JP2018035602A - Water retentive pavement structure - Google Patents

Abstract

[PROBLEMS] To improve the cooling effect of the road surface temperature and greatly extend the cooling duration of the road surface as compared with the conventional one.
A water passage that is continuous between a roadbed 20, a sand layer 50, and a water-permeable pavement 60 made of a single-grain aggregate 21 having a high porosity, and an upper surface of a water retention cell structure 30 having a pumping function. The water-absorbing sheet 40 and the flat portion 41 of the water-absorbent sheet 40, and the top of the plurality of raised portions 42 formed to protrude from the upper surface of the water-absorbent sheet 40 are in contact with the lower surface of the water-permeable pavement 60, Provide a continuous water passage route that allows water to pass between the water absorbing sheet 40 and the water-permeable pavement 60.
[Selection] Figure 2

Description

  The present invention relates to a water-retaining pavement structure that can be applied to sidewalks, roads, parking lots, and the like, and more particularly to a water-retaining pavement structure that has improved water retention capacity per unit volume while ensuring roadbed strength.

  Water retentive pavement that suppresses the rise in road surface temperature by using the heat of vaporization when water is sucked into the porous pavement to evaporate the water so as to mitigate heat island phenomenon and guerrilla heavy rain countermeasures The structure is known.

A water-retaining pavement structure that absorbs water inside a surface pavement is known.
In this pavement structure, since the water retention amount is small and the cooling duration of the road surface is short, various pavement structures have been proposed to increase the water retention amount by imparting water permeability to the roadbed in order to increase the cooling duration.
In order to give the roadbed water permeability, if a material with high water permeability is used for the roadbed, the roadbed support capacity will be insufficient, and if priority is given to the roadbed support power, the water permeability of the roadbed will be sacrificed. Therefore, it is not suitable for a roadway on which a large load is applied.

Patent Documents 1 to 3 disclose that a pavement structure that imparts water permeability to a roadbed is to retain water by burying various water storage containers in the roadbed.
If it demonstrates with reference to FIG. 6, it is laminated | stacked in order of the roadbed b, the sand layer c, and the water-permeable pavement d on the roadbed a, and the water storage container e is embed | buried under the roadbed b.
The water storage container e is a container made of hard resin or concrete, and is filled with a roadbed aggregate f such as crushed stone to maintain the roadbed function, and is made of a non-woven fabric between the water storage container e and the sand layer c. The separation sheet g is interposed to prevent the sand from falling.
As the roadbed aggregate f, incised crushed stones containing a large amount of fine particles that are easy to compact are generally used.
The water that has permeated through the water-permeable pavement d by rain passes through the lower sand layer c and the water-permeable separation sheet g to reach the road bed b, and the water that has penetrated the road bed b is stored in the water storage container e.
When the road surface temperature rises, the water stored in the water storage container e rises through the gap of the roadbed aggregate f by capillary action, and is further sucked from the separation sheet g to the sand layer c, and finally the water-permeable pavement d As the water evaporates through, the rise in road surface temperature is suppressed.

Japanese Patent Laid-Open No. 9-95903 (FIG. 4) Japanese Patent Laying-Open No. 2005-133458 (FIG. 2) Japanese Patent Laying-Open No. 2007-51463 (FIG. 1)

The conventional pavement structure described above has the following problems.
<1> The maximum water storage amount of the water storage container e is obtained by the volume of the water storage container e + the volume of the roadbed aggregate f × the porosity of the roadbed aggregate f.
Since the porosity of the cut crushed stone which is the roadbed aggregate f is as small as 10% or less, even if the water storage container e has a sufficient volume, the maximum amount of water that can be actually stored is extremely small, and there is room for improvement.
<2> Since the roadbed b and the sand layer c are sufficiently compacted by rolling, the moving speed of the water pumped up in the roadbed b and the moving speed of the water pumped up in the sand layer c are extremely slow. .
Since the movement time of water takes longer in proportion to the movement speed of water, the amount of water necessary for cooling the road surface cannot be sucked up when the temperature of the road surface rises, and the cooling effect cannot be sufficiently exhibited.
<3> Although the conventional water storage container e has a water storage function, it does not have a water pumping function.
For this reason, as the water level in the water storage container e decreases, the water suction performance deteriorates, and water stored in the bottom of the water storage container e may not be sucked up.
<4> As a method of increasing the water retention amount of the roadbed b, there is a method of filling the water storage container e with a soft polymer absorber. However, if a soft polymer absorber is used, the bearing capacity of the roadbed b is reduced. It cannot function as a roadbed layer.
In addition, a pavement structure has been proposed in which porous asphalt is filled in the water storage container e to ensure bearing capacity and water retention, but this pavement structure requires a special water storage container that can withstand high temperatures and increases costs. And many problems such as insufficient support capacity of the roadbed because the asphalt filled in the cell chamber cannot be sufficiently compacted.

The present invention has been made in view of the above points, and an object thereof is to provide at least one of the following water-retaining pavement structures.
<1> The cooling effect of the road surface temperature is improved and the cooling duration of the road surface is greatly extended as compared with the conventional case.
<2> To ensure both the bearing capacity of the roadbed and the increase in water retention.

The present invention is a water retention cell in which a roadbed made of a single-grain aggregate with a high porosity that is sprinkled on the roadbed and a plurality of cell chambers that are embedded over the entire surface of the roadbed and restrain the single-grain aggregate. Laminating a structure, a water absorbent sheet having a pumping function laid on the entire upper surface of the roadbed, a sand layer formed on the upper surface of the water absorbent sheet, and a water-permeable pavement having a water absorbent function formed on the upper surface of the sand layer, A water retention pavement structure configured to allow water to pass between the sand layer and the water permeable pavement, the flat surface of the water absorbent sheet contacting the upper surface of the water retention cell structure having a pumping function, and the upper surface of the water absorbent sheet The top of a plurality of raised parts formed by projecting to the bottom surface of the water-permeable pavement is in contact with the bottom surface of the water-permeable pavement to form a continuous water passage that allows water to pass between the water retention cell structure, the water-absorbing sheet, and the water-permeable pavement. is there.
Practically, No. 6-7 crushed stone is suitable for the single-grain aggregate.
The water retention cell structure and the water absorbent sheet are formed of a water absorbent material.
The raised portion of the water-permeable sheet has a ridge shape or an emboss shape.
The water-retaining cell structure may be either an osmotic container with the lower opening of the cell chamber open or a water-impervious container with the lower opening of the cell chamber sealed.

The present invention has at least one of the following effects.
<1> Since a continuous water passage is formed between the water-retaining cell structure and the water-permeable pavement through the water-absorbing sheet, compared to the route that pumps water from the single-grain aggregate to the sand layer and from the sand layer to the water-permeable pavement. Can pump up to permeable pavement at high speed.
<2> A large amount of water-permeable pavement through two water-passing routes: water-passing route through water-retaining cell structure and water-absorbing sheet of water-absorbing material, and water-passing route through the gap between aggregates constituting the roadbed and sand layer Water can be pumped.
<3> Not only a single particle size aggregate with a high porosity is used as the aggregate for roadbed, but also a large amount of water can be retained throughout the permeable pavement by absorbing water into the water retention cell structure and the water absorbent sheet. .
<4> By the above <2> and <3>, the cooling effect of the road surface temperature is improved, and the cooling duration of the road surface can be greatly extended as compared with the conventional case.
<5> Since a single-grain aggregate with a large porosity can be put into a water-retaining cell structure made of a water-absorbing material in a constrained state and compacted, both the bearing capacity of the roadbed and the increase in the amount of retained water can be achieved. Can do.
<6> Since a water retention cell structure can be formed with an inexpensive water-absorbing material without using expensive concrete or hard resin, water retention pavement can be easily constructed at low cost.

Perspective view of a water-retaining pavement structure according to the present invention with a part broken away Cross section of water retention pavement structure BRIEF DESCRIPTION OF THE DRAWINGS It is illustration explanatory drawing of a water retention cell structure, (A) is explanatory drawing of the water retention cell structure whose cell chamber is a honeycomb shape, (B) is explanatory drawing of the water retention cell structure whose cell chamber is a square, (C) Cell chamber Of the water retaining cell structure It is illustration explanatory drawing of a water absorbing sheet, (A) is explanatory drawing of the water absorbing sheet which formed the protruding part in the lattice pattern, (B) is explanatory drawing of the protruding part formed in cone shape, (C) is an internal cavity. Explanatory drawing of the bulge formed densely without Illustration of water flow route through single grain aggregate and sand layer Explanatory drawing of water flow route through water retention cell structure and water absorption sheet Cross section of conventional water-retaining pavement structure

  Embodiments of the present invention will be described below with reference to the drawings.

<1> Outline of Water Retaining Pavement Structure With reference to FIGS. 1 and 2, the water retentive pavement structure according to the present invention has a road bed 10 in the lowest layer.
The water-retaining pavement structure is composed of a water-permeable roadbed 20 formed in a layer form with at least a single-grain aggregate 21 on the roadbed 10, a non-woven water-retaining cell structure 30 that is embedded in the roadbed 20 and constitutes a water storage container, Nonwoven fabric water absorbent sheet 40 laid on the entire upper surface of the water retention cell structure 30, a water permeability non-adjustable sand layer 50 formed on the upper surface of the water absorbent sheet 40, and a water permeable pavement 60 formed on the upper surface of the sand layer 50. And have.
For example, the layer thickness of the roadbed 20 is 50 to 150 mm, and the layer thickness of the sand layer 50 is 20 to 30 mm.
In the present invention, the water retention cell structure 30 and the water absorbing sheet 40 that are water storage containers are formed of a water absorbent material, and the single particle size aggregate 21 having a large porosity is used as a filler for the water retention cell structure 30, thereby The overall water retention amount of the pavement structure was increased.
Furthermore, in the present invention, by laminating the lower surface of the water absorbent sheet 40 so as to overlap the upper surface of the water retention cell structure 30, and by laminating the upper surface of the water absorbent sheet 40 so as to overlap the lower surface of the water-permeable pavement 60, The sucking time was shortened by increasing the sucking speed of water from the roadbed 30 to the permeable pavement 60.
The main materials are described in detail below.

<2> Aggregate for roadbed In the present invention, as the aggregate for roadbed, a single grain aggregate 21 containing almost no fine particles is used.
The reason why the single-grain aggregate 21 is used as the roadbed aggregate is to increase the water retention amount by the water retention cell structure 30 by increasing the porosity of the roadbed 20.
Since the porosity of the single-grain aggregate 21 is about 30%, the porosity can be improved by a factor of 3 or more compared to a conventional cut crushed stone having a porosity of 10% or less.
Practically, it is preferable to use No. 6-7 crushed stone as the single-grain aggregate 21.

<3> Water retention cell structure The single-grain aggregate 21 has a high porosity, but has a property that it is difficult to compact.
Therefore, the water retaining cell structure 30 having a plurality of cell chambers 31 is used, and the single grain aggregate 21 filled in each cell chamber 31 is constrained to ensure the bearing strength necessary for the roadbed layer. .
The water-retaining cell structure 30 is a substantially honeycomb structure in which a plurality of cell chambers (cell spaces) 31 are formed continuously by surrounding a space with a plurality of side walls and opening up and down, and the whole has water permeability.
The water retention cell structure 30 can be used in any form of an osmotic container with the lower opening of the cell chamber 31 or a water-impervious container with the lower opening of the cell chamber 31 closed. Select according to usage.
When the water retention cell structure 30 is used as an osmotic container, the open lower surface of the water retention cell structure 30 is used by being landed on the road bed 10 and, if necessary, the water retention cell structure 30 and the road floor 10 A filter layer (sand layer) may be interposed between the two.
When the water retention cell structure 30 is used as a water-impervious container, for example, the lower surface of the water retention cell structure 30 is closed with a water-impervious sheet (not shown) laid on the upper surface of the road bed 10. When the roadbed 10 is a hardly water-permeable soil, the open lower surface of the water retention cell structure 30 may be landed on the roadbed 10 and closed.

<3.1> Material of Water Retaining Cell Structure The water retaining cell structure 30 is made of a material having water absorption, and for example, a long-fiber nonwoven fabric represented by a spunbonded nonwoven fabric that is lightweight and convenient to handle is suitable.
As another water retention cell structure 30, a non-woven fabric having water permeability may be attached to the surface of a hard plate serving as a core material by bonding or the like.
As a material of the water retention cell structure 30, a known material other than a non-woven fabric can be used as long as it is a material having sufficient water absorption and strength that can stand alone.
Furthermore, the water retention cell structure 30 may be in a foldable or non-foldable form.

<3.2> Planar shape of water retention cell structure Referring to FIG. 3, the planar shape of the water retention cell structure 30 will be described. Each cell chamber 31 has a hexagonal shape (FIG. 3A) and a rectangular shape (FIG. B)), not limited to polygons such as triangles and pentagons, but includes ridges (FIG. 3B), circles, and the like.

<3.3> Dimensions of the cell chamber of the water retention cell structure The vertical and horizontal dimensions when the water retention cell structure 30 is expanded is selected according to the intended use.
When the single-grain aggregate 21 is No. 6-7 crushed stone, the opening dimension L of each cell chamber 31 at the time of expansion is in the range of 50-120 mm, and the height H is preferably in the range of 50-150 mm.
The opening dimension L and the height H of the cell chamber 31 may be dimensions that do not impair the self-supporting property of the water retention cell structure 30 and the restraining effect of the single-grain aggregate 21.

<3.4> Function of water retention cell structure The water retention cell structure 30 has the following multiple functions.
a) Function as a water storage container.
b) A function of reinforcing the roadbed 20 by restraining the single grain medium filling material 21 accommodated in the cell chamber 31 (reinforcing function of the roadbed).
c) A function of retaining a large amount of water in the water retention cell structure 30 (water retention function).
d) A function of providing a water pumping function to the water retention cell structure 30 to promote pumping from the roadbed 20 to the water absorbing sheet 40 (pumping promotion function).

<4> Water-absorbing sheet The water-absorbing sheet 40 is a single water-absorbing sheet, and includes a flat portion 41 and a plurality of raised portions 42 formed by raising a part of the flat portion 41 in the same direction.
The flat portion 41 is a portion that closes the upper surface of the water retention cell structure 30, and the raised portion 42 is a portion that allows water to pass between the water retention cell structure 30 and the permeable pavement 60.
The raised portion 42 has a height that can penetrate the sand layer 50 and contact the lower surface of the permeable pavement 60.
In this example, the sheet is bent to form a ridge-shaped raised portion 42 in parallel (FIG. 1).
As another form of the raised portion 42, the ridge-like raised portions 42 are crossed to form a lattice pattern (FIG. 4A), or the sheet is partially raised by embossing to form a cone shape. (FIG. 4B).
Further, the inside of the raised portion 42 may remain hollow, but may be formed densely without the inside of the raised portion 42 (FIG. 4C).

<4.1> Material of water-absorbing sheet The water-absorbing sheet 40 is made of a material having water absorption and water permeability, such as a nonwoven fabric.
As long as the water absorption sheet 40 is a material having a higher water absorption rate than the sand layer 50, a known material such as a woven fabric can be used in addition to the nonwoven fabric, and the material can be used regardless of a natural material or a chemical material.

<4.2> Function of water absorbent sheet The water absorbent sheet 40 has the following plural functions.
a) A function for separating the roadbed 20 and the sand layer 50 by preventing the permeation of sand (separation function).
b) A function of retaining water in the water absorbing sheet 40 (water retention function).
c) A function of promoting water suction through the water absorbing sheet 40 (pumping promotion function).
d) A function of promoting the water suction by the sand layer 50 alone by increasing the contact area between the sand layer 50 and the water absorbent sheet 40 (sand layer pumping promotion function).
e) A function of reinforcing the roadbed 20 by sealing the upper opening of the cell chamber 31 so as to restrain the single-grain medium-filling material 21 (reinforcement function of the roadbed).
f) A function to reinforce the sand layer 50 by restraining the single-grain filling material 21 between the water-absorbing sheet 40 and the water-permeable pavement 60 (sand layer pressure-proof reinforcing function).

<5> Water-permeable pavement The water-permeable pavement 60 having a porous structure includes a known water-permeable porous concrete pavement and water-permeable porous asphalt pavement, in addition to an interlocking block pavement in which a plurality of blocks 61 having water permeability or water retention are spread. Etc.

[Construction method]
The construction method of the water-permeable pavement will be described with reference to FIG.

<1> Roadbed Work A water retention cell structure 30 is laid in an expanded state on the upper surface of the roadbed 10. Each cell chamber 31 is sealed at the bottom by the roadbed 10 and the upper opening is open.
After the granular particle aggregate 21 having a large porosity is sprinkled into the inside and outside of the water retention cell structure 30 until the layer thickness is such that the water retention cell structure 30 is substantially hidden, the single particle aggregate 21 is rolled to obtain an appropriate layer thickness. Build the roadbed 20.
The water-retaining cell structure 30 accommodates the single-grain aggregate 21 in a state where all the cell chambers 31 are compacted, and the upper surface of the roadbed 20 without hiding the upper surface of the water-retaining cell structure 30. Is exposed from.
It is technically difficult to compact the single-grain aggregate 21 that has been sprinkled on the road floor 10 without installing the water retention cell structure 30, but by installing the water retention cell structure 30, Since the cell chamber 31 restrains the single grain aggregate 21, it can be effectively compacted.
When the single particle size aggregate 21 is rolled, the single particle size aggregate 21 meshes with each other due to the internal friction angle so that a large force does not act on the water retention cell structure 30. There is no worry about damage.

<2> Construction Work of Water Absorbent Sheet The water absorbent sheet 40 is laid on the upper surface of the roadbed 20 with the plurality of raised portions 42 facing upward.
The lower surface of the flat portion 41 of the water absorbent sheet 40 is in contact with the exposed upper surface of the water retention cell structure 30 and seals the upper opening of each cell chamber 31.
Since the loading load of the sand layer 20 and the permeable pavement 60 described later acts on the upper surface of the water absorbent sheet 40 that seals the upper opening of each cell chamber 31, the restraining effect of the single grain aggregate 21 in the cell chamber 31 is further enhanced. Good roadbed function can be maintained.
In laying the water absorbent sheet 40, it is only necessary to contact the upper surface of the water retention cell structure 30 and the water absorbent sheet 40 so that water can be passed between them.

<3> Sand Layer Forming Process The sand layer 50 is formed by rolling the sand on the upper surface of the water-absorbent sheet 40 up to a layer thickness so that the raised portion 42 is substantially hidden.
In forming the sand layer 50, it is important to expose the tops of the raised portions 42 of the water absorbent sheet 40 from the upper surface of the sand layer 50.
Since the sand sprinkled on the upper surface of the water absorbent sheet 40 is restrained by the side surfaces of the plurality of raised portions 42, it is easy to compact the sand.
Furthermore, the contact surface between the lower surface of the flat part 41 of the water absorbent sheet 40 and the upper surface of the water retention cell structure 30 becomes more reliable by the weight and compaction of the sand layer 50.

<4> Formation Work of Permeable Pavement A porous permeable pavement 60 is constructed on the upper surface of the sand layer 50 to complete the construction in a specific span.
In constructing the permeable pavement 60, the top of the raised portion 42 of the water absorbent sheet 40 exposed from the upper surface of the sand layer 50 is placed on the lower surface of the permeable pavement 60 so that water can pass between the water absorbent sheet 40 and the permeable pavement 60. Make contact.
It is desirable that the top of the raised portion 42 is brought into contact with the permeable pavement 60 in a surface contact state with the lower surface.

[Function of permeable pavement]
The characteristic of a water-permeable pavement structure is demonstrated referring FIG. 2, FIG. 5A, 5B.

<1> Rainwater Reservation / Water Retention The water that has permeated through the permeable pavement 60 due to rain reaches the roadbed 20 through the lower sand layer 50 and the water-permeable water-absorbing sheet 40, and the water that has penetrated the roadbed 20 is a water retention container. It is stored in the cell structure 30.

<1.1> The use of a single grain size aggregate 21 as an aggregate for water retention capacity roadbed in water holding cell structure, significantly increasing the water retention capacity Q ₁ to the total volume of the water holding cell structure 30 is the reservoir be able to.
Specifically, since the porosity can be improved three times or more by using the single-grain aggregate 21 having a porosity of about 30% compared to the conventional cut crushed stone having a porosity of 10% or less, the water retention cell A large amount of water can be retained in the internal space of the structure 30.

<1.2> Amount of water retained by water-absorbing material The water-retaining cell structure 30 and the water-absorbing sheet 40 were formed of a water-absorbing material such as a nonwoven fabric, and the water-retaining cell structure 30 and the water-absorbing sheet 40 were allowed to retain water.
Therefore, the water-permeable pavement structure has not only the water retention amount Q _{1 in} the internal space of the water retention cell structure 30 described above, but also the water retention amount Q ₂ that is absorbed by the water retention cell structure 30 and the water absorption sheet 40 to absorb water. It was possible water retention of large amounts of water in amount of added water capacity _{Q 3} minute _{(Q 1 + Q 2 + Q} 3).
In other words, the water retention capacity per unit volume in the roadbed 20 is significantly increased.
The total amount of water retained by the water-absorbing material increases in proportion to the construction area of the water-permeable pavement.

<2> Road surface temperature rise inhibiting action The upper surface of the water retention cell structure 30 and the water absorbent sheet 40 are in contact with each other so that water can pass therethrough, and water is also passed between the water absorbent sheet 40 and the permeable pavement 60. It is possible to touch.
Therefore, when the road surface temperature rises, water is sucked up to the permeable pavement 60 through the following two water passage routes A and B, and the water evaporates through the permeable pavement 60 to suppress an increase in the road surface temperature. .

<2.1> Water flow route through aggregate gap (Fig. 5A)
In the first water flow route, water is sucked upward through the gap between the single-grain aggregates 21 inside the water retention cell structure 30 (arrow A ₁ ), and passes through the flat portion 41 of the water absorbent sheet 40 from the roadbed 20. Then, water is sucked up into the sand layer 50 (arrow A ₂ ), and further, water is sucked up into the permeable pavement 60 through the sand layer 50 (arrow A ₃ ).

<2.2> Water flow route through water-permeable material (Fig. 5B)
The second water flow route is that water is sucked up from the roadbed 20 to the housing of the water retention cell structure 30 through the gap between the single-grain aggregates 21 (arrow B ₁ ) and then absorbed through the housing of the water retention cell structure 30. It is sucked up to the flat part 41 of the sheet 40 (arrow B ₂ ), and further sucked up to the permeable pavement 60 through the flat part 41 and the raised part 42 of the water absorbent sheet 40 (arrow B ₃ ).
In the present invention, continuous passage that allows water to pass between the water retention cell structure 30, the water absorbent sheet 40, and the permeable pavement 60, separately from the water passage route through the gap between the single-grain aggregate 21 and the fine aggregate of the sand layer 50. A water channel is formed.

<2.3> Water Movement Speed The average water movement speed through the water flow route through the water absorbent material by the water retention cell structure 30 and the water absorbent sheet 40 shown in FIG. 5B, and the roadbed 20 and sand layer 50 shown in FIG. 5A. When the average movement speed of the water by the water flow route through the gap of the aggregate that constitutes the is compared, the former speed is superior to the latter speed. This difference in speed is due to the difference in water movement speed due to capillary action.
Therefore, water can be pumped up to the permeable pavement 60 and evaporated through a water flow route of the water retention cell structure 30 and the water absorbent sheet 40 formed of a water-permeable material in a short time.

<2.4> Amount of pumped water In the present invention, since pumping toward the permeable pavement 60 proceeds in parallel through the above-described two water flow routes, a large amount of water can be sucked up.
Therefore, since an amount of water required for cooling can be supplied to the permeable pavement 60, the cooling effect according to the road surface temperature can be sufficiently exhibited.

<2.5> Cooling Duration of Road Surface As described above, the water-permeable pavement structure of the present invention uses the single-grain aggregate 21 having a large porosity as the aggregate for the roadbed, so that the water retention amount Q of the roadbed 20 _{In addition} to increasing ₁ , the water-retaining cell structure 30 and the water-absorbing sheet 40 formed of a water-absorbing material are also allowed to absorb water so that a large amount of water (Q ₁ + Q ₂ + Q ₃ ) is retained.
Therefore, the cooling duration of the paved road surface 60 can be exhibited over a long period of time.
In particular, since the water retaining cell structure 30 has a pumping function, even if the water level in the water retaining cell structure 30 is lowered, the water suction property is not extremely lowered, and the water accumulated at the bottom of the water retaining cell structure 30 However, it can be sucked up reliably and the waste of water retained in the roadbed 20 can be eliminated.

10 ... subgrade 20 ... subbase 21 ... single grain aggregate 30 ... water retention cell structure 31 ... cell chamber 40 ... water absorbent sheet 41 ... flat portion 42 of the water absorbent sheet .... Raised part 50 of water-absorbing sheet ... Sand layer 60 ... Permeable pavement

Claims (6)

A roadbed made of single-grain aggregate with a large porosity that is sprinkled on the roadbed, and a water retention cell structure that is embedded over the entire surface of the roadbed and forms a plurality of cell chambers that restrain the single-grain aggregate. Laminating a water-absorbing sheet having a pumping function laid on the entire upper surface of the roadbed, a sand layer formed on the upper surface of the water-absorbing sheet, and a water-permeable pavement having a water-absorbing function formed on the upper surface of the sand layer; A water-retaining pavement structure that allows water to pass between permeable pavements,
The flat surface of the water absorbent sheet is brought into contact with the upper surface of the water retention cell structure having a pumping function, and the tops of the plurality of raised portions formed by projecting from the upper surface of the water absorbent sheet are brought into contact with the lower surface of the permeable pavement, A continuous water passage that allows water to flow between the water retention cell structure, the water absorbing sheet, and the water-permeable pavement is formed.
Water-retaining pavement structure.   The water-retaining pavement structure according to claim 1, wherein the water-retaining cell structure and the water-absorbing sheet are formed of a water-absorbing material.   The water-retaining pavement structure according to claim 1 or 2, characterized in that the raised portion of the water-permeable sheet has a ridge shape or an emboss shape.   The water-retaining pavement structure according to claim 1, wherein the single-grain aggregate 21 is No. 6-7 crushed stone.   The water retention pavement structure according to any one of claims 1 to 3, wherein the water retention cell structure is an osmotic container having a lower opening of a cell chamber.   The water retention pavement structure according to any one of claims 1 to 3, wherein the water retention cell structure is a water-impervious container in which a lower opening of a cell chamber is sealed.

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