JP2583724B2 - Harmful gas leakage inflow prevention device for shield machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing harmful gas from leaking into a shield machine.

[0002]

2. Description of the Related Art In shield construction, FIGS.
As shown in FIG. 2, a mud pipe 6 pressurizes and sends a mud to a chamber 5 between a bulkhead 3 and a shield cutter 4 provided at a front portion of a shield machine body 2A of a shield machine 1A.
Excavated soil is discharged through a mud pipe 8. Therefore,
No gas flows from the shield cutter 4 side into the shield machine 1A, that is, into the pit.

[0003] On the other hand, the rear part of the shield machine 1A is hermetically sealed by a tail seal 10 so that muddy water and gas do not flow into the pit from the gap between the shield machine body 2A and the segment 22. In the drawing, reference numeral 23 denotes a shield jack, 24 denotes a cutter driving motor, 25 denotes an agitator,
6 is an elector, 27 is a perfect circle holding device, and 28 is a simultaneous back-filling injection device.

[0004]

SUMMARY OF THE INVENTION Conventional tail seal 1
0 is useful because it has a function of blocking muddy water. However, the function of sealing a gas having good permeability is insufficient, so that entry into the downhole cannot be prevented. In the unlikely event that the gas
In the case of combustible gas, there is a risk of causing a gas explosion in the mine, and in the case of other gases, there is a risk of causing an oxygen deficiency accident in the mine.

Further, as disclosed in Japanese Patent Application Laid-Open No. 57-130699, a plurality of seal members are interposed between the body of the shield machine and the segments, and the space formed by the seal members is provided with water pressure and pressure. There has been proposed an apparatus in which an intermediate pressure of the internal pressure is supplied to prevent reversal of a seal member.

Although this technique is effective for preventing inflow of muddy water, the function of sealing against gas is still not sufficient simply by preventing the reversal of the sealing member.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for preventing harmful gas from leaking and flowing in a shield machine for preventing harmful gas from entering a downhole from the tail seal side.

[0008]

According to the present invention, a tail seal is interposed between a shield body and a segment,
In a shield machine that pressurizes and sends a chamber between a bulkhead and a shield cutter with a mud pipe and discharges excavated soil with a mud pipe, the shield machine body and the segment are arranged closer to the bulkhead than the tail seal. An elastic sealing material is provided therebetween, one end of the elastic sealing material is fixed to the shield machine body, and the other end is pressed against the segment by a pressing tube supported by a tube pressing member protruding from the shield machine body,
The muddy water of the drainage pipe is pressure-fed through a filter to the lower part of the annular chamber defined between the elastic seal material and the tail seal, and the muddy water at the top of the annular chamber is drained by the drainage pipe. Water under pressure.

According to the apparatus of the present invention, the elastic sealing material is pressed against the segment by the pressing tube, and the elastic sealing material is pressed against the segment also by the muddy water taken into the annular chamber from the drain pipe, thereby forming the elastic sealing material. Increase airtightness. Further, even if gas invades the annular chamber, the invading gas accumulates at the top of the annular chamber and is discharged through a drain pipe. Therefore, invasion of gas into the downhole is reliably prevented.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a shield machine 1 provided with the device according to the present invention, and the portions corresponding to those in FIG.

In FIG. 1, an elastic sealing material 11 is interposed between the shield body 2 and the segment 22 on the bulkhead 3 side with respect to the tail seal 10, and one end of the elastic sealing material 11 is connected to the shield body. An annular chamber 12 is fixed to the section 2, and the sealing members 10 and 11, the shield body 2 and the segment 22 define an annular chamber 12. Further, a tube pressing member 13 is protrudingly provided on the shield body 2, and between the pressing member 13 and the elastic sealing member 11,
A pressing tube 14 is interposed. The pressing tube 14 is pressurized and the lip 11a of the elastic seal 11 is
Is pressed against the segment 22 and the pressing tube 14
Supports the reaction force at that time.

The lower part of the annular chamber 12 is connected to an upstream side of a sludge pipe 8 provided with a sludge pump 9 by a pipe 15, and a filter 16 and a pump 17 are interposed in the pipe 15. I have. Further, the top of the annular chamber 12 is connected to a downstream side of a connecting portion of the pipe 15 of the mud pipe 8 by a pipe 18 via a pump 19. By providing the filter 16,
Prevents the pipeline from being blocked by the mud of the wastewater. Reference numeral 7 in the drawing is a mud pump.

Next, the operation will be described. At the time of excavation, the pumps 7 and 9 are operated to excavate in a known manner, and the excavated soil is discharged.

At the same time, the pumps 17, 19 are operated. The elastic sealing material 11 is supported by a tube pressing member 13 and is pressed by a pressing tube 14 which has been pressurized in advance, and the lip portion 11a is pressed against the segment 22 to achieve airtightness. Further, a part of the excavated soil containing water in the drainage pipe 8 is removed by the filter 16 via the pipe line 15 to become muddy water 20, and is pumped to the annular chamber 12,
It promotes the air-tight action of the elastic sealing material 11. As a result, even if gas A enters the annular chamber 12 from the gap between the tail seal 10 and the segment 22, the muddy water 20 and the elastic sealing material 1
1 prevents entry into the mine.

The gas A that has entered the annular chamber 12 accumulates at the top of the annular chamber 12 and is discharged along with the muddy water 20 through the pipeline 18 and then through the drainage pipe 8 to the outside of the pit.

[0017]

According to the present invention, the elastic sealing material is pressed against the segment by the pressing tube to increase the airtightness of the elastic sealing material, and furthermore, the annular chamber defined between the elastic sealing material and the tail seal. The pressurized water is supplied through the filter to the mud from the exhaust pipe, thereby promoting the airtightness of the elastic sealing material.
The elastic sealing material and the pressurized mud in the annular chamber prevent harmful gas from entering the pit covered with the segment from the tail seal side.

Even if gas enters the annular chamber through the gap between the tail seal and the segment, the gas accumulates at the top of the annular chamber and is discharged to the outside of the pit together with mud via a drain pipe.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a shield machine provided with a device according to the present invention.

FIG. 2 is a side sectional view showing a conventional shield machine.

FIG. 3 is a front view of FIG. 2;

[Explanation of symbols]

 A: Gas 1, 1A: Shield machine 2, 2A: Shield machine body 3: Bulkhead 4: Shield cutter 5: Chamber 6: Mud pipe 7 ...・ Sludging pump 8 ・ ・ ・ Sludging pipe 9 ・ ・ ・ Sludging pump 10 ・ ・ ・ Tail seal 11 ・ ・ ・ Elastic seal 11a ・ ・ ・ Lip 12 ・ ・ ・ Annular chamber 13 ・ ・ ・ Tube holding member 14 ... Pressing tubes 15,18 ... Pipeline 16 ... Filters 17,19 ... Pump 20 ... Muddy water 22 ... Segment 23 ... Shield jack 24 ... Cutter drive motor 25 ... Agitator 26 ... Electa 27 ... Circularity holding device 28 ... Simultaneous back-filling injection device

Claims (1)

(57) [Claims] 1. A tail seal is interposed between a shield machine body and a segment, a chamber between a bulkhead and a shield cutter is pressurized and sent by a mud pipe, and excavated soil is discharged by a mud pipe. In the shield machine, an elastic seal material is provided between the shield machine body and the segment on the bulkhead side with respect to the tail seal, one end of the elastic seal material is fixed to the shield machine body, and the other end is shielded. The segment is pressed against the segment by a pressing tube supported by a tube pressing member protruding from the body of the machine, and muddy water of the drainage pipe is poured into a lower portion of an annular chamber defined between the elastic seal material and the tail seal. A device for preventing harmful gas leakage and inflow of a shield machine, wherein pressurized water is supplied through a filter and muddy water at the top of the annular chamber is supplied under pressure to the drainage pipe.