JPS6346237B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention provides a method for excavating an enlarged tunnel approximately concentric with the normal diameter tunnel around the axial end face of a primary segment forming the normal diameter tunnel. The present invention relates to a circumferential shield excavator, and particularly relates to a circumferential shield excavator that has good excavation workability and has a retaining effect.

(Prior art) In general, the shield method is often used as an excellent construction method for tunnel excavation for subway construction and underground cable burying work, but it is also used for construction of subway stations and underground cable connection works. In order to install a tunnel, it becomes necessary to enlarge a part of the tunnel.

Conventional methods for carrying out this expansion work include, for example, digging a vertical shaft in each area planned for expansion;
When the area to be expanded is reached, an expanding cutting section is added to the cutter head of the shield machine to carry out expanded excavation.

However, in recent years, the method of digging vertical shafts has become increasingly difficult to implement in view of the fact that tunnel construction routes have become deeper underground due to the restrictions of various aboveground and underground obstacles in urban areas. There was also a cost problem, as the shaft that had been painstakingly excavated had to be backfilled, except for a portion, after the expansion work.

In addition, with the method of adding an enlarged blade part to the cutter head, if the enlarged excavation diameter becomes large, it will not be able to resist the earth pressure from the surrounding surface, so the excavation diameter will be limited. The excavation operations cannot be carried out in parallel, and the enlarged blade section must be attached and detached each time, resulting in problems such as reduced efficiency.

Therefore, in several previous applications, the applicant has proposed tunnel excavation methods that improve these conventional methods.

According to the construction method proposed earlier, an enlarged excavation section is provided at the starting end of the planned expansion area in the tunnel where the primary segment (shield) is installed, and this is the starting point for the expanding shield machine, and the tunnel is then installed along the outer periphery of the primary segment. An expanding shield machine that is propelled in the longitudinal direction is arranged, and the expanding shield machine is propelled to perform expanded excavation, and at the same time, the primary segments of the area scheduled for expanded excavation are sequentially removed and secondary segments are applied to the expanded excavated area. .

In this case, various methods can be considered to provide an expanded excavation section that will serve as a starting base for the expanded shield machine, so similarly, in the applicant's previous application,
We have proposed an expanded shield excavation method (circumferential shield excavation method), which is an expanded excavation method for launching bases.

An overview of the previously proposed circumferential shield excavation method will be explained based on FIGS. 1 to 5.

FIG. 1 shows an axial end face 1a of a primary segment ₁ forming a small diameter (normal diameter) tunnel T1. Note that when starting the excavation of an enlarged tunnel from the end of the primary segment 1, the end face 1a of the primary segment 1 is exposed in advance. However, when excavating an enlarged part in the middle of the existing primary segment 1, , the lower part of the primary segment 1 already attached to the tunnel T ₁ is removed as much as necessary to expose the end face 1b. Also when performing enlarged excavation at the end of the primary segment 1, the end face 1b
Since the method is almost the same when performing enlarged excavation, the case where enlarged excavation is performed from the end face 1b will be described.

As shown in FIG. 1, first, a rectangular cylindrical steel box 2 corresponding to the removed area on the lower side of the primary segment 1 is placed inside the segment 1. Then, a reaction force is obtained from the upper inner surface of the primary segment 1 by a jack (not shown), and the steel box 2 is press-fitted into the ground 3 below the primary segment 1. As shown in FIG. 2, when the steel box 2 has entered the ground 3 to a desired depth, the earth and sand inside the steel box 2 is removed by hand digging or other excavation means. In addition, when it is necessary to dig deeper, the same steel box 2 is stacked on top of the previously sunk steel box 2, pushed down into the ground 3 by the jack, and the same operation as described above is repeated.

By the way, the above-mentioned steel box 2 is for retaining the mountain, and is installed to prevent the collapse of the ground 3 in the excavated area, but depending on the soil quality, this can be omitted, and the hole is simply dug. Just that is enough.

Next, as shown in FIG. 2, a circumferential shield excavator 4 is installed in the hole surrounded by the steel box 2, and is propelled approximately in the circumferential direction of the primary segment 1 to manually dig with a pick or the like. At the same time, the secondary segments 5 are sequentially installed behind the excavation.

Here, the circumferential shield machine 4 consists of a circumferential shield machine main body 6 having a substantially U-shaped cross section, and a jack 7 for propelling the circumferential shield machine main body 6. Further, the secondary segment 5 installed in the enlarged part at the rear of the circumferential shielding machine main body 6 has almost the same dimensions and shape as the circumferential shielding machine main body 6, and its cross section is almost the same as that of the circumferential shielding machine main body 6. It is U-shaped.

Various methods can be considered for attaching the secondary segment 5, but for example, a sliding shoe 8 is attached to each free end of the secondary segment 5, and a rail-shaped guide ring is used to receive and slide the sliding shoe 8. 9 is fixed to each of the removed end faces 1b of the primary segment 1 so that the secondary segment 5 can move along the guide ring 9 in the circumferential direction of the primary segment 1. The secondary segments 5 are attached to the guide ring 9 at the position of the steel box 2, and as the circumferential shield excavator 4 advances, the number of secondary segments 5 attached to the guide ring 9 is increased. , the entire secondary segment 5 is sequentially pushed toward the circumferential shield excavator 4 side. Note that it is convenient to make the guide ring 9 replenishable.

Further, it is preferable that the circumferential shield machine main body 6 of the circumferential shield excavator 4 is also attached to the guide ring 9 in exactly the same manner as the secondary segment 5, and the circumferential shield machine body 6 of the circumferential shield machine 4 is also attached to the guide ring 9 in exactly the same manner as the secondary segment 5. It is better to propel it in the direction. The circumferential shielding machine main body 6 is similar to a general shielding machine, and has a skin plate 6a with a cutting edge formed on the outer periphery of the tip. In addition, one end of the jack 7 is attached inside the circumferential shield machine body 6, and the other end initially receives reaction force from the steel box 2 or earth 3, and then receives reaction force from the secondary segment 5. The power is obtained to propel the circumferential shield machine body 6.

When the excavation by the circumferential shield excavator 4 is completed and the installation of the secondary segment 5 is completed, the fourth
As shown in Figures 5 to 5, an enlarged tunnel _T2 is formed in the middle of the small diameter tunnel _T1 . Expanding tunnel T ₂
may be used as is, but it will be used as a starting base for an expanding shield machine (not shown) that excavates in the longitudinal direction of the small diameter tunnel _T1 , and as shown by the imaginary line, it will be used as a starting base for an expanding shield machine (not shown) that excavates in the longitudinal direction of the small diameter tunnel _T1 . In some cases, the enlarged tunnel may be extended further. Such an expanding shield machine for excavating an expanding tunnel in the longitudinal direction of the small diameter tunnel _T1 has been described in detail in several of the applicant's previous applications as described above.

As mentioned above, according to the enlarged shield excavation method using the circumferential shield excavator 4, an enlarged tunnel can be created in a part of a small diameter (normal diameter) tunnel without providing a vertical shaft or adding an enlarged blade part to the shield machine. T ₂ can be efficiently formed. In addition, using the expanded tunnel T ₂ formed by this circumferential shield excavator 4 as a starting base, a small diameter tunnel will be constructed.
The enlarged tunnel T ₂ can be extended in the longitudinal direction of T ₁ , making it extremely easy to locally enlarge the tunnel.

(Object of the Invention) An object of the present invention is to provide a circumferential shield excavator that can enhance the circumferential excavation ability and earth and sand discharge ability of the primary segment, and can perform safe work by being secured to the mountain. There is a particular thing.

(Summary of the Invention) The gist of the present invention is that a waterjet type excavator is attached to a circumferential shield machine body which is propelled in the circumferential direction by a jack, and the waterjet type excavator A mountain retaining plate provided on the front side in the direction of movement of the machine body, a rotatable nozzle protruding in front of the mountain retaining plate for excavating the ground with a jet jet, and a rotatable nozzle that extends in the direction of propulsion of the circumferential shield machine. This is a circumferential shield excavator comprising a power source that rotates in a substantially vertical plane, and an earth and sand discharge means that sucks and discharges earth and sand that has been excavated and fluidized by the jet jet to the rear of the pile retaining plate.

(Example) Hereinafter, an explanation will be given based on an example shown in FIGS. 6 and 7. Note that the same parts as those described in FIGS. 1 to 5 will be described using the same reference numerals.

In the illustrated embodiment, the circumferential shield machine 4a according to the present invention includes a circumferential shield machine main body 6 having a substantially U-shaped cross section, and a circumferential shield machine main body 6 that propels the circumferential shield machine main body 6, similar to the previously proposed ones. One (for example, three) jacks 7 are provided.
Furthermore, a waterjet type excavator 1 excavates the ground in front of the circumferential shield machine main body 6 of the present invention, which is partitioned by a retaining plate 12a provided on the front side in the direction of movement.
0.

The water jet type excavator 10 has a rotatable nozzle 11 that generates a jet jet of fluid for excavating the ground, and a rotatable nozzle 11 that is arranged in a plane substantially perpendicular to the excavation direction of the circumferential shield machine body 6. a power source such as an air motor (not shown), and a soil discharge means 12 that sucks and discharges the soil excavated and fluidized by the jet jet to the rear of the pile retaining plate 12a. There is.

Each of the nozzles 11 has three spout ports 11a.
Each jet port 11a rotates in the jet direction of the jet jet J.

The earth and sand discharge means 12 includes a mountain retaining plate 12a,
It is equipped with a suction pipe 12b for suctioning excavated earth and sand accumulated on the front surface of the mountain retaining plate 12a, and a vacuum pump (not shown) connected to the suction pipe 12b.

Circumferential shield excavator 4 configured as above
When excavating using a, the circumferential shield machine main body 6 is propelled in the same way as the previously proposed one,
1 rotates while emitting a jet of fluid to excavate the ground in front that is partitioned by the mountain retaining plate 12a. The excavated and fluidized earth and sand is sequentially discharged to the rear of the mountain retaining plate 12a by the earth and sand discharge means 12. Therefore, the excavation efficiency in the circumferential direction is improved.

(Effects of the Invention) In the circumferential shield excavator of the present invention, the ground around the propulsion blade mouth is evenly excavated by the jet injection nozzle that rotates in front of the mountain retaining plate provided on the front side in the direction of travel. At the same time, the fluidized earth and sand are sequentially discharged to the rear of the retaining plate, allowing for efficient work with continuous excavation. In addition, since the face is partitioned with retaining plates and is not opened, it is safe, especially when working with a circumferential shield excavator propelled upward.

[Brief explanation of drawings]

Figures 1 and 2 are schematic cross-sectional views showing the process of the circumferential shield excavation method that has already been proposed, Figure 3 is an enlarged cross-sectional view taken along the - line in Figure 2, and Figure 4
The figure is a schematic end view of an enlarged tunnel completed by the construction method shown in Figures 1 and 2, Figure 5 is a sectional view taken along the - line in Figure 4, and Figure 6 is a diagram showing the first construction of the present invention.
FIG. 7 is a vertical cross-sectional view of the circumferential shield tunneling machine according to the embodiment, and is a cross-sectional view taken in the direction of the arrow in FIG. 6. T ₁ ...Small diameter (normal diameter) tunnel, _T2 ...Expanded tunnel, 1...Primary segment, 1a, 1b...
...End face, 2...Steel box, 3...Ground, 4a
...Circumferential shield excavator, 5...Secondary segment, 6...Circumferential shield machine main body, 6a...Skin plate, 7...Jatsuki, 8...Sliding shoe,
9... Guide ring, 10... Water jet excavator, 11... Nozzle, 11a... Spout, 12... Sediment discharge means, 12a... Mountain retaining plate, 12b... Suction pipe.

Claims (1)

[Claims] 1 A circumferential shield excavator for excavating an enlarged tunnel approximately concentric with the normal diameter tunnel around the axial end face of the primary segment forming the normal diameter tunnel, the machine In a circumferential shield excavator comprising a circumferential shield machine main body that is propelled in a substantially circumferential direction along the circumferential shield machine body, and a jack that propels the circumferential shield machine main body, the circumferential shield machine main body is provided on the front side in the traveling direction of the circumferential shield machine main body. a rotatable nozzle protruding in front of the mountain retaining plate for excavating the ground with a jet stream; and power for rotating the nozzle in a plane substantially perpendicular to the direction of propulsion of the circumferential shield machine. A circumferential shield excavator equipped with a waterjet type excavator comprising a water jet source and an earth and sand discharge means that sucks and discharges earth and sand that has been excavated and fluidized by the jet jet to the rear of a mountain retaining plate.