Construction method for secondary lining concrete heat insulation layer of hole opening section in alpine region

Abstract

The invention discloses a construction method for a secondary lining concrete heat insulation layer of a portal section in an alpine region, and relates to the technical field of civil engineering in cold regions, the construction method comprises the following steps: S1, deashing and decontaminating the surface of a secondary lining; s2, a U-shaped component is installed; s3, the electric heating plate is fixed through a wing plate of the U-shaped component, and then a heat preservation plate is installed; S4, an air channel is formed in the heat preservation layer, a monitoring assembly is installed in the air channel, and then a temperature collecting assembly and a control assembly are installed in the hole; the monitoring assembly is used for collecting the flowing direction of gas in the gas channel, and the control assembly judges the position where the temperature difference occurs in the heat preservation layer according to the gas flowing scheme, controls the temperature collection assembly to conduct temperature collection on the position where the temperature difference occurs, obtains a set of temperature information and selects the maximum value in the set of temperature information as a standard value. And then the electric heating plate is controlled to work according to the temperature information until the temperature information of the position where the temperature difference occurs reaches the standard value, and automatic heating of the secondary lining is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of cold region civil engineering, and particularly to a construction method for the heat insulation and preservation layer of the secondary lining concrete at the portal section in alpine regions. Background Technique

[0002] The portal section of tunnels in alpine regions (such as the Qinghai-Tibet Plateau, the Arctic Circle, Siberia, etc.) faces severe challenges such as extreme low temperatures (annual average temperature of -10°C to -30°C), intense freeze-thaw cycles (annual cycle times reaching 50 to 100 times), and frost heaving forces (up to 2 to 5 MPa). As the core load-bearing layer of the tunnel structure, the secondary lining at the portal section needs to achieve the following objectives through the heat insulation and preservation layer: preventing concrete frost damage: avoiding the freezing and expansion of internal moisture in concrete caused by low temperatures, which may lead to cracking (the frost heaving stress can cause the crack width to be > 0.3 mm); inhibiting freeze-thaw cycle damage: reducing the fatigue deterioration of materials caused by temperature fluctuations (after 100 freeze-thaw cycles, the concrete strength loss can reach 30% to 50%); maintaining the thermal stability of the structure: controlling the temperature difference between the inside and outside of the lining (usually ≤ 15°C) to prevent thermal stress cracks (for every 10°C increase in temperature difference, the thermal stress increases by about 2 MPa).

[0003] In the prior art, mainly two types of passive heat preservation and active heat preservation technologies are adopted. Among them, the active heat preservation technology includes an electric tracing system: embedding carbon fiber heating cables (power 15 to 25 W / m) in the lining, and maintaining the surface temperature of the lining > 0°C through a temperature controller (for example, the energy consumption of a certain tunnel on the Sichuan-Tibet Line is about 8 kWh / m²·year). And geothermal utilization: embedding geothermal pipes to circulate antifreeze (ethylene glycol solution) and using the geothermal temperature (5 to 10°C) to transfer heat (the case of the Hvalfjörður Tunnel in Iceland).

[0004] However, due to the characteristics of high radiation and multiple sunshine in alpine regions, there is a temperature difference between the area receiving sunshine at the portal and the area not receiving sunshine. Continuous active heat preservation is likely to cause energy waste, and the scheme of heating after unified temperature measurement is likely to ignore the positions with lower temperatures, thus triggering freeze-thaw cycles at these positions and affecting the stability of the structure. Summary of the Invention

[0005] The purpose of the present invention is to provide a construction method for the heat insulation and preservation layer of the secondary lining concrete at the portal section in alpine regions to solve the above problems.

[0006] The present invention is achieved through the following technical solutions: A construction method for the heat insulation and preservation layer of the secondary lining concrete at the portal section in alpine regions includes: S1: Select insulation boards, keels, fiber-reinforced device boards, and several electric heating plates. Subsequently, clean the ash and dirt on the surface of the secondary lining, and repair the defective parts on the surface of the secondary lining; S2: Select several U-shaped members, measure, set out the lines and install the U-shaped members on the surface of the secondary lining; S3: Fix the electric heating plate through the wing plates of the U-shaped members, then install the heat preservation plate, and press the heat preservation plate to make the wing plates of the U-shaped members enter the heat preservation plate: S4: Open an air duct in the heat preservation layer, install a monitoring component in the air duct, then install a temperature acquisition component and a control component inside the opening, and electrically connect the monitoring component, the temperature acquisition component and the electric heating plate to the control component; The monitoring component is used to collect the gas flow direction inside the air duct. The control component judges the position where the temperature difference appears in the heat preservation layer according to the gas flow scheme, and controls the temperature acquisition component to collect the temperature of the position where the temperature difference appears, obtains a set of temperature information, selects the maximum value in this set of temperature information as the standard value, and then controls the electric heating plate to work according to the temperature information until the temperature information of the position where the temperature difference appears reaches the standard value; S5: Fix the keel through the U-shaped members, install the fiber reinforced device plate on the side of the keel away from the heat preservation plate with self-tapping screws, and then carry out joint filling to complete the construction of the secondary lining concrete heat insulation layer at the opening section in alpine regions.

[0007] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. In the present invention, due to the design of the heat preservation plate and the U-shaped members, compared with the prior art, there is no need to cut and divide the heat preservation plate during the construction process of this solution, so that the splicing joints of the heat preservation plate can be greatly reduced, the installation is convenient and fast, and while reducing the working steps of the operators, the heat preservation effect of the structure can also be improved; 2. In the present invention, due to the design of the electric heating plate, the electric heating plate is used to heat the secondary lining to ensure that the surface temperature of the secondary lining is at a suitable temperature, realizing active heat preservation, improving the stability of the structure after construction, and avoiding the influence of freeze-thaw cycles on the structure; 3. In the present invention, due to the design of the monitoring component, the temperature acquisition component and the control component, through the coordinated work with the electric heating plate, according to the gas flow direction in the air duct inside the heat preservation layer, roughly judge the position where the temperature difference changes, and then the control component controls the temperature acquisition component to only collect the temperature of the position where the temperature difference changes, and controls the electric heating plate at the corresponding position to work according to the acquisition result; Compared with the prior art, in this solution, the monitoring component preliminarily screens the positions where temperature changes occur on the surface of the secondary lining, and the temperature acquisition component only works at the positions where temperature changes occur, which helps to quickly expand the scope of data acquisition while reducing the working energy consumption of each structure of the post-construction insulation layer and improving the service life of the insulation layer. At the same time, compared with the solution of synchronously heating the surface of the secondary lining, this solution monitors the temperature at each position of the secondary lining to achieve automated differential heating of the secondary lining, which helps to avoid continuously heating the positions with higher temperatures or ignoring the positions with lower temperatures, thereby reducing the occurrence of freeze-thaw cycles at each position of the secondary lining and improving the service life of the secondary lining and the insulation layer.

[0008] Further, in S1, a photovoltaic solar power generation component is selected, and according to the geographical conditions of the tunnel entrance, the position with the longest sunshine duration is selected to install the photovoltaic solar power generation component, and the photovoltaic solar power generation component is used to supply power to the electric heating plate, the monitoring component, the temperature acquisition component, and the control component.

[0009] Beneficial effects: Compared with the prior art, the photovoltaic solar power generation component is used in this solution, making full use of the characteristics of strong radiation and abundant sunshine in alpine regions to generate electricity using clean energy and saving power loss.

[0010] Further, in S4, the monitoring component includes a conductive rod and a plurality of storage batteries. The conductive rod is made of metal, and an insulating cover is sleeved on any end of the conductive rod. The insulating cover is fixedly connected to the side wall of the air duct, and a plurality of conductive strips are fixedly connected to the insulating cover. The number of storage batteries electrically connected to each conductive strip is different. The conductive rod is electrically connected to a current sensor, and the current sensor is used to collect the current information passing through the conductive rod. The conductive strip is used to connect the circuit between the current sensor and the storage battery. The control component judges the position of the conductive strip electrically connected to the conductive rod according to the current information and obtains the gas flow direction in the air duct according to the position of the conductive strip.

[0011] Beneficial effects: Compared with the prior art, the solution of combining the conductive rod and the conductive strip with the current sensor has the sensor arranged outside, which helps with post-construction inspection and maintenance, reduces the later maintenance cost and steps, and the sensor in this solution is less affected by temperature, which helps to improve the accuracy of the data collected by the monitoring component.

[0012] Further, the temperature acquisition component includes an infrared temperature sensor and a multi-axis motion platform. The infrared sensor is fixedly connected to the multi-axis motion platform, and the multi-axis fixed platform is installed inside the opening.

[0013] Beneficial effects: Compared with the prior art, the collaborative work of the infrared temperature sensor and the multi-axis motion platform realizes the collection of the temperature at each position of the secondary lining through a single sensor, reducing the input cost of the sensor in the implementation process of the solution. At the same time, since the sensor in this solution is arranged outside the structure, the cost and steps of subsequent maintenance are further reduced.

[0014] Further, in S2, the U-shaped members are arranged in a matrix.

[0015] Beneficial effects: Compared with the prior art, in this solution, the U-shaped members arranged in a matrix avoid the uneven distribution of the tensile force exerted on structures such as the thermal insulation layer in the future, thus preventing the phenomenon of stress concentration. At the same time, the U-shaped members arranged in a matrix also make the sizes of the electric heating plates arranged therein uniform, which is helpful for the preparation, transportation, and storage of the electric heating plates.

[0016] Further, the steps of installing the thermal insulation board in S3 include: S3-1: Cutting the thermal insulation board according to the size of the second lining; S3-2: Pressing the thermal insulation board to embed the wing plates of the U-shaped member into the thermal insulation board, and continuing to push the thermal insulation board to make the side of the thermal insulation board close to the electric heating plate fit with the electric heating plate.

[0017] Beneficial effects: Compared with the prior art, in the installation steps of the thermal insulation board in this solution, by reducing the gap between the electric heating plate and the thermal insulation board, it is avoided that there is a large cavity between the two, thus preventing the formation of a local thermal bridge effect and affecting the overall thermal insulation effect. At the same time, it can also reduce the risk of condensation between the two and reduce the risk of their separation after construction.

[0018] Further, the steps of installing the keel in S5 include: S5-1: Orienting the opening direction of the keel towards the thermal insulation board and pressing the keel so that the U-shaped member passes through the keel and the keel is embedded into the thermal insulation board; S5-2: Bending the wing plates of the U-shaped member towards each other, so that the wing plates of the U-shaped member cross and fasten the keel to complete the installation of the keel.

[0019] Beneficial effects: Compared with the prior art, in this solution, the keel is fixed by the U-shaped member, without complex welding, with convenient operation, flexible adjustment, and significant mechanical advantages.

[0020] Further, after the joint is filled in S5, a vacuum pump is used to create a negative pressure in the heat-insulating and thermal-insulating layer, and the change in the air pressure in the heat-insulating and thermal-insulating layer is continuously monitored. Only when the difference in the air pressure change within the set time is less than the preset value, the air pressure in the heat-insulating and thermal-insulating layer is returned to the atmospheric pressure by the vacuum pump.

[0021] Beneficial effects: Compared with the prior art, after the construction of the thermal insulation layer is completed in this solution, by generating negative pressure inside it and monitoring the air pressure change inside the thermal insulation layer after the negative pressure is generated, the airtightness of the thermal insulation layer can be judged, which helps to improve the quality of the finally constructed thermal insulation layer. When the difference in air pressure change within the set time is less than the preset value, the airtightness of the thermal insulation layer meets the standard, and then the inside of the thermal insulation layer is restored to atmospheric pressure to avoid damage to the thermal insulation layer structure caused by negative pressure. If the difference in air pressure change within the set time is greater than or equal to the preset value, the airtightness of the thermal insulation layer constructed this time does not meet the standard. Subsequently, the operator can choose methods such as the marked gas monitoring method to find the air leakage point, and judge whether rework or repair is required according to the size and location of the air leakage point.

[0022] Further, the material of the insulation board in S1 is phenolic foam material, and the thickness is not less than fifty millimeters.

[0023] Beneficial effects: Compared with other solutions, this solution utilizes the characteristics of phenolic foam material to avoid the occurrence of thermal convection between the gas inside the air duct and the outside gas, which affects the accuracy of data collection by the monitoring component.

[0024] Further, the photovoltaic solar power generation component includes a photovoltaic cell, a solar panel, and an inverter. The temperature acquisition component is also used to acquire the temperature of the solar panel. The control component judges the current sunlight condition according to the temperature of the solar panel, and controls the heating plate to work according to the current sunlight condition.

[0025] Beneficial effects: Compared with the prior art, this solution acquires the temperature of the solar panel through the temperature acquisition component, thereby judging the real-time sunlight state, so as to avoid heating the secondary lining at a time point with strong sunlight, resulting in too high a structural temperature and affecting the stability of the structure. Description of the Drawings

[0026] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not constitute a limitation to the embodiments of the present invention. In the drawings: Figure 1 is the flow chart of the present invention; Figure 2 is the plan view of the laying of the heating plate in the present invention; Figure 3 is the elevation view of the thermal insulation layer in the present invention; Figure 4 is the elevation view of the U-shaped member in the present invention; Figure 5 is the sectional view of the thermal insulation layer in the present invention; Figure 6 is the schematic diagram of the conductive rod part in the monitoring component in Embodiment 2 of the present invention.

[0027] The reference numerals represent: 1. Secondary lining; 2. U-shaped member; 21. Expansion bolt; 3. Electric heating plate; 4. Thermal insulation board; 5. Keel; 6. Self-tapping screw; 7. Fiber-reinforced device plate; 8. Monitoring component; 81. Conductive rod; 82. Insulating cover; 83. Conductive strip. Detailed implementation mode

[0028] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments and drawings. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and do not limit the present invention. It should be noted that the present invention has been in the actual R & D and use stage.

[0029] Embodiment 1 As Figures 1 to 5 shown, this embodiment includes S1: Select the thermal insulation board 4, keel 5, fiber-reinforced device plate 7 and several electric heating plates 3. Subsequently, clean and decontaminate the surface of the secondary lining 1, and repair the defective parts on the surface of the secondary lining 1. S2: Select several U-shaped members 2, measure and lay out the lines on the surface of the secondary lining 1 to install the U-shaped members 2. During the installation process, use a hand drill to drill holes at the layout positions, and then use expansion bolts 21 to fix the U-shaped members. Moreover, during installation, the opening directions of the U-shaped members 2 need to face the longitudinal direction of the tunnel corresponding to the portal in the same orientation. At the same time, the U-shaped members 2 are arranged in a matrix. The U-shaped members 2 arranged in a matrix make the subsequent tensile force applied to structures such as the thermal insulation layer evenly distributed, and it is not easy to have the stress concentration phenomenon caused by uneven tensile force distribution. At the same time, the U-shaped members 2 arranged in a matrix make the sizes of the electric heating plates 3 arranged therein uniform, which is convenient for design, production and transportation. S3: Fix the electric heating plate 3 through the wing plates of the U-shaped member 2, and then install the thermal insulation board 4, and press the thermal insulation board 4 to make the wing plates of the U-shaped member 2 enter the thermal insulation board 4.

[0030] Among them, the steps of installing the thermal insulation board 4 include: S3-1: Cut the thermal insulation board 4 according to the size of the second lining. S3-2: Press the thermal insulation board 4 to make the wing plates of the U-shaped member 2 embed into the thermal insulation board 4, and continue to push the thermal insulation board 4 to make the side of the thermal insulation board 4 close to the electric heating plate 3 closely fit with the electric heating plate 3.

[0031] S4: An air channel is opened in the thermal insulation layer, and a monitoring component 8 is installed in the air channel. In this embodiment, the monitoring component 8 includes a bump. Any side wall of the bump is adhesively fixed to the side wall of the air channel, and strain gauges are adhesively fixed to the remaining side walls of the bump. Subsequently, a temperature acquisition component and a control component are installed inside the opening. The monitoring component 8, the temperature acquisition component, and the electric heating plate 3 are all electrically connected to the control component. The temperature acquisition component includes a number of contact temperature sensors, and the contact temperature sensors are evenly arranged along the opening. In this embodiment, the control component is a controller, and the strain gauges, the contact temperature sensors, and the electric heating plate 3 are all electrically connected to the controller.

[0032] The monitoring component 8 is used to collect the gas flow direction inside the air channel. The control component judges the position where the temperature difference appears in the thermal insulation layer according to the gas flow scheme, and controls the temperature acquisition component to collect the temperature of the position where the temperature difference appears, obtaining a set of temperature information. The maximum value in this set of temperature information is selected as the standard value. Subsequently, the electric heating plate 3 is controlled to work according to the temperature information until the temperature information of the position where the temperature difference appears reaches the standard value. After the construction of the heat insulation layer is completed, during use, the strain gauges continuously collect the deformation information of each side wall of the bump. Due to the different influences of light or equipment heat radiation on each position of the opening and its corresponding tunnel, temperature differences appear at each position of the opening (for example, during the day, at the position that is not illuminated and far from the equipment, this position may be continuously in a negative temperature state with less influence from sunlight, etc., while at the position that can be illuminated, as the daytime temperature gradually rises, it will rise. At this time, there will be an obvious temperature difference between the two positions). Due to the thermal expansion of the gas, when the temperature difference appears, the gas density on the side with a higher temperature in the air channel is less than that on the side with a lower temperature. At this time, there is a pressure difference between the two sides of the gas. Under the action of the pressure, the high-pressure gas (i.e., the gas with a lower temperature) flows in the direction of the low-pressure gas (i.e., the gas with a higher temperature), forming an air current. When the air current passes through the bump, the air current impacts the bump, causing a slight deformation on the surface of the bump, that is, the strain information collected by the strain gauge at this position changes. Then, the direction of the air current flow can be judged by the position of the bump where the strain information changes, and the orientation where the temperature difference appears can be roughly judged according to the direction of the air current flow. For example: When the strain information corresponding to the left side of the bump changes, it can be roughly judged that the direction of the gas flow is from the left side to the right side. At this time, the temperature on the left side is lower than that on the right side. The controller controls the contact temperature sensors on the left and right sides to work, collects the temperature information at different positions on the left and right sides, obtains a set of temperature information. The controller screens out the maximum value from this set of temperature information and uses this value as the standard value. The controller starts the electric heating plates 3 on the left and right sides to actively heat the remaining positions except the standard value, and continuously collects the temperature information at the same time until the temperatures of all the heated positions reach the standard value, completing one active heat insulation of the secondary lining 1.

[0033] S5: Fix the keel 5 through the U-shaped member 2, and use self-tapping screws 6 to install the fiber-reinforced device plate 7 on the side of the keel 5 away from the thermal insulation board 4. In this embodiment, the self-tapping screws 6 are FL self-tapping screws 6. Subsequently, joint filling is carried out to complete the construction of the concrete thermal insulation layer of the secondary lining 1 of the opening section in the alpine region.

[0034] The steps of installing the keel 5 include: S5-1: Orient the opening direction of the keel 5 towards the thermal insulation board 4, and press the keel 5 so that the U-shaped member 2 passes through the keel 5 and the keel 5 is embedded in the thermal insulation board 4; S5-2: Bend the wing plates of the U-shaped member 2 towards each other, so that the wing plates of the U-shaped member 2 cross and fasten the keel 5 to complete the installation of the keel 5.

[0035] In this embodiment, the material of the thermal insulation board 4 is phenolic foam material, and the thickness is not less than fifty millimeters. Compared with other solutions, the closed-cell structure of phenolic foam makes it have low air permeability, which can reduce the heat loss caused by the convection of the gas inside the airway and the gas outside the thermal insulation board 4 when the airway air pressure changes, and affect the air pressure inside the airway, and then the air flow inside the airway, affecting the accuracy of the data collected by the monitoring component 8. At the same time, it can also prevent external water vapor from entering the airway, forming moisture retention, further affecting the accuracy of the data collected by the monitoring component 8, and causing erosion of the U-shaped member 2, etc., affecting the service life of the thermal insulation layer.

[0036] Embodiment 2 As shown in the appendix Figure 6 As shown, the difference from the above embodiment is that: in S4, the monitoring component 8 includes a conductive rod 81 and a number of storage batteries. The conductive rod 81 is made of metal. An insulating cover 82 is sleeved on any end of the conductive rod 81. The insulating cover 82 is adhesively fixed to the airway side wall, and a number of conductive strips 83 are embedded and adhesively fixed on the insulating cover 82. The number of storage batteries electrically connected to the conductive strips 83 is different. The conductive rod 81 is electrically connected to a current sensor. The current sensor is used to collect the current information passing through the conductive rod 81. The controller determines the position of the conductive strip 83 electrically connected to the conductive rod 81 according to the current information, and obtains the gas flow direction inside the airway according to the position of the conductive strip 83.

[0037] In this embodiment, the temperature acquisition component includes an infrared temperature sensor and a multi-axis motion platform. In this embodiment, the model of the multi-axis motion platform is PY69358. The infrared sensor is fixedly connected to the multi-axis motion platform by bolts. The multi-axis fixed platform is installed inside the through hole.

[0038] The controller, the infrared temperature sensor, the multi-axis motion platform and the current sensor are all electrically connected to the controller.

[0039] The specific implementation method is as follows: When using this solution, the current sensor continuously collects the current information passing through the conductive rod 81. In the initial state, there is no temperature difference on the surface of the secondary lining 1. At this time, there is no air flow in the air duct, the conductive rod 81 is not affected by external forces, and is in the initial state, not in contact with any conductive strip 83. At this time, the circuit where the current sensor is located is disconnected, and the current information collected by the current sensor is zero. When there is a temperature difference on the surface of the secondary lining 1, at this time, there is a pressure difference at each position of the air duct, and air flow begins to appear. At this time, the air flow drives the conductive rod 81 to tilt. At a certain moment, the conductive rod 81 contacts the conductive strip 83, the circuit is connected, and all the storage batteries electrically connected to the conductive strip 83 are connected to the circuit, and a current is generated in the circuit, that is, current information appears. Since the current of a single storage battery is known and the connection scheme between the storage batteries is known, the controller can judge the number of storage batteries connected to the circuit according to the magnitude of the current information, and then judge the position of the conductive strip 83 in contact with the conductive rod 81, and judge the tilting direction of the conductive rod 81, so as to obtain the direction of gas flow in the air duct. Subsequently, the controller controls the infrared temperature sensor to work, and at the same time controls the multi-axis motion platform to work. Through the multi-axis motion platform, the infrared temperature sensor is driven to rotate, so as to change the position collected by the infrared temperature sensor, and then obtain a set of corresponding temperature information. The controller takes the maximum value in this set of temperature information as the standard value, and controls the electric heating plate 3 at the corresponding position to work. Through the electric heating plate 3, the position with temperature difference is heated, so that the temperature of the heated position reaches the standard value.

[0040] Compared with the previous embodiment, in the design of the conductive rod 81 and the conductive strip 83 in this solution, by increasing the number of conductive strips 83, the range of directions that the monitoring component 8 can monitor can be increased. In the previous solution, to increase the monitoring direction, it was necessary to change the shape of the convex block and increase the number of strain gauges at the same time. Therefore, the cost of a single monitoring direction in this solution gradually decreases as the number of detection directions increases. At the same time, since the sensors in this solution can be set outside the air duct, it is convenient for inspection and maintenance after construction, reducing the maintenance steps and maintenance costs of the later maintenance personnel. And the sensors in this solution are less affected by temperature, and the collected data is more accurate.

[0041] At the same time, since the thermal insulation layer uses phenolic foam material, the internal bubbles are independent. When external mechanical vibration is transmitted to the inside of the air duct, the heat insulation board 4 can absorb the vibration energy through the deformation of the cell wall, thereby reducing the influence of mechanical vibration and the like on the monitoring component 8 after construction.

[0042] In this solution, the infrared temperature sensor is combined with a multi-axis motion platform. Compared with the previous embodiment, the number of sensors has decreased significantly, which is beneficial to reducing the cost of the solution. At the same time, since the infrared temperature sensor can achieve non-contact temperature measurement, this solution can be designed outside the insulation layer, facilitating post-operation monitoring, maintenance, or replacement. And through the continuous operation of the infrared temperature sensor in this solution, temperature information at multiple positions can be obtained. Compared with the previous embodiment, the data acquisition coverage area is wider and less affected by situations such as sudden temperature changes.

[0043] At the same time, after the operation, the operator can also use the infrared temperature sensor to further judge the airtightness of the insulation layer, that is, by judging whether there is abnormal data in a set of collected temperature information. For example, if there is a sudden drop or increase in temperature in a certain area in this set of temperature information, there may be a crack at that place, causing heat convection between that position and the outside world.

[0044] Embodiment 3 The difference from the above embodiment is that in S1, a photovoltaic solar power generation component (not shown in the figure) is selected. According to the geographical conditions of the cave entrance, the position with the longest sunshine duration is selected to install the photovoltaic solar power generation component, and the photovoltaic solar power generation component is used to supply power to the electric heating plate 3, the monitoring component 8, the temperature acquisition component, and the control component.

[0045] The photovoltaic solar power generation component includes a photovoltaic cell, a solar panel, and an inverter. The electric heating plate 3, the monitoring component 8, the temperature acquisition component, and the control are all electrically connected to the photovoltaic cell. The temperature acquisition component is also used to collect the temperature of the solar panel. The control component judges the current sunshine situation according to the temperature of the solar panel and controls the operation of the electric heating plate 3 according to the current sunshine situation.

[0046] The specific implementation method is as follows: When using this solution, according to the geographical conditions of the cave entrance, the position with the longest sunshine duration is selected to install the solar panel to increase the power generation of the photovoltaic solar power generation component. This solution makes full use of the characteristics of strong radiation and abundant sunshine in alpine regions through the photovoltaic solar power generation component to independently supply power to the structure for active insulation, reducing energy consumption after the operation.

[0047] In this process, through the temperature acquisition component, such as the controller intermittently controlling the operation of the infrared temperature sensor, and driving the infrared temperature sensor to rotate through the multi-axis fixed platform to collect the temperature of the solar panel, so as to obtain the temperature of the solar panel. Since there is an obvious temperature difference between when the solar panel is exposed to sunlight and when it is not, the controller can judge whether the position of the hole is in the sunlight state according to the temperature change. When the position of the hole is in the sunlight state, and at this time there is a temperature difference on the surface of the secondary lining 1, after the controller controls the temperature acquisition component and other operations and selects the standard value, the standard value may be a relatively high value at this time, and the relatively high temperature is likely to cause the insulation board 4 to expand, thereby affecting the structural stability.

[0048] At this time, the controller selects the average value in this group of temperature information as the standard value for subsequent heating treatment. Compared with only heating the negative temperature position to the positive temperature, this solution can avoid a large temperature difference on the secondary lining 1, resulting in inconsistent shrinkage and expansion at each position of the secondary lining 1 and affecting the structural stability.

[0049] The specific embodiments described above have further elaborated on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for constructing a secondary lining concrete thermal insulation layer at a tunnel entrance in a high-cold region, characterized in that: S1: Selecting a heat preservation board (4), a keel (5), a fiber reinforcement device board (7) and a plurality of electric heating plates (3), then cleaning and decontaminating the surface of the secondary lining (1), and repairing defective parts of the surface of the secondary lining (1); S2: Select a number of U-shaped components (2), measure and lay out on the surface of the secondary lining (1), and install the U-shaped components (2); S3: The electric heating plate (3) is fixed by the wing plate of the U-shaped member (2), and then the heat preservation plate (4) is installed and pressed so that the wing plate of the U-shaped member (2) enters into the heat preservation plate (4): S4: opening an air passage in the thermal insulation layer, and installing a monitoring component (8) in the air passage, and then installing a temperature collection component and a control component inside the hole, and electrically connecting the monitoring component (8), the temperature collection component and the electric heating plate (3) to the control component; The monitoring component (8) is used to collect the flow direction of gas in the airway, the control component determines the position where the temperature difference occurs in the insulation layer according to the gas flow plan, and controls the temperature collection component to collect the temperature at the position where the temperature difference occurs, obtains a group of temperature information, selects the maximum value in the group of temperature information as the standard value, and then controls the electric heating plate (3) to work according to the temperature information until the temperature information at the position where the temperature difference occurs reaches the standard value; S5: The keel (5) is fixed by the U-shaped member (2), and the fiber reinforcement device plate (7) is installed on the side of the keel (5) away from the insulation board (4) using self-tapping screws (6), and then the joint is filled to complete the construction of the concrete thermal insulation layer of the secondary lining (1) of the tunnel section in the high-cold area.

2. The method for constructing a secondary lining concrete heat insulation layer in a tunnel section in a high-cold region according to claim 1, characterized in that: In S1, a photovoltaic solar power generation component is selected, and according to the geographical conditions of the cave entrance, a location with the longest sunshine duration is selected to install the photovoltaic solar power generation component, and the photovoltaic solar power generation component is used to supply power to the electric heating plate (3), the monitoring component (8), the temperature collection component and the control component.

3. The method for constructing a secondary lining concrete heat insulation layer in a tunnel section in a high-cold region according to claim 1, characterized in that: The monitoring component (8) in S4 comprises a conductive rod (81) and a plurality of storage batteries, the conductive rod (81) being made of metal, an insulating cover (82) being sleeved on any one end of the conductive rod (81), the insulating cover (82) being fixedly connected to the side wall of the airway, and a plurality of conductive strips (83) being fixedly connected to the insulating cover (82), the number of storage batteries electrically connected to the conductive strips (83) being different, the conductive rod (81) being electrically connected to a current sensor, the current sensor being used to collect current information passing through the conductive rod (81), the conductive strip (83) being used to connect the circuit of the current sensor and the storage battery, the control component determining the position of the conductive strip (83) electrically connected to the conductive rod (81) according to the current information, and obtaining the gas flow direction in the airway according to the position of the conductive strip (83).

4. The method for constructing a secondary lining concrete heat insulation layer in a tunnel section in a high-cold region according to claim 1, characterized in that: The temperature acquisition component comprises an infrared temperature sensor and a multi-axis motion platform, the infrared sensor is fixedly connected to the multi-axis motion platform, and the multi-axis fixed platform is installed inside the through opening.

5. The method for constructing a secondary lining (1) concrete heat insulation layer of a tunnel entrance section in a high-cold region according to claim 1, characterized in that: In S2, the U-shaped components (2) are arranged in a matrix.

6. The method for constructing a secondary lining (1) concrete heat insulation layer of a tunnel entrance section in a high-cold region according to claim 1, characterized in that: The step of installing the insulation board (4) in S3 includes: S3-1: cutting the insulation board (4) according to the second lining size; S3-2: pressing the insulation plate (4) so ​​that the wing plate of the U-shaped component (2) is embedded in the insulation plate (4), and continuing to push the insulation plate (4) so ​​that the side of the insulation plate (4) close to the electric heating plate (3) is in contact with the electric heating plate (3).

7. The method for constructing a secondary lining (1) concrete heat insulation layer of a tunnel entrance section in a high-cold region according to claim 1, characterized in that: The steps of installing the keel (5) in S5 include: S5-1: the opening direction of the keel (5) is directed toward the thermal insulation board (4), and the keel (5) is pressed, so that the U-shaped component (2) passes through the keel (5), and the keel (5) is embedded in the thermal insulation board (4); S5-2: bend the wing plates of the U-shaped member (2) in a direction approaching each other, so that the wing plates of the U-shaped member (2) cross-lock with the keel (5), thereby completing the installation of the keel (5).

8. The method for constructing a secondary lining (1) concrete heat insulation layer of a tunnel entrance section in a high-cold region according to claim 1, characterized in that: After the joints in S5 are filled, a vacuum pump is used to generate negative pressure in the thermal insulation layer, and the changes in the air pressure in the thermal insulation layer are continuously monitored. Only when the difference in air pressure change within the set time is less than the preset value, the air pressure in the thermal insulation layer is returned to atmospheric pressure through the vacuum pump.

9. The method for constructing a secondary lining (1) concrete heat insulation layer of a tunnel entrance section in a high-cold region according to claim 1, characterized in that: The material of the insulation board (4) in S1 is polyphenolic foam material, and the thickness is not less than fifty millimeters.

10. The method for constructing a secondary lining (1) concrete heat insulation layer of a tunnel entrance section in a high-cold region according to claim 2, characterized in that: The photovoltaic solar power generation component comprises a photovoltaic cell, a solar panel and an inverter. The temperature collection component is also used to collect the temperature of the solar panel. The control component determines the current sunshine conditions according to the temperature of the solar panel and controls the operation of the electric heating panel (3) according to the current sunshine conditions.

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