Waterproof sheet for tunnel and method for manufacturing the same

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

[0001] The present invention relates to a tunnel waterproof sheet for discharging water gushing out from the primary lining concrete on the ground side in tunnel construction to the outside and a method for manufacturing the same.

Background Art

[0002] As one of the tunnel construction methods in mountainous areas, the New Austrian Tunneling Method (hereinafter also referred to as NATM) is known. In NATM, usually, after excavation, concrete is sprayed onto the tunnel excavation wall surface (primary lining concrete), rock bolts are inserted into the ground, and then, after the internal displacement is stabilized, a waterproof sheet is constructed on the primary lining concrete surface, and then secondary lining concrete is placed.

[0003] The waterproof sheet plays a role of discharging the water gushing out from the primary lining concrete surface to the outside and preventing the water from flowing out to the secondary lining concrete side. As such a waterproof sheet, conventionally, for example, as described in Patent Document 1, an integrated sheet composed of an impermeable sheet made of synthetic resin and a permeable mat made of non-woven fabric has been used. In recent years, in order to improve the drainage performance, for example, as described in Patent Document 2, a sheet provided with a water-conducting layer composed of a three-dimensional network structure has been proposed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] On one hand, when constructing a waterproof sheet, in order to suppress the sagging of the middle part of the sheet, for example, as described in Patent Document 1, by providing attachment pieces for intermediate fixing, the middle part of the sheet is fixed to the primary lining concrete surface. However, in the case of a waterproof sheet including a three-dimensional reticulated body as described in Patent Document 2, it is difficult to process the attachment pieces for intermediate fixing. When joining the attachment pieces for intermediate fixing by sewing, the needle may come into contact with the filaments constituting the three-dimensional reticulated body during sewing, and there may be frequent needle breakage and thread breakage.

[0006] In order to solve the above conventional problems, the present invention provides a waterproof sheet for a tunnel including a three-dimensional reticulated body and having good workability of attachment pieces attached to the primary lining concrete surface of the tunnel, and a method for manufacturing the same.

Means for Solving the Problems

[0007] The present invention relates to a waterproof sheet for a tunnel including a water barrier layer, a water permeable layer, a three-dimensional reticulated body, and attachment pieces attached to the primary lining concrete surface of the tunnel. The water barrier layer, the water permeable layer, and the three-dimensional reticulated body are laminated in the order of the water barrier layer, the water permeable layer, and the three-dimensional reticulated body. The three-dimensional reticulated body has a low basis weight band with a lower basis weight in the central part in the width direction than in other places. The attachment pieces are arranged on the surface of the three-dimensional reticulated body on the side opposite to the water permeable layer. The attachment pieces and the water permeable layer are joined with the three-dimensional reticulated body sandwiched therebetween. The joining location exists parallel to the longitudinal direction of the waterproof sheet for a tunnel. The portion of the three-dimensional reticulated body sandwiched by the joining location is located in the low basis weight band.

[0008] The present invention also relates to a method for manufacturing a waterproof sheet for a tunnel, which includes a water-blocking layer, a water-permeable layer, a three-dimensional reticulated body, and an attachment piece to be attached to the primary lining concrete surface of the tunnel. The method includes a step of providing a low basis weight band with a lower basis weight than other locations on the three-dimensional reticulated body by manufacturing the three-dimensional reticulated body using a spinning nozzle in a state where a part of the holes existing in the central portion in the width direction is blocked. In the laminate of the three-dimensional reticulated body and the water-permeable layer, an attachment piece is overlapped on the surface of the low basis weight band on the side opposite to the water-permeable layer of the three-dimensional reticulated body, and the attachment piece and the water-permeable layer are joined so that the joining portion exists parallel to the longitudinal direction of the waterproof sheet for the tunnel. The method further includes a step of laminating and integrating the water-blocking layer on the surface of the water-permeable layer.

Effects of the Invention

[0009] The present invention can provide a waterproof sheet for a tunnel including a three-dimensional reticulated body, and a method for manufacturing the same, which has good processability of an attachment piece to be attached to the primary lining concrete surface of the tunnel. According to the manufacturing method of the present invention, an attachment piece to be attached to the primary lining concrete surface of the tunnel can be provided with good processability on the waterproof sheet for the tunnel including the three-dimensional reticulated body.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] The inventor has repeatedly studied to improve the workability in the case of providing an attachment piece for attaching to the primary lining concrete surface of a tunnel in a waterproof sheet for a tunnel having a three-dimensional reticulated body (hereinafter, also simply referred to as a reticulated body). As a result, a low basis weight band having a lower basis weight (mass per unit area) than other portions is provided at the central portion in the width direction of the three-dimensional reticulated body, and when the water shielding layer and the water permeable layer are joined with the three-dimensional reticulated body interposed therebetween, the portion of the three-dimensional reticulated body sandwiched by the joining portion is positioned in the low basis weight band, so that almost no process defects occur in the joining process and the workability is improved.

[0012] The waterproof sheet for a tunnel includes a water shielding layer, a water permeable layer, a three-dimensional reticulated body, and an attachment piece (hereinafter, simply referred to as an "attachment piece") for attaching to the primary lining concrete surface of the tunnel. FIG. 1 is a schematic exploded perspective view of a waterproof sheet for a tunnel according to an example of the present invention, and FIG. 2 is the same schematic perspective view. As shown in FIG. 1, in the waterproof sheet 1 for a tunnel, the water shielding layer 2, the water permeable layer 3, and the three-dimensional reticulated body 4 are laminated in this order, and the attachment piece 5 is disposed on the surface of the three-dimensional reticulated body 4 opposite to the water permeable layer 3. The water shielding layer 2 is dot-bonded to the water permeable layer 3 with an adhesive 6 disposed at a predetermined interval. The attachment piece 5 and the water permeable layer 3 are joined 7 with the three-dimensional reticulated body 4 interposed therebetween. In FIGS. 1 and 2, the joining 7 is shown as sewing with a sewing machine or the like. In FIGS. 1 and 2, LD indicates the longitudinal direction, and WD indicates the width direction. LD and WD are orthogonal to each other.

[0013] In FIG. 1, the joining 7 (sewing) is performed with two joining lines (sewing lines) substantially parallel to each other, but it may be performed with one joining line (sewing line), or may be performed with two or more joining lines (sewing lines) substantially parallel to each other. From the viewpoints of simplicity and productivity, the joining 7 (sewing) is preferably performed with two joining lines (sewing lines) substantially parallel to each other.

[0014] <Water shielding layer> The water barrier layer serves to prevent the inflow of spring water to the concrete side. For example, in tunnel construction, by installing a waterproof sheet for tunnels on the primary lining concrete side, it is ensured that the spring water generated from the ground side does not flow out beyond the waterproof sheet to the secondary lining concrete side. If spring water migrates to the secondary lining concrete side, cracks are likely to occur in the secondary lining concrete, and there is a risk of the concrete collapsing.

[0015] The water barrier layer may be composed of a sheet that does not allow water to permeate and is not particularly limited. For example, the water barrier layer can be composed of a resin sheet. The resin sheet may contain 20% by mass or more and 90% by mass or less of ethylene-vinyl acetate copolymer and may contain 10% by mass or more and 90% by mass or less of polyethylene. When the content of ethylene-vinyl acetate copolymer in the resin sheet is 20% by mass or more, it has good water barrier properties due to the resin properties of ethylene-vinyl acetate copolymer. Furthermore, due to the resin properties of ethylene-vinyl acetate copolymer, for example, even in a low-temperature environment of 10°C or lower, the waterproof sheet does not harden, and the followability to the construction surface is maintained. From the perspective of obtaining such effects more significantly, it is preferable that the resin sheet contains 40% by mass or more of ethylene-vinyl acetate copolymer, more preferably 60% by mass or more, and particularly preferably 70% by mass or more. When the content of polyethylene in the resin sheet is 10% by mass or more, a resin sheet excellent in adhesion to the non-woven fabric constituting the water permeable layer can be obtained. Also, from the perspective of not reducing the flexibility and tensile strength of the water barrier layer, it is preferable that the resin sheet contains 60% by mass or less of polyethylene, more preferably 40% by mass or less, and particularly preferably 30% by mass or less.

[0016] The above 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 excellent in 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, there is little chance that the water barrier layers stick together and integrate (block). From the viewpoint of obtaining such an effect more remarkably, the vinyl acetate content is more preferably 5% by mass or more and 40% by mass or less, and even more preferably 10% by mass or more and 30% by mass or less.

[0017] The above polyethylene can be selected and used from one or more of the group consisting of high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. When high-density polyethylene is used, a resin sheet excellent in impact resistance can be obtained due to its resin properties. Further, when low-density polyethylene is used, a resin sheet excellent in heat weldability can be obtained due to its resin properties. Among them, polyethylene is preferably linear low-density polyethylene. A resin sheet containing linear low-density polyethylene has particularly excellent tensile strength. When the resin sheet is excellent in tensile strength, the water barrier layer is less likely to break.

[0018] The above polyethylene preferably 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) of 1 g / 10 min or more and 10 g / 10 min or less. When the MFR of polyethylene is 1 g / 10 min or more, it is easy to produce the water barrier sheet. When the MFR of polyethylene is 10 g / 10 min or less, there is little chance that the strength of the water barrier sheet will decrease. From the viewpoint of obtaining such an effect more remarkably, the MFR of polyethylene is more preferably 1.5 g / 10 min or more and 7 g / 10 min or less.

[0019] In addition to the ethylene-vinyl acetate copolymer and polyethylene, the resin sheet may contain other resins. The content of other resins is preferably 30% by mass or less, more preferably 10% by mass or less, based on the total mass of the resin sheet. The other resins are not particularly limited, and for example, polyolefin resins such as polypropylene, copolymers of propylene and olefins other than propylene, polybutene-1, copolymers of ethylene and olefins other than ethylene different from the above-mentioned polyethylene, and ethylene-vinyl alcohol copolymers can be used. Further, the resin sheet may contain antioxidants, heat stabilizers, etc. in an amount of 10% by mass or less, based on the total mass of the water barrier sheet, if necessary.

[0020] 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 water barrier layer is 0.10 mm or more and 3.0 mm or less, it becomes a waterproof sheet for tunnels with excellent handleability during construction. The thickness of the resin sheet is measured in accordance with JIS A 6008(2006) 8.2. That is, the thickness is measured in accordance with JIS K 6250(2019) 10.2 (Method A) for the measurement locations described in this method.

[0021] The resin sheet is not particularly limited, but from the viewpoint of handleability during construction, the basis weight (mass per unit area) measured in accordance with JIS A 6008(2006) 8.4 is 2 1000 g / m 2 or more and preferably 2 900 g / m 2 or less, more preferably

[0022] The resin sheet preferably has a tensile strength (tensile strength at break) measured in accordance with JIS K 6251(2017) of 2 10 N / mm 2 or more, more preferably 2If it is as described above, the resin sheet is difficult 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 tested according to Test Piece Type 5 of JIS K 7127 (1999).

[0023] The elongation rate (elongation at break) measured for the above resin sheet in accordance with JIS K 6251 (2017) is preferably 500% or more, and more preferably 600% or more. When the elongation rate is 500% or more, it becomes easier to construct the waterproof sheet for tunnels 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 the elongation rate is the same as the test piece used for measuring the tensile strength described above.

[0024] The tear strength measured for the above resin sheet in accordance with JIS K 6252 (2015) 4.3 Test Method B - Procedure (a): Method using a cutless angled test piece is preferably 400 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.

[0025] The above resin sheet can be produced, for example, by melting a resin composition containing an ethylene-vinyl acetate copolymer and polyethylene, extruding it from a T-die, adjusting the thickness between metal rolls, and forming it into a sheet of a predetermined thickness. At this time, the ethylene-vinyl acetate copolymer and polyethylene may be premixed and made into a masterbatch. Further, additives such as a hindered phenol-based antioxidant, a phosphorus-based heat stabilizer, and a hydroxyamine-based heat stabilizer may be added as necessary. Also, the water barrier sheet may be subjected to a stretching treatment as necessary.

[0026] <Water-permeable layer> The permeable layer can be composed of a non-woven fabric. The non-woven fabric is not particularly limited, and for example, either a long fiber non-woven fabric or a short fiber non-woven fabric may be used. Examples of the long fiber non-woven fabric include a spunbond non-woven fabric and a meltblown non-woven fabric. Examples of the short fiber non-woven fabric include a needle-punched non-woven fabric, a spunlace non-woven fabric, and a thermal bond non-woven fabric. Also, a non-woven fabric obtained by binder-treating a long fiber non-woven fabric or a short fiber non-woven fabric with a binder resin may be used.

[0027] The fibers constituting the non-woven fabric are not particularly limited, and examples thereof include fibers made of synthetic resins such as polyolefin resins such as polyethylene, polypropylene, and polybutene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, and polyamide resins such as nylon 6 and nylon 66. Among them, the fibers constituting the non-woven fabric preferably contain a polyester resin from the viewpoint of excellent non-woven fabric strength and bulkiness.

[0028] The fibers constituting the non-woven fabric are not particularly limited, and the single fiber fineness may be 1 dtex or more and 100 dtex or less, may be 2 dtex or more and 80 dtex or less, or may be 4 dtex or more and 60 dtex or less. When the fineness is within the above-described range, the tensile strength and tear strength of the non-woven fabric can be increased.

[0029] The non-woven fabric preferably has a thickness of 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 or more and 3.0 mm or less. When the thickness of the non-woven fabric is 0.50 mm or more, the effect of preventing damage to the water barrier sheet by protrusions is higher. When the thickness of the non-woven fabric is 20 mm or less, it is difficult for the non-woven fabric to break or peel in the thickness direction. The thickness of the non-woven fabric is measured in a state where a load of 1.96 kPa is applied in accordance with JIS L 1096(2010)8.4.

[0030] The non-woven fabric has a basis weight (mass per unit area) of 80 g / m 2250 g / m or less is preferred, more preferably 120 g / m or more and 200 g / m or less. The basis weight of the nonwoven fabric is preferably 80 g / m or more. When the basis weight of the nonwoven fabric is 80 g / m or more, the tensile strength is high and it is difficult to break. Also, when the basis weight of the nonwoven fabric is 250 g / m or less, it does not become too heavy and construction is easy. The basis weight of the nonwoven fabric is measured in accordance with JIS L 1096 (2010) 8.3. 2 250 g / m or less is preferred, more preferably 120 g / m or more and 200 g / m or less. The basis weight of the nonwoven fabric is preferably 80 g / m or more. When the basis weight of the nonwoven fabric is 80 g / m or more, the tensile strength is high and it is difficult to break. Also, when the basis weight of the nonwoven fabric is 250 g / m or less, it does not become too heavy and construction is easy. The basis weight of the nonwoven fabric is measured in accordance with JIS L 1096 (2010) 8.3. 2 250 g / m or less is preferred, more preferably 120 g / m or more and 200 g / m or less. The basis weight of the nonwoven fabric is preferably 80 g / m or more. When the basis weight of the nonwoven fabric is 80 g / m or more, the tensile strength is high and it is difficult to break. Also, when the basis weight of the nonwoven fabric is 250 g / m or less, it does not become too heavy and construction is easy. The basis weight of the nonwoven fabric is measured in accordance with JIS L 1096 (2010) 8.3. 2 250 g / m or less is preferred, more preferably 120 g / m or more and 200 g / m or less. The basis weight of the nonwoven fabric is preferably 80 g / m or more. When the basis weight of the nonwoven fabric is 80 g / m or more, the tensile strength is high and it is difficult to break. Also, when the basis weight of the nonwoven fabric is 250 g / m or less, it does not become too heavy and construction is easy. The basis weight of the nonwoven fabric is measured in accordance with JIS L 1096 (2010) 8.3. 2 250 g / m or less is preferred, more preferably 120 g / m or more and 200 g / m or less. The basis weight of the nonwoven fabric is preferably 80 g / m or more. When the basis weight of the nonwoven fabric is 80 g / m or more, the tensile strength is high and it is difficult to break. Also, when the basis weight of the nonwoven fabric is 250 g / m or less, it does not become too heavy and construction is easy. The basis weight of the nonwoven fabric is measured in accordance with JIS L 1096 (2010) 8.3. 2 250 g / m or less is preferred, more preferably 120 g / m or more and 200 g / m or less. The basis weight of the nonwoven fabric is preferably 80 g / m or more. When the basis weight of the nonwoven fabric is 80 g / m or more, the tensile strength is high and it is difficult to break. Also, when the basis weight of the nonwoven fabric is 250 g / m or less, it does not become too heavy and construction is easy. The basis weight of the nonwoven fabric is measured in accordance with JIS L 1096 (2010) 8.3.

[0031] The above nonwoven fabric is not particularly limited, but the tensile strength measured in accordance with JIS L 1096 (2010) 8.14 Method A (strip method) is preferably 200 N / 5 cm or more, more preferably 250 N / 5 cm or more. When the tensile strength is 200 N / 5 cm or more, the nonwoven fabric is difficult to break. The preferred upper limit of the tensile strength is 1000 N / 5 cm or less.

[0032] The above nonwoven fabric is not particularly limited, but the elongation rate measured in accordance with JIS L 1096 (2010) 8.14 Method A (strip method) is preferably 20% or more, more preferably 50% or more. When the elongation rate is 20% or more, it becomes easier to follow the elongation of the resin sheet constituting the water barrier 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 becomes difficult for water gushing and sediment to accumulate between the water permeable layer and the three-dimensional network body, and it becomes easier for the space between the water permeable layer and the water barrier layer to function as a water conduction path, and a large amount of gushing water can be drained.

[0033] The above nonwoven fabric is not particularly limited, but the tear strength measured in accordance with JIS L 1096 (2010) 8.17 Method A-1 (single tongue method) is preferably 50 N or more, more preferably 60 N or more. When the tear strength is 50 N or more, the nonwoven fabric is difficult to tear. The preferred upper limit of the tear strength is 150 N or less.

[0034] The non-woven fabric may be composed of one type of fiber or may be a non-woven fabric in which two or more fibers are mixed. Also, any of the non-woven fabrics may be a single-layer non-woven fabric composed of one layer of web, or may be a laminated non-woven fabric in which two or more layers of webs are laminated. Further, the non-woven fabric may be composed of fibers made of a single-component resin, or may be composed of composite fibers using two or more resins.

[0035] <Three-dimensional network structure> In the present invention, the three-dimensional network structure functions as a water conduit for draining spring water or the like to the outside. The water conduit composed of the three-dimensional network structure can drain a larger amount of spring water because the water conduit remains a certain thickness even when pressure is applied to the waterproof sheet for tunnels due to the placement of concrete or the self-weight of soil. For example, when the waterproof sheet for tunnels is arranged between the primary lining concrete and the secondary lining concrete of the tunnel such that the water barrier layer is on the secondary lining concrete side, spring water or the like generated from the primary lining concrete side passes through the voids of the three-dimensional network structure in addition to the space between the water-permeable layer and the water barrier layer and is discharged to the outside.

[0036] The three-dimensional network structure is formed by a plurality of continuous filaments with a thickness (diameter) of 0.1 mm or more and 10 mm or less intersecting irregularly in the horizontal direction and / or the thickness direction. In the three-dimensional network structure, since the filaments are continuous, there are fewer filament tips compared to the case where the filaments are discontinuous, and the filament tips do not damage or rarely damage the water barrier sheet. The thickness of the continuous filament is preferably 0.3 mm or more and 5.0 mm or less, and 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 less likely to break. Also, when the thickness of the continuous filament is 10 mm or less, the adhesion intersections between the continuous filaments or between the continuous filaments and the non-woven fabric do not become too large, and the three-dimensional network structure forms appropriate voids. Note that the thickness of the continuous filament is measured by measuring the diameters at any 100 locations of the continuous filament, and the average value is taken as the thickness of the continuous filament.

[0037] The cross-sectional shape of the continuous filament is not particularly limited and may be any shape such as circular, elliptical, triangular, quadrangular, polygonal, Y-shaped, cross-shaped, etc. When the filament cross-section is other than circular, the thickness of the continuous filament is defined as the circular diameter when measuring the filament cross-sectional area and converting it to a circle with the same area as this cross-sectional area.

[0038] The resin constituting the continuous filament is not particularly limited, but may be a synthetic resin such as polyolefin resin such as polyethylene (including copolymers of ethylene and olefins other than ethylene), polypropylene (including copolymers of propylene and olefins other than propylene), polybutene-1, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyamide resin such as nylon 6, nylon 66, polystyrene (including hydrogenated polystyrene). Among them, it is preferably a polyolefin resin from the viewpoint of excellent alkali resistance and weather resistance. When the continuous filament is composed of a polyolefin resin, it becomes a three-dimensional network body with excellent alkali resistance. For example, even when an alkali solution is generated from the placed concrete, the three-dimensional network body is hardly deteriorated.

[0039] The three-dimensional network body is not particularly limited, but 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 even more preferably 300 g / m 2 or more and 600 g / m 2 or less. When the basis weight is 200 g / m 2 or more, it is easy to form voids serving as water channels, and the drainage performance is improved. When the total basis weight is 1000 g / m 2It is as follows, easy to roll up, not too heavy, and for example, easy to place on a concrete surface. The total areal weight of the three-dimensional network is measured in accordance with JIS L 1096(2010)8.3 by collecting samples from locations other than the low areal weight zone described later. When the three-dimensional network is laminated and integrated with a permeable layer or the like, it may be calculated by subtracting the areal weight of the permeable layer or the like measured in advance from the areal weight of the laminate.

[0040] The three-dimensional network has a low areal weight zone with a lower areal weight than other locations. As described later, by arranging the joint between the permeable layer and the attachment piece so as to sandwich the low areal weight zone of the three-dimensional network, process defects during attachment of the attachment piece are suppressed, and the workability of the attachment piece is improved. From the viewpoint of easily attaching the middle part of the prevention sheet to the primary lining concrete surface of the tunnel, the low areal weight zone is preferably arranged at the center in the width direction of the three-dimensional network and formed to be continuous in the longitudinal direction. In the present invention, other locations mean the two side locations excluding the middle 1 / 3 when the width of the waterproof sheet for tunnels is divided into three equal parts. The areal weight of the low areal weight zone is measured by collecting samples from the low areal weight zone in the same manner as the total areal weight described above. When the low areal weight zone cannot be distinguished from other locations, it is advisable to measure the areal weight within about 50 mm in the width direction centered on the joint. When there are a plurality of joints in the width direction (when there are two or more joint lines), it is advisable to measure the areal weight between the two outermost joints, or the areal weight within about 50 mm in the width direction centered on the midpoint between the two outermost joints. The areal weight of other locations is measured by collecting samples from other locations in the same manner as the total areal weight.

[0041] In the three-dimensional network, the ratio of the areal weight of the low areal weight zone to the total areal weight is preferably 0.30 or more and 0.90 or less, and more preferably 0.40 or more and 0.85 or less. Thereby, the workability of the attachment piece is improved, and high drainage performance can be maintained. Also, in the three-dimensional network, the difference between the total areal weight and the areal weight of the low areal weight zone is preferably 30 g / m 2 or more, and more preferably 60 g / m 2 or more. The upper limit of the difference between the total areal weight and the areal weight of the low areal weight zone is, for example, 500 g / m 2It is preferably as follows, 400 g / m 2 More preferably, it is as follows.

[0042] The basis weight of the low basis weight 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, still more preferably 120 g / m 2 or more and 230 g / m 2 Still more preferably, it is as follows. Thereby, the workability of the attachment piece is improved and high drainage performance can be maintained.

[0043] The width of the above-mentioned low basis weight band is not particularly limited, but is preferably 50 mm or more, more preferably 80 mm or more, and still more preferably 100 mm or more. Thereby, the joint portion between the water permeable layer and the attachment piece is easily arranged so as to sandwich the low basis weight band of the three-dimensional network body. The upper limit of the width of the above-mentioned low basis weight band is preferably, for example, 400 mm or less, more preferably 300 mm or less, and still more preferably 200 mm or less. Thereby, high drainage performance can be maintained.

[0044] The ratio of the width of the low basis weight band to the overall width of the three-dimensional network body is not particularly limited, but is preferably 0.20 or less, more preferably 0.15 or less, and still more preferably 0.10 or less. Thereby, high drainage performance can be maintained. The ratio of the width of the low basis weight band to the overall width of the three-dimensional network body preferably has a lower limit of 0.025 or more, more preferably 0.040 or more, and still more preferably 0.050 or more. Thereby, the joining process of the attachment piece becomes good.

[0045] The three-dimensional reticulated 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 reticulated body is 1.0 mm or more, even if the spring water contains sediment or the like, it is difficult to be clogged and good water permeability can be obtained. Further, when the thickness of the reticulated body is 30 mm or less, it is difficult for the non-woven fabric and the reticulated body to peel off. From the viewpoint of obtaining such an effect more remarkably, the thickness of the three-dimensional reticulated body is preferably 2.0 mm or more and 10 mm or less. Further, the three-dimensional reticulated body may have convex portions or concave portions in the thickness direction. The thickness of the three-dimensional reticulated body is measured in a state where a load of 1.96 kPa is applied in accordance with JIS L 1096 (2010) 8.4. When the three-dimensional reticulated body is laminated and integrated with a water-permeable layer or the like, it may be calculated by subtracting the thickness of the water-permeable layer or the like measured in advance from the thickness of the laminate.

[0046] The three-dimensional reticulated body having a low basis weight band is obtained, for example, by heating and melting the resin constituting the three-dimensional reticulated body to about 200 ° C or more and 350 ° C or less, and extruding the molten resin while randomly rotating it from a spinneret (spinning die) in a state where a part of the holes existing in the central portion in the width direction is blocked, and collecting the continuously intersecting irregular filaments on a collecting plate or a non-woven 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 reticulated body.

[0047] (Mounting piece) The mounting piece is attached to the primary lining concrete surface of the tunnel, fixes the middle of the waterproof sheet for the tunnel to the tunnel, and suppresses the occurrence of sagging. The mounting piece may be in a strip shape continuously formed in the longitudinal direction of the waterproof sheet for the tunnel, or may be square small pieces arranged at regular intervals in the longitudinal direction of the waterproof sheet for the tunnel. The material of the mounting piece is not particularly limited, and may be a non-woven fabric or a woven or knitted fabric. From the viewpoint of strength, a woven fabric can be preferably used. From the viewpoint of handleability, the mounting piece is preferably a continuous arrangement of a strip-shaped woven fabric in the longitudinal direction of the waterproof sheet for the tunnel.

[0048] The attachment piece is joined in a state of sandwiching the water-permeable layer and the three-dimensional net-like body, and the joining portion exists parallel to the longitudinal direction of the waterproof sheet for tunnels. The portion of the three-dimensional net-like body sandwiched by the joining portion is located in the low-grammage band. This suppresses process defects when joining the attachment piece and the water-permeable layer, and improves the workability of the attachment piece. The width of the attachment piece is not particularly limited and can be appropriately set as needed. The width of the attachment piece may be, for example, 200 mm or more and 500 mm or less, may be 250 mm or more and 400 mm or less, or may be 270 mm or more and 350 mm or less. The joining portion may be in the middle of the width direction of the attachment piece or may be unevenly distributed on either side. When unevenly distributed, fixing pins can be driven into the wider side. The joining may be performed with a single joining line or with two or more joining lines that are substantially parallel to each other. From the viewpoints of simplicity and productivity, the joining is preferably performed with two joining lines that are substantially parallel to each other. In addition, when another sheet (such as a non-woven fabric) is inserted between the attachment piece and the three-dimensional net-like body, the attachment piece and the water-permeable layer may be joined through the three-dimensional net-like body and the other sheet.

[0049] Examples of the joining method of the attachment piece include joining by sewing, joining by an adhesive, joining by heat welding, joining by tag pins, etc. Among them, joining by sewing with a sewing machine, etc. is preferable from the viewpoint of workability.

[0050] Joining by sewing can be achieved by sewing the water-permeable layer and the attachment piece with a thread. Since the three-dimensional net-like body existing at the joining portion has a low-grammage band, the needle can easily pass through and it is less likely to break the needle or cut the thread.

[0051] Joining by an adhesive can be achieved by applying an adhesive between the water-permeable layer and the attachment piece. Since the three-dimensional net-like body existing at the joining portion has a low-grammage band, the water-permeable layer and the attachment piece are likely to come into contact with each other, making it easier to perform joining by an adhesive.

[0052] Bonding by heat welding can be achieved by melting and adhering one or both of the water-permeable layer and the mounting piece, which are made of thermoplastic resin, using ultrasonic waves or hot air. Since the three-dimensional network structure present at the bonding location has a low basis weight zone, the water-permeable layer and the mounting piece are likely to come into contact with each other, making it easier to perform bonding by heat welding.

[0053] Bonding by tag pins is used for tagging clothing items and the like. By using tag pins having T-shaped or arrow-shaped fixing parts at both ends and using a tag gun, the water-permeable layer and the mounting piece can be joined. Since the three-dimensional network structure present at the bonding location has a low basis weight zone, the needle of the tag gun can easily penetrate, making it easier to perform bonding by tag pins.

[0054] The non-woven fabric and the three-dimensional network structure constituting the water-permeable layer may be laminated and integrated via an adhesive, or may be laminated and integrated by the components constituting the continuous filaments. It is preferable that the non-woven fabric and the three-dimensional network structure constituting the water-permeable layer are integrated by the components constituting the continuous filaments, and it is more preferable that they are integrated by fusing the components constituting the continuous filaments. When the non-woven fabric constituting the water-permeable layer and the network structure are integrated by the components constituting the continuous filaments, it becomes difficult for the water-permeable layer and the network structure to peel off. Also, at the bonding points, by forming the continuous filaments into a film, the water-permeable layer and the network structure can be integrated more firmly.

[0055] The non-woven fabric constituting the water-permeable layer and the resin sheet constituting the water-blocking layer may be adhered via an adhesive, or may be adhered by heat welding with the components constituting the non-woven fabric or the resin sheet. It is preferable that the non-woven fabric constituting the water-permeable layer and the resin sheet constituting the water-blocking layer are adhered by a hot melt adhesive or heat welding.

[0056] The nonwoven fabric constituting the water-permeable layer and the resin sheet constituting the water-blocking layer are preferably adhesively bonded in dots or lines. When the nonwoven fabric constituting the water-permeable layer and the resin sheet constituting the water-blocking layer are adhesively bonded in dots or lines, the space between the nonwoven fabric and the resin sheet easily functions as a water conduction path, and a large amount of spring water can be drained. When a large amount of spring water occurs, a space is formed in the non-bonded portion between the nonwoven fabric and the resin sheet due to the water pressure, and this space becomes a water conduction path, enabling efficient drainage.

[0057] The adhesion interval of the dot adhesion or line adhesion is preferably 2 cm or more and 70 cm or less. Here, the adhesion interval means, in the case of dot adhesion, the distance between two adjacent adhesion points, and in the case of line adhesion, the distance to the nearest other adhesion line in a direction perpendicular to the adhered line portion. When the adhesion interval is 2 cm or more, a space is easily formed in the non-bonded portion, and when the adhesion interval is 70 cm or less, it is difficult for the nonwoven fabric and the water-blocking sheet to shift during construction, facilitating construction.

[0058] Among them, the nonwoven fabric constituting the water-permeable layer and the resin sheet constituting the water-blocking layer are preferably adhesively bonded in dots 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, it is difficult for the water-permeable layer and the water-blocking layer to peel off, and an excellent water conduction path can be formed between the water-permeable layer and the water-blocking layer.

[0059] The waterproof sheet for tunnels preferably has a basis weight of 2.0 kg / m 2 or less, and more preferably 1.5 kg / m 2 or less. When the basis weight of the waterproof sheet for tunnels is 2.0 kg / m 2 or less, the waterproof sheet for tunnels becomes lighter and construction becomes easier. For example, it is also easy to construct when stretching it on the tunnel ceiling part etc. Although not particularly limited, the preferable lower limit is 0.50 kg / m 2 or more.

[0060] The waterproof sheet for tunnels is not particularly limited, but can be produced, for example, as follows. By manufacturing using a spinning nozzle in which a part of the holes existing in the central portion in the width direction of the three-dimensional network body is blocked, a low basis weight band having a lower basis weight than other portions is provided in the three-dimensional network body. In a laminate of the three-dimensional network body and the water-permeable layer, attachment pieces are overlapped on the surface of the low basis weight band on the side opposite to the water-permeable layer of the three-dimensional network body, and the attachment pieces and the water-permeable layer are joined so that the joining portion exists parallel to the longitudinal direction of the waterproof sheet for tunnels, and a water-blocking layer is laminated and integrated on the surface of the water-permeable layer, whereby a waterproof sheet for tunnels can be obtained.

[0061] First, the resin constituting the three-dimensional network body is heated and melted to about 200°C or more and 350°C or less, and the molten resin is extruded while being randomly rotated circumferentially from a spinning nozzle (spinning die) in a state where a part of the holes existing in the central portion in the width direction is blocked, and the continuously intersecting filaments are collected on a die for obtaining a desired thickness to form a three-dimensional network body. Before the continuous filaments are solidified, a nonwoven fabric for the water-permeable layer is laminated on the three-dimensional network body, and a laminate of the nonwoven fabric for the water-permeable layer and the three-dimensional network body having a low basis weight band is produced while being pressure-bonded and integrated from the side of the nonwoven fabric for the water-permeable layer with a pressing roll. The low basis weight band corresponds to the portion where the holes of the spinning nozzle are blocked. The nonwoven fabric for the water-permeable layer and the three-dimensional network body can be welded and integrated by the cooling and solidification of the continuous filaments during pressure bonding by the pressing roll. If necessary, a pigment masterbatch such as a black pigment masterbatch may be blended into the resin constituting the three-dimensional network body. As the nonwoven fabric for the water-permeable layer, those described above can be used. The width of the portion where the holes of the spinning nozzle are blocked may be 50 mm or more, may be 80 mm or more, and may be 100 mm or more. The width of the portion where the holes of the spinning nozzle are blocked may have an upper limit of, for example, 400 mm or less, may be 300 mm or less, and may be 200 mm or less. Also, the width of the portion where the holes of the spinning nozzle are blocked may be 0.20 or less of the overall width of the spinning nozzle, may be 0.15 or less, and may be 0.10 or less. The width of the portion where the holes of the spinning nozzle are blocked may be 0.025 or more of the overall width of the spinning nozzle, may be 0.040 or more, and may be 0.050 or more. Note that the overall width of the spinning nozzle refers to the distance between the holes at the outermost ends of the spinning nozzle.

[0062] Next, in the laminate obtained above, attachment pieces are overlapped on the surface of the low basis weight band on the side opposite to the water-permeable layer of the three-dimensional network structure, and the attachment pieces and the water-permeable layer are joined so that the joining portion exists parallel to the longitudinal direction of the waterproof sheet for tunnels. As the attachment pieces, those described above can be used. The joining can be performed so that the joining line is linear. The joining line may be one or two or more that are substantially parallel to each other. When the joining method is sewing, it is advisable to use a sewing machine or the like.

[0063] After a hot melt adhesive is attached in dots at predetermined intervals on the surface of the resin sheet for the water barrier layer, the nonwoven fabric side for the water-permeable layer of the laminate obtained above is bonded to the resin sheet for the water barrier layer and laminated integrally, whereby a waterproof sheet for tunnels can be obtained. The hot melt adhesive is not particularly limited, but for example, from the viewpoint of enhancing adhesiveness, a hot melt adhesive made of an ethylene-vinyl acetate copolymer or the like can be used.

[0064] The waterproof sheet for tunnels of the present invention can discharge the water gushing out from the primary lining concrete on the ground side in tunnel construction to the outside. The waterproof sheet for tunnels is arranged and used such that the attachment pieces are on the primary lining concrete side, the water barrier 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 plays a role of discharging the water gushing out from the primary lining concrete surface to the outside and preventing the water from flowing out to the secondary lining concrete side.

Example

[0065] Hereinafter, the present invention will be described more specifically using examples. Note that the present invention is not limited to the following examples.

[0066] The measurement methods used in the examples and comparative examples are as follows.

[0067] (Basis weight) The basis weight of the nonwoven fabric was measured in accordance with JIS L 1096 (2010) 8.3. The basis weight of the resin sheet was measured in accordance with JIS A 6008 (2006) 8.4. In the three-dimensional network structure, the basis weight of the low basis weight zone was measured in accordance with JIS L 1096 (2010) 8.3. In the three-dimensional network structure, the overall basis weight (basis weight at other locations) was measured in accordance with JIS L 1096 (2010) 8.3 for the basis weight at locations other than the central part when the width was divided into three equal parts. (Workability of the attachment piece) The attachment piece and the nonwoven fabric for the water permeable layer were sewn together through the three-dimensional network structure until the longitudinal dimension reached 60 m. When the number of thread breaks was 1 or less, it was judged that the workability was good. (Thickness) The thickness of the nonwoven fabric and the three-dimensional network structure was measured in accordance with JIS L 1096 (2010) 8.4 under a load of 1.96 kPa. The thickness of the resin sheet was measured in accordance with JIS A 6008 (2006) 8.2. That is, the thickness was measured in accordance with JIS K 6250 (2019) 10.2 (Method A) for the measurement location described in this method.

[0068] [Materials] The following were prepared for the materials and equipment used in the examples. (Water permeable layer) The following nonwoven fabrics were prepared for the water permeable layer. Spunbond nonwoven fabric made of polyethylene terephthalate (basis weight of about 130 g / m 2 , thickness of 1.3 - 1.4 mm, fineness of 3.3 dtex (fiber diameter of about 18 μm), manufactured by Toyobo Co., Ltd., product name "Balance 4131N") (Waterproof layer) The following resin sheets were prepared as the waterproof layer. Ethylene-vinyl acetate copolymer A (vinyl acetate content 14% by mass, manufactured by Mitsui Dow Polychemical Co., Ltd., trade name "EV560"), ethylene-vinyl acetate copolymer B (vinyl acetate content 28% by mass, manufactured by Mitsui Dow Polychemical Co., Ltd., trade name "EV260"), and linear low-density polyethylene (manufactured by Prime Polymer Co., Ltd., trade name "SP2040") were mixed at a mass ratio of 25:50:25 and melt-extruded by the T-die method to form a film, and the cooled resin sheet (basis weight of about 800 g / m 2 , thickness 0.85 mm) (resin) The following were prepared as the resin constituting the three-dimensional network. 100 parts by mass of polypropylene resin (manufactured by Nippon Polypropylene Corporation, trade name "SA01A") mixed with a black pigment masterbatch (spinning nozzle) The following were prepared as the spinning nozzles used for manufacturing the three-dimensional network. A nozzle that is long in the width direction, with holes having a pore diameter of 1.0 mm arranged in the width direction at an adjacent hole pitch of 5.0 mm, and the distance between the outermost holes being 2000 mm (mounting piece) The following sheet was prepared as the mounting piece. Fabric: basis weight 120 g / m 2 , thickness 0.20 mm, size in the width direction 30 cm, made of nylon fiber

[0069] [Comparative Example 1] (Manufacture of three-dimensional network) A nonwoven fabric for the water-permeable layer was placed on the conveying belt, the above resin was heated and melted, discharged from the above spinning nozzle, and while hanging continuous filaments onto a mold with a depth of 5.0 mm, the belt was moved in the machine direction to form a three-dimensional network. Before the continuous filaments solidified, the nonwoven fabric for the water-permeable layer was laminated on the three-dimensional network, and a laminate of the nonwoven fabric for the water-permeable layer and the three-dimensional network was manufactured while being pressure-bonded and integrated with a pressing roll from the side of the nonwoven fabric for the water-permeable layer. The obtained three-dimensional network had a fiber diameter of the filaments of about 1.0 mm, a thickness of 5.0 mm, and an overall basis weight of about 300 g / m 2Its overall width was approximately 2000 mm and it did not have a low basis weight zone. The nonwoven fabric for the permeable layer and the three-dimensional reticulated body were integrally bonded by the cooling and solidification of continuous filaments. (Installation of attachment pieces) For the laminate of the nonwoven fabric and the three-dimensional reticulated body, a sheet serving as an attachment piece was placed on the three-dimensional reticulated body, and the attachment piece and the nonwoven fabric were sewn together through the three-dimensional reticulated body with a sewing machine. The joining location (sewing location) was approximately at the center in the width direction of the laminate and was sewn linearly along the longitudinal direction (machine direction). The joining (sewing) was performed with two sewing lines that were substantially parallel to each other, and the width of the joining location (sewing location), that is, the distance between the two sewing lines, was approximately 20 mm. (Lamination with the water barrier layer) After dotting a hot melt adhesive made of ethylene-vinyl acetate copolymer on the surface of the resin sheet for the water barrier layer, the nonwoven fabric side of the laminate was bonded to the resin sheet and laminated integrally to obtain the waterproof sheet of Comparative Example 1. The interval between adjacent dot-shaped adhesives was 25 cm in the longitudinal direction (machine direction) and 40 cm in the width direction.

[0070] [Example 1] The following processing was performed on the spinning nozzle for manufacturing the three-dimensional reticulated body. (Processing of the spinning nozzle) At the center in the width direction of the nozzle, half of the number of holes were blocked so that the interval between adjacent holes was 10 mm over 100 mm, and the number of continuous filaments discharged from the center was halved. (Manufacture of the three-dimensional reticulated body, installation of attachment pieces, lamination with the water barrier layer) The three-dimensional reticulated body was manufactured in the same manner as in Comparative Example 1. The obtained three-dimensional reticulated body had a low basis weight zone where the basis weight was lower than the others at the center in the width direction of the three-dimensional reticulated body. The width in the width direction of the low basis weight zone was approximately 100 mm. The overall basis weight of the three-dimensional reticulated body was approximately 300 g / m 2 and the basis weight of the low basis weight zone was approximately 150 g / m 2 The overall width was approximately 2000 mm, the fiber diameter of the filament was approximately 1.0 mm, and the thickness was approximately 5.0 mm. The attachment piece was installed in the same manner as in Comparative Example 1 at the low basis weight band portion, and the lamination with the water barrier layer was performed in the same manner as in Comparative Example 1 to obtain the waterproof sheet of Example 1.

[0071] [Example 2] In the processing of the spinning nozzle, except that the width blocking the holes was changed from 100 mm to 120 mm, the waterproof sheet of Example 2 was obtained in the same manner as in Example 1. The width of the low basis weight band of the three-dimensional network body was about 120 mm.

[0072] [Example 3] In the production of the three-dimensional network body, except that the overall basis weight of the three-dimensional network body was changed from about 300 g / m 2 to about 400 g / m 2 and the basis weight of the low basis weight band was changed from about 150 g / m 2 to about 200 g / m 2 the waterproof sheet of Example 3 was obtained in the same manner as in Example 2.

[0073] [Example 4] In the production of the three-dimensional network body, except that the overall basis weight of the three-dimensional network body was changed from about 300 g / m 2 to about 500 g / m 2 and the basis weight of the low basis weight band was changed from about 150 g / m 2 to about 210 g / m 2 the waterproof sheet of Example 4 was obtained in the same manner as in Example 2.

[0074] [Example 5] In the processing of the spinning nozzle, the width blocking the holes was changed from 100 mm to 120 mm, and also the frequency of blocking the holes was changed so that only 1 hole out of 6 holes was blocked, and the number of continuous filaments discharged from the central portion in the width direction of the nozzle was reduced to 5 / 6, and except that the basis weight of the low basis weight band of the three-dimensional network body was about 250 g / m 2 the waterproof sheet of Example 5 was obtained in the same manner as in Example 1. The width of the low basis weight band of the three-dimensional network body was about 120 mm.

[0075] [Example 6] In the processing of the spinning nozzle, a waterproof sheet of Example 6 was obtained in the same manner as in Example 1, except that the width blocking the holes was changed from 100 mm to 150 mm. The width of the low basis weight band of the three-dimensional network body was about 150 mm.

[0076] The workability of the mounting pieces in the examples and comparative examples was evaluated as described above, and the results are shown in Table 1 below.

[0077]

Table 1

[0078] In the waterproof sheets of Examples 1 to 6, since the three-dimensional network body had a low basis weight band and the mounting pieces were overlapped and sewn on the surface of the low basis weight band, almost no thread breakage occurred and the workability was good. In Comparative Example 1 where the three-dimensional network body did not have a low basis weight band, when the mounting pieces were sewn continuously for 60 m in the longitudinal direction, thread breakage occurred 4 times and the workability was poor.

Industrial Applicability

[0079] The waterproof sheet for tunnels of the present invention can be suitably used as a waterproof sheet that discharges the 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.

Explanation of Signs

[0080] 1 Waterproof sheet for tunnel 2 Water barrier layer 3 Permeable layer 4 Three-dimensional network body 5 Mounting piece 6 Adhesive 7 Bonding line (bonding location) LD Longitudinal direction WD Width direction

Claims

1. A waterproof sheet for tunnels, comprising a water-blocking layer, a water-permeable layer, a three-dimensional net-like body, and an attachment piece attached to the primary lining concrete surface of the tunnel, wherein the water-blocking layer, the water-permeable layer, and the three-dimensional net-like body are laminated in the order of the water-blocking layer, the water-permeable layer, and the three-dimensional net-like body, the three-dimensional net-like body has a low basis weight band with a lower basis weight than other locations, the attachment piece is disposed on the surface of the three-dimensional net-like body opposite to the water-permeable layer, the attachment piece and the water-permeable layer are joined with the three-dimensional net-like body sandwiched therebetween, and the joining location exists parallel to the longitudinal direction of the waterproof sheet for tunnels, A waterproof sheet for tunnels, wherein the portion of the three-dimensional net-like body sandwiched by the joining location is located in the low basis weight band.

2. The waterproof sheet for tunnels according to claim 1, wherein the overall basis weight of the three-dimensional net-like body is 200 g / m 2 or more.

3. 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 basis weight band to the overall basis weight is 0.30 or more and 0.90 or less.

4. The waterproof sheet for tunnels according to any one of claims 1 to 3, wherein the width of the low basis weight band is 50 mm or more.

5. The waterproof sheet for tunnels according to any one of claims 1 to 4, wherein the ratio of the width of the low basis weight band to the overall width of the three-dimensional net-like body is 0.20 or less.

6. The waterproof sheet for tunnels according to any one of claims 1 to 5, wherein the basis weight of the low basis weight band is 80 g / m 2 or more and 250 g / m 2 or less.

7. A method for manufacturing a waterproof sheet for tunnels, comprising a water-blocking layer, a water-permeable layer, a three-dimensional net-like body, and an attachment piece attached to the primary lining concrete surface of the tunnel, A step of providing a low basis weight band having a lower basis weight than other portions on the three-dimensional network by manufacturing using a spinneret in a state where a part of the holes existing in the central portion in the width direction of the three-dimensional network is blocked. In the laminate of the three-dimensional network and the water-permeable layer, a mounting piece is overlapped on the surface of the low basis weight band on the side opposite to the water-permeable layer of the three-dimensional network, and the mounting piece and the water-permeable layer are joined so that the joining portion exists parallel to the longitudinal direction of the waterproof sheet for tunnels, and A method for manufacturing a waterproof sheet for tunnels, including a step of laminating and integrating a water shielding 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 the three-dimensional network, the ratio of the basis weight of the low basis weight band to the overall 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 the low basis weight band is 50 mm or more.

10. 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 the low basis weight band to the overall width of the three-dimensional network is 0.20 or less.

11. The basis weight of the low basis weight band is 80 g / m 2 or more and 250 g / m 2 or less. The method for manufacturing a waterproof sheet for tunnels according to any one of claims 7 to 10.

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