JP2018193836A - Cofferdam construction method - Google Patents

Abstract

To provide a cofferdam construction method which almost dispenses with an underwater work, and achieves improvement of working efficiency, shortening of a construction period, and cost reduction.SOLUTION: A cofferdam construction method for constructing a cofferdam structure 20 by connection of a plurality of cofferdam divided bodies 10 around a bridge pier 1 includes: installing a float pontoon 2 around the bridge pier 1; assembling the cofferdam divided bodies 10 positioned in the lowermost stage on the float pontoon 2; installing suspension means 9 in the upper part of the bridge pier 1, suspending the cofferdam divided body 10 in the lowermost stage, and lowering the cofferdam divided body to a predetermined height; sequentially assembling, connecting and lowering new cofferdam divided bodies 10 onto the cofferdam divided body 10 positioned on the lower side; grounding the cofferdam divided body 10 in the lowermost stage to a foundation part 1b of the bridge pier 1; connecting the plurality of cofferdam divided bodies 10 up to the cofferdam divided body 10 in the uppermost stage and constructing the cofferdam structure 20; and then placing cut-off concrete 17 between an inner peripheral surface of the cofferdam divided body 10 in the lowermost stage and the foundation part 1b, and draining the inside of the cofferdam structure 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a temporary closing method for constructing a temporary closing structure around a pier.

  When repairing a bridge pier installed in water such as a river or the sea, or performing seismic reinforcement work, a temporary closing structure was previously constructed around the pier using steel sheet piles or steel pipe sheet piles. The work space was formed by discharging water and earth and sand between the piers.

  However, the construction method for constructing a temporary closing structure using steel sheet piles or steel pipe sheet piles, etc., requires an extremely long construction period and enormous construction costs. It was done.

  Therefore, various temporary closing methods using steel panels and liner plates have been disclosed (see, for example, Patent Document 1). The construction method of the temporary closing structure described in Patent Document 1 is a construction method for constructing a cylindrical temporary closing structure around the pier, and an annular work platform is provided around the entire required height of the pier. The outer periphery of the platform can be separated from the outer edge toward the center by the required length, and the platform from which the outer periphery has been separated is housed inside the temporary fastening structure and the temporary fastening structure passes therethrough. Build the temporary closing structure on the platform, cut the outer periphery, and pass the temporary closing structure through the platform and lower the fixed structure to the foundation of the pier. It is characterized by.

  According to the temporary closing method described in this Patent Document 1, the divided structures related to the temporary closing structure are sequentially manufactured with a stable posture on the water platform, and the platform is footed or lowered by passing and descending the platform. It can be fixed on a split structure already installed in water. Therefore, the underwater work by submersible workers is reduced, and the equipment for manufacturing the split structure may be transported to the water platform, the unloading is horizontal, and the work time is shortened. It is described.

Japanese Patent No. 4625532

  According to the construction method of the temporary closing structure described in Patent Document 1, it is thought that the construction period can be shortened and the cost can be reduced as compared with the conventional construction method in which the temporary closing structure is constructed with a steel sheet pile or a steel pipe sheet pile. To do. In addition, since the split structure can be manufactured on a platform and less work is performed underwater, work efficiency can be improved and costs can be reduced compared to the conventional temporary closing method using steel panels and liner plates. Think of it as a figure.

  However, in the construction method of the temporary cutoff structure described in Patent Document 1, it is necessary to separate the outer peripheral portion of the platform every time when the divided structure manufactured on the platform is passed and lowered. Accordingly, it is impossible to continuously manufacture, pass, and descend the divided structure, and the work becomes complicated.

  Further, as shown in FIG. 2b and the like of Patent Document 1, the equipment is transported from the equipment carriage or the work carriage to the platform installed on the pier. However, at a site where a difference in water level occurs due to tidal fluctuations in the coastal area, a difference in height occurs between the platform and the equipment carrier, making it impossible to secure one surface of the work yard.

  Furthermore, the divided structure manufactured on the platform must be fixed on the divided structure already installed in the water after passing and descending the platform, and each time underwater work is required.

  Therefore, in view of the above problems, the present inventor has made intensive studies to provide a temporary closing method in which underwater work is almost unnecessary, work efficiency is improved, construction period is shortened, and cost is reduced. The present invention has been reached.

  That is, the present invention relates to a temporary closing method for constructing a temporary closing structure by connecting a plurality of temporary closing divisions around an pier, wherein a float carrier is installed around the pier, On the ship, assemble the temporary cut-off segment located at the lowest stage so as to surround the pier, install a suspension means on the upper part of the pier, and suspend the lower-stage temporary cut-off division body by the suspension means. Lowering and lowering to a predetermined height, and then assembling and connecting a new provisional cut-off divided body on the temporary cut-off divided body located on the lower side, the lower temporary cut-off divided body is moved to the pier. A plurality of the provisional fastening division bodies are connected to the uppermost temporary fastening division body to form a temporary fastening structure, and then the inner peripheral surface of the lowermost temporary fastening division body. Water-stopping concrete is placed between the foundation and the water-stopping concrete. After reduction, and performs inner drainage of the provisional deadline structure.

  In the temporary closing method according to the present invention, the temporary closing divided body includes a liner plate and a reinforcing ring.

  Furthermore, in the temporary closing method according to the present invention, a plurality of guide rollers are disposed inside the temporary closing divided body, and the temporary closing divided body is moved up and down while the guide rollers are in contact with the outer peripheral surface of the pier. It is characterized by that.

  Further, in the temporary closing method according to the present invention, a lifting prevention column for preventing the temporary closing structure from being lifted is provided between the uppermost temporary closing divided body and the upper part of the pier. And

  According to the temporary closing method of the present invention, the assembly of the temporary closing divisions and the connection work of the upper and lower temporary closing divisions can all be performed on the float carrier, so that the work efficiency can be greatly improved, Significant shortening and cost reduction can be achieved.

  In addition, as described above, the assembly of the temporary deadline divisions and the connection work of the upper and lower temporary deadline divisions are performed on the float carrier installed around the pier, so even in the field where the water level difference occurs due to tidal fluctuations in the coastal area, etc. It is possible to secure one side of the work yard.

  In addition, underwater work is only caused when the bottom temporary cut-off divided body settles on the foundation of the pier, and it is not necessary to connect the temporary cut-off divided bodies underwater. Can be reduced, the burden on the operator can be reduced, and the work efficiency can be improved.

  Further, in the temporary closing method according to the present invention, the temporary closing divided body is constituted by the liner plate and the reinforcing ring, whereby the temporary closing divided body can be easily assembled, the working efficiency is improved, and these liner plates are improved. And the reinforcing ring can be reused, and the cost can be reduced.

  Further, in the temporary closing method of the present invention, a plurality of guide rollers are arranged inside the temporary closing divided body, and the temporary divided body is moved up and down in a state where the guide roller is in contact with the outer peripheral surface of the pier, It is possible to raise and lower the temporary cutoff divided body in a state where the positions of the temporary cutoff divided bodies arranged around are kept constant, and it is possible to improve work efficiency.

  Furthermore, in the temporary closing method according to the present invention, an anchor bolt is disposed on the pier by disposing a lifting prevention column for preventing the temporary closing structure from being lifted between the uppermost temporary closing division and the upper part of the pier. There is no need to fix by etc. Further, by using the anchor together, it can be used in a place where the flow velocity is higher.

The schematic plan view which shows the construction state of the temporary closing method which concerns on one Embodiment of this invention. Work explanatory drawing of the dredging work used as the preparatory process of the temporary closing method. The installation state explanatory drawing of the float carrier in the temporary deadline construction method. The installation state explanatory drawing of the suspension stand and electric chain block in the temporary closing method. Explanatory drawing of assembly work of the provisional deadline division body located in the lowest stage in the provisional deadline construction method. The arrangement | positioning explanatory drawing of the following temporary deadline division body, a vertical beam, and a guide roller in the temporary deadline construction method. Explanatory drawing of the bottoming state of the temporary closing structure in the temporary closing method. Explanatory drawing of the standing condition of still water concrete in the temporary closing method. Work explanatory drawing of the drainage work in the temporary deadline structure in the temporary deadline construction method. The installation state explanatory drawing of the scaffold in a temporary deadline structure. Explanatory drawing of the installation state of the cut beam in a temporary deadline structure. Work explanatory drawing of seismic reinforcement work in temporary deadline structure. FIG. 6 is an explanatory diagram of a state in which guide rollers are arranged in the temporary cutoff structure. Explanatory drawing of the removal state of the scaffold in a temporary deadline structure. Explanatory drawing of the removal state of the still water concrete in a temporary closing structure body. Work explanatory drawing of the lifting work of a temporary deadline structure. Explanatory drawing of the completion state of decomposition | disassembly and removal of a temporary deadline structure. Work explanatory drawing of dismantling / removal work of a suspension base and a float carrier. Work explanatory drawing of backfilling work.

  Hereinafter, embodiments of the temporary closing method of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic plan view showing an outline of construction of a temporary closing method according to an embodiment of the present invention, and FIGS. 2 to 19 are views of the temporary closing method (including removal work of a temporary closing structure) of the present embodiment. It is explanatory drawing which shows a working state.

  The present invention is a temporary closing method for constructing a temporary closing structure by connecting a plurality of temporary closing divided bodies around a bridge pier. As shown in FIG. A work yard is constructed by installing the float carrier 2. Spuds 3 are arranged at the four corners of the float carrier 2. Further, a silt fence 4 is installed around the float carrier 2 as a countermeasure against muddy water, and the silt fence 4 is fixed by a wire 5 and a concrete block 6.

  Prior to the installation work of the float carrier 2, as shown in FIG. 2, dredging work around the pier 1 where the float carrier 2 is installed is performed. A self-propelled boat excavator 7 or the like is used for dredging work. After the dredging operation is completed by the self-propelled boat excavator 7 or the like, an assembly-type float carrier 2 is installed so as to surround the pier 1 as shown in FIG.

  Subsequently, as shown in FIG. 4, a suspension base 8 for installing an electric chain block 9 as a suspension means is installed with H-shaped steel so as to surround the bridge support portion 1 a at the upper part of the pier 1. The suspension frame 8 is constructed by bolting H-shaped steels arranged so as to surround the bridge support portion 1a, and does not need to be fixed to the pier 1 or the bridge support portion 1a with an anchor bolt or the like. Therefore, the pier 1 and the bridge support 1a are not damaged.

  When the above preparation work is completed and the necessary materials and equipment are ready on the float carrier 2, the first temporary cut-off division is performed on the float carrier 2 so as to surround the pier 1 as shown in FIG. The assembly work of the body 10 is started. This first temporary cutoff divided body 10 finally becomes the temporary deadline divided body 10 positioned at the lowermost stage of the temporary cutoff divided bodies 10 constituting the temporary cutoff structural body 20.

  Here, the temporary cutoff part 10 is assembled by joining a plurality of liner plates 11 and a plurality of reinforcing rings 12 with bolts. The liner plate 11 is formed of a corrugated thin steel plate, and is lightweight and can be reused. Moreover, the intensity | strength of the temporary closing division body 10 can be increased by joining the reinforcement ring 12 collectively.

  A suspension bracket 13 is attached to the temporary cut-off divided body 10 which is positioned at the lowest stage assembled by joining a plurality of liner plates 11 and a plurality of reinforcing rings 12 with bolts. As shown in FIG. 3, the lowermost temporary cutoff divided body 10 is suspended by the electric chain block 9 of the suspension means.

  Then, after lowering the lowermost temporary cut-off divided body 10 to a predetermined height, a new temporary cut-off divided body 10 is assembled on the lowermost temporary cut-off divided body 10 as shown in FIG.・ Connected. Specifically, the liner plate 11 and the reinforcing ring 12 constituting the new temporary cutoff divided body 10 are sequentially bolted onto the lowermost temporary cutoff divided body 10.

  Furthermore, in the temporary closing method according to the present embodiment, a plurality of vertical beams 14 are disposed inside the temporary closing divided body 10 at a predetermined interval, and a plurality of guide rollers are also spaced at a predetermined interval. 15 is disposed. Although it is possible to secure a certain degree of strength of the temporary cutoff division 10 by applying the reinforcing ring 12 in the assembly of the temporary cutoff division 10, it is possible to further increase the strength by arranging the longitudinal beam 14. Can do.

  In addition, a plurality of guide rollers 15 are arranged inside the temporary cutoff divided body 10 at a predetermined interval, and the rollers 15a related to the guide rollers 15 are brought into contact with the outer peripheral surface of the bridge pier 1 to temporarily In the ascending / descending operation of the dead-end divided body 10, the distance between the outer peripheral surface of the pier 1 and the temporary dead-end divided body 10 is kept constant, that is, the position of the temporary dead-end divided body 10 disposed around the pier 1 is kept constant. The temporary cutoff divided body 10 can be lifted and lowered in the maintained state, and the working efficiency can be improved.

  As described above, after assembling and connecting a new temporary cutoff division 10 on the temporary cutoff division 10 located on the lower side and arranging the vertical beam 14 and the guide roller 15, the electric chain block 9 performs a predetermined operation. Repeat a series of operations to lower the height. Then, at the stage where the lowermost temporary closing divided body 10 bottoms on the upper surface of the footing 1b of the pier 1, the state confirmation of the upper surface of the footing 1b and the bottom confirmation of the temporary closing divided body 10 are performed by underwater work. That is, the temporary closing method according to the present embodiment requires underwater work for the first time at this stage, but does not require underwater work in the process up to that point, and the work efficiency is very high.

  As shown in FIG. 7, a plurality of temporary cut-off divided bodies 10 are formed by attaching the bottom temporary cut-off divided body 10 to the upper surface of the footing 1b and assembling and connecting the uppermost temporary cut-off divided bodies 10. The assembled and connected temporary cutoff structure 20 is constructed. In addition, when the uppermost temporary cut-off divided body 10 is assembled and connected, a cutting beam 16 is provided instead of the guide roller 15.

  Next, as shown in FIG. 8, water-stopping concrete 17 is driven between the inner peripheral surface of the lowermost temporary cutoff divided body 10 and the base portion (upper surface of the footing 1 b of the pier 1) of the temporary cutoff structure 20. Set up.

  Furthermore, in the temporary closing method of the present embodiment, the suspended temporary base 8 is installed so as to surround the uppermost temporary closing divided body 10 and the upper portion of the pier 1, for example, the bridge support portion 1a related to the pier 1 in this embodiment. A plurality of lifting prevention struts 18 for preventing the temporary closing structure 20 from being lifted are disposed with a predetermined interval therebetween. By disposing the plurality of floating prevention posts 18, it is not necessary to fix the foundation portion (footing 1 b) or the like of the pier 1 with an anchor bolt or the like. Fixing can be made more reliable.

  In the drawing, the suspended state of the lowermost temporary closing divided body 10 by the electric chain block 9 is maintained. At this stage, the lowermost temporary closing divided body 10 by the electric chain block 9 which is a hanging means is maintained. The suspended state can be released.

  Then, after the water-stopping concrete 17 is cured, as shown in FIG. 9, the work space is at least between the bridge pier 1 and the temporary closing structure 20 by draining the inside of the temporary closing structure 20 with the drainage pump 19 or the like. Will be formed.

  When actually performing seismic reinforcement work for the pier 1, etc., as shown in FIG. 10, the guide roller 15 is subsequently removed, and a scaffold 21 is provided in the work space between the pier 1 and the temporary closing structure 20. assemble.

  Furthermore, as shown in FIG. 11, a plurality of cutting beams 16 are arranged at predetermined locations below the temporary closing structure 20. In addition, the arrangement | positioning location and the number of arrangement | positioning of the cutting beam 16 are not specifically limited, Considering the water pressure etc. which act on the temporary closing structure 20, etc., it determines suitably.

  At this stage, a work space for performing seismic reinforcement work or the like is completed between the pier 1 and the temporary closing structure 20. Then, using the scaffold 21 assembled in this work space, for example, as shown in FIG.

  As described above, according to the temporary closing method of the present embodiment, the assembly of the temporary closing divided body 10 and the connecting work of the upper and lower temporary closing divided bodies 10 can all be performed on the float carrier 2, so that the work efficiency is improved. It can be remarkably improved, and the construction period can be greatly shortened and the cost can be reduced.

  In addition, since the assembly of the temporary cutoff division 10 and the connection work of the upper and lower temporary cutoff divisions 10 are performed on the float carrier 2 installed around the pier 1, in a site where a water level difference occurs due to tidal fluctuations in the coastal area or the like. In addition, it is possible to secure one side of the work yard. For example, when the water level at the time of high tide rises, the temporary cutoff divided body 10 suspended by the suspending means is raised, and when the water level at low tide is lowered, it is suspended by the suspending means. By lowering the temporary cutoff divided body 10, the height of the float carrier 2 and the temporary deadline divided body 10 in operation can be adjusted, and one surface of the work yard can be secured.

  As described above, the temporary closing method according to the embodiment of the present invention and an example of the earthquake-resistant reinforcement work for the pier using the temporary closing method have been described in detail. Can be removed.

  That is, as shown in FIG. 13, the cutting beam 16 disposed at a predetermined position below the temporary closing structure 20 is removed, and the guide roller 15 is attached.

  Next, the scaffold 21 is removed as shown in FIG. 14, and the waterproof concrete 17 is demolished and removed as shown in FIG.

  When the above preparation for lifting is completed, as shown in FIG. 16, the beam 16 related to the uppermost temporary cut-off divided body 10 is removed, and the lowermost step related to the temporary cut-off structure 20 by the electric chain block 9 of the hanging means. The temporary deadline divided body 10 is raised and disassembled and removed sequentially from the uppermost temporary deadline divided body 10.

  As shown in FIG. 17, when the disassembly / removal of all the temporary cut-off divided bodies 10 constituting the temporary cut-off structure 20 is completed, the suspension base 8 is removed and the float carrier 2 is disassembled as shown in FIG.・ Remove.

  Finally, as shown in FIG. 19, the removal operation of the temporary closing structure 20 is completed by performing the backfilling operation to the planned height by the self-propelled boat excavator 7 or the like.

  As described above, according to the temporary closing method of the present embodiment, the work efficiency can be improved and the cost can be reduced at the stage of constructing the temporary closing structure 20, and the temporary closing structure 20 can be removed. The work efficiency is improved. In addition, the provisional deadline division body 10 constituting the removed temporary deadline structure 20 can be reused, and the construction cost can be reduced.

  As mentioned above, although embodiment of the temporary closing method of this invention was explained in full detail, it should not be understood that the technical idea of this invention is limited substantially. For example, in the temporary closing method of the present invention, it is possible to prevent the temporary closing structure from being lifted by disposing an anti-lifting column. Construction method can be applied. The present invention can be carried out without departing from the gist, with appropriate improvements, changes, or additions based on the inventive ideas and ideas of those skilled in the art.

1: Bridge pier 2: Float carrier 8: Suspension mount 9: Suspension means (electric chain block)
10: Temporary cutoff divided body 11: Liner plate 12: Reinforcing ring 14: Longitudinal beam 15: Guide roller 16: Cut beam 17: Water-stopping concrete 18: Lift prevention column 20: Temporary cutoff structure

Claims (4)

A temporary closing method for constructing a temporary closing structure by connecting a plurality of temporary closing divided bodies around a pier,
Installed a float carrier around the pier,
On the float trolley, assemble the temporary cutoff division located at the lowest stage so as to surround the pier,
Install suspension means on top of the pier,
The lowermost provisional cutoff division is suspended by the suspension means and lowered to a predetermined height,
Sequentially, assembling and connecting a new temporary deadline division on the temporary divisional division located on the lower side, lowering,
After the lowermost provisional cutoff division body settles on the foundation portion of the pier and a plurality of temporary closure division bodies are connected to the uppermost provisional cutoff division body to construct a temporary closure structure, Water-stopping concrete is placed between the inner peripheral surface of the lower temporary cut-off divided body and the foundation,
A temporary closing method characterized by draining the inside of the temporary closing structure after hardening of the water-stopping concrete.   The temporary closing method according to claim 1, wherein the temporary closing divided body includes a liner plate and a reinforcing ring.   A plurality of guide rollers are disposed inside the temporary closing divided body, and the temporary closing divided body is moved up and down in a state where the guide rollers are in contact with the outer peripheral surface of the pier. Item 3. The temporary closing method according to Item 2. A temporary closing method, comprising: a lifting prevention column for preventing the temporary closing structure from being lifted between the uppermost temporary closing divided body and the upper part of the pier.

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