JPH089275Y2 - Tail seal for cast-in-place lining shield method - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a tail seal for a cast-in-place lining shield construction method in which a shield machine is dug by pressure for placing concrete.

[Conventional technology]

The above-mentioned cast-in-place lining shield method is used, for example, as described in Japanese Patent Application No. 62-330145 relating to the application of the present applicant, between the end mold of the skin plate and the inner mold built in the ring shape. While pouring concrete by pouring concrete with a high pouring pressure into the void formed by the surrounding rock and the surrounding rock, the pouring pressure against the surrounding rock of the pouring concrete generated at that time And the pressure against the existing concrete lining is used as a reaction force, and this pressure is transmitted to the excavator through the end form frame formed in the shield tail part to propel the excavator. . In this construction method, when pouring concrete, the tail seal part is sealed to prevent concrete leakage inside the shield.

The known tail seal as described above is made of the material,
Through the rigidity due to the shape and the frictional force between the tail seal and the inner formwork, it has the effect of counteracting earth pressure, water pressure, especially concrete placing pressure, etc. It is known to form a backup ring between the frame and the tail seal.

[Problems to be solved by the device]

From the above, it can be said that the above-mentioned tail seal structure can only hold concrete pouring pressure, for example, a pressure of several Kg / cm ² , resulting in a significant decrease in work efficiency, and a pouring pressure higher than that. When pressed, concrete will flow out through the gap between the tail seal and the inner formwork. In order to further improve work efficiency, when the concrete pouring pressure is increased to, for example, 50 Kg / cm ² , the tail seal is deformed despite the backup ring being attached, and the deformed tail seal and inner formwork There was a problem that concrete leaked out from the gap.

An object of the present invention is to provide a tail seal for a cast-in-place lining shield construction method in which excavation of a shield machine is carried out by placing pressure of concrete.

[Means for solving the problem]

To achieve the above object, the tail seal for the cast-in-place lining shield method according to the present invention is to provide the tail seal with a backup ring having a follow-up backup ring for holding the high pressure generated by concrete casting.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings.

FIG. 1 is a sectional view showing a known shield machine main body A in a state of excavation work. The excavator main body A is composed of a shield head portion 1 and a shield tail portion 7 each having a cutter on the face side corresponding to the structure of a normal shield, for example, a mechanical shield. In the area of the shield tail portion 7 which is an extension of the shield head portion 1, a tail seal is inserted between the end formwork 10 for concrete pouring and the inner formwork 5, and the surrounding ground 11 The air space between the inner formwork 5 and the inner formwork 5 is sealed to the inside of the shield machine main body A.

The end formwork 10 for pouring concrete is provided with an opening for passing a conduit 3 for pumping concrete for pouring. Therefore, the conduit 3 is open in the space between the surrounding ground 11 and the inner form 5 in the end form 10 for placing concrete.

A high-pressure concrete pump 8 is provided on the abutment 9 in the internal air space C of the shield machine A, and the high-pressure concrete pump 8 is used for lining concrete pouring concrete pumping pipe 3 for concrete pouring. Ends with an opening formed in the end formwork 10.

As can be seen from FIG. 1, the excavation is performed by, for example, a full-section excavator, and the concrete 4 is placed in the air space 4 ′ formed in the inner formwork 5 and the surrounding ground 11 as the excavation progresses. The lining 6 is formed. At this time, since this concrete is pressed from the high-pressure concrete pump 8 through the concrete pressure-feeding conduit 3 for placing the lining concrete, the pressed-in concrete 4 is the above-mentioned space 4 '.
After that, it works to propel the shield machine A forward. Further, due to this pressure, the concrete itself receives a pressurizing action to form a dense lining 6 in the air space 4 '.

A known tail seal is shown in FIGS. 2 and 3.
In the tail seal structure B in FIG. 2, the tail seal is
13 has rigidity and tail seal due to its material and shape 13
It is recognized that it is further counteracted against earth pressure, water pressure, especially concrete pouring pressure, etc. through the frictional force between the inner formwork 5 and the inner formwork 5. Furthermore, in the tail seal structure E in FIG. 3, a backup ring 14 is formed between the end form 10 and the tail seal 13.

FIG. 4 shows a tail seal structure G according to the present invention. This tail seal is shown in an enlarged scale corresponding to the circled portion S of the shield machine A in FIG. This tail seal structure E is a tail seal
13, an inner mold 5, an end mold 10, a gap 16, a backup ring 14 and a follow-up backup ring 15. Backup ring 14 and tail seal 13 are end formwork
It is fixed to 10 with bolts 18. A tail seal 13 and a backup ring 14 formed so as to come into contact with the contact surface of the inner mold 5 in a curved shape are surrounded by three surfaces by the inner mold 5, and a follow-up backup ring 15 is provided.

Furthermore, in order to control the direction of the shield machine, a sufficient gap 16 is formed between the follow-up backup ring 15 and the inner formwork 5. Due to this gap 16, the contact surfaces of the backup ring 14 and the follow-up backup ring 15 and the contact surfaces of the tail seal 13 and the follow-up backup ring 15 are used as lubricants from the injection parts 17 and 17 'penetrating through the backup ring. For example, when Teflon or grease is injected, it allows the members to slide between their contact surfaces. That is, the follow-up backup ring 15 becomes slidable. Furthermore, the concrete of high pressure p, which is cast by the high-pressure pump 8, presses the tail seal 13 and thus the backup ring 14 via the follow-up backup ring 15. For this reason, the contact area between the follow-up backup ring 15 and the backup ring and the contact area with the follow-up ring 15 are large.

[Effect of device]

The tail seal for the cast-in-place lining shield method according to the present invention is provided with a back-up ring having a follow-up back-up ring that retains the high pressure generated by concrete placing, so that the shield machine controls the direction. In this case, even if intensive high-pressure concrete is poured into the tail seal, the follow-up backup ring that can slide freely securely fixes the tail seal and is integrally formed. Therefore, by increasing the contact area between the forming surface and the inner mold, the tail seal is not deformed even if the shield machine excavates vertically and horizontally, and the concrete does not leak from the tail seal and is stable. Can cast concrete. 50 kg / cm ²
The same operation is performed when concrete is placed under the above pressure.

[Brief description of drawings]

1 is a sectional view of a shield machine main body, FIGS. 2 and 3 are sectional views of a conventional tail seal structure, and FIG. 4 is a sectional view of a tail seal structure according to the present invention. Reference numerals in the figure 5 ... Inner formwork, 10 ... End formwork, 13 ... Tail seal,
14 …… Backup ring, 15 …… Following backup ring, 16 …… Gap, 17,17 ′ …… Injection part, P …… Concrete pressure.

Claims (1)

[Scope of utility model registration request] 1. A tail seal for a cast-in-place lining shield in which a shield machine is dug by a concrete placing pressure, and a follow-up backup ring for holding a high pressure (P) generated by concrete placing in a tail seal (13). (15)
A tail seal having a backup ring (14) provided with.