Segments and earth retaining structures

Abstract

This disclosure provides segments and earth retaining structures that, when using a one-touch type joint for the segments, can suppress costs such as manufacturing costs while maintaining watertightness provided by the joint plate. [Solution] The segment is a segment that constitutes a cylindrical body to be embedded as an earth retaining structure, and comprises a pair of main girders, a pair of joint plates, a skin plate that constitutes the outer surface of the cylindrical body, and concrete filled into a frame composed of the pair of main girders, a pair of joint plates, and a skin plate. At least one of the pair of joint plates is formed integrally with the skin plate and is bent relative to the skin plate to constitute a part of the end face of the segment in the circumferential direction, and both end faces of the segment in the circumferential direction have end faces in the central part in the radial direction of the cylindrical body where the concrete is exposed.

Description

Technical Field

[0001] The present disclosure relates to segments for forming earth retaining structures buried in the ground and earth retaining structures.

Background Art

[0002] Conventionally, one of the tunnel construction methods is the shield method. The shield method is a method in which, every time a tunneling machine installed in a shaft is advanced by a certain length, an arc-shaped segment is assembled in a ring shape behind it to construct a segment ring, and this is sequentially extended to form a cylindrical lining to construct a shield tunnel.

[0003] The segments used for tunnels or shafts as described above are formed by filling a filling material such as concrete inside a steel shell having a main girder forming the axial end face of the earth retaining structure, a joint plate forming the circumferential end face, and a skin plate forming the outer peripheral face (see, for example, Patent Document 1). By integrally forming the steel shell and the filling material, the segment ensures strength and rigidity and resists the earth pressure from the surrounding ground. In addition, the joint plate of the segment is used for water stop inside the earth retaining structure.

[0004] In the segment of Patent Document 1, bolts penetrate through the joint plate. And in the earth retaining structure of Patent Document 1, adjacent segments in the circumferential direction are fastened by fastening the joint plates of adjacent segments in the circumferential direction with bolts penetrating through the joint plate and nuts combined with the bolts. By the way, regarding the fastening of adjacent segments, in recent years, earth retaining structures in which segments are fastened by a so-called "one-touch" type joint by insertion or sliding have been proposed (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] In earth retaining structures having joint plates along the entire circumferential end face, such as the earth retaining structure described in Patent Document 1, when using a one-touch type joint, for example, it is necessary to embed the joint in concrete and provide the joint on the circumferential end face of the segment by making one or more holes near the radial center of the joint plate. Therefore, when using a one-touch type joint while maintaining watertightness with the joint plate, the joint plate must be processed to match the joint to be used in the segment manufacturing process before the concrete pouring process, which increases the number of steps in the segment manufacturing process and thus increases the manufacturing cost.

[0007] This disclosure solves the above-mentioned problems and provides segments and earth retaining structures that can suppress manufacturing costs and other costs while maintaining watertightness provided by joint plates when using a one-touch type joint for the segments. [Means for solving the problem]

[0008] The segment according to this disclosure is a segment that constitutes a cylindrical body to be embedded as an earth retaining structure, and comprises: 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 arranged at both ends of the pair of main girders in the circumferential direction and constituting a part of the end faces of the segment; a skin plate joined to the outer circumferential side of the pair of main girders in the radial direction of the cylindrical body and constituting the outer circumferential surface of the cylindrical body; and concrete filled into a frame composed of the pair of main girders, the pair of joint plates and the skin plate, wherein at least one of the pair of joint plates is formed integrally with the skin plate and is bent relative to the skin plate to constitute a part of the end face of the segment in the circumferential direction, and the end faces of the segment in the circumferential direction have end faces in the central part in the radial direction of the cylindrical body where concrete is exposed.

[0009] The earth retaining structure relating to this disclosure is formed by combining multiple of the above-mentioned segments in the circumferential and axial directions. [Effects of the Invention]

[0010] In the segments and retaining structures of this disclosure, at least one of a pair of joint plates is formed integrally with a skin plate and is bent relative to the skin plate to form a portion of the end face of the segment in the circumferential direction. Furthermore, both end faces of the segment in the circumferential direction have end faces where concrete is exposed in the central part in the radial direction of the cylindrical body. Because the segments and retaining structures have end faces where concrete is exposed in the central part in the radial direction of the cylindrical body, a one-touch type joint can be provided in this part, eliminating the need for additional manufacturing processes such as processing of joint plates for the joint. Therefore, when using a one-touch type joint in the segments and retaining structures, costs such as manufacturing costs can be suppressed while maintaining watertightness provided by the joint plates. [Brief explanation of the drawing]

[0011] [Figure 1]This is a conceptual diagram of the earth retaining structure according to Embodiment 1. [Figure 2] This is a conceptual diagram of the segment ring according to Embodiment 1, viewed in the axial direction. [Figure 3] This is a perspective view of an example of a segment according to Embodiment 1, viewed from the inner circumference. [Figure 4] This is a perspective view of an example of a segment according to Embodiment 1, taken from the outer periphery. [Figure 5] This is a side view of one example of a segment according to Embodiment 1, viewed in the circumferential direction. [Figure 6] This is a side view of another example of a segment according to Embodiment 1, viewed in the circumferential direction. [Figure 7] This is a front view showing an example of the internal structure of a segment according to Embodiment 1, as seen from the inner circumference side. [Figure 8] This is a front view showing another example of the internal structure of the segment according to Embodiment 1, as viewed from the inner circumference side. [Figure 9] This is an enlarged cross-sectional view schematically showing an example of the internal structure of both ends of a segment according to Embodiment 1. [Figure 10] This is a perspective view of the skin plate and joint plate of the segment according to Embodiment 1. [Figure 11] This is a perspective view of an example of a segment according to Embodiment 2, seen from the inner circumference side. [Figure 12] This is a side view of one example of a segment according to Embodiment 2, viewed in the circumferential direction. [Figure 13] This is a side view of another example of a segment according to Embodiment 2, viewed in the circumferential direction. [Figure 14] This is a front view showing an example of the internal structure of a segment according to Embodiment 2, as seen from the inner circumference side. [Figure 15] This is a front view showing another example of the internal structure of the segment according to Embodiment 2, as seen from the inner circumference side. [Figure 16] This is an enlarged cross-sectional view schematically showing an example of the internal structure of both ends of a segment according to Embodiment 2. [Figure 17]Perspective view of the skin plate and joint plate of the segment according to Embodiment 2. [Figure 18] Perspective view of an example of a segment according to Embodiment 3 as seen from the inner peripheral side. [Figure 19] Side view of one side of an example of a segment according to Embodiment 3 as seen in the circumferential direction. [Figure 20] Side view of the other side of an example of a segment according to Embodiment 3 as seen in the circumferential direction. [Figure 21] Enlarged cross-sectional view schematically showing an example of the internal structure of both ends of a segment according to Embodiment 3. [Figure 22] Enlarged cross-sectional view schematically showing another example of the internal structure of both ends of a segment according to Embodiment 3.

Mode for Carrying Out the Invention

[0012] Hereinafter, the segment and the earth retaining structure according to the embodiment will be described with reference to the drawings and the like. In the following drawings including FIG. 1, the relative dimensional relationships and shapes of each component may be different from the actual ones. Also, in the following drawings, those denoted by the same reference numerals are the same or corresponding ones, and this shall be common throughout the entire text of the specification. In addition, for the sake of easy understanding, terms indicating directions (for example, up, down, left, right, front, back, front and back, etc.) are appropriately used, but their notations are for the convenience of explanation and do not limit the arrangement, direction, and orientation of the device, instrument, or component, etc.

[0013] Embodiment 1. [Earth retaining structure 200] Figure 1 is a conceptual diagram of the earth retaining structure 200 according to Embodiment 1. In Figure 1, the axial direction AD 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. The radial direction RD represents the radial direction of the earth retaining structure 200, with the Y1 side representing the inner circumference of the earth retaining structure 200 and the Y2 side representing the outer circumference of the earth retaining structure 200. Furthermore, in the following descriptions of various members, when we say that they extend along the axial direction AD, the circumferential direction CD, or the radial direction RD, it is sufficient if they generally extend along that direction, and they do not need to strictly follow that direction.

[0014] The earth retaining structure 200 is used as an earth retaining wall, for example, in the lining of a tunnel, and is installed on the wall surface of an excavation hole formed by excavating the ground. The earth retaining structure 200 is installed underground and is used as an earth retaining wall in tunnels that make up subways, road tunnels, water and sewage tunnels, power and communication tunnels, utility tunnels, etc., or in shafts, etc. The earth retaining structure 200 may also be used as an earth retaining wall in other construction methods such as the press-in caisson method.

[0015] When the earth retaining structure 200 is used as an earth retaining wall in the shield tunneling method, the earth retaining structure 200 covers the excavated surface underground in the construction method such as the shield tunneling method and is installed within the ground 90. When the earth retaining structure 200 is used as an earth retaining wall in the press-in caisson method, the earth retaining structure 200 covers the excavated surface underground in the construction method such as the press-in method and is sunk into the ground 90.

[0016] The earth retaining structure 200 is a cylindrical body buried underground as an earth retaining structure. 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 in a shield tunneling method, the earth retaining structure 200 is formed to extend in the direction of travel of the shield machine. The earth retaining structure 200 is constructed to extend, for example, in the front-to-back direction. The earth retaining structure 200 is arranged underground, for example, so that the cylindrical axial direction AD extends horizontally, or so that it is inclined with respect to the horizontal direction. When the earth retaining structure 200 is used as an earth retaining wall in a press-in caisson method, the earth retaining structure 200 is arranged underground, for example, so that the cylindrical axial direction AD is in the up-and-down direction.

[0017] 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 overall, but is not limited to a cylindrical shape. The earth retaining structure 200 can be any cylindrical body, and may be formed in other shapes such as an oval shape, an oval shape, or a square shape with rounded corners when viewed in the axial direction AD.

[0018] The earth retaining structure 200 has at least one segment ring 110, or has multiple segment rings 110, and the multiple segment rings 110 are formed by continuously connecting them in the axial direction AD along which the tunnel extends. The earth retaining structure 200 is formed by combining multiple segments 100, which will be described later, in the circumferential direction CD and the axial direction AD.

[0019] [Segment ring 110] Figure 2 is a conceptual diagram of the segment ring 110 according to Embodiment 1, viewed in the axial direction AD. The segment ring 110 is a structure that covers the excavated surface underground. The segment ring 110 is formed in an annular shape when viewed in the axial direction AD, and is formed as a cylindrical body overall. The segment ring 110 is formed in a cylindrical shape, for example, but is not limited to a cylindrical shape. As long as the segment ring 110 is a cylindrical body, it may be formed in other shapes, such as an oval shape, an oval shape, or a square shape with rounded corners when viewed in the axial direction AD. The segment ring 110 may also be trapezoidal in shape, for example.

[0020] The earth retaining structure 200 is constructed by connecting multiple segment rings 110 at connecting parts 93 along the axial direction AD, as shown in Figure 1, in the direction in which the earth retaining structure 200 extends. The earth retaining structure 200 may also be composed of a single segment ring 110. 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 110 around the entire circumference (one ring) of the tunnel's cross-section. Therefore, in the earth retaining structure 200, the segment ring 110 constitutes one unit in the direction in which the tunnel extends.

[0021] The segment ring 110 is divided into multiple segments 100 in the circumferential direction CD. That is, as shown in Figures 1 and 2, multiple segments 100 are arranged in a ring, and adjacent segments 100 are connected to each other by connecting parts 92 to form the segment ring 110. In Figure 2, the segment ring 110 is shown with segments 100 of approximately equal size in the circumferential direction CD, but the size and shape of the segments 100 may be different depending on their installation position in the circumferential direction CD.

[0022] As shown in Figure 1, in the earth retaining structure 200, segment rings 110 adjacent to each other in the axial direction AD are assembled in a state where the positions of the segments 100 constituting the segment ring 110 are offset in the circumferential direction CD. For example, in the earth retaining structure 200, the segments 100 constituting the segment ring 110 are constructed in a staggered arrangement. However, the arrangement of the segments 100 is not limited to a staggered arrangement.

[0023] [Segment 100] Figure 3 is a perspective view of an example of segment 100 according to Embodiment 1, viewed from the inner circumference. Figure 4 is a perspective view of an example of segment 100 according to Embodiment 1, viewed from the outer circumference. Figure 5 is one side view of an example of segment 100 according to Embodiment 1, viewed in the circumferential direction CD. Figure 6 is the other side view of an example of segment 100 according to Embodiment 1, viewed in the circumferential direction CD. Figure 7 is a front view showing an example of the internal structure of segment 100 according to Embodiment 1, viewed from the inner circumference.

[0024] Figure 5 is an end view of segment 100 as seen in the direction of the white arrow A in Figure 3, along the circumferential direction CD, and Figure 6 is an end view of segment 100 as seen in the direction of the white arrow B in Figure 3, along the circumferential direction CD. Furthermore, in order to explain the internal structure of segment 100, the illustration of the right half of concrete 80 is omitted in Figure 7. Segment 100 will be explained using Figures 3 to 7.

[0025] Segment 100 constitutes a cylindrical body that is buried underground as a retaining wall structure. More specifically, segments 100 are arranged in a ring and connected to each other in the circumferential direction CD, forming a cylindrical segment ring 110 (see Figure 2) that covers the excavated surface underground. Multiple segments 100 are connected to the retaining wall structure 200 in the circumferential direction CD and the axial direction AD, thereby constructing the retaining wall structure 200. Segment 100 is a box-shaped structure made by combining multiple steel materials. When viewed in the axial direction AD of the segment ring 110, segment 100 is formed in an arc shape, and the overall shape is curved. A single segment 100 may also be referred to as a piece.

[0026] Segment 100 has a steel shell 10 and concrete 80 filled inside the steel shell 10. More specifically, segment 100 has a pair of main girders 11, a pair of joint plates 12, a skin plate 16, and concrete 80. Segment 100 is a composite structure of a steel shell 10 formed in a box shape by the main girders 11, joint plates 12 and skin plate 16, etc., and concrete 80 filled inside the steel shell 10 as a filler, with the steel shell 10 and concrete 80 being integrated into one structure. Segment 100 is, for example, a concrete-filled steel segment or a composite segment.

[0027] [Steel shell 10] As shown in Figures 3 to 7, the steel shell 10 of segment 100 has a pair of main girders 11 that extend in the circumferential direction CD of the cylindrical body, are spaced apart in the axial direction AD of the cylindrical body, and are arranged with their plate surfaces facing each other in the axial direction AD. The steel shell 10 also has a pair of joint plates 12 provided at both ends of the circumferential direction CD of each of the pair of main girders 11. The steel shell 10 also has a skin plate 16 positioned on the outer circumference side of the cylindrical body relative to the frame formed by the pair of main girders 11 and the pair of joint plates 12. The steel shell 10 is formed in a box shape by these pair of main girders 11, the pair of joint plates 12, and the skin plate 16.

[0028] The pair of main girders 11 are the parts where adjacent segments 100 abut each other in the axial AD of the earth retaining structure 200 and the segment ring 110, and are the parts where adjacent segments 100 are connected. The pair of main girders 11 are located at both ends of the segment 100 in the axial AD of the earth retaining structure 200 and the segment ring 110. 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 110, and form one end face and the other end face of the segment 100 in the axial AD.

[0029] 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 110. 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.

[0030] As shown in Figure 3, one of the pair of main girders 11 has multiple bolt holes 13 formed in it for connecting adjacent segments 100 connected in the axial direction AD. The number of bolt holes 13 is not limited to multiple; it may be one. As an example, one bolt hole 13 is formed in the central region and one in the regions at both ends of the circumferential direction CD. Note that the number of bolt holes 13 is not limited to the example shown.

[0031] Furthermore, as shown in Figure 3, the segment 100 has bolt boxes 81 in the concrete 80 at locations corresponding to the bolt holes 13. The bolt boxes 81 form a space in the segment 100 between the concrete 80 and the main girder 11 that exposes the bolt holes 13. The bolt boxes 81 serve as a working space used to fasten bolts (not shown) for fastening the main girders 11 of adjacent segments 100 together in the axial direction AD.

[0032] As shown in Figures 3, 4, and 7, of a pair of main girders 11, one main girder 11 has multiple bosses 14 formed on the other main girder 11 for connecting adjacent segments 100 connected in the axial direction AD. The bosses 14 are formed in the axial direction AD at positions opposite to the bolt holes 13. 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. Note that the number of bosses 14 is not limited to the illustrated example. Also, in the illustrated example, the bosses 14 are described as mounting holes corresponding to the bolt holes 13, but the bolt holes 13 may be formed instead of the bosses 14.

[0033] Two adjacent segments 100 in the axial direction AD are joined by butting the main girders 11 together and using bolts. The main girders 11 are joined using a bolt box 81, where bolts are inserted into bolt holes 13 and screwed into the female threads of bosses 14 provided on the main girders 11 of the adjacent segments 100. By screwing the shafts of the bolts inserted into the bolt holes 13 into the female threads of bosses 14 and fastening them, the two adjacent segments 100 in the axial direction AD are connected.

[0034] The number of bolt holes 13 and bosses 14 is not limited to the illustrated configuration and is determined by considering, for example, the size and shape of the segment 100. The above-described example of segment 100 connection is just one example. For example, adjacent segments 100 in the axial direction AD may be connected by fastening the main girders 11 together with bolts and nuts. Furthermore, the connection of adjacent segments 100 in the axial direction AD is not limited to a structure connected by bolts, etc., and may be done, for example, by a one-touch joint, or by using other well-known techniques.

[0035] The pair of joint plates 12 are the parts where adjacent segments 100 come into contact with each other in the circumferential direction CD of the earth retaining structure 200 and the segment ring 110. The pair of joint plates 12 are members that constitute both ends of the segment 100 in the circumferential direction CD. The pair of joint plates 12 are positioned at both ends of the pair of main girders 11 in the circumferential direction CD and constitute a part of the end face of the segment 100.

[0036] The joint plate 12 is used, for example, to stop water from entering the segment 100. The joint plate 12 is made of a plate-shaped steel sheet. As shown in Figures 5 and 6, the joint plate 12 is formed in a rectangular shape when viewed in the circumferential direction CD. 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 girder 11 is the circumferential direction CD. As shown in Figures 5 and 6, the joint plate 12 is provided only on the outer circumference side of the segment 100 in the radial direction RD.

[0037] The joint plate 12 is positioned at both ends of the circumferential CD of the 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 segment 100.

[0038] In the segment 100 according to Embodiment 1, one of the pair of joint plates 12, joint plate 12a, is integrally formed with the skin plate 16. In addition, in the segment 100 according to Embodiment 1, the other joint plate 12b of the pair of joint plates 12 is formed separately from the skin plate 16 and is welded and joined to the skin plate 16.

[0039] A seal groove 12d may be formed in the joint plate 12, in which a seal member 12e is placed. In the segment 100 shown in Figures 5 and 6, a pair of joint plates 12 have a seal groove 12d that extends in the axial direction AD. The seal groove 12d is a groove recessed inward from the end face of the segment 100 in the circumferential direction CD, and is a groove in which a waterproof seal member 12e is placed.

[0040] The seal groove 12d is formed to extend in the axial direction AD of the segment ring 110. The seal groove 12d is also formed on the outer circumference (Y2 side) of the segment ring 110 in the radial direction RD. A seal member 12e is fitted into the seal groove 12d. The seal member 12e is, for example, a water-swellable seal material, but is not limited to a water-swellable seal material.

[0041] The skin plate 16 is joined to the outer circumference of the pair of main girders 11 in the radial direction RD of the cylindrical body and constitutes the outer surface of the cylindrical body. The skin plate 16 is a plate-like member facing the ground side of the 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 in a plan view in the axial direction AD, and in a rectangular shape in a side view in the radial direction RD.

[0042] As shown in Figures 4 and 5, the skin plate 16 is joined to the frame, such as the pair of main girders 11 and the pair of joint plates 12, so as to close the openings on the end faces facing the ground. That is, the skin plate 16 is provided on the outer periphery of the main girders 11 and joint plates 12 that constitute the segment 100. When the 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.

[0043] [Joint section 15] Segment 100 is provided with joint portions 15 at both ends of segment 100 in the circumferential direction CD. The joint portions 15 are connecting members used in the segment ring 110 to connect adjacent segments 100 in the circumferential direction CD.

[0044] The end faces of the segment 100 in the circumferential direction CD have end face portions 18 in the central part in the radial direction RD of the cylindrical body where concrete 80 is exposed. In the segment 100 according to Embodiment 1, at both end faces of the segment 100 in the circumferential direction CD, joint plates 12 are arranged on the outer circumference side in the radial direction RD, and the central part and inner circumference side in the radial direction RD are composed of end face portions 18.

[0045] The joint portion 15 is provided on the end face portion 18. That is, the end face portion 18 of the segment 100 is provided with a joint portion 15 used as a joint to connect adjacent segments 100 in the circumferential direction CD. The joint portion 15 is embedded in the end face portion 18 of the segment 100. The joint portion 15 is provided in the central part of the segment 100 in the radial direction RD.

[0046] The joint portion 15 is composed of a first joint portion 15a and a second joint portion 15b. The term "joint portion 15" is a collective term for the first joint portion 15a and the second joint portion 15b. The joint portion 15 is connected to the first joint portion 15a and the second joint portion 15b by combining the first joint portion 15a of one segment 100 and the second joint portion 15b of the other segment 100 of two segments 100 adjacent to each other in the circumferential direction CD.

[0047] As an example, the joint portion 15 is connected to the first joint portion 15a and the second joint portion 15b by sliding the first joint portion 15a and the second joint portion 15b relative to each other in the axial direction AD. For example, in order to facilitate the combination of the first joint portion 15a and the second joint portion 15b by sliding them relative to each other in the axial direction AD, the segments 100 are arranged such that the positions of the first joint portion 15a and the second joint portion 15b are opposite at both ends of the segment 100 in the circumferential direction CD, as shown in Figure 7.

[0048] The configuration of the joint portion 15 is not limited to the configuration shown. For example, the first joint portion 15a may be inserted into the second joint portion 15b in the circumferential direction CD, thereby combining the first joint portion 15a and the second joint portion 15b and connecting them. The configuration of the joint portion 15 is not limited to the configuration of the first joint portion 15a and the second joint portion 15b shown. Furthermore, the joint portion 15 only needs to be provided at the end face of the segment 100 in the circumferential direction CD and in the central part of the segment 100 in the radial direction RD, and the position of the axial direction AD and the number of joint portions 15 are not limited to the illustrated example.

[0049] The first joint portion 15a is provided so as to protrude from, for example, the end face portion 18. The second joint portion 15b is provided inside the end face portion 18 so as to be exposed to the end face portion 18. As an example, as shown in Figure 3, a joint groove portion 17 extending in the axial direction AD is formed in the end face portion 18 of the segment 100, and the second joint portion 15b may be provided inside the groove portion 17.

[0050] When connecting segments 100 in the circumferential direction of the tunnel, one segment 100 to be connected is provided with a second joint portion 15b, and the other segment 100 is provided with a first joint portion 15a. At least a portion of the segment ring 110 connects the segments 100 by inserting a portion of the first joint portion 15a into the second joint portion 15b. Furthermore, the segments 100 can also be applied to general bolted connections.

[0051] [Vertical rib 19] The steel shell 10 of segment 100 may have so-called longitudinal ribs 19, as shown in Figure 7. The longitudinal ribs 19 are plate-like members of steel that connect a pair of main girders 11 and resist the tensile force acting on the main girders 11. As shown in Figure 7, the longitudinal ribs 19 may be joined to the inner surface of the skin plate 16. The longitudinal ribs 19 protrude radially RD from the skin plate 16.

[0052] The longitudinal ribs 19, when installed on the skin plate 16, prevent the skin plate 16 from deforming in a way that causes it to bulge out. The longitudinal ribs 19 are plate-shaped members and are arranged to extend along the axial direction AD such that the axial direction AD is the longitudinal direction. For example, both ends of the longitudinal rib 19 along the axial direction AD are joined to both or one of the pair of main girders 11. The longitudinal ends of the longitudinal rib 19 may be spaced apart from the pair of main girders 11.

[0053] [Concrete 80] The concrete 80 is filled into a frame structure composed of a pair of main girders 11, a pair of joint plates 12, and a skin plate 16. The segment 100 is a so-called "concrete-filled segment" in which the concrete 80 is filled.

[0054] Figure 8 is a front view showing another example of the internal structure of segment 100 according to Embodiment 1, viewed from the inner circumference. Note that, in order to explain the internal structure of segment 100, the right half of the concrete 80 is omitted from Figure 8. Segment 100 is, for example, a concrete-filled steel segment or a composite segment.

[0055] As shown in Figure 8, the segment 100 may comprise a steel shell 10 filled with concrete 80, a reinforcing cage 40 assembled with reinforcing bars 45 arranged inside the steel shell 10, and the concrete 80 filled inside the steel shell 10. The segment 100 is a composite structure of a box-shaped steel shell 10, a reinforcing cage 40, and concrete 80 filled inside the steel shell 10 as a filler, and the steel shell 10, the reinforcing cage 40, and the concrete 80 may be integrated into a single structure.

[0056] [Reinforced concrete cage 40] As shown in Figure 8, the segment 100 may include a reinforcing cage 40 within the concrete 80. The reinforcing cage 40 is made by pre-assembling reinforcing bars 45 to be placed within the concrete 80. The reinforcing cage 40 is formed in a cage shape by combining multiple reinforcing bars 45. The reinforcing cage 40 may be formed in a box shape or in a plate shape. The reinforcing cage 40 is formed by tying together multiple reinforcing bars 45, for example, using welding or binding wire.

[0057] The reinforcing cage 40 has multiple reinforcing bars 45. More specifically, the reinforcing cage 40 has main reinforcing bars 41 extending in the circumferential direction CD inside the steel shell 10, and distribution reinforcing bars 43 extending in the axial direction AD inside the steel shell 10. The reinforcing bars 45 are a collective term for the main reinforcing bars 41 and the distribution reinforcing bars 43. The reinforcing cage 40 is assembled into a cage shape by joining the main reinforcing bars 41 and the distribution reinforcing bars 43.

[0058] The main reinforcement bars 41 are reinforcing bars 45 that bear the axial force and bending moment of the segment 100. The main reinforcement bars 41 are provided so as to extend in the circumferential direction CD of the segment 100. The main reinforcement bars 41 are formed in an arc shape when viewed in the axial direction AD of the segment 100. However, the shape of the main reinforcement bars 41 is not limited to an arc shape; in the case of the oval-shaped earth retaining structure 200 described above, any shape that conforms to the shape of the earth retaining structure 200 when viewed in the axial direction AD of the segment 100 is acceptable.

[0059] The reinforcing cage 40 has multiple main reinforcements 41 along the axial direction AD of the segment 100, and the multiple main reinforcements 41 are spaced apart in the axial direction AD. In addition, the main reinforcements 41 are arranged, for example, on the outer and inner sides in the radial direction RD. In the reinforcing cage 40, for example, the multiple main reinforcements 41 are spaced apart from each other in the radial direction RD. Figure 8 shows an example in which the reinforcing cage 40 has multiple main reinforcements 41 in the axial direction AD, but the number of main reinforcements 41 is not limited to the example shown. In the axial direction AD, the number of main reinforcements 41 may be multiple or single, depending on, for example, the size of the segment 100. Also, in the radial direction RD, the number of main reinforcements 41 may be multiple or single, depending on, for example, the size of the segment 100.

[0060] The distribution reinforcement bars 43 are reinforcing bars 45 that surround multiple main reinforcement bars 41 in the axial direction AD and radial direction RD to restrain them. The distribution reinforcement bars 43 have the function of so-called distribution reinforcement bars, as well as the function of hoop reinforcement bars or stirrups. For example, the distribution reinforcement bars 43 transmit the load applied to the main reinforcement bars 41 to adjacent main reinforcement bars 41, distributing the load. In addition, the distribution reinforcement bars 43 resist the shear force acting on the segment 100.

[0061] The distribution reinforcement bars 43 are formed in a ring shape and are formed in a square shape so as to surround the multiple main reinforcement bars 41 from the outside. The distribution reinforcement bars 43 may also be formed in a square shape with a part of it cut out. The multiple main reinforcement bars 41 are fixed inside the ring-shaped distribution reinforcement bars 43. However, if the necessary strength for the segment 100 can be ensured, the multiple main reinforcement bars 41 may also be fixed outside the ring-shaped distribution reinforcement bars 43.

[0062] The distribution reinforcement bars 43 may be formed by bending a single steel bar, or by combining multiple steel bars. The distribution reinforcement bars 43 connect between multiple parallel main reinforcement bars 41 to form a single reinforcing cage 40. Multiple distribution reinforcement bars 43 are arranged in the reinforcing cage 40 along the longitudinal direction of the main reinforcement bars 41, that is, along the circumferential direction CD. Note that the number of distribution reinforcement bars 43 is not limited to multiple, and may be one.

[0063] [Skin plate 16 and joint plate 12] Figure 9 is a schematic enlarged cross-sectional view showing an example of the internal structure of both ends of the segment 100 according to Embodiment 1. Figure 10 is a perspective view of the skin plate 16 and joint plate 12 of the segment 100 according to Embodiment 1. The relationship between the skin plate 16 and joint plate 12 used in the segment 100 according to Embodiment 1 will be explained using Figures 9 and 10.

[0064] Of the pair of joint plates 12, at least one joint plate 12 is formed integrally with the skin plate 16 and is bent relative to the skin plate 16 to form a part of the end face of the segment 100 in the circumferential direction CD.

[0065] In the segment 100 according to Embodiment 1, one of the pair of joint plates 12, joint plate 12a, is formed integrally with the skin plate 16. Furthermore, in the segment 100 according to Embodiment 1, joint plate 12a is bent relative to the skin plate 16 at one end of the skin plate 16 in the circumferential direction CD, forming a part of one end face of the segment 100 in the circumferential direction CD.

[0066] The joint plate 12a and the skin plate 16 are formed from a single component. The joint plate 12a and the skin plate 16 are a single component bent at the corner 12c. The joint plate 12a and the skin plate 16 are integrally formed via the corner 12c. The corner 12c is the bent portion. The joint plate 12a constitutes a part of the end face of the segment 100 facing the circumferential direction CD, and the skin plate 16 constitutes the outer circumferential surface of the segment 100 facing the radial direction RD.

[0067] In the segment 100 according to Embodiment 1, of the pair of joint plates 12, the other joint plate 12b is fixed to the skin plate 16 by welding at the other end of the skin plate 16 in the circumferential direction CD. The joint plate 12b, which is welded to the skin plate 16, constitutes a part of the other end face of the segment 100 in the circumferential direction CD. In the segment 100 according to Embodiment 1, of the pair of joint plates 12, the other joint plate 12b is a separate component from the skin plate 16 and is fixed to the skin plate 16 by welding or the like.

[0068] A seal groove 12d may be formed in either the joint plate 12a or the joint plate 12b, or a seal groove 12d may be formed in both the joint plate 12a and the joint plate 12b. The seal member 12e is placed in the seal groove 12d as described above. Alternatively, the seal groove 12d may not be formed in the joint plate 12a and the joint plate 12b, and the seal member 12e may be directly attached to the joint plate 12a and the joint plate 12b.

[0069] [Effects of Segment 100] In segment 100, at least one of the pair of joint plates 12, 12a, is integrally formed with the skin plate 16 and is bent relative to the skin plate 16 to form a part of the end face of segment 100 in the circumferential direction CD. Furthermore, both end faces of segment 100 in the circumferential direction CD have end face portions 18 in the central part of the radial direction RD of the cylindrical body where concrete 80 is exposed. Because segment 100 has end face portions 18 in the central part of the radial direction RD of the cylindrical body where concrete 80 is exposed, a one-touch joint portion 15 can be provided in this portion, eliminating the need for additional manufacturing processes such as processing of the joint plate 12 for the joint portion 15. Therefore, when using a one-touch joint portion 15 in segment 100, it is possible to suppress manufacturing costs and other costs while maintaining watertightness provided by the joint plate 12.

[0070] Furthermore, in segment 100, at least one of the pair of joint plates 12, joint plate 12a, is formed integrally with the skin plate 16 and is bent relative to the skin plate 16 to form a part of the end face of segment 100 in the circumferential direction CD. The joint plate 12a can be formed by bending the steel material on the end side of the skin plate 16 in the circumferential direction CD. Therefore, with this configuration, segment 100 has a simpler manufacturing process and lower manufacturing costs compared to a case where the joint plate 12 and the skin plate 16 are formed as separate components and then fixed by welding or the like. In addition, with this configuration, the corner portion 12c between the joint plate 12a and the skin plate 16 is formed integrally with the joint plate 12 and the skin plate 16, so there is no risk of a gap being formed between the joint plate 12a and the skin plate 16, and the reliability of watertightness is improved.

[0071] Furthermore, one of the pair of joint plates 12, joint plate 12a, is formed integrally with the skin plate 16. This joint plate 12a is bent relative to the skin plate 16 at one end of the skin plate 16 in the circumferential direction CD, forming a part of one end face of the segment 100 in the circumferential direction CD. The other joint plate 12b of the pair of joint plates 12 is fixed to the skin plate 16 by welding at the other end of the skin plate 16 in the circumferential direction CD, forming a part of the other end face of the segment 100 in the circumferential direction CD.

[0072] The joint plate 12a can be formed by bending the steel material on the end side of the skin plate 16 in the circumferential direction CD. Therefore, with this configuration, the segment 100 has a simpler manufacturing process and lower manufacturing costs compared to a case where the joint plate 12 and the skin plate 16 are formed as separate components and then fixed by welding or the like. In addition, with this configuration, the corner portion 12c between the joint plate 12a and the skin plate 16 of the segment 100 is formed integrally with the joint plate 12 and the skin plate 16, so there is no risk of a gap being formed between the joint plate 12a and the skin plate 16, and the reliability of watertightness is improved.

[0073] Furthermore, depending on the configuration of the seal groove 12d, for example, it may be better to configure the skin plate 16 and the joint plate 12 as separate components and to pre-process the seal groove 12d, etc., into the joint plate 12 before fixing the positional relationship between the joint plate 12 and the skin plate 16. Even in such cases, since the segment 100 has a skin plate 16 and a joint plate 12b that is fixed by welding, the joint plate 12b can be pre-processed before fixing the positional relationship between the joint plate 12b and the skin plate 16, making it easier to manufacture the segment 100.

[0074] Furthermore, a seal groove 12d extending in the axial direction AD is formed in the pair of joint plates 12. The seal groove 12d is a groove recessed inward from the end face of the segment 100 in the circumferential direction CD, and is a groove in which a waterproof seal member 12e is placed. By placing the seal member 12e in the seal groove 12d, the segment 100 can achieve more reliable watertightness compared to when the seal member 12e is not provided.

[0075] Furthermore, the end face portion 18 is provided with a joint portion 15 used as a joint for connecting adjacent segments 100 in the circumferential direction CD. By providing the joint portion 15 on the end face portion 18 of the segment 100, processing of the joint plate 12 is not required compared to the case where the joint portion 15 is provided on the joint plate 12, thereby reducing manufacturing costs and other costs. In addition, by providing the joint portion 15 on the end face portion 18 of the segment 100, it becomes easier to fix adjacent segments 100 together compared to, for example, fixing the joint plates 12 of adjacent segments 100 in the circumferential direction CD with bolts and nuts. With this configuration, the earth retaining structure 200 can be made easier to fix adjacent segments 100 together compared to bolting adjacent segments 100 together, thereby speeding up the work process.

[0076] The earth retaining structure 200 is formed by combining multiple segments 100 with the above configuration in the circumferential direction CD and the axial direction AD. Therefore, the earth retaining structure 200 can exert the effects of the segment 100 according to the above-described embodiment 1.

[0077] Embodiment 2. Figure 11 is a perspective view of an example of segment 100 according to Embodiment 2, viewed from the inner circumference. Figure 12 is a side view of an example of segment 100 according to Embodiment 2, viewed in the circumferential direction CD. Figure 13 is a side view of an example of segment 100 according to Embodiment 2, viewed in the circumferential direction CD. Figure 14 is a front view showing an example of the internal structure of segment 100 according to Embodiment 2, viewed from the inner circumference. Figure 15 is a front view showing another example of the internal structure of segment 100 according to Embodiment 2, viewed from the inner circumference. Figure 16 is a schematic enlarged cross-sectional view showing an example of the internal structure of both ends of segment 100 according to Embodiment 2. Figure 17 is a perspective view of the skin plate 16 and joint plate 12 of segment 100 according to Embodiment 2.

[0078] Figure 12 is an end view of segment 100 as seen in the circumferential direction CD in the direction of the white arrow A in Figure 11, and Figure 13 is an end view of segment 100 as seen in the circumferential direction CD in the direction of the white arrow B in Figure 11. In order to explain the internal structure of segment 100, the right half of the concrete 80 is omitted from Figures 14 and 15. Components having the same function and operation as segment 100 according to Embodiment 1 are given the same reference numerals and their descriptions are omitted. Hereinafter, using Figures 11 to 17, Embodiment 2 will be explained focusing on the differences between Embodiment 2 and Embodiment 1, and components not described in Embodiment 2 are the same as in Embodiment 1.

[0079] The segment 100 of Embodiment 2 differs from the segment 100 of Embodiment 1 in the configuration of the joint plate 12 and the skin plate 16.

[0080] As shown in Figures 11 to 13, 16 and 17, in the segment 100 according to Embodiment 2, each joint plate 12a of the pair of joint plates 12 is formed integrally with the skin plate 16. Furthermore, in the segment 100 according to Embodiment 2, each joint plate 12a is bent relative to the skin plate 16 at both ends of the skin plate 16 in the circumferential direction CD, forming a part of the end face of the segment 100 in the circumferential direction CD.

[0081] As shown in Figures 16 and 17, the pair of joint plates 12a and the skin plate 16 are formed from a single component. The joint plates 12a and the skin plate 16 are a single component bent at the corner portion 12c. The joint plates 12a and the skin plate 16 are integrally formed via the corner portion 12c. The pair of joint plates 12a constitute both end faces of the segment 100 facing the circumferential direction CD, and the skin plate 16 constitutes the outer circumferential surface of the segment 100 facing the radial direction RD.

[0082] The segment 100 according to Embodiment 2 may be a concrete-filled steel segment for shield tunneling, as shown in Figure 14. Alternatively, the segment 100 according to Embodiment 2 may be, for example, a concrete-filled steel segment or a composite segment, as shown in Figure 15.

[0083] [Effects of Segment 100] In the segment 100 according to Embodiment 2, each joint plate 12a of the pair of joint plates 12 is formed integrally with the skin plate 16. The pair of joint plates 12a are bent relative to the skin plate 16 at both ends of the skin plate 16 in the circumferential direction CD, forming a part of the end face of the segment 100 in the circumferential direction CD.

[0084] A pair of joint plates 12a can be formed by bending the steel material on both ends of the skin plate 16 in the circumferential direction CD. Therefore, with this configuration, the segment 100 has a simpler manufacturing process and lower manufacturing costs compared to a case where the joint plate 12 and the skin plate 16 are formed as separate components and then fixed by welding or the like. In addition, with this configuration, the corner portion 12c between the joint plate 12a and the skin plate 16 is formed integrally with the joint plate 12 and the skin plate 16, so there is no risk of a gap being formed between the joint plate 12a and the skin plate 16, and the reliability of watertightness is improved.

[0085] The segment 100 according to Embodiment 2 can achieve the same effects as the segment 100 according to Embodiment 1. For example, since the segment 100 has an end face portion 18 in the central part in the radial direction RD where concrete 80 is exposed, a one-touch joint portion 15 can be provided in this portion, and there is no need to provide additional manufacturing processes such as processing of the joint plate 12 for the joint portion 15. Therefore, when using a one-touch joint portion 15 in the segment 100, it is possible to suppress costs such as manufacturing costs while maintaining watertightness provided by the joint plate 12.

[0086] The earth retaining structure 200 is formed by combining multiple segments 100 with the above configuration in the circumferential direction CD and the axial direction AD. Therefore, the earth retaining structure 200 can exert the effects of the segment 100 according to the second embodiment described above.

[0087] Embodiment 3. Figure 18 is a perspective view of an example of segment 100 according to Embodiment 3, viewed from the inner circumference. Figure 19 is a side view of an example of segment 100 according to Embodiment 3, viewed in the circumferential direction CD. Figure 20 is a side view of an example of segment 100 according to Embodiment 3, viewed in the circumferential direction CD. Figure 21 is a schematic enlarged cross-sectional view showing an example of the internal structure of both ends of segment 100 according to Embodiment 3. Figure 22 is a schematic enlarged cross-sectional view showing another example of the internal structure of both ends of segment 100 according to Embodiment 3.

[0088] Figure 19 is an end view of segment 100 as seen in the circumferential direction CD in the direction of the white arrow A in Figure 18, and Figure 20 is an end view of segment 100 as seen in the circumferential direction CD in the direction of the white arrow B in Figure 18. Components having the same function and operation as segment 100 according to Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted. Hereinafter, using Figures 18 to 22, Embodiment 3 will be described focusing on the differences between Embodiment 1 and Embodiment 2, and components not described in Embodiment 3 are the same as those in Embodiment 1 and Embodiment 2.

[0089] The segment 100 according to Embodiment 3 further comprises a pair of inner circumferential joint plates 22 arranged at both ends of a pair of main girders 11 in the circumferential direction CD, and forming part of the end face of the segment 100. The inner circumferential joint plates 22 are used, for example, to stop water from entering the segment 100.

[0090] The pair of inner circumferential joint plates 22 are positioned on the inner side in the radial direction RD, relative to the joint plate 12 which is positioned on the outer side. The pair of inner circumferential joint plates 22 are positioned with a gap between them and the pair of joint plates 12 in the radial direction RD.

[0091] The end faces of the segment 100 according to Embodiment 3 have end face portions 18 in which concrete 80 is exposed between a pair of joint plates 12 and a pair of inner circumferential joint plates 22 in the radial direction RD. The end faces of the segment 100 according to Embodiment 3 are provided with joint portions 15 at the end face portions 18.

[0092] The inner circumferential joint plate 22 is made of a plate-shaped steel sheet. As shown in Figures 19 and 20, the inner circumferential joint plate 22 is formed in a rectangular shape when viewed in the circumferential direction CD. The inner circumferential joint plate 22 is formed to extend in the axial direction AD and the radial direction RD. The inner circumferential joint plate 22 is spanned and fixed between the longitudinal ends of a pair of main girders 11. As shown in Figures 19 and 20, the inner circumferential joint plate 22 is provided only on the inner circumferential side of the segment 100 in the radial direction RD.

[0093] An inner circumferential joint plate 22 may have an inner circumferential seal groove 22d formed therein, in which an inner circumferential seal member 22e is positioned. In the segment 100 shown in Figures 19 and 20, a pair of inner circumferential joint plates 22 have an inner circumferential seal groove 22d extending in the axial direction AD. The inner circumferential seal groove 22d is a groove recessed inward from the end face of the segment 100 in the circumferential direction CD, and is a groove in which a waterproof inner circumferential seal member 22e is positioned.

[0094] The inner circumferential seal groove 22d is formed to extend in the axial direction AD of the segment ring 110. Furthermore, the inner circumferential seal groove 22d is formed on the inner circumferential side (Y1 side) of the segment ring 110 in the radial direction RD. An inner circumferential seal member 22e is fitted into the inner circumferential seal groove 22d. The inner circumferential seal member 22e is, for example, a water-swellable seal material, but is not limited to a water-swellable seal material. Alternatively, the inner circumferential seal groove 22d may not be formed on the inner circumferential joint plate 22, and the inner circumferential seal member 22e may be directly attached to the inner circumferential joint plate 22.

[0095] In the third embodiment, as shown in Figure 21, only one of the pair of joint plates 12a of the segment 100 may be formed integrally with the skin plate 16. That is, the segment 100 shown in Figure 21 may be the segment 100 of the first embodiment with an inner circumferential joint plate 22. In the third embodiment, as shown in Figure 22, both of the pair of joint plates 12a of the segment 100 may be formed integrally with the skin plate 16. That is, the segment 100 shown in Figure 22 may be the segment 100 of the second embodiment with an inner circumferential joint plate 22.

[0096] [Effects of Segment 100] The segment 100 according to Embodiment 3 further comprises a pair of inner circumferential joint plates 22 arranged at both ends of a pair of main girders 11 in the circumferential direction CD, and forming part of the end face of the segment 100. The pair of inner circumferential joint plates 22 are spaced apart from the pair of joint plates 12 in the radial direction RD. The end faces of the segment 100 have end face portions 18 where concrete 80 is exposed between the pair of joint plates 12 and the pair of inner circumferential joint plates 22 in the radial direction RD.

[0097] Segment 100 has an exposed concrete end face portion 18 in the central part of the radial direction RD of the cylindrical body, between a pair of joint plates 12 and a pair of inner circumferential joint plates 22 in the radial direction RD. Because segment 100 has an exposed concrete end face portion 18, a one-touch type joint portion 15 can be provided in this portion, eliminating the need for additional manufacturing processes such as processing of the joint plates 12 for the joint portion 15. Therefore, when using a one-touch type joint portion 15 in segment 100, it is possible to suppress manufacturing costs and other costs while maintaining watertightness with the joint plates 12 and inner circumferential joint plates 22. In addition, by having an inner circumferential joint plate 22 on the inner side of the radial direction RD, segment 100 can improve watertightness on the inner side.

[0098] In the segment 100 according to Embodiment 3, a pair of inner circumferential joint plates 22 have an inner circumferential seal groove 22d that extends in the axial direction AD. The inner circumferential seal groove 22d is a groove recessed inward from the end face of the segment 100 in the circumferential direction CD, and is a groove in which a waterproof inner circumferential seal member 22e is arranged. By arranging the inner circumferential seal member 22e in the inner circumferential seal groove 22d, the segment 100 can achieve more reliable watertightness compared to the case where the inner circumferential seal member 22e is not provided.

[0099] The segment 100 according to Embodiment 3 can achieve the same effects as the segments 100 according to Embodiments 1 and 2. For example, since the segment 100 has an end face portion 18 in the central part in the radial direction where concrete 80 is exposed, a one-touch joint portion 15 can be provided in this portion, and there is no need to provide additional manufacturing processes such as processing of the joint plate 12 for the joint portion 15. Therefore, when using a one-touch joint portion 15 in the segment 100, it is possible to suppress costs such as manufacturing costs while maintaining watertightness provided by the joint plate 12.

[0100] The earth retaining structure 200 is formed by combining multiple segments 100 with the above configuration in the circumferential direction CD and the axial direction AD. Therefore, the earth retaining structure 200 can exert the effects of the segment 100 according to the above-described embodiment 3.

[0101] The configurations shown in the above embodiments are merely examples, and can be combined with other known technologies. It is also possible to omit or modify parts of the configuration without departing from the gist of the invention.

[0102] The segment 100 described above may also include combinations of the features shown in the following appendices 1 to 8. These combinations are shown below. [Note 1] A segment that constitutes a cylindrical body buried as an earth retaining 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, In the circumferential direction, a pair of joint plates are arranged at both ends of the pair of main girders and constitute a part of the end face of the segment, In the radial direction of the cylindrical body, it is joined to the outer circumference of the pair of main girders, and the skin plate that constitutes the outer surface of the cylindrical body, Concrete is filled into the frame structure, which is composed of the pair of main girders, the pair of joint plates, and the skin plate. Equipped with, Of the pair of joint plates, at least one of the joint plates is It is formed integrally with the skin plate and is bent relative to the skin plate to form a part of the end face of the segment in the circumferential direction. The end faces of the segment in the circumferential direction are A segment having an end face portion in the central radial portion of the cylindrical body where the concrete is exposed. [Note 2] Of the pair of joint plates, one of the joint plates is It is formed integrally with the skin plate, and at one end of the skin plate in the circumferential direction, it is bent relative to the skin plate to form a part of one end face of the segment in the circumferential direction. Of the pair of joint plates, the other joint plate is The segment described in Appendix 1, which is fixed to the other end of the skin plate in the circumferential direction by welding and constitutes a part of the other end face of the segment in the circumferential direction. [Note 3] Each of the pair of joint plates is The segment described in Appendix 1, which is formed integrally with the skin plate and is bent relative to the skin plate at both ends of the skin plate in the circumferential direction to constitute a part of the end face of the segment in the circumferential direction. [Note 4] In the circumferential direction, the pair of main girders are arranged at both ends and further comprise a pair of inner circumferential joint plates that form part of the end face of the segment. The pair of inner circumferential joint plates are, In the radial direction, it is arranged with a gap between it and the pair of joint plates. The two end faces of the aforementioned segment are A segment according to any one of the appendices 1 to 3, having the end face portion in which the concrete is exposed between the pair of joint plates and the pair of inner circumferential joint plates in the radial direction. [Note 5] The pair of joint plates mentioned above include: A seal groove extending in the axial direction is formed therein. The aforementioned seal groove is The segment according to any one of the appendices 1 to 4, wherein the groove is recessed inward from the end face of the segment in the circumferential direction, and the groove is in which a waterproof sealing member is arranged. [Note 6] The pair of inner circumferential joint plates include: An inner circumferential sealing groove extending in the axial direction is formed therein. The inner circumferential sealing groove is The segment according to Appendix 4, wherein the groove is recessed inward from the end face of the segment in the circumferential direction, and the groove is in which a waterproof inner circumferential sealing member is arranged. [Note 7] The end face portion has, A segment according to any one of the appendices 1 to 6, which is provided with a joint portion used as a joint for connecting adjacent segments in the circumferential direction. [Note 8] A retaining structure formed by combining multiple segments described in any one of the appendices 1 to 7 in the circumferential and axial directions. [Explanation of Symbols]

[0103] 10 Steel shell, 11 Main girder, 12 Joint plate, 12a Joint plate, 12b Joint plate, 12c Corner section, 12d Seal groove, 12e Seal member, 13 Bolt hole, 14 Boss, 15 Joint section, 15a First joint section, 15b Second joint section, 16 Skin plate, 17 Groove section, 18 End face section, 19 Vertical rib, 22 Inner circumference joint plate, 22d Inner circumference seal groove, 22e Inner circumference seal member, 40 Reinforcement cage, 41 Main reinforcement, 43 Distribution reinforcement, 45 Reinforcement, 80 Concrete, 81 Bolt box, 90 Ground, 91 Hollow section, 92 Connecting section, 93 Connecting section, 100 Segment, 110 Segment ring, 200 Earth retaining structure.

Claims

1. A segment that constitutes a cylindrical body buried as an earth retaining 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, In the circumferential direction, a pair of joint plates are arranged at both ends of the pair of main girders and constitute a part of the end face of the segment, In the radial direction of the cylindrical body, it is joined to the outer circumference of the pair of main girders, and the skin plate that constitutes the outer surface of the cylindrical body, Concrete is filled into the frame structure, which is composed of the pair of main girders, the pair of joint plates, and the skin plate. Equipped with, Of the pair of joint plates, at least one of the joint plates is It is formed integrally with the skin plate and is bent relative to the skin plate to form a part of the end face of the segment in the circumferential direction. The end faces of the segment in the circumferential direction are A segment having an end face portion in the central radial portion of the cylindrical body where the concrete is exposed.

2. Of the pair of joint plates, one of the joint plates is It is formed integrally with the skin plate, and at one end of the skin plate in the circumferential direction, it is bent relative to the skin plate to form a part of one end face of the segment in the circumferential direction. Of the pair of joint plates, the other joint plate is The segment according to claim 1, which is fixed to the other end of the skin plate in the circumferential direction by welding and constitutes a part of the other end face of the segment in the circumferential direction.

3. Each of the pair of joint plates is The segment according to claim 1, which is formed integrally with the skin plate and is bent relative to the skin plate at both ends of the skin plate in the circumferential direction to constitute a part of the end face of the segment in the circumferential direction.

4. In the circumferential direction, the pair of main girders are arranged at both ends and further comprise a pair of inner circumferential joint plates that form part of the end face of the segment. The pair of inner circumferential joint plates are, In the radial direction, it is arranged with a gap between it and the pair of joint plates. The two end faces of the aforementioned segment are The segment according to any one of claims 1 to 3, having the end face portion in which the concrete is exposed between the pair of joint plates and the pair of inner circumferential joint plates in the radial direction.

5. The pair of joint plates mentioned above include: A seal groove extending in the axial direction is formed therein. The aforementioned seal groove is The segment according to any one of claims 1 to 3, wherein the groove is recessed inward from the end face of the segment in the circumferential direction, and the groove is in which a waterproof sealing member is arranged.

6. The pair of inner circumferential joint plates include: An inner circumferential sealing groove extending in the axial direction is formed therein. The inner circumferential sealing groove is The segment according to claim 4, wherein the groove is recessed inward from the end face of the segment in the circumferential direction, and the groove is a groove in which a waterproof inner circumferential sealing member is arranged.

7. The end face portion has, A segment according to any one of claims 1 to 3, which is provided with a joint portion used as a joint for connecting adjacent segments in the circumferential direction.

8. A retaining structure formed by combining a plurality of segments according to any one of claims 1 to 3 in the circumferential direction and the axial direction.

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