JPH0941389A - Execution method of temporary cofferdam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the safe economical execution method of a temporary cofferdam by installing and executing the temporary cofferdam in a short period at any time regardless of the water level of a dam, etc. SOLUTION: Pedestal concrete 2 is placed on the foundation ground 5 of a dam upstream section, and each block 1 of a temporary cofferdam having double steel shell structure consisting of partition walls 11, in which opposed surfaces to the wall surface of the dam upstream form recessed sections 4, and having bottom slabs 12 in the blocks 1 in lowermost sections is bottomed on the pedestal concrete 2 while being successively joined. Water in the recessed sections 4 is drained, and the partition walls 11 are removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the case where a water intake provided at the bottom of an existing dam body is added later,
The present invention relates to a temporary deadline construction method effective when a temporary deadline is constructed in contact with an underwater structure, such as when repairing a shaft of a submerged tunnel.

[0002]

2. Description of the Related Art Conventionally, when adding an intake, etc. provided at the bottom of an existing dam levee, the gate is located on the ground on the upstream side of the dam levee by using the low water level period during the winter drought. After installing a temporary deadline structure such as a mold structure, work such as adding an intake is performed. For this reason, the construction period of the temporary deadline is limited, and several low-water periods in winter are required to construct the temporary deadline, so that the construction period becomes longer and the construction cost becomes higher. Further, even in the case of repairing the shaft of the submerged tunnel, there is also a problem in terms of safety and economy since the construction of the temporary deadline requires almost all underwater work by the diver.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and is a safety system capable of contacting an underwater structure in a short period of time to install a temporary shut-off structure. The purpose is to provide an economical and temporary construction method for temporary deadlines.

[0004]

In order to achieve the above-mentioned object, the construction method of the temporary cut-off of the present invention is to place a pedestal concrete on the foundation ground adjacent to an underwater structure and then float it on the water surface. Using the floating pier for work scaffolding and the crane, the surface facing the underwater structure has a partition wall that forms a concave portion, and further arranges a watertight sealing material in the peripheral bearing portion of the concave portion, In addition, the temporary shut-off structure with a double steel shell structure having a bottom slab at the bottom is divided into multiple blocks, and while each block is sequentially joined from the lower part to the upper part, it is submerged by water injection and settles on the pedestal concrete, It is characterized in that after draining the water in the concave portion of the cutoff structure and crimping it to the underwater structure, after placing the pedestal concrete around the lower end of the temporary cutoff structure, the bulkhead is removed. , Also the block of the temporary shut-off structure is sunk To is characterized in that the middle packed ballast material double steel shell structure of each block partition wall.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a procedure for installing a temporary cutoff structure in contact with a dam levee using the temporary cutoff construction method of the present invention will be described below with reference to the drawings. FIG. 3 is a perspective view showing a state where the temporary cut-off structure 1 is seated on the pedestal concrete 2, and the temporary cut-off structure 1 is composed of a plurality of blocks 1A, 1B, 1C, and is shown in FIG. The partition wall 1 whose surface facing the upstream wall surface forms the concave portion 4
1 and the bottom block 1A is composed of a double steel shell structure having a bottom plate 12 on the bottom block 1A.
The blocks 1B and 1C are joined to each other one after another by welding, bolts, clips, wedges, or the like.

In this embodiment, the temporary shutoff structure 1 is
Although it is divided into 3 blocks, 1A, 1B, and 1C,
The number of divisions is not limited to 3, and may be determined according to the size of the temporary cutoff structure 1. Next, the procedure for installing the temporary cutoff structure 1 in contact with the dam dam body 3 will be described. Since the foundation ground 5 is formed in the upstream portion of the dam dam body 3, as shown in FIG. The work gantry 6 is installed in the yard, the shrubs and dust of the foundation of the pedestal concrete 2 are removed by the enclosed grab bucket attached to the truck crane 7, and surveying for the pedestal concrete 2 is performed.

Thereafter, as shown in FIG. 5, the diver 8 cleans the foundation ground 5 which is the foundation of the pedestal concrete 2 and installs the formwork. Complete the pedestal concrete 2 at the ceiling height. Next, as shown in FIG. 6 and FIG. 7 which is a plan view thereof, the placed pedestal concrete 2
The floating pier 20 for work scaffolding is floated on the surface of the water, and is anchored to the wall surface of the dam 3 by using the anchor 21, and the temporary cutoff and settling guide 22 (shown in FIG. 12) is attached by the diver 8 to the anchor bolt. (42 in FIG. 12) is fixed to the dam surface.

Therefore, as shown in FIG. 1, the lowermost block 1A of the block of the temporary shut-off structure 1 having a double steel shell structure is divided into a predetermined position by using the floating pier 20 and the crawler crane 7. Block 1A at the bottom after floating
Water is poured by the water injection pipe 23 and the next block 1B is placed, and the bottom block 1A is sunk to a height at which welding work can be performed, and the next block 1B is placed and joined by welding, bolts, clips, wedges, etc. Finally, until the bottom slab 12 of the bottom block 1A reaches the bottom of the pedestal concrete 2, the blocks are laid and joined as shown in FIG. 8. Water injection is shown in FIG.

In order to maintain the weight balance with the front wall of each block in the double steel shell structure of the partition wall 11 of each block 1A, 1B, 1C when the temporary shut-off structure 1 is sunk, It is desirable to fill the ballast 30 in advance for each block. In addition, as the ballast 30, solid things such as crushed stone, sand, bagged sand, and concrete blocks are preferable in terms of balance.

Each block is hung inside the floating pier 20 by the crawler crane 7 and joined in sequence from the lower part to the upper part. The buoyancy of the double steel shell structure having the bottom slab 12 is utilized to inject water into the inside. By doing so, the deposit can be performed safely. Next, after the temporary shut-off structure 1 has been sunk, the entire temporary shut-off is pulled by the winch toward the dam embankment 3 side in the state of FIG. 9, and as shown in FIG. By draining the water in the concave portion 4 sandwiched between 11 and 11, using the water injection pump 31, the block 1 of the temporary cutoff is dam dam body 3 due to the difference between the external pressure P and the internal pressure shown in FIG.
Fixed to the surface.

When the temporary shut-off structure 1 is sunk, the upstream wall surface of the dam levee body 3 is joined to the peripheral wall bearing portion 14 of the concave portion 4 on the outer side of the partition wall 11 of the temporary shut-off, which is joined to the upstream wall surface of the dam cut-off wall 3, as shown in FIG.
As the watertight sealing material 40 as shown in FIG. 3, for example, a rubber gasket is provided in this embodiment, and the rubber gasket has specifications for maintaining a required expansion / contraction amount against water pressure.

After the temporary cut-off structure 1 is sunk, the remaining pedestal concrete having a U-shaped planar shape shown by 24 in FIG. 1 is placed around the temporary cut-off on the pedestal concrete 2 to form the temporary cut-off structure. The lifting pressure is prevented from acting on the bottom plate 12 of the article 1. In this embodiment shown in FIG. 12, a single-foam sponge 41 for secondary water stop is inserted around the rubber gasket of the peripheral edge support portion 14, and the peripheral edge support portion 14 is anchored to the dam 3 side. It is designed to be fixed with bolts 42.

After the temporary shut-off structure 1 is joined to the dam bank 3, the partition wall 11 is quickly cut into split pieces that can be carried out, and the crawler crane 17 removes the temporary shut-off structure 1, as shown in FIG. A temporary scaffolding structure is fixed to the dam surface with anchor bolts 50 to prevent falling when the water level in the dam body 3 falls. Next, stairs 5 within the temporary deadline
1 and elevator etc. are installed, and the water intake 60 of dam dam body 3
Construction such as installing a water stop gate and installing a screen.

On the other hand, after the construction of the water intake 60 and the like is completed, the scaffold 70 is installed as shown in FIG. 11, the anchor bolts 50 for fixing the temporary shut-off structure 1 are removed, and then the temporary shut-off structure. Water will be poured into 1, and each block will be divided by the diver 8 into a size that can be lifted by the crawler crane 17, and the temporary deadline structure 1 will be removed.
Although the above-described embodiment has been described as applied to a dam levee, the present invention can be applied to a temporary cutoff in contact with an underwater structure such as repair of a shaft of a submerged tunnel or repair of a breakwater.

[0015]

As described above, according to the method for constructing a temporary shutoff of the present invention, a plurality of double steel shell structures having a bottom slab at the bottom can be suspended by a truck crane or the like. Since it is divided into blocks and sequentially poured with water using buoyancy, it is submerged from the bottom to the top each time it is joined, so the work by the diver will be greatly reduced compared to the past, and safety The work cost can be reduced because the construction work is unmanned and prefabricated.

Further, according to the present invention, a concave portion is formed on the surface of the temporary shutoff structure facing the wall surface, and after the temporary shutoff structure is completely sunk, the water in the concave portion is drained, whereby the water pressure difference between the inside and the outside causes the dam. The temporary cutoff can be securely fixed to the surface, and by crushing stones inside the bulkhead of each block when the temporary cutoff structure is sunk, the weight balance of each block can be maintained well and The deadline can be constructed.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a temporary deadline structure applied to a temporary deadline construction method of the present invention.

FIG. 2 is an explanatory diagram showing a state in which each block of the temporary shut-off structure of FIG. 1 is submerged on the pedestal concrete on the upstream surface of the dam body by pouring water into the block.

FIG. 3 is an explanatory view showing a state in which the temporary cut-off structure of FIG. 2 is bottomed on the pedestal concrete.

FIG. 4 is an explanatory diagram of preparation of the foundation ground at the time of installation and construction of the temporary cut-off structure of FIG. 1.

FIG. 5 is an explanatory view showing pouring of pedestal concrete after the preparation of FIG.

FIG. 6 is an explanatory diagram of preparation for temporary shutoff construction after FIG. 5;

FIG. 7 is a plan view of a main part of FIG. 6;

FIG. 8 is an explanatory view of the sunk block of the temporary shutoff structure after FIG. 6;

9 is an explanatory view of joining the temporary shutoff structure to the dam levee side by the difference in internal and external water pressure after the block of FIG. 8 is sunk.

10 is an explanatory view of removing the partition wall of the temporary shut-off structure after FIG.

FIG. 11 is an explanatory diagram of removal of the temporary deadline structure after the temporary deadline construction according to FIG. 10;

FIG. 12 is an enlarged plan sectional view of a main part of a peripheral edge support portion of the temporary cut-off structure of FIG.

[Explanation of symbols]

1 Temporary cut-off structure 2 Pedestal concrete 3 Dam embankment 4 Recessed part 5 Foundation ground 11 Partition wall 12 Bottom plate 14 Perimeter support part 20 Floating pier 30 Ballast material 40 Watertight sealing material

Claims (2)

[Claims] 1. After placing a pedestal concrete on a foundation ground adjacent to an underwater structure, facing a surface of the underwater structure by using a floating scaffold for work scaffolding and a crane which are floated on the water surface. The surface has a partition wall forming a concave portion, the watertight sealing material is further arranged on the peripheral support of the concave portion, and the temporary shut-off structure of the double steel shell structure having the bottom plate at the bottom is divided into a plurality of blocks. Divide it into blocks by sequentially joining each block from the bottom to the top and pour it on the pedestal concrete by pouring water to the bottom, drain the water in the concave part of the temporary cutoff structure and crimp it to the underwater structure, and make a temporary cutoff. A construction method of a temporary deadline in which the partition wall is removed after placing pedestal concrete around the lower end of the structure. 2. The method for constructing a temporary cutoff according to claim 1, wherein when the block of the temporary cutoff structure is sunk, the ballast material is filled in the double steel shell structure of the partition wall of each block.