JPS6131594A - Bypass tunnel construction method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 the necessary cross-sectional area, reduce construction costs, and shorten the construction period.

[Prior Art J] In general, in underground tunnels in which power or communication cables are laid or water and sewage are distributed, it is necessary to make the required 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, and work such as widening the tunnel was carried out.

[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.

[Summary of the invention] The present invention is based on the knowledge that in order to secure the necessary cross-sectional area of the main tunnel, it is sufficient to connect the upstream and downstream sides of a predetermined part of the main tunnel with a bypass tunnel having a predetermined cross-sectional area. The configuration of the present invention that meets the above objective is to bypass a predetermined location in the main tunnel where it is necessary to increase the cross-sectional area, and to create a bridge between the upstream side and the downstream side of the predetermined location. is excavated by a shield excavator whose diameter is smaller than the inner diameter of the main tunnel to form a bypass tunnel with a predetermined cross-sectional area, and the sum of the cross-sectional area of this bypass tunnel and the cross-sectional area of the main tunnel is the required cross-sectional area. The gist is that the area is greater than or equal to the area.

[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, since the inside of the main tunnel, which has already been excavated, is used as a starting base, the shield excavator excavates so as to penetrate the side wall of the main tunnel, so in order to be able to accommodate this inside the tunnel, the ninth
The diameter of the shield tunneling machine 1 shown in the figure (approximately 1 meter) is smaller than the inner diameter (several meters) of the main tunnel. A conventionally known shield tunneling machine 1 is used as the shield tunneling machine 1. A shield 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 at the rear of the cutter face plate 3 is connected to waste discharge pipes 7, 7 for discharging excavated soil.

The shield frame 2 is divided into a front shield frame 2a and a rear shield frame 2b, which have a center bending mechanism consisting of a universal joint (not shown), and are configured to be bent at an appropriate angle, and have a curved shape. It makes it possible to excavate tunnels. In the illustrated example, the front shield frame 2a is shown bent by an angle α. The bending angle of the front shield frame 2a can be adjusted using this frame 2.
This is done by adjusting the strokes of four hydraulic jacks 8 connected between the rear cutter frame 2b and the rear cutter 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 pushing device 9 shown in FIGS. 11 and 12K is fixed inside the main tunnel and pushes forward the propulsion pipe and the shield excavator 1, which will be described later. The original push base 10 to be fixed
It is mainly composed of a main push cart 12 with an orthogonal cross-section that moves on a rail 11 laid a predetermined length,
There are a total of 4 main push carts 12 fixed to the main push base 1o.
Each rod 14 of the base hydraulic jack 13...
The main push cart 12 is moved in the front and back direction by the rods 14, which are attached to the tips of the rods 14 and retract. Incidentally, a propulsion tube 15 shown by a phantom line will be mounted on this truck 12.

The intermediate push device 16 shown in FIGS. 13 and 14 is installed immediately after the shield excavator 1, and is in direct contact with the shield excavator 1 to propel it, and includes a cylindrical intermediate push base 17 and a It is mainly composed of a disk-shaped push stand 2o attached to the tip of each rod 19 of a total of four fixed intermediate push hydraulic cylinders 18..., and this push stand 2o can be moved back and forth. This pushes the rear end of the shield tunneling machine 1.

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

Figure 1 shows the main tunnel that has already been shield-excavated, and Figure 2 shows a sectional view taken along the line ■--■ in Figure 1. For example, communication cables, power cables, etc. will be laid inside this main tunnel 21, and these cables will be laid at a predetermined point P in the tunnel where their joints are located (in the illustrated example, the central part in the longitudinal direction of the tunnel). The required cross-sectional area becomes larger compared to the surrounding area. Since this part, that is, the predetermined point P, is determined in advance at the design stage of the main tunnel, the bypass tunnel 22 is connected to the upstream and downstream sides around this part.
．． It will be connected at 23. In the illustrated example, the left side is the upstream side and the right side is the downstream side. Further, 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, if the cross-sectional area of one bypass tunnel increases,
The number of bypass tunnels will be reduced accordingly.

In order to facilitate this removal, the partition wall that separates the starting base 24 and arrival base 25 of the shield excavator, which are the joining parts of the bypass tunnels 22 and 2, is made of steel segments 26 and 27 in advance, and the other parts are is made up of inexpensive concrete segments 28. Note that the starting base 24 and the destination base 25 may be reversed upstream and downstream of the main tunnel.

First, the portion that is to become the joining part of the bypass tunnel 22, that is, the steel segment 26. ．． A chemical is injected into the entire outer circumference of the ground improvement section 29.3 in advance as shown in Fig. 2.
0 to prevent collapse during excavation. In particular, the ground improvement portion 3° on the reaching base side is made thicker to accommodate excavation errors.

Next, the part of the steel segment 26 on the side of the starting base 24 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 the open end 31a facing the main tunnel 21 side, the steel sheath pipe 31 that guides the shield tunneling machine during the initial stage of excavation is held at a predetermined angle with respect to the longitudinal direction of the main tunnel, and the steel segment 26 is
Weld connection to the circumferential edge 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 digging ta1 and the 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 tube 31. In this case, the shield excavator 1 is
2, and a pair of support pieces 33 attached in the upper width direction of this truck prevent the excavator 1 from rolling (see FIG. 11). Then, 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 when the shield tunneling machine is propelled.

Next, the blind plate 32 that closes the open end 31a of the sheath pipe 31 is removed, and the main push hydraulic jack 1 is removed as shown in FIG.
3 by an appropriate stroke, the tip of the shield tunneling machine 1 is inserted into the sheath tube 31, and the open end 31a is closed 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 digging this, it becomes possible to smoothly dig toward the ground side without applying unreasonable unilateral 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 filling material 35. After digging the entire stroke of the main push hydraulic jack 13, the main push hydraulic jack 13 is retracted and reset as shown in FIG. 6, and then the intermediate push device 16 is placed on this main push cart 12. Then press the hydraulic jack 1 again.
Extend 3 and start digging. Then, when the main push hydraulic jack 13 has extended its full stroke, it is reset again and the annular propulsion pipe 1 is placed on the main push truck 12.
Set 5. Then, subsequent excavation is carried out by repeatedly extending the full stroke of the main push hydraulic jack 13 and resetting it, as shown in FIG. !1 and the intermediate push device 16 advance continuously, and by appropriately extending the intermediate push hydraulic jack 18, the excavator 1 in contact with the push platform 20 is advanced to perform advance excavation.
The entire connected propulsion tubes 15 are sequentially enlarged by pushing with the pushing device 9. As a result, the excavation Ia1 penetrates the ground improvement portion 29 and digs into the ground G.

The digging direction is set by providing a stroke difference in the hydraulic jack 8 of the excavation machine 1 to change the bending angle of the front shield frame 2a and digging in the desired direction (see Fig. 9). This is done by providing a stroke difference between the intermediate push hydraulic jacks 18 of the intermediate push device 16, and the combination of these makes it possible to reliably advance in the desired direction of propulsion.

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). Load the filler into this and have the excavator reach it. Then, excavation I11 was carried out by excavating the required distance.
The excavator 1 excavates into the reaching sheath pipe 36 while gradually changing its excavation direction, and finally excavates the excavator 1 from its open end 31a.
The tip of the bypass tunnel 22 is sprayed out to complete the excavation of the bypass tunnel 22.

If a plurality of bypass tunnels 22 are required, the same operations as described above are sequentially repeated to excavate the plurality of tunnels. 1st
FIG. 5 is a perspective view showing a state in which a plurality of bypass tunnels 22 are formed along the main tunnel 21 by the method described above. In this way, the sum of the cross-sectional areas of the main tunnel 21 and the bypass tunnel 22 is larger than the required cross-sectional area, and a predetermined point P in the main tunnel 21 or in the bypass tunnel 22 or 23 installed in parallel thereto is secured. You will need to joint the cables etc.

On the other hand, the shield excavation m' recovered in the main tunnel again
+ and the middle push device 16 will be disassembled and used again.

In the above embodiment, the starting base 24 of the excavation ta1
Although sheath pipes are welded to and connected to the reach base 25, the present invention is not limited to this, and for example, a Huyume pipe or the like may be attached using the push pipe construction method.

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 short, the method of the present invention has the following advantages when securing the necessary cross-sectional area at a predetermined location within the main tunnel that has already been formed.
By connecting the upstream side and the downstream side and forming a bypass tunnel using a shield tunneling machine, the sum of the cross-sectional area of this tunnel and the cross-sectional area of the main tunnel is greater than the required cross-sectional area, so it is possible to This technology not only eliminates the need for vertical shafts, shortens the construction period and reduces construction costs, but also increases the degree of freedom in design because the bypass tunnel excavation location is not affected by ground conditions. It is possible to exhibit the following effects.

[Brief explanation of the drawing]

Figures 1 to 8 are process diagrams showing the method of the present invention, Figure 1 is a longitudinal cross-sectional view showing the main tunnel, and Figure 2 is a
3 is a plan view showing the condition where the pod pipe is attached to the ground improvement section, 4 is a plan view showing the state where the shield excavator is set on the pod tube, and 5 is the sectional view taken along the -■ line. A plan view showing the state in which filler is loaded into the sheath pipe, Fig. 6 is a plan view showing the state in which the intermediate push device is installed between the shield excavator and the main push device, and Fig. 7 shows the shield excavation during bypass tunnel excavation. 8 is a plan view showing the state in which the shield tunneling machine has reached the destination base; FIG. 9 is a vertical sectional view showing the shield tunneling machine; FIG. 10 is a partial sectional plan view of the same;
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 of the same, and Fig. 15 is a partial sectional plan view of the main pushing device. FIG. 2 is a perspective view showing a main tunnel in which a bypass tunnel is formed. In addition, 1 is the shield excavator, 9 is the main push device, 1 and 6 are the middle push devices, 21 is the main tunnel, 22.23 is the bypass tunnel, 24゛ is the starting base, 25 is the destination base, 31 is the sheath pipe, P is a predetermined location. Patent applicant Tokyo Electric Power Company Ishikawajima-Harima Heavy Industries Co., Ltd. Agent Nobuo Kinutani Figure 1 Figure 7 Figure 8 Figure 1 ON Figure 11 Figure 12 Figure 13 Figure 14 Figure 15

Claims (1)

[Claims] When securing the necessary cross-sectional area to accommodate the joints, etc. of the cables at predetermined locations within the main tunnel where power cables, etc. are laid, the above-mentioned A bypass tunnel is formed by excavating between the upstream side and the downstream side of a predetermined location using a shield excavator whose diameter is smaller than the inner diameter of the main tunnel, and the cross-sectional area of the main tunnel and the bypass tunnel are A bypass tunnel construction method characterized in that the total sum with the cross-sectional area of is equal to or larger than the above-mentioned required cross-sectional area.