A circulating ventilation and cooling system for shield tunnel construction operation section and a construction method thereof

Abstract

The present invention provides a circulating ventilation and cooling system and construction method for the shield tunnel construction operation section, comprising: an air supply system for conveying external air to the interior of the shield tunnel; a secondary air supply system for cooling the air conveyed to the interior of the shield tunnel by the air supply system, and then pressing the cooled air to the front end of the shield tunnel construction; a control system for controlling the operation of the secondary air supply system to adjust the shield construction environment temperature and the wind speed at the operating end to ensure a comfortable shield construction environment; an exhaust system for removing dust from the hot and humid polluted gas inside the shield tunnel, and discharging the dust-removed polluted gas to the outside of the shield tunnel. The present invention combines pressure-in and exhaust-type ventilation, while taking into account the cooling and dust removal effects, effectively solving the ventilation and cooling problems inside the shield tunnel, avoiding slow shield tunneling due to poor exhaust and excessive temperature in the tunnel, thereby improving the existing ventilation method and the construction environment.

Description

Technical Field

[0001] The present invention relates to the field of shield tunnel engineering construction, and in particular to a circulating ventilation and cooling system for a shield tunnel construction operation section and a construction method. Background Art

[0002] With the development of the national economy and the acceleration of tunnel construction, shield tunneling has become widely used due to its economic and efficient performance. During shield tunneling, construction operations generate significant heat. Combined with the tunnel's narrow space and poor ventilation, this creates a harsh, hot and humid construction environment, severely impacting the health and work efficiency of construction workers. Therefore, appropriate measures are needed to address tunnel ventilation and cooling issues to ensure economical, safe, and efficient shield tunneling.

[0003] Good ventilation is a crucial factor in ensuring the progress of shield tunnel construction and improving construction efficiency. In their paper, "Research on Ventilation Schemes for Large-Diameter, Long-Distance Shield Construction Tunnels in the Sutong GIL Integrated Pipeline Corridor Project," presented at the 2018 National Engineering Geology Academic Annual Conference, Zhang Xiaoping et al. studied and analyzed the ventilation conditions of the Sutong GIL integrated pipeline corridor's cross-river tunnels. They pointed out that my country lacks experience in ventilation for single-track, long tunnel construction, and that effective ventilation still faces severe challenges. As early as 2003, Academician Wang Mengshu, in his article "China is the country with the most tunnels and underground projects in the world, the most complex, and the fastest-growing in the future," published in Railway Standard Design, emphasized the importance of reducing investment in tunnel ventilation during future tunnel construction. Therefore, to ensure the economy, practicality, safety, environmental protection, and ease of management of shield tunnel construction, it is necessary to propose a circulating ventilation and cooling system and construction method for the operating section of shield tunnel construction.

[0004] Currently, forced-in ventilation is the most widely used method for ventilating and cooling shield tunnels. This involves using fans to force fresh air from outside the tunnel through air ducts. However, this method does not reduce the heat generated by shield tunneling operations, and the polluted air inside the tunnel can further pollute the central working environment during its outflow. Furthermore, to improve the humidity and temperature of the working area, some construction sites use air conditioning systems for cooling. However, the heat generated by air conditioning is also directly discharged into the tunnel, and forced-in ventilation cannot effectively expel the hot and humid air. Furthermore, some construction sites use ice cooling, which involves placing ice near the working surface. However, this method requires the continuous addition of ice, and the mist produced by the melting ice can affect the safe use of electrical equipment in the tunnel, seriously affecting the normal operation of the shield tunnel.

[0005] A search of existing technical literature revealed that Chinese patent publication number CN111075495A discloses an air cooling device for secondary ventilation cooling of a shield machine and its operating method. The device uses a secondary ventilation cooler and a compression condensing unit for cooling. However, the compression condensing unit is composed of multiple compressors with separate refrigeration cycle systems connected in parallel, making the device bulky, complex, and cost-effective. It also fails to achieve a high ventilation rate. Another Chinese patent publication number CN209724398U discloses a tunnel ventilation system using semiconductor refrigeration. This system places a fan and cooler at the tunnel entrance, with air ducts running through the entire tunnel. However, this system has high fan power requirements and high energy consumption, resulting in low ventilation efficiency within the tunnel.

[0006] Therefore, there is an urgent need to propose a practical circulating ventilation and cooling system for the shield tunnel construction operation section with simple structure, energy saving and high efficiency. Summary of the Invention

[0007] In view of the defects in the prior art, the purpose of the present invention is to provide a circulating ventilation and cooling system and a construction method for the operation section of a shield tunnel construction.

[0008] A first aspect of the present invention provides a circulating ventilation and cooling system for a shield tunnel construction operation section, comprising:

[0009] The air supply system delivers external air to the shield tunnel, achieving primary air supply for the shield tunnel;

[0010] A secondary air supply system cools the air delivered to the shield tunnel by the air supply system and then compresses the cooled air to the front end of the shield tunnel construction;

[0011] A control system for controlling the operation of the secondary air supply system to adjust the shield construction environment temperature and the wind speed at the operating end to ensure a comfortable shield construction environment;

[0012] The exhaust system removes dust from the hot and humid polluted gas inside the shield tunnel and discharges the dust-removed polluted gas to the outside of the shield tunnel.

[0013] Preferably, the air supply system includes:

[0014] A main fan is provided at the shield tunnel entrance to provide external air to the shield tunnel;

[0015] The main air duct is arranged at the top of the tunnel segment, one end of the main air duct is connected to the air outlet of the main fan, and the other end of the main air duct extends to the vicinity of the heat source area at the tail of the trolley near the tunnel entrance, which can draw external air into the interior of the shield tunnel.

[0016] Preferably, the secondary air supply system includes:

[0017] A secondary fan is provided at the rear of the trolley near the tunnel entrance. The secondary fan is a pressure fan that can pressurize the air and increase the air flow rate.

[0018] A secondary air duct is provided at the top of the tunnel segment. One end of the secondary air duct is flexibly connected to the air outlet of the secondary fan. The other end of the secondary air duct extends to the junction of the trolley and the shield tail near the shield tail, and can guide air to the front end of the tunnel construction face.

[0019] A cooler is provided at the connection portion between the secondary fan and the secondary air duct, and is used to cool the air output by the secondary air supply system; the cooler adopts a semiconductor cooler, and the semiconductor cooler includes a plurality of semiconductor cooling plates, and the plurality of semiconductor cooling plates are evenly arranged in front of the fan blades of the secondary fan.

[0020] Preferably, the control system includes:

[0021] A temperature sensor is provided on the outside of the air outlet of the secondary air duct, and is used to collect the temperature of the air output by the secondary air duct;

[0022] A wind speed sensor is provided on a trolley near the shield tail and is used to measure the wind speed in the operating section after the secondary air supply system inputs air to the front end of the shield tunnel construction;

[0023] A control box, wherein the input end of the control box is connected to the output end of the temperature sensor and the wind speed sensor, and the output end of the control box is connected to the secondary fan and the refrigerator. The control box can receive and process the received signals in real time and feed back the results, thereby controlling the operation of the secondary fan and the refrigerator.

[0024] Preferably, the ventilation system comprises:

[0025] A trolley fan is provided at the head of the trolley near the tunnel entrance, and is used to extract the air inside the shield tunnel and discharge it to the outside of the tunnel, thereby enhancing the air convection inside the shield tunnel;

[0026] An air outlet pipe is provided at the lower side of the tunnel, one end of the air outlet pipe is connected to the air outlet of the trolley fan, and the other end of the air outlet pipe extends to the tunnel entrance;

[0027] A dust collector is arranged on a trolley near the tunnel entrance and is located at the connection between the trolley fan and the air outlet pipe, and is used to remove and collect dust from the air inside the shield tunnel extracted by the trolley fan.

[0028] A second aspect of the present invention provides a construction method for circulating ventilation and cooling in the operating section of a shield tunnel construction, which is performed using the above-mentioned circulating ventilation and cooling system for the operating section of a shield tunnel construction. The construction method comprises:

[0029] The air supply system is installed at the entrance of the shield tunnel to transport external air into the shield tunnel, thus achieving primary air supply for the shield tunnel;

[0030] A secondary air supply system is installed inside the shield tunnel and located in the trolley area at the front end of the tunnel. The secondary air supply system cools the air delivered to the shield tunnel by the air supply system and then compresses the cooled air to the front end of the shield tunnel construction face.

[0031] The exhaust system is installed inside the shield tunnel and located in the middle of the tunnel. The air outlet of the exhaust system extends to the tunnel entrance. The exhaust system removes dust from the hot and humid polluted air inside the shield tunnel and discharges the dust-removed polluted air to the outside of the shield tunnel.

[0032] The control system is installed inside the shield tunnel to collect the air temperature output by the secondary air supply system and the wind speed in the shield tunnel construction operation section, and the collected temperature and wind speed data are compared with the temperature setting threshold and wind speed setting threshold respectively and judged. The operation of the secondary air supply system is controlled according to the judgment result to adjust the shield construction environment temperature and the operating section wind speed to ensure the comfort of the shield construction environment.

[0033] Preferably, the construction method of circulating ventilation and cooling in the shield tunnel construction operation section is:

[0034] The installation of the air supply system at the shield tunnel entrance includes: installing a main fan of the air supply system at the shield tunnel entrance, fixing a main air duct to the top of the tunnel segment and laying it along the longitudinal direction of the tunnel, connecting one end of the main air duct to the air outlet of the main fan, and extending the other end to the heat source area near the rear of the trolley near the tunnel entrance;

[0035] The method of installing the secondary air supply system inside a shield tunnel and locating it in the trolley area at the front end of the tunnel includes: installing the secondary air supply system's secondary fan on a trolley near the tunnel entrance; fixing the secondary air duct to the top of the tunnel segment and laying it longitudinally along the tunnel; connecting one end of the secondary air duct to the secondary fan's air outlet and extending the other end to the shield tail, i.e., the front end of the shield tunnel construction; installing a cooler at the connection between the secondary fan and the secondary air duct, and evenly arranging multiple semiconductor cooling chips inside the cooler in front of the blades of the secondary fan;

[0036] -The exhaust system is installed inside the shield tunnel and located in the middle of the tunnel, including: installing the trolley fan of the exhaust system on a trolley near the tunnel entrance, fixing the air outlet pipe at the lower side of the inside of the shield tunnel and laying it longitudinally along the tunnel, and connecting one end of the air outlet pipe to the air outlet and extending the other end to the tunnel entrance; installing a dust collector at the connection between the trolley fan and the air outlet pipe.

[0037] Preferably, the control system is installed inside the shield tunnel, including:

[0038] Fixing the temperature sensor on the outside of the air outlet end of the secondary air duct;

[0039] Fix the wind speed sensor on the trolley near the tail of the shield;

[0040] The control box is installed in the control room of the trolley near the shield tail, the signal receiving end of the control box is connected to the temperature sensor and the wind speed sensor, and the signal output end of the control box is connected to the secondary fan and the refrigerator.

[0041] Preferably, the parameter values ​​of the control system are set, wherein:

[0042] Set the upper threshold value [T1] of the temperature sensor data:

[0043] [T1] = (1-10%) T GB

[0044] Among them, T GB The upper limit of the construction environment temperature set for the implementation of the standards;

[0045] Set the lower threshold value [T2] of the temperature sensor data:

[0046] [T2] ​​= (1 + 15%) T SF

[0047] Among them, T SF The temperature that humans feel comfortable in summer is the lower limit of 19℃-24℃. SF =19℃;

[0048] Set the upper threshold value [V1] of the wind speed sensor data:

[0049] [V1] = (1-5%) V max

[0050] Among them, V max The upper limit of wind speed in the construction environment set by the implementation standard;

[0051] Set the lower threshold value [V2] of the wind speed sensor data:

[0052] [V2]=max(VT ,V GB )

[0053] Among them, V GB The minimum wind speed allowed in the tunnel as specified in the implementation standard; V T The tunnel ventilation meets the cooling requirements, that is, the operating section temperature is the maximum allowable value T max The wind speed at that time, V T The energy conservation equation can be established based on the real-time temperature T of the gas fed into the secondary air duct fed back by the temperature sensor to obtain:

[0054] c·ρgA(t1+t2)V T ·(T max -T)=κJW(1-η)t1

[0055] Where c is the specific heat capacity of the air in the tunnel; ρ is the density of the air in the tunnel; g is the acceleration of gravity; A is the cross-sectional area of ​​the tunnel through which the wind passes; t1 is the time it takes for each shield ring to be driven; t2 is the time it takes for each shield ring to be assembled; T max is the upper limit of the temperature in the tunnel operation section; T is the real-time temperature fed back by the temperature sensor; κ is the correction coefficient considering the actual situation of the tunnel; J is the thermal equivalent, J = 3600 kJ / kWh; W is the total power of the shield machine; η is the total efficiency of the system.

[0056] Preferably, the collected temperature and wind speed data are compared with the temperature and wind speed set thresholds and judged, and the operation of the secondary air supply system is controlled according to the judgment result, including the following three operating conditions:

[0057] Case 1: the control system controls the secondary air supply system to ventilate normally;

[0058] When the temperature of the gas injected into the front end of the shield tunnel construction meets the requirements, that is, [T2]≤T≤[T1], and the wind speed in the shield tunnel construction operation section is also within the specified range, that is, [V2]≤V≤[V1], the secondary air supply system is controlled to operate normally;

[0059] Case 2: When the input gas temperature does not meet the requirement, the control system adjusts the working state of the refrigerator;

[0060] When the input gas temperature is not within the specified range, that is, T>[T1] or T<[T2]: When the input gas temperature is high, that is, T>[T1], the number of working operations of the refrigerator semiconductor refrigeration piece is increased according to the test result; when the input gas temperature is low, that is, T<[T2], the number of working operations of the refrigerator semiconductor refrigeration piece is reduced according to the test result;

[0061] Case 3: When the wind speed in the operating section does not meet the requirement, the control system adjusts the working state of the secondary fan;

[0062] When the wind speed in the operating section is not within the specified range, that is, V>[V1] or V<[V2]: when the wind speed in the operating section is too large, that is, V>[V1], the operating frequency of the secondary fan is reduced according to the detection result; when the wind speed in the operating section is too small, that is, V<[V2], the operating frequency of the secondary fan is increased according to the detection result.

[0063] The working principles of the above-mentioned shield tunnel construction operation section circulating ventilation and cooling system and construction method are as follows:

[0064] The air supply system, secondary air supply system, control system, and exhaust system are installed in the shield tunnel construction operation section. The parameter values ​​of the control box of the control system are set, and the power is turned on to start the equipment. When the air supply system is working, fresh air from the outside is pressed into the tunnel through the main air duct. Some of the air enters the tunnel for convection, while most of it is powered by the secondary fan of the secondary air supply system and continues to be transported to the tunnel shield construction area. It is first cooled by the refrigerator and then transported to the shield tail through the secondary air duct to achieve ventilation and cooling of the shield construction area. When the cold air passes through the heat source area, it takes away heat, dust, and moisture, forming hot and humid polluted gas. When this gas flows to the trolley near the tunnel entrance, most of it is first sucked in by the trolley fan and then dedusted by the dust collector. The hot and humid gas after dust removal is transported to the tunnel entrance (the tunnel entrance) through the outlet duct and discharged to the outside of the tunnel, avoiding pollution of the working environment in the middle of the tunnel. The temperature sensor and wind speed sensor of the control system will collect environmental parameters in real time and feed them back to the control box. If the temperature sensor data T and wind speed sensor data V fed back by the sensor during operation are within the threshold range (i.e. [T2]≤T≤[T1] and [V2]≤V≤[V1]), the system will continue to operate, indicating that the tunnel is ventilated normally; if the temperature sensor data T fed back by the sensor during operation exceeds the threshold (i.e. T>[T1] or T<[T2]), the control box will increase or decrease the number of working semiconductor refrigeration plates of the refrigerator according to the test results; if the wind speed sensor data V fed back by the sensor during operation exceeds the threshold (i.e. V>[V1] or V<[V2]), the control box will adjust the operating frequency of the secondary fan according to the test results. The entire system implements multiple air circulation ventilation: the supply air system, secondary air supply system, and exhaust air system form the first large circulation; external air reaches the front of the shield through the supply air system and secondary air supply system, returning to the tunnel entrance with heat, forming the second small circulation; and external air passes through the supply air system and is carried out of the tunnel by the wind from the front of the shield, forming the third small circulation. This multi-circulation ventilation achieves normal ventilation of the tunnel with low energy consumption, ensuring a comfortable shield construction environment and ensuring efficient shield tunneling.

[0065] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0066] The above-mentioned system of the present invention combines push-in and exhaust ventilation by setting up an air supply system, a secondary air supply system and an exhaust system, and takes into account the cooling and dust removal effects. It can effectively solve the ventilation and cooling problems inside the shield tunnel, and avoid slow shield excavation due to poor exhaust and excessive temperature in the tunnel, thereby improving the existing ventilation method and improving the construction environment. The above-mentioned system has a simple structure, is safe and environmentally friendly, has high working efficiency, and has good social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Other features, objects and advantages of the present invention will become more apparent upon reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0068] Figure 1 This is a schematic diagram of the overall structure of the circulating ventilation and cooling system for the shield tunnel construction operation section of the present invention;

[0069] Figure 2 for Figure 1 Cross-sectional view along the AA axis;

[0070] Figure 3 for Figure 1 Cross-sectional view along the BB direction;

[0071] Figure 4 This is a control principle diagram of the control system of the circulating ventilation and cooling system for the shield tunnel construction operation section of the present invention.

[0072] The marks in the figure are: 1 is the main fan, 2 is the main air duct, 3 is the shield tunnel, 4 is the tunnel segment, 5 is the secondary fan, 6 is the cooler, 7 is the secondary air duct, 8 is the last section of the shield trolley, 9 is the control box, 10 is the first section of the shield trolley, 11 is the shield tail, 12 is the temperature sensor, 13 is the wind speed sensor, 14 is the trolley fan, 15 is the dust collector, 16 is the air outlet duct, 111 is the air supply system, 222 is the secondary air supply system, 333 is the control system, and 444 is the exhaust system. DETAILED DESCRIPTION

[0073] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those skilled in the art, several variations and improvements can be made without departing from the scope of the present invention. These all fall within the scope of protection of the present invention.

[0074] Reference Figure 1As shown, it is a schematic diagram of the overall structure of the circulating ventilation and cooling system of the shield tunnel construction operation section in a preferred embodiment of the present invention, which includes an air supply system 111, a secondary air supply system 222, a control system 333 and an exhaust system 444.

[0075] The air supply system 111 is arranged near the opening of the shield tunnel 3 to transport external air into the shield tunnel 3 , thereby achieving primary air supply for the shield tunnel 3 .

[0076] The secondary air supply system 222 is set inside the shield tunnel 3 and located in the trolley area at the front end of the tunnel. It is used to cool most of the air transported to the inside of the shield tunnel 3 by the air supply system, and then compress the cooled air to the front end of the shield tunnel 3 construction.

[0077] The control system 333 is arranged inside the shield tunnel 3 and is used to control the operation of the secondary air supply system to adjust the temperature of the shield construction environment to ensure a comfortable shield construction environment.

[0078] The exhaust system 444 is arranged inside the shield tunnel 3 and close to the middle of the shield tunnel 3 to remove dust from the hot and humid polluted gas inside the shield tunnel 3 and discharge the dust-removed polluted gas to the outside of the tunnel.

[0079] The operating principle of the above system is as follows: the air supply system 111, located at the tunnel entrance, presses fresh air from outside into the shield tunnel 3. Before the air entering the shield tunnel 3 reaches the secondary air supply system 222, part of the air enters the tunnel for convection. The majority of the air, powered by the secondary air supply system 222, is then transported to the tunnel shield construction area. This air is then cooled by the secondary air supply system 222 and transported to the connection area between the first shield trolley 10 and the shield tail 11, achieving ventilation and cooling of the shield construction area. After passing through the heat source area, the cooled air removes heat, dust, and moisture, forming hot and humid polluted gas. When this gas reaches the last shield trolley 8, most of the gas is first sucked in by the exhaust system 444 and filtered to remove dust. The dust-removed hot and humid gas is then transported to the tunnel entrance (tunnel entrance) through the outlet pipe 16 and discharged to the outside of the tunnel, avoiding contamination of the working environment in the middle of the tunnel. The control system 333 can collect parameters such as ambient temperature and wind speed in real time, detect ambient temperature, and automatically adjust the operating status of the secondary air supply system 222 based on the detection results. The system implements multiple gas circulation ventilation: the air supply system 111, the secondary air supply system 222, and the exhaust system 444 jointly form the first large circulation; the external air reaches the front of the shield through the air supply system 111 and the secondary air supply system 222, and returns to the tunnel entrance with heat, forming the second small circulation; the external air passes through the air supply system 111 and is carried out of the tunnel with the wind from the front of the shield, thus forming the third small circulation. Multi-circulation ventilation achieves normal ventilation of the tunnel with low energy consumption, ensuring a comfortable shield construction environment and efficient construction of the shield tunnel 3.

[0080] In other preferred embodiments, Figure 1 、 Figure 2 As shown, the air supply system 111 includes a main fan 1 and a main air duct 2; wherein the main fan 1 is installed at the entrance of the shield tunnel 3 to provide fresh air from outside to the interior of the shield tunnel 3. The main air duct 2 is fixed to the top of the tunnel segment 4 and laid along the longitudinal direction of the tunnel. One end of the main air duct 2 is connected to the air outlet of the main fan 1, and the other end of the main air duct 2 extends to the heat source area near the tail of the trolley near the tunnel entrance, which can guide external air into the interior of the shield tunnel 3. As a preferred embodiment, the main fan 1 adopts an axial flow fan. The use of this type of fan has the characteristics of low noise, high efficiency, and high reliability.

[0081] In other preferred embodiments, the main air duct 2 utilizes a flexible ventilation duct, which is a circular canvas ventilation duct. The canvas ventilation duct has the advantages of simple structure, low cost, and easy installation. Of course, other types of flexible ventilation ducts can be selected according to the specific construction conditions.

[0082] In other preferred embodiments, the canvas ventilation duct is constructed from multiple segments of canvas ventilation tubes spliced ​​together along the axial direction, with adjacent segments sealed and connected by zippers. The advantage of using these splicable segments is that the duct length can be extended accordingly with shield tunneling, making construction more convenient, improving efficiency, and shortening the construction period.

[0083] In other preferred embodiments, the secondary air supply system 222 includes a secondary fan 5, a secondary air duct 7 and a cooler 6; wherein, the secondary fan 5 is fixed to the tail of the last trolley 8 of the shield (the trolley near the entrance and the trolley near the tunnel entrance are just relative positions, and all the trolleys are located at the front end of the tunnel construction and are far away from the tunnel entrance), which can save working space. The secondary fan 5 is a pressurized fan, which can pressurize the air and speed up the flow rate of the wind; it provides power for most of the fresh air input by the air supply system 111 to the front end of the shield tunnel 3 construction. As a preferred method, the secondary fan 5 is arranged close to the outlet end of the main air duct 2.

[0084] The secondary air duct 7 is fixed to the top of the tunnel segment 4 and laid along the longitudinal direction of the tunnel. One end of the secondary air duct 7 is flexibly connected to the outlet of the secondary fan 5, which can reduce resonance generated by the secondary fan 5 and the secondary air duct 7, thereby reducing ventilation noise. The other end of the secondary air duct 7 extends to the junction of the first shield trolley 10 and the shield tail 11, which can guide air to the front end of the tunnel construction face. As a preferred embodiment, the secondary air duct 7 and the main air duct 2 are located on the same axis.

[0085] The cooler 6 is provided at the connection portion between the secondary fan 5 and the secondary air duct 7 , and is used to cool the air output by the secondary fan 5 .

[0086] In other preferred embodiments, the refrigerator 6 is a semiconductor refrigerator comprising a plurality of semiconductor cooling fins evenly arranged in front of the blades of the secondary fan 5. In specific implementations, the number of semiconductor cooling fins meets the maximum load requirements of the shield tunnel 3, and each semiconductor cooling fin is independently controlled by a control box 9, which can control the number of cooling fins in operation based on detection conditions.

[0087] In other preferred embodiments, the secondary air duct 7 adopts a rigid ventilation duct, which is a welded steel pipe. The outer surface of the steel pipe can be hot-dip or electroplated with a galvanized layer to achieve good ventilation and cooling; the galvanized steel pipe is a spiral seam circular air duct, which is connected by a flange. The air duct wall thickness and the spacing of the flange connection can be adjusted according to the required wind pressure and air duct diameter.

[0088] In other preferred embodiments, the control system 333 includes a temperature sensor 12, a wind speed sensor 13, and a control box 9. The temperature sensor 12 is disposed near the outer side of the air outlet end of the secondary air duct 7 to collect the temperature of the air output by the secondary air duct 7. As a preferred embodiment, the temperature sensor 12 can be a commercially available H7080 air duct temperature sensor 12.

[0089] The wind speed sensor 13 is fixed on the first trolley 10 of the shield machine to measure the wind speed of the construction environment after the secondary air supply system inputs air to the front end of the shield tunnel 3 construction.

[0090] The control box 9 is fixed to the first trolley 10 of the shield machine. The input end of the control box 9 is connected to the output end of the temperature sensor 12 and the wind speed sensor 13. The output end of the control box 9 is connected to the secondary fan 5 and the refrigerator 6. The control box 9 can receive and process the received signals in real time and feedback the results to control the operation of the secondary fan 5 and the refrigerator 6. The wind speed sensor 13 can use the commercially available product model NHFS45 wind speed sensor.

[0091] Reference Figure 4 As shown, the temperature sensor 12 and wind speed sensor 13 of the control system 333 collect environmental parameters in real time and feed them back to the control box 9. The control box 9 intelligently compares the obtained input parameters with the upper and lower thresholds of the parameters set in advance by the operator and makes a judgment. Then, based on the judgment result, the operation of the secondary air supply system is controlled, including the following three operating conditions:

[0092] Case 1: The control system 333 controls the secondary air supply system to ventilate normally;

[0093] When the temperature of the gas injected into the front end of the shield tunnel 3 construction meets the requirements, that is, [T2]≤T≤[T1], and the wind speed in the construction operation section of the shield tunnel 3 is also within the specified range, that is, [V2]≤V≤[V1], the secondary air supply system is controlled to operate normally.

[0094] Case 2: When the input gas temperature does not meet the requirement, the control system 333 adjusts the working state of the refrigerator 6;

[0095] When the input gas temperature is not within the specified range, that is, T>[T1] or T<[T2]: when the input gas temperature is too high, that is, T>[T1], the number of working operations of the refrigerator semiconductor refrigeration plate is increased according to the test results; when the input gas temperature is too low, that is, T<[T2], the number of working operations of the refrigerator semiconductor refrigeration plate is reduced according to the test results.

[0096] Case 3: When the wind speed in the operating section does not meet the requirement, the control system 333 adjusts the working state of the secondary fan;

[0097] When the wind speed in the operating section is not within the specified range, that is, V>[V1] or V<[V2]: when the wind speed in the operating section is too large, that is, V>[V1], the operating frequency of the secondary fan 5 is reduced according to the detection result; when the wind speed in the operating section is too small, that is, V<[V2], the operating frequency of the secondary fan 5 is increased according to the detection result.

[0098] In other preferred embodiments, the exhaust system 444 includes a trolley fan 14, a dust collector 15, and an exhaust pipe 16. The trolley fan 14 is mounted at the head of the last trolley 8 of the shield machine. The trolley fan 14 is an exhaust fan used to extract air from the interior of the shield tunnel 3 and exhaust it to the exterior, thereby enhancing air convection within the shield tunnel 3. The extracted air is exhaust gas from the front of the shield machine, which contains a large amount of dust. As a preferred embodiment, the horizontal distance between the trolley fan 14 and the secondary fan 5 is approximately the length of one shield trolley.

[0099] The dust collector 15 is installed on the last trolley 8 of the shield machine and is located at the connection between the trolley fan 14 and the air outlet pipe 16. It is used to remove and collect dust from the extracted air inside the shield tunnel 3 to avoid further diffusion and pollution of the dust.

[0100] The air outlet pipe 16 is fixed to the lower side of the tunnel and laid along the longitudinal direction of the tunnel to prevent pollution of the working environment in the middle of the tunnel. One end of the air outlet pipe 16 is connected to the air outlet of the trolley fan 14, and the other end of the air outlet pipe 16 extends to the tunnel entrance (tunnel opening). As a preferred embodiment, the air outlet pipe 16 adopts a flexible ventilation duct. The flexible ventilation duct is a circular canvas ventilation duct that adapts to the air outlet of the trolley fan 14. It includes multiple sections of canvas ventilation tubes connected by zippers. It has the characteristics of simple structure, low cost and easy installation.

[0101] In a specific application example, taking an intercity railway tunnel located in a certain province as an example, the above-mentioned shield tunnel construction operation section circulating ventilation and cooling system is used to ventilate and cool the interior of the tunnel during the tunnel excavation process to ensure the comfort of the construction environment and the efficient construction of the tunnel, thereby further explaining the structural characteristics of the shield tunnel construction operation section circulating ventilation and cooling system.

[0102] The tunnel is a double-hole, single-track tunnel. The single-track length of shield tunnel 3 is 2144.379m, and the construction mileage is DK35+550~DK37+700. The tunnel has an inner diameter of 8000mm and an outer diameter of 8800mm. It is constructed using a 9.1m diameter composite earth pressure balance shield machine. The circulating ventilation and cooling system of the construction operation section of shield tunnel 3 consists of four subsystems, including the air supply system 111, the secondary air supply system 222, the control system 333 and the exhaust system 444. The overall system structure is based on Figure 1 shown.

[0103] The air supply system 111 consists of a main fan 1 and a main air duct 2, which can press external fresh air into the tunnel to achieve primary air supply for the shield tunnel 3.

[0104] The main fan 1 is an SDF series NO12.5 energy-saving axial flow fan with a speed of 1480r / min, a wind pressure of 1300Pa-5500Pa, and an air volume of 1600m 3 / min-2950m 3 / min, high efficiency air volume 2400m 3 The main fan 1 is placed at the entrance of the shield tunnel 3. It has the characteristics of low noise, high efficiency, and high reliability, and can input a large amount of external fresh air into the shield tunnel 3.

[0105] The main air duct 2 is a flexible, circular canvas ventilation duct with a diameter of 1.2m. It consists of multiple sections of 1.2m diameter and 20m length canvas ventilators. Each section is connected using a three-star zipper seal with a strength of at least 2800N. This allows the duct's length to be extended as the shield advances, resulting in a simple structure, low cost, and easy installation. The main air duct 2 is secured to the top of the tunnel segment 4. One end of the duct is connected to the outlet of the main fan 1, and the other end extends to the heat source area at the rear of the trolley 8, directing air into the tunnel.

[0106] Shield Tunnel 3, constructed using a ZTE9100 composite earth pressure balance shield machine, has a single-track length of 2,144.379 meters. Its inner diameter is 8,000 mm and its outer diameter is 8,800 mm. The shield tunnel consists of six trolleys: the first trolley (10) is 9,300 mm long, the second trolley is 12,300 mm long, the third, fourth, and fifth trolleys are all 11,200 mm long, and the sixth and final trolley (8) is 13,125 mm long. The connection between the trolleys is 480 mm long, for a total length of 70,725 mm.

[0107] The secondary air supply system 222 consists of three parts, including a secondary fan 5, a cooler 6 and a secondary air duct 7, which can cool most of the air input by the air supply system and then press the cooled gas to the front end of the shield tunnel 3 construction.

[0108] The secondary fan 5 is a SDF-I-8II tunnel construction pipeline pressure fan with a total pressure of 539Pa, an impeller diameter of 800mm, a speed of 1480r / min, and an air volume of 30000m 3 / h, which can pressurize the wind and speed up the wind flow, and pressurize most of the fresh air input by the air supply system to the front end of the shield tunnel 3. The secondary fan 5 is fixed to the rear of the last trolley 8 of the shield to save working space.

[0109] Cooler 6 is composed of multiple semiconductor refrigeration chips. The number of chips meets the maximum load requirements of shield tunnel 3. The cooling capacity of the chips is determined by the number of P-type and N-type semiconductor elements. The chips are placed in front of the blades of secondary fan 5, and each chip is independently controlled by control box 9.

[0110] The secondary air duct 7 is a welded steel pipe with a wall thickness of 0.75mm and a diameter of 800mm, and a hot-dip galvanized layer is provided on the surface of the welded steel pipe. The steel pipe is a spiral seam circular air duct, connected by a flange made of 30*3 specification angle steel material. The spacing between the M8 specification bolts and rivets of the flange is 100mm. The secondary air duct 7 is fixed to the top of the tunnel segment 4. One end of the secondary air duct 7 is flexibly connected to the air outlet of the secondary fan 5, which can reduce the resonance generated by the secondary fan 5 and the secondary air duct 7 and reduce ventilation noise; the other end of the secondary air duct 7 extends to the junction of the first section trolley 10 of the shield and the shield tail 11. The air outlet of the secondary air duct 7 is set at a position about 15m away from the heading face, which can divert the wind to the front end of the tunnel construction and achieve good ventilation and cooling.

[0111] The control system 333 consists of three parts, including a temperature sensor 12, a wind speed sensor 13 and a control box 9. The control system 333 is used to control the operation of the secondary air supply system to ensure a comfortable shield construction environment. The control principle is as follows: Figure 4 shown.

[0112] The temperature sensor 12 is an H7080 type air duct temperature sensor, which is used to detect the temperature of the gas supplied by the secondary air supply system. It is fixed on the outside of the air outlet end of the secondary air duct 7, and the output signal is received by the control box 9.

[0113] The wind speed sensor 13 is an NHFS45 type wind speed sensor, which is used to measure the wind speed in the tunnel construction environment after the secondary air supply system inputs the air flow. It is fixed on the first section trolley 10 of the shield machine, and the output signal is received by the control box 9.

[0114] The control box 9 is a small programmable intelligent logic controller that receives and analyzes sensor signals in real time and provides feedback, thereby intelligently controlling the operation of the secondary air supply system's secondary blower 5 and chiller 6. The control box 9 is located in the control room on the first trolley 10 of the shield machine.

[0115] The exhaust system 444 is composed of three parts: a trolley fan 14, a dust collector 15 and an air outlet pipe 16. It can remove dust from the hot and humid polluted gas in the tunnel and pressurize the dust-removed air to the tunnel entrance and discharge it outside the tunnel.

[0116] Trolley fan 14 is a SDF-NO-11.2 tunnel axial flow fan with a speed of 960r / min, a total pressure of 636Pa, and an air volume of 1000m 3 / min. The SDF-NO-11.2 tunnel axial flow fan extracts air from the tunnel and exhausts it to the outside, enhancing convection within the tunnel. The SDF-NO-11.2 tunnel axial flow fan is installed at the head of the final trolley 8 of the shield tunnel, with the horizontal distance from the secondary fan 5 being approximately 13125mm, the length of the final trolley 8.

[0117] The dust collector 15 is a small dust removal device that filters and collects dust from the exhaust gases emitted by the shield tunneling machine, preventing further spread and contamination. The dust removal device is installed on the final trolley 8 of the shield machine and secured to the connection between the trolley's fan 14 and the exhaust pipe 16.

[0118] The air outlet duct 16 is a circular canvas ventilation duct with a diameter of 1.0m. It consists of multiple sections of 10m canvas ventilation tubes connected by a resin three-star zipper seal with a strength of at least 2800N. It has the characteristics of simple structure, low cost and easy installation. The circular canvas ventilation duct is fixed to the lower side of the tunnel, with one end connected to the air outlet of the trolley fan 14 and the other end extending to the tunnel entrance to prevent contamination of the working environment in the middle of the tunnel. The specific location of each air outlet duct 16 and the main air duct 2 can be seen in Figure 2 、 Figure 3 shown.

[0119] The components of the air supply system 111, the secondary air supply system 222, the control system 333 and the exhaust system 444 are connected in the following manner:

[0120] The main fan 1 of the air supply system 111 is installed at the entrance of the shield tunnel 3, with its air outlet connected to the main air duct 2, which is fixed to the top of the tunnel segment 4. The secondary fan 5 of the secondary air supply system 222 is fixed to the last trolley 8 of the shield tunnel, and the air outlet of the secondary fan 5 is flexibly connected to the secondary air duct 7, which is fixed to the top of the tunnel segment 4. The cooler 6 of the secondary air supply system 222 is installed at the connection between the secondary fan 5 and the secondary air duct 7. The multiple semiconductor cooling plates inside the cooler 6 are evenly arranged in front of the blades of the secondary fan 5. The temperature sensor 12 of the control system 333 is installed and fixed to the outside of the air outlet end of the secondary air duct 7, and the wind speed sensor 13 and the control box 9 are fixed to the first trolley 10 of the shield tunnel. Control box 9 receives the output signals of temperature sensor 12 and wind speed sensor 13. The signal output of control box 9 is connected to the secondary air supply system's secondary fan 5 and cooler 6. The trolley fan 14 of exhaust system 444 is located on the shield tunnel's final trolley 8. The air outlet of trolley fan 14 is connected to an air outlet duct 16, which is fixed to the lower side of the shield tunnel 3. A dust collector 15 is installed at the connection between trolley fan 14 and air outlet duct 16.

[0121] In the above application example, the shield tunnel construction operation section circulating ventilation and cooling system can realize multiple gas circulation ventilation inside the shield tunnel, achieving normal ventilation of the tunnel with low energy consumption, significantly improving the comfort of the construction environment and the construction efficiency of the shield tunnel, and ensuring the smooth advancement of the shield.

[0122] Based on the above-mentioned circulating ventilation and cooling system for the shield tunnel construction operation section, another application example provides a construction method for circulating ventilation and cooling for the shield tunnel construction operation section, which can be performed according to the following steps:

[0123] S1: Select the fan.

[0124] S10: Select parameters based on the actual conditions of shield tunnel construction and the combined ventilation method determined by the multiple-cycle ventilation and cooling system.

[0125] S11: Use traditional industry standard methods to calculate air volume and pressure to select ventilation equipment.

[0126] By using traditional methods for calculation, an SDF series NO12.5 energy-saving axial flow fan was selected as the main fan 1, an SDF-I-8II tunnel construction duct pressurized fan was selected as the secondary fan 5, and an SDF-NO-11.2 tunnel axial flow fan was selected as the trolley fan 14.

[0127] S2: Construction and installation of air supply system 111, secondary air supply system 222, control system 333 and exhaust system 444, refer to Figure 1 As shown, the overall schematic diagram of the system, refer to Figure 2As shown in FIG. 1 , the relative positions of the air ducts are determined by the following steps:

[0128] S20: Install the main fan 1 of the air supply system at the entrance of the shield tunnel 3, and fix the main air duct 2 to the top of the tunnel segment 4, with one end connected to the air outlet of the main fan 1 and the other end extending to the heat source area at the tail of the last trolley 8.

[0129] S21: Install the secondary fan 5 of the secondary air supply system on the last trolley 8 of the shield, fix the secondary air duct 7 to the top of the tunnel segment 4, and connect one end of the secondary air duct 7 to the air outlet of the secondary fan 5, and extend the other end to the junction of the first trolley 10 of the shield and the shield tail 11.

[0130] S22: Install the refrigerator 6 at the connection between the secondary fan 5 and the secondary air duct 7, and evenly place the multiple semiconductor cooling sheets inside the refrigerator 6 in front of the fan blades of the secondary fan 5.

[0131] S23: Install the trolley fan 14 of the exhaust system 444 on the head of the last trolley 8 of the shield machine, and fix the air outlet pipe 16 at the lower side of the inner side of the shield tunnel 3, with one end connected to the air outlet and the other end extending to the vicinity of the tunnel entrance.

[0132] S24: Install the dust collector 15 at the connection position between the trolley fan 14 and the air outlet pipe 16.

[0133] S3: Installing the relevant equipment of the control system 333, specifically including the following steps:

[0134] S31: Fix the temperature sensor 12 on the outer side of the air outlet end of the secondary air duct 7.

[0135] S32: Fix the wind speed sensor 13 on the first trolley 10 of the shield machine.

[0136] S33: Install the control box 9 in the control room of the first section trolley 10 of the shield machine, connect its signal receiving end with the temperature sensor 12 and the wind speed sensor 13 using a wire (or wirelessly), and connect its signal output end with the secondary fan 5 and the refrigerator 6 using a wire.

[0137] S4: Turn on the power supply, feed 220V AC power to the control system 333, start the control box 9, and set the parameter values ​​of the control system 333. Specifically, the following steps are included:

[0138] S41: Determine the upper threshold value [T1] of the temperature sensor 12 data of the control system 333:

[0139] [T1] = (1-10%) T GB

[0140] Among them, T GBThe upper limit of the construction environment temperature set by the implementation standard is adopted. In this embodiment, the upper limit of the temperature T recommended by the "Code for Construction and Acceptance of Shield Tunneling" (GB50446-2017) is adopted. GB =32℃, calculated [T1]=28.8℃.

[0141] S42: Determine the lower threshold value [T2] of the temperature sensor 12 data of the control system 333:

[0142] [T2] ​​= (1-15%) T SF

[0143] Among them, T SF The lower limit of the temperature that humans feel comfortable in summer is 19-24℃. SF =19°C. In this embodiment, [T2] = 16.15°C.

[0144] S43: Determine the upper threshold value [V1] of the wind speed sensor 13 data of the control system 333:

[0145] [V1] = (1-5%) V max

[0146] Among them, V max The maximum wind speed in the tunnel recommended by the Railway Tunnel Construction Code (TB10204-2002) is V max =6m / s, calculated [V1] = 5.7m / s.

[0147] S44: Determine the lower threshold [V2] of the wind speed sensor 13 data processed by the control system 333:

[0148] [V2]=max(V T ,V GB )

[0149] Among them, V GB V is the minimum wind speed allowed in the tunnel as specified in the standard; T To ensure that the tunnel ventilation meets the cooling requirements (i.e. the operating section temperature is the maximum allowable T max ), which can be obtained by establishing the energy conservation equation based on the real-time temperature T of the gas fed into the secondary air duct fed back by the temperature sensor 12:

[0150] c·ρgA(t1+t2)V T ·(T max -T)=κJW(1-η)t1

[0151] Where c is the specific heat capacity of the air in the tunnel; ρ is the density of the air in the tunnel; g is the acceleration of gravity; A is the cross-sectional area of ​​the tunnel through which the wind passes; t1 is the time it takes for each shield ring to be driven; t2 is the time it takes for each shield ring to be assembled; T max is the upper limit of the temperature in the tunnel operation section; T is the real-time temperature fed back by the temperature sensor 12; κ is the correction coefficient considering the actual conditions of factors such as tunnel length, cross-section size, and slope; J is the thermal equivalent, J=3600kJ / kWh; W is the total power of the shield machine; and η is the total efficiency of the system.

[0152] In this embodiment, the minimum wind speed allowed in the tunnel as specified in the Code for Construction and Acceptance of Shield Tunneling Methods (GB50446-2017) is adopted, V GB =0.25m / s; the specific heat capacity of air changes with temperature, and the specific heat capacity at 300K or 26.85℃ is approximately taken as c=1.005kJ / (kg·℃); the density of air is approximately taken as ρ=1.29kg / m 3 ; g = 9.8 m / s 2 ; A=πR 2 =50.265m 2 ;t1=30min=0.5h; t2=40min=2 / 3h; T max =T GB =32℃;κ=1.32;ZTE9100 composite earth pressure balance shield machine power W=4638kW;η=0.8;Finally, the calculated V T =0.8217 / (32-T), the lower threshold of the wind speed sensor 13 data of the control system 333

[0153] S5: Start the equipment, supply 380V AC power to the fan, and perform tunnel ventilation operation. The ventilation process control principle is as follows Figure 4 There are mainly three situations:

[0154] Case 1: The system is ventilated normally.

[0155] The system operates normally, the temperature of the gas injected into the operating section of shield tunnel 3 meets the requirements (i.e. [T2]≤T≤[T1]), and the wind speed in the operating section is also within the specified range (i.e. [V2]≤V≤[V1]). Construction workers carry out related operations in an orderly and efficient manner in a well-ventilated environment.

[0156] Case 2: The input gas temperature does not meet the requirements.

[0157] During the joint operation of the system, the input gas temperature is not within the specified range (i.e., T>[T1] or T<[T2]), and the control box 9 receives the environmental parameter value that exceeds the set threshold value fed back by the temperature sensor 12, and compares it with the upper threshold value and lower threshold value parameters of the processing sensor data set by the operator: when the input gas temperature is too high (i.e., T>[T1]), the working number of the semiconductor refrigeration plate of the refrigerator 6 is intelligently increased according to the detection result; when the input gas temperature is too low (i.e., T<[T2]), the working number of the semiconductor refrigeration plate of the refrigerator 6 is intelligently reduced according to the detection result.

[0158] Case 3: The wind speed in the operating section does not meet the requirements.

[0159] During the joint operation of the system, when the wind speed in the operating section is not within the specified range (i.e. V>[V1] or V<[V2]), the control box 9 receives the environmental parameter value that exceeds the set threshold value fed back by the wind speed sensor 13, and compares it with the upper threshold value and lower threshold value parameters of the processed sensor data: when the wind speed in the operating section is too large (i.e. V>[V1]), the operating frequency of the secondary fan 5 is intelligently reduced according to the detection result; when the wind speed in the operating section is too small (i.e. V<[V2]), the operating frequency of the secondary fan 5 is intelligently increased according to the detection result.

[0160] This embodiment utilizes a circulating ventilation and cooling system and its working method for the shield tunnel construction operation section, which can achieve multiple gas circulation ventilation inside the shield tunnel and reduce the ambient temperature of the shield construction area from the original 38°C to approximately 29°C, achieving normal ventilation and cooling of the tunnel with low energy consumption, significantly improving the comfort of the construction environment and the construction efficiency of the shield tunnel, and ensuring the smooth advancement of the shield. The above-mentioned construction method is based on an improvement of existing ventilation methods, comprehensively adopting pressure-in and extraction ventilation, while taking into account the cooling and dust removal effects. It can effectively solve the ventilation and cooling problems inside the shield tunnel, and avoid slow shield tunneling due to poor exhaust and excessive temperature in the tunnel.

[0161] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art may make various variations or modifications within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A circulating ventilation and cooling system for the operation section of a shield tunnel construction, characterized in that: include: The air supply system delivers external air to the shield tunnel, achieving primary air supply for the shield tunnel; A secondary air supply system cools the air delivered to the shield tunnel by the air supply system and then compresses the cooled air to the front end of the shield tunnel construction; A control system for controlling the operation of the secondary air supply system to adjust the shield construction environment temperature and the wind speed at the operating end to ensure a comfortable shield construction environment; The exhaust system removes dust from the hot and humid polluted air inside the shield tunnel and discharges the dust-removed polluted air to the outside of the shield tunnel; The air supply system comprises: A main fan is provided at the shield tunnel entrance to provide external air to the shield tunnel; A main air duct is provided at the top of the tunnel segment, one end of the main air duct is connected to the air outlet of the main fan, and the other end of the main air duct extends to the vicinity of the heat source area at the rear of the trolley near the tunnel entrance, and can guide external air into the interior of the shield tunnel; The secondary air supply system comprises: A secondary fan is provided at the rear of the trolley near the tunnel entrance. The secondary fan is a pressure fan that can pressurize the air and increase the air flow rate. A secondary air duct is provided at the top of the tunnel segment. One end of the secondary air duct is flexibly connected to the air outlet of the secondary fan. The other end of the secondary air duct extends to the junction of the trolley and the shield tail near the shield tail, and can guide air to the front end of the tunnel construction face. A cooler is provided at the connection portion between the secondary fan and the secondary air duct, and is used to cool the air output by the secondary air supply system; the cooler adopts a semiconductor cooler, and the semiconductor cooler includes a plurality of semiconductor cooling plates, and the plurality of semiconductor cooling plates are evenly arranged in front of the fan blades of the secondary fan.

2. The shield tunnel construction operation section circulating ventilation and cooling system according to claim 1 is characterized in that: The control system includes: a temperature sensor, the temperature sensor being arranged on the outside of the other end of the secondary air duct and being used to collect the temperature of the air outputted by the secondary air duct; A wind speed sensor is provided on a trolley near the shield tail and is used to measure the wind speed in the operating section after the secondary air supply system inputs air to the front end of the shield tunnel construction; A control box, wherein the input end of the control box is connected to the output end of the temperature sensor and the wind speed sensor, and the output end of the control box is connected to the secondary fan and the refrigerator. The control box can receive and process the received signals in real time and feed back the results, thereby controlling the operation of the secondary fan and the refrigerator.

3. The shield tunnel construction operation section circulating ventilation and cooling system according to claim 1 is characterized in that: The exhaust system comprises: A trolley fan is provided at the head of the trolley near the tunnel entrance, and is used to extract the air inside the shield tunnel and discharge it to the outside of the tunnel, thereby enhancing the air convection inside the shield tunnel; An air outlet pipe is provided at the lower side of the tunnel, one end of the air outlet pipe is connected to the air outlet of the trolley fan, and the other end of the air outlet pipe extends to the tunnel entrance; A dust collector is arranged on a trolley near the tunnel entrance and is located at the connection between the trolley fan and the air outlet pipe, and is used to remove and collect dust from the air inside the shield tunnel extracted by the trolley fan.

4. A construction method for circulating ventilation and cooling in the operating section of a shield tunnel construction, characterized in that: The shield tunnel construction operation section circulating ventilation and cooling system according to any one of claims 1 to 3 is used, and the construction method includes: The air supply system is installed at the entrance of the shield tunnel to transport external air into the shield tunnel, thus achieving primary air supply for the shield tunnel; A secondary air supply system is installed inside the shield tunnel and located in the trolley area at the front end of the tunnel. The secondary air supply system cools the air delivered to the shield tunnel by the air supply system and then compresses the cooled air to the front end of the shield tunnel construction face. The exhaust system is installed inside the shield tunnel and located in the middle of the tunnel. The air outlet of the exhaust system extends to the tunnel entrance. The exhaust system removes dust from the hot and humid polluted air inside the shield tunnel and discharges the dust-removed polluted air to the outside of the shield tunnel. The control system is installed inside the shield tunnel to collect the air temperature output by the secondary air supply system and the wind speed in the shield tunnel construction operation section, and the collected temperature and wind speed data are compared with the temperature setting threshold and the wind speed setting threshold respectively and judged. The operation of the secondary air supply system is controlled according to the judgment result to adjust the shield construction environment temperature and the operating section wind speed to ensure the comfort of the shield construction environment.

5. The construction method for circulating ventilation and cooling in the shield tunnel construction operation section according to claim 4 is characterized in that: Have one or more of the following characteristics: The installation of the air supply system at the shield tunnel entrance includes: installing a main fan of the air supply system at the shield tunnel entrance, fixing a main air duct to the top of the tunnel segment and laying it along the longitudinal direction of the tunnel, connecting one end of the main air duct to the air outlet of the main fan, and extending the other end to the heat source area near the rear of the trolley near the tunnel entrance; The method of installing the secondary air supply system inside a shield tunnel and locating it in the trolley area at the front end of the tunnel includes: installing the secondary air supply system's secondary fan on a trolley near the tunnel entrance; fixing the secondary air duct to the top of the tunnel segment and laying it longitudinally along the tunnel; connecting one end of the secondary air duct to the secondary fan's air outlet and extending the other end to the shield tail, i.e., the front end of the shield tunnel construction; installing a cooler at the connection between the secondary fan and the secondary air duct, and evenly arranging multiple semiconductor cooling chips inside the cooler in front of the blades of the secondary fan; -The exhaust system is installed inside the shield tunnel and located in the middle of the tunnel, including: installing the trolley fan of the exhaust system on a trolley near the tunnel entrance, fixing the air outlet pipe at the lower side of the inside of the shield tunnel and laying it longitudinally along the tunnel, and connecting one end of the air outlet pipe to the air outlet and extending the other end to the tunnel entrance; installing a dust collector at the connection between the trolley fan and the air outlet pipe.

6. The construction method for circulating ventilation and cooling in the shield tunnel construction operation section according to claim 5 is characterized in that: The control system is installed inside the shield tunnel, including: Fixing the temperature sensor on the outside of the air outlet end of the secondary air duct; Fix the wind speed sensor on the trolley near the tail of the shield; The control box is installed in the control room of the trolley near the shield tail, the signal receiving end of the control box is connected to the temperature sensor and the wind speed sensor, and the signal output end is connected to the secondary fan and the refrigerator.

7. The construction method for circulating ventilation and cooling in the shield tunnel construction operation section according to claim 6 is characterized in that: Setting the parameter values ​​of the control system, wherein: Set the upper threshold value [T1] of the temperature sensor data: [T1]=(1-10%)T GB Among them, T GB The upper limit of the construction environment temperature set for the implementation of the standards; Set the lower threshold value [T2] of the temperature sensor data: [T2]=(1+15%)T SF Among them, T SF The temperature that humans feel comfortable in summer is the lower limit of 19℃-24℃. SF =19℃; Set the upper threshold value [V1] of the wind speed sensor data: [V1]=(1-5%)V max Among them, V max The upper limit of wind speed in the construction environment set by the implementation standard; Set the lower threshold value [V2] of the wind speed sensor data: [V2]=max(V T ,V GB ) Among them, V GB The minimum wind speed allowed in the tunnel as specified in the implementation standard; V T The tunnel ventilation meets the cooling requirements, that is, the operating section temperature is the maximum allowable value T max The wind speed at that time, V T The energy conservation equation can be established based on the real-time temperature T of the gas fed into the secondary air duct fed back by the temperature sensor to obtain: c·ρgA(t1+t2)V T ·(T max -T)=κJW(1-η)t1 Where c is the specific heat capacity of the air in the tunnel; ρ is the density of the air in the tunnel; g is the acceleration of gravity; A is the cross-sectional area of ​​the tunnel through which the wind passes; t1 is the time it takes for each shield ring to be driven; t2 is the time it takes for each shield ring to be assembled; T max is the upper limit of the temperature in the tunnel operation section; T is the real-time temperature fed back by the temperature sensor; κ is the correction coefficient considering the actual situation of the tunnel; J is the thermal equivalent, J = 3600 kJ / kWh; W is the total power of the shield machine; η is the total efficiency of the system.

8. The construction method for circulating ventilation and cooling in the shield tunnel construction operation section according to claim 7 is characterized in that: The collected temperature and wind speed data are compared with the temperature setting threshold and the wind speed setting threshold respectively, and a judgment is made. The operation of the secondary air supply system is controlled according to the judgment result, including the following three operating conditions: Case 1: the control system controls the secondary air supply system to ventilate normally; When the temperature of the gas injected into the front end of the shield tunnel construction meets the requirements, that is, [T2]≤T≤[T1]; and the wind speed in the shield tunnel construction operation section is also within the specified range, that is, [V2]≤V≤[V1], the secondary air supply system is controlled to operate normally; Case 2: When the input gas temperature does not meet the requirement, the control system adjusts the working state of the refrigerator; When the input gas temperature is not within the specified range, that is, T>[T1] or T<[T2]: When the input gas temperature is high, that is, T>[T1], the number of working operations of the refrigerator semiconductor refrigeration piece is increased according to the test result; when the input gas temperature is low, that is, T<[T2], the number of working operations of the refrigerator semiconductor refrigeration piece is reduced according to the test result; Case 3: When the wind speed in the operating section does not meet the requirement, the control system adjusts the working state of the secondary fan; When the wind speed in the operating section is not within the specified range, that is, V>[V1] or V<[V2]: when the wind speed in the operating section is too large, that is, V>[V1], the operating frequency of the secondary fan is reduced according to the detection result; when the wind speed in the operating section is too small, that is, V<[V2], the operating frequency of the secondary fan is increased according to the detection result.

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