JP2007291656A - Permeable lid for rainwater storage tank, and rainwater storage facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fully-permeable rainwater storage facilities which enable rainwater from a ground surface to efficiently permeate for underground storage. <P>SOLUTION: In the rainwater storage facilities 10, a plurality of hollow concrete block bodies 11, the wall surfaces of which each have an opening communicating with the outside and which can be vertically stacked, are horizontally and vertically arranged below the ground surface, so as to form a water storage space S under the ground. Side wall portions surrounding the water storage space S are composed of a cut-off wall 12; a bottom wall portion is composed of a gravel layer 13; a ceiling portion comprises a surface layer which is composed of porous concrete with intercommunicating porosities, and a base layer which is composed of polymer cement mortar formed with a through-hole; a portion for connecting the surface layer and the base layer together is formed in such a shape that the through-hole from the base layer communicates with the intercommunicating porosity of the surface layer in a portion facing the through-hole; and other portions are composed of a plurality of permeable lids 1 formed with a connected layer in which the polymer cement mortar of the base layer permeates through the intercommunicating porosities of the surface layer, so as to be integrated with them. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rainwater storage facility using a specific water permeable lid, and in particular, a water permeable structure in which a surface layer made of porous concrete having continuous voids and a base layer made of polymer cement mortar in which through holes are formed are integrated. And a rainwater storage facility using the permeable lid on the ceiling of a rainwater storage tank.

In recent years, the keyword “water circulation” has been introduced from the viewpoint of comprehensive flood control measures, and the spread of rainwater storage facilities has been strongly promoted.
This rainwater storage facility, for example, builds a large-scale water storage space in a park, road basement, etc., temporarily stores rainwater in the case of torrential rain in the water storage space, and then gradually stores water from the water storage space underground. By infiltration, flood control during torrential rain, ensuring normal river flow, further reducing the heat island phenomenon, groundwater recharge, etc.

As the rainwater storage facility, for example, in Patent Document 1, a water conduit that introduces collected rainwater into the interior, a main container that is connected to the water conduit and stores rainwater, and a small container at the bottom that is connected to the main container. A rainwater storage facility having a sub-container in which a hole is formed, wherein the main container and the sub-container are installed in a pothole dug underground, and the gap in the pothole is filled with crushed stone or gravel The facility is disclosed.
Also, in Patent Document 2, a plurality of precast reinforced concrete cylindrical side wall blocks, etc. are stacked in the vertical direction, bottom concrete is placed, and an upper floor block (upper floor) is installed to build a water storage space underground. Then, an infiltration hole is made in the bottom slab concrete, a water collecting basin is installed on the ground surface, the water collecting basin and the water storage space are connected through a water conduit, and rainwater is guided from the ground surface to the underground water storage space. A rainwater storage facility is disclosed in which, after being stored, rainwater gradually stored in the water storage space is infiltrated into the ground through an infiltration hole or the like of bottom slab concrete.
Further, in Patent Document 3, a plurality of water permeable bags filled with a cut product of recycled tires and the like with a predetermined porosity are disposed in an underground space in which the ground is dug into a pit shape. Rainwater that backfills the underground space above the permeable back with a crushed stone layer and a permeable concrete layer, temporarily stores rainwater that permeates from the ground surface within this backfill area within the permeable back, and further permeates the lower ground A storage facility is disclosed.

Japanese Patent Laid-Open No. 9-78671 Japanese Patent Laid-Open No. 11-61953 JP 2001-59257 A

Here, in the rainwater storage facility described in Patent Document 1 or Patent Document 2, since rainwater is guided to the water storage space constructed underground through the water conduit, the diameter of the water conduit is determined how. There is a limit to increasing the number of water pipes or increasing the number of water conduits, and it is not possible to efficiently guide rainwater to the storage space, especially in the case of concentrated heavy rains where a large amount of rain falls temporarily. was there.
Moreover, in the technique described in the above-mentioned Patent Document 3, since the water storage part is formed in the gap such as the cut product of the filled recycled tire, the water storage amount is small for the occupied space, Not only is the water storage rate low, but it is also difficult to confirm the water storage capacity, so there was a concern that rainwater would overflow from the storage facility during concentrated torrential rains, etc.

  On the other hand, when a water storage space is constructed using a concrete block or the like in the basement as described in Patent Document 2, the upper surface as described in Patent Document 3 tries to construct a rainwater storage facility with full water permeability. In such a case, when the vehicle is under the road surface, it receives a large repetitive load from above due to vehicle traffic, etc., and in particular, a cover material with particularly high bending strength is required to be in a state where both ends are supported. Currently, there is no member that can be suitably used as a cover material for a underground rainwater storage tank that can be manufactured at low cost.

  The present invention has been made in view of the actual circumstances of the background art described above, and one of its purposes is an inexpensive rainwater storage tank having high strength, particularly high bending strength, and excellent water permeability. One of the objectives is to provide a fully permeable rainwater storage facility that can efficiently infiltrate rainwater from the surface and store it underground.

In order to achieve the above-described object, the water-permeable lid of the rainwater storage tank according to the present invention integrates a surface layer made of porous concrete having continuous voids and a base layer made of polymer cement mortar in which through holes are formed. In the rainwater storage tank, the coupling portion between the surface layer and the base layer is formed such that a through hole from the base layer communicates with a continuous gap in the surface layer at a portion facing the through hole. The other part was a water-permeable lid of a rainwater storage tank in which a continuous layer of the surface layer was infiltrated with the polymer cement mortar of the base layer to form an integrated bonding layer.
Here, the polymer cement mortar contains at least cement, fine aggregate, polymer emulsion, high-performance water reducing agent, and antifoaming agent from the viewpoint of realizing a water-permeable lid with high strength, particularly high bending strength. This is a preferred embodiment.

In order to achieve the above-described object, the rainwater storage facility according to the present invention has a hollow concrete block body that has an opening communicating with the outside on the wall surface and can be stacked in the vertical direction. A water storage space is formed in the basement by arranging a plurality in the direction, the side wall surrounding the water storage space is formed of a water blocking wall, the bottom wall is formed of a gravel layer, and the ceiling is formed of the water-permeable lid according to the present invention. A rainwater storage facility consisting of multiple units.
Here, it is a preferred embodiment that the water-permeable pavement is provided above the water-permeable lid from the viewpoint that the top of the rainwater storage facility can be used safely and effectively as a park, a road, or the like.

  According to the permeable cover of the rainwater storage tank according to the present invention described above, the surface layer is porous concrete having continuous voids, the base layer has a through hole, and the joint between the surface layer and the base layer is Since the through hole from the base layer is formed so as to communicate with the continuous void in the surface layer at a portion facing the through hole, sufficient water permeability is exhibited. In addition, the bonded portion of the surface layer made of porous concrete and the base layer made of polymer cement mortar penetrates the continuous void of the surface layer into the continuous void of the surface layer except for the portion of the bonded portion that communicates with the through hole from the base layer. The surface layer made of porous concrete with continuous voids is supported and reinforced by a high strength, especially high bending strength base layer made of polymer cement mortar. The strength of the entire water-permeable lid is ensured. Accordingly, it is possible to construct a full-water-permeable rainwater storage facility even in the basement that receives a large repetitive load from above, such as under the road surface.

  Moreover, according to the rainwater storage facility according to the present invention described above, water can be accommodated in the hollow portions of the plurality of hollow concrete block bodies, so that a high water storage rate can be obtained. Since the volume of the hollow portion can be easily calculated, the water storage capacity can be accurately grasped. Furthermore, it is easy to form water storage spaces of various dimensions by connecting hollow concrete block bodies via spacers, and there is no fear of causing ground subsidence due to its light weight. Moreover, since the rainwater storage facility according to the present invention comprises the ceiling portion of the water storage space constructed underground by the arrangement of the hollow concrete block body, the above-described water permeable lid according to the present invention, the upper portion of the water storage space. It is possible to make the entire surface a water permeable part (rain water inflow part), efficiently infiltrate rain water from the ground surface and guide it into the water storage space, and the side wall part surrounding the water storage space from the water blocking wall Because the bottom wall consists of gravel layers, once rainwater is stored, it becomes possible to gradually infiltrate the rainwater underground through the gravel layer on the bottom wall. It is possible to effectively control, secure a normal flow rate of the river, further reduce the heat island phenomenon, recharge groundwater, and the like.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a water-permeable lid of a rainwater storage tank according to the present invention and a rainwater storage facility according to the present invention using the water-permeable cover will be described in detail with reference to the drawings.

  As shown in FIG. 1, a water-permeable lid 1 according to the present invention is obtained by integrating a surface layer 2 made of porous concrete having continuous voids and a base layer 4 made of polymer cement mortar in which through holes 3 are formed. And the joint part of the said surface layer 2 and the said base layer 4 is formed so that the through-hole 3 from the said base layer 4 may connect with the continuous space | gap of the said surface layer 2 of the part facing this through-hole 3, The other part is a two-layered member having a specific bonding part in which a bonding layer 5 in which the polymer cement mortar of the base layer 4 penetrates and integrates into the continuous void of the surface layer 2 is formed.

As the surface layer 2 made of porous concrete having continuous voids, so-called porous concrete which has existed conventionally can be widely used as long as the following conditions are satisfied.
The surface layer 2 made of porous concrete is formed by covering an aggregate made of coarse aggregate such as crushed stone of about 5 to 40 mm with a cement paste and bonding the aggregates together with the cement paste to cure them. In this case, continuous gaps can be formed in the gaps, and a pigment may be added if necessary. Moreover, you may use a pumice, a ceramic aggregate, brick waste, a lightweight aggregate, etc. with a comparable diameter as an aggregate. The cement paste may contain fine or fine aggregates. Further, it may be a polymer cement paste or a polymer cement mortar.

The continuous porosity of the surface layer 2 made of porous concrete is suitably 10 to 40%, and more preferably 15 to 35%. This is because if the continuous porosity is less than 10%, sufficient water permeability performance (for example, a water permeability coefficient of 1 × 10 ⁻² cm / sec or more) cannot be obtained. If the porosity exceeds 40%, it is not preferable because inconveniences occur in appearance, strength, vehicle running performance, and the like.
The “continuous porosity” is a value calculated by the following equation (1).

Continuous porosity (%) = [(V0−V1) / V0] × 100 Expression (1)

Where V0 is the apparent volume of the specimen (cm ³ )
V1: Volume of independent gap between aggregate and binder (cm ³ ) = (AC) / γw
C: Weight in water after leaving the specimen in room temperature water for 24 hours (g)
A: The weight of the specimen after wrapping the specimen measured for weight in water in a cloth for 90 minutes (g) * This is called "surface dry weight".
γw: density of water at room temperature (≈1.0 g / cm ³ )

Moreover, as for each hole diameter in the said continuous space | gap, 2-10 mm is preferable. This is because if the diameter of the pores of the continuous void is too small, clogging is likely to occur, and conversely if too large, the balance between water permeability and strength becomes poor.
The porosity and pore size of the above-mentioned continuous voids can be appropriately adjusted depending on the diameter of the coarse aggregate, the amount of coarse aggregate, the amount of cement paste, and the like.

  Next, the polymer cement mortar forming the base layer 4 according to the present invention includes at least cement, fine aggregate, polymer emulsion, high-performance water reducing agent, and antifoaming agent, and has high strength, particularly high bending strength. This is preferable from the viewpoint of providing a base layer.

  The above cement may be any of ordinary Portland cement, early strength Portland cement, super early strength Portland cement, moderately hot Portland cement, silica cement, blast furnace cement, fly ash cement, etc. In the case of air curing, ordinary Portland cement and early strength Portland cement are preferred, and in the case of steam curing, early strength Portland cement is particularly preferred.

Moreover, the said fine aggregate is not specifically limited, What is necessary is just a fine aggregate normally used for a concrete product. For example, land sand produced in Ogasa, Shizuoka Prefecture (surface dry density 2.60 g / cm ³ ) is exemplified. The particle size of the fine aggregate is preferably 0.15 to 5 mm. The amount of aggregate is preferably 100 to 300 parts by weight with respect to 100 parts by weight of cement.

The polymer emulsion is preferably an acrylic emulsion and an acrylic-styrene emulsion, and more preferably an acrylic emulsion, from the viewpoint of expression of bending strength. The acrylic emulsion can be obtained by emulsion polymerization of a monomer composition containing one or more monomers selected from (meth) acrylic acid ester monomers. As the (meth) acrylic acid ester monomer, butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate are preferable.
The preferable particle diameter of the polymer emulsion is 50 to 400 nm, more preferably 100 to 200 nm. Moreover, as solid content of a polymer emulsion, it is preferable that it is 30-70 mass%, More preferably, it is 45-70 mass%. Furthermore, the viscosity of the polymer emulsion is preferably 200 mPa · s or less, and more preferably 100 mPa · s or less. Moreover, 5-22 mass parts is preferable at solid content (active ingredient) conversion with respect to 100 mass parts of cement, and, as for the compounding quantity of the said polymer emulsion, 8-14 mass parts is more preferable.

  The high-performance water reducing agent may be any high-performance water reducing agent that is not a high-performance AE water reducing agent usually used in concrete, but a high water reducing effect is desirable. For example, a polycarboxylic acid ether type high performance water reducing agent is exemplified. As for the compounding quantity of this high performance water reducing agent, 1-3 mass parts is preferable with respect to 100 mass parts of cement.

Examples of the antifoaming agent include silicone emulsions and special nonionic surfactants. Generally, when a polymer emulsion is mixed into cement mortar, bubbles are generated and entrained with air (bubbles) more than necessary, so an appropriate antifoaming agent is added to create a dense hardened polymer cement mortar. There is a need. The antifoaming agent may be added in advance during the production of the polymer emulsion, or not during the production of the polymer emulsion, but may be added during the mixing of the polymer cement mortar. It can be added and further added when kneading the polymer cement mortar. As for the compounding quantity of this antifoamer, 0.5-7 mass parts is preferable with respect to 100 mass parts of polymer emulsions.
In addition to the above, one or more powders selected from blast furnace slag powder, anhydrous gypsum, fly ash, silica fume, limestone powder, and quartzite powder may be further added to the polymer cement mortar as necessary.

  The polymer cement mortar forming the base layer 4 according to the present invention preferably has self-fluidity from the viewpoint of moldability, and this self-fluidity is mainly due to the combined use of the polymer emulsion and the high-performance water reducing agent. Can be granted. Further, in the present invention, the self-fluidity is preferably such that the mortar enters into the voids of the porous concrete plate due to the weight of the porous concrete plate placed thereon, JIS R 5201-1997. Is preferably 200 to 320 mm, and more preferably 250 to 300 mm. This is because when the flow is less than 200 mm, the fluidity of the polymer cement mortar at the time of freshness is insufficient, and the polymer cement mortar hardly penetrates into the continuous voids of the porous concrete to be joined, and the joint strength with the porous concrete. May be weak. On the other hand, when the flow exceeds 320 mm, the polymer cement mortar easily causes material separation, and the polymer cement mortar portion penetrating into the porous concrete by the material separation has a large water cement ratio, and the bonding strength with the porous concrete is high. After all there is a feeling of weakening.

A through hole 3 is formed in the base layer 4 formed of the polymer cement mortar. The shape of the through-hole 3 is not limited as long as it penetrates the plate surface of the base layer 4 made of polymer cement mortar in the vertical direction. However, the through-hole 3 does not have a corner such as a circle or an ellipse. This is preferable because there is no concentration of stress generated in the corners.
The opening area ratio with respect to the horizontal cross section of the base layer 4 made of polymer cement mortar of the through hole 3 is suitably 0.5 to 50%, and more preferably 2 to 30%. Also, the opening area per through hole 3 is suitably 20 cm ² or more and 50% or less of the horizontal cross-sectional area of the base layer 4, and more preferably 50 cm ² or more. It is preferable that it is 30% or less of the horizontal cross sectional area. This is because when the opening area ratio is less than 0.5%, sufficient water permeability (for example, a water permeability of 1 × 10 ⁻² cm / sec or more) cannot be obtained. When the area ratio exceeds 50%, the strength of the base layer 4 made of polymer cement mortar is lowered. Further, when the opening area per one of the through-holes 3 is a small one less than 20 cm ² , the number of through-holes 3 to be formed increases, and it becomes difficult to form and the through-holes are easily clogged. . Moreover, when the opening area per one through-hole 3 exceeds 50% of the horizontal cross-sectional area of the base layer 4, the intensity | strength of the base layer 4 which consists of polymer cement mortar will fall.

In the joint portion between the surface layer 2 made of porous concrete having continuous voids and the base layer 4 made of polymer cement mortar in which the through holes 3 are formed, the through holes 3 from the base layer 4 face the through holes 3. When the bonding layer 5 is formed so as to communicate with the continuous voids of the surface layer 2 of the surface layer 2, and the other portion is formed by the polymer cement mortar of the base layer 4 penetrating into the continuous voids of the surface layer 2. That is, it has a structure composed of a through hole and a bonding layer.
The thickness of the bonding layer 5, that is, the thickness of the portion where the polymer cement mortar penetrates and integrates into the continuous voids of the porous concrete is preferably 3 to 20 mm, and more preferably 5 to 10 mm. This is because, when the thickness of the bonding layer 5 is less than 3 mm, the adhesive force is insufficient, and the surface layer 2 made of porous concrete and the base layer 4 made of polymer cement mortar easily peel off. Further, even if the thickness of the bonding layer 5 exceeds 20 mm, an increase in adhesive force cannot be expected, which is meaningless.

The water-permeable lid 1 according to the present invention having the above-described configuration of the coupling portion can be manufactured, for example, as follows.
First, the porous concrete board B which comprises the surface layer 2 which has a continuous space | gap is manufactured previously. This porous concrete board B is not limited to any production method, and a wide variety of known methods for producing porous concrete can be used. In addition, the recessed part 6 which the upper end of the convex part T of the formwork K for forming the through-hole mentioned later is fitted in the joint surface with the base layer of this porous concrete board B is formed. The method of forming the recess 6 may be a method of providing a projection for forming the recess 6 in the mold when the porous concrete plate B is manufactured, or may be formed by cutting later.

Subsequently, the polymer cement mortar P forming the base layer 4 is adjusted.
The blending composition of the polymer cement mortar P is, for example, as follows.
・ Portland cement: 801kg / m ³
・ Fine aggregate: 1202 kg / m ³
-Polymer emulsion: 88 kg / m ^{3 in} terms of solid content (active ingredient)
・ High performance water reducing agent: 17.6 kg / m ³
-Antifoaming agent: 5.3 kg / m ³
Water: 164 kg / m ³ (however, polymer emulsion, high performance water reducing agent and
Contains water in antifoam. )

Weigh each material so that it has the above composition, first put Portland cement and fine aggregate into a mixer and stir (knead), then add polymer emulsion, water, high-performance water reducing agent and antifoaming agent. Mix and adjust polymer cement mortar P.

  As shown in FIG. 2, the obtained polymer cement mortar P was placed in a mold K provided with a convex portion T for forming a through hole on the bottom surface of the inner surface. As shown, the porous concrete plate B manufactured in advance is fitted to the concave portion 6 of the porous concrete plate B at the upper end of the convex portion T of the mold K, and the portion to be fitted On the joint surface except for the polymer cement mortar P, the joint layer 5 is formed by penetrating into the continuous voids of the porous concrete plate B. Subsequently, steam curing is performed as necessary, the polymer cement mortar P is sufficiently cured, and then demolded.

With the above manufacturing method, as shown in FIG. 1, the joint between the surface layer 2 and the base layer 4 is such that the through hole 3 from the base layer 4 becomes a continuous gap in the surface layer 2 at a portion facing the through hole 3. The water-permeable lid 1 according to the present invention is obtained in which the connecting layer 5 is formed so as to communicate with each other and the polymer cement mortar of the base layer 4 penetrates into the continuous voids of the surface layer 2 and is integrated. .
The curing can also be produced by a curing method other than steam curing, but steam curing is preferable, and steam curing is more preferable particularly when early-strength Portland cement is used as the cement.

  Next, regarding the thickness of the surface layer 2 made of porous concrete and the base layer 4 made of polymer cement mortar in the water-permeable lid 1 according to the present invention described above, the thickness of the surface layer 2 is 60 to 300 mm. Is preferably 80 to 200 mm, and the thickness of the base layer 4 is suitably 40 to 300 mm, more preferably 50 to 200 mm. That is, when the ceiling part of the rainwater storage facility is constructed by using the water-permeable lid 1 of the present invention, the whole of the water-permeable cover 1 is considered from the load acting on the ceiling part, the durability of the member itself, and the workability. The thickness is preferably 100 to 600 mm. Among them, from the viewpoint of strength, the thickness of the base layer 4 is appropriately 40 to 300 mm, and the remaining thickness portion is a preferable thickness of the surface layer 2.

  Moreover, although the shape dimension of the water-permeable lid 1 which concerns on this invention is naturally decided by the shape dimension of the opening part of the rainwater storage tank which a lid | cover covers, if a plane dimension is too small, it is the characteristics with strong bending strength. Is not fully demonstrated. On the other hand, if it is too large, in order to satisfy the design load, the member thickness increases, the weight increases, and the construction efficiency decreases. Therefore, there is a preferable range. Specifically, it is preferable that the plane dimensions be within a rectangle of about 30 to 500 cm both vertically and horizontally, and more preferably within a rectangle of about 50 to 400 cm.

Furthermore, the strength of the water-permeable lid 1 according to the present invention, in particular the bending strength, differs depending on the strength and thickness of the surface layer and the base layer to be formed, the opening area ratio of the base layer portion, etc. Needless to say, the bending strength of the base layer material used as the reinforcing material for the porous concrete is at least higher than the bending strength of the porous concrete of the surface layer portion. In general, considering that the bending strength of the porous concrete used for the surface layer is less than 5 N / mm ² , the bending strength of the polymer cement mortar used for the base layer is at least 5 N / mm ² , preferably 8 N / mm It is mm ² or more, particularly preferably 12 N / mm ² or more. A sufficient reinforcing effect cannot be expected when the bending strength of the base layer portion is about 5 N / mm ² as in the conventional base layer portion of ordinary concrete. The higher the bending strength of the base layer portion, the greater the merit because the thickness of the base layer portion required when receiving the same load becomes thinner and the member can be made lighter.

In addition, the water permeability coefficient of the water-permeable lid 1 according to the present invention is limited in terms of the opening area ratio of the base layer portion in consideration of strength, and the upper limit thereof is naturally determined. In order to use it suitably, it is at least 1 × 10 ⁻² cm / sec or more, preferably 5 × 10 ⁻² cm / sec or more, particularly preferably 10 × 10 ⁻² cm / sec or more.

Next, the rainwater storage facility according to the present invention using the above-described water-permeable lid according to the present invention will be described.
As conceptually shown in FIG. 4, the rainwater storage facility 10 according to the present invention has a hollow concrete block body 11 that has an opening communicating with the outside on a wall surface and can be stacked in the vertical direction. The water storage space S is formed in the basement by arranging a plurality in the vertical direction and the vertical direction, the side wall portion surrounding the water storage space S is composed of the water blocking wall 12, the bottom wall portion is composed of the gravel layer 13, and the ceiling portion is the above book It is a rainwater storage facility comprising a plurality of permeable lids 1 according to the invention.

As the hollow concrete block body 11 having an opening communicating with the outside on the wall surface and capable of being stacked in the vertical direction, Pokhara (registered trademark of Rita General Planning Co., Ltd.) handled by the present applicant, Tokyo Cement Industry Co., Ltd. ) Can be suitably used.
As shown in FIG. 5, the Pokhara 20 has a cubic outer shape, and has a cylindrical hollow portion 22 having openings 21 on each of six surfaces constituting the cube. It is a hollow concrete block body that is lightweight (unit volume weight 0.40 to 0.45 t / m ³ ) and has a high porosity (porosity of 80% or more).

The structure and construction example of the rainwater storage facility according to the present invention will be described using the Pokhara 20.
First, as shown in FIG. 4, the ground G is dug into a pit shape to form an underground space X, and gravel is spread on the bottom of the underground space X to form a bottom wall portion of the water storage space S. A gravel layer 13 is formed.
The thickness of the gravel layer 13 is suitably 20 to 100 cm, and more preferably 30 to 60 cm. Moreover, about 5-60 mm is suitable for the particle size of the gravel to spread.

Subsequently, a large water storage space S is constructed by arranging a plurality of Pokhara 20 in the horizontal direction and the vertical direction above the gravel layer 13 via the spacers 23.
As shown in FIG. 6, the spacer 23 for connecting the Pokhara 20 includes a T-shaped spacer 23 a that is interposed between the Pokara arranged at the lowermost part or between the Pokara arranged at the outermost circumference, and a corner part. There are three types of spacers 23b, which are L-shaped in a side view interposed between arranged Pokharas, and a spacer 23c in a cross-shaped view in a side view interposed between Pokaras adjacent to each other in the front, rear, left, and right directions. By interposing the spacers 23a to 23c between the Pokharas, a large number of Pokharas 20 can be arranged and stacked in the same plane. In addition, the material of the spacer 23 is generally formed of ordinary concrete. As shown in FIG. 6, the positions of the respective Pokharas 20 are constrained by the spacers 23 a to 23 c so as to form an orderly arrangement in the vertical direction, and the same positional relation is also obtained in the arrangement in the plane direction. can get. Therefore, each Pokhara 20 has all the openings 21 aligned with the other Pokharas 20 located on the six sides of the Pokhara 20, so that all the Pokharas 20 in the layers from the upper layer to the lower layer and in the plane arrangement are inside thereof. A large water storage space S is constructed by communicating with the hollow portion 22.

A side wall portion surrounding the water storage space S constructed by arranging a plurality of Pokhara 20 in the horizontal direction and the vertical direction is constituted by a water blocking wall 12.
The water blocking wall 12 may be constructed by placing ordinary concrete in a formwork, or may have a structure in which a plurality of PC concrete plates are attached and water is stopped by a water shielding sheet as necessary. Furthermore, you may just stick a some PC concrete board.
It should be noted that the water blocking wall referred to in the present invention is not required to be water-stopping that does not completely leak the water in the water storage space S to the outside, as long as it can fulfill the function of temporarily storing the water in the water storage space S. The wall thickness is not limited at all.

Moreover, the ceiling part of the water storage space S is comprised by two or more of the water-permeable covers 1 which concern on this invention explained in full detail previously. Although the water-permeable cover 1 is installed in each rainwater storage tank, a ceiling part is formed when these form one surface.
A water-permeable lid 1 according to the present invention is formed by integrating a surface layer 2 made of porous concrete having continuous voids and a base layer 4 made of polymer cement mortar in which through holes 3 are formed, as described above. The joint portion between the surface layer 2 and the base layer 4 is formed so that the through hole 3 from the base layer 4 communicates with the continuous void of the surface layer 2 in the portion facing the through hole 3, and the other portion Is a structure in which a polymer cement mortar of the base layer 4 penetrates into the continuous voids of the surface layer 2 to form an integrated bonding layer 5.
Since the polymer cement mortar is used as the base layer and the polymer cement mortar penetrates into the bonding layer as described above, the strength is high, especially the bending strength is high. Even when it is placed, it can sufficiently withstand the load from above. Moreover, since it has excellent water permeability due to the continuous voids of the porous concrete and the through-holes of the base layer that are directly connected to the bottom surface of the porous concrete and the voids are not blocked, the entire upper surface of the water storage space S becomes a water permeable portion, and rainwater The rainwater can be guided into the water storage space S by efficiently penetrating the water.

Gravel 14 is laid as needed above the water-permeable lid 1 according to the present invention that constitutes the ceiling portion of the water storage space S, and water-permeable pavement 15 is applied above it as shown in FIG. The
This water-permeable pavement 15 may be performed using water-permeable asphalt, water-permeable concrete, water-permeable block, etc., and the thickness is suitably about 5 to 25 cm, and the water permeability coefficient is 1 × 10 ⁻² to 10 × 10. It is preferably about ⁻² cm / sec. In addition, in the water-permeable cover 1 which concerns on this invention, if high intensity | strength porous concrete with sufficient intensity | strength and high water permeability is used, the upper surface itself of this water-permeable cover 1 can also be used as a road surface.

  The surroundings of the rainwater storage facility 10 are backfilled with gravel 16, and a side groove 17 is provided as necessary. A water guide pipe 18 that guides the water in the side groove 17 into the water storage space S is provided.

By setting it as the rainwater storage facility 10 of the above structures, while being able to accommodate water in the hollow part 22 of the some Pokhara 20 in the water storage space S, while being able to obtain a high water storage rate, Pokhara 20 Since the volume of the hollow portion 22 is easy to calculate, it is possible to accurately grasp the water storage capacity, and since the Pokhara 20 is relatively light, a plurality of the water storage spaces S are arranged to construct a huge water storage space S. Therefore, it is possible to provide a rainwater storage facility that can cope with a heavy rain that is temporarily heavy.
Moreover, since the ceiling part of the water storage space S is composed of a plurality of the water-permeable lids 1 according to the present invention having excellent strength (particularly bending strength) and water permeability, the entire upper surface of the water storage space S becomes a water-permeable part, Rainwater can be efficiently infiltrated to guide rainwater into the water storage space S, and drainage above the water storage space S is good. Moreover, since the side wall part which encloses the water storage space S consists of the water stop wall 12, and the bottom wall part consists of the gravel layer 13, once the rainwater is stored in the water storage space S, the gravel layer 13 of the bottom wall part is gradually formed. It is possible to infiltrate rainwater into the underground through the flood control, flood control during torrential rains, securing a normal river flow rate, further reducing the heat island phenomenon, groundwater recharge, and the like.
Further, the stacked Pokhara 20 serves as a support for the rainwater storage facility 10, and the water storage space S is not deformed or damaged by a load such as earth pressure, and the ceiling of the water storage space S is high. Since it is composed of a plurality of the permeable lids 1 according to the present invention having high strength, particularly bending strength, the upper part of the rainwater storage facility 10 can be used as a park, road, etc. without causing subsidence or depression of the ground surface. It can be used effectively.

  As mentioned above, although the embodiment of the permeable cover of the rainwater storage tank according to the present invention and the rainwater storage facility according to the present invention using the water permeable cover has been described, the present invention is not limited to the embodiment described above. Naturally, various modifications and changes are possible without departing from the scope of the present invention as defined in the claims. In particular, Pokhara (registered trademark) used for construction of the rainwater storage facility according to the present invention can be suitably used as a hollow concrete block body 11 having an opening communicating with the outside on the wall surface and capable of being stacked in the vertical direction. It is mentioned as an example and other various hollow concrete block bodies can be used in the present invention.

It is sectional drawing which showed notionally one structure of the water-permeable cover which concerns on this invention. It is a conceptual sectional view showing one process of manufacturing a water-permeable lid concerning the present invention. It is a conceptual sectional view showing one process of manufacturing a water-permeable lid concerning the present invention. It is sectional drawing which showed notionally one structure of the rainwater storage facility which concerns on this invention. It is the conceptual perspective view which showed an example of the hollow concrete block body used for construction of the rainwater storage facility which concerns on this invention. It is a conceptual perspective view showing an example of constructing a water storage space by arranging a plurality of hollow concrete block bodies in the horizontal direction and the vertical direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water-permeable cover 2 Surface layer which consists of porous concrete 3 Through-hole 4 Base layer which consists of polymer cement mortar 5 Bonding layer 6 Recessed part of porous concrete board 10 Rainwater storage facility 11 Hollow concrete block body 12 Water blocking wall 13 Gravel layer 14 Gravel 15 Permeable pavement 16 Gravel 17 Gutter 18 Water conduit 20 Pokhara (registered trademark)
21 Opening 22 Hollow part 23 Spacer B Porous concrete board P Polymer cement mortar T Convex part to form through hole K Formwork S Water storage space G Ground X Underground space

Claims (4)

  A water-permeable lid of a rainwater storage tank in which a surface layer made of porous concrete having continuous voids and a base layer made of polymer cement mortar with through holes formed therein, wherein the joint between the surface layer and the base layer Is formed such that a through hole from the base layer communicates with a continuous void in the surface layer in a portion facing the through hole, and the polymer cement mortar in the base layer penetrates into the continuous void in the surface layer in the other portion. A water-permeable lid for a rainwater storage tank, wherein an integrated bonding layer is formed.   The water-permeable lid for a rainwater storage tank according to claim 1, wherein the polymer cement mortar contains at least cement, fine aggregate, polymer emulsion, high-performance water reducing agent, and antifoaming agent.   A plurality of hollow concrete block bodies having openings on the wall surface that communicate with the outside and can be stacked in the vertical direction are arranged in the lateral and vertical directions below the ground surface to form a water storage space in the basement, and the water storage space is The rainwater storage facility according to claim 1, wherein the surrounding side wall portion is made of a water blocking wall, the bottom wall portion is made of a gravel layer, and the ceiling portion is made of a plurality of water permeable lids according to claim 1. The rainwater storage facility according to claim 3, wherein a water-permeable pavement is provided above the water-permeable lid.

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