JP3760010B2 - Arch culvert construction method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an arch culvert construction technique that is buried in the ground and used for applications such as waterways.
[0002]
[Prior art]
An arch culvert is a concrete pipe with an arched upper section. Conventionally, this type of arch culvert is constructed by laying a base concrete on the ground and then assembling a formwork on it. It is constructed by placing concrete in this formwork. Also, since the arch culvert needs to be waterproofed against the surrounding ground, when the cast concrete hardens and exhibits the specified strength, the formwork is dismantled and removed, and this concrete (arch-shaped concrete) Assemble a temporary scaffold for waterproofing work on the outside of the arch, and use this scaffold to lay and fix a waterproof sheet on the outer peripheral surface of the arch-shaped concrete, or to apply waterproof work by covering with asphalt or the like . When the waterproofing work is finished, the temporary scaffold is removed, and a soil material is backfilled or raised on the arched concrete.
[0003]
[Problems to be solved by the invention]
According to the above conventional method, the following problems are pointed out because waterproofing work is performed on the outer periphery of the arched concrete.
(1) It is necessary to wait for the arched concrete to harden after the required curing period after placing, before waterproofing.
(2) Temporary scaffolding for waterproofing work must be assembled on the outside of the arch-shaped concrete frame, and after the waterproofing work is completed, the temporary scaffolding must be dismantled and removed.
[0004]
The present invention has been made under the circumstances as described above, and the technical problem is that in the construction of the arch culvert, the waterproof construction is performed without waiting for the setting of the arched skeleton-like concrete to be cured. The construction period can be shortened by eliminating the need for scaffold assembly and removal work for waterproofing.
[0005]
[Means for Solving the Problems]
In order to effectively solve the above technical problem, in the construction method of the arch culvert according to the present invention, first, after constructing the base concrete, a frame forming sheet made of a flexible sheet is laid on the base concrete and the peripheral portion thereof. Is fixed to the base concrete, and a waterproof sheet is further laid thereon, and air pressure is applied to the sealed space formed between the base concrete and the casing forming sheet. As a result, the casing forming sheet is supported by the air pressure in a state of bulging together with the waterproof sheet. Next, after arranging reinforcing bars such as reinforcing bars and wire nets in the arch-shaped concrete placement region along the outer periphery of the waterproof sheet, by blowing concrete into the concrete placement region, An arch-shaped frame concrete in which base concrete and a waterproof sheet are integrated is formed, and the outside thereof is filled with a soil material.
[0006]
That is, according to the present invention, as a mold for forming the arch-shaped frame concrete, a frame-forming sheet that is inflated and supported by an air pressure is used, and the frame-forming sheet is expanded in an arch shape. Since the waterproof sheet can be laid before forming, a work scaffold for the waterproof sheet construction is unnecessary. Moreover, since the waterproof sheet is in an integrally joined state with the arch-shaped skeleton concrete formed by spraying concrete on the outer periphery thereof, the placement of the arch-shaped skeleton concrete and its waterproofing work are performed simultaneously. . In addition, after hardening of the arch-shaped frame concrete, if the said air pressure is cancelled | released, the sheet | seat for frame forming can be easily demolded.
[0007]
In the present invention, it is preferable that a large number of anchors protrude in advance on the outer peripheral surface of the waterproof sheet at predetermined intervals. When this anchor is buried in the cast concrete, the waterproof sheet can be firmly fixed to the inner peripheral surface of the arched concrete.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred embodiment of an arch culvert construction method according to the present invention will be described with reference to FIGS. 1 to 4. First, FIG. 1 shows a construction process of an arch culvert according to the present embodiment, that is, the arch culvert 10 is composed of a base concrete 11, an arch-shaped concrete concrete 12 integrally formed thereon, and the arch-shaped concrete. A waterproof sheet 13 joined to the inner peripheral surface of the concrete 12 is provided, and the arch-shaped frame concrete 12 is embedded with an inner reinforcing bar 15 and an outer reinforcing bar 16 such as a wire mesh and a reinforcing bar.
[0009]
In the construction of the arch culvert 10, first, a flat base concrete 11 is placed on a ground G excavated in a groove shape extending in the construction direction (direction orthogonal to the cross section of FIG. 1) by a known method. When the base concrete 11 is cured, as shown in FIG. 2, a casing forming sheet 1 made of a polymer material having a high tensile strength and a high flexibility is laid on the base concrete 11 and further watertight. A waterproof sheet 13 made of a polymer material having properties is laid, and the peripheral edge of the casing forming sheet 1 and the peripheral edges 1a and 13a of the waterproof sheet 13 are fixed to both ends in the width direction of the upper surface of the base concrete 11.
[0010]
The casing forming sheet 1 is formed so as to swell in a kamaboko shape by introducing air pressure. Further, the waterproof sheet 13 has a size obtained by developing the circumferential surface of the casing molding sheet 1, and as shown in FIG. Projected. The hook 14 may be made of metal, and the base portion 14a may be embedded in the waterproof sheet 13 and integrated.
[0011]
As a method of fixing the peripheral edge 1a of the casing forming sheet 1 (and the peripheral edge 13a of the waterproof sheet 13) to the base concrete 11, when the base concrete 11 is placed, the fixing position of the casing forming sheet 1 on the upper surface portion thereof. The anchor bolts 2 are planted at predetermined intervals, and are fastened by nuts 4 that are screwed into the anchor bolts 2 through a rod-like wood 3 in which holes for inserting bolts are previously opened. In this way, the entire periphery of the peripheral edge 1a of the casing-forming sheet 1 (or the peripheral edge 13a of the waterproof sheet 13) is pressed against the upper surface of the base concrete 11 by the wood 3 and fixed in close contact.
[0012]
Note that reference numerals 17 and 18 in FIG. 2 project a part of the reinforcing bars embedded in the base concrete 11 toward the construction area where the rising portions of the arch-shaped frame concrete 12 are formed, and the inner reinforcing bars 15 shown in FIG. And a reinforcing bar joint for connecting to the outer reinforcing bar 16.
[0013]
When the casing forming sheet 1 and the waterproof sheet 13 are laid as described above, a large amount of air is press-fitted into the sealed space S formed between the base concrete 11 and the casing forming sheet 1 shown in FIG. Air pressure P is applied. As a result, as shown in FIG. 4, the casing-forming sheet 1 swells in an arch shape together with the outer waterproof sheet 13. And even after the casing forming sheet 1 and the waterproof sheet 13 are completely inflated, the sealed space S is maintained in a predetermined high pressure state, thereby supporting the arch shape.
[0014]
On the outer periphery of the waterproof sheet 13, inner reinforcing bars 15 such as a wire mesh or a reinforcing bar are disposed. At this time, a large number of hooks 14 projecting from the outer peripheral surface of the waterproof sheet 13 function as a kind of spacer, and therefore, the inner reinforcing bars 15 are disposed at positions appropriately floating from the outer peripheral surface of the waterproof sheet 13. Is done. Further, both ends of the inner reinforcing bar 15 are fixed to the inner reinforcing bar joint portion 17 shown in FIG. 2 by welding or the like.
[0015]
When the inner reinforcing bars 15 are disposed, the concrete is uniformly sprayed onto the outer peripheral surface of the waterproof sheet 13 using a sprayer (not shown) up to a region z indicated by a one-dot chain line in FIG. At this time, the numerous hooks 14 protruding from the waterproof sheet 13 and the inner reinforcing bars 15 provide appropriate flow resistance to the concrete attached to the outer peripheral surface of the waterproof sheet 13. The casing-forming sheet 1 swelled in a kamaboko shape functions as a mold for molding the inner surface of the arch-shaped casing concrete 12 via the waterproof sheet 13, and is thus sprayed on the outer peripheral surface of the waterproof sheet 13. The concrete hardens over time while being held in an arch shape. Further, the outer peripheral surface of the waterproof sheet 13 is joined to the concrete as the concrete hardens, and the hook 14 embedded in the concrete functions as an anchor, so the waterproof sheet 13 is firmly held. Is done.
[0016]
When the placement of the concrete in the region z is completed, the outer reinforcing bars 16 are further arranged on the outer periphery, and both ends thereof are fixed to the outer reinforcing bar joint portion 18 shown in FIG. 2 by welding or the like, and then the concrete is sprayed. The process is resumed, and the casting is performed up to the final casting thickness (for example, about 40 to 50 mm). As a result, as shown in FIGS. 5A and 5B, the inner reinforcing bars 15 and the outer reinforcing bars 16 are embedded, and the waterproof sheet 13 is integrally joined to the entire inner peripheral surface, so that the rising portions 12a on both sides. The arched concrete body 12 is integrally joined to the upper surfaces on both sides in the width direction of the base concrete 11.
[0017]
When the arch-shaped frame concrete 12 is hardened and a required strength is expressed, the supply of compressed air to the sealed space S between the base concrete 11 and the frame forming sheet 1 is stopped, and the sealed space S is opened to the atmosphere. . As a result, the supporting force by the air pressure P is released from the casing forming sheet 1 and is not in contact with the inner surface of the arch-shaped casing concrete 12, so that it can be easily removed from the inner peripheral surface of the waterproof sheet 13. it can. The demolded frame-forming sheet 1 is diverted to the construction of the arch-shaped frame concrete 12 in the next construction section.
[0018]
When the arch culvert 10 as shown in FIG. 1 is constructed by the above-described series of steps, the earth material G ′ is backfilled to the height indicated by the alternate long and short dash line. This backfilling of the earth material G ′ is performed by repeating operations such as rolling out with a layer thickness of about 25 to 30 cm, rolling and compacting.
[0019]
In the above-described embodiment, the reinforcing bars are two layers of the inner side and the outer side. However, this is not limited naturally, and is appropriately determined according to the thickness of the arched concrete body 12. Further, the structure of the hook 14 and other details is not particularly limited to the illustrated one.
[0020]
【The invention's effect】
According to the present invention, the following effects are realized.
(1) The construction period will be shortened because the construction of the arched concrete and the waterproofing work by laying the waterproof sheet are performed at the same time.
(2) There is no need to assemble a temporary scaffold for waterproofing work or to dismantle and remove it.
(3) Since a frame forming sheet that is inflated into an arch shape by air pressure is used as a mold for placing the arch-shaped frame concrete, work such as assembling and dismantling the mold using a large number of members is unnecessary.
(4) Since the waterproof sheet is provided on the inner periphery of the arched concrete, durability is better than when waterproofing is applied to the outer peripheral side.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an arch culvert construction process according to an embodiment of an arch culvert construction method according to the present invention;
FIG. 2 is an explanatory view showing a fixing structure for a casing forming sheet and a waterproof sheet in the embodiment.
FIG. 3 is a partial plan view of a waterproof sheet used in the embodiment.
FIG. 4 is a partial cross-sectional view showing a state in which the casing forming sheet and the waterproof sheet are inflated with air pressure in the embodiment.
5 is an enlarged cross-sectional view showing a portion A and a portion B in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sheet | seat for frame forming 10 Arch culvert 11 Base concrete 12 Arch-shaped frame concrete 13 Waterproof sheet 14 Hook (anchor)
15 Inner reinforcement 16 Outer reinforcement S Sealed space

Claims (2)

Laying a flexible casing-forming sheet on the base concrete and fixing the peripheral edge to the base concrete;
Laying a waterproof sheet on the housing molding sheet;
A step of inflating and supporting the casing molding sheet together with the waterproof sheet by applying air pressure to a sealed space formed between the base concrete and the casing molding sheet; and
Disposing reinforcing bars in the concrete placement region along the outer periphery of the waterproof sheet;
Spraying concrete onto the concrete placement area to form an arch-shaped skeleton concrete integral with the base concrete, reinforcing bars and waterproof sheet;
Backfilling earth material outside the hardened arched concrete, and
An arch culvert construction method characterized by comprising: In the description of claim 1,
The waterproof sheet has an arch culvert construction method characterized in that a large number of anchors are projected in advance on the outer peripheral surface at predetermined intervals.

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