JP3634324B2 - The dam body temporary deadline slit installation method in Sabo Dam and the protector used for the method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a technique for installing a slit in a sabo dam, and more particularly, to a dam body temporary closing method when a slit is provided in an existing dam dam body and a water stop protector used in the method.
[0002]
[Prior art]
Sabo dams are structures that are installed to dampen harmful earth and sand, driftwood, etc. that flow out during heavy rains and floods.
Conventional sabo dams are generally closed dams (impervious dams) that block the debris flow at the dam body and deposit sediment in the upstream pockets to adjust the amount of sand that flows out. Since such a closed sabo dam has a limit in the amount of sand stored, it will not function as a sabo dam when sediment accumulates and becomes full sand. Therefore, even if it was attempted to restore the function of the sabo dam by removing the accumulated earth and sand, it cost as much as constructing a new sabo dam, and dredging was rarely actually performed.
[0003]
In recent sabo projects, an opening (slit) is provided in the center of the dam body, so that innocuous earth and sand are allowed to flow naturally downstream from the slit during normal times. Slit dams (transmission type dams) with a mechanism of stopping tend to be actively constructed.
The reason for this is that when a debris flow occurs, a slit dam (transmission dam) stops megaliths and driftwood. On the other hand, by flowing fine earth and sand downstream, it is possible to suppress downstream erosion. A structure that takes into account the natural environment, such as preventing the disappearance and retreating of the coastline, providing nutrients in the water, and enabling the movement of aquatic organisms such as fish to maintain the river environment close to nature. Because it is.
[0004]
Therefore, the existing closed sabo dam (impervious dam) is cut into a translucent structure by providing slits. When debris flow occurs, megaliths and driftwood are stopped, and during normal times, fine sediment is flowed downstream. Plans to improve the impact on the system have been drafted in debris flow hazard areas and have already been implemented in some areas.
[0005]
[Problems to be solved by the invention]
The slit installation work of the existing sabo dam is usually performed using the wire saw method. In this method, a small hole is drilled in a concrete dam body, a wire saw is passed through, and the wire saw is driven at a high speed using this hole to cut the levee body vertically or horizontally to install a slit. However, in existing sabo dams, a considerable amount of sediment has accumulated in the dam pockets as described above, and a considerable amount of water may have accumulated on the sediment, or there is overflow from the top of the dam body. There may be a constant flow. In such existing sabo dams, when the slit installation work is done, if the reservoir is deep, the diver must work such as diving in the water to make a hole. The water level must be lowered by draining with a large pump so that the excavation work is not hindered. Also, if there was overflow water, the site had to be made dry, such as by turning the waterway separately.
In any case, it takes a lot of work, and it is necessary to install a pump facility or a temporary water channel, which inevitably requires a large amount of work.
[0006]
There are also the following problems. Dam slit installation work is usually done during drought. However, if there is rain on the site during the slit installation work, the work may be interrupted to avoid the dangers associated with increased water. When heavy rain falls and debris flow occurs, the embankment that has been stripped of sedimented sediment for the installation of slits is buried again in the sediment, or the hole is drilled into the hole of the wire saw. Need to start over from the beginning. Even if there is no such thing, it is necessary to consider that it is necessary to provide a provisional deadline facility for ensuring the safety of workers' lives due to water increase or flash flood.
[0007]
Therefore, the purpose of the present invention is to provide a temporary deadline slit installation method for the dam body temporary deadline that can improve the safety and workability of personnel during construction by providing a temporary deadline facility in the construction of providing a slit in an existing dam bank. And it is providing the still water protector used for the construction method.
[0008]
[Means for Solving the Problems]
The method of the present invention employed to achieve the above object is as follows. In other words, it is a construction method that performs slit construction by providing a temporary cutoff water wall on the upstream surface of the dam body of the sabo dam,
Assemble the inner frame with the shape steel material and stretch the wall panel made of steel plate or iron plate outside the inner frame to form a hollow space inside which a human can enter, and the tip piece pointed below the space A lower water blocking wall piece, and an upper water blocking wall piece having the same structure as the lower water blocking wall piece except for the lower tip piece,
One or more upper water blocking wall pieces are stacked and arranged above the lower water blocking wall piece, and the upper water blocking wall piece is bolted to the lower water blocking wall piece so that the upper water blocking wall piece extends from the upper part to the lower part. Forming an internal hollow wedge structure so that it becomes thin in a wedge shape ,
The lower water blocking wall piece is suspended and temporarily placed on the upstream slope of the dam body, and the upper water blocking wall piece is stacked on the lower water blocking wall piece so that the two water blocking wall pieces are mutually on the water surface. after installation by moving from the bolted in position along the upstream side slopes of the dam body, performs a waterproofing treatment to lower the water level inside the wedge structure, both water-stop wall piece from the wedge structure section The dam body temporary deadline characterized by comprising the steps of anchoring to the levee body, then drilling a hole through which the wire saw passes from the upstream side of the dam body, and constructing a slit in the dam body using the hole It is a slit installation method.
[0009]
The protector according to the present invention is a temporary closing water protector constructed on the upstream surface of the dam body of the sabo dam, and the water protector assembles the inner frame with the shape steel material, and a steel plate or an iron plate outside the inner frame. A hollow wall panel made by humans is formed to form a hollow space inside which a human can enter, and a lower water blocking wall piece having a tip piece pointed on the lower side of the space, and a lower stop piece except for the lower tip piece. Using the upper water blocking wall piece having the same structure as the water wall piece,
One or more upper water blocking wall pieces are stacked and arranged above the lower water blocking wall piece, and the upper water blocking wall piece is bolted to the lower water blocking wall piece so that the upper water blocking wall piece extends from the upper part to the lower part. A dam body temporary closing water protector for installing a slit in a dam dam body, which is formed in an internal hollow wedge structure so as to become thin in a wedge shape .
[0010]
The water stop protector is characterized in that its cross section is formed in a substantially U shape or an arch shape.
[0011]
The lower water blocking wall piece has a configuration in which a tip piece whose cross section is a semiconical shape or a half pyramid shape is connected to the lower side of the lower waterstop wall piece.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.
FIG. 1 is a schematic view showing an example of an existing concrete sabo dam (closed dam). FIG. 1 (a) is a perspective view of the sabo dam viewed from the upstream side, and FIG. 1 (b) is a side view. The present invention provides a dam body temporary cut-off for installing a slit (opening) 2 that reaches the river bed from the top of the water passage at the center of the dam body 1 of the sabo dam of the type described above. This paper proposes a slit installation method and a water barrier protector used in the method. In FIG. 1A, the positions where the slits 2 are formed are indicated by hatching.
The width of the slit 2 is appropriately designed according to the situation at the site such as the outflow and accumulation of sediment. Two or more slits may be provided as necessary, but in FIG. 1, only one slit is provided.
What is indicated by reference numeral 3 is a water stop protector according to the present invention, and this protector 3 is manufactured in advance in a wedge shape that is thinned from the upper part to the lower part using a steel material in a factory or the like. It has a hollow structure that has a space where people can enter and perform slit installation work. The protector 3 is divided into two or several pieces in the vertical direction as will be described later, and is formed into a piece that can be carried into a mountain area by a small vehicle or the like.
Each divided piece is hung on the upstream slope of the levee body according to the position of the slit 2 to be installed in the dam body 1 and piled up to be integrated, and then anchored to the dam body and attached. It is done.
[0013]
2 is a side view showing an embodiment of the protector of the present invention, FIG. 3 is an aa arrow view of FIG. 3, and FIG. 4 is an bb arrow view of FIG. As shown in FIGS. 2 to 4, the protector 3 of the present embodiment is configured by vertically stacking several pieces, that is, a lower water blocking wall piece and an upper water blocking wall piece. Hereinafter, a specific configuration of the protector of the present embodiment will be described. The illustrated example is an example in which five pieces (P1 to P5) are stacked on the upstream slope of the bank body 1 in five stages. In the case of this embodiment, the protectors after being stacked are formed with a height of 8 m, a width of 3.2 m, and a depth of 2.5 m.
This protector 3 uses a structural steel material 4 as a vertical frame, horizontal frame, and upper and lower frame, and is provided with a cane 5 as required, and a plurality of temporary fastenings formed by attaching a wall panel 6 to the outside. It is assembled by stacking water wall pieces vertically. That is, in the illustrated example, H steel is used as the inner frame, the same H steel wand is installed, and three rectangular and / or trapezoidal steel plates or iron plates that serve as water blocking walls on the outer side of the frame are provided. 6 is welded and / or bolted, and is assembled so as to be substantially U-shaped in cross section.
[0014]
The construction sequence for installing the slits in the existing dam body using this protector will be described with reference to FIGS. First, the lower water blocking wall piece (tip piece) No. 1 was suspended from the upstream slope of the dam by a crane or the like, and then temporarily fastened with a wire to the dam body, then the upper water barrier piece No. 1 was placed on the lower water barrier piece. 2 are stacked, bolted to each other on the water surface, and then moved to a fixed position along the upstream slope of the bank. Thereafter, the water inside the wedge body is pumped up to lower the water level inside the wedge. In this way, when pumping up the internal water, no. 1 and No. The second piece (protector) is not pushed up by buoyancy, and is gradually pushed strongly against the dam by water pressure, so that the amount of water intruding into the wedge gradually decreases. In this way, caulking is performed on the seam while the water level inside the wedge body is sequentially lowered. Next, the whole piece is anchored to the bank body from the inside, and then a hole 7 through which the wire saw is passed is drilled in the bank body 1 from the downstream side of the bank body. Next, a wire saw is installed on the top of the bank body, and slits are sequentially formed in the bank body 1 using the holes 7.
As described above, if the protector is removed after completion of the predetermined slit construction, the slit installation construction is completed.
FIGS. 5 (a) (b) to 11 (a) (b) show the order in which the protectors are installed on the existing dam body according to the construction method of the present invention.
[0015]
The illustrated protector is constructed such that the water blocking wall 6 is a steel plate and has a substantially U-shaped cross section, but may be an arch type. Further, the lower tip piece can also have a semi-conical shape or a half-pyramidal shape in cross section.
[0016]
【The invention's effect】
According to the present invention, when slit installation work is performed on a bank of an existing sabo dam, even if the amount of stored water is deep, there is no need for a diver to dive into the water and open a hole. In addition, there is no need to install a large-scale pump facility or a temporary waterway. In the unlikely event that heavy rain falls and debris flows occur during the installation of the slits, the temporary cut-off facility causes the exposed dam body to be buried in the earth or sand, or the earth and sand to fall into the wire saw hole opened in the dam body. In addition, there is an effect that it is possible to ensure the safety of workers' lives due to water increase or flash flood.
The protector used in the present invention can be subdivided into two or more pieces in the vertical direction, and can be easily carried into a mountainous area and assembled by a small vehicle or the like. In use, it is not pushed up by buoyancy, and has the effect of being strongly pushed against the dam by water pressure.
[Brief description of the drawings]
FIG. 1 (a) is a perspective view of the sabo dam as viewed from the upstream side, and FIG. 1 (b) is a side view.
FIG. 2 is a side view showing an embodiment of the protector of the present invention.
3 is a view taken along the line aa in FIG. 2;
4 is a view taken along the line bb in FIG. 2;
FIGS. 5 (a) and 5 (b) show a first step of the present construction method.
6 (a) and 6 (b) show a second step of the present construction method.
FIGS. 7A and 7B show the third step of the present construction method.
FIGS. 8A and 8B show a fourth step of the present construction method.
9 (a) and 9 (b) show a fifth step of the present construction method.
FIGS. 10A and 10B show a sixth step of the present construction method.
FIGS. 11 (a) and 11 (b) show a seventh step of the present construction method.
[Explanation of symbols]
1 Embankment 1
2 slit 3 protector 4 frame 5 cane 6 water blocking wall (steel plate or iron plate)
7 Hole for wire saw

Claims (4)

It is a construction method for slit construction by providing a temporary cutoff water wall on the upstream surface of the dam body of the sabo dam,
Assemble the inner frame with the shape steel material and stretch the wall panel made of steel plate or steel plate outside the inner frame to form an internal hollow space for humans to insert, and the tip piece pointed below the space Using a lower water blocking wall piece and an upper water blocking wall piece having the same structure as the lower water blocking wall piece except for the lower tip piece,
One or a plurality of upper water blocking wall pieces are stacked and arranged above the lower water blocking wall piece, and the upper water blocking wall piece is bolted to the lower water blocking wall piece from the upper part toward the lower part. An internal hollow wedge structure is formed so as to become thin in a wedge shape ,
The lower water blocking wall piece is suspended and temporarily placed on the upstream slope of the dam body, and the upper water blocking wall piece is stacked on the lower water blocking wall piece, and the water blocking wall pieces are bolted to each other on the water surface. after installation moved from bonded in position along the upstream side slopes of the dam body, performs a waterproofing treatment to lower the water level inside the wedge structure, Tsutsumi both water-stop wall piece from the wedge structure section A dam body temporary closing slit installation method characterized by anchoring to a body, then drilling a hole through which a wire saw passes from the upstream side of the dam body, and constructing a slit in the dam body using the hole. A temporary water stop protector constructed on the upstream surface of a dam body of a sabo dam, wherein the water stop protector assembles an inner frame with a shape steel material and stretches a wall panel made of a steel plate or an iron plate outside the inner frame. A lower water blocking wall piece having a tip piece that is pointed below the space, and a structure similar to the lower water blocking wall piece except for the lower tip piece. Using the upper water blocking wall piece
One or a plurality of upper water blocking wall pieces are stacked above the lower water blocking wall piece, and the upper water blocking wall piece is bolted to the lower water blocking wall piece from the upper part toward the lower part. A dam body temporary closing water protector for installing a slit in a dam dam body, which is formed in a hollow wedge structure so as to be thin in a wedge shape . The dam body temporary closing water protector for installing a slit in a dam dam body according to claim 2, wherein the water stop protector has a substantially U-shaped or arched cross section. The dam body temporary shut-off water protector according to claim 2 , wherein the lower water blocking wall piece has a structure in which a tip piece having a semi-conical shape or a half-pyramidal shape is connected to a lower side thereof .

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