JPH0525989A - Vertical type shield method - Google Patents

Abstract

PURPOSE:To easily build a large depth shaft by providing a rough gravel taking-in mechanism in a soil discharging pipe utilizing a hollow part of a center shaft of a shield machine, assembling trapezoidal segments formed by equally dividing a circular ring from a starting shaft and giving reaction to the segment to excavate downward with fresh water excavation. CONSTITUTION:A shield machine 1 is held by machine holding mechanisms 7, 9, 10 of a starting shaft 5 to ensure vertical accuracy and initial excavation reaction through reaction mechanisms 4, 6. Next, trapezoidal segments 2 formed by dividing equally a circular ring from a position of the starting shaft 5 are assembled to give reaction to the segments 2 and continuously excavate vertically downward by fresh water excavation. Then when a soil discharging pipe is choked with rough gravel, the rough gravel is discharged to the rear side of a partition wall 11 by a rough gravel taking-in mechanism provided in a hollow part of a center shaft 13. At the step of excavation up to a predetermined depth, a cutter spoke 14 is pulled up and a bottom plate concrete 16 having a face plate 15 as a reinforcement is built in a pressure chamber 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft used for starting and reaching a deep shield tunnel, a ventilation shaft for a deep tunnel, or a shaft for constructing a deep foundation structure of a large-scale structure. The present invention relates to a vertical shield construction method used for constructing a deep shaft with a diameter of about 3 to 7 m and a depth of about 100 m.

[0002]

2. Description of the Related Art Conventionally, there are various techniques for constructing a vertical shaft depending on the depth and the plane size (caliber). First, the reverse construction method is effective for constructing a vertical shaft having a diameter of 1 to 2 m and a depth of up to about 50 m. The PC well method is effective when the diameter is increased to about 5 m and the depth is up to about 50 m.

For a shaft having a diameter of 5 m or more and a depth of 50 m or more, a construction method using a continuous underground wall is effective.

[0004]

In the above-mentioned reverse method, it is difficult to construct a vertical shaft through the gravel layer because the stability of the hole wall depends only on the stabilizing liquid (muddy water). However, the construction of deep shafts in fans and deltas, where the metropolitan areas of Japan are located, is a problem because it often penetrates the gravel layer.

The PC well method and the pneumatic caisson method are difficult to construct at a large depth of 50 m or more. Even if construction is possible, it is not rational in terms of construction period and construction cost. Therefore, the object of the present invention is to have a diameter of 3 to 7 m.
In a degree, safely the deep shaft of about 100m underground,
It is to provide a vertical shield construction method for constructing efficiently and accurately.

[0006]

As a means for solving the above-mentioned problems, the vertical shield construction method according to the present invention, as shown in the drawings, shows the shield machine 1 being vertically downwardly excavated from the ground surface. In the vertical shield construction method for constructing a vertical shaft, (a) a machine holding mechanism for supporting the starting vertical shaft 5 on the surface of the ground to prevent the shield machine 1 from sinking due to its own weight, and an initial reaction force for excavation. Providing a reaction force mechanism 4, b) The shield machine 1 is a hermetically sealed pressurizing type, and includes a center shaft type cutter portion.
Mechanism for picking up gravel in the waste pipe 19 that uses the hollow part of the
1, 22, and 23 are provided, and a segment 2 in which a circular ring is equally divided into trapezoids is assembled from the position of the starting shaft 5 and a reaction force is applied to the segment 2 to continuously dig vertically downward by fresh water excavation. C) When the shield machine 1 is excavated to a predetermined depth, the bottom slab concrete 16 is poured into the pressure chamber 12 at the tip of the shield machine underwater, and after the curing of the bottom slab concrete 16 is completed, the partition wall 11 of the shield machine 1 is completed. Dismantling and recovering the main equipment as much as possible.

Further, according to the present invention, the face plate 15 constituting the center shaft type cutter portion and the cutter spoke 14 can be separated from each other, and the cutter spoke 14 has a structure capable of expanding and contracting the diameter. Pressure chamber 12
Before the bottom slab concrete 16 is poured into the water, the diameter of the cutter spoke 14 is reduced, and then the cutter spoke 14 is pulled up to a position in the vicinity of the partition wall in the pressurizing chamber 12, which is below the position of the cutter spoke 14 in the pressurizing chamber 12. The bottom slab concrete is cast up to the level of 1 to bury the face plate 15 to construct the bottom slab concrete 16 using the face plate 15 as a reinforcing material, and the shield machine 1 is equipped with the water supply mechanism 18, and the water supply mechanism 18 adds water. Sending clean water into the pressure chamber 12 and advancing the excavation while taking in earth and sand and water from the hollow portion 19 of the center shut 13, and the shield machine 1
Is equipped with a pressure-type endoscopic camera 32 inserted into the pressurizing chamber 12 from the rear side of the partition wall 11. The construction of fresh water excavation of the shield machine 1, the excavation of the gravel layer and the incorporation of coarse gravel are monitored by a video monitor. It is also characteristic that the construction is advanced while doing so.

[0008]

The mechanical holding mechanisms 7, 9, 10 of the starting shaft 5 hold the shield machine 1 and ensure vertical accuracy. Further, the reaction force mechanisms 4 and 6 give an initial excavation reaction force. This shield machine 1 can excavate the gravel layer,
The dug out gravel is discharged together with the water flow through the earth discharge pipe 19 that uses the hollow portion of the center shut 13. If the soil discharge pipe 19 is clogged with coarse gravel,
Rubbish gravel intake mechanisms 21, 22, 2 provided in the soil discharge pipe 19
3 is discharged to the rear side 20 of the partition wall 11 in the shield machine 1 to clear the clogging.

The segment 2 in which a circular ring is divided into a number of trapezoids is easy to assemble in the axial direction of the shaft (vertically downward), and the shield jacks 30 and 30 'arranged axially symmetrically can be selected and used. Can be promoted. The vertical shield, which excavates the ground vertically downward, allows clear water excavation without fear of the ground collapsing. Therefore, there is no need to manufacture or treat muddy water (ground stabilization liquid). The skin plate of the shield machine temporarily holds the stability and water stop of the hole wall, and the passing portion of the shield machine is the segment 2 and its backfill material 3.
Performed by.

By constructing the slab concrete 16 at the bottom of the shaft, groundwater pressure and water stop can be completely treated.

[0011]

EXAMPLE An example of the present invention shown in the drawings will be described below.
FIG. 1 shows an overall construction outline of the vertical shield construction method according to the present invention. In the figure, 1 is a shield machine that digs vertically downward, 2 is an assembled segment, 3 is a backfill material, and 4 is a reaction force girder provided on the starting shaft of the ground surface.

2A, 2B and 2C show the details of the structure of the starting shaft 5 on the surface of the ground and the state of initial excavation of the shield machine 1.
When the outer diameter of the shield machine 1 is about 4 to 5 m, the diameter of the starting shaft 5 is a rectangle with one side of about 6 to 7 m, and the mountain retaining wall 6 is constructed by a pile pile column and the inside is excavated. Then, the starting shaft 5 is constructed. The starting shaft 5 has a depth of about 7 m, and floor slab concrete (abandoned concrete) 8 having an inlet 7 of the shield machine 1 is installed on the bottom of the hole. Further, in the case of the illustrated example, in consideration of the fact that the bottom of the hole is a soft ground that sinks due to the weight of the shield machine, ground improvement 9 is performed by adding and mixing treatment such as cement.

Therefore, the shield machine 1 installed vertically downward on the improved ground 9 is stably supported through the inlet 7 of the slab concrete 8 (machine holding mechanism). A reaction force girder 4 made of H-shaped steel is fixed to the upper end of the mountain retaining wall 6, and a segment 2 is assembled between the reaction force girder 4 and the shield machine 1. The initial excavation of the shield machine 1 is promoted through the segment 2 while ensuring a necessary and sufficient reaction force to the reaction force beam 4 (reaction mechanism). The reaction force girder 4 transmits the reaction force to the ground through the Yamadome wall 6. Before the shield machine 1 is assembled by assembling the segments 2 as described above, the starting shaft 5 is filled with backfill soil 10 on the outer periphery of the shield machine 1 as shown in FIG. The side surface of No. 1 is restrained, and vertical accuracy during propulsion is secured (machine holding mechanism).

The shield machine 1 is of a closed pressurizing type in which the inside of the pressurizing chamber 12 including the cutter portion on the tip side of the partition wall 11 is maintained at a water pressure equal to or higher than groundwater pressure. The water supply pipe 18 penetrates the partition wall 11 and pressurizes the chamber 1.
It is connected to 2. As shown in FIGS. 4A and 4B, the cutter portion is configured as a center shaft type in which a cutter spoke 14 having a structure capable of expanding and contracting diameter is attached to the tip of the center shaft 13. The face plate 15 has a structure separable from the cutter spokes 14 (a structure having a slit through which the cutter spokes 14 can move in and out).
It can be pulled up to a position in the vicinity of the partition wall 11 in FIG. 2 (FIG. 4A).
The face plate 15 is formed in a hemispherical convex shape (FIG. 4A) and is stiffened by several supporting walls 17 arranged in the radial direction. Therefore, it is mechanically advantageous when the face plate 15 and the support wall 17 are buried in the slab concrete and function as a reinforcing material.

A pipe material is used for the center shaft 13, and its hollow portion is also used as an earth discharging pipe 19. The earth and sand and gravel excavated by the cutter are carried with the water flow through the earth discharging pipe 19 and discharged to the ground. (Fig. 3). In the area of the rear space 20 above the partition 11 where workers enter, a gate valve 21 for partitioning the soil discharge pipe 19 is installed as a countermeasure against clogging of the soil discharge pipe 19 due to gravel. Gravel outlet 2 downstream of the valve 21
A gate valve 23 is provided which forms 2 in a lateral direction and partitions the opening. In other words, the mud pipe 13 due to the gravel
If it becomes clogged, the gate valve 21 should be fully closed to stop the water flow, and then the gate valve 23 should be opened to open the soil discharge pipe 13
The rubble clogged inside is taken out into the back space 20. After that, the gate valve 23 is fully closed again, and the other gate valves 2
1 is fully opened to restart the water flow.

The vertical shaft is excavated by the shield machine 1 having the above-mentioned structure by vertically driving downward by the propulsive force of the shield jack 30 having a reaction force against the assembled segment 2 and the fresh water excavation. This is because the vertical downward excavation does not cause any ground collapse. The removal of the earth and sand is performed by supplying fresh water into the pressurizing chamber 12 because it is necessary to secure a flow connection in the earth discharging pipe 19.

Segment 2 accompanying excavation of shield machine 1
As for the assembly of, the shape and structure of the segment piece is a shape obtained by equally dividing a circular ring into a trapezoid as shown in FIG.
As a structure, these segment pieces 2a and 2b are assembled in a circular ring by combining them in alternate directions (Fig. 6).
(See A). As shown in FIGS. 5A and 5B, the segment 2 is supported by the shield jacks 30 arranged axially symmetrically at a rate of two per one segment piece so as not to fall, and the reaction force that propels the shield machine 1. And the shield jacks 30 and 30 'are selected and used for continuous propulsion. That is, as shown in FIGS. 6A to 6D, as a feature of the trapezoidal segment piece, the segment 2 assembled in the circular ring has half the upright trapezoidal segment pieces 2a, and half the shield jacks 30 in the axially symmetrical arrangement. If it is supported by, the collapse can be completely prevented and the propulsive reaction force of the shield machine 1 can be secured. Then, as the next step, as shown in FIG. 6B, the inverted trapezoidal segment pieces 2b corresponding to half of the circular ring in the next step are installed in a portion between the shield jacks 30 which are currently working. The segment piece 2b is replaced by a shape in which the remaining half of the shield jacks 30 'are supported axially symmetrically (FIG. 6C). After that, the shield jack 30 '
Half of the upright trapezoidal segment pieces 2 that remain in the space between
By assembling a and repeating the process of reassembling the segment piece 2a so that it is supported by half of the shield jacks 30, the segment 2 can be supported and assembled and the shield machine 1 can be continuously driven. .

The state of excavation by the shield machine 1 is as shown in FIG.
The pressure type endoscopic camera 32 inserted in the inside 2 monitors the inside of the pressurizing chamber 12 visually by a monitor TV, and the construction of fresh water excavation and the excavation of the gravel layer are effectively performed. Thus, in the stage where the excavation of the shield machine 1 progresses to a predetermined depth and the bottom of the shaft is constructed, the cutter spokes 14 are first reduced in diameter as shown in FIG. Is pulled up to a position near the partition wall 11. Then, the bottom slab concrete is poured into the water from the cutter spokes 14 in the pressurizing chamber 12 to the following level while being replaced with fresh water, and the face plate 15 and the supporting wall 17 are buried to construct the bottom slab concrete 16. This bottom slab concrete 16 is a hemispherical face plate 15
Also, since the support wall 17 is used as a reinforcing material, it can sufficiently withstand a huge underground water pressure at a large depth.

After the curing of the slab concrete 16 is completed, the partition walls 11 are disassembled and the cutter spokes 14 and other main equipment are recovered. Then, if necessary, a secondary lining is applied inside the shield skin plate.

[0020]

EFFECTS OF THE INVENTION According to the vertical shield construction method of the present invention, it is possible to safely, economically and reasonably construct a deep shaft having a diameter of about 3 to 7 m and a depth of about 100 m. It contributes to the construction of a starting or reaching shaft for deep shield tunnels, a ventilation shaft for deep tunnels, and a shaft for deep foundation structures.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an overall image of an implementation state of a vertical shield construction method according to the present invention.

2A, 2B and 2C are a plan view and a vertical sectional view of a starting shaft portion.

FIG. 3 is a vertical sectional view showing an outline of the structure of a shield machine.

4A and 4B are vertical cross-sectional views showing an outline of the structure of the shield machine.

5A and 5B are a vertical sectional view and a bb arrow view schematically showing the relationship between the shield jack and the segments.

6A to 6D are explanatory views in which a segment assembling method and a support by a shield jack are developed.

FIG. 7 is an elevation view showing a construction state of bottom slab concrete.

[Explanation of symbols]

1 shield machine 5 starting shaft 4 Reaction force digit (reaction force mechanism) 13 Center shut 19 Exhaust pipe 2 segments 12 Pressurized chamber 16 Bottom slab concrete 11 partitions 14 Cutter spoke 15 face plate 18 Water supply pipe (water supply mechanism) 32 Endoscopic camera

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Iwamoto             2-5-14 Minamisuna, Koto-ku, Tokyo Stock Market             Takenaka Corporation Technical Research Institute (72) Inventor Yoshifumi Fujii             8-21-21 Ginza, Chuo-ku, Tokyo Stock market             Takenaka engineering works (72) Inventor Taizo Uchida             8-21-21 Ginza, Chuo-ku, Tokyo Stock market             Takenaka engineering works (72) Inventor Yasushi Kanzaki             8-21-21 Ginza, Chuo-ku, Tokyo Stock market             Takenaka engineering works

Claims (4)

[Claims] 1. A vertical shield construction method in which a shield machine is dug vertically downward from the ground surface to construct a vertical shaft. B) A mechanical support that constructs a starting vertical shaft on the ground surface and supports the shield machine so that it does not sink under its own weight. A mechanism and a reaction force mechanism for securing the initial reaction force for excavation are provided. (B) The shield machine is a closed pressurizing type, has a center shaft type cutter part, and uses the hollow part of the center shaft. The earth removal pipe is equipped with a mechanism for taking in gravel, and a circular ring is assembled from the position of the starting shaft into segments that are equally divided into trapezoids, and a reaction force is applied to the segments to vertically excavate with fresh water. ) When the shield machine has excavated to a specified depth, the bottom slab concrete is placed underwater in the pressure chamber at the tip of the shield machine, and the bottom slab concrete is cured. The vertical shield method is characterized by disassembling the bulkhead of the shield machine after completion and collecting the main equipment as much as possible. 2. A face plate constituting a center shaft type cutter portion and a cutter spoke can be separated, and the cutter spoke has a structure capable of expanding and contracting the diameter, and a bottom plate is provided in a pressure chamber at the tip of the shield machine. Before pouring concrete in water, reduce the diameter of the cutter spoke and pull it up to the position near the partition wall in the pressure chamber, and place the bottom slab concrete to the following level from the position of the cutter spoke in the pressure chamber. The vertical shield construction method according to claim 1, characterized in that the bottom plate concrete is constructed by burying the face plate and using the face plate as a reinforcing material. 3. The shield machine is provided with a water supply mechanism, which sends fresh water into the pressure chamber by the water supply mechanism and advances excavation while taking in earth and sand and water from the hollow portion of the center shaft. Vertical shield construction method described in 1. 4. The shield machine is equipped with a pressure type endoscopic camera inserted into the pressure chamber from the back side of the partition wall, and the construction of fresh water excavation of the shield machine, excavation of the gravel layer, and intake of coarse gravel are video. The vertical shield construction method according to claim 1, wherein the construction is advanced while monitoring the monitor.