JP3120244B2 - Installation start method of shield machine of vertical shield method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for installing and starting a shield machine which is carried out in a vertical shield construction method for constructing a shaft.

[0002]

2. Description of the Related Art The usual horizontal shield construction method has a large number of construction examples, and the technology relating to the installation and start of a shield machine is almost established. However, there have been few construction examples of the vertical shield method, and no technology has been established for the installation and start of the shield machine.

[0003]

[Problems to be Solved by the Invention] In the vertical shield construction method, the propulsion and excavation direction of the shield machine is vertically downward, and the start is started from the surface of the ground. Need to be prepared only for the start, etc., are significantly different from the case of the normal horizontal shield method.

[0004] Regarding the installation start of the vertical shield machine, the state of the ground to be constructed, particularly the state of the ground near the ground surface, becomes a serious problem. In the case of the vertical shield construction method, when the shield machine is installed on the ground surface, there are problems in the method of supporting the shield machine and how to take the propulsion reaction force at the time of starting. For example, when the installed capacity of the shield machine is insufficient due to the soft ground and the shield machine sinks by its own weight, it is even necessary to support the shield machine in a direction opposite to the starting direction (vertically upward). Even if it is not necessary to support the shield machine, if the cutter head of the shield machine has an excessive ground pressure due to its own weight, etc., the shield machine body will rotate together with the rotation of the cutter head and rolling will occur. In some cases, initial propulsion and excavation of the shield machine may become difficult.

Accordingly, it is an object of the present invention to provide a method of installing and starting a shield machine which is useful for construction of a vertical shield method.

[0006]

As a means for solving the above-mentioned problems of the prior art, a method for installing and starting a shield machine of a vertical shield method according to the present invention is described as follows. In a vertical shield construction method in which a machine 1 is excavated vertically downward from the surface to construct a shaft, a) a start shaft 2 having a predetermined depth is constructed on the surface, and a shield machine 1 is provided at the bottom of the start shaft 2 Constructing a slab concrete 4 having an opening 3 having a diameter slightly larger than the diameter, and mounting and supporting the shield machine 1 in the starting shaft 2 in a vertical arrangement facing the ground 10 immediately below through the opening 3; Backfill soil in the starting shaft 2 on the outer circumference of the machine 1
And from the inside of the shield machine 1 vertically upward segment 6
And then filling backfill soil 7 also in the start shaft on the outer periphery of the segment 6; c) constructing a reaction force table 8 on the top of the start shaft 2 for applying a propulsion reaction force to the top of the segment 6; And then launching the shield machine 1 vertically downward.

The present invention also relates to a ground 1 at the bottom of the starting shaft 2.
In the case where 0 is a soft ground where the shield machine 1 sinks under its own weight, the ground 10 is improved, the floor slab concrete 4 is applied, and the shield machine 1 is installed and supported. After applying an anti-friction agent to the outer surface of the skin plate, the outer periphery thereof is filled with backfill soil 5, and the backfill soil 5, 7 filled on the outer circumference of the shield machine 1 and the segment 6 is subjected to improvement. The power platform 8 is constructed by welding the reinforcing steel to the reinforcing steel or the H-steel core material of the retaining wall 9 of the starting shaft 2 and is constructed as a reinforced concrete structure integrated with the retaining wall 9. After filling the backfill soil 5 with water, injecting water into the vertical shaft 2 to a level sufficient to exert a predetermined buoyancy on the shield machine 1, and then preparing to start the shield machine 1 vertically downward; Also special To.

[0008]

The shield machine 1 having the vertical arrangement facing the ground 10 directly below the floor 10 through the opening 3 of the floor slab concrete 4 of the starting shaft 2, the ground 10 and the floor slab concrete 4 and the backfill soil 5, or the surrounding pit soil It is firmly supported by the support from the wall 9 and can even be supported in the lifting direction in some cases. The segment 6 assembled upward from the inside of the shield machine 1 is also supported by the backfill soil 7 filled in the outer periphery. The propulsion reaction force of the shield machine 1 at the time of starting is sufficiently secured by the reaction force table 8 and the shaft retaining wall 9 on the segment 6 via the segment 6.

In particular, since the water injected into the starting shaft 2 is lifted by applying buoyancy to the shield machine 1, the ground pressure due to its own weight and the like is reduced, so that the torque required for rotating the cutter head is greatly reduced. And the shield machine 1 is firmly held by the backfill soil 5 and the frictional force,
No rolling occurs.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A and FIG. 1B show a first embodiment of the present invention.
The stage at which the starting shaft 2 was constructed is shown. In this method, a soil retaining wall 9 is constructed by a well-known soil column method, and the inside thereof is excavated and bulges 11 are sequentially installed. The bulge 11 is provided with a shield machine at the center by an oblique fire cutoff beam 12. The shaft 2 is excavated to a depth required for the preparation for starting the shield machine, leaving a space for obtaining it.
The bottom of the start shaft 2 is larger than the outer diameter of the shield machine by 2 mm.
Floor slab concrete (discarded concrete) 4 having an opening 3 having a large diameter of about 0 to 30 cm at the center is constructed. However, when the ground 10 at the bottom of the shaft is soft ground such that the shield machine 1 installed thereon sinks under its own weight, the ground is improved by, for example, a mixing method using a known stabilizer, and the improved ground is used. Floor slab concrete 4
Is constructed.

FIG. 2 shows a state in which the shield machine 1 is built into the start shaft 2 and the back shaft 2 on the outer periphery of the shield machine 1 is filled with backfill soil 5 to support the shield machine 1. Is shown. The shield machine 1 is installed in the starting shaft 2 in a vertical arrangement in which the tip end (cutter portion) faces the ground 10 directly below through the opening 3. Although not shown in detail, the shield machine 1 is supported by a support member that takes a reaction force on the shaft shaft retaining wall 9. Alternatively, depending on the support capacity of the ground 10, support for lifting the shield machine 1 upward is also performed. In addition,
Before filling the backfill soil 5, a friction reducing lubricant is applied to the outer surface of the skin plate of the shield machine 1 to reduce the resistance at the time of starting and facilitate the starting as required. Alternatively, water is injected into a shaft 2 filled with backfill soil 5 up to a predetermined level, and the buoyancy causes the shield machine 1
The tip contact pressure is reduced, the resistance torque of the excavation caused by the rotation of the cutter head is reduced, thereby preventing the rolling of the shield machine body, etc., and ensuring the vertical accuracy.

FIG. 3 shows the assembly of several rings 6 to the desired height vertically above the position of the shield jack in the shield machine 1 vertically installed and supported in the starting shaft 2 as described above. A backfill soil 7 is also filled in the starting shaft 2 on the outer periphery of the starting shaft 2 to support the segment 6, and a reaction force table 8 for applying a propulsive reaction force to the top of the segment 6 is constructed above the starting shaft 2, This is just the stage when the shield machine 1 is ready to start. If the backing soil 5 or 7 is considered to be insufficient in supporting capacity of the shield machine 1 and Segummet 6, for example, a known mixing treatment method by injecting a stabilizing material or the like is performed to provide a stable and stable support. Close.

The reaction table 8 can be installed by erection of one or several H-section steels or the like, but in the embodiment of FIG. 3, it is constructed as a reinforced concrete structure. In this case, the reinforcing bar of the reaction table 8 is welded to the reinforcing bar of the shaft shaft retaining wall 9 or the H steel core material, and is constructed as a reinforced concrete structure that is integrated with the retaining wall 9 in a stressed manner. The joint bolts of the uppermost segment ring are embedded in the concrete of the reaction table 8 and also integrated.

After all the above preparations are completed, the shield machine 1 is started. The propulsion reaction force at the time of starting is secured by the reaction force table 8 and the retaining wall 9 via the segment 6. In the case of the vertical shield method, the shield machine 1 is a closed pressurized type and is excavated on the basis of freshwater excavation. In this case, when the position of the shield machine 1 at the time of starting is above the groundwater level, excavation is performed while pouring fresh water. When the water level falls below the groundwater level, excavation will proceed while adjusting the water injection.

[0015]

[Effects of the present invention] According to the method of installing and starting the shield machine of the vertical shield method according to the present invention, the installation and support of the shield machine 1 can be reliably and easily performed according to the state of the ground 10 to be constructed. Also, there is no problem in securing the propulsion reaction force at the start, which contributes to the safe and stable construction of the vertical shield method.

[Brief description of the drawings]

1A and 1B are a plan view and a vertical sectional view of a starting shaft.

FIG. 2 is a sectional view of a starting shaft on which a shield machine is installed.

FIG. 3 is a cross-sectional view of a state in which the shield machine is ready to start.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shield machine 2 Starting shaft 3 Opening 4 Floor slab 10 Ground 5, 7 Backfill soil 6 Segment 8 Reaction bed 9 Earth retaining wall

Continuing from the front page (72) Inventor Takafumi Shimokawachi 2-5-1 Minamisuna, Koto-ku, Tokyo Inside Takenaka Corporation Technical Research Institute (72) Inventor Yoshifumi Fujii 8-2-11, Ginza, Chuo-ku, Tokyo Stock Company Takenaka Civil Engineering Co., Ltd. (72) Inventor Hideharu Komai 8-21-1, Ginza, Chuo-ku, Tokyo, Japan Takenaka Civil Engineering Co., Ltd. (72) Inventor Takao Akatsu 8-2-1, Ginza, Chuo-ku, Tokyo, Japan 58) Field surveyed (Int. Cl. ⁷ , DB name) E21D 5/04 E21D 9/06 301 E21D 1/08 E21D 1/03

Claims (5)

(57) [Claims] 1. A vertical shield construction method in which a shield machine is excavated vertically downward from the ground surface to construct a shaft, a) a start shaft having a predetermined depth is constructed on the ground surface, and a shield machine is provided at the bottom of the start shaft. Constructing floor slab concrete having an opening having a diameter slightly larger than the outer diameter of the shield machine, and installing and supporting the shield machine in the starting shaft in a vertical arrangement facing the ground immediately below through the opening; Fill the back shaft with backfill soil, assemble the segment vertically from inside the shield machine,
Then, filling backfill soil into the start shaft on the outer periphery of the segment; and c) constructing a reaction table for applying a propulsion reaction force to the top of the segment above the start shaft, and then starting the shield machine vertically downward. A method of installing and starting a shield machine using a vertical shield method, characterized in that: 2. In the case where the ground at the bottom of the starting shaft is soft ground such that the shield machine sinks under its own weight, the ground should be improved, and then the slab concrete should be constructed and the shield machine should be installed and supported. 2. The method according to claim 1, further comprising the steps of: 3. The method according to claim 1, wherein the outer surface of the skin plate of the shield machine is coated with a lubricant, and the outer periphery thereof is filled with backfill soil, and the backfill soil filled on the outer periphery of the shield machine and the segment is improved. A method for installing and starting a shield machine using the vertical shield method according to claim 1. 4. The reaction bed is constructed by welding a reinforcing bar to a reinforcing bar or an H steel core material of a retaining wall of a starting shaft, and is constructed as a reinforced concrete structure integrated with the retaining wall. 1. The method of installing and starting the shield machine of the vertical shield method described in 1. 5. The method according to claim 5, wherein after the backfill soil is filled in the start shaft, water is injected into the shaft in a level sufficient to exert a predetermined buoyancy on the shield machine, and then the shield machine is started vertically downward. The installation start method of a shield machine of a vertical shield method according to claim 1, characterized in that: