JP2005068861A - Converging and branching structure of tunnel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a limitation to the installation positions of converging and branching parts. <P>SOLUTION: First and second shield tunnels 10 and 12 are constructed as a tunnel by annularly assembling segments 14 and 16. When a converging part is formed, the tunnels 10 and 12 are disposed parallel with each other and apart a specified distance from each other. A connection part 22 allowing the tunnels 10 and 12 to communicate with each other is formed between the tunnels 10 and 12 after parts of the opposed segments 14 and 16 are removed to form opening parts 18 and 20 and the outside natural grounds of the opening parts 18 and 20 are excavated. The connection part 22 is extended in the axial direction of the tunnel and comprises an upper plate 24 and a bottom plate 26. The upper and bottom plates 24 and 26 are locked at their both ends to the end edges of the opening ends 18 and 20 of the segments 14 and 16 apart a specified distance in the vertical direction. A PC steel wires 28 is installed between the tunnels 10 and 12 and the connection part 22 so as to wrap around them in a continuous state, and fixed in a tensed state. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tunnel joining and branching structure, and more particularly to a technique for stabilizing a tunnel joining and branching structure without providing a middle pillar.

  Conventionally, tunnels constructed by the shield method have been mainly tunnels with a structurally stable circular cross section. However, recently, from the viewpoint of diversifying use of underground space, congestion of underground structures, and efforts to reduce costs, a tunnel with a cross-sectional shape in which circular cross-sections are polymerized in two or three in a horizontal direction. Has been built.

  For example, in the case of a double tunnel, the cross-sectional shape of the tunnel is formed by connecting the ends of a pair of circular cross-section shield tunnels in a lateral direction so that they overlap each other. The removed portion was removed, and a segment having a substantially eyeglass cross-sectional shape was installed.

  In the tunnel having such a shape, in order to structurally stabilize the tunnel, the middle pillar is arranged for each ring of the segments. However, in such a tunnel structure, there is a problem that the lanes of the vehicle and the subway cannot be changed between the shield tunnels due to the middle pillar when it is used at the junction and branching part of the road tunnel and the connecting part of the subway. .

  Therefore, in order to solve such a problem, Patent Document 1 provides an underground beam immediately above the junction and branching portion of the tunnel, and an underground anchor between the underground beam and the junction and branching portion of the tunnel. It is proposed to stabilize the tunnel structure and eliminate the central pillar.

However, the tunnel junction / branch structure proposed in Patent Document 1 has the following technical problems.
JP 2003-138898 A

  That is, in the structure proposed in Patent Document 1, an underground beam is provided immediately above the junction and branching portion of the tunnel, and an underground anchor is provided between the underground beam and the junction and branching portion of the tunnel. When constructing the middle beam, construction from the ground side is required, and if it is not a place where construction of the underground beam is possible, it is not possible to provide a junction or branching section. There were restrictions.

  The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a tunnel junction and branch structure that can be provided without being restricted by the installation location. There is.

  In order to achieve the above-mentioned object, the present invention provides a joining and branching structure of a shield tunnel provided with a connecting portion that communicates between a pair of shield tunnels formed in parallel at a predetermined interval. A PC steel wire that is arranged so as to circulate between a pair of shield tunnels and the connecting portion and that is fixed by introducing tension is arranged.

  Further, the present invention provides a shield tunnel merging / branching structure in which a connecting portion communicating between a pair of shield tunnels formed in parallel at a predetermined interval is provided between the pair of shield tunnels. Tie rods connected in the horizontal direction were provided in parallel.

  Further, according to the present invention, in a joining and branching structure of a shield tunnel provided with a connecting portion communicating between a pair of shield tunnels formed in parallel at a predetermined interval, each section of the shield tunnel is The thickness is gradually increased as the distance from the connecting portion increases.

  Further, according to the present invention, there is provided a shield tunnel merging / branching structure in which a connecting portion communicating between a pair of shield tunnels formed in parallel at a predetermined interval is provided, wherein the connecting portion includes the shield A flat plate upper plate and a bottom plate that lock both ends of each segment of the tunnel are provided, and the upper plate and the segment have a locking structure between inclined surfaces, and the segment end portion tends to move downward. Then, the upper plate moves upward, and the reaction force is obtained by the ground on which the upper plate contacts.

  According to the joining and branching structure of the tunnel configured as described above, the arrangement of PC steel wires or tie rods, the thickening of the cross section that can be performed from the inside of the tunnel, and the locking structure between the inclined surfaces of the upper plate and the segment end Since each tunnel structure can be stabilized, the middle pillar of the junction or branching portion can be removed.

  Furthermore, the present invention provides a shield tunnel merging / branching structure in which a connecting portion communicating between a pair of shield tunnels formed in parallel at a predetermined interval is provided between the pair of shield tunnels and the pair of shield tunnels. A PC steel wire that is arranged so as to circulate between the connecting portions and that is fixed by introducing a tension force; a tie rod that connects the pair of shield tunnels in a horizontal direction is provided in parallel; Each cross section of the shield tunnel is formed such that the thickness gradually increases as the distance from the connection portion increases. The tie rods connecting the pair of shield tunnels are provided in parallel. Each segment has a flat plate upper plate and a bottom plate that lock both ends, and the upper plate and the segment have a locking structure between inclined surfaces. A plurality of protrusions projecting outward from the vicinity of the connecting portion and / or the vicinity of the connecting portion of the segment when the segment end moves downward. Any two or more of the ground anchors can be arbitrarily combined.

  According to the joining and branching structure of the tunnel according to the present invention, the thickening of the cross section that can be performed from the inside of the tunnel, the arrangement of the PC steel wire or the tie rod, the locking structure between the inclined surfaces of the upper plate and the segment end, the ground anchor Since the tunnel structure can be stabilized by installing, the middle pillar of the junction or branching portion can be removed.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

  1 to 6 show a first embodiment of a junction and branch structure of a tunnel according to the present invention. The tunnel junction / branch structure shown in these figures is constructed by constructing a pair of first shield tunnel 10 and second shield tunnel 12 having a substantially circular cross section in the ground by a shield method, and joining these at a predetermined location. At the same time, after a predetermined merging length, it is branched again.

  The first and second shield tunnels 10 and 12 are constructed as a tunnel by assembling the segments 14 and 16 in an annular shape. When forming the junction, the tunnels 10 and 12 They are arranged in parallel at intervals.

  Between the shield tunnels 10 and 12 arranged in parallel, a part of the opposing segments 14 and 16 is removed to form openings 18 and 20 on the side surfaces, respectively. After excavating the natural ground, the connection part 22 which connects between the tunnels 10 and 12 is formed.

  In the case of the present embodiment, the connecting portion 22 is extended in the tunnel axial direction corresponding to the length of the junction or branching portion of the tunnel to be constructed, and has a generally flat plate-like upper plate 24, bottom plate 26, and These upper and bottom slabs 24 and 26 are engaged with the edges of the openings 18 and 20 of the segments 14 and 16 at predetermined intervals in the vertical direction.

  In this case, the upper plate 24 is locked to the edges of the openings 18 and 20 by a predetermined locking structure between the inclined surfaces. In addition, the locking structure of the connection part 22 does not need to be restricted to such locking of inclined surfaces, For example, a normal butting structure may be sufficient.

  Moreover, in the case of a present Example, the PC steel wire 28 is installed between the pair of shield tunnels 10 and 12 and the connection part 22 so that these may be circulated in the continuous state.

  A plurality of such PC steel wires 28 are provided at predetermined intervals along the axial direction of the tunnels 10 and 12, and the end portions of the PC steel wires 28 are connected to the segments 14, 16 or the tunnels 10 and 12. Fixing is appropriately performed on the connection portion 22 and the bottom plates 24 and 26 in a state where tension is introduced.

  In this case, the fixing positions of both ends of the PC steel wire 28 can be arbitrarily set, and the fixing positions of the plurality of PC steel wires 28 can be shifted so as not to be the same position in the tunnel axis direction.

  According to the joining and branching structure of the tunnel configured as described above, the PC steel wire 28 is arranged so as to circulate between the pair of shield tunnels 10 and 12 and the connecting portion 22 and is fixed by introducing tension. Therefore, the prestress introduced into the PC steel material reduces the tensile force generated in the RC cross section and stabilizes the structure of the merge or branching portion.

  For this reason, it is not necessary to provide a middle column at the junction or branching portion, and the installation work of the PC steel wire 28 can be performed from the inside of the tunnels 10 and 12, so that the junction or branching portion of the junction or branching portion is provided as in the case of providing an underground beam. There are no restrictions on the installation location.

  2 to 6 show an example of a method for constructing the junction and branch structure of the tunnel. When constructing a merge and branch structure, first, as shown in FIG. 2, a pair of first and second shield tunnels 10 and 12 are spaced apart at a predetermined interval at a location where a merge or branch part is constructed. Arranged in parallel.

  Next, as shown in FIG. 3, a chemical solution is injected from the tunnels 10 and 12 to the outer ground, and the opposing portions of the tunnels 10 and 12 are surrounded by half a circumference so that the ground improvement area 30 and a temporary support 32 for preventing deformation is installed in each of the tunnels 10 and 12.

  Next, as shown in FIG. 4, a part of the segments 14, 16 of the tunnels 10, 12 is removed to provide openings 18, 20 within the ground improvement zone 30 located outside the openings 18, 20. The earth and sand are excavated and removed to form the upper plate 24 and the bottom plate 26 of the connecting portion 22, and the tunnels 10 and 12 are communicated laterally.

  Next, as shown in FIG. 5, the PC steel wire 28 is arranged so as to circulate between the shield tunnels 10, 12 and the connecting portion 22. As for the arrangement of the PC steel wire 28, a sheath tube through which the steel wire 28 can be inserted is embedded in advance in the segments 14, 16 and the upper plate 24 and the bottom plate 26.

  When the placement of the PC steel wire 28 is completed, a tension force is introduced into the PC steel wire 28 to fix the ends to the segments 14 and 16, the upper plate 24 and the bottom plate 26. When the fixing of the PC steel wire 28 is completed, as shown in FIG. 6, when the temporary support 32 is removed, the joining and branching structure shown in FIG. 1 is completed.

  7 and 8 show a second embodiment of the junction / branch structure of the tunnel according to the present invention. The same or corresponding parts as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only the feature points will be described below.

  In the joining and branching structure of the tunnels shown in these drawings, as in the first embodiment, between the pair of shield tunnels 10 and 12 formed in parallel at a predetermined interval, a connecting portion 22 that communicates between the two is provided. Is provided.

  In the case of the present embodiment, in place of the PC steel wire 28 of the first embodiment, a predetermined interval is set in the vertical direction so that the tie rods 34 connecting the pair of shield tunnels 10 and 12 in the horizontal direction are parallel to each other. It is provided apart.

  The pair of tie rods 34 are arranged on the same vertical plane, and each tie rod 34 is located near the upper and lower ends of the tunnels 10 and 12, one end side is fixedly fixed to the segment 14 of one tunnel 10, and the other end side is fixed. It is fixedly fixed to the segment 16 of the other tunnel 12.

  A plurality of such tie rods 34 are provided at predetermined intervals along the tunnel axis direction. According to the joining / branching structure of the tunnel configured as described above, by installing the tie rod 34, the tensile force generated in the cross section of the branching / merging part is reduced, and the structure of the joining / branching part is stabilized.

  For this reason, it is not necessary to provide a middle pillar at the junction or branching portion, and the installation work of the tie rod 34 can be performed from the inside of the tunnels 10 and 12, so that the installation location of the junction or branching portion is provided as in the case of providing an underground beam. Is no longer restricted.

  FIG. 8 shows a main part of the process when the tie rod 34 is installed. When the tie rod 34 is installed at the junction or branching part, the processes of FIGS. 2 to 4 described in the first embodiment are sequentially performed. Then, it replaces with installation of the PC steel wire 28 of FIG. 6, and the tie rod 34 is installed and the support work 32 is removed.

  FIG. 9 shows a third embodiment of the junction / branch structure of the tunnel according to the present invention. The same or corresponding parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only the feature points will be described.

  In the junction and branch structure of the tunnel shown in this figure, as in the first embodiment, between the pair of shield tunnels 10 and 12 formed in parallel at a predetermined interval, a connecting portion 22 that communicates between the two is provided. Provide.

  In the case of the present embodiment, instead of installing the PC steel wire 28 of the first embodiment, the thicknesses of the segments 14a and 16a installed at the junction or branch of the tunnels 10 and 12 are made different from those used at other portions. Yes.

  That is, in the case of the present embodiment, the thickness of the segments 14a and 16a gradually increases as the distance from the connecting portion 22 increases, and the thickness is at both ends of the horizontal cross section passing through the centers of the tunnels 10 and 12. Try to be the largest.

  According to the joining / branching structure of the tunnel configured as described above, the thickness of the segments 14a and 16a is increased at the branching or joining part, so that the cross-sectional rigidity of this part is increased. Is stable.

  For this reason, it is not necessary to provide a middle pillar at the junction or branching portion, and the installation work of the tie rod 34 can be performed from the inside of the tunnels 10 and 12, so that the installation location of the junction or branching portion is provided as in the case of providing an underground beam. Is no longer restricted.

  FIG. 10 shows a fourth embodiment of the junction and branch structure of the tunnel according to the present invention. The same or corresponding parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only the feature points will be described.

  In the junction and branch structure of the tunnel shown in this figure, as in the first embodiment, between the pair of shield tunnels 10 and 12 formed in parallel at a predetermined interval, a connecting portion 22 that communicates between the two is provided. Provide.

  In the case of the present embodiment, the connecting portion 22 includes a flat plate upper plate 24 and a bottom plate 26 that are engaged with the segments 14 and 16 of the shield tunnels 10 and 12 at both ends. The upper plate 24 and the bottom plate 26 and the segments 14 and 16 have a locking structure between inclined surfaces.

  In this locking structure, both end surfaces of the upper plate 24 in the width direction (transverse direction of the tunnel) are downward inclined surfaces whose lower end side is located inward of the upper end side, and the segments 14 and 16 that are in contact with the inclined surfaces. As for the surface of the upper end side of each opening part 18 and 20, the lower end side is an uphill inclined surface located in the outward rather than the upper end side.

  Further, both end surfaces of the bottom plate 26 are upward inclined surfaces in which the upper end side is located inward of the lower end side, and the surfaces on the lower end side of the openings 18 and 20 of the segments 14 and 16 that are in contact with the upper end side are The upper end side is a downward inclined surface located outward from the lower end side.

  According to such a locking structure between the inclined surfaces, as shown in FIG. 10, when the upper ends of the openings 18 and 20 try to move downward, the both ends of the upper plate 24 are moved by the locking structure between the inclined surfaces. Try to move upward. In this case, since the upper surface of the upper plate 24 is in contact with the natural ground, the movement reaction force at this time is secured by the natural mountain in contact with the upper surface of the upper plate 24, and the tunnel structure can be stabilized.

  When the tunnel structure is stabilized, it is not necessary to provide a middle pillar at the junction or branching portion, as in the above-described embodiment, and the installation work of the connecting portion 22 is performed as shown in FIGS. Since it can be performed from the inside, there is no restriction on the location of the junction or branching portion as in the case where an underground beam is provided.

  FIG. 11 shows a fifth embodiment of the junction / branch structure of the tunnel according to the present invention. The same or corresponding parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only the feature points will be described.

  In the joining and branching structure of the tunnel shown in this figure, as in each embodiment, a connecting portion 22 is provided between a pair of shield tunnels 10 and 12 that are formed in parallel with a predetermined interval therebetween. Provide.

  In this embodiment, the grant anchor 36 is provided in addition to the locking structure between the inclined surfaces of the upper and bottom plates 24 and 26 of the connecting portion 22 and the open ends of the segments 14 and 16 shown in the fourth embodiment. It is installed.

  In the case of the present embodiment, the ground anchor 36 is extended toward the ground in the vertical direction so as to penetrate the segments 14 and 18 in the vicinity of the openings 18 and 20 from the inside. Is fixed to the ground and the base end side is fixed to the segments 14 and 18.

  In the case of the present embodiment, the ground anchor 36 provided from one tunnel 10 and the ground anchor 36 provided from the other tunnel 12 are not on the same plane, and are provided at a distance from each other in the tunnel axis direction. When the tip end side of each ground anchor 36 is viewed from the front side of the tunnel, they are arranged so as to cross each other.

  A plurality of such ground anchors 36 are arranged at predetermined intervals along the tunnel axis direction in the joining or branching portion to be constructed. In addition, the ground anchor 36 having such a configuration can be provided not only in the segments 14 and 18 in the vicinity of the openings 18 and 20 but also from the upper plate 24 and the bottom plate 26 of the connecting portion 22.

  Further, the extending direction is not necessarily limited to the cross form shown in FIG. 11. For example, the ground anchors 36 extending from the tunnels 10 and 12 may be installed in parallel to each other.

  According to the joining and branching structure of the tunnel configured as described above, in addition to the locking structure between the inclined surfaces of the upper part of the connecting portion 22, the bottom slabs 24 and 26, and the open ends of the segments 14 and 16, the grant Since the anchor 36 is installed, the tunnel structure at the junction or branch is further stabilized.

  FIG. 12 shows a sixth embodiment of the junction / branch structure of the tunnel according to the present invention. The same or corresponding parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only the feature points will be described.

  In the joining and branching structure of the tunnel shown in this figure, as in each embodiment, a connecting portion 22 is provided between a pair of shield tunnels 10 and 12 that are formed in parallel with a predetermined interval therebetween. Provide.

  In the case of the present embodiment, in addition to the locking structure of the inclined surfaces of the upper and bottom plates 24, 26 and the open ends of the segments 14, 16 shown in the fourth embodiment, The PC steel wire 28 shown in Example 1 and the tie rod 34 shown in Example 2 are used in combination.

  In the case of this embodiment, in particular, when a PC steel wire 28 is installed and tension is introduced and fixed thereto, the openings 18 and 20 of the tunnels 10 and 12 are intended to be closed. Against this acting force, the locking structure between the inclined surfaces of the upper and bottom plates 24 and 26 of the connecting portion 22 and the open ends of the segments 14 and 16 shown in the fourth embodiment. Therefore, the ground reaction force acts on the upper surface of the upper plate 24 and the lower surface of the bottom plate 26, so that the tunnel structure of the merged or branched portion is further stabilized as compared with the case of using alone.

  FIG. 13 shows a seventh embodiment of the junction / branch structure of the tunnel according to the present invention. The same or corresponding parts as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only the feature points will be described.

  In the joining and branching structure of the tunnel shown in this figure, as in each embodiment, a connecting portion 22 is provided between a pair of shield tunnels 10 and 12 that are formed in parallel with a predetermined interval therebetween. Provide.

  In the case of the present embodiment, in addition to the locking structure of the inclined surfaces of the upper and bottom plates 24, 26 and the open ends of the segments 14, 16 shown in the fourth embodiment, The PC steel wire 28 shown in Example 1 and the ground anchor 36a shown in Example 5 are used in combination.

  In the case of the present embodiment, the grant anchor 36a extends from the inside of the connecting portion 22 through the upper plate 24 and the bottom plate 26 so as to extend in the vertical direction, and is arranged so that the two are parallel to each other. Has been. The same effect as that of the above embodiment can be obtained even in the junction and branch structure of the tunnel configured as described above.

  FIG. 14 shows an eighth embodiment of the junction / branch structure of the tunnel according to the present invention. The same or corresponding parts as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted. Only the feature points will be described.

  In the joining and branching structure of the tunnel shown in this figure, as in each embodiment, a connecting portion 22 is provided between a pair of shield tunnels 10 and 12 that are formed in parallel with a predetermined interval therebetween. Provide.

  In the case of the present embodiment, in addition to the locking structure of the inclined surfaces of the upper and bottom plates 24, 26 and the open ends of the segments 14, 16 shown in the fourth embodiment, The PC steel wire 28 shown in Example 1 and the thickening means for the segments 14a and 16a shown in Example 3 are used in combination. The same effect as that of the above embodiment can be obtained even in the junction and branch structure of the tunnel configured as described above.

  The tunnel junction / branch structure according to the present invention does not need to be provided with a middle pillar, so it can be effectively used when constructing a junction or branch of a road tunnel or when used as a crossover part of a subway. it can.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional explanatory view showing Example 1 of a junction / branch structure of a tunnel according to the present invention. FIG. 2 is a cross-sectional explanatory diagram of an initial process when the joining / branching structure of FIG. FIG. 3 is an explanatory cross-sectional view of a process performed subsequent to FIG. 2. FIG. 4 is a cross-sectional explanatory diagram of a process performed subsequent to FIG. 3. FIG. 5 is a cross-sectional explanatory diagram of a process performed subsequent to FIG. 4. FIG. 6 is an explanatory cross-sectional view of a process performed subsequent to FIG. 5. It is sectional explanatory drawing which shows Example 2 of the confluence | merging and branching structure of the tunnel concerning this invention. FIG. 8 is an explanatory cross-sectional view of a main part when a joining / branching structure of Example 2 shown in FIG. 7 is constructed. It is sectional explanatory drawing which shows Example 3 of the confluence | merging and branching structure of the tunnel concerning this invention. It is sectional explanatory drawing which shows Example 4 of the confluence | merging and branching structure of the tunnel concerning this invention. It is sectional explanatory drawing which shows Example 5 of the confluence | merging and branching structure of the tunnel concerning this invention. It is sectional explanatory drawing which shows Example 6 of the confluence | merging and branching structure of the tunnel concerning this invention. It is sectional explanatory drawing which shows Example 7 of the confluence | merging and branching structure of the tunnel concerning this invention. It is sectional explanatory drawing which shows Example 8 of the confluence | merging and branching structure of the tunnel concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 1st shield tunnel 12 2nd shield tunnel 14, 14a Segment 16, 16a Segment 18, 20 Opening part 22 Connection part 24 Upper plate 26 Bottom plate 28 PC steel wire 30 Ground improvement area

Claims (5)

In a joining and branching structure of a shield tunnel provided with a connecting portion that communicates between a pair of shield tunnels formed in parallel at a predetermined interval,
A tunnel joining / branching structure characterized in that a PC steel wire, which is arranged so as to circulate between the pair of shield tunnels and the connecting portion and which is fixed by introducing tension, is arranged. In a joining and branching structure of a shield tunnel provided with a connecting portion that communicates between a pair of shield tunnels formed in parallel at a predetermined interval,
A merging / branching structure of shield tunnels, wherein tie rods are provided in parallel to connect the pair of shield tunnels in a horizontal direction. In a joining and branching structure of a shield tunnel provided with a connecting portion that communicates between a pair of shield tunnels formed in parallel at a predetermined interval,
Each of the cross sections of the shield tunnel is formed such that the thickness gradually increases as the distance from the connecting portion increases. In a joining and branching structure of a shield tunnel provided with a connecting portion that communicates between a pair of shield tunnels formed in parallel at a predetermined interval,
The connecting portion includes a plate-like upper plate and a bottom plate that locks both ends to each segment of the shield tunnel,
The upper plate and the segment have a locking structure between inclined surfaces, and when the segment end portion moves downward, the upper plate moves upward, and the upper plate contacts the upper plate. Shield tunnel merging / branching structure characterized by reaction force. In a joining and branching structure of a shield tunnel provided with a connecting portion that communicates between a pair of shield tunnels formed in parallel at a predetermined interval,
Arranging a PC steel wire arranged so as to circulate between the pair of shield tunnels and the connecting portion, and to be fixed by introducing tension;
Providing parallel tie rods that connect the pair of shield tunnels in a horizontal direction;
Each cross section of the shield tunnel is formed such that the thickness gradually increases as the distance from the connection portion increases.
The connecting portion includes a flat plate upper plate and a bottom plate that lock both ends to each segment of the shield tunnel, and the upper plate and the segment have a locking structure between inclined surfaces, and the segment end When the portion moves downward, the upper plate moves upward.
Installing a plurality of ground anchors projecting outward from the vicinity of the connecting portion and / or the vicinity of the connecting portion of the segment;
A tunnel merging / branching structure characterized by any combination of any two of the above.

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