JP2022187300A - Construction method for cofferdam structure and cofferdam structure - Google Patents

Abstract

To provide a construction method for a cofferdam structure capable of securing cut-off performance and reducing the labor and time of the construction.SOLUTION: A construction method for a cofferdam structure comprises steps of: installing multiple hollow piles 10 with upper ends opened in a water bottom 2 around a work area; installing sheet support members 20 fixed with a first waterproof sheet 40 on the water bottom 2 at a side separated from the work area from the hollow piles 10; inserting column bodies 30 into each of the hollow piles 10; installing a second waterproof sheet 50 by spreading between the column bodies 30; and detachably connecting the second waterproof sheet 50 to the first waterproof sheet 40.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for constructing a temporary cofferdam structure and a temporary cofferdam structure.

When repairing or refurbishing an underwater structure built in a river, etc., a temporary cofferdam is provided around the structure. A conventional temporary cofferdam is formed by continuously driving steel sheet piles into the bottom of the water with a vibratory hammer or a press-fitting machine (see Patent Document 1).

JP-A-10-168915

Repair work and renovation work for underwater structures may take several years, and in some cases it can only be done during the dry season of the year. In such a case, a temporary cofferdam is installed at the start of the workable period and removed at the end of the constructable period. In other words, the installation and removal of the temporary cofferdam will be repeated at the same place.
When the temporary cofferdam of Patent Document 1 is used, if the steel sheet piles are driven in the same place, the ground loosens and the water stopping performance of the temporary cofferdam deteriorates. Therefore, it was necessary to change the location where the steel sheet piles are driven. Therefore, it is necessary to adjust the arrangement and allocation of the steel sheet piles and the connection with the existing structure, which complicates the construction work and requires a lot of time and effort.
From such a point of view, it is an object of the present invention to provide a temporary cofferdam structure construction method and a temporary cofferdam structure that can ensure water stopping performance and reduce labor and time for construction.

A first invention for solving such problems is a construction method for a temporary cofferdam structure surrounding an underwater work area. The construction method of such a temporary cofferdam structure includes a pile driving step of driving a plurality of hollow piles having an open upper end on the water bottom around the work area, and a water bottom on the side farther from the work area than the hollow piles. a sheet supporting member installation step of installing a sheet supporting member to which a first waterproof sheet is fixed; a column inserting step of inserting a column into each of the hollow piles; and inserting a second waterproof sheet between the columns. A second waterproof sheet installation step of detachably spanning and a waterproof sheet connecting step of detachably connecting the second waterproof sheet to the first waterproof sheet are provided.
According to the construction method of the temporary cofferdam structure of the present invention, when temporarily removing the temporary cofferdam structure, it is sufficient to simply remove the second waterproof sheet from the first waterproof sheet and the pillars, and extract the pillars from the hollow piles. , hollow piles and sheet support members can be left on the bottom of the water. Therefore, since it is not necessary to repeatedly drive piles or sheet piles into the ground, the ground is not loosened, and the deterioration of the water cutoff performance of the temporary cofferdam can be suppressed. In addition, since there is no need to change the locations where piles and sheet piles are driven, there is no need to adjust the arrangement and layout of piles and sheet piles, or the connection with existing structures. Furthermore, since the steps of temporary removal and re-installation of piles and sheet piles can be omitted, labor and time for construction can be reduced.
In the construction method of the temporary cofferdam structure of the present invention, at the end of the workable period, the second waterproof sheet is removed from the first waterproof sheet and the column, the column is extracted from the hollow pile, In the temporary removal step of leaving the hollow piles and the sheet support member on the bottom of the water, and at the start of the subsequent workable period, the columns are inserted into the hollow piles, and the second column is inserted between the columns. It is preferable to further include a reinstallation step of spanning the waterproof sheet and connecting the second waterproof sheet to the first waterproof sheet. According to such a method, it is possible to reduce the labor and time required for temporary removal and reinstallation of the temporary cofferdam structure.
In addition, each of the above steps may be performed in parallel as far as possible, or the order thereof may be changed. For example, the sheet supporting member installation process may be performed in parallel with the pile driving process, or may be performed before the pile driving process. Further, the column insertion step may be performed in parallel with the seat support member installation step, or may be performed before the seat support member installation step, as long as it is after driving the hollow piles. In addition, the second waterproof sheet installation step may be performed in parallel with the sheet support member installation step, or may be performed before the sheet support member installation step, so long as it is after the columns are installed on the hollow piles. .

A second invention for solving the above problems is a temporary cofferdam structure surrounding an underwater work area. The temporary cofferdam structure includes a plurality of hollow piles driven into the water bottom around the work area and having an open upper end, a sheet support member installed on the water bottom closer to the work area than the hollow piles, and each of the above A pillar inserted into the hollow pile, a first waterproof sheet fixed to the sheet support member, a second waterproof sheet detachably stretched between the pillars, and the second waterproof sheet. and a connecting portion that is detachably connected to the first waterproof sheet.
According to the temporary coffering structure of the present invention, when temporarily removing the temporary coffering structure, the second waterproof sheet is removed from the first waterproof sheet and the column, the column is extracted from the hollow pile, and the hollow pile and the sheet are removed. The support member can be left on the bottom of the water. In addition, when the temporary cofferdam structure is reinstalled, the left hollow piles and sheet support members can be used, so that the ground is not loosened and the deterioration of the water stoppage performance of the temporary cofferdam can be suppressed. Furthermore, there is no need to adjust the arrangement and allocation of piles and sheet piles, and the connection with existing structures, and the process of removing and re-installing piles and sheet piles can be omitted, so that the labor and time of construction can be reduced.
In the temporary cofferdam structure of the present invention, it is preferable that the connection part is waterproof. According to such a configuration, the water stopping performance can be ensured only by closing the connecting portion, and the connecting work is facilitated.
In the temporary cofferdam structure of the present invention, the sheet supporting member includes a sheet pile driven into the water bottom and a shape member fixed to the upper end of the sheet pile, and the first waterproof sheet is attached to the shape member. Fixed ones are preferred. According to such a configuration, it is possible to further improve the water stopping performance.

According to the method for constructing a temporary cofferdam structure and the temporary cofferdam structure of the present invention, it is possible to secure the water stopping performance of the temporary cofferdam structure and reduce the labor and time required for construction.

It is a perspective view showing a temporary cofferdam structure according to an embodiment of the present invention. 1 is a cross-sectional view showing a temporary closing structure according to an embodiment of the present invention; FIG. It is the top view which showed the temporary cofferdam structure which concerns on embodiment of this invention. 1 is an enlarged cross-sectional view showing a temporary cofferdam structure according to an embodiment of the present invention; FIG. It is the perspective view which showed the connection structure of the 2nd waterproof sheet and column of the temporary coffering structure which concerns on embodiment of this invention. (a) is a cross-sectional view showing the pile driving process of the construction method of the temporary cofferdam structure according to the embodiment of the present invention, (b) is a cross-sectional view showing the seat support member installation process, and (c) is a column It is sectional drawing which showed the insertion process. (a) is a cross-sectional view showing a first waterproof sheet fixing step of the method for constructing a temporary cofferdam structure according to an embodiment of the present invention, and (b) is a cross-sectional view showing a second waterproof sheet installing step. (a) is a cross-sectional view showing a state in which the second waterproof sheet is removed in the temporary removal step of the construction method for the temporary cofferdam structure according to the embodiment of the present invention, and (b) shows a state in which the columns are removed. Sectional drawing, (c) is sectional drawing which showed the state which cured the hollow pile. (a) is a cross-sectional view showing the state in which the columns are reinstalled in the reinstallation process of the construction method for the temporary cofferdam structure according to the embodiment of the present invention, and (b) is the state in which the second waterproof sheet is reinstalled. 2 is a cross-sectional view shown; FIG.

A method for constructing a temporary cofferdam structure and a temporary cofferdam structure according to an embodiment of the present invention will be described with reference to the attached drawings. A temporary cofferdam structure is a temporary structure surrounding an underwater work area. The underwater work area is the bottom of the water that is secured by damming the water when repairing or repairing underwater structures such as headworks and weirs built in rivers, or when constructing new underwater structures. work area.

First, the structure of the temporary cofferdam structure will be described. FIG. 1 is a perspective view showing a temporary cofferdam structure according to an embodiment of the present invention, FIG. 2 is a sectional view, and FIG. 3 is a plan view. As shown in FIGS. 1 to 3, the temporary cofferdam structure 1 includes a hollow pile 10, a sheet support member 20, a column 30, a first waterproof sheet 40, a second waterproof sheet 50, and a connecting portion 60. and has.
The hollow piles 10 are piles driven into the water bottom 2 around the work area, and are made of steel pipes. The hollow pile 10 has a bottomed tubular shape with an open upper end. The hollow portion 11 of the hollow pile 10 serves as a space into which the column 30 is inserted. The lower end portion of the hollow pile 10 has a shape (conical shape) in which the central portion protrudes downward, making it easy to drive into the water bottom 2 . The hollow pile 10 is driven vertically so that the upper end is level with the surface of the bottom of the water 2. - 特許庁

The sheet supporting member 20 is a member for supporting the first waterproof sheet 40, and is installed on the bottom of the water on the side (outside) of the hollow pile 10 spaced apart from the work area. As also shown in FIG. 4 , the sheet support member 20 includes sheet piles 21 and shaped members 22 . Here, FIG. 4 is an enlarged sectional view showing the temporary closing structure according to the embodiment of the present invention. The sheet pile 21 is driven into the bottom 2 of the water.
The shape member 22 is a member to which the first waterproof sheet 40 is fixed, and is fixed to the upper end of the sheet pile 21 . The profile 22 is constructed of channel steel and is oriented in a portal cross-section with flanges extending downwardly from both ends of the web. The shape member 22 is placed on the upper end of the sheet pile 21 along the width direction of the sheet pile 21 . An elastic member such as a sponge 25 is laid on the lower surface of the web of the shape member 22 , and the shape member 22 is placed with the sponge 25 pressed against the sheet pile 21 . The elastic member placed on the lower surface of the web is not limited to the sponge 25, and may be another member such as an elastic member made of resin. A bolt 23 for fixing the first waterproof sheet 40 is detachably provided on the outer flange of the shape member 22 (on the side opposite to the work area). A plurality of bolts 23 are provided at a predetermined pitch along the longitudinal direction of the shaped member 22 .

The columns 30 are members that support the second waterproof sheet 50 and stand on the bottom of the water 2 . The column 30 is made of H-shaped steel, and the longitudinal lower portion of the column 30 is inserted into the hollow pile 10 . The upper end of the pillar 30 protrudes above the water surface of the river 3 . The column 30 is arranged so that the flange is parallel to the sheet pile 21 .
The first waterproof sheet 40 is a waterproof and flexible resin sheet, and is fixed to the sheet support member 20 . The first waterproof sheet 40 of this embodiment has a rectangular shape elongated in the longitudinal direction of the shaped member 22 . The first waterproof sheet 40 covers the upper surface of the web of the shape member 22 and adheres to the outer flange, and the edge portion on the flange side is bolted in a watertight state. A connecting portion 60 is fixed to the edge portion of the first waterproof sheet 40 on the column 30 side (work area side).

The second waterproof sheet 50 rises along the pillars 30 and dams up the water of the river 3. - 特許庁The second waterproof sheet 50 is made of the same material as the first waterproof sheet 40 . The second waterproof sheet 50 is stretched between the adjacent columns 30, 30 and has a rectangular shape when viewed from the side. A lower edge of the second waterproof sheet 50 is detachably connected to the first waterproof sheet 40 . The side edges of the second waterproof sheet 50 are detachably connected to the adjacent second waterproof sheet 50 .
The connecting part 60 detachably connects the second waterproof sheet 50 to the first waterproof sheet 40 . The connecting portion 60 is configured by a waterproof line fastener. That is, the connection part 60 connects the elements (coupling teeth) provided at the edge of the first waterproof sheet 40 and the elements (coupling teeth) provided at the lower edge of the second waterproof sheet 50 . It is equipped with a slider for engaging or disengaging, and water blocking is possible in a state where the elements are engaged (a state in which the line fastener is closed). The base material to which the elements are attached is made of resin and is waterproof. The base material of one element is welded to the edge of the first waterproof sheet 40 on the column 30 side, and the base material of the other element is welded to the bottom edge of the second waterproof sheet 50 . It should be noted that the base material is preferably stretchable.
The adjacent second waterproof sheets 50 , 50 are detachably connected to each other by a connecting portion 61 equivalent to the connecting portion 60 .
As shown in FIG. 5 , connecting members 51 for connecting to the pillars 30 are provided on the surfaces of the side edges of the second waterproof sheet 50 facing the pillars 30 . The connecting member 51 has a rope 52 and a hook 53 . The ropes 52 are fixed to the side edges of the second waterproof sheet 50 , and hooks 53 are attached to the ends of the ropes 52 . The hook 53 is a member that is locked in the locking hole 31 formed in the flange of the column 30 . A plurality of connecting members 51 and locking holes 31 are formed at a predetermined pitch in the vertical direction.

Next, a method for constructing the temporary cofferdam structure 1 having the above configuration will be described. The construction method of the temporary cofferdam structure 1 includes a pile driving process, a sheet supporting member installation process, a column insertion process, a first waterproof sheet fixing process, a second waterproof sheet installation process, and a waterproof sheet connection process. , is equipped with These steps are steps for constructing the temporary cofferdam structure 1 .

The pile driving process is a process of driving hollow piles into the water bottom 2 around the work area, as shown in FIG. 6(a). In the pile driving process, steel pipe piles (hollow piles 10) are driven into the sea bed 2 using a vibratory hammer from a barge with a crane. The hollow pile 10 is driven to a depth where the upper end is at the same height as the water bottom 2 with the opening facing upward.
As shown in FIG. 6B, the sheet supporting member installation step is a step of installing the sheet supporting member on the bottom of the water 2 on the side farther from the work area than the hollow piles 10 . In the sheet supporting member installation process of the present embodiment, first, the sheet pile 21 is driven into the bottom of the water 2 using a vibratory hammer. The sheet piles 21 are driven to a depth where the upper end is at the same height as the bottom 2 of the water. The sheet piles 21 are arranged linearly. On the other hand, in the factory, the first waterproof sheet 40 with the line fastener element attached to the edge portion is adhered to the shaped member 22 and further bolted to form a fixing member. Installation of the fixing member is performed after the step of inserting the column.

The column inserting step is a step of inserting the column 30 into the hollow pile 10, as shown in FIG. 6(c). In the column inserting step, the H-shaped steel (column 30) is inserted into the hollow portion 11 of the hollow pile 10 using a lifting device on a barge with a crane.
The first waterproof sheet fixing step is a step of fixing the first waterproof sheet 40 to the upper portion of the sheet supporting member 20, as shown in FIG. 7(b). The step of fixing the first waterproof sheet of the present embodiment is performed in parallel with the rest of the step of installing the sheet supporting member (the step of fixing the fixing member to the sheet pile 21). A fixing member formed by integrating the first waterproof sheet 40 with the shape member 22 is suspended from a barge with a crane, and a diver welds the shape member 22 to the upper end of the sheet pile 21 underwater. Here, since the first waterproof sheet 40 is integrated with the profile 22 in advance, the first waterproof sheet 40 is fixed to the upper part of the sheet supporting member 20 by welding the profile 22 to the sheet pile 21. .

The second waterproof sheet installation step is a step of detachably extending the second waterproof sheet 50 between the pillars. In the second waterproof sheet installation step, as shown in FIG. 7(b), the second waterproof sheet 50 is suspended from a barge with a crane, and a diver underwater connects members provided on the second waterproof sheet 50. The second waterproof sheet 50 is connected to the column 30 by locking the hook 53 of 51 to the locking hole 31 of the column 30 . After that, the adjacent second waterproof sheets 50 , 50 are connected via the connecting portion 61 . Since the connecting portion 61 is a line fastener, the connecting work is easy and can be done in a relatively short time even underwater, thus reducing the burden on the diver.
The waterproof sheet connecting step is a step of detachably connecting the second waterproof sheet 50 to the first waterproof sheet 40 . In the waterproof sheet connecting step, the diver connects the second waterproof sheet 50 to the first waterproof sheet 40 via the connecting portion 60 underwater, following the step of installing the second waterproof sheet 50 . Since the connecting portion 60 is also a wire fastener like the connecting portion 61, the connecting work is easy and can be performed in a relatively short time even underwater, thus reducing the burden on the diver.
By the above steps, the construction step of the temporary cofferdam structure 1 is completed. After that, drainage work is performed on the underground structure side of the temporary cofferdam structure 1 to lower the water level in the work area to a level that does not interfere with the construction work.

The construction method of the temporary cofferdam structure 1 further includes a temporary removal step and a reinstallation step.
In the temporary removal step, at the end of a workable period such as a dry season, the second waterproof sheet 50 is removed from the first waterproof sheet 40 and the pillars 30, the pillars 30 are extracted from the hollow piles 10, and the hollow piles 10 are removed. This is the step of leaving the sheet support member 20 on the bottom of the water 2 . The temporary removal process includes a second waterproof sheet removal process, a pillar removal process, and a lid installation process.
The second waterproof sheet removing step is a step of temporarily removing the second waterproof sheet 50, as shown in FIG. 8(a). In this step, the diver opens the connecting portions 60 and 61 made of wire fasteners underwater and removes the second waterproof sheet 50 from the first waterproof sheet 40 and the pillars 30 . Then, it is pulled up from the barge with a crane. By removing the first waterproof sheet 40, the inside of the work area can be returned to the normal water level.

The column removal step is a step of temporarily removing the column 30, as shown in FIG. 8(b). In this step, the H-shaped steel (column body 30) is pulled out from the hollow pile 10 using a lifting device on a barge with a crane. After that, it is lifted onto a barge and moved to a predetermined storage location. The remaining members, the hollow pile 10 and the sheet support member 20, are left on the bottom 2 of the water.
The lid installing step is a step of installing a lid 70 on the pile head portion of the hollow pile 10, as shown in FIG. 8(c). The lid 70 is for preventing earth and sand from flowing into the hollow pile 10 . In this process, a diver installs the cover 70 on the upper end opening of each hollow stake 10 underwater. The lid 70 includes a cylindrical drooping portion 71 provided on the periphery of a disk-shaped lid body, and a claw portion 72 protruding downward from the lid body. A plurality of claw portions 72 are provided on the lower surface of the lid body and arranged radially. When the lid 70 is installed on the upper end of the hollow pile 10 , the hanging portion 71 and the claw portion 72 sandwich the upper end of the trunk portion of the hollow pile 10 to fix the lid 70 .

In the re-installation process, at the start of the workable period after the non-dry season has passed, the columns 30 are inserted into the hollow piles 10, the second waterproof sheet 50 is stretched between the columns 30, and the second This is the step of connecting the waterproof sheet 50 to the first waterproof sheet 40 . The reinstallation process includes a lid removal process, a pillar installation process, and a second waterproof sheet installation connection process.
The lid removing step is a step of removing the lid 70 from the pile head portion of the hollow pile 10 . In this step, the diver removes the lid 70 underwater. If the lid 70 is not installed, this step is omitted.

The pillar installation step is a step of inserting pillars 30 into the hollow piles 10 left on the bottom of the water 2, as shown in FIG. 9(a). In this step, the column body 30 is inserted into the hollow pile 10 by performing work equivalent to the column body insertion step.
The second waterproof sheet installation and connection step is a step of spanning the second waterproof sheet 50 between the pillars 30 and connecting it to the first waterproof sheet 40, as shown in FIG. 9(a). . In this step, the second waterproof sheet 50 is installed and connected by performing work equivalent to the second waterproof sheet installation step and the connection step.
Reinstallation of the temporary cofferdam structure 1 is completed by the above steps.

When the temporary cofferdam structure 1 is to be completely removed, the steps for constructing the temporary cofferdam structure 1 are reversed. This allows all members to be removed from the water.

According to the temporary coffering structure 1 according to the present embodiment, when temporarily removing the temporary coffering structure 1, the second waterproof sheet 50 is removed from the first waterproof sheet 40 and the columns 30, and the columns 30 are removed from the hollow piles 10. just remove it from the According to the construction method of the temporary cofferdam structure according to the present embodiment, when the temporary cofferdam structure 1 is temporarily removed, the hollow piles 10 and the sheet support members 20 are left on the water bottom. It eliminates the need to repeatedly drive piles and sheet piles. Therefore, the ground is not loosened, and the deterioration of the water cutoff performance of the temporary cofferdam can be suppressed. In addition, since it is not necessary to change the places where the piles and sheet piles are driven in the water bottom 2, it is not necessary to adjust the arrangement and layout of the piles and sheet piles and the connection with existing structures.
In this embodiment, in the temporary removal step, the second waterproof sheet 50 is removed from the first waterproof sheet 40 and the pillars 30, the pillars 30 are extracted from the hollow piles 10, and the hollow piles 10 and the sheet support members 20 are removed from the water bottom 2. Since it is left on the ground, there is no need to remove piles and sheet piles. Therefore, the work in water can be reduced, and the labor and time required for construction can be greatly reduced.
In addition, in the re-installation process, it is only necessary to insert the columns 30 into the hollow piles 10, span the second waterproof sheet 50 between the columns 30, and connect the second waterproof sheet 50 to the first waterproof sheet 40. done. Therefore, the process of re-driving piles and sheet piles can be omitted, so that underwater work can be reduced, and labor and time for construction can be greatly reduced.
Since the element and the base material of the connection part 60 are waterproof, the waterproof performance can be ensured simply by closing the line fastener, which facilitates the connection work. In addition, since the sheet supporting member 20 includes the sheet pile 21 and the shape member 22, and the first waterproof sheet 40 is fixed to the shape member 22, the waterproof performance can be further improved. Since the first waterproof sheet 40 is fixed to the shaped member 22 in advance at a factory or the like, the amount of underwater work is reduced, and the burden on the diver can be reduced.

Although the embodiments for carrying out the present invention have been described above, the present invention is not intended to be limited to the above-described embodiments, and design changes can be made as appropriate without departing from the spirit of the present invention. For example, in the above-described embodiment, the case where the temporary cofferdam structure 1 is constructed in a river was exemplified, but the present invention is not limited to this. The temporary cofferdam structure 1 can be installed even in the shallow waters of the sea.
Moreover, in the above-described embodiment, the column 30 is made of H-shaped steel, but it is not limited to this. For example, the columns may be made of steel pipes or square pipes.

1 Temporary cofferdam structure 2 Water bottom 3 River 10 Hollow pile 20 Sheet support member 21 Sheet pile 22 Profile 30 Column 40 First waterproof sheet 50 Second waterproof sheet 60 Connection part

Claims (5)

A construction method for a temporary cofferdam structure surrounding an underwater work area, comprising:
A pile driving step of driving a plurality of hollow piles having an open upper end in the bottom of the water around the work area;
A sheet supporting member installation step of installing a sheet supporting member to which a first waterproof sheet is fixed on the bottom of the water on the side of the hollow pile spaced apart from the work area;
a column inserting step of inserting a column into each of the hollow piles;
A second waterproof sheet installation step of detachably spanning the second waterproof sheet between the pillars;
and a waterproof sheet connecting step of detachably connecting the second waterproof sheet to the first waterproof sheet. At the end of the workable period, the second waterproof sheet is removed from the first waterproof sheet and the pillars, the pillars are extracted from the hollow piles, and the hollow piles and sheet supporting members are left on the bottom of the water. a temporary removal process to
At the start of the subsequent workable period, the pillars are inserted into the hollow piles, the second waterproof sheet is spanned between the pillars, and the second waterproof sheet is connected to the first waterproof sheet. The construction method of the temporary cofferdam structure according to claim 1, further comprising a re-installation step. A temporary cofferdam structure surrounding an underwater work area, comprising:
a plurality of hollow piles driven into the bottom of the water surrounding the work area and having open upper ends;
a sheet support member installed at the bottom of the water closer to the work area than the hollow pile;
a column body inserted into each of the hollow piles;
a first waterproof sheet fixed to the sheet support member;
a second waterproof sheet detachably stretched between the pillars;
A temporary cofferdam structure, comprising: a connecting portion that detachably connects the second waterproof sheet to the first waterproof sheet. The temporary cofferdam structure according to claim 3, wherein the connection part is waterproof. The sheet supporting member includes a sheet pile driven into the bottom of the water and a shape member fixed to the upper end of the sheet pile,
The temporary cofferdam structure according to claim 3 or 4, wherein the first waterproof sheet is fixed to the shape member.

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