Segment

Abstract

To provide a segment that can be designed separately and can prevent slippage between a frame body and concrete.SOLUTION: The present invention relates to a segment 100 having a box-shaped frame body with a hollow portion and concrete 20 poured in the hollow portion, in which the frame body has a pair of opposing main girder plates 11, an outer plate 12 welded to outer ends of both main girder plates 11, a bottom plate 13 welded to inner ends of both main girder plates 11, and connecting plates welded to both side ends of both main girder plates 11, the outer plate 12, and the bottom plate 13. An opening 16 extending circumferentially is provided in the bottom plate 13, and the concrete 20 is a convex body having a main body 21 and a protrusion 22 provided on the main body 21, the protrusion 22 being restrained from both sides by the central end portion of the bottom plate 13 on the opening 16 side, a top 22a of the protrusion 22 being exposed from the opening 16.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a segment used in a shield tunneling method, a jacking method, a cut-and-cover tunneling method, and an Urban Ring method (a split-assembly type earth retaining wall construction method). [Background technology]

[0002] The segments are broadly divided into those made of concrete and those made of steel, with the former concrete segments being strong in compression and the latter steel segments being strong in tension. On the other hand, composite segments are used that combine the advantages of concrete and steel segments and have properties that combine these advantages.

[0003] A known example of such a composite segment is one that consists of a frame body 2 made of steel plates, main reinforcing bars (main steel materials) 8 and distribution bars 20 arranged within this frame body 2, and concrete 3 (see Figures 1 and 2) poured inside the frame body 2 so as to bury the main reinforcing bars 8 and distribution bars 20 (see Patent Document 1).

[0004] In addition, a steel shell is formed by a pair of main girders 12, 12 extending in the circumferential direction of the tunnel and located at the entrance-side end face and face-side end face of the composite segment 11, joint plates 13, 13 extending in the direction of the tunnel axis and provided with segment joints, and ground-side steel plates 14a provided on the ground side of these main girders 12, 12 and joint plates 13, 13 and inner space-side steel plates 14b provided on the inner space side of the tunnel, and concrete 17 is filled inside the shell, and a segment is known in which a number of stud dowels 16a, 16b are welded to the inner surfaces of the ground-side steel plates 14a and the space-side steel plates 14b to increase the unity with the filled concrete (see Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5906277 [Patent Document 2] Patent No. 6242784 Summary of the Invention [Problem to be solved by the invention]

[0006] In the segment described in Patent Document 1, the frame body and concrete are integrated by pouring concrete so that the main reinforcing bars and distribution bars inside the frame body are buried, while in the segment described in Patent Document 2, stud dowels are implanted into the frame body (steel shell), and the frame body (steel shell) and concrete are integrated by the stud dowels. In other words, these segments are designed by integrating the frame (steel shell) and concrete.

[0007] On the other hand, if accessories with complex shapes such as main reinforcing bars, distribution bars, stud dowels, etc. are not installed inside the frame, and the frame body and the concrete inside the frame body are not integrated, it is possible to design the two separately. However, there is a drawback in that separating the frame and the concrete makes it easy for misalignment to occur between them. Furthermore, if a gap occurs between the frame and the concrete, the rigidity and strength of the segments may decrease.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a segment that can be designed separately and can prevent slippage between the frame body and the concrete. [Means for solving the problem]

[0009] The inventors conducted research to solve the above problems and discovered that by not integrating the frame body and the concrete, the design related to the concrete and the design related to the frame body could be separated, and further, by directly restraining part of the concrete with part of the frame body, in other words, by creating a structure in which the concrete is restrained by the frame body even when it tries to deform due to strain caused by stress, the above problems could be solved, leading to the completion of the present invention.

[0010] The present invention relates to a segment comprising a box-shaped frame body having a hollow portion and concrete poured into the hollow portion, wherein the frame body has a pair of opposing main girders, an outer plate welded to the outer ends of both main girders, a bottom plate welded to the inner ends of both main girders, and joint plates welded to both side ends of both main girders, the outer plate, and the bottom plate, wherein the bottom plate has an opening extending in the circumferential direction, and the concrete is a convex body having a main body and a protrusion provided on the main body, the protrusion being restrained from both sides by the central end portion on the opening side of the bottom plate, and the top of the protrusion being exposed from the opening.

[0011] In the segment of the present invention, it is preferable that the opening extends from the joint plate on one side to the joint plate on the other side.

[0012] In the segment of the present invention, the opening is preferably provided at the center of the bottom plate in the axial direction, and the size of the opening in the axial direction is preferably 100 to 500 mm.

[0013] In the segment of the present invention, the opening is provided with a connecting portion that connects the central end portion on one side of the opening side of the bottom plate to the central end portion on the other side, and it is preferable that the connecting portion be made of steel or reinforcing bar. Furthermore, when the connecting portion is made of steel, it is more preferable that both ends of the connecting portion are inclined groove portions, and that the connecting portion is welded to the bottom plate on one side and the bottom plate on the other side at a certain root spacing.

[0014] In the segment of the present invention, the bottom plate is preferably provided with a plurality of air vent holes.

[0015] In the segments of the present invention, the concrete is preferably provided with injection or gripping holes extending inwardly from the tops of the projections. [Effects of the Invention]

[0016] The segment of the present invention is designed so that the frame and concrete are not connected and integrated, allowing the concrete design and the frame design to be carried out separately. The design of the segment is a combination of these two. In this case, the influence of voids inside the concrete and the shrinkage of the concrete itself on the frame can be eliminated, thereby simplifying the design. In addition, the degree of freedom in designing the frame and concrete can be increased. Furthermore, because the frame and concrete are separate bodies, there is no need to provide accessories with complex shapes inside the frame for integration. This makes the segment of the present invention easy to manufacture and economical.

[0017] In the segment of the present invention, the protruding portion of the concrete is restrained from both sides by the central end portion of the bottom plate of the frame, which prevents axial displacement between the frame and the concrete. In addition, friction between the central end portion and the protruding portion makes it difficult for the frame and concrete to displace in the circumferential direction.

[0018] In the segment of the present invention, by utilizing the openings provided in the bottom plate, concrete can be poured efficiently into the hollow portion. In this case, by extending the opening from one joint plate to the other joint plate, concrete can be poured quickly, which means that the work time can be significantly reduced. In addition, after assembling the frame, it becomes easy to pour concrete on-site, which is called "in-situ pouring," and this significantly reduces the cost of assembling and transporting the segments.

[0019] In the segment of the present invention, by providing the opening in the center of the bottom plate in the axial direction, pre-hardened concrete can be evenly poured into both main girder plate sides of the hollow portion. In other words, pre-hardened concrete is not excessively unevenly distributed, allowing for smooth concrete pouring. In addition, by setting the size of the opening in the axial direction within the above range, concrete can be poured easily and the bottom plate can exhibit sufficient strength.

[0020] In the segment of the present invention, a connecting portion is provided between the center end portion on one side and the center end portion on the other side, which allows the bottom plate on one side and the bottom plate on the other side to exert stress in cooperation with each other, thereby providing sufficient resistance to applied loads. Furthermore, since the protruding portions of the concrete are restrained by adjacent connecting portions, circumferential displacement between the frame body and the concrete can be further suppressed. In other words, the concrete can be more securely restrained. In this case, by using steel or reinforcing bars as the connecting parts, sufficient strength can be achieved.

[0021] Furthermore, when the connecting portion is made of steel, by making the ends on both sides of the connecting portion into inclined groove portions and welding the connecting portion to the bottom plate on one side and the bottom plate on the other side at a certain root distance, the connecting portion can be attached to the frame body with high strength, even when it is added to the frame body later.

[0022] In the segment of the present invention, by providing multiple air vent holes, concrete can be poured in quickly and it is also possible to check whether the concrete has been filled.

[0023] In the segments of the present invention, so-called injection holes or gripping holes are provided directly in the concrete, so they can be easily formed by providing formwork when pouring the concrete. [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 1 is a perspective view showing an embodiment of a segment according to the present invention. [Figure 2] FIG. 2 is an explanatory diagram for explaining the internal structure of the segment shown in FIG. [Figure 3] FIG. 3 is a partial cross-sectional view illustrating welding between a connecting portion and a bottom plate in a segment according to this embodiment. [Figure 4] FIG. 4 is a partial cross-sectional view illustrating welding of object A and object B in the segment according to this embodiment. [Figure 5] FIG. 5 is a cross-sectional view of the segment shown in FIG. 1 taken along line XX. [Figure 6] 6 is a cross-sectional view of the segment shown in FIG. 1, taken along line YY, in which a gripping hole is provided. [Figure 7] FIG. 7 is a cross-sectional view of the segment shown in FIG. 1, taken along line YY, in which an injection hole is provided. [Figure 8] (a) of Figure 8 is an explanatory diagram for explaining the internal structure of a segment according to another first embodiment, (b) of Figure 8 is a cross-sectional view of a segment according to another second embodiment cut in the width direction, (c) of Figure 8 is a cross-sectional view of a segment according to another third embodiment cut in the width direction, (d) of Figure 8 is a cross-sectional view of a segment according to another fourth embodiment cut in the width direction, and (e) of Figure 8 is a cross-sectional view of a segment according to another fifth embodiment cut in the width direction. DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant explanations will be omitted. Furthermore, unless otherwise specified, the positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0026] The segments according to the present invention are used, for example, as pieces for constructing cylindrical shield walls in tunnels. In this case, the segments are connected to each other by joint plates in the circumferential direction of the shield cylindrical wall, and by main girders in the axial direction of the shield cylindrical wall. This process is repeated to form the shield cylindrical wall.

[0027] Here, in this specification, "circumferential direction" means the length direction of the segment (circumferential direction of the shield cylindrical wall), "axial direction" means the width direction of the outer plate and bottom plate of the segment (axial direction of the shield cylindrical wall), and "inner-outer direction" means the thickness direction of the segment. Additionally, "inside" refers to the hollow side of the tunnel from the perspective of the segment, and "outside" refers to the opposite side. In addition, "applied load" refers to loads that are constantly acting, including "vertical and horizontal earth pressure," "water pressure," "ground reaction," and "weight of the lining," as well as "surface load," "load during construction," and "earthquake load."

[0028] FIG. 1 is a perspective view showing an embodiment of a segment according to the present invention. As shown in FIG. 1, a segment 100 according to this embodiment includes a box-shaped frame 10 having a hollow portion, and concrete (not shown) poured into the hollow portion. The segment 100 has a gently curved arch shape, and the thickness in the inner and outer directions is approximately constant from one joint plate 14 to the other joint plate 14.

[0029] FIG. 2 is an explanatory diagram for explaining the internal structure of the segment shown in FIG. As shown in Figure 2, in the segment 100, the frame body 10 has a pair of opposing main girder plates 11, an outer plate 12 welded to the outer ends of both main girder plates 11, a bottom plate 13 welded to the inner ends of both main girder plates 11, joint plates 14 (see Figure 1) welded to both side ends of both main girder plates 11, the outer plate 12 and the bottom plate 13, and a connecting portion 15 provided in an opening 16 in the bottom plate 13. In the segment 100 shown in FIG. 2, the hollow portion of the frame 10 is filled with concrete 20.

[0030] Here, from the viewpoint of strength, steel is preferably used as the material for the main girder plates 11, the outer plates 12, the bottom plates 13, and the joint plates 14. In other words, the segments 100 are preferably concrete-filled steel segments using frames 10 (steel shells) made of steel. Regarding the type of steel, a material that fully satisfies the strength required for the design should be selected. Furthermore, the main girder plates 11, the outer plates 12, the bottom plates 13 and the joint plates 14 may be of the same type or different types as long as they can be welded to each other.

[0031] The main girder plate 11 is an arc-shaped plate. In addition, in the main girder plate 11, the end on the convex side is called the outer end, and the end on the concave side is called the inner end. In the segment 100, a pair of main girders of the same shape are arranged facing each other in the same direction. In the shield tunneling method, the main girder plate 11 is connected to the main girder plate of the adjacent segment in a known manner. The main girder 11 may be processed to be connected to the front side, thereby forming a cylindrical shield wall in the axial direction. The dimensions of the main girder 11, such as width (length in the inward and outward directions), thickness (length in the axial direction), curvature (degree of curve), etc., can be set appropriately depending on the size of the cylindrical shield wall.

[0032] The outer plate 12 is an arch-shaped plate curved along the outer edge of the main girder plate 11. In the segment 100, the ends of the outer plates 12 on the main girder plate 11 side are welded to the outer ends of the main girder plates 11. Details of this welding will be described later. As a result, the outer plate 12 is disposed on the natural ground side of the cylindrical shield wall. The dimensions of the outer plate 12, such as width (axial length), thickness (inner / outer length), curvature (degree of curve), etc., can be set appropriately depending on the size of the cylindrical shield wall.

[0033] The bottom plate 13 is an arch-shaped plate curved along the inner edge of the main girder plate 11. In the segment 100, the ends of the bottom plate 13 on the main girder plate 11 side are welded to the inner ends of the main girder plates 11. Details of this welding will be described later. As a result, the bottom plate 13 is parallel to the outer plate 12 and is disposed on the inner space side of the cylindrical shield wall.

[0034] In the segment 100, an opening 16 is provided in the bottom plate 13, extending in the circumferential direction from the joint plate 14 on one side to the joint plate 14 on the other side. That is, the bottom plate 13 is divided by the opening 16 into a bottom plate on one side (hereinafter also referred to as the "first bottom plate 13a" for convenience) and a bottom plate on the other side (hereinafter also referred to as the "second bottom plate 13b" for convenience). The dimensions of the first bottom plate 13a and the second bottom plate 13b, such as width (axial length), thickness (inward / outward length), curvature (degree of curve), etc., can be set appropriately depending on the size of the shield cylindrical wall.

[0035] As described above, the bottom plate 13 has the opening 16 formed therein, and by utilizing the opening 16, it becomes possible to efficiently pour concrete into the hollow portion. Furthermore, since the opening 16 extends from the joint plate 14 on one side to the joint plate 14 on the other side, concrete can be poured quickly and efficiently. In addition, so-called on-site casting becomes easy, and in this case, the assembly costs and transportation costs of the segments 100 can be significantly reduced.

[0036] Here, it is preferable that the axial length of the first bottom plate 13a and the axial length of the second bottom plate 13b are substantially the same. That is, it is preferable that the opening 16 is provided in the axial center of the entire bottom plate 13. In this case, it becomes possible to allow pre-hardened concrete to flow evenly into both main girder plate 11 sides of the hollow portion.

[0037] In the bottom plate 13, when the thickness (length in the inner and outer directions) of the first bottom plate 13a and the second bottom plate 13b is t, it is preferable that the width (length in the axial direction) of each of the first bottom plate 13a and the second bottom plate 13b is 25 × t or less. In this case, concrete can be easily poured and the bottom plate can exhibit sufficient strength. In addition, when the plate thickness is thin and the hollow portion is too wide compared to the segment width, it may be possible to exceed 25t so that only the necessary gap can be formed.

[0038] Both the first bottom plate 13a and the second bottom plate 13b have a plurality of air vent holes 17 at regular intervals at the end on the main girder plate 11 side. By releasing air through the air vent hole 17, concrete can be poured in quickly, and filling of the concrete can also be confirmed through the air vent hole 17.

[0039] The size of the opening 16 in the axial direction is preferably 100 mm to 500 mm. If the size of the opening 16 is less than 100 mm, it will be more difficult to pour concrete than when the size of the opening 16 is within the above range, and the location of the injection hole or gripping hole described below will be limited, and it may be difficult to install them. On the other hand, if the size of the opening 16 exceeds 500 mm, the axial size of the first bottom plate 13a and the second bottom plate 13b will be smaller than when the size of the opening 16 is within the above range, and the strength of the bottom plate 13 may become insufficient.

[0040] The connecting portion 15 is provided so as to bridge the central end portion of the first bottom plate 13a on the opening 16 side and the central end portion of the second bottom plate 13b on the opening 16 side. From the viewpoint of strength, steel or reinforcing bars are preferably used for the connecting portion 15. In the segment 100, by providing the connecting portion 15 that connects the first bottom plate 13a and the second bottom plate 13b, it becomes possible to exert stress by linking the first bottom plate 13a and the second bottom plate 13b, thereby providing sufficient resistance to the applied load.

[0041] Furthermore, a plurality of connecting portions 15 are provided in opening 16 at regular intervals. The width (circumferential length) of the connecting portion 15 and the circumferential distance between adjacent connecting portions 15 may be determined appropriately based on the relationship between the segment width (axial length) and the thickness of the bottom plate. In this case, the strength of the first bottom plate 13a and the second bottom plate 13b can be improved by connecting them without interfering with the injection of concrete into the hollow portion or the formation of the injection hole or gripping hole described below.

[0042] FIG. 3 is a partial cross-sectional view illustrating welding between a connecting portion and a bottom plate in a segment according to this embodiment. When the connecting portion 15 is a plate-shaped steel material, it is preferable that both end portions 15a on both sides of the connecting portion 15 are inclined groove portions, and that the connecting portion 15 is groove-welded to the first bottom plate 13a and the second bottom plate 13b at a constant root spacing M. In this case, even if the weld is attached to the frame 10 later, by deliberately selecting groove welding among the welding methods, the strength of the welded portion can be made excellent. In this case, from the viewpoint of further improving strength, the root spacing M is preferably set to 1 to 3 mm, and the inclination angle θ of the inclined groove portion is preferably set to 30 to 50°.

[0043] On the other hand, when the connecting portions 15 are made of reinforcing bars, it is preferable that the connecting portions 15 have a diameter of 16 mm or more and are provided at regular intervals. The diameter and number of reinforcing bars are determined based on the width of the hollow portion and the thickness of the bottom plate 13. Furthermore, the reinforcing bars may be welded to the first bottom plate 13a and the second bottom plate 13b on the inner surface side via welded joints, for example.

[0044] Returning to Fig. 1, the joint plates 14 are plates provided on both sides of the segment 100. The joint plates 14 on both sides have the same shape. In the shield tunneling method, the joint plates 14 are connected to the joint plates of adjacent segments by a known method. The joint plates 14 may be processed on the front side for connection. This forms the cylindrical shield wall in the circumferential direction. The size of the joint plate 14, such as its thickness (length in the circumferential direction), can be set appropriately according to the size of the cylindrical shield wall.

[0045] The joint plates 14 are welded to both side ends of both main girders 11, the outer plate 12 and the bottom plate 13, respectively. Therefore, in the segment 100, the main girder plate 11 is welded to the outer plate 12 and the bottom plate 13, and the joint plate 14 is welded to the main girder plate 11, the outer plate 12 and the bottom plate 13.

[0046] FIG. 4 is a partial cross-sectional view illustrating welding of object A and object B in the segment according to this embodiment. (1) When object A is the outer plate 12 and object B is the main girder plate 11 In the segment 100, the end of the outer plate 12 on the main girder plate 11 side is a first groove inclined portion, and the outer plate 12 and the main girder plate 11 are groove welded together with a fixed first root spacing. In addition, tack welds 18 are provided on the inside of the welded corners before groove welding to ensure the positional accuracy of the outer plate 12 and the main girder plate 11. (2) When object A is the outer plate 12 and object B is the joint plate 14 In the segment 100, the end of the outer plate 12 on the joint plate 14 side is a second groove inclined portion, and the outer plate 12 and the joint plate 14 are groove welded together with a constant second root spacing. Furthermore, before groove welding, tack welds 18 are provided on the inside of the welded corners to ensure positional accuracy between the outer plate 12 and the joint plate 14. (3) When object A is the first bottom plate 13a or the second bottom plate 13b and object B is the main girder plate 11 In the segment 100, the end of the first bottom plate 13a or the second bottom plate 13b on the main girder plate 11 side is a third groove inclined portion, and the first bottom plate 13a or the second bottom plate 13b and the main girder plate 11 are groove welded at a fixed third root spacing. Furthermore, tack welds 18 are provided on the inside of the welded corners before groove welding to ensure the positional accuracy between the first bottom plate 13a or the second bottom plate 13b and the main girder plate 11. (4) When the object A is the first bottom plate 13a or the second bottom plate 13b and the object B is the joint plate 14 In the segment 100, the end of the first bottom plate 13a or the second bottom plate 13b on the joint plate 14 side is a fourth groove inclined portion, and the first bottom plate 13a or the second bottom plate 13b and the joint plate 14 are groove welded at a constant fourth root spacing. Furthermore, tack welds 18 are provided on the inside of the welded corners before groove welding to ensure positional accuracy between the first bottom plate 13a or the second bottom plate 13b and the joint plate 14. (5) When object A is the main girder plate 11 and object B is the joint plate 14 In the segment 100, the end of the main girder plate 11 on the joint plate 14 side is a fifth groove inclined portion, and the main girder plate 11 and the joint plate 14 are groove welded together at a fixed fifth root spacing. In addition, before groove welding, tack welds 18 are provided on the inside of the welded corners to ensure positional accuracy between the main girder plate 11 and the joint plate 14.

[0047] In this way, in the segment 100, by selecting groove welding among the welding methods for each welding, it is possible to make the strength of the welded portion excellent. The first to fifth root spacings and the inclination angles of the first to fifth groove inclined portions are all the same as the root spacings and the inclination angles of the groove inclined portions in the welding between the connecting portion and the bottom plate described above.

[0048] Returning to FIG. 2, concrete 20 is poured into the hollow portion of the frame 10 . Here, the frame 10 and the concrete 20 are separate bodies and are not integrated and are not connected to each other. In other words, there are no complicated accessories to be embedded in the concrete 20. This makes it possible to carry out the design for the concrete 20 separately from the design for the frame 10. The design for the segments is a combination of these.

[0049] As a result, the influence of voids inside the concrete 20 and the shrinkage of the concrete 20 itself on the framework 10 can be eliminated, allowing for simplification of the design. Furthermore, the degree of freedom in designing the frame 10 and the concrete 20 can be increased. Furthermore, since there is no need to provide accessories with complex shapes for integration inside the frame body 10, it is easy to manufacture and economical.

[0050] FIG. 5 is a cross-sectional view of the segment shown in FIG. 1 taken along line XX. As shown in FIG. 5, in the segment 100, the concrete 20 is a convex body having a main body 21 and a protrusion 22 provided on the main body 21. The main body 21 is housed in the frame 10, and the top 22a of the protruding portion 22 is exposed from the opening 16.

[0051] The main body 21 is not connected to the main girder plates 11, the outer plates 12, and the bottom plates 13 (the first bottom plate 13a and the second bottom plate 13b) of the frame body 10. The protrusion 22 is not connected to the bottom plate 13, but is restrained on both sides by the central end portion on the opening 16 side of the first bottom plate 13a and the central end portion on the opening 16 side of the second bottom plate 13b. Furthermore, the protrusions 22 are not connected to the above-mentioned connecting portions 15 either, but are restrained by adjacent connecting portions. As a result, the occurrence of misalignment between the frame body 10 and the concrete 20 in the axial and circumferential directions is suppressed. That is, in the segment 100, the frame body 10 and the concrete 20 are not connected to each other, and the concrete 20 is provided with a protrusion 22, thereby preventing the concrete 20 from shifting relative to the frame body 10.

[0052] Next, a case where the segment is provided with a gripping hole 30 or an injection hole 31 will be described. 6 is a cross-sectional view of the segment shown in FIG. 1, taken along line YY, in which a gripping hole is provided. 6, a cylindrical gripping hole 30 is provided in the center of the concrete 20. The gripping hole 30 is a hole for gripping by an assembly device when assembling segments in the shield tunneling method. In the segment 100, the frame 10 is not processed, and the gripping holes 30 are provided only in the concrete 20. Therefore, the gripping holes 30 can be easily formed by providing a formwork when pouring the concrete 20 . Furthermore, it is possible to later form the gripping holes 30 in accordance with the assembly device.

[0053] FIG. 7 is a cross-sectional view of the segment shown in FIG. 1, taken along line YY, in which an injection hole is provided. As shown in Figure 7, a cylindrical injection hole 31 is provided in the center of the concrete 20, penetrating from the inner space side to the natural ground side. The injection hole 31 is a hole for injecting backfill material. In some cases, the injection hole 31 also serves as a gripping hole for gripping the segments by an assembly device when assembling the segments. Such injection holes 31 can be easily formed by providing a formwork when pouring the concrete 20 . In this case, holes must be provided in the outer panel 12 at positions corresponding to the injection holes 31 . In the segment 102 shown in Fig. 8(b) described below, the outer plate 12 also has an opening 26, so there is no need to provide a hole in the outer plate by utilizing the opening 26. In this case, the frame body does not need to be processed, and the injection hole 31 can be formed only in the concrete 20.

[0054] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

[0055] In the segment 100 according to this embodiment, the connecting portion 15 is provided at the opening 16 of the bottom plate 13, but the connecting portion 15 is not essential. 8(a) is an explanatory diagram for explaining the internal structure of a segment according to another embodiment 1. The appearance of the segment 101 according to the first embodiment is the same as that of the segment 100 according to this embodiment shown in FIG. As shown in FIG. 8(a), the segment 101 is the same as the segment 100 according to this embodiment, except that it does not have the connecting portion 15. Even in this case, the friction between the center end and the protruding portion makes it difficult for the protruding portion to come off in the circumferential direction.

[0056] In the segment 100 of this embodiment, concrete 20 is poured into the hollow portion of the frame body 10, but in addition to concrete 20, synthetic resin or the like may also be poured into the hollow portion to fill the gaps.

[0057] In the segment 100 of this embodiment, the bottom plate 13 has an opening 16 extending circumferentially from the joint plate 14 on one side to the joint plate 14 on the other side, but the opening 16 does not necessarily have to extend continuously and may be provided partially. In this case, the shape of the opening may be rectangular, elliptical, or the like when viewed from the front.

[0058] In the segment 100 according to this embodiment, a plurality of air vent holes 17 are provided in the first bottom plate 13a and the second bottom plate 13b, but the number, shape, and location of the holes are not limited to those shown in FIG. 2.

[0059] In the segment 100 according to this embodiment, groove welding is used for welding, but fillet welding or the like may also be used.

[0060] In the segment 100 according to this embodiment, the opening 16 is provided only in the bottom plate 13, but the present invention is not limited to this. Fig. 8(b) is a cross-sectional view of a segment according to another embodiment 2 cut in the width direction, where the cross section shown in Fig. 8(b) is at the same position as the cross section cut along line XX in Fig. 1. As shown in FIG. 8(b), the segment 102 may also have an opening 26 provided in the outer plate 12a. The position and shape of the opening 26 in the outer plate 12a are preferably the same as those of the opening 16 in the bottom plate 13 described above.

[0061] In the segment 100 of this embodiment, the main body 21 of the concrete 20 is not connected to the main girder plate 11, outer plate 12, and bottom plate 13 (first bottom plate 13a and second bottom plate 13b) of the frame body 10, but the frame body 10 and the concrete 20 may be partially connected to the extent that it does not significantly affect the design. Fig. 8(c) is a cross-sectional view of a segment according to another third embodiment taken in the width direction, where the cross section shown in Fig. 8(c) is taken at the same position as the cross section taken along line XX in Fig. 1. 8(c), the segment 103 has flanges 19a extending inward from the frame body at the central end portions of the first bottom plate portion 13a and the second bottom plate portion 13b, so that the main body is partially connected to the frame body via the flanges 19a.

[0062] Fig. 8(d) is a cross-sectional view of a segment according to another fourth embodiment taken in the width direction, where the cross section shown in Fig. 8(d) is at the same position as the cross section taken along line XX in Fig. 1. As shown in Figure 8(d), the segment 104 has a flange 19b extending inward from the frame body at the center of the inner surface of the main girder plate 11. This allows the main body to be partially connected to the frame body via the flange 19b.

[0063] FIG. 8(e) is a cross-sectional view of a segment according to a fifth alternative embodiment cut in the width direction. The cross section shown in FIG. 8(e) is at the same position as the cross section taken along line XX in FIG. 8(e), in the segment 105, flanges 19a extending inwardly of the frame body are provided at the center ends of the first bottom plate portion 13a and the second bottom plate portion 13b of the segment 102 according to the second embodiment, and flanges 19c extending inwardly of the frame body are provided at the center ends of one outer plate 12a and the other outer plate, respectively. As a result, the main body is partially connected to the frame body via the flanges 19a and 19c.

[0064] The segment 100 according to this embodiment has an overall arc shape, but may also have a linear shape (rectangular parallelepiped shape). In this case, a pair of opposing main girders are rectangular in shape. In this case, the segments can be used in tunnels with rectangular cross sections (shielded rectangular tube walls). In this case, the "circumferential direction" means the length direction of the segment (the circumferential direction of the shield rectangular tube wall). [Industrial Applicability]

[0065] The present invention is used as a segment for use in the shield tunneling method, jacking method, cut-and-cover tunneling method, and Urban Ring method (a split-assembly type earth retaining wall construction method). For example, it is used as a piece for constructing a cylindrical shield wall in a tunnel. The segments of the present invention allow for separate design and can prevent misalignment between the frame body and the concrete. [Explanation of symbols]

[0066] 10...Frame 100, 101, 102, 103, 104, 105... segments 11. Main girder plate 12, 12a... Outer panel 13...bottom plate 13a...1st bottom plate 13b...Second bottom plate 14. Joint plate 15...Connection part 15a...end 16,26... opening 17. Air vent hole 18. Tack welding 19a, 19b, 19c... Flanges 20. Concrete 21 Main body 22...Protrusion 22a...top 30...Gripping hole 31...Injection hole M···Root spacing

Claims

1. A segment having a box-shaped frame body having a hollow portion and concrete poured into the hollow portion, the frame body has a pair of opposing main girders, skin plates welded to outer ends of both of the main girders, bottom plates welded to inner ends of both of the main girders, and joint plates welded to both side ends of both of the main girders, the skin plates, and the bottom plates, The bottom plate has an opening extending in a circumferential direction, The concrete is a convex body having a main body and a protrusion provided on the main body, The protrusion is restrained from both sides by a central end portion of the bottom plate on the opening side, A segment in which the top of the protrusion is exposed from the opening.

2. 2. The segment of claim 1, wherein the opening extends from one joint plate to the other joint plate.

3. The opening is provided at the center of the bottom plate in the axial direction, The segment according to claim 1, wherein the size of the opening in the axial direction is 100 to 500 mm.

4. The opening is provided with a connecting portion that is connected to a central end portion on one side of the bottom plate facing the opening and a central end portion on the other side of the bottom plate, The segment according to claim 1, wherein the connecting portion is made of steel or reinforcing bar.

5. If the connecting portion is made of steel, A segment as described in claim 4, wherein both ends of the connecting portion are beveled groove portions, and the connecting portion is welded to the bottom plate on one side and the bottom plate on the other side at a constant root distance.

6. The segment according to claim 1 , wherein the bottom plate is provided with a plurality of air vent holes.

7. 2. The segment of claim 1, wherein the concrete includes a pouring or gripping hole extending inwardly from the top of the projection.

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