Water stop material for segment and water stop structure for segment

Abstract

This water stop material seals an insertion hole formed in a segment of a shield tunnel. The water stop material has elasticity, is formed in an annular shape in a front view as seen from the insertion direction of the insertion hole, and is arranged so as to face an insertion end part that is an end part of the insertion hole. The water stop material includes: an inner peripheral surface that is the inner surface of the annular shape and includes a plurality of ridge parts protruding inward in the radial direction; an insertion facing surface that is an outer surface facing the insertion end part; and a locking facing surface that is an outer surface facing a locking member locking the water stop material. In a state where the water stop material is not deformed, at least a part of the insertion facing surface is arranged inside the insertion end part, and the locking facing surface is arranged outside the insertion end part.

Description

Segment water-stop material and segment water-stop structure

[0001] The present disclosure relates to a segment water-stop material and a segment water-stop structure. This application claims priority based on Japanese Patent Application No. 2025-053033 filed in Japan on March 27, 2025, the content of which is incorporated herein by reference.

[0002] In the construction field, the shield tunneling method, in which a shield machine excavates the ground to construct a shield tunnel, is widely used. A shield tunnel constructs its wall surface by connecting a plurality of segments with bolts or the like. Since the connecting portion of these segments is constructed underground, a water-stop structure that prevents inflow of groundwater into the tunnel is adopted.

[0003] Conventionally, as disclosed in, for example, Patent Document 1, a segment joint bolt water-stop structure is known in which a packing is fitted into a groove provided at an end of a bolt through-hole of a segment.

[0004] Japanese Utility Model Laid-Open No. 57-160400

[0005] In the construction field in recent years, development of shield tunnels that can be constructed at deeper positions than before is expected. However, in the prior art, the influence of groundwater pressure increases with depth, so higher water-stop performance is required for the connecting portion of segments, and there has been a problem that the water-stop performance is insufficient.

[0006] The present disclosure has been made in consideration of such circumstances, and an object thereof is to provide a segment water-stop material and a segment water-stop structure having high water-stop performance.

[0007] To achieve the above objectives, the Disclosure provides the following means. The segment sealing material of the Disclosure is a sealing material for sealing an insertion hole formed in a segment of a shield tunnel, the sealing material being elastic, formed in an annular shape in a front view as seen from the insertion direction of the insertion hole, and positioned to face the insertion end which is the end of the insertion hole, and comprising an inner circumferential surface which is the inner surface of the annular shape and has a plurality of protrusions projecting radially inward, an insertion-facing surface which is the outer surface facing the insertion end, and a locking-facing surface which is the outer surface facing a locking device that locks the sealing material, wherein, in a state in which the sealing material is not deformed, at least a portion of the insertion-facing surface is positioned inside the insertion end, and the locking-facing surface is positioned outside the insertion end.

[0008] The segment watertight structure of the present disclosure is a segment watertight structure using a segment watertight material, comprising: a segment having a through-hole extending in the insertion direction and constructing the wall surface of the shield tunnel; a fastener formed in the shape of a rod that can be inserted into the through-hole and having a fastening portion formed at least at one end; and locking devices provided at both ends of the fastener and formed to be larger than the watertight material when viewed from the insertion direction, wherein the fastener is inserted into the through-hole with the watertight material positioned at the insertion end, and fastens the fastening portion while inserted into the insertion hole; the locking devices are positioned to face the locking-facing surface when the fastener is inserted into the through-hole, and lock the watertight material outside the segment so as to press it toward the insertion direction when fastened, and the watertight material, when deformed due to the pressing, is smaller than the locking devices when viewed from the insertion direction.

[0009] According to this disclosure, it is possible to provide a water-sealing material for segments and a water-sealing structure for segments that have high water-sealing performance.

[0010] This is a cross-sectional view showing the segments connected according to the embodiment of this disclosure. This is a perspective view of a waterproofing material used in a waterproofing structure according to the embodiment of this disclosure. This is a front view of the waterproofing material according to the embodiment of this disclosure, viewed from the insertion direction. This is a side cross-sectional view of the waterproofing material according to the embodiment of this disclosure, viewed from the radial direction. This is a partially enlarged view of the waterproofing material according to the embodiment of this disclosure. This is a side cross-sectional view of the insertion end of the first segment, viewed from the radial direction, before fastening the fastener according to the embodiment of this disclosure. This is a side cross-sectional view of the insertion end of the first segment, viewed from the radial direction, with the fastener according to the embodiment of this disclosure fastened.

[0011] Embodiments of this disclosure will be described with reference to Figure 1-7. In this disclosure, the drawings are schematic diagrams for easy understanding of the configuration, and the dimensional ratios of each component may differ from those of the actual components. The R axis and Z axis are shown in the drawings as appropriate. The direction along the Z axis, which curves at a predetermined angle, is defined as the "insertion direction Z". The direction along the R axis is perpendicular to the insertion direction Z and is defined as the "radial direction R". Within the insertion direction Z, the side in which the Z-axis arrow points is called the inside (+Z side), and the side opposite to the side in which the Z-axis arrow points is called the outside (-Z side). Within the radial direction R, the side in which the R-axis arrow points is called the radial outside (+R side), and the side opposite to the side in which the R-axis arrow points is called the radial inside (-R side). In addition, in this disclosure, the viewpoint seen from the insertion direction Z is defined as the "front view", and the viewpoint seen from the radial direction R is defined as the "side view".

[0012] <Configuration of the water-sealing structure> The water-sealing structure 1 of the segment 3 according to the embodiment of this disclosure will be described with reference to Figure 1. Figure 1 is a cross-sectional view showing the segment 3 in a connected state. The water-sealing structure 1 comprises a water-sealing material 2, a segment 3, a fastener 4, and a locking device 5.

[0013] The waterproofing material 2 is a member that is formed in an annular shape when viewed from the front, and possesses water-swellability and elasticity, such as water-swellable rubber. This waterproofing material 2 is positioned to face and contact the insertion end 311 of the insertion hole 31 of the segment 3, which will be described later. Furthermore, the waterproofing material 2 is formed to be larger than the insertion hole 31 when viewed from the front.

[0014] Segment 3 is a precast concrete block formed with a curved surface. This segment 3 has an insertion hole 31, an insertion space 32, a contact surface 33, a tunnel inner surface 34, and a tunnel outer surface 35. The first segment 3a and the second segment 3b, which are adjacent segments 3, are connected to form a part of the outer wall of the shield tunnel having a circular cross-section.

[0015] The through-hole 31 is a through-hole extending along the insertion direction Z, which curves with a predetermined radius of curvature, and is provided through which a fastener 4 can be inserted. The first through-hole 31a of the first segment 3a and the second through-hole 31b of the second segment 3b form a single connecting through-hole 31 when connected.

[0016] The insertion space 32 is the internal space of the segment 3 located near the insertion end 311, which is the end of the insertion hole 31. This insertion space 32 has a fastening surface 321 formed parallel to the radial direction R. The insertion end 311 is formed on the fastening surface 321. Furthermore, the insertion end 311 formed on the fastening surface 321 is provided with a groove-shaped chamfer formed at approximately 45°.

[0017] The contact surface 33 is one of the planes of the segment 3, and is the surface that adjacent segments 3 come into contact with each other. The first segment 3a and the second segment 3b are arranged in a connected state such that the first contact surface 33a and the second contact surface 33b come into contact with each other.

[0018] The tunnel surface 34 is one of the curved surfaces of segment 3 and is the finished surface exposed inside the shield tunnel. The first tunnel surface 34a of the first segment 3a and the second tunnel surface 34b of the second segment 3b form a single continuous tunnel surface 34 when connected.

[0019] The tunnel exterior surface 35 is one of the curved surfaces of segment 3 and is the surface that substantially abuts the ground outside the shield tunnel. The first tunnel exterior surface 35a of the first segment 3a and the second tunnel exterior surface 35b of the second segment 3b are arranged to form a single continuous tunnel exterior surface 35 when connected.

[0020] The material, shape, and structure of the segment 3 are not particularly limited, as long as they can be connected with the water-stopping material 2 placed at the insertion end 311. For example, the segment 3 is formed in a block shape including a curved surface, but it may also be formed in a block shape without a curved surface. In that case, the segments 3 are connected to construct a shield tunnel with a rectangular cross-section. The insertion direction Z is a direction that curves at a predetermined angle, but it may also be a straight direction without curvature. In that case, the segments 3 are connected by fasteners 4 inserted through insertion holes 31 that extend along a straight line. The insertion holes 31 are provided to connect two adjacent segments 3, but they may also be provided to connect two or more segments 3. In that case, two or more segments 3 are connected using one fastener 4. The insertion holes 31 are through holes provided in the segment 3 body, but a tubular member such as a sheath may be placed inside. In that case, the fasteners 4 are protected from groundwater, etc., by the sheath. Furthermore, although the inner surface 34 and outer surface 35 of the tunnel are arranged to form a single plane, irregularities, steps, and openings may be provided as appropriate. In that case, the irregularities, steps, and openings will be utilized in the construction of equipment and other facilities provided in the shield tunnel.

[0021] The fastener 4 is a rod-shaped steel member, such as a bolt, that extends along the insertion direction Z. The fastener 4 is formed to be longer than the insertion hole 31 and is inserted into the insertion hole 31 and the water-stopping material 2 such that both ends are positioned outside (-Z side) of the insertion end 311. A male threaded fastening portion 41 is formed at the end of the fastener 4 on the second segment 3b side and is fastened with a nut 411. A bolt head 42 is formed at the end of the fastener 4 on the first segment 3a side.

[0022] The locking device 5 is a steel member used for fastening, for example, washers, to both ends of the fastener 4. When viewed from the front, the locking device 5 is larger than the water-sealing material 2. The locking device 5 is also located on the outside (-Z side) of the water-sealing material 2. The end of the fastener 4 on the first segment 3a side is provided with a locking device 5a, which is a washer positioned inside (+Z side) of the bolt head 42. The end of the fastener 4 on the second segment 3b side is provided with a locking device 5b, which is a washer positioned inside (+Z side) of the nut 411 of the fastening portion 41.

[0023] The fastener 4, inserted through the through hole 31 and the waterproofing material 2, generates a fastening force directed inward (+Z side) in the insertion direction Z when the fastening portion 41 and the locking device 5b are fastened together. This fastening force connects the first segment 3a and the second segment 3b. At this time, the locking device 5 abuts against and locks with the waterproofing material 2. The waterproofing material 2, positioned between the locking device 5 and the fastening surface 321, is pressed inward (+Z side) by the fastening force and deforms to seal the through end 311. The pressed waterproofing material 2 prevents groundwater 6 (see Figure 7) flowing in from the ground outside the shield tunnel through the contact surface 33 and the through hole 31 from flowing out to the outside (-Z side) of the through end 311. Furthermore, since the pressed waterproofing material 2 is water-expandable, it expands upon contact with the groundwater 6, further sealing the through end 311.

[0024] The material, shape, and configuration of the fasteners 4 and locking devices 5 are not particularly limited, as long as they can connect the segments 3 so as to seal the insertion end 311 by the deformation of the waterproofing material 2. For example, the insertion hole 31 is a space through which only the fastener 4 is inserted, but concrete may be poured after the fastener 4 is fastened. In that case, the connection strength of the segments 3 is improved, and the fastener 4 is protected from groundwater, etc. The locking device 5 may be formed integrally with the bolt head 42 and nut 411, or it may not be arranged separately. In that case, the bolt head 42 and nut 411 are formed to be larger than the waterproofing material 2 when viewed from the front, so that the waterproofing material 2 can deform to seal the insertion end 311. The fasteners 4 connect the segments 3 by fastening force, but the fixing method may involve welding, or it may be fixed by welding alone without fastening. In this case, the insertion end 311 is fixed in a sealed state by the water-sealing material 2 by welding the fastener 4 while the water-sealing material 2 is pressed inward (towards the +Z side). The water-swellability of the water-sealing material 2 is less than or equal to a water expansion coefficient of 100%, but it may also have a lower water-swellability. As a particularly preferred example, the water-swelling material 2 may be made of a water-swellable material having a water expansion coefficient of 75% or less, more preferably 50% or less. In this case, excessive expansion of the water-sealing material 2 is further suppressed, preventing damage and detachment. At this time, the pressing force of the water-sealing material 2 decreases with decreasing water expansion coefficient, but the water-sealing material 2 of this disclosure can ensure sealing force by providing the protruding portion 211. The water expansion coefficient of the water-sealing material 2 is preferably 10% or more, more preferably 20% or more. In this case, the water-swellability of the water-sealing material 2 can be fully exercised, and water-sealing can be more reliably ensured. The water expansion coefficient can be measured by an immersion test using Archimedes' principle. In this immersion test, a test specimen with the waterproofing material 2 attached is pierced with a needle and suspended, then placed in a water tank on a scale, and its volume before immersion is measured. After that, the test specimen is immersed in the water tank (23°C ± 2°C) for 10 days, and its volume is measured again. The rate of volume change (coefficient of water expansion) is calculated using the following formula: {(Volume after immersion - Volume before immersion) / Volume before immersion} × 100.Furthermore, the water-swellable material is not particularly limited, but water-swellable materials including rubber and water-swellable resins can be used. Examples of rubber include natural rubber, styrene-butadiene rubber, acrylonitrile butadiene rubber, chloroprene rubber, butadiene rubber, ethylene propylene rubber, acrylic rubber, epichlorohydrin rubber, silicone rubber, chlorosulfonated polyethylene rubber, and fluorine-based rubber. Examples of water-absorbent resins include various cross-linked water-swellable resins such as acrylic acid-based, acrylate-based, maleic anhydride-based, urethane-based, and polyvinyl alcohol-based resins. In addition, the fastener 4 has a fastening portion 41 at one end on the second segment 3b side, but fastening portions 41 may be formed at both ends. In that case, a bolt head 42 is not formed at the other end of the fastener 4, and nuts 411 are placed at both ends and fastened.

[0025] <Structure of the waterproofing material> The waterproofing material 2 of the segment 3 according to the embodiment of this disclosure will be described with reference to Figure 2-5. Figure 2 is a perspective view of the waterproofing material 2 used in the waterproofing structure 1. Figure 3 is a front view of the waterproofing material 2 as seen from the insertion direction Z. Figure 4 is a cross-sectional view of the waterproofing material 2 along A-A (side cross-section as seen from the radial direction R). Figure 5 is an enlarged view of the waterproofing material 2 at B. Figure 2-5 shows the waterproofing material 2 in an undeformed state. As shown in Figure 2-4, the waterproofing material 2 is formed in a substantially triangular shape in a side cross-section as seen from the radial direction R, and has three surfaces: an inner circumferential surface 21, an insertion-facing surface 22, and a locking-facing surface 23. The waterproofing material 2 also has three corners: an inner corner 24, an intermediate corner 25, and an outer corner 26.

[0026] The inner circumferential surface 21 is the inner surface of the water-sealing material 2, formed in a substantially cylindrical shape along the insertion direction Z. The inner diameter of the space on the radially inward side (-R side) of this inner circumferential surface 21 is smaller than the inner diameter of the insertion hole 31 and larger than the fastener 4. Specifically, the inner diameter of the inner circumferential surface 21 is formed in an annular shape that is 85% of the inner diameter of the insertion hole 31. The inner diameter of the inner circumferential surface 21 can be appropriately set according to the outer diameter of the fastening portion 41. From the viewpoint of properly sealing water by positioning a part of the water-sealing material 2 inside the insertion end 311 while remaining near the insertion end 311, and reducing the volume of the water-sealing material 2 to suppress manufacturing costs, the inner diameter of the inner circumferential surface 21 is preferably 60% or more, and more preferably 75% or more, of the inner diameter of the insertion hole 31. Furthermore, the inner diameter of the inner circumferential surface 21 is preferably less than 100% of the inner diameter of the insertion hole 31, and more preferably 90% or less, so that a portion of the water-stopping material 2 can be positioned inside the insertion end 311. The inner circumferential surface 21 is also provided with a plurality of protrusions 211 that project radially inward (-R side) from the inner circumferential surface 21.

[0027] The protruding portion 211 is made of the same material as the water-sealing material 2 and is formed integrally with it. The inner diameter of the annular portion formed at one end of the radially inner (-R side) protruding portion 211 is smaller than the inner diameter of the inner circumferential surface 21 when viewed from the front, and is formed in an annular shape that is slightly larger than the fastener 4. Specifically, the inner diameter of the protruding portion 211 is formed in an annular shape that is 81% of the inner diameter of the insertion hole 31. From the viewpoint of water-sealing, the inner diameter of the protruding portion 211 is preferably 40% or more, more preferably 50% or more, and even more preferably 73% or more of the inner diameter of the insertion hole 31. Furthermore, in order to more appropriately incorporate the water-sealing material 2 between the fastener 4 and the insertion hole 31, the inner diameter of the protruding portion 211 is preferably less than 99% of the inner diameter of the insertion hole 31, and more preferably 87% or less. In addition, in the insertion direction Z, the protruding portion 211 is formed to be 1 to 20% of the size of the inner circumferential surface 21. The size of the protruding portion 211 is preferably 1% or more, and more preferably 3% or more, of the size of the inner circumferential surface 21 in order to properly adhere the water-sealing material 2 and the fastener 4 and to exhibit better water-sealing properties. Furthermore, the size of the protruding portion 211 is preferably 20% or less, more preferably 10% or less, and even more preferably 8% or less, of the size of the inner circumferential surface 21 in order to properly ensure the pressing force of the protruding portion 211 against the fastener 4 and to exhibit better water-sealing properties. The protruding portion 211 formed within the above range can properly press against the outer surface of the fastener 4 and exhibit better water-sealing properties. Multiple protruding portions 211 form irregularities on the inner circumferential surface 21. In addition, in the insertion direction Z, the sum of the sizes of the multiple protruding portions 211 is formed to occupy a range of 3 to 60% of the inner circumferential surface 21. The sum of the sizes of the multiple protrusions 211 in the insertion direction Z is preferably 3% or more, and more preferably 6% or more, of the size of the inner circumferential surface 21, in order to properly ensure close contact between the water-sealing material 2 and the fastener 4 and to exhibit better water-sealing properties. Furthermore, the sum of the sizes of the multiple protrusions 211 in the insertion direction Z is preferably 60% or less, more preferably 30% or less, and even more preferably 24% or less, of the size of the inner circumferential surface 21, in order to more appropriately ensure the pressing force of the protrusions 211 against the fastener 4 and to exhibit better water-sealing properties.

[0028] The insertion-facing surface 22 is the outer surface of the water-sealing material 2 formed on the inner side (+Z side). The radially outer (+R side) end of this insertion-facing surface 22 is formed in an annular shape that is larger than the insertion hole 31 when viewed from the front. Specifically, the radially outer (+R side) end of the insertion-facing surface 22 is formed in an annular shape that is 130% of the inner diameter of the insertion hole 31. The radially outer (+R side) end of the insertion-facing surface 22 is preferably 100% or more of the inner diameter of the insertion hole 31, and more preferably 115% or more, in order to facilitate the installation of the water-sealing material 2 and to exhibit better water-sealing performance at the end of the insertion hole 31. Furthermore, the radially outer (+R side) end of the insertion-facing surface 22 is preferably 160% or less of the inner diameter of the insertion hole 31, and more preferably 145% or less, in order to suppress the water-sealing material 2 from protruding from the locking device 5a and to improve the appearance. Furthermore, as shown in Figure 4, the insertion-facing surface 22 is formed in a straight line that extends from one end on the inside (+Z side) and radially inward (-R side) toward the other end on the outside (-Z side) and radially outward (+R side) when viewed from the side.

[0029] The locking opposing surface 23 is the outer surface of the water-sealing material 2 formed on the outside (-Z side). When viewed from the front, the locking opposing surface 23 is formed in an annular shape that is substantially the same as the insertion opposing surface 22. Furthermore, when viewed from the side, the locking opposing surface 23 is formed in a straight line extending from one end on the inside (+Z side) and radially outward (+R side) toward the other end on the outside (-Z side) and radially inward (-R side).

[0030] The inner corner portion 24 is a corner formed at the inner (+Z side) end of the water-sealing material 2 in a side view. This inner corner portion 24 is the intersection of the inner (+Z side) end of the inner circumferential surface 21 and the inner (+Z side) end of the insertion-facing surface 22, forming an acute angle of approximately 54.5 degrees. The angle of the inner corner portion 24 is preferably 30 degrees or more, and more preferably 45 degrees or more, in order to properly seal the water-sealing material 2 between the insertion hole 31 and the fastener 4 and to further improve water-sealing. Furthermore, the angle of the inner corner portion 24 is preferably 70 degrees or less, and more preferably 60 degrees or less, in order to easily fit the water-sealing material 2 inside the insertion hole 31 and to further improve water-sealing.

[0031] The intermediate corner portion 25 is a corner formed at the radially outer (+R side) end of the water-stopping material 2 in a side view. This intermediate corner portion 25 is the intersection of the outer (-Z side) end of the insertion-facing surface 22 and the inner (+Z side) end of the locking-facing surface 23, forming an acute angle of approximately 71 degrees. From the viewpoint of the ease with which the water-stopping material 2 can be crushed and the fit with the locking device 5a improves water-stopping performance, the angle of the intermediate corner portion 25 is preferably 40 degrees or more, more preferably 55 degrees or more, and the angle of the intermediate corner portion 25 is preferably 90 degrees or less, more preferably 85 degrees or less.

[0032] The outer corner portion 26 is a corner formed at the outer (-Z side) end of the water-stopping material 2 in a side view. This outer corner portion 26 is the intersection of the outer (-Z side) end of the inner circumferential surface 21 and the outer (-Z side) end of the locking opposing surface 23, forming an acute angle of approximately 54.5 degrees. From the viewpoint of the ease with which the water-stopping material can be crushed and the water-stopping properties due to the fit with the locking device 5a, the angle of the outer corner portion 26 is preferably 30 degrees or more, and more preferably 45 degrees or more. Furthermore, the angle of the outer corner portion 26 is preferably 70 degrees or less, and more preferably 60 degrees or less.

[0033] As shown in Figure 5, the straight-line distance from the inner circumferential surface 21 to the intermediate corner portion 25 in the radial direction R is defined as the main body diameter length L1. Furthermore, if the size of the protrusion portion 211 in the radial direction R is defined as the protrusion diameter length L2, then the protrusion diameter length L2 is formed to be 1 to 10% of the main body diameter length L1. If the protrusion diameter length L2 is too large, the moldability is poor, and if it is too small, the water-sealing ability decreases, so the above range provides a good balance between moldability and water-sealing ability. In addition, it is more preferable that the protrusion diameter length L2 be 2% or more of the main body diameter length L1 in order to fix the positional relationship between the water-sealing material 2 and the fastener 4 and to exhibit better water-sealing ability. Furthermore, from the viewpoint of the difficulty of molding, it is more preferable that the protrusion diameter length L2 be 5% or less of the main body diameter length L1.

[0034] The waterproofing material 2 constructed in this manner is formed in a symmetrical triangular shape in a side cross-sectional view, allowing it to fit neatly into the insertion end 311 and deform easily in the insertion direction Z, thus providing high waterproofing properties. Furthermore, the waterproofing material 2 has good moldability and high productivity. In addition, the waterproofing material 2, with its effectively sized protrusions 211, makes tight contact with the insertion end 311 and the locking device 5 under high pressure.

[0035] The material, shape, and configuration of the water-sealing material 2 are not particularly limited, as long as a portion of the water-sealing material 2 can be positioned inside the insertion hole 31 and can seal the insertion end 311 when pressed. For example, the water-sealing material 2 may be formed in a polygonal shape when viewed from the front. In that case, it will be provided in an optimal shape according to the shape of the locking device 5. The water-sealing material 2 does not need to be water-swellable. Even in that case, the water-sealing material 2 can seal the insertion end 311 by elastic deformation accompanying the pressing. The water-sealing material 2 may also be formed in a polygonal shape in a side cross-section viewed from the radial direction R, and may have three or more faces and three or more corners. In that case, the water-sealing material 2 can seal the insertion end 311 by having a shape in which at least a portion is positioned outside (-Z side) of the insertion hole 31 when elastically deformed due to pressing. The insertion-facing surface 22 and the locking-facing surface 23 of the water-sealing material 2 may have protrusions or indentations similar to the ridge portion 211. In that case, the friction and pressure generated between the water-stopping material 2, the insertion end 311, and the locking device 5 increase, improving the airtightness of the insertion end 311.

[0036] <Construction of the Watertight Structure> The procedure for constructing the watertight structure 1 of the segment 3 according to the embodiment of this disclosure will be described with reference to Figure 6-7. Figure 6 is a side cross-sectional view of the insertion end 311 of the first segment 3a as seen from the radial direction R, before fastening the fastener 4. Here, the watertight material 2 that does not deform before pressing is defined as the undeformed watertight material 2c. The watertight material 2 that is deformed after pressing is defined as the deformed watertight material 2d.

[0037] First, the undeformed waterproofing material 2c is positioned. As shown in Figure 6, the undeformed waterproofing material 2c is positioned so that the insertion-facing surface 22 abuts against the insertion end 311 of the fastening surface 321. At this time, a part of the insertion-facing surface 22 and the inner corner 24 are positioned on the inside (+Z side) of the insertion end 311, i.e., inside the insertion hole 31. On the other hand, the locking-facing surface 23, the intermediate corner 25, and the outer corner 26 are positioned on the outside (-Z side) of the insertion end 311.

[0038] Next, the locking device 5a is positioned. The locking device 5a is a washer formed in the shape of a plate with a step that is recessed toward the outside (-Z side). This locking device 5a is positioned to face the locking opposing surface 23 of the undeformed waterproofing material 2c.

[0039] Next, the fastener 4 is positioned. The fastener 4 has a fastening portion 41 (not shown in Figure 6) that is inserted into the locking device 5a, the undeformed waterproofing material 2c, and the insertion hole 31. Once the fastener 4 is inserted, the bolt head 42 side of the fastener 4 is positioned near the locking device 5a. The protruding portion 211 is positioned close to the side surface of the fastener 4.

[0040] Next, the fastener 4 is fastened. Figure 7 is a side cross-sectional view of the insertion end 311 of the first segment 3a, viewed from the radial direction R, in a state where the fastening portion 41 (not shown in Figure 7) is fastened with the nut 411. As shown in Figure 7, the fastener 4 connects the first segment 3a and the second segment 3b and generates a pressing force (pressure) P directed inward (towards the +Z side).

[0041] The undeformed waterproofing material 2c transitions into a deformed waterproofing material 2d due to the pressing force P of the fastener 4. The deformed waterproofing material 2d deforms in the insertion direction Z, sealing the insertion end 311 without any gaps. The insertion end 311 sealed by the deformed waterproofing material 2d prevents groundwater 6 flowing in from the outside (outside the tunnel surface 35 side) towards the insertion end 311 from flowing out to the outside (-Z side).

[0042] In this case, even in the deformable waterproofing material 2d, a part of the insertion-facing surface 22 and the inner corner portion 24 are positioned inside the insertion end portion 311 (+Z side), i.e., inside the insertion hole 31. The locking-facing surface 23, the intermediate corner portion 25, and the outer corner portion 26 are positioned outside the insertion end portion 311 (-Z side). Here, the deformable waterproofing material 2d, when in contact with groundwater 6, is smaller than the locking device 5a when viewed from the front, even in a water-expanded state. Furthermore, the protruding portion 211 effectively makes close contact with the side surface of the fastener 4 with higher pressure than the inner circumferential surface 21. Therefore, the deformable waterproofing material 2d does not fall out of the insertion hole 31 due to deformation and water expansion. In addition, since the deformable waterproofing material 2d is positioned in the small space between the fastening surface 321 and the locking device 5a, it is not visible from the outside.

[0043] The procedure for constructing the watertight structure on the first segment 3a side has been described above, but the same configuration and procedure can be used to construct the watertight structure 1 on the second segment 3b side as well.

[0044] According to the water stop material 2 for the segment 3 according to the embodiment, the water stop material 2 is a member that is formed in an annular shape when viewed from the front and has water swellability and elasticity, such as water-expandable rubber. This water stop material 2 is arranged so as to face and abut against the insertion end 311 of the insertion hole 31 of the segment 3. In addition, the water stop material 2 is formed larger than the insertion hole 31 when viewed from the front. Further, the inner peripheral surface 21 includes a plurality of protrusions 211 protruding radially inward (-R side) from the inner peripheral surface 21. The protrusions 211 are portions integrally formed of the same member as the water stop material 2. The inner diameter of the annular portion formed by one end of each protrusion 211 on the radially inner side (-R side) is smaller than the inner diameter of the inner peripheral surface 21 when viewed from the front, and is formed in an annular shape slightly larger than the fastener 4. In addition, the insertion facing surface 22 is the outer surface of the water stop material 2 formed on the inner side (+Z side). An end of the insertion facing surface 22 on the radially outer side (+R side) is formed in an annular shape larger than the insertion hole 31 when viewed from the front. In addition, the locking facing surface 23 is the outer surface of the water stop material 2 formed on the outer side (-Z side). This locking facing surface 23 is formed in a substantially identical annular shape as the insertion facing surface 22 when viewed from the front. A part of the insertion facing surface 22 of the unmodified water stop material 2c is arranged inside the insertion end 311 (+Z side), that is, inside the insertion hole 31. On the other hand, the locking facing surface 23 is arranged outside the insertion end 311 (-Z side). Therefore, the water stop material 2 is arranged to seal the insertion end 311, and since the protrusions 211 are in close contact with the side surface of the fastener 4 with higher pressure than the inner peripheral surface 21, high water stopping performance can be provided.

[0045] In addition, according to the water stop material 2 for the segment 3 according to the embodiment, the water stop material 2 has a physical property of water expansion coefficient of 100% or less. Therefore, since excessive expansion does not occur in the water stop material 2, it does not fall off or expose from the stopper 5 and the insertion end 311, can suppress occurrence of damage such as tearing, and ensures high water stopping performance.

[0046] According to the watertight structure 1 of the segment 3 according to this embodiment, the through hole 31 is a through hole extending along the insertion direction Z which curves with a predetermined radius of curvature, and is provided through which a fastener 4 can be inserted. The segment 3 is a precast concrete block formed including a curved surface, and by connecting them, it constructs a part of the outer wall of a shield tunnel having a circular cross-section. The fastener 4 is formed to be longer than the through hole 31 and is inserted through the through hole 31 and the watertight material 2 so that both ends are positioned on the outside (-Z side) of the insertion end 311. The locking devices 5 are provided at both ends of the fastener 4 and are formed to be larger than the watertight material 2 when viewed from the front. The locking devices 5 are positioned on the outside (-Z side) of the watertight material 2. The fastener 4 inserts its fastening portion 41 through the locking device 5a, the undeformed watertight material 2c, and the through hole 31. As the fastener 4 is fastened, the segments 3 are connected, and a pressing force (pressure) P directed inward (+Z side) is generated. The locking device 5 is positioned to face the locking-facing surface 23 of the undeformed waterproofing material 2c. The undeformed waterproofing material 2c transitions to a deformed waterproofing material 2d due to the pressing force P of the fastener 4. The locking device 5 contacts and locks with the waterproofing material 2. Thus, the waterproofing structure 1 of the segment 3 according to this embodiment allows for the construction of a shield tunnel with high waterproofing performance by connecting the segments 3 using the waterproofing material 2. Furthermore, since the waterproofing material 2 is smaller than the locking device 5 in the radial direction R, it does not fall off or become exposed, suppressing damage such as tearing. Thus, the waterproofing material 2 can ensure high waterproofing performance. In addition, since the waterproofing material 2 is not exposed on the finished surface (inner surface of the tunnel 34), it also has good aesthetic appeal.

[0047] Furthermore, according to the water-sealing structure 1 of the segment 3 according to the embodiment, even in the deformable water-sealing material 2d, a part of the insertion-facing surface 22 is positioned on the inside (+Z side) of the insertion end 311, that is, inside the insertion hole 31. Also, the locking-facing surface 23 is positioned on the outside (-Z side) of the insertion end 311. Therefore, the water-sealing structure 1 of the segment 3 according to the embodiment is positioned in the space between the contact surface 33 of the segment 3 and the locking device 5 even when pressed, and the insertion end 311 is always sealed by the pressing force P, thus providing higher water-sealing performance.

[0048] Further, according to the water stop structure 1 of the segment 3 according to the embodiment, the water stop material 2 is formed in a substantially triangular shape in a side cross-section viewed from the radial direction R, and includes three surfaces: an inner peripheral surface 21, an insertion opposing surface 22, and a locking opposing surface 23. The water stop material 2 also includes three corner portions: an inner corner portion 24, an intermediate corner portion 25, and an outer corner portion 26. The inner corner portion 24 is an intersection of an end portion on the inner side (+Z side) of the inner peripheral surface 21 and an end portion on the inner side (+Z side) of the insertion opposing surface 22, and forms an acute angle of approximately 54.5 degrees. Further, the intermediate corner portion 25 is an intersection of an end portion on the outer side (-Z side) of the insertion opposing surface 22 and an end portion on the inner side (+Z side) of the locking opposing surface 23, and forms an acute angle of approximately 71 degrees. Further, the outer corner portion 26 is an intersection of an end portion on the outer side (-Z side) of the inner peripheral surface 21 and an end portion on the outer side (-Z side) of the locking opposing surface 23, and forms an acute angle of approximately 54.5 degrees. The inner corner portion 24 of the undeformed water stop material 2c is arranged on the inner side (+Z side) of the insertion end portion 311, that is, inside the insertion hole 31. On the other hand, the intermediate corner portion 25 and the outer corner portion 26 are arranged on the outer side (-Z side) of the insertion end portion 311. Also in the deformed water stop material 2d, the inner corner portion 24 is arranged on the inner side (+Z side) of the insertion end portion 311. The intermediate corner portion 25 and the outer corner portion 26 are arranged on the outer side (-Z side) of the insertion end portion 311. Therefore, the water stop structure 1 of the segment 3 according to the embodiment does not cause the water stop material 2 to fall off from the insertion end portion 311 or be buried into the insertion hole 31 regardless of whether the water stop material 2 is deformed or not, so that it can ensure high water stop performance while being easy to install.

[0049] Further, according to the water stop structure 1 of the segment 3 according to the embodiment, in the radial direction R, the linear distance from the inner peripheral surface 21 toward the intermediate corner portion 25 is defined as a main body radial length L1. Further, when the dimension of the protrusion 211 in the radial direction R is defined as a protrusion radial length L2, the protrusion radial length L2 is formed to be 1 to 10% of the main body radial length L1. Therefore, since the water stop material 2 seals the insertion end portion 311 with effective pressure provided by the protrusion 211, it can further effectively have high water stop performance. In addition, the water stop material 2 has good moldability and high productivity.

[0050] Although embodiments of this disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes, etc., that do not depart from the gist of this disclosure. Furthermore, the components shown in the above embodiments can be combined as appropriate.

[0051] 1 Water-stopping structure 2, 2c, 2d Water-stopping material 3 Segment 4 Fastener 5 Locking device 21 Inner circumferential surface 22 Opposing insertion surface 23 Opposing locking surface 24 Inner corner 25 Intermediate corner 26 Outer corner 31 Insertion hole 211 Protruding part 311 Insertion end P Pressing force (pressure) R Radial direction Z Insertion direction

Claims

1. A waterproofing material for sealing through holes formed in segments of a shield tunnel, wherein the waterproofing material is elastic, formed in an annular shape when viewed from the insertion direction of the through hole, and arranged to face the insertion end which is the end of the through hole, and comprises an inner circumferential surface which is the inner surface of the annular shape and has a plurality of protrusions projecting radially inward, an insertion-facing surface which is the outer surface facing the insertion end, and a locking-facing surface which is the outer surface facing a locking device that locks the waterproofing material, wherein, in a state in which the waterproofing material is not deformed, at least a part of the insertion-facing surface is located inside the insertion end, and the locking-facing surface is located outside the insertion end, the waterproofing material for segments.

2. The water-sealing material for a segment according to claim 1, wherein the water-sealing material is formed from a member with a water expansion coefficient of 100% or less.

3. A segment water-sealing structure using a segment water-sealing material according to claim 1 or 2, comprising: a segment having a through-hole extending in the insertion direction and forming a through-hole for constructing the wall surface of the shield tunnel; a fastener formed in the shape of a rod that can be inserted into the through-hole and having a fastening portion formed at least at one end; and locking devices provided at both ends of the fastener and formed to be larger than the water-sealing material when viewed from the insertion direction, wherein the fastener is inserted into the through-hole with the water-sealing material positioned at the insertion end, and fastens the fastening portion while inserted into the insertion-hole; the locking devices are positioned to face the locking-facing surface when the fastener is inserted into the through-hole, and lock the water-sealing material outside the segment so as to press it toward the insertion direction when fastened, and the water-sealing material is smaller than the locking devices when viewed from the insertion direction in a deformed state due to the pressing.

4. The water-stopping structure for a segment according to claim 3, wherein even when the water-stopping material is deformed due to the pressing, at least a portion of the insertion-facing surface is located inside the insertion end, and the locking-facing surface is located outside the insertion end.

5. The water-stopping material is formed such that the inner circumferential surface, the insertion-facing surface, and the locking-facing surface are substantially triangular in a side cross-sectional view seen from the radial direction, and has an inner corner portion which is the intersection of the inner circumferential surface and the insertion-facing surface, an intermediate corner portion which is the intersection of the insertion-facing surface and the locking-facing surface, and an outer corner portion which is the intersection of the inner circumferential surface and the locking-facing surface, wherein in a state in which the water-stopping material is not deformed and in a state in which the water-stopping material is deformed, the inner corner portion is located inside the insertion end, and the intermediate corner portion and the outer corner portion are located outside the insertion end, the water-stopping structure for a segment according to claim 4.

6. The segment water-stopping structure according to claim 5, wherein, in the radial direction when the water-stopping material is not deformed, the size of the protrusion is formed to be 1 to 10% of the distance from the inner circumferential surface to the intermediate corner.

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