JPH11117316A - Temporary cofferdam structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the water cutoff properties of temporary cofferdam works. SOLUTION: The temporary cofferdam works have a plurality of precast panels 20 being parted along the vertical direction and peripheral direction of a pier and having the same constitution. The panels 20 have skin plates 20a, vertical beams, horizontal beams 20c and vertical ribs 20d. The plates 20a are bent arcuately, and formed in a cylindrical shape at the time of connection, and partition the outer circumferential surface of cofferdam works. The horizontal beams 20c are fixed onto end faces in the vertical direction of the plates 20a. The horizontal beams 20c are formed in an annular shape at the time of connection in the peripheral and vertical directions. A mortar layer 24 for cutoff is formed between the underside of the horizontal beam 20c of the precast panel 20 at a first stage placed on a footing 14 and the top face of the footing 14. The mortar layer 24 is fastened on the underside side of the horizontal beam 20c, and formed by filling a skirt section 26 downwards extended along the side face of the footing 14 and the inside of a space partitioned by the top face and side face of the footing 14 with mortar.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temporary shutoff structure, and more particularly to a temporary shutoff structure suitable for repairing an underwater structure such as repairing and reinforcing.

[0002]

2. Description of the Related Art Damage such as damage and collapse of structures due to earthquakes is not limited to land-based structures, but also to underwater structures constructed on rivers and seas, such as bridge foundations and seawalls. Has been reached.

[0003] Even when such underwater structures are damaged, it is necessary to take seismic reinforcement measures in the same manner as onshore structures. Conventionally, when performing seismic reinforcement of underwater structures on rivers and seas, it is necessary to remove water from the surroundings of the structure and work in a dry environment. The construction method is generally adopted.

FIG. 10 shows a typical construction state of the double closing method. The double closing method shown in the figure is an example of an application in the case of carrying out reinforcement and repair work of the pier 1, and the temporary closing 3 is constructed so as to surround the outer periphery of the footing 2.

[0005] Temporary cut-off work 3 includes inner and outer walls 3a, 3b formed by driving sheet piles into the underwater ground on the outer peripheral side of the footing 2.
And a plurality of tie rods 3c connecting between the inner and outer walls 3a and 3b.

In this temporary closing work 3, the inner and outer walls 3a, 3b
The renovation work to secure the water stoppage and the stability by filling the middle filling earth and sand 4 in between, to make it dry by removing the water in the inner wall 3a, and to carry out the reinforcement work 5 on the outer periphery of the pier 1 Done.

However, such a conventional double closing method has the following technical problems.

[0008]

That is, in the above-mentioned double closing method, the sheet pile is driven and removed.
Dismantling takes time and effort, and construction and removal costs for temporary structures account for a large proportion of the total construction costs.

Further, as shown in FIG. 10, when a sheet pile is driven under a girder at the top of a bridge, it becomes difficult to construct a long object due to clearance. There is also a problem that the construction takes more time because of the limitations of the machine.

In addition, the double closing method occupies a large area for a long period of time, which hinders running water and hinders water traffic, and has a problem that it is difficult to perform construction year-round.

Further, when the earth filling 4 is filled, there is a possibility that a problem of water pollution may occur when the sand is charged or removed.
Therefore, the present inventors have developed a temporary closing method capable of solving such a problem, and have already proposed it in Japanese Patent Application No. Hei 9-178603.

The construction method according to this application makes it easy to assemble and disassemble by using a precast panel and solves the problem of water pollution. However, according to the subsequent studies, the following problems are found. there were.

In the temporary closing method according to the above-mentioned application, a temporary closing work in which precast panels are assembled in a laminated state is placed on the upper portion of a base portion, and a prestressing force is introduced using a fixing anchor to integrate them. To

However, in such a configuration, if the top end face of the base portion is inclined, or if the top end face has irregularities, or if the embedded metal fitting protrudes from the top end face, the water stopping material and However, there was a problem in that a good water stopping effect could not be obtained due to lack of adhesion.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a temporary shutoff structure capable of obtaining a good water stopping effect.

[0016]

In order to achieve the above object, the present invention provides a method for bending a perimeter of an underwater structure such as a bridge foundation with a temporary deadline, draining the inside of the temporary deadline, In the temporary closing structure for repairing and repairing the underwater structure, the temporary closing work includes, at a construction site, interposing a sealing material at each joint in a circumferential direction and a vertical direction to form the underwater structure. A plurality of precast panels stacked in a cylindrical shape on the outer periphery, the stacked precast panels are mounted on a base portion of the underwater structure, and a plurality of anchors having one end fixed to the base portion. And a prestressing force is introduced into the base portion to be integrated with the base portion, and the lower end face of the first-stage precast panel placed on the base portion and the base portion are Stop between the end face It provided the use mortar layer. According to the temporary closing structure constructed as described above, the precast panel can be manufactured in advance at the factory, so that a high-quality one can be obtained, assembling and dismantling are simplified, and there is no problem of water pollution. The mortar layer for waterproofing is provided between the lower end surface of the first-stage precast panel placed on the base portion and the upper end surface of the base portion. Even if there is a projection of the embedding metal fitting, it is possible to ensure the waterproofness between the two. The precast panel includes a skin plate that defines an outer peripheral surface in a state where the skin plate is connected in a circumferential direction, a plurality of vertical beams vertically fixed to a circumferential edge of the skin plate, and a vertical direction of the skin plate. A plurality of cross beams which are fixed along the inner surface of the precast panel and are formed along the inner surface of the precast panel arranged in the first stage. Providing a skirt portion extending along the outer periphery of the portion, and filling the mortar into a space separated by the cross beam and the outer peripheral surface of the skirt portion and the base portion, thereby reliably forming the mortar layer for waterproofing. Can be. A lower end of the skirt portion penetrates into the underwater ground, and a flexible member is provided on the lower surface side of the cross beam, the leading end side of which is in sliding contact with the upper surface of the base portion to separate the inner side of the space. Can be. According to this configuration, it is possible to prevent the material for forming the mortar layer from flowing out. In the vertical beam,
When the precast panels are connected in the circumferential direction, a hinge structure portion having a concave-convex fitting allowing horizontal movement of the connected precast panels can be provided. According to this configuration, since the shape of the hinge structure is simple, the processing can be easily performed.

[0017]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG.
9 show an embodiment of the temporary closing structure according to the present invention. The temporary deadline structure shown in the figure illustrates an example in which the structure is applied to a repair work such as repair and reinforcement of a bridge 10 which is an underwater structure.

The bridge 10 includes a pier 12 and a footing 14 which is a foundation formed integrally with a lower end thereof. The pier 12 has a substantially circular horizontal section, and the footing 14 has a circular planar shape, and a part of the lower end is buried in the underwater ground 16.

The temporary closing work 18 of the present embodiment is installed so as to bend the outer periphery of the pier 12 and drains water on the inner side thereof to create dry environmental conditions on the outer periphery of the pier 12. used.

The temporary cutoff 18 is a concentric structure having the same shape as the pier 12 and includes a plurality of precast panels 20 having substantially the same configuration and divided along the vertical direction and the circumferential direction of the pier 12. It is a main component. A ring-shaped support 42 is interposed between the temporary deadline 18 and the pier 12 assembled in a cylindrical shape.

In this embodiment, each precast panel 20 has a shape obtained by dividing a circle into four at equal angular intervals, and as shown in FIG.
0a, a plurality of vertical beams 20b, a pair of horizontal beams 20c, and a plurality of vertical ribs 20d.

The skin plate 20a is bent in an arc shape, and when the pre-cas panel 20 is connected in the circumferential and vertical directions, it becomes cylindrical and separates the outer peripheral surface of the temporary closing work 18.

The vertical beams 20b are arranged at both ends in the circumferential direction of the skin plate 20a and at the center thereof, and are fixed in the vertical direction on the inner surface of the skin plate 20a. A pair of longitudinal beams 20 fixed to both ends of the skin plate 20a
A concave portion 20e and a convex portion 20f constituting a hinge structure portion described later are provided on the outer peripheral surface of b in the vertical direction.

The pair of cross beams 20c are formed of circular flat plates, and are fixed to the vertical end faces of the skin plate 20a and the vertical beams 20b. The cross beam 20 c becomes annular when the precast panel 20 is connected in the circumferential vertical direction, and reinforces the strength of the temporary closing work 18. The cross beam 20c is not limited to a pair, but may be a skin plate 20c.
It may be provided in the middle of the vertical direction of a.

Each of the horizontal beams 20c below the precast panel 20 arranged in the first stage has a through hole 20g for an anchor bolt 28 for securing a mortar filling space described later. Note that FIG.
The portion indicated by 0h is an insertion hole for a bolt used when connecting the precast panel 20 in the vertical direction.

The vertical rib 20d is located on the inner peripheral surface side of the skin plate 20a and is extended and fixed in the vertical direction to reinforce the strength of the skin plate 20a. Note that the vertical rib 20d is not always necessary when, for example, the thickness of the skin plate 20a is increased.

The ring-shaped shoring 42 is installed in a stepped manner at a predetermined interval in the vertical direction of the temporary cofferdam 18, and abuts against the outer peripheral surface of the pier 12 as shown in FIGS. The inner ring member 42a and the outer ring member 4 which comes into contact with the inner surface of the longitudinal beam 20b of the precast panel 20 assembled in an annular shape.
2b and a plurality of cutting beams 42c provided between the inner and outer ring members 42a and 42b.

The ring-shaped support 42 constructed as described above
As in the case of the precast panel 20, is divided in the circumferential direction, manufactured in advance as a precast product, transported to a construction site, and assembled into a ring.

In this case, the inner and outer ring members 42a, 42b
The inner and outer diameters of the bridge pier 12 and the temporary
Is designed in accordance with the inner diameter of the vertical beam 20b. If there is a gap between the inner and outer ring members 42a and 42b and the pier 12 or the vertical beam 20b, a wedge or a high-pressure gas is filled in the gap. By inserting an interval adjusting member 44 such as a closed bag, the two are brought into close contact with each other.

Next, the precast panel 20 having the above structure
The procedure for assembling the temporary closing work 18 will be described with reference to FIG. When assembling the temporary closing work 18, the precast panel 20 and the ring-shaped support structure 42 are manufactured in a production yard near the repair site of the bridge 10 and transported to the vicinity of the bridge 10.

On the other hand, as shown in FIGS. 6 and 7, an anchor bolt 28 whose lower end is fixedly penetrated into the footing 14 is planted at a predetermined interval in the circumferential direction.

The transported precast panel 20 and ring-shaped support 42 are first assembled into a ring-shaped support 42 as shown in FIG. 6 and installed on the outer periphery of the pier 12. Supported on sea level.

When the installation of the ring-shaped support 42 is completed,
Using the outer ring member 42b as a guide,
One stage of the precast panel 20 is connected to the outer peripheral side of b in the circumferential direction and assembled.

FIG. 8 shows a connected state of the precast panel 20 at the dividing position. In the connection state shown in the figure, a water-stop sealing material 34, specifically, a water-stop rubber plate is interposed between the vertical beams 20b adjacent in the circumferential direction.
This is performed by inserting a bolt 36 into a through hole drilled in Ob and screwing a nut 38.

The water-stopping sealing material 34 is disposed at both ends of the concave and convex portions 20e and 20f provided on the vertical beam 20b. Each longitudinal beam 20b arranged at the circumferential end of the precast panel 20 has concave and convex portions 20 which can be fitted to each other.
e and f are provided. These concave and convex portions 20e, f
When the longitudinal beams 20b adjacent in the circumferential direction are connected, a hinge structure is formed.

In this case, the through hole into which the bolt 36 is inserted is formed to be longer than the diameter of the bolt 36 in the horizontal direction, and the precast panel 20 connected by the bolt 36 and the nut 38 moves in the horizontal direction. I can do it.

By connecting the bolt 36 and the nut 38, 4
Pieces of precast panels 20 are connected in the circumferential direction,
When the annular portion for the step is formed, after the assembled part is laid down, the precast panels 20 are sequentially laminated on the upper side by the same method, and the dividing positions are similarly connected by the bolts and nuts 36 and 38. .

The member indicated by reference numeral 40 in FIG.
A backing plate provided on one of the linked vertical beams 20b, and the backing plate 40 is used as a guide when the panel 20 is assembled in the circumferential direction.

At the time of assembling the precast panel 20, the precast panel 20 is supported by a float 62 such as a floating body or a pier as shown in FIG. 6, for example. And used as a guide when assembling each precast panel 20 in an annular shape.

At this time, as shown in FIG. 9, between the cross beams 20c of the precast panel 20 positioned in the vertical direction,
With the sealing member 35 interposed, the cross beams 20c are tightened with bolts and nuts.

The assembly of the precast panel 20 as described above is continued, and when the first-stage precast panel 20 reaches the vicinity of the upper surface of the footing 14, it is implanted in the footing 14 as shown in FIG. The anchor bolt 28 is inserted into the insertion hole 20g of the cross beam 20c, and the anchor bolt 28 is fixed to the cross beam 20c by welding or screwing a nut.

At this time, the anchor bolt 28 is fixed at such a position that the lower surface of the cross beam 20c is located at a predetermined distance above the upper surface of the footing 14 to secure the filling interval of the water stopping mortar layer 24. .

The waterproof mortar layer 24 is formed by the first-stage panel 2
A skirt portion 26 fixed to the lower surface of the cross beam 20c and extending downward along the side surface of the footing 14, and is formed by filling mortar into a space defined by the upper and side surfaces of the footing 14. .

The skirt portion 26 is provided only at the first stage of the panel 20 placed on the footing 14. When the precast panel 20 is assembled in an annular shape, the skirt portion 26 is separated from the side surface of the footing 14 by a predetermined distance. As a result, the side surface is annularly surrounded.

In this case, a part of the lower end of the skirt portion 26 is installed so as to penetrate into the underwater ground 16, and if necessary, the backfill soil is laid on the ground 16 to fill the space. To prevent the mortar from flowing out. On the back side of the skirt 26, a reinforcing plate 27 is fixedly provided.

Further, in order to prevent the filled mortar from flowing inward, a flexible member 30 such as a rubber plate is fixed inside the cross beam 20c, and the distal end side of the flexible member 30 is fixed. The distal end of the flexible member 30 is bent along the upper surface of the footing 14 by, for example, being pulled inward with a string or the like.

The mortar for forming the water stopping mortar layer 24 is injected through an injection pipe 32 provided so that one end penetrates the cross beam 20c. Water stop mortar layer 24
Is formed, the assembling work of the precast panel 20 is restarted, and when the lamination connection of the precast panel 20 of the predetermined number of stages is completed, the precast panel 20 and the pier 12 are connected.
A ring-shaped support 42 is installed between the two.

In the case of the present embodiment, as shown in FIG. 4, the ring-shaped supporter 42 is installed at a position where the precast panel 20 is divided in the circumferential direction, that is, at the position of the vertical beam 20c. It is set to correspond.

The ring-shaped supports 42 are installed in multiple stages in the vertical direction corresponding to the size and height of the temporary closing work 18 to be constructed. When the support 42 is installed and the stability of the laminated temporary cutoff 18 is secured, the temporary cutoff 18 having a water-stop structure in which the laminated and connected precast panel 20 and footing 14 are integrated is completed. I do.

When the temporary closing work 18 is completed, the internal water is drained, a dry working space is created around the pier 12, and repair work such as reinforcement of the pier 12 and the footing 14 is performed, and the repair work is completed. Then, water is introduced into the temporary cofferdam 18 and the work reverse to that at the time of assembly is performed, so that the temporary cofferdam 18 is dismantled and removed.

According to the temporary closing structure constructed as described above, the precast panel 20, which is a main part of the temporary closing work 18, is manufactured in advance in a factory, so that a high-quality panel can be obtained. After being transported to the underwater structure rehabilitation site, it is assembled into a ring with sealing materials 34 and 35 interposed between the circumferentially divided portion and the vertically joined portion,
Since the construction is fixed to the footing 14 by the anchor bolts 28, the number of site works such as the driving of a sheet pile is extremely small, and thus the temporary closing work 18 can be constructed easily and quickly.

Further, removal after the renovation work can be easily performed, which is suitable for rapid construction. Further, in the case of the present embodiment, the temporary closing work 18 is constructed on the upper surface side of the footing 14,
Unlike the conventional temporary closing work, which is a single structure unlike a double structure, the temporary closing work 18 is smaller than the size of the footing 14 and does not occupy a large area, so that it does not hinder water traffic. In addition, the temporary closing work 18 of the present invention does not need to be filled with soil, so that the water quality is not polluted.

In the present embodiment, in addition to the above-described functions and effects, the water stopping mortar is provided between the lower end surface of the first-stage precast panel 20 mounted on the footing 14 and the upper end surface of the footing 14. Since the layer 24 is provided, even if the top end surface of the footing 14 has an inclination, unevenness, protrusion of an embedded metal fitting, or the like, the waterproofness between the two can be ensured.

Further, in the case of this embodiment, when the precast panels 20 are connected in the circumferential direction, the concave and convex portions 20e and 20f serving as hinge structures for allowing the connected precast panels 20 to move horizontally are formed. Since it is provided, it is possible to prevent the bending stress from acting on the temporary closing 18 when an unbalanced load is applied to the temporary closing 18.

In this case, the hinge structure of the concave-convex fitting has a simple shape, can be easily processed, and is very advantageous in terms of economy.

In the above-described embodiment, the temporary closing work 18 having a circular cross section is exemplified. However, the present invention is not limited to this shape. For example, the temporary closing work 18 may be formed into a polygonal shape, an elliptical shape, or an oval shape. Can also be applied.

The number of divisions of the precast panel 20 in the circumferential direction is not limited to four, and can be appropriately selected according to the size of the temporary closing work to be constructed.

[0058]

As described above in detail in the embodiments,
According to the temporary closing structure according to the present invention, the following operational effects can be obtained. . The precast panel can be manufactured in a factory, so that a high-quality panel can be obtained, and the precast panel can be diverted, which is advantageous in terms of economy. . Since it has a single structure and a compact structure, it is suitable for rapid construction and does not require a large occupation area, so it is economical and does not hinder water traffic. . The water-stopping mortar layer formed between the lower end face of the cast cast panel and the upper end face of the foundation has fluidity until it hardens, so deformation such as unevenness and inclination of the top end face of the foundation And a good adhesion between the panel and the base portion, and a sufficient water stopping effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a half sectional view of an assembly state of a temporary closing structure according to the present invention.

FIG. 2 is a top view of FIG.

FIG. 3 is a perspective view of a precast panel used in the temporary closing structure shown in FIG.

FIG. 4 is an enlarged view of a main part of FIG. 2;

FIG. 5 is an enlarged view of a portion A in FIG. 1;

FIG. 6 is an explanatory view of an assembled state of the temporary closing structure according to the present invention.

FIG. 7 is an enlarged view of a portion B in FIG. 1;

FIG. 8 is an enlarged view of a portion C in FIG. 2;

FIG. 9 is an enlarged view of a part D in FIG. 1;

FIG. 10 is a plan view and a sectional view showing an example of a conventional double cutoff method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Bridge 12 Bridge pier 14 Footing 18 Temporary closing 20 Precast panel 20a Skin plate 20b Vertical beam 20c Horizontal beam 20d Vertical rib 24 Waterproof mortar layer 26 Skirt part 28 Anchor bolt 32 Injection pipe 34 Waterproof sealing material 35 Sealing material 42 Ring shape Shoring

Claims (4)

[Claims] 1. A temporary deadline structure in which the outer periphery of an underwater structure such as a bridge foundation is bent by a temporary deadline, and the inside of the temporary deadline is drained to repair or reinforce the underwater structure. In the body, the temporary closing work includes a plurality of precast panels that are laminated in a tubular shape on the outer periphery of the underwater structure with a sealing material interposed at each joint in the circumferential and vertical directions at a construction site, The precast panel is installed on a base portion of the underwater structure, and is constructed by integrating the base portion with a plurality of anchors each having one end fixed to the base portion, A temporary closing structure, wherein a mortar layer for waterproofing is provided between a lower end surface of the first-stage precast panel laminated on a base portion and an upper end surface of the base portion. 2. The precast panel, wherein a skin plate defining an outer peripheral surface in a state of being connected in a circumferential direction, a plurality of vertical beams vertically fixed to a peripheral edge of the skin plate, A plurality of cross beams which are fixed along the inner surface of the skin plate in the up-down direction and are formed in an annular shape in a connected state; On the lower surface, a skirt portion extending along the outer periphery of the base portion is provided, and the water blocking mortar layer is filled by filling mortar in a space separated by the cross beam and the outer peripheral surface of the skirt portion and the base portion. The temporary closing structure according to claim 1, wherein the temporary closing structure is formed. 3. A flexible member that penetrates a lower end of the skirt portion into the underwater ground, and has a front end side slidably in contact with a lower surface side of the cross beam and an upper surface of the base portion to separate an inner side of the space. The temporary closing structure according to claim 2, further comprising a sex member. 4. The vertical beam is provided with a hinge structure portion having a concave-convex fitting that allows horizontal movement of the connected precast panel when the precast panel is connected in the circumferential direction. Item 4. The temporary closing structure according to Item 2.