JP2023051185A - Waterproof sheet for tunnel and manufacturing method thereof - Google Patents

Abstract

To provide a waterproof sheet for a tunnel including a three-dimentional mesh and excellent in processability of an attachment piece to be attached to a primary covering concrete surface of the tunnel, and a manufacturing method thereof.SOLUTION: The present invention relates to a waterproof sheet 1 for a tunnel including an impermeable layer 2, a permeable layer 3, a three-dimensional mesh 4, and an attachment piece 5 to be attached to a primary lining concrete surface of the tunnel, wherein the impermeable layer 2, the permeable layer 3 and the three-dimensional mesh body 4 are laminated in this order, and the three-dimensional mesh body 4 has a low basis weight zone at a central portion in a width direction, which has a lower basis weight than other parts, the attachment piece 5 is arranged on a surface on a side opposite to the permeable layer 3 of the three-dimensional mesh body 4, the attachment piece 5 and the permeable layer 3 are joined to each other with the three-dimensional net-like body 4 interposed therebetween, joining parts 7 exist parallel with a longitudinal direction of the waterproof sheet 1 for the tunnel, and a portion of the three-dimensional mesh 4 sandwiched by the joint parts 7 is located in the low basis weight zone.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a tunnel waterproof sheet for discharging spring water that flows out from primary lining concrete on the ground side in tunnel construction, and a method for manufacturing the same.

The New Austrian Tunneling Method (hereinafter also referred to as NATM) is known as one of the tunneling methods in mountainous areas. In NATM, after excavation, concrete is usually sprayed on the tunnel excavation wall (primary lining concrete), rock bolts are inserted toward the inside of the ground, and then after the displacement of the inner space has stabilized, waterproofing is applied to the primary lining concrete surface. The sheet is installed and then the secondary lining concrete is placed.

The waterproof sheet plays a role of discharging the spring water flowing out from the primary lining concrete surface to the outside and preventing the spring water from flowing out to the secondary lining concrete side. Conventionally, as such a waterproof sheet, for example, as described in Patent Document 1, one in which a water-impermeable sheet made of synthetic resin and a water-permeable mat made of nonwoven fabric are integrated has been used. there is In recent years, in order to improve the drainage performance, for example, as described in Patent Document 2, a water-conducting layer made of a three-dimensional mesh has been proposed.

Japanese Utility Model Laid-Open No. 61-58299 JP 2017-166149 A

On the other hand, in order to suppress the slack of the intermediate portion of the sheet when constructing the waterproof sheet, for example, as in Patent Document 1, by providing an attachment piece for intermediate fixing, the intermediate portion of the sheet can be attached to the primary lining concrete surface. Fixing is being done.
However, in the case of a waterproof sheet including a three-dimensional net-like body as described in Patent Document 2, it is difficult to join the attachment pieces for intermediate fastening, and when joining the attachment pieces for intermediate fastening by sewing, needles are required during sewing. comes into contact with the filaments forming the three-dimensional mesh, causing frequent needle breakage and thread breakage.

In order to solve the above conventional problems, the present invention provides a waterproof sheet for tunnels, which includes a three-dimensional net-like body and has good workability of attachment pieces to be attached to the primary lining concrete surface of tunnels, and a method for manufacturing the same.

The present invention is a waterproof sheet for tunnels comprising an impermeable layer, a permeable layer, a three-dimensional net-like body, and attachment pieces to be attached to a primary lining concrete surface of a tunnel, wherein the impermeable layer, the permeable layer and the three-dimensional net-like body are , an impermeable layer, a permeable layer, and a three-dimensional net-like body are laminated in this order. is arranged on the surface of the three-dimensional mesh body opposite to the water permeable layer, and the mounting piece and the water permeable layer are joined to each other with the three-dimensional mesh body sandwiched therebetween, and the junction is a tunnel waterproof The part of the three-dimensional net-like body that exists parallel to the longitudinal direction of the sheet and is sandwiched between the joints relates to the waterproof sheet for tunnels, which is located in the low mesh area.

The present invention also relates to a method for manufacturing a waterproof sheet for a tunnel, which includes an impermeable layer, a permeable layer, a three-dimensional mesh body, and an attachment piece to be attached to the primary lining concrete surface of the tunnel, wherein the three-dimensional mesh body is placed in the center in the width direction. A step of providing a three-dimensional net-like body with a low mesh area having a lower basis weight than other parts by manufacturing using a spinning nozzle in a state where some of the existing holes are closed, and a laminate of the three-dimensional net-like body and the permeable layer. In the above, an attachment piece is superimposed on the surface of the low mesh band on the opposite side of the water permeable layer of the three-dimensional net, and the joint of the attachment piece and the water permeable layer is parallel to the longitudinal direction of the waterproof sheet for tunnels. and a step of laminating and integrating a water impermeable layer on the surface of the water permeable layer.

INDUSTRIAL APPLICABILITY The present invention can provide a waterproof sheet for tunnels, which includes a three-dimensional net-like body and has good workability of attachment pieces attached to the primary lining concrete surface of a tunnel, and a method for manufacturing the same.
According to the manufacturing method of the present invention, it is possible to provide a tunnel waterproof sheet including a three-dimensional net-like body with an attachment piece to be attached to the primary lining concrete surface of a tunnel with good workability.

FIG. 1 is a schematic exploded perspective view of a waterproof sheet for tunnels as an example of the present invention. FIG. 2 is a schematic perspective view of a waterproof sheet for tunnels as an example of the present invention.

The inventor of the present invention has made a study to improve the workability of a tunnel waterproof sheet having a three-dimensional net-like body (hereinafter also simply referred to as a net-like body) in the case of providing attachment pieces for attachment to the primary lining concrete surface of the tunnel. repeated. As a result, a low mesh area with a lower basis weight (mass per unit area) than other parts is provided in the center of the three-dimensional mesh in the width direction, and when the impervious layer and the permeable layer are joined across the three-dimensional mesh, It has been found that, by locating the portion of the three-dimensional net-like body sandwiched between the joints in the low mesh area, almost no process defects occur in the joining process, and workability is improved.

The waterproof sheet for tunnels includes an impermeable layer, a permeable layer, a three-dimensional mesh, and attachment pieces (hereinafter simply referred to as "attachment pieces") for attachment to the primary lining concrete surface of the tunnel. FIG. 1 is a schematic exploded perspective view of a waterproof sheet for tunnels of one example of the present invention, and FIG. 2 is a schematic perspective view of the same. As shown in FIG. 1, in the tunnel waterproof sheet 1, the impermeable layer 2, the permeable layer 3, and the three-dimensional mesh 4 are laminated in this order. 3 is located on the opposite surface. The impermeable layer 2 is dot-bonded to the permeable layer 3 with an adhesive 6 arranged at predetermined intervals. The mounting piece 5 and the permeable layer 3 are joined 7 with the three-dimensional mesh 4 interposed therebetween. In FIGS. 1 and 2, the joint 7 is stitched by a sewing machine or the like. 1 and 2, LD indicates the longitudinal direction and WD indicates the width direction. LD and WD are orthogonal.

In FIG. 1, the joining 7 (stitching) is performed by two joining lines (sewing lines) substantially parallel to each other. You may carry out by the joining line (sewing line) more than this. From the viewpoint of convenience and productivity, it is preferable that the joining 7 (stitching) is performed by two joining lines (sewing lines) substantially parallel to each other.

<Water shielding layer>
The impermeable layer plays a role in preventing spring water from migrating to the concrete side. For example, in tunnel construction, by installing a waterproof sheet for tunnels on the primary lining concrete side, it is possible to prevent spring water generated from the underground side from flowing out to the secondary lining concrete side beyond the impermeable sheet. do. If spring water migrates to the secondary lining concrete side, the secondary lining concrete is likely to crack, and the concrete may collapse.

The impermeable layer is not particularly limited as long as it is composed of a sheet impermeable to water. The impermeable layer can be composed of, for example, a resin sheet. The resin sheet may contain 20% to 90% by mass of ethylene-vinyl acetate copolymer and 10% to 90% by mass of polyethylene. When the content of the ethylene-vinyl acetate copolymer in the resin sheet is 20% by mass or more, the resin sheet has good water impermeability due to the resin properties of the ethylene-vinyl acetate copolymer. Furthermore, due to the resin properties of the ethylene-vinyl acetate copolymer, the waterproof sheet does not harden even in a low-temperature environment of, for example, 10°C or less, and the conformability to the construction surface is maintained. From the viewpoint of obtaining such effects more remarkably, the resin sheet preferably contains an ethylene-vinyl acetate copolymer in an amount of 40% by mass or more, more preferably 60% by mass or more, particularly 70% by mass or more. preferable. When the content of polyethylene in the resin sheet is 10% by mass or more, it is possible to obtain a resin sheet having excellent adhesion to the nonwoven fabric forming the water-permeable layer. In addition, from the viewpoint of not reducing the flexibility and tensile strength of the waterproof layer, the resin sheet preferably contains 60% by mass or less of polyethylene, more preferably 40% by mass or less, and particularly 30% by mass or less. preferable.

The ethylene-vinyl acetate copolymer preferably has a vinyl acetate content of 3% by mass or more and 50% by mass or less. When the vinyl acetate content in the ethylene-vinyl acetate copolymer is 3% by mass or more, a sheet with excellent flexibility can be obtained. Further, when the vinyl acetate content is 50% by mass or less, even when the waterproof sheet for tunnels is stored in an environment of 30°C or higher, the impermeable layers stick together and become integrated (blocking). There are few things. From the viewpoint of obtaining such effects more remarkably, the vinyl acetate content is more preferably 5% by mass or more and 40% by mass or less, and further preferably 10% by mass or more and 30% by mass or less.

One or more selected from the group consisting of high-density polyethylene, low-density polyethylene, and linear low-density polyethylene can be used as the polyethylene. When high-density polyethylene is used, a resin sheet having excellent impact resistance can be obtained due to its resin characteristics. In addition, when low-density polyethylene is used, it is possible to obtain a resin sheet having excellent heat-welding properties due to its resin characteristics. Among them, polyethylene is preferably linear low-density polyethylene. Resin sheets comprising linear low density polyethylene have particularly good tensile strength. When the resin sheet is excellent in tensile strength, the impermeable layer is difficult to break.

The above polyethylene has a melt flow rate (hereinafter also referred to as MFR) at 190 ° C. (load 2.16 kgf (21.18 N)) measured according to JIS K 7210-1 (2014) is 1 g / 10 minutes or more and 10 g / 10 minutes or less. When the MFR of polyethylene is 1 g/10 minutes or more, it is easy to produce a waterproof sheet. When the MFR of polyethylene is 10 g/10 minutes or less, there is little possibility that the strength of the impermeable sheet is lowered. From the viewpoint of obtaining such effects more remarkably, the MFR of polyethylene is more preferably 1.5 g/10 min or more and 7 g/10 min or less.

The resin sheet may contain other resins in addition to the ethylene-vinyl acetate copolymer and polyethylene. The content of other resins is preferably 30% by mass or less, more preferably 10% by mass or less, relative to the total mass of the resin sheet. Other resins are not particularly limited. Polyolefin resins such as vinyl alcohol copolymers can be used. Moreover, the resin sheet may contain an antioxidant, a heat stabilizer, or the like in an amount of 10% by mass or less with respect to the total mass of the impermeable sheet, if necessary.

The resin sheet is not particularly limited, but preferably has a thickness of 0.10 mm or more and 3.0 mm or less, more preferably 0.30 mm or more and 2.0 mm or less. When the thickness of the impermeable layer is 0.10 mm or more and 3.0 mm or less, the waterproof sheet for tunnels is excellent in handleability during construction. The thickness of the resin sheet is measured according to JIS A 6008 (2006) 8.2. That is, the thickness is measured according to JIS K 6250 (2019) 10.2 (A method) for the measurement points described in this method.

The resin sheet is not particularly limited, but from the viewpoint of handling during construction, the basis weight (mass per unit area) measured according to JIS A 6008 (2006) 8.4 is 700 g / m ² or more and 1000 g / It is preferably m ² or less, more preferably 750 g/m ² or more and 900 g/m ² or less.

The resin sheet preferably has a tensile strength (tensile strength at break) measured according to JIS K 6251 (2017) of 10 N/mm ² or more, more preferably 16 N/mm ² or more. . When the tensile strength is 10 N/mm ² or more, the resin sheet is less likely to break. A preferable upper limit of the tensile strength is 100 N/mm ² or less. The test piece used for measuring the tensile strength is JIS K 7127 (1999) test piece type 5.

The resin sheet preferably has an elongation (elongation at break) of 500% or more, more preferably 600% or more, measured according to JIS K 6251 (2017). When the elongation rate is 500% or more, it becomes easy to construct the waterproof sheet for tunnel along the arc surface of the tunnel. A preferable upper limit of the elongation rate is 1000% or less. The test piece used for measuring elongation is the same as the test piece used for measuring tensile strength.

The resin sheet has a tear strength of 400 N/cm or more measured according to JIS K 6252 (2015) 4.3 Test Method B-Procedure (a): A method using an angle-shaped test piece without cuts. It is preferably 500 N/cm or more, and more preferably 500 N/cm or more. When the tear strength is 400 N/cm or more, the resin sheet is difficult to tear. A preferable upper limit of the tear strength is 2000 N/cm or less.

The resin sheet is produced, for example, by melting a resin composition containing an ethylene-vinyl acetate copolymer and polyethylene, extruding it through a T-die, adjusting the thickness between metal rolls, and forming a sheet of a predetermined thickness. can be made with At this time, the ethylene-vinyl acetate copolymer and polyethylene may be mixed in advance to form a masterbatch. Furthermore, additives such as hindered phenol-based antioxidants, phosphorus-based heat stabilizers, and hydroxyamine-based heat stabilizers may be added as necessary. In addition, the impermeable sheet may be stretched as necessary.

<Permeable layer>
The water-permeable layer can be made of nonwoven fabric. The nonwoven fabric is not particularly limited, but for example, either a long fiber nonwoven fabric or a short fiber nonwoven fabric may be used. Examples of long-fiber nonwoven fabrics include spunbond nonwoven fabrics and meltblown nonwoven fabrics. Examples of staple fiber nonwoven fabrics include needle-punched nonwoven fabrics, spunlaced nonwoven fabrics and thermal-bonded nonwoven fabrics. Alternatively, a long-fiber nonwoven fabric or a short-fiber nonwoven fabric treated with a binder resin may be used.

The fibers constituting the nonwoven fabric are not particularly limited, but for example, polyolefin resins such as polyethylene, polypropylene, and polybutene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and synthetic resins such as polyamide resins such as nylon 6 and nylon 66. Constituent fibers can be mentioned. Among them, the fibers constituting the nonwoven fabric preferably contain a polyester resin from the viewpoint of excellent strength and bulkiness of the nonwoven fabric.

The fibers constituting the nonwoven fabric are not particularly limited, but the single fiber fineness may be 1 dtex or more and 100 dtex or less, 2 dtex or more and 80 dtex or less, or 4 dtex or more and 60 dtex or less. When the fineness is within the range described above, the tensile strength and tear strength of the nonwoven fabric can be enhanced.

The thickness of the nonwoven fabric is preferably 0.50 mm or more and 20 mm or less, more preferably 0.60 mm or more and 10 mm or less, still more preferably 0.70 mm or more and 5.0 mm or less, and particularly preferably 0.90 mm. It is more than 3.0 mm or less. When the thickness of the nonwoven fabric is 0.50 mm or more, the effect of preventing the impermeable sheet from being damaged by projections is higher. When the thickness of the nonwoven fabric is 20 mm or less, it is difficult for the nonwoven fabric to break or peel in the thickness direction. The thickness of the nonwoven fabric is measured under a load of 1.96 kPa according to JIS L 1096 (2010) 8.4.

The nonwoven fabric preferably has a basis weight (mass per unit area) of 80 g/m ² or more and 250 g/m ² or less, more preferably 120 g/m ² or more and 200 g/m ² or less. When the fabric weight of the nonwoven fabric is 80 g/m ² or more, the tensile strength is high and it is difficult to break. In addition, when the nonwoven fabric has a basis weight of 250 g/m ² or less, it does not become too heavy, and construction is easy. The basis weight of the nonwoven fabric is measured according to JIS L 1096 (2010) 8.3.

The nonwoven fabric is not particularly limited, but preferably has a tensile strength of 200 N/5 cm or more, measured according to JIS L 1096 (2010) 8.14 A method (strip method), and preferably 250 N/5 cm or more. It is more preferable to have When the tensile strength is 200 N/5 cm or more, the nonwoven fabric is less likely to break. A preferable upper limit of the tensile strength is 1000 N/5 cm or less.

The nonwoven fabric is not particularly limited, but preferably has an elongation percentage of 20% or more, more preferably 50% or more, as measured according to JIS L 1096 (2010) 8.14 A method (strip method). more preferred. When the elongation rate is 20% or more, it becomes easy to follow the elongation of the resin sheet that constitutes the impermeable layer. Also, the elongation rate is preferably 90% or less, more preferably 80% or less. When the elongation rate of the nonwoven fabric is 90% or less, it is difficult for spring water and sediment to accumulate between the permeable layer and the three-dimensional net-like body, and the space between the permeable layer and the impermeable layer tends to function as a water conduit. Water can be drained.

Although the nonwoven fabric is not particularly limited, the tear strength measured according to JIS L 1096 (2010) 8.17 A-1 method (single tongue method) is preferably 50 N or more, and 60 N or more. is more preferable. When the tear strength is 50 N or more, the nonwoven fabric is difficult to tear. A preferable upper limit of the tear strength is 150N or less.

The nonwoven fabric may be composed of one type of fiber, or may be a nonwoven fabric in which two or more fibers are mixed. Further, the nonwoven fabric may be a single-layer nonwoven fabric consisting of a web of one layer, or a laminated nonwoven fabric formed by laminating two or more layers of webs. Further, the nonwoven fabric may be composed of fibers made of a single component resin, or may be composed of composite fibers using two or more resins.

<Three-dimensional mesh>
In the present invention, the three-dimensional netted body functions as a water conduit for draining spring water to the outside. Even if pressure is applied to the waterproof sheet for tunnels due to placing concrete or the weight of the soil, the water canal remains to some extent thick, allowing a larger amount of spring water to drain. can do. For example, when a waterproof sheet for tunnels is placed between the primary and secondary lining concrete of the tunnel so that the impermeable layer is on the secondary lining concrete side, seepage generated from the primary lining concrete side Water or the like is added between the permeable layer and the impermeable layer, passes through the voids of the three-dimensional mesh, and is discharged to the outside.

The three-dimensional network is formed by irregularly crossing a plurality of continuous filaments having a thickness (diameter) of 0.1 mm or more and 10 mm or less in the horizontal direction and/or the thickness direction. Since the filaments are continuous in the three-dimensional network body, compared to the case where the filaments are discontinuous, the number of filament tips is small, and the impermeable sheet is not damaged or damaged by the filament tips. The thickness of the continuous filament is preferably 0.3 mm or more and 5.0 mm or less, more preferably 0.5 mm or more and 3.0 mm or less. When the thickness of the continuous filament is 0.1 mm or more, the filament is difficult to break. Further, when the thickness of the continuous filaments is 10 mm or less, the adhesion intersections between the continuous filaments and between the continuous filaments and the non-woven fabric do not become too large, and the three-dimensional network forms appropriate voids. The thickness of the continuous filament is obtained by measuring the diameters of the continuous filament at arbitrary 100 points, and taking the average value as the thickness of the continuous filament.

The cross-sectional shape of the continuous filaments is not particularly limited, and may be any shape such as circular, elliptical, triangular, quadrangular, polygonal, Y-shaped, and cross-shaped. When the filament cross section is not circular, the thickness of the continuous filament is the diameter of a circle obtained by measuring the filament cross section and converting it into a circle having the same area as the cross section.

The resin constituting the continuous filaments is not particularly limited, but polyethylene (including copolymers of ethylene and olefins other than ethylene), polypropylene (including copolymers of propylene and olefins other than propylene), polybutene-1. polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyamide resins such as nylon 6 and nylon 66; and synthetic resins such as polystyrene (including hydrogenated polystyrene). Among them, polyolefin resins are preferable from the viewpoint of excellent alkali resistance and weather resistance. When the continuous filaments are made of polyolefin resin, the three-dimensional network structure has excellent alkali resistance, and the three-dimensional network structure is less likely to deteriorate even when an alkaline solution is generated from the placed concrete, for example.

Although the three-dimensional network body is not particularly limited, the total basis weight is preferably 200 g/m ² or more and 1000 g/m ² or less, more preferably 250 g/m ² or more and 700 g/m ² or less, and 300 g/m ² . More preferably, it is at least 600 g/m ² or less. When the basis weight is 200 g/m ² or more, it is easy to form voids that will serve as water conduits, and drainage performance is improved. When the total basis weight is 1000 g/m ² or less, it is easy to wind up and does not become too heavy, so that it can be easily placed on a concrete surface, for example. The overall basis weight of the three-dimensional net-like body is measured by taking a sample from a location other than the low mesh area described later and measuring it according to JIS L 1096 (2010) 8.3. When the three-dimensional net-like body is laminated and integrated with the permeable layer or the like, it may be calculated by subtracting the permeable weight of the permeable layer or the like measured in advance from the permeable weight of the laminate.

The three-dimensional netted body has a low mesh area that is lower in basis weight than other parts. As will be described later, by arranging the joints between the permeable layer and the attachment piece so as to sandwich the low-mesh attachment of the three-dimensional mesh, process defects when attaching the attachment piece are suppressed, and the workability of the attachment piece is improved. do. From the viewpoint of facilitating attachment of the intermediate portion of the prevention sheet to the primary lining concrete surface of the tunnel, it is preferable that the low mesh attachment be arranged in the central portion of the three-dimensional net-like body in the width direction and formed so as to be continuous in the longitudinal direction. . In the present invention, the other portions mean the portions on both sides of the width of the waterproof sheet for tunnels divided into three equal parts, excluding the central 1/3. The basis weight of the low mesh band is measured by taking a sample from the low mesh band and measuring it in the same manner as the overall basis weight described above. If the low mesh area is indistinguishable from other areas, it is preferable to measure the area of about 50 mm in the width direction centering on the joint area. If there are multiple joints in the width direction (two or more joint lines exist), the basis weight between the two outermost joints, or the middle of the two outermost joints It is preferable to measure the basis weight in a width of about 50 mm centered on the point. The basis weight of other parts is measured by collecting samples from other parts in the same manner as the total basis weight.

In the three-dimensional net-like body, the ratio of the basis weight of the low mesh area to the overall basis weight is preferably 0.30 or more and 0.90 or less, and more preferably 0.40 or more and 0.85 or less. As a result, workability of the mounting piece is improved, and high drainage performance can be maintained. In addition, in the three-dimensional net-like body, the difference between the total basis weight and the basis weight of the low mesh area is preferably 30 g/m ² or more, more preferably 60 g/m ² or more. The upper limit of the difference between the total basis weight and the basis weight of the low basis weight is preferably, for example, 500 g/m ² or less, more preferably 400 g/m ² or less.

The basis weight of the low mesh band is not particularly limited, but is preferably 80 g/m ² or more and 250 g/m ² or less, more preferably 100 g/m ² or more and 240 g/m ² or less, and 120 g/m ² or more. It is more preferably 230 g/m ² or less. As a result, workability of the mounting piece is improved, and high drainage performance can be maintained.

The width of the low mesh band is not particularly limited, but is preferably 50 mm or more, more preferably 80 mm or more, and even more preferably 100 mm or more. As a result, the joints between the water-permeable layer and the mounting pieces can be easily arranged so as to sandwich the low-mesh areas of the three-dimensional net-like body. The upper limit of the width of the low mesh band is, for example, preferably 400 mm or less, more preferably 300 mm or less, and even more preferably 200 mm or less. Thereby, high drainage performance can be maintained.

The ratio of the width of the low-mesh belt to the overall width of the three-dimensional network is not particularly limited, but is preferably 0.20 or less, more preferably 0.15 or less, and 0.10 or less. More preferred. Thereby, high drainage performance can be maintained. The lower limit of the ratio of the width of the low mesh area to the overall width of the three-dimensional mesh is preferably 0.025 or more, more preferably 0.040 or more, and even more preferably 0.050 or more. . As a result, the joining process of the mounting pieces is improved.

The three-dimensional net-like body is not particularly limited, but preferably has a thickness of 1.0 mm or more and 30 mm or less. When the thickness of the mesh is 1.0 mm or more, clogging is unlikely to occur and good water permeability can be obtained even when the spring water contains earth and sand. Moreover, when the thickness of the mesh is 30 mm or less, the nonwoven fabric and the mesh are less likely to separate. From the viewpoint of obtaining such effects more remarkably, the thickness of the three-dimensional mesh is preferably 2.0 mm or more and 10 mm or less. Moreover, the three-dimensional net-like body may have convex portions or concave portions in the thickness direction. The thickness of the three-dimensional mesh is measured under a load of 1.96 kPa according to JIS L 1096 (2010) 8.4. When the three-dimensional net-like body is laminated and integrated with the permeable layer or the like, the thickness may be calculated by subtracting the previously measured thickness of the permeable layer or the like from the thickness of the laminate.

For example, the three-dimensional mesh having a low mesh is melted by heating the resin constituting the three-dimensional mesh to about 200° C. or more and 350° C. or less, and the molten resin partially closes the holes present in the center in the width direction. It can be produced by extruding while rotating randomly from a spinning nozzle (spinning die) in a free state, and collecting irregularly intersecting continuous filaments on a collecting plate or a nonwoven fabric constituting a water-permeable layer. . If necessary, a pigment masterbatch such as a black pigment masterbatch may be blended with the resin constituting the three-dimensional network.

(Mounting piece)
The attachment piece is attached to the primary lining concrete surface of the tunnel, and fixes the intermediate portion of the tunnel waterproof sheet to the tunnel to suppress the occurrence of sagging. The attachment piece may be a belt-like piece formed continuously in the longitudinal direction of the waterproof sheet for tunnels, or may be a small rectangular piece arranged at regular intervals in the longitudinal direction of the waterproof sheet for tunnels. The material of the attachment piece is not particularly limited, and may be a nonwoven fabric or a woven or knitted fabric. A woven fabric can be preferably used from the viewpoint of strength. From the viewpoint of ease of handling, it is preferable that the attachment piece is a belt-shaped fabric that is continuously arranged in the longitudinal direction of the tunnel waterproof sheet.

The mounting pieces are joined to the water permeable layer with the three-dimensional net-like body sandwiched therebetween, and the joints exist parallel to the longitudinal direction of the tunnel waterproof sheet, and the three-dimensional net-like structure is sandwiched between the joints. The body part is located in the lower eye zone. As a result, process defects when joining the attachment piece and the permeable layer are suppressed, and the workability of the attachment piece is improved. The width of the mounting piece is not particularly limited, and can be appropriately set as required. The width of the mounting piece may be, for example, 200 mm or more and 500 mm or less, 250 mm or more and 400 mm or less, or 270 mm or more and 350 mm or less. The joint may be in the middle of the width direction of the attachment piece, or may be unevenly distributed on either side. When unevenly distributed, a fixing pin can be struck on the wider side. The bonding may be performed with one bonding line, or with two or more bonding lines substantially parallel to each other. From the viewpoint of convenience and productivity, it is preferable to perform the joining by two joining lines substantially parallel to each other. If another sheet (such as a non-woven fabric) is inserted between the attachment piece and the three-dimensional mesh, the attachment piece and the permeable layer may be joined through the three-dimensional mesh and the other sheet.

Examples of the method of joining the mounting pieces include joining by sewing, joining by adhesive, joining by heat welding, joining by tag pins, etc., but joining by sewing using a sewing machine is particularly preferable from the viewpoint of workability.

Bonding by sewing can be performed by sewing the permeable layer and the attachment piece together with a thread. Since the three-dimensional net-like body present at the joint has a low mesh, the needle can easily pass through, and needle breakage and thread breakage are less likely to occur.

Adhesive bonding can be performed by applying an adhesive between the water-permeable layer and the mounting piece. Since the three-dimensional net-like body present at the joining portion has a low-mesh attachment, the water-permeable layer and the attachment piece are easily brought into contact with each other, so that joining with an adhesive is facilitated.

Bonding by heat welding can be performed by melting and bonding one or both of the water-permeable layer and the mounting piece made of thermoplastic resin using ultrasonic waves or hot air. Since the three-dimensional net-like body present at the joining portion has a low-mesh attachment, the water-permeable layer and the attachment piece are easily brought into contact with each other, so that joining by heat welding is facilitated.

Bonding by tag pins is used for tagging clothing items, etc. A tag pin having T-shaped or arrowhead-shaped stoppers at both ends can be used to join the permeable layer and the attachment piece with a tag gun. can. Since the three-dimensional net-like body present at the joining portion has a low mesh, the needle of the tag gun can easily penetrate, so joining with the tag pin is facilitated.

The nonwoven fabric and the three-dimensional net-like body that constitute the water-permeable layer may be laminated and integrated via an adhesive, or may be laminated and integrated with a component that constitutes continuous filaments. It is preferable that the nonwoven fabric and the three-dimensional net-like body constituting the water-permeable layer are integrated by the components constituting the continuous filaments, and more preferably integrated by fusing the components constituting the continuous filaments. When the nonwoven fabric and the net-like body that constitute the water-permeable layer are integrated by the component that constitutes the continuous filaments, the water-permeable layer and the net-like body are less likely to separate. In addition, by filming the continuous filaments at the bonding points, the water-permeable layer and the net-like body can be more firmly integrated.

The nonwoven fabric forming the water-permeable layer and the resin sheet forming the impermeable layer may be bonded via an adhesive, or may be heat-sealed by the components forming the nonwoven fabric or the resin sheet. . The nonwoven fabric forming the water-permeable layer and the resin sheet forming the water-impermeable layer are preferably bonded together by a hot-melt adhesive or thermal welding.

The nonwoven fabric forming the water-permeable layer and the resin sheet forming the water-impervious layer are preferably adhered in a point-like manner or in a line-like manner. When the nonwoven fabric forming the permeable layer and the resin sheet forming the impermeable layer are adhered in a point or line form, the space between the nonwoven fabric and the resin sheet can easily function as a water conduit, and a large amount of spring water can be drained. can. When a large amount of spring water is generated, a space is formed in the non-bonded portion between the non-woven fabric and the resin sheet due to the water pressure, and this space becomes a water conduit for efficient drainage.

It is preferable that the adhesion interval of dot-like adhesion or linear adhesion is 2 cm or more and 70 cm or less. Here, the adhesion interval refers to the distance between two adjacent adhesion points in the case of point-like adhesion, and in the case of linear adhesion, another adhesion line that is closest in the direction perpendicular to the adhered linear part. It means the distance from the shape part. When the adhesion interval is 2 cm or more, a space is likely to be formed in the non-adhered portion, and when the adhesion interval is 70 cm or less, the nonwoven fabric and the impermeable sheet are less likely to be displaced during construction, making construction easier.

In particular, the nonwoven fabric forming the water-permeable layer and the resin sheet forming the water-impervious layer are adhered to each other by a hot-melt adhesive, and the adhesion interval is more preferably 10 cm or more and 50 cm or less. With such a configuration, the permeable layer and the impermeable layer are less likely to separate, and an excellent water conduit can be formed between the impermeable layer and the impermeable layer.

The waterproof sheet for tunnels preferably has a basis weight of 2.0 kg/m ² or less, more preferably 1.5 kg/m ² or less. When the waterproof sheet for tunnels has a basis weight of 2.0 kg/m ² or less, the waterproof sheet for tunnels is light and easy to construct. For example, it is easy to construct even when it is stretched on the ceiling of a tunnel. Although not particularly limited, the preferred lower limit is 0.50 kg/m ² or more.

Although the waterproof sheet for tunnels is not particularly limited, it can be produced, for example, as follows.
By manufacturing the three-dimensional network body using a spinning nozzle that partially blocks the holes present in the center in the width direction, the three-dimensional network body is provided with a low mesh area with a lower basis weight than other parts, and the three-dimensional network body and In the layered product with the permeable layer, the mounting piece is superimposed on the surface of the low-mesh side of the three-dimensional mesh on the opposite side of the permeable layer, and the joint between the mounting piece and the permeable layer is parallel to the longitudinal direction of the waterproof sheet for tunnels. A waterproof sheet for tunnels can be obtained by joining the two layers so that they are present as if they were firmly attached to each other, and laminating and integrating the impermeable layer on the surface of the permeable layer.

First, a spinning nozzle (spinning die) in a state in which the resin constituting the three-dimensional net-like body is heated to about 200° C. or higher and 350° C. or lower to melt, and the holes present in the central portion in the width direction are partially blocked by the molten resin. It is extruded while randomly rotating from the A non-woven fabric is laminated on the three-dimensional net-like body, and the non-woven fabric for the water-permeable layer and the three-dimensional net-like body having a low-mesh attachment are produced by pressing and integrating the non-woven fabric from the side of the non-woven fabric for the water-permeable layer with press rolls. The low mesh area corresponds to the portion where the hole of the spinning nozzle is blocked. The non-woven fabric for the water-permeable layer and the three-dimensional net-like body can be welded and integrated by cooling and solidifying the continuous filaments at the time of press-bonding by pressing rolls. If necessary, a pigment masterbatch such as a black pigment masterbatch may be blended with the resin constituting the three-dimensional network. As the nonwoven fabric for the water-permeable layer, those described above can be used. The width of the portion of the spinning nozzle that closes the hole may be 50 mm or more, 80 mm or more, or 100 mm or more. The upper limit of the width of the portion of the spinning nozzle that closes the hole may be, for example, 400 mm or less, 300 mm or less, or 200 mm or less. The width of the portion of the spinning nozzle that closes the hole may be 0.20 or less, 0.15 or less, or 0.10 or less of the entire width of the spinning nozzle. The width of the portion of the spinning nozzle that closes the hole may be 0.025 or more, 0.040 or more, or 0.050 or more of the entire width of the spinning nozzle. The overall width of the spinning nozzle refers to the distance between the holes at the ends of the spinning nozzle.

Next, in the laminated body obtained above, an attachment piece is superimposed on the surface of the low mesh band on the side opposite to the water permeable layer of the three-dimensional mesh, and the attachment piece and the water permeable layer are joined so that the length of the waterproof sheet for tunnels is at the joint. Join so that it exists parallel to the direction. As mounting pieces, those described above can be used. The bonding can be done so that the bonding line is straight. The number of joint lines may be one, or two or more substantially parallel to each other. When the joining method is suturing, it is recommended to use a sewing machine or the like.

After a hot-melt adhesive is attached to the surface of the resin sheet for the impermeable layer in dots at predetermined intervals, the nonwoven fabric for the impermeable layer of the laminate obtained above is attached to the resin sheet for the impermeable layer. By laminating and integrating, a waterproof sheet for tunnels can be obtained. Although the hot-melt adhesive is not particularly limited, for example, a hot-melt adhesive made of ethylene-vinyl acetate copolymer or the like can be used from the viewpoint of enhancing adhesiveness.

The waterproof sheet for tunnels of the present invention can discharge spring water that flows out from the primary lining concrete on the natural ground side during tunnel construction. The waterproof sheet for tunnel is used so that the mounting piece is on the primary lining concrete side, the impermeable layer is on the secondary lining concrete side, and the longitudinal direction is along the circumferential direction of the tunnel cross section. The waterproof sheet for tunnels has the role of discharging spring water that flows out from the primary lining concrete surface to the outside and preventing the spring water from flowing out to the secondary lining concrete side.

EXAMPLES The present invention will be described in more detail below using examples. In addition, the present invention is not limited to the following examples.

The measurement methods used in Examples and Comparative Examples are as follows.

(Metsuke)
The fabric weight of the nonwoven fabric was measured according to JIS L 1096 (2010) 8.3.
The basis weight of the resin sheet was measured according to JIS A 6008 (2006) 8.4.
In the three-dimensional net-like body, the weight per unit area with low mesh was measured according to JIS L 1096 (2010) 8.3.
In the three-dimensional net-like body, the overall basis weight (weight at other locations) was determined by dividing the width into three equal parts and measuring the basis weight at locations other than the central portion according to JIS L 1096 (2010) 8.3.
(Workability of mounting piece)
The attaching piece and the nonwoven fabric for the water-permeable layer were sewn together through the three-dimensional mesh until the length in the longitudinal direction became 60 m.
(thickness)
The thickness of the nonwoven fabric and the thickness of the three-dimensional mesh were measured under a load of 1.96 kPa according to JIS L 1096 (2010) 8.4.
The thickness of the resin sheet was measured according to JIS A 6008 (2006) 8.2. That is, the thickness was measured according to JIS K 6250 (2019) 10.2 (A method) for the measurement points described in this method.

[material]
Materials and equipment used in Examples were prepared as follows.
(permeable layer)
The following nonwoven fabric was prepared for the water permeable layer.
Spunbond nonwoven fabric made of polyethylene terephthalate (basis weight: about 130 g/m ² , thickness: 1.3 to 1.4 mm, fineness: 3.3 dtex (fiber diameter: about 18 μm), manufactured by Toyobo Co., Ltd., trade name: "Bolance 4131N")
(impermeable layer)
The following resin sheets were prepared as the impermeable layer.
Ethylene-vinyl acetate copolymer A (vinyl acetate content 14% by mass, manufactured by Mitsui-Dow Polychemicals, trade name "EV560"), ethylene-vinyl acetate copolymer B (vinyl acetate content 28% by mass, Mitsui-Dow Polychemicals Co., Ltd., trade name "EV260") and linear low-density polyethylene (Prime Polymer Co., Ltd., trade name "SP2040") are mixed at a mass ratio of 25:50:25 and subjected to the T-die method. A resin sheet (basis weight: about 800 g/m ² , thickness: 0.85 mm) that was melt-extruded and molded into a film and cooled
(resin)
The following resins were prepared for forming the three-dimensional mesh.
Resin (spinning nozzle) obtained by mixing 100 parts by mass of polypropylene resin (manufactured by Japan Polypropylene Corporation, trade name "SA01A") with a black pigment masterbatch
The following spinning nozzles were prepared for use in producing a three-dimensional mesh.
A nozzle that is long in the width direction and has holes with a hole diameter of 1.0 mm arranged in the width direction with a distance between adjacent holes of 5.0 mm and a distance between the outermost holes of 2000 mm (mounting piece )
The following sheets were prepared as mounting pieces.
Woven fabric: 120 g/m ² basis weight, 0.20 mm thickness, 30 cm in width direction, made of nylon fiber

[Comparative Example 1]
(Manufacturing of three-dimensional mesh)
A non-woven fabric for a water-permeable layer is placed on a conveying belt, the resin is heated and melted, discharged from the spinning nozzle, and the belt is moved in the machine direction while the continuous filament is suspended on a mold with a depth of 5.0 mm. Before the solidification of the continuous filaments, the nonwoven fabric for the water-permeable layer is laminated on the three-dimensional network, and the nonwoven fabric for the water-permeable layer and the three-dimensional structure are integrated by press rolls from the side of the nonwoven fabric for the water-permeable layer. A laminate of mesh was produced. The resulting three-dimensional net-like body had a filament diameter of about 1.0 mm, a thickness of 5.0 mm, an overall basis weight of about 300 g/m ² , an overall width of about 2000 mm, and no low mesh area. . The nonwoven fabric for the permeable layer and the three-dimensional net-like body were bonded and integrated by cooling and solidifying the continuous filaments.
(Installation of mounting piece)
Regarding the laminate of the non-woven fabric and the three-dimensional mesh, a sheet serving as an attachment piece was placed on the three-dimensional mesh, and the attachment piece and the non-woven fabric were sewn together through the three-dimensional mesh by a sewing machine. The joining point (sewing point) was the substantially central portion in the width direction of the laminate, and was sewn linearly along the longitudinal direction (machine direction). The joining (stitching) was performed by two sewing lines substantially parallel to each other, and the width of the joint (stitching point), ie the distance between the two sewing lines, was about 20 mm.
(Lamination with impermeable layer)
A hot-melt adhesive made of ethylene-vinyl acetate copolymer is attached to the surface of the resin sheet for the impervious layer in dots, and then the non-woven fabric side of the laminate is laminated with the resin sheet to integrate the laminate. Comparative Example 1 waterproof sheet was obtained. Adjacent dots of adhesive were spaced 25 cm in the longitudinal direction (machine direction) and 40 cm in the width direction.

[Example 1]
A spinning nozzle for producing a three-dimensional net was subjected to the following processing.
(Processing of spinning nozzle)
Half the number of holes were closed so that the interval between adjacent holes was 10 mm over 100 mm at the center in the width direction of the nozzle, so that the number of continuous filaments discharged from the center was reduced by half.
(Manufacturing of three-dimensional mesh, installation of mounting pieces, lamination with impermeable layer)
A three-dimensional mesh was produced in the same manner as in Comparative Example 1. The three-dimensional net-like body thus obtained had a low mesh area in which the basis weight was lower than the other parts at the central portion in the width direction of the three-dimensional net-like body. The width in the width direction of the low eye area was about 100 mm. The overall basis weight of the three-dimensional net-like body was about 300 g/m ² , the basis weight of the low mesh band was about 150 g/m ² , the overall width was about 2000 mm, the fiber diameter of the filament was about 1.0 mm, and the thickness was about 5.0 mm. .
The installation of the mounting pieces was carried out in the same manner as in Comparative Example 1 at the locations with low meshes, and the lamination with the impermeable layer was carried out in the same manner as in Comparative Example 1 to obtain the waterproof sheet of Example 1.

[Example 2]
A waterproof sheet of Example 2 was obtained in the same manner as in Example 1, except that in processing the spinning nozzle, the width for closing the holes was changed from 100 mm to 120 mm. The width of the low mesh area of the three-dimensional mesh was about 120 mm.

[Example 3]
In the production of the three-dimensional network, except that the overall basis weight of the three-dimensional network was changed from about 300 g/m ² to about 400 g/m ² and the basis weight of the low mesh area was changed from about 150 g/m ² to about 200 g/m ² . A waterproof sheet of Example 3 was obtained in the same manner as in Example 2.

[Example 4]
In the production of the three-dimensional network, except that the overall basis weight of the three-dimensional network was changed from about 300 g/m ² to about 500 g/m ² and the basis weight of the low mesh area was changed from about 150 g/m ² to about 210 g/m ² . A waterproof sheet of Example 4 was obtained in the same manner as in Example 2.

[Example 5]
In the processing of the spinning nozzle, the width to close the holes is changed from 100 mm to 120 mm, and the frequency of closing the holes is changed so that only one hole out of six holes is closed. A waterproof sheet of Example 5 was produced in the same manner as in Example 1, except that the number of filaments was reduced to five-sixths, and the basis weight of the three-dimensional net-like body with low mesh was about 250 g/m ² . got The width of the low mesh area of the three-dimensional mesh was about 120 mm.

[Example 6]
A waterproof sheet of Example 6 was obtained in the same manner as in Example 1, except that in processing the spinning nozzle, the width for blocking the holes was changed from 100 mm to 150 mm. The width of the low mesh area of the three-dimensional mesh was about 150 mm.

The workability of the mounting pieces in Examples and Comparative Examples was evaluated as described above, and the results are shown in Table 1 below.

In the waterproof sheets of Examples 1 to 6, the three-dimensional net-like body has a low mesh area, and the attachment pieces are sewn together on the surface of the low mesh area, so thread breakage hardly occurs and workability is improved. was good.
In Comparative Example 1, in which the three-dimensional net-like body did not have the low mesh attachment, thread breakage occurred four times when the attachment pieces were sewn continuously for 60 m in the longitudinal direction, indicating poor workability.

INDUSTRIAL APPLICABILITY The waterproof sheet for tunnels of the present invention can be suitably used as a waterproof sheet that discharges spring water flowing out from the primary lining concrete surface to the outside and prevents the spring water from flowing out to the secondary lining concrete side.

REFERENCE SIGNS LIST 1 waterproof sheet for tunnel 2 impervious layer 3 permeable layer 4 three-dimensional mesh 5 attachment piece 6 adhesive 7 joint line (joint)
LD Longitudinal direction WD Width direction

Claims (11)

A waterproof sheet for tunnels, comprising an impermeable layer, a permeable layer, a three-dimensional mesh, and attachment pieces to be attached to the primary lining concrete surface of the tunnel,
The impermeable layer, the permeable layer and the three-dimensional mesh are laminated in the order of the impermeable layer, the permeable layer and the three-dimensional mesh,
The three-dimensional net-like body has a low mesh area that is lower in basis weight than other parts,
The attachment piece is arranged on the surface of the three-dimensional mesh body opposite to the permeable layer,
The attachment piece and the water permeable layer are joined with the three-dimensional mesh sandwiched therebetween, and the joint is parallel to the longitudinal direction of the tunnel waterproof sheet,
The waterproof sheet for tunnels, wherein the portion of the three-dimensional net-like body sandwiched between the joints is located at the low mesh area. The waterproof sheet for tunnels according to claim 1, wherein the three-dimensional net-like body has a total basis weight of 200 g/m2 ^or more. The waterproof sheet for tunnels according to claim 1 or 2, wherein in the three-dimensional net-like body, the ratio of the basis weight of the low mesh area to the overall basis weight is 0.30 or more and 0.90 or less. The waterproof sheet for tunnels according to any one of Claims 1 to 3, wherein the width of the low eye area is 50 mm or more. The waterproof sheet for tunnels according to any one of claims 1 to 4, wherein the ratio of the width of said low mesh area to the overall width of said three-dimensional net-like body is 0.20 or less. The waterproof sheet for tunnels according to any one of claims 1 to 5, wherein the low mesh band has a basis weight of 80 g/m ² or more and 250 g/m ^{2 or} less. A method for manufacturing a waterproof sheet for tunnels, which includes a water shield layer, a water permeable layer, a three-dimensional mesh, and attachment pieces to be attached to the primary lining concrete surface of the tunnel,
A step of providing a three-dimensional net-like body with a low mesh area having a lower basis weight than other parts by manufacturing the three-dimensional net-like body using a spinning nozzle in a state where a part of the hole existing in the center in the width direction is blocked;
In the laminated body of the three-dimensional net-like body and the permeable layer, an attachment piece is superimposed on the surface of the low-grained accessory of the three-dimensional net-like body opposite to the permeable layer, and the attachment piece and the permeable layer are joined at a waterproofing for a tunnel. A method for manufacturing a waterproof sheet for tunnels, comprising a step of joining sheets so as to exist parallel to the longitudinal direction of the sheets, and a step of laminating and integrating a water impermeable layer on the surface of the water permeable layer. 8. The method for manufacturing a waterproof sheet for tunnels according to claim 7, wherein in said three-dimensional net-like body, the ratio of the basis weight of said low mesh area to the total basis weight is 0.30 or more and 0.90 or less. 9. The method for manufacturing a waterproof sheet for tunnels according to claim 7 or 8, wherein the width of said low mesh band is 50 mm or more. The method for manufacturing a waterproof sheet for tunnels according to any one of claims 7 to 9, wherein the ratio of the width of said low mesh area to the overall width of said three-dimensional net-like body is 0.20 or less. The method for producing a waterproof sheet for tunnels according to any one of claims 7 to 10, wherein the low mesh band has a basis weight of 80 g/m ² or more and 250 g/m ² or less.

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