A construction tunnel flexible air duct anti-bending system and method

Abstract

The present invention belongs to the technical field of construction tunnel ventilation, and in particular, relates to a flexible wind duct anti-bending system and method for construction tunnels, which obtains index parameters in the construction tunnel; calculates the minimum air volume required in the construction tunnel according to the obtained index parameters, and automatically adjusts the fan power according to the calculated minimum air volume; then obtains the friction resistance between the flexible wind duct and the trolley when the trolley moves, and determines whether the friction resistance is greater than the reverse external force of the flexible wind duct. If so, it is offset by a pre-constructed reverse limit control device; finally, the hanging height of the flexible wind duct between the cloth hanging trolley and the lower guide excavation section of the construction tunnel is adjusted according to the anti-bending control device arranged at the end of the cloth hanging trolley close to the face. The present invention can solve the technical problems of serious bending of the flexible wind duct between the secondary lining trolley and the cloth hanging trolley when the secondary lining trolley is moved when the fan in the construction tunnel does not stop blowing, and bending of the flexible wind duct at the end of the cloth hanging trolley close to the face.

Description

Technical Field

[0001] The invention belongs to the technical field of construction tunnel ventilation, and in particular relates to a flexible air duct anti-bending system and method for a construction tunnel. Background Art

[0002] The flexible air ducts of various construction tunnels are often in different degrees of bending in the sections before and after the secondary lining trolley and the cloth hanging trolley. The unevenness of the flexible air duct causes a huge increase in the wind resistance of the inner wall of the air duct, significantly deteriorates the ventilation effect, affects the occupational health of on-site workers, and also wastes electricity resources and increases construction costs; especially for gas tunnels, it also greatly increases the risk of gas accumulation, combustion, and explosion, causing serious safety hazards or causing production safety accidents.

[0003] Through years of on-site investigation and research, it was found that the bending phenomenon of the flexible wind duct in the construction tunnel is usually caused by the fact that the fan is in a non-stop state, which makes the flexible wind duct have a certain elastic expansion and strength in the ventilation state. Therefore, the friction resistance between the flexible wind duct and the secondary lining trolley and the cloth hanging trolley in the ventilation state is large, and when the secondary lining trolley is moved, the flexible wind duct also moves a certain distance, which eventually causes the front and rear ends of the cloth hanging trolley to be in a serious bending state.

[0004] In summary, from the perspectives of safe production, energy conservation and environmental protection, and occupational health, solving the problem of preventing bending of flexible air ducts in construction tunnels is a very important and urgently needed key construction technology for construction tunnels, especially gas tunnels. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a system and method for preventing the bending of the flexible wind duct in a construction tunnel, so as to solve the technical problems that when the secondary lining trolley is moved without stopping the wind blower in the construction tunnel, the flexible wind duct between the secondary lining trolley and the cloth hanging trolley is severely bent, and the flexible wind duct at the end of the cloth hanging trolley close to the heading face is bent.

[0006] The basic solution provided by the present invention is a flexible wind tube anti-bending system for a construction tunnel, comprising:

[0007] Data acquisition module: used to obtain index parameters in the construction tunnel;

[0008] Flexible air duct air volume matching module: used to calculate the minimum air volume required in the construction tunnel according to the obtained index parameters, and automatically adjust the fan power according to the calculated minimum air volume;

[0009] Flexible air duct reverse limit control module: used to obtain the friction resistance between the flexible air duct and the secondary lining trolley when the secondary lining trolley moves. When the friction resistance is less than the reverse external force of the flexible air duct, a complete sliding occurs between the flexible air duct and the secondary lining trolley. Then, based on the minimum air volume required in the construction tunnel, the automatic movement switch of the secondary lining trolley is turned on to determine whether a complete sliding occurs between the flexible air duct and the secondary lining trolley. If so, the reverse limit control device is not started, otherwise, the reverse limit control device is started;

[0010] Anti-bending control module: The hanging height of the flexible air duct between the cloth hanging trolley and the lower excavation section of the construction tunnel is adjusted according to the anti-bending control device arranged at the end of the cloth hanging trolley close to the heading face.

[0011] Furthermore, the data acquisition module includes a data acquisition unit and a fresh air conversion unit. The data acquisition unit is used to collect index data of the construction tunnel site in real time. The fresh air conversion unit is used to obtain the fresh air demand standard during the tunnel construction process in the tunnel construction technical specifications and generate a fresh air conversion table.

[0012] Furthermore, the flexible duct air volume matching module includes an air volume matching unit and an air duct fan control unit. The air volume matching unit matches the environmental data collected by the data acquisition unit with the fresh air conversion table to convert and generate the minimum air volume required for the construction tunnel; the air duct fan control unit is used to generate a control command according to the minimum air volume to control the fan power in the construction tunnel to provide the minimum air volume.

[0013] Further, in the flexible wind tube reverse limit control module, the friction resistance between the flexible wind tube and the secondary lining trolley when the secondary lining trolley moves is obtained, and it is determined whether a complete sliding occurs between the flexible wind tube and the secondary lining trolley. Specifically:

[0014] Obtain parameter data of the flexible air duct through-holes opened on the secondary lining trolley;

[0015] The maximum friction resistance of the flexible air duct in the hole through which the air duct passes is calculated based on the obtained parameter data. The calculation formula is:

[0016] f s =f all ×μ

[0017] f all =f up +f down +f left +f right

[0018] Among them, f allrepresents the normal outward pressure of the flexible air duct, μ represents the sliding friction resistance coefficient corresponding to the flexible air duct passing through the inner wall of the hole of the secondary lining trolley, and f up Indicates the upward pressure of the flexible air duct, f down Indicates the downward pressure of the flexible air duct, f left Indicates the leftward pressure of the flexible air duct, f right Indicates the rightward pressure of the flexible air cylinder;

[0019] When the power of the tunnel fan reaches the minimum required air volume during the automatic frequency conversion construction, the flexible air duct and the secondary lining trolley will completely slide when the automatic movement switch of the secondary lining trolley is turned on, and the reverse limit control device between the holes where the flexible air duct passes will not be called to provide external force f c ; When the power of the tunnel fan is at the minimum required air volume during the automatic frequency conversion construction, the flexible air duct and the secondary lining trolley do not slide completely when the automatic movement switch of the secondary lining trolley is turned on, the reverse limit control device of the flexible air duct between the holes through which the air duct passes is called to provide external force f c , until complete sliding occurs.

[0020] Furthermore, the reverse limit control device includes a plurality of arc locking rings, a fixed cable and a connecting piece. The plurality of arc locking rings are spliced ​​together by connecting pieces and fixed to the outer wall of the flexible wind tube. A fixing buckle is provided on the arc locking ring. One end of the fixing cable is fixedly connected to the fixing buckle, and the other end is fixed by a connecting piece.

[0021] Furthermore, the anti-bending control device in the anti-bending control module includes an expansion screw, a hook fixing, a hook adjustable height part, and a hook. The front end of the expansion screw is fixed to the construction tunnel wall, and the rear end is provided with a ring; the hook fixing is fixed to the ring at the rear end of the expansion screw, and the hook fixing is vertically provided with a plurality of screw holes. The hook adjustable height part is installed on the screw hole of the hook fixing, and the hook is fixed to the bottom end of the hook adjustable height part.

[0022] A method for preventing bending of a flexible air duct in a construction tunnel, applied to the above-mentioned system for preventing bending of a flexible air duct in a construction tunnel, comprises:

[0023] S1: Obtain index parameters in the construction tunnel;

[0024] S2: Calculate the minimum air volume required in the construction tunnel according to the obtained index parameters, and automatically adjust the fan power according to the calculated minimum air volume;

[0025] S3: Obtain the friction resistance between the flexible wind tube and the secondary lining trolley when the secondary lining trolley moves. When the friction resistance is less than the reverse external force of the flexible wind tube, a complete sliding occurs between the flexible wind tube and the secondary lining trolley. Then, based on the minimum air volume required in the construction tunnel, turn on the automatic movement switch of the secondary lining trolley to determine whether a complete sliding occurs between the flexible wind tube and the secondary lining trolley. If so, do not start the reverse limit control device. Otherwise, start the reverse limit control device.

[0026] S4: The hanging height of the flexible air duct between the cloth hanging trolley and the lower guide excavation section of the construction tunnel is adjusted according to the anti-bending control device arranged at the end of the cloth hanging trolley close to the heading face.

[0027] The principle and advantage of the present invention are that when the flexible air duct in the construction tunnel of the present application passes through the air duct reserved by the secondary lining trolley and the holes on the cloth hanging trolley, the secondary lining trolley moves under ventilation conditions, causing the flexible air duct between the secondary lining trolley and the cloth hanging trolley and at the end of the cloth hanging trolley close to the heading face to bend, resulting in a sharp increase in the air duct resistance of the flexible air duct, a large wind loss, a waste of electricity resources, and a poor ventilation effect. In this regard, this scheme calculates the minimum air volume when the secondary lining trolley moves through wind speed sensors, pressure sensors and the fresh air conversion table specified in relevant technical specifications, and then calculates the average wind speed value according to the air duct outlet corresponding to the minimum air volume, and the air duct fan control unit controls the air duct fan to automatically change the frequency to the corresponding minimum air volume; in this case, if the flexible air duct still moves with the secondary lining trolley, an external force is applied through the reverse limit control device to cause sliding friction between the flexible air duct and the secondary lining trolley, and finally the flexible air duct does not move with the secondary lining trolley when it moves, so as to ensure that the flexible air duct between the secondary lining trolley and the cloth hanging trolley is smooth and without twists.

[0028] In addition, an anti-bending control device is set at the end of the cloth hanging trolley close to the face. This device solves the problem of bending of the flexible air duct due to inconsistent hanging heights at the end of the cloth hanging trolley close to the face. This technology can ensure that the flexible air duct does not move with the movement of the secondary lining trolley in the construction tunnel, and ensures that the flexible air duct between the secondary lining trolley and the cloth hanging trolley, and the flexible air duct at the end of the cloth hanging trolley close to the face do not bend. At the same time, it also ensures that the construction tunnel, especially the safe construction of the gas tunnel, and the outstanding technical risks such as occupational health have been completely resolved, and it also saves electricity resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a functional block diagram of an embodiment of the present invention;

[0030] Figure 2 is a logic block diagram of an embodiment of the present invention;

[0031] Figure 3It is a schematic diagram of the bending of the flexible air duct between the secondary lining trolley and the cloth hanging trolley of the construction tunnel referred to in the present invention;

[0032] Figure 4 It is a schematic diagram of the bending of the flexible air duct at one end of the tunnel cloth hanging trolley of the construction tunnel referred to in the present invention;

[0033] Figure 5 A logic block diagram of completely sliding between the flexible air cylinder and the secondary lining trolley according to an embodiment of the present invention;

[0034] Figure 6 This is a force analysis diagram of the flexible air duct in an embodiment of the present invention;

[0035] Figure 7 It is a schematic diagram of the arrangement of the wind speed sensor at the air duct outlet and the pressure sensor on the inner wall of the hole through which the air duct of the secondary lining trolley passes in the embodiment of the present invention;

[0036] Figure 8 It is a schematic diagram of the structure of the reverse limit control device of the flexible air duct in an embodiment of the present invention;

[0037] Fig. 9 This is a schematic diagram of the structure of an anti-bending control device in an embodiment of the present invention;

[0038] Fig.10 The figure is a flowchart of an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following is further described in detail through specific implementation methods:

[0040] The marks in the drawings of the specification include: arc locking ring 1, connecting part 2, fixing buckle 3, middle pull rope 4, end pull rope 5, expansion screw 6, expansion screw 7, ring 701, hook fixing part 8, screw hole 801, hook adjustable height part 9, hook 10.

[0041] The embodiment is basically as follows Figure 1 and Figure 2 As shown: A flexible wind duct anti-bending system for a construction tunnel, comprising a data acquisition module, a flexible wind duct air volume matching module, a flexible wind duct reverse limit control module and an anti-bending control module, wherein:

[0042] The data acquisition module is used to obtain index parameters in the construction tunnel; in the present embodiment, the index parameters refer to the parameters of various indicators related to safety, occupational health, etc. in the construction tunnel. Specifically, the data acquisition module includes a data acquisition unit and a fresh air conversion unit. Specifically, the parameters of various indicators in the construction tunnel acquired by the data acquisition unit include the diameter of the wind duct, the average wind speed at the wind duct outlet at the face end, the average number of workers in the tunnel, the gas concentration in the airflow in the tunnel, the average temperature in the tunnel, and other parameters related to safety and occupational health. The fresh air conversion unit obtains the fresh air demand standard during tunnel construction in the tunnel construction technical specifications and generates a fresh air conversion table.

[0043] Among the existing technical standards, there are mature current tunnel construction technical specifications and gas tunnel construction technical specifications. In these specifications, the required amount of fresh air is recorded. For example, tunnel workers need 4m per minute. 2 Fresh air; the fresh air required by the internal combustion engines can also be obtained according to the number and power of the internal combustion engines; the dilution of harmful gases such as gas also requires sufficient fresh air to ensure on-site construction safety. Therefore, under these specifications, a fresh air conversion table required for each equipment, each operator, and harmful gas dilution in the construction tunnel can be obtained.

[0044] The index parameters collected above are matched with the fresh air conversion table and transmitted to the flexible duct air volume matching module for subsequent operations.

[0045] The flexible duct air volume matching module is used to calculate the minimum air volume required in the construction tunnel according to the acquired index parameters, and automatically adjust the fan power according to the calculated minimum air volume; specifically, the flexible duct air volume matching module includes an air volume matching unit and a duct fan control unit, and the air volume matching unit matches the environmental data collected by the data acquisition unit with the fresh air conversion table to convert and generate the minimum air volume required for the construction tunnel; the duct fan control unit is used to generate a control command according to the minimum air volume to control the fan power in the construction tunnel to provide the minimum air volume.

[0046] This can be used to calculate the minimum air volume required in the target construction tunnel. After the minimum air volume result is obtained, the power of the construction tunnel fan can be adjusted to achieve the operation of the wind duct in the construction tunnel with the minimum air volume. Specifically, Figure 5 As shown in the figure, the minimum air volume when the secondary lining trolley moves, that is, the optimal required air volume Q 优 =Max(Q 人 , Q 机 , Q 烷 , …), assuming that the cross-sectional size of the air duct outlet is A, based on Q 优 The average wind speed V required at the air duct outlet can be calculated by mean =Q优 / A, based on this, the fan automatically changes frequency to adjust the wind speed at the air outlet of the air duct to V mean , where V mean How to obtain it is to place a wind speed sensor 0-1m outside the flexible air duct outlet for testing. The specific placement position is as follows: Figure 7 The dotted circle with a radius of 1 / 2 of the circular section facing the air outlet of the air duct as shown can be used.

[0047] Under the minimum air volume state, it is necessary to obtain the friction resistance of the flexible air duct in the tunnel on the secondary lining trolley. The present application is implemented by a flexible air duct reverse limit control module. Specifically, the flexible air duct reverse limit control module is used to obtain the friction resistance between the flexible air duct and the secondary lining trolley when the secondary lining trolley moves. When the friction resistance is less than the reverse external force of the flexible air duct, a complete sliding occurs between the flexible air duct and the secondary lining trolley. Then, based on the minimum air volume required in the construction tunnel, the automatic movement switch of the secondary lining trolley is turned on to determine whether a complete sliding occurs between the flexible air duct and the secondary lining trolley. If so, the reverse limit control device is not started, otherwise the reverse limit control device is started;

[0048] In this embodiment, the process of the flexible air duct reverse limit control module obtaining the friction resistance between the air duct and the secondary lining trolley when the secondary lining trolley moves is:

[0049] Step 1: Obtain parameter data of the flexible air duct through-holes opened on the secondary lining trolley; in this application, 5 air duct through-holes are generally designed on the secondary lining trolley, and the reserved thickness of the air duct through-holes is 20-40cm. In this regard, in order to facilitate the force analysis, it is simplified into a secondary lining trolley through-hole and a flexible air duct with a longer length. Because the inner wall of the flexible air duct is subjected to normal outward pressure when the flexible air duct is ventilated, after ignoring the mass of the airflow itself, the normal outward pressure in each direction on the flexible air duct through-hole on the secondary lining trolley is equivalent, so the friction force and the friction coefficient are also equivalent; in order to solve practical problems in the subsequent classification and working conditions, the normal outward pressure on the inner wall of the secondary lining trolley through-hole in each direction is integrated and simplified into upward f up , downf down , Left left , right right , see Figure 6 As shown;

[0050] Step 2: Obtain the corresponding sliding friction resistance coefficient μ, which can be obtained through physical simulation tests of the flexible air duct and the inner wall material of the cavity and the roughness of the friction surface, or by referring to relevant materials.

[0051] Step 3: Because the friction coefficient of the inner wall of the secondary lining trolley wind tube passage hole corresponding to the normal outward pressure of the flexible wind tube in the four directions is the same, the maximum friction resistance of the flexible wind tube in the wind tube passage hole is calculated based on the obtained parameter data. The calculation formula is:

[0052] f s =f all ×μ

[0053] f all =f up +f down +f left +f right

[0054] Among them, f all represents the normal outward pressure of the flexible air duct, μ represents the sliding friction resistance coefficient corresponding to the flexible air duct passing through the inner wall of the hole of the secondary lining trolley, and f up Indicates the upward pressure of the flexible air duct, f down Indicates the downward pressure of the flexible air duct, f left Indicates the leftward pressure of the flexible air duct, f right Indicates the rightward pressure of the flexible air duct; f up 、f down 、f left 、f right The pressure sensors are arranged on the inner wall of the reserved air duct through the hole of the secondary lining trolley in this application. The specific arrangement is as follows Figure 7 As shown in the right sub-figure, there are four pressure sensors, which are arranged on the inner wall of the hole where the secondary lining trolley air duct passes through the 1 / 4 arc in the upper, lower, left and right directions.

[0055] Step 4: When the power of the tunnel fan reaches the minimum required air volume during the automatic frequency conversion construction, the automatic movement switch of the secondary lining trolley is turned on, and the flexible air duct and the secondary lining trolley completely slide, and the reverse limit control device between the holes where the flexible air duct passes through is not called to provide external force f c ; When the power of the tunnel fan is at the minimum required air volume during the automatic frequency conversion construction, the flexible air duct and the secondary lining trolley do not slide completely when the automatic movement switch of the secondary lining trolley is turned on, the reverse limit control device of the flexible air duct between the holes through which the air duct passes is called to provide external force f c , until complete sliding occurs.

[0056] In the implementation process of the above steps three and four, when the flexible wind duct in the construction tunnel turns on the automatic movement switch of the secondary lining trolley under the lowest air volume state and the flexible wind duct and the secondary lining trolley do not slide completely, an additional reverse external force is required to make them slide completely, so that the sliding occurs and the flexible wind duct does not move with the secondary lining trolley. For this purpose, the present application is implemented by a reverse limit control device, specifically, as Figure 8 As shown, the reverse limit control device includes a plurality of arc locking rings 1, a fixed cable and a connector 2. The plurality of arc locking rings 1 are spliced ​​together by the connector 2 and fixed to the outer wall of the flexible wind tube. A fixing buckle 3 is provided on the arc locking ring 1. One end of the fixing cable is fixedly connected to the fixing buckle 3, and the other end is fixed by the connector 2.

[0057] The implementation principle of the above-mentioned reverse limit control device is that based on the elastic expansion of the outer wall of the flexible wind tube in the normal direction, the flexible wind tube is fixed by the arc locking ring 1 and the fixed cable, thereby generating a reverse external pulling force so that the flexible wind tube does not move with the secondary lining trolley, wherein the ratio of the theoretical diameter of the flexible wind tube to the diameter of the arc locking ring 1 is the locking ratio, and the larger the locking ratio, the better the locking effect. In the present application, the reverse limit control device includes 4 1 / 4 arc locking rings 1, and the 4 arc locking rings 1 are connected to each other through the connecting piece 2 nut and nut, and the middle section of the 4 arc locking rings 1 is provided with a fixing buckle 3, and the fixing cable includes an intermediate pull rope 4 with adjustable length and two end pull ropes 5, and the two ends of the intermediate pull rope 4 are connected to the fixing buckles 3, one end of the end pull rope 5 is connected to the intermediate pull rope 4, and the other end is fixed to the inner wall of the wind tube through the hole through the expansion screw 6.

[0058] Through the above-mentioned flexible wind tube reverse limit control module, it can effectively ensure the sliding of the flexible wind tube in the hole through which the wind tube passes, and avoid bending. However, for the end of the cloth hanging trolley close to the palm face, the flexible wind tube will still be severely bent due to the inconsistency between the height of the wind tube on the cloth hanging trolley and the hanging height of the lower guide excavation section or the sudden change in height. In view of this, the present application arranges an anti-bending control module at the end of the cloth hanging trolley close to the palm face, and adjusts the hanging height of the cloth hanging trolley and the lower guide excavation section of the construction tunnel according to the anti-bending control device arranged at the end of the cloth hanging trolley close to the palm face; specifically, the anti-bending control device in the anti-bending control module in the present application is as follows Fig. 9 As shown, it includes an expansion screw 7, a hook fixing part 8, a hook adjustable height part 9, and a hook 10. The front end of the expansion screw 7 is fixed to the construction tunnel wall, and the rear end is provided with a ring 701; the hook fixing part 8 is fixed to the ring 701 at the rear end of the expansion screw 7, and the hook fixing part 8 is vertically provided with a plurality of screw holes 801. The hook adjustable height part 9 is installed on the screw holes 801 of the hook fixing part 8, and the hook 10 is fixed to the bottom end of the hook adjustable height part 9.

[0059] In this regard, Figure 3 and Figure 4 As shown, when the flexible air duct in the construction tunnel of the present application passes through the air duct reserved by the secondary lining trolley and the holes on the cloth hanging trolley, the secondary lining trolley moves under ventilation conditions, causing the flexible air duct between the secondary lining trolley and the cloth hanging trolley and at the end of the cloth hanging trolley close to the heading face to bend, resulting in a huge increase in the air duct resistance of the flexible air duct, a large wind loss, a waste of electricity resources, and a significant deterioration in the ventilation effect. In this regard, this scheme calculates the minimum air volume when the secondary lining trolley moves through wind speed sensors, pressure sensors and the fresh air conversion table specified in relevant technical specifications, and then calculates the average wind speed value according to the air duct outlet corresponding to the minimum air volume, and the air duct fan control unit controls the air duct fan to automatically change the frequency to the corresponding minimum air volume; in this case, if the flexible air duct still moves with the secondary lining trolley, an external force is applied through the reverse limit control device to cause sliding friction between the flexible air duct and the secondary lining trolley, and finally the flexible air duct does not move with the secondary lining trolley when it moves, so as to ensure that the flexible air duct between the secondary lining trolley and the cloth hanging trolley is smooth and without twists.

[0060] In addition, an anti-bending control device is set at the end of the cloth hanging trolley close to the face. This device solves the problem of bending of the flexible air duct caused by inconsistent hanging heights at the end of the cloth hanging trolley close to the face. This technology can ensure that the flexible air duct does not move with the movement of the secondary lining trolley in the construction tunnel, and ensures that the flexible air duct between the secondary lining trolley and the cloth hanging trolley, and the flexible air duct at the end of the cloth hanging trolley close to the face do not bend. At the same time, it also ensures that the construction of tunnels, especially the safe construction of gas tunnels, and the outstanding technical risks such as occupational health are completely resolved, and it also saves electricity resources.

[0061] like Fig.10 As shown, in another embodiment of the present embodiment, a method for preventing bending of a flexible wind duct in a construction tunnel is also included, which is applied to the above-mentioned system for preventing bending of a flexible wind duct in a construction tunnel, including:

[0062] S1: Obtain index parameters in the construction tunnel;

[0063] S2: Calculate the minimum air volume required in the construction tunnel according to the obtained index parameters, and automatically adjust the fan power according to the calculated minimum air volume;

[0064] S3: Obtain the friction resistance between the flexible wind tube and the secondary lining trolley when the secondary lining trolley moves. When the friction resistance is less than the reverse external force of the flexible wind tube, a complete sliding occurs between the flexible wind tube and the secondary lining trolley. Then, based on the minimum air volume required in the construction tunnel, turn on the automatic movement switch of the secondary lining trolley to determine whether a complete sliding occurs between the flexible wind tube and the secondary lining trolley. If so, do not start the reverse limit control device. Otherwise, start the reverse limit control device.

[0065] S4: The hanging height of the flexible air duct between the cloth hanging trolley and the lower guide excavation section of the construction tunnel is adjusted according to the anti-bending control device arranged at the end of the cloth hanging trolley close to the heading face.

[0066] The above are only embodiments of the present invention. Common knowledge such as the known specific structures and characteristics in the scheme is not described in detail here. Ordinary technicians in the relevant field are aware of all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply conventional experimental means before that date. Ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A flexible air duct anti-bending system for a construction tunnel, characterized by: include: Data acquisition module: used to obtain index parameters in the construction tunnel; Flexible air duct air volume matching module: used to calculate the minimum air volume required in the construction tunnel according to the obtained index parameters, and automatically adjust the fan power according to the calculated minimum air volume; Flexible air duct reverse limit control module: based on the minimum air volume required in the construction tunnel, the secondary lining trolley automatic movement switch is turned on, and the friction resistance between the flexible air duct and the secondary lining trolley when the secondary lining trolley moves is obtained through the flexible air duct reverse limit control module, and it is judged whether a complete sliding occurs between the flexible air duct and the secondary lining trolley. If so, the reverse limit control device is not started, otherwise the reverse limit control device is started; the judgment condition for the complete sliding is: when the friction resistance is less than the reverse external force of the flexible air duct, the flexible air duct and the secondary lining trolley are completely slid; In the flexible wind tube reverse limit control module, the friction resistance between the flexible wind tube and the secondary lining trolley when the secondary lining trolley moves is obtained, and whether a complete sliding occurs between the flexible wind tube and the secondary lining trolley is determined as follows: Obtain parameter data of the flexible air duct through-holes opened on the secondary lining trolley; The maximum friction resistance of the flexible air duct in the hole through which the air duct passes is calculated based on the obtained parameter data. The calculation formula is: in, It indicates the maximum friction resistance of the flexible air duct when it passes through the hole. represents the normal outward pressure of the flexible air duct, μ represents the sliding friction resistance coefficient corresponding to the flexible air duct passing through the inner wall of the hole of the secondary lining trolley, Indicates the upward pressure of the flexible air duct. Indicates the downward pressure of the flexible air duct. Indicates the left pressure of the flexible air duct. Indicates the rightward pressure of the flexible air cylinder; When the fan power of the tunnel is at the minimum air volume during the automatic frequency conversion construction, the flexible air duct and the secondary lining trolley will completely slide when the automatic movement switch of the secondary lining trolley is turned on, and the reverse limit control device between the holes where the flexible air duct passes through will not be used to provide external force. When the fan power of the tunnel is at the minimum air volume during the automatic frequency conversion construction, the flexible air duct and the secondary lining trolley do not slide completely when the automatic movement switch of the secondary lining trolley is turned on. Then the reverse limit control device of the flexible air duct between the holes through which the air duct passes is called to provide external force. , until complete sliding occurs; Anti-bending control module: The hanging height of the flexible air duct between the cloth hanging trolley and the lower excavation section of the construction tunnel is adjusted according to the anti-bending control device arranged at the end of the cloth hanging trolley close to the heading face.

2. The construction tunnel flexible air duct anti-bending system according to claim 1 is characterized by: The data acquisition module includes a data acquisition unit and a fresh air conversion unit. The data acquisition unit is used to collect index data of the construction tunnel site in real time. The fresh air conversion unit is used to obtain the fresh air demand standard during the tunnel construction process in the tunnel construction technical specifications and generate a fresh air conversion table.

3. The construction tunnel flexible air duct anti-bending system according to claim 2 is characterized by: The flexible duct air volume matching module includes an air volume matching unit and a duct fan control unit. The air volume matching unit matches the environmental data collected by the data acquisition unit with the fresh air conversion table to convert and generate the minimum air volume required for the construction tunnel; the duct fan control unit is used to generate a control command according to the minimum air volume to control the fan power in the construction tunnel to provide the minimum air volume.

4. The construction tunnel flexible air duct anti-bending system according to claim 1 is characterized by: The reverse limit control device includes a plurality of arc locking rings, a fixed cable and a connecting piece. The plurality of arc locking rings are spliced ​​together by connecting pieces and fixed to the outer wall of the flexible air duct. A fixing buckle is provided on the arc locking ring. One end of the fixing cable is fixedly connected to the fixing buckle, and the other end is fixed by the connecting piece.

5. The construction tunnel flexible air duct anti-bending system according to claim 4 is characterized by: The anti-bending control device in the anti-bending control module includes an expansion screw, a hook fixing, a hook adjustable height part, and a hook. The front end of the expansion screw is fixed to the construction tunnel wall, and the rear end is provided with a ring; the hook fixing is fixed to the ring at the rear end of the expansion screw, and the hook fixing is vertically provided with a plurality of screw holes. The hook adjustable height part is installed on the screw holes of the hook fixing part, and the hook is fixed to the bottom end of the hook adjustable height part.

6. A method for preventing bending of a flexible air duct in a construction tunnel, applied to a system for preventing bending of a flexible air duct in a construction tunnel as claimed in any one of claims 1 to 5, characterized in that: include: S1: Obtain index parameters in the construction tunnel; S2: Calculate the minimum air volume required in the construction tunnel according to the obtained index parameters, and automatically adjust the fan power according to the calculated minimum air volume; S3: Based on the minimum air volume required in the construction tunnel, the automatic movement switch of the secondary lining trolley is turned on, and the friction resistance between the flexible wind duct and the secondary lining trolley when the secondary lining trolley moves is obtained through the flexible wind duct reverse limit control module, and it is judged whether a complete sliding occurs between the flexible wind duct and the secondary lining trolley. If so, the reverse limit control device is not started, otherwise the reverse limit control device is started; the judgment condition for the complete sliding is: when the friction resistance is less than the reverse external force of the flexible wind duct, a complete sliding occurs between the flexible wind duct and the secondary lining trolley; specifically: Obtain parameter data of the flexible air duct through-holes opened on the secondary lining trolley; The maximum friction resistance of the flexible air duct in the hole through which the air duct passes is calculated based on the obtained parameter data. The calculation formula is: in, It indicates the maximum friction resistance of the flexible air duct when it passes through the hole. represents the normal outward pressure of the flexible air duct, μ represents the sliding friction resistance coefficient corresponding to the flexible air duct passing through the inner wall of the hole of the secondary lining trolley, Indicates the upward pressure of the flexible air duct. Indicates the downward pressure of the flexible air duct. Indicates the left pressure of the flexible air duct. Indicates the rightward pressure of the flexible air cylinder; When the fan power of the tunnel is at the minimum air volume during the automatic frequency conversion construction, the flexible air duct and the secondary lining trolley will completely slide when the automatic movement switch of the secondary lining trolley is turned on, and the reverse limit control device between the holes where the flexible air duct passes through will not be used to provide external force. When the fan power of the tunnel is at the minimum air volume during the automatic frequency conversion construction, the flexible air duct and the secondary lining trolley do not slide completely when the automatic movement switch of the secondary lining trolley is turned on. Then the reverse limit control device of the flexible air duct between the holes through which the air duct passes is called to provide external force. , until complete sliding occurs; S4: The hanging height of the flexible air duct between the cloth hanging trolley and the lower guide excavation section of the construction tunnel is adjusted according to the anti-bending control device arranged at the end of the cloth hanging trolley close to the heading face.

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