provided on the upper side of the working chamber slab, the A working chamber slab and the caisson housing are anchored, and the caisson housing has a plurality of steel tubular bodies arranged continuously in an annular shape, and a pair of connecting pieces between the tubular bodies. an annular member that is coupled by a connecting member consisting of an outer wall plate covering between each other the tubular body adjacent is attached to the outer periphery of the annular body, the inner space of the tubular member or the inner, A pneumatic caisson in which a space and a space between the outer wall plate and the cylindrical body are filled with a filler is provided.
[0009]
The invention according to claim 2 is characterized in that, in addition to the configuration according to claim 1, an inner wall plate that covers the space between the cylindrical bodies is attached to the inner periphery of the annular body. .
The invention described in claim 3 is characterized in that, in addition to the configuration described in claim 2, a space between the inner wall plate and the cylindrical body is filled with a filler .
[0010]
In addition to the structure in any one of Claims 1 thru | or 3 , the invention of Claim 4 is characterized by the said cylindrical body being a single body or a some cylindrical member.
[0011]
According to a fifth aspect of the present invention, in the method for constructing a caisson by a pneumatic caisson method, a plurality of cylindrical bodies are continuously arranged in an annular shape, and a pair of connecting pieces are provided between the plurality of cylindrical bodies. A caisson housing is formed on the upper side of the working chamber slab, in which an annular body connected by a connecting tool is formed, and an outer wall plate that covers between the adjacent cylindrical bodies is attached to the outer periphery of the annular body. The caisson housing construction process, the subsidence excavation process for sinking the upper end of the caisson housing to near the ground surface by the subsidence excavation method, and the upper ends of the plurality of cylindrical bodies and the lower ends of the upper cylindrical bodies are connected. A caisson housing connecting step of stopping water by surrounding the adjacent upper cylindrical bodies with an outer wall plate, and a caisson construction method for repeating the subsidence excavation step and the caisson housing connecting step. Characterized by
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described based on embodiments.
[0016]
Embodiment 1 of the Invention
1 to 6 show a first embodiment of the present invention.
[0017]
1 is a cross-sectional view of a caisson according to Embodiment 1 of the present invention.
[0018]
First, the configuration will be described. Reference numeral 20 in the figure denotes a caisson, and the caisson 20 is provided with a caisson housing 21 composed of a cylindrical tubular body 21 a on the upper side of the work chamber slab 23. A work chamber 25 surrounded by a blade edge 23a and a natural ground G is provided below the work chamber slab 23. Inside the caisson housing 21, a man shaft 26 on which a worker moves up and down is provided above the work chamber 25, and a man lock 27 on which the worker enters and exits is provided above the man shaft 26. . Further, a material shaft 28 is provided separately from the man shaft 26, and a material lock 29 is provided on the upper portion of the material shaft 28.
[0019]
The working chamber slab 23 and the cylindrical body 21a constituting the caisson housing 21 are connected by a connecting portion 30. FIG. 2 shows a cross-sectional view and a plan view of the connecting portion 30. As shown in FIG. 2, an anchor steel frame 31 is embedded in the work chamber slab 23, and a fixing steel frame 32 is attached to the bottom of the cylindrical body 21a. A cylindrical body 21a is arranged so as to cover the anchor steel frame 31 embedded in the working chamber slab 23, and the anchor steel frame 31 and the fixing steel frame 32 are fixed by a filler 33 such as concrete in the cylindrical body internal space 22.
[0020]
3 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 4 is an enlarged view of a connecting portion between the cylindrical bodies 21a.
[0021]
As shown in FIGS. 3 and 4, the inside of the cylindrical body 21 a is hollow, a plurality of cylindrical bodies 21 a are arranged in an annular shape, and the cylindrical bodies 21 a are connected to each other by a connector 35. A filler 36 such as mortar is injected into the space of the connector generated by the shape of the connector 35 to stop water.
[0022]
In the first embodiment, the cylindrical body 21a is connected by the connecting tool 35. However, the connecting means is not limited to the method using the connecting tool 35, and means such as welding or a bolt and nut may be used.
[0023]
An outer wall plate 37 made of a steel plate or the like is provided on the outer periphery of the annular body formed by the plurality of cylindrical bodies 21a in order to smooth the outer peripheral surface, to increase rigidity, or to achieve perfect water stoppage. Is attached. The outer wall plate 37 may not be attached when the surrounding ground is hard or when it is not necessary as a water stop means.
[0024]
Next, an operation process for constructing the caisson 20 will be described.
[0025]
First, the working chamber slab 23 is constructed, the anchor steel frame 31 is embedded on the periphery of the upper surface of the working chamber slab 23, and a plurality of cylindrical bodies 21 a are arranged so as to cover the anchor steel frame 31. Then, a filler 33 such as concrete is placed in the cylindrical body internal space 22 of the cylindrical body 21 a to fix the anchor steel frame 31 and the fixing steel frame 32, and the connection portion 30 between the cylindrical body 21 a and the working chamber slab 23. Form.
[0026]
Next, the adjacent cylindrical bodies 21a are connected to each other with a connecting tool 35, and the periphery of the plurality of cylindrical bodies 21a connected in an annular shape is covered with an outer wall plate 37. When the surrounding earth pressure or water pressure is high, or when the water stop effect is enhanced, the space 38 between the outer wall plate 37 and the cylindrical body 21a may be filled with a filler. As the filler, non-shrinkable fillers such as sand, crushed stone, foamed mortar, cement bentonite, non-shrinkable mortar and concrete can be used.
[0027]
When the subsidence load is insufficient or the strength of the cylindrical body 21a is insufficient, the cylindrical body internal space 22 is filled with crushed stone, sand, earth and sand, concrete or the like, or a reinforcing bar is disposed.
[0028]
Next, the natural ground G is excavated by the subsidence excavation method of the normal pneumatic caisson method, and the caisson 20 is subsidized.
[0029]
Although the earth pressure and the water pressure increase as the caisson 20 sinks, in order to prevent the cylindrical body 21a from being deformed, the earth retaining material 40 is installed as necessary, or the caisson 20 is attached to the bridge. When used as a foundation, the inner space 42 of the caisson housing 21 may be filled with a filling material 41 such as excavated soil, mountain sand crushed stone, and fluidized soil.
[0030]
When the caisson 20 sinks and the upper end of the cylindrical body 21a approaches the ground surface 43, the upper end of the cylindrical body 21a and the lower end of the upper cylindrical body 21a are connected by welding or the like to form a connection location 44. . Further, the adjacent cylindrical bodies 21a for the upper stage are connected in the same manner as the lower stage, and the water is stopped by the water stopping means.
[0031]
In addition, the connection method of the connection location 44 can consider the method of joining the meshing formed previously other than welding.
[0032]
In the first embodiment, as a water stop means, a method of injecting a filler 36 such as mortar into the space of the connector or enclosing it with an outer wall plate 37 is used. However, the outer wall plate 37 and the cylindrical body 21a A method of filling the space 38 with a filler is also conceivable.
[0033]
The caisson 20 is sunk to a predetermined depth by repeating the sinking excavation process and the connecting process of the cylindrical body 21a forming the caisson housing 21.
[0034]
FIG. 5 shows a plan view of caisson housing 21 of Modification 1 according to Embodiment 1 of the present invention.
[0035]
In this modification 1, the inner wall board 50, such as a steel plate, is installed in the inner periphery of the cylindrical body 21a arrange | positioned circularly without using the earth retaining material 40, and the cylindrical body 21a and an outer wall board are used as a water stop means. The space 38 surrounded by 37 and the space 51 surrounded by the cylindrical body 21a and the inner wall plate 50 are filled with a filler such as concrete. Packing the filler also serves as a reinforcing means for the caisson housing 21.
[0036]
In FIG. 6, the top view of the caisson housing 21 of the modification 2 which concerns on Embodiment 1 of this invention is shown.
[0037]
In this modified example 2, the cylindrical body 21a is surrounded by a plate 60 such as a steel plate every several to form an integrated cylindrical body 61, and the integrated cylindrical bodies 61 are annularly arranged and connected. Furthermore, the outer wall plate 37 and the inner wall plate 50 surround the outer side and the inner side of the connecting portion between the integrated cylindrical bodies 61, respectively. In this modified example 2, as a water stop means, a space 38 surrounded by the cylindrical body 21a and the outer wall plate 37 and a space 51 surrounded by the cylindrical body 21a and the inner wall plate 50 are filled with a filler such as concrete. Have taken. This filler also serves as a reinforcing means for the caisson housing 21. According to this method, the caisson housing 21 having a high water stop effect and strength can be formed.
[0038]
By adopting the caisson 20 construction method as described above, the construction work of the caisson housing 21 is only the connection of the adjacent cylindrical bodies 21a and the connection work of the upper and lower cylindrical bodies 21a. That is, it is not necessary to perform assembly / disassembly work of rebars and formwork as in the prior art, and there is no waiting time for curing the concrete, so the work amount and cost can be greatly reduced. Moreover, the frequency | count of connecting the cylindrical body 21a can also be reduced by making the length of the cylindrical body 21a longer than the length of the conventional lot 2a.
[0039]
Furthermore, since the inside of the cylindrical body 21a is hollow, the weight of the caisson 20 is reduced and it is difficult for the caisson 20 to sink naturally, so that it is not necessary to replace the ground with soft ground or improve the ground.
[0040]
Furthermore, by adjusting the amount of the filler that fills the cylindrical body internal space 22, it is possible to change the dead weight of the cylindrical body 21a to adjust the sinking load, and to increase or decrease the strength of the cylindrical body 21a. Therefore, it becomes possible to cope with ground of various firmness.
[0041]
[Embodiment 2 of the Invention]
7 and 8 show a second embodiment of the present invention.
[0042]
FIG. 7 is a plan view of the caisson housing 21 according to Embodiment 2 of the present invention, and FIG. 8 is an enlarged view of a connecting portion between the rectangular tubular bodies 21b. Further, the cross-sectional view according to the second embodiment is the same as FIG. 1 in the first embodiment.
[0043]
In the first embodiment, the cylindrical tubular body 21a is used as the caisson housing 21, but in the second embodiment, a rectangular tubular body 21b is used.
[0044]
An annular body is formed by arranging and connecting a plurality of rectangular cylindrical bodies 21b in an annular shape. As in Embodiment 1, an outer wall plate 37 for smoothing the outer peripheral surface of the annular body is provided. Since it is not necessary to use the entire outer peripheral surface, the amount of the outer wall plate 37 used can be reduced. In addition, since the volume of the space 38 surrounded by the outer wall plate 37 and the cylindrical body 21b is reduced, the amount of the filler can be reduced when the space 38 is filled with the filler. Further, the caisson housing 21 constructed with the rectangular tubular body 21b can obtain a greater strength than that constructed with the cylindrical tubular body 21a. However, the quadrangular cylindrical body 21b has a drawback that it is expensive because it needs to be ordered and manufactured by a special order from a supplier.
[0045]
Other configurations, operations, and effects are the same as those of the first embodiment, and thus redundant description is omitted.
[0046]
Embodiment 3 of the Invention
9 and 10 show a third embodiment of the present invention.
[0047]
FIG. 9 is a plan view of the caisson casing 21 according to Embodiment 3 of the present invention, and FIG. 10 is an enlarged view of a connecting portion between the rectangular cylindrical bodies 21b.
[0048]
In the third embodiment of the present invention, the rectangular cylindrical bodies 21b are arranged vertically and horizontally to form four inner spaces 42 of the caisson casing 21, and the caisson casing 21 of the third embodiment of the present invention is Suitable for large-scale structures.
[0049]
Other configurations, operations, and effects are the same as those of the second embodiment of the present invention, and thus redundant description is omitted.
[0050]
In the third embodiment of the present invention, the rectangular tubular body 21b is used, but a cylindrical tubular body 21a may be used. Further, in Embodiment 3 of the present invention, the annular shape of the caisson housing 21 is constructed in a square shape, but is not limited to the shape, and may be a rectangle, a rhombus or the like as long as it has a circular water-stopping shape.
[0064]
In each of the above-described embodiments, the method of assembling the caisson housings 21 in stages and connecting them in a plurality of stages has been adopted in the field. However, the present invention is not limited to this method. A caisson construction method may be adopted in which a plurality of stages of caisson housings 21 for one stage are added on the site.
[0065]
【The invention's effect】
As described above, according to the first aspect of the present invention, in the caisson having the work chamber slab having the work chamber on the lower side and the caisson housing provided on the upper side of the work chamber slab, the caisson housing is provided. Has an annular body in which a plurality of cylindrical bodies are arranged in an annular shape, and an outer wall plate covering between the adjacent cylindrical bodies is attached to the outer periphery of the annular body. The time and cost of caisson construction work can be reduced, and the weight of the caisson can be adjusted, making it difficult for natural settlement to occur, eliminating the need for ground replacement and ground improvement on soft ground. Further, there is no gap on the outer peripheral surface of the caisson housing, and it is possible to maintain complete water stoppage without filling concrete between the tubular bodies and to increase the rigidity of the entire caisson housing.
[0066]
According to the second aspect of the present invention, in addition to the effect of the first aspect, the inner space of the cylindrical body can be filled with an arbitrary amount of filler. A caisson can be constructed by using the cylindrical body of the present invention corresponding to the ground subjected to hardness and water pressure.
[0067]
According to the invention described in claim 3, in addition to the effect described in claim 1 or 2, the cylindrical body is a single member or a plurality of cylindrical members. Can be built.
[0068]
According to the fourth aspect of the present invention, in the method for constructing a caisson by the pneumatic caisson method, the annular body has an annular body in which a plurality of cylindrical bodies are annularly arranged, and is adjacent to the outer periphery of the annular body. A caisson housing construction process for constructing a caisson housing to which an outer wall plate covering between the cylindrical bodies is attached on the upper side of the work room slab, and a settlement for sinking the upper end of the caisson housing to near the ground surface by a subsidence excavation method. A caisson that connects the excavation stroke and the upper ends of the plurality of cylindrical bodies and the lower ends of the upper cylindrical bodies, and surrounds the adjacent upper cylindrical bodies with an outer wall plate to stop water. The caisson housing is constructed by repeating the subsidence excavation process and the caisson housing connecting process, and the construction work of the caisson housing is performed by connecting the adjacent tubular bodies and the upper and lower tubular bodies. Connection work between each other Mitonari, it is not necessary to perform the assembling disassembling operations of a conventional reinforcing bar assembly and mold-scaffolds, such as, for latency or the like for curing the concrete does not occur, can be reduced significantly working stroke and cost. Moreover, the frequency | count of connecting a cylindrical body can also be reduced by making the length of a cylindrical body longer than the length of the conventional lot.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a caisson according to Embodiment 1 of the present invention.
FIGS. 2A and 2B are a cross-sectional view and a plan view of a connecting portion between a cylindrical body and a working chamber slab according to the first embodiment.
3 is a cross-sectional view taken along line AA in FIG. 1 according to the first embodiment. FIG.
4 is an enlarged view of a connecting portion between cylindrical cylindrical bodies according to the first embodiment. FIG.
FIG. 5 is a plan view of a caisson housing of a first modification according to the first embodiment.
FIG. 6 is a plan view of a caisson housing of a second modification according to the first embodiment.
FIG. 7 is a plan view of a caisson housing according to a second embodiment of the present invention.
FIG. 8 is an enlarged view of a connecting portion of the rectangular tubular bodies according to the second embodiment.
FIG. 9 is a plan view of a caisson housing according to a third embodiment of the present invention.
FIG. 10 is an enlarged view of a connecting portion of rectangular tubular bodies according to the third embodiment.
FIG. 11 is a cross-sectional view of a conventional caisson.
[Explanation of symbols]
20 Pneumatic caisson 21 Caisson housing 21a Cylindrical tubular body 21b Square tubular body 22 Cylindrical internal space 23 Work chamber slab 25 Work chamber
33 Filling material (water stop means)
35 Connector 36 Filling material (water stop means)
37 Outer wall plate (water stop means)
38 Space between outer wall plate and cylindrical body
50 Inner wall plate (water stop means)
51 Space between inner wall plate and cylindrical body

Claims (5)

In a pneumatic caisson having a work room slab having a work room on the lower side and a caisson housing provided on the upper side of the work room slab,
The working chamber slab and the caisson housing are anchor-connected, and the caisson housing includes a plurality of steel tubular bodies arranged continuously in an annular shape, and a pair of links between the plurality of tubular bodies. An annular body connected by a connecting member made of a piece, and an outer wall plate covering between the adjacent cylindrical bodies is attached to the outer periphery of the annular body, and the internal space of the cylindrical body or the A pneumatic caisson characterized in that an internal space and a space between the outer wall plate and the cylindrical body are filled with a filler . 2. The pneumatic caisson according to claim 1 , wherein an inner wall plate that covers a space between the cylindrical bodies is attached to an inner periphery of the annular body . The pneumatic caisson according to claim 2 , wherein a filler is filled in a space between the inner wall plate and the cylindrical body . The pneumatic caisson according to any one of claims 1 to 3, wherein the tubular body is a single body or a plurality of tubular members . In the method of building a caisson with the pneumatic caisson method,
A plurality of cylindrical bodies are continuously arranged in an annular shape, and an annular body is formed that is connected between the plurality of cylindrical bodies with a connector composed of a pair of connecting pieces. A caisson housing construction process for constructing a caisson housing to which an outer wall plate covering between adjacent cylindrical bodies is attached on the upper side of the work room slab, and the upper end of the caisson housing is submerged to the ground surface by a subsidence excavation method The subsidence excavation process is connected to the upper ends of the plurality of cylindrical bodies and the lower ends of the upper cylindrical bodies, and the adjacent upper cylindrical bodies are surrounded by an outer wall plate to stop water. A caisson construction method comprising: a caisson housing connection process, and repeating the subsidence excavation process and the caisson housing connection process.

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