JPH07138931A - Water pearmeable construction sheet - Google Patents

Abstract

PURPOSE:To enhance a drainage capacity of underground surplus water by fusing a large number of threads with a specific diameter between two unwoven fabrics in parallel and holding permeability in the in-face and thickness directions and determining specifically a permeable factor. CONSTITUTION:A large number of polyester-made threads 3, which are formed in the shape of a disk, an oval and a long hole in the cross section, are laid out substantially in parallel between unwoven fabrics 1 and 2, which are made of polyester long fiber and fused under a three layer structure. Then, this permeable construction sheet takes in surplus water in the Z direction by way of the fabrics 1 and 2 by underground pressure and discharges positively the surplus water thus incorporated in the X direction which is identical to the thread layout direction without returning the surplus water underground. A thickness direction permeability coefficient of the sheet is defined to be 10<-2> to 10 deg.cm/sea. Furthermore, as occasion demands, the threads 3 use a high melting point polymer as a core component and a lower melting point polymer as a sleeve component. This construction makes it possible to enhance a drainage function of underground surplus water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-permeable civil engineering sheet having water permeability in both the in-plane direction and the thickness direction of the sheet, and is mainly used for civil engineering drainage materials, particularly slope protection drainage materials and vertical drain materials. The present invention relates to a sheet material suitable as (vertical drainage material).

[0002]

2. Description of the Related Art Needle punched non-woven fabric has been well known as a drainage material for civil engineering. Further, in order to further improve the water permeability in the in-plane direction, it is known to use a three-dimensional mesh made of multiple yarns as a base material and laminate a nonwoven fabric having water permeability on both sides.

[0003]

However, in the case where a three-dimensional mesh made up of multiple yarns is used as a base material and a nonwoven fabric having water permeability is laminated on both sides, the water permeability coefficient in the in-plane direction does not depend on which direction. , And it was impossible to positively induce excess water in one direction.

An object of the present invention is to allow water permeation in two directions, ie, in-plane direction and thickness direction of a sheet, and to limit the in-plane water permeation direction to one direction. It is in providing the sheet.

[0005]

In order to achieve the above object, the present invention employs the following configurations.

That is, the water-permeable civil engineering sheet of the present invention is
A large number of filaments arranged in parallel between two non-woven fabrics 3
It is characterized by being fused as a layered laminated structure.

There is.

As the non-woven fabric used in the present invention, any non-woven fabric having water permeability may be used, but preferably, various thermoplastic resins such as polyamide, polyester, acryl, polyolefin and polyvinylidene chloride are used. , Polybutylene terephthalate, and those composed of short fibers or long fibers such as copolymers thereof, needle punch, thermal bond, chemical bond, those which are formed into a nonwoven fabric by a molding method such as stitch bond, More preferably, a polyester filament non-woven fabric is used.

It is important that a large number of single yarns are arranged in parallel as the structure of a large number of filaments used in the present invention.
With this structure, the water permeability in the in-plane direction can be limited to one direction. In view of the purpose of limiting the water permeability in the in-plane direction to one direction, this parallelism does not require that all single yarns be accurately aligned in parallel, and an error of about ± 10 degrees is partially allowed. It Further, it is desirable that each single yarn has a circular cross-sectional shape, but an elliptical shape or an oval shape may also be used. Further, from the viewpoint of ensuring water permeability and resistance to earth pressure, the diameter of the single yarn having the shortest diameter is preferably 1 to 10 mm, more preferably 2 to
A 6 mm one is used. In addition, it is desirable that each single yarn is independent, but if it is partially, even if adjacent single yarns are fused, there is no practical problem.

Further, the raw materials of many filaments used in the present invention may be either natural fibers or synthetic fibers as long as the above structure can be obtained, but in order to obtain the above structure more easily. For this purpose, it is desirable to use synthetic fibers, especially thermoplastic resins. Further, as the thermoplastic resin, polyethylene, polypropylene, polyamide, polyester, a copolymer resin containing these as one component, a blended resin thereof, and the like are preferably used in forming the above structure. More preferably, a water-permeable civil engineering sheet further excellent in bondability (fusion adhesion) is obtained by forming a three-layer laminated structure in which a large number of filaments made of polyester-based resin are sandwiched between polyester long-fiber nonwoven fabrics. Can be provided.

In particular, when the above-mentioned thermoplastic resin is used as a raw material for a large number of filaments used in the present invention, the upper and lower two nonwoven fabrics are formed while the large number of filaments are still in the melt-softened state. By sandwiching and crimping, the thermoplastic resin forming the filament body is melted in a molten state in a state of permeating to a part in the thickness direction of the nonwoven fabric and then fixed. In the water-permeable civil engineering sheet thus obtained, the resin forming the filament is fusion bonded to a part of the non-woven fabric layer, and a large number of filaments are formed by the anchor effect of the non-woven fabric layer and the resin constituting the filament. The bond between and non-woven fabric becomes strong.

The yarn used in the present invention has a core-sheath structure fiber having a low melting point polymer as a core component and a polymer having a higher melting point as a sheath component, that is, the core has a viscosity when melted. By using a resin that is high and difficult to deform, it imparts a resistance to external force, the sheath has a low viscosity when melted and easily penetrates into a part of the non-woven fabric layer, for example, a resin having good adhesiveness to the non-woven fabric, and more preferably By using the same kind of resin as the non-woven fabric, it is possible to provide a water-permeable civil engineering sheet in which the bonding of the many non-woven fabrics with the non-woven fabric is strong and the cross-sectional shape of the many non-woven fabrics is close to a circle.

The water-permeable civil engineering sheet according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic sectional view showing an example of the water-permeable civil engineering sheet of the present invention. Between the two non-woven fabrics 1 and 2,
A large number of filaments 3 are arranged substantially in parallel and fused as a three-layer laminated structure. The water-permeable civil engineering sheet of the present invention,
It is preferably used as a drainage sheet for civil engineering because water can be positively passed in one direction of the filament arrangement direction in the in-plane direction. That is, the purpose of the civil engineering drainage sheet is to drain excess water in the soil into the air, and the water-permeable civil engineering sheet according to the present invention causes excess water to pass through the nonwoven fabric layer (in the Z direction) due to the pressure in the soil. ) Capture,
Without returning the excess water taken in to the soil from the vertical direction (Y direction) of the filamentous arrangement of the many filaments in the sheet surface, in the filamentous arrangement direction (X direction) of the many filaments in the sheet surface. Drainage is achieved by positively flowing it. In order to achieve the above characteristics, 3 of the water-permeable civil engineering sheet is used.
It is preferable that the easiness of water flow in the direction is different, that is, the water permeability in the Z direction measured according to JIS-A-1218 and the measurement with the apparatus of FIG.
The permeability coefficient in the X and Y directions calculated by the calculation formula of 1218 is (permeability coefficient in the X direction)> (permeability coefficient in the Z direction)
> (Water permeability in the Y direction) is preferable. In particular,
From the relationship with the pressure in the soil, the hydraulic conductivity in the Z direction is 10 ^-2.
Preferably ~10 ⁰ cm / sec, X direction 10 ^-1 cm / sec or more, Y directions preferably have a permeability of less 10 ^-2 cm / sec.

[0014]

EXAMPLES The present invention will be described in more detail below with reference to examples.

Example 1 A polyethylene resin, which is a raw material for many filaments, has a diameter of 5 mm.
Melt extruded from a die with 8 mm pitch arranged side by side, and while still in a molten state, denier of single yarn is 3d, weight per unit is 150 g / m ² , thickness 0.46 mm, JI
Aeration rate 4 measured by SL-1096 Frazier method
5 cc / cm ² / sec polyester long-fiber non-woven fabric Thermal sandwich type non-woven fabric, clearance 4 mm 2
The water-permeable civil engineering sheet of the present invention was obtained through a chill roll of a book.

The obtained water-permeable civil engineering sheet has the cross-sectional shape shown in FIG. 1, and a large number of parallel non-woven fabrics having an elliptical cross-sectional shape with a maximum diameter of about 6.5 mm. It had a structure in which lined filaments were sandwiched.

The water permeability of the obtained water-permeable civil engineering sheet was measured. The water permeability coefficient in the thickness direction of the sheet is JIS-A-1.
It measured by 218 and obtained 1.9 * 10 ^<-2 > cm / sec.
On the other hand, the water permeability in the in-plane direction of the sheet was calculated according to the formula of JIS-A-1218 by conducting an experiment with the apparatus shown in FIG. The hydraulic conductivity in the direction of many filaments in the seat surface is
The water permeability in the vertical direction was 9.1 × 10 ^-1 cm / sec, and the number of filaments in the sheet surface was 5.6 × 10 ^-3 cm / sec. The sheet was a water-permeable civil engineering sheet suitable for a civil engineering drainage material capable of positively permeating water in the direction of many filaments in the sheet surface.

[0018]

EFFECTS OF THE INVENTION The present invention having the above-mentioned structure has the following excellent effects.

A) The water-permeable civil engineering sheet according to the present invention is preferably used as a drainage sheet for civil engineering because it can positively permeate water in one direction in the in-plane direction. That is, the drainage sheet for civil engineering is mainly for draining surplus water in the soil into the air, and the water-permeable civil engineering sheet according to the present invention, the surplus water in the sheet that has passed through the nonwoven fabric is within the sheet surface. Positively flowing in the yarn direction of a large number of yarn bodies, without flowing excess water back into the soil by flowing in a direction perpendicular to the large number of yarns in the sheet surface, It serves the purpose.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the water-permeable civil engineering sheet of the present invention.

FIG. 2 is a schematic diagram of an apparatus for measuring the in-plane water permeability coefficient of a water-permeable civil engineering sheet.

[Explanation of symbols]

 1: Non-woven fabric 2: Non-woven fabric 3: Many parallel filaments 4: Water supply port 5: Water supply layer 6: Head difference (Δh) 7: Permeable civil engineering sheet 8: Overlaying pressure (q) 9: Drainage layer 10: Overflow mouth

Claims (10)

[Claims] 1. A water-permeable civil engineering sheet characterized in that a large number of filaments are fused between two non-woven fabrics to form a three-layer laminated structure. 2. The water-permeable civil engineering sheet according to claim 1, wherein the cross-sectional shape of the single filament yarn is circular, elliptical or oval. 3. The filament has a diameter of 1 to 1 at the shortest diameter.
The water-permeable civil engineering sheet according to claim 1, which has a thickness of 0 mm. 4. The resin constituting the filamentous material is polyethylene,
The water-permeable civil engineering sheet according to claim 1, which is at least one selected from polypropylene, polyamide, polyester, or a copolymer or blend containing these as one component. 5. The water-permeable civil engineering sheet according to claim 1, wherein the filamentous material contains a core-sheath structure fiber having a low melting point polymer as a core component and a higher melting point polymer as a sheath component. 6. The water-permeable civil engineering sheet according to claim 1, wherein the non-woven fabric is a polyester long-fiber non-woven fabric. 7. The water-permeable civil engineering sheet according to claim 1, wherein the non-woven fabric is made of the same kind of polymer as the resin constituting the filamentous body. 8. The water-permeable civil engineering sheet according to claim 1, wherein the longitudinal filament permeability coefficient of the in-plane filamentous material of the water-permeable civil engineering sheet is larger than the water permeability coefficient in the thickness direction. 9. A water-permeable civil engineering sheet having a thickness of 10 ^{-2 in the} thickness direction.
10 ⁰ cm / sec order permeability civil sheet according to claim 1, wherein those having a hydraulic conductivity of. 10. The water-permeable civil engineering sheet according to claim 1, wherein the water-permeable civil engineering sheet is used as a slope protection drainage material for civil engineering or a vertical drainage material for civil engineering.