CA3147316C

CA3147316C - Extrusion type frost heave preventing and heat gathering self-protective device and subgrade thereof

Info

Publication number: CA3147316C
Application number: CA3147316A
Authority: CA
Inventors: Qihao YU; Wenqiang ZHANG; Mingyang JIN
Original assignee: Northwest Institute of Eco Environment and Resources of CAS
Current assignee: Northwest Institute of Eco Environment and Resources of CAS
Priority date: 2021-03-25
Filing date: 2022-02-01
Publication date: 2024-06-11
Anticipated expiration: 2042-02-01
Also published as: CN113026463B; CA3147316A1; CN113026463A

Abstract

The invention provides an extrusion type frost heave preventing and heat gathering self-protective device and subgrade thereof, for preventing and treating engineering construction diseases in a seasonally frozen soil region. In the device, the solar heat absorber, the heat gathering tube and the circulating pump are connected from head to tail sequentially through the circulating tube to form a circulating loop where a circulating working medium is filled;
the circulating pump is configured to push the medium to flow in a direction from a lower collecting tube to an upper collecting tube, and squeezing plugs press the medium in the row tubes into the lower collecting tube under action of gravity. The device and subgrade can realize balanced and flat heating of the subgrade, thereby effectively avoiding generation of engineering diseases in the seasonally frozen soil region, and avoiding influence on stability and sealing performance of the device.

Description

EXTRUSION TYPE FROST HEAVE PREVENTING AND HEAT
GATHERING SELF-PROTECTIVE DEVICE AND SUBGRADE THEREOF
FIELD OF THE INVENTION
[0001] The present invention relates to the technical field of preventing and treating engineering construction diseases in a seasonally frozen soil region, and particularly to an extrusion type frost heave preventing and heat gathering self-protective device and subgrade thereof.
BACKGROUND OF THE INVENTION

[0002] An area of seasonally frozen soil region in China is about 5.137 million square kilometers, occupying 53.5% of the national territorial area. Seasonally frozen soil is affected by seasons, and is frozen in winters, and all melted in Summers. When seasonal frozen layer and seasonally thawed layer are melted in Summers, due to unevenness distribution of ice layers and ice lenses, an important reason why various buildings are deformed and destroyed is the formation of differential settlement of the soil layers. Characteristics of frost heave and thaw settlement of the seasonal frozen soil play a significant influence on engineering.
Therefore, engineering construction or projects in the seasonally frozen soil region shall be particularly noticed to consider the influence of the seasonal frozen soil on engineering and prevention measures thereof. As for the subgrade, forms of frost damage of the subgrade are mainly frost heave, thaw settlement, mud pumping, and the like.

[0003] The Xining to Golmud section of Qinghai-Tibet Railway is at the northeast part of Qinghai-Tibet Plateau, and railway lines go across coastal plains, alluvial plains,and ice platforms at the north of Qinghai Lake, where an average altitude is 3220 m. The mean annual precipitation is 376 mm, precipitation is unevenly distributed, most concentrated in July to September, the mean annual temperature is -0.6 C, and the average temperature in the coldest month January is -20.6 C.
At Xining to Golmud section of Qinghai-Tibet Railway, weather is cold, a freezing capacity of the temperature is strong, and a freezing depth is large, and the maximum freezing depth may reach 1.8 m, which belongs to a typical seasonally frozen soil region. Accordingly, engineering diseases such as frozen heave and thaw settlement of the subgrade caused by freezing and melting are relatively severe.

[0004] Recently, due to a continuous increase of precipitation at Qinghai-Tibet Plateau, causing enrichment of underground water and rising of water table, as well as the intensification of climate and environmental change, the engineering disease of freeze-thaw in such region is further increased, resulting in an important influence on long-term stability of the subgrade.
Although the previous study is made on diseases of the subgrade under action of engineering in Date Recue/Date Received 2023-07-04 seasonally frozen soil region, the study is mainly directed to issues such as action and influence of minor frozen heave engineering of the subgrade under working conditions of highway engineering or high-speed railway in regions such as northeast and northwest. However, study on growth features and distribution laws of engineering disease of freeze-thaw under special conditions such as a high water level, coarse filling, and strong freeze-thaw at Xining to Golmud section of Qinghai-Tibet Railway is still lacked. Application of methods such as replacement of foundation soil, building drainage facility for reducing water content of the subgrade bed, stabilizing soil heat preservation method with inorganic binder, artificial salinizing subgrade soil, chemical grouting, and waterproof curtain used in the common regions is difficult to satisfy requirements of actual engineering in such region, due to limitations of engineering conditions such as normal driving of trains without interruption of construction, and crack at processing positions and extreme difficulty in overall enclosure at a lower part of the subgrade caused by strong action of soil freezing and thawing. Since the previous study on engineering measures for treating such engineering diseases is weak, engineering issues affect stability and operating security of the subgrade for a long time.
SUMMARY OF THE INVENTION

[0005] An object of the invention includes providing an extrusion type frost heave preventing and heat gathering self-protective device and subgrade thereof, which can realize balanced and flat heating of the subgrade, thereby effectively avoiding generation of engineering diseases such as frost heave and uneven fluctuation of the subgrade in the seasonally frozen soil region, and also avoiding influence on stability and sealing performance of the device when the circulating working medium reaches a boiling point in Summers by controlling positions of the circulating working medium.

[0006] The embodiment of the invention can be implemented by:

[0007] In a first aspect, the invention provides an extrusion type frost heave preventing and heat gathering self-protective device, comprising a solar heat absorber, a circulating tube, a heat gathering tube and a circulating pump, the solar heat absorber, the heat gathering tube and the circulating pump being connected from head to tail sequentially through the circulating tube to form a circulating loop where a circulating working medium is filled, and the heat gathering tube is used to be inserted into a subgrade;

[0008] The solar heat absorber comprises a solar heat absorption panel, and an upper collecting tube, a lower collecting tube, row tubes and squeezing plugs mounted below the solar heat absorption panel, the upper collecting tube and the lower collecting tube are connected to both ends of the circulating tube, respectively, both ends of the row tubes are in communication with the upper collecting tube and the lower collecting tube, the squeezing plugs are movable inside the row tubes, the circulating pump is configured to push the circulating working medium to flow in Date Recue/Date Received 2023-07-04 a direction from the lower collecting tube to the upper collecting tube, and when the circulating pump stops working, the squeezing plugs press the circulating working medium in the row tubes into the lower collecting tube under action of gravity.

[0009] In such way, the heat absorbed by the solar heat absorber is transferred to the heat gathering tube via the circulating working medium, and heats soil around the heat gathering tube through heat release of the heat gathering tube inside the subgrade, such that the subgrade is always in a process of pure heat absorption and continuous accumulation of internal heat, thereby reaching heat gathering inside the subgrade and a state where the temperature is always held to be positive, and reaching objects of preventing and treating engineering diseases such as soil freezing of the subgrade and frost heave of the subgrade.

[0010] When the device works, the circulating working medium circulates in the circulating tube under driving of a pressure produced by rotation of the circulating pump.
As for the squeezing plugs in the row tubes, they move upwardly under action of a circulating pressure and a pushing force of the circulating working medium, circulating channels are opened, and the circulating working medium starts circulation.

[0011] When the device stops working, such as, in summers, the circulating working medium stops circulation. Firstly, under action of gravity, the circulating working medium flows back to inside of the heat gathering tube through the circulating tube, and a liquid level of the circulating working medium in the row tubes starts decreasing till a height of a liquid level of the device.
Secondly, the squeezing plugs further press the circulating working medium to the lower collecting tube under action of gravity, thereby further emptying the working medium in the row tubes, thereby avoiding a sharp rise of pressure of the whole device caused by boiling and vaporization of the circulating working medium under a high temperature condition of the solar heat absorber in the daytime of summers, and ensuring sealing performance, integrality and security of the whole device.

[0012] In an optional embodiment, the row tube comprises an upper half section connected to the upper collecting tube and a lower half section connected to the lower collecting tube, the squeezing plug is movable inside the upper half section and the lower half section, an inner diameter of the upper half section is greater than an inner diameter of the lower half section, and the inner diameter of the lower half section is greater than or equal to an outer diameter of the squeezing plug.

[0013] In such way, when the device works, the squeezing plug is pushed by the circulating working medium to move upward to the upper half section, such that the circulating working medium may pass through the row tubes, and when the device stops working, the squeezing plug falls into the lower half section under action of gravity, such that the circulating working medium can be discharged from the row tubes.

Date Recue/Date Received 2023-07-04

[0014] In an optional embodiment, a lower end of the squeezing plug is a spiked shape.

[0015] In an optional embodiment, a gravity of the squeezing plug is greater than a buoyancy when the squeezing plug is totally immerged into the circulating working medium.

[0016] In an optional embodiment, a height of a center of gravity of the solar heat absorber, a height of a center of gravity of the heat gathering tube and a height of a center of gravity of the circulating pump are lowered sequentially.

[0017] In an optional embodiment, when the circulating working medium and the squeezing plug are standing still, a liquid level of the circulating working medium does not exceed a top surface of the squeezing plug.

[0018] In an optional embodiment, the heat gathering tube comprises:

[0019] an outer tube;

[0020] a liquid inlet tube in communication with outside of the outer tube and one end of the circulating tube; and

[0021] a liquid outlet tube having one end inserted inside of the outer tube and provided with an opening in communication with the outer tube, and the other end extending out of the outer tube and in communication with the other end of the circulating tube.

[0022] In such way, a heat release flow channel of the circulating working medium between the outer tube and the liquid outlet tube is formed, and the circulating working medium dissipates heat in the heat release flow channel. The heat dissipation flow channel is long, and a heat transfer medium is only tube walls of the outer tube, so heat transfer efficiency is high.

[0023] In a second aspect, the invention provides an extrusion type frost heave preventing and heat gathering self-protective subgrade, the extrusion type frost heave preventing and heat gathering self-protective subgrade comprises a subgrade and the extrusion type frost heave preventing and heat gathering self-protective device according to any of the previous embodiments, wherein the solar heat absorber is mounted outside the subgrade, and the heat gathering tube is inserted inside the subgrade.

[0024] In an optional embodiment, the extrusion type frost heave preventing and heat gathering self-protective subgrade further comprises a heat preservation material layer disposed on a slope of the subgrade.

[0025] In such way, under condition of no solar radiation at night, the whole device stops working, and meanwhile the heat preservation material layer on an outer side of the subgrade effectively prevents large loss of heat inside the subgrade.
BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To clearly explain the technical solution in the embodiment of the invention, hereinafter the desired accompanying drawings in the embodiment are simply introduced. It shall Date Recue/Date Received 2023-07-04 be understood that hereinafter the drawings only illustrate some examples of the invention, so it shall not be viewed as definition to the scope. As for those ordinary in the art, on the premise of making no creative work, other relevant drawings also can be obtained based on these drawings.

[0027] FIG. 1 is a structural diagram of the extrusion type frost heave preventing and heat gathering self-protective subgrade provided in one embodiment of the invention.

[0028] FIG. 2 is a structural diagram of the extrusion type frost heave preventing and heat gathering self-protective device provided in one embodiment of the invention.

[0029] FIG. 3 is a structural diagram of the heat gathering tube in FIG. 2.

[0030] FIG. 4 is a state diagram when the extrusion type frost heave preventing and heat gathering self-protective device is working.

[0031] FIG. 5 is a side view of the solar heat absorber in FIG. 4.

[0032] FIG. 6 is a state diagram when the extrusion type frost heave preventing and heat gathering self-protective device stops working.

[0033] FIG. 7 is a side view of the solar heat absorber in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0034] To make objects, technical solutions and advantages of the embodiments of the invention clearer, hereinafter the technical solution in the embodiments of the invention is clearly and completely described with reference to the drawings in the embodiments of the invention.
Obviously, the described embodiments are a part of the embodiments of the invention, not all embodiments. Generally, components in the embodiments of the invention described and illustrated in the drawings can be arranged and designed in various different configurations.

[0035] Therefore, detailed descriptions of the embodiments of the invention provided in the drawings do not aim to limit the scope protected by the invention, but only represent the selected embodiments of the invention. Based on the embodiments in the invention, on the premise of making no creative work, all other embodiments obtained by those ordinary in the art belong to the scope protected by the invention.

[0036] It shall be noticed that similar reference signs and letters represent similar items in the drawings, so once one item is defined in one drawing, it is unnecessary to make further definition and explanation in subsequent drawings.

[0037] In the descriptions of the invention, it shall be noted that if orientation or positional relation indicated by terms "up", "down", "in" and "out" is orientation or positional relation illustrated based on the drawings, or common placed orientation or positional relation when the invention products are used, it is only to facilitate describing the invention and simplifying the descriptions, not indicating or suggesting that the device or element must have a specific Date Recue/Date Received 2023-07-04 orientation, and is constructed and operated in a specific orientation, so the invention is not limited thereto.

[0038] In addition, if there are terms "first" and "second", they are for distinguishing only, instead of indicating or suggesting relative importance.

[0039] It shall be noted that in the case of not conflicting, features in the embodiments of the invention can be combined with each other.

[0040] The embodiment of the invention is just proposed against the key scientific issue in frost heave of the subgrade, starting from "temperature of the subgrade" in three indispensable factors "water, soil and temperature" produced by frozen heave of the subgrade, thereby reaching objects of controlling the temperature and preventing frozen heave of the subgrade through the device provided in the embodiments of the invention.

[0041] Referring to FIG. 1, this embodiment provides an extrusion type frost heave preventing and heat gathering self-protective subgrade 1, comprising a subgrade 2, a heat preservation material layer 3 and extrusion type frost heave preventing and heat gathering self-protective devices 5, wherein the extrusion type frost heave preventing and heat gathering self-protective devices 5 are evenly mounted on one side of a sunny slope or one side of a shady slope of the subgrade 2 at an interval.

[0042] The heat preservation material layer 3 is disposed on a slope of the subgrade 2, can cover the entire slope of the subgrade 2, and is fixed by an anchor rod 4. In other embodiments, the heat preservation material layer 3 also can be compacted and fixed by covering a thin layer of soil or other material on an outer surface of the heat preservation material layer 3. The heat preservation material layer 3 can select building rock wool heat preservation material or an integrated heat preservation plate. Specifically, the sunny slope and the shady slope of the subgrade 2 can be provided with the heat preservation material layer 3, thereby preventing heat loss inside the subgrade 2, and effectively ensuring reservation of heat inside the subgrade 2 in the process of day-night change.

[0043] Referring to FIGS. 1 and 2, the extrusion type frost heave preventing and heat gathering self-protective device 5 comprises a solar heat absorber 6, a circulating tube 14, a heat gathering tube 15 and a circulating pump 19, wherein the solar heat absorber 6, the heat gathering tube 15 and the circulating pump 19 are connected from head to tail sequentially through the circulating tube 14 to form a circulating loop where a circulating working medium 20 is filled. The circulating working medium 20 is a non-freezing refrigerating liquid, glass water or other liquid under a condition of -30 C, and has good flowability. The circulating tube 14 is a metallic tube or a non-metallic tube resistant to wild solar radiation and aging.

[0044] The solar heat absorber 6 can be disposed in a natural surface region close to a foot of the sunny slope of the subgrade 2, and also can be disposed in a natural surface region of the shady Date Recue/Date Received 2023-07-04 slope of the subgrade 2 where sun can irradiate in winters, and the solar heat absorber 6 is configured to absorb solar energy and heats the circulating working medium 20.

[0045] The heat gathering tube 15 is used inserted the subgrade 2, and transfers heat of the circulating working medium to inside of the subgrade 2, such that the subgrade 2 is always in a process of pure heat absorption and continuous accumulation of internal heat, thereby reaching heat gathering inside the subgrade and a state where the temperature is always held to be positive, and reaching objects of preventing and treating engineering diseases such as soil freezing of the subgrade 2 and frost heave of the subgrade 2.

[0046] The heat gathering tube 15 is inserted the subgrade 2 within a range from a half to a foot of the slope of the subgrade 2, and an insertion direction is perpendicular to a length direction of the subgrade 2. A length of the heat gathering tube 15 can be determined according to actual conditions of sites. On the same slope of the subgrade 2, an interval between the two adjacent heat gathering tubes 15 can be 1 m to 5 m. An angle between the heat gathering tube 15 and a horizontal plane is within a range from -30 to 30 . In this embodiment, preferably, an angle of the heat gathering tube 15 upward lifting in a length direction from inside to outside of the subgrade 2 is 0 to 30 , in particular, 5 to 10 . In other words, as shown in FIG. 1, an angle of the heat gathering tube 15 between extension along a direction x and upward lifting along a direction y is 0 to 30 , such that a height of the heat gathering tube 15 is at a middle lower position of the subgrade 2, and the heat gathering tube 15 is across most regions of a width of the subgrade 2. In such way, it is convenient to mount the heat gathering tube 15 in the subgrade 2, a drilling depth is small and the number thereof is few, and the original engineering structure of the subgrade 2 is not changed, thereby ensuring stability of the original subgrade 2, having no influence on normal driving of trains during construction, and effectively solving difficulties in engineering construction when satisfying the condition of driving of the trains.

[0047] A height of a center of gravity of the solar heat absorber 6, a height of a center of gravity of the heat gathering tube 15 and a height of a center of gravity of the circulating pump 19 are lowered sequentially. In such way, when the device stops working, the circulating working medium 20 in the solar heat absorber 6 flows out of the solar heat absorber 6 as much as possible under action of gravity, and is stored in the heat gathering tube 15 or the circulating pump 19.

[0048] Referring to FIG. 3, the heat gathering tube 15 comprises an outer tube 16, a liquid inlet tube 17 in communication with outside of the outer tube 16 and one end of the circulating tube 14, and a liquid outlet tube 18 at a bottom of the outer tube 16, having one end inserted inside of the outer tube 16 and provided with an opening in communication with the outer tube 16, and the other end extending out of the outer tube 16 and in communication with the other end of the circulating tube 14. In such way, a heat release flow channel of the circulating working medium 20 is formed between the outer tube 16 and the liquid outlet tube 18, and the circulating working Date Recue/Date Received 2023-07-04 medium 20 dissipates heat in the heat release flow channel. The heat dissipation flow channel is long, and a heat transfer medium is only tube walls of the outer tube 16, so heat transfer efficiency is high. Design of the liquid inlet tube 17 and the liquid outlet tube 18 enables the circulating working medium 20 to fill the heat gathering tube 15, such that more sufficient heat exchange is performed between the circulating working medium 20 and the tube walls, thereby improving heating efficiency of the heat gathering tube 15 to the subgrade.

[0049] Referring to FIGS. 4 and 5, arrows in FIG. 4 represent a flowing direction of the circulating working medium 20, and the solar heat absorber 6 comprises a solar heat absorption panel 7, and an upper collecting tube 8, a lower collecting tube 9, row tubes 10 and squeezing plugs 13 mounted below the solar heat absorption panel 7.

[0050] The solar heat absorption panel 7 is mainly made of metallic or non-metallic heat absorption material, and has a thin thickness, and the specific thickness can be 1 mm to 3 mm.

[0051] A section of the row tubes 10 is a cylindrical metallic tube, and the row tubes 10 are a diameter-varied structure. The row tube 10 comprises an upper half section 11 connected to the upper collecting tube 8 and a lower half section 12 connected to the lower collecting tube 9, the squeezing plug 13 is movable inside the upper half section 11 and the lower half section 12, and an inner diameter of the upper half section 11 is greater than an inner diameter of the lower half section 12. Specifically, the inner diameter of the upper half section 11 can be 1 to 2 times of the inner diameter of the lower half section 12, and the inner diameter of the lower half section 12 is greater than or equal to an outer diameter of the squeezing plug 13.

[0052] A lower end of the squeezing plug 13 is a spiked shape. In such way, in the process of falling of the squeezing plug 13, the spiked shape can guide the squeezing plug 13 to insert the lower half section 12 of the row tubes 10. A gravity of the squeezing plug 13 is greater than a buoyancy when the squeezing plug 13 is totally immerged into the circulating working medium 20, such that when the device stops working, the squeezing plug13 can be ensured to go down freely, while extruding the circulating working medium 20 out of the row tubes 10.

[0053] Working principle of the extrusion type frost heave preventing and heat gathering self-protective device and subgrade thereof provided in this embodiment is as follows:

[0054] Referring to FIGS. 4 and 5, when the device works, the circulating working medium 20 circulates in the circulating tube 14 under driving of a pressure produced by rotation of the circulating pump 19. As for the squeezing plugs 13 in the row tubes 10, they move upward to the upper half section 11 of the row tubes 10 under action of a circulating pressure and a pushing force of the circulating working medium 20, circulating channels are opened, and the circulating working medium 20 starts circulation.

[0055] Referring to FIGS. 6 and 7, when the device stops working, such as, in Summers, the circulating working medium 20 stops circulation. Firstly, under action of gravity, the circulating Date Recue/Date Received 2023-07-04 working medium 20 flows back to inside of the heat gathering tube 15 through the circulating tube 14, and a liquid level of the circulating working medium 20 in the row tubes 10 starts decreasing till a height of a liquid level of the device. Secondly, the squeezing plugs 13 further press the circulating working medium 20 to the lower collecting tube 9 under action of gravity, thereby further emptying the working medium in the row tubes 10. Since the outer diameter of the squeezing plug 13 is substantially the same as the inner diameter of the lower half section 12 of the row tubes 10, the circulating working medium 20 in the lower half section 12 is substantially emptied. Moreover, when the circulating working medium 20 and the squeezing plug 13 are standing still, the liquid level of the circulating working medium 20 (shown by a dashed line in FIG. 6) does not exceed a top surface of the squeezing plug 13, thereby avoiding a sharp rise of pressure of the whole device caused by boiling and vaporization of the circulating working medium 20 under a high temperature condition of the solar heat absorber 6 in daytime of Summers, and ensuring sealing performance, integrality and security of the whole device.

[0056] Advantageous effects of the extrusion type frost heave preventing and heat gathering self-protective device and subgrade thereof provided in this embodiment comprise:

[0057] 1. Heat absorbed by the solar heat absorber 6 is transferred to the heat gathering tube 15 via the circulating working medium 20 to heat soil around the heat gathering tube 15 through continuous heat release of the heat gathering tube 15 inside the subgrade, such that the subgrade is always in a process of pure heat absorption and continuous accumulation of internal heat, thereby reaching heat gathering inside the subgrade and a state where the temperature is always held to be positive, and reaching objects of preventing and treating engineering diseases such as soil freezing of the subgrade and frost heave of the subgrade.

[0058] 2. The squeezing plugs 13 can empty the circulating working medium 20 from the row tubes 10 by designing the row tubes 10 to be dimeter-varied tubes, and disposing the squeezing plugs 13 in the row tubes 10, thereby avoiding issues of sealing performance and integrality of the device threatened by an increase of pressure of the device caused by boiling and vaporization of the circulating working medium 20, enhancing stability of the device in heating of the subgrade in the seasonally frozen soil region, and better preventing and controlling frost heave of the subgrade.

[0059] 3. The squeezing plugs 13 may select rubber to achieve the objects of the device. The device has characteristics of simple and useful and good stability, but can better solve technical and scientific difficulty of stability of the device.

[0060] The above disclosures are only detailed embodiments of the invention, but the protection scope of the invention is not limited thereto. Easily conceivable change or substitution for any skilled in the art within the technical range disclosed by the invention shall be covered within the protection scope of the invention. Therefore, the protection scope of the invention shall be subjected to the scope protected by the appended claims.

Date Recue/Date Received 2023-07-04

Claims

WHAT IS CLAIMED IS:

1. An extrusion type frost heave preventing and heat gathering self-protective device, characterized in that the extmsion type frost heave preventing and heat gathering self-protective device comprises a solar heat absorber, a circulating tube, a heat gathering tube and a circulating pump, the solar heat absorber, the heat gathering tube and the circulating pump being connected from head to tail sequentially through the circulating tube to form a circulating loop where a circulating working medium is filled, and the heat gathering tube is used to be inserted into a sub grade ;
the solar heat absorber comprises a solar heat absorption panel, and an upper collecting tube, a lower collecting tube, row tubes and squeezing plugs mounted below the solar heat absorption panel, the upper collecting tube and the lower collecting tube are connected to both ends of the circulating tube, respectively, both ends of the row tubes are in communication with the upper collecting tube and the lower collecting tube, the squeezing plugs are movable inside the row tubes, the circulating pump is configured to push the circulating working medium to flow in a direction from the lower collecting tube to the upper collecting tube, and when the circulating pump stops working, the squeezing plugs press the circulating working medium in the row tubes into the lower collecting tube under action of gravity.

2. The extrusion type frost heave preventing and heat gathering self-protective device according to claim 1, characterized in that the row tube comprises an upper half section connected to the upper collecting tube and a lower half section connected to the lower collecting tube, the squeezing plug is movable inside the upper half section and the lower half section, an inner diameter of the upper half section is greater than an inner diameter of the lower half section, and the inner diameter of the lower half section is greater than or equal to an outer diameter of the squeezing plug.

3. The extrusion type frost heave preventing and heat gathering self-protective device according to claim 1, characterized in that a lower end of the squeezing plug is a spiked shape.
Date Recue/Date Received 2023-07-04

4. The extrusion type frost heave preventing and heat gathering self-protective device according to claim 1, characterized in that a gravity of the squeezing plugs is greater than a buoyancy when the squeezing plugs is totally immerged into the circulating working medium.

5. The extrusion type frost heave preventing and heat gathering self-protective device according to claim 1, characterized in that a height of a center of gravity of the solar heat absorber, a height of a center of gravity of the heat gathering tube and a height of a center of gravity of the circulating pump are lowered sequentially.

6. The extrusion type frost heave preventing and heat gathering self-protective device according to claim 5, characterized in that when the circulating working medium and the squeezing plug are standing still, a liquid level of the circulating working medium does not exceed a top surface of the squeezing plug.

7. The extrusion type frost heave preventing and heat gathering self-protective device according to claim 1, characterized in that the heat gathering tube comprises:
an outer tube;
a liquid inlet tube in communication with outside of the outer tube and one end of the circulating tube; and a liquid outlet tube having one end inserted inside of the outer tube and provided with an opening in communication with the outer tube, and the other end extending out of the outer tube and in communication with the other end of the circulating tube.

8. An extrusion type frost heave preventing and heat gathering self-protective subgrade, characterized in that the extrusion type frost heave preventing and heat gathering self-protective subgrade comprises a subgrade and the extrusion type frost heave preventing and heat gathering self-protective device according to any one of claims 1 to 7, wherein the solar heat absorber is mounted outside the subgrade, and the heat gathering tube is inserted inside the subgrade.

9. The extrusion type frost heave preventing and heat gathering self-protective subgrade according to claim 8, characterized in that the extrusion type frost heave preventing and heat Date Recue/Date Received 2023-07-04 gathering self-protective subgrade further comprises a heat preservation material layer disposed on a slope of the subgrade.

Date Recue/Date Received 2023-07-04