An experimental device and test method for simulating low vacuum transport pipe network structure

Abstract

The present invention discloses an experimental device and test method for simulating a low vacuum transport pipe network structure, including an assembled low vacuum flexible pipe, a temperature control system, a particle release instrument, a vacuum control system, an infrared thermal imager and a 3D3C PIV system, which are used to monitor the position and change state of the inductive particles inside the assembled low vacuum flexible pipe; a data receiving terminal, which is used to receive and analyze the data of the temperature control system, the particle release instrument, the infrared thermal imager and the 3D3C PIV system, judge the data changes of the stress, temperature and air pressure inside the assembled low vacuum flexible pipe, and determine the sealing effect of the assembled low vacuum flexible pipe. The present invention has the ability to stretch and bend, effectively ensures the airtightness of the low vacuum tunnel structure, and can improve the ability of the tunnel structure to adapt to different deformations caused by temperature, pressure, etc.

Description

Technical Field

[0001] The invention relates to an experimental device and a test method for simulating a low vacuum transport pipe network structure. Background Art

[0002] With the rapid development of social economy, the low vacuum pipeline transportation system is a new type of transportation system. The running speed of the magnetic levitation train inside the pipeline can reach 600-1000 km / h, which greatly shortens the communication time between cities. The air pressure inside the pipeline is reduced to one thousandth of the atmospheric pressure, making it in a low vacuum state, thereby reducing the air resistance encountered during the operation of the train, thereby increasing the speed of the train. Due to the reduction of air resistance, the energy loss caused by air resistance will be greatly reduced, which has a significant effect of energy saving and consumption reduction; in addition, since the transportation pipeline is continuous and the space is closed, it is less affected by natural conditions, air noise is reduced, and the stability and comfort of the train during operation will be increased.

[0003] In the continuous optimization of the design of low vacuum pipe network projects, the state and mechanical properties of low vacuum pipelines as the main operating entity play a vital role in the reliable and safe operation of the vacuum system, so it is necessary to carry out targeted research. The tunnel-type pipeline structure can save and efficiently utilize land resources. On the premise of meeting the use requirements, the existing assembled pipe segment structure can save pipeline construction costs and has obvious economic benefits. However, the sealing performance and mechanical behavior of the assembled tunnel pipe segment structure in the complex low vacuum environment need to be explored experimentally.

[0004] After the gas is extracted to form a vacuum state, negative pressure is formed inside the pipeline. Under the action of atmospheric pressure, external gas tends to penetrate and diffuse into the interior of the pipeline. Therefore, the sealing performance of the pipeline structure must meet the engineering sealing requirements; when there is a water environment around the low-vacuum tunnel pipeline, the vacuum negative pressure will further aggravate the penetration of groundwater into the pipe joints. Therefore, the water permeability and water tightness of the low-vacuum negative pressure tunnel still need to be explored and experimental verification is required; in a low-vacuum environment, the internal structure of the tunnel pipe joint is under the action of negative pressure, and the mechanical properties and damage of the pipe joint structure and joints cannot be ignored; the internal temperature of the low-vacuum tunnel structure will be significantly increased due to factors such as the environment and the high-speed travel of trains. The changes in the mechanical properties of the tunnel structure at different temperatures also need to be further verified and explored. Summary of the invention

[0005] The purpose of the present invention is to provide a technical solution of an experimental device and a test method for simulating a low-vacuum transport pipeline network structure in response to the deficiencies in the prior art. The present invention has certain stretching and bending capabilities, which can effectively ensure the airtightness of the low-vacuum tunnel structure while improving the tunnel structure's ability to adapt to different deformations caused by temperature, pressure, etc. At the same time, under the special working conditions of a large-scale low-vacuum pipeline network structure in an actual low-vacuum environment, a comprehensive simulation of the actual environment of the low-vacuum tunnel pipeline network structure can be achieved, and the airtightness and structural mechanical properties of the pipeline network structure under the low-vacuum transport environment can be verified.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] An experimental device for simulating a low vacuum transport pipe network structure, characterized in that it includes:

[0008] An assembled low vacuum flexible pipeline, comprising a sealed pipe segment structure and a corrugated flexible pipe segment structure arranged at intervals;

[0009] A temperature control system, used for detecting and controlling the temperature of the sealed pipe joint structure and the corrugated flexible pipe joint structure;

[0010] a particle release instrument for releasing induction particles to the sealed pipe segment structure and the corrugated flexible pipe segment structure;

[0011] A vacuum control system for adjusting the vacuum degree inside the assembled low-vacuum flexible pipeline;

[0012] An infrared thermal imager and a 3D3C PIV system, which are distributed on both sides of the assembled low-vacuum flexible pipeline and are used to monitor the position and change state of the sensing particles inside the assembled low-vacuum flexible pipeline;

[0013] and a data receiving terminal for receiving and analyzing data from the temperature control system, the particle release instrument, the infrared thermal imager and the 3D3C PIV system, judging the data changes of the internal stress, temperature and air pressure of the assembled low vacuum flexible pipeline, and determining the sealing effect of the assembled low vacuum flexible pipeline.

[0014] The experimental device formed by the above structure has a certain stretching and bending ability, which can effectively ensure the airtightness of the low-vacuum tunnel structure, and at the same time improve the ability of the tunnel structure to adapt to different deformations caused by temperature, pressure, etc. At the same time, under the special working conditions of the large-scale low-vacuum pipeline network structure in the actual low-vacuum environment, it can realize a comprehensive simulation of the actual environment of the low-vacuum tunnel pipeline network structure, and can verify the airtightness and structural mechanical properties of the pipeline network structure in the low-vacuum transportation environment.

[0015] Furthermore, the sealed pipe segment structure includes a concrete base plate and a rigid pipe body. The rigid pipe body is a semicircular ring structure. The arch foot position of the rigid pipe body is provided with an arch foot steel plate extending horizontally outward. Embedded steel plates are symmetrically provided on both sides of the concrete base plate. The arch foot steel plate and the embedded steel plate are aligned with each other and fixedly connected by flange splicing bolts. The concrete base plate is provided with flange splicing bolts. Through the structural design of the rigid pipe body, it can be fully fitted to the inner wall of the tunnel structure, thereby improving the stability and reliability of the sealed pipe segment structure.

[0016] Furthermore, the wavy flexible pipe segment structure includes a flexible pipe segment and a rear-welded base plate. The flexible pipe segment has a wavy structure. The outer side of the flexible pipe segment is provided with a wavy pipe pattern. The arch foot position of the flexible pipe segment is provided with an arch foot steel plate extending horizontally outward. The outer side of the rear-welded base plate is provided with an embedded steel plate. The arch foot steel plate and the embedded steel plate are aligned with each other and fixedly connected by flange splicing bolts. The rear-welded base plate is provided with flange splicing bolts. A load control system is provided at the bottom of the wavy flexible pipe segment structure. By changing the size of the wavelength, the flexible pipe segment has greater tensile and bending properties, so that the form of the flexible pipe segment can be adjusted to adapt to changes in load. The load here refers to displacement.

[0017] Furthermore, sealing doors are provided at both ends of the assembled low-vacuum flexible pipeline, and the sealing doors are connected by flange splicing bolts. The sealing doors are provided with exhaust valves, particle release valves and data wiring valves. The exhaust valve is electrically connected to the vacuum control system, the particle release valve is electrically connected to the particle release instrument, and the data wiring valve is electrically connected to the data receiving terminal.

[0018] Furthermore, extension steel plates are provided at the positions where the rigid pipe body and the flexible pipe joint contact each other, and two adjacent extension steel plates are fixedly connected by flange splicing bolts, thereby improving the connection stability and reliability between the rigid pipe body and the flexible pipe joint.

[0019] Furthermore, the embedded steel plate, arch foot steel plate, extension steel plate and sealed door are all provided with grooves, and the combined sealing strips are embedded in the grooves. The installation of the combined sealing strips can greatly improve the sealing performance between the embedded steel plate and the arch foot port, between two adjacent extension steel plates, and between two adjacent sealing doors, and reduce the influence of the gap at the connection on the test detection.

[0020] Furthermore, the combined sealing strip has a double-layer structure, the outer layer of the combined sealing strip is water-swellable rubber, and the inner layer of the combined sealing strip is a rubber elastic sealing pad, so that the combined sealing strip has certain compressibility and sealing performance. The outer layer material can undergo chemical and physical reactions with the medium in the air to rapidly expand and densely fill the space in contact with the air. When the material is under pressure, a reverse reaction will occur and return to the original material to ensure the vacuum degree inside the pipe network structure.

[0021] Furthermore, guide rail side walls are provided on the concrete base plate and the rear welded base plate. The temperature control system includes an integrator and a temperature controller. The integrator is installed on the guide rail side wall. The integrator includes a heater and a temperature sensor. The heater and the temperature sensor are electrically connected to the temperature controller. The heater and the temperature sensor are continuously and multi-sectionedly distributed inside the guide rail side wall. Three heaters are grouped together, and a temperature sensor is configured to monitor the centralized temperature.

[0022] Furthermore, the inner walls of the flexible pipe joint and the rigid pipe body are provided with data collectors, which include distributed optical fiber sensors, temperature sensors and pressure sensors. The distributed optical fiber sensors, temperature sensors and pressure sensors are all electrically connected to the data receiving terminal to facilitate the collection of temperature, pressure and other data.

[0023] The test method of the experimental device simulating the low vacuum transport pipe network structure as described above is characterized by comprising the following steps:

[0024] S1. Assemble the experimental device, complete the electrical connection between the data acquisition device and the data receiving terminal through the data wiring valve, and close each valve to ensure that the interior of the assembled low vacuum flexible pipeline is a completely closed space at this time, turn on the 3D3CPIV system, infrared thermal imager and data acquisition device, let it stand for a period of time, and observe the sealing effect of the assembled low vacuum flexible pipeline at this time;

[0025] S2. First, heat the induction particles in the particle release instrument to the temperature observed by the infrared thermal imager, then open the particle release instrument to release the induction particles, so that the induction particles are freely dispersed along the assembled low vacuum flexible pipeline, and let it stand for a period of time. The position and change state of the induction particles in the assembled low vacuum flexible pipeline are monitored by the 3D3C PIV system and the infrared thermal imager. If there is a poor sealing effect, the position of the poor sealing effect is obtained by observing the change of the induction particles, and timely processing is carried out;

[0026] S3. If the assembled low vacuum flexible pipeline is in a sealed state at this time, the air medium and the sensing particles in the assembled low vacuum flexible pipeline are sucked by the vacuum control system, and the direction of the air medium and the sensing particles in the assembled low vacuum flexible pipeline is observed by the 3D3C PIV system and the infrared thermal imager;

[0027] S4. Control the exchange of gas inside and outside the assembled low vacuum flexible pipeline through the vacuum control system and adjust it to the air pressure value required for the test;

[0028] S5. Control the temperature of the guide rail side wall inside the assembled low vacuum flexible pipeline through the temperature control system and adjust it to the temperature environment required for the test;

[0029] S6. By changing the number of corrugations of the wavy flexible pipe segment structure, different wavy flexible pipe segment structures are obtained, and through the above test process, the optimal structure type is obtained.

[0030] This test method has simple steps. It can not only create a real water and soil environment under the special working conditions of large-scale low-vacuum pipeline networks in low-vacuum environments through vacuum control systems, temperature control systems, and load control systems, but also simulate the working conditions during disaster response, especially the low vacuum, high temperature, water and soil pressure environment, and disaster environment of low-vacuum tunnel structures. The experimental results can verify the air tightness and structural mechanical properties of the pipeline structure under low-vacuum transportation environments, and provide basic data support and technical support for the subsequent application of low-vacuum pipelines in low-vacuum magnetic levitation transportation. It can also find a wavy flexible pipe segment structure suitable for the low-vacuum pipeline structure, which can ensure the water tightness and air tightness of the low-vacuum tunnel, ensure the vacuum state during the low-vacuum tunnel experiment, and at the same time ensure the toughness and full life cycle of the low-vacuum pipeline structure.

[0031] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0032] 1. The wavy flexible pipe segment structure is designed as a wavy structure with certain stretching and bending capabilities. It is connected with the two-part sealing structure system. Combined sealing strips are set at each sealing point to effectively ensure the airtightness of the low vacuum tunnel structure while improving the tunnel structure's ability to adapt to different deformations caused by temperature, pressure, etc.

[0033] 2. The combined sealing strip has a double-layer structure. The outer layer of the combined sealing strip is water-swellable rubber, and the inner layer of the combined sealing strip is a rubber elastic sealing pad, which makes the combined sealing strip have certain compressibility and sealing performance. The outer layer material can undergo chemical and physical reactions with the medium in the air to expand rapidly, filling the space in contact with the air densely. When the material is under pressure, a reverse reaction will occur and return to the original material to ensure the vacuum degree inside the pipe network structure.

[0034] 3. In the special working conditions of large-scale low-vacuum pipeline networks in low-vacuum environments, a real water and soil environment is created through vacuum control systems, temperature control systems, and load control systems. In particular, the working conditions during disaster response are simulated, and the low vacuum, high temperature, water and soil pressure environment, and disaster environment of the low-vacuum tunnel structure can be fully simulated. The experimental results can verify the air tightness and structural mechanical properties of the pipeline structure under the low-vacuum transportation environment, and provide basic data support and technical support for the subsequent application of low-vacuum pipelines in low-vacuum magnetic levitation transportation.

[0035] 4. A wavy flexible pipe segment structure suitable for the low-vacuum pipe network structure can be found to ensure the water tightness and air tightness of the low-vacuum tunnel, ensure the vacuum state during the low-vacuum tunnel experiment, and at the same time ensure the toughness and full life cycle of the low-vacuum pipe network structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below in conjunction with the accompanying drawings:

[0037] Figure 1 It is a structural schematic diagram of an experimental device in an experimental device and an experimental method for simulating a low vacuum transport pipe network structure of the present invention;

[0038] Figure 2 It is a structural schematic diagram of the wavy flexible pipe segment structure in the present invention;

[0039] Figure 3 is a cross-sectional view of the flexible pipe joint in the present invention;

[0040] Figure 4 It is a schematic diagram of the connection between the load control system and the flexible pipe joint in the present invention;

[0041] Figure 5 It is a structural schematic diagram of the sealing pipe joint structure in the present invention;

[0042] Figure 6 It is a cross-sectional schematic diagram of the connection between the arch foot steel plate, the combined sealing strip and the rear welded bottom plate in the present invention;

[0043] Figure 7 It is a cross-sectional schematic diagram of the connection between the rear-welded bottom plate, the combined sealing strip and the concrete bottom plate in the present invention;

[0044] Figure 8 It is a structural schematic diagram of the sealing door in the present invention;

[0045] Fig. 9 It is a schematic diagram of the installation of the heater and the temperature sensor in the present invention;

[0046] Fig.10 A graph showing the change of the internal air pressure of the pipeline with time when the gas is extracted in the present invention;

[0047] Fig.11 is a flow chart of the test method in the present invention;

[0048] In the figure: 1-sealed pipe section structure; 2-wavy flexible pipe section structure; 3-infrared thermal imager; 4-3D3CPIV system; 5-flange splicing bolts; 6-temperature controller; 7-particle release instrument; 8-vacuum control system; 9-data receiving terminal; 10-flexible pipe section; 11-guide rail side wall; 12-rear welded bottom plate; 13-arch foot steel plate; 14-embedded steel plate; 15-combined sealing strip; 16-water-swelling rubber; 17-rubber elastic sealing pad; 18-concrete bottom plate; 19-integrator; 20-data collector; 21-wavy pipe pattern; 22-load control system; 23-sealed door; 24-exhaust valve; 25-particle release valve; 26-data wiring valve; 27-rigid pipe body; 28-extension steel plate; 29-heater; 30-temperature sensor. DETAILED DESCRIPTION

[0049] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0050] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0052] like Figures 1 to 9 As shown, an experimental device for simulating a low vacuum transport pipe network structure of the present invention includes an assembled low vacuum flexible pipe, a temperature control system, a particle release instrument 7, a vacuum control system 8, an infrared thermal imager 3, a 3D3C PIV system 4 and a data receiving terminal 9. The temperature control system, the particle release instrument 7, the vacuum control system 8, the infrared thermal imager 3 and the 3D3C PIV system 4 are all electrically connected to the data receiving terminal 9. The data receiving terminal 9 can be a computer.

[0053] The assembled low-vacuum flexible pipeline includes a sealed pipe segment structure 1 and a wavy flexible pipe segment structure 2 which are arranged at intervals; the wavy flexible pipe segment structure 2 includes a flexible pipe segment 10 and a rear-welded bottom plate 12, the flexible pipe segment 10 is a wavy structure, the outer side of the flexible pipe segment 10 is provided with a wavy pipe pattern 21, the arch foot position of the flexible pipe segment 10 is provided with an arch foot steel plate 13 extending horizontally outward, the outer side of the rear-welded bottom plate 12 is provided with an embedded steel plate 14, the arch foot steel plate 13 and the embedded steel plate 14 are aligned with each other and fixedly connected by flange splicing bolts 5, the rear-welded bottom plate 12 is provided with flange splicing bolts 5, and the bottom of the wavy flexible pipe segment structure 2 is provided with a load control system 22, by changing the size of the wavelength, the flexible pipe segment 10 has greater tensile and bending properties, and the form of the flexible pipe segment 10 is adjusted to adapt to changes in load, and the load here refers to displacement.

[0054] The sealed pipe segment structure 1 includes a concrete base plate 18 and a rigid pipe body 27. The rigid pipe body 27 is a semicircular ring structure. The arch foot position of the rigid pipe body 27 is provided with an arch foot steel plate 13 extending horizontally outward. Embedded steel plates 14 are symmetrically provided on both sides of the concrete base plate 18. The arch foot steel plate 13 and the embedded steel plate 14 are aligned with each other and fixedly connected by flange splicing bolts 5. The concrete base plate 18 is provided with flange splicing bolts 5. Through the structural design of the rigid pipe body 27, it can be fully fitted to the inner wall of the tunnel structure, thereby improving the stability and reliability of the sealed pipe segment structure 1.

[0055] Sealing doors 23 are provided at both ends of the assembled low-vacuum flexible pipeline, and the sealing doors 23 are connected by flange splicing bolts 5. The sealing doors 23 are provided with an exhaust valve 24, a particle release valve 25 and a data wiring valve 26. The exhaust valve 24 is electrically connected to the vacuum control system 8, the particle release valve 25 is electrically connected to the particle release instrument 7, and the data wiring valve 26 is electrically connected to the data receiving terminal 9.

[0056] Extension steel plates 28 are provided at the positions where the rigid pipe body 27 and the flexible pipe section 10 contact each other. Two adjacent extension steel plates 28 are fixedly connected by flange splicing bolts 5 to improve the connection stability and reliability between the rigid pipe body 27 and the flexible pipe section 10.

[0057] The embedded steel plate 14, the arch foot steel plate 13, the extension steel plate 28 and the sealing door 23 are all provided with grooves, and the combined sealing strip 15 is embedded in the groove. The installation of the combined sealing strip 15 can greatly improve the sealing performance between the embedded steel plate 14 and the arch foot port, between two adjacent extension steel plates 28, and between two adjacent sealing doors 23, and reduce the influence of the gap at the connection on the test detection.

[0058] The combined sealing strip 15 is a double-layer structure. The outer layer of the combined sealing strip 15 is a water-swellable rubber 16, and the inner layer of the combined sealing strip 15 is a rubber elastic sealing pad 17, so that the combined sealing strip 15 has certain compressibility and sealing performance. The outer layer material can undergo chemical and physical reactions with the medium in the air to quickly expand and fill the space in contact with the air. When the material is under pressure, a reverse reaction will occur and return to the original material to ensure the vacuum degree inside the pipe network structure.

[0059] Guide rail side walls 11 are provided on the concrete base plate 18 and the rear welded base plate 12. The temperature control system includes an integrator 19 and a temperature controller 6. The integrator 19 is installed on the guide rail side wall 11. The integrator 19 includes a heater 29 and a temperature sensor 30. The heater 29 and the temperature sensor 30 are both electrically connected to the temperature controller 6. The heaters 29 and the temperature sensors 30 are continuously and multi-sectionedly distributed inside the guide rail side wall 11. Three heaters 29 are grouped together, and a temperature sensor 30 is configured to monitor the centralized temperature.

[0060] The inner walls of the flexible pipe joint 10 and the rigid pipe body 27 are both provided with a data collector 20, which includes a distributed optical fiber sensor, a temperature sensor and a pressure sensor. The distributed optical fiber sensor, the temperature sensor and the pressure sensor are all electrically connected to the data receiving terminal 9, so as to facilitate the collection of temperature, pressure and other data. The distributed optical fiber sensor in the present invention preferably adopts a surface-mounted optical fiber grating strain sensor - FBG strain gauge, the temperature sensor and the temperature sensor 30 preferably adopt a patch-type PT100 temperature sensor platinum thermal resistor, and the pressure sensor preferably adopts a meacon American control diffused silicon pressure transmitter sensor.

[0061] The temperature control system is used to detect and control the temperature of the sealed pipe segment structure 1 and the wavy flexible pipe segment structure 2; the particle release instrument 7 is used to release the induction particles to the sealed pipe segment structure 1 and the wavy flexible pipe segment structure 2; the vacuum control system 8 is used to adjust the vacuum degree inside the assembled low vacuum flexible pipeline; the infrared thermal imager 3 and the 3D3C PIV system 4, the infrared thermal imager 3 and the 3D3C PIV system 4 are distributed on both sides of the assembled low vacuum flexible pipeline, and are used to monitor the position and change state of the induction particles inside the assembled low vacuum flexible pipeline; the data receiving terminal 9 is used to receive and analyze the data of the temperature control system, the particle release instrument 7, the infrared thermal imager 3 and the 3D3C PIV system 4, judge the data changes of the stress, temperature and air pressure inside the assembled low vacuum flexible pipeline, and determine the sealing effect of the assembled low vacuum flexible pipeline.

[0062] The experimental device formed by the above structure has a certain stretching and bending ability, which can effectively ensure the airtightness of the low-vacuum tunnel structure, and at the same time improve the ability of the tunnel structure to adapt to different deformations caused by temperature, pressure, etc. At the same time, under the special working conditions of the large-scale low-vacuum pipeline network structure in the actual low-vacuum environment, it can realize a comprehensive simulation of the actual environment of the low-vacuum tunnel pipeline network structure, and can verify the airtightness and structural mechanical properties of the pipeline network structure in the low-vacuum transportation environment.

[0063] like Fig.11 As shown, a test method for an experimental device simulating a low vacuum transport pipe network structure comprises the following steps:

[0064] S1, assemble the experimental device, complete the electrical connection between the data collector 20 and the data receiving terminal 9 through the data wiring valve 26, and close each valve to ensure that the interior of the assembled low vacuum flexible pipeline is a completely closed space at this time, turn on the 3D3C PIV system 4, the infrared thermal imager 3 and the data collector 20, let it stand for a period of time, and observe the sealing effect of the assembled low vacuum flexible pipeline at this time;

[0065] S2, first heat the induction particles in the particle release instrument 7 to the temperature observed by the infrared thermal imager 3, then open the particle release instrument 7 to release the induction particles, so that the induction particles are freely dispersed along the assembled low vacuum flexible pipeline, and stand for a period of time, and monitor the position and change state of the induction particles in the assembled low vacuum flexible pipeline through the 3D3C PIV system 4 and the infrared thermal imager 3. If there is a poor sealing effect, the position of the poor sealing effect is obtained by observing the change of the induction particles, and timely processing is carried out;

[0066] S3, if the assembled low vacuum flexible pipeline is in a sealed state at this time, the vacuum control system 8 starts to absorb the air medium and the sensing particles in the assembled low vacuum flexible pipeline, and the 3D3C PIV system 4 and the infrared thermal imager 3 are used to observe the direction of the air medium and the sensing particles in the assembled low vacuum flexible pipeline;

[0067] The vacuum control system 8 is turned on to extract the air medium and the sensing particles inside the pipeline structure. At the same time, the pressure display on the data collector 20 inside the pipeline is observed through the data receiving terminal 9. When the pressure reaches a certain value, the experimenter can operate the vacuum control system 8 to stop extracting the air medium and the sensing particles inside the pipeline structure. At this time, there is no gas exchange between the pipeline structure and the external gas, and the pressure value stops at a fixed value. At the same time, the external gas of the pipeline can be introduced into the pipeline through the vacuum control system 8 to change the internal pressure of the pipeline structure. The experimenter can achieve different vacuum pressure values ​​through the above operations, such as Fig.10 Figure 2 shows the change in pressure inside the pipeline over time when gas is extracted.

[0068] Negative pressure inside the pipeline will cause stress, strain and deformation of the structure. The test personnel can observe the changes in stress, temperature and air pressure data inside the pipeline through distributed optical fiber sensors, temperature sensors and pressure sensors (gas-water pressure). The 3D3C PIV system 4 and infrared thermal imager 3 can observe the distribution of air medium and sensing particles inside the tunnel, and determine the sealing effect of the pipeline structure by whether there is exchange of internal and external airflow.

[0069] S4, controlling the exchange of gas inside and outside the assembled low vacuum flexible pipeline through the vacuum control system 8, and adjusting the gas pressure to the required value for the test;

[0070] The temperature control system can simulate the temperature changes caused by the superconducting coils of the tunnel structure. The test personnel can adjust the temperature changes of each section inside the pipeline through the temperature control system. The heaters 29 are grouped into three and are equipped with a temperature sensor 30. The heating temperature of the heaters 29 is adjusted through the temperature controller 6. The test personnel obtain the real-time temperature of the heaters 29 at this time by observing the temperature display on the data receiving terminal 9. The heaters 29 of each group can be controlled separately. The test personnel control the temperature of each group of heaters 29 through the temperature controller 6 and monitor the temperature display on the data receiving terminal 9 in real time, so as to achieve the local temperature increase of the guide rail side wall 11 inside the pipeline structure or the temperature increase of a certain section.

[0071] The temperature stress and strain generated by the temperature difference between the inside and outside of the pipeline are transmitted to the data receiving terminal 9 through the distributed optical fiber sensor and the pressure sensor (gas-water pressure). The temperature sensor can detect the temperature change of the pipe network structure. The 3D3C PIV system 4 and the infrared thermal imager 3 observe the distribution changes of the air medium and the sensing particles inside the tunnel caused by the temperature change of the guide rail side wall 11 and the temperature change inside the tunnel structure. If the pipe network structure is unstable due to the temperature change, the sealing effect of the pipe network structure can be determined by whether there is an exchange of internal and external airflow.

[0072] S5. Control the temperature of the guide rail side wall 11 inside the assembled low-vacuum flexible pipeline through a temperature control system and adjust it to the temperature environment required for the test;

[0073] The test personnel can simulate the changes in load and displacement caused by the occurrence of disasters through the load control system 22 at the bottom of the wavy flexible pipe segment structure 2. The two ends of the pipeline structure are fixed, and the load control system 22 itself has pressure display and displacement display. The load control system 22 is directly applied to the flexible pipe segment 10. Under the interaction between the two, the force parameters continue to increase. When the force is too large, the load control system 22 can be used to unload and reduce the interaction force between them; the displacement display can also be observed and the displacement value can be set. When the pipeline structure reaches the set displacement value under the action of the load control system 22, the load control system 22 automatically stops working. When the displacement is too large, the load control system 22 can also be used to unload. The test personnel can control the deformation of the pipeline structure through the process of loading and unloading.

[0074] The stress and strain of the pipe network structure caused by pipeline deformation are transmitted to the data receiving terminal 9 through distributed optical fiber sensors and pressure sensors (gas and water pressure). The temperature sensor can detect the temperature change of the pipe network structure. When the load reaches a certain value, the pipe network structure will become unstable. The 3D3C PIV system 4 and the infrared thermal imager 3 observe the distribution changes of the air medium and the sensing particles inside the tunnel caused by the load change. Whether there is an exchange of internal and external airflows is used to determine the damage position of the pipe network structure, and the limit values ​​of each sensor parameter at this time are recorded as the limit damage that this type of corrugated flexible pipe segment structure 2 can bear.

[0075] S6. By changing the number of corrugations of the wavy flexible pipe segment structure 2, different wavy flexible pipe segment structures 2 are obtained, and through the above test process, the optimal structure type is obtained.

[0076] The number of ripples satisfies the equation:

[0077] Among them, n: number of corrugations; L: length of flexible pipe section 10; x: wavelength of corrugations. Through the above test plan process, a certain evaluation process is formulated to obtain the optimal structure type, which provides a certain theoretical basis for actual engineering design.

[0078] The test method has simple steps. It can not only create a real water and soil environment under the special working conditions of a large low-vacuum pipeline network in a low-vacuum environment through the vacuum control system 8, the temperature control system, and the load control system 22, especially simulate the working conditions when responding to disasters, but also comprehensively simulate the low vacuum, high temperature, water and soil pressure environment, and disaster environment of the low-vacuum tunnel structure. The experimental results can verify the air tightness and structural mechanical properties of the pipeline structure under the low-vacuum transportation environment, and provide basic data support and technical support for the subsequent application of low-vacuum pipelines in low-vacuum magnetic levitation transportation. It can also find a wavy flexible pipe segment structure 2 suitable for the low-vacuum pipeline network structure, which can ensure the water tightness and air tightness of the low-vacuum tunnel, ensure the vacuum state of the low-vacuum tunnel during the experiment, and at the same time ensure the toughness and full life cycle of the low-vacuum pipeline network structure.

[0079] The above are only specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent replacements or modifications made based on the present invention to achieve basically the same technical effects are all included in the protection scope of the present invention.

Claims

1. A test method for an experimental device simulating a low vacuum transport pipe network structure, characterized in that: The experimental device includes An assembled low vacuum flexible pipeline, comprising a sealed pipe segment structure and a corrugated flexible pipe segment structure arranged at intervals; a temperature control system for detecting and controlling the temperature of the sealed pipe joint structure and the corrugated flexible pipe joint structure; a particle release instrument, used for releasing induction particles to the sealed pipe section structure and the wavy flexible pipe section structure; A vacuum control system for adjusting the vacuum degree inside the assembled low-vacuum flexible pipeline; An infrared thermal imager and a 3D3C PIV system, the infrared thermal imager and the 3D3C PIV system are distributed on both sides of the assembled low vacuum flexible pipeline, and are used to monitor the position and change state of the sensing particles inside the assembled low vacuum flexible pipeline; and a data receiving terminal, used to receive and analyze data from the temperature control system, the particle release instrument, the infrared thermal imager and the 3D3C PIV system, judge the data changes of the internal stress, temperature and air pressure of the assembled low vacuum flexible pipeline, and determine the sealing effect of the assembled low vacuum flexible pipeline; The following steps are involved: S1. Assemble the experimental device, complete the electrical connection between the data collector and the data receiving terminal through the data wiring valve, and close each valve to ensure that the interior of the assembled low vacuum flexible pipeline is a completely closed space. Turn on the 3D3C PIV system, infrared thermal imager and data collector, let it stand for a period of time, and observe the sealing effect of the assembled low vacuum flexible pipeline; S2. First, heat the induction particles in the particle release instrument to the temperature observed by the infrared thermal imager, then open the particle release instrument to release the induction particles, so that the induction particles are freely dispersed along the assembled low vacuum flexible pipeline, and let it stand for a period of time. The position and change state of the induction particles in the assembled low vacuum flexible pipeline are monitored by the 3D3C PIV system and the infrared thermal imager. If there is a poor sealing effect, the position of the poor sealing effect is obtained by observing the change of the induction particles, and timely processing is carried out; S3. If the assembled low vacuum flexible pipeline is in a sealed state at this time, the air medium and the sensing particles in the assembled low vacuum flexible pipeline are sucked by the vacuum control system, and the direction of the air medium and the sensing particles in the assembled low vacuum flexible pipeline is observed by the 3D3C PIV system and the infrared thermal imager; S4. Control the exchange of gas inside and outside the assembled low vacuum flexible pipeline through the vacuum control system and adjust it to the air pressure value required for the test; S5. Control the temperature of the guide rail side wall inside the assembled low vacuum flexible pipeline through the temperature control system and adjust it to the temperature environment required for the test; S6. By changing the number of corrugations of the wavy flexible pipe segment structure, different wavy flexible pipe segment structures are obtained, and through the above test process, the optimal structure type is obtained.

2. The test method of the experimental device for simulating a low vacuum transport pipe network structure according to claim 1, characterized in that: The sealed pipe joint structure includes a concrete base plate and a rigid pipe body. The rigid pipe body is a semicircular ring structure. The arch foot position of the rigid pipe body is provided with an arch foot steel plate extending horizontally outward. Embedded steel plates are symmetrically provided on both sides of the concrete base plate. The arch foot steel plate is aligned with the embedded steel plate and fixedly connected by flange splicing bolts. The concrete base plate is provided with the flange splicing bolts.

3. The test method of the experimental device for simulating a low vacuum transport pipe network structure according to claim 2, characterized in that: The wavy flexible pipe segment structure includes a flexible pipe segment and a rear-welded bottom plate. The flexible pipe segment is a wavy structure. The outer side of the flexible pipe segment is provided with a wavy pipe pattern. The arch foot position of the flexible pipe segment is provided with an arch foot steel plate extending horizontally outward. The outer side of the rear-welded bottom plate is provided with the embedded steel plate. The arch foot steel plate and the embedded steel plate are aligned with each other and are fixedly connected by the flange splicing bolts. The rear-welded bottom plate is provided with the flange splicing bolts. A load control system is provided at the bottom of the wavy flexible pipe segment structure.

4. The test method of the experimental device for simulating a low vacuum transport pipe network structure according to claim 3, characterized in that: Sealing doors are provided at both ends of the assembled low-vacuum flexible pipeline, and the sealing doors are connected by the flange splicing bolts. The sealing doors are provided with an exhaust valve, a particle release valve and a data wiring valve. The exhaust valve is electrically connected to the vacuum control system, the particle release valve is electrically connected to the particle release instrument, and the data wiring valve is electrically connected to the data receiving terminal.

5. The test method of the experimental device for simulating a low vacuum transport pipe network structure according to claim 4, characterized in that: Extension steel plates are provided at the positions where the rigid pipe body and the flexible pipe joint contact each other, and two adjacent extension steel plates are fixedly connected by the flange splicing bolts.

6. The test method of the experimental device for simulating a low vacuum transport pipe network structure according to claim 5, characterized in that: The embedded steel plate, the arch foot steel plate, the extension steel plate and the sealing door are all provided with grooves, and the combined sealing strips are embedded in the grooves.

7. The test method of the experimental device for simulating a low vacuum transport pipe network structure according to claim 6, characterized in that: The combined sealing strip is a double-layer structure, the outer layer of the combined sealing strip is water-swellable rubber, and the inner layer of the combined sealing strip is a rubber elastic sealing pad.

8. The test method of the experimental device for simulating a low vacuum transport pipe network structure according to claim 3, characterized in that: The concrete base plate and the rear weld base plate are both provided with guide rail side walls. The temperature control system includes an integrator and a temperature controller. The integrator is installed on the guide rail side walls. The integrator includes a heater and a temperature sensor. The heater and the temperature sensor are both electrically connected to the temperature controller.

9. The test method of the experimental device for simulating a low vacuum transport pipe network structure according to claim 3, characterized in that: The inner walls of the flexible pipe joint and the rigid pipe body are both provided with data collectors, which include distributed optical fiber sensors, temperature sensors and pressure sensors. The distributed optical fiber sensors, temperature sensors and pressure sensors are all electrically connected to the data receiving terminal.

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