A ventilation and cooling device applicable to permafrost regions and a construction method thereof

Abstract

The present invention discloses a ventilation and cooling device and a construction method suitable for permafrost areas. The device comprises an outer tube and an inner tube which are nested and together form a first and a second channel which are connected at the lower end. A gravity flap valve is arranged below the inner tube, which can flip under the gravity of a heavy object and drive the heavy object to fall into the space below. The device of the present invention guides the circulation and convection of cold air by arranging a channel, thereby generating a cooling effect around the outer tube and cooling the frozen soil. By arranging the gravity flap valve, not only the length of the connecting port below the inner tube can be reduced, the air flow can be accelerated, and the heat dissipation and cooling efficiency can be improved, but also the accumulated ice or foreign matter in the channel can be quickly discharged to avoid channel blockage. In addition, the device occupies a small area, is easy to bury and install, and can be constructed after construction, so it is suitable for the reinforcement and repair of in-service roads. The construction method of the present invention can efficiently and safely complete the construction of the above-mentioned device, with little disturbance to the frozen soil, so it is suitable for high-altitude and cold areas.

Description

Technical Field

[0001] The invention relates to the technical field of frozen soil cooling, and in particular to a ventilation cooling device suitable for permafrost areas and a construction method. Background Art

[0002] Frozen soil is a special type of soil or rock containing ice. As a product of the combined effects of climate and geological factors, its engineering properties fluctuate with the external temperature, showing the characteristics of frost heave and thaw settlement. Affected by global warming and human engineering activities, the permafrost layer under the roadbed is prone to temperature rise and melting of the frozen layer. In the process of repeated freeze-thaw cycles, frost heave and thaw settlement occur alternately, resulting in frequent diseases of highway projects built on frozen soil foundations, seriously affecting the normal service level of the road, causing time waste and increased transportation costs.

[0003] The ventilated roadbed adopts the principle of convection heat transfer, which effectively improves the stability of the frozen soil foundation. It is an engineering measure that conforms to the survival and development of frozen soil. The survey results in recent years have shown that the application effect of this measure in frozen soil engineering is outstanding. Its regulation process is manifested as the blocking of heat flow in the roadbed under forced convection conditions, wall heat transfer and heat transfer by dissipation and evaporation, thereby reducing the foundation temperature and thus protecting the permafrost foundation. However, there are still some shortcomings in the use of ventilation pipes, which are specifically manifested as follows: First, the heat dissipation efficiency is low, and it is difficult to meet the needs of most projects by relying solely on natural convection of air to take away the heat in the pipe; second, the accumulation of ice and debris in the pipe is easy to block the pipe. When the temperature is too low, an ice ring will form on the channel wall, and the accumulation of ice rings will easily block the channel, resulting in air flow obstruction and device failure. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems existing in the prior art and provide a ventilation cooling device and a construction method suitable for permafrost areas, which can improve the heat dissipation efficiency and prevent ice from blocking the channel.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A ventilation and cooling device suitable for permafrost areas comprises an outer tube and an inner tube which are nested; the outer tube is buried in the frozen soil and its upper end extends to the atmosphere, the upper end of the inner tube extends out of the pipe mouth of the outer tube and is installed with an exhaust mechanism, a first channel is formed between the outer tube and the inner tube, a second channel is formed in the pipeline of the inner tube, and the first channel and the second channel are connected at the lower end of the inner tube; a gravity flap valve is provided in the outer tube, the gravity flap valve is located below the inner tube, the gravity flap valve can be flipped under the gravity of a heavy object, and drive the heavy object to fall into the space below the gravity flap valve.

[0007] The cooling device of the present invention forms a first channel for air to flow inward and a second channel for air to flow outward through the nested outer tube and inner tube. The first channel is adjacent to the frozen soil layer through the tube wall of the outer tube, so that the air in the first channel can absorb the heat in the frozen soil layer and take the heat out of the frozen soil layer through the second channel, thereby realizing rapid heat dissipation and cooling of the frozen soil, which is conducive to maintaining the stability of the frozen soil foundation.

[0008] At the same time, by installing an exhaust mechanism at the upper end of the inner tube, the air flow in the first channel and the second channel can be accelerated, thereby improving the heat dissipation efficiency of the device;

[0009] At the same time, by arranging a gravity flap valve under the inner tube, not only can the opening length of the connection between the first channel and the second channel be reduced, the air flow can be accelerated, thereby improving the heat dissipation and cooling efficiency; it can also quickly discharge foreign objects such as ice cubes or sand that have formed and fallen in the tube from the first channel and the second channel, avoiding accumulation and blockage of the channel;

[0010] At the same time, the cooling device occupies a small horizontal area, is easy to install and can be constructed after construction. It is not only suitable for unbuilt or under-construction projects, but also for the reinforcement and repair of existing roads. It has a wide range of applications and can significantly improve the strength and stability of the roadbed.

[0011] As a preferred embodiment of the present invention, the gravity flap valve includes a rotating rod and a valve plate, both ends of the rotating rod are fixed to the outer tube, the valve plate is rotatably mounted on the rotating rod, and the rotating rod is located on the central axis of the valve plate; this structural form is simple in structure and easy to install, and the rotating rod is located on the central axis of the valve plate, which can make the rotation of the valve plate smoother.

[0012] As a preferred embodiment of the present invention, a reset spring or a reset weight is provided on the gravity flap valve; when the ice cube slides off the gravity flap valve, it can assist the gravity flap valve to reset.

[0013] As a preferred embodiment of the present invention, a hollow seepage groove is provided below the gravity flap valve, so that cold water from melted ice can seep into the frozen soil.

[0014] As a preferred solution of the present invention, the exhaust mechanism includes a fan blade and a driving device, and the fan blade is installed at the upper end of the inner tube.

[0015] As a preferred embodiment of the present invention, the driving device is a spherical turbine and / or a motor; the spherical turbine is configured to utilize natural wind force to drive the fan blades to rotate, and the spherical turbine is unidirectionally rotating and will not change the air flow direction in the pipe; the motor can drive the fan blades to rotate when the natural wind force is insufficient.

[0016] As a preferred embodiment of the present invention, a temperature-controlled air damper is installed inside the inner pipe. By providing the temperature-controlled air damper, the cooling device can automatically close the second channel during high-temperature or warm periods, preventing heat from being introduced and exacerbating the thaw settlement of frozen soil.

[0017] As a preferred embodiment of the present invention, the outer pipe is a structural member made of a heat-conducting material. The heat-conducting material can accelerate the transfer of heat in the frozen soil into the first channel, which is beneficial to improving the cooling effect. The pipe wall of the outer pipe extending into the atmosphere is provided with a heat-insulating layer, which can reduce the transfer of external heat to the frozen soil through the pipe wall of the outer pipe.

[0018] As a preferred embodiment of the present invention, the outer pipe / the inner pipe is vertically or obliquely arranged in the frozen soil. Vertical arrangement is convenient for fabrication and installation. Oblique arrangement can increase the lateral support force, improve the anti-overturning ability, and also increase the cooling radius of the device, improving the cooling effect.

[0019] A construction method for a ventilation cooling device, including the above-mentioned ventilation cooling device applicable to permafrost regions, comprises the following steps:

[0020] S1. Positioning: Determine the installation points on both sides of the road subgrade. The installation points are arranged at intervals along the longitudinal direction of the road and are symmetrically distributed on both sides of the road.

[0021] S2. Drilling: Dry drill at the installation points to form drill holes.

[0022] S3. Hoisting: Lift the cooling device, bring the lower end of the outer pipe close to the orifice of the drill hole, and ensure that the outer pipe is parallel to the axial direction of the drill hole.

[0023] S4. Installation: Place the cooling device into the drill hole and support and fix it using a fixing device.

[0024] S5. Backfilling: Backfill the gap between the drill hole and the outer pipe with fine sand. After the fine sand freezes, remove the fixing device.

[0025] In the construction method of the present invention, the cooling devices are arranged at intervals along the longitudinal direction of the road and are symmetrically distributed on both sides of the road, which can achieve heat dissipation and heat conduction of the permafrost in the whole section of the road and prevent uneven settlement of the road subgrade.

[0026] At the same time, by using the method of dry drilling to form drill holes on both sides of the road subgrade, not only can the drilling quality be guaranteed, reducing the generation of cracks and deformities, but also the drilling requires less water source, which is suitable for construction in alpine and high-altitude permafrost regions.

[0027] At the same time, by using fine sand to backfill the gap and removing the fixing device after the fine sand freezes, the rapid fixation of the cooling device can be realized by utilizing the frost heave characteristics of the frozen soil. The construction is simple and convenient and causes little damage to the frozen soil.

[0028] Advantages of the present invention compared with the prior art:

[0029] 1. For the cooling device of the present invention, a first channel for air to flow inward and a second channel for air to flow outward are formed by nested outer and inner tubes. The first channel is adjacent to the frozen soil layer through the wall of the outer tube, so that the air in the first channel can absorb the heat in the frozen soil layer and take out the heat through the second channel, realizing rapid heat dissipation and heat conduction of the frozen soil, which is beneficial to maintaining the stability of the frozen soil foundation; by installing an exhaust mechanism at the upper end of the inner tube, the air flow in the first and second channels can be accelerated, improving the heat dissipation efficiency of the device; by setting a gravity flap valve below the inner tube, not only can the opening length at the connection of the first and second channels be reduced, accelerating the air flow and thus improving the heat dissipation and heat conduction efficiency, but also the ice cubes formed in the tube and foreign objects invaded by wind and sand can be quickly discharged from the first and second channels, avoiding blockage caused by accumulation; the horizontal floor area of this cooling device is small, easy to bury and install, and can be constructed after the project. It is applicable not only to unbuilt or under-construction projects, but also to the reinforcement and repair of in-service roads, with a wide range of applications and obvious improvement effects on the subgrade strength and stability.

[0030] 2. In a preferred solution, by setting a hollow seepage trough below the gravity flap valve, the cold water melted from the ice cubes can quickly seep into the frozen soil, promoting further cooling of the frozen soil.

[0031] 3. For the construction method of the present invention, the cooling devices are arranged at intervals along the longitudinal direction of the road and symmetrically distributed on both sides of the road, which can realize heat dissipation and heat conduction of the frozen soil in the whole section of the road and prevent uneven settlement of the road subgrade; by using the dry drilling method to drill holes on both sides of the road subgrade, not only can the drilling quality be guaranteed, reducing the generation of cracks and deformities, but also the drilling requires less water source and is suitable for construction in alpine and high-altitude permafrost areas; by backfilling the voids with fine sand and removing the fixing device after the fine sand freezes, the quick fixation of the cooling device can be realized by using the frost heaving characteristics of the frozen soil, with simple and convenient construction and little damage to the frozen soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural view of the cooling device of the present invention Figure 1 .

[0033] Figure 2 is Figure 1 detail drawing of part A in

[0034] Figure 3 is an installation schematic diagram of Embodiment 1 of the present invention.

[0035] Figure 4 is a schematic structural view of the cooling device of the present invention Figure 2。

[0036] Figure 5 Schematic diagram of the installation for Embodiment 2 of the present invention Figure 1 。

[0037] Figure 6 Schematic diagram of the installation for Embodiment 2 of the present invention Figure 2 。

[0038] Figure 7 Schematic layout diagram of the cooling device described in the present invention.

[0039] Figure 8 Cross-sectional form diagram of the outer tube and the inner tube described in the present invention.

[0040] Figure 9 Schematic structural diagram of the spherical blade described in the present invention.

[0041] Markings in the figure: 1 - outer tube, 2 - inner tube, 3 - first channel, 4 - second channel, 5 - spherical turbine, 6 - motor, 7 - temperature-controlled air damper, 8 - protective baffle, 9 - adjustable neck tube, 10 - gravity flap valve, 11 - hollow seepage groove. Detailed implementation manners

[0042] The present invention will be further described in detail below in conjunction with test examples and specific implementation manners. However, it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0043] Embodiment 1

[0044] As Figures 1-3 shown, a ventilation and cooling device applicable to permafrost regions includes an outer tube 1 and an inner tube 2 nested therein. Among them, the outer tube 1 is buried in the permafrost layer, and its upper end extends out of the permafrost layer and into the external atmosphere. The inner tube 2 is located inside the pipeline of the outer tube 1. A first channel 3 is formed between the pipe walls of the outer tube 1 and the inner tube 2, and a second channel 4 is formed inside the pipeline of the inner tube 2. The first channel 3 and the second channel 4 communicate at the lower end of the inner tube 2.

[0045] Those skilled in the art can understand that both the outer tube 1 and the inner tube 2 are tubular structural members, and the inner diameter of the outer tube 1 is larger than the outer diameter of the inner tube 2, so that the inner tube 2 can be nested inside the pipeline of the outer tube 1, and the first channel 3 and the second channel 4 are distinguished by the pipe walls of the two. The pipe body of the outer tube 1 is directly buried in the permafrost layer, so that the air in the first channel 3 can exchange heat with the permafrost layer through the pipe wall. This requires that the outer tube 1 has a certain burial length in the permafrost to enable the heat exchange to be carried out more fully.

[0046] It should be noted that the lower ends of the outer pipe 1 and the inner pipe 2 are located at or near the permafrost layer. Correspondingly, the upper ends extend out of or away from the permafrost layer.

[0047] The first channel 3 and the second channel 4 communicate through at the lower end of the inner pipe 2. That is, an opening can be provided at the lower end of the inner pipe 2, and this opening is placed inside the pipe of the outer pipe 1, so that the first channel 3 and the second channel 4 can perform air flow exchange through this opening.

[0048] Specifically, the outer pipe 1 and the inner pipe 2 can be round pipes, square pipes or other tubular structural members of other shapes.

[0049] Specifically, the inner pipe 2 can be located in the middle of the outer pipe 1 without sharing the pipe wall with the outer pipe 1, as shown in Figure 8 (a) in Figure 8 (b); or, the inner pipe 2 shares one or more pipe walls with the outer pipe 1, as shown in Figure 8 (c); it only needs to satisfy that a first channel 3 in contact with the permafrost layer and a second channel 4 that communicates with the first channel 3 at the lower end can be formed between the inner pipe 2 and the outer pipe 1.

[0050] Preferably, in this embodiment, the inner pipe 2 is located in the middle of the outer pipe 1 without sharing the pipe wall with the outer pipe 1, and an auxiliary support bracket is provided between the outer pipe 1 and the inner pipe 2 to maintain the position stability of the inner pipe 2. Such a structural form can increase the contact area between the permafrost layer and the first channel 3, promote heat transfer, and improve the cooling efficiency of the device.

[0051] The upper end of the inner pipe 2 extends out of the pipe orifice of the outer pipe 1 and is equipped with an exhaust mechanism. The exhaust mechanism can discharge the air in the inner pipe 2, that is, in the second channel 4, from the upper end opening of the inner pipe 2. The first channel 3 and the second channel 4 communicate through at the lower end of the inner pipe 2, so that the air in the first channel 3 flows into the second channel 4, and then a circulation process of air flowing from the outside atmosphere through the first channel 3, the second channel 4, and then flowing out from the upper end of the inner pipe 2 is realized; at the same time, in order to reduce the mutual influence between the two processes of air flowing into the first channel 3 and flowing out of the second channel 4, the pipe orifice of the inner pipe 2 can extend out of the outer pipe 1.

[0052] In addition, in order to prevent external rain, snow and foreign objects from entering the ventilation pipe through the outer pipe 1, a protective baffle 8 can be provided at the upper end of the outer pipe 1, and the protective baffle 8 can be fixed on the pipe wall of the inner pipe 2.

[0053] Those skilled in the art can understand that when the temperature difference between the inside and outside of the pipeline is too large and the cooling is too fast, it is easy to form an ice ring between the outer pipe 1 and the inner pipe 2. Under the action of gravity, the ice cubes will fall and accumulate at the bottom of the outer pipe 1. If the bottom surface of the outer pipe 1 is too close to the lower end opening of the inner pipe 2, it is very easy to be blocked by the accumulated ice cubes, resulting in the failure of the cooling device. If the bottom surface of the outer pipe 1 is too far from the lower end opening of the inner pipe 2, an air stagnation area will be formed below, affecting air flow and thus reducing the heat dissipation efficiency of the device. Therefore, a gravity flap valve 10 can be installed below the inner pipe 2.

[0054] The gravity flap valve 10 is a valve-type structural member that can be flipped according to the magnitude of the gravity / pressure of the heavy object applied to it. It usually includes a rotating shaft and a plate member that can rotate around the rotating shaft. When the gravity flap valve 10 is installed in the pipeline, the plate member can be used to block the pipeline and control the air flow direction therein. When ice cubes fall onto the gravity flap valve 10, the plate member can be flipped under the action of the gravity of the ice cubes and drive the ice cubes to slide off the gravity flap valve 10 and fall into the space below the gravity flap valve 10, so that the ice cubes will not accumulate in the first channel 3 and the second channel 4 and cause blockage.

[0055] Furthermore, the gravity flap valve 10 can be fixedly installed on the pipe wall of the outer pipe 1, and there is a certain distance between it and the lower end opening of the inner pipe 2. This distance can meet the rotation requirement of the gravity flap valve 10 and the air flow requirement between the first channel 3 and the second channel 4, and can accommodate a certain amount of ice cubes to avoid channel blockage when the gravity of the ice cubes is not enough to push the gravity flap valve 10 to rotate.

[0056] Furthermore, the space below the gravity flap valve 10 can be obtained by extending the outer pipe 1. An opening can be provided at the lower end of the outer pipe 1 so that after the ice cubes slide off the gravity flap valve 10, they can melt in the lower space and flow into the frozen soil layer.

[0057] Specifically, the gravity flap valve 10 can be composed of a rotating rod and a valve plate rotatably installed on the rotating rod. Among them, both ends of the rotating rod are fixed to the pipe wall of the outer pipe 1. When the valve plate is perpendicular to the axis of the outer pipe 1, it can better block the outer pipe 1 pipeline. When the ice cubes fall, the valve plate can rotate around the rotating rod so that the ice cubes can fall.

[0058] Specifically, for a square pipeline, the gravity flap valve 10 can be composed of two symmetric valve plates. One side of the valve plate is hinged to the inner wall of the pipeline. When the ice cubes fall, the valve plate can rotate towards the inner wall of the pipeline so that the ice cubes can fall.

[0059] Therefore, in the cooling device of the present invention, the first channel 3 for air to flow inward and the second channel 4 for air to flow outward are formed by the nested outer tube 1 and inner tube 2. The first channel 3 is adjacent to the frozen soil layer through the tube wall of the outer tube 1, so that the air in the first channel 3 can absorb the heat in the frozen soil layer and take the heat out of the frozen soil layer through the second channel 4, realizing the rapid heat dissipation and heat conduction of the frozen soil, which is beneficial to maintaining the stability of the frozen soil foundation; by installing an exhaust mechanism at the upper end of the inner tube 2, the air flow in the first channel 3 and the second channel 4 can be accelerated, improving the heat dissipation efficiency of the device; by arranging a gravity flap valve 10 below the inner tube 2, it can not only reduce the opening length at the connection of the first channel 3 and the second channel 4, accelerate the air flow, thereby improving the heat dissipation and heat conduction efficiency, but also quickly discharge the ice blocks formed in the tube and foreign objects invaded by sand and dust from the first channel 3 and the second channel 4, avoiding blockage caused by accumulation.

[0060] The cooling device of the present invention has a small horizontal floor area, is convenient to bury and install and can be constructed after the project. It is applicable not only to unbuilt or under-construction projects, but also to the reinforcement and repair of in-service roads, with a wide range of applications and obvious improvement effects on the subgrade strength and stability.

[0061] In a preferred solution, the gravity flap valve 10 is composed of a valve plate and a rotating rod. The two ends of the rotating rod are fixed to the tube wall of the outer tube 1 and are perpendicular to the axis of the outer tube 1. The valve plate is rotatably installed on the rotating rod. The shape of the valve plate can fit and is slightly smaller than the inner wall of the outer tube 1, so that the valve plate can not only better block the channel, but also rotate smoothly in the channel. At the same time, the rotating rod is located on the central axis of the valve plate, which can make the rotation of the valve plate easier; this structural form is simple to manufacture and convenient to install in the pipeline.

[0062] Furthermore, a reset device is also arranged on the gravity flap valve 10, which can restore the rotated valve plate to be perpendicular to the axis of the outer tube 1, enabling the gravity flap valve 10 to be reused.

[0063] Specifically, the reset device can be a reset spring, such as a torsion spring sleeved on the rotating rod or a tension spring with both ends respectively connected to the valve plate and the tube wall. When the ice block drives the valve plate to rotate, the torsion spring / tension spring compresses and stores energy. When the ice block slides off, the restoring force of the torsion spring / tension spring can reset the valve plate.

[0064] Specifically, the reset device can be a reset weight arranged below the valve plate. By reducing the center of gravity of the valve plate, the rotated valve plate can be automatically reset under the action of its own gravity.

[0065] In a preferred embodiment, a hollow seepage trough 11 is provided below the gravity flap valve 10. When the ice cubes slide down from the gravity flap valve 10, they will accumulate below and gradually melt into cold water. To quickly drain the cold water from the channel, a hollow seepage trough 11 can be provided below the gravity flap valve 10 to guide the cold water flow and quickly seep into the permafrost layer.

[0066] Specifically, the bottom end of the outer tube 1 can be set to an inverted conical shape, and hollow slots pointing to its vertex are opened on the side wall of the cone. Under the action of gravity, the cold water will flow along the side wall of the cone towards the vertex and quickly seep into the permafrost layer through the hollow slots, promoting further cooling of the permafrost layer.

[0067] In a preferred embodiment, the exhaust mechanism includes a wind blade and a driving device, and the wind blade is installed at the upper end opening of the inner tube 2. Those skilled in the art can understand that the rotation of the wind blade can drive the air flow from one side to the other side. By setting the upper end opening of the inner tube 2, the air in the inner tube 2 can be exhausted by driving the rotation of the wind blade, thereby driving the air to flow in the first channel 3 and the second channel 4.

[0068] Further, the driving device is a device for driving the rotation of the wind blade. The driving device can be a spherical turbine 5 and / or a motor 6. Among them, the spherical turbine 5 is a structural member that can rotate under the push of wind force, including spherical blades and a transmission shaft rod. The spherical blades are formed by overlapping multiple blades in a circular arrangement to form a spherical structure, and there are openings between adjacent two blades. Figure 9 When the air flows through the spherical blades, it can enter the opening from one side and push the spherical blades to rotate, and then drive the wind blade to rotate through the transmission shaft rod. Since the air can only enter the opening from one side, under the action of natural wind force, the spherical turbine 5 can only rotate in one direction and will not change the air flow direction in the pipe. At the same time, the spherical turbine 5 has high structural strength and is not easily damaged, and is suitable for alpine and high-altitude permafrost regions.

[0069] Further, the driving device can also be a motor 6. The motor 6 can be set separately and connected to the wind blade to drive the wind blade to rotate in one direction by electricity to achieve the exhaust of the air in the pipe. Or the motor 6 can be set on the transmission shaft rod of the spherical turbine 5. When the wind force is large, the spherical turbine 5 is driven by natural wind force to drive the wind blade to rotate. When the natural wind force is insufficient, the motor 6 can be started to drive the wind blade to rotate by electricity.

[0070] Particularly, an automatic control device can be set to control the opening and closing and gear adjustment of the motor 6 by detecting the temperature difference inside and outside the ventilation pipe or the magnitude of natural wind force, so that the motor 6 can be automatically turned on or the power can be increased when the temperature difference inside and outside is large and the temperature outside the pipe is lower than the temperature inside the pipe, and / or when the natural wind force is insufficient, thereby improving the heat dissipation efficiency of the cooling device. When the temperature difference inside and outside is small or the natural wind force is sufficient, the motor 6 can be automatically turned off, thereby saving power consumption.

[0071] Furthermore, the automatic control device and the motor 6 can be powered by a solar panel and an antifreeze gel battery.

[0072] In a preferred embodiment, a temperature-controlled air damper 7 is installed inside the inner pipe 2. Those skilled in the art can understand that the temperature-controlled air damper 7 is a valve-type device that can switch the opening and closing state or adjust the opening size according to the temperature condition. By setting the temperature-controlled air damper 7, the second channel 4 can be automatically closed during high-temperature or warm periods to avoid the circulation of external hot air in the ventilation pipe and exacerbate the thaw settlement of frozen soil.

[0073] Specifically, the temperature-controlled air damper 7 can use the solid-liquid phase change of the temperature-sensitive material to switch the opening and closing state of the air damper, or use a temperature sensor to monitor the atmospheric temperature and drive the motor to switch the opening and closing state of the air damper.

[0074] In a preferred embodiment, the outer pipe 1 is made of a heat-conducting material, such as heat-conducting metals and their alloys, ceramic materials, carbon fiber materials, etc. The heat-conducting material can accelerate the transfer of heat in the frozen soil into the first channel 3, thereby improving the heat dissipation and cooling effect of the device.

[0075] In a preferred embodiment, the pipe wall of the outer pipe 1 extending into the atmosphere is provided with a heat-insulating layer, which can prevent external heat from being transferred to the frozen soil through the pipe wall of the outer pipe 1 and cause thaw settlement of the frozen soil around the pipe wall.

[0076] Specifically, the heat-insulating layer material can be polyurethane, rock wool, inorganic fiber, glass wool, etc.

[0077] The working principle of this cooling device:

[0078] When the atmospheric temperature is low, the exhaust mechanism can prompt the cold air in the atmosphere to enter the first channel 3 from the upper opening of the outer pipe 1, absorb the heat in the frozen soil layer in the first channel 3, and then be discharged from the upper opening of the inner pipe 2 through the second channel 4, realizing the heat dissipation and cooling of the frozen soil layer.

[0079] When the temperature difference between the inside and outside is too large, an ice ring is likely to form in the first channel 3. When the temperature rises, the ice block falls onto the gravity flap valve 10. The gravity flap valve 10 flips under the gravity of the ice block and drives the ice block to fall into the lower space. In the lower space, the ice block continues to absorb heat and melts into cold water, which flows into the frozen soil layer through the hollow seepage groove 11.

[0080] Embodiment 2

[0081] As Figures 4-6 shown, the main difference between this embodiment and Embodiment 1 is that the outer pipe 1 and the inner pipe 2 of this embodiment are inclined in the frozen soil. The inclined setting can not only increase the lateral support force of the frozen soil layer on the outer pipe 1 and improve the anti-overturning ability of the cooling device, but also increase the cooling radius of the cooling device and improve the heat dissipation and cooling ability.

[0082] Specifically, the outer tube 1 and the inner tube 2 can be set as a linear structure and installed obliquely in the permafrost layer, such as Figure 6 ; alternatively, the outer tube 1 and the inner tube 2 can be set as a bent structure, with the lower bent section buried obliquely in the permafrost layer and the upper bent section set vertically outside the permafrost layer, such as Figure 5 .

[0083] Furthermore, in order to enable the spherical turbine 5 to obtain the best windward effect, an adjustable neck tube 9 can be provided at the upper part of the inner tube 2. The adjustable neck tube 9 is a connecting pipe fitting with adjustable bending length and angle. It is set below the wind blade and the spherical turbine 5. By adjusting the inclination angle of the adjustable neck tube 9, the spherical turbine 5 can obtain the best windward effect.

[0084] Specifically, the adjustable neck tube 9 can be a corrugated pipe, a bendable hose, etc.

[0085] Embodiment 3

[0086] This embodiment provides a construction method for a ventilation and cooling device, including a ventilation and cooling device applicable to permafrost regions as described in Embodiments 1 and 2, and comprising the following steps:

[0087] S1. Positioning: Determine the installation points on both sides of the road subgrade. The installation points are arranged at intervals along the longitudinal direction of the road and symmetrically distributed on both sides of the road;

[0088] S2. Drilling: Dry drill at the installation points to form drill holes;

[0089] S3. Hoisting: Use a crane to lift the cooling device, bring the lower end of the outer tube 1 close to the orifice of the drill hole, and ensure that the outer tube 1 is parallel to the axial direction of the drill hole;

[0090] S4. Installation: Place the cooling device into the drill hole and support and fix it using a fixing device;

[0091] S5. Backfilling: Backfill the gap between the drill hole and the outer tube 1 with fine sand, and remove the fixing device after the fine sand freezes.

[0092] Those skilled in the art can understand that for the road subgrade project in the permafrost region, the cooling devices should be arranged at intervals along the longitudinal direction of the road to achieve heat dissipation and heat conduction for the entire road section. At the same time, in order to prevent transverse uneven settlement of the road subgrade, the cooling devices can be symmetrically arranged on both sides of the road subgrade, such as Figure 7 ; in addition, if the installation of the cooling devices is too dense, the hot air discharged by one cooling device is easily absorbed by another cooling device, affecting the heat dissipation efficiency. Therefore, preferably, the distance between the installation points is greater than or equal to 10 meters.

[0093] After determining the installation points, a down-the-hole drill can be used to circularly drill holes at the installation points. The dry drilling method is adopted, which is beneficial to improving the drilling quality and reducing the impact on frozen soil. Of course, a small amount of cold water can be added according to the formation conditions. The depth of the drill hole can be 10 - 20 cm larger than the buried depth of the outer pipe 1 designed, and the buried depth of the outer pipe 1 in the active layer of frozen soil can be greater than or equal to 1 m to obtain a better heat dissipation effect.

[0094] After the drill holes are opened, a crane can be used to slowly lift the cooling device vertically and move it to the installation point, and the position of the outer pipe 1 can be adjusted so that the lower end of the outer pipe 1 is aligned with the orifice of the drill hole, and the axis of the outer pipe 1 is parallel to the axis of the drill hole. Then, the cooling device is slowly and naturally lowered, and forced installation is not allowed to avoid the outer pipe 1 colliding with the hole wall during the lowering process, causing the hole to collapse, or the frozen soil on the hole wall to fall off and reduce the depth of the drill hole.

[0095] After being lowered to the designed depth, a fixing device is used to support and fix the cooling device, and fine sand is used to fill the gap between the outer pipe 1 and the drill hole. No sundries such as wood chips and stones shall be mixed into the fine sand to avoid the occurrence of gaps or uneven backfilling. After the fine sand freezes, the fixing device can be removed, and the installation of the cooling device is completed.

[0096] In the construction method of the present invention, the cooling devices are arranged at intervals along the longitudinal direction of the road and symmetrically distributed on both sides of the road, which can realize the heat dissipation and heat conduction of frozen soil in the whole section of the road and prevent uneven settlement of the roadbed; the dry drilling method is adopted to drill holes on both sides of the roadbed, which can not only ensure the drilling quality, reduce the generation of cracks and deformities, but also requires less water source for the opening of the drill holes, and is suitable for the construction in alpine and high-altitude permafrost areas; the gap is backfilled with fine sand, and the fixing device is removed after the fine sand freezes, and the freeze-thaw characteristics of frozen soil can be used to quickly fix the cooling device, and the construction is simple and convenient and has little damage to frozen soil.

[0097] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A ventilation and cooling device applicable to permafrost regions, characterized in that, It includes an outer pipe (1) and an inner pipe (2) which are nested; The outer pipe (1) is buried in permafrost and its upper end extends to the atmosphere. The upper end of the inner pipe (2) extends out of the pipe orifice of the outer pipe (1) and is equipped with an exhaust mechanism. A first channel (3) is formed between the outer pipe (1) and the inner pipe (2), and a second channel (4) is formed inside the pipe of the inner pipe (2). The first channel (3) and the second channel (4) communicate at the lower end of the inner pipe (2); A gravity flap valve (10) is provided inside the outer pipe (1). The gravity flap valve (10) is located below the inner pipe (2). The gravity flap valve (10) can be flipped under the action of the gravity of a heavy object and drive the heavy object to fall into the space below the gravity flap valve (10); A hollow seepage tank (11) is arranged below the gravity flap valve (10); The exhaust mechanism includes a wind blade and a driving device. The wind blade is installed at the upper end of the inner pipe (2); A temperature-controlled air door (7) is installed inside the pipe of the inner pipe (2).

2. The ventilation and cooling device applicable to permafrost regions according to claim 1, characterized in that, The gravity flap valve (10) includes a rotating rod and a valve plate. The two ends of the rotating rod are fixed to the outer pipe. The valve plate is rotatably installed on the rotating rod, and the rotating rod is located on the central axis of the valve plate.

3. The ventilation and cooling device applicable to permafrost regions according to claim 2, characterized in that, A return spring or a return counterweight is provided on the gravity flap valve (10).

4. The ventilation and cooling device applicable to permafrost regions according to claim 1, characterized in that The driving device is a spherical turbine (5) and / or a motor (6).

5. The ventilation and cooling device applicable to permafrost regions according to claim 1, wherein The outer pipe (1) is a heat-conducting material structural member; the pipe wall of the outer pipe (1) extending to the atmosphere is provided with a heat-insulating layer.

6. A ventilation and cooling device applicable to permafrost regions according to any one of claims 1-5, characterized in that, The outer pipe (1) / the inner pipe (2) is vertically or obliquely arranged in permafrost.

7. A construction method of a ventilation and cooling device, characterized in that, A ventilation and cooling device applicable to permafrost regions as described in any one of claims 1-6, comprising the following steps: S1. Positioning: Determine installation points on both sides of the roadbed. The installation points are arranged at intervals along the longitudinal direction of the road and are symmetrically distributed on both sides of the road; S2. Drilling: Dry drill at the installation points to form drill holes; S3. Hoisting: Lift the cooling device, bring the lower end of the outer pipe (1) close to the orifice of the drill hole, and ensure that the outer pipe (1) is parallel to the axial direction of the drill hole; S4. Installation: Place the cooling device into the drill hole and support and fix it with a fixing device; S5. Backfilling: Backfill the gap between the drill hole and the outer pipe (1) with fine sand, and remove the fixing device after the fine sand freezes.

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