JP6425010B2 - Large cross section tunnel structure and method for constructing the same - Google Patents

Description

  The present invention relates to a large cross section tunnel structure mainly applied to construction of a junction of a shield tunnel and a construction method thereof.

  In tunneling by shield method, it is necessary to widen the cross section of the tunnel at the junction of the shield tunnel, typically at the junction of the main tunnel and the ramp tunnel.

  In the case of road tunnels, the junctions and junctions of tunnels often have large cross sections exceeding 20 m in width, and even though shield machines exceeding 15 m in diameter have come to be manufactured, the junctions and junctions are limited. It is not realistic to excavate the entire section with a shield machine.

  Under such circumstances, as a method of widening the cross section of the shield tunnel, a pipe roof is used to support a straight or curved pipe called a pipe roof to extend an existing shield tunnel or to integrate two shield tunnels. A plurality of small diameter shield tunnels called a construction method (Patent Document 1) or a roof shield are arranged along the tunnel axis direction so as to surround the junction of the main shield tunnel, and they are interconnected in the circumferential direction After that, a small cross section shield method (Patent Document 2) has been developed to excavate the inner region.

JP, 2010-43440, A JP, 2009-144463, A

  Although all these methods have been proven as shield tunnel cross-sectional widening methods, in the case of the pipe roof method, in order to construct the frame of the wide part called outer shell while excavating the inner region surrounded by the pipe roof, There is a tendency for a flood to occur or deformation of the ground with stress release, and in order to prevent this, the installation span of the pipe loop must be shortened, and there is a concern that the construction efficiency may be reduced.

  In addition, although the small cross section shield method constructs the outer shell by interconnecting a plurality of roof shields in the circumferential direction and then excavates the inner region of the outer shell, the work stability at the time of excavation is high, In order to connect the roof shields in the circumferential direction, it is necessary to cut open each roof shield, so when the diameter of the widening portion is large, the number of roof shields also increases and their cutting work increases, resulting in chemical injection The problem is that water blocking work such as freezing and the like becomes huge.

  The present invention has been made in consideration of the above-mentioned circumstances, and it is a large cross-section tunnel structure capable of reducing the work load at the time of cutting a shield tunnel while securing the work stability at the time of internal excavation by preceding construction of the outer shell. And it aims at providing the construction method.

  In order to achieve the above object, according to the large cross section tunnel structure according to the present invention, as described in claim 1, a cylindrical shield tunnel is formed such that its cylindrical central axis is substantially parallel to the tunnel axis and along the tunnel axis. A plurality of reinforced concrete rods are formed in each inner space of the plurality of cylindrical shield tunnels, and a plurality of adjacent cylindrical shield tunnels among the plurality of cylindrical shield tunnels are arranged adjacent to each other. A reinforced concrete frame for connection is constructed and connected to the reinforced concrete frame.

  In the large cross-section tunnel structure according to the present invention, as described in claim 2, the cylindrical shield tunnel is arranged in a row such that the central axis of the cylinder is substantially parallel to the tunnel axis and along the tunnel axis. A plurality of concrete shields are disposed to form a composite structure together with the steel segments constituting the cylindrical shield tunnel in each of the internal spaces of the cylindrical shield tunnel, and a plurality of the cylindrical shield tunnels are constructed. A connecting reinforced concrete frame is constructed and connected to the concrete box between two cylindrical shield tunnels adjacent to each other.

  In the large cross section tunnel structure according to the present invention, diameters of the plurality of cylindrical shield tunnels are changed along the tunnel axis.

  Further, in the large cross section tunnel structure according to the present invention, a branch and junction portion of a main tunnel and a lamp tunnel is provided in a space in the tunnel surrounded by the outer shell.

In the method for constructing a large cross section tunnel according to the present invention, as described in claim 5, in the rectangular shield machine, the longitudinal direction and the short side direction in the cross section are orthogonal to the tunnel axial direction of the large cross section tunnel respectively. A cylindrical shield tunnel is constructed by maintaining the posture substantially in line with the direction and making it orbit around the tunnel axis so as to surround the planned construction area of the large cross section tunnel,
A plurality of cylindrical shield tunnels are arranged in a row along the tunnel axis by repeating the winding process along the tunnel axis direction,
A reinforced concrete frame is constructed in each internal space of the plurality of cylindrical shield tunnels, and the opposing portions of two cylindrical shield tunnels adjacent to each other among the plurality of cylindrical shield tunnels are cut off and expanded between the opposing portions In the communication space where the ground is excavated and removed, a connecting reinforced concrete frame is constructed in a form to be continuous with the reinforced concrete frame, and the outer shell of the large cross section tunnel,
The ground which spreads to the inside of the outer shell is excavated and removed.

In the method for constructing a large cross section tunnel according to the present invention, as described in claim 6, in the rectangular shield machine, the longitudinal direction and the short direction in the cross section thereof are orthogonal to the tunnel axial direction of the large cross section tunnel respectively A cylindrical shield tunnel is constructed by maintaining the posture substantially in line with the direction and making it orbit around the tunnel axis so as to surround the planned construction area of the large cross section tunnel,
A plurality of cylindrical shield tunnels are arranged in a row along the tunnel axis by repeating the winding process along the tunnel axis direction,
A concrete casing is formed in each inner space of the plurality of cylindrical shield tunnels to form a composite structure together with the steel segments constituting the cylindrical shield tunnel, and two of the plurality of cylindrical shield tunnels are adjacent to each other A connecting reinforced concrete frame is constructed in a continuous space with the concrete body in a communication space formed by excavating and removing the ground part extending between the opposite parts of the two cylindrical shield tunnels, and the outside of the large cross section tunnel And
The ground which spreads to the inside of the outer shell is excavated and removed.

  Further, in the method of constructing a large cross-section tunnel according to the present invention, is it possible to form in advance a tunnel in parallel with the tunnel axis and to make the inner space of the tunnel a start reaching area for starting and reaching the rectangular shield machine? Alternatively, a work space is formed by excising and removing a part of the guide hole along the tunnel axis and excavating and removing a ground extending behind the tunnel and making the work space the start arrival area.

  Further, in the method of constructing a large cross section tunnel according to the present invention, in the winding step, a main push jack is installed in the start reaching area, and the rectangular shield machine and the subsequent segment row are pushed out by the main push jack. is there.

  Further, in the method of constructing a large cross section tunnel according to the present invention, when constructing the reinforced concrete frame, reinforcing bars are attached in advance to each of the segments constituting the segment row in the start reaching area.

  In the large cross section tunnel structure according to the first invention, a plurality of cylindrical shield tunnels are arranged in a row, and a reinforced concrete frame is constructed in each internal space of the plurality of cylindrical shield tunnels, and made continuous with the reinforced concrete frame. In the form, a connecting reinforced concrete frame is constructed as an outer shell between two cylindrical shield tunnels adjacent to each other.

  In the large cross section tunnel structure according to the second aspect of the present invention, a plurality of cylindrical shield tunnels are arranged in a row, and a concrete body is constructed in each inner space of the plurality of cylindrical shield tunnels. A connecting reinforced concrete frame is constructed as an outer shell between two cylindrical shield tunnels adjacent to each other in a continuous form. Here, the concrete body forms a composite structure similar to that of the concrete-filled steel pipe together with the steel segments that constitute the cylindrical shield tunnel.

  Further, in the method of constructing the large cross section tunnel according to the third and fourth inventions, first, the rectangular shield machine is wound around the tunnel axis line so as to surround the construction planned area of the large cross section tunnel. By repeating the winding process along the tunnel axis direction, a plurality of cylindrical shield tunnels are arranged in a row along the tunnel axis.

  Next, in the third invention, a reinforced concrete frame is constructed in each of the inner spaces of the plurality of cylindrical shield tunnels, and connection is made between two cylindrical shield tunnels adjacent to each other in a manner to be continuous with the reinforced concrete frame. For the fourth invention, a composite structure is formed together with the steel segments constituting the cylindrical shield tunnel in the inner spaces of a plurality of cylindrical shield tunnels. A concrete reinforced concrete structure is constructed between two cylindrical shield tunnels adjacent to each other so as to construct a concrete structure and to be continuous with the concrete structural body, thereby forming an outer shell of a large cross section tunnel.

  In this way, the operation of cutting the shield tunnel to construct the outer shell remains only at the opposite portion of the cylindrical shield tunnel, and the total extension thereof is the same as the tunnel section length compared to the conventional small cross section shield method. On the other hand, it is reduced to a fraction.

  In arranging a plurality of cylindrical shield tunnels in a row, how to set their diameter is arbitrary, and if it is made uniform along the tunnel axis, for example, a main line tunnel for road or railway use has a fixed length Although the configuration is suitable for construction with the same cross section, if the diameters of a plurality of cylindrical shield tunnels are changed along the tunnel axis, in the case of widening those main tunnels, for example, they are surrounded by an outer shell The configuration can be made suitable for the case where the main tunnel and the ramp tunnel are provided in the space inside the tunnel.

  The specific configuration of the rectangular shield machine is arbitrary as long as it is a shield machine capable of excavating the ground in a rectangular cross-sectional shape, and can be appropriately selected from known ones. It may be of a type that takes a reaction force from the segment and advances, or may be a so-called propulsion type type in which the assembly of the segment is not performed in the shield machine and the segment connected on the launch side advances with a push jack.

It is optional how to launch and reach the rectangular shield machine in rotating the rectangular shield machine, but a guideway is formed in advance in parallel with the tunnel axis and the start reach area is set using the guideway Is a typical example, and as a specific installation mode,
(a) Configuration in which the inner space of the tunnel is used as the arrival area
(b) Two aspects of a configuration in which a work space is formed by excavating and removing a part of the guide hole along the tunnel axis and excavating and removing the ground extending behind it, and using the work space as a start arrival area It is divided roughly.

Here, in the case where the main tunnel and the ramp tunnel are provided in the space in the tunnel of the large cross section tunnel, the configuration of (a) is further
(a-1) A structure in which the above-mentioned tunnel is a working tunnel constructed in parallel with the main tunnel and the ramp tunnel, and the inner space of the working tunnel is a start reaching area
(a-2) The above-mentioned guide hole is a lamp tunnel formed to extend to the small diameter side of a large cross-section tunnel, and the start and arrival of a rectangular shield machine with the inner space of the lamp tunnel as a start arrival area At least two aspects of the configuration performed on the small diameter side of the tunnel are subsumed. Here, in (a-2), it is sufficient for the lamp tunnel to extend to the large diameter side of the large cross section tunnel, and the main structure does not need to extend to the small diameter side. In such a case, the above-described configuration is made possible by using the lamp tunnel. The above-described configuration is not applicable at the cross-sectional position near the large diameter side because of the use of the internal space of the lamp tunnel.

Furthermore, in the configuration of (b),
(b-1) A construction in which the above-mentioned guide tunnel is used as a main tunnel or a ramp tunnel, and the work space formed by partially cutting off the guide tunnel is a start arrival area
(b-2) A large cross section of the rectangular shield machine with the above guide channel as a main line tunnel and a working space formed by partially cutting the guide channel at an arbitrary angular position as a start reach area At least two aspects of the configuration performed on the small diameter side of the tunnel are subsumed.

  Here, in the case of (b-1), since it is necessary to go around the rectangular shield machine so as to surround the main line tunnel and the lamp tunnel, the site where the main line tunnel or lamp tunnel is cut off as the guide hole is the main line. If it is a tunnel, it will be a side position opposite to the lamp tunnel, and if it is a lamp tunnel, it will be a side position opposite to the main tunnel.

  In the case of (b-2), it is sufficient to turn the rectangular shield machine so as to surround the main tunnel, so the site where the main tunnel as a guide hole is cut is not limited to the side position, but the upper position , Or any angle position such as the lower position.

  When the rectangular shield machine is to start and reach from the start and reach area, when the rectangular shield machine is to be circulated, the main push jack is installed in the start and reach area, and the main shield jack and the rectangular shield machine and its subsequent segment row By extruding, a cylindrical shield tunnel can be constructed.

  In particular, in the above configuration, reinforcing bars can be attached in advance to the segments that make up the segment row in the above-mentioned start reaching area, so that it is possible to greatly simplify the laying work when constructing the above-mentioned reinforced concrete frame. It becomes.

It is a figure of the large cross section tunnel structure 1 which concerns on this embodiment, (a) is a whole perspective view, (b) is a longitudinal cross-sectional view. The longitudinal cross-sectional view which showed the connection condition of the cylindrical RC housing 4a and the cyclic | annular RC housing 4b. It is the figure which showed the procedure of the construction method of the large cross section tunnel which concerns on this embodiment, and is the perspective view and the cross-sectional view which showed a mode that the start attainment area 32 was provided. It is the figure which showed the procedure of the construction method of the large cross section tunnel which concerns on this embodiment continuously, and the perspective view and the cross section which showed a mode that the cylindrical shield tunnel 2 was constructed by making the rectangular shield machine 33 go around. . It is the figure which showed the procedure of the construction method of the large cross section tunnel which concerns on this embodiment continuously, and the perspective view and horizontal cross section which showed a mode that construction of the cylindrical shield tunnel 2 was completed. It is the figure which showed the procedure of the construction method of the large cross section tunnel which concerns on this embodiment continuously, and is the longitudinal cross-sectional view which showed the connection procedure of the cylindrical RC rod 4a and the cyclic | annular RC rod 4b. The cross-sectional view which showed the modification of the lap | rotation process by a rectangular shield machine. The cross-sectional view which showed the modification of the start attainment area. The cross-sectional view which showed another modification of the start attainment area. The longitudinal section showing the modification of large section tunnel structure.

  Hereinafter, embodiments of a large cross section tunnel structure and a method of constructing the same according to the present invention will be described with reference to the attached drawings.

  FIG. 1 is a view showing a large cross section tunnel structure according to the present embodiment. As shown in the figure, in the large cross section tunnel structure 1 according to the present embodiment, the cylindrical shield tunnels 2 are arranged such that their cylindrical central axes are substantially parallel to the tunnel axis 3 of the large cross section tunnel. And a plurality of cylindrical RC rods 4a as reinforced concrete in the respective inner spaces of the plurality of cylindrical shield tunnels 2, and a plurality of cylindrical RC rods 4a are made continuous with the cylindrical RC rods 4a. Then, an annular RC body 4b as a connecting reinforced concrete frame is constructed between two cylindrical shield tunnels 2 and 2 adjacent to each other as an outer shell 5.

  Here, the cylindrical shield tunnels 2 have their diameters changed along the tunnel axis 3 so as to increase from the left side to the right side in the figure, and the in-tunnel space 6 surrounded by the outer shell 5 A branch junction of the main tunnel 7 and the lamp tunnel 8 disposed on the large diameter side (right side in the figure) is provided.

  FIG. 2 is a longitudinal sectional view showing the connection between the two cylindrical RC rods 4a and 4a and the annular RC rod 4b connecting them. As can be seen from the figure, the annular RC rod 4b is formed by cutting out the segments of the two cylindrical shield tunnels 2, 2 adjacent to each other, which are located opposite to each other, to form two cylindrical RC rods 4a, 4a. It is integrally formed to be continuous with the

  In order to construct the large cross section tunnel structure 1 according to the present embodiment, first, a plurality of cylindrical shield tunnels 2 are arranged in a row along the tunnel axis 3, one of the plurality of cylindrical shield tunnels 2 is The rectangular shield machine may be constructed one by one, or the planned section of the large cross section tunnel may be divided into several sections, and the cylindrical shield tunnel 2 may be divided by the rectangular shield machine for each section. It may be constructed.

  In order to construct the cylindrical shield tunnel 2, first, as shown in FIG. 3, the ground is improved by injecting a chemical solution or freezing to the ground spreading to the side of the main line tunnel 7 as a previously formed guide. A zone 31 is formed. In the following description, it is assumed that the construction proceeds from the cylindrical shield tunnel 2 disposed at a position relatively close to the large diameter side of the large-section tunnel, that is, the right side in FIG.

  Once the ground improvement zone 31 is formed, of the ground improvement zones, the central improvement zone 31a provided on the side of the main tunnel 7 secures water blocking while the segments constituting the main tunnel 7 are on its side While cutting along the tunnel axis 3 (see FIG. 1) at one position, excavating and removing the ground extending behind it to form a work space, the work space is taken with the start reaching area 32 of the rectangular shield machine described later. Do.

  Next, the rectangular shield machine 33 is installed in the start arrival area 32 and preparation for start is made.

  Next, the rectangular shield machine 33 is started from the start reaching area 32, and then, as shown in FIG. 4, the ground improvement zone 31 is stopped by the upper improvement zone 31b extended above the central improvement zone 31a. The cylindrical shield tunnel 2 is constructed by rotating around the tunnel axis 3 of the large cross section tunnel so as to surround the planned large area cross section construction region 42 while securing it.

  For example, a rectangular shield machine 33 having a width of about 10 to 15 m can be used.

  In winding, the rectangular shield machine 33 holds its posture so that the longitudinal direction and the short direction in the cross section of the rectangular shield machine 33 substantially coincide with the direction of the tunnel axis 3 of the large cross section tunnel and the direction orthogonal thereto, respectively. While assembling the segments at the tail of the machine, the reaction force may be taken from the segments to advance them.

  FIG. 5 shows that the construction of the cylindrical shield tunnel 2 is completed by rotating the rectangular shield machine 33 up to the start arrival area 32. In the start and arrival area 32, the space left behind the cylindrical shield tunnel 2 is filled with the backfill material 51.

  By repeating the winding process described above along the direction of the tunnel axis 3, a plurality of cylindrical shield tunnels 2 are arranged in a row along the tunnel axis. Here, the plurality of cylindrical shield tunnels 2 are constructed in a row at intervals of about 50 cm in order to construct an annular RC rod 4b therebetween.

  In the above example in which a plurality of cylindrical shield tunnels 2 are sequentially built from the large diameter side to the small diameter side of the large cross section tunnel, the rectangular shield machine 33 is configured each time one cylindrical shield tunnel 2 is finished. Then, it may be transferred sequentially to the small diameter side of the large cross section tunnel.

  On the other hand, a cylindrical RC tunnel 4a is constructed in the inner space of the cylindrical shield tunnel 2 which has been constructed, for example, sequentially from the cylindrical shield tunnel 2 located on the large diameter side of the large sectional tunnel. An annular RC rod 4b is constructed between two cylindrical shield tunnels 2 and 2 adjacent to each other to form an outer shell 5 of a large cross-section tunnel in a form continuous with the ring RC rod.

  FIG. 6 shows an example of the construction procedure of the cylindrical RC rod 4a and the annular RC rod 4b. As shown in the figure, in order to construct the cylindrical RC rod body 4a and the annular RC rod body 4b, first, as shown in FIG. On the other hand, the ground improvement zones 61, 61 are formed around the opposite part by applying a chemical solution injection or freezing method.

  The ground improvement zones 61, 61 are respectively formed in an annular shape so as to surround the opposing portions of the two cylindrical shield tunnels 2, 2 from the outside and the inside.

  On the other hand, in parallel with or simultaneously with this, the cylindrical RC rod body 4a is constructed in the inner space of the cylindrical shield tunnel 2 located on the right side in the same figure among the cylindrical shield tunnels 2 and 2. Here, since the cylindrical RC housing 4a is connected to the annular RC housing 4b in a later step, the connection space 62 on the side where the other cylindrical shield tunnel 2 is located in the internal space of the cylindrical shield tunnel 2 Build with leaving.

  Next, as shown in the figure (b), while securing water blocking by the ground improvement zone 61, the segment located at the opposing part of the cylindrical shield tunnels 2 and 2 is cut off, and between the opposing parts By excavating and removing the spreading ground, an annular communication space 63 is formed to communicate the inner spaces of the cylindrical shield tunnels 2 and 2.

  Next, as shown in FIG. 6C, of the cylindrical shield tunnels 2 and 2, in the internal space of the cylindrical shield tunnel 2 located on the right side in FIG. The remaining cylindrical RC rods 4a, the annular RC rods 4b in the communication space 63, and the cylindrical RC rods 4a in the internal space of the cylindrical shield tunnel 2 located on the left side are constructed.

  At this time, while appropriately using fixing bars and the like so that the cylindrical RC rod body 4a constructed in the connection space 62 is integrated with the existing cylindrical RC rod body 4a, the cylindrical RC rod body 4a constructed in the connection space 62, It is desirable to simultaneously carry out concrete casting so that the annular RC housing 4b and the left cylindrical RC housing 4a are continuously integrated with each other.

  In addition, when constructing the cylindrical RC body 4a in the internal space of the cylindrical shield tunnel 2 on the left side, a connection space 62 (not shown) is left as in the case of the cylindrical shield tunnel 2 on the right side.

  Thus, while constructing the cylindrical RC rod body 4a in the inner space of each cylindrical shield tunnel 2 respectively, the annular RC rod body 4b is formed between the cylindrical shield tunnels 2 and 2 adjacent to each other in a form continuous with them. Once the construction of the outer shell 5 is completed by construction, next, the space inside the outer shell 5 is formed with the tunnel space 6 by excavating and removing the ground extending inside the outer shell 5.

  As described above, according to the large cross section tunnel structure and the method of constructing the same according to the present embodiment, the shield tunnel cutting work for constructing the outer shell 5 is performed only at the opposing portions of the cylindrical shield tunnels 2 and 2. As it is sufficient, the total extension is reduced to a fraction of the same section length as compared to the conventional small cross section shield method.

  For example, when the diameter of the small diameter side of the large cross section tunnel is 15 m, the diameter of the large diameter side is 30 m, and the section length is 300 m, the number of shields is about 16 in the conventional small cross section shield method using a 3 m diameter roof shield. Since (15 m × π / 3) is required, the cut-and-open extension is 4,800 m (300 m × 16), whereas in the present embodiment, assuming that the width of the rectangular shield machine 33 is 15 m, the cylindrical shield tunnel The average diameter of 2 is 22.5 m ((15 m + 30 m) / 2), so the average circumference is 70.7 m (22.5 m × π), and the number of opposing parts of the cylindrical shield tunnel 2 is 19 (300 m / 15 m − Since it is 1), the cut-and-open extension is limited to 1,343 m (70.7 m × 19), which makes it possible to reduce 3,456.7 m in comparison with the conventional small cross section shield method.

  Therefore, the water blocking operation such as chemical solution injection and freezing is also greatly reduced, and thus, while securing the operation stability at the time of the internal excavation by the previous construction of the outer shell 5, the operation load at the time of opening the shield tunnel is significantly increased. Can be reduced.

  In the present embodiment, the branching and joining portion of the main tunnel 7 and the ramp tunnel 8 is provided in the space 6 in the tunnel surrounded by the outer shell 5, but the application of the large cross section tunnel structure is the branching and joining as described above. The present invention is not limited to the section, and is applicable to the junctions and junctions between main tunnels, and is not limited to road tunnels and railway tunnels in the first place, for example, when constructing a flood control facility of underground rivers It is possible to apply the present invention to

  Further, in the present embodiment, the diameter of the cylindrical shield tunnel 2 is changed, but if it is not necessary to widen the main tunnel 7, a plurality of cylindrical shield tunnels having the same diameter may be arranged in a row It does not matter.

  That is, even when there is no target for widening such as a main tunnel, a tunnel space with a large cross section can be formed by arranging a plurality of cylindrical shield tunnels of the same diameter in a row, in which case There is no change in that the same effects as those described above are exhibited.

  Further, in the present embodiment, it is assumed that the rectangular shield machine 33 is of a type in which a segment is assembled with its tail portion and reaction force is taken from the segment to move forward, but instead, from the rectangular shield machine 33 The rectangular shield machine according to the present invention is the one obtained by removing the electer, and the rectangular shield machine is driven forward by the main push jack 62 installed in the start reach area 32 together with the subsequent segment row 64 as shown in FIG. Can be configured to

  Here, if reinforcing bars 63 are attached in advance to each segment 61 constituting the segment row 64 in the start arrival area 32, it is possible to greatly simplify the laying operation when constructing the cylindrical RC chassis 4a. Become.

  Further, in the present embodiment, the main line tunnel 7 is used as a tunnel, its lateral position is cut along the tunnel axis 3, and a ground is expanded and removed behind it to form a working space, thereby forming the work Although the space is set as the start arrival area 32 of the rectangular shield machine 33, instead of the main line tunnel 7, as shown in FIG. 8A, the lamp tunnel 8 is used as a guide and the start arrival area is set as in the above embodiment. You may install 32b.

  Also, these are all configurations corresponding to (b-1) described above, but instead, configurations corresponding to (b-2), ie, main tunnel 7 as shown in FIG. The work space is a rectangular shield machine 33 by forming a working space by excavating and removing the ground extending behind it along with cutting a part of it along the tunnel axis 3 at an arbitrary angular position. It does not matter as the start arrival area 32c.

  In this configuration, it is sufficient to turn the main line tunnel 7, so the start reaching area 32c has a side position as shown in the figure, and an arbitrary angle such as an upper position, a lower position or an opposite side position. While being able to be installed in position, the applied cross-sectional position is limited to the small diameter side of the large cross section tunnel.

  In addition, in these modifications and the above-described embodiment, the configuration corresponding to the above-described (b), that is, excavating and removing the ground that extends behind the excavated part of the tunnel along the tunnel axis Instead of this, the work space is formed as the start arrival area, but instead of this, the construction of (a), ie, the construction where the inner space of the tunnel is used as the start arrival area is adopted. It does not matter.

  In FIG. 9 (a), a work tunnel 91 is constructed in parallel with the main line tunnel 7 and the lamp tunnel 8, and the work tunnel is used as a tunnel, and the rectangular shield machine 33 is started to reach from the inner space of the work tunnel. The configuration is shown and corresponds to the above (a-1).

  Further, FIG. 9 (b) shows a configuration in which the lamp tunnel 8 extended to the small diameter side of the large cross section tunnel is used as a guide and at the same time the rectangular shield machine 33 is launched and reached from the internal space of the lamp tunnel. And corresponds to the above (a-2).

  The lamp tunnel 8 is originally sufficient to extend to the large diameter side of the large cross section tunnel, and although it is not necessary to extend to the small diameter side as a main structure, it is extended to the small diameter side as a guideway. In such a case, the above-described configuration is made possible by using the lamp tunnel. Note that the above-described configuration is not applicable at the cross-sectional position near the large diameter side because the internal space of the lamp tunnel 8 is used.

  Moreover, in the present embodiment, while constructing the cylindrical RC rod body 4a as a reinforced concrete rod body in each internal space of the cylindrical shield tunnel 2, two cylindrical members adjacent to each other in a form to be continuous with the cylindrical RC rod body 4a. Although an annular RC body 4b as a reinforced concrete frame for connection is constructed between the shield tunnels 2 and 2 to form the outer shell 5, instead of this configuration, as shown in FIG. 10, each inner side of the cylindrical shield tunnel 2 Between the two cylindrical shield tunnels 2 and 2 adjacent to each other in a form to construct a concrete housing 104a forming a composite structure together with the steel segments constituting the cylindrical shield tunnel in a space and making it continuous with the concrete housing It is also possible to construct an annular RC body 104b as a reinforced concrete body for connection as the outer shell 5 .

  In this case, for example, by fixing the reinforcing bars embedded in the annular RC rod 104b to the concrete rod 104a, the continuity between the annular RC rod 104b and the concrete rods 104a and 104a is ensured.

1 Large cross section tunnel structure 2 Cylindrical shield tunnel 3 Tunnel axis of large cross section tunnel 4a Cylindrical RC frame (reinforced concrete box)
4b Annular RC body (Reinforced concrete body for connection)
Reference Signs List 5 outer shell 6 tunnel interior 7 main tunnel 8 ramp tunnel 32, 32b, 32c start arrival area 33 rectangular shield machine 61 segment 62 main push jack 63 rebar 64 segment row 91 work tunnel 104a concrete frame 104b annular RC frame (for connection Reinforced concrete frame)

Claims (9)

A plurality of cylindrical shield tunnels are arranged such that their cylindrical central axis is substantially parallel to the tunnel axis and in a row along the tunnel axis, and reinforced concrete rods are provided in the interior spaces of the plurality of cylindrical shield tunnels. And forming a connection reinforced concrete frame between the two cylindrical shield tunnels adjacent to each other among the plurality of cylindrical shield tunnels so as to construct a connection reinforced concrete frame as an outer shell. Large cross section tunnel structure. A plurality of cylindrical shield tunnels are arranged in such a way that their cylindrical central axis is substantially parallel to the tunnel axis and in a row along the tunnel axis, and the cylinders are placed in the interior spaces of the plurality of cylindrical shield tunnels. Form a concrete frame that forms a composite structure with the steel segments that make up the tubular shield tunnel, and of being continuous with the concrete chassis between two cylindrical shield tunnels adjacent to each other among the plurality of cylindrical shield tunnels A large cross-section tunnel structure characterized by the construction of a reinforced concrete frame for connection and the outer shell. The large cross-section tunnel structure according to claim 1 or 2, wherein diameters of the plurality of cylindrical shield tunnels are changed along the tunnel axis. 4. The large cross-section tunnel structure according to claim 3, wherein a branch junction of a main line tunnel and a lamp tunnel is provided in a space in the tunnel surrounded by the outer shell. The rectangular shield machine is held so that the longitudinal direction and the lateral direction in the cross section thereof substantially coincide with the tunnel axis direction of the large cross section tunnel and the direction orthogonal thereto, respectively, to surround the planned area of the large cross section tunnel. Construct a cylindrical shield tunnel by rotating it around its tunnel axis,
A plurality of cylindrical shield tunnels are arranged in a row along the tunnel axis by repeating the winding process along the tunnel axis direction,
A reinforced concrete frame is constructed in each internal space of the plurality of cylindrical shield tunnels, and the opposing portions of two cylindrical shield tunnels adjacent to each other among the plurality of cylindrical shield tunnels are cut off and expanded between the opposing portions In the communication space where the ground is excavated and removed, a connecting reinforced concrete frame is constructed in a form to be continuous with the reinforced concrete frame, and the outer shell of the large cross section tunnel,
A method for constructing a large cross section tunnel, comprising excavating and removing a ground extending inside the outer shell. The rectangular shield machine is held so that the longitudinal direction and the lateral direction in the cross section thereof substantially coincide with the tunnel axis direction of the large cross section tunnel and the direction orthogonal thereto, respectively, to surround the planned area of the large cross section tunnel. Construct a cylindrical shield tunnel by rotating it around its tunnel axis,
A plurality of cylindrical shield tunnels are arranged in a row along the tunnel axis by repeating the winding process along the tunnel axis direction,
A concrete casing is formed in each inner space of the plurality of cylindrical shield tunnels to form a composite structure together with the steel segments constituting the cylindrical shield tunnel, and two of the plurality of cylindrical shield tunnels are adjacent to each other A connecting reinforced concrete frame is constructed in a continuous space with the concrete body in a communication space formed by excavating and removing the ground parts extending between the opposite parts of the two cylindrical shield tunnels, and the outside of the large cross section tunnel And
A method for constructing a large cross section tunnel, comprising excavating and removing a ground extending inside the outer shell. A guide hole is formed in advance parallel to the tunnel axis, and an inner space of the guide hole is used as a start reaching area for starting and reaching the rectangular shield machine, or a part of the guide hole is along the tunnel axis. 7. The method according to claim 5, wherein a work space is formed by excavating and removing a ground that is excavated and expanded behind the work area, and the work space is used as the start reaching area. 8. The method for constructing a large cross section tunnel according to claim 7, wherein in the winding step, a main push jack is installed in the start reaching area, and the rectangular shield machine and the subsequent segment row are pushed out by the main push jack. 9. The method for constructing a large cross section tunnel according to claim 8, wherein when constructing the reinforced concrete frame, reinforcing bars are attached in advance to each segment constituting the segment row in the start reaching area.

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