JP2017002721A - Tunnel guide member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optimal inclination angle of a guide cylinder and a forepoling steel pipe in tunnel boring by AGF method.SOLUTION: A guide member 3 is disposed on a guide-attached arch timbering 10A which intersects a base end part of a forepoling steel pipe 9 on rear side of boring in a tunnel 1. A guide cylinder 30 that penetrates the arch timbering 10A is formed on the guide member 3. The arch timbering 10A supports the guide cylinder 30 by a support part 20. The guide cylinder 30 is made to incline toward an outer peripheral side of the tunnel 1 at θ=4 to 10 degrees to a tunnel axis line Lwith approaching front side of boring of the tunnel 1. The forepoling steel pipe 9 is inserted in the guide cylinder 30. Thus, the inclination angle θof the forepoling steel pipe 9 follows the angle θof the guide cylinder 30.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a guide member used for a tunnel, and more particularly to a guide member for guiding a receiving steel pipe when the receiving steel pipe is driven in a so-called AGF (All Ground Fasten) method.

  For example, Patent Document 1 discloses an AGF method as a method for excavating a tunnel by mechanical digging. This method is to reinforce the natural ground by driving a long steel pipe into the natural ground ahead of the face. The proximal end of the receiving steel pipe on the rear side of the excavation intersects the arch support with the guide member. A guide cylinder of the guide member passes through the web of the arch support work. The axis of the guide tube is inclined obliquely outward toward the front of the tunnel.

  A protective pipe is passed through the guide tube. Further, the receiving steel pipe is inserted into the protective pipe and driven into a natural ground by a drill jumbo (a receiving steel pipe placing device). The receiving steel pipe is inclined obliquely outward toward the front of the tunnel along the axis of the guide cylinder. The driving angle of the receiving steel pipe can be adjusted by the inclination angle of the guide tube.

Japanese Patent No. 3094155

In Patent Document 1, it is described that the driving angle of the receiving steel pipe is set to a minimum angle close to horizontal ([Claim 6]), but a specific numerical value of the angle is not disclosed. There is no description about the value of the inclination angle of the guide tube.
In view of the above circumstances, an object of the present invention is to present a preferable inclination angle of a guide tube and, in turn, a preferable inclination angle of a leading steel pipe in tunnel excavation by the AGF method.

In order to solve the above problems, the present invention is a tunnel guide member provided in a guided arch support that intersects with a base end portion (an end portion on the rear side of excavation) of a receiving steel pipe in a tunnel,
A guide tube that penetrates the guided arch support and through which the steel pipe is inserted;
A support portion for supporting the guide tube on the guided arch support,
The guide cylinder is inclined 4 ° to 10 ° with respect to the tunnel axis toward the outer peripheral side of the tunnel toward the tunnel excavation front side.

By inserting the receiving steel pipe into the guide cylinder, the driving angle of the receiving steel pipe can be made to follow the inclination angle of the guide cylinder. Thereby, the extending direction of the receiving steel pipe can be made as close as possible to the direction parallel to the tunnel axis, and the excavation cross section can be made as small as possible. And a pre-receiving steel pipe can be arrange | positioned at the arch support work which is installed next. Even if the receiving steel pipe is short, the receiving steel pipes adjacent to each other in the front and rear direction in the excavation direction can be overlapped to ensure the effect of reinforcing the natural ground, and stable tunnel excavation can be performed.
The inclination angle of the guide tube is more preferably 6 ° to 8 °.

  ADVANTAGE OF THE INVENTION According to this invention, in tunnel excavation by an AGF construction method, the suitable inclination angle of a guide cylinder and by extension, a tip receiving steel pipe can be shown.

FIG. 1 is a side cross-sectional view showing an embodiment of the present invention and a state in which a tunnel is dug. FIG. 2 is a front sectional view of the tunnel taken along line II-II in FIG. Fig.3 (a) is a front view of the guide cylinder used for tunnel construction. FIG.3 (b) is sectional drawing which follows the IIIb-IIIb line | wire of the figure (a). FIG. 3C is a perspective view of the guide tube. FIG. 4 is a side cross-sectional view around the face of the tunnel, showing a guide cylinder closing process in tunnel construction. FIG. 5 is a side cross-sectional view around the face of the tunnel, showing the step of placing the primary shotcrete. FIG. 6 is a side cross-sectional view of the periphery of the face of the tunnel, showing the blockage releasing process of the guide tube. FIG. 7 is a side cross-sectional view of the periphery of the face of the tunnel and the back side of the face, showing the step of driving the receiving steel pipe. FIG. 8 is a side cross-sectional view of the periphery of the face of the tunnel, showing an injection material injection process. FIG. 9 is a side cross-sectional view around the face of the tunnel, showing the step of placing the secondary shotcrete.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the tunnel 1 of the present embodiment is dug by a so-called AGF (All Ground Fasten) method. In the upper half portion of the tunnel ₁ , long leading steel pipes 9 are provided at regular intervals along the tunnel axis L ₁ . Previously receiving steel pipe 9 is driven excavation front side with respect to the tunnel axis L ₁ into the tunnel outer peripheral side toward the (right side in FIG. 1) at a predetermined angle theta ₉ to natural ground 2. As shown in FIG. 2, a plurality of receiving steel pipes 9 are arranged at intervals in the circumferential direction of the upper half of the tunnel 1.

As shown in FIG. 1, arch supporters 10 are provided in the tunnel 1 at regular intervals. Arrangement pitch _{P 10} of the arch支保Engineering 10, for example 0.8m~3m, preferably about 1 m. The arch support 10 extends in an arch shape along the circumferential direction of the tunnel 1 (FIG. 2), and the cross section is H-shaped (FIG. 4). As shown in FIG. 4, the flange width W ₁₀ of the arch support work 10 is, for example, about W ₁₀ = 100 mm to 300 mm, and preferably about W ₁₀ = 200 mm. Web height _{H 10} of the arch支保Engineering 10, for example _H 10 = _100mm~300mm about, preferably _H 10 = about 200 mm.

As shown in FIG. 1, a fixed number (for example, nine) of guided arch supports 10 </ b> A out of the arch supports 10 intersect with a base end portion of the receiving steel pipe 9 on the rear side of the excavation.
Among the arch supports 10, the rear adjacent arch support 10B adjacent to the digging rear side (the wellhead side, the left side in FIG. 1) of the guided arch support 10A is another arch support work such as the guided arch support 10A. It is higher than 10. As shown in FIG. 5, a bottom-up piece 15 is provided at the lower end of the rear adjacent arch support 10B.
In addition, as shown in FIG. 1, the shotcrete 50 is sprayed on the natural ground surface 2a between the arch supporting works 10 adjacent to each other. Further, as shown by a two-dot chain line in FIG. 2, lining concrete 53 is placed on the inner peripheral side of the tunnel from the shotcrete 50 and the arch support work 10.

  As shown in FIGS. 1 and 2, a guide member 3 is provided in the guided arch support 10A. A plurality of guide members 3 are arranged at intervals in the extending direction (circumferential direction of the tunnel 1) of each guided arch supporting work 10A. Using these guide members 3 as guides, the receiving steel pipe 9 is driven into the natural ground 2.

  As shown in FIG. 3, each guide member 3 includes a guide plate 20 (support portion) and a guide tube 30. The guide plate 20 is made of a steel plate. The guide plate 20 has a main plate portion 21 and reinforcing ribs 22, 23 and 24. The main plate portion 21 has a trapezoidal shape. Reinforcing ribs 22, 23, and 24 are provided on the four edges of the main plate portion 21, respectively. These reinforcing ribs 22, 23, 24 intersect the main plate portion 21 and protrude toward the rear side of the excavation. Reinforcing ribs 22 and 23 are formed by bending the upper and lower ends of the steel plate for the main plate portion 21 at a right angle. The side reinforcing ribs 24 are made of a steel plate different from the steel plate for the main plate portion 21 and are joined to the main plate portion 21 and the reinforcing ribs 22 and 23 by welding.

  As shown in FIG. 4, the main plate portion 21 is addressed to and welded to the web 11 of the guided arch support 10A. The upper reinforcing rib 22 is addressed to and welded to the upper flange 12 of the guided arch support 10A. The lower reinforcing rib 23 is addressed to and welded to the lower flange 13 of the guided arch supporting work 10A.

As shown in FIG. 3, a guide tube 30 is provided at the center of the main plate portion 21. The guide cylinder 30 is constituted by a steel pipe. The inner diameter of the guide tube 30 is slightly larger than the outer diameter of the pre-receiving steel pipe 9 (FIG. 7). The outer diameter or height H ₃₀ of the guide tube 30 is, for example, about H ₃₀ = 100 mm to 180 mm, preferably about 140 mm. As shown in FIG. 4, the guide cylinder 30 passes through the main plate portion 21 and the web 11. Through holes 21c and 11c for the guide tube 30 are formed in the main plate portion 21 and the web 11, respectively. A cross-sectional defect due to the through hole 11c of the web 11 is reinforced by the guide plate 20 (reinforcing plate). The guide tube 30 is supported by the guided arch support 10A via the guide plate 20 (support portion).

As shown in FIG.3 (b), the cylinder axis | shaft L30 of the guide cylinder ₃₀ is inclined diagonally upward toward the excavation front side. The inclination angle θ ₃₀ of the cylinder axis L ₃₀ with respect to the direction parallel to the tunnel axis L ₁ (left-right direction in FIG. 3B) is preferably about θ ₃₀ = 4 to 10 °, more preferably θ ₃₀ = 6. It is about 8 ° to 8 °. In the guide tube 30, the entry side tube portion 31 on the rear side of the digging from the main plate portion 21 is sufficiently shorter than the exit side tube portion 32 on the front side of the digging than the main plate portion 21. The entry side cylinder part length L ₃₁ projected onto the plane parallel to the tunnel axis L ₁ and the exit side cylinder part length L ₃₂ projected from the exit cylinder part 32 onto the plane parallel to the tunnel axis L _1. The ratio is preferably about L ₃₁ : L ₃₂ = 1: 8 to 1:12, and more preferably about L ₃₁ : L ₃₂ = 1: 10 to 1:11.

Tunnel 1 is constructed as follows.
The tunnel 1 is dug by excavating the natural ground 2 with an unillustrated excavator. Every time one pitch P ₁₀ minutes of the arch support 10 is dug, the arch support 10 is installed in the immediate vicinity of the face 1e. The shotcrete 50 is placed on the ground surface 2a between the arch support work 10 closest to the face and the arch support work 10 installed immediately before the work. Furthermore, the lining concrete 53 is constructed | assembled in the inner peripheral side of the shotcrete 50 in a post process.

Further, in the AGF method according to the present invention, the following steps are performed.
<Construction process of rear adjacent arch support 10B>
When constructing the rear adjacent arch supporting work 10B immediately before the guided arch supporting work 10A, a bottom raising piece 15 (FIG. 5) is provided on the floor surface of the tunnel 1. The rear adjacent arch support 10 </ b> B is placed on the bottom raising piece 15. As a result, the rear adjacent arch support work 10 </ b> B becomes higher than the other arch support work 10.
<Construction process of guided arch support 10A>
Next to the rear adjacent arch support 10B, a guided arch support 10A is constructed. That is, as shown in FIG. 1, every time the excavation of the tunnel 1 proceeds, for example, 9 meters (9 pitches P ₁₀ minutes of the arch support 10), instead of the normal arch support 10 (without the guide member 3), The guided arch support 10A is installed in the immediate vicinity of the face 1e.

<Blocking process of guide tube 30>
As shown in FIG. 4, a blocking member 60 is provided on the guide cylinder 30 of each guide member 3 of the guided arch supporting work 10 </ b> A. The guide tube 30 is closed by the closing material 60. Here, for example, a block of foamed polystyrene (foamed resin) is used as the closing material 60.
Alternatively, a film body made of a resin sheet, a nonwoven fabric, a woven fabric, or the like may be used as the closing material. A film-like blocking material may be placed on the inlet side cylinder portion 31 of the guide cylinder 30 and bound with a binding material such as a band. The membrane-like blocking material may be formed in a drawstring bag shape with a mouth strap.

<Placement process of primary sprayed concrete 51>
Subsequently, as shown in FIG. 5, the primary shotcrete 51 is placed on the natural ground surface 2 a between the rear adjacent arch support 10 </ b> B and the guided arch support 10 </ b> A. Prior to placing, the guide cylinder 30 is closed with the closing material 60, so that the primary spray concrete 51 can be prevented from entering the guide cylinder 30, and the guide cylinder 30 can be prevented from being clogged with the primary spray concrete 51. Preferably, the thickness of the primary shotcrete 51 is increased near the rear adjacent arch support 10B and decreased near the guided arch support 10A. More preferably, the thickness of the primary sprayed concrete 51 is gradually reduced as it approaches the guided arch support 10A. This can reliably prevent the primary sprayed concrete 51 from entering the guide tube 30. As a result, clogging of the guide tube 30 can be prevented more reliably.
In the primary sprayed concrete 51, a receiving steel pipe guide recess 51b is formed. The guide member 3 faces the end portion of the front receiving steel pipe guide recess 51b on the front side of excavation.

<Blockage release process of guide tube 30>
After placing the primary sprayed concrete 51, the blocking material 60 is removed from the guide tube 30 as shown in FIG. 6. Alternatively, the blocking material 60 may be destroyed. The film-like occlusion material may be torn or torn.
As a result, the closed state of the guide tube 30 is released, and the internal space of the guide tube 30 communicates with the internal space of the tunnel 1 through the pre-receiving steel pipe guide recess 51b.

<Punching process of the pre-receiving steel pipe 9>
Subsequently, as shown in FIG. 1, a pre-receiving steel pipe placing device 4 (drill jumbo) is installed in the tunnel 1 on the rear side of the cutting face 1 e. A guide cell 4c is provided at the tip of the boom 4b of the receiving steel pipe placing device 4, and a rod 4d is attached to the guide cell 4c. A leading steel pipe 9 is fitted on the outer periphery of the rod 4d. The tip of the rod 4d and the tip of the tip receiving steel pipe 9 are locked together.
Then, as shown in FIG. 7, the rod 4d and the tip receiving steel pipe 9 are inserted into the guide tube 30 from the tip receiving steel pipe guide recess 51b. As described above, by preventing the guide cylinder 30 from being clogged with the primary sprayed concrete 51, the receiving steel pipe 9 can be inserted into the guide cylinder 30 without any trouble.
Furthermore, the leading steel pipe 9 is driven to lead the lost bit 4e at the tip of the leading steel pipe 9 while leading the leading steel pipe 9 from the face 1e to the ground 2 on the front side of the excavation (the face behind the face). Type in. At this time, the guide tube 30 can guide the axis L ₉ of the receiving steel pipe 9 along the guide tube axis L ₃₀ . That is, the inclination angle θ ₉ with respect to the tunnel axis L ₁ (the left-right direction in FIG. 7) of the leading steel pipe 9 can follow the angle θ ₃₀ of the guide cylinder 30. Specifically, θ ₉ = 4 ° to 10 °, preferably θ ₉ = 6 ° to 8 °.
By raising the rear adjacent arch supporting work 10B to the bottom, the angle θ ₉ of the receiving steel pipe 9 is set while avoiding the tip of the boom 4b of the receiving steel pipe placing device 4 from interfering with the rear adjacent arch supporting work 10B. It can be within the numerical range.

After driving the receiving steel pipe 9, the rod 4d is pulled out. The leading steel pipe 9 is left in the natural ground 2.
<Injection process of injection material 8>
Next, as shown in FIG. 8, an injection material 8 is injected and filled in the first receiving steel pipe 9. The injection material 8 is preferably a silica resin-based injection material. As the injection material 8, mortar or cement milk may be used.
The above-described step of driving the receiving steel pipe 9 and the step of injecting the injection material 8 are performed for each of the plurality of guide members 3 of the guided arch support 10A.

<Placement process of secondary sprayed concrete 52>
Next, as shown in FIG. 8, the secondary shotcrete 52 is placed so as to overlap the primary shotcrete 51 between the rear adjacent arch support 10 </ b> B and the guided arch support 10 </ b> A. In particular, the secondary spray concrete 52 is placed in the receiving steel pipe guide recess 51b. As a result, the guide member 3 and the receiving steel pipe 9 on the rear side of the excavation with respect to the guide member 3 are buried in the secondary shotcrete 52.
In addition, you may make it the edge part of the excavation back side of the tip receiving steel pipe 9 protrude from the secondary spray concrete 52, and it may be embed | buried under the lining concrete 53 (FIG. 2).
The injection material 8 may be injected after the secondary spray concrete 52 is placed.
Thereafter, the tunnel 1 is excavated. By loosening the natural ground 2 on the front side of the excavation from the upper half of the face 1e with the receiving steel pipe 9, loosening of the natural ground 2 due to excavation can be suppressed.

As shown by a two-dot chain line in FIG. 1, after excavating 1 pitch P for ₁₀ minutes (for example, 1 meter), a front adjacent arch supporting work 10 </ b> C is installed. The angle θ ₉ of the receiving steel pipe 9 is set to about θ ₉ = 4 ° to 10 °, preferably about θ ₉ = 6 ° to 8 °, so that the front adjacent arch support 10C interferes with the receiving steel pipe 9. It can be installed without doing. In addition, it is possible to allow the leading steel pipe 9 to pass through the upper end of the front adjacent arch supporting work 10C. Further, it is possible to approach as much as possible the extension direction of the previously received steel pipe 9 in a direction parallel to the tunnel axis L _1, can minimize the excavation cross-section. Further, even if the receiving steel pipe 9 is made shorter than when the inclination angle θ ₉ is larger than the numerical value range, the receiving steel pipes 9 adjacent to each other in the front and rear direction (left and right in FIG. 1) can be overlapped. Therefore, the reinforcing effect of the natural ground 2 can be ensured, and stable tunnel excavation can be performed.
Thus, according to the embodiment of the present invention, it is possible to present a suitable inclination angle of the guide tube 30 and, therefore, the tip receiving steel pipe 9 in tunnel excavation by the AGF method.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the support part 20 of the guide member 3 is not limited to the plate shape with the through hole 21c, and may be a projection shape or the like as long as the guide cylinder 30 is supported by the guided arch support 10A.
Dimensions _{W 10, H 10} arches支保Engineering 10 described in embodiment, the pitch _{P 10,} spacing guided Arch shoring 10A, the value of such an outer diameter or height _{H 30} of the guide tube 30 are illustrative, The present invention is not limited to this.

  The present invention is applicable to tunnel excavation work.

L ₁ Tunnel axis θ ₃₀ Inclination angle 1 Tunnel 3 Guide member 9 Tip steel pipe 10A Guided arch support 20 Guide plate (support)
30 guide tube

Claims (2)

A guide member provided in a guided arch support that intersects with the proximal end of the steel pipe in the tunnel,
A guide tube that penetrates the guided arch support and through which the steel pipe is inserted;
A support portion for supporting the guide tube on the guided arch support,
A guide member for a tunnel, characterized in that the guide tube is inclined at an angle of 4 ° to 10 ° with respect to the tunnel axis toward the outer peripheral side of the tunnel toward the front side of tunnel excavation.   The guide member according to claim 1, wherein an inclination angle of the guide tube is 6 ° to 8 °.

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