A high-temperature unstable permafrost pre-melting and vacuum preloading reinforcement system and a reinforcement method

Abstract

The application provides a high-temperature unstable permafrost pre-melting and vacuum preloading reinforcement system and a reinforcement method, and the system comprises a pre-melting and thawing device, a sealing system and a steam generator, and the sealing system and the steam generator are connected with the pre-melting and thawing device. The pre-melting and thawing device is matched with the steam generator, the high-temperature unstable permafrost is pre-melted by using steam convection and heat conduction, the pre-melting and thawing efficiency is improved, the system has the characteristics of green environmental protection, and has no adverse effect on subsequent engineering construction. The sealing system is matched with the pre-melting and thawing device to realize the drainage consolidation of the high-temperature unstable permafrost foundation, the thawing pipe and the soil body are prevented from being empty, the pre-melting and thawing efficiency is ensured, the uneven subsidence problem caused by repeated freezing and thawing cycles is eliminated, the bad properties of the frozen soil are changed, and the stability of the foundation is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of road engineering construction technology, and in particular relates to a high-temperature unstable permafrost pre-thaw and vacuum pre-compression reinforcement system and method. Background Technology

[0002] The total area of ​​permafrost in my country is 1.59 × 10⁻⁶. 6 km 2 The Qinghai-Tibet Plateau is the world's most extensive permafrost region in the mid-to-low latitudes. High-temperature unstable permafrost (referring to permafrost with an average annual ground temperature above -1.0℃) is mainly distributed in the shallow subsurface, with high water content and active ice-water phase transition, making it exceptionally sensitive to climate change. When engineering structures are built in high-temperature unstable permafrost regions, the heat exchange conditions between the earth and the atmosphere, as well as the water and heat transport processes, are altered. This causes heat to accumulate within the strata, leading to permafrost warming and degradation, severely threatening the stability of engineering structures. In recent years, with climate change and the continuous development of engineering projects in high-altitude and cold regions, the area and distribution of high-temperature unstable permafrost have been increasing year by year, making it increasingly difficult to guarantee the stability and durability of permafrost engineering projects.

[0003] With the implementation of projects such as the Qinghai-Tibet Highway and the Qinghai-Tibet Railway, and driven by the need for ecological protection on the plateau, a series of temperature control measures have been developed over the years under the guiding principle of "actively cooling the foundation" to protect permafrost. Special roadbed structures such as heat pipes, riprap, and ventilation pipes have been designed and constructed to effectively control or mitigate freeze-thaw deformation of permafrost. However, for high-temperature unstable permafrost, the effectiveness of these measures is very limited. Many pipelines and transportation projects built in high-temperature, ice-rich permafrost areas suffer from recurring freeze-thaw cracking, uneven deformation, and other problems that are difficult to eradicate. Taking the world's first high-altitude, high-cold permafrost highway—the Gongyu Expressway—as an example, relevant field monitoring results show that measures such as heat pipes, ventilation pipes, and riprap roadbeds cannot prevent ground temperature rise. Freeze-thaw subsidence of 5–15 cm is common in high-temperature unstable permafrost sections. Therefore, traditional temperature control measures are not suitable for high-temperature unstable permafrost. They not only fail to guarantee the stability and durability of the engineering structure, but also significantly increase maintenance costs due to frequent equipment inspections and repairs. Based on this, this patent proposes to use frozen soil pre-thaw reinforcement technology to transform high-temperature unstable frozen soil into consolidated and stable non-frozen soil, which can fundamentally overcome the phenomenon of soil re-freezing and thawing within the treatment depth range, significantly reduce uneven deformation caused by freeze-thaw, and thus effectively ensure the safe operation of engineering structures and facilities.

[0004] At present, experts and scholars at home and abroad have proposed methods for pre-thawing frozen soil, such as steam, electric heating and lime piles. However, the soil density recovery during the above pre-thawing process depends on the residual self-weight compaction and ignores the problem of drainage and reinforcement of the thawed soil. Especially in flat areas with poor drainage, the soil bearing capacity is not high after taking pre-thawing measures and the consolidation time is too long, which greatly limits the engineering application of this technology.

[0005] For example, Chinese utility model patent CN 215482867 U discloses a rapid thawing device for frozen soil that is easy to assemble. This thawing device uses the principle of raising the freezing point of frozen soil by injecting salt water into the soil and combining it with a drill bit for heating to thaw the frozen soil. However, its working efficiency is low because drilling and thawing can only be done one at a time. In addition, the increased water and salt content in the soil exacerbates freeze-thaw deformation and causes environmental pollution.

[0006] Chinese invention patent application publication number CN110172963A discloses a thawing method and device for treating island-shaped permafrost. This patent pre-thaws the permafrost by laying thawing pipes in the soil and using circulating high-concentration hot brine. However, the controllability of factors such as brine temperature and circulation rate is poor, and the drainage and consolidation of the thawed soil is not considered. Therefore, the mechanical and engineering properties of the thawed soil, such as strength, stiffness and bearing capacity, are difficult to guarantee.

[0007] Chinese invention patent application publication number CN106759244A discloses a device for improving the stability of frozen soil. First, an electric heating rod is used to thaw the soil, and then capillary tubes are buried around the heating rods to achieve water absorption and consolidation. However, this device uses capillary tubes wrapped with permeable cloth for drainage. The shrinkage of the soil volume during consolidation causes the capillary tubes to become detached, thus reducing drainage efficiency. Furthermore, the heating and drainage equipment lacks a comprehensive control and information feedback mechanism.

[0008] It can be seen that the above-mentioned patents generally suffer from problems such as low efficiency of frozen soil pre-thawing, poor controllability, and insufficient drainage and reinforcement, making it difficult to fundamentally solve the engineering problems caused by repeated freeze-thaw cycles of high-temperature unstable frozen soil. Summary of the Invention

[0009] The purpose of this invention is to provide a high-temperature unstable permafrost pre-thaw and vacuum pre-compression reinforcement system to solve the technical problems of low efficiency, poor controllability, and insufficient drainage reinforcement in existing devices or systems for handling permafrost pre-thaw.

[0010] To solve the above-mentioned technical problems, the specific technical solution of the present invention is as follows:

[0011] A pre-melting and vacuum pre-compression reinforcement system for high-temperature unstable permafrost, the system comprising a pre-melting device, a sealing system and a steam generator, wherein the sealing system and the steam generator are both connected to the pre-melting device;

[0012] The pre-melting and defrosting device includes a cylinder, a steam channel inside the cylinder, a steam inlet connected to the steam generator at the upper end of the cylinder, a plurality of steam nozzles on the side wall of the cylinder, the steam inlet and the steam nozzles being connected through the steam channel, and a clamping device at the lower end of the cylinder.

[0013] The sealing system includes a submersible pump housed in a pump box and an ejector connected to the submersible pump. A drain pipe is installed on the ejector, one end of which is connected to the ejector and the other end of which is clamped on a clamping device.

[0014] Therefore, by using a steam generator in conjunction with the pre-thawing device's cylinder, steam convection and heat conduction are utilized to pre-thaw high-temperature unstable permafrost. This improves pre-thawing efficiency while being environmentally friendly, with no adverse impact on subsequent engineering construction. The sealing system, in conjunction with the pre-thawing device, achieves drainage and consolidation of the high-temperature unstable permafrost foundation, preventing consolidation deformation that could cause the thawing pipe and soil to separate, ensuring pre-thawing efficiency, eliminating uneven settlement caused by repeated freeze-thaw cycles, altering the unfavorable properties of the permafrost, and effectively improving foundation stability.

[0015] Furthermore, the clamping device includes a connecting rod that passes through the cylinder, and a movable hinge is provided at the lower end of the connecting rod. A pipe tip movable flap and a clamp are installed on the movable hinge. The pipe tip movable flap is located on the outside of the clamp, and the drain pipe is clamped on the clamp.

[0016] Furthermore, a jet vacuum pump is installed at the bottom of the submersible pump.

[0017] Furthermore, the pre-melting and thawing device includes multiple cylinders embedded in the soil, and the drainage pipe includes a first drainage pipe installed on the jet injector, a second drainage pipe passing through the cylinder and clamped on the clamping device, and a drainage network horizontally arranged above the second drainage pipe, the drainage network connecting the first drainage pipe and the second drainage pipe.

[0018] Furthermore, the drainage pipe network is provided with several water suction holes.

[0019] Furthermore, a horizontal drainage system is provided above the pre-melting and thawing device. The horizontal drainage system includes a lower sand cushion layer and an upper sand cushion layer laid above the pre-melting and thawing device. A sealing membrane is provided on the upper sand cushion layer, and sealing trenches and soil mounds are provided on both sides of the lower sand cushion layer.

[0020] Furthermore, the sealing film is a polyvinyl chloride sealing film.

[0021] Based on the same inventive concept, this invention also provides a method for reinforcing high-temperature unstable permafrost using the pre-thawing and vacuum preloading reinforcement system described above, comprising the following steps:

[0022] Step 1: Turn on the steam generator to heat and thaw the soil using the pre-melting and thawing device;

[0023] Step 2: When the defrosting time reaches the expected value, turn off the steam generator and turn on the sealing system to drain water from the lower end of the cylinder through the drain pipe.

[0024] Step 3: After the pre-melted water has been drained, close the sealing system;

[0025] Step 4: Repeat steps 1 to 3 until the soil pre-melting is complete.

[0026] Therefore, this method integrates pre-melting and thawing with drainage and consolidation. The timely discharge of water effectively prevents the adverse thermal effects of pre-melting water seeping downwards. Furthermore, parameters such as temperature, pressure, and flow rate during the implementation process can be monitored and adjusted in real time.

[0027] The high-temperature unstable permafrost pre-thawing and vacuum preloading reinforcement system of the present invention has the following advantages:

[0028] (1) The pre-melting and vacuum drainage consolidation treatment method is adopted. The pre-melting and drainage consolidation of the high-temperature unstable permafrost foundation is achieved by using the pre-melting thawing pipe designed in conjunction with the vacuum sealing drainage system. This eliminates the problem of uneven settlement caused by repeated freeze-thaw cycles, changes the undesirable properties of the permafrost, and effectively improves the stability of the foundation.

[0029] (2) This invention pre-melts high-temperature unstable permafrost through steam convection and heat conduction, which improves the pre-melting efficiency and is environmentally friendly, with no adverse effects on subsequent engineering construction. This device integrates pre-melting, thawing and drainage consolidation. The timely discharge of water effectively prevents the adverse thermal effects of pre-melted water seeping downwards. Furthermore, parameters such as temperature, pressure and flow rate during the implementation process can be monitored in real time and adjusted promptly.

[0030] (3) The present invention uses a vacuum preloading method for drainage consolidation, which prevents the consolidation deformation from causing the thawing pipe and soil to separate, thus ensuring the pre-thawing efficiency.

[0031] (4) The sand cushion layer of the present invention has the functions of drainage and load-bearing, avoiding the problem of increased porosity and excessive looseness of the soil after dehydration, which facilitates the direct entry of subsequent projects for construction and greatly simplifies the treatment process. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the high-temperature unstable permafrost pre-melting and vacuum preloading reinforcement system of the present invention;

[0033] Figure 2 This is a schematic diagram of the steam generator structure of the present invention;

[0034] Figure 3 This is a schematic diagram of the pre-melting and defrosting device of the present invention;

[0035] Figure 4 This is a schematic diagram of the clamping device structure of the present invention;

[0036] Figure 5 This is a cross-sectional view of the cylinder of the present invention;

[0037] Figure 6 This is a schematic diagram of the sealing system structure of the present invention.

[0038] Explanation of markings in the diagram: 1. Pre-thawing device; 2. Lower sand cushion layer; 3. Upper sand cushion layer; 4. Drainage pipe network; 5. Lateral drainage system; 6. Sealing membrane; 7. Sealing trench; 8. Soil mound cofferdam; 9. Steam hose; 10. Drainage pipe; 101. First drainage pipe; 102. Second drainage pipe; 11. Jet vacuum pump; 12. Submersible pump; 13. Jet ejector; 14. Sealing system; 15. Pump box; 16. Steam generator; 17. Pressure relief valve; 18. Steam outlet; 19. Makeup water inlet; 20. Drain valve; 2 1. Electric heater; 22. Drain outlet; 23. Pressure gauge; 24. Pressure controller; 25. Steam outlet valve; 26. Main control; 27. Liquid level gauge; 28. Check valve; 29. ​​Solenoid valve; 30. Booster pump; 31. Steam tank body; 32. Steam inlet; 33. Cylinder; 331. Steam passage; 34. Steam nozzle; 35. Inner wall; 36. Reinforcing steel plate; 37. Permeable plate; 38. Connecting rod; 39. Connecting rod sleeve; 40. Movable hinge; 41. Pipe tip movable flap; 42. Clamp; 45. Clamping device. Detailed Implementation

[0039] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0040] like Figure 1 As shown, the high-temperature unstable permafrost pre-melting and vacuum pre-compression reinforcement system of this embodiment includes a pre-melting and thawing device 1, a sealing system 14, and a steam generator 16. The sealing system 14 and the steam generator 16 are both connected to the pre-melting and thawing device 1.

[0041] Specifically, such as Figure 2As shown, the steam generator 16 includes a steam tank body 31, a steam generator main control unit 26, a booster pump 30, a check valve 28, a level gauge 27, a solenoid valve 29, an electric heater 21, a pressure controller 24, and a pressure gauge 23. The steam tank body 31 is a sealed hollow steel cylinder structure. On the right side of the steam tank body 31, the water inlet 19 is sequentially connected to the booster pump 30, the solenoid valve 29, and the check valve 28. The booster pump 30 provides water to the device and regulates the inlet pressure and flow rate. The solenoid valve 29 controls and records the inlet flow rate, and the check valve 28 prevents water and steam backflow. An electric heater 21 is installed inside the cavity of the steam tank body 31, providing hot steam to the device. The top and sides of the steam tank are equipped with a pressure gauge 23, a pressure controller 24, and a level gauge 27 for monitoring and regulating the steam pressure and water level in the tank cavity. The steam generator is also equipped with a main control unit 26, which is used to set the internal temperature, pressure, and heating power of the tank. A drain valve 20 and a drain port 22 are connected to the bottom of the tank for easy cleaning of the tank cavity and removal of residual water. In one preferred embodiment, the steam generator is a small, integrated electrical device that can be flexibly powered in conjunction with construction vehicles. Preferably, a booster pump and a solenoid valve are installed at the steam generator's makeup water inlet to measure and control the flow rate of makeup water entering the evaporator. A pressure gauge and a pressure controller are installed at the top of the tank to achieve automatic control and real-time monitoring of the internal pressure.

[0042] Specifically, such as Figures 3 to 5 As shown, the pre-melting and defrosting device 1 includes a cylinder 33. The inner wall 35 and the reinforcing steel plate 36 of the cylinder 33 are both thickened steel structures. A steam channel 331 is provided inside the cylinder 33. A steam inlet 32 ​​connected to the steam generator 16 is provided at the upper end of the cylinder 33. A plurality of steam nozzles 34 are provided on the side wall of the cylinder 33. The steam inlet 32 ​​and the steam nozzles 34 are connected through the steam channel 331. A clamping device 45 is provided at the lower end of the cylinder 33.

[0043] Specifically, the sealing system 14 includes a submersible pump 12 housed within a pump housing 14, and an ejector 13 connected to the submersible pump 12. A jet vacuum pump 11 is installed at the bottom of the submersible pump 12, ensuring that the submersible pump 12 remains below the water surface in the pump housing 14, effectively preventing the submersible pump 12 from running dry. The ejector 13 is used to evacuate the sealing system 14 and adjust the system vacuum to control the drainage rate. The ejector 13 is connected to a vacuum gauge for easy limitation of the pumping flow rate. A drain pipe 10 is installed on the ejector 13, with one end connected to the ejector 13 and the other end clamped to the clamping device 45.

[0044] The cylinder 33 has a hollow structure. The clamping device 45 includes a connecting rod 38 that passes through the cylinder 33. The lower end of the connecting rod 38 is provided with a movable hinge 40. A pipe tip movable flap 41 and a clamp 42 are installed on the movable hinge 40. The pipe tip movable flap 41 is made of steel plate and is located on the outside of the clamp 42. The drain pipe 10 is clamped on the clamp 42. Specifically, at least three pipe tip movable flaps 41 are provided on the same clamping device 45. The opening and closing are controlled by lowering and raising the connecting rod 38. When the connecting rod 38 is lowered, the pipe tip movable flap 41 and the clamp 42 are driven to open together, inserting the drain pipe 10 clamped by the clamp 42 into the designated position at the bottom of the pre-melting and thawing pipe. When the pipe body is lowered, the reinforcing steel plate 36 will press against the inside of the pipe tip movable flap 41, transmitting pressure while restricting the movement of the movable flap, keeping it in a closed state, thus protecting the pre-melting and thawing pipe.

[0045] As a preferred embodiment of the present invention, such as Figure 1 and Figure 6 As shown, a horizontal drainage system 5 is provided above the pre-thawing device 1. The horizontal drainage system 5 includes a lower sand cushion layer 2 and an upper sand cushion layer 3 laid above the pre-thawing device 1. The lower sand cushion layer 2 and the upper sand cushion layer 3 can improve drainage conditions and shorten drainage distance. A sealing membrane 6 is provided on the upper sand cushion layer 3, and sealing trenches 7 and soil mounds 8 are provided on both sides of the lower sand cushion layer 2. Preferably, the sealing trenches 7 should be excavated below the shallow permeable layer, and the soil mounds 8 are used to fix the sealing membrane 6. The sealing membrane 6 is preferably a polyvinyl chloride (PVC) sealing membrane. The use of a PVC sealing membrane with strong anti-aging and puncture resistance achieves water- and air-tight sealing conditions, ensuring efficient drainage.

[0046] As another preferred embodiment of the present invention, such as Figure 1 and Figure 6 As shown, the pre-thawing device 1 includes multiple cylinders 33 embedded in the soil. The drainage pipe 10 includes a first drainage pipe 101 installed on the jet injector 13, a second drainage pipe 102 passing through the cylinders 33 and clamped on the clamping device 45, and a drainage network 4 horizontally positioned above the second drainage pipe 102. Specifically, the drainage network 4 is embedded in the upper sand cushion layer 3, and the drainage network 4 connects the first drainage pipe 101 and the second drainage pipe 102. Preferably, the drainage network 4 is made of rigid PVC material. The drainage network 4 has several water absorption holes to facilitate the collection of moisture from the sand cushion layer. A permeable filter cloth is laid outside the water absorption holes, which ensures the drainage performance of the water absorption holes while preventing soil particles from entering and causing blockage.

[0047] This embodiment also provides a construction and installation method for a high-temperature unstable permafrost pre-thaw and vacuum preloading reinforcement system, including the following key steps:

[0048] 1. After the site is leveled, drill holes at the designed locations of the thawing pipes according to the design requirements. The hole diameter should be 5-10cm larger than the pipe diameter.

[0049] 2. After assembling the pre-melting and defrosting device, the movable valve at the tip of the pipe, the second drainage pipe and the connecting rod, use a pile driving machine to statically press the pipe to the design depth. During the static pressing process, the pipe position should be checked in real time to ensure the verticality of the pipe body. One end of the second drainage pipe is fixed on the clamp inside the movable valve, and the other end is left with a sufficient length to extend out of the defrosting pipe for easy connection.

[0050] 3. After the pre-melting and defrosting tube is in static pressure, first push the connecting rod downward through the connecting rod sleeve to open the tube tip movable flap. At the same time, the second drain pipe is placed at the tube tip position as the clamp is released. Finally, close the tube top cover plate and use a steam hose to connect the steam outlet of the steam generator and the steam inlet of the defrosting tube.

[0051] 4. Lay the lower sand cushion layer and arrange the drainage pipe network. First, lay the longitudinal drainage pipe and connect the reserved end of the second drainage pipe to it. Then, use the first drainage pipe to connect the longitudinal drainage pipe to the jet vacuum pump. Finally, lay the upper sand cushion layer.

[0052] 5. Excavate the sealing trench and build an earthen embankment. Lay a polyvinyl chloride sealing membrane on the sand cushion layer, fill the sealing trench with water to seal it, and test its sealing performance.

[0053] Preferably, when the cylinder is lowered, the movable flap at the tip closes, which serves to expand the hole and reduce the pressure on the pipe body; the second drain pipe clamp and the movable flap at the tip are connected to the same movable hinge, and the clamp is released synchronously when the tip opens.

[0054] Preferably, the plastic core board of the second drainage pipe is wrapped with a layer of permeable filter cloth to ensure its drainage performance while preventing soil particles from entering and causing blockage. The drainage pipe network is a rigid perforated pipe, which facilitates the collection of water flowing within the sand cushion layer.

[0055] Preferably, the sand cushion layer is divided into upper and lower layers, which together form a horizontal drainage body. After the lower sand cushion layer is laid, it facilitates construction and protects the top of the thawing pipe.

[0056] It should be noted that the number and spacing of the cylinders in this invention should be adjusted according to the specific needs of the engineering construction. The pre-melting device, sealing system, and steam generator should be arranged simultaneously before the pre-melting work begins. In addition, to prevent excessive steam from affecting the vacuum seal, the pre-melting process and the vacuum drainage process should be carried out alternately. The steam generator should be turned off promptly after the frozen soil pre-melting is completed. The reinforcement process can only be ended after the relevant indicators of vacuum pre-compression consolidation meet the standards.

[0057] This embodiment also provides a method for reinforcement using the above-mentioned high-temperature unstable permafrost pre-thaw and vacuum preloading reinforcement system, including the following steps:

[0058] Step 1: Turn on the steam generator 16 to heat and thaw the soil using the pre-melting and thawing device 1.

[0059] Step 2: When the defrosting time reaches the expected value, turn off the steam generator 16 and turn on the sealing system 14 so that the drain pipe 10 drains water to the lower end of the cylinder 33.

[0060] Step 3: After the pre-melted water has been drained, close the sealing system 14.

[0061] Step 4: Repeat steps 1 to 3 until the soil pre-melting is complete.

[0062] Specifically, in step one: after setting the temperature, water level, pressure, and other parameters on the steam generator's main control panel, open the steam generator's water supply inlet and booster pump. Once the liquid level reaches the set value, start the electric heater to begin heating; simultaneously, fill the jet vacuum pump's water tank to the starting water level. After the water flow rate, pressure, and temperature in the steam generator reach the preset values ​​and stabilize, open the steam outlet valve to allow steam to enter the thawing pipe and heat and thaw the soil through the steam nozzle. In step four, pre-melting and drainage are carried out intermittently until the soil pre-melting is complete. Then, close the steam generator's water supply inlet valve and steam outlet valve, stop the booster pump and heater power supply, and turn on the jet vacuum pump until all water is drained, completing the soil thawing and consolidation.

[0063] Based on this, this embodiment focuses on the urgent needs of the transportation construction industry, addressing the shortcomings of current permafrost pre-thawing methods, technologies, and equipment, and aims to improve the construction and maintenance quality and service safety of road engineering in the Qinghai-Tibet Plateau permafrost region. This patent, based on the principles of steam pre-thawing and vacuum pre-compression drainage reinforcement, has developed a set of technologies and equipment suitable for the pre-thawing treatment and reinforcement of high-temperature unstable permafrost. The equipment includes core components such as a pre-thawing pipe, a steam generator, and a jet vacuum pump. Steam is injected through the pre-thawing pipe to thaw the soil, and in conjunction with the constructed vacuum drainage system, the steam pre-thawing and vacuum pump drainage are carried out intermittently. It is expected to simultaneously complete the pre-thawing and drainage consolidation of high-temperature unstable permafrost, achieving the effect of permafrost foundation improvement and reinforcement.

[0064] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A pre-thawing and vacuum preloading reinforcement system for high-temperature unstable permafrost, characterized in that, It includes a pre-melting and defrosting device (1), a sealing system (14), and a steam generator (16), both of which are connected to the pre-melting and defrosting device (1); The pre-melting and defrosting device (1) includes a cylinder (33), a steam channel (331) is provided inside the cylinder (33), a steam inlet (32) connected to the steam generator (16) is provided at the upper end of the cylinder (33), a plurality of steam nozzles (34) are provided on the side wall of the cylinder (33), the steam inlet (32) and the steam nozzles (34) are connected through the steam channel (331), and a clamping device (45) is provided at the lower end of the cylinder (33). The sealing system (14) includes a submersible pump (12) installed in a pump box and an ejector (13) connected to the submersible pump (12). A drain pipe (10) is installed on the ejector (13), one end of the drain pipe (10) is connected to the ejector (13), and the other end of the drain pipe (10) is clamped on the clamping device (45). The clamping device (45) includes a connecting rod (38) that passes through the cylinder (33). The lower end of the connecting rod (38) is provided with a movable hinge (40). A pipe tip movable flap (41) and a clamp (42) are installed on the movable hinge (40). The pipe tip movable flap (41) is located on the outside of the clamp (42). The drain pipe (10) is clamped on the clamp (42).

2. The high-temperature unstable permafrost pre-thawing and vacuum preloading reinforcement system according to claim 1, characterized in that, A jet vacuum pump (11) is installed at the bottom of the submersible pump (12).

3. The high-temperature unstable permafrost pre-thawing and vacuum preloading reinforcement system according to claim 1, characterized in that, The pre-melting and thawing device (1) includes multiple cylinders (33) embedded in the soil. The drainage pipe (10) includes a first drainage pipe (101) installed on the jet injector (13), a second drainage pipe (102) passing through the cylinder (33) and clamped on the clamping device (45), and a drainage network (4) horizontally arranged above the second drainage pipe (102). The drainage network (4) connects the first drainage pipe (101) and the second drainage pipe (102).

4. The high-temperature unstable permafrost pre-thawing and vacuum preloading reinforcement system according to claim 3, characterized in that, The drainage pipe network (4) is provided with several water suction holes.

5. The high-temperature unstable permafrost pre-thawing and vacuum preloading reinforcement system according to any one of claims 1 to 4, characterized in that, A horizontal drainage system (5) is provided above the pre-melting and thawing device (1). The horizontal drainage system (5) includes a lower sand cushion layer (2) and an upper sand cushion layer (3) laid above the pre-melting and thawing device (1). A sealing membrane (6) is provided on the upper sand cushion layer (3). Sealing ditches (7) and soil mounds and embankments (8) are provided on both sides of the lower sand cushion layer (2).

6. The high-temperature unstable permafrost pre-thawing and vacuum preloading reinforcement system according to claim 5, characterized in that, The sealing film (6) is a polyvinyl chloride sealing film.

7. A method for reinforcing high-temperature unstable permafrost using the pre-thawing and vacuum preloading reinforcement system according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Turn on the steam generator (16) to heat and thaw the soil using the pre-melting and thawing device (1); Step 2: When the defrosting time reaches the expected value, turn off the steam generator (16) and turn on the sealing system (14) so ​​that the drain pipe (10) drains water from the lower end of the cylinder (33); Step 3: After the pre-melted water has been drained, close the sealing system (14). Step 4: Repeat steps 1 to 3 until the soil pre-melting is complete.

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