JP2003119753A - Construction method for forming opening of dam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction method for forming an opening for a spillway, a fish pass and the like in a dam body of a dam, which allows, for example, the arched opening to be easily formed, and enables a block inside the opening to be easily removed with rapidity. SOLUTION: The partial opening is formed in the dam body of the dam by going through: a process in which a through-hole in a thickness direction is bored at each of corner parts in an opening forming place in the dam body of the dam by using a core boring device; a process in which the periphery of the opening forming place is cut by inserting a cutting cable into the through- hole of the corner part; a process in which a columnar block, which is cut off from the dam body along a line for cutting conducted by using the cutting cable, is moved to one side of the dam body by a prescribed length, so as to be protruded from the dam body; a process in which a protruded part is sequentially cut off along a longitudinal section, so as to be formed into a small block; and a process in which the cut-off small block is carried out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a construction method for forming an opening for flooding, a fishway, etc. for flood prevention on a dam body.

[0002]

2. Description of the Related Art As a construction method for forming a partial opening in a dam body, a groove-shaped free surface is formed by forming a slot having a predetermined depth around the opening formation portion of the dam body,
Conventionally, a method has been adopted in which the inside partitioned by the free surface is pressure-crushed using a hydraulic pressure crusher or an expansive crushing agent.

According to the above-mentioned conventional method, it is difficult to efficiently form an opening in a levee body made of reinforced concrete,
The cut line has many irregularities, and it is difficult to discharge the separated block. To improve this, use a core drill at each corner of the opening to drill a cable through hole in the thickness direction, and insert a cutting cable through the adjacent through hole to cut the inside of the opening into a columnar shape. A method is proposed in which the columnar material is cut into pieces and the columnar pieces that have been cut off are crushed and removed (JP-A-7-173820).
issue).

[0004]

According to the method of separating the columnar body using the above-mentioned cutting cable, the inside of the opening can be easily separated and a smooth cutting line can be obtained, but the columnar body inside is separated from the bank. There is a problem that it is difficult to crush and take out the body. Moreover, since the four sides of the opening are cut by the cutting cables, only a straight cutting line can be obtained, and for example, an arch-shaped opening cannot be formed. Therefore, it is an object of the present invention to provide an opening forming method capable of easily forming, for example, an arch-shaped opening, and relatively easily and quickly removing a block inside the opening.

[0005]

In order to solve the above problems, the present invention employs the following configurations. That is, the opening forming method according to the present invention includes a step of forming a through hole in the thickness direction using a core boring device at each corner portion of the opening forming portion in the dam body of the dam, and a cutting cable in the through hole of the corner portion. And a step of cutting the periphery of the opening forming portion by inserting the columnar block, which is separated from the bank by a cutting line by the cutting cable, to one side of the bank by a predetermined length to project from the bank And forming a partial opening in the dam body through a step of sequentially separating the protruding portion along the vertical cross section to form a small block, and a step of unloading the separated small block. It has a feature.

In this opening forming method, since the cutting line of the ceiling of the opening is often a curve such as an arch type, it is not cut by using a cutting cable, but a through hole row formed by a core boring machine. Preferably. In addition, because the columnar block that is cut off from the dam body by the peripheral cutting line and the edge is cut off is moved to one side of the dam body, and the portion protruding from the dam body is divided into smaller blocks in order and carried out, It is easy to remove the cutting block from the bank. For this purpose, it is preferable that the outer peripheral surface of the block is tapered by punching the through hole with a slight inclination in advance so that the columnar block can be easily moved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. When forming an opening in the dam body by this opening forming method, first, the scaffolds 2 are attached to both sides of the target embankment body 1 where the opening is to be formed. A core boring device 5 is installed on one of the scaffolds 2, and a through hole 10 communicating with the opposite surface is drilled. In this case, as shown in FIG. 1, scaffolds 2 are assembled on the upper surface of the scaffold 2 and the upper surface of the scaffold 2 on the opposite side to the upper and lower two areas of the planned opening formation, and a large number of through holes are partially formed by the core boring device 5 installed on the upper scaffold 2. The cutting lines formed by the row of through holes are formed by arranging the holes so as to overlap each other and punching the holes. This cutting line becomes the cutting line 6 for the ceiling of the opening. In the illustrated example, the ceiling cutting line 6 is an arch-shaped curve in a front view, and thus the curved cutting line is formed by the through hole array by the core boring device 5 as described above. When the cutting line is linear, the cutting line can be formed by cutting with a cutting cable described later.

While forming the cutting line 6 for the ceiling, through holes 10 formed by the core boring device 5 are formed at least at respective corners of the planned opening formation portion. In addition,
At the time of this perforation, in order to facilitate the extraction of the columnar block separated by the cutting line, the cross-sectional area on the extraction side is large and the cross-sectional area on the opposite side is small,
The piercing direction is slightly inclined to provide a draft taper α (the inclination angle is preferably about 1.5 to 2.5 degrees). Figure 3
4 and FIG. 4 show the arrangement of through holes drilled by the core boring machine, and the area of the portion surrounded by these through holes is
The extraction side shown in FIG. 3 is large, and the opposite side shown in FIG. 4 is small. Reference numeral 8 in the drawing represents an opening to be formed.

When the drilling of the through hole 10 by the core boring device 5 is completed, as shown in FIGS. 5 and 6, a known wire saw device 20 is installed in place of the core boring device 5, and a cutting cable (wire saw) 21 is used. Make a cut. The through holes 10, ... Are for passing the cutting cable 21 for cutting. At the time of cutting, the cutting cable 2 extended from the drive pulley 22 of the wire saw device 20.
1 through one through hole 10 and then another adjacent through hole 1
0, and is pulled back to the drive pulley side of the wire saw device to form a loop, and is circulated while being guided by a plurality of guide pulleys (not shown). By this circulation traveling, the portion surrounded by the loop-shaped cutting cable is cut (wire sawing) by the blade body such as diamond grains provided on the outer peripheral portion of the cutting cable 21. In the illustrated example, the wire saw device 20 is installed on the scaffold 2 on the lower side and the front side.

The drive pulley 22 is constructed so as to be gradually retracted along a predetermined rail 23, and is gradually retracted with the progress of cutting by the loop-shaped cutting cable 21 to prevent the cutting cable from loosening. . Although water is injected into the cutting cable during cutting, this drainage water is sent to the notch tank 32 attached by the submersible pump 30 installed on the scaffold 2. The wire saw device 20 of the illustrated example has a protective cover 2
7 is covered, this is to prevent the risk of cutting the cutting cable, and the operator operates the control switch box 25 at a remote position by remote control. Reference numeral 33 in the figure denotes a separately installed generator.

After the cutting by the wire saw device 20 is completed, the columnar block 50 is separated from the bank by the cutting line 6 on the ceiling and the cutting line 7 by the cutting cables 21, so that the block is removed next. I do. In the present invention, this removal is performed in the following procedure. First, in the case where the surface of the dam body is a relatively gently inclined surface, the core boring device is provided at a predetermined position on the end of the block 50, which is cut off from the dam body, as shown in FIGS. 10 and 11. A plurality of pilot holes 51 in the vertical direction are arranged side by side in the horizontal direction using, and are crushed using a hydraulic crushing device 55 (which may be an expansive crushing agent). In these figures, the prepared holes 51 are all shown by solid lines in order to show the division method of the blocks, but in reality, these prepared holes are drilled one row each time the block is pulled out.

The crushing using the prepared hole 51 proceeds along a surface (a surface perpendicular to the extracting direction) passing through a plurality of prepared holes drilled on a horizontal straight line, and the end of the block is a small block. Is separated as. The hydraulic crushing device 55 is a known method of crushing rock or concrete by inserting a pair of divided wedges 56 into the prepared hole 51, pushing a rod by hydraulic pressure between the divided wedges, and widening the gap between both wedges. belongs to. According to this method, since no explosive is used, it is safe and has less impact. The small blocks 53 thus divided are carried out.

After the portion of the bank 1 facing the inclined surface 1a is divided and removed as a small block, a force in the extracting direction is applied to the columnar block 50 to project it for a predetermined length, and the projecting part is taken in a vertical section. To divide. As a pressurizing method in this case, as shown in FIGS. 7 and 8, one side of the block 50 (the surface on the extraction side) has a U-shaped pressurizing frame 40 in a plan view.
The base parts 40a, 40a of the above are firmly fixed by the anchors 41, ... And the lateral frame 40b of the pressure frame 40 is pressed by the hydraulic jacks 45, 45 in the extracting direction. In this case, the rear portion of the jack 45 is supported by the reaction force receiving stand 47.
Instead of using such a jack, there is also a method of pulling out with a winch.

By the pressure applied by the jack 45, the block 50 is pulled out by a predetermined length and protrudes from the surface of the bank 1, so that this part is cut off and the small block 5 is cut off.
Set to 3. The protrusion length L at this time is, for example, 700 to 12
It is preferable to set it to about 00 mm. Since the end portion of the block is an inclined surface and the volume thereof is reduced accordingly, the protruding length L ′ of this portion can be made larger than the protruding length L of the central portion. If the protruding length L is too long, the weight of the divided small blocks 53 becomes too large, and a large-capacity device is required for unloading, which is not preferable. On the other hand, if the protrusion length L is too short, the number of times the small blocks are cut off and carried out becomes too large, so extra work is required.

The small blocks 53 divided as described above are
The crane 60 installed on the bank 1 lifts and carries out. In this way, the block 50 is gradually removed. It should be noted that when the total withdrawal amount by the jack 45 provided on the extraction side of the block becomes longer to some extent, it is preferable to install the jack 45 on the scaffold 2 on the opposite side and push the block 50 out from the back side, as shown in FIG. . This eliminates the need for fixing the pressurizing frame 40 to the block with an anchor, and thus is more efficient.

In the example shown in FIG. 13, the block 50 is moved to the extraction side to some extent and then pushed by the jack 45. However, a method of pushing the block by the jack 45 from the beginning can be adopted. For example, in the method of pulling out the block 50 with a winch, when the weight of the block is large, a large-scaled winch is required. However, by pushing from the rear with a lightweight and compact jack to promote, simplification of equipment, Workability can be improved.

In this way, the block 50 is divided into lengths L.
While propelling to the extraction side, the division is repeated until finally the entire block is removed from the opening. As a result, the target opening is formed. According to this construction method, since a large impact is not applied to the bank, there is no risk of cracks or the like occurring in the bank. Also, in the case of the illustrated example,
Except for the ceiling part, the block is cut by cutting with a cutting cable, so a smooth cut surface can be obtained. If necessary, the inner surface of the opening after the block is removed may be appropriately finished.

[0018]

As described above, according to the opening forming method of the present invention, the spillway in the dam body is
It became possible to easily and efficiently form openings such as fishways. Since this method does not use a rock drill or gunpowder,
It does not adversely affect other parts and is highly safe. Needless to say, this opening forming method can be used for purposes other than forming openings in dam dam bodies, for example, for forming openings in other concrete structures.

[Brief description of drawings]

FIG. 1 is a side view showing a through hole drilling method in a dam bank.

FIG. 2 is a plan view thereof.

FIG. 3 is a view on arrow A in FIG.

FIG. 4 is a view on arrow B in FIG.

FIG. 5 is a side view showing a cutting method by a wire saw device.

FIG. 6 is a plan view thereof.

FIG. 7 is a side view showing a method of extracting a block using a jack.

FIG. 8 is a plan view thereof.

FIG. 9 is a plan view of a block showing a punching method for division.

FIG. 10 is a sectional view taken along the line CC.

FIG. 11 is an explanatory diagram of a method of unloading a small block by a crane.

FIG. 12 is an explanatory diagram of a method of unloading a small block by a crane.

FIG. 13 is an explanatory diagram of a method of unloading a small block by a crane.

[Explanation of symbols]

1 bank body 2 scaffolding 5 core boring equipment 10 through holes 20 Wire saw device 21 cutting cable 30 submersible pumps 40 pressure frame 45 jack 50 blocks 51 pilot hole 53 small blocks 60 cranes

Claims (6)

[Claims] 1. A step of boring a through hole in a thickness direction by using a core boring device at each corner portion of an opening forming portion of a dam body, and a cutting cable is inserted through the through hole of the corner portion to form the opening. A step of cutting the periphery of the location, a step of moving the columnar block separated from the dam body along the cutting line by the cutting cable to one side of the dam body by a predetermined length to project from the dam body, and the protruding portion The opening of the dam is characterized in that a partial opening is formed in the dam body through a step of sequentially separating the small blocks into a small block along a longitudinal section and a step of carrying out the separated small blocks. Forming method. 2. The cutting line of the ceiling portion of the opening forming portion is
The method for forming an opening of a dam according to claim 1, wherein the dam is formed by arranging a plurality of through holes in a row using a core boring device and punching the holes. 3. A through taper is provided in the through hole so that the vertical section of the block separated from the bank is large on the side extracted from the opening and small on the opposite side.
Or the dam opening forming method described in 2. 4. The dam according to claim 1, wherein when the separated columnar block is moved to one side of the dam body, the block is pushed by a jack from the opposite side of the moving direction. Aperture forming method. 5. A block obtained by arranging a plurality of vertical through-holes at appropriate intervals in a pulled-out block and crushing under pressure with a hydraulic crushing device or an expansive crushing agent using the through-holes. A small block is cut off from the end of the.
5. The dam opening forming method according to any one of 4 to 4. 6. The dam opening forming method according to claim 1, wherein the separated small blocks are carried out by hoisting them with a crane installed on the dam bank.