Segment piece, segment ring, and tunnel lining

Abstract

To provide a segment piece, a segment ring, and a tunnel lining capable of reducing stress generated in concrete.SOLUTION: The present invention comprises: a main body mainly made of concrete; a plurality of main reinforcements; a plurality of distribution reinforcements; and a plurality of compression steel members formed into a rod shape and embedded so as to extend inward from a circumferential end face of the main body toward a central part. The plurality of compression steel members have at least one of a plurality of inner compression steel members arranged on the inner circumferential side in a radial direction and a plurality of outer compression steel members arranged on the outer circumferential side in the radial direction. The plurality of inner compression steel members and the plurality of outer compression steel members have a cover thickness in the radial direction equivalent to or greater than that of the plurality of distribution reinforcements. Each of the plurality of compression steel members has: a straight portion extending from the end face and formed in a straight line; and an inclined portion provided at a tip of the straight portion, inclined with respect to an extension direction of the straight portion, and inclined from the outside of a segment piece toward the center as it moves from the straight portion to the tip when viewed in an axial direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to segment pieces, segment rings, and tunnel lining structures used as lining materials for tunnels and the like.

Background Art

[0002] In recent years, the shield method has become established in construction work for subways, road tunnels, sewers, power lines, communication lines, utility tunnels, and the like. In this shield method, RC (Reinforced-Concrete) segments are used as the lining structure for the excavation surface.

[0003] The RC segment bears the axial compressive force by concrete and steel bars. In the segment piece constituting the RC segment, main steel bars are arranged inside the concrete of the main body. However, in the conventional segment piece, the main steel bars do not extend to the joint part where the segment pieces are connected to each other, which is the end of the main body. Therefore, the joint part of the conventional segment piece bears the compressive force only by concrete. Thus, a segment piece with steel materials installed at the joint part has been proposed (see, for example, Patent Document 1).

[0004] When steel materials are installed at the joint part, the compressive force acting on the joint part can be borne by concrete and steel materials. Therefore, the segment piece with steel materials installed at the joint part can reduce the generated stress of concrete and can be made thinner than the conventional segment piece without steel materials installed at the joint part.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] As in Patent Document 1, there has been a structural proposal to install steel materials at the joint part to reduce the stress burden of concrete by the concrete and the steel materials. However, in reality, there are no details such as what kind of steel materials should be installed at what position or to what depth, and no verification tests or the like have been conducted. The manner of installing the steel materials has been poorly grounded.

[0007] The present invention solves the above problems, and provides a segment piece, a segment ring, and a tunnel lining structure that can reduce the generated stress of concrete by specifying the manner of installing steel materials.

Means for Solving the Problems

[0008] The segment piece according to the present invention is a segment piece that constitutes a segment ring formed in a cylindrical shape that covers the excavation surface of a tunnel by being arranged annularly and connected to each other in the circumferential direction. It includes a main body portion mainly made of concrete, a plurality of main reinforcement bars embedded inside the main body portion and arranged to extend in the circumferential direction of the segment ring, a plurality of force-retaining bars embedded inside the main body portion and arranged to extend in the radial direction and the axial direction of the segment ring to restrain the plurality of main reinforcement bars, and a plurality of compression steel materials embedded so as to extend inward from the circumferential end surface of the main body portion toward the central portion and formed in a rod shape. The plurality of compression steel materials have at least one of a plurality of inner circumferential side compression steel materials arranged on the inner circumferential side in the radial direction and a plurality of outer circumferential side compression steel materials arranged on the outer circumferential side in the radial direction. The plurality of inner circumferential side compression steel materials and the plurality of outer circumferential side compression steel materials have a cover thickness equal to or greater than that of the plurality of force-retaining bars in the radial direction. Each of the plurality of compression steel materials has a straight portion extending from the end surface and formed in a straight line, and an inclined portion provided at the tip of the straight portion and inclined with respect to the extending direction of the straight portion, and inclined from the outer side to the central side of the segment piece as it goes from the straight portion to the tip when viewed in the axial direction.

[0009] The segment ring according to the present invention has a plurality of segment pieces configured as described above, and the plurality of segment pieces are arranged in a ring shape and connected to each other in the circumferential direction.

[0010] The tunnel lining structure according to the present invention has a plurality of segment rings configured as described above, and the plurality of segment rings are continuously connected in the extending direction of the tunnel.

Effect of the Invention

[0011] The segment piece of the present invention has a plurality of inner circumferential side compression steel materials and a plurality of outer circumferential side compression steel materials having a cover thickness equal to or greater than that of the distribution reinforcement. With this configuration, in the radial direction of the segment ring, the compression steel materials are arranged on the end side of the segment piece. That is, the compression steel materials are arranged at the outer end of the segment piece in the radial direction of the segment ring. Since the segment piece can ensure the strength of the segment piece as the steel material is arranged at the outer end like the main reinforcement, the segment piece having the above configuration can reduce the generated stress of the concrete.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0013] Hereinafter, the segment piece 10, segment ring 100, tunnel lining structure 200, etc. according to the embodiment will be described with reference to the drawings and the like. In the following drawings including FIG. 1, the relative dimensional relationships and shapes of each component may be different from the actual ones. Also, in the following drawings, those with the same reference numerals are the same or corresponding ones, and this shall be common throughout the entire specification. In addition, terms indicating directions (for example, up, down, left, right, front, back, front and back, etc.) are appropriately used for easy understanding, but their notations are for convenience of explanation and do not limit the arrangement, direction, and orientation of the device, instrument, or component, etc.

[0014] Embodiment. [Segment Ring 100] FIG. 1 is a conceptual diagram of segment ring 100 according to an embodiment as viewed in the axial direction AD. FIG. 2 is a perspective view conceptually showing segment ring 100 according to an embodiment. Segment ring 100 will be described with reference to FIGS. 1 and 2. Note that the axial direction AD shown in FIGS. 1 and 2 represents the axial direction of segment ring 100, and the circumferential direction CD represents the circumferential direction of segment ring 100. Also, the radial direction RD represents the radial direction of segment ring 100, the Y1 side represents the inner circumferential side of segment ring 100, and the Y2 side represents the outer circumferential side of segment ring 100.

[0015] Segment ring 100 is a structure that covers the excavation face in a construction method such as the shield method. Segment ring 100 is formed in a cylindrical shape. Segment ring 100 is formed, for example, in a cylindrical shape, but is not limited to a cylindrical shape. The tunnel body is constructed by connecting a plurality of segment rings 100 along the direction in which the tunnel extends. More specifically, in the shield method, the tunnel body is constructed by arranging segment rings 100 one by one for one circumference (one ring) of the cross-section of the tunnel. Therefore, segment ring 100 constitutes one unit in the direction in which the tunnel extends in the tunnel body.

[0016] [Segment piece 10] Segment piece 10 is annularly arranged and connected to each other in the circumferential direction CD to form segment ring 100, which is formed in a cylindrical shape that covers the excavation face of the tunnel. Segment ring 100 is divided into a plurality of components in the circumferential direction CD. This component is segment piece 10. Segment piece 10 is formed in an arc shape and a curved shape when viewed from the perspective in the axial direction AD of segment ring 100. A plurality of segment pieces 10 are annularly arranged, and segment ring 100 is formed by connecting adjacent segment pieces 10 to each other. Note that all segment pieces 10 are not necessarily formed to have the same size in the circumferential direction CD.

[0017] FIG. 3 is a conceptual diagram of the segment piece 10 according to the embodiment as viewed in the radial direction RD of the segment ring 100. FIG. 4 is a conceptual diagram of the segment piece 10 as viewed from the cross section taken along line A-A of the segment piece 10 shown in FIG. 3. FIG. 5 is a side view of the segment piece 10 shown in FIG. 3 as viewed in the circumferential direction CD of the segment ring 100. FIG. 5 shows the positional relationship of each component when the segment piece 10 is viewed from the side. Note that in FIG. 5, the components inside the segment piece 10 are represented by dotted lines. FIG. 6 is an enlarged view of the joint portion 12 of the segment piece 10L without the compression steel material 50 installed. In FIGS. 3 to 6, in order to clarify the internal structure of the segment piece 10, the presence of reinforcing bars and compression steel materials arranged inside the concrete is shown in a transmissive manner. The structure of the segment piece 10 will be further described with reference to FIGS. 3 to 6.

[0018] The segment piece 10 has an RC structure (reinforced concrete structure). The segment piece 10 includes a main body portion 20, a plurality of main reinforcing bars 30, a plurality of distribution reinforcing bars 40, and a plurality of compression steel materials 50.

[0019] (Main body portion 20) The main body portion 20 is a block-shaped structure mainly made of concrete. The main body portion 20 is curved in an arc shape when viewed from the axial direction AD of the segment ring 100. The main body portion 20 is a three-dimensional structure in which an arcuate plane having a width in the radial direction RD is continuously formed in the axial direction AD. In other words, the main body portion 20 is a rectangular parallelepiped curved in an arc shape.

[0020] The main body portion 20 includes an inner peripheral side wall portion 20a that forms the wall surface on the inner peripheral side (Y1 side) of the segment ring 100, and an outer peripheral side wall portion 20b that forms the wall surface on the outer peripheral side (Y2 side) of the segment ring 100. The inner peripheral side wall portion 20a forms the internal space of the tunnel. The outer peripheral side wall portion 20b constitutes the wall on the outer peripheral side (Y2 side) of the tunnel and forms the side surface disposed along the excavation surface of the tunnel.

[0021] The main body portion 20 has an axial end face 20c that constitutes the wall surface of one end portion and an axial end face 20d that constitutes the wall surface of the other end portion in the axial direction AD of the segment ring 100. The axial end face 20c and the axial end face 20d constitute a vertical cross-section with respect to the direction in which the tunnel extends. The tunnel lining body 200 described later is formed by the axial end face 20c and the axial end face 20d coming into contact with each other and the segment rings 100 being connected to each other.

[0022] The main body portion 20 has a circumferential end face 20e that constitutes the wall surface of one end portion and a circumferential end face 20f that constitutes the wall surface of the other end portion in the circumferential direction CD of the segment ring 100. The segment ring 100 is formed by connecting the circumferential end face 20e and the circumferential end face 20f and the segment pieces 10 being connected to each other.

[0023] At least one seal groove 23 in which a seal member is disposed is formed in the axial end face 20c, the axial end face 20d, the circumferential end face 20e, and the circumferential end face 20f of the main body portion 20. The seal groove 23 is formed so as to be recessed toward the inner side of the main body portion 20. The seal grooves 23 formed in the circumferential end face 20e and the circumferential end face 20f are formed so as to extend in the axial direction AD of the segment ring 100. The seal grooves 23 formed in the axial end face 20c and the axial end face 20d are formed so as to extend in the circumferential direction CD of the segment ring 100. The main body portion 20 has at least the seal groove 23 formed on the outer peripheral side (Y2 side) in the radial direction RD of the segment ring 100. The main body portion 20 may further have the seal groove 23 formed on the inner peripheral side (Y1 side) in the radial direction RD of the segment ring 100. A seal member (not shown) is mounted in this seal groove 23. The seal member is, for example, a water-swellable sealing material, but is not limited to a water-swellable sealing material.

[0024] (Main reinforcement 30) A plurality of main reinforcement bars 30 are embedded inside the main body portion 20 as main steel materials, and are arranged to extend in the circumferential direction CD of the segment ring 100. The main reinforcement bars 30 are, for example, steel bars. The segment piece 10 shown in FIGS. 3 to 5 has nine main reinforcement bars 30 along the axial direction AD of the segment ring 100 and two main reinforcement bars 30 along the radial direction RD of the segment ring 100, but the number of main reinforcement bars 30 is not limited to this number.

[0025] The main reinforcement bars 30 include at least a plurality of inner circumferential side main reinforcement bars 31 arranged along the axial direction AD of the segment ring 100 and disposed at the innermost circumference in the radial direction RD, and a plurality of outer circumferential side main reinforcement bars 32 arranged along the axial direction AD and disposed at the outermost circumference in the radial direction RD.

[0026] As shown in FIGS. 3 and 4, the length of the main reinforcement bar 30 in the circumferential direction CD is shorter than the length of the main body portion 20 in the circumferential direction CD. Therefore, as shown in the segment piece 10L of FIG. 6, intervals are respectively provided between both ends of the main reinforcement bar 30 and the circumferential end faces 20e and 20f of the main body portion 20. That is, the main reinforcement bar 30 does not extend to the joint portion 12 which is the end of the main body portion 20 and where the segment pieces 10 are connected to each other.

[0027] (Distribution reinforcement bars 40) The distribution reinforcement bars 40 are embedded inside the main body portion 20, are arranged to extend in the radial direction RD and the axial direction AD of the segment ring 100, and restrain a plurality of main reinforcement bars 30. The distribution reinforcement bars 40 are hoop bars that restrain the main reinforcement bars 30 and are strip bars. The distribution reinforcement bars 40 surround and restrain the inner circumferential side main reinforcement bars 31 and the outer circumferential side main reinforcement bars 32 from the outside. A plurality of distribution reinforcement bars 40 are provided in the extending direction of the main reinforcement bars 30. The segment piece 10 shown in FIGS. 3 to 5 has nine distribution reinforcement bars 40 along the circumferential direction CD of the segment ring 100, but the number of distribution reinforcement bars 40 is not limited to this number.

[0028] (Compression steel materials 50) The compression steel material 50 is embedded so as to extend from the circumferential end faces 20e and 20f, which are the end faces in the circumferential direction CD of the main body part 20, toward the central part 20h inside the main body part 20. The compression steel material 50 is embedded inside the main body part 20 as a reinforcing steel material. In the segment ring 100, the compressive force generated between adjacent segment pieces 10 is transmitted to the compression steel material 50, and the force transmitted to the compression steel material 50 is dispersed from the compression steel material 50 to the surrounding concrete.

[0029] The compression steel material 50 is formed in a bar shape. The compression steel material 50 is, for example, a reinforcing bar and is a deformed bar. The segment piece 10 shown in FIGS. 3 to 5 has eight compression steel materials 50 along the axial direction AD of the segment ring 100 and two compression steel materials 50 along the radial direction RD of the segment ring 100, but the number of the compression steel materials 50 is not limited to this number.

[0030] FIG. 7 is an enlarged view of the joint part 12 of the segment piece 10 in which the compression steel material 50 is installed. The compression steel material 50 has at least one of a plurality of inner circumferential side compression steel materials 51 arranged on the inner circumferential side (Y1 side) in the radial direction RD and a plurality of outer circumferential side compression steel materials 52 arranged on the outer circumferential side (Y2 side) in the radial direction RD.

[0031] The plurality of inner circumferential side compression steel materials 51 and the plurality of outer circumferential side compression steel materials 52 have a cover thickness equal to or greater than that of the plurality of force distribution bars 40 in the radial direction RD. That is, as shown in FIG. 7, the cover thickness T1 of the inner circumferential side compression steel material 51 arranged on the inner circumferential side (Y1 side) of the segment piece 10 has a thickness equal to or greater than the cover thickness T2 of the force distribution bar 40 on the inner circumferential side (Y1 side) of the segment piece 10. Similarly, the cover thickness T3 of the outer circumferential side compression steel material 52 arranged on the outer circumferential side (Y2 side) of the segment piece 10 has a thickness equal to or greater than the cover thickness T4 of the force distribution bar 40 on the outer circumferential side (Y2 side) of the segment piece 10.

[0032] As shown in Fig. 5, within the region 45 surrounded by at least one of the plurality of force-transferring bars 40 arranged around the plurality of main bars 30, the plurality of inner circumferential compression steel bars 51 are arranged at the innermost circumference in the radial direction RD among the positions where the plurality of compression steel bars 50 can be arranged. Similarly, within the region 45 surrounded by at least one of the plurality of force-transferring bars 40 arranged around the plurality of main bars 30, the plurality of outer circumferential compression steel bars 52 are arranged at the outermost circumference in the radial direction RD among the positions where the plurality of compression steel bars 50 can be arranged. In Fig. 5, the region 45 is shown as the region indicated by the dotted hatching.

[0033] Also, as shown in Fig. 5, each of the plurality of inner circumferential compression steel bars 51 is arranged at least partially between the plurality of inner circumferential main bars 31 in the axial direction AD. Also, each of the plurality of outer circumferential compression steel bars 52 is arranged at least partially between the plurality of outer circumferential main bars 32 in the axial direction AD.

[0034] Also, as shown in Fig. 5, the plurality of inner circumferential compression steel bars 51 are arranged on the inner circumferential side (Y1 side) of the seal groove 23 formed on the innermost circumferential side (Y1 side). Also, the plurality of outer circumferential compression steel bars 52 are arranged on the outer circumferential side (Y2 side) of the seal groove 23 formed on the outermost circumferential side (Y2 side). It is desirable that the compression steel bars 50 be arranged at the outer end of the main body portion 20 as close as possible in the radial direction RD, but they may be formed so as to reach up to the outside of the two seal grooves 23 adjacent to the two seal grooves 23. Note that the compression steel bars 50 are not limited to this configuration. For example, the plurality of inner circumferential compression steel bars 51 may be arranged on the outer circumferential side (Y2 side) of the seal groove 23 formed on the innermost circumferential side (Y1 side). Also, the plurality of outer circumferential compression steel bars 52 may be arranged on the inner circumferential side (Y1 side) of the seal groove 23 formed on the outermost circumferential side (Y2 side). That is, the plurality of inner circumferential compression steel bars 51 and the plurality of outer circumferential compression steel bars 52 may be arranged between the two seal grooves 23.

[0035] Further, as shown in FIG. 5, in a cross-section along the axial direction AD and the radial direction RD of the main body 20, the thickness in the radial direction RD of the main body 20 is defined as the cross-sectional thickness ST. In this case, the plurality of inner circumferential compression steel materials 51 are arranged within a range from the inner circumferential wall portion 20a to one-third of the cross-sectional thickness ST. Further, the plurality of outer circumferential compression steel materials 52 are arranged within a range from the outer circumferential wall portion 20b to one-third of the cross-sectional thickness ST.

[0036] FIG. 8 is an enlarged view showing an example of the compression steel material 50. The compression steel material 50 has a straight portion 56 extending linearly from the end surface of the circumferential end surface 20e or the circumferential end surface 20f, and an inclined portion 57 provided at the tip end portion 56a of the straight portion 56 and inclined with respect to the extending direction of the straight portion 56.

[0037] The length L of each of the plurality of compression steel materials 50 is formed to be a length of 12 times or more of the bar diameter D in the compression steel material 50. The length L of the compression steel material 50 is the length along the extending direction of the compression steel material 50. Therefore, the length L of the compression steel material 50 is the total length of the length L1 of the straight portion 56 and the length L2 of the inclined portion 57. Since the load that can be borne by the compression steel material 50 varies depending on the cross-sectional area of the diameter, by specifying the length L of the compression steel material 50 based on the magnification with respect to the bar diameter, the force shared by the compression reinforcement is determined, and the force for dispersing the stress applied to the concrete is determined.

[0038] As described above, there has been a structural proposal to install steel materials in the joint portion 12 to reduce the stress burden of the concrete by the concrete and the steel materials. However, in reality, there are no details such as what kind of steel materials should be installed to what depth, and no verification tests have been conducted. The manner of installing the steel materials has been poorly grounded. This time, the inventor conducted a verification test by changing the installation length of the compression steel material 50. The verification test is for verifying how much installation length of the compression steel material 50 is required to reduce the generated stress of the concrete. Note that the installation length of the compression steel material 50 is also the embedding length of the compression steel material 50.

[0039] Fig. 9 is a diagram showing the relationship between the length of the compression steel material 50, the experimental values, and the theoretical values in the RC structure. Fig. 10 is a diagram showing the compression steel material length and the concrete stress (experimental values and theoretical values). The verification test was to confirm the effectiveness of the compression steel material 50 with deformed bars using the length L as a parameter. In the verification test, the bar diameter D was used as the rebar diameter, and the length L of the compression steel material 50 was set in the range of 9 to 15 times the rebar diameter. Specifically, when the length L of the compression steel material 50 was set to 9 times, 12 times, and 15 times the rebar diameter, the stress generated in the concrete was measured. Note that in the verification test, the stress generated when the axial compressive force was 4000 kN and the bending moment was 480 kN·m was measured. The results of the verification test are as shown in Fig. 9 and Fig. 10.

[0040] From the test results, the length L of the compression steel material 50 generally exhibits its effect as per the theoretical values in the RC structure when it is 12 times or more the rebar diameter. Therefore, as a result of the verification test, the inventor confirmed that when using rebar for the compression steel material 50, its effect appears when it is 12 times or more the rebar diameter. Note that the same test was carried out twice in the verification test, and its reproducibility was also confirmed.

[0041] As shown in Figs. 3 to 5, the segment piece 10 may have a plurality of bases 60. The base 60 is formed in a flat plate shape. However, the shape of the base 60 is not limited to being formed in a flat plate shape. The base 60 may be formed, for example, in an angle shape.

[0042] As shown in Fig. 5, the base 60 is arranged in the segment piece 10 so as to be exposed at the circumferential end face 20e and the circumferential end face 20f. Each of the plurality of bases 60 is connected to each of the plurality of compression steel materials 50. Each of the plurality of compression steel materials 50 has an end on the side of the circumferential end face 20e or the circumferential end face 20f connected to the base 60. The base 60 and the compression steel material 50 are fixed by welding. The base 60 is used for positioning when arranging the compression steel material 50 in the main body part 20 and is used in the fabrication when embedding the compression steel material 50 in the concrete of the main body part 20.

[0043] FIG. 11 is a conceptual diagram of the segment piece 10 of the modified example as viewed from the circumferential direction CD of the segment ring 100. The shape of the base 60A of the modified example is different from the shape of the base 60 described above.

[0044] The base 60A is formed in a flat plate shape and is formed in a long shape in the axial direction AD of the segment ring 100. Each of the plurality of bases 60A is connected to a plurality of compression steel materials 50. One end of the plurality of compression steel materials 50 on the circumferential end face 20e or the circumferential end face 20f side is connected to the base 60A. The plurality of compression steel materials 50 are arranged along the longitudinal direction of the base 60A. That is, a plurality of compression steel materials 50 are connected to the base 60A formed in a long shape.

[0045] As shown in FIGS. 4, 5, and 8, the base 60 and the base 60A are exposed from end faces such as the circumferential end face 20e and the circumferential end face 20f, and the exposed surfaces of the base 60 and the base 60A are covered with a waterproof agent 70. The waterproof agent 70 is, for example, an elastic epoxy. The waterproof agent 70 is applied so as to cover the base 60 and the base 60A exposed on the circumferential end face 20e and the circumferential end face 20f.

[0046] [Manufacture of Segment Piece 10] First, a formwork for the main body 20 is created. A base 60 to which a compression steel material 50 is welded is fixed by a fixture such as a bolt at the position of the end of the circumferential direction CD of the main body 20. A steel bar cage formed by the main reinforcement 30 and the distribution reinforcement 40 is arranged in the formwork. Then, concrete is placed in the formwork, and after the concrete solidifies, the segment piece 10 is formed by removing the main body 20 from the formwork.

[0047] [Tunnel Lining Structure 200] FIG. 12 is a conceptual diagram of the tunnel lining structure 200 according to the embodiment. The tunnel lining structure 200 has a plurality of segment rings 100, and the plurality of segment rings 100 are continuously connected in the extending direction of the tunnel. The tunnel lining structure 200 is used, for example, to construct tunnels constituting subways, road tunnels, sewers, power lines, communication ducts, utility tunnels, and the like.

[0048] [Function and Effect of Segment Piece 10] The segment piece 10 has a plurality of inner circumferential compression steel materials 51 and a plurality of outer circumferential compression steel materials 52, which have a cover thickness equal to or greater than that of the distribution bars 40. With this configuration, in the radial direction RD of the segment ring 100, the compression steel material 50 is disposed on the end side of the segment piece 10. That is, the compression steel material 50 is disposed at the outer end of the segment piece 10 in the radial direction RD of the segment ring 100. Since the segment piece 10 can ensure the strength of the segment piece 10 as the steel material is disposed at the outer end, the segment piece 10 having the above configuration can reduce the generated stress of the concrete.

[0049] Also, the plurality of inner circumferential compression steel materials 51 are disposed at the innermost circumference in the radial direction RD among the positions where the plurality of compression steel materials 50 can be disposed, and the plurality of outer circumferential compression steel materials 52 are disposed at the outermost circumference in the radial direction RD among the positions where the plurality of compression steel materials 50 can be disposed. Since the segment piece 10 can ensure the strength of the segment piece 10 as the compression steel material 50 is disposed at the outer end of the segment piece 10, the segment piece 10 having the above configuration can reduce the generated stress of the concrete.

[0050] In the axial direction AD, at least a part of each of the plurality of inner peripheral compression steel materials 51 is disposed between the plurality of inner peripheral main reinforcements 31, and at least a part of each of the plurality of outer peripheral compression steel materials 52 is disposed between the plurality of outer peripheral main reinforcements 32. Since the compression steel material 50 can secure the strength of the segment piece 10 as it is disposed at the outer end of the segment piece 10, the segment piece 10 having the above configuration can reduce the generated stress of the concrete.

[0051] Also, generally, the main reinforcement 30 is arranged at the most advantageous position in the main body portion 20 from the viewpoint of coping with the generated stress of the concrete. With the above configuration, at least a part of the inner peripheral compression steel material 51 and the outer peripheral compression steel material 52 is arranged at a position overlapping the main reinforcement 30 in the axial direction AD. That is, the inner peripheral compression steel material 51 and the outer peripheral compression steel material 52 are arranged at positions substantially equal to the positions where the main reinforcement 30 is arranged in the radial direction RD. Therefore, like the main reinforcement 30, the inner peripheral compression steel material 51 and the outer peripheral compression steel material 52 are arranged at the most advantageous positions in the main body portion 20 from the viewpoint of coping with the generated stress of the concrete. Therefore, the segment piece 10 having the above configuration can reduce the generated stress of the concrete.

[0052] Also, the plurality of inner peripheral compression steel materials 51 are arranged on the inner peripheral side of the seal groove 23 formed on the innermost peripheral side, and the plurality of outer peripheral compression steel materials 52 are arranged on the outer peripheral side of the seal groove 23 formed on the outermost peripheral side. Since the compression steel material 50 can secure the strength of the segment piece 10 as it is disposed at the outer end of the segment piece 10, the segment piece 10 having the above configuration can reduce the generated stress of the concrete.

[0053] Further, the plurality of inner peripheral side compression steel materials 51 are arranged within the range from the inner peripheral side wall portion 20a to one-third of the cross-sectional thickness ST, and the plurality of outer peripheral side compression steel materials 52 are arranged within the range from the outer peripheral side wall portion 20b to one-third of the cross-sectional thickness ST. Since the compression steel material 50 can secure the strength of the segment piece 10 as it is arranged closer to the outer end of the segment piece 10, the segment piece 10 having the above configuration can reduce the generated stress of the concrete.

[0054] Further, each of the plurality of compression steel materials 50 has a straight portion 56 formed linearly, and an inclined portion 57 provided at the tip portion 56a of the straight portion 56 and inclined with respect to the extending direction of the straight portion 56. The main body portion 20 is formed in an arc shape, and if the compression steel material 50 is formed only by the straight portion 56, it may interfere with the distribution reinforcement 40. The compression steel material 50 can avoid interference with the distribution reinforcement 40 by having the inclined portion 57. As a result, the compression steel material 50 can secure the embedment length.

[0055] Further, the length L of each of the plurality of compression steel materials 50 is formed to be 12 times or more the diameter D of the steel bar. Therefore, as described above, the effect along the theoretical value in the RC structure can be exhibited, and the segment piece 10 can reduce the stress generated in the concrete.

[0056] Further, the segment piece 10 has a base portion 60 formed in a flat plate shape, and the plurality of compression steel materials 50 are each connected to the base portion 60. Since the compression steel material 50 is connected to the base portion 60, positioning during the creation of the segment piece 10 becomes easy, and the manufacturability of the segment piece 10 can be improved.

[0057] Further, the plurality of compression steel materials 50 are connected to a base portion 60A, and the plurality of compression steel materials 50 are arranged along the longitudinal direction of the base portion 60A. Since the base portion 60A is connected to the plurality of compression steel materials 50, the positioning of the plurality of compression steel materials 50 can be performed simultaneously. Therefore, the segment piece 10 having the base portion 60A can further improve the manufacturability.

[0058] Further, the bases 60 and 60A are exposed from the end faces, and the exposed surfaces of the bases 60 and 60A are covered with a waterproof agent 70. Generally, water may penetrate into the interface between concrete and steel. By applying the waterproof agent 70 so as to cover the exposed surfaces of the bases 60 and 60A, water penetration can be prevented. As a result, the compression steel bars 50 can be arranged outside the seal groove 23 formed in the segment piece 10 in the radial direction RD.

[0059] The segment ring 100 has the segment piece 10 having the above-described configuration. As a result, the segment ring 100 can obtain the same effects as the segment piece 10 according to the embodiment.

[0060] The tunnel lining 200 has the segment ring 100 having the above-described configuration. As a result, the tunnel lining 200 can obtain the same effects as the segment piece 10 according to the embodiment.

[0061] The configuration shown in the above embodiment is an example, and it is possible to combine it with another known technique, and it is also possible to omit or change a part of the configuration without departing from the gist.

Description of Reference Numerals

[0062] 10 segment pieces, 12 joint parts, 20 main body parts, 20a inner peripheral side wall part, 20b outer peripheral side wall part, 20c axial end face, 20d axial end face, 20e circumferential end face, 20f circumferential end face, 20h central part, 23 seal groove, 30 main reinforcement bars, 31 inner peripheral side main reinforcement bars, 32 outer peripheral side main reinforcement bars, 40 distribution reinforcement bars, 45 within the region, 50 compression steel materials, 51 inner peripheral side compression steel materials, 52 outer peripheral side compression steel materials, 56 straight part, 56a tip part, 57 inclined part, 60 base part, 60A base part, 70 waterproof agent, 100 segment ring, 200 tunnel lining structure, AD axial direction, CD circumferential direction, D bar diameter, RD radial direction, ST cross-sectional thickness, T1 cover thickness, T2 cover thickness, T3 cover thickness, T4 cover thickness.

Claims

1. A segment piece that constitutes a segment ring formed in a cylindrical shape that covers the excavation surface of a tunnel by being arranged annularly and connected to each other in the circumferential direction, a main body portion mainly made of concrete, a plurality of main reinforcement bars embedded inside the main body portion and arranged to extend in the circumferential direction of the segment ring, a plurality of force-retaining bars embedded inside the main body portion and arranged to extend in the radial direction and the axial direction of the segment ring to restrain the plurality of main reinforcement bars, a plurality of compression steel bars embedded so as to extend inward from the circumferential end face of the main body portion toward the central portion and formed in a rod shape, comprising, the plurality of compression steel bars, a plurality of inner circumferential side compression steel bars arranged on the inner circumferential side in the radial direction, a plurality of outer circumferential side compression steel bars arranged on the outer circumferential side in the radial direction, having at least one of them, the plurality of inner circumferential side compression steel bars and the plurality of outer circumferential side compression steel bars, have a cover thickness equal to or greater than that of the plurality of force-retaining bars in the radial direction, each of the plurality of compression steel bars, a straight portion extending from the end face and formed in a straight line, an inclined portion provided at the tip of the straight portion, inclined with respect to the extending direction of the straight portion, and inclined from the outside to the center of the segment piece as viewed in the axial direction from the straight portion toward the tip, A segment piece having.

2. The plurality of main reinforcement bars, a plurality of inner circumferential side main reinforcement bars arranged along the axial direction on the inner circumferential side in the radial direction, a plurality of outer circumferential side main reinforcement bars arranged along the axial direction on the outer circumferential side in the radial direction, having, each of the plurality of inner circumferential side compression steel bars, at least a part thereof is arranged between the plurality of inner circumferential side main reinforcement bars in the axial direction, each of the plurality of outer circumferential side compression steel bars, at least a part thereof is arranged between the plurality of outer circumferential side main reinforcement bars in the axial direction, at least one seal groove in which a seal member is arranged is formed on the end face of the main body portion, the seal groove, is formed so as to be recessed toward the inside of the main body portion and is formed at least on the outer circumferential side so as to extend in the axial direction, when the at least one seal groove is formed only on the outer circumferential side in the radial direction, the plurality of outer circumferential side compression steel bars, are arranged on the outer circumferential side of the seal groove, When the at least one seal groove is a plurality of seal grooves formed on the inner circumferential side and the outer circumferential side in the radial direction, the plurality of inner circumferential side compression steel materials, are disposed on the inner circumferential side of the seal groove formed on the innermost circumferential side, the plurality of outer circumferential side compression steel materials, The segment piece according to claim 1, wherein the segment piece is disposed on the outer circumferential side of the seal groove formed on the outermost circumferential side.

3. the plurality of inner circumferential side compression steel materials, are arranged along the axial direction on the inner circumferential side in the radial direction within a region surrounded by at least one of the plurality of force transmitting bars disposed around the plurality of main bars, the plurality of outer circumferential side compression steel materials, The segment piece according to claim 1 or 2, wherein the segment piece is arranged along the axial direction on the outer circumferential side in the radial direction within a region surrounded by at least one of the plurality of force transmitting bars disposed around the plurality of main bars.

4. the main body portion, an inner circumferential side wall portion that forms the inner circumferential side wall surface of the segment ring, an outer circumferential side wall portion that forms the outer circumferential side wall surface of the segment ring, has, In the cross-sectional thickness that is the radial thickness in the cross-section along the axial direction and the radial direction of the main body portion, the plurality of inner circumferential side compression steel materials, are arranged within a range from the inner circumferential side wall portion to one-third of the cross-sectional thickness, the plurality of outer circumferential side compression steel materials, The segment piece according to any one of claims 1 to 3, wherein the segment piece is arranged within a range from the outer circumferential side wall portion to one-third of the cross-sectional thickness.

5. each of the plurality of compression steel materials, is a deformed steel bar, the length of each of the plurality of compression steel materials, The segment piece according to any one of claims 1 to 4, wherein the segment piece is formed to have a length of 12 times or more the bar diameter.

6. has a plurality of bases disposed on the end face and formed in a flat plate shape, each of the plurality of bases, is connected to each of the plurality of compression steel materials. The segment piece according to any one of claims 1 to 5.

7. has a plurality of bases disposed on the end face and formed in a long and flat plate shape so as to extend in the axial direction, each of the plurality of bases, is connected to the plurality of compression steel materials, the plurality of compression steel materials, The segment piece according to any one of claims 1 to 5, wherein the segment piece is arranged along the longitudinal direction of the plurality of bases.

8. the plurality of bases, The segment piece according to claim 6 or 7, which is exposed from the end face and the exposed surfaces of the plurality of bases are covered with a waterproof agent.

9. Having a plurality of the segment pieces according to any one of claims 1 to 8, A segment ring formed by arranging a plurality of the segment pieces in a ring shape and connecting them to each other in the circumferential direction.

10. Having a plurality of the segment rings according to claim 9, A tunnel lining structure in which a plurality of the segment rings are continuously connected in the extending direction of the tunnel.

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