JP7634841B2 - Apparatus and method for assembling lower half tunnel segments - Google Patents

Description

The present invention relates to a technique for constructing the lower lining wall of a tunnel with a widened excavation cross section constructed between two parallel tunnels, and relates to an assembly device and assembly method for the lower half segments of a tunnel. In particular, the present invention relates to a technique for assembling the lower half segments by moving multiple segment pieces that make up the segment to an assembly position when the segment that makes up the lower lining wall is constructed.

When constructing a road tunnel underground, for example, it is necessary to connect a ramp tunnel that branches off to or merges with an above-ground road to an underground main line tunnel. A method of constructing these joint areas underground involves constructing two tunnels side-by-side in close proximity, and then widening and excavating the ground between the linings of the two parallel tunnels to create an underground space. The present invention relates to an assembly device for the lower-half segments of this widening and excavation tunnel, and an assembly method using this assembly device.

The technology disclosed in Patent Document 1 has been proposed as a prior art for such construction. This technology involves assembling arch-shaped segments that are the upper lining wall of a widening excavation tunnel, and the curvature direction is opposite to that of the segment shape of the lower lining wall of the present invention, resulting in a different assembly workability. In addition, the arch-shaped segments were devised on the premise of using steel segments (box-shaped structure made of steel plates). However, in recent years, the cross-sectional shape of widening excavation tunnels has tended to become larger, and in order to accommodate construction conditions at great depths, heavy-structure segments (for example, segment pieces with a steel shell filled with concrete) are used for the lining structure. For this reason, the weight of each segment piece has become several times larger than before. In consideration of these conditions, it has become difficult to respond with the assembly equipment of the prior art, and improvements have become necessary.

JP 2014-211054 A

The technology in Patent Document 1 is implemented in the construction of a lining wall at the top of the widening excavation section between two parallel tunnels. Therefore, this technology in Patent Document 1 cannot be applied to the construction of a lower lining wall, which has a different curvature direction from the upper lining wall.

In the conventional method of assembling the segments that make up the lower lining wall of a widening excavation tunnel, the segments are made of steel and have a box shape. Because of this, they are relatively light and allow for flexibility in assembly work, and they are assembled on a temporary assembly platform using a temporary lifting machine such as a traveling crane or a chain block. Also, because assembly work does not require high-altitude work like the upper lining wall, a segment assembly device such as that shown in Patent Document 1 was not used. This conventional assembly method requires the setup of changing the lifting machine and assembly platform for each row of segments, making the assembly work less efficient. Moreover, it is not easy to adjust the hanging position using the lifting machine during assembly, and there are issues such as ensuring assembly precision, and these issues become particularly pronounced when the segments are heavy.

The object of the present invention is to provide an assembly device for lower half segments of a tunnel that enables shortening of the assembly work time for assembling segment pieces in the construction of the lower half segments of a tunnel and makes it easier to ensure assembly precision, and an assembly method using the assembly device.

To achieve the above object, the assembly device for the lower half of a tunnel segment of the present invention is characterized by comprising a guide device that is placed at the bottom between the parallel tunnels and has a curved guide beam that bulges downward, and an erector device that runs on the guide beam in the extension direction of the guide beam and grasps and transports the segment pieces that make up the segments of the lower lining wall toward the assembly position.

The method for assembling the lower half of a tunnel segment of the present invention is a method for assembling a segment of a lower lining wall that is constructed to form a curved shape that bulges downward as an outer shell at the bottom of a widening excavation construction section formed between parallel tunnels underground, and is characterized in that the assembly device is used to transport the segment pieces to an assembly position using an erector device that runs on a guide beam arranged along the curvature of the underside of the lower lining wall at the bottom between the parallel tunnels, and then the segments are assembled.

In the present invention, even if the direction of curvature of the segments is different from that of Patent Document 1, the use of the segment assembly device eliminates the need for moving and transporting using a lifting machine as in the conventional method of constructing a lower lining wall. The segment pieces can be transported to a predetermined position while placed on the erector device in a roughly assembled position, and then assembled. In addition, if a means for finely adjusting the gripping position of the segment pieces is provided on the gripping section on which the segment pieces are placed on the erector device, the assembly state can be controlled before joining. Therefore, even if the segment pieces are large and heavy, the segments can be assembled in a relatively short time. This is particularly effective when assembling the segment pieces at both the left and right ends of the segment assembly position where the gap with the existing lining tunnel is narrow. As a result, not only can the lower lining wall be constructed efficiently, but construction accuracy can also be easily ensured.

The segment assembly device is installed in the bottom widening excavation section below the lower lining wall, and is equipped with a guide beam movement device that can move on rails installed in the widening excavation base plate section, making it possible to move in the direction of travel for each row of segments to be assembled. This eliminates the need for temporary assembly stands to temporarily install the segments and temporary traveling cranes to lift the segments, which are required for each row of segments to be moved. This reduces the amount of setup work and improves construction efficiency.

The erector device of the segment assembly device has a traveling device section on which each segment piece is placed and which travels and transports it in the direction of the curvature of the guide beam, and a gripping device section on which each segment piece is placed and gripped, and which moves it in the forward and backward directions of the tunnel extension. In this way, each segment piece can be placed on the gripping device section in front of the construction position of the lower lining wall, following its curvature, and transported to the specified position. At the same time, by providing the gripping device section with a gripping section moving device that can slide in the forward and backward directions with the stroke required for assembling each segment piece, each segment piece can be moved to the joint surface of the existing segment. The K segment piece to be assembled last is transported to the specified position further forward than the other segment pieces after assembly, so the maximum movement stroke of the gripping section moving device can be the stroke required for that assembly.

In addition, each segment piece is moved along the lower lining wall in front of the construction position of the lower lining wall. This minimizes the radial space required for assembling each segment piece, including the narrow assembly areas at both ends of the segment assembly position, making it possible to use the system in an underground space with limited space.

As described above, the present invention has the effect of making it easy to construct lower lining walls in the widening excavation section between tunnels.

Overall cross-sectional front view showing an excavation construction section having a lower covering wall. Simplified plan view showing the lower covering wall. A simplified plan view of the lower covering wall showing the assembly method of segment pieces other than the K segment piece. A simplified plan view of the lower covering wall showing how to assemble the K segment pieces. Front view showing the assembly device for the existing lower lining wall and the lower half of the tunnel segment. FIG. 2 is a plan view showing the assembly device for the lower half tunnel segments. FIG. 2 is a side view showing the assembly device for the lower half tunnel segments. FIG. 4 is a cross-sectional plan view showing the relationship between the guide device and the erector device. 1A is a plan view showing a portion of a traveling device of an erector apparatus, and FIG. 1B is a plan view showing a gripping attitude adjustment unit. This is a plan view showing the operating stroke expansion means of the erector apparatus with the gripping portion moved to the new installation side. This is a plan view showing the operating stroke expansion means of the erector apparatus with the gripping portion moved to the existing side. FIG. 2 is a front view of an erector device showing the gripping state of a segment piece. FIG. 4 is a front view showing a portion of the gripping frame and the operating stroke enlarging means. FIG. 11 is a side view of the erector device portion showing a state in which the gripping portion is disposed in a position for traveling when gripping the first to fifth segment pieces. FIG. 13 is a side view of the erector device portion showing the state in which the segment piece is brought close to the existing segment. A side view of the erector device part showing the state in which the segment piece is joined to the existing segment. FIG. 13 is a side view of the erector device portion showing the state in which the gripping portion is positioned in the traveling position while gripping the K segment piece.

[Description of the embodiment]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
(Outline of the configuration and construction method of the widening excavation construction section 10 and the segments 22)
FIG. 1 shows the entire widening excavation construction section 10 installed underground. This widening excavation construction section 10 extends in a direction perpendicular to the plane of the paper in FIG. 1 and includes existing tunnel linings 11 that constitute two existing cylindrical tunnels 12 extending in the extension direction.

As shown in FIG. 1, an upper widening excavation section 15 and a lower widening excavation section 16 are formed between the existing tunnel linings 11, and an unexcavated section 18 is left in the vertical middle between them. An upper lining wall 13 is provided as an outer shell on the ceiling of the upper widening excavation section 15. A bottom widening excavation section 17 is formed at the bottom of the lower widening excavation section 16. A lower lining wall 14 is also provided as an outer shell on the upper part of this bottom widening excavation section 17, i.e., on the lower part of the lower widening excavation section 16. After the construction of the segment 22 as the lower half segment of the tunnel of the lower lining wall 14, a filling material called backfill material 19 is filled in the bottom widening excavation section 17 below the lower lining wall 14. The lower lining wall 14 after the construction of the tunnel in the widening excavation section 10 is supported from below by this backfill material 19.

As shown in Figures 1 and 5, the lower lining wall 14 bulges downward and forms an arc shape with a large radius of curvature. This lower lining wall 14 is joined to the existing tunnel linings 11 on both sides at both left and right ends, and is configured along the extension direction of the existing tunnel 12. In this embodiment, the left and right direction in Figure 1 is referred to as the left and right direction of the segment 22. Also, the upper side of Figures 2 to 4 is the rear side in the tunnel extension direction, and the lower side of the same figures is the front side in the tunnel extension direction. The segments 22 are constructed sequentially from the rear side to the front side.

As shown in Figures 1 to 4, this segment 22 has joint surfaces on the outer periphery of the first to sixth segment pieces 231 to 236. Hereinafter, when the segment pieces are collectively referred to without specifying the first to sixth segment pieces 231 to 236, they will be referred to as segment pieces 23. The joint surfaces of the first to sixth segment pieces 231 to 236 are joined to the adjacent existing segment 22 and existing tunnel lining 11, and to each newly constructed segment piece 23 by fastening bolts (not shown). Note that the above "first to sixth" are given according to the assembly order of each segment piece 23, and they are assembled alternately from both the left and right ends of the segment 22 toward the center.

As shown in FIG. 12, each segment 22 is composed of a steel shell 221 and concrete 222 filled within the steel shell 221. The segments 22 handled by the segment assembly device 20 of this embodiment are not limited to a bolt-joining method for each segment piece 23 or a structure in which concrete 222 is filled into the steel shell 221. Also, in this embodiment, one row of segments 22 is divided into six parts, but the number of parts varies depending on conditions such as the shape of the widening excavation construction section 10, so the number of each segment piece 23 is not limited to this.

As shown in FIG. 4, the sixth segment piece 236 is the K-segment piece that is assembled last among the segment pieces 23 in this embodiment. The joint surfaces at both ends of the sixth segment piece 236 are outer tapered surfaces 241 that converge toward the rear side. The other first to third segment pieces 231 to 233 are A-segment pieces, and the fourth and fifth segment pieces 234, 235 are B-segment pieces. The fourth segment piece 234 and the fifth segment piece 235 have inner tapered surfaces 242 that are aligned with the outer tapered surfaces 241 on their opposing surfaces. After the fourth segment piece 234 and the fifth segment piece 235 are assembled, a gap 237 is formed between the inner tapered surfaces 242, and the sixth segment piece 236, which is a K-segment piece, is inserted into this gap 237 from the front side. The A-group row and the B-group row are assembled alternately for each row. In the A-group row and the B-group row, the overall arrangement, including the position of the sixth segment piece 236, which is a K-segment piece, is reversed in the left-right direction. For this reason, as shown in FIG. 2, the joint positions at both the left and right ends of each segment piece 23 are staggered and not in a continuous line in the fore-and-aft direction (tunnel extension direction).

The first to sixth segment pieces 231 to 236 are assembled in the following order.
First, as shown in FIG. 3, the first segment piece 231 is transported and supplied by a segment piece supply device 25 having a bogie structure, which is installed on the supply position center 251 of the segment piece 23 at the center of the segment 22. The first segment piece 231 is then placed on and gripped by the gripping device unit 80 of the erector device 27. The position where the first segment piece 231 is placed is a gripping position 831 (hereinafter referred to as the gripping position 831 during AB segment travel) at the start of travel transportation of the first to fifth segment pieces 231 to 235 on the front side of the existing segment 22. The first segment piece 231 is then transported in the left-right direction in the gripped state toward a predetermined assembly position. Next, the first segment piece 231 is moved rearward toward the assembly position, and the rear surface is attached to the front surface of the existing segment 22, and the outer end surface is attached to the existing tunnel lining 11.

Next, the second segment piece 232 is assembled in a similar manner to the first segment piece 231 at a predetermined assembly position at an end portion that is on the left-right opposite side of the assembly position.
In this manner, thereafter, the third to fifth segment pieces 233 to 235 are attached in the same manner as described above for each assembly of the segment pieces 23. That is, the third to fifth segment pieces 233 to 235 are fixed and attached alternately on the left and right sides to the front surface of the existing segment 22 and to the side end surfaces of the already assembled segment pieces 231 to 233.

As shown in FIG. 4, the sixth segment piece 236, which is a K-segment piece, is supplied to a position where it does not interfere with the already assembled fifth segment piece 235. This position is the gripping position 832 (hereinafter referred to as the K-segment gripping position 832) of the sixth segment piece 236 during traveling transport, which is forward of the installation positions of the first to fifth segment pieces 231 to 235. The sixth segment piece 236 is then placed on and gripped by the gripping device section 80 of the erector device 27, and then travels and transports. The sixth segment piece 236 is then moved toward the gap 237 between the fourth segment piece 234 and the fifth segment piece 235, and inserted into the gap 237. The sixth segment piece 236 is then attached to the front surface of the existing segment 22 and the inner tapered surface 242 of the side end surface of the fourth segment piece 234 and the fifth segment piece 235.

(Entire construction device for lower covering wall 14)
Next, mainly based on the drawings from Fig. 5 onwards, a construction device for the lower covering wall 14 for constructing the segments 22 will be described. The construction device has a segment piece supply device 25, a guide device 26 that constitutes the segment assembly device 20, and an erector device 27. Hereinafter, the segment piece supply device 25, and the guide device 26 and erector device 27 that constitute the segment assembly device 20 will be described in order.

(Segment Piece Supply Device 25 and Related Configurations)
2 to 5 and 7, each segment piece 23 is conveyed and supplied by the segment piece supply device 25 along the front-rear direction on the supply position center 251 to the AB segment running time gripping position 831 and the K segment running time gripping position 832. Then, each segment piece 23 is supplied from the segment piece supply device 25 to the segment assembly device 20 at the AB segment running time gripping position 831 and the K segment running time gripping position 832 (see FIGS. 3 and 4). The segment assembly device 20 includes an erector device 27, and each segment piece 23 is delivered to a gripping frame 82 serving as a gripping device unit 80 (described later) of the erector device 27.

As shown in Figures 5 and 7, a bottom-side rail 311 and an existing-side rail 312 extending in the front-rear direction are laid on the left and right two locations on the bottom-widening excavation section 17 and the existing segment 22. The carriage frame 32 of the segment piece supply device 25 arranged to straddle the guide device 26 has wheels 33 at four positions, front, rear, left and right. The segment piece supply device 25 is mounted on these wheels 33 so that it can move forward and backward on the bottom-side rail 311 on the front side and the existing-side rail 312 on the rear side. The segment piece supply device 25 is moved forward and backward by the extension and contraction of the moving cylinder 34 as an actuator. That is, one end of the moving cylinder 34 is attached to the segment piece supply device 25, and the rail clamp 341 at the other end clamps the existing-side rail 312. Then, the moving cylinder 34 is extended to move the segment piece supply device 25 forward. After that, the rail clamp 341 releases the clamp on the existing-side rail 312. Next, after the moving cylinder 34 contracts, the rail clamp 341 clamps the existing rail 312 again. In this manner, the segment piece supply device 25 advances intermittently. A crane unit 35 that is movable in the forward and backward directions along the I-beam 36 of the carriage frame 32 is supported on the carriage frame 32. In FIG. 5, the front wheels 33 are shown to the left of the dashed line C-C, and the rear wheels 33 are shown to the right.

Each segment piece 23 carried in from the rear side of the tunnel extension direction by a segment supply cart (not shown) is suspended piece by piece at the rear side of the segment piece supply device 25 by the crane unit 35 and supplied to the front position. Then, at this front position, each segment piece 23 in the suspended state is changed in orientation in the horizontal plane and lowered. Meanwhile, the erector device 27 is stopped running with its center position aligned with the supply position center 251. Then, the gripping frame 82 of the erector device 27 is set to the AB segment traveling gripping position 831 or the K segment traveling gripping position 832 in the front-rear position. Then, each segment piece 23 is rotated so that the curvature direction becomes the left-right direction before being lowered from the suspended state, and is lowered onto the gripping frame 82 at the AB segment traveling gripping position 831 or the K segment traveling gripping position 832. Note that the moving cylinder 34 may adopt a mechanism such as a motor, which is a configuration other than the actuator, as an actuator.

(Guide device 26)
Next, the guide device 26 for guiding the traveling movement of the erector device 27 will be described.

As shown in Figures 5 to 7, the guide device 26 is disposed in the bottom widening excavation section 17 at the unfilled position of the backfill material 19, and is mounted on the bottom rail 311 so as to be movable forward and backward via wheels 33 at the front and rear positions. The guide device 26 is moved forward (to the left in Figure 7) by the moving cylinder 42 as a guide beam moving device and actuator. That is, one end of the moving cylinder 42 is attached to the guide device 26, and the rail clamp 421 at the other end clamps the bottom rail 311. The guide device 26 is then advanced by the contraction of the moving cylinder 42. After that, the rail clamp 421 releases the clamp on the bottom rail 311. Next, after the moving cylinder 42 extends, the rail clamp 421 clamps the bottom rail 311 again. In this way, the guide device 26 is advanced intermittently.

As shown in Figures 5 and 6, the guide device 26 has a pair of guide beams 44 consisting of a front and rear I-shaped beams connected by a plurality of connecting members 43 at the center and both ends of the guide device 26. Both guide beams 44 are curved so as to bulge downward along the curve of curvature of the lower surface of the segment 22 that constitutes the lower covering wall 14. As shown in Figure 14, in order to run the erector device 27, a running rail 40 is extended on the inner surface of the lower flange 443 on the opposing side of both guide beams 44, and a running rack 45 is extended on the inner surface of the upper flange 444.

As shown in Figures 5 and 6, outrigger jacks 461 are attached to the underside of both guide beams 44 near both ends of a pair of connecting members 43 in the center of the guide beam 44 in the left-right direction. When the outrigger jacks 461 are extended, the outrigger shoes 462 at the lower ends of the guide beams 44 contact the bottom plate of the bottom widening excavation section 17, pushing up the entire guide device 26 and lifting the wheels 33 from the bottom plate side rail 311. When the outrigger jacks 461 are contracted, the entire guide device 26 is lowered, the wheels 33 are placed on the bottom plate side rail 311, and the outrigger shoes 462 are separated from the bottom plate of the bottom widening excavation section 17.

As shown in Figures 6 and 7, a hem panel 49 is provided on the rear side of the rear guide beam 442 via a hem support material 48. This hem panel 49 functions as a hem when filling the backfill material 19 into the bottom widening excavation section 17 below the lower lining wall 14 after constructing the segments 22, which are the lower lining wall 14, in the bottom widening excavation section 17 below the lower lining wall 14. The backfill material 19 may be filled each time multiple rows of segments 22 are installed in the construction cycle. Note that the hem panel 49 of the backfill material 19 is not directly related to the assembly of the segments 22, and the hem may be formed by a separate method, and these configurations are not limited to this embodiment.

As shown in Figures 6 and 14, a number of guide receiving tables 51 are attached at equal intervals in the left-right direction to the upper surface of the rear guide beam 442 and the upper surface of the rear side of the frame support material 48. Guide rollers 52 made of free balls are supported on these guide receiving tables 51. If the frame panel 49 is omitted, the frame support material 48 will be an extension material of the same structure installed behind the guide beam 442 for the installation of the guide receiving tables 51.

As shown in Figures 6 and 14, a travel guide frame 53 is fixed to the front of the center of the front guide beam 441 in the left-right direction, which guides the K segment, which is the sixth segment piece 236, from its supply position to a predetermined assembly position. This travel guide frame 53 guides the travel of the gripper support rollers 87 provided at the front lower part of the gripper frame 82 described below. The upper surface of this travel guide frame 53 is continuous with the upper surface of the upper flange 444 of the front guide beam 441. At three left-right locations on the upper surface of the travel guide frame 53, guides 54 to 56 of the travel paths described below for each pair of gripper support rollers 87 extending in the front-rear direction are formed.

The pair of supply position guides 54, which are the running paths in the center of the front guide beam 441, are arranged on both sides of the supply position center 251. The pair of A row K position guides 55, which are the running paths on the left side as viewed from the front of the front guide beam 441, are provided in front of the assembly position of the sixth segment piece 236 of the A row of the segment 22. The pair of B row K position guides 56, which are the running paths on the right side as viewed from the front of the front guide beam 441, are provided in front of the assembly position of the sixth segment piece 236 of the B row of the segment 22. The front ends of the supply position guide 54, A row K position guide 55, and B row K position guide 56 are connected by a K gripping running guide 57. This K gripping running guide 57 is arranged on a left-right line passing through the K segment running grip position 832. This K gripping travel guide 57 guides the travel of the gripper support roller 87 from the supply position guide 54, which is the supply position of the sixth segment piece 236, to the A row K position guide 55 or the B row K position guide 56. The supply position guide 54, the A row K position guide 55, and the B row K position guide 56 guide the forward and backward travel of the gripper support roller 87 between the position of the K gripping travel guide 57 and the position of the front guide beam 441.

(Erector Apparatus 27)
Next, an explanation will be given of the erector device 27 for transporting each segment piece 23 to a predetermined assembly position after it is supplied to the AB segment running gripping position 831 and the K segment running gripping position 832. As shown in Figures 8, 9(a), 9(b), 12 and 14, the erector device 27 is broadly composed of a traveling device unit 60, a gripping attitude adjustment unit 70, and a gripping device unit 80.

The traveling device section 60 of the erector device 27 will be described. As shown in Figures 8, 9(a) and 14, the framework of the traveling device section 60 is formed by a traveling frame section 61. Traveling wheels 62 are arranged at each of the four corners of the traveling frame section 61. The traveling wheels 62 roll on the traveling rails 40 of the lower flanges 443 of both guide beams 441 and 442, and this rolling causes the erector device 27 to travel left and right along the extension direction, which is the curvature direction of the guide beam 44. A pair of traveling drive motors 641 are mounted on the traveling frame section 61, and a traveling pinion 642 is attached to each of the output shafts to form a traveling drive section. The traveling pinion 642 meshes with the traveling rack 45 of the upper flanges 444 of both guide beams 441 and 442. Driven by the travel drive motor 641, the travel pinion 642 meshes with and rotates on the travel rack 45, causing the erector device 27 to travel on the guide beam 44. Four side wheels 621 are supported on the travel frame portion 61, which travel on the opposing inner end faces of the upper flange 444 of the guide beam 44 and guide the travel position in the forward and backward directions.

As shown in Figures 8 and 14, a pair of support plates 65 are provided at the front and rear of the running frame section 61. Between the two support plates 65 in the center of the running frame section 61, the gripping posture adjustment section 70 described below is supported from the front and rear by a pair of support pins 651 fixedly protruding from both support plates 65.

As shown in Figures 8, 9(a), 9(b) and 12, the configuration of the gripping posture adjustment unit 70 and the posture adjustment method will be described. A support frame 72 on which the gripping device unit 80 described later is mounted is disposed on the upper part of the gripping posture adjustment unit 70. A receiving ring 74 is fixed to the center of the lower surface of the support frame 72. A support shaft 73 is provided on the lower surface of the support frame 72 in a manner inserted into the receiving ring 74. The support shaft 73 is rotatably inserted into a bearing 68 fitted into a support shaft hole 67 that penetrates the support shaft boss material 66. The bearing 68 has a bearing flange portion 681 on the upper part, and its upper surface contacts the receiving ring 74 of the support frame 72 to receive the load acting on the support frame 72 when each segment piece 23 is placed. As a result, the support frame 72 is supported by the support shaft boss material 66 in a manner that allows it to rotate within a substantially horizontal plane.

8, 9(b) and 12, a vertically long boss support hole 69 is provided on the outer front-rear direction of the support shaft boss material 66, into which a fixed support pin 651 is inserted on the pair of support plates 65 of the running frame part 61. When the segment pieces 23 are not placed, or when the support jack 97 described later is extended and not in contact with the lower surface of each segment piece 23 when the segment is placed, a downward load acts on the support shaft boss material 66. At this time, the support shaft boss material 66 is located on the lower side, and the support pin 651 is located at the top of the boss support hole 69, and supports the load from above via the support pin 651. Also, when each segment piece 23 is placed on the gripping device part 80 and the support jack 97 is in contact with the lower surface of each segment piece 23 and pushed up together with the gripping device part 80, the support shaft boss material 66 is pushed up. Then, the support pin 651 comes into contact with the bottom of the boss support hole 69, and the amount of pushing up of the segment piece 23 is regulated.

As described above, the gripping posture adjustment unit 70 can adjust the posture in three directions: pitching (front-rear tilt), rolling (left-right tilt), and yawing (tilt in a horizontal plane). The pitching direction is adjusted as follows. That is, a clearance (not shown) is provided between the front and rear surfaces of the support plate 65 and the support shaft boss material 66 of the running frame unit 61, and the vertical positions of the support pins 651 in the front and rear boss support holes 69 are moved, allowing the front-rear tilt of the support frame 72 to be adjusted. In the rolling direction, the left-right tilt can be adjusted with the support pin 651 provided on the support plate 65 of the running device unit 60 as a fulcrum. In the yawing direction, the planar tilt in a horizontal plane can be adjusted with the axis of the support shaft 73 provided on the support frame 72 as the center. The details of each operation will be described later.

8 and 12, support jacks 97 are arranged at the four corners of the outer periphery of the traveling frame part 61, and support rollers 98 made of free balls are attached to the upper end of the upward-facing piston rod of each support jack 97. The support jack 97 abuts the four support rollers 98 on the underside of each segment piece 23 placed on the gripping device part 80 described later. Then, by simultaneously extending and retracting the support jacks 97 with the same stroke, each segment piece 23 can be raised and lowered together with the gripping device part 80 and the gripping attitude adjustment part 70 to adjust the vertical position. As shown in FIG. 14, when the segment pieces 231 to 235 are placed on the erector device 27 at the gripping position 831 during AB segment traveling and travel on the guide device 26, the support rollers 98 of the two front support jacks 97 abut against the segment piece 23. This allows the gripping attitude of each segment piece 23 to be stably supported.

Of the posture adjustment directions of the grip posture adjustment unit 70, the pitching direction and rolling direction are possible by operating the support jack 97. By adjusting the different strokes of each piston rod of the front and rear support jacks 97 to adjust the vertical position of the support section roller 98, the posture of each segment piece 23 can be adjusted in the pitching direction together with the grip device unit 80 and grip posture adjustment unit 70. In addition, by adjusting the different strokes of each piston rod of the left and right support jacks 97 to adjust the vertical position of the support section roller 98, the posture of each segment piece 23 can be adjusted in the rolling direction together with the grip device unit 80 and grip posture adjustment unit 70.

As shown in Figs. 8 and 14, the gripping attitude adjustment unit 70 has the following configuration for adjusting the yawing direction. That is, a yawing jack 76 is connected between the running frame unit 61 and the side of the support frame 72 via universal joints 77 at both ends. Due to the effect of this universal joint 77, even during the up/down movement and pitching/rolling adjustment of the gripping device unit 80, the extension and contraction of the yawing jack 76 causes the support frame 72 to rotate about the axis of the support shaft 73. This allows the inclination of the support frame 72 in the yawing direction within a plane to be adjusted.

The gripping device section 80 of the erector device 27 will now be described. As shown in Figures 12 and 14, the gripping frame 82 constituting the gripping device section 80 is used to place and grip and fix each segment piece 23. The gripping frame 82 has a structure in which a fixing plate 822 is erected on the upper surface of the front end of a pair of left and right gripping beams 821, which are elongated in the front-rear direction. Each segment piece 23 is placed on the upper surface of the gripping beams 821 in a gripped state at the center with the left and right directions curved. In addition, several fixing bolts 823 are attached to the fixing plate 822. The fixing bolts 823 are screwed into the screw holes 238 on the front surface of each segment piece 23 to fix each segment piece 23 to the gripping frame 82.

The gripping unit moving device 83 constituting the gripping device unit 80 that moves the front gripping frame 82 on the support frame 72 from the gripping position 832 when the K segment is traveling to the joining position of each rear segment piece 23 with the existing segment 22 will be described.

As shown in Figures 10 to 13, a pair of left and right support side guide rails 85 extending in the front-rear direction are laid on the support frame 72 as sliding guides on the side of the support frame 72, which is the fixed side of the gripper moving device 83. The lower recess 841 of the slider 84 is placed on both support side guide rails 85 so that it can slide in the front-rear direction within the movable range. The upper recess 842 on the upper side of the slider 84 supports the moving side guide rails 86 on both outer sides of the gripping beam 821 at the lower part of the gripping frame 82, which is the moving side, so that it can slide in the front-rear direction. Therefore, the gripping frame 82 can move in the front-rear direction with a stroke that is the sum of the movable distances of the slider 84 relative to both guide rails 85, 86. This reduces the overall length of the guide mechanism when the stroke is contracted, and saves space in the mounting parts. The slider 84 is restricted by a stopper (not shown) so that it does not slip out of the support side guide rails 85 forward or backward on the support frame 72.

As shown in FIG. 14, gripper support rollers 87 made of free balls are provided at two locations, left and right, in front of the moving guide rail 86 on the underside of the front end of the gripper frame 82. As the gripper frame 82 moves back and forth, the gripper support rollers 87 travel on the front upper surface (not shown) of the running frame section 61, the upper surface of the upper flange 444 of the front guide beam 441, and each of the guides 54 to 57 of the running guide rack 53. The gripper support rollers 87 support the load acting on the gripper frame 82, and suppress the action of the offset load on both guide rails 85, 86 and the slider 84 when the position of the point of application of the load deviates forward from the length of the slider 84.

The operating mechanism of the gripper moving device 83 in the gripper unit 80 will now be described.
As shown in Figures 10 to 13, a sliding reaction support beam 88 is fixed to the upper surface of the center part of the support frame 72, extending in the front-rear direction, and a fixed side rack 89 and a regulating rail 90 extending in the front-rear direction are attached to both sides of the beam. On the other hand, a moving side rack 91 extending parallel to the fixed side rack 89 is attached to both the left and right sides of the inside of the gripping beam 821 at the lower part of the gripping frame 82. A pair of sliding jacks 96 are provided in front of the left and right fixed side racks 89 of the sliding reaction support beam 88, and a sliding pinion 92 is provided via a link bar 94 to a clevis 962 at the rear end of each piston rod 961 of each of these sliding jacks 96. The sliding pinion 92 is provided between the left and right fixed side racks 89 and the moving side rack 91 in a form that meshes with both of them, forming a multi-stage rack mechanism 99 as a speed-doubling mechanism. The gripping frame 82 is moved by the extension and contraction of the sliding jack 96, utilizing the speed multiplying effect of the multi-stage rack mechanism 99, which will be described below.

The operation of the gripper moving device 83 is as follows. That is, when the piston rod 961 of the sliding jack 96 is extended, the sliding pinion 92 is moved backward via the link bar 94. At this time, the sliding pinion 92 moves and rotates while meshing on the fixed rack 89, and the moving rack 91 moves backward due to this rotation, and the amount of movement due to the extension operation of the piston rod 961 of the sliding jack 96 is added, and it is moved backward at double speed. On the other hand, when the sliding jack 96 is contracted, the sliding pinion 92 meshes with the moving rack 91 while rotating on the fixed rack 89 in the opposite direction to when it is extended. Therefore, the moving rack 91 moves forward, and the amount of movement due to the contraction operation of the piston rod 961 of the sliding jack 96 is added, and it is moved forward at double speed.

The manner in which the sliding pinion 92 is attached to the sliding jack 96 will be described. As shown in Figures 10 to 13, the front end of a bent link bar 94 is connected to a clevis 962 at the tip of a piston rod 961 of the sliding jack 96 by a pin support. The sliding pinion 92 is supported rotatably by a pinion shaft 93 at the center of the link bar 94, and a guide roller 95 that can roll on the regulating rail 90 is supported at the rear end of the other end. Therefore, when the sliding jack 96 is extended, the inner side of the clevis 962 at the tip of the piston rod 961 slides while contacting the regulating rail 90 of the sliding reaction support beam 88 with the pinion shaft 93 as a fulcrum. When the piston rod 961 is contracted, the guide roller 95 at the rear end of the link bar 94 moves while rolling in contact with the regulating rail 90 with the pinion shaft 93 as a fulcrum.

Based on this configuration, it is possible to prevent bending force due to thrust acting on the piston rod 961 when the axis of the sliding jack 96 is offset inward from the center of rotation of the sliding pinion 92 due to space restrictions on the installation of the sliding jack 96. Note that in cases where there are no restrictions on the installation space of the sliding jack 96 and the axis of the sliding jack 96 can be aligned with the center of rotation of the sliding pinion 92, the adoption of a form in which the sliding pinion 92 is installed using a bent link bar 94 is not limited to this.

By adopting the multi-stage rack mechanism 99, the gripping frame 82 is moved at a speed (twice as fast) faster than the extension and retraction speed of the piston rod 961 of the sliding jack 96. Therefore, the gripping frame 82 having the moving rack 91 is moved forward and backward with a stroke twice that of the sliding jack 96 as the drive unit. Therefore, it is possible to equip a sliding jack 96 with a stroke half the required distance of the gripping frame 82, reducing the length of the sliding jack 96 and saving space in the mounting section. In addition, the length of the piston rod 961 of the sliding jack 96 is reduced, which is advantageous in terms of buckling strength. In addition, in addition to the bending strength measures taken by adopting the link bar 94, the diameter of the piston rod 961 can be made thinner, so the diameter of the sliding jack 96 can be made smaller.

(Action of the Construction Device)
Next, the operation of the construction device for the lower covering wall 14 will be described.
2 to 4, each segment piece 23 of the segment 22 is supplied one by one by the segment piece supply device 25 onto the gripping frame 82 of the erector device 27 at a predetermined traveling gripping position 831, 832 on the supply position center 251 of each piece. Then, the erector device 27 of the segment assembly device 20 travels along the guide beam 44. Furthermore, the gripping frame 82 is moved backward, and each segment piece 23 is fixed to the existing segment 22 and each adjacent segment piece 23. In this manner, the segments 22 are assembled in sequence, and the lower covering wall 14 is constructed.

As shown in Figures 5 to 7, when installing the segment assembly device 20 before assembling each segment piece 23, the four outrigger jacks 461 provided on the guide device 26 are retracted and the wheels 33 of the guide device 26 are placed on the base plate side rail 311. Then, the movement cylinder 42 of the guide device 26 is operated to move the guide device 26 to the assembly position of each newly installed segment piece 23. After moving to that assembly position, the outrigger jacks 461 are extended, and the outrigger shoes 462 at the tips come into contact with the base plate portion, and the entire segment assembly device 20 is raised.

By doing this, the guide rollers 52 attached to the two rows of guide receiving tables 51 provided behind the guide device 26 can be pressed against the underside of the existing segment 22. As a result, the centering effect caused by the rolling of the guide rollers 52 causes the position where the curvature of the guide beam 44 is formed to match the position where the outer diameter curvature of the existing segment 22 is formed, and the vertical position of the guide device 26 is determined. In addition, the front end of the front guide receiving table 51 installed on the upper surface of the upper flange 444 of the rear guide beam 442 protrudes from the rear end of the lower surface of the assembly position of each segment piece 23 of the existing segment 22. Therefore, if each segment piece 23 of the new segment 22 is placed on it and assembled, the surfaces of the new segment 22 and the outer peripheral surface of the existing segment 22 can be aligned. Furthermore, the reaction force of various assembly loads generated when the segment pieces 23 are assembled by the erector device 27 can be supported by the bracing effect caused by the extension of the outrigger jack 461.

The method of assembling the A-group of each segment piece 23 will be described in detail below. That is, as is clear from FIG. 3, when the first to fifth segment pieces 231 to 235 are supplied, the erector device 27 is positioned in alignment with the supply position center 251. At this time, as shown in FIG. 14, the gripping frame 82 is set to the gripping position 831 during AB segment travel by the operation of the sliding jack 96. In this state, the gripping section support roller 87 on the lower surface of the gripping frame 82 is positioned on the upper surface of the upper flange 444 of the front guide beam 441, and the first segment piece 231 is supplied from the segment piece supply device 25 onto the gripping frame 82. In this case, as shown in FIG. 12, the first segment piece 231 is placed so that its curvature direction is along the left-right direction of the segment 22. The first segment piece 231 placed on the gripping frame 82 is fixed to the fixing plate 822 by the fixing bolt 823 and is in a gripped state. Additionally, the first segment piece 231 is supported from below by two support jacks 97 on the front side.

Then, as shown in FIG. 3, the erector device 27 holding the first segment piece 231 is transported along the guide beam 44 to the front of the assembly position of the first segment piece 231. Next, as shown in FIG. 15 and FIG. 16, the gripping frame 82 is moved further rearward from the gripping position 831 during AB segment travel by the operation of the sliding jack 96. As a result, the rear surface of the first segment piece 231 is joined to the front surface of the existing segment 22, and the outer end surface is joined to the existing tunnel lining 11 and fastened with bolts. Before joining the first segment piece 231, the position of the first segment piece 231 is adjusted in the yawing, rolling and pitching directions by the yawing jack 76 and the support jack 97 as necessary.

When the gripping frame 82 is moved to a rear position on the existing segment 22 side, the first segment piece 231 is moved until it can abut against the support rollers 98 of the four support jacks 97. At this position, the gripping frame 82 is raised together with the first segment piece 231 to the regulated upper limit of the stroke of the support jack 97. In this way, the first segment piece 231 placed on the gripping frame 82 is raised so that the underside of the first segment piece 231 does not come into contact with the guide receiving base 51 on the rear guide beam 442. Then, when the first segment piece 231 is assembled to the existing segment 22, the rear lower end of the first segment piece 231 is placed on the protruding portion of the guide receiving base 51 from the existing segment 22.

Then, the first segment piece 231 is released from the fixing plate 822 by the fixing bolt 823. Then, the gripping device part 80 of the erector device 27 is returned to the gripping position 831 during AB segment travel, and the erector device 27 is moved back to the supply position center 251 position. Then, in a similar manner, the second segment piece 232 is supplied onto the gripping frame 82, and the second segment piece 232 is moved to the assembly position and assembled to the end on the opposite left and right side to the first segment piece 231 in the same manner.

In this manner, the first to fifth segment pieces 231 to 235 are assembled to the adjacent existing segment 22 and existing tunnel lining 11, and to each of the new segment pieces 23.
As shown in FIG. 17, in assembling the sixth segment piece 236, after assembling the fifth segment piece 235, the gripping frame 82 is returned to the gripping position 831 during the AB segment travel. Also, the gripping device unit 80 of the erector device 27 is returned to the position of the supply position guide 54 of the travel guide frame 53 at the supply position center 251. In this state, the gripping frame 82 of the gripping device unit 80 is moved to the gripping position 832 during the K segment travel, which is located in front of the first to fifth segment pieces 231 to 235, by the operation of the sliding jack 96. At this time, the gripping unit support roller 87 on the lower surface of the gripping frame 82 is moved to the front end position on the supply position guide 54 of the travel guide frame 53 shown in FIG. 6. This position is located forward of the first to fifth segment pieces 231 to 235 that have already been assembled, and here, the sixth segment piece 236 is supplied onto the gripping frame 82.

In this state, the erector device 27 travels toward the assembly position of the sixth segment piece 236 without interfering with the fifth segment piece 235. During this movement, the gripping support rollers 87 of the gripping frame 82 travel on the K gripping travel guide 57 of the travel guide stand 53.

When the sixth segment piece 236 faces its installation position, as shown in Figures 4 and 16, the sliding jack 96 is operated to move the gripping frame 82 rearward with a large stroke via the gripping movement device 83. The gripping support roller 87 of the gripping frame 82 travels rearward on the guide beam 44 via the K gripping travel guide 57 and the A-row K position guide 55, and the sixth segment piece 236 is inserted into the gap 237 between the fourth and fifth segment pieces 234, 235. The sixth segment piece 236 is adjusted in position by yawing or the like before joining with the existing segment 22 and the fourth and fifth segment pieces 234 and 235, and is fastened to the respective joining surfaces by bolts in the same manner as described above.

After the assembly of one row of segments 22 is completed in the manner described above, the guide device 26 and segment piece supply device 25 are moved forward to the assembly position of the next row of segments 22, and new segments 22 are assembled in the same manner as described above. In the next row of segments, the arrangement of each segment piece 23 is reversed in the left-right direction of the segments 22, but the lower lining wall 14 is constructed using the same assembly method. In this manner, the assembly of the segments 22 is repeated, and the lower lining wall 14 is constructed sequentially along the extension direction of the existing tunnel 12.

In this embodiment, the following effects are obtained.
(1) In the above embodiment, the guide beam 44 is arranged along the curvature of the lower surface of the lower lining wall 14, which is constructed to have a curved shape that bulges downward. By using the segment assembly device 20 constituted by the erector device 27 that runs on the guide beam 44, each segment piece 23 can be transported to a predetermined position while placed on the erector device 27 and assembled. Therefore, the need for movement and transportation using a lifting machine as in the conventional method of constructing the lower lining wall 14 is eliminated, making it possible to adopt a method of constructing the lower lining wall 14 that can be constructed in a short time.

(2) When assembling each segment piece 23, the other segment pieces 231 to 235, except for the sixth segment piece 236, which is the last to be assembled, are moved backward to the assembly position in front of the construction position of the existing segment 22 and assembled. Then, the last sixth segment piece 236 is transported at a position further forward of the construction position to avoid interference with the fifth segment piece 235 after assembly is completed, and is inserted into the gap 237 between the other segment pieces 234, 235 after assembly is completed. This makes it possible to carry out assembly work in a limited underground space, including the narrow assembly areas at both the left and right ends of the installation position of the segment 22.

(3) The segment assembly device 20 is equipped with a moving cylinder 42 for moving the wheels 33 of the guide device 26 by operating the outrigger jack 461 and placing them on the base side rail 311, and can move forward for each row of segments 22 assembled. Therefore, unlike the conventional method, there is no need to move each row of segments 22 using a temporary assembly stand on which the segments 22 are temporarily installed or a temporary traveling crane to lift each segment piece 23, reducing the amount of work required for rearrangement and improving construction efficiency.

(4) The erector device 27 includes a traveling frame section 61 as a traveling device section 60 on which each segment piece 23 is placed and travels along the curvature of the guide beam 44, and a traveling drive motor 641 as a traveling drive section that drives the traveling transport of the erector device 27. The erector device 27 also includes a gripping frame 82 as a gripping device section 80 on which each segment piece 23 is placed and supported. The erector device 27 also includes a gripping section moving device 83, which moves the gripping frame 82 to move each segment piece 23 placed on the gripping frame 82 in a state of approximately assembly in the extension direction of the tunnel, and assembles it in a predetermined position. Therefore, even if each segment piece 23 is large and heavy, it can be assembled by improving the efficiency of the assembly work of the segment 22. This is particularly effective in installing the first segment piece 231 and the second segment piece 232 at a position where the assembly space is narrow, i.e., at the left and right ends of the segment.

(5) When assembling each segment piece 23 placed and held on the holding frame 82, it is necessary to ensure a movement stroke in the extension direction of the tunnel for the holding part moving device 83. In particular, the forward and backward movement stroke of the K segment, which is the sixth segment piece 236, needs to move from the holding position 832 during K segment travel during left-right transport travel to the joint surface of the existing segment piece 23. Therefore, the forward and backward movement stroke of the sixth segment piece 236 is about twice the forward and backward width dimension of one row of the segments 22. For this reason, a speed doubling mechanism using a multi-stage rack mechanism 99 that expands the operating stroke of the sliding jack 96 and transmits it to the holding frame 82, and a guide mechanism using two-stage guide beams 44, etc., are provided. Therefore, even if the total length of the extension stroke of the sliding jack 96 during contraction is short to move the holding frame 82 in the forward and backward direction, the movement stroke in the extension direction of the tunnel required for assembling each segment piece 23 can be sufficiently ensured. This allows the erector device 27 to be made compact.

(6) The erector device 27 has adjustment means such as a yawing jack 76 and a support jack 97 as a gripping attitude adjustment unit 70 that adjusts the gripping attitude of each segment piece 23 placed on the gripping frame 82 in the pitching, rolling, and yawing directions. Therefore, the gripping attitude of each segment piece 23 can be fine-tuned by the gripping attitude adjustment unit 70 before assembly, and the segment pieces 23 can be accurately positioned and assembled relative to the assembly position. This makes it easier to ensure construction accuracy, such as preventing steps from occurring at the joint surfaces of the existing segment 22 at the rear, the existing tunnel linings 11 at both ends, and the adjacent segment pieces 23, and to construct the lower lining wall 14.

(Example of change)
This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that no technical contradiction occurs.

- In the above embodiment, the operating stroke expansion means of the gripping device unit 80 is configured as a multi-stage rack mechanism 99 with two stages of racks 89, 91. In contrast, it is possible to configure the sliding jack 96 to have multiple stages, such as two stages, without using a rack, or to use a double-acting cylinder as the sliding jack 96, so that the operating stroke of the sliding jack 96 is expanded and transmitted to the gripping frame 82.

- In the above embodiment, the speed doubling mechanism using the multi-stage rack mechanism 99 of the operating stroke enlargement means is configured to double the operating stroke of the sliding jack 96 and transmit it to the gripping frame 82. The enlargement rate of the operating stroke of each of the above means is not limited to 2 times, but may be any value greater than 1 time, for example 1.5 times, 3 times, etc.

- Omit the outrigger jack 461 of the guide device 26. Instead, provide a mechanism for extending and retracting the support leg that supports the guide device 26 and has wheels at the lower end, and configure the guide device 26 to be raised and lowered by the operation of the extension mechanism.

- As shown by the two-dot chain line in Figure 17, wheels 101 are supported on the guide device 26, and the wheels 101 are rotated and driven by a motor 103 via a chain 104. The wheels 101 are provided at four positions on the front, rear, left and right of the guide device 26, and roll on concave rails 102 laid at left and right positions on the bottom widening excavation section 17. Therefore, the guide device 26 is moved in the front-rear direction along the rails 102 by driving the motor 103. With this configuration, the moving cylinder 34 as in the previous embodiment is not necessary.

(Other technical ideas)
The technical ideas understood from the above embodiments are as follows.
(A) A method for assembling a tunnel lower half segment as described in claim 6, in which a segment piece supply device of a separate mechanism is provided at a position spanning the segment assembly device, and segment pieces are supplied from that segment piece supply device to the gripping device portion of the erector apparatus.

(B) A method for assembling a lower half tunnel segment as described in technical idea (A) above, in which segment pieces are supplied to the gripping device of the erector device by an independent transport means instead of a segment supply device.

(C) A method for assembling a lower half tunnel segment as described in paragraph (A) or (B) above, in which a separate mechanism for expanding the operating stroke is provided between the running carriage of the gripping device and the gripping frame.

10...widening excavation construction section 12...existing tunnel 14...lower lining wall 20...segment assembly device 22...segment 23...segment piece 25...segment piece supply device 26...guide device 27...erector device 31...rail 33...wheel 44...guide beam 46...outrigger device 60...traveling device section 61...traveling frame section 70...gripping attitude adjustment section 80...gripping device section 83...gripping section movement device 96...sliding jack 101...wheel 102...rail 231...first segment piece 232...second segment piece 233...third segment piece 234...fourth segment piece 235...fifth segment piece 236...sixth segment piece 237...gap 441...guide beam 442...guide beam 461...outrigger jack

Claims (7)

A guide device is disposed at the bottom of the tunnel and has a curved guide beam that bulges downward along the lower lining wall;
An assembly device for a tunnel lower half segment, comprising an erector device that runs on the guide beam in the extension direction of the guide beam and grasps and transports the segment pieces that constitute the segments of the lower covering wall toward the assembly position. The assembly device for the tunnel lower half segments described in claim 1, wherein the guide device comprises wheels for moving the guide beam in the extension direction of the tunnel, a guide beam moving device having an actuator for driving the movement by the wheels, and an outrigger device for lifting the wheels off the rails, and moves the guide beam to the next assembly position each time one row of the segments is assembled. The erector device is an assembly device for a tunnel lower half segment according to claim 1 or 2, which has a traveling device section consisting of a traveling frame section that places the segment piece on the segment piece and transports it in the curvature direction of the guide beam and a traveling drive section that drives the traveling transport of the traveling frame section, a gripping device section that places and grips the segment piece, and a gripping section moving device that moves the placed segment piece in the extension direction of the tunnel toward the existing segment. The assembly device for a tunnel lower half segment according to claim 3, wherein the gripper moving device has an operating stroke enlarging means between the gripper device part and the traveling device part for enlarging the moving stroke of the gripper device part from the operating stroke of the sliding jack in order to ensure the moving stroke of the segment piece in the extension direction of the tunnel. The erector device is an assembly device for a tunnel lower-half segment according to claim 3 or 4, which has an adjustment means using a gripping attitude adjustment unit that adjusts the position of the segment piece gripped by the gripping device unit that places and grips the segment piece in three directions, pitching, rolling, and yawing. A method for assembling a tunnel lower half segment by assembling a segment of a lower lining wall constructed to form a curved shape that bulges downward as an outer shell at the bottom of a tunnel, comprising the steps of:
A method for assembling a tunnel lower half segment, comprising using an assembly device for a tunnel lower half segment described in any one of claims 1 to 5, transporting segment pieces to an assembly position using an erector device running on a guide beam arranged along the curvature of the lower lining wall at the bottom of the tunnel, and assembling the segments. The method for assembling the tunnel lower half segment according to claim 6, in which the segment pieces constituting the segment are gripped by the gripping device of the erector device and transported on the guide beam from the position where they were supplied to the erector device to the assembly position of the segment by the movement of the erector device, and then moved in the extension direction of the tunnel to the joining position with the existing segment by the gripping device movement device, using an assembly device for the tunnel lower half segment.