Explosion-proof device and construction method for earth pressure balance shield construction in gas tunnel

Abstract

The present invention discloses an explosion-proof device and construction method for earth pressure balance shield construction in a gas tunnel, which specifically includes a cutter head, a soil chamber, a front shield, a middle shield, a shield tail, a conveying mechanism and a gas explosion-proof device; a shield tail seal is provided at the shield tail, and a hinged seal is used at the shell hinge of the middle shield and the shield tail; a sealing device is provided at the joint of the pipe segment; the conveying mechanism includes a screw conveyor and a belt, and the screw conveyor is used to convey the slag in the soil chamber, and the slag falls onto the belt; the main body of the gas explosion-proof device is provided at the rear of the shield main machine and the trolley area. The present invention provides an explosion-proof device and construction method for earth pressure balance shield construction in a gas tunnel. The high-concentration gas released from the main gas overflow point during shield construction is diluted to a safe concentration range and exhausted to the full explosion-proof equipment area at the rear of the shield trolley through an explosion-proof fan, thereby reducing the risk of gas explosion in the shield main machine and the trolley.

Description

Technical Field

[0001] The invention relates to the field of gas tunnel construction, and in particular to an explosion-proof device and a construction method for gas tunnel earth pressure balance shield construction. Background Art

[0002] Earth pressure balance shield is widely used in tunnel construction due to its advantages such as small working pit area, fast construction progress, low equipment cost and high safety, and has the tendency to completely replace traditional tunnel construction by dark excavation method. Some tunnels have gas due to various reasons, and gas explosion is extremely powerful. Gas explosion must meet three basic conditions at the same time: first, the gas concentration is within the explosion limit, generally 5% to 16%; second, the oxygen concentration in the mixed gas is not less than 12%; third, there is a high-temperature fire source with sufficient energy, generally 650℃ to 750℃. The goal of gas explosion prevention is basically to control conditions one and three.

[0003] Since there are too many electrical equipment in the shield machine and the trolley, it is difficult to design them into a fully explosion-proof state. Management and technical personnel are worried that when the gas concentration in the shield and the trolley is high and the contactor ignites, it will cause a gas explosion. Therefore, the construction method in high-gas strata and gas-outburst strata still generally adopts the dark excavation method.

[0004] During the construction of the earth pressure balance shield, the locations where gas enters the tunnel are: the slag outlet of the screw conveyor, the hinged seal, the shield tail seal, and the segment joints. Since the hinged seal, the shield tail seal, and the segment joints all use sealing devices, the amount of gas infiltration can be basically ignored if the sealing devices are not damaged. Therefore, during the construction of the earth pressure balance shield, the main location where gas enters the tunnel is the slag outlet of the screw conveyor.

[0005] The slag is wrapped with gas and falls into the belt through the slag outlet of the screw conveyor, and the slag is spread flat on the belt. Most of the gas is immediately released into the air nearby (the slag outlet of the screw conveyor), and the slag and a very small part of the gas wrapped in the slag diffuse into the trolley or are conveyed to the slag car behind the shield machine trolley through the belt. There are a large number of electrical equipment without explosion-proof functions in the shield machine and the trolley. If the concentration of gas released into the air reaches 5% to 16%, it is easy to cause a gas explosion. In a low-gas tunnel, if the concentration of gas released near the slag outlet of the screw conveyor reaches the gas explosion concentration, it may also cause a gas explosion. Whether it is a low-gas, high-gas or gas-protruding tunnel, the prerequisite for using earth pressure balance shield construction is to find an effective method to ensure that the gas concentration in the shield host and trolley without explosion-proof capability is controlled below 0.5% (gas explosion safety factor is 10) in real time. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an explosion-proof device and construction method for earth pressure balance shield construction in a gas tunnel, which is used to prevent high-concentration gas released from the main gas overflow point (slag outlet of the screw conveyor) during shield construction from diffusing into the shield main machine and the trolley, thereby reducing the risk of gas explosion in the shield main machine and the trolley.

[0007] The objective of the present invention is achieved through the following technical solutions:

[0008] Gas tunnel earth pressure balance shield construction explosion-proof device, including cutter head, soil cabin, front shield, middle shield, shield tail, conveying mechanism and gas explosion-proof device;

[0009] The cutterhead is set in front of the soil cabin, and the soil cabin is set in the front shield. The cutters on the cutterhead cut off the debris on the front tunnel face, and the debris enters the soil cabin;

[0010] The middle shield is between the front shield and the tail shield. A propulsion cylinder and / or a segment assembler are arranged in the middle shield and the tail shield. A tail shield seal is arranged at the tail shield. A hinged seal is adopted at the shell hinge of the middle shield and the tail shield. A sealing device is arranged at the segment joint.

[0011] The conveying mechanism includes a screw conveyor and a belt. The screw conveyor is used to convey the slag in the soil compartment. The screw shaft of the screw conveyor rotates to convey the slag in the soil compartment to the slag outlet of the screw conveyor with the rear gate of the screw conveyor opened. The slag falls onto the belt, and the belt transports the slag to the slag car in the trolley.

[0012] The main body of the gas explosion-proof device is set at the rear of the shield main machine and the trolley area; during the shield construction process, the use of the gas explosion-proof device ensures that the gas concentration in the shield main machine area and the shield trolley area is within a safe range.

[0013] As a preferred method, the gas explosion-proof device is used to dilute the high-concentration gas released from the slag outlet of the screw conveyor to a safe concentration range and exhaust it through an explosion-proof fan to the fully explosion-proof equipment area at the rear of the shield trolley, reducing the risk of gas explosion in the shield main unit and trolley.

[0014] As a preferred embodiment, the gas explosion-proof device includes an exhaust pipe, an explosion-proof fan, an air intake channel and a gas sensor;

[0015] The gas sensor is used to detect the gas concentration, the exhaust pipe is used to exhaust the gas, and the explosion-proof fan provides the power for exhaust.

[0016] As a preferred embodiment, an exhaust duct is arranged above the air intake channel and a thin plate is arranged below the air intake channel. The thin plate is connected to the belt through a flexible seal. Except for the air inlet and the air outlet connected to the exhaust duct, the rest of the air intake channel is sealed to form a sealed space.

[0017] As a preferred method, the flexible seal member adopts a rubber sealing plate, which has good sealing effect, wear resistance and long service life. One end of the rubber sealing plate is fixed to the thin plate (may be bonded), and the other end of the rubber sealing plate should be close to the belt during use.

[0018] As a preferred embodiment, a main roller and side rollers are arranged below the belt, the main roller is arranged in the middle, and side rollers are arranged on both sides of the main roller.

[0019] As a preferred embodiment, the main roller and the side rollers are mounted on a support frame. In addition, the support frame is also used to support the thin plate.

[0020] As a preferred embodiment, a gas sensor is installed in the sealed space of the slag outlet of the screw conveyor, at the rear opening of the sealed space, in the exhaust duct, and at the end of the exhaust duct.

[0021] As a preferred embodiment, an explosion-proof fan is installed on the exhaust duct, an air intake port is arranged on one side of the explosion-proof fan, and an air outlet is arranged on the other side of the explosion-proof fan.

[0022] As a preferred method, the explosion-proof fan is set in the shield trolley area, a section of the exhaust pipe connected to the explosion-proof fan is connected to the sealed space, and the air outlet of the other section of the exhaust pipe connected to the explosion-proof fan is set in the explosion-proof area. The explosion-proof construction method of the earth pressure balance shield construction of the gas tunnel is to turn on the explosion-proof fan before the shield screw conveyor discharges slag, and the explosion-proof fan draws the gas in the sealed space of the screw conveyor discharge port to the rear of the shield trolley;

[0023] When negative pressure is formed in the sealed space, air outside the rear opening of the sealed space enters the sealed space;

[0024] When the screw conveyor is discharging slag, the gas released from the slag at the slag outlet and the gas entering from the rear of the sealed space are sucked away by the explosion-proof fan, which not only dilutes the gas released from the slag outlet but also ensures that the released gas does not spread in the shield main machine and the trolley, ensuring that the gas concentration in the shield main machine and the trolley is within the safe concentration range.

[0025] The beneficial effects of the present invention are as follows: the present invention provides an explosion-proof device and construction method for earth pressure balance shield construction in a gas tunnel. The high-concentration gas released from the main gas overflow point (slag outlet of the screw conveyor) during shield construction is diluted to a safe concentration range and then pumped to the full explosion-proof equipment area at the rear of the shield trolley through an explosion-proof fan, thereby reducing the risk of gas explosion in the shield mainframe and trolley. This invention is suitable for earth pressure balance shield construction in low-gas, high-gas and gas-prone strata, and is also suitable for coal mining tunnel construction and coal mining operations, and has great promotion prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is the general schematic diagram of the earth pressure balance shield;

[0028] Figure 2 This is a schematic diagram of an earth pressure balance shield explosion-proof device;

[0029] Figure 3 is a cross-sectional view of the air inlet;

[0030] In the figure, 1-cutter head, 2-soil compartment, 3-front shield, 4-middle shield, 5-thrust cylinder, 6-hinged seal, 7-shield tail, 8-segment assembly machine, 9-shield tail seal, 10-segment, 11-segment joint, 12-screw conveyor, 13-rear gate of screw conveyor, 14-slag outlet of screw conveyor, 15-belt, 16-gas explosion-proof device, 17-shield main machine area, 18-shield trolley area, 19-explosion-proof area, 20-first gas sensor, 21-exhaust port, 22-sealed space, 23-second gas sensor, 24-air inlet, 25-explosion-proof fan, 26-exhaust duct, 27-third gas sensor, 28-fourth gas sensor, 29-thin plate, 30-support frame, 31-rubber sealing plate, 32-side roller, 33-main roller, 34-slag. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it is necessary to understand that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present invention, unless otherwise clearly specified and limited, if a first feature exists above or below a second feature, it may include that the first and second features are in direct contact, or it may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature is above, above and above the second feature, including that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. If the first feature exists below, below and below the second feature, it includes that the first feature is directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0036] Embodiment 1

[0037] During the construction of the earth pressure balance shield in a gas tunnel, the locations where gas enters the tunnel include the hinge seal 6, the shield tail seal 9, the pipe segment joint 11 and the screw conveyor slag outlet 14. Although there is a possibility of gas leakage at the hinge seal 6, the shield tail seal 9 and the pipe segment joint 11, the probability of gas leakage is extremely low and can be ignored under the premise of intact sealing. However, as the shield excavates the slag 34, the screw conveyor slag outlet 14 will be transported out and fall onto the belt 15. The slag 34 will be dispersed, and most of the gas wrapped in the slag 34 will be released and diffused into the nearby air (if the original soil cut by the shield contains gas, the concentration is generally very high. Without considering the improvement of the slag 34 and the addition of air, the gas concentration is generally higher than the gas explosion concentration). Since there are a large number of non-explosion-proof electrical equipment in the shield machine area 17 and the shield trolley area 18, the high-concentration gas released from the screw conveyor slag outlet 14 can easily cause a gas explosion when it encounters a high-temperature fire source such as an ignition of an electrical equipment contactor during the diffusion process. In order to prevent gas explosion, the present invention adds a gas explosion-proof device 16 to the shield machine. During the shield construction process, the use of the gas explosion-proof device 16 ensures that the gas concentration in the shield machine area 17 and the shield trolley area 18 is within a safe range.

[0038] like Figure 1 As shown, the explosion-proof device for gas tunnel earth pressure balance shield construction includes a cutter head 1, an earth chamber 2, a front shield 3, a middle shield 4, a shield tail 7, a conveying mechanism and a gas explosion-proof device 16;

[0039] The cutter head 1 is arranged in front of the soil chamber 2, and the soil chamber 2 is arranged in the front shield 3. The cutter on the cutter head 1 cuts off the slag 34 on the front face, and the slag 34 enters the soil chamber 2.

[0040] The middle shield 4 is between the front shield 3 and the shield tail 7. A propulsion cylinder 5 and / or a segment assembler 8 are arranged in the middle shield 4 and the shield tail 7. A shield tail seal 9 is arranged at the shield tail 7. A hinge seal 6 (device) is adopted at the shell hinge of the middle shield 4 and the shield tail 7. A sealing device is arranged at the segment joint 11.

[0041] The conveying mechanism includes a screw conveyor 12 and a belt 15. The screw conveyor 12 is used to convey the slag 34 in the soil chamber 2. The cutter head 1 rotates, and the thrust cylinder 5 presses against the front end surface of the segment 10 to provide excavation reaction force. The cutter on the cutter head 1 cuts off the slag on the front face and enters the soil chamber 2. The screw shaft of the screw conveyor 12 rotates, and the slag 34 in the soil chamber 2 is conveyed to the screw conveyor slag outlet 14 with the screw conveyor rear gate 13 opened. The slag 34 falls on the belt 15; the running belt 15 transports the slag 34 to the belt 15 slag unloading place, and falls into the slag truck. Then the slag 34 is transported to the shield working shaft with the slag truck and abandoned. After the shield excavates a distance (generally the width of a ring of segments 10), it stops excavating. The segment assembler 8 assembles a ring of segments 10 into a whole ring, and then excavates and assembles again, and the construction is cyclical.

[0042] The main body of the gas explosion-proof device 16 is arranged at the rear of the shield main machine area 17 and the shield trolley area 18; during the shield construction process, the use of the gas explosion-proof device 16 ensures that the gas concentration in the shield main machine area 17 and the shield trolley area 18 is within a safe range.

[0043] The gas explosion-proof device 16 is a device that can prevent explosion accidents in situations containing explosive and dangerous gas (gas) mixtures, such as explosion-proof motors, etc. The present invention has a shield main machine area 17, a shield trolley area 18 and an explosion-proof area 19. In the shield main machine area 17 or the shield trolley area 18, the concentration of a small amount of gas entrained by the slag 34 is diluted by external air to reduce the gas concentration and avoid explosion. The gas explosion-proof device 16 is used to dilute the high-concentration gas released from the slag outlet 14 of the screw conveyor to a safe concentration range and exhaust it to the full explosion-proof equipment area at the rear of the shield trolley through the explosion-proof fan 25, reducing the risk of gas explosion in the shield main machine and the trolley.

[0044] Embodiment 2

[0045] like Figure 2 As shown, the gas explosion-proof device 16 includes an exhaust pipe 26, an explosion-proof fan 25, an air intake channel and a gas sensor; the gas sensor is used to detect the gas concentration, the exhaust pipe 26 is used to exhaust the gas, and the explosion-proof fan 25 provides the power for exhausting the air.

[0046] like Figure 3 As shown, for the air intake channel, an exhaust duct 26 is arranged above the air intake channel, and a thin plate 29 (a plate with a thickness of 2mm-10mm) is arranged below the air intake channel. The thin plate 29 is connected to the belt 15 through a flexible seal, wherein the air intake channel except for the air inlet 24 and the air outlet 21 connected to the exhaust duct 26 is sealed to form a sealed space 22.

[0047] The flexible seal adopts a rubber sealing plate 31, which has good sealing effect, and is wear-resistant and has a long service life. One end of the rubber sealing plate 31 is fixed to the thin plate 29 (it can be bonded), and the other end of the rubber sealing plate 31 should be close to the belt 15 during use. The running belt 15 is sealed with the thin plate 29 and the three surface steel plates of the screw conveyor slag outlet 14 by the rubber sealing plate 31, and the rubber sealing plate 31 is fixed to the thin plate 29 and the three surface steel plates of the screw conveyor slag outlet 14. The screw conveyor slag outlet 14, the belt 15, the thin plate 29, the rubber sealing plate 31, the exhaust port 21, the air inlet 24, and the exhaust pipe 26 constitute a sealed space 22. Except for the exhaust port 21 and the air inlet 24, the rest of the sealed space 22 is isolated from the tunnel.

[0048] A main roller 33 and side rollers 32 are arranged below the belt 15 . The main roller 33 is arranged in the middle, and side rollers 32 are arranged on both sides of the main roller 33 .

[0049] The main roller 33 and the side roller 32 are installed on the support frame 30. In addition, the support frame 30 is also used to support the thin plate 29.

[0050] This embodiment has a detailed arrangement for the air inlet passage, through which the sealed space 22 can be sealed all around, and the gas and other gases can be mixed and transported to avoid excessive gas concentration. The entire sealing structure is quite ingenious and meets the requirements of sealed transportation.

[0051] Embodiment 3

[0052] A gas sensor is installed in each of the sealed space 22 of the slag outlet 14 of the screw conveyor, the rear opening of the sealed space 22, the exhaust duct 26, and the end of the exhaust duct 26, which are the first gas sensor 20, the second gas sensor 23, the third gas sensor 27 and the fourth gas sensor 28.

[0053] An explosion-proof fan 25 is installed on the exhaust pipe 26 , an air suction port 21 is arranged on one side of the explosion-proof fan 25 , and an air outlet is arranged on the other side of the explosion-proof fan 25 .

[0054] The explosion-proof fan 25 is arranged in the shield trolley area 18 , a section of the exhaust pipe 26 connected to the explosion-proof fan 25 is communicated with the sealed space 22 , and an air outlet of another section of the exhaust pipe 26 connected to the explosion-proof fan 25 is arranged in the explosion-proof area 19 .

[0055] The explosion-proof fan 25 adopts a variable frequency explosion-proof fan 25, and the flow rate of the explosion-proof fan 25 per unit time is adjusted by frequency conversion. The electrical equipment within the explosion-proof area 19 (such as lighting, cables, electrical junction boxes, other electrical equipment, etc.) all have explosion-proof functions, and these explosion-proof electrical appliances are all existing, but this scheme selects these explosion-proof electrical appliances in terms of selection.

[0056] The working process of the gas explosion-proof device 16 is as follows: before the shield screw conveyor 12 discharges slag, the explosion-proof fan 25 is turned on, and the explosion-proof fan 25 draws the gas in the sealed space 22 of the screw conveyor slag outlet 14 to the explosion-proof area 19. When the sealed space 22 forms a negative pressure, the air outside the air inlet 24 at the rear of the sealed space 22 enters the sealed space 22. When the screw conveyor 12 discharges slag, the gas released from the slag 34 at the screw conveyor slag outlet 14 and the gas entering the air inlet 24 are discharged to the explosion-proof area 19 through the exhaust pipe 26 by the explosion-proof fan 25, which not only dilutes the gas released from the slag 34 at the screw conveyor slag outlet 14, but also ensures that the released gas does not spread in the shield main machine area 17 and the shield trolley area 18, ensuring that the gas concentration in the shield main machine area 17 and the shield trolley area 18 is within the safe concentration range. When the shield excavation stops and the rear gate 13 of the screw conveyor is closed, the explosion-proof fan 25 can stop running.

[0057] According to the speed of the gas released by the slag 34 at the slag outlet 14 of the screw conveyor, the length of the sealed space 22 can be adjusted to achieve the release of most of the gas and exhaust it by the explosion-proof fan 25.

[0058] According to the actual content of gas in the slag 34, the shield tunneling speed can be adjusted to achieve the purpose of reducing the amount of gas released per unit time.

[0059] According to the gas flow rate per unit time released from the slag 34 in the sealed space 22, the wind flow rate per unit time of the explosion-proof fan 25 can be adjusted to achieve a gas concentration after dilution within the allowable safe gas concentration requirement.

[0060] The shield screw conveyor slag outlet 14, the belt 15 slag receiving port, and a section of the belt 15 near the belt 15 slag receiving port are sealed with a thin plate 29. There is an opening at the rear of the sealed space 22. The upper opening of the sealed space 22 is connected to the exhaust pipe 26. The end of the exhaust pipe 26 is installed with an explosion-proof fan 25. The air outlet of the explosion-proof fan 25 continues to be connected to the exhaust pipe 26. The exhaust pipe 26 extends to the rear of the shield trolley. In the shield main machine area 17, the shield trolley area 18 and the explosion-proof area 19, gas sensors should be installed according to the specifications to detect the gas concentration, and effective ventilation should be carried out to reduce the gas concentration discharged from the explosion-proof device to the explosion-proof area 19 and the gas concentration released from the slag 34 in other parts to prevent gas explosions.

[0061] Embodiment 4

[0062] This embodiment provides an explosion-proof construction method for earth pressure balance shield construction in a gas tunnel. The explosion-proof fan 25 is turned on before the shield screw conveyor 12 discharges slag. The explosion-proof fan 25 draws gas from the sealed space 22 of the screw conveyor slag outlet 14 to the rear of the shield trolley.

[0063] When negative pressure is formed in the sealed space 22, air outside the rear opening of the sealed space 22 enters the sealed space 22;

[0064] When the screw conveyor 12 discharges slag, the gas released from the slag 34 at the slag outlet and the gas entering the rear of the sealed space 22 are sucked away by the explosion-proof fan 25, which not only dilutes the gas released from the slag outlet but also ensures that the released gas does not diffuse in the shield mainframe and the trolley, ensuring that the gas concentration in the shield mainframe and the trolley is within the safe concentration range. Through the detection of gas concentration by four gas sensors, the shield excavation and the exhaust volume of the explosion-proof fan 25 can be adjusted and controlled.

[0065] As attached Figure 2 , Attachment Figure 3 As shown, the control process of the gas explosion-proof device 16 is as follows: the first gas sensor 20-the fourth gas sensor 28 can detect the gas concentration in real time. During the operation of the explosion-proof fan 25, when the gas concentration detected by the third gas sensor 27 and the fourth gas sensor 28 is equal to or exceeds the safe gas concentration allowed in the explosion-proof area 19, the frequency conversion motor of the explosion-proof fan 25 increases the frequency and increases the air flow rate per unit time to the maximum value. If the gas concentration detected by the third gas sensor 27 and the fourth gas sensor 28 continues to increase and reaches the highest safe gas concentration allowed in the explosion-proof area 19, the rear gate 13 of the screw conveyor is automatically closed, and the amount of gas released in the slag 34 at the slag outlet 14 of the screw conveyor is reduced to 0, and then other measures to reduce the gas concentration are taken, such as reducing the shield excavation speed or replacing the explosion-proof fan 25 with a higher air flow rate per unit time. During the operation of the explosion-proof fan 25, when the gas concentration detected by the second gas sensor 23 is equal to or exceeds the gas safety concentration in the shield main engine area 17 and the shield trolley area 18, the frequency conversion motor of the explosion-proof fan 25 increases the frequency and increases the wind flow rate per unit time to the maximum value. If the gas concentration detected by the second gas sensor 23 continues to increase and reaches the maximum safe gas concentration allowed by the shield main engine area 17 and the shield trolley area 18, the rear gate 13 of the screw conveyor is automatically closed, and then other measures to reduce the gas concentration are taken, such as reducing the shield excavation speed, strengthening the ventilation of the shield main engine area 17 and the shield trolley area 18, or replacing the explosion-proof fan 25 with a higher wind flow rate per unit time. Through the detection of the gas concentration of the first gas sensor 20, the gas concentration released by the slag 34 can be intuitively understood. Under normal circumstances (just as an example), the set gas concentration values ​​are: the maximum safe gas concentration allowed in explosion-proof area 19 > the safe gas concentration allowed in explosion-proof area 19 > the maximum safe gas concentration allowed in shield main machine area 17 and shield trolley area 18 > the safe gas concentration in shield main machine area 17 and shield trolley area 18. The maximum safe gas concentration allowed in shield main machine area 17 and shield trolley area 18 should not exceed 0.5%.

[0066] The present invention provides a gas dilution and extraction device and monitoring control system for the slag outlet 14 of the earth pressure balance shield screw conveyor. The low-concentration gas gas mixed with the high-concentration gas gas overflowing from the slag outlet 14 of the earth pressure balance shield screw conveyor and the outside air is discharged to the rear of the shield machine trolley (all equipment at this position adopts explosion-proof equipment) through a closed pipeline by the explosion-proof fan 25, and then discharged from the tunnel through normal tunnel exhaust. This device can ensure that the gas concentration in the shield main machine and trolley without explosion-proof capability is always lower than the required value to prevent gas explosion.

[0067] The present invention is applicable to low-gas, high-gas and gas-outburst tunnels, as well as coal mining tunnel construction and coal mining operations. According to the gas content per ton of coal in the excavation face, the purpose of diluting the gas to a safe allowable concentration is achieved by increasing the wind flow of the explosion-proof fan 25 units per time and reducing the shield tunneling speed.

[0068] Since the method described in this embodiment is the method used to implement the first to third embodiments of the present invention, the method described in the embodiment of the present invention can be understood by those skilled in the art for the specific implementation and various variations of the method of the embodiment, so how to implement the above embodiments is not described in detail here. As long as those skilled in the art implement the method in the embodiment of the present invention, it belongs to the protection scope of the present invention.

[0069] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The explosion-proof device for gas tunnel earth pressure balance shield construction is characterized by: It includes cutter head, soil chamber, front shield, middle shield, shield tail, conveying mechanism and gas explosion-proof device; The cutterhead is set in front of the soil cabin, and the soil cabin is set in the front shield. The cutters on the cutterhead cut off the debris on the front tunnel face, and the debris enters the soil cabin; The middle shield is between the front shield and the tail shield. A propulsion cylinder and / or a segment assembler are arranged in the middle shield and the tail shield. A tail shield seal is arranged at the tail shield. A hinged seal is adopted at the shell hinge of the middle shield and the tail shield. A sealing device is arranged at the segment joint. The conveying mechanism includes a screw conveyor and a belt. The screw conveyor is used to convey the slag in the soil compartment. The screw shaft of the screw conveyor rotates to convey the slag in the soil compartment to the slag outlet of the screw conveyor whose rear gate has been opened, and the slag falls onto the belt. The main body of the gas explosion-proof device is set at the rear of the shield machine and the trolley area; during the shield construction process, the use of the gas explosion-proof device ensures that the gas concentration in the shield machine area and the shield trolley area is within a safe range; The gas explosion-proof device includes an exhaust pipe, an explosion-proof fan, an air intake channel and a gas sensor; The gas sensor is used to detect the gas concentration, the exhaust pipe is used to exhaust the gas, and the explosion-proof fan provides the power for exhaust; An exhaust pipe is arranged above the air intake channel, and a thin plate is arranged below the air intake channel. The thin plate is connected to the belt through a flexible seal. Except for the air inlet and the air outlet connected to the exhaust pipe, the rest of the air intake channel is sealed to form a sealed space. When negative pressure is formed in the sealed space, air outside the rear opening of the sealed space enters the sealed space; An explosion-proof fan is installed on the exhaust duct, an air inlet is arranged on one side of the explosion-proof fan, and an air outlet is arranged on the other side of the explosion-proof fan; the explosion-proof fan is arranged in the shield trolley area, a section of the exhaust duct connected to the explosion-proof fan is connected to the sealed space, and the air outlet of the other section of the exhaust duct connected to the explosion-proof fan is arranged in the explosion-proof area; When the screw conveyor is discharging slag, the gas released from the slag at the slag outlet and the gas entering from the rear of the sealed space are sucked away by the explosion-proof fan, which not only dilutes the gas released from the slag outlet but also ensures that the released gas does not spread in the shield main machine and the trolley, ensuring that the gas concentration in the shield main machine and the trolley is within the safe concentration range.

2. The explosion-proof device for gas tunnel earth pressure balance shield construction according to claim 1 is characterized by: The flexible seal adopts a rubber sealing plate, which has good sealing effect, wear resistance and long service life.

3. The explosion-proof device for gas tunnel earth pressure balance shield construction according to claim 2 is characterized by: A main roller and side rollers are arranged below the belt, the main roller is arranged in the middle, and side rollers are arranged on both sides of the main roller.

4. The explosion-proof device for gas tunnel earth pressure balance shield construction according to claim 3 is characterized by: The main roller and the side rollers are mounted on the support frame, and the support frame is also used to support the thin plate.

5. The explosion-proof device for gas tunnel earth pressure balance shield construction according to any one of claims 2 to 4, characterized in that: A gas sensor is installed in the sealed space of the slag outlet of the screw conveyor, at the rear opening of the sealed space, in the exhaust duct, and at the end of the exhaust duct.

6. The construction method of explosion-proof device for gas tunnel earth pressure balance shield construction according to claim 1, characterized in that: Before the shield screw conveyor discharges slag, the explosion-proof fan is turned on to draw the gas in the sealed space of the screw conveyor discharge port to the rear of the shield trolley; When negative pressure is formed in the sealed space, air outside the rear opening of the sealed space enters the sealed space; When the screw conveyor discharges slag, the gas released from the slag at the slag outlet and the gas entering from the rear of the sealed space are sucked away by the explosion-proof fan, which not only dilutes the gas released from the slag outlet but also ensures that the released gas does not diffuse in the shield mainframe and the trolley, ensuring that the gas concentration in the shield mainframe and the trolley is within the safe concentration range; The first gas sensor to the fourth gas sensor can detect the gas concentration in real time; during the operation of the explosion-proof fan, when the gas concentration detected by the third gas sensor and the fourth gas sensor is equal to or exceeds the safe gas concentration allowed in the explosion-proof area, the explosion-proof fan variable frequency motor increases the frequency and increases the wind flow per unit time to the maximum value; if the gas concentration detected by the third gas sensor and the fourth gas sensor continues to increase and reaches the highest safe gas concentration allowed in the explosion-proof area, the rear gate of the screw conveyor is automatically closed to reduce the amount of gas released in the slag at the slag outlet of the screw conveyor to 0, and then take measures to reduce the shield tunneling speed or replace the explosion-proof fan with a higher wind flow per unit time; During the operation of the explosion-proof fan, when the gas concentration detected by the second gas sensor is equal to or exceeds the safe gas concentration in the shield main machine area and the shield trolley area, the explosion-proof fan variable frequency motor increases the frequency and increases the air flow per unit time to the maximum value; If the gas concentration detected by the second gas sensor continues to increase and reaches the maximum safe gas concentration allowed in the shield main machine area and the shield trolley area, the rear gate of the screw conveyor will automatically close, and then measures such as reducing the shield excavation speed, strengthening the ventilation of the shield main machine area and the shield trolley area, or replacing the explosion-proof fan with a higher air flow per unit time will be taken; through the detection of the gas concentration by the first gas sensor, the gas concentration released by the slag can be intuitively understood; the set gas concentration value: the maximum safe gas concentration allowed in the explosion-proof area > the safe gas concentration allowed in the explosion-proof area > the maximum safe gas concentration allowed in the shield main machine area and the shield trolley area > the gas safety concentration in the shield main machine area and the shield trolley area, the maximum safe gas concentration allowed in the shield main machine area and the shield trolley area should not exceed 0.5%.

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