Full permafrost tunnel drainage system based on suction heating

Abstract

The present application relates to the field of cold region tunnel freeze damage prevention and control, and particularly relates to a full permafrost tunnel drainage system based on suction type heating. The system comprises two heat preservation water channels, the heat preservation water channels are arranged along the full length of the two sides of the tunnel, and the four walls of the heat preservation water channels are provided with heat preservation layers; a plurality of drainage systems, wherein the circumferential blind pipes are arranged circumferentially along the tunnel arch wall, the bottoms are communicated with the heat preservation water channels through longitudinal blind pipes and horizontal water guide pipes, and are used for guiding and discharging the seepage water of the surrounding rock, and the plurality of drainage systems are distributed at the set positions of the tunnel; a plurality of heating devices, part of the heating devices are arranged at the top of the tunnel and are used for heating the circumferential blind pipes, and the remaining part of the heating devices are arranged at one side of the heat preservation water channels and are used for heating the set positions of the heat preservation water channels, in other words, the plurality of drainage systems and the plurality of heating devices cooperate to carry out fixed-point concentrated heating on the drainage of the permafrost section in the tunnel hole, the upper limit of the permafrost layer and the shady place of the tunnel entrance, so as to ensure that the tunnel drainage system is unobstructed and is not easy to freeze.

Description

Technical Field

[0001] This invention relates to the field of frost damage prevention and control in tunnels in cold regions, specifically to a drainage system for permafrost tunnels based on suction heating. Background Technology

[0002] Permafrost refers to soil (rock) that has been frozen for two years or more. A tunnel entirely in permafrost is a tunnel whose entire length traverses permafrost, while the entrance section is either permafrost or seasonally frozen. The design principle for the drainage system of a tunnel entirely in permafrost is to minimize disturbance to the permafrost, thereby avoiding large-scale thaw zones that could lead to tunnel subsidence or even collapse. Therefore, in the permafrost sections of a tunnel entirely in permafrost, it is not advisable to use deep central drainage ditches or frost-proof drainage tunnels; shallower, double-sided insulated drainage ditches are preferable. In the seasonally frozen sections of a tunnel entirely in permafrost, insulation layers need to be laid inside the tunnel and on the surface at the entrance during the cold season to keep the seasonally frozen section at the entrance frozen. In this case, the seasonally frozen section at the entrance is equivalent to a permafrost section; therefore, tunnels entirely in permafrost should ideally have double-sided insulated drainage ditches along their entire length. Fully permafrost tunnels are typically located in extremely cold regions, placing exceptionally high demands on the anti-freezing measures of their drainage systems. If the drainage system fails due to freezing, it can lead to serious frost damage that threatens the normal operation of the tunnel, such as water leakage and ice buildup in the tunnel lining, icing at the tunnel floor, and frost heave in the lining. Therefore, it is crucial to develop a well-structured, easy-to-use, and cost-effective drainage system for fully permafrost tunnels to address the problem of drainage system failure due to freezing and blockage.

[0003] Passive insulation and active heating are the main antifreeze measures for tunnel drainage systems in cold regions. Passive insulation involves laying an insulation layer on the surface of the drainage system to prevent freezing, such as insulated water ditches. However, simply laying an insulation layer is insufficient to meet the antifreeze requirements of drainage systems in permafrost tunnels in extremely cold regions, necessitating active heating measures. Active heating includes electric heating and buried heat exchanger pipe heating systems (invention patent, CN112127945A). Traditional electric heating methods prevent water freezing by laying electric heat tracing devices on the tunnel lining surface. Electric heat tracing technology requires numerous supporting facilities, has high energy consumption, and is extremely costly. While buried heat exchanger pipe heating systems can fully utilize geothermal resources and are a very environmentally friendly heating system, this system requires drilling and burying pipes inside the main tunnel, which may encroach on tunnel boundaries and affect the safe operation of the tunnel. Furthermore, to fully utilize geothermal energy, it is often necessary to lay numerous boreholes for pipe burial, which can affect tunnel stability and contradicts the drainage system design principle of minimizing disturbance to permafrost. Therefore, there is a need to invent a drainage system for permafrost tunnels that is structurally sound, easy to apply, and cost-effective. Summary of the Invention

[0004] To address the aforementioned technical problems, this disclosure provides a drainage system for permafrost tunnels based on suction heating.

[0005] The aforementioned drainage system for permafrost tunnels based on suction heating includes:

[0006] Two insulated water ditches are provided along the entire length of both sides of the tunnel, and the walls of the insulated water ditches are all provided with an insulation layer.

[0007] The drainage system includes a circumferential blind pipe, a longitudinal blind pipe, and a transverse water guide pipe. The circumferential blind pipe is arranged circumferentially along the tunnel arch wall. The bottom of the circumferential blind pipe is connected to the longitudinal blind pipe. The transverse water guide pipe is connected to the longitudinal blind pipe and the insulation ditch respectively, and is used to guide and discharge seepage water from the surrounding rock.

[0008] Multiple heating devices are provided, at least some of which are located at the top of the tunnel for heating the circumferential blind pipe, and at least some of which are located on one side of the insulated water ditch for heating a designated position of the insulated water ditch.

[0009] Optionally, there may be multiple circumferential blind pipes, which are spaced apart along the extension direction of the tunnel and distributed at designated locations within the tunnel.

[0010] Optionally, there may be multiple transverse water guide pipes, which are spaced apart along the extension direction of the tunnel.

[0011] Optionally, the heating device includes a connecting pipe, a suction pump, and a suction heater connected in sequence. One end of the connecting pipe is connected to the top of the circumferential blind pipe or the bottom of the insulated water ditch. The suction heater is used to heat the air or water pumped in by the suction pump.

[0012] Both the suction heater and the suction pump are connected to the distribution box.

[0013] Optionally, it also includes a sedimentation well, with the suction heater placed above the sedimentation well, the connecting pipe inserted into the sedimentation well, and the sedimentation well inserted into the insulated water ditch.

[0014] In the above implementation method, the pipe is inserted into the insulation ditch through the hole of the sedimentation well, thereby avoiding damage to the insulation ditch by opening the hole.

[0015] Optionally, the plurality of sedimentation wells are evenly distributed along the tunnel axial direction, and the distance between two adjacent sedimentation wells is 200m to 250m.

[0016] Preferably, the distance between two adjacent sedimentation wells is 200m.

[0017] Optionally, the circumferential blind pipe is installed circumferentially between the initial support and the secondary lining of the tunnel. One end of the transverse water pipe is connected to the insulation ditch, and the other end passes through the tunnel invert and is connected to the bottom of the circumferential blind pipe.

[0018] The longitudinal blind pipe is installed along the entire length of both sides of the bottom of the tunnel, and the longitudinal blind pipe is connected to the joint where it connects with the transverse water guide pipe and the circumferential blind pipe.

[0019] Optionally, the insulation ditch is buried within a range of 1m to 1.5m below the tunnel surface, and the insulation ditch is parallel to the tunnel surface.

[0020] Optionally, it also includes an evacuation platform, which is set along the entire length of both sides of the tunnel and is located above the heating device for maintenance personnel to pass through.

[0021] Optionally, a bracket may also be included, which is fixedly connected to the top of the tunnel to support and secure the heating device.

[0022] The technical solution provided in this disclosure has the following advantages:

[0023] Two insulated water ditches are installed along the entire length of both sides of the tunnel, with insulation layers on all four walls. These ditches are buried underground, and the insulation layer on the outer walls enhances the insulation effect of both sides, reducing the impact of low temperatures in the external soil layer. Alternatively, insulation layers can be installed on all four walls of both sides of the ditches to further enhance their insulation effect and reduce the impact of low temperatures in the external soil layer.

[0024] The drainage system includes circumferential blind pipes, longitudinal blind pipes, and transverse water guide pipes. The circumferential blind pipes are installed circumferentially along the tunnel arch wall, and the bottom of the circumferential blind pipes is connected to the longitudinal blind pipes. The transverse water guide pipes are connected to the longitudinal blind pipes and the insulation ditch, respectively, to guide and drain seepage water from the surrounding rock.

[0025] Multiple heating devices are provided, at least some of which are located at the top of the tunnel to heat the circumferential blind pipe, and at least some of which are located on one side of the insulated water ditch to heat the designated location of the insulated water ditch. The designated location is preferably at the upper limit of the permafrost at the top of the tunnel or in a shaded area at the tunnel entrance, where the drainage system collects seepage water from the surrounding rock of the tunnel and discharges the seepage water into the insulated water ditch.

[0026] Circumferential blind pipes are installed circumferentially along the tunnel arch wall, forming a circumferential drainage system. The bottom of these pipes connects to an insulated drainage ditch via longitudinal blind pipes and transverse guide pipes, guiding and draining seepage water from the surrounding rock. The insulated drainage ditch forms a longitudinal drainage system. Multiple circumferential blind pipes are distributed at designated locations within the tunnel, preferably at the upper limit of the permafrost at the tunnel roof or in a shaded area near the tunnel entrance. This system collects seepage water from the surrounding rock and discharges it into the insulated drainage ditch.

[0027] Multiple heating devices are installed. Some heating devices are located at the top of the tunnel to heat the circumferential blind pipes and correspond one-to-one with multiple circumferential blind pipes. The remaining heating devices are located on one side of the insulation ditch to heat the designated location of the insulation ditch. The designated location is preferably selected in the permafrost section of the tunnel and in the shaded area of ​​the tunnel entrance.

[0028] In other words, considering the difficulty and high cost of heating the entire drainage system, a point-to-point heating method can be used to heat the insulated water trench and the circumferential blind pipe. Active heating of the insulated water trench and the circumferential blind pipe improves the antifreeze effect. Compared to heating the entire drainage system, this method reduces implementation difficulty and cost, offering advantages such as low cost and ease of application.

[0029] This invention provides a fixed-point heating drainage system, in which the drainage system and multiple heating devices work together to centrally heat the drainage in the permafrost section, the upper limit of the permafrost layer, and the shaded area at the tunnel entrance, so as to ensure that the tunnel drainage system is unobstructed and not prone to freezing. At the same time, an insulation layer is laid on the four walls of the insulated water ditch to protect the temperature of the water flow in the ditch. Attached Figure Description

[0030] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0031] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of a cross-sectional view of a tunnel as described in an embodiment of this disclosure;

[0033] Figure 2 This is a schematic diagram of a longitudinal section sectional view of a tunnel according to an embodiment of this disclosure.

[0034] The components include: 1. Initial support; 2. Circumferential blind pipe; 3. Secondary lining; 4. Cable; 5. Connecting pipe; 6. Suction pump; 7. Longitudinal blind pipe; 8. Transverse water guide pipe; 9. Bracket; 10. Distribution box; 11. Suction heater; 12. Insulated water ditch; 13. Insulation layer; 14. Road surface; 15. Sedimentation well; 16. Seasonally frozen soil area; 17. Seasonally frozen soil section; 18. Permafrost section; 19. Upper limit of permafrost; 20. Sunny side of the tunnel entrance; 21. Shady side of the tunnel entrance. Detailed Implementation

[0035] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0036] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0037] Combination Figure 1 and Figure 2 As shown, the present invention provides a drainage system for permafrost tunnels based on suction heating, comprising:

[0038] Two insulated water ditches 12 are installed along the entire length of both sides of the tunnel, and each of the four walls of the insulated water ditches 12 is equipped with an insulation layer 13. These insulated water ditches 12 are buried underground, and the insulation layer 13 on the outer walls enhances the insulation effect of the ditches 12 on both sides, thereby reducing the impact of low temperatures in the external soil layer. Optionally, the insulation layer 13 is installed on all four walls of the ditches 12 on both sides, which further enhances the insulation effect of the ditches 12 on both sides and reduces the impact of low temperatures in the external soil layer.

[0039] The drainage system includes a circumferential blind pipe 2, a longitudinal blind pipe 7, and a transverse water guide pipe 8. The circumferential blind pipe 2 is arranged circumferentially along the tunnel arch wall. The bottom of the circumferential blind pipe 2 is connected to the longitudinal blind pipe 7. The transverse water guide pipe 8 is connected to the longitudinal blind pipe 7 and the insulation ditch 12 respectively, and is used to guide and drain seepage water from the surrounding rock.

[0040] Multiple heating devices are provided, at least some of which are located at the top of the tunnel to heat the circumferential blind pipe 2, and at least some of which are located on one side of the insulated water ditch 12 to heat the designated location of the insulated water ditch 12. The designated location is preferably selected at the upper limit of the permafrost at the top of the tunnel 19 or at the shaded area 21 of the tunnel entrance, i.e., the drainage system collects seepage water from the surrounding rock of the tunnel and discharges the seepage water into the insulated water ditch 12.

[0041] Circular blind pipes 2 are installed circumferentially along the tunnel arch wall to form a circumferential drainage system. Their bottoms are connected to the insulation ditch 12 via longitudinal blind pipes 7 and transverse water guide pipes 8, used to guide and discharge seepage water from the surrounding rock. The insulation ditch 12 forms a longitudinal drainage system. Multiple circumferential blind pipes 2 are distributed at designated locations within the tunnel, preferably at the upper limit of the permafrost at the tunnel top (19) or at a shaded area 21 near the tunnel entrance. This ensures the drainage system collects seepage water from the tunnel's surrounding rock and discharges it into the insulation ditch 12.

[0042] Multiple heating devices are provided. Some heating devices are located at the top of the tunnel to heat the circumferential blind pipes 2, and each corresponds to one of the multiple circumferential blind pipes 2. The remaining heating devices are located on one side of the insulated water ditch 12 to heat the set position of the insulated water ditch 12. The set position is preferably selected from the permafrost section 18 of the tunnel and the shaded area 21 of the tunnel entrance.

[0043] In other words, considering the difficulty and high cost of heating the entire drainage system, a point-to-point heating method can be used to heat the insulated water ditch 12 and the circumferential blind pipe 2. Active heating of the insulated water ditch 12 and the circumferential blind pipe 2 improves the antifreeze effect. Compared to heating the entire drainage system, this method reduces implementation difficulty and cost, offering advantages such as low cost and ease of application.

[0044] The heating should focus on areas that are easily affected by the low temperatures outside the tunnel, such as the two ends of the tunnel, the lower limit of the permafrost layer, and the shady areas at the tunnel entrance. The heating points in these areas should be arranged more densely.

[0045] In other words, the present invention provides a fixed-point heating and drainage system. The drainage system and multiple heating devices work together to provide fixed-point centralized heating for the drainage in the permafrost section 18, the upper limit of the permafrost layer, and the shaded area 21 at the tunnel entrance, so as to ensure that the tunnel drainage system is unobstructed and not prone to freezing. At the same time, an insulation layer 13 is laid on the four walls of the insulated water ditch 12 to protect the temperature of the water flow in the ditch.

[0046] Of course, in the seasonally frozen soil section 17 located at the sunny side of the tunnel entrance, where the cold weather outside the tunnel has a smaller impact, a small number of heating devices and drainage systems can also be installed at intervals along the tunnel axis.

[0047] There can be multiple drainage systems. Multiple drainage systems and multiple heating devices work together to provide centralized heating for drainage in permafrost sections, at the upper limit of the permafrost layer, and in the shaded areas of the tunnel entrance, so as to ensure that the tunnel drainage system is unobstructed and does not easily freeze. At the same time, insulation layers are laid on the four walls of the insulated water ditch to protect the temperature of the water flow in the ditch.

[0048] This embodiment can also actively heat areas prone to frost damage, such as both ends of the tunnel, the lower limit of the permafrost layer, and the shady area of ​​the tunnel entrance, which are also important for the circumferential drainage system.

[0049] In this embodiment, the heating point of the heating device can be set at the top of the tunnel, the suction heating machine 11 can be suspended by the steel frame 9, and the suction heating machine can be connected to the distribution box 10 by the cable 4 to ensure the normal operation of the suction heating machine 11.

[0050] In some embodiments, there are multiple circumferential blind pipes 2, which are spaced apart along the extension direction of the tunnel and distributed at designated locations within the tunnel. These designated locations are preferably located at the upper limit of the permafrost at the top of the tunnel (19) or at a shaded area 21 near the tunnel entrance, where the drainage system collects seepage water from the surrounding rock of the tunnel and discharges it into the insulated ditch 12.

[0051] In some embodiments, there are multiple transverse water pipes 8, which are spaced apart along the extension direction of the tunnel.

[0052] In some embodiments, the heating device includes a connecting pipe 5, a suction pump 6, and a suction heater 11 connected in sequence. One end of the connecting pipe 5 leads to the top of the circumferential blind pipe 2 or the bottom of the insulated water ditch 12. The suction heater 11 is used to heat the air or water pumped in by the suction pump 6. That is, the suction heater 11 heats the drainage and air in the circumferential blind pipe 2 and the insulated water ditch 12 through the suction pump 6. On the one hand, it heats the drainage system to prevent it from freezing, and on the other hand, it accelerates the water flow rate in the circumferential blind pipe 2 and the insulated water ditch 12, making the water less likely to freeze. To prevent the water from freezing, the suction heater 11 is provided. The suction heater 11 is connected to the insulated water ditch 12 or the circumferential blind pipe 2 through the connecting pipe 5. The suction pump 6 is used to make the water flow rapidly between the suction heater and the insulated water ditch 12 or the circumferential blind pipe 2, so that the heat can be quickly diffused to prevent the pipeline from freezing.

[0053] By employing a suction-type active heating method, the antifreeze effect is improved. This embodiment of the invention utilizes a fixed-point heating method based on suction heating, actively heating the insulated water ditch 12 and the circumferential blind pipe 2 to achieve a superior antifreeze effect. Compared to heating the entire drainage system, this method reduces implementation difficulty and construction costs, offering advantages such as low cost and ease of application. Both the suction heater 11 and the suction pump 6 are connected to the distribution box 10. Therefore, the permafrost tunnel drainage system based on suction heating also includes the distribution box 10, which is electrically connected to the suction heater 11 and the suction pump 6. The distribution box 10 is connected in series with the suction pump 6 and the suction heater 11 via a cable 4 to ensure the normal operation of the suction pump 6 and the suction heater 11.

[0054] Furthermore, the drainage system for permafrost tunnels based on suction heating also includes a sedimentation well 15, with a suction heater 11 placed above the sedimentation well 15, a pipe 5 inserted into the sedimentation well 15, and the sedimentation well inserted into the insulated water ditch 12.

[0055] The bottom of the insulated water ditch 12 is equipped with multiple sedimentation wells 15. One end of the pipe 5 is connected to the bottom of the sedimentation well 15. When the suction pump 6 pumps or drains water from the insulated water ditch 12, it will exert a certain pressure on the bottom of the insulated water ditch 12, which can easily cause perforation damage to the bottom of the insulated water ditch 12. Therefore, the setting of sedimentation wells 15 increases the stability of the insulated water ditch 12.

[0056] In other words, in order to understand the relevant status of the tunnel after it is in operation and to facilitate maintenance, this embodiment makes full use of the structure of the sedimentation well 15. By utilizing the hole of the sedimentation well, the suction heating machine 11 is placed above the sedimentation well 15, and the pipe 5 is inserted into the insulation water ditch 12 through the sedimentation well 15, thereby avoiding damage to the insulation water ditch 12 by opening the hole.

[0057] This embodiment makes full use of the structure of the sedimentation well 15, which facilitates the installation and maintenance of the suction heating machine 11, while reducing the damage to the opening of the insulation ditch 12. The suction heating machine 11 is concealed below the evacuation platform, without causing encroachment, with minimal disturbance to the permafrost, and is less likely to cause damage to the main tunnel.

[0058] Furthermore, multiple sedimentation wells 15 are evenly distributed along the tunnel axis, with a distance of 200m to 250m between adjacent sedimentation wells 15. Of course, in areas where the temperature inside the tunnel has been low for many years, the number of sedimentation wells 15 can be appropriately increased to cooperate with the heating device.

[0059] Preferably, the distance between two adjacent sedimentation wells 15 is 200m. The sedimentation wells 15 are equipped with heating devices to provide targeted and centralized heating for drainage in permafrost sections, the upper limit of the permafrost layer, and the shaded areas at the tunnel entrance, ensuring smooth drainage and preventing freezing. The suction heating machine 11 is placed above the sedimentation wells 15, and the connecting pipe 5 is inserted into the insulated water ditch 12 through the sedimentation wells 15, thus avoiding damage to the insulated water ditch 12 by making openings.

[0060] In some embodiments, the drainage system includes a circumferential blind pipe 2 and a transverse water guide pipe 8. The circumferential blind pipe 2 is arranged circumferentially between the initial support 1 and the secondary lining 3 of the tunnel. One end of the transverse water guide pipe 8 is connected to the insulation ditch 12. That is, the transverse water guide pipe 8 enters from the bottom side wall of the insulation ditch 12, and the other end passes through the tunnel wall and is connected to the bottom of the circumferential blind pipe 2.

[0061] It also includes a longitudinal blind pipe 7, which is installed along the entire length of both sides of the bottom of the tunnel. The longitudinal blind pipe 7 is connected to the joints of the transverse water guide pipe 8 and the circumferential blind pipe 2. In other words, the longitudinal blind pipe 7 connects and links the bottom of multiple circumferential blind pipes, which is used to collect seepage water from the surrounding rock and drainage from the circumferential blind pipes, and discharges the drainage into the insulation ditch 12 through the transverse water guide pipe.

[0062] In some embodiments, the insulation ditch 12 is buried within a range of 1m to 1.5m below the tunnel surface 14. When the burial depth is large, it is difficult to grasp its relevant status and carry out maintenance after the tunnel is in operation. Therefore, the burial depth should not be too deep, and the insulation ditch 12 is parallel to the tunnel surface 14.

[0063] In some embodiments, an evacuation platform is also included, which is provided along the entire length of both sides of the tunnel and is positioned above the heating device. This platform serves to allow passage for maintenance personnel and to conceal the heating device below. Concealing the suction-type heater 11 below the evacuation platform does not cause any encroachment.

[0064] In some embodiments, a bracket 9 is also included, which is fixedly connected to the top of the tunnel for supporting and fixing the heating device.

[0065] In summary, this disclosure has the following advantages:

[0066] This disclosure proposes a drainage system for a permafrost tunnel based on suction heating. Circumferential blind pipes 2 are arranged circumferentially along the tunnel arch wall to form a circumferential drainage system. The bottom of the system is connected to an insulated drainage ditch 12 via longitudinal blind pipes 7 and transverse water guide pipes 8 to guide and discharge seepage water from the surrounding rock. The insulated drainage ditch 12 forms a longitudinal drainage system. Multiple circumferential blind pipes 2 are distributed at designated locations within the tunnel, preferably at the upper limit of the permafrost at the tunnel top (19) or at a shaded area 21 near the tunnel entrance. The drainage system collects seepage water from the surrounding rock and discharges it into the insulated drainage ditch 12.

[0067] Multiple heating devices are provided. Some heating devices are located at the top of the tunnel to heat the circumferential blind pipes 2, and each corresponds to one of the multiple circumferential blind pipes 2. The remaining heating devices are located on one side of the insulated water ditch 12 to heat the set position of the insulated water ditch 12. The set position is preferably selected from the permafrost section 18 of the tunnel and the shaded area 21 of the tunnel entrance.

[0068] In other words, considering the difficulty and high cost of heating the entire drainage system, a point-to-point heating method can be used to heat the insulated water ditch 12 and the circumferential blind pipe 2. Active heating of the insulated water ditch 12 and the circumferential blind pipe 2 improves the antifreeze effect. Compared to heating the entire drainage system, this method reduces implementation difficulty and cost, offering advantages such as low cost and ease of application.

[0069] Multiple heating devices are provided, at least some of which are located at the top of the tunnel to heat the circumferential blind pipe 2, and at least some of which are located on one side of the insulated water ditch 12 to heat the designated location of the insulated water ditch 12. The designated location is preferably selected at the upper limit of the permafrost at the top of the tunnel 19 or at the shaded area 21 of the tunnel entrance, i.e., the drainage system collects seepage water from the surrounding rock of the tunnel and discharges the seepage water into the insulated water ditch 12.

[0070] By employing a targeted suction heating method, the heating measures for drainage systems in permafrost tunnels are enriched. Compared to a single insulated water ditch, this embodiment of the invention simultaneously utilizes suction-type active heating, resulting in superior antifreeze performance.

[0071] Existing drainage system heating methods typically heat the entire drainage system, which is difficult to implement and costly. This disclosure proposes a point-based heating method based on suction heating, simultaneously heating both the circumferential and longitudinal drainage systems, which is low-cost and easy to apply.

[0072] The existing drainage system heating measures have many supporting facilities, are prone to encroachment, cause great disturbance to permafrost, and are likely to damage the main tunnel.

[0073] This embodiment fully utilizes the sedimentation well structure, taking advantage of the well's openings to avoid drilling into the insulation ditch 12 and the circumferential blind pipe 2, thus preventing damage to the main tunnel. The suction heater 11 is placed above the sedimentation well 15, and the connecting pipe 5 is inserted into the insulation ditch 12 through the sedimentation well 15. This fully utilizes the structure of the sedimentation well 15, facilitating the installation and maintenance of the suction heater 11, while reducing damage to the insulation ditch 12 from drilling.

[0074] The suction-type heater 11 is concealed below the evacuation platform, which does not cause encroachment, has little disturbance to the permafrost, and is unlikely to damage the main tunnel.

[0075] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0076] The above are merely specific embodiments of this disclosure, enabling those skilled in the art to understand or implement this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A drainage system for permafrost tunnels based on suction heating, characterized in that, include: Two insulated water ditches (12) are provided along the entire length of both sides of the tunnel, and the four walls of the insulated water ditches (12) are provided with an insulation layer (13). The drainage system includes a circumferential blind pipe (2), a longitudinal blind pipe (7), and a transverse water guide pipe (8). The circumferential blind pipe (2) is arranged circumferentially along the tunnel arch wall. The bottom of the circumferential blind pipe (2) is connected to the longitudinal blind pipe (7). The transverse water guide pipe (8) is connected to the longitudinal blind pipe (7) and the heat-insulating water ditch (12) respectively, and is used to guide and discharge seepage water from the surrounding rock. Multiple heating devices, at least some of which are located at the top of the tunnel for heating the circumferential blind pipe (2), and at least some of which are located on one side of the insulated water ditch (12) for heating the designated position of the insulated water ditch (12); The heating device includes a pipe (5), a suction pump (6) and a suction heater (11) connected in sequence. One end of the pipe (5) is connected to the top of the circumferential blind pipe (2) or the bottom of the heat-insulating water ditch (12). The suction heater (11) is used to heat the air or water pumped in by the suction pump (6). Both the suction heater (11) and the suction pump (6) are connected to the distribution box (10).

2. The drainage system for permafrost tunnels based on suction heating according to claim 1, characterized in that, The number of the circumferential blind pipes (2) is multiple, and the multiple circumferential blind pipes (2) are spaced apart along the extension direction of the tunnel, and the multiple circumferential blind pipes (2) are distributed at a set position in the tunnel.

3. The drainage system for permafrost tunnels based on suction heating according to claim 1, characterized in that, The number of transverse water guide pipes (8) is multiple, and the multiple transverse water guide pipes (8) are spaced apart along the extension direction of the tunnel.

4. The drainage system for permafrost tunnels based on suction heating according to claim 1, characterized in that, It also includes a sedimentation well (15), the suction heater (11) is placed above the sedimentation well (15), the connecting pipe (5) is inserted into the sedimentation well (15), and the sedimentation well is inserted into the heat-insulating water ditch (12).

5. The drainage system for permafrost tunnels based on suction heating according to claim 4, characterized in that, Multiple sedimentation wells (15) are evenly distributed along the tunnel axis, and the distance between two adjacent sedimentation wells (15) is 200 m to 250 m.

6. The drainage system for permafrost tunnels based on suction heating according to claim 1, characterized in that, The circumferential blind pipe (2) is installed along the tunnel circumference between the initial support (1) and the secondary lining (3). One end of the transverse water pipe (8) is connected to the heat-insulating water ditch (12), and the other end passes through the tunnel invert and is connected to the bottom of the circumferential blind pipe (2). The longitudinal blind pipe (7) is installed along the entire length of both sides of the bottom of the tunnel, and the longitudinal blind pipe (7) is connected to the joint of the transverse water guide pipe (8) and the circumferential blind pipe (2).

7. The drainage system for permafrost tunnels based on suction heating according to claim 1, characterized in that, The heat-insulating ditch (12) is buried within 1 m to 1.5 m below the tunnel surface (14), and the heat-insulating ditch (12) is parallel to the tunnel surface (14).

8. The drainage system for permafrost tunnels based on suction heating according to claim 1, characterized in that, It also includes an evacuation platform, which is set along the entire length of both sides of the tunnel and is located above the heating device for maintenance personnel to pass through.

9. The drainage system for permafrost tunnels based on suction heating according to claim 1, characterized in that, It also includes a bracket (9) which is fixedly connected to the top of the tunnel to support and fix the heating device.

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