JP3999990B2 - Underground water tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an underground water storage tank that stores rainwater in an underground water reservoir space, temporarily accumulates rainwater and slowly permeates it into the ground, or discharges it into a river or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an underground water tank is known in which a large number of filling members are arranged in a horizontal direction and stacked in a vertical direction in an underground water reservoir space. Various techniques have been proposed for filling members filled in the underground water storage tank.
Underground water tanks are buried underground in urban parks, plazas, sidewalks, etc., and are mainly used to store rainwater. If rainwater is once stored in the underground water tank during heavy rain, the amount of water flowing into the river at a time decreases, so that it is possible to prevent the river level from rising rapidly. Rainwater stored in underground water tanks can also be used for irrigation to park green spaces, watering grounds, fire-fighting water, emergency water for daily use.
[0003]
[Problems to be solved by the invention]
In an underground water tank filled with a filling member, a downward (vertical) earth pressure (sediment pressure) is applied to the ceiling, and a lateral (horizontal) earth pressure is applied to the periphery.
The magnitude of these earth pressures often varies depending on the construction site conditions, such as the shape and structure of the underground water tank, and the ground. Further, the horizontal earth pressure changes at every depth where the member is installed, and the horizontal strength required for the filling member also changes accordingly.
On the other hand, since the filling member is a molded product having a predetermined shape, the strength in the vertical direction and the strength in the horizontal direction are almost constant for each filling member. Therefore, it has been difficult to arbitrarily set the strength in the vertical direction and the strength in the horizontal direction of the filling member according to the situation at the construction site. For this reason, the strength of the filling member may be insufficient with respect to the required strength, or may be excessive.
In addition, since there are many filling members to be filled in the underground water tank, it takes time and effort to install the filling members.
[0004]
The present invention has been made in order to solve such a problem, and the vertical strength and the horizontal strength in the space forming means provided in the underground water storage tank in order to form a water reservoir space in the ground. The purpose is to provide an underground water tank that can be set arbitrarily according to the situation of the construction site.
[0005]
[Means for Solving the Problems]
  In order to achieve the above-mentioned object, an underground water storage tank according to the present invention is an underground water storage tank provided with space forming means for forming a water storage space in the ground, and the space forming means is in a vertical direction. A plurality of columnar members arranged in parallel with each other and almost regularly across the water reservoir space, and a plurality of columnar members arranged in a row at a joint portion, and at least one direction that is substantially horizontal. A plurality of horizontal bar-like members arranged in parallel to each other and almost regularly in the whole of the water reservoir space to form a combined frame structureThe joining member configured and disposed in the joining portion joins the opposing columnar members in a straight line, joins the opposing horizontal bar members in a straight line in the horizontal direction, and the columnar member And the horizontal bar-like member are joined to each end of the columnar member and the horizontal bar-like member in the outer periphery of the water reservoir space, respectively, at the bottom, side and ceiling of the water reservoir space. The outer plate member is attached, and a plurality of recesses are arranged almost regularly in the entire outer plate member, and the end portions of the columnar member and the horizontal bar-shaped member are the recesses. Is engaged and supported.
  The plurality of horizontal bar-shaped members include a plurality of parallel first horizontal bar-shaped members and a plurality of parallel second horizontal bar-shaped members whose central axes are substantially perpendicular to each other, and the columnar members, It is preferable that the first horizontal bar-shaped member and the second horizontal bar-shaped member are joined at the joint portion in three directions substantially perpendicular to each other.
  The plurality of horizontal bar-shaped members further include a plurality of parallel third horizontal bar-shaped members that face at least one direction that is inclined at a predetermined angle in a horizontal plane with respect to one of the horizontal bar-shaped members. It is preferable that the horizontal bar member is joined to the columnar member at the joint.Yes.
GoodPreferably, the columnar member and the horizontal bar-shaped member are constituted by a pipe, and a through-hole for allowing water to freely pass therethrough is formed in the peripheral surface of the pipe.
  In addition, the case where the said columnar member and the said horizontal direction rod-shaped member are comprised with the shape steel which has predetermined | prescribed cross-sectional shape may be sufficient.
  Moreover, it is preferable that a large number of through holes are formed in the outer plate member throughout.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of an embodiment according to the present invention will be described with reference to FIGS.
(First embodiment)
1 to 8 are views showing a first embodiment. 1 is a longitudinal sectional view of the underground water tank, FIG. 2 is a perspective view showing a part of the space forming means of the underground water tank, FIG. 3 is a perspective view showing a part of the space forming means, and FIG. FIG. 4B is a sectional view showing the joining portion of FIG. 3, and FIG. 4C is a sectional view showing a modification to FIG. 4B.
[0007]
As shown in FIGS. 1 and 2, in the underground water storage tank 1 of the present invention, the water reservoir space 3 is formed in the ground by digging down the ground 2 and providing the space forming means 4. For convenience of explanation, a direction perpendicular to the ground 2 is defined as a Y direction, and substantially horizontal directions orthogonal to the Y direction and orthogonal to each other are defined as an X direction and a Z direction.
An outer plate member 8 is disposed on the bottom portion 5, the side portion 6, and the ceiling portion 7 of the water reservoir space 3. The periphery of the outer plate member 8 disposed on the bottom portion 5 and the side portion 6 is covered with a water shielding sheet 9.
The outer plate member 8 is divided into a predetermined shape (here, a rectangular shape) and laid side by side. The outer plate member 8 functions as a partition plate for partitioning the water reservoir space 3 and the surrounding earth and sand and receiving earth pressure. A large number of through holes 12 are formed in the outer plate member 8 throughout.
The material of the water-impervious sheet 9 is preferably a rubber excellent in aging resistance, oxidation resistance, and water resistance, such as ethylene-propylene rubber (EPDM), but may be a synthetic resin such as polyethylene and polyvinyl chloride. Good.
The water-impervious sheet 9 is previously formed in a predetermined shape so as to cover the periphery of the water reservoir space 3. Protection sheets 10 and 11 formed of a water-permeable nonwoven fabric or the like are provided on the inner and outer sides of the water-impervious sheet 9, respectively. In the ceiling portion 7, only the outer plate member 8 is provided, and the water-impervious sheet 9 and the protective sheets 10 and 11 are not provided.
[0008]
The bottom 5 of the water reservoir space 3 has a smooth surface without unevenness by laying sand on crushed stone and laying a plate material 13 made of synthetic resin on the sand layer. The outer plate member 8 is spread on the plate member 13 via the outer protective sheet 11, the water-impervious sheet 9, and the inner protective sheet 10, and the space forming means 4 is installed on the outer plate member 8.
The space forming means 4 has a skeleton structure made of synthetic resin, and a space for water reservoir is formed between members constituting the skeleton structure, and the interior of the member itself is also a space for water reservoir. It has become. The inside and outside gaps of these members communicate with each other to form a large gap portion 14 as a whole.
The space forming means 4 is made of hard synthetic resin such as polypropylene, polyethylene, acrylonitrile-butadiene-styrene copolymer (ABS), polyvinyl chloride, and fiber reinforced plastic (FRP), and each component is injection molded and extruded. Each is integrally formed by molding or the like.
[0009]
An inflow pipe 16 is provided on the upper portion of the side portion 6 of the underground water tank 1. The inflow pipe 16 is a pipe for allowing inflow water 15 such as rainwater to flow into the underground water storage tank 1 and communicates with the gap portion 14.
An outflow pipe 18 is provided at the lower portion of the side portion 6. The outflow pipe 18 communicates with the gap 14 in order to allow rainwater or the like stored in the underground water storage tank 1 to flow out as outflow water 17. The inflow pipe 16 and the outflow pipe 18 may be provided on the ceiling portion 7 and the bottom portion 5, respectively.
Using this underground water storage tank 1, for example, rainwater collected on the roof of a building can be introduced from the inflow pipe 16 into the water reservoir space 3 to be stored and discharged from the outflow pipe 18. The effluent water 17 is discharged into a river or the like, or used for irrigating a park green space.
In the underground water storage tank 1 shown in FIG. 1, the ceiling portion 7 is not covered with the water-impervious sheet 9 and has a non-sealed structure through which rainwater can pass. Accordingly, part of the rainwater that has fallen on the ground surface penetrates the ground and flows into the water reservoir space 3 through the through hole 12 of the outer plate member 8 of the ceiling portion 7.
In addition, if the bottom part 5 of the underground water tank 1 is made into the non-sealing structure which rain water can pass, after rain water is once stored in the underground water tank 1, it can be made to infiltrate slowly into the ground from the bottom part 5. Or you may make the airtight sheet | seat 9 and the protection sheets 10 and 11 also in the ceiling part 7 of the underground water tank 1 so that the whole space formation means 4 may be enclosed and sealed structure.
[0010]
Next, the space forming means 4 will be described.
As shown in FIGS. 2 to 4, the space forming means 4 includes a plurality of columnar members 30 and a plurality of horizontal bar-shaped members 31 and 32, and has a combined frame structure as a whole.
The plurality of rod-shaped members 30 are arranged in the entire water reservoir space 3 in a substantially regular manner in parallel to each other in the vertical direction (Y direction). The plurality of horizontal bar-like members include a plurality of parallel first horizontal bar-like members 31 and a plurality of parallel second horizontal bar-like members 32 whose central axes are substantially perpendicular to each other.
The first horizontal bar-shaped members 31 are joined to the columnar members 30 arranged in a row at the joints 33 and face the substantially horizontal X direction in parallel with each other and almost regularly. Is arranged.
Similarly, the second horizontal bar-like members 32 are joined to the columnar members 30 arranged in a row at the joints 33, facing the substantially horizontal Z direction, parallel to each other and almost regularly. The storage space 3 is arranged throughout.
Thus, the rod-shaped member 30, the first horizontal bar-shaped member 31 and the second horizontal bar-shaped member 32 are bonded at the bonding portion 33 so as to face three directions (Y direction, X direction, Z direction) substantially perpendicular to each other. Has been.
This framework structure is the same (or substantially the same) in the later-described modified example and the second and third embodiments.
In addition, one horizontal bar-shaped member among the first and second horizontal bar-shaped members 31 and 32 is connected by a connecting member (not shown) having sufficient strength, and the other horizontal bar-shaped member is omitted. It may be the case.
[0011]
A joining member 34 is disposed in the joining portion 33. The joining member 34 joins the opposing columnar members 30 in a straight line, joins the opposing first horizontal bar-like members 31 in a straight line, and connects the opposing second horizontal bar-like members 32 to each other. Are joined in a straight line. Further, the joining member 34 joins the columnar member 30, the first horizontal bar-shaped member 31, and the second horizontal bar-shaped member 32 at the joint portion 33.
At the ends of the columnar member 30 and the first and second horizontal bar members 31 and 32 in the outer peripheral part (bottom part 5, side part 6, ceiling part 7) of the water reservoir space 3, there is a bottom part of the water reservoir space 3. 5, the outer-plate member 8 arrange | positioned at the side part 6 and the ceiling part 7, respectively is attached.
A plurality of concave portions 35 are arranged almost regularly in the entire outer plate member 8. The end portions of the columnar member 30 and the first and second horizontal bar members 31 and 32 are engaged with and supported by the recesses 35. Thereby, the columnar member 30 and the first and second horizontal bar members 31 and 32 are positioned and held at predetermined positions so as not to move.
The columnar member 30 and the first and second horizontal bar members 31 and 32 are constituted by a pipe 40 having a circular cross section, and a plurality of through holes 41 for allowing water to freely pass through the peripheral surface of the pipe 40. It is installed.
Thereby, rainwater can be stored also in the internal space of the pipe 40, and the amount of water that can be stored in the underground water storage tank 1 can be increased. The through hole 41 may not be formed.
[0012]
As shown in FIG. 4A, the joining member 34 is integrally formed as a whole by fixing three sockets 42 facing three directions substantially perpendicular to each other. The pipe 40 is fitted into the socket 42 and is locked to the socket 42 by a fixing pin 43. The three sockets 42 may be fixed to each other using a fixing member (not shown) or the like.
In many cases, the pipe 40 is inserted through the socket 42 as shown in FIG. 4 (B). However, as shown in FIG. May be connected. In this case, the pipe 40 is locked to the socket 42 by the fixing pin 43 in the vicinity of the end portion 44.
4 (B) and 4 (C), a hole is formed in the socket 42 and the pipe 40 in advance, and a fixing pin 43 is inserted into the hole to be locked. By doing so, the pipe 40 can be easily attached to the joining member 34 with one touch, and the assembly work of the space forming means 4 is facilitated.
2 to 4, the columnar member 30, the first horizontal bar-shaped member 31, and the second horizontal bar-shaped member 32 are slightly different from each other in the central axis, but are substantially perpendicular to each other. It is joined at the joint 33 in the direction.
[0013]
5 is a perspective view showing a modified example of the space forming means, FIG. 6A is a perspective view showing the joining member 34a of FIG. 5, FIG. 6B is a cross-sectional view showing the joining portion 33 of FIG. (C) is sectional drawing which shows the modification with respect to FIG. 6 (B).
In the joining portion 33 of the space forming means 4a shown in FIG. 5, a joining member 34a (FIG. 6A) having a different configuration is used. In this joining member 34a, the columnar member 30, the first horizontal bar-shaped member 31 and the second horizontal bar-shaped member 32 are directed in three directions substantially perpendicular to each other by their central axes intersecting at one point. Joined at the joint 33.
In the joining member 34a, a pipe-shaped socket 42 is arranged in the vertical direction (Y direction), and the socket 42a is integrally formed in a cross shape in the horizontal direction (horizontal direction) with respect to the socket 42.
The pipe 40 of the columnar member 30 is inserted into the vertical socket 42, and the pipes 40 of the first and second horizontal bar members 31 and 32 are inserted into the horizontal socket 42a.
In this case, as shown in FIG. 6 (B), the fixing pin 43 is used to lock the pipe 40 to the socket 42a, or as shown in FIG. The locking portion 45 may be bent and the locking portion 45 may be engaged with the locked portion 46 formed inside the socket 42a.
According to the configuration shown in FIG. 6C, the labor for attaching the fixing pin 43 is not required, so that the assembling work is further simplified and the number of parts can be reduced.
[0014]
FIG. 7 is a perspective view showing another modification of the space forming means.
In the joining portion 33 of the space forming means 4a1 shown in FIG. 7, no joining member is used. In this case, the pipe 40 constituting the columnar member 30 is integrally united with the pipe 40 constituting the first and second horizontal bar-like members 31 and 32 by the joint portion 33 to form a unit.
Also in the space forming means 4a1, the columnar member 30, and the first and second horizontal bar members 31 and 32 are joined by the joining portion 33 in three directions substantially perpendicular to each other.
[0015]
FIG. 8A is a cross-sectional view showing a joint portion between pipes in a columnar member and a horizontal bar-like member of the present invention, and FIG. 8B is a cross-sectional view showing a modification to FIG. 8A.
In the first embodiment and the second and third embodiments described later, the pipes 40 in the columnar member 30 and the horizontal bar-shaped member are joined as shown in FIG.
For example, as shown in FIG. 8A, both pipes 40 can be fitted and positioned, and both pipes 40 can be connected by a fixing pin 43.
As shown in FIG. 8B, the locking portion 45 formed at the end of one pipe 40 is engaged with the locked portion 47 formed inside the other pipe 40. It may be.
[0016]
(Second Embodiment)
FIG. 9 to FIG. 11 are views showing the second embodiment, FIG. 9 is a perspective view showing a part of the space forming means 4b, FIG. 10 is a plan view showing a part of the space forming means 4b, and FIG. It is a perspective view which shows the space formation means 4c concerning a modification.
The space forming means 4b and 4c shown in FIGS. 9 to 11 have a columnar member 30 and first and second horizontal bar-shaped members 31 and 32, similarly to the space forming means of the first embodiment. ing.
Further, the plurality of horizontal bar-like members of the space forming means 4b and 4c are in a horizontal plane with respect to one horizontal bar-like member (that is, the first horizontal bar-like member 31 or the second horizontal bar-like member 32). And a plurality of parallel third horizontal bar members 50 facing at least one direction oblique at a predetermined angle (for example, 45 degrees). The third horizontal bar member 50 is joined to the columnar member 30 at the joint portion 33.
[0017]
In the case of the space forming means 4b shown in FIGS. 9 and 10, the plurality of third horizontal bar-shaped members 50 are arranged at a predetermined angle θ (for example, 45 in the horizontal plane) with respect to the first horizontal bar-shaped member 31. Degrees) are arranged in parallel with each other in an oblique direction.
The joining member 34b includes three sockets 42 that face in the X, Y, and Z directions, and one socket 42 that is integrally fixed to the two sockets 42 and faces the axial direction of the third horizontal bar-like member 50. have. The joining member 34b is integrally formed as a whole.
Therefore, in the joint part 33 to which the third horizontal bar member 50 is joined, the joint member 34b is used, and the joint part 33 to which the columnar member 30, the first and second horizontal bar members 31 and 32 are joined. Then, the same joining member 34 as in the first embodiment is used. In the third horizontal bar member 50, the same pipe 40 as in the first embodiment is used.
[0018]
In the case of the space forming means 4b shown in FIGS. 9 and 10, the third horizontal bar-like member 50 is disposed obliquely (for example, at an angle θ = 45 degrees) in the horizontal plane. Accordingly, the outer plate member 8 can be disposed obliquely in a plan view on the side portion 6 of the water reservoir space 3 and brought into contact with the end portion 51 of the third horizontal bar-shaped member 50. The outer plate member 8 is preferably arranged at a substantially right angle with respect to the third horizontal bar member 50.
As a result, the outer plate member 8 is supported by a plurality of arranged third horizontal bar members 50, so that the space forming means 4b has sufficient strength against earth pressure.
Note that, as in the space forming means 4c shown in FIG. 11, the third horizontal bar-like member 50 may be joined by the joining member 34c so as to face two directions. In this space forming means 4c, the eight sockets 42a of the joining member 34c branch off at the same angle in the horizontal direction, and the first to third horizontal bar-shaped members 31, 32, 50 that face the four horizontal directions in total are provided. Is provided. All the horizontal bar members 31, 32, 50 are joined to the columnar member 30 and intersect at one point.
According to the space forming means 4b and 4c of the second embodiment, the shape of the underground water storage tank 1 in a plan view can be a polygon or an irregular shape such as a hexagon or octagon other than a rectangle. As a result, the underground water tank 1 can be configured in an arbitrary shape corresponding to the shape of the site.
[0019]
(Third embodiment)
12 and 13 show the third embodiment. FIG. 12 is a perspective view showing a part of the space forming means 4d. FIG. 13 is a perspective view showing a part of the space forming means 4e according to the modification. It is.
In the space forming means 4d shown in FIG. 12, the columnar member 30, and the first and second horizontal bar members 31 and 32 are constituted by a pipe 60 having a rectangular cross section. Note that, similarly to the first and second embodiments, it is preferable that a plurality of through holes for allowing water to freely pass through are formed in the peripheral surface of the pipe 60.
The joining member 34 d has a shape corresponding to the rectangular pipe 60 and is integrally formed as a whole, and is disposed in the joining portion 33. Therefore, the joining member 34d joins the opposing columnar members 30 in a straight line, joins the opposing horizontal bar members in a straight line, and joins the columnar member 30 and the horizontal bar members 31 and 32 together. can do.
In the space forming means 4e shown in FIG. 13, the columnar member 30 and the horizontal bar members 31 and 32 are constituted by a steel plate 61 having a groove shape (a U-shaped cross section). Since the columnar member 30 is open on one side and the horizontal bar members 31 and 32 are open on the lower side, it is preferable because earth and sand do not accumulate in the space forming means 4e. In addition to the groove shape, the shape steel 61 may be a mountain shape (L-shaped cross section), an H shape, or the like.
[0020]
The plurality of columnar members 30 in the space forming means 4, 4 a, 4 a 1, 4 b to 4 e of the first to third embodiments face the vertical direction in parallel to each other and almost regularly in the entire water reservoir space 3. The plurality of horizontal bar-shaped members are joined to the columnar members 30 arranged in a row at the joint portion 33, and are substantially parallel to each other in a substantially horizontal direction and are regularly arranged in the water reservoir space 3. It is arranged in the whole. Since the space forming means has a combined frame structure as a whole, it is possible to set a sufficient strength against earth pressure.
At the joint portion of each member in the space forming means 4, 4 a, 4 a 1, 4 b to 4 e, the tensile force is small and mainly the compressive force acts, so the joint portion has sufficient strength to withstand the compressive force.
Regarding the strength in the vertical direction in the space forming means 4, 4 a, 4 a 1, 4 b to 4 e for forming the water reservoir space 3, the material, shape, structure, thickness, pitch between members, etc. of the columnar member 30 are arbitrarily set. can do. Similarly, regarding the strength in the horizontal direction, the material, shape, structure, thickness, pitch between members, etc. of the first to third horizontal bar members 31, 32, 50 can be arbitrarily set. .
As a result, the vertical strength and horizontal strength of the space forming means 4, 4 a, 4 a 1, 4 b to 4 e are determined according to the construction site conditions such as the shape and structure of the underground water storage tank 1, the ground, or the filling member The strength of the filling member can be set individually and arbitrarily for each installation position.
In general, since a higher strength is required in the vertical direction than in the horizontal direction, for example, the diameter of the columnar member is preferably larger than that of the horizontal bar-shaped member.
[0021]
In the underground water storage tank 1 of the present invention, the columnar member and the horizontal bar-shaped member may be joined together at the joining portion, so that the assembly work is easier than in the conventional filling member, and a large porosity is obtained. be able to.
In this way, the underground water tank 1 is easy to construct, has a short construction period, is inexpensive, has excellent earthquake resistance, and the upper part of the underground water tank 1 is backfilled with soil so that it can be used as a park or the like. It can be used effectively.
Since the columnar member 30, the first horizontal bar-shaped member 31, and the second horizontal bar-shaped member 32 are oriented in three directions substantially perpendicular to each other, the substantially rectangular shape surrounded by the three members 30, 31, 32 is formed. The opening is relatively large.
Therefore, the inflow pipe 16 and the outflow pipe 18 arranged on the outer peripheral portion of the water reservoir space 3 can be inserted directly into the water reservoir space 3 through the opening with their diameters increased. As a result, it is not necessary to separately provide an eaves or the like in the vicinity of the inflow portion and the outflow portion of the rainwater in the underground water tank 1, and the structure is simplified.
In the water reservoir space 3, the openings communicate with each other in a straight line, so that water can easily flow through the water reservoir space 3, and maintenance work such as inspection of the water reservoir space 3 and removal of earth and sand is facilitated. It can be carried out.
[0022]
Commercially available products can be used for the pipes and shaped steel for the columnar member and the horizontal bar member, so that the manufacturing cost of the space forming means can be reduced.
In each of the above embodiments, the columnar members 30 are arranged in a lattice shape in a plan view, but may be a case where the columnar members 30 are arranged almost regularly in a staggered manner in a plan view.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and additions are possible within the scope of the present invention.
In the drawings, the same reference numerals denote the same or corresponding parts.
[0023]
【The invention's effect】
  The present inventionThe groundSpace forming means for forming a water reservoir space insideSince the respective end portions of the columnar member and the horizontal bar-shaped member are engaged with and supported by the recesses of the outer plate member, the columnar member and the horizontal bar-shaped member are placed at predetermined positions so as not to move. The space forming means has a combined frame structure as a whole, and the joining members arranged in the joining portion join the opposing columnar members in a straight line and face each other. Since the horizontal bar members are joined in a straight line in the horizontal direction, and the columnar member and the horizontal bar member are joined, sufficient strength against earth pressure is obtained.Can be set.
[Brief description of the drawings]
FIG. 1 to FIG. 8 are views showing a first embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of an underground water storage tank.
FIG. 2 is a perspective view showing a part of the space forming means of the underground water storage tank.
FIG. 3 is a perspective view showing a part of the space forming means.
4 (A) is a perspective view showing a joining member of the space forming means, FIG. 4 (B) is a cross-sectional view showing a joining portion of FIG. 3, and FIG. 4 (C) is relative to FIG. 4 (B). It is sectional drawing which shows a modification.
FIG. 5 is a perspective view showing a modification of the space forming means.
6A is a perspective view showing the joining member of FIG. 5, FIG. 6B is a sectional view showing the joining portion of FIG. 5, and FIG. 6C is a modification to FIG. 6B. FIG.
FIG. 7 is a perspective view showing another modification of the space forming means.
8A is a cross-sectional view showing a joint portion between pipes, and FIG. 8B is a cross-sectional view showing a modification to FIG. 8A.
9 to 11 are views showing the second embodiment, and FIG. 9 is a perspective view showing a part of the space forming means.
FIG. 10 is a plan view showing a part of the space forming means.
FIG. 11 is a perspective view showing a modification of the space forming means.
12 and 13 are views showing a third embodiment, and FIG. 12 is a perspective view showing a part of the space forming means.
FIG. 13 is a perspective view showing a modification of the space forming means.
[Explanation of symbols]
  1 Underground water tank
  3 Puddle space
  4, 4a, 4a1, 4b-4e Space forming means
  5 Bottom
  6 side
  7 Ceiling
  8 Outer plate member
  12 Through hole of outer plate member
  30 Columnar member
  31. First horizontal bar member (horizontal bar member)
  32 Second horizontal bar member (horizontal bar member)
  33 joints
  34, 34a-34d Joining member
  35 recess
  40 pipes
  41 Through hole
  50 Third horizontal bar member (horizontal bar member)
  60 pipes
  61 section steel
  θ Predetermined angle

Claims (6)

An underground water tank provided with space forming means for forming a water reservoir space in the ground,
The space forming means is joined at a joint portion to a plurality of columnar members arranged in the vertical direction in parallel to each other and almost regularly in the entire water reservoir space, and a plurality of columnar members arranged in a row. A plurality of horizontal rod-like members arranged in a substantially horizontal manner in parallel to each other in at least one direction that is substantially horizontal, and configured in a generally combined frame structure. ,
The joining members disposed in the joining portion join the opposing columnar members in a straight line, join the opposing horizontal bar-like members in a straight line in the horizontal direction, and connect the columnar member and the horizontal member. Join the direction bar-shaped member,
At each end of the columnar member and the horizontal bar-shaped member in the outer peripheral portion of the water reservoir space, an outer plate member disposed on the bottom, side and ceiling of the water reservoir space is attached, respectively.
A plurality of recesses are arranged almost regularly in the entire outer plate member, and the respective end portions of the columnar member and the horizontal bar member are supported by being engaged with the recesses. A characteristic underground water tank. The plurality of horizontal bar-like members include a plurality of parallel first horizontal bar-like members and a plurality of parallel second horizontal bar-like members, each center axis being substantially perpendicular to each other,
2. The columnar member, the first horizontal bar-shaped member, and the second horizontal bar-shaped member are joined at the joint portion in three directions substantially perpendicular to each other. Underground water tank. The plurality of horizontal bar-shaped members further include a plurality of parallel third horizontal bar-shaped members that face at least one direction that is inclined at a predetermined angle in a horizontal plane with respect to one of the horizontal bar-shaped members,
The underground water storage tank according to claim 2, wherein the third horizontal bar member is joined to the columnar member at the joint. The columnar member and said horizontal rod-like member is constituted by a pipe, of claims 1 to 3 on the peripheral surface of the pipe, characterized in that the through-hole for passing freely water is bored An underground water tank according to any one of the items. The underground water storage tank according to any one of claims 1 to 3 , wherein the columnar member and the horizontal bar-shaped member are made of steel having a predetermined cross-sectional shape. The underground water storage tank according to any one of claims 1 to 5, wherein the outer plate member has a large number of through holes formed throughout the outer plate member.

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