Composite segments and earth retaining structures

Abstract

To provide a synthetic segment capable of obtaining a high fixing effect of concrete while reducing the cost, and an earth retaining structure.SOLUTION: The synthetic segment is a synthetic segment for constructing an earth-retaining structure by connecting multiple segments in the circumferential direction and axial direction of the earth-retaining structure, each including a steel shell and concrete filled inside the steel shell. The steel shell includes: a pair of main girders spaced apart in the axial direction; a skin plate joined to the outer circumference of the main girder; a pair of joint plates joined to both ends of the main girder in the circumferential direction; and a first anti-slip bar extending in the circumferential direction. The first anti-slip bar is joined to the inner surface of the main girder.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a composite segment that forms an earth retaining structure sunk into the ground, and to the earth retaining structure. [Background technology]

[0002] The Urban Ring Method (registered trademark) is a conventionally known method for press-in construction of earth-retaining structures to build vertical underground structures. In the Urban Ring Method, earth-retaining panels are assembled into a ring-shaped structure at the installation site, and the ring-shaped structure is pressed into the ground using a press-in device. After the ring-shaped structure is pressed into the ground, the inside of the ring-shaped structure is excavated and soil is removed, and a new ring-shaped structure is added on top of it. This work process is repeated up to a predetermined depth to construct an underground structure such as a shaft.

[0003] Another tunnel construction method is the shield tunneling method, in which a tunneling machine installed inside a vertical shaft excavates a certain distance, and then at the rear of the tunnel, a segment ring is constructed by assembling, for example, arc-shaped composite segments into a ring, and these are then successively extended to form a cylindrical lining, thereby constructing a shield tunnel.

[0004] The composite segments used in the above-mentioned shafts or tunnels are formed by filling a filler material such as concrete inside a steel shell having main girders that form the axial end faces of the earth-retaining structure, joint plates that form the circumferential end faces, and skin plates that form the outer peripheral surface, and then hardening the filler material (see, for example, Patent Document 1). Such composite segments are able to withstand earth pressure from the surrounding ground by ensuring strength and rigidity by forming the steel shell and concrete integrally.

[0005] In the composite segment described in Patent Document 1, when the circumferential load of the earth-retaining structure is applied, the concrete displaces so that it bulges out radially inward of the earth-retaining structure, and to prevent the concrete from peeling off from the steel shell, mesh steel bars, which are concrete fixing members that fix the concrete to the steel shell, are provided on the inner surface of the skin plate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-144504 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the composite segment described in Patent Document 1, mesh reinforcing bars, which serve as concrete anchoring members, are provided on the inner surface of the skin plate, which has low rigidity in the radial direction of the earth-retaining structure, which is the direction in which the concrete peels off, and this means that the concrete is not sufficiently anchored to the steel shell, which could result in the concrete peeling off from the steel shell.In addition, the mesh reinforcing bars, which serve as concrete anchoring members, are composed of multiple vertical reinforcing bars arranged at specified intervals and horizontal reinforcing bars arranged at specified intervals on top of the vertical reinforcing bars and perpendicular to them, with the intersections of the two bars welded together, which poses the problem of high costs due to the large number of reinforcing bars.

[0008] The present invention has been made to solve the above-mentioned problems, and aims to provide a composite segment and retaining structure that can achieve a high anchoring effect for concrete and reduce costs. [Means for solving the problem]

[0009] The composite segment according to the present invention is a composite segment that constructs an earth-retaining structure by being connected in multiple ways in the circumferential and axial directions of the earth-retaining structure, and comprises a steel shell and concrete filled inside the steel shell, wherein the steel shell has a pair of main girders spaced apart in the axial direction, a skin plate joined to the outer periphery of the main girders, a pair of joint plates joined to both ends of the main girders in the circumferential direction, and a first shear stop bar extending in the circumferential direction, and the first shear stop bar is joined to the inner surface of the main girders The steel shell is joined between the pair of main girders and has a plurality of shape-retaining members extending in the axial direction, and the concrete is provided with a plurality of main reinforcements extending in the circumferential direction and spaced apart in the axial direction, a plurality of distribution reinforcements extending in the axial direction and spaced apart in the circumferential direction, inner reinforcement arranged on the inner periphery of the earth-retaining structure and consisting of the plurality of main reinforcements or the plurality of main reinforcements and the plurality of distribution reinforcements, outer reinforcement arranged on the outer periphery of the earth-retaining structure and consisting of the plurality of main reinforcements and the plurality of distribution reinforcements, and connecting reinforcement that is separate from the plurality of distribution reinforcements and connects the inner reinforcement and the outer reinforcement. It is something.

[0010] The earth retaining structure according to the present invention is formed by combining a plurality of the above-described composite segments in the circumferential direction and the axial direction. [Effects of the Invention]

[0011] In the composite segment according to the present invention, the first shear stop rebars extending circumferentially of the earth-retaining structure are spaced apart radially of the structure and joined to the inner surface of the main girder. In other words, the first shear stop rebars, which serve as concrete anchoring members, are located on the inner surface of the main girder, where resistance to peeling is higher than that of the skin plate, resulting in a high level of concrete anchoring. Furthermore, because the concrete anchoring members are made up solely of the first shear stop rebars extending circumferentially of the earth-retaining structure, the number of rebars can be reduced, leading to cost savings. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a conceptual diagram of an earth retaining structure according to an embodiment. [Figure 2] FIG. 2 is a conceptual diagram of a segment ring according to an embodiment, viewed in the axial direction. [Figure 3] FIG. 2 is a perspective view schematically illustrating a composite segment according to an embodiment. [Figure 4] FIG. 2 is a perspective view of a steel shell of a composite segment according to an embodiment, as viewed from the inner periphery side. [Figure 5] FIG. 2 is a perspective view of a steel shell of a composite segment according to an embodiment, as viewed from the outer periphery side. [Figure 6] FIG. 2 is a schematic vertical cross-sectional view of a steel shell of a composite segment according to an embodiment, as viewed from the side. [Figure 7] FIG. 4 is a schematic vertical cross-sectional view of a steel shell according to a first modified example of the composite segment according to the embodiment, as viewed from the side. [Figure 8] FIG. 10 is a schematic vertical cross-sectional view of a steel shell according to a second modified example of the composite segment of the embodiment, as viewed from the side. [Figure 9] FIG. 10 is a schematic vertical cross-sectional view of a steel shell according to a third modified example of the composite segment of the embodiment, as viewed from the side. [Figure 10] FIG. 10 is a schematic vertical cross-sectional view of a steel shell according to a fourth modified example of the composite segment of the embodiment, as viewed from the side. DETAILED DESCRIPTION OF THE INVENTION

[0013] The composite segment according to the embodiment will be described below with reference to the drawings. Note that in the following drawings, including FIG. 1, the relative dimensional relationships and shapes of the components may differ from the actual ones. In the following drawings, the same reference numerals denote the same or equivalent components, and this applies throughout the entire specification. To facilitate understanding, terms indicating directions (e.g., up, down, left, right, front, rear, front and back, etc.) are used as appropriate, but these notations are for the convenience of explanation and do not limit the arrangement, direction or orientation of devices, instruments, parts, etc.

[0014] Embodiment [Earth retaining structure 200] Fig. 1 is a conceptual diagram of an earth-retaining structure 200 according to an embodiment. Note that, in Fig. 1, an axial direction AD represents the axial direction of the earth-retaining structure 200, and a circumferential direction CD represents the circumferential direction of the earth-retaining structure 200. Furthermore, a radial direction RD represents the radial direction of the earth-retaining structure 200, with the Y1 side representing the inner circumferential side of the earth-retaining structure 200 and the Y2 side representing the outer circumferential side of the earth-retaining structure 200.

[0015] The earth-retaining structure 200 is a structure used, for example, as an earth-retaining wall in the press-in caisson method, and is a structure that covers an excavated surface underground in construction methods such as the press-in method. The earth-retaining structure 200 is sunk into the ground. The earth-retaining structure 200 is formed in a cylindrical shape and has a hollow portion. The earth-retaining structure 200 has a plurality of segment rings 150, which are formed by connecting the plurality of segment rings 150 in succession in the direction in which the tunnel extends.

[0016] [Segment Ring 150] 2 is a conceptual diagram of a segment ring 150 according to an embodiment, viewed in the axial direction AD. The segment ring 150 is a structure that covers an excavation surface underground. The segment ring 150 is formed in an annular shape when viewed in the axial direction AD, and is formed in a cylindrical shape overall. The segment ring 150 is formed, for example, in a cylindrical shape, but is not limited to a cylindrical shape and may be an elliptical or rectangular shape when viewed in the axial direction.

[0017] The earth-retaining structure 200 is constructed by connecting a plurality of segment rings 150 in the direction in which the earth-retaining structure 200 extends, i.e., along the axial direction AD. When the earth-retaining structure 200 is used in a shield tunneling method, for example, the earth-retaining structure 200 is constructed by arranging the segment rings 150 one around the cross section of the tunnel (one ring). Therefore, the segment ring 150 constitutes one unit of the earth-retaining structure 200 in the direction in which the tunnel extends.

[0018] The segment ring 150 is divided into a plurality of combined segments 100 in the circumferential direction CD. That is, a plurality of combined segments 100 are arranged in a ring shape, and adjacent combined segments 100 are connected to each other to form the segment ring 150. Note that, although the segment ring 150 shown in FIG. 2 is illustrated as if the combined segments 100 are approximately equal in size in the circumferential direction CD, the combined segments 100 may be formed to have different sizes depending on their installation positions in the circumferential direction CD.

[0019] 1, in the earth-retaining structure 200, adjacent segment rings 150 in the axial direction AD are assembled in a state in which the composite segments 100 constituting the segment ring 150 are displaced in the circumferential direction CD. More specifically, in the earth-retaining structure 200, the composite segments 100 constituting the segment ring 150 are constructed in a staggered arrangement.

[0020] [Synthetic Segment 100] Fig. 3 is a perspective view schematically showing a composite segment 100 according to an embodiment. Fig. 4 is a perspective view of the steel shell 10 of the composite segment 100 according to an embodiment, as viewed from the inner peripheral side. Fig. 5 is a perspective view of the steel shell 10 of the composite segment 100 according to an embodiment, as viewed from the outer peripheral side. Fig. 6 is a schematic vertical cross-sectional view of the steel shell 10 of the composite segment 100 according to an embodiment, as viewed from the side.

[0021] The composite segments 100 are arranged in a ring shape and connected to each other in the circumferential direction CD to form a cylindrical segment ring 150 that covers the excavation surface underground. The segment rings 150 are also connected along the axial direction AD to construct the earth-retaining structure 200. In other words, the earth-retaining structure 200 is constructed by connecting multiple composite segments 100 in the circumferential direction CD and the axial direction AD.

[0022] The composite segment 100 is a box-shaped structure made by combining multiple steel materials. The composite segment 100 is formed in an arc shape when viewed in the axial direction AD of the segment ring 150, and is formed in a curved shape as a whole.

[0023] In addition, the composite segment 100 has an arc-shaped steel shell 10 surrounded by five sides and open on the Y1 side in the radial direction RD, and concrete 80 as a filler filled inside it, and the steel shell 10 and the concrete 80 are integrated.

[0024] As shown in Figures 3 to 6, the steel shell 10 comprises a pair of main girders 11 made of steel plates formed in an arc shape along the circumferential direction CD, a skin plate 16 made of steel plate welded to the outer periphery of the pair of main girders 11, a pair of joint plates 12 made of steel plates formed in a rectangular shape and welded to both ends of the pair of main girders 11 and the skin plate 16, and a plurality of shape-retaining members 20 arranged at intervals in the circumferential direction CD between the pair of joint plates 12 and extending in the axial direction AD, and is open on the Y1 side (inner peripheral side) in the radial direction RD.

[0025] The skin plate 16 is formed in an arc shape when viewed in the axial direction AD and in a rectangular shape when viewed in the radial direction RD. The skin plate 16 forms the peripheral wall of the composite segment 100 when the steel shell 10 is installed underground.

[0026] The main girders 11 are provided at both ends of the skin plate 16 in the axial direction AD, i.e., at the upper and lower ends, and form the upper and lower surfaces of the steel shell 10. When the steel shell 10 is installed underground, the main girders 11 provided at the upper ends of the skin plates 16 form the ceiling wall of the composite segment 100, and the main girders 11 provided at the lower ends of the skin plates 16 form the bottom wall of the composite segment 100.

[0027] The joint plates 12 are provided at both ends of the skin plate 16 in the circumferential direction CD, i.e., at the left and right ends, and form the left and right sides of the steel shell 10. When the steel shell 10 is installed underground, the joint plates 12 provided at both ends of the skin plate 16 in the circumferential direction CD form the side walls of the composite segment 100.

[0028] The steel shell 10 is provided with a shape-retaining member 20 disposed between a pair of main girders 11 and extending in the axial direction AD. The shape-retaining member 20 is disposed so as to form a gap 60 between itself and the skin plate 16. A plurality of shape-retaining members 20 are disposed at intervals in the circumferential direction CD and are arranged perpendicular to the pair of main girders 11. The shape-retaining member 20 is formed of, for example, a plate-like member made of a steel plate and is formed into a rectangular shape as viewed in the circumferential direction CD. However, the shape-retaining member 20 is not limited to a steel plate. The lateral dimension of the shape-retaining member 20 is shorter than the lateral dimension of the joint plate 12. The shape-retaining member 20 is disposed to ensure the dimension between the main girders 11 during the fabrication of the composite segment 100.

[0029] In the illustrated example, the shape-retaining members 20 are arranged in pairs with a small gap between them in the circumferential direction CD, and three pairs of shape-retaining members 20 are arranged with a large gap between them in the circumferential direction CD. In other words, six shape-retaining members 20 are arranged with varying gaps between them in the circumferential direction CD. The shape-retaining members 20 do not have to be arranged in pairs with a small gap between them in the circumferential direction CD, and the shape and number of the shape-retaining members 20 are not limited to those in the illustrated example and may be determined taking into consideration, for example, the size and shape of the steel shell 10.

[0030] The main girders 11 are formed with a plurality of connecting holes 13 for connecting vertically adjacent steel shells 10 arranged in the axial direction AD. Vertically adjacent steel shells 10 are connected by butting the main girders 11 together and fastening the shanks of bolts inserted into the connecting holes 13 with nuts. Note that one-touch joints may be used instead of bolts and nuts as components for connecting vertically adjacent steel shells 10.

[0031] The joint plates 12 are formed with a plurality of connecting holes 14 for connecting adjacent steel shells 10 on the left and right in the circumferential direction CD. The adjacent steel shells 10 on the left and right are connected by butting the joint plates 12 together and fastening the shanks of bolts inserted into the connecting holes 14 with nuts.

[0032] The numbers of connecting holes 13, 14 shown in the drawings are merely examples and are not limited to the examples shown in the drawings. The numbers are determined taking into consideration the size and shape of the steel shell 10, for example.

[0033] A plurality of bolt boxes 81 are formed below the concrete 80 at intervals in the circumferential direction CD. These bolt boxes 81 are formed at positions corresponding to the connecting holes 13. After the steel shell 10 is filled with concrete 80, bolts can be inserted from the bolt boxes 81 into the connecting holes 13 and fastened with nuts. Furthermore, at both ends of the concrete 80 in the circumferential direction CD, a plurality of bolt boxes 82 are formed at intervals in the axial direction AD. These bolt boxes 82 are formed at positions corresponding to the connecting holes 14. After the steel shell 10 is filled with concrete 80, bolts can be inserted from the bolt boxes 82 into the connecting holes 14 and fastened with nuts.

[0034] First shear stop rebars 51 extending in the circumferential direction CD are provided on the inner surface of each main girder 11. Multiple first shear stop rebars 51 are provided at intervals in the radial direction RD, and abut against the inner surface of the main girder 11, welded and joined at the abutting points. Note that the number of first shear stop rebars 51 may be one rather than multiple. In the illustrated example, two first shear stop rebars 51 are provided at intervals in the radial direction RD. Furthermore, second shear stop rebars 52 extending in the circumferential direction CD are provided on the inner surface of the skin plate 16. Multiple second shear stop rebars 52 are provided at intervals in the axial direction AD, and abut against the inner surface of the skin plate 16, welded and joined at the abutting points. In the illustrated example, two second shear stop rebars 52 are provided at intervals in the axial direction AD. The first and second shear stop bars 51 and 52 are concrete anchoring members that anchor the concrete 80 to the steel shell 10 and prevent the concrete 80 from peeling off from the steel shell 10. In other words, the first and second shear stop bars 51 and 52 strengthen the integration between the steel shell 10 and the concrete 80.

[0035] The first shear stop bars 51 do not have to be welded to the main girders 11 at all of their contact points, but only need to be welded to some of their contact points with the main girders 11. Similarly, the second shear stop bars 52 do not have to be welded to the skin plates 16 at all of their contact points, but only need to be welded to some of their contact points with the skin plates 16. The shapes and the number of the first shear stop bars 51 and the second shear stop bars 52 are not limited to those shown in the drawings, and are determined taking into consideration the size and shape of the steel shell 10, for example.

[0036] In this way, by providing the first shear stop rebars 51 on the inner surface of the main girder 11, which has a higher resistance to peeling than the skin plate 16, the shifting of the concrete 80 toward the Y1 side (inner periphery) in the radial direction RD is suppressed, and a high anchoring effect for the concrete 80 is achieved. Furthermore, because the concrete anchoring member is composed only of the first shear stop rebars 51 extending in the circumferential direction CD, the number of rebars can be reduced, resulting in cost savings. Furthermore, by providing the second shear stop rebars 52 on the inner surface of the skin plate 16, a higher anchoring effect for the concrete 80 is achieved. Furthermore, by providing the first shear stop rebars 51 and the second shear stop rebars 52, the strength of the composite segment 100 against loads applied in the circumferential direction CD can be improved.

[0037] Furthermore, the concrete 80 is provided with inner reinforcing bars 40 arranged on the Y1 side (inner circumferential side) in the radial direction RD, and outer reinforcing bars 41 arranged on the Y2 side (outer circumferential side). Specifically, the outer reinforcing bars 41 are arranged in gaps 60 formed between the shape-retaining member 20 and the skin plate 16, and the inner reinforcing bars 40 are arranged on the inner circumferential side of the shape-retaining member 20. In this way, the inner reinforcing bars 40 and the outer reinforcing bars 41 are arranged in the space within the steel shell 10 secured by abutting the first shear stop bars 51 and the second shear stop bars 52 against the inner surfaces of the main girder 11 and the skin plate 16.

[0038] The inner reinforcing bars 40 are composed of multiple main reinforcements 42 arranged at intervals in the axial direction AD and extending in the circumferential direction CD, and multiple distribution reinforcements 44 arranged at intervals in the circumferential direction CD and extending in the axial direction AD. The main reinforcements 42 abut the distribution reinforcements 44 on the side opposite the skin plate 16, and the abutting points are joined to form an integrated structure. The distribution reinforcements 44 have L-shaped curved ends, sandwiching the multiple main reinforcements 42. The ends of the distribution reinforcements 44 are welded to the shape-retaining member 20. Joining the distribution reinforcements 44 to the shape-retaining member 20 in this manner improves resistance to abdominal pressure. Here, abdominal pressure refers to a secondary normal force acting toward the center of the cylindrical earth-retaining structure 200 when tensile force is generated in the main reinforcements 42 arranged in the earth-retaining structure 200 in a section where the cylindrical earth-retaining structure 200 is subjected to tension.

[0039] The outer reinforcing bars 41 are composed of a plurality of main reinforcements 43 arranged at intervals in the axial direction AD and extending in the circumferential direction CD, and a plurality of distribution reinforcements 45 arranged at intervals in the circumferential direction CD and extending in the axial direction AD. The main reinforcements 43 abut the side of the distribution reinforcements 45 opposite the skin plate 16, and the abutting points are joined together, integrating them. The distribution reinforcements 45 have linear tips that are welded to the shape-retaining member 20. Joining the distribution reinforcements 45 and the shape-retaining member 20 in this way improves resistance to abdominal pressure.

[0040] The main reinforcements 42, 43 do not have to be welded to the distribution reinforcements 44, 45 at all of their contact points, but may be welded to some of their contact points. Although the distribution reinforcement 44 has been described above as having an L-shaped curved tip, this is not limited to the illustrated example, and the tip may be straight. Although the distribution reinforcement 45 has been described as having a straight tip, this is not limited to the illustrated example, and the tip may be L-shaped. Although the main reinforcements 42, 43 have been described as contacting the side of the distribution reinforcement 44, 45 opposite the skin plate 16, this is not limited to the illustrated example, and the main reinforcement 42, 43 may be contacting the side of the distribution reinforcement 44, 45 facing the skin plate 16.

[0041] In the illustrated example, four main reinforcements 42, 43 are arranged at intervals in the axial direction AD. In addition, in the illustrated example, two distribution reinforcements 44 are arranged at offset positions in the axial direction AD, and these two are arranged in pairs with a small gap in the circumferential direction CD, and three pairs of distribution reinforcements 44 are arranged with a large gap in the circumferential direction CD. In addition, in the illustrated example, distribution reinforcements 45 are arranged in pairs with a small gap in the circumferential direction CD, and three pairs of distribution reinforcements 45 are arranged with a large gap in the circumferential direction CD. In other words, twelve distribution reinforcements 44 are arranged with varying gaps in the circumferential direction CD, and six distribution reinforcements 45 are arranged with varying gaps in the circumferential direction CD.

[0042] The inner reinforcing bars 40 and the outer reinforcing bars 41 are embedded and fixed in the concrete 80, thereby improving the strength of the concrete 80. The shapes and the number of the inner reinforcing bars 40 and the outer reinforcing bars 41 are not limited to the illustrated example, and are determined taking into consideration the size and shape of the composite segment 100, for example.

[0043] FIG. 7 is a schematic vertical cross-sectional view of a steel shell 10 according to a first modified example of the composite segment 100 of the embodiment, as viewed from the side.

[0044] In the first modified example of the embodiment, connecting rebars 46 are provided in the concrete 80 to connect the inner rebars 40 and the outer rebars 41. In the illustrated example, two connecting rebars 46 are provided at intervals in the axial direction AD, and six connecting rebars 46 are provided at intervals in the circumferential direction CD. The connecting rebars 46 surround the main rebars 42 on both sides of the inner rebar 40 in the axial direction AD and the main rebars 43 on both sides of the outer rebar 41 in the axial direction AD. In other words, the connecting rebars 46 straddle the main rebars 42, 43 in the radial direction RD, connecting the inner rebar 40 and the outer rebar 41 and maintaining their positions. In this way, the provision of connecting rebars 46 connecting the inner rebars 40 and the outer rebars 41 further improves the strength of the concrete 80. Note that the shape and number of connecting rebars 46 are not limited to those in the illustrated example, and any shape and number may be used as long as they can maintain the positions of the inner rebars 40 and the outer rebars 41. Furthermore, the connecting reinforcing bars 46 are described as connecting the inner reinforcing bars 40 and the outer reinforcing bars 41 and maintaining their positions by surrounding the main reinforcing bars 42 on both sides of the axial direction AD of the inner reinforcing bars 40 and the main reinforcing bars 43 on both sides of the axial direction AD of the outer reinforcing bars 41, but are not limited to the illustrated example. For example, any other structure may be used as long as it can maintain the positions of the inner reinforcing bars 40 and the outer reinforcing bars 41, such as connecting the main reinforcing bars 42 of the inner reinforcing bars 40 and the main reinforcing bars 43 of the outer reinforcing bars 41 with a steel wire.

[0045] FIG. 8 is a schematic vertical cross-sectional view of a steel shell 10 according to a second modified example of the composite segment 100 of the embodiment, as viewed from the side.

[0046] In the above, the outer reinforcing bars 41 are described as being composed of a plurality of main reinforcements 43 and a plurality of distribution reinforcements 45, but this is not limiting, and as shown in Fig. 8, the outer reinforcing bars 41 may be composed of only a plurality of main reinforcements 43. This is because the outer reinforcing bars 41 are arranged close to the skin plate 16, and the effect of the distribution reinforcements 45 as distribution reinforcements can be supplemented by the skin plate 16.

[0047] FIG. 9 is a schematic vertical cross-sectional view of a steel shell 10 according to a third modified example of the composite segment 100 of the embodiment, as viewed from the side.

[0048] 9, the outer reinforcing bars 41 may be composed of only a plurality of main reinforcements 43, which may be welded to the inner surface of the skin plate 16. In this way, the effect of the distribution reinforcement bars 45 as distribution reinforcement can be further complemented by the skin plate 16.

[0049] FIG. 10 is a schematic vertical cross-sectional view of a steel shell 10 according to a fourth modified example of the composite segment 100 of the embodiment, as viewed from the side.

[0050] In the fourth modified embodiment, the shape-retaining member 20 is located on the innermost side (Y1 side) within the steel shell 10 and is provided so as to connect the inner peripheral ends of a pair of main girders 11. A gap 60 is provided between the shape-retaining member 20 and the skin plate 16, and an inner reinforcing bar 40 arranged on the inner peripheral side and an outer reinforcing bar 41 arranged on the outer peripheral side are provided in the gap 60. By providing the shape-retaining member 20 so as to connect the inner peripheral ends of the pair of main girders 11 in this way, strength against loads applied in the axial direction AD can be improved compared to when the shape-retaining member 20 is provided further outward. Note that the position of the shape-retaining member 20 may be slightly offset from the innermost position within the steel shell 10, and substantially the same effect can be obtained.

[0051] As described above, the composite segment 100 according to the embodiment is a composite segment 100 that is connected in multiple ways in the circumferential direction CD and the axial direction AD to construct an earth retaining structure 200, and comprises a steel shell 10 and concrete 80 filled inside the steel shell 10, and the steel shell 10 has a pair of main girders 11 spaced apart in the axial direction AD, a skin plate 16 joined to the outer periphery of the main girders 11, a pair of joint plates 12 joined to both ends of the main girders 11 in the circumferential direction CD, and a first shear stop bar 51 extending in the circumferential direction CD, and the first shear stop bar 51 joined to the inner surface of the main girders 11.

[0052] In the composite segment 100 according to the embodiment, the first shear stop rebars 51 extending in the circumferential direction CD are joined to the inner surface of the main girder 11. In other words, the first shear stop rebars 51, which are concrete anchoring members, are provided on the inner surface of the main girder 11, where rigidity in the peeling direction of the concrete 80 is higher than that of the skin plate 16, thereby achieving a high anchoring effect for the concrete 80. Furthermore, because the concrete anchoring member is made up solely of the first shear stop rebars 51 extending in the circumferential direction CD, the number of rebars can be reduced, resulting in cost savings. Furthermore, providing the first shear stop rebars 51 improves strength against loads applied in the circumferential direction CD.

[0053] In addition, in the composite segment 100 according to the embodiment, the steel shell 10 has second shear stop bars 52 extending in the circumferential direction CD, and the second shear stop bars 52 are arranged at intervals in the axial direction AD and joined to the inner surface of the skin plate 16.

[0054] According to the composite segment 100 of the embodiment, by providing the second shear-stopping reinforcing bars 52 on the inner surface of the skin plate 16, a higher anchoring effect of the concrete 80 can be obtained.

[0055] In the composite segment 100 according to the embodiment, the steel shell 10 is joined between a pair of main girders 11 and has a plurality of shape-retaining members 20 extending in the axial direction AD.

[0056] According to the composite segment 100 of the embodiment, the steel shell 10 has a plurality of shape-retaining members 20. Therefore, the shape-retaining members 20 can improve the strength against the load applied in the axial direction AD, and the dimensions between the main girders 11 can be secured during the manufacturing of the composite segment 100.

[0057] In addition, in the composite segment 100 of the embodiment, inner reinforcing bars 40 are arranged on the inner side of the retaining structure 200 and are composed of multiple main reinforcements 42, or multiple main reinforcements 42 and multiple distribution reinforcements 44, and outer reinforcing bars 41 are arranged on the outer side of the retaining structure 200 and are composed of multiple main reinforcements 43 and multiple distribution reinforcements 44.

[0058] According to the composite segment 100 of the embodiment, the inner reinforcing bars 40 and the outer reinforcing bars 41 are provided in the concrete 80, thereby improving the strength of the concrete 80.

[0059] In the composite segment 100 according to the embodiment, a connecting reinforcing bar 46 that connects the inner reinforcing bar 40 and the outer reinforcing bar 41 is provided in the concrete 80 .

[0060] According to the composite segment 100 of the embodiment, the connecting reinforcing bars 46 that connect the inner reinforcing bars 40 and the outer reinforcing bars 41 are provided in the concrete 80. By doing so, the strength of the concrete 80 can be further improved.

[0061] In addition, in the composite segment 100 of the embodiment, the shape retention member 20 is arranged so that a gap 60 is formed between it and the skin plate 16, the outer reinforcing bar 41 is arranged in the gap 60, and the inner reinforcing bar 40 is arranged closer to the inner circumference of the retaining structure 200 than the shape retention member 20.

[0062] According to the composite segment 100 of the embodiment, the outer reinforcing bars 41 are arranged in the gaps 60 and are arranged near the skin plates 16. Therefore, the strength against the load applied in the circumferential direction CD by the reinforcing bars 45 can be supplemented by the skin plates 16, and the outer reinforcing bars 41 can be composed of only a plurality of main reinforcements 43.

[0063] In the composite segment 100 according to the embodiment, the shape-retaining member 20 is provided so as to connect the inner peripheral side ends of the pair of main girders 11 together.

[0064] According to the composite segment 100 of the embodiment, the shape retention member 20 is arranged to connect the inner peripheral ends of a pair of main girders 11, and therefore, the strength against loads applied in the axial direction AD can be improved compared to when the shape retention member 20 is arranged further outward. [Explanation of symbols]

[0065] 10 Steel shell, 11 Main girder, 12 Joint plate, 13 Connecting hole, 14 Connecting hole, 16 Skin plate, 20 Shape retaining member, 40 Inner reinforcing bar, 41 Outer reinforcing bar, 42 Main reinforcing bar, 43 Main reinforcing bar, 44 Distribution bar, 45 Distribution bar, 46 Connecting reinforcing bar, 51 First shear stop reinforcing bar, 52 Second shear stop reinforcing bar, 60 Gap, 80 Concrete, 81 Bolt box, 82 Bolt box, 100 Composite segment, 150 Segment ring, 200 Earth retaining structure.

Claims

1. A composite segment that constructs an earth retaining structure by being connected in multiple circumferential and axial directions of the earth retaining structure, Steel shell and and concrete filled inside the steel shell, The steel shell comprises: A pair of main beams spaced apart in the axial direction; a skin plate joined to the outer periphery of the main girder; A pair of joint plates joined to both ends of the main girder in the circumferential direction; a first shear stop bar extending in the circumferential direction; The first shear stop reinforcing bar is The main girder is joined to the inner surface thereof. The steel shell comprises: The structure has a plurality of shape-retaining members joined between the pair of main beams and extending in the axial direction, The concrete contains: A plurality of main reinforcements extending in the circumferential direction and spaced apart in the axial direction; A plurality of reinforcing bars extending in the axial direction and spaced apart in the circumferential direction; An inner reinforcing bar arranged on the inner periphery of the earth retaining structure and composed of the plurality of main reinforcements or the plurality of main reinforcements and the plurality of distribution reinforcements; An outer reinforcing bar arranged on the outer periphery of the retaining structure and composed of the plurality of main reinforcements and the plurality of distribution reinforcements; a connecting reinforcing bar that is separate from the plurality of reinforcing bars and connects the inner reinforcing bar and the outer reinforcing bar, Synthetic segment.

2. The first shear stop reinforcing bar is A plurality of the earth retaining structures are provided at intervals in the radial direction of the earth retaining structure. The synthetic segment of claim 1 .

3. The steel shell comprises: A second shear stop reinforcing bar extending in the circumferential direction is provided, The second shear retaining bar is A plurality of the axially spaced axially axially connected to the inner surface of the skin plate A synthetic segment according to claim 1 or 2.

4. The shape-retaining member is The skin plate is provided so as to form a gap therebetween, The outer reinforcing bar is disposed in the gap, The inner reinforcing bar is disposed on the inner circumferential side of the shape-retaining member. A synthetic segment according to any one of claims 1 to 3.

5. The shape-retaining member is The inner peripheral ends of the pair of main girders are connected to each other. A synthetic segment according to any one of claims 1 to 3.

6. The distribution bar of the inner reinforcing bar and the shape-retaining member are welded together. A synthetic segment according to any one of claims 1 to 5.

7. A composite segment formed by combining a plurality of composite segments according to any one of claims 1 to 6 in the circumferential direction and the axial direction. Earth retaining structures.

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