JP2017106271A - Construction method for sand control weir - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reinforce strength and reduce a construction cost.SOLUTION: A construction method for a sand control weir (100), which has a pair of overflow prevention sections (10a and 10b) which prevents mudflow, flowing down from an upstream side of a river, from overflowing the same and a permeate section (20) which is arranged between the overflow prevention sections and allows water to flow therethrough, comprises the processes to: construct upstream wall sections (1a and 1b); construct downstream wall sections (2a and 2b); connects side wall sections (3a and 3b) to the downstream wall sections at a side of the permeate section; connect curved wall sections (4a and 4b) which are partially curved to the upstream wall sections and the side wall sections; fill a space surrounded by these wall sections with filling materials (5a and 5b); construct the permeate section (20), which traps soil and stones and allows water to flow therethrough, between the pair of overflow prevention sections; and construct slopes (F1 and F4), at the upstream wall sections and the curved wall sections, with downward slopes from upper edges to lower edges toward an upstream side.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for constructing a sabo dam, and more particularly, to a method for constructing a transmission type sabo dam that captures relatively large rocks and driftwood and allows relatively small sediment and flowing water to pass therethrough.

Sabo dams are known as structures for preventing sediment disasters in mountainous areas.
In recent years, an opening is provided in the central part of the sabo dam, and a steel grid-like fence is provided in this opening, so that when a debris flow occurs, huge rocks and driftwood are captured by the fence, A transmission type sabo dam that allows water to pass through has been devised (see, for example, Patent Document 1).
In a transmission type sabo dam as shown in Patent Document 1, a fence body as a transmission part is provided between a pair of non-overflow parts. The non-overflow section is constructed by constructing an outer wall with a steel plate and filling it with soil cement or the like. Here, the upstream end of the non-overflow portion on the transmission portion side has a corner portion formed in a curved surface in order to reduce the impact of the debris flow.

JP 2013-117118 A

However, in the conventional sabo dam, the upstream wall of the non-overflow section is an upright wall, and when the impact of debris flow is received from the front by the wall surface, the weight of sediment and water contained in the debris flow is designed by design. It could not be utilized, and it was necessary to make the cross section of the sabo dam sufficiently large, and it was difficult to reduce the cost.
In order to solve such problems, it is conceivable to make the slope of the wall on the downstream side gentler. However, it is necessary to provide the necessary depth for embedding in the non-overflow area (depth embedded in the bottom of the river). It cannot be secured. Moreover, since deepening the root depth increases the height of the non-overflow section, the sabo dam becomes huge as a result, making it difficult to reduce costs.

  Then, this invention is made | formed in view of the said problem, and it aims at providing the construction method of the sabo dam which can aim at the improvement of an intensity | strength and reduction of cost.

  In order to solve the above-mentioned problems, the present invention includes a pair of non-overflow portions that prevent overflow of a debris flow flowing from the upstream side, and a permeation portion that is provided between the non-overflow portions and transmits running water. A method of constructing a sabo dam, the step of constructing an upstream wall portion, the step of constructing a downstream wall portion, the step of constructing a side wall portion continuous with the downstream wall portion on the transmission portion side, and the upstream wall A step of constructing a curved wall portion that is continuous with the wall portion and the side wall portion, and at least part of which is formed in a curved shape, a step of filling a filling material in a space surrounded by these wall portions, A step of constructing a permeation part that captures debris between a pair of non-overflowing parts and transmits running water; and downward toward the upstream side from the upper end to the lower end of the upstream wall part and the curved wall part. And a step of forming an inclined slope.

  Moreover, it is preferable to construct | assemble the said curved wall part with a some steel plate panel.

Further, the steel plate panel is formed such that the upper edge and the lower edge are parallel, and the cross section in the direction perpendicular to the normal surface of the curved portion is an arc having a central angle of 90 °, the curved wall portion is It is preferable that the upper and lower edges of the steel plate panel are stacked and constructed so as to be perpendicular to the slope.

  Moreover, it is preferable to cut off the upper end of the steel plate panel arrange | positioned at the upper end of the said curved wall part along the top end of the said non-overflow part.

  Moreover, it is preferable that the steel plate panel arrange | positioned at the upper end of the said curved wall part makes the length of the circular arc of a curved part shorter than other steel plate panels, and makes height low.

  Moreover, it is preferable to cut off the lower end of the steel plate panel arrange | positioned at the lower end of the said curved wall part along the bottom face of the said non-overflow part.

  Moreover, it is preferable to dig a ground according to the protrusion to the bottom face of the said non-overflow part of the steel plate panel arrange | positioned at the lower end of the said curved wall part.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to ease the impact of a debris flow, cost reduction can be aimed at.

It is a perspective view of a sabo dam. It is the perspective view which looked at the wall part of the sabo dam from the upstream. It is the perspective view which looked at the wall part of the sabo dam from the downstream side. It is the perspective view which looked at the side wall part of the sabo dam from the front side. It is a flowchart which shows the construction method of a sabo dam. It is a figure explaining the force which acts on a sabo dam when debris flow occurs.

  Preferred embodiments of the present invention will be described with reference to the drawings. In addition, embodiment shown below is one illustration and can take various embodiment in the scope of the present invention.

[Sabo dam structure]
As shown in FIGS. 1 to 4, the sabo dam 100 includes a non-overflow portion 10a installed on the foundation concrete 11a, a non-overflow portion 10b installed on the foundation concrete 11b, and a non-overflow portion 10a. And a non-overflow portion 10b.

<Non-overflow section>
The pair of non-overflow portions 10a and 10b prevent debris flow flowing from the upstream side of the river, and include upstream wall portions 1a and 1b, downstream wall portions 2a and 2b, and side wall portions 3a and 3b. The curved wall portions 4a and 4b, the filling materials 5a and 5b, and the top end protection materials 6a and 6b are provided.

(Upstream wall)
The upstream wall portions 1a and 1b face the upstream of the river and are wall portions that receive the impact of flowing water and debris flow from the upstream. The upstream wall portions 1a and 1b are constructed by connecting a plurality of rectangular plate-shaped steel plate panels whose cross sections are formed in a wave shape. The steel plate panel has a steel plate, reinforcing ribs installed along the periphery of the steel plate, a flange for providing mutual connection, etc., and a bolt through hole for providing mutual connection is formed in the flange. . Further, the steel plate has a corrugated cross section, and the direction of the wave (the maximum inclination line connecting the peak and the valley bottom) may be horizontal or vertical. The steel plate panels are connected to each other by bolts and nuts, and a seal tape or the like may be attached to the joints to stop the water. Although the steel plate panels constituting the upstream wall portions 1a and 1b are each formed in a wave shape, they are formed in a substantially flat shape when viewed as the entire wall portion. The upstream wall portions 1a and 1b are constructed such that a slope F1 that slopes downward toward the upstream side is formed from the upper end toward the lower end.

(Downstream wall)
The downstream walls 2a and 2b face the downstream of the river, and are arranged at a predetermined interval from the upstream walls 1a and 1b. The downstream wall portions 2a and 2b are constructed by connecting a plurality of rectangular plate-shaped steel plate panels whose cross sections are formed in a wave shape. The steel plate panel has a steel plate, reinforcing ribs installed along the periphery of the steel plate, a flange for providing mutual connection, etc., and a bolt through hole for providing mutual connection is formed in the flange. . Further, the steel plate has a corrugated cross section, and the direction of the wave (the maximum inclination line connecting the peak and the valley bottom) may be horizontal or vertical. The steel plate panels are connected to each other by bolts and nuts, and a seal tape or the like may be attached to the joints to stop the water. Although the steel plate panels constituting the downstream wall portions 2a and 2b are each formed in a wave shape, they are formed in a substantially flat shape when viewed as the entire wall portion. The downstream walls 2a and 2b are constructed so as to incline downward toward the downstream side from the upper end toward the lower end. The downstream wall portions 2a and 2b may use concrete panels instead of steel plate panels.

(Sidewall)
The side wall portions 3a and 3b face the transmission portion 20, and are provided so as to be continuous with the end portions of the downstream wall portions 2a and 2b on the transmission portion 20 side. The side wall portions 3a and 3b are constructed by connecting a plurality of rectangular plate-shaped steel plate panels whose cross sections are formed in a wave shape. The steel plate panel has a steel plate, reinforcing ribs installed along the periphery of the steel plate, a flange for providing mutual connection, etc., and a bolt through hole for providing mutual connection is formed in the flange. . Further, the steel plate has a corrugated cross section, and the direction of the wave (the maximum inclination line connecting the peak and the valley bottom) may be horizontal or vertical. The steel plate panels are connected to each other by bolts and nuts, and a seal tape or the like may be attached to the joints to stop the water. Although the steel plate panels constituting the side walls 3a and 3b are each formed in a wave shape, they are formed in a substantially flat shape when viewed as the entire wall. The side wall portions 3a and 3b are constructed so as to stand upright on the upper surfaces of the foundation concrete 11a and 11b.

(Curved wall)
The curved wall portions 4a and 4b are wall portions that are continuous with the end portion on the transmitting portion 20 side of the upstream wall portions 1a and 1b and the upstream end portion of the side wall portions 3a and 3b, and at least a part thereof is curved. Is formed.
The curved wall portions 4a and 4b are steel plate panels in which at least a part (upstream corner portion of the non-overflow portions 10a and 10b) is formed in an arc shape having a central angle of 90 ° in a cross section perpendicular to the slope F4. It is constructed by connecting multiple sheets. The curved surfaces of the curved walls 4a and 4b form a circumferential surface with a central angle of 90 °. The steel plate panel that forms the curved walls 4a and 4b has a pair of steel plates, a reinforcing rib installed along the periphery of the steel plate, and a flange for mutual connection, and arranged in a vertical direction. The flanges are straight plate materials, and the pair of flanges arranged in the horizontal direction are arc-shaped plate materials in plan view. In addition, bolt through holes for mutual connection are formed in the flange, the steel plate is corrugated in cross section, and the wave direction (maximum slope line connecting the peak and valley bottom) is horizontal or vertical. Also good.
The curved walls 4a and 4b are not easily damaged when huge rocks, driftwood, or the like collide with each other, and when the debris flow that flows down flows into the transmission part 20, a spiral flow is difficult to occur.

The curved walls 4a and 4b are constructed such that a slope F4 is formed that is inclined downward toward the upstream side from the upper end toward the lower end.
The curved wall portions 4a and 4b are constructed such that the upper edge and the lower edge of the steel plate panel whose cross section is formed in an arc shape are stacked so as to be perpendicular to the slope F4 of the curved wall portions 4a and 4b. . That is, the areas where the curved walls 4a and 4b are constructed are divided and stacked along a direction perpendicular to the slope F4. This is because if the regions where the curved wall portions 4a and 4b are to be constructed are divided in the horizontal direction, the curved wall portions 4a and 4b need to be formed in an elliptical cross section. This is because it is necessary to gradually change the curvatures of the upper end and the lower end of the steel plate, which makes it very difficult to manufacture the steel plate panel, which takes time and cost.
Here, the upper end of the steel plate panel arrange | positioned at the upper end of curved wall part 4a, 4b is cut off along the top edge of the non-overflow part 10a, 10b. The lower end of the steel plate panel arrange | positioned at the lower end of curved wall part 4a, 4b is cut off along the bottom face of non-overflow part 10a, 10b.

(Filling material)
The filling materials 5a and 5b are soil cements produced by stirring and kneading the locally generated earth and sand generated when the foundation concrete 11a and 11b and the foundation concrete 21 (described later) are installed, and cement / cement milk. The upstream wall portions 1a and 1b, the downstream wall portions 2a and 2b, the side wall portions 3a and 3b, and the curved wall portions 4a and 4b are placed in a space. Due to the solidification of the filling materials 5a and 5b, the impact of the debris flow is received by the weight of the filling materials 5a and 5b.
Further, since the filling materials 5a and 5b are filled along the inner surface of each wall portion, when solidified, the upstream surface formed along the inner surfaces of the upstream wall portion and the curved wall portion has an upper end. A slope that slopes downward toward the upstream side toward the lower end is formed.

(Top edge protection material)
The top end protection members 6a and 6b cover the upper surfaces of the filling materials 5a and 5b placed in the space surrounded by the walls, and are made of concrete. The top end protection members 6a and 6b function as a protective layer (water blocking layer) for the filling materials 5a and 5b.

<Transmission part>
As shown in FIG. 1, the permeation | transmission part 20 is provided between the non-overflow part 10a and the non-overflow part 10b, and permeate | transmits flowing water.
The permeation | transmission part 20 is provided with the foundation concrete 21 provided in the bottom part of the river, and the fence body 22 which assembled the steel or concrete pillars installed in the foundation concrete 21. As shown in FIG. The permeation | transmission part 20 makes the fence 22 pass the river water and small earth and sand, and captures a huge rock and driftwood at the time of debris flow generation | occurrence | production.

[Sabo dam construction method]
The construction method of the sabo dam 100 is as shown in FIG.
First, foundation concrete 11a, 11b for the non-overflow portions 10a, 10b is placed at a position where the sabo dam 100 is provided (step S1).
Next, the upstream wall portions 1a and 1b, the downstream wall portions 2a and 2b, the side wall portions 3a and 3b, and the curved wall portions 4a and 4b are constructed on the foundation concrete 11a and 11b (step S2). Here, the construction order of each wall portion is arbitrary, and any wall portion may be constructed first or simultaneously.

Here, the upstream wall portions 1a and 1b are connected in a state where a plurality of steel plate panels are inclined with respect to the upper surfaces of the foundation concrete 11a and 11b so as to be inclined downward toward the upstream side from the upper end toward the lower end. And build. That is, the upstream wall portions 1a and 1b have the slope F1 when the construction of the non-overflow portions 10a and 10b is completed.
The downstream wall portions 2a and 2b are constructed by connecting a plurality of steel plate panels in an inclined state with respect to the upper surface of the foundation concrete 11a and 11b so as to incline downward toward the downstream side from the upper end to the lower end. To do. That is, the downstream wall portions 2a and 2b have the slope F2 when the construction of the non-overflow portions 10a and 10b is completed.
The side wall portions 3a and 3b are constructed by connecting a plurality of steel plate panels so as to stand upright with respect to the upper surfaces of the foundation concrete 11a and 11b.
The curved wall portions 4a and 4b are constructed by connecting a plurality of steel plate panels so as to incline downward toward the upstream side from the upper end toward the lower end. That is, the curved wall portions 4a and 4b have the slope F4 when the construction of the non-overflow portions 10a and 10b is completed.
The curved walls 4a and 4b are formed by stacking a plurality of steel plate panels having an arc-shaped cross section with a central angle of 90 ° along the slope of the slope F4. That is, the steel plate panels are stacked in a state where the steel plate panels are inclined so that parallel upper and lower edges of the steel plate panels are perpendicular to the formed slope F4.

Here, as for the steel plate panel arrange | positioned at the upper end of curved wall part 4a, 4b, the upper end part is cut off along the top edge of non-overflow part 10a, 10b in advance. Moreover, the steel plate panel arrange | positioned at the lower end of curved wall part 4a, 4b cuts off the lower end part along the bottom face of non-overflow part 10a, 10b beforehand.
In addition, about the steel plate panel arrange | positioned at the upper end of curved wall part 4a, 4b, the length of the circular arc of a curved part is shorter than other steel plate panels, and you may manufacture beforehand a thing with low height. That is, as long as the steel plate panel has a shape that fills the gap between the upper end portions of the non-overflow portions 10a and 10b that are generated by tilting and stacking the steel plate panels, any form may be used. Thereby, the cutting of the steel plate panel at the upper end can be omitted.
Further, the ground is dug in accordance with the protrusion of the steel plate panel arranged at the lower end of the curved wall portions 4a and 4b to the bottom surface of the non-overflow portions 10a and 10b, and the steel plate panel is embedded in the formed groove to form a foundation. Concrete 11a, 11b may be placed. Thereby, the cutting of the steel plate panel at the lower end can be omitted.

Next, the filling materials 5a and 5b are filled in the space surrounded by the walls (step S3). As described above, the filling materials 5a and 5b are soil cement obtained by adding cement and cement milk to the on-site generated earth and sand generated at the construction site of the sabo dam 100 and kneading them.
After the filling materials 5a and 5b are solidified, concrete is placed on the top end surfaces (portions not covered by the walls) as the top end protection members 6a and 6b (step S4). Here, the top edge protection members 6a and 6b may be cast concrete on site or may be connected to each other by spreading concrete panels prepared in advance.
Non-overflow portions 10a and 10b are completed by steps S1 to S4.
Next, the foundation primary concrete 21 is laid between the non-overflow portion 10a and the non-overflow portion 10b (step S5).
Next, the fence body 22 in which concrete columns or steel columns are assembled in a lattice shape is installed on the primary primary concrete 21 (step S6).
Next, the foundation secondary concrete 21 is driven to a predetermined height so as to bury the lower portion of the fence body 22 (step S7).
Through steps S5 to S7, the transmission unit 20 is completed.
In addition, you may construct the permeation | transmission part 20 not after the construction of the non-overflow parts 10a and 10b but before construction of the non-overflow parts 10a and 10b simultaneously with the construction of the non-overflow parts 10a and 10b.

[Action and effect of sabo dam]
According to the sabo dam 100 having the above-described structure, the slopes F1 and F4 are formed on the upstream wall portions 1a and 1b and the curved wall portions 4a and 4b, so that the earth and sand contained in the debris flow is shown in FIG. When the water 50 collides with the trapezoidal non-overflow portions 10a and 10b having a cross section ABCD, the water 50 accumulates on the slopes F1 and F4. The soil / water 50 deposited on the slopes F1 and F4 acts on the slopes F1 and F4 by the weight, thereby increasing the weight of the non-overflow portions 10a and 10b. It can be regarded as a non-overflow part of the shape.
Therefore, by providing the slopes F1 and F4, the earth and sand 50 can be used as a part of the non-overflow portions 10a and 10b, and the strength calculated from the cross sections of the non-overflow portions 10a and 10b to be constructed. The above sabo dam 100 can be constructed. Therefore, the strength of the sabo dam 100 can be improved and the cost can be reduced. Moreover, the optimal sabo dam 100 can be constructed according to the environment of the installation location.
Further, slopes can be provided on the non-overflow portions 10 a and 10 b in accordance with the transmission portion 20.
Further, the presence of the curved walls 4a and 4b can alleviate the impact force on the sabo dam 100 due to debris flow or the like, and can suppress the breakage of the sabo dam 100.
Further, in order to increase the strength of the sabo dam 100, it is not necessary to make the slope of the downstream walls 2a, 2b gentle, so that the non-overflow portions 10a, 10b are not deeply embedded, and the sabo dam There is no need to increase 100, and there is no need to change the design of the root.
Moreover, construction management can be made easy by forming each wall part with a steel plate panel altogether.
Moreover, the cost concerning construction can be reduced compared with the case where concrete is used by constructing a wall part with a steel plate panel and making the filling materials 5a and 5b into soil cement. Furthermore, by not using concrete, the installation and removal of the formwork for placing concrete and the curing after placing concrete are eliminated, and the construction period can be shortened.

1a, 1b Upstream wall part 2a, 2b Downstream wall part 3a, 3b Side wall part 4a, 4b Curved wall part 5a, 5b Filling material 6a, 6b Top end protection material 10a, 10b Non-overflow part 20 Permeation part 100 Sabo dam

Claims (7)

A construction method of a sabo dam provided with a pair of non-overflow portions that prevent overflow of a debris flow flowing from the upstream side, and a permeation portion that is provided between the non-overflow portions and transmits running water,
Building the upstream wall,
Constructing the downstream wall,
Constructing a side wall portion continuous with the downstream wall portion on the transmission portion side;
Constructing a curved wall part that is continuous with the upstream wall part and the side wall part, and at least part of which is formed in a curved shape;
Filling the filling material into the space surrounded by these walls,
A step of capturing a debris between the pair of non-overflow portions and constructing a permeation portion that transmits the running water;
Forming a slope that slopes downward toward the upstream side from the upper end toward the lower end on the upstream wall portion and the curved wall portion; and
A method for constructing a sabo dam, characterized by comprising:   The construction method of a sabo dam according to claim 1, wherein the curved wall portion is constructed by a plurality of steel plate panels. The steel plate panel is formed so that the upper edge and the lower edge are parallel, and the cross section in the direction perpendicular to the slope of the curved portion is an arc having a central angle of 90 °,
The construction method of the sabo dam according to claim 2, wherein the curved wall portion is constructed by stacking so that an upper edge and a lower edge of the steel plate panel are perpendicular to the slope.   The construction method of the sabo dam according to claim 3, wherein an upper end of a steel plate panel arranged at an upper end of the curved wall portion is cut along a top end of the non-overflow portion.   The construction of the sabo dam according to claim 3, wherein the steel plate panel disposed at the upper end of the curved wall portion has a shorter arc length and a lower height than the other steel plate panels. Method.   The construction method of the sabo dam according to any one of claims 3 to 5, wherein a lower end of a steel plate panel disposed at a lower end of the curved wall portion is cut along a bottom surface of the non-overflow portion. .   6. The ground is dug according to the protrusion of the steel plate panel arranged at the lower end of the curved wall portion to the bottom surface of the non-overflow portion, according to claim 3. Sabo dam construction method.