JP7183816B2 - Embankment reinforcement structure - Google Patents

Description

The present invention relates to a reinforcement structure for a bank body.

In recent years, there have been many breaches of river levees and reservoir levees due to large-scale earthquakes, and several large-scale earthquakes are expected to occur. is increasing.

In view of this background, techniques for reinforcing embankments (embankment bodies) using steel sheet piles have been proposed (for example, see Patent Documents 1 and 2).
In the seismic performance reinforcing structure of the embankment described in Patent Document 1, reinforcing plate-like bodies formed of steel sheet piles in two rows and columns in the longitudinal direction of the almost central part of the embankment such as an earthfill dam or a reservoir are installed. It has a double coffer structure in which the upper ends of both reinforcing plate-shaped bodies are embedded and connected by a connecting member at predetermined intervals.

In addition, in the embankment reinforcement structure described in Patent Document 2, a steel wall formed of steel sheet piles continuous in the extension direction of the embankment near the shoulder on the outer side of the embankment and whose lower end reaches the support layer of the ground. is provided, and in the vicinity of the slope shoulder on the inner side of the embankment, discretely arranged anchorages are provided, and the steel wall and the anchorage are connected to each other by a tie material near the crest of the embankment. .

JP-A-2003-321826 JP 2013-14962 A

By the way, ``Trans.
127-137 (2002.4), ``Causes of Destruction of Agricultural Ponds by Heavy Rain and Characteristics of Damage'', it is said that there are about 200,000 to 250,000 agricultural reservoirs nationwide. It is a valuable water resource not only for agriculture but also for the region. However, there are many ponds because they were built long ago and have deteriorated, and there are concerns about damage to the ponds during heavy rains. Damage to reservoirs includes damage to the embankment due to slips and erosion, leakage of water from the embankment and foundation, and damage to incidental structures. It's becoming
Due to recent heavy rain/earthquake disasters, damage caused by the collapse of dams of reservoirs has occurred nationwide, and there are more than 200,000 to 250,000 locations scattered throughout the country, so reinforcement of dams has become an urgent issue. ing.
As a levee reinforcement construction method using steel sheet piles, the steel sheet pile double cofferdam construction method has already been established, and has been adopted as a permanent structure for coastal levees. On the other hand, since a fixed amount of water is constantly stored in the irrigation levee (bank body) for agricultural purposes, it is necessary to take countermeasures that take into consideration the unbalanced water pressure on the levee body, which always acts.

In the conventional embankment reinforcement structures described in Patent Document 1 and Patent Literature 2 described above, the embankment (embankment body) is regarded as a linearly elongated uniform structure, and the extension direction (extending direction) of the embankment is perpendicular to the extension direction (extending direction) of the embankment. It is mainly to apply a reinforcement construction method that devises the arrangement of reinforcing bodies on a two-dimensional cross section, or to install reinforcing structures discretely within the range inside the extension direction of the embankment body as a linear structure. there were.
However, if a structure is installed only inside the embankment to resist the water pressure generated in the event of a disaster, etc., the reinforcing structure becomes large, which increases the construction cost and construction period.
Reservoirs are classified into valley ponds and saucer ponds according to their shape. In the case of valley ponds, where the surrounding ground is surrounded by bedrock and hard strata, the construction method of installing steel sheet piles inside the levee body is not effective against water pressure. In order to set the bottom end of the steel sheet pile in a hard layer to resist, a special construction machine such as a crush piler is required to crush the ground. In the crush piler, the cost of machine damage is high, which puts pressure on construction costs, and the speed of construction slows down because the ground is crushed. In addition, since it is a large heavy machine, it may not be possible to bring it into a narrow area such as a mountainous area.

The present invention has been made in view of the above-mentioned circumstances, and can shorten the construction cost and construction period compared to the conventional method. An object of the present invention is to provide a reinforcement structure for a bank body that can prevent collapse of the bank body.

In order to achieve the above object, a bank body reinforcement structure of the present invention is a bank body reinforcement structure for reinforcing the bank body of a valley pond formed by blocking a valley with a bank body,
A steel wall is installed inside the bank body along the extending direction of the bank body, an anchor part is installed in the natural ground around the valley pond, and the anchor part is connected to the steel wall. It is characterized by

Here, the bank of the valley pond is formed longer than the length in the width direction of the valley pond at the portion that dams the water stored in the valley pond, and the length of the bank in the longitudinal direction (extending direction) of the bank is projects laterally from the valley pond in plan view. The steel wall installed inside the bank is formed continuously from one longitudinal end to the other longitudinal end of the bank in plan view. Therefore, the anchors are installed on the natural ground near one end of the embankment and the natural ground near the other end, one anchor is connected to one end of the steel wall, and the other anchor is made of steel. It is preferably connected to the other end of the plate wall.

Moreover, as the steel wall, a steel sheet pile wall formed by connecting a plurality of steel sheet piles is suitably used, but it is not limited to this. For example, a steel pipe sheet pile wall formed by connecting a plurality of steel pipe sheet piles, a steel wall formed by connecting a plurality of steel sheet piles and steel pipe sheet piles, or the like may be used.

In the present invention, since the anchor part installed in the natural ground around the valley pond is connected to the steel wall installed inside the bank, the bank is made of steel using the strength of the natural ground. Can be reinforced by walls and anchors. Therefore, when the amount of water stored in the valley pond increases, it is possible to sufficiently resist the water pressure acting on the levee body and prevent the levee body from collapsing.
In addition, steel walls and anchors can be used to fix the boundary surface between the ground and the embankment body, which is the starting point of embankment collapse and has different soil properties that easily become water paths, thereby reducing the risk of embankment body collapse. can be reduced.

Moreover, the said structure of this invention WHEREIN: The said anchor part may be equipped with the support member installed in the said natural ground, and the connection member which connects this support member and the said steel wall.

Examples of the supporting member include, but are not limited to, piles (steel pipe piles and concrete piles), steel sheet piles, and rock bolts installed in the ground.
In addition, when steel sheet piles are used as supporting members, a plurality of steel sheet piles are arranged so that the connecting members are linear in the direction away from the steel wall, and the connecting parts with the connecting members are aligned. , may be installed at predetermined intervals in the thickness direction of the steel sheet pile (direction perpendicular to the steel wall).
Moreover, although a tie-rod is mentioned as said connection member, it is not restricted to this. For example, any material having a predetermined tensile strength such as a PC steel bar or a PC steel wire may be used.

According to this configuration, since the anchor portion includes the supporting member and the connecting member, the supporting member is installed in the natural ground, and the supporting member is connected to the steel wall by the connecting member. Compared to the case where the lower end of the wall is driven into the support layer over the entire length of the bank, construction is easier, and the rigidity required for the steel wall to resist increases in water pressure can be reduced, making it economical. It is possible to realize a suitable reinforcement method.

Moreover, in the configuration of the present invention, the anchor portion may have a buttress wall extending in a direction intersecting the steel wall, and the buttress wall may be connected to the steel wall.

Here, "intersection" means not only the case where the buttress is orthogonal to the steel wall, but also the case where the buttress is at a predetermined angle (for example, 45° or more, 90°) with respect to the steel wall (extending direction). less than) and crosses at an angle.

According to this configuration, since the buttress extending in the direction intersecting the steel wall is connected to the steel wall, the frictional force between the buttress and the natural ground also acts on the bank. Able to resist water pressure. Therefore, it can sufficiently resist the water pressure acting on the cut-off wall.

Further, in the above configuration of the present invention, the steel wall installed inside the bank has an upper end at a height position equal to the crown of the bank, and is positioned below the bank. It may be embedded to the top of the layer or bedrock layer.

Here, when the steel wall is embedded up to the upper surface of the bearing layer or bedrock layer, if there is a soft layer directly below the embankment and there is a bearing layer or bedrock layer directly below it, the steel wall is It means that the lower end of the steel wall is in contact with or close to the upper surface of the support layer or bedrock layer while penetrating the soft layer. means that the lower end of the steel wall installed inside the is in contact with or close to the upper surface of the support layer or bedrock layer.

According to this configuration, the upper end of the steel wall is at the same height as the crest of the levee body, and the steel wall is embedded up to the upper surface of the support layer or bedrock layer located below the levee body. Therefore, it is possible to prevent the occurrence of a water path penetrating the bank from the valley pond side and a water path penetrating the weak layer directly under the bank from the valley pond side, so that seepage failure of the bank can be suppressed.
In addition, when driving (embedding) a steel wall into the support layer or bedrock layer, a special construction machine such as a crush piler that crushes the ground is required. By stopping, construction can be performed with a normal construction machine, and construction costs can be suppressed.

Further, in the configuration of the present invention, a structure extending in the width direction of the bank is provided inside the bank, and a part of the lower end of the steel wall does not reach the structure. good too.

Here, the structure provided inside the embankment includes a bottom gutter, but is not limited to this.
In addition, when the steel wall is composed of a steel sheet pile wall, the lower end of the steel sheet pile positioned above the structure among the plurality of steel sheet piles constituting the steel sheet pile wall reaches the structure. It doesn't have to be.

According to such a configuration, it is possible to prevent the steel wall installed inside the bank from interfering with the structure inside the bank and damaging the structure.

According to the present invention, construction cost and construction period can be shortened compared to the conventional art, and collapse of the levee body can be suppressed by sufficiently resisting the water pressure acting on the levee body when the amount of water stored in the valley pond increases.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows the reinforcement structure of the embankment body which concerns on embodiment of this invention, and is shown typically. It is a cross-sectional view of the bank body and the ground in the extension direction center part of a bank body equally. It is a perspective view of a steel sheet pile wall equally. 1 shows an anchor portion, (a) a perspective view showing a first example of the anchor portion, (b) a perspective view showing a second example of the anchor portion, and (c) showing a third example of the anchor portion. It is a perspective view. It is sectional drawing along the extension direction of the steel sheet pile wall installed in the inside of a bank body equally.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram schematically showing the reinforcement structure of the embankment according to the present embodiment, and FIG. 2 is a cross-sectional view of the embankment and the ground at the central portion in the extending direction of the embankment.
In this embodiment, a valley pond 11 is formed by blocking a valley with a bank 10 . The surroundings of the valley pond 11 are surrounded by the natural ground 12 formed by bedrock, hard ground, etc., except for the embankment body 10 .
In FIG. 1, the ground 12 around the valley pond 11 is illustrated in a substantially half elliptical cylinder shape in plan view, but the shape of the ground 12, that is, the shape of the valley pond 11 is not limited to this. Alternatively, the natural ground 12 may be continuous with the slope of the valley.

The bank body 10 is formed in a trapezoidal shape in cross section, and is installed in a straight line in a plan view so as to cross the valley pond 11. It protrudes further outward and is in contact with the natural ground 12. - 特許庁
Further, as shown in FIG. 2 , there is a soft layer 30 immediately below the embankment body 10 , and directly below this soft layer 30 there is a support layer 40 or a bedrock layer. The soft layer 30 and the support layer 40 are also continuous below the valley pond 11 .
In the present embodiment, the embankment body 10 is provided on the upper surface of the soft layer 30 .

If the left side of the crest 10a of the bank body 10 is taken as the upstream side and the right side as the downstream side, a valley pond 11 in which water is stored exists on the upstream side. In addition, the bank body 10 has an upstream slope 10b on the upstream side and a downstream slope 10c on the downstream side across the crest 10a. The inclination angles of the upstream slope 10b and the downstream slope 10c with respect to the ground surface (upper surface of the soft layer 30) are equal, but the inclination angles may be different between the upstream slope 10b and the downstream slope 10c.
Further, as shown in FIG. 1, the upstream slope 10b at the end in the longitudinal direction (extending direction) of the bank body 10 is in contact with the ground 12, and the valley pond 11 is in contact with the upstream slope 10b other than the end. in contact with water.

As shown in FIG. 2, water is always stored in the valley pond 11, and the water surface at the full water level is approximately half or more than the height of the upstream slope 10b of the bank body 10, In addition, the height of the embankment body 10 is set so that the water surface at the design flood level during heavy rain or the like is 1 m or more lower than the crest 10a according to the height of the waves and the water depth.
When the water level is always full, water pressure does not act on the upstream slope 10b above it from the valley pond 11 side, but when the water level always exceeds the full water level, the water pressure increases and acts on the upstream slope 10b. That is, the water pressure acting on the bank body 10 gradually increases when the water surface always exceeds the full water level, and becomes maximum when the water surface reaches the design flood level due to heavy rain or the like.

Moreover, the bank body 10 is provided with a water intake facility (not shown). This water intake facility has a sloping gutter or hard gutter for taking in the water stored in the valley pond 11 and a bottom gutter (see FIG. 5) for conveying the water. Generally, a water intake hole is provided in a sloping pipe buried along the upstream slope 10b of the embankment body 10, and the water taken in from this hole is led to a bottom gutter buried at the bottom of the embankment body 10 to take the water. be done.

Inside the bank body 10, a steel sheet pile wall (steel wall) 15 is installed in a straight line in a plan view along the extending direction (longitudinal direction) of the bank body 10, and the steel sheet pile wall 15 extends Both ends in the direction are located at both ends of the bank body 10 respectively. That is, the steel sheet pile wall 15 is continuously provided from one end of the bank body 10 to the other end.
Furthermore, the steel sheet pile wall 15 is installed in the center in the width direction of the bank 10, its upper end is at the same height as the crown 10a of the bank 10, and is embedded up to the upper surface of the support layer 40. ing. That is, the steel sheet pile wall 15 vertically penetrates the weak layer 30 and the lower end of the steel sheet pile wall 15 is in contact with or close to the upper surface of the support layer 40 . However, the installation position of the steel sheet pile wall 15 in the width direction of the levee body is not limited to the central part, and the steel sheet pile wall 15 is installed near the slope shoulder on the side of the valley pond or near the slope shoulder on the opposite side of the valley pond. may By installing the steel sheet pile wall 15 at a position where the distance from the top end 10a of the bank body 10 to the upper surface of the support layer 40 is the shortest, such as when the upper surface of the support layer 40 is inclined, the upper and lower sides of the steel sheet pile wall 15 The length in the direction can be shortened, making it economical.

The steel sheet pile wall 15 is formed by connecting a plurality of hat-shaped steel sheet piles 16, as shown in FIG.
The steel sheet pile 16 includes a web 16a, flanges 16b formed at both ends of the web 16a, and an arm 16c formed at the end of the flange 16b opposite to the web 16a. A joint 16d is formed in the portion.
Adjacent steel sheet piles 16, 16 are connected by fitting joints 16d, 16d to each other, whereby a steel sheet pile wall 15 is formed.
The steel sheet piles forming the steel sheet pile wall 15 are not limited to hat-shaped steel sheet piles, and may be U-shaped steel sheet piles or straight steel sheet piles.

Further, an anchor portion 20 is installed on the natural ground 12 around the valley pond 11 and in the vicinity of the embankment body 10 , and this anchor portion 20 is connected to the steel sheet pile wall 15 .
The steel sheet pile wall 15 installed inside the bank 10 is formed continuously from one longitudinal end to the other longitudinal end of the bank 10 in plan view. Therefore, the anchor parts 20 are respectively installed on the natural ground 12 near one end of the embankment body 10 and the natural ground 12 near the other end, one anchor part 20 being connected to one end of the steel sheet pile wall 15, and the other anchor part 20 being connected to the other end. is connected to the other end of the steel sheet pile wall 15 .
Further, when connecting the anchor portion 20 to the steel sheet pile wall 15, the tip portion of the anchor portion 20 (the end portion close to the steel sheet pile wall 15 side) is inserted into the embankment body 10 from the upstream slope 10b, and then the tip section to the steel sheet pile wall 15 .
Further, a plurality of anchor portions 20 (two in FIG. 1) may be installed on the natural ground 12 near one end of the embankment body 10 and on the natural ground 12 near the other end.

As a first example of the anchor portion 20, a buttress wall 21 as shown in FIG. 4(a) can be employed.
The buttress wall 21 is formed by connecting a plurality of hat-shaped steel sheet piles 16 in the same manner as the steel sheet pile wall 15 installed inside the bank 10 . Such a buttress 21 extends in a direction intersecting with the steel sheet pile wall 15 . In the present embodiment, the buttress 21 extends straight in a plane view in a direction substantially perpendicular to the steel sheet pile wall 15 . A tip portion (an end portion close to the steel sheet pile wall 15 side) of the buttress wall 21 is connected to the steel sheet pile wall 15 .

On the other hand, the steel sheet pile wall 15 is formed by connecting a plurality of steel sheet piles 16, but the portions that connect the buttresses 21, that is, the steel sheet piles that form both ends of the steel sheet pile wall 15 are made of deformed steel. It is formed by the sheet pile 16A.
This deformed steel sheet pile 16A is obtained by fixing the base end of an arm having a joint at the tip to a hat-shaped steel sheet pile web by welding or the like. The tip of the buttress 21 is connected to the steel sheet pile wall 15 by fitting the joint of the steel sheet pile 16 forming the tip.

When connecting the tip of the buttress 21 to the steel sheet pile wall 15, instead of using the deformed steel sheet pile 16A, a connector (joint ) may be fixed by welding or the like, and the joint of the steel sheet pile 16 forming the tip of the buttress 21 may be engaged with this connector.

As a second example of the anchor portion 20, a support member 22a and a connecting member 22b as shown in FIG. 4B can be employed.
The supporting member 22 a is formed of piles such as steel pipe piles or concrete piles, and is installed in the natural ground 12 around the valley pond 11 and near the bank body 10 . The support members 22a are installed on the ground at both end portions of the steel sheet pile wall 15 so as to be parallel to the steel sheet pile wall 15 and spaced apart from the steel sheet pile wall 15 by a predetermined distance. The upper end of the support member 22a has a height substantially equal to the upper end of the steel sheet pile wall 15. As shown in FIG. However, when the ground strength and ground crest position of the natural ground 12 near one end of the bank body 10 and the natural ground 12 near the other end are different, the support members 22a, 22a at both ends are not necessarily attached to the steel sheet pile wall 15. It is not necessary to arrange them in parallel, and it is not necessary to make the top ends of the support members 22 a and 22 a equal in height to the top end of the steel sheet pile wall 15 .
Also, the connecting member 22b is made of, for example, a tie rod, a PC steel bar, a PC steel wire, or the like having a predetermined tensile strength. Such a connection member 22b is arranged between the support member 22a and the upper end of the steel sheet pile wall 15, the tip of the connection member 22b is connected to the upper end of the steel sheet pile wall 15, and the base end of the support member 22a. connected to the upper end. When the top end position of the support member 22a is different from the upper end of the steel sheet pile wall 15, the connecting member 22b is not horizontal, and rises and falls from the tip end toward the base end. It is set and attached in an oblique direction.

Further, as a third example of the anchor portion 20, a support member 23a and a connecting member 23b as shown in FIG. 4(c) can be employed.
The support member 23 a is formed of, for example, a hat-shaped steel sheet pile, and is installed on the natural ground 12 around the valley pond 11 and near the bank body 10 . The supporting members 23a are placed on both end sides of the steel sheet pile wall 15 at a predetermined distance from the steel sheet pile wall 15, in parallel with the steel sheet pile wall 15, and with the web of the steel sheet pile directed toward the steel sheet pile wall 15 side. is installed in It should be noted that the web surface of the support member 23a may be installed facing the side opposite to the steel sheet pile wall 15. In this case, when the connecting member 23b is pulled toward the steel sheet pile wall 15, the web of the support member 23 and the flange will be separated from each other. Since the steel sheet pile (supporting member 23a) constrains the ground in the space surrounded by , greater ground resistance can be expected. A plurality of supporting members 23a are installed at predetermined intervals in the thickness direction of the supporting members 23a (the direction perpendicular to the steel sheet pile wall 15). Further, the upper end of the support member 23a is approximately equal in height to the upper end of the steel sheet pile wall 15, or the height of the support member 23a is appropriately adjusted according to the top height of the ground.
As with the connecting member 22b, the connecting member 23b has a predetermined tensile strength, such as a tie rod, a PC steel bar, or a PC steel wire. Such a connecting member 23b is arranged between the plurality of supporting members 23a and the upper end of the steel sheet pile wall 15, the tip of the connecting member 23b is connected to the upper end of the steel sheet pile wall 15, and the base end is connected to the plurality of steel sheet pile walls 15. They are connected to the upper ends of the support members 23a.

Although not shown in the drawings, if the natural ground is solid such as a bedrock layer, rock bolts are driven into the natural ground in place of the support members 22a and 23a described above. You may connect by connection members, such as a PC steel bar or a PC steel wire.

Further, as shown in FIG. 5, a structure 25 such as a bottom gutter extending in the width direction perpendicular to the extending direction of the bank 10 (the direction perpendicular to the paper surface in FIG. 5) is provided at the bottom of the bank 10. is provided, part of the lower end of the steel sheet pile wall 15 does not reach the structure 25 . In addition, the water taken in from the water intake hole is led to the slanted sluice pipe buried along the upstream slope 10b of the embankment body 10 and taken into the bottom gutter.
Since the steel sheet pile wall 15 is formed by connecting a plurality of steel sheet piles 16, the lower end portion of the steel sheet pile 16 positioned above the structure 25 among the plurality of steel sheet piles 16 reaches the structure 25. not, that is, a predetermined gap is provided between the lower end of the steel sheet pile 16 and the structure 25 .

As described above, according to the present embodiment, the anchor portion 20 installed in the natural ground 12 around the valley pond 11 and near the bank body 10 is attached to the steel sheet pile wall 15 installed inside the bank body 10. Since they are connected, the embankment body 10 can be reinforced by the steel sheet pile walls 15 and the anchor portions 20 using the strength of the natural ground 12 . Therefore, when the amount of water stored in the valley pond 11 increases, it is possible to sufficiently resist the water pressure acting on the embankment body 10 to prevent the embankment body 10 from collapsing, and the construction cost and construction period can be shortened as compared with the conventional construction.
In addition, the vicinity of the boundary surface (indicated by reference numeral 17 in FIG. 1) between the natural ground 12 and the bank body 10, which is a starting point that causes the bank body collapse, and has different soil properties that are likely to become a water path, is attached to the steel sheet pile wall 15 and the anchor. Since it can be fixed by the part 20, the risk of bank body collapse can be reduced. In order to more strongly reinforce the boundary surface 17 between the natural ground 12 and the embankment body 10, it is more preferable to install the anchor portion 20 on the natural ground 12 near the edge of the embankment body.

Further, when the anchor section 20 includes support members 22a and 23a installed in the natural ground 12 and connection members 22b and 23b that connect the support members 22a and 23a and the steel sheet pile wall 15, the support members The lower end of the steel sheet pile wall 15 is driven into the supporting layer 40 by installing the supporting members 22a and 23a on the natural ground 12 and connecting the supporting members 22a and 23a to the steel sheet pile wall 15 by connecting members 22b and 23b. In addition, the rigidity required for the steel sheet pile wall 15 for resisting an increase in water pressure can be reduced, the material cost of the steel sheet pile wall 15 can be reduced, and an economical reinforcement construction method can be realized.

Furthermore, when the anchor part 20 has a buttress 21 extending in a direction intersecting the steel sheet pile wall 15 and the buttress 21 is connected to the steel sheet pile wall 15, the buttress 21 and the ground 12 The water pressure acting on the bank 10 can also be resisted by the frictional force between the . Therefore, the water pressure acting on the bank body 10 can be sufficiently resisted.
In particular, since the buttress 21 is formed by connecting a plurality of hat-shaped steel sheet piles 16, the uneven shape of the buttress 21 in a plan view absorbs the reaction force from the natural ground 12, Deformation of the sheet pile wall 15 in a direction away from the valley pond 11 can be suppressed.

In addition, the steel sheet pile wall 15 installed inside the bank body 10 has an upper end at a height position equal to the top end 10a of the bank body 10, and is attached to the soft layer 30 below the bank body 10. Since it is embedded up to the upper surface of the support layer 40 below the dam 30, there is a water path that penetrates the bank body 10 from the valley pond 11 side and a water path that penetrates the soft layer 30 directly below the bank body 10 from the valley pond 11 side. can prevent the occurrence of Therefore, seepage failure of the bank body 10 can be suppressed.
Even if an overflow occurs in the bank body 10 during heavy rain, the top end of the steel sheet pile wall 15 is equal to the top end 10a of the bank body 10, so the height of the bank body 10 can be maintained and the bank body 10 is destroyed by overflow. can be suppressed.
In addition, when driving (embedding) the steel sheet pile wall 15 to the support layer 40, a special construction machine such as a crush piler that crushes the ground is required. As a result, it is possible to carry out construction with a normal construction machine, and it is possible to suppress construction costs.

Furthermore, when a structure 25 such as a bottom gutter extending in the width direction of the bank body 10 is provided inside the bank body 10, among the plurality of steel sheet piles 16 constituting the steel sheet pile wall 15, the structure 25 Since the lower end of the steel sheet pile 16 positioned above does not reach the structure 25, the steel sheet pile wall 15 can be prevented from interfering with the structure 25 and damaging the structure 25.

In this embodiment, the steel sheet pile wall 15 installed inside the embankment 10 is embedded up to the upper surface of the support layer 40, but if the resistance strength of the anchor portion 20 against water pressure is insufficient, Part or all of the lower end of wall 15 may be recessed into support layer 40 .
Further, in the present embodiment, the bank body 10 is formed in a straight line in a plan view, but the bank body 10 may bulge slightly in a curved shape in a plan view toward the side of the valley pond or the side opposite to the side of the valley pond. . Even in such a case, the steel sheet pile wall 15 is preferably installed inside the bank 10 so as to extend in a straight line from one end to the other in the extending direction of the bank 10 in plan view. By forming the steel sheet pile wall 15 in a straight line, the total weight of the steel materials constituting the steel sheet pile wall 15 can be reduced and the material cost can be suppressed, compared to when the steel sheet pile wall 15 is driven in a curved shape.
Furthermore, in the present embodiment, the steel sheet pile wall 15 is provided in one row inside the bank body 10, but it may be provided in a plurality of rows. In this case, the steel sheet pile walls 15 adjacent in the width direction of the bank 10 are preferably connected by a plurality of connecting members such as tie rods provided at predetermined intervals in the extending direction of the bank 10 .

10 bank body 10a crest 11 valley pond 12 natural ground 15 steel sheet pile wall (steel wall)
20 anchor part 21 buttress wall 22a, 23a supporting member 22b, 23b connecting member 25 structure 30 soft layer 40 supporting layer

Claims (6)

A bank body reinforcement structure that reinforces the bank body of a valley pond formed by blocking a valley with a bank body,
A steel wall is installed inside the bank body along the extending direction of the bank body,
Anchor portions are installed in the natural ground surrounding the valley pond in contact with both ends in the extending direction of the bank ,
A reinforcement structure for a bank body, wherein the anchor portion is connected to the steel wall to sufficiently resist the water pressure acting on the bank body when the amount of water stored in the valley pond increases. Both ends in the extending direction of the bank protrude laterally from the valley pond in a plan view,
The reinforcement structure of the bank according to claim 1, wherein the steel wall is formed continuously from one longitudinal end to the other longitudinal end of the bank in plan view. 3. The embankment body according to claim 1 , wherein the anchor section includes a support member installed on the ground and a connection member that connects the support member and the steel wall. reinforced structure. 3. The embankment according to claim 1 , wherein the anchor part has a buttress extending in a direction intersecting the steel wall, and the buttress is connected to the steel wall. Reinforcement structure of the body. The steel wall installed inside the embankment has an upper end at the same height as the crest of the embankment and is embedded up to the upper surface of the support layer or bedrock layer positioned below the embankment. The reinforcement structure for the embankment body according to any one of claims 1 to 4 , characterized in that A structure extending in the width direction of the bank is provided inside the bank,
The dam body reinforcement structure according to any one of claims 1 to 5 , wherein a part of the lower end of the steel wall does not reach the structure.

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