segment

Abstract

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

Description

Technical Field

[0001] The present invention relates to segments used in the shield method, the propulsion method, the non-excavation tunnel method, and the urban ring method (segmental retaining wall method).

Background Art

[0002] Segments are roughly divided into concrete segments and steel segments. The former concrete segments are strong in compression, and the latter steel segments are strong in tension. On the other hand, by integrating such concrete and steel segments, composite segments having characteristics combining these advantages are used.

[0003] As such a composite segment, for example, a frame body 2 composed of steel plates, main reinforcing bars (main steel materials) 8 and distribution bars 20 arranged in the frame body 2, and concrete 3 placed so as to bury the main reinforcing bars 8 and distribution bars 20 inside the frame body 2 (see FIGS. 1 and 2) are known (see Patent Document 1).

[0004] Also, a pair of main girders 12, 12 extending in the tunnel circumferential direction and located at the portal side end face and the face side end face of the composite segment 11, joint plates 13, 13 extending in the tunnel axis direction and provided with segment joints, and these main girders 12, 12 and joint plates 13, 13 A steel shell is constituted by a ground side steel plate 14a provided on the ground side and an inner space side steel plate 14b provided on the inner space side of the tunnel, and concrete 17 is filled in the inside thereof. A large number of stud dribs 16a, 16b for enhancing the integrality with the filled concrete are welded and implanted on the inner surfaces of the ground side steel plate 14a and the empty side steel plate 14b (see Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] By the way, in the segment described in Patent Document 1, the frame and concrete are integrated by pouring concrete so that the main reinforcement and distribution reinforcement inside the frame are embedded, while in the segment described in Patent Document 2, stud dowels are embedded in the frame (steel shell), and the frame (steel shell) and concrete are integrated by the stud dowels. In other words, these segments are designed by integrating the frame (steel shell) and concrete into a single structure.

[0007] On the other hand, if complex-shaped accessories such as main reinforcement bars, distribution bars, and stud dowels are not installed inside the frame, and the frame and the concrete inside the frame are not integrated, it becomes possible to design them separately. However, separating the frame from the concrete has the disadvantage that it makes it easier for misalignment to occur between the two. Furthermore, if a displacement occurs between the frame and the concrete, the rigidity and load-bearing capacity of the segment may decrease.

[0008] This invention has been made in view of the above circumstances, and aims to provide a segment that can be designed separately and that can suppress displacement between the frame and the concrete. [Means for solving the problem]

[0009] The inventors of the present invention, in order to solve the above problems, found that by not integrating the frame and the concrete, thereby separating the design of the concrete and the design of the frame, and further by creating a configuration in which a part of the concrete is directly restrained by a part of the frame, that is, a configuration in which the concrete is restrained by the frame even when it tries to deform due to stress-induced strain, the above problems can be solved, and thus the present invention was completed.

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

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

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

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

[0014] In the segment of the present invention, it is preferable that the bottom plate is provided with a plurality of air vents.

[0015] In the segment of the present invention, it is preferable that an injection hole or a gripping hole extending inward from the top of the protruding portion is provided in the concrete. [Effects of the Invention]

[0016] The segment of this invention makes it possible to separate the design of the concrete from the design of the frame by keeping the frame and concrete disconnected and not integrating them. The design of the segment as a whole is a combination of these two elements. In this case, the influence of voids within the concrete and the shrinkage of the concrete itself on the frame can be eliminated, thus simplifying the design. Furthermore, it allows for increased design flexibility in the frame and concrete structure. Furthermore, since the frame and concrete are separate components, there is no need to provide complex-shaped accessories for integration inside the frame. For this reason, the segment of the present invention is also superior in terms of manufacturability and cost-effectiveness.

[0017] In the segment of the present invention, the concrete protrusion is secured from both sides by the central end on the opening side of the bottom plate of the frame, thereby suppressing axial displacement between the frame and the concrete. Furthermore, displacement in the circumferential direction can be made difficult by friction between the central end and the protrusion.

[0018] In the segment of the present invention, concrete can be efficiently poured into the hollow section by utilizing the opening provided in the bottom plate. In this case, by extending the opening from one joint plate to the other, concrete pouring can be carried out quickly. In other words, the working time can be significantly reduced. In addition, after assembling the frame body, so-called on-site casting of concrete becomes easy at the site, and thus the assembly cost and transportation cost of the segments can be significantly reduced.

[0019] In the segment of the present invention, by providing the opening at the center in the axial direction of the bottom plate, the concrete before hardening can be evenly introduced into both main girder plate sides of the hollow part. That is, since the concrete before hardening does not overly deviate, it becomes possible to smoothly place the concrete. In addition, by setting the size of the opening in the axial direction within the above range, it is easy to place the concrete, and the bottom plate can also exhibit sufficient strength.

[0020] In the segment of the present invention, by providing a connecting portion linked between the central side end portion on one side and the central side end portion on the other side, it becomes possible to make the bottom plate on one side and the bottom plate on the other side cooperate to exert stress. Thereby, it can sufficiently resist the acting load. Moreover, since the protruding portion of the concrete is configured to be restrained by adjacent connecting portions, it is possible to further suppress the occurrence of circumferential displacement between the frame body and the concrete. That is, the restraint of the concrete can be made more reliable. At this time, by adopting steel materials or reinforcing bars as the connecting portion, sufficient strength can be exerted.

[0021] Also, when the connecting portion is a steel material, by making the end portions on both sides of the connecting portion be beveled portions for opening and welding the connecting portion, the bottom plate on one side, and the bottom plate on the other side at a certain route interval, even in the case of post-attaching to the frame body, the connecting portion can be attached to the frame body with high strength.

[0022] In the segment of the present invention, by providing a plurality of air vent holes, the inflow of the concrete can be performed promptly, and it is also possible to confirm the filling of the concrete.

[0023] In the segment of the present invention, so-called injection holes or gripping holes are directly provided in the concrete, so these can be easily formed by setting up formwork when pouring the concrete. [Brief explanation of the drawing]

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

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

[0026] The segment according to the present invention can be used, for example, as a piece for constructing a cylindrical shield wall in a tunnel. In this case, the segments are connected to each other by joint plates in the circumferential direction of the shield cylindrical wall, and by main girder plates in the axial direction of the shield cylindrical wall. The shield cylindrical wall is formed by repeating this process.

[0027] Herein, in this specification, "circumferential direction" means the longitudinal direction of the segment (circumferential direction of the shield cylindrical wall), "axial direction" means the width direction of the outer and bottom plates of the segment (axial direction of the shield cylindrical wall), and "internal-external direction" means the thickness direction of the segment. Furthermore, "inside" refers to the hollow side of the tunnel in relation to the segments, while "outside" refers to the opposite side. Furthermore, "acting load" refers to loads that include not only the "vertical and horizontal earth pressure," "water pressure," "ground reaction force," and "self-weight of the lining" that are constantly acting, but also "superfluous loads," "construction loads," and "earthquake loads."

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

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

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

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

[0032] The outer plate 12 is an arch-shaped plate that curves along the outer edge of the main girder plate 11. In segment 100, the ends of the outer plate 12 on the main girder plate 11 side are welded to the outer ends of the main girder plate 11. Details of this welding will be described later. As a result, the outer plate 12 is positioned on the ground side of the shield cylindrical wall. The dimensions of the outer plate 12, such as its width (axial length), thickness (internal-external length), and curvature (degree of curve), can be appropriately set according to the size of the shield cylindrical wall.

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

[0034] In segment 100, the bottom plate 13 is provided with an opening 16 that extends circumferentially from one joint plate 14 to the other joint plate 14. That is, the bottom plate 13 is divided by the opening 16 into one bottom plate (hereinafter also referred to as the "first bottom plate 13a" for convenience) and the other bottom plate (hereinafter also referred to as the "second bottom plate 13b" for convenience). The width (axial length), thickness (internal / external length), curvature (degree of curve), and other dimensions of the first bottom plate 13a and the second bottom plate 13b can be appropriately set according to the size of the shield cylindrical wall.

[0035] As described above, the bottom plate 13 is provided with an opening 16, and by utilizing this opening 16, it becomes possible to efficiently pour concrete into the hollow section. Furthermore, since the opening 16 extends from one joint plate 14 to the other joint plate 14, concrete can be poured quickly and efficiently. Furthermore, so-called on-site casting becomes easier. In this case, the assembly and transportation costs of segment 100 can be significantly reduced.

[0036] Here, it is preferable that the axial length of the first bottom plate 13a and the axial length of the second bottom plate 13b are approximately the same. That is, it is preferable that the opening 16 is located in the center of the entire bottom plate 13 in the axial direction. In this case, it becomes possible to evenly distribute the concrete before hardening to both sides of the main girder plate 11 in the hollow section.

[0037] In the base plate 13, if the thickness (length in the inward / outward direction) of the first base plate 13a and the second base plate 13b is t, it is preferable that the width (length in the axial direction) of each of the first base plate 13a and the second base plate 13b be 25 × t or less. In this case, concrete pouring is easier, and the base plate can exhibit sufficient strength. Furthermore, in cases where the plate thickness is thin and the hollow portion becomes too wide relative to the segment width, the thickness may be increased to 25t to form only the necessary gaps.

[0038] Both the first bottom plate 13a and the second bottom plate 13b are provided with a number of air vents 17 at regular intervals at the end facing the main girder plate 11. Air escapes through the air vent holes 17, allowing for rapid concrete flow and also enabling confirmation of concrete filling through the air vent holes 17.

[0039] The opening 16 preferably has an axial size of 100 mm to 500 mm. If the size of the opening 16 is less than 100 mm, concrete pouring becomes more difficult compared to when the size of the opening 16 is within the above range, and the location of the injection holes or gripping holes described later becomes limited, and it may become difficult to provide them. On the other hand, if the size of the opening 16 exceeds 500 mm, the axial dimensions of the first bottom plate 13a and the second bottom plate 13b become smaller compared to when the size of the opening 16 is within the above range, which may result in insufficient strength of the bottom plate 13.

[0040] The connecting portion 15 is provided to connect the central end of the first bottom plate 13a on the opening 16 side and the central end of the second bottom plate 13b on the opening 16 side. From the viewpoint of strength, steel or reinforcing bars are preferably used for the connecting portion 15. In segment 100, a connecting portion 15 is provided to connect the first bottom plate 13a and the second bottom plate 13b, making it possible to coordinate the stress exerted by the first bottom plate 13a and the second bottom plate 13b. This allows for sufficient resistance to applied loads.

[0041] Furthermore, multiple connecting parts 15 are provided in the opening 16 at regular intervals. The width (circumferential length) of the connecting portion 15 and the circumferential distance between adjacent connecting portions 15 can be appropriately determined from the relationship between the segment width (axial length) and the thickness of the base plate. In this case, the strength of the first bottom plate 13a and the second bottom plate 13b can be improved by connecting them without hindering the injection of concrete into the hollow section or the formation of injection holes or gripping holes described later.

[0042] Figure 3 is a partial cross-sectional view illustrating the welding between the connecting portion and the bottom plate in the segment according to this embodiment. When the connecting portion 15 is a plate-shaped steel material, it is preferable that both ends 15a of the connecting portion 15 are groove-welded inclined portions, and that the connecting portion 15 and the first bottom plate 13a and the second bottom plate 13b are groove-welded at a certain root interval M. In this case, even when attaching to the frame 10 afterwards, by deliberately choosing groove welding during the welding process, the strength of the welded portion can be improved. Furthermore, in this case, from the viewpoint of further improving strength, the root spacing M is preferably 1 to 3 mm, and the inclination angle θ of the beveling inclined portion is preferably 30 to 50°.

[0043] On the other hand, if the connecting portion 15 is made of reinforcing bars, it is preferable to provide them at regular intervals with a diameter of 16 mm or more. The diameter and quantity of reinforcing bars are determined by the width of the hollow section and the thickness of the base plate 13. Furthermore, the reinforcing bars can be welded to the first bottom plate 13a and the second bottom plate 13b on the inner side, for example, via welded joints.

[0044] Returning to Figure 1, the joint plates 14 are plates provided on both sides of the segment 100. The joint plates 14 on both sides are identical in shape. In the shield tunneling method, the joint plate 14 is connected to the joint plate of the adjacent segment by a known method. The joint plate 14 may also be processed on its front side for connection. This forms the circumferential shield cylindrical wall. The thickness (circumferential length) and other dimensions of the joint plate 14 can be appropriately set according to the size of the shield cylindrical wall.

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

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

[0047] Thus, in segment 100, by selecting groove welding among the various types of welding for each weld, the strength of the welded portion can be improved. Furthermore, the inclination angles of the first to fifth root spacing and the first to fifth groove inclined sections are the same as those of the root spacing and groove inclined sections in the welding between the connecting section and the base plate described above.

[0048] Returning to Figure 2, the concrete 20 is poured into the hollow portion of the frame 10. Here, the frame 10 and the concrete 20 are separate entities and are not connected or integrated. In other words, there are no complex accessories or anything that would be embedded in the concrete 20. This makes it possible to separate the design related to the concrete 20 from the design related to the frame 10. The design related to the segments will be a combination of these two.

[0049] As a result, the influence of voids within the concrete 20 and the shrinkage of the concrete 20 itself on the frame 10 can be eliminated, thus simplifying the design. Furthermore, it is possible to increase the design flexibility of the frame 10 and the concrete 20. Furthermore, since there is no need to provide complex-shaped accessories for integration inside the frame 10, it is also superior in terms of manufacturability and cost-effectiveness.

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

[0051] The main body 21 is not connected to the main girder plate 11, outer plate 12, and bottom plate 13 (first bottom plate 13a and second bottom plate 13b) of the frame 10. The protruding portion 22 is not connected to the base plate 13, but is secured from both sides by the central end of the first base plate 13a on the opening 16 side and the central end of the second base plate 13b on the opening 16 side. Furthermore, although the protruding portion 22 is not connected to the aforementioned connecting portion 15, it is restrained by adjacent connecting portions. These measures suppress axial and circumferential displacement between the frame 10 and the concrete 20. In other words, in segment 100, the frame 10 and the concrete 20 are not connected, and a protrusion 22 is provided on the concrete 20 to prevent the concrete 20 from shifting relative to the frame 10.

[0052] Next, we will describe the case where the segment is provided with a gripping hole 30 or an injection hole 31. Figure 6 is a cross-sectional view of the segment shown in Figure 1, cut along the YY line of the segment with a gripping hole. As shown in Figure 6, a cylindrical gripping hole 30 is provided in the center of the concrete 20. The gripping hole 30 is a hole used by the assembly device to grip the segment during assembly in the shield tunneling method. In segment 100, the frame 10 is not processed, and gripping holes 30 are provided only in the concrete 20. Therefore, the gripping holes 30 can be easily formed by setting up formwork or the like when pouring the concrete 20. Furthermore, gripping holes 30 can be added later to accommodate the assembly device.

[0053] Figure 7 is a cross-sectional view of the segment shown in Figure 1, cut along the YY line of the segment in which the injection hole is provided. As shown in Figure 7, the concrete 20 has a cylindrical injection hole 31 in the center that penetrates from the interior side to the ground side. The injection hole 31 is a hole for injecting backfill material. In some cases, the injection hole 31 also serves as a gripping hole for the assembly device to grip the segment during assembly. Such injection holes 31 can be easily formed when pouring concrete 20 by setting up formwork or the like. In this case, the outer panel 12 also needs to have holes at positions corresponding to the injection holes 31. In addition, in the segment 102 shown in Figure 8(b), which will be described later, an opening 26 is also provided in the outer plate 12, so it is not necessary to make a hole in the outer plate by utilizing this opening 26. In this case, the frame does not need to be processed, and the injection hole 31 can be formed using only the concrete 20.

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

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

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

[0057] In the segment 100 according to this embodiment, the bottom plate 13 is provided with an opening 16 that extends circumferentially from one joint plate 14 to the other joint plate 14. However, the opening 16 does not necessarily have to extend continuously and may be provided only partially. In this case, the shape of the opening, when viewed from the front, may be rectangular, elliptical, or the like.

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

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

[0060] In the segment 100 according to this embodiment, the opening 16 is provided only in the bottom plate 13, but the invention is not limited to this. Figure 8(b) is a cross-sectional view of another segment according to the second embodiment, cut in the width direction. Note that the cross-section shown in Figure 8(b) is at the same location as the cross-section cut along line XX in Figure 1. As shown in Figure 8(b), the segment 102 may also have an opening 26 in the outer panel 12a. Furthermore, it is preferable that the position and shape of the opening 26 in the outer plate 12a are the same as the opening 16 in the bottom plate 13 described above.

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

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

[0063] Figure 8(e) is a cross-sectional view of another segment according to the fifth embodiment, cut in the width direction. Note that the cross-section shown in Figure 8(e) is at the same location as the cross-section cut along line XX in Figure 1. As shown in Figure 8(e), segment 105 is provided with flanges 19a extending inward from the frame at the central ends of the first bottom plate portion 13a and the second bottom plate portion 13b of segment 102 according to another second embodiment, and flanges 19c extending inward from the frame are provided at the central end of one outer plate 12a and the central end of the other outer plate. As a result, the main body is partially connected to the frame via flanges 19a and 19c.

[0064] Although the segment 100 in this embodiment is generally arc-shaped, it may also be linear (rectangular). In this case, the opposing pair of main girder plates are rectangular in shape. Furthermore, the segments in this case can be used in tunnels with a rectangular cross-section (shield rectangular wall). Incidentally, in this case, "circumferential direction" refers to the longitudinal direction of the segment (the circumferential direction of the shielded rectangular wall). [Industrial applicability]

[0065] This invention is used as a segment for shield tunneling, pipe jacking, trenchless tunneling, and urban ring construction (partial assembly type earth retaining wall construction). For example, it can be used as a piece to construct a cylindrical shield wall in a tunnel. According to the segment of the present invention, separate design is possible, and displacement between the frame and the concrete can be suppressed. [Explanation of Symbols]

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

Claims

1. A segment used to construct a cylindrical shield wall in a tunnel, comprising a box-shaped frame having a hollow section and no accessories in the hollow section, and concrete cast into the hollow section, The frame comprises a pair of opposing main girder plates, outer plates welded to the outer ends of both main girder plates, bottom plates welded to the inner ends of both main girder plates, and joint plates welded to both ends of both main girder plates, the outer plates, and the bottom plates. The bottom plate is provided with an opening that extends in the circumferential direction from one joint plate to the other joint plate. When the bottom plate on one side separated by the aforementioned opening is designated as the first bottom plate, and the bottom plate on the other side is designated as the second bottom plate, The axial length of the first base plate and the axial length of the second base plate are the same. When the thickness of both the first and second base plates is denoted as t, the axial length of each of the first and second base plates is 25 × t or less. The axial size of the opening is 100 to 500 mm. The opening is provided with multiple connecting parts, each made of a plate-shaped steel material, at regular intervals, which are connected to the central end on one side of the bottom plate facing the opening and to the central end on the other side. Both ends of the connecting portion are grooved inclined portions, and the connecting portion and the bottom plate on one side and the bottom plate on the other side are grooved welded together at a certain root interval so that their surfaces are flush. The concrete is a convex body having a main body and a protruding portion provided on the main body. The aforementioned concrete is not connected to the frame. The protruding portion is secured from both sides by the central end of the bottom plate on the opening side, The aforementioned protruding portion is restrained from both sides by the adjacent connecting portions, A segment in which the top of the protruding portion is exposed from the opening.

2. The aforementioned root spacing is 1 to 3 mm. The segment according to claim 1, wherein the angle of inclination of the beveling inclined portion is 30 to 50°.

3. The outer plate, the main girder plate, and the joint plate are tack-welded and then groove-welded. The first bottom plate or the second bottom plate and the main girder plate and joint plate are tack-welded and then groove-welded. The segment according to claim 1, wherein the main girder plate and the joint plate are groove-welded after tack welding.

4. The segment according to claim 1, wherein the outer plate is provided with an outer plate opening extending in the circumferential direction.

5. The bottom plate is provided with multiple air vents. The segment according to claim 1, wherein an injection hole or a gripping hole extending inward from the top of the protruding portion is provided in the concrete.

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