JPS6217077B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circumferential shield excavator for excavating an enlarged tunnel approximately concentric with the small diameter tunnel around the axial end face of a primary segment forming the small diameter tunnel, In particular, the present invention relates to a circumferential shield machine that has good excavation workability and has a heap retaining effect.

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 often used when constructing subway stations or establishing underground cable connection workshops. In this case, it becomes necessary to enlarge a part of the tunnel.

The conventional method for carrying out this expansion work is to dig a vertical shaft from the ground in the area where the tunnel is planned to be expanded, which was generally constructed using the shield method.
This shaft was used to construct an expanded tunnel.

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.

Therefore, in several previous applications including Japanese Patent Application No. 56-153966 (Japanese Unexamined Patent Publication No. 58-98595), the applicant has proposed a tunnel expansion excavation method that improves 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 installed, 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 installed 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 earth and is installed to prevent the collapse of the ground 3 in the excavated area, but depending on the soil quality, this may be omitted, and the box 2 may simply be placed in the hole. All you have to do is dig in.

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.

An object of the present invention is to provide a circumferential shield excavator that can further improve the excavation ability of the primary segment in the circumferential direction and also have a mountain retaining effect, in order to further improve the workability of excavating an expanded tunnel. It's about doing.

The gist of the present invention is that a power excavator that also serves as a heap is built into the front side in the advancing direction of a circumferential shield machine that performs enlarged excavation along the circumferential direction.

The present invention will be explained below based on the embodiments shown in FIGS. 6 to 11. Note that the same parts as those described in FIGS. 1 to 5 will be described using the same reference numerals.

In the first embodiment shown in FIGS. 6 and 7, a circumferential shield excavator 4a according to the present invention has a circumferential shield machine main body 6 having a substantially U-shaped cross section, similar to the previously proposed one.
and at least one (for example, two) jacks 7 for propelling the circumferential shield machine main body 6, and further, according to the present invention, a powered excavator built in the front side of the circumferential shield machine main body 6 in the traveling direction. It is equipped with 10 machines.

In this embodiment, the power excavator 10 has at least one screw auger 11 (for example, four screw augers 11), which excavates a face when the circumferential shield machine main body 6 advances, and distributes the excavated earth and sand to the circumference. It is sent to the rear of the shield machine main body 6. Further, a guide member 12 for earth and sand is provided around the screw auger 11, and these screw auger 11 and guide member 12 for earth and sand close the front opening of the circumferential shielding machine main body 6. The power excavator 10 also has a heap retaining effect, making work safer and making it possible to deal with a wide range of soil types.

8 and 9 show a second embodiment of the present invention, in which the power excavator 10 includes an earth and sand discharge means 13 for carrying out earth and sand excavated by each screw auger 11, and this earth and sand discharge means Reference numeral 13 includes a plurality of nozzles 14 for jetting a fluid to fluidize the earth and sand excavated by each screw auger 11, and a plurality of nozzles 14 for sucking the fluidized earth and sand together and discharging the fluidized earth and sand from outside the circumferential shield machine body 6. It has a vacuum pump 15 for discharging water.

In this embodiment, excavated earth and sand are automatically discharged, making the excavation work more efficient.

10-11 show a third embodiment of the present invention,
At least one powered excavator 10 (e.g. 8
It consists of a cylindrical rotary cutter (drum cutter) 16 which is pivotally supported in the horizontal direction, and at least one (for example, two
It consists of a screw conveyor 17 for books.
In this embodiment, even if the excavated earth and sand has no fluidity, it can be easily carried out. Note that the reference numeral 16a indicates a cutter bit.

As is clear from the description of each embodiment, in the present invention, a powered excavator is built into the front side in the advancing direction of a circumferential shield machine that performs enlarged excavation along the circumferential direction, so continuous excavation is possible and efficiency is improved. It also has the advantage of ensuring safety because the face is not open. In addition, mechanical excavation makes it possible to accumulate and continuously carry out earth and sand. Furthermore, it is safer because there is no need for people to enter the circumferential shield machine that performs enlarged excavation along the circumferential direction during excavation. Furthermore, as mentioned above, the power excavator also serves as a heap, so it can be used on a wide range of soil types. Therefore, there is no need to repeat excavation and damming, and the excavation work time can be shortened. Another advantage is that it improves workability during upward excavation.

[Brief explanation of the drawing]

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 cross-sectional view taken along the - line of Figure 4, and Figure 6 is a diagram showing the first construction of the present invention.
A longitudinal sectional view of a circumferential shield excavation machine according to an embodiment, FIG. 7 is a view taken in the direction of the arrow in FIG. 6, and FIG. 8 is a circumferential shield excavation machine according to a second embodiment of the present invention. FIG. 9 is a longitudinal sectional view of the machine, FIG. 9 is a view taken in the direction of the arrow in FIG. 8, and FIG. The figure is a view taken along the arrow line XI--XI in FIG. 10. 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... Power excavator, 1
DESCRIPTION OF SYMBOLS 1... Screw auger, 12... Earth and sand guide member, 13... Earth and sand discharge means, 14... Nozzle,
15...vacuum pump, 16...rotary cutter, 17...screw conveyor.

Claims (1)

[Scope of Claims] 1. A circumferential shield excavator for excavating an enlarged tunnel approximately concentric with the small-diameter tunnel around the axial end face of a primary segment forming the small-diameter tunnel, the circumferential shield excavator In a circumferential shield excavator comprising a circumferential shield machine main body that is propelled substantially in the circumferential direction along the end face of a segment, and a jack that propels the circumferential shield machine main body, the front surface in the traveling direction of the circumferential shield machine A circumferential shield excavator characterized by a built-in power excavator on the side. 2. The circumferential shield excavator according to claim 1, wherein the power excavator includes earth and sand discharge means. 3. The circumferential shield excavator according to claim 2, wherein the power excavator is a screw auger or a rotary cutter. 4. Claim 2, wherein the earth and sand discharge means includes a nozzle that applies a jet jet of fluid to impart fluidity to the earth and sand, and a vacuum pump that sucks and removes the fluidized earth and sand. The circumferential shield excavator described. 5. The circumferential shield excavator according to claim 2, wherein the earth and sand discharge means has a screw conveyor for earth and sand.