JPH08326493A - Waterproof sheet for tunnel and spreading method thereof - Google Patents

Abstract

PURPOSE: To improve the draining capacity of seepage out of a tunnel and the buffering property against the external pressure, by welding a non-woven cloth with heat to a rubber or synthetic resin base sheet provided with a number of protrusions on the surface and laminating it. CONSTITUTION: Protrusions 3 are provided on the surface of a base sheet 1 to withstand external pressure and further, a non-woven buffer material 2 is laminated thereon. The buffer material 2 is pressed by the protrusions. In this case, since the protrusions are independent respectively, the seepage stream is made smooth and drained. When the shape of protrusions is specified and it is deformed by an external force from the surface side, the external force is absorbed and buffered to prevent damage of the sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof sheet for tunnels and a method of spreading the same, and more specifically, a waterproof sheet having improved drainage of water leaching from the natural side and buffering against external pressure. And the method of extension.

[0002]

2. Description of the Related Art In recent years, a NATM method (New Austrian method) has been used as a method of coping with water that seeps out in a tunnel.
A construction method in which a tunneling method) and a water leakage prevention construction method are combined is widely adopted. In this combined construction method, the primary lining is performed on the surface of the excavated tunnel ground by concrete spraying and rock bolting, and a waterproof sheet is stretched on the primary lining surface and a secondary covering is applied on the back surface. It is a construction method that is performed. As the waterproof sheet used here, a sheet base made of rubber or synthetic resin, to which a non-woven fabric cushioning material is heat-welded on the ground side (back side) is widely used.

FIG. 7 is a cross-sectional view of the above waterproof sheet. In the figure, 11 is a sheet base having a thickness of about 1 mm, and a non-woven cloth cushioning material 12 having a thickness of about 3 mm is formed in a strip shape on the back surface. It is heat-welded to form a waterproof sheet. Also known is a waterproof sheet in which a three-dimensional mesh body made of polypropylene or a non-woven fabric is laminated on the surface of the cushioning material 12 of the above-mentioned waterproof sheet. Further, there is also known a waterproof sheet in which a large number of convex projections are simply formed on the back side of the base sheet 11 without using a cushioning material. However, in the waterproof sheet shown in FIG. 7, the cushioning material is easily crushed by the external pressure from the ground side or the surface side of the waterproof sheet, so that the drainability of water leaching from the ground side is deteriorated. Occurs.

On the other hand, the waterproof sheet in which the three-dimensional net body and the non-woven fabric are laminated has a certain degree of improvement in the drainage property, but basically the drainage is caused by the collapse of the three-dimensional net body and the non-woven fabric. The problem of deterioration of the property is not solved, and there are drawbacks such that the cost of the waterproof sheet becomes high and the weight becomes heavy. Further, the waterproof sheet having only the convex protrusions formed on the back surface of the sheet substrate has improved drainage property, but is insufficient in buffering property and sandproofing property, and sand and pebbles from the natural ground side are not removed. It will be flushed as it is. However, sponge-like drainage materials are usually provided at the bottom of both sides of the tunnel, and the water that seeps out from the ground side will be discharged through these drainage materials, but this drainage material will be clogged with sand, etc. There are drawbacks.

[0005]

DISCLOSURE OF THE INVENTION The waterproof sheet and the method for spreading the same according to the present invention are an improvement over the above-mentioned drawbacks of the conventional waterproof sheets. The present invention also provides an improved new waterproof sheet and a method for spreading the same.

[0006]

The first gist of the present invention is as follows.
A waterproof sheet for a tunnel, which is a sheet base made of rubber or synthetic resin having a large number of projections on at least one side, and a nonwoven fabric is laminated on at least one side of the sheet base. The sheet is preferably a hollow protrusion in which the tip of the protrusion is opened, and the open surface of the hollow protrusion is (elliptical) circular, and the nonwoven fabric is heat-melted on the sheet base. It is laminated by wearing.

A second aspect of the present invention relates to a method for spreading a waterproof sheet for a tunnel, which is a sheet made of rubber or synthetic resin having a plurality of projections on at least one side of the tunnel surface. A method for spreading a waterproof sheet, which is a substrate and has a nonwoven fabric laminated on at least one surface of the sheet substrate, wherein the major axis of the elliptical open surface of the hollow projection is in the transverse direction of the tunnel. A method of spreading a waterproof sheet for tunnels mounted so that the directions thereof are parallel to each other, and as still another method, a sheet made of rubber or synthetic resin having a non-woven fabric and a large number of protrusions on at least one surface thereof. The present invention relates to a method for spreading a waterproof sheet for a tunnel in which a non-woven fabric is separately provided, a non-woven fabric is first attached to the natural ground side, and then a sheet substrate is attached on the non-woven fabric.

[0008]

Since the present invention has the above-mentioned structure, a large number of (hollow) projections formed on the sheet substrate oppose the external pressure from the ground side or the front side, and the projections absorb the nonwoven fabric or the like. Although pressing the body, the projections are independent of each other, so that the water is always discharged without blocking the flow path of the exuded water. Then, the shape of the projection is defined, and the external force is absorbed and buffered by the deformation by the external force from the natural side or the front side, thereby preventing damage to the waterproof sheet.

The material of the sheet base is rubber or synthetic resin,
For example, it is made of ethylene copolymer bitumen (ECB), polyvinyl chloride (PBC), preferably ethylene vinyl acetate copolymer (EVA), and the non-woven fabric cushioning material is preferably polyester long-fiber non-woven fabric. Lamination of both layers is preferably performed by heat welding or hot air. Preferably, the sheet base is provided with protrusions on both sides, and a nonwoven fabric is laminated on one side or both sides of the sheet, which makes it possible to significantly improve cushioning against external pressure. The seat was obtained.

When the waterproof sheet is spread on the tunnel surface, it is attached so that the major axis direction of the elliptical open surface of the hollow protrusion is parallel to the tunnel crossing direction. As a method of spreading, the non-woven fabric and the sheet base made of rubber or synthetic resin having a large number of protrusions on at least one surface are initially separated, and the non-woven fabric is first attached to the ground side, and then the seam is attached. The same effect can be obtained even by a spreading method in which the substrate is attached onto the nonwoven fabric.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The waterproof sheet of the present invention will be described in more detail below with reference to the drawings. FIG. 1 is a partially cutaway plan view on the front side showing a first example of the waterproof sheet according to the present invention, and FIG. 2 is AA of FIG.
3 is a sectional view taken along line BB. 4 is an enlarged view in the vicinity of the hollow protrusion in FIG. 2, and FIG. 5 is an enlarged view in the vicinity of the hollow protrusion in FIG. In the figure, 1 is an EVA sheet base having a thickness of 1 mm, and 2 is a polyester continuous fiber non-woven fabric cushioning material having a thickness of 3 mm. Then, - on the back side bets substrate 1 are a number of hollow projections 3 are formed, the hollow protrusions 3 are overall shape forms the oval, are arranged in rows like, distance L ₁ of the right and left The vertical distance L ₂ was 5 mm, and the vertical distance L ₂ was 2 mm. Of course, the hollow protrusion 3 may have a circular shape.

As far as the hollow projection 3 is concerned, it has an elliptical shape with a major axis length L ₀₁ of 8 mm and a minor axis length L ₀₂ of 5 mm. A recess 4 is formed. And this hollow protrusion 3
Has a trapezoidal side projection with an elevation angle of about 50 degrees on the major axis and an elevation angle of about 70 degrees on the minor axis, and its cross section has a height H of 2 mm.
The tip has a substantially triangular shape with a width W ₁ of about 0.2 to 0.5 mm. In this example, the projection 3 is formed only on the front surface side of the sheet substrate 1, but it goes without saying that the same projection 3 may be formed on the back surface. In this example, the sheet base 1 has a hardness of 98 degrees (JIS-A) and a tensile strength of 160 kgf.
/ Cm ² (JISK6773), elongation 600% (same),
The tear strength was 50 kgf / cm ² (JIS6301).

The buffer material 2 has a longitudinal tensile strength of 20 k.
gf / 5cm, transverse tensile strength is 5kgf / 5cm ²
(JISL1096), elongation is 20% in the longitudinal direction, 50% in the transverse direction (JISL1096), tear strength is 24 kgf.
/ Cm ² (JISL1096).

FIG. 6 is a sectional view of the same portion as FIG. 2 showing a second example of the waterproof sheet of the present invention. In this example, the projection 3 has no hollow portion and is entirely solid. It is needless to say that the projections 3 may be formed on both front and back surfaces of the sheet substrate 1 as in the previous example, and in some cases, the hollow projections 3 are formed on one surface and the solid projections are formed on the other surface. 3 may be formed.

Various tests will be described below using the waterproof sheet of the first embodiment. (Water passage test) The water passage test was conducted in accordance with "Survey and Research Report on Mountain Tunnel Prevention and Drainage Works (Part 3)" of Japan Tunnel Technical Association.

A. Test apparatus a. Primary lining surface model: Crushed stone was solidified with an adhesive, and a concrete surface was created assuming a concrete surface with a crushed stone protruding height of 3 to 7 mm and a crushed stone protruding portion diameter of 6 to 15 mm. b. Concrete pouring pressure model: The pouring pressure was assumed by uniformly applying pressure to the sheet with an air bag. c. Head pressure: The head pressure was adjusted by tap water and pump pressure. B. EUT: (Drainage effective sheet width 500 mm) a. The product of the present invention: the sheet substrate has a width of 530 mm and a length of 600
The sheet is made of EVA and has a thickness of 1 mm and a thickness of 1 mm. And
The hollow protrusions formed on the sheet substrate were hollow elliptical protrusions having a height of 2 mm, a major axis length of 8 mm, and a minor axis length of 5 mm, and the number was 108/100 cm ² . The cushioning material is a polyester long-fiber nonwoven fabric cushioning material having a thickness of 3 mm. b. Conventional product: In the above-described product of the present invention, a sheet having no hollow protrusion was used as a conventional product. C. So the pressure of the bag 0.3 kgf / cm ² increments is increased, - the air in the state of the water injection pressure 0 kgf / cm ^2: Test methods
At each pressure, it was left for 30 seconds after the start of drainage, and then the water flow rate for 1 minute was measured. D. The results are shown in Table 1.

[0017]

[Table 1]

From Table 1, in the case of the conventional product, the water flow rate becomes almost zero when the external pressure increases, whereas the product of the present invention differs from the conventional product in spite of the increase in the external pressure. It was found that the water flow rate was almost unchanged.

Secondary lining concrete in the NATM method
The back of the sheet is restrained by the spraying concrete. Therefore, when shrinkage strain due to temperature or drying is bound in the secondary lining concrete, cracks may occur in the secondary lining concrete. As a preventive measure, it is desired to separate the two concrete from each other. In the waterproof sheet of the present invention, the hollow projection is compressed and deformed in accordance with the shrinkage strain of the concrete, and not only the edge is cut in a plane but also the edge is cut three-dimensionally.

Here, the amount of compression of the hollow protrusions will be analyzed. (Amount of compression of hollow protrusion) a. Edge cutting effect by FEM (finite element method) analysis: (Analysis conditions) a. Sheet material: EVA b. Sheet Young's modulus: 500 kgf / cm ² c. Working surface pressure: 0.3, 0.5, 1.0, 2.0 kgf
/ Cm ² d. Friction coefficient: 0.2 (μ between projection tip and contact concrete) e. Projection shape: shape of the above embodiment b. Analysis results: as shown in Table 2.

[0021]

[Table 2]

From Table 2, the concrete pouring pressure range (0.3
~0.6kgf / cm ²⁾ amount of compression of the projections in the relatively small, the drainage performance is demonstrated to be retained. on the other hand,
In the concrete crack region (30 kgf / cm ² or more), the projections are expected to undergo large compressive deformation, which shows that a remarkable isolation effect can be expected.

[0023]

INDUSTRIAL APPLICABILITY The present invention provides a waterproof sheet having improved drainage performance by leaching in a tunnel and improved cushioning property against external pressure, and its industrial value is extremely high.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view on the front side of a first embodiment of a waterproof sheet according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is an enlarged view of the vicinity of the protrusion in FIG.

5 is an enlarged view of the vicinity of the protrusion in FIG.

FIG. 6 is a sectional view of a portion similar to FIG. 2 of the second embodiment of the waterproof sheet of the present invention.

FIG. 7 is a cross-sectional view of a conventional waterproof sheet.

[Explanation of symbols] 1, 11 ... Sheet base, 2, 12 ... Non-woven cushioning material, 3 ... Projection, 4 ... Recessed portion.

Claims (6)

[Claims] 1. A sheet base made of rubber or synthetic resin having a large number of projections on at least one surface thereof.
A waterproof sheet for a tunnel, wherein a nonwoven fabric is laminated on at least one surface of the base body. 2. The waterproof sheet for a tunnel according to claim 1, wherein the tip of the protrusion is a hollow protrusion which is open. 3. The waterproof sheet for a tunnel according to claim 2, wherein the open surface of the hollow protrusion has an elliptical shape. 4. The waterproof sheet for a tunnel according to claim 1, wherein a nonwoven fabric is laminated on the sheet substrate by heat fusion. 5. A sheet base made of rubber or synthetic resin having a plurality of projections on at least one side of a tunnel surface, wherein a nonwoven fabric is laminated on at least one side of the sheet base. A method for extending a waterproof sheet for a tunnel, wherein the waterproof sheet for a tunnel is attached so that the major axis direction of the elliptical open surface of the hollow protrusion is parallel to the transverse direction of the tunnel. Method. 6. A non-woven fabric and a rubber or synthetic resin sheet base having a large number of projections on at least one surface are separate, and the non-woven fabric is first attached to the ground side, and then the sheet. A method for spreading a waterproof sheet for a tunnel, characterized in that a substrate is mounted on the non-woven fabric.