JP7129848B2 - SEGMENT ASSEMBLY JIG AND SEGMENT MANUFACTURING METHOD - Google Patents

Description

The present invention relates to a segment assembly jig used in segment assembly and a segment manufacturing method using the segment assembly jig.

Shield construction methods, TBM construction methods, and the like are known as construction methods for constructing conventional tunnels. In the method of constructing these tunnels, the tunnel lining is formed by connecting tubular segment rings into the ground while excavating the ground. A segment ring is formed by connecting joint plates positioned on the end faces of a plurality of segments.

The segment is arc-shaped when viewed from the direction along which the tunnel extends. Each segment has a pair of longitudinal arc-shaped main girders, joint plates attached to both longitudinal end faces of the pair of main girders, and skin plates attached to the outer peripheral surfaces of the arc-shaped main girders. A segment is a housing formed by joining two main girders and two joint plates to form a frame, and joining a skin plate to the frame (see, for example, Patent Document 1). .

JP 2017-210769 A

The segments disclosed in Patent Document 1 are connected to the inside of the excavated ground to form the lining of the tunnel. need to be higher. However, the segments are manufactured by assembling steel plates by welding, and when joint plates and skin plates are welded to the main girders, they warp and deform toward the welding side, making it impossible to maintain the dimensional accuracy between the pair of main girders. There was a problem. In particular, the segment disclosed in Patent Document 1 further has a shape-retaining material arranged inside the housing, and is welded across a pair of main girders, so there are many welding points, It has become difficult to maintain high dimensional accuracy after welding.

SUMMARY OF THE INVENTION An object of the present invention is to provide a jig for segment assembly and a method for manufacturing a segment that can maintain high dimensional accuracy of the segment.

A segment assembly jig according to the present invention is used as a tunnel lining by joining a plurality of segments , and includes a pair of main girders formed in an arc shape along the circumferential direction of a cross section perpendicular to the direction in which the tunnel extends, and the A member including a pair of joint plates fixed to both ends of a pair of main girders in the circumferential direction, and a skin plate fixed to the arc-shaped outer peripheral side of the pair of main girders, and the members are assembled into a box shape. A jig for assembling a segment used for welding the members of the segment formed by the above, comprising: a jig bottom on which the plate surface of the skin plate is placed in contact; and an upper surface of the jig bottom a pair of jig side plates that are arranged facing each other in the upper side and support the plate surfaces of the pair of main girders in a state of facing each other , wherein each of the pair of jig side plates: A main girder abutting portion is provided on a surface facing the other jig side plate, and the main girder abutting portion abuts on the end main girder disposed at both ends in the longitudinal direction of each of the pair of jig side plates. and a center main girder abutting portion disposed between the end main girder abutting portions, wherein the end main girder abutting portions are arranged to face the pair of main girder abutting portions. The distance between the abutment surfaces with which the girders abut is constant from the jig bottom side to the tip of the side away from the jig bottom, and the central main girder abutment portions are arranged to face each other. In addition, the distance between the upper end portions of the contact surfaces with which the pair of main girders abut is larger than the distance between the lower end portions, and the plate surfaces of the pair of main girders are the plate surfaces of the pair of jig side plates. It is held in a state of being pressed against the respective end main girder abutment portions and the center main girder abutment portions .

A method for manufacturing a segment according to the present invention is a method for manufacturing a segment that is used as a tunnel lining by joining a plurality of segments, and the segment is formed in an arc shape along the circumferential direction of the cross section perpendicular to the direction in which the tunnel extends. A pair of main girders, a pair of joint plates fixed to both ends of the pair of main girders, and members including skin plates fixed to the arc-shaped outer peripheral sides of the pair of main girders are combined in a box shape and mutually a temporary assembly step of temporarily fixing; and a welding step of welding adjacent portions of the pair of main girders, the pair of joint plates, and the skin plates after the temporary assembly step, wherein the temporary assembly step is a placing step of placing at least the skin plate, the pair of main girders, and the pair of joint plates on the upper surface of a jig bottom plate forming the bottom of the segment assembly jig; a pressing step of pressing each of the pair of main girders against each of a pair of jig side plates arranged facing each other laterally above the upper surface; the skin plate, the pair of main girders, and the pair of joint plates; and a provisional welding step of partially welding portions close to each other , wherein each of the pair of jig side plates has a main girder contact portion on a surface facing the other jig side plate, and the main girder The abutting portions include end main girder abutting portions disposed at both longitudinal ends of the pair of jig side plates, and central main girder disposed between the end main girder abutting portions. The end main girder abutting part has a gap between the abutting surfaces with which the pair of main girders arranged facing each other abut so that the distance between the abutting surfaces is such that the distance between the abutting surfaces is such that the distance from the jig bottom side to the jig bottom side. The central main girder abutting portion has a constant distance between the tips of the abutting surfaces on which the pair of main girders arranged facing each other abut. The gap between the bottom sides of the jig is set to be larger than the distance between the bottom sides of the jig, and the pressing step includes bringing the pair of main girders into contact with the end main girder contact portion and the center main girder contact portion. and hold it .

According to the present invention, with the above configuration, the main girder can be stably brought into contact with the jig for assembling the segments, and welding can be performed in that state. As well as improving, manufacturing accuracy is improved. As a result, it is possible to improve the efficiency of the welding work and the quality of the product when manufacturing the segment.

FIG. 4 is a perspective view showing an example of a segment assembled using the segment assembly jig according to Embodiment 1; Figure 2 is a plan view of the main girder of the segment of Figure 1; FIG. 3 is a cross-sectional view showing a main girder that is a modification of the main girder of the segment of FIG. 1; FIG. 4 is a top view showing a state in which the members forming the segment are installed on the segment assembly jig and temporarily fixed; FIG. 5 is a schematic diagram of a cross-sectional structure taken along line AA of FIG. 4; FIG. 5 is a schematic diagram of the BB section of FIG. 4; FIG. 4 is a schematic diagram showing a state in which temporary assembly is being performed in the segment assembly jig according to Embodiment 1; FIG. 8 is a side view of the segment assembly jig of FIG. 7;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited by the embodiments described below. Each figure is shown schematically, and the relative size, plate thickness, etc. of each member are not limited to the dimensions shown in the figure. Also, in the following drawings, the size relationship of each component may differ from the actual size. In addition, in the figures, when no suffix (a, b, etc.) is attached to each part, the suffixed symbols are collectively referred to.

Embodiment 1.
FIG. 1 is a perspective view showing an example of a segment 1 assembled using a segment assembly jig 100 according to Embodiment 1. FIG. As shown in FIG. 1, the segment 1 is a box-shaped structure constructed by combining a plurality of steel materials, and the box-shaped bottom is curved in an arc shape. The segment 1 is used for lining a tunnel, for example, and is installed on the wall surface of an excavation hole formed by excavating the natural ground. A plurality of segments 1 are connected in the circumferential direction along the wall surface of the borehole to form a tubular segment ring. The axial sequential joining of the segment rings forms the tunnel lining. The inside of the box-shaped structure of the segment 1 is filled with, for example, concrete to constitute the wall surface inside the tunnel.

The segment 1 includes a pair of main girders 4 , a pair of joint plates 5 , a skin plate 6 and a plurality of longitudinal ribs 9 .

FIG. 2 is a plan view of main girder 4 of segment 1 of FIG. A pair of main girders 4 are positioned at both ends of the segment 1 in the tunnel axial direction. The main girder 4 is arc-shaped according to the cross-sectional shape of the tunnel. The main girder 4 is a plate-like member, and outer edges 43a and 43b, which are ridgelines along the longitudinal direction, are formed in circular arcs in plan view. The outer edge 43a of the main girder 4 located on the ground side is formed in an arc shape corresponding to the cross-sectional shape of the tunnel, and the outer edge 43b of the main girder 4 located inside the tunnel is formed in an arc shape concentric with the outer edge 43a. there is

A pair of joint plates 5 are members attached to both ends of the segment 1 in the tunnel circumferential direction. The joint plate 5 is made of a rectangular steel plate, spanned between both ends of the pair of main girders 4 in the longitudinal direction, and is fixed. A joint may be attached to the end of the segment 1 where the joint plate 5 is located to connect with the segment 1 forming one segment ring.

The skin plate 6 is a plate-like member facing the ground side of the segment 1, and is formed by bending a rectangular steel plate into an arc shape in the surface direction. As shown in FIG. 1, it is joined so as to close the opening of the end face of the frame 10 obtained by joining the pair of main girder 4 and joint plate 5 on the ground side. That is, the skin plate 6 is attached to the outer peripheral sides of the main girder 4 and the joint plate 5 that constitute the segment 1 .

Vertical ribs 9 are erected inside the box-shaped segment 1 . The vertical ribs 9 are erected in the direction normal to the surfaces of the main girder 4 and the skin plate 6 , and the ends of the vertical ribs 9 in the tunnel axial direction are joined to the surface 44 of the main girder 4 .

<Manufacturing Method of Segment 1>
Assembly of segment 1 will be described. A pair of main girders 4, joint plates 5, and skin plates 6 are temporarily fixed to each other (STEP 1). This process is called a temporary assembly process. The temporary assembly process is performed with the main girder 4 , the joint plate 5 and the skin plate 6 placed on the segment assembly jig 100 . In the temporary assembly process, the process of placing at least the skin plate 6, the main girder 4, and the joint plate 5 on the upper surface of the jig bottom portion 51 is particularly called a placing process. That is, the placing process is included in the temporary assembly process. Note that the vertical ribs 9 may be temporarily fixed in the temporary assembly process. Temporary fixation between each member is performed by spot welding, for example. By partially welding the members together, it is possible to secure the required assembly accuracy in the subsequent welding process while reducing the time required for the temporary assembly process. In the welding process, deformation of each member occurs due to welding, so temporary assembly is performed aiming at dimensions that take into account the deformation. The process of partially welding the skin plate 6, the main girder 4, and the joint plate 5 in close proximity to each other is called a temporary welding process. The temporary welding process is also included in the temporary assembly process.

After that, the temporarily assembled segment 1a is welded between members constituting the segment 1 (STEP 2). This process is called a welding process. In the welding process, the members constituting the temporarily assembled segment 1 are fixed together by welding, and the structure of the segment 1 is completed. In the welding process, the portions where the members forming the segment 1 are adjacent to each other are welded. Also, in the welding process, the entire portions where the members are close to each other are welded to ensure the joint strength between the members. The welding process is desirably performed by automatic welding by a robot in order to increase assembly efficiency. In addition, manual welding may be performed as appropriate for portions that are difficult to weld by a robot.

The structure of the segment 1 is completed by the above steps. After the structure of the segment 1 is completed, processes such as painting are performed as appropriate, and the segment is installed in the tunnel.

<Modified example of main girder 4>
FIG. 3 is a sectional view showing a main girder 4a which is a modification of the main girder 4 of the segment 1 of FIG. In Embodiment 1, the main girder 4 is a plate-shaped steel material, but the main girder 4a, which is a modified example, uses a plate-shaped steel material as a web 41, and a flange 42 is joined to the end of the web 41. You can That is, the main girder 4a of the modified example has a U-shaped cross section. As shown in FIG. 3, the web 41 is a plate-like steel material, has an arc-shaped outer edge 43a along the longitudinal direction, and has a linear edge in the longitudinal direction. An outer edge 43a of the web 41 located on the natural ground side has an arc corresponding to the cross-sectional shape of the tunnel. An outer edge 43b of the web 41 located inside the tunnel is concentric with the outer edge 43a located on the ground side and has a small diameter arc. An outer flange 42a of the flange 42 is a plate-shaped steel material, and is bent in the planar direction to match the outer edge 43a on the ground side. The inner flange 42b is also a plate-like steel material, and is bent in the planar direction to match the outer edge 43b inside the tunnel. Web 41 and flange 42 are joined by welding. The main girder 4a is not limited to being assembled by welding as described above, and may be a member in which the web 41 and the flange 42 are integrally formed.

<Details of the temporary assembly process>
FIG. 4 is a top view showing a state in which the members constituting the segment 1 are installed on the segment assembly jig 100 and temporarily fixed. FIG. 4 shows only the main girder 4, the joint plate 5, and the skin plate 6 among the members constituting the segment 1. FIG. If the segment 1 has longitudinal ribs 9 as a structure, it may be arranged between a pair of main girders 4 in the state shown in FIG.

<Structure of segment assembly jig 100>
FIG. 5 is a schematic diagram of a cross-sectional structure taken along line AA of FIG. FIG. 6 is a schematic diagram of the BB section of FIG. 4, 5, and 6 show the state before the temporary welding process, in which the placing process of placing at least the skin plate 6, the main girder 4, and the joint plate 5 on the upper surface of the jig bottom 51 is completed. showing. A jig bottom portion 51 is arranged at the bottom portion of the segment assembly jig 100 . A member forming the segment 1 is placed on the jig bottom portion 51 . A pair of jig side plates 52 are arranged facing each other at a predetermined distance above the top surface of the jig bottom portion 51 . Although the jig side plate 52 is placed on the jig bottom portion 51 in FIGS. 5 and 6, it is not limited to this form. For example, the jig bottom portion 51 and the jig side plate 52 may be separately fixed on the floor.

As shown in FIGS. 4 and 5, the jig side plate 52 has a main girder contact portion 53 on the surface facing the other jig side plate 52 . A main girder contact portion 53 positioned at an end portion in the longitudinal direction of the jig side plate 52 has a contact surface 53a formed vertically. That is, the distance between the two opposing contact surfaces 53a is configured to be constant from the jig bottom portion 51 side to the upper end of the jig side plate 52 .

As shown in FIGS. 4 and 6, the jig side plate 52 has a main girder contact portion 54 on the surface facing the other jig side plate 52 . A contact surface 54a of the main girder contact portion 54 located at the central portion in the longitudinal direction of the jig side plate 52 is inclined. The contact surface 54a is inclined in a direction away from the other jig side plate 52 as it goes upward from the jig bottom portion 51 side. In other words, the contact surfaces 54a provided on the pair of jig side plates 52 are formed such that the distance between one contact surface 54a and the other contact surface 54a increases upward. That is, in the pair of jig side plates 52, the distance between the upper end portions of the contact surfaces 54a is greater than the distance between the lower end portions of the contact surfaces 54a. In addition, in FIG. 6, the inclination of the contact surface 54a is exaggerated.

As shown in FIG. 4, main girder contact portions 53 are arranged at two locations on both ends in the longitudinal direction of the jig side plate 52, and a main girder contact portion 54 is arranged at one location in the central portion. It is In the jig side plate 52, between the main girder contact portion 53 at the end portion and the main girder contact portion 54 at the central portion, a concave surface is formed with respect to the contact surfaces 53a and 54a. . Therefore, the main girder 4 placed on the segment assembly jig 100 contacts the jig side plate 52 only at the contact surfaces 53a and 54a.

FIG. 7 is a schematic diagram showing a state in which temporary assembly is being performed in the segment assembly jig 100 according to the first embodiment. FIG. 8 is a side view of the segment assembly jig 100 of FIG. FIG. 7 shows the same cross-section as FIG. 6, with vise members 61 and 62 added to FIG. The white arrows shown in FIGS. 4 to 6 indicate positions where loads are applied by the vise members 61 and 62. As shown in FIG. That is, the vise members 61 and 62 are installed so that the load is applied from the vise members 61 and 62 to the portions indicated by the white arrows.

In the segment 1 temporary assembly process, the vise members 61 and 62 are installed so as to straddle the jig side plate 52 and the main girder 4 installed in the segment assembly jig 100 . One vise member 61 is smaller than the other vise member 62 and abuts on the upper end portion of the main girder 4 which is the portion of the main girder 4 closer to the inner side of the tunnel. The larger vise member 62 abuts on the lower end portion of the main girder 4, which is the portion of the main girder 4 closer to the ground.

A main girder side contact surface 64 of the vise member 61 abuts on a portion of the main girder 4 closer to the inner side of the tunnel. A jack-side contact surface 63 of the vise member 61 contacts a hydraulic jack 56 fixed to the outer surface of the jig side plate 52 . In addition, the main girder side contact surface 66 of the vise member 62 contacts the portion of the main girder 4 closer to the ground, and applies a load so as to press the main girder 4 against the contact surface 54a. A jack-side contact surface 65 of the vise member 62 is in contact with a hydraulic jack 56 fixed to the surface of the jig side plate 52 facing outward. Hydraulic jack 56 operates in the direction of arrow C in FIG. That is, the vise members 61 and 62 apply a load so as to press the main girder 4 against the contact surface 54a. Although the hydraulic jack 56 is fixed to the surface of the jig side plate 52 opposite to the surface facing the other jig side plate 52, it may be fixed to the vise members 61 and 62 side. Further, the hydraulic jack 56 may use other load generating means as long as the load can be applied between the segment assembly jig 100 and the vise members 61 and 62 .

FIG. 7 shows a state in which temporary assembly is being performed on the BB cross section of FIG. is pressed against the contact surface 53 a of the main girder contact portion 53 . This process of pressing the main girder 4 against the jig side plate 52 is called a pressing process. The pressing process is included in the temporary assembly process.

In Embodiment 1, the vise members 61 and 62 are separate from the jig side plate 52 and are detachable from the jig side plate 52. It is configured. With this configuration, there is an advantage that the vise members 61 and 62 can be used in common in a plurality of segment assembly jigs 100 . However, other means may be used as long as the main girder 4 can be pressed toward the segment assembly jig 100 .

The segment assembling jig 100 is provided with a vise positioning member 55 at the upper end portion of the jig side plate 52 . The vise members 61 , 62 are aligned with the vise positioning member 55 to constrain the longitudinal position of the segment 1 a during assembly and are also aligned with the hydraulic jack 56 .

As shown in FIGS. 4-7, the main girder 4 lies inside the tunnel of the main girder 4 at the longitudinal center with the surface 44 vertical at both longitudinal ends. It is fixed to the segment assembling jig 100 so that the outer edge 43b opens outward from the outer edge 43a located on the ground side. In this state, the main girder 4, the joint plate 5, and the skin plate 6 are temporarily welded together. Temporary welding is performed by spot-welding portions of adjacent portions of each member. Moreover, when the segment 1 is provided with other members, for example, the longitudinal ribs 9 as a structure, they may be temporarily welded.

In the temporary assembly process, the segment 1a is temporarily assembled to dimensions that allow for deformation in the subsequent welding process. Specifically, the outer edges 43b of the pair of main girders 4 positioned inside the tunnel at the central portion are deformed so as to come closer to each other in the welding process. The distance between the outer edges 43b positioned inside the tunnel at the central portion of the main girder 4 in the temporary assembly process is determined according to the shape of the main girder contact portion 54. As shown in FIG. Therefore, by changing the main girder abutting portion 54, the distance between the inner ends of the tunnel at the central portion of the main girder 4 can be appropriately adjusted.

In the temporary assembly process, the hydraulic jack 56 presses the main girder 4 forming the segment 1 a against the main girder contact portions 53 and 54 provided on the jig side plate 52 . With this configuration, the main girder 4 is reliably fixed to the jig side plate 52 along the main girder abutment portions 53 and 54, so that the dimensional accuracy of the segment 1a during temporary assembly is stabilized. Further, since the rigidity of the main girder 4 is high, the load generating means must generate a large load. In this regard, the hydraulic jack 56 can generate a large load with a simple structure, and is more durable than, for example, a jack mechanism using screws.

<Welding process>
After the temporary assembly process, the segments 1a are welded together in the welding process. The parts where the respective members are close to each other are integrated by welding the entire area of the parts close to each other by, for example, robot welding. Each member tends to be warped and deformed by welding so as to be pulled toward the welded portion. In particular, since the pair of main girders 4 are welded from the inside of the box-shaped segment 1, the ends of the inside of the tunnel at the center in the longitudinal direction are deformed toward each other. In the first embodiment, since the position of the inner end of the tunnel at the center of the longitudinal direction of the main girder 4 is adjusted and temporarily fixed in the temporary assembly process, even if the segment 1 is deformed in the welding process, The required accuracy can be secured.

1 segment, 1a segment, 4 main girder, 5 joint plate, 6 skin plate, 9 longitudinal rib, 10 frame, 11 joint, 12 joint, 41 web, 42 flange, 42a outer flange, 42b inner flange, 43 outer edge, 43a outer edge 43b outer edge 44 surface 51 jig bottom plate 52 jig side plate 53 main girder contact portion 53a contact surface 54 main girder contact portion 54a contact surface 55 vise positioning member 56 hydraulic pressure Jack, 61 Vise, 62 Vise, 63 Jack-side contact surface, 64 Main girder-side contact surface, 65 Jack-side contact surface, 66 Main girder-side contact surface, 91 Hanging reinforcing bar, 92 Rod-shaped reinforcing member, 100 Segment assembly jig, C arrow.

Claims (6)

A pair of main girders that are joined together and used as a tunnel lining and formed in an arc shape along the circumferential direction of a cross section perpendicular to the direction in which the tunnel extends, and at both ends of the pair of main girders in the circumferential direction Welding of the members of a segment formed by combining a pair of joint plates fixed to each other and a skin plate fixed to the outer peripheral side of the arc shape of the pair of main girders, and combining the members into a box shape. A segment assembly jig used for
a jig bottom portion placed in a state where the plate surface of the skin plate is in contact;
a pair of jig side plates arranged above the upper surface of the jig bottom to face each other and supporting the plate surfaces of the pair of main girders in a state of facing each other;
Each of the pair of jig side plates,
Equipped with a main girder contact portion on the surface facing the other jig side plate,
The main girder contact portion is
end main girder abutting portions arranged at both ends in the longitudinal direction of each of the pair of jig side plates;
and a center main girder contact portion disposed between the end main girder contact portions,
The end main girder contact portion is
The distance between the abutment surfaces with which the pair of main girders arranged facing each other abut is constant from the bottom side of the jig to the tip of the side away from the bottom portion of the jig,
The central main girder contact portion is
the interval between the upper end portions of the contact surfaces with which the pair of main girders arranged facing each other are in contact with each other is larger than the interval between the lower end portions;
Each of the pair of main girders,
A jig for assembling segments , wherein the plate surface is held in a state of being pressed against the end main girder contact portion and the center main girder contact portion of the pair of jig side plates . Each of the pair of jig side plates,
A load generating means is installed on the outer surface located on the opposite side of the surface facing the other jig side plate,
The load generating means is
2. The segment assembly jig according to claim 1, wherein a load is generated in a direction to press each of said pair of main girders against said main girder contact portion. further comprising a vise member that contacts one of the load generating means and one of the pair of main girders ,
The load generating means is
positioned between one end of the vise member and the outer surface to load the one end of the vise member outwardly;
The vise member is
When the load generating means applies a load to one end of the vise member straddling one jig side plate of the pair of jig side plates and the main girder, the other end of the vise member arranged so as to press the girder against the main girder contact portion,
The jig side plate is
3. The segment assembling jig according to claim 2, further comprising a vise positioning member provided at an upper end portion thereof for regulating the position of said vise member in the longitudinal direction of said jig side plate . A method for manufacturing a segment that is used as a tunnel lining by joining a plurality of segments,
A pair of main girders formed in an arc shape along the circumferential direction of a cross section perpendicular to the direction in which the tunnel extends, a pair of joint plates fixed to both ends of the pair of main girders, and the pair of main girders. a temporary assembly step of combining members including a skin plate fixed to the outer peripheral side of the arc shape into a box shape and temporarily fixing them to each other;
a welding step of welding adjacent portions of the pair of main girders, the pair of joint plates, and the skin plates after the temporary assembly step;
The temporary assembly process includes:
a placing step of placing at least the skin plate, the pair of main girders, and the pair of joint plates on the upper surface of a jig bottom plate forming the bottom of the segment assembly jig;
a pressing step of pressing each of the pair of main girders against each of a pair of jig side plates arranged facing each other laterally above the upper surface of the jig bottom plate;
a temporary welding step of partially welding portions of the skin plate, the pair of main girders, and the pair of joint plates that are close to each other ;
Each of the pair of jig side plates,
Equipped with a main girder contact portion on the surface facing the other jig side plate,
The main girder contact portion is
end main girder abutting portions arranged at both ends in the longitudinal direction of each of the pair of jig side plates;
and a center main girder contact portion disposed between the end main girder contact portions,
The end main girder contact portion is
The distance between the abutment surfaces with which the pair of main girders arranged facing each other abut is constant from the bottom side of the jig to the tip of the side away from the bottom portion of the jig,
The central main girder contact portion is
The distance between the tips of the contact surfaces with which the pair of main girders arranged facing each other are in contact is configured to be larger than the distance between the bottom sides of the jig,
The pressing step includes:
A method of manufacturing a segment, wherein the pair of main girders are held in contact with the end main girder contact portion and the center main girder contact portion . The segment assembly jig is
load generating means for generating a load on the side that presses each of the pair of main girders against each of the pair of jig side plates,
The pressing step includes:
activating the load generating means to apply a load to the tunnel inner end portion and the ground side end portion of each of the pair of main girders;
5. The method of manufacturing a segment according to claim 4, wherein said temporary welding step is performed during said pressing step. The segment assembly jig is
a vise member that contacts one of the pair of main girders and the load generating means;
The vise member is
contacting the main girder and the load generating means across one jig side plate of the pair of jig side plates;
The pressing step includes:
6. The method of manufacturing a segment according to claim 5, wherein a load is applied from said load generating means to said vise member and a load is applied from said vise member to said main girder.

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