JP2016141945A - Dam repair method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a load of a damaged segment repair work.SOLUTION: A dam (1) comprises: an upstream wall part (3), which is constructed by connecting multiple segments (31) and disposed so as to face the upstream side of a river; and a downstream wall part (4), which is constructed by connecting the multiple segments (31) and disposed so as to face the downstream side of the river. In a dam repair method, a repair material (6) is fit so as to cover a damaged part of a damaged segment (31).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for repairing a dam provided in a river.

Sabo dams are known to prevent disasters caused by debris flows. The sabo dam includes an upstream wall portion provided to face the upstream side of the river, and a downstream wall portion provided to face the downstream side of the river. Some sabo dams have an upstream wall constructed by connecting a plurality of steel sheet piles. In the space formed between both wall portions, soil cement is placed as a filling material.
The upstream wall portion is configured by joining steel sheet piles having grip-shaped slide joint portions on both side edges and connecting the slide joint portions to each other. The steel sheet pile is inserted between two steel sheet piles that are spaced apart from each other, and the steel sheet pile is further erected from above while joining the slide joint portion (see, for example, Patent Document 1).
In the connection between the steel sheet piles as in Patent Document 1, the connection in the lateral direction with the adjacent steel sheet pile is strong. However, the steel sheet pile adjacent in the vertical direction is simply that the upper and lower end surfaces of the adjacent steel sheet piles are in contact with each other, and the connection in the vertical direction with the adjacent steel sheet pile is weak. Therefore, for example, when an impact that pushes the steel sheet pile upward from below due to the occurrence of a debris flow is applied to the steel sheet pile, the steel sheet pile may move upward. This movement causes a gap between the steel sheet piles adjacent in the vertical direction. As a result, the filling material is exposed from this gap, and in some cases, the filling material may flow out, so that not only the moved steel sheet pile is removed and replaced with a new steel sheet pile, but also In some cases, repairs were necessary.

  In order to solve such a problem, it is effective to connect the panels (segments) constituting the upstream wall surface member with bolts on the upper and lower sides and the four sides on the left and right sides (for example, see Patent Document 2). This configuration can prevent the panel from moving in the vertical direction even when an impact is applied to the panel from the bottom to the top, and is also effective in improving the strength of the dam.

Japanese Patent No. 4060135 JP 2012-092583 A

  However, in the panel (segment) in Patent Document 2, although the problem of movement due to the impact of debris flow and the accompanying exposure of the filling material is solved, the panel is free of falling objects such as rocks and driftwood contained in the debris flow. The collision may cause damage such as deformation and breakage. If a panel is damaged, it must be removed and replaced, but adjacent panels are fastened by bolts and nuts inside the dam, so the panel must be removed by cutting this fastening site from the outside of the dam. did not become. Therefore, the repair work is extremely time-consuming.

  Then, this invention is made | formed in view of the said subject, and it aims at providing the repair method of the dam which can reduce the burden of repair work of the damaged segment.

  In order to achieve the above object, the present invention comprises a plurality of segments connected to each other, an upstream wall provided so as to face the upstream side of the river, and a plurality of segments connected to each other. A dam repair method comprising a downstream wall provided to face the downstream side, wherein a repair member is attached so as to cover a damaged portion of the damaged segment.

  Moreover, when the material of the said repair member and the said segment is the same, it is preferable that the cross-sectional area of the said repair member is more than the cross-sectional area of the said segment.

  Further, when the material of the repair member and the segment are different from each other, the value of the cross-sectional area of the repair member is the ratio of the shear strength per unit area of the segment to the shear strength per unit area of the repair member, It is preferable that the value is not less than a value calculated by multiplying the cross-sectional area of the segment.

  Further, the damaged portion of the damaged segment is a concave portion recessed toward the inside of the dam, and is formed at least between the concave portion and the repair member after the repair member is attached to the damaged segment. It is preferable to fill the space with a reinforcing material.

  Moreover, it is preferable that the filling material is filled in the space formed between the upstream wall portion and the downstream wall portion, and the strength of the reinforcing material is equal to or higher than the strength of the filling material.

  The reinforcing material is preferably mortar.

  Moreover, it is preferable to attach the repair member to the damaged segment by welding.

  Moreover, it is preferable that the said segment has a flat part and the said repair member formed in flat form is joined to the said flat part.

  In addition, the segment includes a plate that receives what flows from the upstream of the river, and a flange that is provided on the outer edge of the plate and has a hole through which a fastener that connects adjacent segments is inserted. The segment is preferably connected to a segment adjacent to the segment by the fastener through the hole of the flange.

  According to the present invention, the burden of repairing damaged segments can be reduced.

It is the perspective view which looked at a part of dam. It is the perspective view which looked at the upstream wall part which has the damaged segment of a dam from the dam outer side, and shows the state before attaching a repair member. It is the perspective view which looked at the upstream wall part which has the damaged segment of a dam from the dam outer side, and shows the state after attaching a repair member. 4A is a cross-sectional view of the upstream wall portion shown in FIG. 3, FIG. 4A is a cross-sectional view taken along the line II of FIG. 3, and FIG. 4B is a line taken along the line II-II of FIG. It is a longitudinal cross-sectional view. It is a figure which shows the relationship between the cross-sectional area of a segment, and the cross-sectional area which a repair member requires.

  Preferred embodiments of the present invention will be described with reference to the drawings. The following embodiment is merely an example, and various embodiments can be employed within the scope of the present invention.

<Configuration of dam>
FIG. 1 is a perspective view of an impervious sabo dam 1 provided in a river, and a part of the dam 1 is viewed in cross section.
As shown in FIG. 1, the dam 1 includes a foundation portion 2, an upstream wall portion 3, a downstream wall portion 4, and a filling material 5. The sleeve of the dam 1 is connected to the river bank.

(Basic part)
The foundation 2 is made of concrete and is provided at the bottom of the river along a direction perpendicular to the direction of flow of the river (the width direction of the river). Two base portions 2 are provided, and are arranged at predetermined intervals on the upstream side and the downstream side.
The upper surface of each base portion 2 is formed in a planar shape, the upstream wall portion 3 is provided on the upper surface of the upstream base portion 2, and the downstream wall portion 4 is provided on the upper surface of the downstream base portion 2. ing.

(Upstream wall)
FIG. 2 is a perspective view of the partially damaged upstream wall 3 viewed from the outside of the dam 1, and shows a part of the upstream wall 3 in an enlarged manner. Since the upstream wall part 3 is provided on the upper surface of the upstream base part 2, the upstream wall part 3 is provided to face the upstream side of the river. Here, FIG. 2 shows a state in which a damaged portion is generated in a part of the segment 31 due to a collision of a falling material such as a rock included in the debris flow, and a repair member 6 (described later) for repairing the damaged portion is as follows. It is in the state before installation.

The upstream wall portion 3 is configured by connecting a plurality of steel segments 31 with fasteners 32 (see FIGS. 4A and 4B) inside the dam 1, and reinforcing members such as reinforcing bars (FIG. It is reinforced from the inside of the dam 1 by not shown).
The segment 31 includes a plate 33 that receives a flowing material flowing from the upstream of the river, for example, rock, wood, and the like, and a flange 34 that is erected on each edge of the plate 33 (FIG. 2). reference).
The plate 33 is configured in a rectangular shape in plan view. For example, the corrugated portion 33a formed by curving a steel plate into a corrugated shape and the flat portions formed at both side ends in the short side direction of the corrugated portion 33a. Part 33b. Here, the plate 33 is not limited to a corrugated plate, and may be a flat steel plate or a steel plate with curved sides. The plate 33 shown in FIG. 2 to FIG. 4 has a wave shape in which both side ends in the short side direction are formed in a flat plate shape, and other portions undulate in the thickness direction of the plate 33 along the short side direction. Is formed. As shown in FIG. 2, the damaged portion of some segments 31 is a recess 33 c formed by the plate 33 being recessed toward the inside of the dam 1 due to the collision of the flowing-down object.
The flange 34 includes, for example, upper and lower flanges 34a formed by welding separate steel plates to both end portions in the long side direction of the plate 33, and both side end portions in the short side direction of the plate 33. It has a side flange 34b (see FIG. 4B) that is bent and formed integrally with the plate 33. That is, in one segment 31, one plate 33 and four flanges 34 are provided.
The side flange 34b is formed integrally with the plate 33, but may be formed separately from the plate 33 and fixed to the side of the plate 33 by welding or the like.

As shown in FIG. 4A, the flat portion 33 b is formed outside the dam 1 in the thickness direction of the plate 33.
The adjacent flanges 34a and 34b in one segment 31 are perpendicular to each other, and the opposing flanges 34a and 34a (34b and 34b) are parallel to each other. Has been placed. Each flange 34 is formed with a plurality of holes 34c for inserting fasteners 32 that connect and fix adjacent segments 31 to each other. The holes 34c are formed so that the positions of the holes 34c match even when the segments 31 are stacked. In a state where the adjacent segments 31 are alternately arranged in the vertical direction (staggered), the holes 34c of both the adjacent segments 31 are in a state of being aligned on the same axis.
In addition, you may affix the waterproofing tape (not shown) as a sealing member between the adjacent segments 31. FIG.

  The fastener 32 connects adjacent segments 31 to each other. The fastener 32 includes a bolt 32a and a nut 32b (see FIGS. 4A and 4B) that is screwed into the bolt 32a. The segments 31 are connected to each other by inserting the bolts 32a through the holes 34c of the both connected segments 31 and tightening the nuts 31b on the segment 31 side opposite to the inserted side.

(Downstream wall)
As shown in FIG. 1, since the downstream wall part 4 is provided in the upper surface of the downstream foundation part 2, the downstream wall part 4 is provided so that the downstream of a river may be opposed.
The downstream wall portion 4 is configured by connecting a plurality of segments 41 with fasteners including bolts and nuts. The adjacent segments 41 are arranged alternately (staggered) in the vertical direction so that the upper and lower edges of the adjacent segments 41 do not have the same height. The segment 41 is composed of a concrete panel. A support member and a reinforcing member (not shown) are connected to the segment 41 in the vicinity of the base portion 2.
In addition, you may affix the waterproofing tape (not shown) as a sealing member between the adjacent segments 41. FIG. Moreover, you may comprise the structure of the downstream wall part 4 by connecting a some steel segment similarly to the upstream wall part 3. FIG.

(Filling material)
As shown in FIG. 1, the filling material 5 is placed in a space S between the upstream wall portion 3 and the downstream wall portion 4 and has fluidity.
Specifically, the filling material 5 is a soil cement prepared by mixing cement and water with locally generated soil on the site where the dam 1 is installed. The soil cement used here is not asked about the presence or absence of slump. That is, the dam 1 is a dam that can be handled regardless of whether the soil cement has fluidity. Therefore, whatever the nature of the soil generated locally, it can be constructed as a dam by adjusting the amount of cement and water.
The strength (compressive strength) of the filling material 5 is preferably 3 N / mm ² or more.

<How to repair the dam>
Next, the repair method of the said dam 1, specifically the upstream wall part 3 in which the damaged part (concave part 33c) was formed by the collision of the rocks etc. which are contained in the debris flow is demonstrated.
The recess 33c is repaired by attaching the repair member 6 to the damaged segment 31 so as to cover the recess 33c, and filling the reinforcing material 7 between the damaged segment 31 and the repair member 6.

(Process 1: Attaching repair members)
As shown in FIG. 2, one segment 31 of the upstream wall portion 3 has a recess 33 c that is recessed toward the inside of the dam 1, particularly due to damage of a part of the corrugated portion 33 a of the plate 33. The concave portion 33c is mainly formed by a river flowing material or the like colliding with the segment 31, and in the worst case, the bottom surface of the concave portion 33c may be broken and the filling material 5 may be exposed. The repair member 6 is attached to the segment 31 from the outside of the dam 1 so as to cover the recess 33c when the segment 31 is damaged.

FIG. 3 is a view showing a state in which the repair member 6 is attached to the segment 31 having the recess 33c. As shown in FIG. 3, the repair member 6 is attached not only to cover the recess 33c but also to cover the entire segment 31 having the recess 33c.
FIGS. 4A and 4B are diagrams showing the attachment structure of the repair member 6 to the segment 31. FIG.
FIG. 4A is a cross-sectional view taken along the line II of FIG. As shown in FIG. 4A, the repair member 6 is attached to the segment 31 on the long side in the flat portion 33 b of the plate 33 having the concave portion 33 c and the flat portion 33 b of the adjacent plate 33. That is, both ends of the repair member 6 in the short side direction straddle the seam with the adjacent segment 31 in the width direction of the segment 31.
FIG. 4B is a cross-sectional view taken along the line II-II in FIG. As shown in FIG. 4B, the repair member 6 is attached to the segment 31 on the short side, the segment 31 having the concave portion 33 c, and the upper side of the segment 31 adjacent on the end side in the longitudinal direction of the segment 31. And on the surface of the lower flange 34a exposed to the outside of the dam 1. That is, both ends of the repair member 6 in the long side direction straddle the joints of the adjacent segments 31 on the end side in the longitudinal direction of the segment 31.
4A and 4B illustrate a state in which the repair member 6 straddles the joint between the segments 31. However, it is also possible to attach the repair member 6 using only the surface of the flat portion 33b of the plate 33 having the recess 33c and the flange 34a exposed to the outside of the dam 1 without straddling the seam. .
The repair member 6 is preferably attached to the segment 31 by joining the repair member 6 and the segment 31 by a known welding method over the entire circumference of the repair member 6 at the site where the dam 1 is installed.

(Process 2: Filling with reinforcing material)
After the repair member 6 is attached to the segment 31, the reinforcing material 7 is filled between the repair member 6 and the segment 31. Thus, as shown in FIGS. 4A and 4B, including the space between the repair member 6 and the wave-shaped portion 33a of the plate 33 that is not deformed, the space between the repair member 6 and the recess 33c. The space is completely filled with the reinforcing material 7.
As the reinforcing material 7 to be used, for example, mortar is used. The strength (compressive strength) of the mortar is preferably about 3 N / mm ² or more, for example, equal to or higher than the strength of the filling material 5. The blending of mortar is based on “Japanese Industrial Standard JIS R 5201 Cement Physical Test Method”.

As shown in FIGS. 2 and 3, a hole 61 for filling the reinforcing material 7 is formed in the repair member 6. The formation position of the hole 61 is not particularly limited, but in the attached state of the repair member 6, the hole 61 may be formed on the upper side of the repair member 6 in the long side direction. In the short side direction, the corrugated portion 33 a has a concave shape. It is good to be formed in the position which opposes a part.
When repairing the dam 1, the repair member 6 having a cross-sectional area larger than that capable of reinforcing the damaged segment 31 is selected according to the cross-sectional area of the segment 31. Specifically, the cross-sectional area of the repair member 6 is preferably set to a size such that the repair member 6 has a shear strength equal to or higher than the shear strength of the segment 31. The cross-sectional area of the repair member 6 is determined in consideration of the material of the segment 31 and the repair member 6.
Here, the cross-sectional area of the repair member 6 is an area (cross-sectional area) of a cross section obtained by cutting the repair member 6 along the width direction of the repair member 6, that is, the short side direction. The cross-sectional area (cross-sectional area) obtained by cutting the plate 33 and the side flange 34b along the width direction, that is, the short side direction.
If the repair member 6 has a cross-sectional area having a shear strength equal to or higher than the shear strength of the segment 31, the cross-sectional shape of the repair member 6 is not particularly limited. As shown in FIGS. 2 to 4, for example, the cross-sectional shape may be a flat plate shape or a wave shape. Furthermore, a steel plate whose surface protrudes outside the dam 1 may be used as the repair member 6 from the viewpoint of sufficiently securing a space for filling the reinforcing material 7 between the repair member 6 and the segment 31.
The material of the repair member 6 is not particularly limited as long as the repair member 6 has a cross-sectional area having a shear strength equal to or higher than the shear strength of the segment 31.

<Determination of cross-sectional area of repair member>
Next, how to determine the cross-sectional area of the repair member 6 will be described.
(When the material of the segment and repair member is the same)
Since the repair member 6 has a shear strength equal to or higher than that of the segment 31, the cross-sectional area of the repair member 6 is set to be equal to or larger than the cross-sectional area of the segment 31.

(When segment and repair material are different)
Since the repair member 6 has a shear strength equal to or higher than that of the segment 31, the cross-sectional area required for the repair member 6 is the shear strength calculated from the respective yield strengths of the segment 31 and the repair member 6. It is calculated based on the ratio of the values and the cross-sectional area of the segment 31.
Specifically, the value of the yield strength determined by the material of the segment 31 is calculated by dividing the value of the yield strength determined by the material of the repair member 6 by √3 with respect to the value of the shear strength calculated by dividing by √3. The ratio of the shear strength value is multiplied by the value of the cross-sectional area of the segment 31 to be repaired to calculate the cross-sectional area required for the repair member 6 to have a shear strength equal to or higher than that of the segment 31.

<Action, effect>
According to the repair method of the dam 1 as described above, the repair member 6 is attached to the segment 31 so as to cover the recessed portion 33c (damaged portion) of the damaged segment 31 of the upstream wall portion 3. The dam 1 can be repaired without removing the damaged segment 31 from the upstream wall 3. Therefore, it is only necessary to repair the damaged segment 31, and it is possible to reduce the burden of repair work on the upstream wall 3, reduce the construction work period, and reduce the cost.
Since the cross-sectional area of the repair member 6 is set to a size greater than the cross-sectional area necessary for obtaining the shear strength greater than the shear strength of the segment 31, the upstream wall 3 after the repair is compared with that before the repair. The strength of the dam 1 can be increased, and at the same time, the dam 1 can be reinforced.
By filling the space between the segment 31 and the repair member 6 with the reinforcing material 7, the strength of the upstream wall portion 3 can be further increased as compared with the case where only the repair member 6 is attached.
By using a known mortar as the reinforcing material 7, the cost for the reinforcing material 7 can be suppressed. Moreover, the intensity | strength in the whole dam 1 after repair improves by making the intensity | strength of mortar more than the intensity | strength of the filling material 5. FIG.
Since the repair member 6 is attached by welding, simple and quick attachment can be achieved at the installation site of the dam 1. Therefore, it is possible to shorten the work time for repair and reduce the work load. Further, since the repair member 6 is welded to the flat portion of the segment 31 and the upper and lower flanges 34 a and 34 a, it is possible to prevent the reinforcing material 7 (liquid mortar) from leaking between the repair member 6 and the segment 31. You can also.
Since the adjacent segments 31 are connected to each other through bolts 32a and nuts 32b on the four sides, the segments 31 are moved by the impact due to the collision of the falling material, etc., so that the segments 31 are adjacent in the longitudinal direction. There will be no gaps. Therefore, exposure and outflow of the filling material 5 can be prevented, and labor for repairing the filling material 5 can be saved. Since only the plate 33 of the segment 31 needs to be repaired, the repair area can be reduced and workability can be improved. Further, by reducing the repair area, it is possible to reduce the amount of materials used for the repair member 6 and the reinforcing material 7 and to reduce the cost.

<Others>
The present invention is not limited to the above embodiment. In the above embodiment, the repair method for the upstream wall portion has been described. However, when the downstream wall portion is configured by the plurality of segments 31 like the upstream wall portion, the repair method is downstream when the downstream wall portion is damaged. It can also be applied to walls.

Specific examples of the present invention will be described below, but the present invention is not particularly limited to these examples.
FIG. 5 is a diagram illustrating a relationship between the configuration of the segment 31 and the configuration of the repair member 6 that reinforces the segment 31, which are different in material.

In each of the following Examples 1 to 4, a corrugated steel sheet having a material of steel (SS330), a yield strength of 205 N / mm ² and a shear strength of 118 N / mm ² was used as the segment 31.
Further, in each of the following Examples 1 to 4, a flat steel plate having a material of steel (SS400), a yield strength of 235 N / mm ² and a shear strength of 136 N / mm ² was used as the repair member 6.

In each Example 1-4, the cross-sectional area required for the repair member 6 used for repair is the cross-sectional area of the segment 31 of each Example 1-4, the shear strength of the segment 31 with respect to the shear strength of the repair member 6 ratio, i.e., calculated by multiplying the value obtained by dividing the 118 N / mm ² at 136N / mm ^2.

<Example 1>
When the segment 31 having a thickness of 2.7 mm and a cross-sectional area of 39.76 cm ² / m is used, the cross-sectional area required for the repair member 6 is the shear strength ratio of the cross-sectional area of the segment 31 of 39.76 cm ² / m. A value obtained by multiplying ((118 N / mm ² ) / (136 N / mm ² ) ≈0.868), that is, 34.50 cm ² / m.
Therefore, in Example 1, the repair member 6 has a higher shear strength than the segment 31 by using the flat repair member 6 having a thickness of 4.0 mm, a width of 1000 mm, and a cross-sectional area of 40 cm ² / m. Will have.

<Example 2>
When the segment 31 having a thickness of 3.2 mm and a cross-sectional area of 47.12 cm ² / m is used, the cross-sectional area required for the repair member 6 is the above-described shear strength of the cross-sectional area of the segment 31 of 47.12 cm ² / m. A value obtained by multiplying by the ratio 0.868, that is, 40.88 cm ² / m.
Therefore, in Example 2, the repair member 6 has a higher shear strength than the segment 31 by using the flat repair member 6 having a thickness of 4.5 mm, a width of 1000 mm, and a cross-sectional area of 45 cm ² / m. Will have.

<Example 3>
When the segment 31 having a thickness of 4.0 mm and a cross-sectional area of 58.86 cm ² / m is used, the cross-sectional area required for the repair member 6 is the above-described shear strength of the cross-sectional area of the segment 31 of 58.86 cm ² / m. A value obtained by multiplying the ratio by 0.868, that is, 51.07 cm ² / m.
Therefore, in Example 3, the repair member 6 has a higher shear strength than the segment 31 by using the flat repair member 6 having a thickness of 6.0 mm, a width of 1000 mm, and a cross-sectional area of 60 cm ² / m. Will have.

<Example 4>
When the segment 31 having a thickness of 4.5 mm and a cross-sectional area of 66.22 cm ² / m is used, the cross-sectional area required for the repair member 6 is the above-described shear strength of the cross-sectional area of the segment 31 of 66.22 cm ² / m. A value obtained by multiplying by the ratio 0.868, that is, 57.46 cm ² / m.
Therefore, in Example 4, the repair member 6 has a higher shear strength than the segment 31 by using the flat repair member 6 having a thickness of 6.0 mm, a width of 1000 mm, and a cross-sectional area of 60 cm ² / m. Will have.

DESCRIPTION OF SYMBOLS 1 Barrage 3 Upstream wall part 4 Downstream wall part 5 Filling material 6 Repair member 7 Reinforcement material 31 Segment 32 Fastening tool 32a Bolt 32b Nut 33 Plate 33a Wave-shaped part 33b Flat part 33c Concave part 34 Flange 34a Upper side flange, lower side flange 34b side Side flange 34c Hole 41 Segment 61 Hole S Space

Claims (9)

A plurality of segments connected to each other, an upstream wall provided to face the upstream side of the river;
A plurality of segments connected to each other, and a downstream wall portion provided so as to face the downstream side of a river, and a repair method for a dam,
A repair method for a dam, wherein a repair member is attached so as to cover a damaged portion of the damaged segment.   2. The dam repair method according to claim 1, wherein when the material of the repair member and the segment is the same, a cross-sectional area of the repair member is equal to or larger than a cross-sectional area of the segment.   When the material of the repair member and the segment are different from each other, the value of the cross-sectional area of the repair member is the ratio of the shear strength per unit area of the segment to the shear strength per unit area of the repair member. The dam repair method according to claim 1, wherein the dam repair value is equal to or greater than a value calculated by multiplying the cross-sectional area of the dam. The damaged part of the damaged segment is a recess recessed toward the inside of the dam,
The reinforcing material is filled in at least a space formed between the concave portion and the repair member after the repair member is attached to the damaged segment. Repair method of the dam as described in the item. A filling material is filled in a space formed between the upstream wall portion and the downstream wall portion,
The dam repair method according to claim 4, wherein the strength of the reinforcing material is greater than or equal to the strength of the filling material.   The dam repair method according to claim 4, wherein the reinforcing material is mortar.   The dam repair method according to any one of claims 1 to 6, wherein the repair member is attached to the damaged segment by welding. The segment has a flat portion;
The dam repair method according to claim 7, wherein the repair member formed in a flat plate shape is joined to the flat portion. The segment receives a plate that flows from upstream of the river;
A flange that is erected on the outer edge of the plate and has a hole that is inserted through a fastener that connects adjacent segments;
The dam according to any one of claims 1 to 8, wherein the segment is connected to a segment adjacent to the segment by the fastener through the hole of the flange. Repair method.

Images