Flood prevention structure

Abstract

To prevent water dammed up by a flood-resistant retaining wall from going around to a facility side from the lower part of the flood-resistant retaining wall due to the water pressure difference between the inside and the outside of the facility.SOLUTION: An anti-inundation measure structure 1 preventing inundation to a facility side comprises: a flood-resistant retaining wall 10 installed on the ground and preventing water from flowing into the facility side; and a water shielding wall 20 installed underground and preventing water from going around to the facility side from the lower part of the flood-resistant retaining wall 10. The flood-resistant retaining wall 10 and the water shielding wall 20 are connected.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a flood prevention structure that prevents water from entering a facility. [Background technology]

[0002] One example of such flood prevention structures is a watertight flood-resistant retaining wall (flood-resistant fence) that is constructed to surround almost the entire perimeter of one or more buildings, thereby protecting the building and occupants from flooding in the event of a water disaster such as a flood or high tide, while allowing them to live in evacuation shelter within the building for long periods of time (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6723676 Summary of the Invention [Problem to be solved by the invention]

[0004] The ground on which a flood-resistant retaining wall is constructed is often a mixture of highly permeable ground areas, such as sand layers, and less permeable ground areas, such as clayey soil layers. In such cases, if the flood-resistant retaining wall is simply constructed to surround almost the entire periphery of a building, there is a risk that the water held back by the flood-resistant wall in the highly permeable ground areas will flow around to the facility from below the flood-resistant retaining wall due to the difference in water pressure between inside and outside the facility, causing flooding inside the facility.

[0005] In light of this situation, the main objective of the present invention is to prevent water held back by a flood-resistant retaining wall from flowing around into the facility from below the flood-resistant retaining wall due to the water pressure difference between outside and inside the facility. [Means for solving the problem]

[0006] The first characteristic configuration of the present invention is a flood prevention structure that prevents flooding into a facility, A flood-resistant retaining wall is installed on the ground to prevent water from flowing into the facility, and a water shielding wall is installed underground to prevent water from flowing around the facility from below the flood-resistant retaining wall, The flood-resistant retaining wall and the water-impermeable wall are connected to each other. 、 A water return structure is provided at the joint between the impermeable wall and the flood-resistant retaining wall. It's at the point.

[0007] With this configuration, in the event of a water disaster such as a flood or high tide, the flood-resistant retaining wall can prevent water from flowing into the facility, and the water shielding wall can prevent water held back by the flood-resistant retaining wall from flowing around to the facility from below the flood-resistant retaining wall due to the difference in water pressure between inside and outside the facility. Furthermore, by connecting the flood-resistant retaining wall and the watertight wall, water that is prevented by the watertight wall from flowing around from below the flood-resistant retaining wall to the facility side can be prevented from seeping into the facility side through the gap between the flood-resistant retaining wall and the watertight wall. As a result, in the event of a water disaster such as a flood or high tide, it will be possible to more reliably prevent flood damage from reaching the buildings and people at the facility, enabling evacuees to live safely for a long period of time at the facility. Furthermore, with this configuration, it is possible to more reliably prevent water from entering the facility through the joint between the flood-resistant retaining wall and the water shielding wall, which have different structures, in the event of a flood.

[0010] The present invention Second The characteristic configuration is: A flood prevention structure that prevents flooding into the facility, A flood-resistant retaining wall is installed on the ground to prevent water from flowing into the facility, and a water shielding wall is installed underground to prevent water from flowing around the facility from below the flood-resistant retaining wall, The flood-resistant retaining wall and the water impermeable wall are connected to each other, At the installation location of the flood-resistant retaining wall, a plurality of piles supporting the flood-resistant retaining wall are driven into the ground at a constant pitch in the laying direction of the flood-resistant retaining wall with their heads protruding above ground, The flood-resistant retaining wall is configured with the head side of the pile as a core material, The water impermeable wall is constructed adjacent to the piles at a position closer to the facility than the piles.

[0011] With this configuration, in the event of a water disaster such as a flood or high tide, the flood-resistant retaining wall can prevent water from flowing into the facility, and the water shielding wall can prevent water held back by the flood-resistant retaining wall from flowing around to the facility from below the flood-resistant retaining wall due to the difference in water pressure between inside and outside the facility. Furthermore, by connecting the flood-resistant retaining wall and the watertight wall, water that is prevented by the watertight wall from flowing around from below the flood-resistant retaining wall to the facility side can be prevented from seeping into the facility side through the gap between the flood-resistant retaining wall and the watertight wall. As a result, in the event of a water disaster such as a flood or high tide, it will be possible to more reliably prevent flood damage from reaching the buildings and people at the facility, enabling evacuees to live safely within the facility for a long period of time. Furthermore, with this configuration, it is possible to eliminate the need for large-scale structures such as base slabs to make the flood-resistant retaining wall self-supporting, thereby making it possible to install a flood-resistant retaining wall with high support strength while shortening the construction period, etc. On top of that,For example, when constructing a watertight wall between piles, there is a risk that part of the base reinforcement portion of each pile will be collapsed when the watertight wall is constructed. However, in this configuration, the watertight wall is constructed on the facility side of each pile, eliminating the risk of part of the base reinforcement portion of each pile collapsing. As a result, the watertight wall can be constructed as close to the outermost position of the site as possible without destroying any part of the base of each pile.

[0012] The present invention Third The characteristic configuration is: A flood prevention structure that prevents flooding into the facility, A flood-resistant retaining wall is installed on the ground to prevent water from flowing into the facility, and a water shielding wall is installed underground to prevent water from flowing around the facility from below the flood-resistant retaining wall, The flood-resistant retaining wall and the water impermeable wall are connected to each other, At the installation location of the flood-resistant retaining wall, a plurality of piles supporting the flood-resistant retaining wall are driven into the ground at a constant pitch in the laying direction of the flood-resistant retaining wall with their heads protruding above ground, The flood-resistant retaining wall is configured with the head side of the pile as a core material, The water barrier is constructed between the piles.

[0013] With this configuration, in the event of a water disaster such as a flood or high tide, the flood-resistant retaining wall can prevent water from flowing into the facility, and the water shielding wall can prevent water held back by the flood-resistant retaining wall from flowing around to the facility from below the flood-resistant retaining wall due to the difference in water pressure between inside and outside the facility. Furthermore, by connecting the flood-resistant retaining wall and the watertight wall, water that is prevented by the watertight wall from flowing around from below the flood-resistant retaining wall to the facility side can be prevented from seeping into the facility side through the gap between the flood-resistant retaining wall and the watertight wall. As a result, in the event of a water disaster such as a flood or high tide, it will be possible to more reliably prevent flood damage from reaching the buildings and people at the facility, enabling evacuees to live safely within the facility for a long period of time. Furthermore, with this configuration, it is possible to eliminate the need for large-scale structures such as base slabs to make the flood-resistant retaining wall self-supporting, thereby making it possible to install a flood-resistant retaining wall with high support strength while shortening the construction period, etc. On top of that, According to this configuration, the piles supporting the flood-resistant retaining wall or the base protection sections around the piles also serve as part of the waterproof wall, allowing the waterproof wall to be constructed at the outermost position of the site.

[0016] The present invention Fourth The characteristic configuration is: The flood-resistant retaining wall is constructed of reinforced concrete or steel-reinforced concrete, and the water-resistant wall is constructed of soil cement.

[0017] With this configuration, a flood-resistant retaining wall can be constructed using reinforced concrete or steel-reinforced concrete to have high strength enough to withstand water pressure in the event of a flood, while a water-proof wall that prevents water from flowing around the facility from below the flood-resistant retaining wall can be easily constructed underground using soil cement. [Brief description of the drawings]

[0018] [Figure 1]Plan of flood prevention structure [Diagram 2] Vertical cross section of flood prevention structure [Diagram 3] 1A is a front view of the first flood control structure, FIG. 1B is a vertical cross-sectional view of the first flood control structure, FIG. 1C is a horizontal cross-sectional view of the first flood control structure, and FIG. 1D is a horizontal cross-sectional view showing another embodiment of the first flood control structure. [Figure 4] (a) is a front view of the second flood control structure, (b) is a vertical cross-sectional view of the second flood control structure, and (c) is a horizontal cross-sectional view of the second flood control structure. [Diagram 5] 1A is a partial longitudinal cross-sectional rear view of the third flood control structure, FIG. 1B is a vertical cross-sectional view of the third flood control structure, FIG. 1C is a horizontal cross-sectional view of the third flood control structure, and FIG. 1D is a horizontal cross-sectional view showing another embodiment of the third flood control structure. [Figure 6] Enlarged vertical cross-sectional view of the main part of the first flood control structure showing the water return structure [Figure 7] 1A is an enlarged vertical cross-sectional view of a main part showing a water return structure of a second water ingress prevention structure, and FIG. 1B is an enlarged vertical cross-sectional view of a main part showing another embodiment of the water return structure in the second water ingress prevention structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.

[0020] As shown in Figure 1, the flood prevention structure 1 of the present invention is constructed to surround educational facilities, medical facilities, factories, accommodation facilities, commercial facilities, apartment buildings, etc., consisting of single or multiple buildings 2 constructed on a specified site, thereby preventing flooding into the aforementioned facilities in the event of a water damage such as a flood or high tide, and preventing the water damage from reaching the buildings 2 and people in the facility.

[0021] As shown in Figures 1 and 2, the flood control structure 1 includes a first flood control structure 1A, a second flood control structure 1B, and a pair of third flood control structures 1C, and the flood control structure 1 is constructed by connecting these flood control structures 1A to 1C in a series to surround the aforementioned facilities, etc. Furthermore, the water-inundation control structure 1 is not limited to being constructed as described above, and may be, for example, constructed by connecting the first water-inundation control structure 1A and the third water-inundation control structure 1C, or the second water-inundation control structure 1B and the third water-inundation control structure 1C, as described above, in series as above, or may be constructed by connecting a plurality of water-inundation control structures, including another water-inundation control structure having a different structure in addition to the first water-inundation control structure 1A, the second water-inundation control structure 1B, and the third water-inundation control structure 1C, in series as described above.

[0022] As shown in Figures 1 to 7, flood control structure 1 is equipped with flood-resistant retaining wall 10 installed above ground to prevent water from flowing into a facility, and water impermeable wall 20 installed underground to prevent water from flowing around the facility from below flood-resistant retaining wall 10. Flood-resistant retaining wall 10 has a predetermined height and is installed above ground so as to surround the facility. Water impermeable wall 20 has a predetermined embedded length and is installed underground so as to surround the facility. In this embodiment, the water shielding wall 20 is exemplified as having a long embedded length that reaches a less permeable ground portion 3B, such as a clayey soil layer, below a more permeable ground portion 3A, such as a sand layer, in the ground 3. However, the present invention is not limited to this. For example, as long as it is possible to prevent water from flowing around from below the flood-resistant retaining wall 10 toward the facility side, the water shielding wall 20 may have a short embedded length that does not reach the less permeable ground portion 3B.

[0023] The flood-resistant retaining wall 10 includes a first flood-resistant retaining wall 11 (see Figs. 1-4, 6-7) made of SRC (steel-reinforced concrete) used in the first flood-resistant structure 1A and the second flood-resistant structure 1B, and a second flood-resistant retaining wall 12 (see Figs. 1, 5) made of RC (reinforced concrete) used as a flood gate wall in the third flood-resistant structure 1C. The impermeable walls 20 include a first impermeable wall 21 (see Figs. 2-3, 6) used in the first flood-resistant structure 1A, a second impermeable wall 22 (see Figs. 2, 4, 7) used in the second flood-resistant structure 1B, and a third impermeable wall 23 (see Fig. 5) used in the third flood-resistant structure 1C. The first impermeable wall 21 and the third impermeable wall 23 are buried at a position closer to the facility than the first flood-resistant retaining wall 11. The second impermeable wall 22 is buried directly below the first flood-resistant retaining wall 11.

[0024] As shown in Figs. 2 to 4 and 6, at the installation location of each first flood-resistant retaining wall 11, H-shaped steel piles 13A as a plurality of piles 13 supporting the first flood-resistant retaining wall 11 are driven into the ground at a constant pitch in the laying direction of the first flood-resistant retaining wall 11 with their heads 13a protruding above ground. A foot fixing portion 14 is formed around each H-shaped steel pile 13A, which fixes each H-shaped steel pile 13A to the ground 3 by solidifying a foot fixing liquid (cement milk) injected around the piles. As shown in Fig. 5, at the installation location of each second flood-resistant retaining wall 12, first RC piles 13B as a plurality of piles 13 supporting the second flood-resistant retaining wall 12 and supporting the reaction force of the second flood-resistant retaining wall (floodgate wall) 12 and the waterproof door 4 in the event of a flood are driven into the ground in pairs in the inward and outward directions of the facility at a constant pitch in the laying direction of each second flood-resistant retaining wall 12. Each of the first RC piles 13B has a head 13b connected to a foundation portion 15 and a column portion 16 of RC construction.

[0025] As shown in Figs. 2-4 and 6-7, each first flood-resistant retaining wall 11 is constructed across a plurality of H-shaped steel piles 13A, with the heads 13a of the H-shaped steel piles 13A as the core material. The lower end of each first flood-resistant retaining wall 11 is buried in the ground. As shown in Fig. 5, each second flood-resistant retaining wall 12 is constructed across a plurality of first RC piles 13B, connected to the heads 13b of a given first RC pile 13B via a foundation 15 and a column 16. As shown in Figs. 1 and 5, each second flood-resistant retaining wall 12 includes a floor slab 12A connected to the foundation 15 with its upper surface exposed to the ground surface, and a retaining wall portion 12B constructed between adjacent given column portions 16. An entrance 12C is formed between a pair of column portions 16 where the retaining wall portion 12B is not constructed, and a waterproof door 4 is provided for opening and closing the entrance 12C. Below the deck 12A, a number of second RC piles 17 are driven into the ground at a regular pitch in the direction in which the rails (not shown) are laid (the direction in which the second flood-resistant retaining wall 12 is laid) to prevent the rails (not shown) laid on the upper surface of the deck 12A from sinking to guide the opening and closing of the waterproof door 4.

[0026] As shown in Figs. 2-3 and 6, each first impermeable wall 21 is constructed adjacent to each H-shaped steel pile 13A supporting the first flood-resistant retaining wall 11 at a position closer to the facility than the H-shaped steel pile 13A. As shown in Fig. 3(a)-(c), each first impermeable wall 21 is made of a soil cement wall (solidified wall) 21A formed to a uniform thickness by improving the intermediate layer ground, and the upper end portion thereof is connected to the lower end portion of the first flood-resistant retaining wall 11 via a water return structure 30. Each water return structure 30 is constructed of a concrete plate 31 connected to the lower end portion of the first flood-resistant retaining wall 11 via a slip stopper bar 5 (see Fig. 6) or an adhesive anchor (not shown). The first flood-resistant retaining wall 11, the first impermeable wall 21, and the water return structure 30 constitute the first flood-control structure 1A described above. Furthermore, the first watertight wall 21 is not limited to being made of a soil cement wall 21A of equal thickness, but may be constructed, for example, by connecting a plurality of soil cement piles (solidification piles) 21B formed by columnar improvement in an overlapping state, as shown in (d) of Figure 3.

[0027] As shown in Fig. 2, Fig. 4, and Fig. 7, each second impermeable wall 22 is constructed between adjacent H-shaped steel piles 13A in the laying direction of the first flood-resistant retaining wall 11. Specifically, the second impermeable wall 22 is constructed by connecting a plurality of soil cement piles (solidified piles) 22A formed by columnar improvement between adjacent H-shaped steel piles 13A in the laying direction of the first flood-resistant retaining wall 11 in an overlapping state, directly below the first flood-resistant retaining wall 11. The base fixing portion 14 of each H-shaped steel pile 13A has a recess 14a formed therein for overlapping adjacent soil cement piles 22A in the connecting direction. As shown in Fig. 7(a), a water return structure 30 is provided at the connecting portion between the first flood-resistant retaining wall 11 and the second impermeable wall 22, which is composed of a step portion 32 in which the outside of the facility is lower than the side of the facility. The first flood-resistant retaining wall 11, the second water impermeable wall 22, and the water return structure 30 constitute the second flood control structure 1B described above. Furthermore, the water return structure 30 is not limited to being configured with the step portion 32 described above, but may be configured, for example, with an inclined portion 33 in which the outside of the facility is lower than the facility side, as shown in (b) of Figure 7.

[0028] As shown in (a) to (c) of FIG. 5, each of the third impermeable walls 23 is constructed between the second RC piles 17 adjacent to each other in the laying direction of the second flood-resistant retaining wall 12. Specifically, the third impermeable walls 23 are constructed at a position closer to the facility than each of the first RC piles 13B supporting the second flood-resistant retaining wall 12 by connecting a plurality of soil cement piles (solidified piles) 23A formed by columnar improvement in an overlapping state between the second RC piles 17 adjacent to each other in the laying direction of the second flood-resistant retaining wall 12. Each of the second RC piles 17 has a recess 17a formed therein to allow the adjacent soil cement piles 23A to overlap in the connecting direction. The third flood-resistant structure 1C described above is constructed from the second flood-resistant retaining wall 12 and the third impermeable wall 23. Furthermore, the third water-resistant wall 23 is not limited to being constructed by connecting a plurality of soil cement piles 23A between the second RC piles 17 as described above, but may also be composed of a soil cement wall (solidified wall) 23B of equal thickness constructed at a position closer to the facility than each of the first RC piles 13B, for example, as shown in (d) of Figure 5, which is formed by improving the mid-layer ground.

[0029] As described above, the flood control structure 1 exemplified in this embodiment is provided with the flood-resistant retaining wall 10 that is installed above ground to prevent water from flowing into the facility, and the impermeable wall 20 that is installed underground to prevent water from flowing around to the facility from below the flood-resistant retaining wall 10, and the flood-resistant retaining wall 10 and the impermeable wall 20 are connected to each other. A water return structure 30 is provided at the connection point between the impermeable wall 20 and the flood-resistant retaining wall 10. As a result, in the event of a water disaster such as a flood or high tide, the flood-resistant retaining wall 10 can prevent water from flowing into the facility, and the water shielding wall 20 can prevent water held back by the flood-resistant retaining wall 10 from flowing around to the facility from below the flood-resistant retaining wall 10 due to the difference in water pressure between inside and outside the facility. Furthermore, since the flood-resistant retaining wall 10 and the waterproof wall 20 are connected and a water-return structure 30 is provided at the connection point, it is possible to more reliably prevent the water that is prevented by the waterproof wall 20 from flowing around from below the flood-resistant retaining wall 10 to the facility side from seeping into the facility side through the gap between the flood-resistant retaining wall 10 and the waterproof wall 20. As a result, in the event of a water disaster such as a flood or high tide, it is possible to more reliably prevent the water damage from reaching the buildings 2 and people in the facility, making it possible for evacuees to live safely for a long period of time within the facility.

[0030] In the flood control structure 1 illustrated in this embodiment, each of the flood-resistant retaining walls 11, 12 is supported by a plurality of H-shaped steel piles 13A or first RC piles 13B driven into the ground at a constant pitch in the laying direction of the walls. This allows each of the flood-resistant retaining walls 11, 12 to be installed with high support strength. In particular, the H-shaped steel piles 13A supporting the first flood-resistant retaining wall 11 are driven into the ground at a constant pitch in the laying direction of each first flood-resistant retaining wall 11 with their heads 13a protruding above ground, and each first flood-resistant retaining wall 11 is constructed using the heads 13a of the H-shaped steel piles 13A as the core material. This makes it possible to eliminate the need for large-scale structures such as base slabs to make each first flood-resistant retaining wall 11 self-supporting. As a result, it is possible to install a flood-resistant retaining wall 10 with high support strength while shortening the construction period.

[0031] Furthermore, in the flood control structure 1 exemplified in this embodiment, each first impermeable wall 21 is constructed adjacent to each H steel pile 13A at a position closer to the facility than each H steel pile 13A. Also, each second impermeable wall 22 is constructed between adjacent H steel piles 13A in the laying direction of the first flood-resistant retaining wall 11, and each third impermeable wall 23 is constructed between adjacent second RC piles 17 in the laying direction of the second flood-resistant retaining wall 12, etc. As a result, each first impermeable wall 21 can be constructed as close as possible to the outermost position of the site, without destroying a part of the foot protection portion 14 formed around each H-shaped steel pile 13A. Also, each second impermeable wall 22 can be constructed as close as possible to the outermost position of the site, while using the foot protection portion 14 formed around each H-shaped steel pile 13A as part of the second impermeable wall 22, and each third impermeable wall 23 can be constructed as close as possible to the outermost position of the site, while using each second RC pile 17 as part of the third impermeable wall 23.

[0032] In the flood control structure 1 illustrated in this embodiment, each first flood-resistant retaining wall 11 is constructed of steel reinforced concrete, each second flood-resistant retaining wall 12 is constructed of reinforced concrete, and each water-resistant wall 21-23 is constructed of soil cement. This allows each flood-resistant retaining wall 11, 12 to be constructed using steel-reinforced concrete or reinforced concrete so as to have high strength capable of withstanding water pressure in the event of a flood, while each water-resistant wall 21-23 which prevents water from flowing around the facility from below each flood-resistant retaining wall 11, 12 can be easily constructed underground using soil cement.

[0033] [Another embodiment] Another embodiment of the present invention will now be described. The configurations of the respective alternative embodiments described below are not limited to being applied alone, but may also be applied in combination with the above-described embodiment or other alternative embodiments.

[0034] (1) In the above embodiment, the water-flooding control structure 1 is exemplified as a structure in which a first water-flooding control structure 1A and a second water-flooding control structure 1B are connected via a third water-flooding control structure 1C. However, this is not limited to this, and for example, the first water-flooding control structure 1A and the second water-flooding control structure 1B may be directly connected without the third water-flooding control structure 1C.

[0035] (2) In the above embodiment, each first flood-resistant retaining wall 11 is exemplified as being made of SRC (steel reinforced concrete) construction supported by a plurality of H-shaped steel piles 13A with the heads 13a of the piles as the core material. However, the present invention is not limited to this and may be made of RC (reinforced concrete) construction supported by a plurality of RC piles, for example.

[0036] (3) In the above embodiment, each second flood-resistant retaining wall 12 is exemplified as being made of RC (reinforced concrete) construction supported by a plurality of first RC piles 13B. However, the present invention is not limited to this and may be made of SRC (steel reinforced concrete) construction supported by a plurality of H-shaped steel piles 13A with the heads 13a of the piles as the core material.

[0037] (4) In the above embodiment, each third watertight wall 23 is illustrated as being constructed at a position closer to the facility than each first RC pile 13B, but this is not limited thereto and, for example, the third watertight wall 23 may be constructed between adjacent first RC piles 13B in the laying direction of the second flood-resistant retaining wall 12.

[0038] (5) In the above embodiment and other embodiments (2) and (3), H-shaped steel piles 13A or RC piles 13B are exemplified as piles 13 supporting each flood-resistant retaining wall 10 (first flood-resistant retaining wall 11 and second flood-resistant retaining wall 12). However, this is not limited to the above, and the type of piles 13 used can be changed in various ways depending on the thickness of each flood-resistant retaining wall 10 and the site conditions (such as soil quality and surrounding conditions). For example, PHC piles may be used depending on the site conditions. [Explanation of symbols]

[0039] 1. Flood prevention structure 10 Flood-resistant retaining walls 13 stake 13a head 20 Water-impermeable walls 30 Water return structure

Claims

1. A flood prevention structure that prevents flooding into a facility, A flood-resistant retaining wall is installed on the ground to prevent water from flowing into the facility, and a water shielding wall is installed underground to prevent water from flowing around the facility from below the flood-resistant retaining wall, The flood-resistant retaining wall and the water impermeable wall are connected to each other, A flood prevention structure in which a water return structure is provided at the connection point between the water shielding wall and the flood-resistant retaining wall.

2. A flood prevention structure for preventing flooding into a facility, A flood-resistant retaining wall is installed on the ground to prevent water from flowing into the facility, and a water shielding wall is installed underground to prevent water from flowing around the facility from below the flood-resistant retaining wall, The flood-resistant retaining wall and the water impermeable wall are connected to each other, At the installation location of the flood-resistant retaining wall, a plurality of piles supporting the flood-resistant retaining wall are driven into the ground at a constant pitch in the laying direction of the flood-resistant retaining wall with their heads protruding above ground, The flood-resistant retaining wall is configured with the head side of the pile as a core material, A flood prevention structure in which the water barrier wall is constructed adjacent to the piles at a position closer to the facility than the piles.

3. A flood prevention structure for preventing flooding into a facility, A flood-resistant retaining wall is installed on the ground to prevent water from flowing into the facility, and a water shielding wall is installed underground to prevent water from flowing around the facility from below the flood-resistant retaining wall, The flood-resistant retaining wall and the water impermeable wall are connected to each other, At the installation location of the flood-resistant retaining wall, a plurality of piles supporting the flood-resistant retaining wall are driven into the ground at a constant pitch in the laying direction of the flood-resistant retaining wall with their heads protruding above ground, The flood-resistant retaining wall is configured with the head side of the pile as a core material, A flood prevention structure in which the water barrier wall is constructed between the piles.

4. 4. A flood prevention structure according to claim 1, wherein the flood-resistant retaining wall is constructed of reinforced concrete or steel-reinforced concrete, and the water-resistant wall is constructed of soil cement.

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