JPH0468440B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a bypass tunnel construction method, and in particular, when it is desired to widen the required cross-sectional area of a predetermined part of an existing main tunnel, it is possible to construct a bypass tunnel without excavating a vertical shaft. This invention relates to a bypass tunnel construction method that can secure a cross-sectional area, reduce construction costs, and shorten the construction period.

[Prior Art] Generally, in underground tunnels in which power or communication cables are laid or water and sewage are distributed, it is necessary to make the necessary cross-sectional area of a predetermined part larger than that of the surrounding area, as necessary. For example, in underground tunnels in which power and communication cables are laid, cable joints inevitably occur, and in order to accommodate these joints, the cross-sectional area of the tunnel must be made larger than the surrounding area.

In this case, it is possible to carry out widening work from inside the tunnel, but since relatively high earth pressure is applied to the segments that support the tunnel inner wall, it is difficult to remove the segments from inside the tunnel.

Therefore, in the past, a vertical shaft was excavated from the ground to a predetermined point in the tunnel to perform widening work.

[Problems to be Solved by the Invention] However, conventional construction methods always require a vertical shaft, which not only increases the cost of excavating the shaft but also tends to lengthen the construction period. In particular, as tunnels tend to be dug deeper underground, the above problems tend to be exacerbated.

Additionally, prior to widening work, a large amount of chemicals had to be injected into a wide area of the ground to improve the ground to prevent crushing, which also exacerbated the above problems.

Furthermore, since the installation location of the shaft depends on ground conditions, it has become extremely difficult to secure land for the shaft in areas with a large number of houses.

[Object of the Invention] The present invention has focused on the above-mentioned problems and has been devised to effectively solve the problems.

The purpose of the present invention is to form a bypass tunnel without excavating a shaft when it is desired to increase the required cross-sectional area of a predetermined part of an existing main tunnel so that the sum of these cross-sectional areas becomes greater than or equal to the required cross-sectional area. The object of the present invention is to provide a bypass tunnel construction method that can reduce construction costs and shorten the construction period.

[Means and effects for solving the problem] The present invention provides a construction method in which a bypass tunnel is formed in a main tunnel composed of segments using a shield tunneling machine, in which a chemical is injected into the outer periphery of the main tunnel, which is the joining part of the bypass tunnel. After forming a ground improvement section by removing the segments of the joint section, openings are formed respectively, and a pod is installed in each opening from inside the main tunnel at a predetermined angle with respect to the axis of the main tunnel. At the same time as installing the pipe, filler is injected into the sheath pipe and solidified integrally with the ground improvement part, and then the shield excavation machine is guided by the sheath pipe while receiving a reaction force from the inner wall of the main tunnel and excavates into the ground. It is characterized in that it reaches the other opening.

According to this, in order to launch and reach the shield tunneling machine obliquely to the axis of the main tunnel,
It is possible to efficiently form a bypass tunnel close to the main tunnel, and in this case, filler is injected into the sheath pipe and solidified integrally with the ground improvement section, so it is possible to form a bypass tunnel on one side, which is impossible for shield tunneling machines. It becomes possible to dig smoothly without applying stress. In addition, since the inside of this tunnel will be used as the launch and arrival base for the shield excavation machine, it will be possible to proceed with the construction of the bypass tunnel in parallel with the construction of the main tunnel, shortening the construction period, and the shield excavation for the bypass tunnel will be possible. It will be possible to recover the aircraft inside this tunnel.

[Example] A preferred example of the method of the present invention will be described in detail below with reference to the accompanying drawings.

Figures 1 to 8 are process diagrams for explaining the method of the present invention, Figures 9 and 10 are diagrams showing a shield tunneling machine for carrying out the method of the present invention, and Figures 11 and 12 are FIGS. 13 and 14 are diagrams showing a main pushing device for implementing the method of the present invention, and FIGS. 13 and 14 are diagrams showing a middle pushing device for implementing the method of the present invention.

First, the apparatus used in the present invention will be explained. In the present invention, the inside of the main tunnel, which has already been excavated, is used as a starting base and the shield excavator excavates so as to penetrate the side wall of the main tunnel, so in order to accommodate this inside the tunnel, the shield shown in FIG. 9 is used. The diameter of the excavator 1 (approximately 1 meter) is smaller than the inner diameter (several meters) of the main tunnel. A conventionally known shield tunneling machine 1 is used, and a cutter face plate 3 is rotatably attached to the tip of a cylindrical shield frame 2, and a drive source 5 such as a motor is connected to the rotating shaft 4. There is. A cutter chamber 6 formed behind the cutter face plate 3 is connected to waste discharge pipes 7, 7 for discharging excavated soil.

Shield frame 2 is front shield frame 2
A and rear shield frame 2b, which are divided into two in the front and back, and these have a center bending mechanism consisting of a universal joint (not shown), and are configured to be freely bent by an appropriate angle, making it possible to excavate a curved tunnel. There is. In the illustrated example, the front shield frame 2a
is bent by an angle α. The bending angle of the front shield frame 2a is adjusted by adjusting the strokes of four hydraulic jacks 8 connected between the frame 2a and the rear shield frame 2b and arranged along the circumferential direction thereof.

Incidentally, the shield tunneling machine 1 excavates by using the main push device and the intermediate push device.

The main push device 9 shown in FIGS. 11 and 12 is fixed inside the main tunnel and is used to push the propulsion pipe and the shield excavator 1, which will be described later, into the main tunnel as shown in FIGS. 11 and 12. It is mainly composed of a main push base 10 to be fixed to a main push base 10 and a main push cart 12 having an L-shaped cross section that moves on a rail 11 laid by a predetermined length. A total of 4 fixed to the original push base 10
The main push hydraulic jack 13 is attached to the tip of each rod 14, and the push truck 12 is moved in the front and back direction by the protrusion and retraction of the rods 14. Incidentally, a propulsion tube 15 shown by a phantom line will be mounted on this truck 12.

The intermediate pushing device 16 shown in FIGS. 13 and 14 is installed immediately after the shield tunneling machine 1, and is in direct contact with the shield tunneling machine 1 to propel it. A disk-shaped push stand 20 is attached to the tip of each rod 19 of a total of four fixed intermediate push hydraulic cylinders 18...
By moving this push platform 20 back and forth, the rear end of the shield excavator 1 is pushed.

The method of the present invention will be specifically explained using the above-mentioned apparatus with reference to FIGS. 1 to 8.

FIG. 1 shows the main tunnel that has already been shield-excavated, and FIG. 2 shows a cross-sectional view taken along the line shown in FIG. 1. For example, communication cables, power cables, etc. will be installed within this main tunnel 21, and the joints of these cables will be located at predetermined locations P within the tunnel.
(In the illustrated example, the longitudinal center of the tunnel)
The required cross-sectional area is larger than that of the surrounding area. This part, that is, the predetermined point P, was determined in advance at the design stage of the main tunnel, so
Bypass tunnels 22 and 23 connect the upstream side and the downstream side around this part.
In the illustrated example, the left side is the upstream side and the right side is the downstream side. In addition, in the illustrated example, two bypass tunnels 22 and 23 are formed, but the number is not limited, and the cross-sectional area of each bypass tunnel and the cross-sectional area of the main tunnel are Set the number so that the total sum is greater than or equal to the required cross-sectional area. Therefore, as the cross-sectional area of one bypass tunnel increases, the number of bypass tunnels decreases accordingly.

The partition wall that separates the starting base 24 and arrival base 25 of the shield tunneling machine, which are the connecting parts of the bypass tunnels 22 and 23, is made of steel segments 26 and 27 in advance to facilitate this removal, and the other parts are It is made up of inexpensive concrete segments 28. Note that the starting base 24 and the destination base 25 may be reversed on the upstream and downstream sides of the main tunnel.

First, a chemical is injected into the entire outer periphery of the steel segments 26 and 27, which is to become the joining part of the bypass tunnel 22, to form ground improvement parts 29 and 30 as shown in FIG. 2 to prevent collapse during excavation. do. In particular, the ground improvement section 30 on the arrival base side
The wall is made thicker to accommodate excavation errors.

Next, the steel segment 26 on the starting base 24 side
The part that will become the opening of the bypass tunnel is cut and removed to expose the ground improvement part 29 inside the tunnel, and as shown in FIG.
With its open end 31a facing the main tunnel 21 side, the steel sheath pipe 31, which guides the shield tunneling machine during the initial stage of excavation, is connected to a steel segment at a predetermined angle with respect to the longitudinal direction (axis) of the main tunnel. 26 is welded to the circumferential end of the opening.
Note that a blind plate 32 is attached to the open end 31a to close it off. The inner diameter of the sheath pipe 31 is slightly larger than its outer diameter because it is necessary to accommodate the bypass tunnel shield excavator 1. In this case, the angle of the sheath pipe 31 with respect to the main tunnel is determined so that the shield excavator can be installed near the open end 31a of the sheath pipe 31. Next, as shown in FIG. 4, the shield tunneling machine 1 and the main pushing device 9 are set in this order so as to face the blind plate 32 attached to the open end 31a of the sheath pipe 31. In this case, the shield excavator 1 is placed on the main push cart 12, and a pair of support pieces 33 attached to the top of the cart in the width direction prevent the excavator 1 from rolling (see FIG. 11). and,
A reaction wall 34 is strongly constructed of concrete or the like in contact with the base end of the main pushing device 9 to receive the reaction force during propulsion of the shield excavator.

Next, the blind plate 32 that closes the open end 31a of the sheath pipe 31 is removed, and the main push hydraulic jack 13 is extended by an appropriate stroke as shown in FIG. and close the open end 31a again. Then, a filler material 35 made of resin or poorly distributed concrete is injected into the clearance part formed between the sheath pipe 31 and the shield excavator 1, and this part is hardened to a predetermined hardness. As will be described later, by excavating through this, it becomes possible to smoothly excavate toward the ground side without applying unreasonable one-sided stress to the shield excavator. Therefore, it is desirable that the strength of the filler 35 be approximately the same as the strength of the ground G or the ground improvement portion 29.

Next, the shield excavator 1 is driven while extending the main push hydraulic jack 13 to start excavation, and at the same time, the main push hydraulic cylinder 13 is extended to dig into the filler material 35. Main push hydraulic jack 13
When the excavation has been completed for the entire stroke, as shown in Fig. 6, the main push hydraulic jack 13 is retracted and reset. Next, the intermediate push device 16 is placed on this main push cart 12, and the main push hydraulic pressure is turned on again. Jyatsuki 13
Extend and start digging. Then, if the main push hydraulic jack 13 extends its full stroke,
This is reset again, and this time the annular propulsion tube 15 is set on the main push cart 12. Subsequent excavation is carried out by repeatedly extending the full stroke of the hydraulic jack 13 and resetting it, and successively connecting the propulsion pipes 15 as shown in FIG. The shield excavator 1 and the intermediate pushing device 16 advance continuously, and this pushing platform 20 is extended by appropriately extending the intermediate pushing hydraulic jack 18.
The excavator 1 in contact with the excavator 1 is moved forward to carry out preliminary excavation, and the main push device 9 performs the main push, thereby sequentially press-fitting the connected propulsion pipes 15 in their entirety. As a result, the excavator 1 moves to the ground improvement section 29.
It penetrates and digs into the ground G.

The excavation direction is set using the hydraulic jack 8 of the excavator 1.
By providing a stroke difference between the two, the bending angle of the front shield frame 2a is changed to allow digging in a desired direction (see FIG. 9). In addition, the direction of excavation can be corrected using the intermediate push hydraulic jack 1 of the intermediate push device 16.
This is done by providing a stroke difference between 8..., and the combination of these makes sure that the robot moves in the desired direction.

On the other hand, while a series of excavation operations are being carried out in this manner, the reaching sheath pipe 36 is installed at the reaching base 25 in the same manner as that installed at the starting base 24 (see FIG. 8). It is filled with filler material and is waiting for the excavator to arrive. Then, the excavator 1 that has excavated the required distance gradually changes its excavation direction and excavates into the reaching sheath pipe 36, and finally, the excavator 1 excavates from the open end 31a.
Excavation of the bypass tunnel 22 is completed by exposing the tip of the bypass tunnel 22.

If the bypass tunnel 22 needs to be restored, a plurality of tunnels are excavated by repeating the same operations as described above. FIG. 15 shows that a plurality of bypass tunnels 2 are constructed along the main tunnel 21 by the method described above.
FIG. 2 is a perspective view showing a state in which 2... are formed. In this way, the main tunnel 21 and the bypass tunnel 2
At a predetermined location P within the main tunnel 21, or
Cables and the like will be jointed within the bypass tunnels 22 and 23 which are arranged in parallel to this.

On the other hand, the shield excavator 1 and the intermediate pusher 16 recovered into the main tunnel will be disassembled and used again.

In the above embodiment, the sheath pipes were welded and connected to the starting base 24 and the destination base 25 of the excavator 1, but the sheath pipes only need to be installed at least at the starting base, so that the digging The aircraft can be easily launched underground from within this tunnel.

Furthermore, although the above embodiment is a so-called push pipe construction method in which the entire tunnel is pushed in using a pusher, if the tunnel system is large, a bypass tunnel construction method using a conventional shield machine that advances the tunnel while assembling segments is also possible.

[Effects of the Invention] In summary, according to the present invention, since the shield tunneling machine starts and reaches obliquely with respect to the axis of the main tunnel, it is possible to efficiently form a bypass tunnel close to the main tunnel. Since the filling material is injected into the sheath pipe and solidified integrally with the ground improvement section, the shield excavator can dig smoothly without being subjected to unreasonable unilateral stress. In addition, in order to use this tunnel as a launch and arrival base for shield tunneling machines,
The construction of the bypass tunnel can proceed in parallel with the construction of the main tunnel, shortening the construction period, and the shield excavator for the bypass tunnel can be recovered inside the main tunnel.

[Brief explanation of the drawing]

1 to 8 are process diagrams showing the method of the present invention, and FIG. 1 is a longitudinal sectional view showing the main tunnel, and FIG.
The figure is a cross-sectional view taken along the line arrow in Figure 1, Figure 3 is a plan view showing the state in which the pod pipe is attached to the ground improvement section, and Figure 4 is a plan view showing the state in which the shield tunneling machine is set on the pod pipe. , Fig. 5 is a plan view showing the state in which filler is loaded into the pod pipe, Fig. 6 is a plan view showing the state in which the intermediate pushing device is installed between the shield excavator and the main pushing device, and Fig. 7 is the bypass tunnel. A plan view showing the shield tunneling machine during excavation, Figure 8 is a plan view showing the state in which the shield tunneling machine has reached the base, Figure 9 is a vertical cross-sectional view showing the shield tunneling machine, and Figure 10 is a partial cross-section of the same. A plan view, FIG. 11 is a side view showing the main pushing device, FIG. 12 is a partial sectional plan view of the same,
FIG. 13 is a side sectional view showing the intermediate pushing device, FIG. 14 is a partial sectional plan view thereof, and FIG. 15 is a perspective view showing a main tunnel in which a large number of bypass tunnels are formed. In addition, 1 is a shield excavator, 9 is a main push device, 1
6 is the middle push device, 21 is the main tunnel, 22, 23
is a bypass tunnel, 24 is a starting base, 25 is a destination base, 31 is a sheath pipe, and P is a predetermined location.

Claims (1)

[Claims] In the method of forming a bypass tunnel using a shield tunneling machine in a main tunnel composed of 1 segments, a chemical is injected into the outer periphery of the main tunnel where the bypass tunnel joins to form a ground improvement section, and then the above-mentioned joint section is The segments are removed to form openings, and sheath pipes are attached to these openings from inside the main tunnel at a predetermined angle with respect to the axis of the main tunnel, and a filler is injected into the sheath pipe. A bypass characterized in that the shield tunneling machine is solidified integrally with the ground improvement part, and then the shield tunneling machine receives a reaction force from the inner wall of the main tunnel and is guided by a sheath pipe to tunnel underground until it reaches the other opening. tunnel construction method.