Rainwater storage tank using multi-unit precast box culverts

Abstract

Instead of forming notches in the precast box culvert itself, the precast box culverts are arranged in a multi-unit configuration so that the intermediate column members are not adjacent to each other, thereby ensuring water flow within the rainwater storage tank and providing a rainwater storage tank with high rigidity. [Solution] A rainwater storage tank is constructed by arranging multiple precast box culverts in a series in a water storage area, wherein the precast box culverts are arranged in a series such that the intermediate column members supporting the top plate covering the water storage space are not adjacent to each other in the longitudinal direction.

Description

Technical Field

[0001] The present invention relates to a rainwater storage tank constructed by arranging precast box culverts in a multi - row manner in a water storage area.

Background Art

[0002] In recent years in our country, heavy rain records exceeding 100 mm / hr have been observed, and great damage has occurred due to locally occurring heavy rain. This is due to, in addition to abnormal weather, the decline in water retention and water infiltration functions due to the asphaltification of urban areas, the existence of many small and medium - sized rivers with small catchment areas, and the insufficient flow - down capacity of existing sewer facilities. Therefore, rainwater storage facilities have been installed for the purpose of suppressing the outflow of rainwater and protecting urban life in the river basin. Precast concrete box culverts may be used for rainwater storage tanks, and this box culvert is constructed by arranging a plurality of them in a multi - row manner.

[0003] For example, Patent Document 1 discloses a swimming pool device. The device includes a plurality of column block row groups in which a plurality of column blocks having a substrate portion, a column portion formed upward on this substrate portion, and a top - plate receiving portion formed on the upper part of this column portion are arranged in parallel, and a plurality of top plates whose both ends are placed between the top - plate receiving portions of each column block of adjacent column block row groups. The upper part of the column block of the column block row group forms a beam receiving portion facing an adjacent column block, and both ends of a beam block formed with a top - plate receiving portion between the beam receiving portions of adjacent column blocks of this column block row group are placed, and both ends of the top plate are placed between the top - plate receiving portions of the beam blocks of the adjacent column block row groups. According to this, it can be cleaned using a large - scale cleaning machine, and the efficiency of the cleaning work can be improved.

[0004] Although this device is constructed using a multi-section box culvert, its cross-sectional shape is based on columnar blocks (intermediate members) with L-shaped end members and water passage holes (openings), and the beam block located at the top slab is joined to the L-shaped end members and columnar blocks by pin connections. Therefore, although it has a box shape, it differs from a box culvert structure in that the joints are rigidly connected.

[0005] Furthermore, Patent Document 2 discloses a precast concrete structure and a storage tank equipped with the precast concrete structure. The storage tank has a structure in which a portal frame is continuously formed in the left-right direction, comprising a pair of side walls spaced apart from each other, one or more intermediate walls erected between the side walls, and slabs erected between each side wall or intermediate wall. In this concrete structure made of precast concrete, multiple such continuous portal frames are densely arranged in the front-rear direction. The slabs are provided with loop reinforcement that projects in an arch shape across the vertical direction on both their left and right end faces, and the intermediate walls are provided with loop reinforcement that projects in an arch shape across the left-right direction on their upper surfaces. The upper part of the intermediate wall is formed by arranging three loop reinforcements—the loop reinforcements of the slab protruding from the left and right directions, and the loop reinforcement of the intermediate wall protruding from below—in a twisted position while overlapping in the front-rear direction to form a loop reinforcement tunnel. Multiple reinforcing bars are arranged on the inner circumference along the extension direction of the loop reinforcement tunnel, and concrete is poured to enclose the loop reinforcement tunnel. Thus, a precast concrete structure in which the intermediate wall and the slab are firmly integrated can be provided, while construction is relatively easy.

[0006] This storage tank is a box culvert structure with a loop-shaped joint construction method, but the intermediate wall members are provided with drainage holes for rainwater inflow. When designing the seismic resistance of a multi-section box culvert, extremely large moments act on the intermediate walls. Therefore, while ensuring sectional rigidity, and considering economic factors such as the complexity of formwork construction and rebar processing, it is desirable to avoid providing drainage holes in the intermediate wall. However, it has become customary to provide drainage holes in the intermediate wall of conventional precast rainwater storage tanks.

[0007] In contrast, Patent Document 3 describes a method of arranging blocks having upright side walls, or sets of multiple such blocks arranged in the front-to-back direction, in parallel with alternating offsets in the front-to-back direction, and the block A flood control device is disclosed, characterized in that a bottom plate is provided between the bottoms of the rocks, and a cover plate is bridged between the upper parts of the blocks. In this device, blocks or sets of blocks are arranged in parallel with alternating front-to-back offsets, so that the side walls between blocks or sets of blocks are spaced apart. This allows for an oblique view of the retention pond, improving visibility and facilitating maintenance of the device. Furthermore, heavy machinery for removing mud can move freely between the side walls not only vertically and horizontally but also diagonally, making cleaning easier.

[0008] Thus, the apparatus of Patent Document 3 facilitates maintenance and management of the apparatus by arranging blocks or sets of blocks in parallel with alternating front-to-back offsets, rather than forming notches in the precast box culvert itself, as is done with the storage tank of Patent Document 2. However, simply spacing out the side walls between blocks or sets of blocks is not sufficient to improve water permeability. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 11-081429 [Patent Document 2] Japanese Patent Publication No. 2017-053169 [Patent Document 3] Japanese Patent Application Publication No. 6-272290 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Therefore, in order to solve the problems of the conventional invention, the present invention aims to provide a rainwater storage tank with high rigidity by ensuring water flow within the rainwater storage tank, not by forming notches in the precast box culvert itself, but by arranging and installing multiple precast box culverts in a connected manner, and further by forming depressions or grooves on the top surface of the bottom plate of the installed precast box culvert. [Means for solving the problem]

[0011] To address the problems of the prior art, the present invention employs the following technical solutions.

[0012] The present invention relates to, A rainwater storage tank constructed by arranging multiple precast box culverts in a series in the direction of the opening within the water storage area is, Precast box culverts A row A consisting of wall members surrounding the water storage space, a top plate covering the water storage space enclosed by the wall members, A intermediate column members supporting the top plate, and A base plate positioned between the A intermediate column members, A row B consisting of a wall member enclosing the water storage space, a top plate covering the water storage space enclosed by the wall member, a B intermediate column member supporting the top plate and positioned not adjacent to the A intermediate column member, and a B base plate positioned between the B intermediate column members, It is composed of, Precast box culverts in rows A and B are arranged alternately in multiple units in the direction of their opening. A recess is formed in the top surface of base plate A and base plate B, along the direction of the box culvert's opening. It is characterized by the following:

[0013] Furthermore, the present invention relates to, A rainwater storage tank constructed by arranging multiple precast box culverts in a series in the direction of the opening within the water storage area is, The precast box culvert is composed of a wall member surrounding the water storage space, a top plate covering the water storage space surrounded by the wall member, an A intermediate column member supporting the top plate, and an A bottom plate arranged between the A intermediate column members, forming an A row, a wall member surrounding the water storage space, a top plate covering the water storage space surrounded by the wall member, a B intermediate column member supporting the top plate and arranged at a position not adjacent to the A intermediate column member, and a B bottom plate arranged between the B intermediate column members, forming a B row, and is composed of The precast box culverts of the A row and the B row are arranged in a multi - connected manner alternately in their opening directions, grooves are formed diagonally on the top surface parts of the A bottom plate and the B bottom plate, and the grooves are continuous along the opening directions of the box culverts of the A row and the B row arranged in a multi - connected manner alternately. It is characterized by this.

[0014] Furthermore, for the rainwater storage tank constructed by arranging precast box culverts in a multi - connected manner in the opening direction in the water storage area according to the present invention, the precast box culvert is composed of a wall member surrounding the water storage space, a top plate covering the water storage space surrounded by the wall member, an A intermediate column member supporting the top plate, and an A bottom plate arranged between the A intermediate column members, forming an A row, a wall member surrounding the water storage space, a top plate covering the water storage space surrounded by the wall member, a B intermediate column member supporting the top plate and arranged at a position not adjacent to the A intermediate column member, and a B bottom plate arranged between the B intermediate column members, forming a B row, [[ID=?]]and is composed of The precast box culverts of the A row and the B row are arranged in a multi - connected manner alternately in their opening directions, groove I is formed along the opening direction of the box culvert on the edge part of the A bottom plate and the B bottom plate abutting against the A intermediate column member or the B intermediate column member, and the groove I is continuous along the opening directions of the box culverts of the A row and the B row arranged in a multi - connected manner alternately. It is characterized by the following: [Effects of the Invention]

[0015] (1) Since the precast box culvert itself does not have water passages, it can store rainwater in the storage tank while maintaining high rigidity. (2) The structure can be made of reinforced concrete, prestressed concrete, or prestressed reinforced concrete, and the joints of each member can be constructed with rigid connections. Therefore, compared to conventional precast rainwater storage tanks, it is possible to extend the span and provide a storage tank with excellent void ratio (storage capacity). (3) Not only can the structures be arranged in a straight line, but by changing the combination of arrangements of the structures, they can be installed even if the installation site has an oblique or polygonal shape. (4) According to the "Technical Manual for Precast Underground Rainwater Storage Facilities (Wall-Type Multi-Unit) / Japan Sewerage New Technology Organization," conventional precast rainwater storage tanks are for open spaces (soil cover 0-1.5m, superimposed load 10kN / m 2 Since it is intended for use in the following locations, it cannot accommodate embankments exceeding 1.5m or T-loads. However, because the rainwater storage tank according to the present invention is based on a box culvert, it can accommodate design conditions that take into account high embankments and T-loads, as well as design conditions that take into account open spaces. (5) By forming depressions or grooves on the top surface of the bottom slab of precast box culverts that are arranged in a multi-unit configuration, high water permeability can be obtained within the storage tank. [Brief explanation of the drawing]

[0016] [Figure 1] An upper perspective view showing one embodiment of a rainwater storage tank in which precast box culverts are arranged in a multi-unit configuration in the direction of their opening. [Figure 2] A side view of the rainwater storage tank shown in Figure 1, seen from its opening side. [Figure 3]The images show a schematic top view of the rainwater storage tank illustrating the flow of stored water (upper left), a side view from the wall member side (upper right), and side views of two types of precast box culverts, A and B, from their opening side (bottom). [Figure 4] An overhead perspective view of the rainwater storage tank shown in Figure 1, with some components removed to make the connecting parts more visible. [Figure 5] An upward perspective view showing the connection structure between top plates in one embodiment of the connection structure between intermediate column members and base plates. [Figure 6] A side view of two precast box culverts (row A and row B) with different structures, seen from the opening side. [Figure 7] Side view of two types of precast box culverts, A and B, with different structures, as seen from the opening side, showing each A and B culvert individually and with A and B connected together. [Figure 8] An upper perspective view (right) and a partially enlarged view (left) of a rainwater storage tank showing one embodiment in which a groove I is formed in the bottom slab. [Figure 9] A top view (upper figure) and a side view (lower figure) of a rainwater storage tank showing an embodiment in which a groove I is formed in the bottom plate. [Figure 10] Top view of a rainwater storage tank showing one embodiment in which a groove X is formed in the bottom plate. [Figure 11] Top view of a rainwater storage tank showing one embodiment in which a groove X is formed in the bottom plate. [Figure 12] Top view of a rainwater storage tank showing one embodiment in which a groove X is formed in the bottom plate. [Figure 13] Top view of a rainwater storage tank showing one embodiment in which grooves I and X are formed in the bottom plate. [Figure 14] The image shows a top view (upper left) of a rainwater storage tank, an example of an arrangement of precast box culverts, a side view (upper right) seen from the wall member side, and side views (lower) of two types of precast box culverts, A and B, seen from their opening side. [Figure 15]The images show an example of a precast box culvert arrangement: a top view of a rainwater storage tank (upper left), a side view from the wall member side (upper right), and side views of two types of precast box culverts, A and B, from their openings (center), and a cross-sectional view (bottom). [Figure 16] The images show an example of a precast box culvert arrangement: a top view of a rainwater storage tank (upper left), a side view from the wall member side (upper right), and side views of two types of precast box culverts, A and B, from their openings (center), and a cross-sectional view (bottom). [Figure 17] Top view of a rainwater storage tank showing an example of a precast box culvert arrangement. [Figure 18] Top view of a rainwater storage tank showing an example of a precast box culvert arrangement. [Figure 19] Top view of a rainwater storage tank showing an example of a precast box culvert arrangement. [Figure 20] The images show a top view (upper left) of a rainwater storage tank, an example of a precast box culvert arrangement, a side view (upper right) seen from the wall member side, and side views (lower) of two types of precast box culverts, A and B, seen from their opening sides. [Figure 21] Upper perspective view of the rainwater storage tank in the embodiment shown in Figure 20. [Modes for carrying out the invention]

[0017] Specific embodiments of the present invention will be described in detail with reference to the drawings.

[0018] <Example 1> The rainwater storage tank according to the present invention is constructed by arranging multiple precast box culverts in the opening direction within the water storage area. The precast box culvert is composed of two columns: a column A consisting of a wall member surrounding the water storage space, a top plate covering the water storage space surrounded by the wall member, an intermediate column A supporting the top plate, and a bottom plate A positioned between the intermediate column A members; and a column B consisting of a wall member surrounding the water storage space, a top plate covering the water storage space surrounded by the wall member, an intermediate column B supporting the top plate and positioned not adjacent to the intermediate column A members, and a bottom plate B positioned between the intermediate column B members. Figure 1 is a top perspective view showing one embodiment of this rainwater storage tank. Figure 2 is a side view of the rainwater storage tank shown in Figure 1, viewed from its opening side. The box culvert closest to the viewer is represented by a solid line, while the intermediate column member 2 of the box culvert visible behind it is represented by a dotted line. Thus, in the present invention, the precast box culvert arranged as a rainwater storage tank has a structure in which rows A and B are arranged in a multi-unit configuration, so that the intermediate column members 2 that support the top plate 1 covering the water storage space are not adjacent to each other.

[0019] Furthermore, recesses are formed on the top surfaces of the A-bottom plate of the A-row precast box culverts and the B-bottom plate of the B-row precast box culverts, along the direction of the box culvert's opening. As a result, a flow is generated in the stored water, as shown in Figure 3.

[0020] <Example 2> Figure 4 is an overhead perspective view of the rainwater storage tank shown in Figure 1, with some components removed to make the connecting parts more visible. Figure 5 is an overhead perspective view that clearly shows the connection structure between the top plates in one embodiment of the connection structure between the intermediate column member and the base plate. As shown in Figures 4 and 5, in the precast box culvert of the rainwater storage tank, the base plate 3 of row B is placed between two intermediate column members 2 of row A and another intermediate column member 2 of row A. This allows precast box culverts to be arranged in a multi-unit configuration so that the intermediate column members 2 supporting the top slab 1 covering the water storage space are not adjacent to each other. Alternatively, instead of the base slab 3, cast-in-place concrete can be used.

[0021] <Example 3> Figure 6 shows side views of two types of precast box culverts (rows A and B) with different structures, arranged in a multi-unit configuration, as seen from the opening side. Each row of precast box culverts consists of a wall member 4 enclosing a water storage space, a top plate 1 covering the water storage space enclosed by the wall member 4, intermediate column members 2 supporting the top plate 1, and a base plate 3 positioned between the intermediate column members 2 in a direction perpendicular to the longitudinal direction of the intermediate column members 2. Furthermore, the precast box culverts in column A and column B differ in the position of the intermediate column members 2 that support the top slab 1 covering the water storage space. Therefore, when the precast box culverts in column A and column B are arranged in a multi-unit configuration in the direction of their openings, the intermediate column members 2 in column A and column B will not be adjacent to each other.

[0022] <Example 4> Figure 7 is a side view of two types of precast box culverts, A and B, which have different structures, as seen from their opening side. The precast box culvert in column A consists of a wall member 4a that encloses the water storage space, a top plate 1a that covers the water storage space enclosed by the wall member 4a, an intermediate column member 2a that supports the top plate 1a, and a bottom plate 3a that is positioned between the intermediate column members 2a. The precast box culvert in column B consists of a wall member 4b that encloses the water storage space, a top plate 1b that covers the water storage space enclosed by the wall member 4b, a B intermediate column member 2b that supports the top plate 1b and is positioned not adjacent to the A intermediate column member 2a, and a B bottom plate 3b that is positioned between the B intermediate column members 2b. These two types of precast box culverts, A and B, with different structures, are arranged in a multi-unit configuration in the direction of their opening, so that the intermediate column members 2a of A and 2b of B are not adjacent to each other.

[0023] <Example 5> Figure 8 is an overhead perspective view of a rainwater storage tank showing one embodiment in which a groove I is formed in the bottom slab. A groove I is formed along the opening direction of the box culvert at the edge portion of the base plate A and the base plate B that abuts against the intermediate column member A or the intermediate column member B. This groove I is formed continuously along the opening direction of the box culverts in rows A and B, which are arranged alternately in a multi-series configuration. Furthermore, the top surfaces of base plates A and B can be shaped to slope downwards towards groove I. This makes it easier for water stored on the top surfaces of base plates A and B to flow into groove I.

[0024] <Example 6> Figure 9 shows a top view and a side view from the opening side of a rainwater storage tank, illustrating one embodiment in which a groove I is formed in the bottom slab. The grooves I are formed continuously along the opening direction of the box culverts in rows A and B, which are arranged alternately in a multi-series manner, thereby improving water permeability within the rainwater storage tank.

[0025] <Example 7> Figures 10 to 12 are top views of a rainwater storage tank showing one embodiment in which a groove X is formed in the bottom plate. Grooves X are formed diagonally on the top surfaces of base plates A and B. Groove X can be formed on either one of the diagonals of the top surfaces of bottom plate A and bottom plate B, as shown in Figure 10 or Figure 11, or it can be formed on both diagonals, as shown in Figure 12. In either case, the groove X is formed continuously along the opening direction of the box culverts in rows A and B, which are arranged alternately in a multi-series configuration. This improves the water permeability within the rainwater storage tank.

[0026] <Example 8> Figure 13 is a top view of a rainwater storage tank showing one embodiment in which both groove I and groove X are formed in the bottom plate A and the bottom plate B. A groove I is formed along the opening direction of the box culvert on the edge portion of the A base plate and the B base plate that abuts against the A intermediate column member or the B intermediate column member, and a groove X is formed diagonally on the top portion of the A base plate and the B base plate, thereby improving the water permeability within the rainwater storage tank. Furthermore, the groove X formed together with groove I can also be formed on either one of the diagonals of the top surfaces of the A base plate and the B base plate, as shown in Figure 10 or Figure 11.

[0027] <Example 9> As shown in Figures 4 and 5, the precast box culverts of Examples 1 to 8 can be rigidly connected in a state where the A intermediate column member 2a of row A and the B base plate 3b of row B are adjacent to each other, and the B intermediate column member 2b of row B and the A base plate 3a of row A are adjacent to each other. This rigid connection can be made using PC steel bars or connecting fittings. Because the joints of each component are constructed with rigid connections, it is possible to create longer spans compared to conventional precast rainwater storage tanks, and a storage tank with superior void ratio (storage capacity) can be provided. Furthermore, the base slabs of the intermediate column members (2a, 2b) in rows A and B can be connected to the opening direction of the multi-unit precast box culverts via the base slab members.

[0028] <Other examples> The rainwater storage tanks according to Examples 1 to 9 can be constructed by arranging multiple precast box culverts in the configuration shown in Figures 14 to 19.

[0029] Furthermore, as shown in Figures 20 and 21, the rainwater storage tanks according to Examples 1 to 9 can be sloped so as to gently incline vertically downwards from the water inlet side to the outlet side, and the degree of the slope can be selected according to the terrain and location where the rainwater storage tank is constructed. [Explanation of Symbols]

[0030] 1 top plate 2 Intermediate column member 2a Intermediate column member of row A 2b Intermediate column member of column B 3 bottom plate 3a Bottom plate of column A 3b Bottom plate of column B 4 Wall components 4a Wall member of column A 4b Wall members in column B X groove I groove

Claims

1. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is The intermediate column members supporting the top plate covering the water storage space are not adjacent to each other in the longitudinal direction. Arranged in a multi-unit configuration A rainwater storage tank characterized by the following features.

2. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is The intermediate column members supporting the top plate covering the water storage space are not adjacent to each other in the longitudinal direction. Between adjacent intermediate column members in the longitudinal direction, a base plate is placed, or instead of a base plate, cast-in-place concrete is poured. Arranged in a multi-unit configuration A rainwater storage tank characterized by the following features.

3. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is A wall member enclosing the water storage space, a top plate covering the water storage space enclosed by the wall member, an intermediate column member supporting the top plate, and a bottom plate positioned between the intermediate column members in a direction perpendicular to the longitudinal direction of the intermediate column member, It consists of, The intermediate column members supporting the top plate covering the water storage space are not adjacent to each other in the longitudinal direction. The base plate is placed between adjacent intermediate column members in the longitudinal direction. Arranged in a multi-unit configuration A rainwater storage tank characterized by the following features.

4. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is A row A consisting of wall members surrounding the water storage space, a top plate covering the water storage space enclosed by the wall members, A intermediate column members supporting the top plate, and A bottom plate positioned between the A intermediate column members in a direction perpendicular to the longitudinal direction of the A intermediate column members, A row B consisting of a wall member enclosing the water storage space, a top plate covering the water storage space enclosed by the wall member, a B intermediate column member supporting the top plate and positioned not adjacent to the A intermediate column member in the longitudinal direction of the A intermediate column member, and a B bottom plate positioned between the B intermediate column members in a direction perpendicular to the longitudinal direction of the B intermediate column member, It is composed of, The precast box culverts in rows A and B are arranged alternately in a multi-unit configuration so that they do not adjoin the intermediate column members of rows A and B in the longitudinal direction. A rainwater storage tank characterized by the following features.

5. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is A row A consisting of wall members surrounding the water storage space, a top plate covering the water storage space enclosed by the wall members, A intermediate column members supporting the top plate, and A bottom plate positioned between the A intermediate column members in a direction perpendicular to the longitudinal direction of the A intermediate column members, A row B consisting of a wall member enclosing the water storage space, a top plate covering the water storage space enclosed by the wall member, a B intermediate column member supporting the top plate and positioned not adjacent to the A intermediate column member in the longitudinal direction of the A intermediate column member, and a B bottom plate positioned between the B intermediate column members in a direction perpendicular to the longitudinal direction of the B intermediate column member, It is composed of, The precast box culverts in rows A and B are arranged alternately in a multi-unit configuration so that they do not adjoin the intermediate column members A and B in the longitudinal direction. The intermediate column member A of column A and the base plate B of column B are rigidly connected in a state where they are adjacent to each other in the longitudinal direction of the intermediate column member A. The intermediate column member B of row B and the base plate A of row A are rigidly connected in a state where they are positioned adjacent to each other in the longitudinal direction of the intermediate column member B. A rainwater storage tank characterized by the following features.

6. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is A row A consisting of wall members surrounding the water storage space, a top plate covering the water storage space enclosed by the wall members, A intermediate column members supporting the top plate, and A base plate positioned between the A intermediate column members, A row B consisting of a wall member enclosing the water storage space, a top plate covering the water storage space enclosed by the wall member, a B intermediate column member supporting the top plate and positioned not adjacent to the A intermediate column member, and a B bottom plate positioned between the B intermediate column members, It is composed of, The precast box culverts in columns A and B are They are arranged alternately in multiple rows in the direction of the opening, A recess is formed in the top surface of the A and B base plates, along the direction of the box culvert's opening. A rainwater storage tank characterized by the following features.

7. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is A row A consisting of wall members surrounding the water storage space, a top plate covering the water storage space enclosed by the wall members, A intermediate column members supporting the top plate, and A base plate positioned between the A intermediate column members, A row B consisting of a wall member enclosing the water storage space, a top plate covering the water storage space enclosed by the wall member, a B intermediate column member supporting the top plate and positioned not adjacent to the A intermediate column member, and a B bottom plate positioned between the B intermediate column members, It is composed of, The precast box culverts in columns A and B are They are arranged alternately in multiple rows in the direction of the opening, Grooves X are formed diagonally on the top surfaces of base plates A and B. The groove X is continuous along the opening direction of the box culverts in rows A and B, which are arranged alternately in a multi-series configuration. A rainwater storage tank characterized by the following features.

8. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is A row A consisting of wall members surrounding the water storage space, a top plate covering the water storage space enclosed by the wall members, A intermediate column members supporting the top plate, and A base plate positioned between the A intermediate column members, A row B consisting of a wall member enclosing the water storage space, a top plate covering the water storage space enclosed by the wall member, a B intermediate column member supporting the top plate and positioned not adjacent to the A intermediate column member, and a B bottom plate positioned between the B intermediate column members, It is composed of, The precast box culverts in columns A and B are They are arranged alternately in multiple rows in the direction of the opening, A groove I is formed along the opening direction of the box culvert at the edge portion of the base plate A and the base plate B that abuts against the intermediate column member A or the intermediate column member B. The groove I is continuous along the opening direction of the box culverts in rows A and B, which are arranged alternately in a multi-series configuration. A rainwater storage tank characterized by the following features.

9. A rainwater storage tank constructed by arranging multiple precast box culverts in an open direction within a water storage area, The precast box culvert in question is A row A consisting of wall members surrounding the water storage space, a top plate covering the water storage space enclosed by the wall members, A intermediate column members supporting the top plate, and A base plate positioned between the A intermediate column members, A row B consisting of a wall member enclosing the water storage space, a top plate covering the water storage space enclosed by the wall member, a B intermediate column member supporting the top plate and positioned not adjacent to the A intermediate column member, and a B bottom plate positioned between the B intermediate column members, It is composed of, The precast box culverts in columns A and B are They are arranged alternately in multiple rows in the direction of the opening, A groove I is formed along the opening direction of the box culvert at the edge portion of the base plate A and the base plate B that abuts against the intermediate column member A or the intermediate column member B. Grooves X are formed diagonally on the top surfaces of base plates A and B. The grooves I and X are continuous along the opening direction of the box culverts in rows A and B, which are arranged alternately in a multi-series configuration. A rainwater storage tank characterized by the following features.

10. The intermediate column member A of row A and the base plate B of row B are rigidly connected. The intermediate column member B of row B and the base plate A of row A are rigidly connected. A rainwater storage tank according to any one of the features 1 to 9.

11. The precast box culverts in columns A and B are Rainwater storage tanks arranged alternately in multiple rows in the direction of their openings, It slopes vertically downwards from the water inflow side to the water outflow side. A rainwater storage tank according to any one of the features 1 to 9.

Images