JPH08121094A - Sheet for discharging spring water in tunnel - Google Patents

Abstract

PURPOSE: To maintain positively a drainage function by installing a water permeable layer made of resin or rubber on a single surface of a needle punched non-woven cloth with a specified weight and thickness and specifying an elongation and a coefficient of permeability after the application of a specific fixed load. CONSTITUTION: A resin or rubber-made water conducting layer 3 is installed to a single surface of a needle punched non-woven cloth whose weight exceeds 300g/m<2> and, what is more, whose thickness exceeds 3mm. On one hand, preferably, a hydrophobic resin or rubber-made hydrophobic layer be installed on the other surface. In this case, the following properties are required as a drainage sheet 1: The elongation is 2% and below and the coefficient of permeability in the sheet face direction is 1.0×10-<1> cm/sec and over after the application of a fixed load of 1.5kg force/5cm width for 7 days. The water permeable layer 3 is laid out so that it may face with the subsoil side of an excavated tunnel. Then, spring water from the underground is discharged from the inside of the non-woven cloth outside the tunnel by way of the water permeable layer 3. This construction makes it possible to discharge efficiently spring water from the underground outside the tunnel and cast concrete to a satisfactory extent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet which has a small elongation under a constant load and is used for discharging spring water in a tunnel, especially in a cold region.

[0002]

2. Description of the Related Art In recent years, the development of non-woven fabrics has been remarkable and has been used for a wide range of applications such as clothing, packaging, sanitary materials, agriculture, civil engineering, etc., depending on the characteristics of the raw material fibers, manufacturing method and the like. . Among them, non-woven fabrics are used for civil engineering applications, especially for tunnel drainage sheets. In other words, when digging a tunnel, if water springs out of the soil, the presence of this water will prevent the concrete from being painted even if you try to place it in the tunnel. Since problems such as cracking occur, it is necessary to drain water efficiently. As a method of efficiently draining water, there is a method of laying a non-woven fabric in contact with the soil side of a dug tunnel and laying a water-impermeable sheet made of an ethylene-vinyl acetate copolymer or the like on the concrete side. According to this method, the water that springs from the soil passes through the nonwoven fabric and is discharged to the outside of the tunnel, while the impermeable sheet is placed on the concrete side. It does not leak to the application side. That is, since the non-woven fabric functions as a drainage layer and the water-impermeable sheet functions as a water-impermeable layer, concrete can be efficiently placed.

For example, Japanese Utility Model Publication No. 51-37844 discloses a water-permeable sheet for civil engineering work in which a nonwoven fabric (water-permeable layer) and a water-impermeable layer are integrated.

However, when used in cold regions, it is necessary to lay a heat insulating layer such as hard urethane foam on the side of the impermeable sheet in order to prevent freezing of permeated water from the ground. In this method, the nonwoven fabric is loaded by the heat insulation layer for a long period of time, so the nonwoven fabric stretches or sags due to it, drainage performance deteriorates, and the concrete side becomes wavy due to slack and concrete pouring. However, there is a problem in that

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above problems and to provide a sheet for discharge of seepage water in a tunnel which has a small elongation under a constant load. further,
It is an object of the present invention to provide a sheet for discharging spring water in a tunnel, which does not require a water-impermeable sheet that has been conventionally used and has a small elongation under a constant load.

[0006]

[Means for Solving the Problems] That is, the present invention is a sheet comprising a needle punched nonwoven fabric having a basis weight of 300 g / m ² or more and a thickness of 3 mm or more provided with a water-conducting layer made of resin or rubber on one side. 1.5kg weight / 5
The extension ratio after applying a constant load of cm width for 7 days is 2% or less,
And the water permeability in the sheet surface direction is 1.0 × 10 ^-1 cm / s
The gist is a sheet for discharging spring water in a tunnel, which is characterized in that it is ec or more.

Further, the present invention has a basis weight of 300 g / m ^2.
A sheet in which a water-permeable layer made of resin or rubber is provided on one surface of a needle-punched nonwoven fabric having a thickness of 3 mm or more, and a water-impervious layer made of hydrophobic resin or rubber is provided on the other surface. 5kg weight / 5cm width constant load 7
The gist is a sheet for discharging spring water in a tunnel, which has an elongation rate of 2% or less after application for a day and has a water permeability coefficient of 1.0 × 10 ^-1 cm / sec or more in a sheet surface direction. It is a thing.

Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a spring water discharge sheet of the present invention. In FIG. 1, the spring water discharge sheet 1 is a sheet in which a water guide layer 3 made of resin or rubber is provided on one surface of a needle punched nonwoven fabric 2 having a basis weight of 300 g / m ² or more and a thickness of 3 mm or more, and the sheet The water permeability coefficient in the surface direction is 1.0 × 10 ⁻¹ cm / sec or more.

FIG. 2 is a sectional view showing another example of the spring water discharge sheet of the present invention. In FIG. 2, the spring water discharge sheet 1 has a basis weight of 300 g / m ² or more and a thickness of 3 mm.
A sheet in which the water guide layer 3 made of resin or rubber is provided on one surface of the needle punched nonwoven fabric 2 described above, and the water shield layer 4 made of hydrophobic resin or rubber is provided on the other surface,
The extension rate after applying a constant load of 1.5 kg weight / 5 cm width for 7 days is 2% or less, and the water permeability coefficient in the sheet surface direction is 1.0 ×.
It is 10 ^-1 cm / sec or more.

The constituent fibers of the non-woven fabric used in the present invention include natural fibers and thermoplastic synthetic resin fibers. Examples of the natural fiber include cotton, hemp, and wool.
Examples of the thermoplastic synthetic resin fibers include polyester polymers such as polyethylene terephthalate and polybutylene terephthalate, or acid components such as phthalic acid, isophthalic acid, glutaric acid, adipic acid, and diethylene glycol, propylene glycol, 2,2- Screw (4
-Hydroxyethoxyphenyl) propane, copolymer polyesters copolymerized with diol components such as bisphenol A, polyolefin polymers such as polyethylene and polypropylene, polyamide polymers such as nylon 6 and nylon 66, vinylon, etc. Representative polyvinyl alcohol-based polymers are used, and fibers made of these polymers alone, or bonded type composite fibers or core-sheath type composite fibers in which two or more different polymers are combined can be used. Can be used.

The single yarn fineness of the constituent fibers of the nonwoven fabric used in the present invention is preferably 2 to 10 denier, more preferably 3
~ 7 denier. If the denier is less than 2 denier, the fibers are likely to be broken when subjected to needle punching, and mechanical properties such as tensile strength of the obtained nonwoven fabric are deteriorated, which is not preferable. Further, if it is larger than 10 denier, the entanglement of fibers is not sufficiently formed, and the mechanical properties such as tensile strength of the obtained nonwoven fabric are deteriorated, which is not preferable.

The form of the constituent fibers of the nonwoven fabric used in the present invention may be either short fibers or long fibers, but for the purpose of the present invention, long fibers are preferable, and thermoplastic synthetic long fibers are particularly preferable.

When short fibers are used, it is preferable that a web is formed by using a web forming means such as a card or a random webber, and the obtained web is subjected to needle punching to obtain a nonwoven fabric.

When long fibers are used, a non-woven fabric is formed by forming a web by a so-called spunbond method and subjecting the obtained web to needle punching. This needle punching process may be a continuous process or a separate process.

The conditions for the needle punching treatment are not particularly limited, but a punch density of 50 to 150 pieces / cm ² is preferable from the viewpoint of improving the mechanical properties of the nonwoven fabric and the entanglement of fibers. When the punch density is less than 50 pieces / cm ² , the entanglement of fibers is insufficient, the mechanical properties such as tensile strength of the nonwoven fabric are not improved, and the nonwoven fabric is very weak and fluffy.
On the other hand, if the punch density exceeds 150 pieces / cm ² , the fibers are sufficiently entangled, but the fibers are partially cut, so that the nonwoven fabric is inferior in mechanical properties such as tensile strength. Such a nonwoven fabric has a large elongation rate after applying a constant load, which is not preferable in the present invention.

The basis weight and thickness of the non-woven fabric used in the present invention must be 300 g / m ² or more and 3 mm or more, respectively. Unit weight and thickness are 300g / m
^If it is less than ^{2 and} less than 3 mm, the strength of the sheet itself made of this non-woven fabric is low, and not only it is easily stretched, but also sufficient drainage performance cannot be obtained during use, which is not preferable.

A basis weight of 300 g / m ² or more and a thickness of 3 m
When it is less than m, the density of the non-woven fabric is increased and the drainage performance during use is deteriorated, which is not preferable. On the other hand, the thickness is 3m
When it is m or more and the basis weight is less than 300 g / m ² , the strength of the non-woven fabric is low, and the strength of the sheet itself using the non-woven fabric is low, which tends to cause elongation, which is not preferable. Also,
The fluff is increased on both sides of the non-woven fabric, so that when the water-conducting layer made of a resin or the like is provided, there are many troubles such as winding of the sheet around a roll, which is not preferable.

The upper limits of the areal weight and the thickness are not particularly limited, but it is preferable to set them to about 1000 g / m ² and about 10 mm, respectively, from the viewpoint of the purpose and workability of the present invention.

In the present invention, a water-conducting layer made of resin or rubber is provided on one side of the non-woven fabric for the purpose of reducing the elongation rate after applying a constant load and guiding the spring water in the tunnel to the drainage layer (non-woven fabric layer). Set up.

The resin or rubber used for the water guiding layer is
Thermosetting resin such as acrylic ester, vinyl acetate, vinyl chloride, urea / formaldehyde, melamine / formaldehyde, carboxylic acid / formaldehyde, carboxylic acid resin elastomer, unsaturated polyester, polyester elastomer, furan resin, epoxy resin, isocyanate resin, etc. Examples of the resin include natural resins, natural rubber, chlorinated rubber, nitrile rubber, silicone rubber, and other rubbers, which may be selected according to the purpose.

Examples of the method for providing the water-conducting layer on one side of the non-woven fabric include a method of heating and melting a resin and extruding it from a die to coat the non-woven fabric, and a method of foaming an emulsion of the resin to foam-coat the non-woven fabric. To be At this time, if the resin or rubber is formed into a film on the surface of the non-woven fabric to form a water-impermeable layer, the water flowing out from the soil cannot be satisfactorily guided to the drainage layer (non-woven fabric layer), which is not preferable. Therefore, in order to prevent this, for example, in the foam coating, open cells are provided, and in the melt coating, a portion having no resin is provided.

Further, in the present invention, it is desirable to provide a water blocking layer made of a hydrophobic resin or rubber on the other surface of the non-woven fabric.

As the hydrophobic resin or rubber used for the water blocking layer, thermoplastic resins such as acrylic acid ester, vinyl acetate and vinyl chloride, urea / formaldehyde, melamine / formaldehyde, carboxylic acid / formaldehyde, carboxylic acid resin elastomer, unsaturated Thermosetting resins such as polyester, polyester elastomer, furan resin, epoxy resin, and isocyanate resin, and rubbers such as natural rubber, chlorinated rubber, nitrile rubber, and silicone rubber can be used, and may be selected according to the purpose.

As a method of providing a water-impervious layer on the other surface of the non-woven fabric, coating, topping, pouring, coating,
Coating, spraying, curing of the synthetic resin layer or pressure bonding (compression bonding) before the reaction is completed, pushing in, or bonding of the resin or rubber sheet etc. by heat lamination, hot melt adhesion, surface fasteners, etc. Therefore, a treatment that matches the properties of the resin or rubber used may be appropriately adopted.

The amount of the resin or rubber used in the present invention is not particularly limited as long as the elongation rate after application of a constant load can be reduced, and may be appropriately selected depending on the type of the resin or rubber. May be 10 to 30% by weight with respect to the weight of the nonwoven fabric.

If the amount of resin or rubber is less than 10% by weight, the elongation rate under constant load does not decrease, which is not preferable. On the other hand, if it exceeds 30% by weight, the elongation rate under a constant load becomes small, but the weight of the sheet increases, which makes it difficult to apply the sheet, and also increases the cost, which is not preferable.

The resin or rubber used in the present invention preferably penetrates from one side of the nonwoven fabric to 1/3 or less of the thickness of the nonwoven fabric. As a result, the non-woven fabric and the resin or rubber layer are satisfactorily joined to each other and the peel resistance of the sheet is improved.

On the other hand, when the resin or rubber penetrates the entire thickness of the nonwoven fabric, the resin or rubber fills the voids between the constituent fibers of the nonwoven fabric, so that the water coming out of the soil is hard to pass through the nonwoven fabric. It is not preferable because the function of the drainage sheet as a drainage layer decreases.

In the present invention, it is necessary that the elongation rate after applying a constant load of 1.5 kg weight / 5 cm width for 7 days is 2% or less. If the extension rate after applying a constant load of 1.5 kg weight / 5 cm width for 7 days exceeds 2%, heat insulation of hard urethane foam etc. is used for the purpose of preventing the freezing of the spring water from the ground when used in cold regions. When a layer is provided, the sheet stretches without being able to bear the weight of the heat retaining layer, causing slack, which makes it difficult to place concrete, which is not preferable.

Further, the water permeability in the sheet surface direction (direction along the sheet surface) is preferably 1.0 × 10 ^-1 cm / sec or more. Permeability coefficient in the sheet surface direction is 1.0
If it is less than × 10 ^-1 cm / sec, the drainage performance is deteriorated and it is difficult to use as a sheet for discharging spring water in a tunnel, which is not preferable.

[0031]

The embodiment of the seat of the present invention for discharging the spring water in the tunnel will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing an example in which the spring water discharge sheet of the present invention is actually used for discharging spring water in a tunnel in a cold region. When you dig a tunnel, water springs out from the ground. In FIG. 3, when laid so as to be in contact with the soil side of the tunnel dug on the water-conducting layer 3 side of the present invention, the water spouting from the soil is efficiently guided to the water-conducting layer 3 and the nonwoven fabric 2
It enters inside and is discharged through the inside of the nonwoven fabric 2 to the outside of the tunnel.

At this time, a water impermeable sheet is provided on the concrete side so that the water flowing out of the tunnel passing through the inside of the nonwoven fabric 2 does not leak to the concrete side, or the other surface of the sheet for discharging the water flowing out. Since the impermeable layer 4 is provided in the tunnel, the spring water in the tunnel does not leak to the concrete side and is discharged well through the inside of the nonwoven fabric 2.

When used in a cold region, a heat insulating layer 5 made of hard urethane foam or the like is laid on the water shield layer 4 side for the purpose of preventing freezing of the spring water from the natural ground. In order to provide the heat retaining layer 5, the load of the heat retaining layer 5 is applied to the nonwoven fabric 2 for a long period of time. However, in the sheet 1 for discharge of spring water of the present invention, the nonwoven fabric 2 is provided with the water-conducting layer 3 made of resin or rubber, that is, the resin or rubber penetrates the nonwoven fabric from one side to 1/3 or less of the thickness of the nonwoven fabric. However, the resin or rubber is filled in a part of the voids between the constituent fibers of the non-woven fabric, and the characteristics of the resin or rubber used in the present invention also contribute to the sheet of the present invention after applying a constant load. Since the elongation rate is small, the nonwoven fabric 2 does not stretch and sag. Therefore, the spring water discharge sheet 1 of the present invention is used even in cold regions.
Can withstand the weight of the heat retaining layer 5. Further, the water permeability coefficient in the sheet surface direction (direction along the sheet surface) is 1.0.
Since it is × 10 ^-1 cm / sec or more, the water spouting from the soil can be efficiently discharged out of the tunnel, and the concrete can be satisfactorily placed.

[0034]

EXAMPLES Next, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

In the examples, each characteristic value was measured by the following method. Single yarn fineness (denier): The single yarn fineness (denier) of the long fibers constituting the nonwoven fabric was determined by the following method. That is,
An enlarged surface photograph of the nonwoven fabric was taken using an electron microscope to measure the diameter of single yarn in the photograph, and this value was divided by the enlargement ratio and corrected by the fiber density to obtain the single yarn fineness (denier).

Unit weight (g / m ² ): A total of 10 sample pieces measuring 50 cm in length and 50 cm in width were prepared from the sample in the standard state to reach the equilibrium water content, and then the weight (g) of each sample piece was weighed. The average value of the obtained values was converted per unit area (m ² ) to obtain a basis weight (g / m ² ).

Elongation rate (%): Measured according to the method described in JIS-L-1096A. That is, the sample length is 20
cm, sample width of 5 cm, 10 points in total were prepared, and a constant speed elongation type tensile tester (Tensilon UTM-4-1 manufactured by Toyo Baldwin Co., Ltd.) was used for each sample piece in the warp direction of the nonwoven fabric.
-100), a load of 1.5 kg weight / 5 cm width was grasped and applied at a 10 cm interval for 7 days, and the average value of the obtained elongation rates (%) was determined.

Permeability coefficient in the sheet surface direction (cm / se
c): Measured according to the method described in JIS-A-1218. The number of measurements was 3 and the average value was used as the water permeability coefficient in the sheet surface direction.

Example 1 First, a spunbonded nonwoven fabric made of polyethylene terephthalate polymer filaments was prepared. That is, the polymer chip is melted using an extruder type melt extruder, melt-spun through a spinneret, the spun yarn is cooled, and then traction and thinning are performed using an air sucker arranged below the spinneret. After opening, open using a corona discharge device,
Collecting and depositing on the screen mesh type moving collecting surface,
A web having a single yarn fineness of 3.8 denier and a basis weight of 350 g / m ^{2 was used} , and the obtained web had a punch density of 90 pieces / cm ^2.
Needle punched under conditions of 3.2 mm thickness
A spunbonded non-woven fabric was obtained. Then, one side of the non-woven fabric was coated with styrene-butadiene rubber at a basis weight of 50 g / m ² by a foam coating method, heat-treated under a condition of a temperature of 170 ° C. to provide a water guiding layer, and the sheet of the present invention of Example 1 was obtained. Obtained.

Example 2 In the same manner as in Example 1 except that the single yarn fineness of the spunbonded nonwoven fabric was 3.0 denier and the basis weight was 305 g / m ² .
A spunbonded nonwoven fabric having a thickness of 3.1 mm was obtained. Then, a sheet of Example 2 was obtained in the same manner as in Example 1 except that the grammage of the rubber was 70 g / m ² and the styrene-butadiene rubber was coated to provide a water guide layer.

Example 3 A sheet of Example 3 was obtained in the same manner as in Example 2 except that a styrene-butadiene rubber was coated to provide a water guide layer with a rubber basis weight of 40 g / m ² .

Example 4 First, a spunbonded nonwoven fabric made of polyethylene terephthalate polymer filaments was prepared. That is, the polymer chips are melted using an extruder-type melt extruder, melt-spun through a spinneret, the spun yarn is cooled, and then traction / fine squeezing is performed using an air sacker arranged below the spinneret. After opening, open using a corona discharge device,
Screen mesh type Collects and deposits on the moving collecting surface,
A web having a single yarn fineness of 3.8 denier and a basis weight of 350 g / m ^{2 was used} , and the obtained web had a punch density of 90 pieces / cm ^2.
Needle punched under conditions of 3.2 mm thickness
A spunbonded non-woven fabric was obtained. Then, on one side of the non-woven fabric, to have open cells by the foam coating method,
Styrene-butadiene rubber was coated at a basis weight of 50 g / m ² and heat-treated under the condition of a temperature of 170 ° C. to provide a water guiding layer. Then, on the other surface, an ethylene-vinyl acetate copolymer was processed by a usual slit T-type extrusion laminating method to provide a water-impervious layer, and a sheet of the present invention of Example 4 was obtained.

Comparative Example 1 In the same manner as in Example 1, the single yarn fineness of the spunbonded nonwoven fabric was 3.8 denier, the basis weight was 350 g / m ² , the punch density was 90 pieces / cm ² , and the thickness was 3.2 mm. A spunbonded non-woven fabric was obtained.

Comparative Example 2 Spunbonded nonwoven fabric has a single yarn fineness of 4 denier and a basis weight of 3
A spunbonded non-woven fabric having a thickness of 3.5 mm was obtained in the same manner as in Example 1 except that the density was 50 g / m ² and the punch density was 100 pieces / cm ² . Then, the basis weight of the rubber is 10 g / m
^{As 2} , the sheet of Comparative Example 2 was obtained in the same manner as in Example 1 except that styrene-butadiene rubber was coated.

Comparative Example 3 The thickness of the spunbonded nonwoven fabric was 3 in the same manner as in Example 2 except that the single yarn fineness was 3.5 denier, the basis weight was 350 g / m ² , and the punch density was 80 pieces / cm ^2. A 0.2 mm spunbonded nonwoven fabric was obtained. Then, one side of the non-woven fabric obtained above was coated with an acrylic resin by an impregnation method in a basis weight of 100 g /
A sheet of Comparative Example 3 was obtained in the same manner as in Example 1 except that the sheet was attached by m ² .

Comparative Example 4 The thickness of the spunbonded nonwoven fabric was 3 in the same manner as in Example 1 except that the single yarn fineness was 4.0 denier, the basis weight was 200 g / m ² , and the punch density was 65 pieces / cm ^2. A 0.0 mm spunbonded non-woven fabric was obtained. Next, the basis weight of the rubber is 50 g /
A sheet of Comparative Example 4 was obtained in the same manner as in Example 1 except that styrene-butadiene rubber was coated as m ² .

[0047] Comparative Example 5 single fineness of 4.0 denier spunbonded nonwoven, 320 g / m ² basis weight, except that the punch density was 170 / cm ² or in the same manner as in Example 1, a thickness of 2 A 0.0 mm spunbonded non-woven fabric was obtained. Next, weigh 50 g of rubber
/ M ² , the sheet of Comparative Example 5 was obtained in the same manner as in Example 1 except that styrene-butadiene rubber was coated.

Table 1 shows each of the above characteristic values.

[0049]

[Table 1]

The sheets of Examples 1 to 4 have a weight of 1.5 kg /
The elongation is small after applying a load of 5 cm width for 7 days,
The growth was extremely low. Therefore, even if it is actually used as a sheet for discharging spring water in a tunnel in cold regions, it can drain water satisfactorily and efficiently without sagging due to the load of the heat insulation layer, and it does not hinder concrete placement. Concrete can be applied well.

Since the spunbonded nonwoven fabric of Comparative Example 1 was not provided with the water guiding layer, it had a large elongation rate and a large elongation after a load of 1.5 kg weight / 5 cm width was applied for 7 days. Therefore, even if it is actually used as a spring water discharge sheet in a tunnel in a cold region, the load cannot be withstood by the heat insulating layer, causing slack, and concrete pouring cannot be performed well.

The sheet of Comparative Example 2 had a large elongation after a load of 1.5 kg weight / 5 cm width was applied for 7 days because the basis weight of the coated rubber was small and the elongation was large. Therefore, even if it is actually used as a spring water discharge sheet in a tunnel in a cold region, the load cannot be withstood by the heat insulating layer, causing slack, and concrete pouring cannot be performed well.

The sheet of Comparative Example 3 has a weight of 1.5 kg / 5c.
The elongation ratio after applying a load of m width for 7 days was small and the elongation was small. However, the acrylic resin had penetrated the entire thickness of the non-woven fabric, and the voids between the constituent fibers of the non-woven fabric had been filled, so it was actually used as a spring water discharge sheet in tunnels in cold regions. Even
The drainage of the spring water in the tunnel was poor, and it was not a sheet that could be used for discharging the spring water in the tunnel.

The sheet of Comparative Example 4 had a nonwoven fabric weight of 30.
Since it is less than 0 g / m ^2, it does not have sufficient strength,
The elongation rate was large after applying a load of 1.5 kg weight / 5 cm width for 7 days, and the elongation was large. Therefore, even if it is actually used as a spring water discharge sheet in a tunnel in a cold region, slack occurs, and concrete pouring cannot be performed successfully.

The sheet of Comparative Example 5 has a weight of 1.5 kg / 5c.
The elongation rate was small after applying an m-width load for 7 days, and the elongation was small. However, since the thickness of the nonwoven fabric is small, even if it is actually used as a sheet for discharging spring water in a tunnel in cold regions, the drainage of the spring water in the tunnel is poor and it can be used as a sheet for discharging spring water in the tunnel. is not.

[0056]

EFFECTS OF THE INVENTION In a conventional non-woven sheet only subjected to needle punching, it is difficult to keep the elongation rate below 2% after applying the constant load, no matter how the needle punching conditions are set, and the nonwoven fabric is kept warm. It was difficult to withstand the weight of the layer and it was difficult to prevent the slack due to stretching. In contrast,
Since the sheet of the present invention is provided with the water-conducting layer made of resin or rubber, the elongation after applying a constant load of 1.5 kg weight / 5 cm width for 7 days is 2% or less, which is higher than that of the conventional nonwoven fabric. Since the elongation rate under a constant load is small, even if the sheet is used in a cold region and a heat retaining layer is provided, the load is applied by the heat retaining layer but the sheet does not stretch and sag. Further, the sheet of the present invention further provided with a water blocking layer made of a hydrophobic resin or rubber on the other surface has a small elongation rate under constant load, and is used in a cold region, and is provided with a heat insulating layer. However, although the load is applied by the heat retaining layer, the sheet does not stretch and sag, and it does not take time and effort to arrange the water impermeable sheet.

Therefore, the sheet of the present invention has a good drainage function and does not cause any trouble during concrete pouring.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a spring water discharge sheet of the present invention.

FIG. 2 is a cross-sectional view showing another example of the spring water discharge sheet of the present invention.

FIG. 3 is a cross-sectional view showing an example in which the sheet for discharging spring water of the present invention is actually used for discharging spring water in a tunnel in a cold region.

[Explanation of symbols]

 1: Sheet for discharging spring water in a tunnel 2: Nonwoven fabric 3: Water-conducting layer made of resin or rubber 4: Impermeable layer made of hydrophobic resin or rubber 5: Heat insulating layer 6: Concrete

Claims (2)

[Claims] 1. A sheet comprising a needle punched non-woven fabric having a basis weight of 300 g / m ² or more and a thickness of 3 mm or more and a water-conducting layer made of resin or rubber provided on one side of the nonwoven fabric.
The extension rate after applying a constant load of 1.5 kg weight / 5 cm width for 7 days is 2% or less, and the water permeability coefficient in the sheet surface direction is 1.0.
A sheet for discharging spring water in a tunnel, characterized by having a density of × 10 ^-1 cm / sec or more. 2. A water-permeable layer made of resin or rubber is provided on one surface of a needle punched nonwoven fabric having a basis weight of 300 g / m ² or more and a thickness of 3 mm or more, and a water-permeable layer made of hydrophobic resin or rubber on the other surface. A sheet provided with,
The extension rate after applying a constant load of 1.5 kg weight / 5 cm width for 7 days is 2% or less, and the water permeability coefficient in the sheet surface direction is 1.0.
A sheet for discharging spring water in a tunnel, characterized by having a density of × 10 ^-1 cm / sec or more.