JP4986044B2 - Shield tunnel opening reinforcement method - Google Patents

Description

  The present invention relates to a method for reinforcing an opening formed in a shield tunnel.

  Generally, in a shield tunnel, a segment as a primary lining member is designed to handle loads such as earth pressure and water pressure acting on the tunnel. Therefore, when selecting the type of segment to be used, carefully consider the strength, deformation performance, durability, economy, etc. in consideration of the covering of the target tunnel, the size of the water pressure, and the application. It becomes important. Among them, reinforced concrete segments (hereinafter referred to as “RC segments”) are often adopted from large economic sections in tunnels with large cross sections such as road tunnels. In a tunnel having a general upper and lower two lane cross section, as shown in FIG. 9, evacuation passages 60 that connect the upper and lower lines at intervals of about 500 m are provided due to disaster prevention regulations and the like. The evacuation passage 60 plays the role of evacuating road users from the disaster tunnel side to the non-disaster tunnel side when a fire or accident occurs in the tunnel.

As for the design of the segment, a conventional method is often used in which the calculation is performed on the acting force in the transverse direction of the tunnel on the assumption that the ring has a uniform bending rigidity. However, in the shield tunnel 50 in which the opening is formed, a cross-sectional defect occurs in the ring, and the stress generated in the segment near the opening increases due to stress concentration caused by the cross-sectional defect. Therefore, as shown in FIG. 10, a steel segment having a high material strength is often used in a predetermined section in the axial direction of the shield tunnel 50 around the opening 16. Further, Patent Document 1 proposes a segment technology that eliminates the use of dedicated parts as much as possible for the purpose of reducing the cost of supporting work in the tunnel opening.
JP-A-2005-213851

  In general, the steel segment costs about three times as much as the RC segment, and the use of the steel segment leads to an increase in segment cost. In addition, the steel segment needs to be protected against rust, and secondary lining such as decorative concrete and sprayed concrete must be applied to block contact with the outside air. As a result, construction costs have also increased.

In addition, when the opening is reinforced using the support described in Patent Document 1, a columnar support is installed inside the tunnel, so that the internal space is narrowed, particularly when the tunnel diameter is small, the work is hindered. It was.

The present invention has been made in order to solve such problems, and a shield that has been conventionally lined with a steel segment by simply reinforcing the opening formed in the shield tunnel. An object of the present invention is to provide a shield tunnel opening reinforcement method that can be implemented by lining with an RC segment around the tunnel opening.
It is another object of the present invention to provide a shield tunnel opening reinforcing method that does not hinder the work by supporting works arranged around the tunnel opening.

To achieve the above object, a shield tunnel opening reinforcing method according to the present invention includes an opening formed in a shield tunnel composed of a lining segment assembled in a ring shape, the opening, and a peripheral reinforcing portion. A removable opening segment is incorporated into the area, an opening reinforcing support is built around the opening segment, the opening segment is removed to form a segment opening, and a peripheral edge reinforcing portion of the segment opening Further, a frame-like reinforcing member made of an assembled steel material having a thickness equal to or less than the thickness of the lining segment is provided, and then the opening reinforcing support is removed.

  Further, in the shield tunnel opening reinforcing method according to the present invention, the opening reinforcing support is formed by assembling a plurality of circumferential supports and reinforcing beams installed along the inner peripheral surface of the lining segment. You may comprise as follows.

  In the shield tunnel opening reinforcing method according to the present invention, the width of the lining segment and the opening segment is determined based on a range including the opening and a peripheral reinforcing portion of the opening. You may comprise.

  The shield tunnel opening reinforcing method according to the present invention may be configured such that the lining segment is an RC segment and the opening segment is a steel segment.

As described above, according to the present invention, by simply reinforcing the opening formed in the shield tunnel, the RC segment can be used in the vicinity of the shield tunnel opening conventionally covered with the steel segment. . As a result, there is an effect that the cost of the segment can be suppressed and the secondary lining process necessary for the rust prevention of the steel segment can be eliminated.
Further, by using a circumferential support or a segment in which a reinforcing material is previously incorporated, an effect is obtained that a working space can be ensured as compared with a conventional construction method.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the best mode for carrying out a shield tunnel opening reinforcing method according to the present invention will be described below with reference to the accompanying drawings.

  A method for reinforcing an opening of a shield tunnel according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 5 are step diagrams of the method for reinforcing the opening of the shield tunnel.

FIG. 1 shows the vicinity of an opening of a shield tunnel in which a segment 40 is lined by the excavation of a shield machine, (a) is a partial longitudinal sectional view seen from the inner periphery of the tunnel, and (b) is a diagram (a). It is the cross-sectional view shown by the Ib-Ib sectional line in the inside.
The range marked with dots indicates the steel segment 11 (opening segment), and the other segments indicate the RC segment 12 (lining segment). Each segment 40 is connected in the tunnel circumferential direction and the axial direction, and a shield tunnel in which the ring 10 is continuous in the axial direction is constructed. When assembling the segment opening 16 (FIG. 3) with the segment 40, the area where the shield tunnel opening and the opening reinforcing member 17 (FIG. 4) to be described later are formed is assembled with the steel segment 11. The adjacent RC segments 12 are firmly fastened with connecting bolts, while the steel segment 11 is detachably fastened with the adjacent segment 40. In order to facilitate the removal of the steel segment 11, for example, it is preferable to increase the size of a bolt box installed in the segment 40 or to select a hexagonal bolt as a connecting bolt.

  The width of the segment 40 is determined so that the dimension of the opening reinforcing member 17 (FIG. 4) described later is minimized. In this embodiment, the segment width W is set to a length obtained by dividing the range required for the installation of the shield tunnel opening 18 (FIG. 4) and the opening reinforcing member 17 (FIG. 4) into two equal parts.

  In general, the ring 10 constituting the shield tunnel is assembled by shifting the joint position for each ring in order to reduce the influence of the rigidity of the joint portion. However, the ring 10 including the steel segment 11 takes into consideration the shape of the opening 18 (FIG. 4) and the opening reinforcing member 17 (FIG. 4), or of an arch-shaped support 20 (FIG. 2) described later. In consideration of installation, it is desirable to provide joints at the same location (so-called potato splicing).

  When the segment 40 is assembled by the excavation of the shield machine, the back void is injected into the tail void. As the backfilling injection material, cement is used as the main material and various admixtures are kneaded. The backfill injection is injected from the injection hole (not shown) installed in the segment 40 into the gap with the natural ground, or directly from the rear end of the tail plate (not shown) behind the shield machine toward the tail void, or these Infused in combination.

  FIG. 2 shows the vicinity of the opening of the shield tunnel in which the support work 20 is installed on the inner periphery of the tunnel, (a) is a partial longitudinal sectional view as seen from the inner periphery of the tunnel, and (b) is in FIG. It is the cross-sectional view shown by the IIb-IIb cross section line. After completion of tail void backfill injection, a support 20 is installed around the opening. The support work 20 plays a role of preventing deformation of the shield tunnel due to earth pressure or water pressure by receiving a load that the steel segment 11 to be removed, which will be described later, takes on. The support 20 includes an arc-shaped support 13 in which H-shaped steel is bent along the inner peripheral surface of the segment 40, a substantially C-shaped support 15, and a shaft of a tunnel in the vicinity of two opposite sides of the opening. It is constructed by assembling a beam member support work 14 made of square steel arranged in parallel with the direction. The arc-shaped support 13 is disposed at a predetermined distance from the end of the opening across the opening, and is connected to the beam member support 14 so as to surround the opening together with the beam member support 14. There is no. Further, four substantially C-shaped support members 15 having beam member support members 14 connected to the end portions are arranged at substantially equal intervals. In this embodiment, the beam member support 14 uses square steel in consideration of the relationship with the arc-shaped support. In addition, as for the support work 20, the dimension of each member, the installation interval, etc. are determined so that a deformation | transformation of a tunnel can be prevented from the earth pressure, water pressure, etc. which act on a shield tunnel. By adopting the above-described circumferential support, it is possible to secure a work space as compared with the conventional method, and it is possible to support in a balanced manner.

FIG. 3 shows the vicinity of the opening of the shield tunnel from which the steel segment 11 has been removed from the state shown in FIG. 2, (a) is a partial longitudinal sectional view as seen from the inner periphery of the tunnel, and (b) is (a) FIG. 3 is a cross-sectional view taken along the line IIIb-IIIb in the figure.
As described above, after the support work 20 is assembled in the vicinity of the opening of the shield tunnel, the steel segment installed in the segment opening 16 is removed.

FIG. 4 shows the vicinity of the opening of the shield tunnel in which the opening reinforcing member 17 is installed in the segment opening 16 (FIG. 3) from the state shown in FIG. 3, and (a) is viewed from the inner periphery of the tunnel. FIG. 4B is a partial longitudinal sectional view, and FIG. 4B is a transverse sectional view taken along the IVb-IVb sectional line in FIG.
In the segment opening 16 from which the steel segment has been removed, an opening reinforcing member 17 made of a steel material having a thickness equal to or less than that of the RC segment 12 is disposed, and an opening 18 is formed. The opening reinforcing member 17 is fastened with bolts to the RC segment 12 forming the segment opening 16 (FIG. 3) having a bolt box (not shown). Since the RC segment 12 is formed with a predetermined curvature in the circumferential direction of the shield tunnel, the opening reinforcing member 17 disposed in the circumferential direction is also bent with the same curvature. Moreover, the opening part reinforcement material 17 is designed with respect to the acting force to the opening part generated when the support work 20 assembled around the opening part is removed. If the opening reinforcing member 17 is assembled in advance at the factory, it is convenient because it does not take time and labor on site.

5 shows a shield tunnel from which the support work 20 has been removed from the state shown in FIG. 4, wherein (a) is a partial longitudinal sectional view as seen from the inner periphery of the tunnel, and (b) is in FIG. It is the cross-sectional view shown by the Vb-Vb cross section line.
If the opening part reinforcement material 17 is installed, the support work 20 arrange | positioned in the opening part vicinity will be removed. The newly installed opening reinforcement member 17 can receive the load that the supporter 20 has taken over.

  Conventionally, when an opening is formed in a shield tunnel, an expensive steel segment is often used as a segment disposed in the vicinity of the opening. However, according to the configuration described above, the segment in the vicinity of the opening can be the RC segment, and the range of use of the steel segment can be greatly reduced. As a result, segment costs can be significantly reduced.

  Moreover, since the thickness of the opening reinforcing material is set to be equal to or less than the thickness of the RC segment, the opening reinforcing material does not protrude to the inside of the tunnel without partially widening the opening. Therefore, since the opening may have an excavation cross section having the same size as the general portion, economical shield excavation is possible.

  Further, since the support installed in the vicinity of the opening is removed after the reinforcement of one opening is completed, the support at the time of the support pattern having the strictest design conditions can be used for other openings. Therefore, particularly when there are many evacuation passages to be built, economical construction is possible.

  The above-mentioned materials and the number of support works can be considered in various forms depending on the design conditions determined by the type of ground around the tunnel, groundwater level, soil cover, and the like. The same applies to the opening reinforcing material, and is not limited to the above-described reinforcing method.

  In the above-described embodiment, a steel segment is installed at the opening of the original shield tunnel. This is because the steel segment can be easily removed, it can be repeatedly used, and handling is good. Therefore, the present invention is not limited to the steel segment, and other types of segments (for example, an RC segment) may be disposed in the tunnel opening.

  In the above-described embodiment, a method was described in which a steel segment was incorporated in an opening and a support member was assembled in the vicinity of the opening and then the opening reinforcement was installed. Hereinafter, a second embodiment which is another embodiment will be described with reference to FIGS. 6 to 7 are step diagrams of the method for reinforcing the opening of the shield tunnel.

  FIG. 6 shows the vicinity of the opening of the shield tunnel in which the segment 40 is lined by the shield machine, (a) is a partial longitudinal sectional view seen from the inner periphery of the tunnel, and (b) is (a) FIG. It is the cross-sectional view shown by the VIb-VIb sectional line in the inside. The range in which dots are formed in the figure indicates the steel segment 30 (opening segment), and the other segments indicate the RC segment 12 (lining segment). Each segment 40 is connected to each other in the tunnel circumferential direction and the axial direction to form the ring 10. Similar to the first embodiment, the segment width W is set with reference to a width obtained by dividing the size required for the opening of the shield tunnel and the opening reinforcing material into two equal parts. Also, adjacent rings 10 including the segment openings are provided with joints at the same location.

  FIG. 8 shows a detailed view of the steel segment 30 of the second embodiment, where (a) is a plan view seen from the inner periphery of the tunnel, and (b) is a cross-sectional line VIIIb-VIIIb in FIG. It is sectional drawing shown, (c) is the top view which decomposed | disassembled the steel segment 30 into two members.

  The steel segment 30 of the present embodiment includes an opening reinforcing segment 31 and an opening segment 32 and is fastened to the adjacent RC segment 12. The opening reinforcing segment 31 is made of a U-shaped cut steel material and is formed with a predetermined curvature according to the shape of the tunnel in the circumferential direction. The opening segment 32 is made of a box-shaped assembled steel material in which four sides of a bottom steel plate 33 processed to a predetermined curvature are surrounded by side steel plates 34 and the internal space is reinforced by reinforcing ribs 35. The opening reinforcing segment 31 and the opening segment 32 are fastened by a bolt 37. The bottom steel plate 33 is formed with one injection hole 36 for backfill injection. The opening reinforcing segment 31 is designed with respect to a load acting on the opening. Note that the thickness of the steel segment 30 is set to be equal to or less than the thickness of the RC segment 12.

  When the segment 40 is assembled by the excavation of the shield machine, the backfilling injection material is injected from the injection hole 36 in the steel segment 30.

  FIG. 7 shows the periphery of the opening of the shield tunnel from which the opening segment 32 (FIG. 8) of the steel segment 30 has been removed from the situation shown in FIG. 6, and (a) is a partial longitudinal sectional view as seen from the inner periphery of the tunnel. (B) is the cross-sectional view shown by the VIIb-VIIb sectional line in (a) figure. When the backfill injection is complete, the open segment 32 of the steel segment 30 is removed. The load carried by the opening segment 32 can be received by the opening reinforcing segment 31 (FIG. 8) of the steel segment 30 and the shield tunnel can be stabilized.

  Even in the above-described second embodiment, the effect of the present invention shown in the first embodiment can be enjoyed. Furthermore, the installation of the support work 20 installed in the vicinity of the opening shown in the first embodiment is not required, and the amount of work at the site is reduced. Can be reduced.

Schematic of the vicinity of the opening of the shield tunnel. FIG. 2 is a schematic view of the vicinity of an opening of a shield tunnel where a support work is installed from the situation shown in FIG. 1. Schematic diagram of the vicinity of the opening of the shield tunnel with the opening segment removed from the state shown in FIG. The schematic of the opening part vicinity of the shield tunnel by which the opening part reinforcement material was installed in the opening part from the state shown in FIG. Schematic of the vicinity of the opening part of the shield tunnel from which the support work near the opening part was removed. The schematic of the opening part vicinity of the shield tunnel by another Example (Example 2). FIG. 7 is a schematic view of the vicinity of the opening of the shield tunnel from which the opening segment is removed from the state shown in FIG. 6. FIG. 5 is a detailed view of a steel segment of Example 2. Schematic diagram of a conventional shield tunnel with two upper and lower lanes. Schematic of the periphery of an opening formed in a conventional shield tunnel.

Explanation of symbols

10 Ring 11 Steel segment (opening segment)
12 RC segment (lining segment)
DESCRIPTION OF SYMBOLS 13 Arc-shaped support 14 Beam member support 15 Substantially C-shaped support 16 Segment opening 17 Opening reinforcement 18 Opening 20 Supporting 30 Steel segment (opening segment)
31 Opening Reinforcing Segment 32 Opening Segment 33 Bottom Steel Plate 34 Side Steel Plate 35 Reinforcing Rib 36 Injection Hole 37 Bolt 40 Segment 50 Shield Tunnel 60 Evacuation Path W Segment Width

Claims (4)

A removable opening segment is incorporated in a range including an opening formed in a shield tunnel composed of a lining segment assembled in a ring shape, the opening, and a peripheral reinforcing portion, and an opening is formed around the opening segment. A reinforcement support is built in, the opening segment is removed to form a segment opening, and a frame-shaped reinforcing member made of an assembled steel material having a thickness equal to or less than the thickness of the lining segment is formed on the peripheral edge of the segment opening. A method for reinforcing an opening of a shield tunnel, comprising: providing and then removing the opening reinforcing support. 2. The shield tunnel opening according to claim 1, wherein the opening reinforcing support is formed by assembling a plurality of circumferential supports installed along the inner peripheral surface of the lining segment and reinforcing beams. 3. Reinforcement method. 3. The shield tunnel according to claim 1, wherein the width of the lining segment and the opening segment is determined based on a range including the opening and a peripheral reinforcing portion of the opening. How to reinforce the opening. The shield tunnel opening reinforcing method according to any one of claims 1 to 3, wherein the lining segment is an RC segment, and the opening segment is a steel segment.

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