Cold absorption and melting prevention construction method for frozen soil tunnel

Abstract

The invention provides a frozen soil tunnel cold absorption and melting prevention construction method, which belongs to the technical field of tunnel cold insulation, and comprises the following steps: drilling a plurality of heat exchange holes in the periphery of a tunnel to be constructed along the preset length direction of the tunnel, and inserting heat exchange cylinders into the heat exchange holes. Slope excavation is conducted on the tunnel area, and a plurality of communicating holes communicating with the heat exchange holes are drilled in the side wall of an excavated hole; a communicating pipe is inserted into the communicating hole, and a plurality of heat conduction pipes are laid on the side wall of the hole; two ends of the communicating pipe are respectively communicated with the heat conduction pipe and the heat exchange cylinder to form a sealed circulation path; the liquid continuously flows in the circulation path, so that the continuous temperature control on the tunnel is realized; and a heat preservation layer is laid on the finally-formed lining structure. According to the cold absorption and melting prevention construction method for the frozen soil tunnel, melting of frozen soil liquid is avoided, the stability of the whole tunnel structure is guaranteed, safety is improved, and meanwhile the whole method is convenient to operate and low in cost.

Description

Technical Field

[0001] This invention belongs to the field of tunnel insulation technology, and more specifically, relates to a construction method for preventing thawing and absorbing cold in frozen soil tunnels. Background Technology

[0002] After the excavation of a permafrost tunnel, the original thermal equilibrium is disrupted, causing the permafrost surrounding rock to thaw and forming a thaw zone. During tunnel operation, the temperature inside the tunnel varies with the seasons, causing the permafrost at the lining structure to thaw, leading to problems such as water leakage and structural frost heave damage. Promoting the rapid refreezing of the permafrost surrounding rock and maintaining a stable frozen state is crucial for the long-term stable service of permafrost tunnels.

[0003] The traditional method involves laying an insulation layer on the inside of the lining structure. This can reduce the heat absorbed by the lining structure to some extent. However, the thermal insulation capacity of the insulation layer decreases over time, and it cannot achieve 100% heat shielding. This means that when the temperature inside the tunnel is high, water seepage can still occur, and once water seeps into the insulation layer, its insulation effect will be greatly reduced.

[0004] It should be noted that tunnels formed by excavating through permafrost layers are located within permafrost, where the internal temperature remains relatively constant due to the high degree of airtightness, meaning the tunnel remains at a low temperature for extended periods. Therefore, achieving long-term and effective temperature control of the tunnel at a relatively low cost to ensure its overall stability is a pressing issue. Summary of the Invention

[0005] The purpose of this invention is to provide a construction method for preventing thawing in frozen soil tunnels, which aims to solve the problems of frozen soil tunnels being prone to melting and leakage due to the inability to maintain a constant temperature and their poor safety.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a construction method for absorbing cold and preventing thawing in frozen soil tunnels, comprising: Multiple heat exchange holes are drilled around the periphery of the tunnel to be constructed along the predetermined length of the tunnel, and a heat exchange cylinder is inserted into the heat exchange holes. The tunnel area is excavated with a slope, and multiple connecting holes that communicate with the heat exchange holes are drilled on the side wall of the excavated tunnel; connecting pipes are inserted into the connecting holes, and multiple heat-conducting pipes are laid on the side wall of the tunnel. The two ends of the connecting pipe are respectively connected to the heat-conducting pipe and the heat exchange cylinder to form a sealed circulation path; Continuous temperature control of the tunnel is achieved by allowing the liquid to flow continuously within the circulation path; an insulation layer is then laid on the final lining structure.

[0007] In one possible implementation, the process further includes, before inserting the heat exchange cylinder into the heat exchange hole: A reinforcing tube is inserted into the heat exchange hole, and the reinforcing tube serves as external protection for the heat exchange cylinder; The reinforcing pipes are used to reinforce the outer perimeter of the tunnel, thereby improving the stability of the tunnel.

[0008] In one possible implementation, after inserting the reinforcing tube into the heat exchange hole, the following is further included: Heating the reinforcing tube melts and discharges the solid liquid inside the frozen soil outside the reinforcing tube, thereby widening the gap between the reinforcing tube and the heat exchange hole.

[0009] In one possible implementation, after widening the gap between the reinforcing tube and the heat exchange hole, the following is further included: The reinforcing tube is pulled out, and multiple extension holes extending outward from the heat exchange hole are drilled on the side wall of the enlarged heat exchange hole. The multiple extension holes are arranged circumferentially along the heat exchange hole.

[0010] In one possible implementation, after drilling a plurality of extension holes extending outward from the heat exchange hole on the sidewall of the enlarged heat exchange hole, the method further includes: Clean the impurities in the heat exchange holes and reinforcing tubes; inject sizing material into the outside of the reinforcing tubes, filling the heat exchange holes and the extension holes; after the sizing material has solidified, it and the reinforcing tubes together form a reinforcing structure to stabilize the tunnel; The heat exchange efficiency is improved by increasing the heat exchange area between the reinforcing tube and the outside environment by using the shaping material in the extended hole.

[0011] In one possible implementation, inserting the reinforcing tube into the heat exchange hole includes: Multiple stress sleeves are fitted along the length of the reinforcing tube to obtain information fed back by the multiple stress sleeves; The stress changes and stability of the tunnel's outer structure are monitored in real time using multiple stress sleeves.

[0012] In one possible implementation, inserting the heat exchange cylinder into the heat exchange hole includes: Multiple heat exchange cylinders, sealed at both ends, are placed sequentially inside the reinforcing tube; The end of the connecting pipe is inserted into the sealing hole on the side wall of the heat exchange cylinder, and the gap between the connecting pipe and the sealing hole is sealed by the sealing ring in the sealing hole.

[0013] In one possible implementation, inserting the heat exchange cylinder into the heat exchange hole includes: Lower the temperature of the heat exchange cylinder, and then insert the heat exchange cylinder into the reinforcing tube; After the temperature of the heat exchange cylinder increases, the heat exchange cylinder comes into close contact with the reinforcing tube. This improves the heat transfer efficiency between the heat exchange cylinder and the reinforcing tube, and also enhances the reinforcing tube's resistance to impact deformation through the heat exchange cylinder.

[0014] In one possible implementation, after inserting the connecting tube into the connecting hole, the following is further included: Casting is performed between the connecting hole and the connecting pipe, and after curing, the connecting pipe serves as a reinforcing anchor for the tunnel.

[0015] In one possible implementation, the step of connecting both ends of the connecting pipe to the heat-conducting pipe and the heat exchange cylinder respectively to form a sealed circulation path includes: A groove is constructed on the sidewall of the tunnel to hold the heat-conducting pipe; Multiple heat-conducting pipes are bent and connected to achieve heat exchange coverage of the tunnel; A circulation pump is installed in the circulation path to achieve the circulation flow of the liquid.

[0016] The beneficial effects of the frozen soil tunnel cooling and thawing prevention construction method provided by this invention are as follows: Compared with the prior art, the frozen soil tunnel cooling and thawing prevention construction method of this invention first drills multiple heat exchange holes along the predetermined length of the tunnel on the periphery of the tunnel to be constructed, and inserts heat exchange cylinders into the heat exchange holes. Multiple connecting holes communicating with the heat exchange holes are drilled on the sidewall of the excavated tunnel, and then connecting pipes are inserted. A sealed circulation path is formed by connecting both ends of the connecting pipe to a heat-conducting pipe and a heat exchange cylinder, respectively.

[0017] In practical applications, because the liquid flows continuously in the circulation channel, the temperature inside the tunnel eventually becomes the same as the temperature outside the tunnel, while the temperature outside the tunnel is relatively constant and lower. This achieves temperature stability in the tunnel, which prevents the freezing liquid from melting, ensures the stability of the entire tunnel structure, and improves safety. At the same time, the whole method is easy to operate and has low cost. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart of a construction method for preventing thawing and cooling in frozen soil tunnels provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0021] Please see Figure 1 The present invention will now describe the construction method for preventing thawing and cooling in frozen soil tunnels. The construction method for preventing thawing and cooling in frozen soil tunnels includes: Drill multiple heat exchange holes along the predetermined length of the tunnel on the outer perimeter of the tunnel to be constructed, and insert the heat exchange cylinder into the heat exchange holes; The tunnel area is excavated with a slope, and multiple connecting holes connected to heat exchange holes are drilled on the side wall of the excavated tunnel; connecting pipes are inserted into the connecting holes, and multiple heat conduction pipes are laid on the side wall of the tunnel. The two ends of the connecting pipe are connected to the heat-conducting pipe and the heat exchange cylinder respectively to form a sealed circulation path; By continuously circulating the liquid within the circulation path, continuous temperature control of the tunnel is achieved; an insulation layer is then laid on the final lining structure.

[0022] The beneficial effects of the frozen soil tunnel cooling and thawing prevention construction method provided by this invention are as follows: Compared with the prior art, the frozen soil tunnel cooling and thawing prevention construction method of this invention first drills multiple heat exchange holes along the predetermined length of the tunnel on the periphery of the tunnel to be constructed, and inserts heat exchange cylinders into the heat exchange holes. Multiple connecting holes communicating with the heat exchange holes are drilled on the sidewall of the excavated tunnel, and then connecting pipes are inserted. A sealed circulation path is formed by connecting both ends of the connecting pipe to a heat-conducting pipe and a heat exchange cylinder, respectively.

[0023] In practical applications, because the liquid flows continuously in the circulation channel, the temperature inside the tunnel eventually becomes the same as the temperature outside the tunnel, while the temperature outside the tunnel is relatively constant and lower. This achieves temperature stability in the tunnel, which prevents the freezing liquid from melting, ensures the stability of the entire tunnel structure, and improves safety. At the same time, the whole method is easy to operate and has low cost.

[0024] In some embodiments of the construction method for absorbing cold and preventing thawing in frozen soil tunnels provided in this application, the method further includes the following steps before inserting the heat exchange cylinder into the heat exchange hole: A reinforcing tube is inserted into the heat exchange hole to serve as external protection for the heat exchange cylinder. The tunnel's perimeter is reinforced by reinforcing pipes, thereby improving the tunnel's stability.

[0025] After the reinforcement pipe is positioned, it can achieve stable heat exchange between the surrounding environment and the heat exchange cylinder, and it can also reinforce the outside of the tunnel.

[0026] After the reinforcing tube is inserted into the heat exchange hole, it is fixed to ensure its stable position. Then, the heat exchange cylinder is inserted into the reinforcing tube, and sealing measures are used to ensure the airtightness between the heat exchange cylinder and the reinforcing tube, preventing external air or other substances from entering and affecting the heat exchange effect. A suitable liquid is injected into the circulation path, the circulation system is started, and the flow of the liquid and temperature changes within the circulation path are observed. As the liquid continues to flow, the temperature inside the tunnel gradually approaches the temperature outside the tunnel. During this process, temperature data is closely monitored, and the parameters of the circulation system, such as liquid flow rate and circulation frequency, are adjusted in a timely manner according to temperature changes to ensure that the tunnel temperature remains stable within a suitable range, effectively preventing the melting of the frozen soil and ensuring the stability and safety of the entire tunnel structure. Simultaneously, all parameters and equipment operation are continuously monitored throughout the construction process, and any problems that may arise are addressed promptly to ensure the smooth implementation of the construction method. This further verifies the reliability and effectiveness of the frozen soil tunnel cold absorption and thaw prevention construction method in practical applications, providing valuable experience and reference for subsequent similar projects.

[0027] In some embodiments of the construction method for absorbing cold and preventing thawing in frozen soil tunnels provided in this application, after inserting the reinforcing pipe into the heat exchange hole, the method further includes: Heating the reinforcing tube melts and drains the solid liquid inside the frozen soil outside the tube, thus widening the gap between the reinforcing tube and the heat exchange hole.

[0028] Only after the liquid is drained and the sizing agent is poured can a tight connection between the reinforcing pipe and the surrounding environment be ensured to prevent gaps. This also ensures effective heat conduction, because gaps would reduce the cooling effect on the tunnel walls.

[0029] Specific heating methods can employ suitable means such as resistance heating, controlling the heating temperature and time to ensure the solid-liquid mixture fully melts and drains smoothly. During the heating process, the melting of the solid-liquid mixture within the frozen soil and the changes in the gap between the reinforcing pipe and the heat exchange hole must be closely monitored. Heating should be stopped once the gap has widened to a suitable extent. At this point, the spatial state between the reinforcing pipe and the heat exchange hole is more ideal, laying a good foundation for subsequent construction operations. In subsequent construction, continuous inspection and maintenance of the connection between the reinforcing pipe and the surrounding environment are necessary to ensure its tightness always meets requirements, thereby guaranteeing efficient and stable heat transfer and providing reliable support for the cold absorption and thaw prevention of the frozen soil tunnel.

[0030] In some embodiments of the construction method for absorbing cold and preventing thawing in frozen soil tunnels provided in this application, after widening the gap between the reinforcing pipe and the heat exchange hole, the method further includes: Remove the reinforcing tube and drill multiple extension holes extending outward from the heat exchange hole on the side wall of the enlarged heat exchange hole. The multiple extension holes are arranged circumferentially along the heat exchange hole.

[0031] The extension holes are elongated holes, machined using a rotary cutter. Ultimately, multiple extension holes connect to a single heat exchange hole, resembling the sun and its surrounding rays. The extension holes can be seen as an outward extension structure from the heat exchange hole. By drilling multiple extension holes into the sidewall of the heat exchange hole, the heat exchange area is increased, allowing for more efficient heat exchange between the permafrost and the outside environment. These extension holes are arranged circumferentially along the heat exchange hole, expanding the heat exchange path in all directions, much like the rays around the sun. After drilling the extension holes, materials with high thermal conductivity can be filled inside, depending on actual needs, to further improve heat exchange efficiency. For example, a specially formulated thermally conductive gel can be filled, which better conducts heat, accelerating heat dissipation within the permafrost tunnel and thus more effectively preventing permafrost thawing. Simultaneously, during subsequent construction, the filling material must be protected from external damage to ensure the stable operation of the entire cold absorption and thawing prevention system. A rotary cutter can machine two extension holes at a time.

[0032] In some embodiments of the construction method for preventing thawing and cooling in frozen soil tunnels provided in this application, after drilling multiple extension holes extending outward from the heat exchange hole on the sidewall of the enlarged hole, the method further includes: Clean the impurities in the heat exchange holes and reinforcing tubes; inject sizing material into the outside of the reinforcing tubes, filling the heat exchange holes and extension holes; after the sizing material has solidified, it works together with the reinforcing tubes to form a reinforcing structure to stabilize the tunnel. By using the shaped material inside the extension hole to increase the heat exchange area between the reinforcing tube and the outside, the heat exchange efficiency can be improved.

[0033] After completing the above steps, the reinforced structure can be inspected. Specifically, professional testing equipment is used to check the stability of the reinforced structure formed by the reinforcing tube and the shaped material, looking for any looseness or loose connections. If problems are found in certain areas, timely repair and reinforcement are carried out to ensure that the reinforced structure can function stably and reliably for a long time, providing reliable support for the tunnel.

[0034] Simultaneously, the temperature changes of the permafrost surrounding the tunnel are continuously monitored. Temperature sensors are installed at different locations within the tunnel to collect temperature data in real time. Based on the temperature changes, the heat exchange effect of the reinforced structure is analyzed to determine if it meets expectations. If a decrease in heat exchange efficiency is detected, further inspection can be conducted to check for blockages or damage to the shaping material within the extension holes. Appropriate measures can then be taken promptly for adjustment and optimization to ensure that the permafrost tunnel cold absorption and thaw prevention construction method can continuously and effectively maintain the stability of the tunnel and prevent safety hazards caused by permafrost thawing.

[0035] In addition, regular maintenance and upkeep of the reinforced structure are essential. Clean any debris that may be adhering to the surface of the reinforced pipes to prevent it from affecting heat exchange efficiency. Inspect the shaped material and, if necessary, repair or reinforce it locally to ensure the entire reinforced structure remains in good working condition. Furthermore, adjust and optimize some parameters in the construction methods in a timely manner according to the tunnel's usage and changes in the surrounding environment to adapt to different working conditions and further improve the safety and stability of the permafrost tunnel.

[0036] In some embodiments of the construction method for absorbing cold and preventing thawing in frozen soil tunnels provided in this application, inserting reinforcing pipes into the heat exchange holes includes: Multiple stress sleeves are installed along the length of the reinforcing tube, and information fed back from the multiple stress sleeves is obtained; Multiple stress sleeves are used to monitor the stress changes and stability of the tunnel's external structure in real time.

[0037] When stress changes exceed the preset range, an early warning mechanism is immediately activated, sending alarm signals to construction personnel to remind them to take appropriate measures, such as suspending construction or adjusting construction parameters, to ensure the stability of the tunnel's outer structure. Simultaneously, based on the information from the stress chamber feedback, the trend of stress changes is analyzed. If a sustained increase in stress is found to pose a risk of instability to the tunnel's outer structure, professional technicians are promptly organized to conduct an assessment and develop targeted reinforcement plans, such as adding support structures or adjusting the operating parameters of the cooling absorption system. By optimizing construction methods and strengthening protective measures, the safety and stability of the cooling absorption and thawing prevention construction of the permafrost tunnel are ensured, avoiding serious consequences such as tunnel structural damage caused by stress issues. This allows for the smooth progress of the entire project and ensures that the project quality meets the expected standards.

[0038] In some embodiments of the construction method for preventing thawing and cooling in frozen soil tunnels provided in this application, inserting the heat exchange cylinder into the heat exchange hole includes: Multiple heat exchange cylinders with sealed ends are placed inside the reinforcing tube in this manner; The end of the connecting pipe is inserted into the sealing hole on the side wall of the heat exchange cylinder, and the gap between the connecting pipe and the sealing hole is sealed by the sealing ring inside the sealing hole.

[0039] A pressure test is required after installation to prevent leaks.

[0040] During the pressure test, first close all valves connected to the heat exchanger to ensure the system is in a closed state. Then, slowly inject high-pressure gas or liquid into the system using the pressure testing equipment, observing the pressure changes. When the pressure reaches the specified test pressure value, maintain it for a period of time, closely monitoring for any pressure drop. If the pressure drops, it indicates a leak, requiring careful inspection of all connections, including the seals between the heat exchanger and the connecting pipe, and the connection points between the reinforcing pipe and the heat exchanger, to locate and repair any leaks. Only after the pressure test is passed and no leaks are confirmed can subsequent construction steps proceed to ensure the normal operation and effectiveness of the entire frozen soil tunnel's cold absorption and thaw prevention system.

[0041] In some embodiments of the construction method for preventing thawing and cooling in frozen soil tunnels provided in this application, inserting the heat exchange cylinder into the heat exchange hole includes: Lower the temperature of the heat exchange cylinder, and then insert the heat exchange cylinder into the reinforcing tube; After the heat exchange cylinder temperature is increased, the heat exchange cylinder and the reinforcing tube come into close contact. On the one hand, this improves the heat transfer efficiency between the heat exchange cylinder and the reinforcing tube, and on the other hand, it enhances the reinforcing tube's resistance to impact deformation through the heat exchange cylinder.

[0042] Furthermore, after inserting the heat exchanger cylinder into the reinforcing pipe, the connection point between the two can be sealed to prevent external heat from entering. Subsequently, the refrigeration equipment is activated, continuously absorbing heat from the surrounding permafrost tunnel through the heat exchanger cylinder, lowering the permafrost temperature and enhancing its stability. Simultaneously, designated personnel regularly monitor the temperature changes of the heat exchanger cylinder and the temperature of the permafrost, adjusting the operating parameters of the refrigeration equipment in a timely manner based on the monitoring data to ensure stable and efficient cooling. When significant fluctuations occur in the ambient temperature of the permafrost tunnel, the temperature trend is analyzed promptly, and corresponding measures are taken in advance, such as increasing or decreasing the number of heat exchanger cylinders or adjusting the refrigeration power, to meet the permafrost thaw prevention requirements under different environmental conditions. Throughout the entire construction and operation process, all data, including the insertion depth of the heat exchanger cylinder, temperature changes, and permafrost temperature changes, are strictly recorded to facilitate subsequent evaluation of the construction effect and to summarize experience, providing a reliable reference for similar permafrost tunnel cooling and thaw prevention projects.

[0043] In some embodiments of the construction method for absorbing cold and preventing thawing in frozen soil tunnels provided in this application, after inserting a connecting pipe into the connecting hole, the method further includes: Casting is carried out between the connecting hole and the connecting pipe, and after curing, the connecting pipe serves as a reinforcing anchor for the tunnel.

[0044] The above-mentioned configuration allows the connecting pipe of this application to serve as both an anchor for reinforcement and a channel for liquid flow.

[0045] During actual construction, it is crucial to ensure that the insertion depth of the connecting pipe into the connecting hole meets design requirements to guarantee its anchoring effect. Simultaneously, the selection of the pouring material is also critical; suitable materials with good curing properties and adhesion must be chosen based on the specific geological conditions and engineering needs of the permafrost tunnel. During pouring, careful compaction is essential to avoid voids or gaps that could affect the strength and stability of the connecting pipe as a reinforcing anchor. After the pouring material has cured, the performance of the connecting pipe as a reinforcing anchor should be tested, such as through pull-out tests, to verify whether it meets the design requirements for tunnel reinforcement. Only when the test results meet the standards can subsequent construction procedures proceed. During subsequent tunnel construction, close monitoring of the connecting pipe's operation as a liquid flow channel is necessary to ensure smooth liquid flow within the pipe, achieving the effect of cold absorption and thaw prevention. Regular inspection and maintenance of the connecting pipe and related cold absorption and thaw prevention systems are also essential to promptly identify and address any potential problems, ensuring the stability and safety of the permafrost tunnel. As tunnel construction progresses, the operating parameters of the cold absorption and thawing prevention system, such as the flow rate and temperature of the liquid, are adjusted according to the characteristics of the permafrost in different sections and the construction schedule. This is to adapt to the constantly changing construction environment, keep the tunnel in a stable state, and provide a solid guarantee for the successful completion of the entire project.

[0046] In some embodiments of the construction method for preventing thawing and cooling in frozen soil tunnels provided in this application, the method of connecting both ends of the connecting pipe to a heat-conducting pipe and a heat exchange cylinder respectively to form a sealed circulation path includes: A groove was constructed on the tunnel sidewall to hold the heat pipes; Multiple heat pipes are bent and connected to achieve heat exchange coverage of the tunnel; A circulation pump is installed in the circulation path to achieve the circulation flow of the liquid.

[0047] After the heat pipe is fixed, a steel cage needs to be tied to seal the heat pipe inside the lining structure.

[0048] First, when tying the reinforcing cage, ensure its dimensions are compatible with the lining structure and that the spacing of the reinforcing bars is uniform and reasonable to guarantee the strength and stability of the cage. Next, carefully place the heat-conducting pipes in their designated positions within the reinforcing cage, ensuring they are tightly enclosed. This allows for better sealing within the lining structure during subsequent concrete pouring. During placement, check for any gaps between the heat-conducting pipes and the reinforcing cage that might affect the sealing effect; adjust any gaps promptly. Then, prepare to pour the lining concrete. The concrete mix must strictly adhere to the design requirements to ensure appropriate strength, durability, and workability. During pouring, use layered vibration to ensure the concrete is fully compacted, filling the space between the reinforcing cage and the tunnel wall, firmly sealing the heat-conducting pipes within the lining structure. During vibration, avoid direct contact between the vibrator and the heat-conducting pipes to prevent damage. After pouring, the lining concrete must be cured and kept moist to promote strength development and ensure that the sealed heat pipes can function stably within the lining structure for a long period. Simultaneously, the condition of the lining structure must be closely monitored during the curing period. If cracks or other abnormalities are found, appropriate measures must be taken promptly to ensure the integrity and reliability of the entire frozen soil tunnel's cold absorption and thaw prevention system.

[0049] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A construction method for preventing thawing and cooling in frozen soil tunnels, characterized in that, include: Multiple heat exchange holes are drilled around the periphery of the tunnel to be constructed along the predetermined length of the tunnel, and a heat exchange cylinder is inserted into the heat exchange holes. The tunnel area is excavated with a slope, and multiple connecting holes that communicate with the heat exchange holes are drilled on the side wall of the excavated tunnel; connecting pipes are inserted into the connecting holes, and multiple heat-conducting pipes are laid on the side wall of the tunnel. The two ends of the connecting pipe are respectively connected to the heat-conducting pipe and the heat exchange cylinder to form a sealed circulation path; Continuous temperature control of the tunnel is achieved by allowing the liquid to flow continuously within the circulation path; an insulation layer is then laid on the final lining structure.

2. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 1, characterized in that, Before inserting the heat exchange cylinder into the heat exchange hole, the method further includes: A reinforcing tube is inserted into the heat exchange hole, and the reinforcing tube serves as external protection for the heat exchange cylinder; The reinforcing pipes are used to reinforce the outer perimeter of the tunnel, thereby improving the stability of the tunnel.

3. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 2, characterized in that, After the reinforcing tube is inserted into the heat exchange hole, the following is also included: Heating the reinforcing tube melts and discharges the solid liquid inside the frozen soil outside the reinforcing tube, thereby widening the gap between the reinforcing tube and the heat exchange hole.

4. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 3, characterized in that, After widening the gap between the reinforcing tube and the heat exchange hole, the method further includes: The reinforcing tube is pulled out, and multiple extension holes extending outward from the heat exchange hole are drilled on the side wall of the enlarged heat exchange hole. The multiple extension holes are arranged circumferentially along the heat exchange hole.

5. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 4, characterized in that, After drilling a plurality of extension holes extending outward from the heat exchange hole on the sidewall of the enlarged hole, the method further includes: Clean the impurities in the heat exchange holes and reinforcing tubes; inject sizing material into the outside of the reinforcing tubes, filling the heat exchange holes and the extension holes; after the sizing material has solidified, it and the reinforcing tubes together form a reinforcing structure to stabilize the tunnel; The heat exchange efficiency is improved by increasing the heat exchange area between the reinforcing tube and the outside environment by using the shaping material in the extended hole.

6. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 2, characterized in that, The insertion of the reinforcing tube into the heat exchange hole includes: Multiple stress sleeves are fitted along the length of the reinforcing tube to obtain information fed back by the multiple stress sleeves; The stress changes and stability of the tunnel's outer structure are monitored in real time using multiple stress sleeves.

7. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 2, characterized in that, The step of inserting the heat exchange cylinder into the heat exchange hole includes: Multiple heat exchange cylinders, sealed at both ends, are sequentially placed inside the reinforcing tube; The end of the connecting pipe is inserted into the sealing hole on the side wall of the heat exchange cylinder, and the gap between the connecting pipe and the sealing hole is sealed by the sealing ring in the sealing hole.

8. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 2, characterized in that, The step of inserting the heat exchange cylinder into the heat exchange hole includes: Lower the temperature of the heat exchange cylinder, and then insert the heat exchange cylinder into the reinforcing tube; After the temperature of the heat exchange cylinder increases, the heat exchange cylinder comes into close contact with the reinforcing tube. This improves the heat transfer efficiency between the heat exchange cylinder and the reinforcing tube, and also enhances the reinforcing tube's resistance to impact deformation through the heat exchange cylinder.

9. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 1, characterized in that, After inserting the connecting tube into the connecting hole, the method further includes: Casting is performed between the connecting hole and the connecting pipe, and after curing, the connecting pipe serves as a reinforcing anchor for the tunnel.

10. The construction method for preventing thawing and cooling in frozen soil tunnels as described in claim 1, characterized in that, The method of connecting both ends of the connecting pipe to the heat-conducting pipe and the heat exchange cylinder respectively to form a sealed circulation path includes: A groove is constructed on the sidewall of the tunnel to hold the heat-conducting pipe; Multiple heat-conducting pipes are bent and connected to achieve heat exchange coverage of the tunnel; A circulation pump is installed in the circulation path to achieve the circulation flow of the liquid.

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