JP2018199982A - Waterproof sheet for tunnel - Google Patents

Abstract

To provide a waterproof sheet which can prevent leakage by bringing it into close contact with secondary lining concrete in a tunnel and is inexpensive.SOLUTION: A waterproof sheet 10 is stretched between primary lining concrete 3 of a tunnel 1 and secondary lining concrete 4. The waterproof sheet 10 has a concrete bonding layer 20 laminated on a surface of the second lining concrete 4 side of a waterproof layer 11. The concrete bonding layer 20 is composed of, for example, a mesh-like body 20x and has an embedded portion composed of a mesh member 21 and a filled space portion composed of a mesh 22, the embedded portion is embedded in the secondary lining concrete 4, and the secondary lining concrete 4 is filled in the filled space portion.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a waterproof sheet in a tunnel, and more particularly to a waterproof sheet used for tunnel construction by a NATM (New Austrian Tunneling Method) method or the like.

In tunnel construction by the NATM method, after the primary lining concrete is sprayed on the excavated ground, a waterproof sheet is attached to the inner peripheral surface using a nail or the like. The waterproof sheet is obtained by, for example, laminating a nonwoven fabric layer on one side of the EVA sheet layer, and is installed so that the nonwoven fabric layer faces the primary lining concrete. Thereafter, secondary lining concrete is placed on the inner peripheral side of the waterproof sheet. According to this tunnel, the EVA sheet layer of the waterproof sheet prevents spring water from the natural ground from flowing into the secondary lining concrete side. Spring water is drained through the nonwoven fabric layer of the waterproof sheet.
Further, since the primary lining concrete and the secondary lining concrete are cut off by the waterproof sheet, it is said that the secondary lining concrete is difficult to crack.

  On the other hand, since the construction of the tunnel is a work in a narrow space, it often occurs that the reinforcing steel bars or the like that are being built come into contact with the waterproof sheet and a hole is formed in the waterproof sheet. If this hole can be found in advance, it can be repaired. However, if the hole is small in a dim environment, it may be overlooked. Then, spring water enters the gap at the joint interface between the waterproof sheet and the secondary lining concrete from the hole of the waterproof sheet. Furthermore, if there is a crack in the secondary lining concrete, the spring water may leak into the tunnel along the crack.

  In Patent Document 1, in order to prevent such water leakage, a special blended ethylene-vinyl acetate copolymer composition obtained by graft polymerization or mixing a predetermined amount of a polyvinyl alcohol polymer as a material of the waterproof sheet is used. Used. By chemically adhering the composition and the secondary lining concrete, a gap is prevented from being formed at the joint interface between the waterproof sheet and the secondary lining concrete.

Japanese Patent No. 4511758

The waterproof sheet of Patent Document 1 requires special production equipment, is not easy to manufacture, and is expensive. Further, since the waterproof sheet and the secondary lining concrete are brought into close contact with each other, the secondary lining concrete is likely to crack due to drying shrinkage or the like.
In view of such circumstances, it is a main object of the present invention to provide an inexpensive waterproof sheet that can prevent water leakage by being in close contact with secondary lining concrete. Furthermore, the second problem is to prevent the secondary lining concrete from cracking by providing the waterproof sheet with an isolation (edge cutting) function.

In order to solve the above problems, the present invention is a waterproof sheet stretched between a primary lining concrete and a secondary lining concrete of a tunnel,
A waterproof layer,
A drainage layer laminated on the primary lining concrete side surface in the waterproof layer;
A concrete bonding layer laminated on the surface of the secondary lining concrete in the waterproof layer and bonded to the secondary lining concrete;
The concrete joint layer includes an embedded portion and a filling space portion defined by the embedded portion, and the embedded portion and the filling space portion are distributed over substantially the entire area of the concrete joint layer, respectively. The embedded portion is embedded in the secondary lining concrete, and the filling space portion is filled with the secondary lining concrete.

When the embedded portion is embedded in the secondary lining concrete and the filling space portion is filled with the secondary lining concrete, the concrete joining layer and the secondary lining concrete are physically brought into close contact with each other. Can be made.
When the spring water from the ground reaches the waterproof sheet through the primary lining concrete, it can be drained along the drainage layer, and the waterproof layer prevents water leakage into the secondary lining concrete side and thus into the tunnel. it can.
Even if a hole is formed in the waterproof layer of the waterproof sheet or a crack occurs in the secondary lining concrete, the concrete bonding layer and the secondary lining concrete are in close contact with each other. To the passage of water from the secondary lining concrete to the crack. Accordingly, water leakage into the tunnel can be prevented more reliably.
Since the waterproof sheet has a relatively simple structure, it can be manufactured at a low cost. As a result, construction costs can be reduced.
“Substantially the entire area” means that it is sufficient that the embedding part and the filling space part are distributed almost all over the concrete joint layer. For example, in the joint part between adjacent waterproof sheets, one of the waterproof sheets is used. It is only necessary to have an embedding part and a filling space part, and the other waterproof sheet does not need to have an embedding part and a filling space part.

The concrete joint layer is preferably a net-like body. The net material of the net-like body becomes the embedding part. The mesh of the mesh body is a filling space portion.
The concrete joint layer may include a sheet part and a convex part formed so as to be distributed substantially over the entire surface of the sheet part on the secondary lining concrete side. A convex part becomes an embedding part. A recessed portion other than the convex portion in the sheet portion becomes a filling space portion.

It is preferable that an easily peelable layer is interposed between the waterproof layer and the concrete bonding layer.
Thereby, the second problem can be solved. That is, when the secondary lining concrete shrinks by drying, the easily peelable layer is peeled off from the waterproof layer, so that the waterproof sheet has an isolation function and the secondary lining concrete is restrained by the primary lining concrete. Can be avoided. Thereby, it is possible to prevent the secondary lining concrete from being cracked. As a result, water leakage into the tunnel can be prevented more reliably.

According to the waterproof sheet of the present invention, water leakage into the tunnel can be prevented by physically contacting the secondary lining concrete even if the waterproof sheet has a hole. Moreover, it can be manufactured at low cost.
Furthermore, if an easy-peeling layer is interposed between the waterproof layer and the concrete joint layer, cracks can be prevented from occurring during drying shrinkage of the secondary lining concrete, and as a result, water leakage into the tunnel can be further ensured. Can be prevented.

FIG. 1 is a front sectional view illustratively showing a tunnel including a waterproof sheet according to the first embodiment of the present invention. FIG. 2A is an enlarged sectional view illustratively showing the waterproof sheet. FIG. 2B is an enlarged cross-sectional view of the circle IIb in FIG. FIG. 3 is a perspective view of a concrete bonding layer of the waterproof sheet. FIG. 4A is an enlarged plan view of a part of the concrete joint layer. FIG.4 (b) is an enlarged top view which shows the said concrete joint layer in the state embedded in the secondary lining concrete. FIG. 5A is an enlarged cross-sectional view illustratively showing the waterproof sheet according to the second embodiment of the present invention. FIG.5 (b) is an expanded sectional view of a part of tunnel containing the waterproof sheet of the figure (a). FIG. 6 is an enlarged cross-sectional view of a part of a tunnel including a waterproof sheet according to the third embodiment of the present invention. FIG. 7 is a perspective view of a concrete joint layer according to the third embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
As shown in FIG. 1, the tunnel 1 includes a primary lining concrete 3 on the natural ground 2 side and a secondary lining concrete 4 on the inner side of the tunnel. A lock bolt 6 is driven from the primary lining concrete 3 to the natural ground 2.
A waterproof sheet 10 is stretched between the primary lining concrete 3 and the secondary lining concrete 4.

As shown in FIG. 2, the waterproof sheet 10 includes a waterproof layer 11, a drainage layer 12, and a concrete bonding layer 20.
In FIG. 2B, the thickness of each layer 11, 12, 20 of the waterproof sheet 10 is exaggerated with respect to the thickness of the primary lining concrete 3.

The waterproof layer 11 is preferably composed of a sheet made of ethylene / vinyl acetate copolymer resin (EVA).
The material of the waterproof layer 11 is not necessarily limited to EVA, but a completely nonpolar polyolefin resin such as polyethylene (PE) or polypropylene (PP), or a polar group (carboxyl group) such as acrylic acid or maleic anhydride on PE or PP. ) May be graft polymerized to impart polarity, and thus a modified polyolefin resin or the like imparted with adhesiveness may be used.

A drainage layer 12 (buffer layer) is laminated on the surface of the waterproof layer 11 on the primary lining concrete 3 side.
The drainage layer 12 is composed of a nonwoven fabric. Nonwoven fabric materials include chemical fibers such as polyester and polypropylene, palm fibers, natural fibers such as cotton, hemp, wool, and silk, and inorganic fibers such as glass, carbon, metal, and ceramic. Is preferably a long-fiber chemical fiber.

The waterproof layer 11 and the drainage layer 12 are joined by hot air welding, for example. The joining means is not limited to welding, and adhesion using an adhesive such as hot melt resin may be applied.
At the side end portion of the waterproof sheet 10, the waterproof layer 11 and the drainage layer 12 are separated from each other for free connection with the adjacent waterproof sheet 10.

  A concrete bonding layer 20 is laminated on the surface of the waterproof layer 11 on the secondary lining concrete 4 side. The waterproof layer 11 and the concrete joining layer 20 are joined by joining means such as welding or adhesion.

As shown in FIG. 3, the concrete joining layer 20 is comprised with the three-dimensional net-like body 20x. The mesh body 20x includes a large number of linear mesh materials 21 and has a three-dimensional network structure. The material of the net member 21 is, for example, a synthetic resin such as polypropylene (PP), polyethylene (PE), polyamide, or polyester. Each net | network material 21 is changing the direction irregularly in the thickness direction of a waterproof sheet 10, and an in-plane direction, and is extended so that it may wave. As shown in FIGS. 3 and 4 (a), a plurality of net members 21, 21,... Intersect each other. The intersecting portion 21c between the net members 21, 21 is joined by adhesion or welding. A large number of meshes 22 (holes) are formed by the mesh materials 21, 21.
As the concrete bonding layer 20, a planar mesh body may be used instead of the three-dimensional mesh body 20x.

  As shown in FIG. 2A, the mesh material 21 and the mesh 22 are distributed over substantially the entire area of the concrete bonding layer 20, respectively. As shown in FIGS. 2 (b) and 4 (b), a net member 21 (embedded portion) is embedded in the secondary lining concrete 4. The mesh 22 (filling space) is filled with the secondary lining concrete 4.

Tunnel 1 is constructed as follows.
As shown in FIG. 1, the natural ground 2 is excavated by blasting or machine digging, a supporting work (not shown) is built along the excavated surface, the primary lining concrete 3 is sprayed, and the rock bolt 6 is applied to the natural ground 2. Type in.
Subsequently, the waterproof sheet 10 is stretched on the inner peripheral surface of the primary lining concrete 3. At this time, the drainage layer 12 is directed to the primary lining concrete 3 side, and the concrete joint layer 20 is directed to the tunnel inner side. Nails are driven at regular intervals to fix the waterproof sheet 10 to the primary lining concrete 3.
A plurality of waterproof sheets 10 are prepared, and each waterproof sheet 10 is stretched across the tunnel 1 in the transverse direction (circumferential direction). In addition, the waterproof sheets 10 are sequentially added in the longitudinal direction of the tunnel 1 (axial direction orthogonal to the paper surface of FIG. 1). Although illustration is omitted, the end portions of the waterproof layers 11, 11 of the adjacent waterproof sheets 10, 10 are fused and integrated.

  Next, as shown in FIG. 2 (b), the secondary lining concrete 4 is placed on the inner peripheral side of the waterproof sheet 10. Then, the cement particles of the secondary lining concrete 4 enter the mesh 22 and are filled. And the net material 21 is embedded in the secondary lining concrete 4. Thereby, the waterproof sheet 10 and the secondary lining concrete 4 can be physically adhered.

  According to the tunnel 1 constructed in this way, when the spring water from the natural ground 2 passes through the primary lining concrete 3 and reaches the waterproof sheet 10, the drainage layer 12 becomes a passage for water. And the waterproof layer 11 can prevent the spring water from flowing into the secondary lining concrete 4 side. This can prevent water leakage into the tunnel.

Even if the hole 11c is opened in the waterproof layer 11 of the waterproof sheet 10 or the crack 4c is generated in the secondary lining concrete 4, the concrete bonding layer 20 and the secondary lining concrete 4 are in close contact with each other. The passage of water from the hole 11c to the crack 4c can be blocked. Accordingly, water leakage into the tunnel can be prevented more reliably.
Since the waterproof sheet 10 has a relatively simple structure, it can be manufactured at low cost. Therefore, construction costs can be reduced.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are given to the drawings for the same configurations as those already described, and the description thereof is omitted.
Second Embodiment
FIG. 5 shows a second embodiment of the present invention. As shown to Fig.5 (a), in the waterproof sheet 10B of 2nd Embodiment, the easily peelable layer 13 is interposed between the waterproof layer 11 and the concrete joining layer 20. As shown in FIG. The material of the easily peelable layer 13 is preferably different from the material (EVA) of the waterproof layer 11, for example, a resin mainly composed of a polyolefin-based resin, and more preferably a resin mainly composed of polyethylene (PE). Yes, you may mix | blend an additional component suitably.
Furthermore, it is preferable that the easy peeling layer 13 has impermeableness.

The easy peeling layer 13 is joined to the waterproof layer 11 so as to be peelable by welding or the like. Since there is a difference in melting point between the easily peelable layer 13 and the waterproof layer 11, the peel strength can be adjusted by setting the welding temperature. In particular, by forming the easy peel layer 13 from polyethylene (PE), the melting point difference from the waterproof layer 11 made of EVA can be increased, and the peel strength can be easily adjusted.
The peel strength of the easily peelable layer 13 is preferably about 20 mN / 50 mm to 110 mN / 50 mm when measured by a peel force measurement method based on JIS Z 0237. If the peel strength is 20 mN / 50 mm or less, there is a risk of peeling due to its own weight. When the peel strength is 110 mN / 50 mm or more, peeling during secondary shrinkage of the secondary lining concrete 4 described later is less likely to occur.

  The concrete bonding layer 20 is bonded to the easy peeling layer 13. A concrete bonding layer 20 is laminated on the surface of the waterproof layer 11 on the side of the secondary lining concrete 4 with an easily peelable layer 13 interposed therebetween. Preferably, the bonding strength between the easily peelable layer 13 and the concrete bonding layer 20 is higher than the bonding strength between the easily peelable layer 13 and the waterproof layer 11.

  As shown in FIG. 5 (b), in the second embodiment, after the secondary lining concrete 4 is placed, when the dry shrinkage occurs, the easily peelable layer 13 is peeled off from the waterproof layer 11. The secondary lining concrete 4 can be prevented from being restrained by the primary lining concrete 3. Thereby, an isolation effect is expressed and it is possible to prevent the secondary lining concrete 4 from being cracked.

A gap may be formed between the easy peeling layer 13 and the waterproof layer 11 by the peeling. For this reason, if the hole 11 c is opened in the waterproof layer 11 of the waterproof sheet 10, the spring water from the natural ground 2 passes through the hole 11 c and enters the gap between the easily peelable layer 13 and the waterproof layer 11. Get in. On the other hand, since the easy-peeling layer 13 is impermeable, spring water cannot permeate the easy-peeling layer 13, and is drained through the gap between the easy-peeling layer 13 and the waterproof layer 11. Therefore, water leakage into the tunnel can be prevented.
Even if the spring water permeates the easy-peeling layer 13, the concrete bonding layer 20 and the secondary lining concrete 4 are in close contact with each other, so that water cannot be transmitted to the crack 4c. This can more reliably prevent water leakage into the tunnel.

The concrete bonding layer is not limited to the mesh body 20x as long as it can physically adhere to the secondary lining concrete 4.
<Third Embodiment>
6 and 7 show a third embodiment of the present invention. As shown in FIG. 6, the concrete bonding layer 30 of the waterproof sheet 10 </ b> C in the third embodiment is configured by a resin sheet, and includes a sheet portion 31 and a convex portion 32. The material of the concrete bonding layer 30 is, for example, a polyolefin resin such as polyethylene (PE) or polypropylene (PP).
The surface on the waterproof layer 11 side (upper surface in FIG. 6) of the sheet portion 31 is flat. A convex portion 32 is formed on the surface of the sheet portion 31 on the secondary lining concrete 4 side (the lower surface in FIG. 6).

As shown in FIG. 7, the convex portion 32 includes a large number (a plurality) of first protrusions 32 a extending in parallel with the first direction and a large number (a plurality of) second protrusions 32 b extending in parallel with the second direction. The protrusions 32a and 32b intersect each other to form a lattice pattern. The 1st protrusion 32a and the 2nd protrusion 32b may be orthogonal, and may cross | intersect diagonally.
The inside of each cell of the grid-like convex portion 32 is a concave portion 33. A large number of concave portions 33 are formed by the large number of protrusions 32a and 32b.
The convex portion 32 and the concave portion 33 are distributed substantially throughout the sheet portion 31.

As shown in FIG. 6, the convex portion 32 (embedding portion) is embedded in the secondary lining concrete 4 by placing the secondary lining concrete 4. In addition, the secondary lining concrete 4 enters and fills the concave portion 33 (filling space portion). Thereby, the concrete joining layer 30 and the secondary lining concrete 4 are physically adhered.
Therefore, even if the hole 11c is opened in the waterproof layer 11 of the waterproof sheet 10C, and even if the hole 30c is opened in the concrete bonding layer 30 itself, the space between the concrete bonding layer 30 and the secondary lining concrete 4 Since the water passage is blocked, the water cannot reach the crack 4c, and water leakage into the tunnel can be prevented.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the concrete joining layer may be comprised with the nonwoven fabric. Each fiber (embedded portion) of the nonwoven fabric is embedded in the secondary lining concrete 4 and the cement particles of the secondary lining concrete 4 are filled in the filling space between the fibers, thereby making the concrete joint made of the nonwoven fabric. The layer and the secondary lining concrete 4 may be physically adhered. The nonwoven fabric is preferably a thin non-woven fabric from the viewpoint of the bondability with the secondary lining concrete 4 and the bondability with the waterproof layer 11 or the easily peelable layer 13, and is a short fiber rather than a long fiber. It is preferable that it is manufactured by a needle punch method. As the material of the nonwoven fabric, chemical fibers such as polyester and polypropylene, palm fibers, natural fibers such as cotton, hemp, wool, and silk, inorganic fibers such as glass, carbon, metal, and ceramic can be used.

An easily peelable layer 13 may be interposed between the waterproof layer 11 and the concrete bonding layer 30 in the waterproof sheet 10 </ b> C of the third embodiment (FIG. 6). The concrete bonding layer 30 may also serve as the easily peelable layer 13 by being detachably bonded to the waterproof layer 11.
In the third embodiment (FIG. 6), a large number of small-diameter circular or non-circular convex portions may be distributed (distributed) over almost the entire area of the sheet portion 31 instead of the lattice-shaped convex portions 32. Good.
From the standpoint of suppressing cracking during drying shrinkage of secondary lining concrete due to the isolation effect, a concrete joint layer that is chemically in close contact with secondary lining concrete 4 as in Patent Document 1, and easy peeling A waterproof sheet combined with the layer 13 may be used.

  The present invention can be applied to a waterproof structure of an inner wall of a tunnel.

DESCRIPTION OF SYMBOLS 1 Tunnel 2 Ground mountain 3 Primary lining concrete 4 Secondary lining concrete 6 Rock bolt 10 Waterproof sheet 10B, 10C Waterproof sheet 11 Waterproof layer 12 Drain layer 13 Easily peelable layer 20 Concrete joint layer 20x Reticulated body 21 Net material (embedding part) )
21c intersection 22 mesh (filling space)
30 Concrete bonding layer 31 Sheet part 32 Convex part (embedding part)
33 Recess (filling space)

Claims (4)

A waterproof sheet stretched between the primary lining concrete and secondary lining concrete of the tunnel,
A waterproof layer,
A drainage layer laminated on the primary lining concrete side surface in the waterproof layer;
A concrete bonding layer laminated on the surface of the secondary lining concrete in the waterproof layer and bonded to the secondary lining concrete;
The concrete joint layer includes an embedded portion and a filling space portion defined by the embedded portion, and the embedded portion and the filling space portion are distributed over substantially the entire area of the concrete joint layer, respectively. The waterproof sheet is characterized in that the embedded portion is embedded in the secondary lining concrete, and the filling space portion is filled with the secondary lining concrete.   The waterproof sheet according to claim 1, wherein the concrete bonding layer is a net-like body.   The said concrete joining layer contains a sheet | seat part and the convex part formed so that it might be distributed over the substantially whole region of the surface at the side of the secondary lining concrete of the said sheet | seat part. Tarpaulin.   The waterproof sheet according to any one of claims 1 to 3, wherein an easily peelable layer is interposed between the waterproof layer and the concrete bonding layer.

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