JP3083941B2 - Hazardous gas exhaust system in shield tunnel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for exhausting harmful gas generated from the ground in a shield tunnel.

[0002]

2. Description of the Related Art Today, a shield method is widely used for installing tunnels such as a subway, water and sewage, and a power communication cable in an underground space of a city. In the shield method, a shaft is built, a strong steel shell called a shield is inserted into the ground from the shaft, the ground is excavated in front of the space protected by the shield, and segments are assembled at the rear, In this method, the shield is advanced while the reaction force is applied to the segment, and the tunnel is expanded.

[0003]

The underground atmosphere in which the above-described shield method is constructed cannot be sufficiently ventilated by natural ventilation. Therefore, the geological conditions, shield scale, construction method, process, etc. must be carefully considered. Therefore, it is necessary to provide an appropriate ventilation system in the mine and secure a safe and sanitary working environment. In particular, when harmful gases such as flammable gas such as methane gas may be generated from the ground, a system that exhausts them sufficiently to prevent danger such as explosion is indispensable.

[0004] If flammable gas such as methane gas generated at the face can be collected and used as an energy source, it will also be useful for resource conservation. Care must be taken not to pollute the environmental air with the exhausted gas.

An object of the present invention is to provide a system capable of suitably exhausting harmful gas generated from the ground in a mine where the above-mentioned shield method is constructed.

[0006]

In view of the above, a chamber for collecting harmful gas is provided at an outlet of an earth removal conveyor for discharging earth and sand excavated with a face to a tail part of a shield in a shield tunnel. And a harmful gas treatment plant installed outside the mine. An exhaust line is formed, and a pump is installed in the exhaust line to exhaust the harmful gas collected in the chamber to the treatment plant. A gas exhaust system was configured.

The above exhaust system is used to exhaust methane gas in particular. Further, a sensor for detecting the methane gas concentration in the chamber is provided, and the bottom surface of the chamber is formed to be openable and closable, thereby increasing the methane gas concentration in the chamber. When the methane gas concentration became low, the bottom of the chamber was opened when the methane gas concentration became low. In addition, the exhaust line is arranged above the mine, and the exhaust line is provided with an intake port provided with a check valve. In addition, a methane aqueous solution is manufactured in the treatment plant.

[0008]

The harmful gas generated at the face will pass through the inside of the shield and attempt to flow out into the pit. Therefore, a harmful gas that is going to flow out of the shield tail portion is collected by a chamber provided at the outlet of the discharging conveyor, and the harmful gas is drawn into the exhaust line by operating the pump. Then, the harmful gas is sent to a processing plant and processed as needed.

[0009]

Embodiments of the present invention will be described below. First, an earth pressure shield method will be described with reference to FIG. Cutter 2 is mounted on the front of shield 1 and cutter 2
There is an earthen room 3 behind. At the approximate center of the earth chamber 3, an earth discharging conveyor 4 having an outlet at the tail of the shield 1 is provided.

[0010] Then, the shield 1 is inserted from the shaft 6 built in the ground 5, the earth and sand obtained by cutting the ground 5 with the cutter 2 is taken into the earth chamber 3, and the cut earth is used to oppose the pressure of the face. At the same time, the discharging conveyor 4 installed in the earth room 3
Accordingly, the basic principle is that the earth and sand 6 in an amount balanced with the propulsion amount are continuously discharged to the belt conveyor 7 and the shield 1 is propelled while stabilizing the face.

According to the present invention, in the shield method described above, a chamber 10 for collecting harmful gas is provided at the outlet of the earth discharging conveyor 4, and this chamber 10 and a harmful gas treatment plant 11 installed outside the mine. Are communicated through an exhaust line 12, and a harmful gas collected in a chamber 10 is exhausted to a processing plant 11 by operating a pump 13 interposed in the exhaust line 12. Hereinafter, a system for exhausting methane gas in a mine will be described as an example of the present invention.

First, the chamber 10 shown in FIG. 2 has a function of collecting methane gas 15 generated at the face and going to the mine from the exit of the earth discharging conveyor 4. On the ceiling of the chamber 10, a sensor 16 for detecting the methane gas concentration inside the chamber 10 is provided.
The bottom surface 17 of the chamber 10 is formed to be freely openable and closable, and the bottom surface 17 of the chamber 10 is open at all times (when the methane gas concentration in the chamber 10 is low), so that the cut sand discharged from the outlet of the discharging conveyor 4 can be removed. It falls under its own weight and is delivered to the belt conveyor 7. The methane gas 15, which is lighter than air, rises due to the difference in specific gravity and the negative pressure caused by the operation of the pump 13, and is drawn into the exhaust line 12 communicating with the upper part of the chamber 10.

FIG. 3 shows the sensor 16 and the bottom surface 1 of the chamber.
FIG. 7 is a block diagram showing a relationship 7. As shown in the figure, the methane gas concentration signal in the chamber 10 detected by the sensor 16 is input to the computer 18 and always (when the methane gas concentration in the chamber 10 is low)
The computer 18 issues a command to open the chamber bottom 17. On the other hand, when the sensor 16 detects that the methane gas concentration inside the chamber 10 has increased,
Is closed, and the chamber bottom 17 is closed by driving means (not shown).

As shown in FIG. 4, the exhaust line 12 is disposed above the well, and the inside of the chamber 10 is made negative pressure by the operation of the pump 13 described above.
It serves to draw in and exhaust the methane gas collected in the step. As shown in the figure, the exhaust line 12 is provided with a number of intake ports 20 each having a check valve. The negative pressure generated by the operation of the pump 13 causes the methane gas accumulated above the mine due to the difference in specific gravity with air. Is drawn into the exhaust line 12 from the intake port 20 together with the surrounding air, and is exhausted to the processing plant 11.

The treatment plant 11 plays a role of producing an aqueous methane solution by dissolving methane gas exhausted from the pit by an exhaust line 12 into water. As shown in FIG. 5, the distal end of an exhaust line 12 is opened below a processing plant 11 formed as a whole in a pressurized container by supplying compressed air by a compressor 21. The treatment plant 11 has an inlet pipe 22 and a drain pipe 2.
3 is connected, and a valve 24 is provided in the middle of the drain pipe 23. Further, a sensor 25 for detecting the methane concentration is disposed at the bottom of the processing plant 11.

Then, as shown in the figure, a mixed gas of methane gas and air is discharged from the exhaust line 12 in a state where the water 26 is pressurized and filled in the processing plant 11, so that the methane gas is dissolved in the water to form an aqueous methane solution. The sensor 25 detects that the concentration of the methane aqueous solution has reached a predetermined value.
, The valve 24 is opened, and the methane aqueous solution discharged from the drain pipe 23 is injected into the cylinder 27. The cylinder 27 filled with the methane aqueous solution is transported to, for example, a methane purification plant.

In the exhaust system according to the embodiment of the present invention having the above configuration, the methane gas generated at the face by excavating the ground 5 with the cutter 2 is removed by the earth discharging conveyor 4 together with the earth and sand. It is conveyed to the tail part of the shield 1 and enters the chamber 10 provided at the exit of the discharging conveyor 4.

When the sensor 16 disposed on the ceiling of the chamber 10 detects that the methane gas concentration is low, the bottom 17 of the chamber is in an open state, and the cut sand discharged by the discharging conveyor 4 is The methane gas is dropped by its own weight and discharged to the outside of the pit appropriately by the belt conveyor 7.
It is drawn inside.

On the other hand, if the sensor 16 detects that the methane gas concentration is high, the bottom surface 17 of the chamber is closed by a command from the computer 18 so that the inside of the chamber 10 is closed, and the methane gas with high concentration tries to flow into the pit. Is prevented. Thus,
The methane gas collected in the chamber 10 is drawn into the exhaust line 12.

As described above, the methane gas generated at the face is exhausted in the exhaust line 12 by the operation of the pump 13, and the methane gas accumulated in the upper part of the pit is also reduced by the action of the negative pressure together with the surrounding air at the intake port 20. , And is conveyed by being drawn into the exhaust line 12, so that a mixed gas of methane gas and air is released into the water 26 charged into the processing plant 11 under pressure.

The methane gas thus released is dissolved in water to produce an aqueous methane solution. When a predetermined concentration value is detected by the sensor 25, the valve 24 is opened and the aqueous methane solution is discharged from the drain pipe 23 to the cylinder 27. Is injected into. Thus, the methane aqueous solution filled in the cylinder 27 is easily transported to a methane purification plant or the like by a truck or the like, and is used as an energy source.

Although methane gas has been described as an embodiment of the present invention, the system of the present invention can also be used for a system for exhausting harmful gases other than methane gas. When exhausting harmful gas that is heavier than air, an exhaust line may be installed in the lower part of the mine, and the harmful gas may be sucked and exhausted from a suction port appropriately provided in the exhaust line below the mine.

[0023]

According to the present invention, it is possible to preferably exhaust harmful gas generated from the ground in the mine where the shield method is constructed, and to provide a safe and sanitary working environment.

[Brief description of the drawings]

[Fig. 1] Illustration of earth pressure shield method

FIG. 2 is an explanatory view of a chamber.

FIG. 3 is a block diagram showing a relationship between a sensor and a bottom surface of a chamber.

FIG. 4 is an explanatory view of an exhaust line.

FIG. 5 is an explanatory diagram of a processing plant.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shield 4 Discharge conveyor 10 Chamber 11 Processing plant 12 Exhaust line 13 Pump

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hideaki Tanaka 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Kashima Construction Co., Ltd. (72) Inventor Motohisa Okamoto 1-2-2 Moto-Akasaka, Minato-ku, Tokyo 7 Kashima Construction Co., Ltd. (58) Field surveyed (Int. Cl. ⁷ , DB name) E21F 1/00

Claims (5)

(57) [Claims] 1. A chamber for collecting harmful gas is provided at an outlet of a discharge conveyor for discharging earth and sand excavated by a cutting face to a tail portion of a shield in a shield tunnel, and the chamber is installed outside the chamber and the chamber. An exhaust system for harmful gases in a shield tunnel, wherein an exhaust line communicating with a harmful gas treatment plant is formed, and a pump for exhausting the harmful gas collected in the chamber to the treatment plant is interposed in the exhaust line. 2. The system according to claim 1, wherein the harmful gas is methane gas. 3. A sensor for detecting the concentration of methane gas in the chamber is provided, and the bottom of the chamber is formed to be openable and closable when the concentration of methane gas in the chamber becomes high. 3. A system according to claim 2, wherein the bottom of the chamber is opened when the harmful gas is discharged. 4. The exhaust line is disposed above the mine and an exhaust port provided with a check valve is provided in the exhaust line.
Or the exhaust system of harmful gas in the mine by the shield method of 3. 5. The exhaust system for harmful gases in a downhole of the shield method according to claim 2, wherein a methane aqueous solution is produced in the treatment plant.