JP2020012370A - Outer frame and outer frame construction method - Google Patents

Abstract

To construct a strong outer frame.SOLUTION: An outer frame 12 of an underground structure 1 comprises: a leading shield tunnel 13 having a leading outer shell 13A; a trailing shield tunnel 14 having a trailing outer shell 14A superimposed on the leading shield tunnel 13 with the leading outer shell 13A of the leading shield tunnel 13 being cut; a first concrete cast into the leading shield tunnel 13 and the trailing shield tunnel 14 and integrated through an opening 34 formed in a part of the trailing outer shell 14A of the trailing shield tunnel 14; a support unit 40 having a shape steel, installed in the leading shield tunnel 13; and a second concrete disposed between the leading outer shell 13A and the first concrete.SELECTED DRAWING: Figure 25

Description

  The present invention relates to an outer frame of an underground structure and a method of constructing an outer frame of an underground structure.

  Patent Literatures 1 and 2 disclose a method of constructing a large-section tunnel in a confluence area of a main line shield tunnel and a branch line shield tunnel. In this method, first, after constructing a leading shield tunnel, a trailing shield tunnel is constructed while cutting a part of the leading shield tunnel. Next, an outer frame constructed by connecting the preceding shield tunnel and the following shield tunnel is constructed. In constructing the outer shell, concrete is cast in the preceding shield tunnel before constructing the succeeding shield tunnel, and concrete is cast in the succeeding shield tunnel after the succeeding shield tunnel is constructed. Thus, the concrete cast in the preceding shield tunnel and the concrete cast in the following shield tunnel are connected to form an outer frame. Then, the underground cavity is formed by excavating the inner peripheral area of the outer shell.

JP-A-2005-105513 JP-A-2006-153601

  In the methods described in Patent Literatures 1 and 2, concrete cast in the preceding shield tunnel and concrete cast in the subsequent shield tunnel are cast at different timings. A joint (interface) of concrete is formed between the shield tunnel. The joint is likely to be a path of groundwater or the like, and causes a decrease in durability. Therefore, it is necessary to perform a process for improving water tightness and durability at the joint. For this reason, there is a problem that as the number of joints increases, the number of man-hours and man-hours increase.

  Therefore, an object of the present invention is to provide a solid shell and a method for constructing a shell that can build a solid shell.

  An outer shell building method according to the present invention is an outer shell building method for building an outer shell of an underground structure, comprising: a preceding shield tunnel building step of building a preceding shield tunnel having a preceding shell; Shield tunnel construction process of constructing a trailing shield tunnel having a trailing outer shell while cutting the part, and a hull skeleton constructing a hull of concrete cast in the leading shield tunnel and the trailing shield tunnel In the preceding shield tunnel construction step, the preceding shield tunnel construction step cuts the outer shell planned area in the preceding outer shell where concrete is to be poured in the outer shell construction step in the subsequent shield tunnel construction step. Partition walls to be divided into a side portion including the planned cutting region and a central portion not including the planned cutting region, and a column supporting the partition walls, Along with the installation, a cuttable filler that can be cut in the subsequent shield tunnel construction process is cast in the area to be cut, which is divided by the partition walls, in the outer shell planned area. The trailing outer shell of the leading shield tunnel and the cuttable filler are cut to construct the trailing shield tunnel, and in the outer shell building process, a part of the trailing shell of the trailing shield tunnel, cutting inside the leading shield tunnel The possible filling material and the partition are removed, and concrete is cast into the outer shield body planned area of the preceding shield tunnel and the following shield tunnel to be integrated.

  According to this outer shell building method, when a part of the following outer shell, the cuttable filler, and the partition are removed in the outer shell building step, the adjacent shield tunnel and the following shield tunnel communicate with each other. Concrete can be cast into the tunnel and the subsequent shield tunnel to be integrated. This makes it possible to reduce the number of joints formed in the outer skeleton, as compared with a case where the outer skeleton is constructed by casting concrete for each shield tunnel, thereby reducing the number of steps and the cost.

  The support may support the preceding outer shell from the inner peripheral side. In this outer shell building method, in the preceding shield tunnel construction step, since a support for supporting the preceding outer shell from the inner peripheral side is installed in the preceding outer shell of the preceding shield tunnel, the preceding outer shell is formed in the succeeding shield tunnel building step. , It is possible to suppress deformation of the preceding outer shell.

  In the preceding shield tunnel construction step, concrete may be cast in an area between one end of the column and the preceding shell in the preceding shell. In this outer frame construction method, concrete is poured into an area between one end of the column and the preceding shell in the preceding shield tunnel construction process, so that the column is used to increase the rigidity of the preceding shield tunnel and the column is used to construct the preceding shell. It can be supported efficiently.

  In the following shield tunnel construction step, the following shield tunnel may be constructed while cutting a part of the preceding shield tunnel on both sides of the preceding shield tunnel. In this outer shell construction method, in order to construct a subsequent shield tunnel while cutting a part of the preceding shield tunnel on both sides of the preceding shield tunnel, in the outer shell building process, concrete cast into the preceding shield tunnel and its concrete It can be integrated with concrete cast in the following shield tunnels arranged on both sides. Thus, the number of seams formed in the outer frame can be further reduced.

  In the preceding shield tunnel construction step, as a partition wall, a first partition wall that partitions a side portion including one planned cutting region, and a second partition wall that partitions a side portion including the other planned cutting region, are installed, and as pillars A first support supporting the first partition and a second support supporting the second partition may be provided. According to this outer shell building method, a cavity is formed between the first partition supported by the first support and the second partition supported by the second support in the preceding shield tunnel building process. Then, by removing a part of the trailing outer shell, the cuttable filler, and the partition, the leading shield tunnel and the trailing shield tunnel arranged on both sides thereof can be communicated. In addition, it is possible to reduce the amount of the concrete and the cuttable filler that are cast in the preceding shield tunnel construction process.

  The trailing outer shell has a main girder extending in the circumferential direction of the trailing shield tunnel, and a skin plate supported by the main girder to separate the inside and the outside of the trailing outer shell. By removing the shield tunnel, the outer shell planned area in the preceding shield tunnel may communicate with the following shield tunnel. According to this outer shell building method, an opening that connects the outer shell planned area in the preceding shield tunnel and the following shield tunnel can be formed by removing the skin plate of the following outer shell. The concrete cast in the shield tunnel and the concrete cast in the subsequent shield tunnel can be integrated.

  The outer shell according to the present invention is an outer shell of an underground structure, and includes a leading shield tunnel having a leading shell, a trailing shield tunnel overlapping with the leading shield tunnel and having a trailing shell, a leading shield tunnel, The concrete is cast and integrated into the following shield tunnel, and the following shield tunnel is superimposed on the preceding shield tunnel with the preceding shell of the preceding shield tunnel cut. The installed concrete and the concrete cast in the following shield tunnel are integrated through an opening formed in a part of the trailing outer shell of the following shield tunnel. In this outer shell, concrete cast in the preceding shield tunnel and the succeeding shield tunnel stacked on each other are integrated through an opening formed in a part of the trailing outer shell of the following shield tunnel, It is possible to reduce the number of joints formed in the outer skeleton, as compared with the outer skeleton in which concrete is cast for each shield tunnel. Thereby, the man-hour and the construction cost for constructing the shell can be reduced. In addition, a strong outer frame with excellent integration can be constructed.

  According to the present invention, a strong shell can be constructed.

It is a perspective view showing the schematic structure of the underground structure concerning an embodiment. FIG. 2 is a sectional view taken along line II-II shown in FIG. 1. FIG. 3 is a sectional view taken along line III-III shown in FIG. 1. It is a figure which shows the structure of the outer shell of a shield tunnel. FIG. 5 is a sectional view taken along line VV shown in FIG. 4. It is sectional drawing which shows the structure of the part which overlaps with the trailing shield tunnel of a preceding outer shell. It is sectional drawing which shows a part of shell structure. It is a schematic diagram for demonstrating a starting base construction process. FIG. 9 is a sectional view taken along line IX-IX shown in FIG. 8. It is a mimetic diagram for explaining a preceding shield tunnel extension process. It is sectional drawing in the XI-XI line | wire shown in FIG. FIG. 11 is a sectional view taken along line XII-XII shown in FIG. 10. It is sectional drawing for demonstrating the area | region in a preceding shield tunnel. It is sectional drawing for demonstrating the preceding shield tunnel filling process. It is sectional drawing which shows the internal structure of a preceding shield tunnel. It is a perspective view which shows a support unit. It is sectional drawing in the XVII-XVII line | wire shown in FIG. It is sectional drawing in the XVIII-XVIII line shown in FIG. It is sectional drawing for demonstrating arrangement | positioning of a support unit. Sectional drawing which shows the internal structure of the preceding shield tunnel which was cut. It is a schematic diagram for demonstrating the following shield tunnel construction process. FIG. 22 is a sectional view taken along line XXII-XXII shown in FIG. 21. FIG. 22 is a sectional view taken along line XXII-XXIII shown in FIG. 21. It is sectional drawing for demonstrating a shell construction process. It is sectional drawing for demonstrating a shell construction process. It is sectional drawing which shows the state which removed the partition of the support unit. It is sectional drawing for demonstrating a shell construction process. It is sectional drawing for demonstrating a shell construction process. It is a schematic diagram for demonstrating a consistent wall construction process. It is a schematic diagram for explaining an excavation process.

  Hereinafter, with reference to the drawings, a preferred embodiment of a method for constructing an outer frame and an outer frame will be described in detail. In the present embodiment, the outer shell framing method according to the present invention is applied to a main line shield tunnel and a branch line shield tunnel in a confluence area of the main line shield tunnel and the branch line shield tunnel in order to merge the new branch line shield tunnel with the existing main line shield tunnel. It is applied to a method of constructing a large section tunnel surrounding both sides of the tunnel. The outer frame according to the present embodiment is the outer frame of a large-section tunnel constructed by such a method. However, the outer frame building method and the outer frame of the present invention are not limited to such a method for constructing a large-section tunnel and those applied to the large-section tunnel. In all the drawings, the same or corresponding parts are denoted by the same reference symbols.

  First, the underground structure will be described. As shown in FIGS. 1 to 3, the underground structure 1 according to the present embodiment includes both the main line shield tunnel 2 and the branch line shield tunnel 3, which are constructed in a confluence area of the main line shield tunnel 2 and the branch line shield tunnel 3. It is a large section tunnel surrounding. An underground cavity 4 extending in the axial direction of the underground structure 1 is formed inside the underground structure 1, and the underground structure 1 has an outer frame 12 of the underground cavity 4 formed by connecting a plurality of shield tunnels 11. It has.

  The shield tunnel 11 is a tunnel constructed by a known shield excavation method or a shield propulsion method. That is, the shield tunnel 11 excavates underground with a shield machine while assembling a segment serving as a wall of the tunnel behind the shield machine, or excavating the shield machine by obtaining thrust by a propulsion pipe. The tunnel is constructed by assembling the propulsion pipe. That is, the shield tunnel 11 is extended by constructing a tunnel lining body or a tunnel frame by a segment assembled by excavating the shield excavator or a propulsion pipe assembled by excavation. The segment assembled by excavating the shield excavator and the propulsion pipe assembled along with the excavation become the outer shell 11A of the shield tunnel 11. In the underground structure 1, the underground structure 1 is axially extended between one end 1a (upper right end in FIG. 1) and the other end 1b (lower left end in FIG. 1). A plurality of shield tunnels 11 are arranged in the circumferential direction so as to surround both the main line shield tunnel 2 and the branch line shield tunnel 3.

  As shown in FIGS. 4 and 5, the outer shell 11 </ b> A is constructed by a plurality of segment rings in which a plurality of segments 30 are assembled in a ring shape in a circumferential direction and connected in a tunnel axial direction. The segment 30 constituting the outer shell 11A includes a main girder 31, a joint plate 32, and a skin plate 33. The main girder 31 is a member extending in the circumferential direction of the shield tunnel 11 and has a predetermined length in the axial direction of the shield tunnel 11. The main girder 31 is made of, for example, a steel material such as a mold steel, and functions as a structure of the outer shell 11A. The joint plate 32 is a member extending in the axial direction of the shield tunnel 11 and has a predetermined length in the axial direction of the shield tunnel 11. The joint plates 32 of the adjacent segments 30 can be connected to each other, and a plurality of segments 30 are connected in the circumferential direction to form a ring-shaped segment ring closed in the circumferential direction. The joint plate 32 is made of, for example, a plate-like steel material. One or more ribs extending parallel to the joint plate are provided between the joint plates 32. The skin plate 33 is a member forming an outer peripheral surface of the shield tunnel 11. The skin plate 33 is connected to the outer peripheral side of the main girder 31 and separates the inner space side of the shield tunnel 11 from the ground. The main girder 31 of the segment ring and the main girder 31 of the adjacent segment ring can be connected to each other, and a plurality of segment rings are connected in the tunnel axis direction to form the shield tunnel 11. The connection between the main girder 31 adjacent to the main girder 31 and the joint plate 32 and the adjacent joint plate 32 can be performed by, for example, bolting. The skin plate 33 is made of, for example, a curved plate-shaped steel material having an arc-shaped cross section, and functions as a partition separating the outer shell 11A and the ground.

  As shown in FIGS. 1 to 3, the plurality of shield tunnels 11 include a leading shield tunnel 13 which is a part of the plurality of shield tunnels 11 and a remaining shield tunnel among the plurality of shield tunnels 11. And a subsequent shield tunnel 14 which is the tunnel 11. The outer shell 11A of the leading shield tunnel 13 is called a leading shell 13A, and the outer shell 11A of the trailing shield tunnel 14 is called a trailing shell 14A. The leading outer shell 13A and the trailing outer shell 14A are constructed by a plurality of segments 30, as shown in FIGS.

  The leading shield tunnel 13 extends from one end 1a to the other end 1b. The trailing shield tunnel 14 extends from one end 1a to the other end 1b. That is, both ends of the leading shield tunnel 13 and the trailing shield tunnel 14 reach one end 1a and the other end 1b. The following shield tunnel 14 is a shield tunnel that is extended after extending the preceding shield tunnel 13. The trailing shield tunnel 14 is arranged between the adjacent leading shield tunnels 13 and the trailing shield tunnel 14 is superimposed on the leading shield tunnel 13 with the leading shell 13A of the leading shield tunnel 13 being cut. ing. The adjacent leading shield tunnel 13 and trailing shield tunnel 14 overlap in the whole area from one end 1a to the other end 1b. In a portion where the leading shield tunnel 13 and the trailing shield tunnel 14 overlap, the leading shell 13A of the leading shield tunnel 13 is cut off, and the trailing shell 14A of the trailing shield tunnel 14 is formed as shown in FIG. The joint plate 32, the rib and the skin plate 33 are removed from the main girder 31 to form an opening 34.

  Then, the distance between the central axis of the adjacent preceding shield tunnel 13 and the central axis of the following shielding tunnel 14 becomes narrower from one end 1a to the other end 1b, so that the underground cavity 4 becomes the main shield tunnel 2 and The cross-sectional area of the underground cavity 4 decreases from one end 1a to the other end 1b so as to follow the outer shape of the branch shield tunnel 3. Further, the degree of overlap between the adjacent preceding shield tunnel 13 and the succeeding shield tunnel 14 is increased such that the cross-sectional area of the underground cavity 4 decreases from one end 1a to the other end 1b.

  The trailing shield tunnel 14 has a first trailing shield tunnel 141 extending toward the other end 1b and a second trailing tunnel extending between the tip of the first trailing shield tunnel 141 and the other end 1b. And a row shield tunnel 142. The first trailing shield tunnel 141 is a shield tunnel having the same diameter as the leading shield tunnel 13, and the second trailing shield tunnel 142 is a shield tunnel having a smaller diameter than the first trailing shield tunnel 141. The first trailing shield tunnel 141 extends from one end 1a to the other end 1b, and the second trailing shield tunnel 142 extends from the tip of the first trailing shield tunnel 141 to the other end 1b. Stretched. For this reason, in one trailing shield tunnel 14, a portion on one end 1a side becomes a first trailing shield tunnel 141 having a large diameter, and a portion on the other end 1b side has a small diameter second trailing shield tunnel. 142.

  As described above, the distance between the adjacent leading shield tunnels 13 is smaller on the other end 1b side than on the one end 1a side, so that the trailing shield tunnel is provided in the entire region from the one end 1a to the other end 1b. If the tunnels 14 have the same diameter, the overlapping amount of the leading shield tunnel 13 and the trailing shield tunnel 14 becomes excessive. Therefore, on one end 1a side, the trailing shield tunnel 14 is a large diameter first trailing shield tunnel 141, and on the other end 1b side, the trailing shield tunnel 14 is a small diameter second trailing shield tunnel 142. Thus, the amount of overlap between the leading shield tunnel 13 and the trailing shield tunnel 14 is reduced, and the amount of cutting of the leading shield tunnel 13 when the trailing shield tunnel 14 is constructed is reduced.

  More specifically, the shield tunnel 11 is constituted by a total of 36 tunnels including 18 preceding shield tunnels 13 and 18 following shield tunnels 14. That is, the number of the leading shield tunnel 13 and the number of the trailing shield tunnel 14 are the same. The underground structure 1 is divided into two regions, a first region A1 and a second region A2, from one end 1a of the underground structure 1 to the other end 1b. The leading shield tunnel 13 has the same diameter in the first area A1 and the second area A2. The trailing shield tunnel 14 is a first trailing shield tunnel 141 having a large diameter in the first area A1, and a second trailing shield tunnel 142 having a small diameter in the second area A2. The leading shield tunnel 13 and the trailing shield tunnel 14 are alternately arranged, and the trailing shield tunnel 14 is located between the neighboring leading shield tunnels 13.

  As shown in FIG. 1 to FIG. 3 and FIG. 7, the outer frame 12 is a substantially arc-shaped frame that forms the outer shell of the underground cavity 4. The outer frame 12 connects adjacent shield tunnels 11. Specifically, the outer frame 12 is made of reinforced concrete placed in the adjacent preceding shield tunnel 13 and following shield tunnel 14. The reinforced concrete cast in the leading shield tunnel 13 and the reinforced concrete cast in the trailing shield tunnel 14 correspond to the opening 34 formed in a part of the trailing outer shell 14A of the trailing shield tunnel 14 (FIG. 6). Ref.).

  As shown in FIGS. 1 to 3, at one end 1 a of the underground structure 1, a one-side wall 15 that seals (stops water) one side surface of the outer frame 12 is constructed. On the other end 1b of the housing 1, a wall 16 for sealing (water-stopping) the other side surface of the outer frame 12 is constructed.

  Then, by excavating and removing part or all of the inner and outer lands of the outer frame 12 sandwiched between the one side wall 15 and the other side wall 16, the underground cavity 4 is formed inside the underground structure 1. Are formed.

  Next, a method for constructing the above-described underground structure 1 will be described. The underground structure construction method according to the present embodiment includes a starting base construction step (S1), a preceding shield tunnel construction step (S2) for constructing a preceding shield tunnel 13 having a preceding outer shell 13A, and a method of constructing the preceding shield tunnel 13. A trailing shield tunnel construction step (S3) for constructing a trailing shield tunnel 14 having a trailing outer shell 14A while cutting a part, and placing concrete in the leading shield tunnel 13 and trailing shield tunnel 14 An outer shell building step (S4) for building the outer shell body 12 is performed, a wall forming step (S5), and an excavation step (S6).

  In the starting base construction step (S1), as shown in FIGS. 8 and 9, a starting base 21 for extending the shield tunnel 11 is constructed. The starting base 21 extends from the branch shield tunnel 3 to the radially outer peripheral side of the branch shield tunnel 3, and extends circumferentially from the start well 22 so as to surround both the main line shield tunnel 2 and the branch shield tunnel 3. A circumferential shield tunnel 23. The starting port 22 can be constructed by a known shield machine, and the circumferential shield tunnel 23 can be constructed by a known shield machine.

  In the preceding shield tunnel construction step (S2), as shown in FIGS. 1 and 10, one end 1a and the other end 1b of an underground structure planned area (not shown), which is an area where the underground structure 1 is to be constructed. In between, a plurality of preceding shield tunnels 13 extending in the axial direction are constructed in the circumferential direction. The one end 1a and the other end 1b of the planned underground structure area are the same as the one end 1a and the other end 1b of the underground structure 1.

  If the adjacent preceding shield tunnels 13 have been constructed, the subsequent shield tunnel construction step (S3) is started before the extension of all the preceding shield tunnels 13 is completed, and the adjacent preceding shield tunnels being constructed are started. A trailing shield tunnel 14 may extend between the tunnels 13.

  In the preceding shield tunnel construction step (S2), a preceding shield tunnel extending step (S21) and a preceding shield tunnel filling step (S22) are performed.

  In the preceding shield tunnel extending step (S21), as shown in FIGS. 10 to 12, the preceding shield tunnel 13 is extended from the starting base 21 constructed on one end 1a to the other end 1b. Specifically, in the preceding shield tunnel extending step (S21), the 18 preceding shield tunnels 13 are extended from the starting base 21 constructed on one end 1a to the other end 1b. At this time, the adjacent preceding shield tunnels 13 are not extended at the same time, but one of the adjacent preceding shield tunnels 13 is extended first and then the other preceding shield tunnel 13 is extended. Stretching is preferred. It is preferable to use two or more shield excavators for excavation of the preceding shield tunnel 13. By using two or more shield excavators, a plurality of preceding shield tunnels 13 can be extended in parallel.

  Further, in the leading shield tunnel extending step (S21), the plurality of leading shield tunnels 13 are extended such that the center axes of the neighboring leading shield tunnels 13 become closer from one end 1a to the other end 1b. I do.

  Here, the leading shield tunnel 13 needs to include a portion that can be cut by a shield machine or the like that extends the trailing shield tunnel 14. For this reason, in the leading outer shell 13A of the leading shield tunnel 13, at least a segment or a propulsion pipe of a part cut by the extension of the trailing shield tunnel 14 is cuttable. As the cutable segment or the propulsion tube, for example, a cuttable segment or a cutable propulsion tube made of a fiber reinforced resin as described in Patent Document 1, Patent Document 2, Patent No. 4851133, Patent No. 4939803, etc. Used.

  In the preceding shield tunnel filling step (S22), the inside of the preceding shield tunnel 13 is filled so that the shield machine that extends the following shield tunnel 14 can excavate while overlapping the preceding shield tunnel 13.

  Here, as shown in FIG. 13, the regions to be cut in the following shield tunnel construction step (S3) of the preceding shield tunnel 13 are referred to as the planned cutting region 13E and the planned cutting region 13F. The planned cutting region 13E and the planned cutting region 13F are formed on both sides of the preceding shield tunnel 13. Of the regions in the preceding outer shell 13A, a region where concrete is poured in the outer shell building step (S4) is defined as an outer shell scheduled region 13B. One end of the outer shell planned region 13B overlaps with the planned cutting region 13E, and the other end of the outer shell planned region 13B overlaps with the planned cutting region 13F. Of the region in the preceding outer shell 13A, the region other than the planned cutting region 13E, the planned cutting region 13E, and the planned shell structure region 13B is located on the inner peripheral side of the shell structure 12 with respect to the planned shell region 13B. The region is defined as an inner peripheral region 13C. Further, among the regions in the preceding outer shell 13A, the regions other than the planned cutting region 13E, the planned cutting region 13E, and the planned shell structure region 13B, which are located on the outer peripheral side of the shell structure 12 with respect to the planned shell region 13B. The region to be performed is defined as an outer peripheral side region 13D.

  As shown in FIGS. 13 to 15, in the preceding shield tunnel filling step (S22), as the filling inside the preceding shield tunnel 13, the support unit 40 is arranged, and concrete and a cuttable filler are poured (filled). I do.

  The support unit 40 is arranged at the center part in the radial direction of the preceding shield tunnel and in the outer shell scheduled region 13B. The configuration of the support unit 40 will be described later.

  Concrete is cast into the concrete casting area 50A and the concrete casting area 50B. The concrete placing area 50A is an area in the inner peripheral side area 13C, and is an area excluding the planned cutting area 13E, the planned cutting area 13E, and the planned outer shell body area 13B. The concrete placing area 50B is an area inside the outer peripheral side area 13D, and is an area excluding the scheduled cutting area 13E, the scheduled cutting area 13E, and the outer shell planned area 13B. The concrete placement areas 50A and 50B are set excluding the areas to be cut 13E and 13F so that concrete is not cut when excavating the trailing shield tunnel 14 (the trailing outer shell 14A). That is, concrete is not cast near the planned cutting regions 13E and 13F.

  The cuttable filler is cast into the cuttable filler region 51A and the cuttable filler region 51B. The cuttable filler region 51A is a region including the planned cutting region 13E, and is a region surrounded by the preceding outer shell 13A, the support unit 40, and the concrete placing regions 50A and 50B. The cuttable filler region 51B is a region including the planned cutting region 13F, and is a region surrounded by the preceding outer shell 13A, the support unit 40, and the concrete placing regions 50A and 50B. The cuttable filler regions 51A and 51B are regions to be cut (cut) 13E, which are regions in which excavation (cutting) is planned in order to allow an excavation error when excavating the following shield tunnel 14 (the following outer shell 14A). , 13F.

  By the way, as shown in FIG. 20, when the preceding shield tunnel 13 is cut in the succeeding shield tunnel construction step (S3), the main girder 31 supporting the preceding outer shell 13A (see FIGS. 4 and 5). Is also cut to separate the leading shell 13A into a first leading shell 13AA and a second leading shell 13AB. Further, no concrete is cast in the outer shell planned region 13B. For this reason, the main girder 31 cannot support the earth pressure acting in the direction in which the first leading outer shell 13AA and the second leading outer shell 13AB face each other. Therefore, by arranging the support unit 40 in the outer shell scheduled region 13B, when the preceding shield tunnel 13 is cut in the subsequent shield tunnel construction step (S3) of the subsequent step, the load due to earth pressure or impact at the time of cutting. Thus, deformation of the preceding shield tunnel 13 is suppressed.

  As shown in FIGS. 15 to 19, the support unit 40 includes a first partition 41A and a second partition 41B, a first support 42A and a second support 42B, an inner support beam 43A and an outer support support 43B, and , An inner peripheral side shielding plate 44A and an outer peripheral side shielding plate 44B.

  The first partition wall 41A divides the shell body planned region 13B into a side portion 13G including the planned cutting region 13E and a central portion 13J not including the planned cutting region 13E. The second partition wall 41B divides the shell body planned region 13B into a side portion 13H including the planned cutting region 13F and a central portion 13J not including the planned cutting region 13F. The side part 13G divided by the first partition 41A is a region of the first partition 41A opposite to the second partition 41B. The side part 13H divided by the second partition 41B is a region of the second partition 41B opposite to the first partition 41A. The central portion 13J divided by the first partition 41A and the second partition 41B is a region located at the radial center portion of the preceding shield tunnel 13, and is a region between the first partition 41A and the second partition 41B. is there.

  Specifically, the first partition 41A and the second partition 41B are formed of a flat iron plate, and the first partition 41A and the second partition 41B are opposed to each other in the circumferential direction of the outer-frame-body planned region 13B. To be installed in Then, the plurality of first partition walls 41A and the second partition walls 41B are arranged along the axial direction of the preceding shield tunnel 13.

  The first support column 42A supports the first partition wall 41A and also supports the leading outer shell 13A from the inner peripheral side. The second support 42B supports the second partition 41B and also supports the leading outer shell 13A from the inner peripheral side.

  Specifically, the first support 42A and the second support 42B are each made of a steel material such as an H-shaped steel, and the first support 42A and the second support 42B are arranged in parallel in the circumferential direction of the outer frame planned region 13B. Arrange so that The first strut 42A and the second strut 42B are opposed to each other (the concrete casting area 50A) between the first leading outer shell 13AA and the second leading outer shell scheduled part separated in the following shield tunnel construction step (S3). And the concrete placing area 50B).

  The first partition 41A is detachably connected to the first support 42A, and the second partition 41B is detachably connected to the second support 42B. The connection of the first partition 41A and the second partition 41B to the first support 42A and the second support 42B can be performed by, for example, bolting or welding. Then, a plurality of first struts 42A and second struts 42B are arranged along the axial direction of the preceding shield tunnel 13.

  The inner peripheral support girder 43A supports the distal end of the first support 42A and the second support 42B on the concrete placement area 50A side. The outer support girder 43B is the concrete support area of the first support 42A and the second support 42B. Support the 50B side tip.

  Specifically, the inner peripheral side support girder 43A and the outer peripheral side support girder 43B are each made of a steel material such as an H-section steel, and the inner peripheral side support girder 43A and the outer peripheral side support girder 43B are connected to the first column 42A. And it is arrange | positioned corresponding to the 2nd support | pillar 42B so that it may be juxtaposed in the circumferential direction of the outer shell | body planned area 13B. The inner peripheral side support girder 43A is bridged between the first column 42A and the second column 42B along the circumferential direction of the outer frame body planned region 13B, and the concrete column 50A side of the first column 42A and the second column 42B. To the tip of The outer peripheral side support girder 43B is bridged between the first support 42A and the second support 42B along the circumferential direction of the outer shell body planned area 13B, and is provided on the concrete placement area 50B side of the first support 42A and the second support 42B. Connect to the tip.

  The inner peripheral shielding plate 44A shields the support unit 40 on the concrete placing area 50A side. The outer peripheral side shield plate 44B shields the support unit 40 on the concrete placing area 50B side.

  Specifically, the inner-peripheral-side shielding plate 44A and the outer-peripheral-side shielding plate 44B are made of a flat iron plate. They are arranged so as to face each other in the radial direction. The inner peripheral side shielding plate 44A is bridged over the plurality of inner peripheral side support girders 43A along the axial direction of the outer shell planned region 13B, and is joined to the tip of the inner peripheral side support girder 43A on the concrete placing region 50A side. . The outer peripheral side shielding plate 44B is extended over the plurality of outer peripheral side support girders 43B along the axial direction of the outer shell body planned area 13B, and is joined to the tip of the outer peripheral side support girder 43B on the concrete placing area 50B side. Then, a plurality of inner peripheral side shielding plates 44A and outer peripheral side shielding plates 44B are arranged along the axial direction of the preceding shield tunnel 13.

  In the support unit 40 configured as described above, the first support 42A and the second support 42B, the inner peripheral support girder 43A, and the outer support girder 43B form a double-girder frame. Then, inside the support unit 40, an internal space 45 surrounded by the first partition wall 41A and the second partition wall 41B, the inner peripheral side shielding plate 44A, and the outer peripheral side shielding plate 44B is formed. The internal space 45 is the same as the central portion 13J divided by the first partition 41A and the second partition 41B. The first partition 41A, the second partition 41B, the inner peripheral shielding plate 44A, and the outer peripheral shielding plate 44B serve as partitions of the internal space 45 and surround the internal space 45. The concrete and the cuttable filling material do not enter the internal space 45. For this reason, the internal space 45 is hollow.

  In addition, concrete is poured into the concrete placing area 50A in the preceding outer shell 13A between one end of the first support 42A and the second support 42B and the first preceding outer shell 13AA. It is cast in the concrete casting area 50B between the other end of the support 42A and the second support 42B and the second preceding outer shell 13AB. Then, the tip of the first pillar 42A and the second pillar 42B on the concrete placing area 50A side is connected to the concrete placing area 50A of the inner peripheral area 13C via the inner peripheral supporting girder 43A and the inner peripheral shielding plate 44A. The first pillars 42A and the second pillars 42B have their ends on the concrete placing area 50B side through the outer peripheral support beams 43B and the outer peripheral shielding plate 44B. It is connected to the concrete cast in the concrete casting area 50B. Thereby, the first support 42A and the second support 42B support the first partition 41A and the second partition 41B, and the first and second leading shells 13AA and 13AB of the leading shell 13A are inside. Support from the circumferential side.

  The interior of the preceding shield tunnel 13 can be filled, for example, as follows. When the extension of the preceding shield tunnel 13 is completed, the remnants of the shield excavator are left at the tip of the preceding shield tunnel 13, and the recovered material of the shield excavator is collected from the preceding shield tunnel 13 to the starting base 21 at one end 1 a. I do. The collected material of the shield excavator corresponds to, for example, a cutter motor, a shield jack, and electrical components. Of the shield machine, portions having a function of preventing the inflow of earth and sand under the ground, such as a cutter portion and an outer steel shell portion, are left as underground objects. At this time, the inside of the preceding shield tunnel 13 is filled in order from the front end of the preceding shield tunnel 13 toward the one end 1a. Filling the inside of the preceding shield tunnel 13 divides the preceding shield tunnel 13 into a plurality of spans, and constructs a partition wall on one end 1a side of the span to be filled. Then, the support unit 40 is arranged and the concrete and the cuttable filler are poured into the span.

  The arrangement of the support units 40, the order of placing concrete and the cuttable filler, the order of assembling the support units 40, and the like are not particularly limited, and are appropriately set from the viewpoint of workability and the like. Further, some of these steps may be performed simultaneously. In order to place concrete and the cuttable filler in the concrete placement areas 50A, 50B and the cuttable filler areas 51A, 51B, a formwork is appropriately arranged between the support unit 40 and the preceding outer shell 13A. Set up.

  In the following shield tunnel construction step (S3), as shown in FIGS. 1 and 20 to 23, the following shield tunnel 14 is extended from the starting base 21 constructed on one end 1a to the other end 1b. A plurality of trailing shield tunnels 14 extending in the axial direction extend between one end 1a and the other end 1b of an underground structure scheduled area (not shown) which is an area where the underground structure 1 is to be constructed. Build in the direction. Specifically, in the succeeding shield tunnel construction step (S3), 18 trailing shield tunnels 14 are extended from the starting base 21 constructed on one end 1a to the other end 1b in the outer shell planned area. I do. At this time, since the earth and sand on the upper part of the shield tunnel tend to be loosened, it is preferable that the upper part of the shield tunnel is extended in order from the succeeding shield tunnel 14 arranged below so that the upper part is extended by the shield tunnel later. Further, as in the extension of the preceding shield tunnel 13, it is preferable to use two or more shield excavating machines for excavating the following shield tunnel 14. By using two or more shield excavators, a plurality of trailing shield tunnels 14 can be extended in parallel.

  In the following shield tunnel construction step (S3), the center axes of the adjacent subsequent shield tunnels 14 move closer from one end 1a to the other end 1b, and the adjacent shield tunnel 13 The plurality of trailing shield tunnels 14 are extended so that the central axis and the central axis of the trailing shield tunnel 14 approach each other. Thereby, the cross-sectional area of the underground cavity can be reduced from one end 1a to the other end 1b. In the following shield tunnel construction step (S3), one of the preceding shield tunnels 13 is overlapped with the adjacent preceding shield tunnel 13 and the following shield tunnel 14 in the entire area from one end 1a to the other end 1b. The part is cut and the following shield tunnel 14 is extended.

  Here, when a part of the leading shield tunnel 13 is cut, the main girder 31 (see FIGS. 4 and 5) that supports the leading shell 13A is also cut, and the leading shell 13A becomes the first leading shell part 13AA. It is separated from the second preceding outer shell 13AB. However, the first column 42A and the second column 42B of the support unit 40 disposed between the first leading outer shell 13AA and the second leading outer shell 13AB are formed by the inner peripheral supporting beam 43A and the outer peripheral supporting beam 43A. 43A, the inner peripheral side shielding plate 44A and the outer peripheral side shielding plate 44B, and the concrete placed in the concrete placing regions 50A and 50B, the first leading outer shell portion 13AA and the second leading outer shell portion 13AB. Is supported from the inner peripheral side. Therefore, even if a part of the leading shield tunnel 13 is cut in the trailing shield tunnel construction step (S3), the leading shield tunnel 13 does not collapse.

  Then, in the subsequent shield tunnel construction step (S3), as the subsequent shield tunnel 14 of the first area A1, the first subsequent shield tunnel construction step of extending the first subsequent shield tunnel 141 toward the other end 1b. (S31), as the trailing shield tunnel 14 of the second area A2, between the tip of the first trailing shield tunnel 141 and the other end 1b, the second trailing tunnel having a smaller diameter than the first trailing shield tunnel 141. A second succeeding shield tunnel construction step (S32) of extending the row shield tunnel 142 is performed. In the first trailing shield tunnel construction step (S31), the first trailing shield tunnel 141 is extended from one end 1a. In the second trailing shield tunnel construction step (S32), the first trailing shield tunnel 141 The second trailing shield tunnel 142 extends from the tip to the other end 1b. Thereby, one trailing shield tunnel 14 extending from one end 1a to the other end 1b is extended.

  The extension of the first trailing shield tunnel 141 and the second trailing shield tunnel 142 can be performed, for example, by the parent-child shield described in JP-A-2005-194758, JP-A-10-153083, and JP-A-10-096392. By using a machine (parent-child shield excavator), it can be easily performed. That is, in the first trailing shield tunnel construction step (S31), the first trailing shield tunnel 141 is extended by the parent shield machine of the parent-child shield machine, and then the child shield machine is started from the parent-child shield machine. The second trailing shield tunnel 142 is extended from the tip of the first trailing shield tunnel 141 by the machine.

  In the present embodiment, the arrival base (internal cavity) corresponding to the starting base 21 at the one end 1a is not constructed at the other end 1b, but the arrival base 21 at the one end 1a is formed at the other end 1b. When a corresponding arrival base is constructed, the shield machine that has reached the other end 1b may be excavated from the other end 1b toward the one end 1a. In this case, it is not necessary to move the shield machine from the other end 1b to the one end 1a. In addition, when the arrival base corresponding to the starting base 21 of the one end 1a is constructed at the other end 1b, in the second trailing shield tunnel construction step (S32), the arrival base from the arrival base of the other end 1b is The second trailing shield tunnel 142 may extend toward the tip of the first trailing shield tunnel 141. In this case, the extension of the second trailing shield tunnel 142 can be started before the extension of the first trailing shield tunnel 141 ends.

  By the way, as shown in FIG. 24, by the construction of the preceding shield tunnel 13, the support unit 40 is disposed in the outer shell planned area 13 </ b> B inside the preceding shield tunnel 13, and the cuttable filler is cast. Have been. Further, due to the construction of the trailing shield tunnel 14, the adjacent leading shield tunnel 13 and the trailing shield tunnel 14 overlap. In this overlapping portion, the trailing outer shell 14A of the trailing shield tunnel 14 is The tunnel 13 and the following shield tunnel 14 are separated.

  In the outer shell building step (S4), first, as shown in FIG. 25, a part of the trailing outer shell 14A of the trailing shield tunnel 14 is removed, and the leading shield tunnel 13 and the trailing shield tunnel 14 are communicated. Let it. Specifically, as shown in FIG. 5 and FIG. 6, in a portion of the trailing outer shell 14 </ b> A of the trailing shield tunnel 14 that overlaps the leading shield tunnel 13, the main girder 31 is left, and the joint plate 32 is left. Then, the rib and the skin plate 33 are removed. The joint plate 32, the ribs, and the skin plate 33 are removed from the following shield tunnel 14 side. As a result, an opening 34 that connects the leading shield tunnel 13 and the trailing shield tunnel 14 is formed. In the present embodiment, the main girder 31 is left and the joint plate 32 and the rib are removed. However, the main girder 31 may be removed and removed, or the joint plate 32 and the rib may be left. In order to integrate the leading shell 13A and the trailing shell 14A, the skin plate 33 is preferably removed and removed.

  Next, in the outer shell building step (S4), the cuttable filler material cast in the cuttable filler regions 51A and 51B inside the preceding shield tunnel 13 is removed. The removal of the cuttable filler is performed, for example, by cutting a portion of the cuttable filler corresponding to the opening 34 with a cutter of a shield machine. This cutting waste is discharged from the preceding shield tunnel 13 together with the excavated soil from the shield machine.

  Next, in the outer frame building step (S4), as shown in FIGS. 25 and 26, the first partition 41A and the second partition 41B of the support unit 40 are removed. Removal of the first partition 41A and the second partition 41B can be performed by removing the first partition 41A and the second partition 41B from the first support 42A and the second support 42B from the opening 34 side. Since the internal space 45 of the support unit 40 is hollow, by removing the first partition wall 41A and the second partition wall 41B, the outer shell planned region 13B of the preceding shield tunnel 13 becomes the same as the adjacent shield tunnel 14 of the subsequent shield tunnel 14. It is communicated integrally with the internal space. At this time, the first support 42A and the second support 42B are not removed. Since the first support 42A and the second support 42B of the support unit 40 support the first leading outer shell 13AA and the second leading outer shell 13AB from the inner peripheral side, deformation of the leading shield tunnel 13 can be prevented.

  Next, in the outer shell building step (S4), as shown in FIGS. 27 and 28, concrete 62 is cast into the leading shield tunnel 13 and the trailing shield tunnel 14 to be integrated. Specifically, a reinforcing bar 61 is provided in the leading shield tunnel 13 and the trailing shield tunnel 14 so as to extend between the leading shield tunnel 13 and the trailing shield tunnel through the opening 34 (see FIG. 27). Then, concrete 62 is poured into the leading shield tunnel 13 and the trailing shield tunnel 14 (see FIG. 28). In FIG. 28, illustration of the concrete placed in the concrete placement areas 50A and 50B is omitted to make it easier to understand the placement of the concrete 62. As a result, the concrete 62 cast in the preceding shield tunnel 13 and the concrete 62 cast in the subsequent shield tunnel 14 are directly integrated through the opening 34 and are bridged through the opening 34. The rolled-in rebar 61 is rolled up and integrated to form a strong outer frame.

  Then, the concrete 62 (reinforced concrete) thus integrated is cast into all the shield tunnels 11 to form the outer frame 12. At this time, it is preferable that the concrete 62 be poured into all the shield tunnels 11 at once and integrated therewith, since no joint is formed in the circumferential direction of the outer frame 12. However, in consideration of the transportability of the concrete material, the workability of the casting, and the like, all the shield tunnels 11 are divided into a plurality of groups, and concrete 62 is cast and integrated for each of the divided groups. As a result, it is possible to construct the shell 12 having a small number of concrete joints.

  In addition, in the outer frame building construction step (S4), frozen soil is formed around the leading shield tunnel 13 and the trailing shield tunnel 14 by a freezing method or the like so that groundwater or the like does not enter the leading shield tunnel 13 and the trailing shield tunnel 14. It is preferable that the surroundings of the leading shield tunnel 13 and the trailing shield tunnel 14 be frozen and stopped.

  In the joint wall construction step (S5), as shown in FIG. 29, a unilateral joint wall 15 that seals (water-stops) one side surface of the outer skeleton 12 is constructed at one end 1a of the underground structure 1. On the other end 1 b of the underground structure 1, the other side wall 16 for sealing (water stopping) the other side surface of the outer frame 12 is constructed. The one-side wall 15 and the other-side wall 16 are constructed, for example, by freezing the one end 1a and the other end 1b of the underground structure 1 to construct the one-side wall 15 and the other side wall 16. The area to be excavated is excavated and reinforced concrete is poured. Thereby, the one side joint wall 15 and the other side joint wall 16 can be constructed.

  In the excavation step (S6), as shown in FIG. 30, part or all of the inner peripheral region of the outer frame 12 sandwiched between the one side wall 15 and the other side wall 16 is excavated to form the underground cavity 4. Form. That is, by excavating part or all of the inner peripheral region of the outer frame 12 sandwiched between the one side wall 15 and the other side wall 16 and discharging the excavated earth and sand, the inner peripheral side of the outer frame 12 is excavated. A subterranean cavity 4 is formed. The excavated earth and sand is discharged from the main line shield tunnel 2 and the branch line shield tunnel 3.

  As described above, in the present embodiment, in the preceding shield tunnel construction step (S2), the first support 42A and the first support 42A that support the preceding outer shell 13A from the inner circumferential side are provided in the preceding outer shell 13A of the preceding shield tunnel 13. Since the two pillars 42B are provided, even if the preceding outer shell 13A is cut in the subsequent shield tunnel construction step (S3), the deformation of the preceding outer shell 13A can be suppressed. Then, in the outer shell building step (S4), when a part of the trailing outer shell 14A, the cuttable filler, and the first partition 41A and the second partition 41B are removed, the adjacent preceding shield tunnel 13 and subsequent shield tunnel 13 are removed. 14 communicates with the front shield tunnel 13 and the rear shield tunnel 14, and concrete can be cast and integrated. This makes it possible to reduce the number of joints formed in the outer frame 12 as compared with the case where the outer frame is constructed by casting concrete for each shield tunnel, so that the number of steps and the cost can be reduced. Further, a strong outer frame 12 having excellent integrity can be constructed.

  In the preceding shield tunnel construction step, the concrete placing area 50A between one end of the first pillar 42A and the second pillar 42B and the first leading shell 13AA, the first pillar 42A and the second pillar 42B, Since concrete is poured into the concrete placing area 50B between the end portion and the second leading outer shell portion 13AB, the rigidity of the leading shield tunnel 13 is increased while the leading pillar 42A and the second pillar 42B increase the rigidity of the leading shield tunnel 13. The shell 13A can be efficiently supported. In the present embodiment, the first support 42A and the second support 42B support the first leading outer shell 13AA and the second leading outer shell 13AB via concrete, but the first support 42A or the second support The two pillars 42B may directly support the first leading outer shell 13AA or the second leading outer shell 13AB without using concrete.

  Further, in order to construct the succeeding shield tunnel 14 while cutting a part of the preceding shield tunnel 13 on both sides of the preceding shield tunnel 13, concrete cast into the preceding shield tunnel 13 in the outer frame building construction step (S 4). 62 and the concrete 62 cast in the following shield tunnel 14 arranged on both sides thereof can be integrated. Thus, the number of seams formed in the outer frame 12 can be further reduced.

  Further, in the preceding shield tunnel construction step (S2), a cavity is formed in the internal space 45 between the first partition 41A supported by the first support 42A and the second partition 41B supported by the second support 42B. Therefore, by removing a part of the trailing outer shell 14A, the cuttable filler, the first partition 41A and the second partition 41B in the outer shell building step (S4), the outer shield 14 is disposed on the leading shield tunnel 13 and on both sides thereof. Communication with the following shield tunnel 14. In addition, it is possible to reduce the amount of the concrete and the cuttable filler to be cast in the preceding shield tunnel construction step (S2).

  Also, by removing the skin plate 33 of the trailing outer shell 14A, an opening 34 that connects the outer shell planned area 13B in the preceding shield tunnel 13 and the trailing shield tunnel 14 can be formed. A reinforcing bar 61 is disposed between the leading shield tunnel 13 and the trailing shield tunnel 14. Thereby, the concrete 62 cast in the preceding shield tunnel 13 and the concrete 62 cast in the subsequent shield tunnel 14 can be integrated.

  As described above, the preferred embodiments of the present invention have been described, but the present invention is not limited to the above embodiments.

  For example, the following shield tunnel may be stacked only on one side of the preceding shield tunnel. In this case, the concrete that is placed in the preceding shield tunnel and the succeeding shield tunnel that overlap with each other is integrated, and the joint surface is not formed. The leading shield tunnel and the trailing shield tunnel that are adjacent to each other without overlapping each other, for example, by constructing a connection path between the leading shield tunnel and the trailing shield tunnel, and placing reinforced concrete in this connection path, The concrete cast in the leading shield tunnel and the trailing shield tunnel can be connected.

  In addition, the leading shield tunnel and the trailing shield tunnel may not overlap in a part from one end to the other end. Also in this case, for example, by constructing a connecting path between the leading shield tunnel and the trailing shield tunnel and placing reinforced concrete in the connecting path, the connecting tunnel is driven into the leading shield tunnel and the trailing shield tunnel. Can be connected to concrete.

  In addition, the support unit does not necessarily need to include two partitions and columns, but may include at least one partition and columns. In this case, the internal space is not formed in the support unit, but by removing the partition wall from the support, the outer shell planned region can be communicated, and the support allows the first preceding outer shell portion and the second preceding outer shell portion to communicate with each other. Can be supported.

  In addition, the trailing outer shell of the following shield tunnel does not necessarily need to be composed of the main girder, the joint plate, the ribs, and the skin plate. After the trailing shield tunnel is constructed, an opening communicating with the preceding shield tunnel is formed. Any configuration is possible as long as it is possible.

  Further, some of the steps may be performed in parallel. For example, the following shield tunnel construction process may be started before the preceding shield tunnel construction process ends. That is, the construction of the following shield tunnel may be started before the construction of all the preceding shield tunnels is completed. Also, the second trailing shield tunnel construction step may be started before the first trailing shield tunnel construction step ends. That is, the construction of the second trailing shield tunnel may be started before the construction of all the first trailing shield tunnels is completed. In addition, the shell building step may be started before the shield tunnel building step is completed. That is, the construction of the shell may be started before the construction of all shield tunnels is completed. Further, the excavation step may be started before the outer frame building step is completed.

  In addition, the outer shell may be formed of concrete cast in the entire area in the trailing outer shell of the trailing shield tunnel. It may be formed of concrete cast in a region formed by an inner peripheral surface and an outer peripheral surface having a substantially circular shape (substantially circular arc shape) that follows from the scheduled body region. In this case, a formwork is installed in the area where concrete is cast in the trailing outer shell of the trailing shield tunnel, a cuttable filler or the like is cast outside the formwork, and inside the formwork. You may cast concrete to be the shell.

  Further, the sectional shape of the shield tunnel, the number of the shield tunnel, the number of the preceding shield tunnel and the number of the following shield tunnel are not particularly limited.

DESCRIPTION OF SYMBOLS 1 ... Underground structure, 1a ... One end, 1b ... The other end, 2 ... Main line shield tunnel, 3 ... Branch line shield tunnel, 4 ... Underground cavity, 11 ... Shield tunnel, 11A ... Outer shell, 12 ... Outer frame, 13: leading shield tunnel, 13A: leading shell, 13AA: first leading shell, 13AB: second leading shell, 13B: outer shell scheduled area, 13C: inner circumference side area, 13D: outer circumference side area, 13E: scheduled cutting area, 13F: scheduled cutting area, 13G: side part, 13H: side part, 13J: central part, 14: trailing shield tunnel, 14A: trailing outer shell, 15: one side joint wall, 16 ... 21: starting base, 22: starting well, 23: circumferential shield tunnel, 30: segment, 31: main girder, 32: joint plate, 33: skin plate, 34: opening, 40: support unit, 41A 1st partition, 41B ... 2nd partition, 42A ... 1st support, 42B ... 2nd support, 43A ... inner peripheral side support girder, 43B ... outer peripheral side support girder, 44A ... inner peripheral side shielding plate, 44B ... outer peripheral side shielding Plate, 45: Internal space, 50A: Concrete casting area, 50B: Concrete casting area, 51A: Cutable filler area, 51B: Cutable filler area, 61: Reinforcing bar, 62: Concrete, 141: After first Row shield tunnel, 142: second trailing shield tunnel, A1: first area, A2: second area.

Claims (8)

An outer shell of an underground structure,
A leading shield tunnel having a leading shell,
A trailing shield tunnel having a trailing shell, which is superimposed on the leading shield tunnel in a state where the leading shell of the leading shield tunnel is cut,
A first concrete that is cast into the leading shield tunnel and the trailing shield tunnel, and is integrated through an opening formed in a part of the trailing outer shell of the trailing shield tunnel;
A unit having a shape steel installed in the preceding shield tunnel,
And a second concrete disposed between the preceding shell and the first concrete,
Outer skeleton. The unit includes a shielding plate that partitions the first concrete and the second concrete, and a support girder made of a steel mold disposed on the first concrete side of the shielding plate.
An outer shell according to claim 1. An outer shell building method for building an outer shell of an underground structure,
A leading shield tunnel construction step of building a leading shield tunnel having a leading outer shell,
While cutting a part of the leading shield tunnel, a trailing shield tunnel construction step of constructing a trailing shield tunnel having a trailing outer shell,
An outer shell building step of building the outer shell by casting first concrete in the preceding shield tunnel and the subsequent shield tunnel,
In the preceding shield tunnel construction step, a unit having a shape steel is installed in the outer shell scheduled area where concrete is cast in the outer shell construction step in the outer shell, and the preceding outer shell and the outer shell schedule are provided. Place second concrete in the area between the area and
In the succeeding shield tunnel construction step, the leading shield tunnel is cut to cut the leading outer shell to construct the trailing shield tunnel,
In the outer shell construction step, a part of the trailing outer shell of the trailing shield tunnel is removed, and concrete is poured into the outer shell scheduled area and the trailing shield tunnel of the preceding shield tunnel. Unite,
Outer frame construction method. The unit includes a shielding plate that partitions the first concrete and the second concrete, and a support girder made of a steel mold disposed on the first concrete side of the shielding plate.
The method for constructing a shell according to claim 3. An outer shell of an underground structure,
A leading shield tunnel having a leading shell,
A trailing shield tunnel overlapping the leading shield tunnel and having a trailing outer shell;
Concrete that is cast in the leading shield tunnel and the trailing shield tunnel, and is integrated through an opening formed in a part of the trailing outer shell of the trailing shield tunnel,
A unit having a shape steel installed in the preceding shield tunnel,
Reinforcing bars extending between the leading shield tunnel and the trailing shield tunnel through the opening,
Outer skeleton. The unit has an inner peripheral support girder, and an outer peripheral support girder disposed closer to the outer periphery of the outer frame than the inner peripheral support girder,
An outer shell according to claim 5. An outer shell building method for building an outer shell of an underground structure,
A leading shield tunnel construction step of building a leading shield tunnel having a leading outer shell,
While cutting a part of the leading shield tunnel, a trailing shield tunnel construction step of constructing a trailing shield tunnel having a trailing outer shell,
An outer frame construction step of constructing the outer frame by casting concrete in the preceding shield tunnel and the subsequent shield tunnel,
In the preceding shield tunnel building step, in the outer shell, in the outer shell scheduled area where concrete is cast in the outer shell building step, a unit having a shape steel is installed,
A reinforcing bar is bridged between the preceding shield tunnel and the following shield tunnel through an opening formed by removing a part of the following outer shell of the following shield tunnel,
In the outer shell construction step, concrete is poured into the outer shell scheduled area and the subsequent shield tunnel of the preceding shield tunnel and integrated therewith,
Outer frame construction method. The unit has an inner peripheral support girder, and an outer peripheral support girder disposed closer to the outer periphery of the outer frame than the inner peripheral support girder,
The method for constructing a shell according to claim 7.