JPH0455116Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a tail seal device for a shield excavator.

(Prior Art) The inventors of the present invention previously proposed in Japanese Patent Publication No. 54-33656 and Japanese Patent Application No. 61-158675 (Japanese Unexamined Patent Publication No. 63-14997) that After assembling the inner formwork and pouring concrete between the inner formwork, the shield tail, and the front of the existing lining concrete, a propulsive reaction force is applied to the cast concrete and the inner formwork respectively. proposed a tunnel construction method in which the shield excavator is propelled by a lining concrete jack attached to the shield excavator as well as a shield jack.

Therefore, the tail seal in conventional shield excavators is installed between the tail plate of the shield excavator and the outer surface of the segment, and is used to prevent leakage of backfilling material after segment assembly, maintain injection pressure, and pressurize. It is used for multiple purposes, such as preventing muddy water and groundwater from entering underground mines.

(Problems to be Solved by the Invention) In the tunnel construction method proposed by the present inventors, when the tail seal used in the conventional shield excavator is attached to the tail plate of the shield excavator, When placing lining concrete, when the shield excavator excavates, it becomes an obstacle to the flow of the poured concrete.

Also, for reinforcing steel assembly, concrete pouring, etc.
It is necessary to move the press ring, which also serves as the end formwork at the tip of the lining concrete jack, to the face side, and at this time, a gap occurs between the tail plate of the shield excavator and the poured concrete, and the same 〓There is a risk of groundwater intruding from the gap.

(Means for Solving the Problems) The present invention was proposed in order to solve these problems, and includes embedding an air supply pipe in the tail plate of the shield excavator body, and burying the air supply pipe inside the tail plate. The present invention relates to a tail seal device for a shield excavator, characterized in that an air outlet communicating with the air supply pipe is provided around the entire circumference of the shield excavator.

(Function) As described above, in the present invention, the air supply pipe is embedded in the tail plate, and the air outlet that communicates with the air supply pipe is arranged on the inner peripheral surface all around the tail plate. The plate has no protrusions on the inside, so when the poured lining concrete flows from the face side while being consolidated as the shield excavator excavates, the tail seal does not interfere with the flow of the concrete.

In addition, when moving the press ring that also serves as the end formwork at the tip of the lining concrete jack to the face side for reinforcing bar assembly, concrete pouring, etc., the air blower provided all around the inner circumferential surface of the tail plate is used. By supplying pressurized air from the outlet through an air supply pipe buried in the tail plate, and forming an air curtain inside the tail plate from the outlet, air can be generated between the tail plate and the poured concrete. Prevent groundwater from entering between the ground and the ground.

By keeping the blowing air pressure at the air outlet at a constant pressure, dewatering from the concrete that occurs when pressurizing the poured concrete while the shield excavator is propelled flows back to the air outlet. This is something that can be prevented.

(Example) The present invention will be described below with reference to the illustrated embodiments.

1 is the shield excavator main body, 2 and 3 are shield jacks and lining concrete jacks respectively installed on the ring girder 4, and the inner formwork 5 is assembled in the tunnel hole excavated by the shield excavator.
A lining concrete 8 is poured between the inner formwork 5, the tail plate 6, and the front surface of the existing lining concrete 7, and a propulsive reaction force is taken on the poured concrete 8 and the inner formwork 5. , the shield excavator main body 1 is propelled by the lining concrete jack 3 and the shield jack 2.

In the figure, 9 is a spreader at the tip of the shield jack 2, 10 is a press ring that also serves as the end formwork at the tip of the lining concrete jack 3, and is configured to slide airtight between the tail plate 6 and the spreader 9. There is.

An air supply pipe 11 is buried in the tail plate 6 along the longitudinal direction of the plate, and the tip of the air supply pipe 11 is connected to an annular pipe 11a extending around the entire circumference of the tail plate 6. It is connected to an annular air outlet 12 disposed around the entire circumference of the inner peripheral surface of the plate 6 .

In the figure, 13 is an air supply compressor, and 14 is a pipe 15 that connects the compressor 13 and the air supply pipe 11.
An exhaust valve 16 installed in the exhaust valve 16 is a pressure regulating device.

Since the illustrated embodiment is configured as described above, after the shield excavator is propelled, the lining concrete jack 3 When the press ring 10 that also serves as the end formwork is retreated toward the face side, a gap is created between the lining concrete 8 and the tail plate 6, as shown in t in Fig. 5, and pressure is applied from the gap. In order to prevent muddy water and groundwater from entering the mine, the air outlet 12 is
Pressurized air is jetted out to form an air curtain.

The pressure value of the blown air at this time is adjusted by the pressure regulator 15 so as to maintain it at a pressure value that can compete with the pressure value of muddy water, etc., and the air pressure increases due to the fluctuation of the interval. Therefore, avoid applying excessive pressure to the poured concrete.

The exhaust valve 14 is for removing excess air around the air supply pipe 11 and the air outlet 12 after the shield excavator starts digging and the poured concrete 8 is pressurized.

Further, as described above, by maintaining the pressure of the air blown from the air outlet 12 at a required value, as shown in FIG. This prevents dewatering from the concrete that occurs when pressurized from flowing back into the air outlet 12.

Note that, if necessary, a valve for preventing inflow of water from concrete, etc. may be provided in the air outlet 12.

(Effects of the invention) As described above, according to the invention, an air outlet is provided on the inner peripheral surface of the tail plate of the shield excavator body over the entire circumference of the plate, and the air outlet is embedded in the tail plate. By connecting to the air supply pipe, an air curtain is formed by the pressurized air blown out from the air outlet, and the space between the tail plate and the poured lining concrete is reduced.
This prevents the intrusion of groundwater, etc. from the ground, and allows efficient and stable shield excavation method to be carried out even in poor ground or ground with high water pressure.In addition, by having a structure with no protruding parts on the inside of the tail plate, the shield This prevents obstacles from occurring when fresh concrete is pressurized and flowed from the face side while the excavator is moving.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional side view showing an embodiment of the tail seal device for a shield excavator according to the present invention, and an enlarged view of part A in FIG. 7, and FIGS. 2 and 3 are arrows shown in FIG. View B-B view and arrow view C-C view,
Figure 4 is a perspective view showing details of the air outlet section, Figure 5
Figure 6 and Figure 6 are longitudinal side views showing the state of formwork, reinforcing bar assembly, concrete placement, curing, and shield excavator excavation, respectively, and Figure 7 is a shield excavator equipped with the device of the present invention. FIG. 3 is a vertical side view showing the working situation. 6... Tail plate, 11... Air supply pipe, 12
...Air outlet.

Claims (1)

[Scope of utility model registration request] An air supply pipe is buried in the tail plate of the main body of the shield excavator, and an air outlet communicating with the air supply pipe is arranged all around the inner peripheral surface of the tail plate. Tail seal device for shield excavator.