Composite segments and earth retaining structures
The composite segment enhances the rigidity and bonding force of the steel shell by integrating a shear prevention member with circumferential and radial portions, addressing the rigidity issues in existing earth retaining structures.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- JFE METAL PROD & ENG INC
- Filing Date
- 2022-07-20
- Publication Date
- 2026-06-12
AI Technical Summary
Existing composite segments for earth retaining structures, such as those described in Patent Document 1, lack sufficient rigidity to prevent deformation of the steel shell and maintain the integrity of the steel-concrete composite structure, particularly due to the limited contribution of stud dowels or dowel plates in enhancing the steel shell's rigidity.
The composite segment incorporates a shear prevention member with a first portion arranged circumferentially and a second portion arranged radially, integrated with a shape-retaining member and reinforcing member, enhancing the bonding force and rigidity of the steel shell.
This configuration improves the rigidity of the steel shell while ensuring strong bonding between the steel shell and the filler material, effectively preventing deformation and maintaining structural integrity under various loads.
Smart Images
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Abstract
Description
Technical Field
[0001] The present disclosure relates to a synthetic segment for forming an earth retaining structure buried in the ground.
Background Art
[0002] Conventionally, synthetic segments for forming earth retaining structures such as shafts or tunnels are known. A synthetic segment has a reinforcing cage disposed inside a steel shell having a main girder forming an axial end face of the earth retaining structure, a joint plate forming a circumferential end face, and a skin plate forming an outer peripheral face, and is formed by filling a filler such as concrete. By integrally forming the steel shell and the filler, the synthetic segment ensures strength and rigidity and can resist the earth pressure from the surrounding ground. Further, the synthetic segment has a displacement preventing structure in order to secure a steel-concrete composite structure. The displacement preventing structure protrudes inside the steel shell.
[0003] For the displacement preventing structure, for example, a stud shear key, PBL (Perfo-Bond Leisten), or a shear connector is used. For example, according to Patent Document 1, as the displacement preventing structure, a stud shear key or a shear plate protrudes inside the steel shell in the axial and radial directions of the earth retaining structure, and is configured such that, by devising the position and shape, a reinforcing cage can be inserted inside the steel shell. Specifically, the stud shear key and the shear plate are provided so as to protrude from the main girder by a predetermined distance, and a space for disposing a reinforcing cage is provided at the central portion inside the steel shell.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] In the composite segment disclosed in Patent Document 1, stud dowels or dowel plates are provided that protrude inward from the main girder, allowing a reinforcing cage to be placed later in the central part of the inside of the steel shell. While the stud dowels or dowel plates function as a shearing stopper between the concrete and the steel shell, they have little effect on the rigidity of the steel shell itself, and there was a problem that they could not suppress deformation that would cause the main girder of the steel shell to collapse.
[0006] This disclosure solves the above-mentioned problems and provides a composite segment and earth retaining structure that suppresses displacement between the steel shell and the filler while improving the rigidity of the steel shell itself. [Means for solving the problem]
[0007] The composite segment according to this disclosure is a composite segment that constitutes a cylindrical body to be buried underground as an earth retaining structure, comprising: a pair of main girders extending in the circumferential direction of the cylindrical body and arranged with their plate surfaces facing each other in the axial direction of the cylindrical body; a pair of joint plates joined to both ends of the pair of main girders in the circumferential direction; a skin plate joined to the outer circumference side of the cylindrical body to a frame formed by the pair of main girders and the pair of joint plates; a shear prevention member joined to each of the pair of main girders and projecting from one main girder toward the other main girder; a shape-retaining member whose longitudinal direction is arranged along the axial direction, joined to the skin plate and projecting radially of the cylindrical body; and a reinforcing member joined to the shear prevention member and the shape-retaining member, wherein the shear prevention member comprises a first portion whose plate surface is arranged along the circumferential direction and a second portion whose plate surface is arranged along the radial direction, and the first portion and the second portion are integrally formed.
[0008] The earth retaining structure of this disclosure is formed by combining a plurality of the above-mentioned composite segments in the circumferential and axial directions. [Effects of the Invention]
[0009] The composite segment of this disclosure improves the rigidity of the steel shell while ensuring the bonding force between the steel shell and the filler material inside it, by connecting the shear-preventing member, which comprises a first portion arranged circumferentially and a second portion arranged radially, with a shape-retaining member and a reinforcing member. [Brief explanation of the drawing]
[0010] [Figure 1] This is a conceptual diagram of the earth retaining structure 200 according to Embodiment 1. [Figure 2] This is a conceptual diagram of the segment ring 150 according to Embodiment 1, viewed in the axial direction AD. [Figure 3] This is a perspective view of an example of a composite segment 100 according to Embodiment 1, as seen from the inner circumference side. [Figure 4] This is a perspective view of an example of a composite segment 100 according to Embodiment 1, as seen from the outer periphery. [Figure 5] This is a plan view showing an example of the internal structure of the composite segment 100 according to Embodiment 1. [Figure 6] This is a side view showing an example of the internal structure of the composite segment 100 according to Embodiment 1. [Figure 7] This is a schematic cross-sectional view showing an example of the internal structure of the composite segment 100 according to Embodiment 1. [Figure 8] This is a perspective view of the steel shell 10 of the composite segment 100 according to Embodiment 1. [Figure 9] This is a perspective view of the steel shell 10 of the composite segment 100 according to Embodiment 1. [Figure 10] Figure 8 is a perspective view showing the steel shell 10 with the reinforcing cage 41 housed inside. [Figure 11] Figure 10 is a perspective view showing the steel shell 10 with the first load-distributing reinforcement bars 48 placed inside. [Figure 12] This is a schematic cross-sectional view showing the internal structure of a modified example of the composite segment 100 according to Embodiment 1. [Figure 13] This is a schematic cross-sectional view showing the internal structure of a modified example of the composite segment 100 according to Embodiment 1. [Figure 14]It is a top view and a side view of a modification of the displacement preventing member 20 of the synthetic segment 100 according to Embodiment 1. [Figure 15] It is a top view and a side view of a modification of the displacement preventing member 20 of the synthetic segment 100 according to Embodiment 1. [Figure 16] It is a top view and a side view of a modification of the displacement preventing member 20 of the synthetic segment 100 according to Embodiment 1.
Mode for Carrying Out the Invention
[0011] Hereinafter, the earth retaining structure and the synthetic segment 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 the respective constituent members may be different from the actual ones. Also, in the following drawings, those denoted by the same reference numerals are the same or corresponding ones, and this shall be common throughout the entire specification. In addition, for the sake of easy understanding, terms indicating directions (for example, up, down, left, right, front, rear, front and back, etc.) are appropriately used, but their notations are for convenience of explanation and do not limit the arrangement, direction and orientation of the device, instrument, or component, etc.
[0012] Embodiment 1. [Earth retaining structure 200] FIG. 1 is a conceptual diagram of the earth retaining structure 200 according to Embodiment 1. The axial direction AD shown in FIG. 1 represents the axial direction of the earth retaining structure 200, and the circumferential direction CD represents the circumferential direction of the earth retaining structure 200. Also, the radial direction RD represents the radial direction of the earth retaining structure 200, the Y1 side represents the inner peripheral side of the earth retaining structure 200, and the Y2 side represents the outer peripheral side of the earth retaining structure 200.
[0013] The earth retaining structure 200 is used, for example, as an earth retaining wall for the lining of a tunnel and is installed on the wall surface of an excavation hole formed by excavating the natural ground. The earth retaining structure 200 is installed underground and is used, as an earth retaining wall, for tunnels that constitute subways, road tunnels, sewers, power lines, communication ducts, utility tunnels, etc., or for shafts, etc. Further, the earth retaining structure 200 may be used as an earth retaining wall for the pressed-in caisson method. When the earth retaining structure 200 is used as an earth retaining wall for the pressed-in caisson method, the earth retaining structure 200 covers the underground excavation surface in a construction method such as the pressing-in method and is submerged in the ground 90.
[0014] The earth retaining structure 200 is formed in a cylindrical shape and has a hollow portion 91. When the earth retaining structure 200 is used as an earth retaining wall for the pressed-in caisson method, the earth retaining structure 200 is arranged in the ground such that the cylindrical axial direction AD becomes the vertical direction.
[0015] The earth retaining structure 200 is formed in a circular shape when viewed in the axial direction AD and is formed in a cylindrical shape as a whole, but is not limited to the cylindrical shape. As long as the earth retaining structure 200 is a cylindrical body, for example, when viewed in the axial direction AD, it may be formed in an oval shape, a rectangular shape, or a square shape with rounded corners, or other shapes. The earth retaining structure 200 has at least one segment ring 150 or has a plurality of segment rings 150, and the plurality of segment rings 150 are continuously connected in the axial direction AD in which the tunnel extends.
[0016] [Segment Ring 150] FIG. 2 is a conceptual diagram of the segment ring 150 according to Embodiment 1 when viewed in the axial direction AD. The segment ring 150 is a structure that covers the underground excavation surface. The segment ring 150 is formed in an annular shape when viewed in the axial direction AD and is formed in a cylindrical shape as a whole. The segment ring 150 is formed, for example, in a cylindrical shape, but is not limited to the cylindrical shape.
[0017] The earth retaining structure 200 is constructed by connecting multiple segment rings 150 at connecting parts 93 along the direction in which the earth retaining structure 200 extends, i.e., along the axial direction AD. The earth retaining structure 200 may also be composed of a single segment ring 150. When the earth retaining structure 200 is used, for example, in a shield tunneling method, the earth retaining structure 200 is constructed by arranging the segment rings 150 around the entire circumference (one ring) of the tunnel's cross-section. Therefore, in the earth retaining structure 200, the segment ring 150 constitutes one unit in the direction in which the tunnel extends.
[0018] The segment ring 150 is divided into multiple composite segments 100 in the circumferential direction CD. That is, multiple composite segments 100 are arranged in a ring, and adjacent composite segments 100 are connected to each other by connecting portions 92 to form the segment ring 150. In Figure 2, the segment ring 150 is shown with composite segments 100 of approximately equal size in the circumferential direction CD, but the size of the composite segments 100 may be formed to be different depending on their installation position in the circumferential direction CD.
[0019] As shown in Figure 1, in the earth retaining structure 200, the segment rings 150 adjacent to each other in the axial direction AD are assembled in such a way that the positions of the composite segments 100 constituting the segment rings 150 are shifted in the circumferential direction CD. More specifically, in the earth retaining structure 200, the composite segments 100 constituting the segment rings 150 are constructed in a staggered arrangement.
[0020] [Composite Segment 100] Figure 3 is a perspective view of an example of the composite segment 100 according to Embodiment 1, viewed from the inner circumference. Figure 4 is a perspective view of an example of the composite segment 100 according to Embodiment 1, viewed from the outer circumference. Figure 5 is a plan view showing an example of the internal structure of the composite segment 100 according to Embodiment 1. Figure 6 is a side view showing an example of the internal structure of the composite segment 100 according to Embodiment 1. Figure 7 is a schematic cross-sectional view showing an example of the internal structure of the composite segment 100 according to Embodiment 1. In order to explain the internal structure of the composite segment 100, the illustration of concrete 80 is partially omitted in Figure 3, and the illustration of concrete 80 is omitted entirely in Figures 5 to 7. Figure 7 is a schematic cross-sectional view shown by line AA in Figure 6. The composite segment 100 will be explained using Figures 3 to 7.
[0021] The composite segments 100 are arranged in a ring and connected to each other in the circumferential direction CD, forming a cylindrical segment ring 150 that covers the excavation surface underground. Multiple composite segments 100 are connected to the retaining structure 200 in the circumferential direction CD and the axial direction AD, thereby constructing the retaining structure 200. The composite segment 100 is a box-shaped structure made by combining multiple steel materials. When viewed in the axial direction AD of the segment ring 150, the composite segment 100 is formed in an arc shape, and as a whole, it is formed in a curved shape.
[0022] The composite segment 100 has a steel shell 10 and concrete 80 filled inside the steel shell 10. The composite segment 100 is a composite structure of a box-shaped steel shell 10 and concrete 80 filled inside the steel shell 10 as a filler, and the steel shell 10 and concrete 80 are integrated into one structure.
[0023] [Reinforcement Unit 40] As shown in Figure 3, the composite segment 100 includes a reinforcing bar unit 40 within the concrete 80. The reinforcing bar unit 40 consists of a reinforcing bar cage 41 and a first distribution reinforcing bar 48. In Embodiment 1, the reinforcing bar cage 41 and the first distribution reinforcing bar 48 are joined together, for example, by welding or binding with wire to form a single unit.
[0024] As shown in Figure 7, the reinforcing cage 41 is formed by joining the main reinforcements 42, 43 and the second distribution reinforcements 45. The main reinforcements 42 extend in the circumferential direction CD and are arranged in multiples with spacing in the axial direction AD. The main reinforcements 43 are also arranged with spacing in the radial direction RD relative to the main reinforcements 42. The main reinforcements 43 also extend in the circumferential direction CD and are arranged in multiples with spacing in the axial direction AD, similar to the main reinforcements 42. Note that the number of main reinforcements 42 and 43 is not limited to multiples and may be one or more. In addition, the reinforcing cage 41 has two rows of main reinforcements 42 and 43 in the radial direction RD, but it may have a single row or three or more rows of main reinforcements.
[0025] As shown in Figures 3 and 5, multiple second reinforcing bars 45 are arranged along the longitudinal direction of the main reinforcing bars 42 and 43, that is, along the circumferential direction CD. As shown in Figure 7, the second reinforcing bar 45 has a main body portion 45a extending along the axial direction AD, an arm portion 45b formed by bending the end of the main body portion 45a in the radial direction RD, and a tip portion 45c formed by bending the tip of the arm portion 45b in the axial direction AD. The second reinforcing bar 45 is formed in a square shape or a square shape with a part of it cut out, so as to surround the rows of main reinforcing bars 42 and 43 from the outside. The second reinforcing bar 45 may be formed by bending a single rod, or it may be formed by combining multiple rods. The second reinforcing bar 45 connects the multiple parallel main reinforcing bars 42 and 43 to form a single reinforcing bar cage 41. Furthermore, the second distribution reinforcement bars 45 may also transmit the load applied to the main reinforcement bars 42 and 43 to adjacent main reinforcement bars 42 and 43, thereby distributing the load. Note that the number of distribution reinforcement bars 45 is not limited to multiple bars; it may be a single bar.
[0026] As shown in Figure 5, the first reinforcing bar 48 is arranged in parallel with the second reinforcing bar 45 in the radial direction RD. The first reinforcing bar 48 is positioned adjacent to the second reinforcing bar 45 and, in combination with the second reinforcing bar 45 which has a shape in which a part of the square shape is cut out, is formed to surround the main reinforcing bars 42 and 43 as shown in Figure 7. However, the first reinforcing bar 48 may be positioned with a gap between it and the second reinforcing bar 45 in the radial direction RD.
[0027] The first reinforcing bar 48 comprises a main body portion 48b extending along the axial direction AD, and insertion portions 48a extending radially RD from both ends of the main body portion 48b. In other words, the first reinforcing bar 48 is formed in a U-shape. Both ends of the main body portion 48b are placed on the shear prevention members 20, which will be described later, and the insertion portions 48a are inserted through through holes 25 provided in the shear prevention members 20. The main body portion 48b of the first reinforcing bar 48 is positioned adjacent to the main reinforcement bars 42 of the reinforcing cage 41.
[0028] [Steel shell 10] As shown in Figures 3 and 4, the steel shell 10 of the composite segment 100 comprises a pair of arc-shaped main girders 11 spaced apart in the axial direction AD and arranged with their plate surfaces facing each other, a pair of joint plates 12 joined to both ends of the main girders 11 in the circumferential direction CD, and skin plates 16 joined to the outer periphery of the main girders 11 and joint plates 12. The steel shell 10 is formed into a box shape by welding these main girders 11, joint plates 12, and skin plates 16 together to form a single unit.
[0029] The pair of main girders 11 are the parts where adjacent composite segments 100 abut each other in the axial AD of the earth retaining structure 200 and the segment ring 150, and are the parts where adjacent composite segments 100 are connected. The pair of main girders 11 are located at both ends of the composite segment 100 in the axial AD of the earth retaining structure 200 and the segment ring 150. That is, the main girders 11 are provided at both ends of the skin plate 16 in the axial AD of the earth retaining structure 200 and the segment ring 150, and form one face and the other face of the composite segment 100 in the axial AD.
[0030] As shown in Figure 6, the main girder 11 is formed in a flat plate shape. The main girder 11 is formed in an arc shape in a plan view in the axial direction AD according to the cross-sectional shape of the tunnel, and is formed in a fan shape that constitutes part of the annular segment ring 150. The plate surface of the main girder 11 extends in the circumferential direction CD and the radial direction RD, and is parallel to the circumferential direction CD and the radial direction RD.
[0031] As shown in Figure 3, one of the pair of main girders 11 has multiple bolt holes 13 formed in it for connecting adjacent composite segments 100 stacked vertically in the axial direction AD. The number of bolt holes 13 is not limited to multiple; it may be one. For example, one bolt hole 13 is formed in the central region and both end regions of the circumferential direction CD where the shear prevention members 20 are not placed. In addition, bolt boxes 81 are provided in the concrete 80 at locations corresponding to the bolt holes 13. The bolt boxes 81 form a space between the concrete 80 and the main girder 11 in the composite segment 100 that exposes the bolt holes 13. The bolt boxes 81 serve as a working space used for fastening bolts to fasten the main girders 11 of adjacent composite segments 100 in the axial direction AD.
[0032] Of the pair of main girders 11, the other main girder 11 has multiple bosses 14 formed thereon for connecting adjacent composite segments 100 stacked vertically in the axial direction AD. The number of bosses 14 is not limited to multiple; it may be one. The bosses 14 have mounting holes with internal threads for threading bolts.
[0033] Two adjacent composite segments 100 in the axial direction AD are joined by butting the main girders 11 together and using bolts. The joining is performed using a bolt box 81, by inserting a bolt into a bolt hole 13 and screwing it into the female thread of a boss 14 provided on the main girder 11 of the adjacent composite segment 100. By screwing the shaft of the bolt inserted into the bolt hole 13 into the female thread of the boss 14 and fastening it, the two adjacent composite segments 100 in the axial direction AD are connected. The number of bolt holes 13 and bosses 14 is not limited to the illustrated example and is determined by considering, for example, the size and shape of the composite segment 100. Note that the connection of adjacent composite segments 100 in the axial direction AD is not limited to a structure connected by bolts and nuts, but may be done by, for example, a one-touch joint, or by using other well-known techniques.
[0034] The pair of joint plates 12 are the parts where adjacent composite segments 100 come into contact with each other in the circumferential direction CD of the earth retaining structure 200 and the segment ring 150, and are the parts where adjacent composite segments 100 are connected. The pair of joint plates 12 are members attached to both ends of the composite segment 100 in the circumferential direction CD.
[0035] The joint plate 12 is formed in a plate shape and consists of a rectangular steel plate. The joint plate 12 is formed to extend in the axial direction AD and the radial direction RD. The joint plate 12 is spanned and fixed between the longitudinal ends of a pair of main girders 11. The longitudinal direction of the main girders 11 is the circumferential direction CD. Joints may be attached to the ends of the composite segments 100 on which the joint plate 12 is located, for connecting the composite segments 100 together to form a single segment ring 150.
[0036] The joint plate 12 is positioned at both ends of the circumferential CD of the composite segment 100 so as to cover the opening formed by the pair of main girders 11 and the skin plate 16 positioned between the pair of main girders 11. The joint plate 12 is provided at both ends of the skin plate 16 in the arc direction and forms the side surface of the circumferential CD of the composite segment 100.
[0037] As shown in Figure 3, the joint plate 12 has multiple bolt holes 15 formed therein for connecting adjacent composite segments 100 arranged in the circumferential direction CD of the excavated hole. The number of bolt holes 15 is not limited to multiple; it may be one. Also, as shown in Figure 3, bolt boxes 82 are provided in the concrete 80 at locations corresponding to the bolt holes 15. The bolt boxes 82 form a space in the composite segment 100 between the concrete 80 and the joint plate 12 that exposes the bolt holes 15. The bolt boxes 82 serve as a working space used for fastening bolts to connect the joint plates 12 of adjacent composite segments 100 in the circumferential direction CD.
[0038] Adjacent composite segments 100 in the circumferential CD direction are connected by butting joint plates 12 together and fastening the shafts of bolts inserted through bolt holes 15 with nuts. The number of bolt holes 15 shown in the illustration is an example and is not limited to this, and is determined by considering, for example, the size and shape of the composite segments 100. Note that the connection of adjacent composite segments 100 in the circumferential CD direction is not limited to a structure connected by bolts and nuts, but may also be done by, for example, a one-touch joint, or by using other well-known techniques.
[0039] The skin plate 16 is a plate-shaped member facing the ground side of the composite segment 100, and is formed by bending a rectangular steel plate into an arc shape in the planar direction. The skin plate 16 is formed in a plate shape with a curved surface. The skin plate 16 is formed to extend in the circumferential direction CD and the axial direction AD. The skin plate 16 is formed in an arc shape when viewed in a plan view in the axial direction AD, and in a rectangular shape when viewed in a side view in the radial direction RD.
[0040] As shown in Figure 5, the skin plate 16 is joined to close the opening on the ground-side end face of the frame obtained by joining a pair of main girders 11 and a pair of joint plates 12. That is, the skin plate 16 is attached to the outer periphery of the main girders 11 and joint plates 12 that constitute the composite segment 100. When the composite segment 100 is installed in the ground, the skin plate 16 faces the wall of the excavation hole and constitutes the outer periphery wall of the earth retaining structure 200.
[0041] [Anti-slip member 20] As shown in Figure 3, the steel shell 10 includes a shearing retainer 20 that protrudes inward from a pair of main girders 11. The shearing retainer 20 comprises a first portion 21, which is a plate-shaped portion arranged along the circumferential direction CD, and a second portion 22, which is a plate-shaped portion arranged along the radial direction RD. In Embodiment 1, the shearing retainer 20 is an angle steel formed integrally with the plate surfaces of the first portion 21 and the second portion perpendicular to each other. However, the shearing retainer 20 may also be formed by welding together the first portion 21 and the second portion 22, which are each made from separate plate materials. Alternatively, the shearing retainer 20 may be formed by bending a single steel plate into an L-shape.
[0042] The second portion 22 of the shear prevention member 20, along the radial direction RD, holds the wedge-shaped (fan-shaped) concrete 80, as shown by the dashed line in Figure 6, between itself and adjacent second portions 22 in the circumferential direction CD, thereby suppressing displacement between the concrete 80 and the steel shell 10. Furthermore, the first portion 21 extending along the circumferential direction CD of the shear prevention member 20 prevents the concrete 80 from shifting or bulging in the radial direction RD. Moreover, since the first portion 21 and the second portion 22 are integrated, the shear prevention member 20 has high rigidity and a high bonding force with the main girder 11, thus improving the shear prevention effect between the concrete 80 and the steel shell 10.
[0043] The first portion 21 is formed such that its plate surface extends parallel to the tangential direction of the circumferential direction CD and the axial direction AD. As shown in Figure 3, a through hole 25 is formed in the first portion 21. The first portion 21 is provided at the inner diameter end of the second portion 22, which extends along the radial direction RD. The insertion portion 48a of the first load-receiving reinforcement 48 is inserted into the through hole 25, and the end of the first load-receiving reinforcement 48 is positioned inside the through hole 25.
[0044] The shear prevention members 20 are positioned opposite each other in the axial direction AD between a pair of main girders 11 that are arranged with their plate surfaces facing each other. The first reinforcing bars 48 connect the two shear prevention members 20 that are positioned opposite each other when the concrete 80 is filled. The strength of the two opposing shear prevention members 20 against loads in the direction that separates the pair of main girders 11 is improved by the first reinforcing bars 48 inserted into the through holes 25 provided in the first portion 21.
[0045] [Shape-retaining member 23] Figure 8 is a perspective view of the steel shell 10 of the composite segment 100 according to Embodiment 1. Figure 8 shows the state in which no reinforcing bar units 40 are placed inside the steel shell 10. As shown in Figure 8, a shape-retaining member 23 is joined to the inner surface of the skin plate 16. The shape-retaining member 23 protrudes radially RD from the skin plate 16. The shape-retaining member 23 is a plate-shaped member, with its longitudinal direction aligned along the axial direction AD, and both ends in the longitudinal direction are spaced apart from the pair of main girders 11. The shape-retaining member 23 can be easily installed between the pair of main girders 11 because the end faces 23a on both sides of the axial direction AD are spaced apart from the main girders 11. However, the shape-retaining member 23 can also be joined at both ends to either or both of the pair of main girders 11. By installing the shape-retaining member 23 on the skin plate 16, deformation that causes the skin plate 16 to bulge out is suppressed.
[0046] [Reinforcement member 24] The steel shell 10 according to Embodiment 1 includes a reinforcing member 24 that connects the shear-preventing member 20 and the shape-retaining member 23. In Embodiment 1, the reinforcing member 24 is a rectangular plate-shaped member, but is not limited to this shape. One end of the reinforcing member 24 is joined to the second portion 22 of the shear-preventing member 20, and the other end is joined to the shape-retaining member 23.
[0047] The reinforcing member 24 is positioned so as to overlap the plate surface of the second portion 22 of the anti-slip member 20, and the corner formed by the outer surface of the reinforcing member 24 and the plate surface of the second portion 22 at the overlapping portion is welded. For example, the joining area w shown by the dashed line in Figure 7 is welded.
[0048] The reinforcing member 24 is positioned so that its plate surface overlaps with that of the shape-retaining member 23, and the overlapping portion is joined by welding. The reinforcing member 24 may also be positioned so that its radial end face RD abuts against the skin plate 16, and is joined to the skin plate 16 directly or indirectly.
[0049] The shear prevention members 20 are positioned opposite each other in the axial direction AD between a pair of main girders 11, which are arranged with their plate surfaces facing each other. The reinforcing members 24 connect the two opposing shear prevention members 20 via the shape-retaining members 23. The two opposing shear prevention members 20, the shape-retaining members 23, and the two reinforcing members 24 are joined together as a single unit and function like ribs inside the steel shell 10.
[0050] The reinforcing member 24 connects the pair of main girders 11 by connecting the shear-preventing member 20 and the shape-retaining member 23, maintaining the dimensions between the pair of main girders 11 and preventing the main girders 11 from deforming inward or outward. If, for example, a single plate-shaped member is inserted between the pair of main girders 11 to join them, the dimensions between the main girders 11 can be secured, but the plate-shaped member must be formed to match the dimensions between the main girders 11, requiring dimensional adjustment. However, as in the steel shell 10 according to Embodiment 1, by installing the reinforcing member 24 between the shear-preventing member 20 and the shape-retaining member 23, variations in dimensions between the main girders 11 can be absorbed at the joint portion of the reinforcing member 24, and the shear-preventing member 20 and the shape-retaining member 23 are integrally formed, resulting in improved rigidity of the steel shell 10.
[0051] In one main girder 11 of the steel shell 10 according to Embodiment 1, the shear prevention members 20 are arranged at six locations along the circumferential direction CD, four of which are connected to the shape-retaining members 23. The shape-retaining members 23 are arranged at four locations in the circumferential direction. The quantities of the shear prevention members 20 and shape-retaining members 23 are not limited to the illustrated example and can be determined by considering, for example, the size and shape of the composite segment 100.
[0052] [Method for manufacturing synthetic segment 100] Next, a method for manufacturing the synthetic segment 100 will be described.
[0053] Figure 9 is a perspective view of the steel shell 10 of the composite segment 100 according to Embodiment 1. First, the process of assembling the steel shell 10 is carried out. The steel shell 10 is formed by joining a pair of main girders 11 and a pair of joint plates 12 to form a frame, and a skin plate 16 is arranged on the outside of the radial direction RD of the frame. The pair of main girders 11, the pair of joint plates and the skin plate 16 are arranged on a jig, for example, and assembled into the shape of the steel shell 10, and the members are joined together by joining means such as welding.
[0054] After the pair of main girders 11, the pair of joint plates 12, and the skin plate 16 are assembled, a process is carried out to install the internal structure of the steel shell 10. For example, each member constituting the bolt box 82 for connecting the circumferential CD of the composite segment 100 is joined to the main girders 11, the joint plates 12, and the skin plate 16.
[0055] In the process of installing the internal structure of the steel shell 10, a step is taken to join the shear-preventing member 20 to the main girder 11. In addition, a step is taken to join the shape-retaining member 23 to the skin plate 16. The shear-preventing member 20 may be joined to the main girder 11 in advance before assembling the main girder 11 into the shape of the steel shell 10. Similarly, the shape-retaining member 23 may be joined to the skin plate 16 in advance. The shape-retaining member 23 is installed so as to be aligned with the shear-preventing member 20 in the circumferential direction CD. Furthermore, the longitudinal dimension of the shape-retaining member 23 is set to be smaller than the width between the pair of main girders 11, and a gap is left between both longitudinal ends and the main girders 11. After the above steps, the steel shell 10 is formed to the state shown in Figure 9.
[0056] In the steel shell 10 in the state shown in Figure 9, a reinforcing member 24 is joined to connect the shear-preventing member 20 and the shape-retaining member 23. The reinforcing member 24 is joined by a joining means such as welding, with its plate surface in contact with the plate surface of the second portion 22 of the shear-preventing member 20 and the plate surface of the shape-retaining member 23. Once the reinforcing member 24 is joined, the steel shell 10 is formed in the state shown in Figure 8.
[0057] Figure 10 is a perspective view of the steel shell 10 shown in Figure 8 with the reinforcing cage 41 housed inside. After the steel shell 10 is assembled, it is moved to a factory, for example, where concrete 80 is poured. Then, the reinforcing unit 40 is installed inside the steel shell 10. First, the reinforcing cage 41 of the reinforcing unit 40 is placed between the opposing shear prevention members 20 of the steel shell 10. The reinforcing cage 41 is placed on a shape-retaining member 23 installed inside the steel shell 10. As a result, the main reinforcement bars 43 and second distribution reinforcement bars 45 of the reinforcing cage 41 are positioned at a distance from the skin plate 16. This ensures that the main reinforcement bars 43 are positioned with an appropriate cover thickness inside the concrete 80 that is to be filled.
[0058] Figure 11 is a perspective view showing the first reinforcing bar 48 positioned in the steel shell 10 shown in Figure 10. The first reinforcing bar 48 is positioned after the reinforcing cage 41 is positioned correctly. The first reinforcing bar 48 is positioned through the through-holes 25 of the shear prevention members 20, which are positioned opposite each other in a pair of main girders 11, by passing the insertion parts 48a at both ends through them. In Figure 7, the ends of the main body portion 48b of the first reinforcing bar 48 are placed on the upper surface of the first portion 21 of the shear prevention member 20, but the main body portion 48b may be placed on the reinforcing cage 41, and a gap may be set between the main body portion 48b and the first portion 21.
[0059] After the first reinforcing bars 48 are positioned, the main reinforcing bars 42 of the reinforcing cage 41 and the first reinforcing bars 48 are joined. This joining is done by welding or tying with binding wire. The first reinforcing bars 48 and the reinforcing cage 41 can also be joined in advance and installed inside the steel shell 10 as a reinforcing bar unit 40. However, in the case of a structure in which the first reinforcing bars 48 are inserted through holes 25 of the anti-slip member 20, as in the composite segment 100 of Embodiment 1, highly precise alignment is required to pass all of the insertion portions 48a of the multiple first reinforcing bars 48 through the holes 25, which can be difficult depending on the environment of the assembly site. Therefore, by installing the reinforcing cage 41 inside the steel shell 10 first and then installing the first reinforcing bars 48 in a separate process, the reinforcing bar unit 40 can be installed without having to perform difficult alignment work.
[0060] After the reinforcing bar units 40 are placed inside the steel shell 10, concrete 80 is filled in. Formwork is installed on the opening side of the steel shell 10, and concrete 80 is filled into the space formed by the steel shell 10 and the formwork through an injection port 29 located in the center of the steel shell 10. After the concrete 80 hardens, the formwork is removed, and the composite segment 100 is completed.
[0061] [Effects of the synthetic segment 100 according to Embodiment 1] The composite segment 100 according to Embodiment 1 includes a shear prevention member 20 that is joined to each of the pair of main girders 11 and protrudes from one main girder 11 toward the other main girder 11. The shear prevention member 20 includes a first portion 21 whose plate surface is arranged along the circumferential direction CD and a second portion 22 whose plate surface is arranged along the radial direction RD, and the first portion 21 and the second portion 22 are integrally formed. This increases the bonding force between the steel shell 10 and the concrete 80 and also suppresses the shearing of the concrete 80 relative to the steel shell 10.
[0062] The composite segment 100 must function as a single composite structure with a steel shell 10 and concrete 80, and its strength must exceed the theoretical value, and its deformation must behave in a manner similar to the theoretical value. Furthermore, the composite segment 100 must be structured to withstand the force (internal pressure) that causes the concrete 80 to protrude from the steel shell 10 when a tensile load is applied to it. In addition, the composite segment 100 must maintain a constant position of its neutral axis even when subjected to bending loads and large strains. Ideally, the distribution of generated stress should be the same or similar in any cross-section perpendicular to the circumferential direction CD of the composite segment 100.
[0063] According to the composite segment 100 of Embodiment 1, the presence of the shear-preventing member 20 increases the bonding strength between the concrete 80 and the steel shell 10, thus establishing a composite structure.
[0064] Furthermore, the shear prevention members 20 are provided in pairs on each of the pair of main girders 11, at positions facing each other in the axial direction. The first distribution reinforcement bars 48, which extend in the axial direction, have both ends inserted through holes 25 provided in the shear prevention members 20. As a result, when the concrete 80 is filled, the pair of opposing main girders 11 are connected by the first distribution reinforcement bars 48, and the composite segment 100 has improved strength against loads pulled in the axial direction AD.
[0065] Furthermore, by further comprising a shape-retaining member 23 whose longitudinal direction is aligned with the axial direction, joined to the skin plate 16 and protruding radially RD, and a reinforcing member 24 joined to the shear-preventing member 20 and the shape-retaining member 23, the rigidity and strength of the steel shell 10 are improved in a direction that makes it difficult for the distance between the pair of main girders 11 to fluctuate. In addition, because the shear-preventing member 20, the shape-retaining member 23, and the reinforcing member 24 create a structure in which ribs are erected on the inside of the steel shell 10, the bonding force between the concrete 80 and the steel shell 10 is high. Moreover, because the height of the shape-retaining member 23 from the skin plate 16 is kept low, space is secured to place the reinforcing cage 41 inside the steel shell 10, and the composite segment 100 is easy to manufacture while ensuring a composite structure.
[0066] Furthermore, the manufacturing method for the composite segment 100 according to Embodiment 1 includes the steps of assembling the steel shell 10 and joining the shear-preventing members 20 to a pair of main girders, after which the reinforcing cage 41 can be placed between the opposing shear-preventing members 20. Therefore, there is a high degree of freedom in the arrangement of the reinforcing bars, the strength of the composite segment 100 can be increased, and manufacturing is easy.
[0067] Furthermore, the manufacturing method for the composite segment 100 includes a step of joining the first reinforcing bar 48 to the main reinforcing bars 42 of the reinforcing cage 41. By inserting the insertion portion 48a of the first reinforcing bar 48 through the through hole 25 of the shear prevention member 20 and then joining it to the reinforcing cage 41, the effort of positioning the reinforcing bar unit 40 and the steel shell 10 is eliminated.
[0068] Furthermore, the manufacturing method for the composite segment 100 includes a step of joining the shape-retaining member 23 to the skin plate 16 such that its longitudinal direction is aligned with the axial direction AD and protrudes from the skin plate 16 inside the steel shell 10, with both longitudinal end faces of the shape-retaining member 23 spaced apart from the pair of main girders 11. In addition, the manufacturing method for the composite segment 100 includes a step of joining a reinforcing member 24 to the shape-retaining member 23 and the second portion 22 of the shear prevention member 20. This allows the shape-retaining member 23 to be installed inside the steel shell 10 without dimensional adjustment.
[0069] [Example of composite segment 100] Figure 12 is a schematic cross-sectional view showing the internal structure of a modified example of the composite segment 100 according to Embodiment 1. The reinforcing bar unit 40 used in the composite segment 100 can be modified as appropriate. As an example, the reinforcing bar unit 40A shown in Figure 12 has a shape in which the first distribution reinforcing bar 48A extends in a straight line, with its end protruding from the reinforcing bar cage 41 in the axial direction AD and resting on the first portion 21 of the shear prevention member 20. In this case, the first distribution reinforcing bar 48A may be joined to the reinforcing bar cage 41 in advance.
[0070] The reinforcing bar unit 40A shown in Figure 12 does not have a structure in which the first distribution reinforcing bar 48 is inserted into the through hole 25, and therefore can be positioned without requiring highly precise positioning relative to the steel shell 10. Furthermore, the reinforcing bar unit 40A can have its bonding strength with the steel shell 10 increased by joining the first distribution reinforcing bar 48 to the shear prevention member 20 by means of welding or other means.
[0071] Figure 13 is a schematic cross-sectional view showing the internal structure of a modified example of the composite segment 100 according to Embodiment 1. The reinforcing bar unit 40 of the composite segment 100 can also omit the first distribution reinforcement 48. Even in this case, since the reinforcing bar unit 40B is placed on the shape-retaining member 23 installed on the steel shell 10, the reinforcement can be positioned in the appropriate location inside the composite segment 100.
[0072] Figures 14, 15, and 16 are a top view and a side view of a modified example of the anti-slip member 20 of the composite segment 100 according to Embodiment 1. The anti-slip member 20A shown in Figure 14 is formed in a T-shape in the side view shown in (b). That is, a second portion 22 extending radially RD from the central part of a first portion 21, in which a plate surface is arranged along the circumferential direction CD, is joined. The anti-slip member 20A may be formed by joining the first portion 21 and the second portion 22 by means of welding or other means, or a pre-formed integral part may be used.
[0073] The anti-slip member 20B shown in Figure 15 is formed in a cross shape in the side view shown in (b). The anti-slip member 20B is formed by welding together two plate materials having notches 21a, for example, as shown in Figure 15(c), by joining the notches 21a together. The anti-slip member 20B may also be pre-formed as a single unit.
[0074] The anti-slip member 20B allows the first reinforcing bar 48A shown in Figure 12 to be placed at the corner 20c. This also enables the positioning of the reinforcing bar unit 40.
[0075] The shear prevention member 20C shown in Figure 16 has a second portion 22 that protrudes radially RD from the first portion 21, and in the side view shown in (b), it has a shape that is a T-shape rotated by 90°. The shear prevention member 20C can also have the first load-receiving reinforcement 48A placed at the corner portion 20c.
[0076] The anti-slip members 20A, 20B, and 20C shown in Figures 14, 15, and 16 may also be provided with through holes 25, similar to the anti-slip member 20.
[0077] Although embodiments have been described above, this disclosure is not limited to the configurations of the embodiments described above. In particular, the combination of components is not limited to the combinations in the embodiments and can be changed as appropriate. For example, the anti-slip member 20 can be used in combination with modified anti-slip members 20A, 20B, and 20C, etc. It should also be noted that the scope of the technical disclosure includes various modifications, applications, and uses that a person skilled in the art may make as needed.
[0078] The composite segment 100 described above may also include combinations of the features shown in the following appendices 1 to 20. These combinations are shown below. [Note 1] A composite segment that constitutes a cylindrical body buried underground as a retaining wall structure, A pair of main beams extending in the circumferential direction of the cylindrical body and arranged with their plate surfaces facing each other in the axial direction of the cylindrical body, A pair of joint plates joined to both ends in the circumferential direction of each of the pair of main girders, A skin plate is joined to the outer circumference of the cylindrical body to the frame composed of the pair of main girders and the pair of joint plates, Each of the pair of main girders is joined to a shearing member that protrudes from one main girder toward the other main girder, The aforementioned anti-slip member is The plate surface comprises a first portion arranged along the circumferential direction, The plate surface comprises a second portion arranged along the radial direction of the cylindrical body, A composite segment in which the first part and the second part are formed integrally. [Note 2] The aforementioned anti-slip member is The composite segments described in Appendix 1 are provided on each of the pair of main girders in pairs at positions facing each other in the axial direction. [Note 3] The unit comprises a reinforcing bar unit positioned between the pair of main girders, The aforementioned reinforcing unit is The system includes a first force distribution muscle extending in the axial direction, Both ends of the first muscle that distributes force are The composite segment described in Appendix 2 is placed on the plate surface of the first portion of the anti-slip member. [Note 4] The aforementioned anti-slip member is A through hole is formed in the first portion. The first muscle that distributes force is, The main body portion extending in the axial direction, The main body comprises insertion portions extending radially from both ends of the main body, The aforementioned insertion part is, The composite segment described in Appendix 3 is inserted into the aforementioned through hole. [Note 5] The aforementioned reinforcing unit is The main reinforcement extending in the circumferential direction, The system comprises a second distribution reinforcement extending in a direction intersecting the main reinforcement, The main reinforcement and the second distribution reinforcement are joined to a composite segment as described in Appendix 3 or 4. [Note 6] The first muscle that distributes force is, The composite segment described in Appendix 5, which is joined to the main reinforcement. [Note 7] The aforementioned anti-slip member is A composite segment as described in any one of the appendices 1 to 6, which is formed in an L-shape when viewed from the axial direction. [Note 8] The aforementioned anti-slip member is A composite segment as described in any one of the appendices 1 to 6, which is formed in a T-shape when viewed from the axial direction. [Note 9] The aforementioned anti-slip member is A composite segment as described in any one of the appendices 1 to 6, which is formed in a cross shape when viewed from the axial direction. [Note 10] A composite segment according to any one of appendices 1 to 9, further comprising a shape-retaining member whose longitudinal direction is arranged along the axial direction, joined to the skin plate, and protruding in the radial direction. [Note 11] The shape-retaining member is The composite segment according to Appendix 10, wherein both axial end faces are spaced apart from the pair of main girders. [Note 12] The composite segment according to appendix 10 or 11, further comprising a reinforcing member joined to the anti-slip member and the shape-retaining member. [Note 13] A retaining structure formed by combining multiple composite segments described in any one of the appendices 1 to 12 in the circumferential and axial directions. [Note 14] A method for manufacturing a synthetic segment that constitutes a cylindrical body buried underground as a retaining wall structure, A step of assembling a steel shell by joining a pair of main girders extending in the circumferential direction of the cylindrical body and arranged with their plate surfaces facing each other in the axial direction of the cylindrical body, a pair of joint plates joined to both ends of the pair of main girders in the circumferential direction, and a skin plate joined to the outer circumference of the cylindrical body to a frame composed of the pair of main girders and the pair of joint plates, The process includes joining a shearing prevention member to each of the pair of main girders so as to protrude from one main girder toward the other main girder, The step of joining the aforementioned anti-slip member is: A method for manufacturing a composite segment, comprising joining the anti-slip member to each of the pair of main girders such that the plate surface of the first portion of the anti-slip member is arranged along the circumferential direction and the plate surface of the second portion is arranged along the radial direction of the cylindrical body. [Note 15] The process of placing a reinforcing cage inside the steel shell, A method for manufacturing a synthetic segment according to Appendix 14, comprising the step of placing a first force distribution reinforcement on the first portion of the shear-preventing member. [Note 16] The step of placing the first force distribution reinforcement on the first portion of the shear prevention member is: A method for manufacturing a composite segment according to Appendix 15, wherein an insertion portion formed at the end of the first force distribution reinforcement is inserted into a through hole formed in the first portion of the anti-slip member. [Note 17] A method for manufacturing a composite segment according to Appendix 15 or 16, further comprising the step of joining the first distribution reinforcement to the main reinforcement of the reinforcing cage. [Note 18] The process further comprises a step of joining a shape-retaining member to the skin plate such that its longitudinal direction is aligned with the axial direction and it protrudes from the skin plate inside the steel shell, The step of joining the shape-retaining member to the skin plate is: A method for manufacturing a composite segment according to any one of the appendices 14 to 17, wherein the longitudinal end faces of the shape-retaining member are spaced apart from the pair of main girders. [Note 19] The method for manufacturing a composite segment according to Appendix 18, further comprising the step of joining a reinforcing member to the shape-retaining member and the second portion of the slip-preventing member. [Note 20] A method for manufacturing a synthetic segment according to any one of appendices 14 to 19, comprising the steps of covering the steel shell with a formwork and filling the inside of the steel shell with a filler. [Explanation of Symbols]
[0079] 10 Steel shell, 11 Main girder, 12 Joint plate, 13 Bolt hole, 14 Boss, 15 Bolt hole, 16 Skin plate, 20 Anti-slip member, 20A Anti-slip member, 20B Anti-slip member, 20C Anti-slip member, 20c Corner, 21 First section, 21a Notch, 22 Second section, 23 Shape-retaining member, 23a End face, 24 Reinforcement member, 25 Through hole, 26 Shape-retaining member, 29 Inlet, 40 Reinforcement unit, 40A Reinforcement unit, 40B Reinforcement unit, 41 Reinforcement cage, 42 Main reinforcement, 43 Main reinforcement, 45 (Second) distribution reinforcement, 45a Main body, 45b Arm section, 45c Tip section, 48 (First) distribution reinforcement, 48A First distribution reinforcement, 48a Insertion section, 48b Main body, 80 concrete, 81 bolt box, 82 bolt box, 90 ground, 91 section, 92 connecting section, 93 connecting section, 100 composite segment, 150 segment ring, 200 earth retaining structure, AD axial direction, CD circumferential direction, RD radial direction, w connection range.
Claims
1. A composite segment that constitutes a cylindrical body buried underground as a retaining wall structure, A pair of main beams extending in the circumferential direction of the cylindrical body and arranged with their plate surfaces facing each other in the axial direction of the cylindrical body, A pair of joint plates joined to both ends in the circumferential direction of each of the pair of main girders, A skin plate is joined to the outer circumference of the cylindrical body to the frame composed of the pair of main girders and the pair of joint plates, A shear prevention member is joined to each of the pair of main girders and protrudes from one main girder toward the other main girder, A shape-retaining member whose longitudinal direction is aligned with the axial direction, joined to the skin plate and protruding radially from the cylindrical body, The system comprises a reinforcing member joined to the aforementioned anti-slip member and the aforementioned shape-retaining member, The aforementioned anti-slip member is The first portion of the plate surface is arranged along the circumferential direction, The plate surface comprises a second portion arranged along the radial direction, A composite segment in which the first part and the second part are formed integrally.
2. The shape-retaining member is The composite segment according to claim 1, wherein both axial end faces are spaced apart from the pair of main girders.
3. The aforementioned anti-slip member is The composite segment according to claim 2, wherein each of the pair of main girders is provided in pairs at positions opposite to each other in the axial direction.
4. The aforementioned anti-slip member is A composite segment according to any one of claims 1 to 3, which is formed in an L-shape when viewed from the axial direction.
5. The aforementioned anti-slip member is A composite segment according to any one of claims 1 to 3, which is formed in a T-shape when viewed from the axial direction.
6. The aforementioned anti-slip member is A composite segment according to any one of claims 1 to 3, which is formed in a cross shape when viewed from the axial direction.
7. A retaining structure formed by combining a plurality of composite segments according to any one of claims 1 to 3 in the circumferential and axial directions.