JP2017043982A - Underground structure, and construction method of underground structure - Google Patents

Underground structure, and construction method of underground structure Download PDF

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Publication number
JP2017043982A
JP2017043982A JP2015167713A JP2015167713A JP2017043982A JP 2017043982 A JP2017043982 A JP 2017043982A JP 2015167713 A JP2015167713 A JP 2015167713A JP 2015167713 A JP2015167713 A JP 2015167713A JP 2017043982 A JP2017043982 A JP 2017043982A
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Japan
Prior art keywords
tunnel
underground structure
constructing
structure according
space
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Inventor
幸夫 多田
Yukio Tada
幸夫 多田
研吾 佐藤
Kengo Sato
研吾 佐藤
須田 久美子
Kumiko Suda
久美子 須田
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鹿島建設株式会社
Kajima Corp
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Abstract

An underground structure capable of including a part of a tunnel in a state where a vehicle or the like can pass through the existing tunnel is constructed. An underground structure (1) includes an existing main tunnel (2), a plurality of tunnels (21, 22) built in the ground so as to extend along the main tunnel (2), and between the tunnels (21, 22) in the ground. And a plurality of annular structures 30 that are constructed by bridging the curved steel pipes 31 and 32 and surround the main tunnel 2. The underground structure 1 has a space 52 between the plurality of structures 30 and the main line tunnel 2. The plurality of structures 30 are arranged at intervals in the axial direction of the main tunnel 2. [Selection] Figure 8

Description

  The present invention relates to an underground structure and a construction method thereof.

  A NEW TULIP method (registered trademark) is known as an example of a non-cutting method for constructing an underground space. This method is an example of a curved pipe roof method.For example, a curved steel pipe is propelled and installed from an existing tunnel, and the underground space is constructed without cutting by using a curved steel pipe alone or with ground improvement such as the freezing method or chemical injection. (Refer nonpatent literature 1).

  In this regard, in Patent Document 1, in the method for constructing an underground structure, when excavating each facing side of the tunnels provided to form the widened portion, an excavator is installed from one tunnel side to the other tunnel side. The curved steel pipes described above are propelled and installed by pushing them forward and installing them so that a plurality of steel pipes are connected in a circular arc shape. Patent Document 2 discloses an example of a propulsion device that propels the curved steel pipe described above. Patent Document 3 discloses an example of the excavator described above.

Japanese Patent Laid-Open No. 2004-124489 JP 2009-125782 A JP 2008-144507 A

"NEW TULIP Method", [online], NEW TULIP Method Liaison Committee, [Search August 17, 2015], Internet <URL: http://new-tulip.com/>

By the way, for example, when the ramp portion is constructed in the middle of an existing underground road tunnel, it is preferable to construct the ramp portion while a vehicle can pass through the underground road tunnel.
However, when constructing the ramp portion, if the curved steel pipe installation method disclosed in Patent Documents 1 to 3 and Non-Patent Document 1 described above is applied to an existing underground road tunnel, the above-described propulsion is performed in the underground road tunnel. Since it was necessary to install a device, it was necessary to restrict the passage of vehicles in the underground road tunnel.

  In view of such a situation, an object of the present invention is to construct an underground structure capable of including a part of the tunnel while a vehicle or the like can pass through the existing tunnel.

  Therefore, in the construction method of the underground structure according to the present invention, so as to extend alongside the existing tunnel, to construct a plurality of guide shafts in the ground, to bridge the steel pipe between the guide shafts in the ground, including.

  In addition, the underground structure according to the present invention is constructed by bridging a steel pipe between an existing tunnel, a plurality of guide shafts built in the ground so as to extend along the tunnel, and the guide shaft in the ground. And an annular structure surrounding the periphery of the tunnel. This underground structure has a space between the structure and the tunnel.

  According to the present invention, a plurality of guide shafts are constructed in the ground so as to extend alongside existing tunnels, and steel pipes are bridged between the guide shafts in the ground. Thereby, since the above-mentioned propulsion device can be installed in the guide shaft, an underground structure capable of including a part of the tunnel can be constructed without restricting the passage of vehicles or the like in the existing tunnel. .

The figure which shows schematic structure of the underground structure in 1st Embodiment of this invention. The figure which shows the construction method of the underground structure in embodiment same as the above The figure which shows the construction method of the underground structure in embodiment same as the above The figure which shows the construction method of the underground structure in embodiment same as the above The figure which shows the construction method of the underground structure in embodiment same as the above The figure which shows the construction method of the underground structure in embodiment same as the above The figure which shows the construction method of the underground structure in embodiment same as the above The figure which shows the construction method of the underground structure in embodiment same as the above The figure which shows the construction method of the underground structure in embodiment same as the above The figure which shows the curved steel pipe, freezing pipe, and frozen soil layer in embodiment same as the above The figure which shows the creation process of the groundwater flow suppression improvement body in 2nd Embodiment of this invention. The figure which shows the modification of the shaft

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a schematic configuration of an underground structure in the first embodiment of the present invention. Specifically, FIG. 1A is a top view of the underground structure, and FIG. 1B is a cross-sectional view taken along line AA of FIG. In this embodiment, as an example of a method for constructing an underground structure, an example in which a ramp portion is provided in the middle of an existing underground road tunnel will be described below. However, the method for constructing an underground structure according to the present invention is described below. Not limited to. Further, the underground structure is not limited to the one constituting the lamp part. In addition, for convenience of explanation, front and rear, left and right are defined as shown in FIG.

In the present embodiment, the underground structure 1 constitutes a junction where the ramp tunnel 3 joins the main tunnel 2 which is an existing tunnel that has been excavated and formed in advance in the ground.
The main tunnel 2 is a shield tunnel and includes a cylindrical cover 4 (see FIG. 2B described later). The lining body 4 is constructed by connecting arc-shaped segments (not shown) in the tunnel circumferential direction and the tunnel axis direction. Note that a floor slab 5 and a support member 6 that supports the floor slab 5 are provided in the lining body 4 of the main tunnel 2. A vehicle or the like can run on the floor slab 5.

The lamp tunnel 3 provided side by side with the main tunnel 2 is a shield tunnel, and includes a cylindrical covering body 7 (see FIG. 2B described later). The lining body 7 is constructed by connecting arc-shaped segments (not shown) in the tunnel circumferential direction and the tunnel axis direction. Here, the covering body 7 of the lamp tunnel 3 has a smaller diameter cross section than the covering body 4 of the main tunnel 2.
In the present embodiment, the cross-sectional shapes of the main tunnel 2 and the lamp tunnel 3 are circular. However, the cross-sectional shape is not limited to this, and may be, for example, an elliptical shape or a rectangular shape.

  As shown in FIG. 1, the underground structure 1 includes anchored concrete 11 and 12, lining concrete 13, and a plurality of (two in FIG. 1) guide shafts 21 that constitute front and rear ends of the underground structure 1. , 22 and a plurality of annular (ring-shaped) structures 30.

  The lining concrete 13 has a cylindrical shape extending in the front-rear direction, and has a diameter that decreases from the rear side toward the front side. The front end portion of the lining concrete 13 is connected to the rear portion of the front wall concrete 11. The rear end portion of the lining concrete 13 is connected to the front portion of the rear side wall concrete 12.

  The front wall concrete 11 has a substantially columnar shape, and the main tunnel 2 passes through the center in the front-rear direction. The rear side wall concrete 12 has a substantially cylindrical shape, and the main tunnel 2 penetrates in the front-rear direction on the right side, and the lamp tunnel 3 penetrates in the front-rear direction on the left side. In addition, the shape of the wall concrete 11 and 12 is not limited to a substantially cylindrical shape, and may be a substantially rectangular parallelepiped shape, for example. Moreover, the construction of the wall concrete 11 and 12 can be performed in parallel with the construction of the structure 30 and the construction of the lining concrete 13 which will be described later. Further, prior to the construction of the eaves wall concrete 11, 12, a freezing improvement body (not shown) for eaves water stop may be created so as to include the planned construction location of the eaves wall concrete 11, 12.

  The plurality of structures 30 are arranged at intervals in the front-rear direction. In the present embodiment, the structural body 30 has an annular shape, and the lining concrete 13 is constructed adjacent to the inside thereof. In the present embodiment, the structure 30 has an annular shape, but the shape of the structure 30 is not limited to this, and may be, for example, an elliptical shape. The structure 30 has a CFT (concrete filled steel pipe) structure.

  The guide shaft 21 is a shield tunnel (tunnel), and extends in the front-rear direction along the lining concrete 13 on the right side of the lining concrete 13. The guide shaft 22 is a shield tunnel (tunnel), and extends in the front-rear direction along the lining concrete 13 on the left side of the lining concrete 13. Each structure 30 penetrates the guide shafts 21 and 22 up and down. The internal spaces 21a and 22a of the guide shafts 21 and 22 are filled with a filler such as mortar, respectively.

In the lining concrete 13, a bottom concrete 41, a plurality of (two in FIG. 1B) supporting concrete 42, and a floor slab 43 are provided.
In a space 44 surrounded by the bottom concrete 41 and the bottom of the lining concrete 13, for example, excavated earth and sand generated during construction of the underground structure 1 is backfilled.

The supporting concrete 42 is supported by the bottom concrete 41 and supports the floor slab 43 from below.
A space 45 defined by the floor slab 43, the supporting concrete 42, and the bottom concrete 41 can be used as an escape passage, for example.

A space 46 is defined in the lining concrete 13 by the inner peripheral surface thereof and the upper surface of the floor slab 43.
Here, the upper surface of the floor slab 43, the upper surface of the floor slab 5 of the main tunnel 2 and the upper surface of the floor slab (not shown) of the ramp tunnel 3 are continuous so that a vehicle or the like can pass.

  Next, the construction method of the underground structure 1 will be described with reference to FIGS. 2 to 9 in addition to FIG. 2-9 is a figure which shows the construction method of the underground structure 1. FIG. Here, FIG. 2 (a), FIG. 3 (a), FIG. 4 (a), FIG. 5 (a), and FIG. 6 (a) looked at the transition of the construction of the underground structure 1 from above. FIG. FIG.2 (b) is BB sectional drawing of Fig.2 (a). FIG.3 (b) is CC sectional drawing of Fig.3 (a). FIG. 4B is a DD cross-sectional view of FIG. FIG.5 (b) is EE sectional drawing of Fig.5 (a). 6B and 6C correspond to the FF cross section of FIG. 6A, respectively. Fig.7 (a)-FIG.9 (b) each show transition of the construction of the underground structure 1 in the FF cross section of Fig.6 (a).

  Here, in the construction method of the underground structure 1, mainly, the construction of the guide shafts 21 and 22, the construction of the plurality of structures 30, the construction of the lining concrete 13, and the lining concrete 13 The installation of the floor slab 43 will be described. Although the illustration of the construction of the eaves concrete 11 and 12 is omitted, the construction of the plurality of structures 30 and the construction of the lining concrete 13 can be performed in parallel.

First, as shown in FIGS. 2A and 2B, the ramp tunnel 3 is formed by excavation using the shield machine 9 until it is adjacent to the existing main tunnel 2.
Next, as shown in FIGS. 3 (a) and 3 (b), freezing improvement bodies 25 and 26 made of frozen soil are created by freezing the ground so as to include the construction planned locations of the horizontal shafts 23 and 24 described later. To do. Here, a well-known freezing method may be used for the formation of the freeze improvement bodies 25 and 26. In the present embodiment, the freezing improvement body 25 is formed so as to overlap the right side of the main tunnel 2, and the freezing improvement body 26 is formed so as to overlap the left side of the ramp tunnel 3.

Next, as shown in FIGS. 4A and 4B, the horizontal shafts 23 and 24 are constructed in the freezing improved bodies 25 and 26.
The horizontal shaft 23 is formed on the right side of the main tunnel 2, and the internal space communicates with the internal space of the main tunnel 2. In addition, in this embodiment, although the horizontal shaft 23 has comprised the rectangular box shape, the shape of the horizontal shaft 23 is not restricted to this. Here, the horizontal shaft 23 can function as a starting base for a shield machine (not shown) used to construct the guide shaft 21.

  The horizontal shaft 24 is formed on the left side of the lamp tunnel 3, and its internal space communicates with the internal space of the lamp tunnel 3. In this embodiment, the horizontal shaft 24 has a rectangular box shape, but the shape of the horizontal shaft 24 is not limited to this. Here, the horizontal shaft 24 can function as a starting base for a shield machine (not shown) used to construct the guide shaft 22.

  In this embodiment, the horizontal shaft 23 can be located in the front part of the underground structure 1 (for example, the connection part of the wall concrete 11 and the lining concrete 13). Moreover, the horizontal shaft 24 can be located in the rear part of the underground structure 1 (for example, the connection part of the lining concrete 13 and the wall concrete 12).

  Next, as shown in FIGS. 5 (a) and 5 (b), while starting a shield machine from within the horizontal shaft 23, while excavating natural ground along the main tunnel 2 from the front side to the rear side, By connecting a plurality of segments one after another at the tail portion of the shield machine, a guide shaft 21 including a cylindrical lining body is constructed. The main tunnel 2 and the ramp tunnel 3 are located between the leading end 21 b of the guide shaft 21 and the horizontal shaft 24.

In addition, the shield machine is started from the inside of the horizontal pit 24, and excavated from the rear side to the front side and gradually into the main tunnel 2 while gradually moving at the tail part of the shield machine. By connecting a plurality of segments, the guide shaft 22 including a cylindrical lining body is constructed. In addition, the main line tunnel 2 is located between the front end portion 22 b of the guide shaft 22 and the horizontal shaft 23.
In this way, around the existing main tunnel 2 (that is, outside the main tunnel 2), and extending along the main tunnel 2 (that is, parallel to the main tunnel 2), the guide shafts 21, 22 is built in the ground.

The guide shaft 21 is branched from the main tunnel 2 via the horizontal shaft 23. Further, the guide shaft 22 is branched from the ramp tunnel 3 via the horizontal shaft 24.
Here, the horizontal shafts 23 and 24 can function as “branch portions” of the present invention, and are constructed prior to constructing the guide shafts 21 and 22. Prior to the construction of the horizontal shafts 23, 24, the freeze improvement bodies 25, 26 are formed so as to include the planned construction locations of the horizontal shafts 23, 24.

  Next, as shown in FIGS. 6 (a) to 6 (c), a plurality of semicircular arch-shaped curves convex upward between the horizontal shaft 23 and the horizontal shaft 21 and the horizontal shaft 22 and the horizontal shaft 24. A steel pipe 31 and a plurality of curved steel pipes 32 having a semicircular arch shape projecting downward are bridged. Here, the plurality of curved steel pipes 31 are arranged at intervals in the axial direction of the main tunnel 2. A plurality of curved steel pipes 32 are also arranged at intervals in the axial direction of the main tunnel 2. Moreover, it is preferable that the number of the curved steel pipes 31 arranged in the axial direction of the main tunnel 2 and the number of the curved steel pipes 32 are the same. Moreover, it is preferable that the curved steel pipe 32 is located directly under each curved steel pipe 31, respectively.

  The curved steel pipe 32 is, for example, by pushing the excavator 33 (see FIG. 6B) from the guide pit 21 side to the guide pit 22 side and connecting a plurality of steel pipes (not shown) in a circular arc shape, It can be installed in the ground. In addition, the curved steel pipe 31 is formed by, for example, pushing a drilling machine (not shown) from the guide pit 22 side to the guide pit 21 side and connecting a plurality of steel pipes (not shown) in an arc shape while connecting them. Can be installed. Note that both of the guide shafts 21 and 22 can be used for starting an excavator for installing the curved steel pipes 31 and 32. Further, a propulsion device (not shown) for propelling the curved steel pipes 31 and 32 may be provided in the guide shaft used for starting the excavator. In this propulsion device, for example, an inclined gantry (not shown) having a curved flange (not shown) having the same curvature as the curved steel pipes 31 and 32, and one end of the inclined gantry is rotated by a leg portion of the inclined gantry. The curved steel pipes 31 and 32 can be propelled into the ground by controlling the stroke of the propulsion jack (not shown). Such a propulsion device is disclosed in Patent Document 2, for example. An example of the excavator 33 is disclosed in Patent Document 3.

  In this way, the curved steel pipes 31 and 32 are bridged between the guide shafts 21 and 22 in the ground. In addition, bridging the curved steel pipes 31 between the guide shafts 21 and 22 means that the curved steel pipes 31 are arranged in the guide shafts 21 and 22 so that the plurality of curved steel pipes 31 are arranged at intervals in the axial direction of the main tunnel 2. Includes bridging between them. In addition, bridging the curved steel pipes 32 between the guide shafts 21 and 22 means that the curved steel pipes 32 are arranged in the guide tunnels 21 and 22 so that the plurality of curved steel pipes 32 are arranged at intervals in the axial direction of the main tunnel 2. Includes bridging between them.

  Next, as shown in FIG. 7A, the frozen ground layer 35 is formed by freezing the surrounding ground of the plurality of curved steel pipes 31 aligned in the axial direction of the main tunnel 2 and aligned in the axial direction of the main tunnel 2. The frozen ground layer 36 is formed by freezing the surrounding ground of the plurality of curved steel pipes 32.

Here, formation of the frozen soil layer 35 will be described with reference to FIG.
FIG. 10 corresponds to an upper cross-sectional view of a plurality of curved steel pipes 31 arranged in the axial direction of the main tunnel 2, and shows the curved steel pipe 31, the frozen pipe 37, and the frozen soil layer 35.

  As shown in FIG. 10, the freezing pipes 37 are provided on both the front and rear sides on the natural mountain side in the curved steel pipe 31 (that is, the side opposite to the main line tunnel 2). The freezing pipe 37 extends along the extending direction of the curved steel pipe 31. The inside of the freezing pipe 37 can be made to flow a refrigerant by a pump or the like (not shown) installed in advance in any of the guide shafts 21 and 22 and the horizontal shafts 23 and 24. Here, as an example of the refrigerant, an antifreeze such as salt water can be cited. Therefore, when the refrigerant is caused to flow through the freezing pipe 37, the surrounding ground is frozen through the curved steel pipe 31 in the vicinity of the freezing pipe 37 and the frozen soil layer 35 is formed as shown in FIG. The frozen soil layer 35 is formed so as to close the gap between the curved steel pipes 31 and to cover all the installed curved steel pipes 31 from the ground side (that is, the side opposite to the main tunnel 2).

  Although illustration is omitted, the curved steel pipe 32 is also provided with a freezing pipe 37, similarly to the curved steel pipe 31. Therefore, when a refrigerant is passed through the freezing pipe 37, the surrounding ground is frozen through the curved steel pipe 32 in the vicinity of the freezing pipe 37, and a frozen soil layer 36 is formed. The frozen soil layer 36 is formed so as to close the gap between the curved steel pipes 32 and to cover all the installed curved steel pipes 32 from the natural ground side (that is, the side opposite to the main tunnel 2).

  Accordingly, in the region surrounded by the frozen soil layers 35 and 36 (that is, in the structure 30), the inflow of groundwater from the surrounding ground is suppressed by the frozen soil layers 35 and 36 (that is, by the frozen soil layers 35 and 36). Water is stopped).

  Next, concrete is filled in all the curved steel pipes 31 and 32. Thereby, it can be set as a CFT structure. Here, since the piping is made in advance so that the refrigerant can circulate in the freezing pipe 37 even after the concrete is filled in the curved steel pipes 31 and 32, the frozen soil layers 35 and 36 can be continuously formed.

Next, as shown in FIG. 7B, the left and right ends (lower end) of each curved steel pipe 31 are connected to the left and right ends (upper end) of the curved steel pipe 32 via connecting members 38, respectively. Here, the connection member 38 is disposed in the guide shafts 21 and 22. An annular structure 30 is constructed by connecting one curved steel pipe 31 and one curved steel pipe 32 via two connecting members 38. In this way, a plurality of structures 30 are formed. Therefore, the plurality of structures 30 are arranged at intervals in the axial direction of the main tunnel 2. The connecting member 38 is carried into the guide shafts 21 and 22 from the horizontal shafts 23 and 24.
Moreover, in this embodiment, the cyclic | annular structure 30 is constructed by spanning the curved steel pipes 31 and 32 between the guide shafts 21 and 22, and the circumference | surroundings of the main tunnel 2 are surrounded by the structure 30. In the place where the lamp tunnel 3 is adjacent to the main tunnel 2, the structure 30 surrounds the periphery of the main tunnel 2 and the lamp tunnel 3.

  Next, as shown in FIGS. 8A and 8B, the space 52 is formed by excavating the earth and sand 51 inside the structure 30 and outside the main tunnel 2 and the ramp tunnel 3. . That is, the space 52 is formed between the structure 30 and the main tunnel 2 and the ramp tunnel 3 by excavating the earth and sand 51 between the structure 30 and the main tunnel 2 and the ramp tunnel 3. . A heavy machine such as a backhoe used for excavation of the earth and sand 51 is, for example, an opening formed by previously cutting a part of the lining body 4 of the main tunnel 2 near the horizontal shaft 23 or a part of the guide shafts 21 and 22. Through a section (not shown), it can enter the structure 30 and go to the excavation site. The excavation of the earth and sand 51 is advanced from top to bottom and from the front side to the rear side, for example, as in a bench cut method. In addition, when the above-mentioned opening is formed, or when the above-mentioned heavy machinery passes through the opening, in the portion close to the above-mentioned opening of the main tunnel 2, temporary closure of vehicles, etc. Although the number of lanes can be reduced, basically, the state in which the vehicle can pass is continued.

Further, as shown in FIGS. 8A and 8B, in accordance with the expansion of the space 52 accompanying the progress of excavation of the earth and sand 51, a region 53 (FIG. 8 (a) and a thick solid line part shown in (b)), while installing a water stop iron plate, spray mortar.
When the progress of the excavation of the earth and sand 51 proceeds to the center in the vertical direction of the structure 30, the side wall concrete 13a is placed as shown in FIG. Here, the side wall concrete 13a constitutes a part of the lining concrete 13 described above. In addition, about the segment which comprises the part into which the side wall concrete 13a is casted among the guide shafts 21 and 22, it is removed prior to the casting of the side wall concrete 13a. That is, a part of the guide shafts 21 and 22 is removed prior to the placement of the side wall concrete 13a.

  Here, in the steps shown in FIGS. 8A and 8B, the space 52 is not in communication with the space in the main tunnel 2 when viewed in the cross section of the main tunnel 2 (the paper surface in FIG. 8).

  Next, as shown in FIG. 9A, arch concrete 13b is placed so as to be continuous with the side wall concrete 13a. Here, the arch concrete 13b constitutes a part of the lining concrete 13 described above.

  Further, as shown in FIG. 9A, the upper half of the portion located inside the structure 30 in the lining body 4 of the main tunnel 2 is removed. Here, the lining body 4 forms a peripheral wall of the main tunnel 2, and therefore, at least a part of the peripheral wall of the main tunnel 2 is removed. Thereby, the space 52 and the space in the main line tunnel 2 communicate. Although not shown, the upper half of the covering body 7 of the lamp tunnel 3 that is located inside the structure 30 is also removed. Here, the lining body 7 forms a peripheral wall of the lamp tunnel 3, and therefore, at least a part of the peripheral wall of the lamp tunnel 3 is removed. Thereby, the space 52 and the space in the lamp tunnel 3 communicate with each other. At this time, the shield machine 9 can be removed.

  Here, in the step shown in FIG. 9A, the space 52 communicates with the space in the main tunnel 2 when viewed from the cross section of the main tunnel 2 (the paper surface in FIG. 8).

  Next, the excavation of the earth and sand 51 is advanced, and as shown in FIG. 9B, the inverted concrete 13c is placed so as to be continuous with the side wall concrete 13a. Here, the invert concrete 13c constitutes a part of the lining concrete 13 described above. Therefore, the lining concrete 13 having an annular cross section is formed by the side wall concrete 13a, the arch concrete 13b, and the invert concrete 13c.

  In the lining concrete 13, a bottom concrete 41, a plurality (two in FIG. 9B) supporting concrete 42 and a floor slab 43 are provided. In the space 44 surrounded by the bottom concrete 41 and the bottom of the lining concrete 13, excavated earth and sand are backfilled as described above.

  In addition, when providing the floor slab 43, it is necessary to remove the floor slab 5 in the main line tunnel 2 located in the installation planned location. For this reason, for example, prior to the removal of the floor slab 5, a temporary floor slab (not shown) is installed on the left side of the floor slab 5 in the structure 30, and a vehicle or the like passes over the installation floor slab. By making it possible, it is possible to allow a vehicle or the like to pass through the structure 30 during the period from the removal of the floor slab 5 to the installation of the floor slab 43.

Moreover, the frozen soil layers 35 and 36 are thawed by stopping the circulation of the refrigerant in the freezing pipe 37 (see FIG. 1B).
In addition, the internal spaces 21a and 22a of the guide shafts 21 and 22 are filled with a filler such as mortar, respectively.
As described above, the underground structure 1 shown in FIGS. 1A and 1B is constructed.

  According to this embodiment, the construction method of the underground structure 1 includes constructing a plurality of guide shafts 21 and 22 in the ground so as to extend alongside the existing main line tunnel 2 (tunnel), Bridging curved steel pipes 31 and 32 (steel pipes) between the guide shafts 21 and 22. Thereby, since the propulsion device for propelling the curved steel pipes 31 and 32 can be installed in the guide shafts 21 and 22, without restricting the passage of vehicles and the like in the existing main tunnel 2, The underground structure 1 (structure 30) that can partially include the structure can be constructed.

  Further, according to the present embodiment, the guide shaft 21 is branched from the main tunnel 2. Thereby, the main tunnel 2 can be easily accessed from the inside of the guide tunnel 21. In the present embodiment, the guide shaft 22 is branched from the ramp tunnel 3, but it goes without saying that it may be branched from the main tunnel 2 instead.

  Moreover, according to this embodiment, the construction method of the underground structure 1 further includes constructing a branching portion (horizontal shaft 23) from the main tunnel 2 to the guiding shaft 21 before constructing the guiding shaft 21. . Thereby, the horizontal pit 23 can be used as a start base of the shield machine for construction of the guide pit 21.

  Moreover, according to this embodiment, the construction method of the underground structure 1 further includes constructing a branching portion (lateral shaft 24) from the ramp tunnel 3 to the shaft 22 before the shaft 22 is constructed. . Thereby, the horizontal shaft 24 can be used as a starting base of the shield machine for constructing the guide shaft 22. In the present embodiment, the horizontal shaft 24 is a branching portion from the ramp tunnel 3 to the shaft 22, but the horizontal shaft 24 is not a branching portion from the main tunnel 2 to the shaft 22. May be. In this case, for example, the horizontal shaft 24 can be constructed at a position facing the horizontal shaft 23 across the main tunnel 2.

  Moreover, in this embodiment, the construction method of the underground structure 1 is freeze-improved so as to include the planned construction location of the branch portion (the horizontal shafts 23, 24) prior to the construction of the branch portion (the horizontal shafts 23, 24). It further includes creating the bodies 25,26. Thereby, the water stoppage of the construction planned place of the horizontal shafts 23 and 24 is securable.

  Further, according to the present embodiment, bridging the curved steel pipes 31 (steel pipes) between the guide shafts 21 and 22 is such that a plurality of curved steel pipes 31 are arranged at intervals in the axial direction of the main tunnel 2. It includes bridging the curved steel pipe 31 between the guide shafts 21 and 22. Thereby, the curved pipe roof which can comprise the upper half of the underground structure 1 can be constructed | assembled.

  Further, according to the present embodiment, bridging the curved steel pipes 32 (steel pipes) between the guide shafts 21 and 22 is such that a plurality of curved steel pipes 32 are arranged at intervals in the axial direction of the main tunnel 2. This includes bridging the curved steel pipe 32 between the guide shafts 21 and 22. Thereby, the curved pipe roof which can comprise the lower half of the underground structure 1 can be constructed | assembled.

  Moreover, according to this embodiment, the construction method of the underground structure 1 further includes forming the frozen soil layer 35 by freezing the surrounding ground of the plurality of curved steel pipes 31 (steel pipes) arranged in the axial direction of the main tunnel 2. Including. Thereby, the water stoppage can be ensured by the curved pipe roof composed of the plurality of curved steel pipes 31.

  Moreover, according to this embodiment, the construction method of the underground structure 1 further includes forming the frozen soil layer 36 by freezing the surrounding ground of the plurality of curved steel pipes 32 (steel pipes) arranged in the axial direction of the main tunnel 2. Including. Thereby, the water stoppage can be ensured by the curved pipe roof formed of the plurality of curved steel pipes 32.

  Moreover, according to this embodiment, the construction method of the underground structure 1 further includes filling concrete into the curved steel pipes 31 and 32 (steel pipes) spanned between the guide shafts 21 and 22. Thereby, the structure 30 can be made into a CFT structure.

  Moreover, according to this embodiment, the construction method of the underground structure 1 constructs the annular structure 30 by bridging the curved steel pipes 31 and 32 (steel pipes) between the guide shafts 21 and 22. It further includes surrounding the tunnel 2. Thereby, the pressure from the surrounding natural ground can be satisfactorily received by the structure 30.

  Further, according to the present embodiment, the plurality of structures 30 are arranged at intervals in the axial direction of the main tunnel 2. Thereby, the space 52 can be formed in the annular curved pipe roof.

  Moreover, according to this embodiment, the construction method of the underground structure 1 excavates the earth and sand 51 between the structure 30, the main line tunnel 2, and the lamp tunnel 3, and the structure 30, the main line tunnel 2, the lamp tunnel 3, Further, a space 52 is formed between them (see FIGS. 8A and 8B). Thereby, an expansion space can be formed in the structure 30.

  Moreover, according to this embodiment, the construction method of the underground structure 1 further includes communicating the space 52 and the space in the main tunnel 2 by removing at least a part of the peripheral wall of the main tunnel 2 ( FIG. 9 (a)). Thereby, the space in the main line tunnel 2 can be substantially expanded in the up-down direction and the left-right direction.

  According to the present embodiment, the underground structure 1 includes an existing main tunnel 2 (tunnel), a plurality of guide shafts 21 and 22 constructed in the ground so as to extend along the main tunnel 2, And an annular structure 30 that is constructed by bridging curved steel pipes 31 and 32 (steel pipes) between the guide tunnels 21 and 22 and surrounding the main tunnel 2. Moreover, the underground structure 1 has the space 52 between the structure 30 and the main line tunnel 2 (refer Fig.8 (a) and (b)). As a result, a large underground space adjacent to the main tunnel 2 can be formed.

  Further, according to the present embodiment, the space 52 is in communication with the space in the main tunnel 2 as seen in the cross section of the main tunnel 2 (see FIG. 9A). Thereby, the space in the main tunnel 2 is substantially expanded in the vertical direction and the horizontal direction.

  Further, according to the present embodiment, the space 52 is not in communication with the space in the main tunnel 2 as seen in the cross section of the main tunnel 2 (see FIGS. 8A and 8B). Thereby, in the predetermined cross section of the main tunnel 2, the space 52 and the space in the main tunnel 2 are partitioned by the lining body 4 of the main tunnel 2, so that dust generated at the excavation site of the earth and sand 51 is generated. Direct inflow into the main tunnel 2 can be suppressed.

FIG. 11: is a figure which shows the creation process of the groundwater flow suppression improvement body in 2nd Embodiment of this invention.
A different point from 1st Embodiment shown in FIGS. 1-10 is demonstrated.
In the present embodiment, in the construction method of the underground structure 1 described above, prior to forming the frozen ground layers 35 and 36 (see FIG. 7A), the flow of groundwater around the curved steel pipes 31 and 32 is changed. A groundwater flow suppression improvement body 55 to be suppressed is created.

  The groundwater flow suppression improvement body 55 is formed in order to suppress the flow of groundwater in the region 56 when, for example, there is a region 56 in which the frozen soil temperature is difficult to decrease. The groundwater flow suppression improvement body 55 has a function of reducing the hydraulic conductivity of natural ground. The groundwater flow suppression improved body 55 can be constructed from the guide shafts 21 and 22 using a well-known chemical solution injection method, a high-pressure jet stirring method, or the like. It should be noted that the solidified material can be injected into the planned construction site of the groundwater flow suppression improved body 55 from the guide shafts 21 and 22 through appropriate injection means (not shown).

  The groundwater flow suppression improvement body 55 is outside the curved steel pipes 31 and 32 (the ground side (the side opposite to the main line tunnel 2)) and outside the planned freezing region of the frozen soil layers 35 and 36 (the ground side (the main line). The side opposite to the tunnel 2)). Moreover, the groundwater flow suppression improvement body 55 can be formed so that the area | region (groundwater flow suppression object area | region) where suppression of the flow of groundwater is calculated | required among the surrounding natural grounds of the curved steel pipes 31 and 32 may be enclosed.

  In particular, according to the present embodiment, the construction method of the underground structure 1 is a groundwater flow suppression improvement body that suppresses the flow of groundwater in the surrounding ground around the curved steel pipes 31 and 32 before the formation of the frozen soil layers 35 and 36. Further comprising creating 55. Thereby, since the hydraulic conductivity of the surrounding natural ground of the curved steel pipes 31 and 32 can be lowered | hung and the flow of groundwater can be suppressed, formation of the frozen soil layers 35 and 36 can be assisted.

  In the first and second embodiments described above, the example in which the two guiding shafts 21 and 22 are constructed at the time of constructing the underground structure 1 has been described. However, the number of constructed guiding shafts is two or more. For example, as shown in FIG. 12A, three guide shafts 20, 21, and 22 may be constructed.

In the first and second embodiments described above, the cross-sectional shape of the guide shafts 21 and 22 is circular. However, the cross-sectional shape is not limited to this, for example, an elliptical shape or a rectangular shape (FIG. 12B ))).
In the first and second embodiments described above, the cross-sectional shape of the curved steel pipes 31 and 32 is circular. However, the cross-sectional shape is not limited to this, and may be, for example, an elliptical shape or a rectangular shape. .

  The illustrated embodiments are merely examples of the present invention, and the present invention is not limited to those directly described by the described embodiments, and various improvements and modifications made by those skilled in the art within the scope of the claims. Needless to say, it encompasses changes.

DESCRIPTION OF SYMBOLS 1 Underground structure 2 Main line tunnel 3 Lamp tunnel 4 Covering body 5 Floor slab 6 Support member 7 Covering body 9 Shield machine 11 and 12 Anchor wall concrete 13 Covering concrete 13a Side wall concrete 13b Arch concrete 13c Invert concrete 20, 21 , 22 Leading pits 21a, 22a Inner spaces 21b, 22b Ends 23, 24 Horizontal pits 25, 26 Freezing improvement body 30 Structure 31, 32 Curved steel pipe 33 Excavator 35, 36 Frozen earth layer 37 Freezing pipe 38 Connection member 41 Bottom concrete 42 Support concrete 43 Floor slabs 44, 45 Space 51 Earth and sand 52 Space 53 Area 55 Groundwater flow suppression improvement body 56 Area

Claims (16)

  1. Constructing multiple shafts in the ground to extend alongside existing tunnels,
    Bridging the steel pipe between the guide shafts in the ground;
    Construction method of underground structure including
  2.   The construction method for an underground structure according to claim 1, wherein the guide shaft is branched from the tunnel.
  3.   The method for constructing an underground structure according to claim 1, further comprising constructing a branch portion from the tunnel to the guide shaft prior to constructing the guide shaft.
  4.   The method for constructing an underground structure according to claim 3, further comprising constructing a frozen improvement body so as to include a planned construction location of the branch portion prior to constructing the branch portion.
  5.   The bridging the steel pipes between the guide shafts includes bridging the steel pipes between the guide shafts such that a plurality of steel pipes are arranged at intervals in the axial direction of the tunnel. Item 5. The construction method for an underground structure according to any one of Items 4 to 5.
  6.   The method for constructing an underground structure according to claim 5, further comprising freezing a surrounding ground of the plurality of steel pipes arranged in the axial direction of the tunnel to form a frozen soil layer.
  7.   The method for constructing an underground structure according to claim 6, further comprising creating a groundwater flow suppression improvement body that suppresses a flow of groundwater in the surrounding ground prior to forming the frozen soil layer.
  8.   The construction method of an underground structure according to any one of claims 1 to 7, further comprising filling the steel pipe spanned between the guide shafts with concrete.
  9.   The underground structure according to any one of claims 1 to 8, further comprising: constructing an annular structure by bridging the steel pipe between the guide shafts, and surrounding the tunnel by the structure. How to build a structure.
  10.   The construction method of an underground structure according to claim 9, wherein the plurality of structures are arranged at intervals in the axial direction of the tunnel.
  11.   The method for constructing an underground structure according to claim 9 or 10, further comprising excavating earth and sand between the structure and the tunnel to form a space between the structure and the tunnel.
  12.   The method for constructing an underground structure according to claim 11, further comprising communicating the space and the space in the tunnel by removing at least a part of the peripheral wall of the tunnel.
  13. The existing tunnel,
    A plurality of shafts constructed in the ground to extend alongside the tunnel,
    An annular structure that is constructed by bridging a steel pipe between the guide mine in the ground, and surrounds the tunnel,
    With
    An underground structure having a space between the structure and the tunnel.
  14.   The underground structure according to claim 13, wherein the space is in communication with a space in the tunnel as viewed in a cross section of the tunnel.
  15.   The underground structure according to claim 13, wherein the space is not in communication with a space in the tunnel as viewed in a cross section of the tunnel.
  16.   The underground structure according to any one of claims 13 to 15, wherein the plurality of structures are arranged at intervals in the axial direction of the tunnel.
JP2015167713A 2015-08-27 2015-08-27 Underground structure, and construction method of underground structure Pending JP2017043982A (en)

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JP2002227598A (en) * 2001-01-26 2002-08-14 Nippon Zenith Pipe Co Ltd Construction method for underground structure
EP1355039A1 (en) * 2002-04-20 2003-10-22 Hochtief Aktiengesellschaft Method of constructing an extended free chamber between two tunnel segments
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