JP2000045206A - Wet pavement structure and its construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To wet a road surface by a continuous water absorption from a layer by providing the layer for water storage in the whole face under the road surface. SOLUTION: A wet pavement structure is provided with an impervious sheet 10 laid on a roadbed 2 and divides the top from the bottom and a crushed-stone water storage layer 12 laminated on the impervious sheet. The crushed-stone water storage layer 12 is provided with a water absorbing sheet 14 which is so laid as waving in its longitudinal cross section and formed of a nonwoven fabric, a horizontal water absorbing sheet laminated on the water absorbing sheet 14, a sand layer, and a permeable paving material 20 having a water absorbing function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet pavement structure having a function of keeping the surface of a pavement wet, preventing the pavement surface from drying, and suppressing a rise in road surface temperature. About the method.

[0002]

2. Description of the Related Art In recent years, in view of the adverse effects of impermeable pavement,
Permeable pavement is being promoted to promote the penetration of rainwater and air communication, to promote the development of street trees, to reduce the burden on sewers, to prevent urban rivers from flooding, and to recharge groundwater. .

[0003] In this type of permeable pavement, the permeable pavement material typified by permeable asphalt and permeable pavement block has extremely low water retention, so that the absorbed rainwater can be immediately dried by short-time solar radiation. There is a problem that the temperature of the ground surface rises due to the state. In other words, after rainfall, rainwater penetrates into the ground, but water is not retained near the pavement surface, so the pavement surface is easy to dry quickly. The thermal characteristics of non-permeable pavement were the same as those of non-permeable pavement. The high temperature of the pavement surface in summer caused discomfort to people, and in winter the city became a cause of drying.

[0004] The applicant of the present invention has previously led the water in the gutter provided at the end of the water-permeable pavement having a water-absorbing function to the water-permeable pavement, to keep the road surface in a wet state with this water, and to reduce the latent heat of evaporation. A method of cooling the road surface by using is proposed. FIG.
The pavement structure is shown, 1 is a subgrade, 2 is a subbase laid on an upper portion of the subgrade 1, and a submerged sheet 3a or a water-permeable sheet 3b having no capillary water guide power and a nonwoven fabric are provided on the subbase 2. And a water-absorbent sheet 4 made of a water-permeable pavement material 6 having a water-absorbing function on the water-absorbent sheet 4 via a sand layer 5.
By laying the road surface.

A side groove 7 is provided along the end of the above-mentioned pavement structure, and the side groove 7 is closed by a water-permeable lid 8.
The side edge of the side groove protrudes, and this hanging lower end is immersed in the inner bottom surface of the side groove 7 as the water guiding member 4a.

According to this system, when there is rain on the road surface, rainwater passes through the pavement material 6, the sand layer 5, and the water-absorbing material 4 when the water-impermeable sheet 3a is used, and the water is not permeable to capillary water. When the sheet 3b is used, excess rainwater permeates underground through the roadbed 2 and the roadbed 1. Part of the rainwater is stored in the gutter 7 through the lid 8, and excess water is drained to a culvert or the like. When the road surface and the lower layer are in a dry state, a part of the rainwater accumulated in the side groove 7 is absorbed by the water guiding member 4a, and the water diffuses horizontally over the entire surface of the water absorbing sheet 4 located on the roadbed 2 due to the capillary phenomenon. Further, the diffusion water keeps the road surface wet through the sand layer 5 and the pavement material 6 and evaporates sequentially from the road surface.
Cool the road.

Therefore, according to an actual measurement example using this system, even when a normal dry pavement surface is close to 60 ° C. in summer, the temperature of the ground surface can be suppressed to about 30 ° C. In addition, because part of rainwater is taken in and circulated naturally, equipment costs etc. may be inexpensive, and by applying this wet pavement system to places where people gather such as sidewalks, open vacant lots, parks, event venues, leisure lands, etc. The rise in temperature on the ground surface is suppressed, and the reflection and radiant heat from the pavement surface can be reduced, and a comfortable environment can be obtained.

[0008]

However, this structure has the following technical problems. First,
If the sunny weather continues, the rainwater stored in the gutter is insufficient, and it is necessary to newly absorb water.However, even when it is desired to quickly wet with new water absorption, wet it from the end of the nonwoven fabric in order. Therefore, there was a disadvantage that it took time to wet the entire surface.

Also, since the water absorbing portion from the side groove 7 is not a culvert, organisms are easily generated and dirt is likely to be formed. Further, when a large area is constructed, the number of water storage tanks increases, so that cost is reduced. Was also disadvantageous in terms of design.

The present invention has been made to solve the above problems, and has a wettability in which a layer for storing water is formed on the entire lower surface of a road, and the road is moistened by continuous water absorption from this layer. A pavement structure and a method for constructing the same are provided.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a water storage sheet comprising a water impervious sheet laid on a roadbed and crushed stone having a large porosity scattered on the water impervious sheet. Layer, a water-absorbing sheet made of a nonwoven fabric laid so as to undulate in a vertical section over the entire surface of the crushed stone reservoir, and a horizontal water-absorbing sheet laminated on the water-absorbing sheet, a sand layer, and a water-permeable material having a water-absorbing function. And a pavement material. Therefore, in the present invention, the entire lower part of the road surface becomes a crushed stone reservoir, and when the road surface is dried, according to the evaporation and diffusion of water, a capillary phenomenon of a water-absorbing sheet made of a nonwoven fabric laid so as to undulate in a vertical section in the crushed stone reservoir, The water stored in the reservoir is pumped onto the road surface to keep the road surface moist. Also, when it rains, contrary to the above, rainwater permeates into the water reservoir through the water-permeable pavement member having the water absorbing function and the water absorbing sheet, and is stored here.
The amount of water stored in the reservoir is calculated as total construction area x thickness x porosity of crushed stone /
100, a sufficient water storage amount can be secured under the road surface without separately providing a water supply facility.

Here, in the present invention, the water-absorbing sheet made of a nonwoven fabric laid so as to undulate in the longitudinal section is
In the crushed stone water storage tank, a hole for promoting water permeation in the horizontal direction may be formed at an appropriate position.
In this case, the water passes through the hole of the water absorbing sheet,
Water permeation in the horizontal direction in the crushed stone water storage tank is promoted, and the entire surface of the road surface can be quickly kept wet.

Further, in the construction method of the present invention, a water-impervious sheet is laid on a roadbed, crushed stone having a high porosity is scattered on the water-impervious sheet, and the crushed stone is raised into an uneven shape. A water-absorbing sheet made of non-woven fabric is laid so as to undulate along, and the crushed stone is scattered in a valley portion of the water-absorbing sheet to form a crushed stone reservoir in which the water-absorbing sheet is buried. Spreading on a roadbed characterized by laminating a horizontal water-absorbing sheet, a sand layer, and a water-permeable pavement material having a water-absorbing function on a spread crushed stone reservoir layer A sheet, a water reservoir made of crushed stone having a large porosity scattered on the water-impervious sheet, and a water-absorbing sheet made of a nonwoven fabric laid so as to undulate in a vertical section over the entire surface of the crushed stone water reservoir, Water absorption It is characterized in that a water-permeable paving material laminated on over and. In the present invention, construction can be performed by a construction method similar to that for ordinary road pavement, except that a water-blocking sheet, crushed stone, and a water-absorbing sheet are required.

[0014]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing a wet pavement structure according to the present invention. The same components as those of the structure shown in the conventional example are denoted by the same reference numerals, and only different components will be described using different reference numerals.

In FIG. 1, reference numeral 1 denotes a subgrade, and 2 denotes a subgrade made of crushed stone or the like. A water-blocking sheet 10 is laid on the roadbed 2, and the top and bottom are partitioned by the water-blocking sheet 10.
A water storage layer 12 made of crushed stone having a high porosity is filled on the water-impervious sheet 10, and a first water-absorbing sheet made of a nonwoven fabric laid in the crushed stone storage layer 12 so as to undulate in a vertical cross section over the entire surface thereof. 14 are buried. A second water-absorbing sheet 16 also made of a nonwoven fabric is laid on one side of the chevron of the water-absorbing sheet 14 so as to overlap with the top.

On the second water-absorbing sheet 16, a cushion layer 18 made of a sand cushion or a dry mortar is used.
Are laminated, and a water-permeable pavement material 20 having a water-absorbing function (hereinafter, simply referred to as “water-absorbent pavement material”) 20 serving as a road surface is provided on the cushion layer 18.

The water-absorbent pavement material 20 is constructed so as to have a predetermined gradient, and the rain that has fallen on the road surface is absorbed into the inside of the pavement material 20 at the same time as the water collecting pavement buried at the end. The design is such that water flows toward the slit (or side groove) 22. A water supply / drainage pipe 24 is connected to the slit 22 so that water supply / drainage is performed according to the amount of water in the crushed stone reservoir 12.

Reference numeral 26 denotes a water supply / drainage pipe which is on the impermeable sheet 10 and penetrates through the crushed stone reservoir 12. This water supply / drainage pipe 26 is a perforated pipe, and has the same function as the slit 22 described above. It has a function to supply water into the crushed stone reservoir 12 from an external water absorption facility (not shown) at the time of drought, and to discharge the water in the crushed stone reservoir 12 when it is desired to discharge the water. Desirably, automatic opening / closing valves are provided upstream and downstream of the crushed stone reservoir 12 by opening and closing the valves in response to the output of a water amount sensor or the like. The water supply / drainage pipes 24 and 26 may be provided as shown in the drawing, or may be provided with only one of them, depending on the necessity. In the above configuration, at the time of road surface drying, the water stored in the crushed stone water reservoir 12 is pumped up by the capillarity of the first and second water absorbing sheets 14 and 16, and this water is supplied to the cushion layer 18 and the water absorbing pavement 20. It exudes on the road surface through the gap.

Particularly in summer, the road surface is heated, and the exuded water evaporates and diffuses, and the road surface is cooled to an appropriate temperature by the latent heat of evaporation. Since the amount of water pumped by the capillary phenomenon occurs according to the degree of diffusion of water, the amount of water pumped becomes large when the temperature is hot and the amount of evaporation is large, and the amount of water pumped decreases when the amount of evaporation is small. Adjust the temperature automatically.
Conversely, when there is rainfall, the rainwater that has poured onto the road surface passes through the water-absorbent pavement material 20, the cushion layer 18, the second and first water-absorbing sheets 16 and 14 in this order, and the crushed stone reservoir 12 It flows inside and is stored here. The total water storage amount is (total area of crushed stone reservoir 12 × construction thickness × porosity / 100), which is a water storage amount according to the road area.

Further, rainfall is severe, and the rainwater that has flowed on the road surface without being absorbed by the road surface passes through the slits 22 to form the crushed stone reservoir 1.
2 and is also stored here. Excessive rainwater is discharged to the outside through a water supply / drain pipe 24 connected to the slit 22 or to the outside through an internal water / drain pipe 26. Crushed stone reservoir 12 through slit 22
The water that has flowed into the water-absorbing sheet 14 gradually moves rightward in FIG. 1 and hits the water-absorbing sheet 14. However, if a hole is formed at an appropriate position of the water-absorbing sheet 14 to promote water permeation in the horizontal direction,
As the water passes through the hole, water permeation in the horizontal direction in the crushed stone reservoir 12 is promoted.
The water diffused in the horizontal direction is absorbed by the entire surface of the pavement material 20 through the water absorbing sheets 14 and 16, and the entire surface of the pavement material 20 can be quickly kept in a wet state.

When the amount of water in the crushed stone reservoir 12 decreases during a drought, water is automatically replenished through the water supply / drain pipes 24 and 26, so that the inside of the crushed stone reservoir 12 is always maintained at the optimum water amount. The water stored in the crushed stone reservoir 12 is pumped through the water absorbing sheet 14 at a plurality of locations in the reservoir 12. Since the water-absorbing sheet 14 is made of a nonwoven fabric having an extremely high water-pumping ability and is provided so as to be wavy in a vertical section over the entire surface of the crushed stone reservoir layer 12, the time until the entire pavement surface is wetted can be shortened.

Next, the procedure for constructing the above wet pavement structure will be described with reference to FIG. First, as shown in FIG.
A water-impervious sheet 10 is laid on one side, and a water supply / drain pipe 26 is provided. Next, as shown in (b), the crushed stone 12 'having a large porosity is scattered on the water-impervious sheet 10 so as to be uneven, and raised, and the first water-absorbing sheet 1 is formed along the uneven shape.
4 is laid. In this state, as shown in (c), the valley covered with the water-absorbent sheet 14 is filled with the same crushed stone 12 'as described above, and the surface is spread by a compaction roller or the like. Thereafter, by laying the second water-absorbent sheet 16 and applying the cushion layer 18 and the water-absorbent pavement material 20, the wet pavement having the cross-sectional shape shown in FIG. 1 is completed.

[0023]

As apparent from the above description, the wet pavement structure according to the present invention has the following advantages.

Since the reservoir is made of crushed stone having a high porosity, a large amount of rainwater can be stored without any other large-scale water supply equipment.

Since one of the water-absorbing sheets is laid so as to be wavy in a vertical section over the entire surface of the water reservoir, it does not take much time until the entire surface of the pavement becomes wet.

Since the water-absorbing sheet is laid in the water storage layer, there is no risk of generation of organisms and contamination.

The construction is simple, low cost, and can be applied to continuous sections.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a wet pavement structure according to the present invention.

FIGS. 2A to 2C are cross-sectional views showing the same construction procedure.

FIG. 3 is a cross-sectional view illustrating a conventional wet pavement structure.

[Explanation of symbols]

 2 Roadbed 10 Water-blocking sheet 12 Crushed stone reservoir 14, 16 Water-absorbing sheet 20 Water-permeable pavement material having water-absorbing function

Claims (3)

[Claims] 1. A water-impervious sheet laid on a roadbed, a water reservoir formed of crushed stone with a high porosity scattered on the water-impervious sheet, and waving in a vertical section across the entire surface of the crushed stone water reservoir. A water-absorbent sheet made of a nonwoven fabric laid as described above, a horizontal water-absorbent sheet laminated on the water-absorbent sheet, a sand layer, and a water-permeable pavement material having a water-absorbing function. 2. The water-absorbing sheet made of a nonwoven fabric laid so as to undulate in the vertical cross section is characterized in that holes for promoting water permeability in the horizontal direction in the crushed stone water storage tank are formed at appropriate places. The wet pavement structure according to claim 1. 3. A water-impervious sheet is laid on a roadbed, crushed stone having a high porosity is scattered on the water-impervious sheet and raised to form an uneven shape, and a nonwoven fabric is wavy along the surface unevenness of the crushed stone. A crushed stone is laid in a valley portion of the water-absorbent sheet to form a crushed stone water reservoir in which the water-absorbent sheet is buried, and the surface of the crushed stone water-reservoir is laid by rolling and leveled. A method of constructing a wet pavement, comprising laminating a horizontal water-absorbent sheet, a sand layer, and a water-permeable pavement material having a water-absorbing function on a crushed stone reservoir to form a road surface.