JP2005264500A - Cofferdam structure and cofferdam closure method for underwater existing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environmentally harmless and economical cofferdam structure and a cofferdam closure method not attended with mass dredging. <P>SOLUTION: In the cofferdam structure for surveying, repairing or reinforcing an underwater existing structure, reinforcing ring bodies of predetermined heights formed by circumferentially connecting a plurality of divided cofferdam steel plates at the outer periphery of the existing structure, and shaped to form a working space with a predetermined space at the outer periphery of the existing structure, are pressed into the water bottom ground around the existing structure while being connected in a plurality of stages in a depth direction, and a cofferdam member extending to the water surface is installed on the reinforcing ring bodies to form a dry working space around the outer periphery of the existing structure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an underwater existing structure, a temporary closing structure for repair and reinforcement, and a temporary closing method.

In order to investigate, repair, and reinforce existing structures such as piers and foundation piles installed in the sea and rivers, temporary work is required to form a work space that is cut off once around the existing structures. As a prior art for that purpose, Japanese Patent Application Laid-Open No. 5-51918 discloses that a box is formed by detachably combining assembly units having a float tank, and an existing structure is inserted in the center of the bottom of the box. An insertion hole is formed, and a shrinkable water-proof packing that is in close contact with the periphery of the existing structure is provided around the insertion hole, and a latch that suspends the box from the existing structure is provided inside the assembly unit. A working box is disclosed in which a gutter is installed and a water drain valve is provided in the float tank.
Japanese Patent Laid-Open No. 2003-232044 discloses that the outer periphery of an underwater structure such as a bridge foundation is surrounded by a cylindrical temporary cutoff wall, the inside of the cylindrical temporary cutoff wall is drained, and the underwater structure is repaired. -In the temporary closing method for removing the cylindrical temporary cutoff wall after completion of repair work such as reinforcement, the temporary cutoff wall is divided into a plurality of panel units divided in the vertical direction along the circumferential direction, After installing the guide frame on the footing part of the underwater structure and locking the inner surface side of each panel unit to the guide frame so that the panel unit is suspended, the lower end side of the panel unit is The panel unit is fixed while water is fixed in the water bottom ground along the outer periphery of the footing portion, and a water stop packing is interposed between the panel units adjacent in the circumferential direction to ensure water tightness. Provisional deadline method is disclosed that coupled in the circumferential direction to form the tubular provisional deadline wall.
JP-A-5-51918 JP 2003-232044 A

  However, in the case of a conventional deadline and a cylindrical cut-off wall with a work box, it is necessary to put out the top of the bottom of the ground, and if the top of the bottom of the ground is deep, it is accompanied by a large amount of dredging, There is a problem that the sea pollution and dredged soil treatment are expensive.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a temporary fastening structure and a temporary fastening method which are environmentally friendly and economical without a large amount of wrinkles, which solves the above-described problems of the prior art.

  In order to solve the above-mentioned problems, the first invention is a temporary cutoff structure for investigating, repairing and reinforcing underwater existing structures. In the circumferential direction, a steel sheet divided into a plurality of parts on the outer periphery of the existing structure is provided in the circumferential direction. A reinforcing ring body having a predetermined height formed by connecting and forming a work space having a predetermined interval on the outer periphery of the existing structure is connected to the existing structure while connecting a plurality of stages in the depth direction. A dry working space is formed on the outer periphery of the existing structure by installing a cut-off member which is press-fitted into the surrounding water bottom ground and extends on the water surface on the reinforcing ring body.

  The second invention is characterized in that, in the temporary closing structure of the first invention, a press-fitting blade is installed at the tip of the lowermost reinforcing ring body.

  According to the third aspect of the present invention, in the temporary closing structure according to the first or second aspect of the present invention, as a press-fitting reaction force means of the reinforcing ring body, a ground anchor, an existing beam, an existing foundation, and a press-fitting reaction force member fixed to an existing structure are provided. It is characterized by being either.

  The fourth aspect of the present invention is the temporary cut-off structure according to any one of the first to third aspects of the present invention, wherein the outermost portion of the existing structure that is positioned in the water is reinforced in the uppermost stage that is press-fitted in the bottom of the ground. A ring-shaped liner plate or a steel ring is installed as a cut-off member connected to the ring body.

  According to a fifth aspect of the present invention, in the temporary cut-off structure according to any one of the first to fourth aspects of the present invention, the reinforcing ring body is connected to a supporting column located inside the reinforcing ring body and is placed in the water bottom ground. It is characterized by press fitting.

  The sixth aspect of the present invention is the temporary closing structure according to any one of the first to fourth aspects of the present invention, wherein the inside of the reinforcing ring body press-fitted into the water bottom ground is made of underwater concrete, water-stopping rubber, rooting, etc. The water is stopped by means.

The seventh invention is characterized in that in the temporary closing method, the construction is performed in the following order of steps.
(1) A step of installing a press-fitting reaction force means on an existing structure in water.
(2) A step of forming a lowermost reinforcing ring body by connecting a plurality of cut-off steel plates on the outer periphery of the existing structure in the circumferential direction.
(3) A step of installing a press-fitting girder and a press-fitting jack on the lowermost reinforcing ring body, and press-fitting the lowermost reinforcing ring body into the foundation via a press-fitting reaction force means, a press-fitting jack, and a guide member.
(4) The process of excavating the water bottom ground cut off by the lowermost reinforcing ring body.
(5) A step of removing the press-fitting girder and the press-in jack, assembling the next reinforcing ring body, and connecting the second-stage reinforcing ring body to the upper part of the lowermost reinforcing ring body.
(6) A step of installing a press-fitting girder and a press-fitting jack on the second-stage reinforcing ring body, and press-fitting the lowermost reinforcing ring body and the second-stage reinforcing ring body into the foundation.
(7) The process is repeated, and the reinforcing ring body is press-fitted from the top of the water bottom ground to a desired depth in the water bottom ground.
(8) A step of installing a ring-shaped liner plate or a steel ring as a cutoff member extending from the upper end of the reinforcing ring body to the water surface.
(9) Excavate from the top of the bottom to the desired depth in the space surrounded by the reinforcing ring body and the ring-shaped liner plate or steel ring, attach the water-stopping material, cast water-stopping concrete, A process that draws water from the deadline structure and forms a dry working space.

In the temporary closing structure for investigating, repairing and reinforcing an existing underwater structure according to the present invention, the outer periphery of the existing structure has a predetermined height formed by connecting a plurality of cut-off steel plates in the circumferential direction. In addition, a reinforcing ring body having a shape that forms a work space of a predetermined interval on the outer periphery of the existing structure is press-fitted into the water bottom ground around the existing structure while being connected in a plurality of stages in the depth direction. By installing a deadline member that extends above the surface of the body and forming a dry work space on the outer periphery of the existing structure, the temporary deadline structure is firmly fixed in the bottom of the ground, requiring large-scale dredging and excavation. In addition, the disposal cost of dredged soil can be reduced and excavation is performed within the temporary cut-off structure, so there is no concern about river and sea pollution, and it is environmentally friendly, economical and safe.
Since the reinforcing ring body is formed of a cut-off steel plate divided into a plurality of parts, transportation and installation are easy.
There are various types of press-fitting into the foundation of the reinforcing ring body by selecting either a ground anchor, an existing beam, an existing foundation, or a press-fit reaction body fixed to an existing structure as a press-fitting reaction force means. It can be adapted to the outer peripheral shape of the existing structure, does not form a useless work space, does not require a large work machine or the like, and when the existing structure is a river pier, the river basin inhibition rate is small.
With the structure in which the reinforcing ring body is press-fitted into the water bottom ground via the support column and guide member located inside the reinforcing ring body, the reinforcing ring body can be accurately press-fitted into the water bottom ground, and the reinforcing ring body When pulling out from the bottom 5 ground, pulling out becomes easy.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment in which the temporary closing structure of the present invention is applied to reinforcement work for a pier that is a bridge foundation, FIG. 2 is a plan view thereof, and FIG. 3 is a longitudinal sectional view taken along line AA. FIG. The pier 1 which is an existing structure has an oval cross-sectional shape, and has a footing portion 2 having a cross-sectional shape such as an oval shape, a circle, and a rectangle larger than the pier 1 at the lower end thereof. It is buried at a predetermined depth from the top end 3.

  The temporary closing structure 4 of the present invention applied when performing such reinforcement work for the pier 1 includes a reinforcing ring body 5 that is press-fitted from the top end 3 of the bottom of the ground to the predetermined depth from the upper end of the footing part 2. The reinforcing ring body 5 is configured by connecting a plurality of cut-off steel plates in the circumferential direction, and has a cross-sectional shape slightly larger than the cross-sectional shape of the footing part 2. Since the reinforcement ring body 5 is press-fitted from the top end 3 of the water bottom ground to a predetermined depth from the upper end of the footing part 2, it is press-fitted in a plurality of stages in the depth direction. The lowermost reinforcing ring body 5 includes a press-fitting blade 6 at the lower end. In this embodiment, a ground anchor 7 installed in the water bottom ground is used as a pressure reaction force means for press-fitting the reinforcing ring body 5 into the water bottom ground. As another press-fitting reaction force means, a ring body fixed to the pier 1 may be used. The press-fitting of the reinforcing ring body 5 into the water bottom ground is performed by installing a press-fitting girder 8 on the reinforcing ring body 5, installing a press-fitting jack 9 on the press-fitting girder 8, and pressing the jack 9 and a ground anchor as a press-fitting reaction force means. 7 is connected. In order to press-fit the reinforcing ring body 5 accurately, a guide member 14 having the pier 1 as a guide is installed inside the reinforcing ring body 5. Even if it adopts a configuration in which a press-fitting girder 8 is installed on a support column 10 which is located inside the reinforcing ring body 5 and connected to the lower end thereof, and the reinforcing ring body 5 is press-fitted into the underwater ground. Good. By press-fitting by the support column 10 and the guide member 14, the reinforcing ring body 5 can be accurately press-fitted into the water bottom ground, and the pulling out of the reinforcing ring body 5 from the water bottom ground becomes easy.

  The reinforcing ring body 5 is press-fitted from the top end 3 of the bottom of the water bottom to a predetermined depth from the upper end of the footing part 2, and a plurality of ring-shaped liner plates 12 are extended so as to extend from the upper end of the reinforcing ring body 5 to the water surface 11. Install. If the water depth is deep, replace the ring liner plate with a steel ring that can withstand water pressure. The ring-shaped liner plate 12 and the steel ring are also configured by connecting members divided into a plurality in the circumferential direction. After the outer periphery of the pier 1 is surrounded by the temporary closing structure 4 constituted by the reinforcing ring body 5 and the ring-shaped liner plate 12, excavation is performed from the top end 3 of the water bottom ground to the upper end of the footing unit 2. Since excavation is performed in the space surrounded by the temporary cut-off structure 1, rivers and the like are not polluted, and dredging and excavation amount can be reduced. Water-stopping concrete 13 or the like is placed between the reinforcing ring body 5 and the upper end of the footing portion 2 to stop the work space surrounded by the temporary fastening structure 4 including the reinforcing ring body 5 and the ring-shaped liner plate 12. , Pumping out the internal water to form a dry working space.

Next, the work procedure of the temporary closing method according to the present invention will be described.
(1) A step of installing a press-fitting reaction force means on an existing structure in water.
(2) A step of forming a lowermost reinforcing ring body by connecting a plurality of cut-off steel plates on the outer periphery of the existing structure in the circumferential direction.
(3) A step of installing a press-fitting girder and a press-fit jack on the lowermost reinforcing ring body, and press-fitting the lowermost reinforcing ring body into the water bottom ground through the press-fitting reaction force means, the press-in jack, and the guide member.
(4) A step of excavating a portion cut off by the lowermost reinforcing ring body.
(5) A step of removing the press-fitting girder and the press-in jack, assembling the next reinforcing ring body, and connecting the second-stage reinforcing ring body to the upper part of the lowermost reinforcing ring body.
(6) A step of installing a press-fitting girder and a press-fitting jack on the second-stage reinforcing ring body, and press-fitting the lowermost reinforcing ring body and the second-stage reinforcing ring body into the water bottom ground.
(7) The process is repeated, and the reinforcing ring body is press-fitted from the top of the water bottom ground to a desired depth in the water bottom ground.
(8) A step of installing a ring-shaped liner plate or a steel ring as a cutoff member extending from the upper end of the reinforcing ring body to the water surface.
(9) Excavate from the top of the bottom to the desired depth in the space surrounded by the reinforcing ring body and the ring-shaped liner plate or steel ring, attach the water-stopping material, cast water-stopping concrete, A process that draws water from the deadline structure and forms a dry working space.

It is a figure which shows one Embodiment of this invention. It is a figure which shows one Embodiment of this invention. It is a figure which shows one Embodiment of this invention.

Explanation of symbols

1: Pier
2: Footing part 3: Top edge of bottom bottom 4: Temporary cut-off structure 5: Reinforcing ring body 6: Press-fit blade 7: Ground anchor 8: Press-in girder 9: Press-in jack 10: Supporting column 11: Water surface 12: By liner play Formed ring body 13: still water concrete 14: guide member

Claims (7)

In a temporary cutoff structure for investigation, repair, and reinforcement of existing structures in water, having a predetermined height formed by connecting a plurality of cutoff steel plates in the circumferential direction on the outer periphery of the existing structure, and A reinforcing ring body having a shape that forms a working space with a predetermined interval between the outer periphery of the existing structure is press-fitted into the water bottom ground around the existing structure while being connected in a plurality of stages in the depth direction. A temporary cut-off structure for an existing structure in water, wherein a cut-off member extending above the water surface is installed on the outer surface of the existing structure to form a dry work space. 2. The provisional cut-off structure for an existing structure in water according to claim 1, wherein a press-fitting blade is installed at the tip of the lowermost reinforcing ring body. The underwater existing structure according to claim 1 or 2, wherein the reinforcing ring body is any one of a ground anchor, an existing foundation, an existing beam, and a reaction body fixed to an existing structure as a press-fitting reaction force means. Temporary cut-off structure for objects. A ring-shaped liner plate or steel ring as a cutoff member connected to the uppermost reinforcing ring body that is press-fitted into the underwater ground is installed on the outer periphery of the portion of the existing structure located in water. The temporary cut-off structure for an existing structure in water according to any one of claims 1 to 3. 5. The provisional cut-off structure for an existing underwater structure according to claim 1, wherein the reinforcing ring body is connected to a supporting column located inside the reinforcing ring body and is press-fitted into a water bottom ground. The existing underwater installation according to any one of claims 1 to 5, wherein the inside of the reinforcing ring body press-fitted into the foundation is water-stopped by means such as underwater concrete, water-stopping rubber, or rooting. Temporary cut-off structure for structures. Temporary cut-off method for existing structures in water, which is constructed in the order of the following steps.
(1) A step of installing a press-fitting reaction force means on an existing structure in water.
(2) A step of forming a lowermost reinforcing ring body by connecting a plurality of cut-off steel plates on the outer periphery of the existing structure in the circumferential direction.
(3) A step of installing a press-fitting girder and a press-fit jack on the lowermost reinforcing ring body, and press-fitting the lowermost reinforcing ring body into the water bottom ground through the press-fitting reaction force means, the press-in jack, and the guide member.
(4) The process of excavating the water bottom ground cut off by the lowermost reinforcing ring body.
(5) A step of removing the press-fitting girder and the press-in jack, assembling the next reinforcing ring body, and connecting the second-stage reinforcing ring body to the upper part of the lowermost reinforcing ring body.
(6) A step of installing a press-fitting girder and a press-fitting jack on the second-stage reinforcing ring body, and press-fitting the lowermost reinforcing ring body and the second-stage reinforcing ring body into the foundation.
(7) The process is repeated, and the reinforcing ring body is press-fitted from the top of the water bottom ground to a desired depth in the water bottom ground.
(8) A step of installing a ring-shaped liner plate or a steel ring as a cutoff member extending from the upper end of the reinforcing ring body to the water surface.
(9) Excavate from the top of the bottom to the desired depth in the space surrounded by the reinforcing ring body and the ring-shaped liner plate or steel ring, attach the water-stopping material, cast water-stopping concrete, A process that draws water from the deadline structure and forms a dry working space.

Images