Negative Pressure Air-seal Induced System for Controlling Environment of Pipe Jacking Operation

Abstract

Provided is a negative pressure air-seal induced system for controlling the environment of pipe jacking operation, including a turbulent airflow supply device provided at a certain distance from a tunnelling head and located in a tool pipe, wherein the turbulent airflow supply device forms an air curtain sealing structure at a certain angle with respect to the tunnelling head, the airflow rebounds and swirls between the air curtain and the tunnelling head to form an air turbulence vortex, so that the toxic and harmful gases are fully stirred and mixed to form a steady ascending airflow; and an exhaust device provided in the tool pipe, wherein a first air vent of the exhaust device is located between the tunnelling head and the turbulent airflow supply device to collect and receive the toxic and harmful gases, and a second air vent is located above ground to discharge the toxic and harmful gases off-site.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of pipe jacking construction technology, particularly relates to a negative pressure air-seal induced system for controlling the environment of pipe jacking operation.BACKGROUND

[0002] Underground pipe jacking construction generally needs to pass through silt stratification, coal seam and so on, which may contain abundant toxic and harmful gases such as carbonic oxide, hydrogen sulfide and methane nitrous-oxides. In extreme cases, a tunnelling head may even drill into a natural gas pipeline or an industrial pipeline, and other kinds of toxic and harmful gases may flood into the front-end tunnelling head through a tunnel face, and then enter a jacking pipeline through a tool pipe. The aggregated harmful gases will endanger the health of construction workers and even cause explosion accidents. In addition, excessive jacking distance will also lead to hypoxia and suffocation of workers in the pipeline, leading to great safety hazards.

[0003] For these reasons, the pipe jacking construction workers must use ventilation devices to effectively ensure safe working environment in the jacking pipe. However, the composition of toxic and harmful gases in the pipe jacking operation environment is unknown, and the components contained in the air may be quite different in relative molecular mass. For example, as methane has a relative molecular mass of 16.04, which is much less than that of air (29), it is suspended at the top of the jacking pipe at static state; while nitrogen dioxide has a relative molecular mass of 56.01, which is much greater than that of air, so it deposits to the bottom of the jacking pipe at static state. Therefore, the exhaust of harmful gases must consider the differences in composition and molecular mass. As a result, it is difficult to control the internal working environment of jacking pipe, and the control effect is often unsatisfactory. However, there is no environmental control requirement or effective control measure stipulated in existing national or industrial codes and standards (e.g., the Code for Construction and Acceptance of Water and Sewerage Pipeline Works (GB50268-2008) and the Standard for Safety Inspection of Municipal Engineering Construction (CJJ / T 275-2018)).

[0004] At present, the main approaches to controlling the pipe jacking operation environment in the industry are as follows:

[0005] 1. An air-supply mechanical ventilation. That is, a fan or an air compressor is provided on the ground or in a working shaft, an air duct or a compressed air hose is laid along an overall jacking pipeline to send the external fresh air directly to the vicinity of a tunnel face. In this process, the airflow throughout the jacking pipeline is in a positive pressure state. With this ventilation approach, the toxic and harmful gases are easily dispersed in the jacking pipeline and even enter the working shaft. Also, with this approach, the toxic and harmful gases are dispersed in large range and easy to produce a secondary air that forms a windless zone and a vortex zone in some areas, which are not conducive to effective discharge of the toxic and harmful gases from the pipeline. In addition, it is necessary to stop air supply and install additional air ducts during the hoisting of new pipe segments, so the continuous ventilation and efficiency of pipe jacking are affected.

[0006] 2. An air-exhaust mechanical ventilation. That is, an air outlet is provided in the vicinity of a front-end tunnelling head and a tunnel face of a jacking pipe, so that the toxic and harmful gases are induced and discharged out of the pipe jacking system by use of a fan. In this process, the airflow throughout the jacking pipeline is in a negative pressure state, and the fresh air is replenished into the jacking pipe through a working shaft. With the ventilation approach, due to the small area affected by the confluence action of the discharged air, it is difficult to effectively discharge the toxic and harmful gases if they escape from the air confluence area, resulting in gas accumulation in the windless zone or the vortex zone of the secondary air.

[0007] 3. A combined air-supply and air-exhaust mechanical ventilation. That is, firstly, the fresh air is delivered directly to the front section of a jacking pipe by use of a fan or an air compressor, and then an exhaust fan is used to discharge the air near a tunnel face, and finally a mechanical suction circulating ventilation is formed. With the ventilation approach, two pipes need to be laid in the narrow jacking pipe, which occupy the operating space area of pipe jacking and interfere with the construction. Also, the workload of pipeline connection and maintenance increases accordingly.

[0008] The above three ventilation approaches are all belong to general ventilation, and may have a risk that in the pipe jacking where the toxic and harmful gases are only produced at the tunnel face, such gases escape in a large range and even into the working shaft. In addition, with the above three ventilation approaches, the air distribution is poorly controlled, so it is difficult to effectively exhaust the toxic and harmful gases with complex components and considerable differences in molecular weight that may be produced in the pipe jacking construction.SUMMARY

[0009] The present invention is intended to solve at least one of the technical problems in the prior art.

[0010] Therefore, the present invention provides a negative pressure air-seal induced system for controlling the environment of pipe jacking operation.

[0011] The present invention provides a negative pressure air-seal induced system for controlling the environment of pipe jacking operation, which include:

[0012] a turbulent airflow supply device provided at a certain distance from a tunnelling head and located in a tool pipe, wherein the turbulent airflow supply device forms anair curtain sealing structure at a certain angle with respect to the tunnelling head, the airflow rebounds and swirls between the air curtain and the tunnelling head to form an air turbulence vortex, so that the toxic and harmful gases are fully stirred and mixed to form a steady ascending airflow;

[0013] and an exhaust device provided in the tool pipe, wherein a first air vent of the exhaust device is located between the tunnelling head and the turbulent airflow supply device to collect and receive the toxic and harmful gases, and a second air vent is located above ground to discharge the toxic and harmful gases off-site.

[0014] The negative pressure air-seal induced system for controlling the environment of pipe jacking operation as provided by the present invention includes the turbulent airflow supply device and the exhaust device. Wherein the turbulent airflow supply device is used to form the air-seal structure of the air curtain, which is used to effectively restrain the toxic and harmful gases invading the tool pipe through the front-end tunnelling head in the area, thus preventing the toxic and harmful gases from further escape. Wherein regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of the tool pipe, where the jet is at a distance of not less than 1 meter from the tunnelling head, thus facilitating the airflow in rebounding and swirling (if possible, computational fluid dynamics (CFD) simulation with the jet angle and an average flow velocity of the air curtain is carried out to accurately determine the jet angle and the average flow velocity according to the simulation results). In addition, the average flow velocities at different jet angles are not less than 0.5 m / s to ensure the tightness of the air seal. By controlling the jet angle and the average flow velocity, an air turbulence vortex is formed in the whole space of the tool pipe, so that various toxic and harmful gases with different relative molecular masses are fully stirred and mixed to form a steady ascending airflow, thus lessening the difficulty of collecting the toxic and harmful gases. On the basis of the above, the present technical solution adds the exhaust device. After the air curtain forms a steady ascending airflow, the first air vent disposed at the top continues the discharge to achieve a replacement effect, thus improving the exhaust ventilation efficiency of the toxic and harmful gases. In addition, the negative pressure between the air curtain and the tunnelling head is higher than that in other areas of the pipe jacking system, further preventing the toxic and harmful gases from overflowing and optimizing the operation environment of an overall jacking pipeline, so as to achieve the objects of hierarchical increment of the negative pressure, replacement and supplement of the fresh air, hierarchical concentration-based control of the toxic and harmful gases and optimization of the ventilation efficiency.

[0015] According to the above technical solution of the present invention, the negative pressure air-seal induced system for controlling the environment of pipe jacking operation may also have the following additional technical features:

[0016] In the above technical solution, the exhaust device also includes:

[0017] an exhaust fan provided in the tool pipe;

[0018] a first air duct communicated with the exhaust fan, wherein the first air duct is located in the tool pipe, and the first air vent is a port of the first air duct;

[0019] a second air duct communicated with the exhaust fan, wherein the second air duct is at least located in a jacking pipe;

[0020] a third air duct communicated with the second air duct and having an air outlet located above ground to form the second air vent;

[0021] wherein the first air duct, the second air duct and the third air duct form an exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head are discharged on the ground.

[0022] In the present technical solution, the first air duct, the second air duct and the third air duct form an exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head are discharged on the ground. The first air duct is in a rigid structure, and the first air vent is disposed at the top within 5 meters from the tunnelling head, and the exhaust fan is set relative to the average flow velocity of not less than 1 m / s in the jacking pipe. The second air duct is in a flexible structure, with one end connected with the exhaust fan and the other end detachably connected with the third air duct, and the second air duct is located in the tool pipe. In this way, the air curtain is integrally disposed in the tool pipe, thus reducing the pipeline structure and works (e.g., any pipeline connection) after jacking under the ground. The exhaust fan is disposed between the air curtain and the tunnelling head, and a standardized flexible duct segment is provided between the exhaust fan and a reaction wall, namely, the second duct (e.g., an air distribution duct). In the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with another standardized flexible duct segment after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segment is gradually opened, during which the air discharge to the outdoor ground by the system is not affected, so as to achieve the object of improving the pipe jacking efficiency without influence or interruption of the pipe jacking process.

[0023] In the above technical solution, the second air duct includes a plurality of flexible short pipes detachably interconnected, and the flexible short pipes are increased corresponding to newly hoisted pipe segments.

[0024] In the present technical solution, the second air duct is composed of flexible short pipes, namely, standardized flexible air duct segments. As mentioned above, in the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with newly added standardized flexible duct segments after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segments are gradually opened, during which the air discharge to the ground outdoor by the system is not affected, so as to achieve the object of improving the pipe jacking efficiency without influence or interruption of the pipe jacking process.

[0025] In the above technical solution, the flexible short pipes realize the detachable interconnection by use of pipe joints; or the flexible short pipes realize the detachable interconnection by use of a zipper structure.

[0026] In the present technical solution, all of the flexible short pipes, namely, all of the standardized flexible air duct segments, may be interconnected in the form of pipe joint connection or zipper structure to ensure the above connection process.

[0027] In the above technical solution, regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of a tool pipe, where the jet is at a distance of not less than 1 meter from the tunnelling head, thus facilitating the airflow in rebounding and swirling.

[0028] In the present technical solution, as mentioned above, the rebound and swirl of the airflow is ensured by use of the above arrangement.

[0029] In the above technical solution, average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s.

[0030] In the present technical solution, as mentioned above, the average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s to ensure the tightness of the air seal by the air curtain. It is a matter of course that the velocity may be adjusted and optimized according to actual working conditions.

[0031] In the above technical solution, an average flow velocity of the exhaust device is not less than 1 m / s, and the first air vent is disposed at the top within 5 meters from the tunnelling head.

[0032] In the present technical solution, in order to guarantee the replacement effect, the velocity of the exhaust device and the location of the first air vent are specified. Again, the above parameters may be optimized and adjusted according to actual working conditions.

[0033] In the above technical solution, more than 50% air supply at the tunnelling head is supplemented by the air curtain, and the negative pressure in the area between the air curtain and the tunnelling head is higher than that in other areas of a pipe jacking system.

[0034] In the present technical solution, as mentioned above, by increasing the negative pressure value of the area where the toxic and harmful gases disperse, the toxic and harmful gases are further prevented from overflowing, thus optimizing the operation environment of an overall jacking pipeline.

[0035] As can be appreciated that the negative pressure air-seal induced system for controlling the environment of pipe jacking operation provided by the present invention has the following beneficial effects:

[0036] The toxic and harmful gases are sealed between the air curtain and the tunnelling head to prevent large-range escape; by use of the resulting steady ascending airflow, the toxic and harmful gases with complex components and large difference in relative molecular mass are efficiently exhausted at a time, so that a wide adaptability is achieved; through design of the angle and the velocity of the air curtain, the exhaust ventilation efficiency of the toxic and harmful gases is improved depending on the replacement effect formed by continuous discharge with the exhaust system; by increasing the negative pressure value of the area where the toxic and harmful gases disperse, the toxic and harmful gases are further prevented from overflowing, thus optimizing the operation environment of an overall jacking pipeline; and the pipe jacking efficiency is improved without influence or interruption of the pipe jacking process.

[0037] The additional aspects and advantages of the present invention would become clear from the description below or would be understood through the practice of the present invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The additional aspects and advantages mentioned above and / or attached would be clear and easy to understand from the following description of embodiments in conjunction with the accompanying drawings, wherein:

[0039] FIG. 1 is a schematic diagram of the negative pressure air-seal induced system for controlling the environment of pipe jacking operation of the present invention;

[0040] FIG. 2 is a side cross-sectional view of the negative pressure air-seal induced system for controlling the environment of pipe jacking operation of the present invention.

[0041] Wherein, the corresponding relationship between reference numerals and component names in FIGS. 1 and 2 is as follows:

[0042] 1—turbulent airflow supply device, 2—exhaust device, 201—first air vent, 202—second air vent, 203—exhaust fan, 204—first air duct, 205—second air duct, 206—third air duct, 3—tunnelling head, 4—tool pipe.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] The present invention will be further described in detail in combination with accompanied drawings and embodiments for clear understanding of the above objects, features and advantages of the present invention. It should be noted that the features in the embodiments and the embodiments of the present application can be combined with each other in a non-conflicting situation.

[0044] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can also be implemented in other ways different from those described here, so the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0045] Referring to FIGS. 1 and 2, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation provided according to some embodiments of the present invention is described below.

[0046] According to some embodiments of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided.

[0047] As shown in FIGS. 1 and 2, according to the first embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, which includes:

[0048] a turbulent airflow supply device 1 provided at a certain distance from a tunnelling head 3 and located in a tool pipe 4, wherein the turbulent airflow supply device 1 forms anair curtain sealing structure at a certain angle with respect to the tunnelling head 3, the airflow rebounds and swirls between the air curtain and the tunnelling head 3 to form an air turbulence vortex, so that the toxic and harmful gases are fully stirred and mixed to form a steady ascending airflow;

[0049] and an exhaust device 2 provided in the tool pipe 4, wherein a first air vent 201 of the exhaust device 2 is located between the tunnelling head 3 and the turbulent airflow supply device 1 to collect and receive the toxic and harmful gases, and a second air vent 202 is located above ground to discharge the toxic and harmful gases off-site.

[0050] The negative pressure air-seal induced system for controlling the environment of pipe jacking operation provided by the present invention includes the turbulent airflow supply device 1 and the exhaust device 2. Wherein the turbulent airflow supply device 1 is used to form the air-seal structure of the air curtain, which is used to effectively restrain the toxic and harmful gases invading the tool pipe 4 through the front-end tunnelling head 3 in the area, thus preventing the toxic and harmful gases from further escape. Wherein regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of the tool pipe 4, where the jet is at a distance of not less than 1 meter from the tunnelling head 3, thus facilitating the airflow in rebounding and swirling (if possible, CFD simulation with the jet angle and an average flow velocity of the air curtain is carried out to accurately determine the jet angle and the average flow velocity according to the simulation results). In addition, the average flow velocities at different jet angles are not less than 0.5 m / s to ensure the tightness of the air seal. By controlling the jet angle and the average flow velocity, an air turbulence vortex is formed in the whole space of the tool pipe 4, so that various toxic and harmful gases with different relative molecular masses are fully stirred and mixed to form a steady ascending airflow, thus lessening the difficulty of collecting the toxic and harmful gases. On such basis, the present technical solution adds the exhaust device 2. After the air curtain forms a steady ascending airflow, the first air vent 201 disposed at the top continues the discharge to achieve a replacement effect, thus improving the exhaust ventilation efficiency of the toxic and harmful gases. In addition, the negative pressure between the air curtain and the tunnelling head 3 is higher than that in other areas of the pipe jacking system, further preventing the toxic and harmful gases from overflowing and optimizing the operation environment of an overall jacking pipeline, so as to achieve the objects of hierarchical increment of the negative pressure, replacement and supplement of the fresh air, hierarchical concentration-based control of the toxic and harmful gases and optimization of the ventilation efficiency.

[0051] According to the second embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, wherein, on the basis of the first embodiment, the exhaust device 2 further includes:

[0052] an exhaust fan 203 provided in the tool pipe 4;

[0053] a first air duct 204 communicated with the exhaust fan 203, wherein the first air duct 204 is located in the tool pipe 4, and the first air vent 201 is a port of the first air duct 204;

[0054] a second air duct 205 communicated with the exhaust fan 203, wherein the second air duct 205 is at least located in a jacking pipe;

[0055] a third air duct 206 communicated with the second air duct 205 and having an air outlet located above ground to form the second air vent 202;

[0056] wherein the first air duct 204, the second air duct 205 and the third air duct 206 form an exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head 3 are discharged on the ground.

[0057] In the present embodiment, the first air duct 204, the second air duct 205 and the third air duct 206 form the exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head 3 are discharged on the ground. The first air duct 204 is in a rigid structure, and the first air vent 201 is disposed at the top within 5 meters from the tunnelling head 3, and the exhaust fan 203 is set relative to the average flow velocity of not less than 1 m / s in the jacking pipe. The second air duct 205 is in a flexible structure, with one end connected with the exhaust fan 203 and the other end detachably connected with the third air duct 206, and the second air duct 205 is located in the tool pipe 4. In this way, the air curtain is integrally disposed in the tool pipe 4, thus reducing the pipeline structure and works (e.g., any pipeline connection) after jacking under the ground. The exhaust fan 203 is disposed between the air curtain and the tunnelling head 3, and a standardized flexible duct segment is provided between the exhaust fan 203 and a reaction wall, namely, the second duct 205 (e.g., an air distribution duct). In the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with another standardized flexible duct segment after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segment is gradually opened, during which the air discharge to the outdoor ground by the system is not affected, so as to achieve the object of improving the pipe jacking efficiency without influence or interruption of the pipe jacking process.

[0058] According to the third embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, the second air duct 205 includes a plurality of flexible short pipes detachably interconnected, and the flexible short pipes are increased corresponding to newly hoisted pipe segments.

[0059] In the present embodiment, the second air duct 205 is composed of flexible short pipes, namely, standardized flexible air duct segments. As mentioned above, in the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with newly added standardized flexible duct segments after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segments are gradually opened, during which the air discharge on the ground outdoor by the system is not affected, so as to achieve the object of improving the pipe jacking efficiency without influence or interruption of the pipe jacking process.

[0060] According to the fourth embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, the flexible short pipes realize the detachable interconnection by use of pipe joints; or the flexible short pipes realize the detachable interconnection by use of a zipper structure.

[0061] In the present embodiment, all of the flexible short pipes, namely, all of the standardized flexible air duct segments, may be interconnected in the form of pipe joint connection or zipper structure to ensure the above connection process.

[0062] According to the fifth embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of the tool pipe 4, where the jet is at a distance of not less than 1 meter from the tunnelling head 3, thus facilitating the airflow in rebounding and swirling.

[0063] In the present embodiment, as mentioned above, the rebound and swirl of the airflow is ensured by use of the above arrangement.

[0064] According to the sixth embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s.

[0065] In the present embodiment, as mentioned above, the average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s to ensure the tightness of the air seal by the air curtain. It is a matter of course that the velocity may be adjusted and optimized according to actual working conditions.

[0066] According to the seventh embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, an average flow velocity of the exhaust device 2 is not less than 1 m / s, and the first air vent 201 is disposed at the top within 5 meters from the tunnelling head 3.

[0067] In the present embodiment, in order to guarantee the replacement effect, the velocity of the exhaust device 2 and the location of the first air vent 201 are specified. Again, the above parameters may be optimized and adjusted according to actual working conditions.

[0068] According to the eighth embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, more than 50% air supply at the tunnelling head 3 is supplemented by the air curtain, and the negative pressure in the area between the air curtain and the tunnelling head 3 is higher than that in other areas of a pipe jacking system.

[0069] In the present embodiment, as mentioned above, by increasing the negative pressure value of the area where the toxic and harmful gases disperse, the toxic and harmful gases are further prevented from overflowing, thus optimizing the operation environment of an overall jacking pipeline.

[0070] In the description, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be appropriately combined in any one or more embodiments or examples.

[0071] Any modification, equivalent replacement and improvement made within the spirit and rule of the present invention shall be incorporated in the protection scope of the present invention.

Examples

first embodiment

[0047]As shown in FIGS. 1 and 2, according to the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, which includes:[0048]a turbulent airflow supply device 1 provided at a certain distance from a tunnelling head 3 and located in a tool pipe 4, wherein the turbulent airflow supply device 1 forms anair curtain sealing structure at a certain angle with respect to the tunnelling head 3, the airflow rebounds and swirls between the air curtain and the tunnelling head 3 to form an air turbulence vortex, so that the toxic and harmful gases are fully stirred and mixed to form a steady ascending airflow;[0049]and an exhaust device 2 provided in the tool pipe 4, wherein a first air vent 201 of the exhaust device 2 is located between the tunnelling head 3 and the turbulent airflow supply device 1 to collect and receive the toxic and harmful gases, and a second air vent 202 is located above ground to discharge the...

third embodiment

[0058]According to the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, the second air duct 205 includes a plurality of flexible short pipes detachably interconnected, and the flexible short pipes are increased corresponding to newly hoisted pipe segments.

[0059]In the present embodiment, the second air duct 205 is composed of flexible short pipes, namely, standardized flexible air duct segments. As mentioned above, in the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with newly added standardized flexible duct segments after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segments are gradu...

fourth embodiment

[0060]According to the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, the flexible short pipes realize the detachable interconnection by use of pipe joints; or the flexible short pipes realize the detachable interconnection by use of a zipper structure.

[0061]In the present embodiment, all of the flexible short pipes, namely, all of the standardized flexible air duct segments, may be interconnected in the form of pipe joint connection or zipper structure to ensure the above connection process.

TECHNICAL FIELD

[0001] The present invention relates to the field of pipe jacking construction technology, particularly relates to a negative pressure air-seal induced system for controlling the environment of pipe jacking operation.BACKGROUND

[0002] Underground pipe jacking construction generally needs to pass through silt stratification, coal seam and so on, which may contain abundant toxic and harmful gases such as carbonic oxide, hydrogen sulfide and methane nitrous-oxides. In extreme cases, a tunnelling head may even drill into a natural gas pipeline or an industrial pipeline, and other kinds of toxic and harmful gases may flood into the front-end tunnelling head through a tunnel face, and then enter a jacking pipeline through a tool pipe. The aggregated harmful gases will endanger the health of construction workers and even cause explosion accidents. In addition, excessive jacking distance will also lead to hypoxia and suffocation of workers in the pipeline, leading to great safety hazards.

[0003] For these reasons, the pipe jacking construction workers must use ventilation devices to effectively ensure safe working environment in the jacking pipe. However, the composition of toxic and harmful gases in the pipe jacking operation environment is unknown, and the components contained in the air may be quite different in relative molecular mass. For example, as methane has a relative molecular mass of 16.04, which is much less than that of air (29), it is suspended at the top of the jacking pipe at static state; while nitrogen dioxide has a relative molecular mass of 56.01, which is much greater than that of air, so it deposits to the bottom of the jacking pipe at static state. Therefore, the exhaust of harmful gases must consider the differences in composition and molecular mass. As a result, it is difficult to control the internal working environment of jacking pipe, and the control effect is often unsatisfactory. However, there is no environmental control requirement or effective control measure stipulated in existing national or industrial codes and standards (e.g., the Code for Construction and Acceptance of Water and Sewerage Pipeline Works (GB50268-2008) and the Standard for Safety Inspection of Municipal Engineering Construction (CJJ / T 275-2018)).

[0004] At present, the main approaches to controlling the pipe jacking operation environment in the industry are as follows:

[0005] 1. An air-supply mechanical ventilation. That is, a fan or an air compressor is provided on the ground or in a working shaft, an air duct or a compressed air hose is laid along an overall jacking pipeline to send the external fresh air directly to the vicinity of a tunnel face. In this process, the airflow throughout the jacking pipeline is in a positive pressure state. With this ventilation approach, the toxic and harmful gases are easily dispersed in the jacking pipeline and even enter the working shaft. Also, with this approach, the toxic and harmful gases are dispersed in large range and easy to produce a secondary air that forms a windless zone and a vortex zone in some areas, which are not conducive to effective discharge of the toxic and harmful gases from the pipeline. In addition, it is necessary to stop air supply and install additional air ducts during the hoisting of new pipe segments, so the continuous ventilation and efficiency of pipe jacking are affected.

[0006] 2. An air-exhaust mechanical ventilation. That is, an air outlet is provided in the vicinity of a front-end tunnelling head and a tunnel face of a jacking pipe, so that the toxic and harmful gases are induced and discharged out of the pipe jacking system by use of a fan. In this process, the airflow throughout the jacking pipeline is in a negative pressure state, and the fresh air is replenished into the jacking pipe through a working shaft. With the ventilation approach, due to the small area affected by the confluence action of the discharged air, it is difficult to effectively discharge the toxic and harmful gases if they escape from the air confluence area, resulting in gas accumulation in the windless zone or the vortex zone of the secondary air.

[0007] 3. A combined air-supply and air-exhaust mechanical ventilation. That is, firstly, the fresh air is delivered directly to the front section of a jacking pipe by use of a fan or an air compressor, and then an exhaust fan is used to discharge the air near a tunnel face, and finally a mechanical suction circulating ventilation is formed. With the ventilation approach, two pipes need to be laid in the narrow jacking pipe, which occupy the operating space area of pipe jacking and interfere with the construction. Also, the workload of pipeline connection and maintenance increases accordingly.

[0008] The above three ventilation approaches are all belong to general ventilation, and may have a risk that in the pipe jacking where the toxic and harmful gases are only produced at the tunnel face, such gases escape in a large range and even into the working shaft. In addition, with the above three ventilation approaches, the air distribution is poorly controlled, so it is difficult to effectively exhaust the toxic and harmful gases with complex components and considerable differences in molecular weight that may be produced in the pipe jacking construction.SUMMARY

[0009] The present invention is intended to solve at least one of the technical problems in the prior art.

[0010] Therefore, the present invention provides a negative pressure air-seal induced system for controlling the environment of pipe jacking operation.

[0011] The present invention provides a negative pressure air-seal induced system for controlling the environment of pipe jacking operation, which include:

[0012] a turbulent airflow supply device provided at a certain distance from a tunnelling head and located in a tool pipe, wherein the turbulent airflow supply device forms anair curtain sealing structure at a certain angle with respect to the tunnelling head, the airflow rebounds and swirls between the air curtain and the tunnelling head to form an air turbulence vortex, so that the toxic and harmful gases are fully stirred and mixed to form a steady ascending airflow;

[0013] and an exhaust device provided in the tool pipe, wherein a first air vent of the exhaust device is located between the tunnelling head and the turbulent airflow supply device to collect and receive the toxic and harmful gases, and a second air vent is located above ground to discharge the toxic and harmful gases off-site.

[0014] The negative pressure air-seal induced system for controlling the environment of pipe jacking operation as provided by the present invention includes the turbulent airflow supply device and the exhaust device. Wherein the turbulent airflow supply device is used to form the air-seal structure of the air curtain, which is used to effectively restrain the toxic and harmful gases invading the tool pipe through the front-end tunnelling head in the area, thus preventing the toxic and harmful gases from further escape. Wherein regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of the tool pipe, where the jet is at a distance of not less than 1 meter from the tunnelling head, thus facilitating the airflow in rebounding and swirling (if possible, computational fluid dynamics (CFD) simulation with the jet angle and an average flow velocity of the air curtain is carried out to accurately determine the jet angle and the average flow velocity according to the simulation results). In addition, the average flow velocities at different jet angles are not less than 0.5 m / s to ensure the tightness of the air seal. By controlling the jet angle and the average flow velocity, an air turbulence vortex is formed in the whole space of the tool pipe, so that various toxic and harmful gases with different relative molecular masses are fully stirred and mixed to form a steady ascending airflow, thus lessening the difficulty of collecting the toxic and harmful gases. On the basis of the above, the present technical solution adds the exhaust device. After the air curtain forms a steady ascending airflow, the first air vent disposed at the top continues the discharge to achieve a replacement effect, thus improving the exhaust ventilation efficiency of the toxic and harmful gases. In addition, the negative pressure between the air curtain and the tunnelling head is higher than that in other areas of the pipe jacking system, further preventing the toxic and harmful gases from overflowing and optimizing the operation environment of an overall jacking pipeline, so as to achieve the objects of hierarchical increment of the negative pressure, replacement and supplement of the fresh air, hierarchical concentration-based control of the toxic and harmful gases and optimization of the ventilation efficiency.

[0015] According to the above technical solution of the present invention, the negative pressure air-seal induced system for controlling the environment of pipe jacking operation may also have the following additional technical features:

[0016] In the above technical solution, the exhaust device also includes:

[0017] an exhaust fan provided in the tool pipe;

[0018] a first air duct communicated with the exhaust fan, wherein the first air duct is located in the tool pipe, and the first air vent is a port of the first air duct;

[0019] a second air duct communicated with the exhaust fan, wherein the second air duct is at least located in a jacking pipe;

[0020] a third air duct communicated with the second air duct and having an air outlet located above ground to form the second air vent;

[0021] wherein the first air duct, the second air duct and the third air duct form an exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head are discharged on the ground.

[0022] In the present technical solution, the first air duct, the second air duct and the third air duct form an exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head are discharged on the ground. The first air duct is in a rigid structure, and the first air vent is disposed at the top within 5 meters from the tunnelling head, and the exhaust fan is set relative to the average flow velocity of not less than 1 m / s in the jacking pipe. The second air duct is in a flexible structure, with one end connected with the exhaust fan and the other end detachably connected with the third air duct, and the second air duct is located in the tool pipe. In this way, the air curtain is integrally disposed in the tool pipe, thus reducing the pipeline structure and works (e.g., any pipeline connection) after jacking under the ground. The exhaust fan is disposed between the air curtain and the tunnelling head, and a standardized flexible duct segment is provided between the exhaust fan and a reaction wall, namely, the second duct (e.g., an air distribution duct). In the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with another standardized flexible duct segment after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segment is gradually opened, during which the air discharge to the outdoor ground by the system is not affected, so as to achieve the object of improving the pipe jacking efficiency without influence or interruption of the pipe jacking process.

[0023] In the above technical solution, the second air duct includes a plurality of flexible short pipes detachably interconnected, and the flexible short pipes are increased corresponding to newly hoisted pipe segments.

[0024] In the present technical solution, the second air duct is composed of flexible short pipes, namely, standardized flexible air duct segments. As mentioned above, in the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with newly added standardized flexible duct segments after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segments are gradually opened, during which the air discharge to the ground outdoor by the system is not affected, so as to achieve the object of improving the pipe jacking efficiency without influence or interruption of the pipe jacking process.

[0025] In the above technical solution, the flexible short pipes realize the detachable interconnection by use of pipe joints; or the flexible short pipes realize the detachable interconnection by use of a zipper structure.

[0026] In the present technical solution, all of the flexible short pipes, namely, all of the standardized flexible air duct segments, may be interconnected in the form of pipe joint connection or zipper structure to ensure the above connection process.

[0027] In the above technical solution, regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of a tool pipe, where the jet is at a distance of not less than 1 meter from the tunnelling head, thus facilitating the airflow in rebounding and swirling.

[0028] In the present technical solution, as mentioned above, the rebound and swirl of the airflow is ensured by use of the above arrangement.

[0029] In the above technical solution, average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s.

[0030] In the present technical solution, as mentioned above, the average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s to ensure the tightness of the air seal by the air curtain. It is a matter of course that the velocity may be adjusted and optimized according to actual working conditions.

[0031] In the above technical solution, an average flow velocity of the exhaust device is not less than 1 m / s, and the first air vent is disposed at the top within 5 meters from the tunnelling head.

[0032] In the present technical solution, in order to guarantee the replacement effect, the velocity of the exhaust device and the location of the first air vent are specified. Again, the above parameters may be optimized and adjusted according to actual working conditions.

[0033] In the above technical solution, more than 50% air supply at the tunnelling head is supplemented by the air curtain, and the negative pressure in the area between the air curtain and the tunnelling head is higher than that in other areas of a pipe jacking system.

[0034] In the present technical solution, as mentioned above, by increasing the negative pressure value of the area where the toxic and harmful gases disperse, the toxic and harmful gases are further prevented from overflowing, thus optimizing the operation environment of an overall jacking pipeline.

[0035] As can be appreciated that the negative pressure air-seal induced system for controlling the environment of pipe jacking operation provided by the present invention has the following beneficial effects:

[0036] The toxic and harmful gases are sealed between the air curtain and the tunnelling head to prevent large-range escape; by use of the resulting steady ascending airflow, the toxic and harmful gases with complex components and large difference in relative molecular mass are efficiently exhausted at a time, so that a wide adaptability is achieved; through design of the angle and the velocity of the air curtain, the exhaust ventilation efficiency of the toxic and harmful gases is improved depending on the replacement effect formed by continuous discharge with the exhaust system; by increasing the negative pressure value of the area where the toxic and harmful gases disperse, the toxic and harmful gases are further prevented from overflowing, thus optimizing the operation environment of an overall jacking pipeline; and the pipe jacking efficiency is improved without influence or interruption of the pipe jacking process.

[0037] The additional aspects and advantages of the present invention would become clear from the description below or would be understood through the practice of the present invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The additional aspects and advantages mentioned above and / or attached would be clear and easy to understand from the following description of embodiments in conjunction with the accompanying drawings, wherein:

[0039] FIG. 1 is a schematic diagram of the negative pressure air-seal induced system for controlling the environment of pipe jacking operation of the present invention;

[0040] FIG. 2 is a side cross-sectional view of the negative pressure air-seal induced system for controlling the environment of pipe jacking operation of the present invention.

[0041] Wherein, the corresponding relationship between reference numerals and component names in FIGS. 1 and 2 is as follows:

[0042] 1—turbulent airflow supply device, 2—exhaust device, 201—first air vent, 202—second air vent, 203—exhaust fan, 204—first air duct, 205—second air duct, 206—third air duct, 3—tunnelling head, 4—tool pipe.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] The present invention will be further described in detail in combination with accompanied drawings and embodiments for clear understanding of the above objects, features and advantages of the present invention. It should be noted that the features in the embodiments and the embodiments of the present application can be combined with each other in a non-conflicting situation.

[0044] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can also be implemented in other ways different from those described here, so the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0045] Referring to FIGS. 1 and 2, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation provided according to some embodiments of the present invention is described below.

[0046] According to some embodiments of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided.

[0047] As shown in FIGS. 1 and 2, according to the first embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, which includes:

[0048] a turbulent airflow supply device 1 provided at a certain distance from a tunnelling head 3 and located in a tool pipe 4, wherein the turbulent airflow supply device 1 forms anair curtain sealing structure at a certain angle with respect to the tunnelling head 3, the airflow rebounds and swirls between the air curtain and the tunnelling head 3 to form an air turbulence vortex, so that the toxic and harmful gases are fully stirred and mixed to form a steady ascending airflow;

[0049] and an exhaust device 2 provided in the tool pipe 4, wherein a first air vent 201 of the exhaust device 2 is located between the tunnelling head 3 and the turbulent airflow supply device 1 to collect and receive the toxic and harmful gases, and a second air vent 202 is located above ground to discharge the toxic and harmful gases off-site.

[0050] The negative pressure air-seal induced system for controlling the environment of pipe jacking operation provided by the present invention includes the turbulent airflow supply device 1 and the exhaust device 2. Wherein the turbulent airflow supply device 1 is used to form the air-seal structure of the air curtain, which is used to effectively restrain the toxic and harmful gases invading the tool pipe 4 through the front-end tunnelling head 3 in the area, thus preventing the toxic and harmful gases from further escape. Wherein regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of the tool pipe 4, where the jet is at a distance of not less than 1 meter from the tunnelling head 3, thus facilitating the airflow in rebounding and swirling (if possible, CFD simulation with the jet angle and an average flow velocity of the air curtain is carried out to accurately determine the jet angle and the average flow velocity according to the simulation results). In addition, the average flow velocities at different jet angles are not less than 0.5 m / s to ensure the tightness of the air seal. By controlling the jet angle and the average flow velocity, an air turbulence vortex is formed in the whole space of the tool pipe 4, so that various toxic and harmful gases with different relative molecular masses are fully stirred and mixed to form a steady ascending airflow, thus lessening the difficulty of collecting the toxic and harmful gases. On such basis, the present technical solution adds the exhaust device 2. After the air curtain forms a steady ascending airflow, the first air vent 201 disposed at the top continues the discharge to achieve a replacement effect, thus improving the exhaust ventilation efficiency of the toxic and harmful gases. In addition, the negative pressure between the air curtain and the tunnelling head 3 is higher than that in other areas of the pipe jacking system, further preventing the toxic and harmful gases from overflowing and optimizing the operation environment of an overall jacking pipeline, so as to achieve the objects of hierarchical increment of the negative pressure, replacement and supplement of the fresh air, hierarchical concentration-based control of the toxic and harmful gases and optimization of the ventilation efficiency.

[0051] According to the second embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, wherein, on the basis of the first embodiment, the exhaust device 2 further includes:

[0052] an exhaust fan 203 provided in the tool pipe 4;

[0053] a first air duct 204 communicated with the exhaust fan 203, wherein the first air duct 204 is located in the tool pipe 4, and the first air vent 201 is a port of the first air duct 204;

[0054] a second air duct 205 communicated with the exhaust fan 203, wherein the second air duct 205 is at least located in a jacking pipe;

[0055] a third air duct 206 communicated with the second air duct 205 and having an air outlet located above ground to form the second air vent 202;

[0056] wherein the first air duct 204, the second air duct 205 and the third air duct 206 form an exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head 3 are discharged on the ground.

[0057] In the present embodiment, the first air duct 204, the second air duct 205 and the third air duct 206 form the exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head 3 are discharged on the ground. The first air duct 204 is in a rigid structure, and the first air vent 201 is disposed at the top within 5 meters from the tunnelling head 3, and the exhaust fan 203 is set relative to the average flow velocity of not less than 1 m / s in the jacking pipe. The second air duct 205 is in a flexible structure, with one end connected with the exhaust fan 203 and the other end detachably connected with the third air duct 206, and the second air duct 205 is located in the tool pipe 4. In this way, the air curtain is integrally disposed in the tool pipe 4, thus reducing the pipeline structure and works (e.g., any pipeline connection) after jacking under the ground. The exhaust fan 203 is disposed between the air curtain and the tunnelling head 3, and a standardized flexible duct segment is provided between the exhaust fan 203 and a reaction wall, namely, the second duct 205 (e.g., an air distribution duct). In the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with another standardized flexible duct segment after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segment is gradually opened, during which the air discharge to the outdoor ground by the system is not affected, so as to achieve the object of improving the pipe jacking efficiency without influence or interruption of the pipe jacking process.

[0058] According to the third embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, the second air duct 205 includes a plurality of flexible short pipes detachably interconnected, and the flexible short pipes are increased corresponding to newly hoisted pipe segments.

[0059] In the present embodiment, the second air duct 205 is composed of flexible short pipes, namely, standardized flexible air duct segments. As mentioned above, in the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with newly added standardized flexible duct segments after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segments are gradually opened, during which the air discharge on the ground outdoor by the system is not affected, so as to achieve the object of improving the pipe jacking efficiency without influence or interruption of the pipe jacking process.

[0060] According to the fourth embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, the flexible short pipes realize the detachable interconnection by use of pipe joints; or the flexible short pipes realize the detachable interconnection by use of a zipper structure.

[0061] In the present embodiment, all of the flexible short pipes, namely, all of the standardized flexible air duct segments, may be interconnected in the form of pipe joint connection or zipper structure to ensure the above connection process.

[0062] According to the fifth embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of the tool pipe 4, where the jet is at a distance of not less than 1 meter from the tunnelling head 3, thus facilitating the airflow in rebounding and swirling.

[0063] In the present embodiment, as mentioned above, the rebound and swirl of the airflow is ensured by use of the above arrangement.

[0064] According to the sixth embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s.

[0065] In the present embodiment, as mentioned above, the average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s to ensure the tightness of the air seal by the air curtain. It is a matter of course that the velocity may be adjusted and optimized according to actual working conditions.

[0066] According to the seventh embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, an average flow velocity of the exhaust device 2 is not less than 1 m / s, and the first air vent 201 is disposed at the top within 5 meters from the tunnelling head 3.

[0067] In the present embodiment, in order to guarantee the replacement effect, the velocity of the exhaust device 2 and the location of the first air vent 201 are specified. Again, the above parameters may be optimized and adjusted according to actual working conditions.

[0068] According to the eighth embodiment of the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, more than 50% air supply at the tunnelling head 3 is supplemented by the air curtain, and the negative pressure in the area between the air curtain and the tunnelling head 3 is higher than that in other areas of a pipe jacking system.

[0069] In the present embodiment, as mentioned above, by increasing the negative pressure value of the area where the toxic and harmful gases disperse, the toxic and harmful gases are further prevented from overflowing, thus optimizing the operation environment of an overall jacking pipeline.

[0070] In the description, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be appropriately combined in any one or more embodiments or examples.

[0071] Any modification, equivalent replacement and improvement made within the spirit and rule of the present invention shall be incorporated in the protection scope of the present invention.

Examples

first embodiment

[0047]As shown in FIGS. 1 and 2, according to the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, which includes:[0048]a turbulent airflow supply device 1 provided at a certain distance from a tunnelling head 3 and located in a tool pipe 4, wherein the turbulent airflow supply device 1 forms anair curtain sealing structure at a certain angle with respect to the tunnelling head 3, the airflow rebounds and swirls between the air curtain and the tunnelling head 3 to form an air turbulence vortex, so that the toxic and harmful gases are fully stirred and mixed to form a steady ascending airflow;[0049]and an exhaust device 2 provided in the tool pipe 4, wherein a first air vent 201 of the exhaust device 2 is located between the tunnelling head 3 and the turbulent airflow supply device 1 to collect and receive the toxic and harmful gases, and a second air vent 202 is located above ground to discharge the...

third embodiment

[0058]According to the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, the second air duct 205 includes a plurality of flexible short pipes detachably interconnected, and the flexible short pipes are increased corresponding to newly hoisted pipe segments.

[0059]In the present embodiment, the second air duct 205 is composed of flexible short pipes, namely, standardized flexible air duct segments. As mentioned above, in the process of hoisting a newly hoisted pipe segment, an air duct union (e.g., a zipper) located in a working shaft is opened, during which the exhaust air is directly discharged into the working shaft for a short time, and then the air duct is connected with newly added standardized flexible duct segments after hoisting in place. During the jacking process of a new pipe, the newly connected standardized flexible air duct segments are gradu...

fourth embodiment

[0060]According to the present invention, a negative pressure air-seal induced system for controlling the environment of pipe jacking operation is provided, on the basis of any of the above embodiments, the flexible short pipes realize the detachable interconnection by use of pipe joints; or the flexible short pipes realize the detachable interconnection by use of a zipper structure.

[0061]In the present embodiment, all of the flexible short pipes, namely, all of the standardized flexible air duct segments, may be interconnected in the form of pipe joint connection or zipper structure to ensure the above connection process.

Claims

1. A negative pressure air-seal induced system for controlling the environment of pipe jacking operation, characterized by comprising:a turbulent airflow supply device provided at a certain distance from a tunnelling head and located in a tool pipe, wherein the turbulent airflow supply device forms an air curtain sealing structure at a certain angle to the tunnelling head, the airflow rebounds and swirls between the air curtain and the tunnelling head to form an air turbulence vortex, so that the toxic and harmful gases are fully stirred and mixed to form a steady ascending airflow;and an exhaust device provided in the tool pipe, wherein a first air vent of the exhaust device is located between the tunnelling head and the turbulent airflow supply device to collect and receive the toxic and harmful gases, and a second air vent is located above ground to discharge the toxic and harmful gases off-site.

2. The negative pressure air-seal induced system for controlling the environment of pipe jacking operation according to claim 1, characterized in that the exhaust device further comprises:an exhaust fan provided in the tool pipe;a first air duct communicated with the exhaust fan, wherein the first air duct is located in the tool pipe, and the first air vent is a port of the first air duct;a second air duct communicated with the exhaust fan, wherein the second air duct is at least located in a jacking pipe;a third air duct communicated with the second air duct and having an air outlet located above ground to form the second air vent;wherein the first air duct, the second air duct and the third air duct form an exhaust passage for the toxic and harmful gases, so that the toxic and harmful gases between the air curtain and the tunnelling head are discharged on the ground.

3. The negative pressure air-seal induced system for controlling the environment of pipe jacking operation according to claim 2, characterized in that the second air duct comprises a plurality of flexible short pipes detachably interconnected, and the flexible short pipes are increased corresponding to newly hoisted pipe segments.

4. The negative pressure air-seal induced system for controlling the environment of pipe jacking operation according to claim 3, characterized in that the flexible short pipes realize the detachable interconnection by use of pipe joints; or the flexible short pipes realize the detachable interconnection by use of a zipper structure.

5. The negative pressure air-seal induced system for controlling the environment of pipe jacking operation according to claim 4, characterized in that regarding a jet angle of the air curtain, a jet distance is calculated relative to an isothermal jet defined hydromechanically, so as to ensure that the jet reaches the bottom of the tool pipe, where the jet is at a distance of not less than 1 meter from the tunnelling head, thus facilitating the airflow in rebounding and swirling.

6. The negative pressure air-seal induced system for controlling the environment of pipe jacking operation according to claim 1, characterized in that average flow velocities of the air curtain at different jet angles are not less than 0.5 m / s.

7. The negative pressure air-seal induced system for controlling the environment of pipe jacking operation according to claim 1, characterized in that an average flow velocity of the exhaust device is not less than 1 m / s, and the first air vent is disposed at the top within 5 meters from the tunnelling head.

8. The negative pressure air-seal induced system for controlling the environment of pipe jacking operation according to claim 1, characterized in that more than 50% air supply at the tunnelling head is supplemented by the air curtain, and the negative pressure in the area between the air curtain and the tunnelling head is higher than that in other areas of a pipe jacking system.

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