A shallow buried self-anchored pile foundation freeze-up prevention and control device and construction method in frozen soil areas

Abstract

The present invention discloses a shallow-buried self-anchored pile foundation freeze-up prevention and control device in a frozen soil area and a construction method, comprising an anchoring tube, a sleeve, a pile foundation and a base, wherein the pile foundation and the base are installed in the anchoring tube, the pile foundation is installed on the top of the base, and the sleeve is sleeved on the anchoring tube; the upper block, the lower block, the upper slot and the lower slot of the anchoring tube of the present invention provide the anchoring tube with a function of changing the cross-section in real time according to the development of frost heave. At the same time, the synergistic effect of the block and the support optimizes the stress conditions of the pile foundation during the frost heave period. When the upper block tilts inward and deforms during the frost heave period, the squeeze support shrinks toward the pile foundation, and the gap between the block and the support gradually decreases until the two are in contact. The block presses down the support, and the support applies a downward force to the pile foundation to prevent the pile foundation from pulling up. Moreover, the base strengthens the stability and freeze-up resistance of the pile foundation, enabling the shallow-buried pile foundation to meet stringent deformation control requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of construction for preventing and controlling frost uplift of light and shallow pile foundations, and in particular to a device for preventing and controlling frost uplift of shallow-buried self-anchored pile foundations in permafrost areas and a construction method thereof. Background Art

[0002] The unique climatic and geological conditions in permafrost areas pose severe challenges to pile foundation engineering. During the seasonal transition, the frost heave effect caused by repeated freezing and thawing of the soil can seriously affect the stability of the pile foundation, causing deformation of the superstructure at the least and engineering accidents at the worst. To address this problem, the engineering community generally adopts the method of increasing the buried depth of the pile foundation to resist the frost heave force by leveraging the anchoring effect of the deep soil. Although this traditional method is theoretically reliable, it has obvious limitations in practical application: for projects with lighter loads and shallower buried depths, excessive buried depth requirements not only greatly increase material consumption, but also significantly increase construction difficulty and project costs, making it difficult to meet engineering needs in terms of economy and practicality.

[0003] The frost heave prevention and control technologies currently used in engineering practice mainly include physical isolation, soil improvement, drainage and anti-seepage, and structural reinforcement. Although these methods can work under certain conditions, they each have obvious shortcomings: some have complex construction processes and demanding working conditions; some have unstable prevention and control effects and are difficult to adapt to complex frozen soil environments; and some projects are too expensive and not worth promoting on a large scale. Especially in light and shallow pile foundation projects with strict requirements for deformation control, the applicability of existing technologies is even more insufficient. Therefore, the development of a new type of pile foundation structure that can effectively prevent and control frost heave deformation and has the advantages of simple construction and economic rationality has become a key technical problem that needs to be solved urgently in the current construction of frozen soil areas.

[0004] In view of this, the present invention proposes a shallow buried self-anchored pile foundation frost uplift prevention and control device and construction method in permafrost areas, which utilizes the horizontal frost heave force and the radial compression deformation of the structure itself to form a self-anchored anti-freeze uplift structure, providing an innovative solution for the prevention and control of shallow pile foundation diseases. Summary of the Invention

[0005] The purpose of the present invention is to address the technical defects existing in the prior art and to provide a shallow buried self-anchored pile foundation frost uplift prevention and control device in permafrost areas. The device utilizes the extrusion of shallow horizontal frost heave force to achieve the function of vertical variable cross-section, thereby forming a wedge-shaped self-anchoring mechanism, effectively alleviating the problem of frost uplift disease of shallow buried pile foundations.

[0006] Another object of the present invention is to provide a construction method for the above-mentioned shallow buried self-anchored pile foundation freeze-up prevention and control device in permafrost areas.

[0007] The technical solution adopted to achieve the purpose of the present invention is:

[0008] A shallow-buried self-anchored pile foundation freeze-up prevention and control device for frozen soil areas, comprising an anchoring tube, a sleeve, a pile foundation, and a base. The pile foundation and the base are installed in the anchoring tube, the pile foundation is installed on the top of the base, and the sleeve is sleeved on the anchoring tube.

[0009] The anchor cylinder includes a plurality of upper blocks located in the active layer of the frozen soil zone, a plurality of lower blocks located in the frozen soil layer of the frozen soil zone, a card block, and a connecting ring arranged between the upper blocks and the lower blocks; the upper blocks and the lower blocks are arranged correspondingly up and down, and the plurality of upper blocks are enclosed to form a cylindrical structure with a plurality of upper grooves, each of the upper grooves is arranged between two adjacent upper blocks, and a plurality of card blocks are arranged at different heights on the inner wall of each upper block, and the plurality of lower blocks are enclosed to form a cylindrical structure with a plurality of lower grooves, each of the lower grooves is arranged between two adjacent lower blocks, and a first card block is fixed to the outer edge of the bottom of each lower block;

[0010] A plurality of supports are evenly spaced along the axial direction of the pile foundation, one end of each support is fixed on the pile foundation, each support extends obliquely upward, and the other end is located below a clamping block, and there is a gap between the clamping block and the base, and a plurality of limiting protrusions are evenly fixed along the circumference of the base, each limiting protrusion corresponds to a lower slot and fits with the lower slot, and a second clamping block is fixed on the outer edge of the bottom of each limiting protrusion, and the second clamping block and the first clamping block are alternately spaced to form a clamping ring protruding outward.

[0011] In the above technical solution, a lower slot is correspondingly provided below each upper slot, and the upper block and the lower block are elastic structures.

[0012] In the above technical solution, the upper slot opens upward, and its bottom slot wall is the upper top surface of the connecting ring; the lower slot opens downward, and its bottom slot wall is the lower bottom surface of the connecting ring.

[0013] In the above technical solution, the thickness of the limiting protrusion is the same as the thickness of the lower block, so that the limiting protrusion fits in the lower groove, and the limiting protrusion and the lower block are alternately arranged to form a cylindrical shape. The upper top surface of the limiting protrusion contacts the lower bottom surface of the connecting ring, and the upper top surface of the base is flush with the upper top surface of the connecting ring.

[0014] In the above technical solution, the sleeve is a steel wire reinforced rubber sleeve, and the outer wall of the sleeve is coated with Teflon coating.

[0015] In the above technical solution, the length of the upper block is greater than the length of the lower block.

[0016] Another aspect of the present invention also includes a method for operating the frozen soil region shallow buried self-anchored pile foundation freeze-up prevention and control device, comprising the following steps:

[0017] Step 1: When the shallow layer of the permafrost zone freezes, it triggers frost heave in the surrounding soil, generating tangential and horizontal frost heave forces on the self-anchored pile foundation freeze-up prevention and control device. Under the action of the horizontal frost heave force, the sleeve undergoes elastic deformation until the upper block is squeezed inward and the lower block is driven outward, forming a "seesaw" effect with the connecting ring as the fulcrum. At the same time, the first blocking block is squeezed and inserted into the surrounding soil.

[0018] In step 2, frost heave continues to develop, the upper block further tilts and deforms inward, the support shrinks toward the pile foundation, the blocking block moves downward with the tilt of the upper block, the gap between the blocking block and the support gradually decreases until the two are in contact, the blocking block squeezes the support downward, the pile foundation bears downward pressure, and the pile foundation is prevented from pulling up.

[0019] In the above technical solution, when frost heave of the surrounding soil develops, the limiting protrusion is inserted into the frozen soil layer to limit the anchor tube.

[0020] In the above technical solution, the second blocking block engages with the surrounding soil, and the base serves as the base structure of the pile foundation to prevent the pile foundation from being pulled up.

[0021] In the above technical solution, the lower bottom surface of the sleeve is flush with the lower bottom surface of the connecting ring, and the lower part of the sleeve is located in the frozen soil layer in the frozen soil area.

[0022] Another aspect of the present invention also includes a construction method of a shallow-buried self-anchored pile foundation freeze-up prevention and control device in a frozen soil region, comprising the following steps:

[0023] Step 1, construction preparation: On-site survey to determine the depth of the active layer and geological conditions in the permafrost area, mark the pile positions and clean the site;

[0024] Step 2, Pile foundation positioning: Locate the center coordinates of the pile foundation, mark the excavation range and depth, and check the length of the anchor sleeve according to the frozen soil depth to ensure that the lower end of the sleeve is embedded at least 0.5m below the frozen soil layer in the frozen soil area;

[0025] Step 3, Drilling: Drill vertically to the marked range and depth. The diameter of the hole should be 10-15 cm larger than the outer diameter of the anchor tube. After drilling, clean the residue at the bottom of the hole and check the integrity of the hole wall to prevent the hole from collapsing and affecting the installation.

[0026] Step 4: hoist the structure of the self-anchored pile foundation freeze-up prevention and control device except the sleeve until the retaining ring is in close contact with the bottom of the drill hole, and then hoist the sleeve until the bottom surface is flush with the bottom surface of the connecting ring;

[0027] Step 5, backfill and compaction: Backfill weak frost-heaving gravel in layers outside the inner casing of the borehole to the top of the casing, with each layer ≤30cm thick. Use a plate compactor to compact the backfill. Replace the original soil within 0.5m from the top of the casing and compact it to ensure that the backfill and the surrounding frozen soil deform in coordination.

[0028] Step 6, completion acceptance: Check the sealing of the sleeve, the movable gap between the support and the block, and the fit between the limit protrusion and the lower slot, conduct a static load test to verify the bearing capacity of the entire structure, measure the verticality deviation of the pile foundation, and retain construction records and video data for archiving.

[0029] In the above technical solution, a total station or GPS is used to locate the center coordinates of the pile foundation.

[0030] In the above technical solution, a spiral drilling machine is used for vertical drilling.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The arrangement of the upper block, lower block, upper slot and lower slot of the anchor tube of the present invention provides the anchor tube with the function of changing cross-section in real time according to the development of frost heave. At the same time, the synergistic effect of the block and the support optimizes the stress conditions of the pile foundation during the frost heave period. When the upper block tilts inward and deforms during the frost heave period, the squeeze support shrinks toward the pile foundation, and the gap between the block and the support gradually decreases until the two are in contact. The block presses down the support, and the support applies a downward force to the pile foundation to prevent the pile foundation from pulling up. Moreover, the base strengthens the stability and anti-freeze pullout capability of the pile foundation, enabling the shallow buried pile foundation to meet stringent deformation control requirements;

[0033] 2. Backfilling weak frost-heaving gravel between the device of the present invention and the hole wall further alleviates the frost-heaving deformation of the pile foundation. First, the backfill soil has weak frost-heaving characteristics, and its own frost heaving can be ignored. It only deforms and displaces under the influence of the frost heaving of the soil outside the hole wall, forming a deformation buffer layer between the natural soil and the structure, reducing the intensity of the frost heaving development of the soil around the pile; on the other hand, the backfill soil is gravel, which is a coarse-grained filler with a relatively large particle size, which significantly reduces the contact and friction between the soil and the side wall of the structure. Therefore, backfilling weak frost-heaving gravel can directly reduce the frost-heaving force;

[0034] 3. The device of the present invention is easy to construct, and the disturbance to frozen soil and the environment is small. The device of the present invention undergoes a vertical variable cross-section during operation. The entire device can be prefabricated and assembled in the factory. The construction process is the same as that of the pile foundation, and can be completed through the drilling-hoisting-backfilling process. The area of ​​frozen soil disturbance is small, which allows for rapid construction and is environmentally friendly. This solves the problem that the construction of conventional variable-section frozen heave prevention and control foundations requires excavation, formwork, pouring, and long-term maintenance, and the construction process has a significant impact on frozen ground temperature and environmental disturbances. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a schematic diagram of the overall structure of the frost heave prevention and control device of the present invention (partially installed in the soil).

[0036] Figure 2 This is an axonometric cross-sectional view of the freeze pull prevention and control device of the present invention.

[0037] Figure 3 Schematic diagram of the overall structure of the freeze pull prevention and control device of the present invention (excluding the sleeve).

[0038] Figure 4 Schematic diagram of pile foundation and base structure.

[0039] Figure 5 Schematic diagram of the anchor tube structure.

[0040] Figure 6 This is the axonometric cross-sectional view of the anchor cylinder.

[0041] Figure 7 This is a partial enlarged view (support and card block).

[0042] Figure 8 Schematic diagram of the deformation of the anchor tube during the frost heave period.

[0043] Figure 9 It is a construction flow chart of the present invention.

[0044] Among them, 1: anchoring tube, 101: upper block, 102: lower block, 103: connecting ring, 2: sleeve; 3: pile foundation, 4: base, 5: upper slot, 6: lower slot, 7: block, 8: first blocking block, 9: support, 10: limiting protrusion, 11: second blocking block. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0046] Example 1

[0047] like Figure 1-Figure 7 As shown, a shallow buried self-anchored pile foundation frost heave prevention and control device in a frozen soil area includes an anchor tube 1, a sleeve 2, a pile foundation 3 and a base 4. The pile foundation 3 and the base 4 are installed in the anchor tube 1, and the pile foundation 3 is fixed on the top of the base 4. Specifically, the pile foundation 3 is vertically fixed at the center position of the top of the base 4, and the sleeve 2 is sleeved on the upper part of the anchor tube 1. The sleeve 2 is used to isolate the pile foundation 3 from the frozen soil and reduce the tangential frost heave force.

[0048] The anchor cylinder 1 includes a plurality of upper blocks 101 located in the active layer of the frozen soil area, a plurality of lower blocks 102 located in the frozen soil layer of the frozen soil area, and a connecting ring 103 arranged between the upper blocks 101 and the lower blocks 102. The upper blocks 101 and the lower blocks 102 are arranged correspondingly up and down, and the plurality of upper blocks 101 are arranged evenly spaced. The plurality of upper blocks 101 are enclosed to form a cylindrical structure with a plurality of upper slots 5. Each of the upper slots 5 is arranged between two adjacent upper blocks 101. A plurality of card blocks 7 are fixed on the inner wall of each upper block 101. The plurality of card blocks 7 Located at different heights of the upper block 101, multiple lower blocks 102 are evenly spaced, and the multiple lower blocks 102 are enclosed to form a cylindrical structure with multiple lower slots 6. Each of the lower slots 6 is arranged between two adjacent lower blocks 102. A first positioning block 8 is fixed on the outer edge of the bottom of each lower block 102. The upper slots 5 and the lower slots 6 are arranged correspondingly up and down. The upper block 101 and the lower block 102 are elastic structures. The elastic structure and the arrangement of the upper slots 5 and the lower slots 6 increase the freedom of the anchor tube 1 to deform due to frost heave.

[0049] Furthermore, the lower bottom surface of the sleeve 2 is flush with the lower bottom surface of the connecting ring 103, and the top surface of the sleeve 2 is flush with the top surface of the anchor tube 1 (that is, the top surface of the upper block 101). The lower part of the sleeve 2 is located in the frozen soil layer in the frozen soil area, thereby preventing the soil from entering the anchor tube 1 through the upper groove 5, and at the same time preventing the anchor tube 1 from contacting the soil, thereby reducing the tangential frost heave force.

[0050] Furthermore, the bottom groove wall of the upper groove 5 is the upper top surface of the connecting ring 103 , and the bottom groove wall of the lower groove 6 is the lower bottom surface of the connecting ring 103 .

[0051] A plurality of circles of supports 9 are evenly spaced along the axial direction of the pile foundation 3, and each circle of supports 9 is evenly distributed along the circumference of the pile foundation 3. One end of each support 9 is fixed on the pile foundation 3, and each support 9 extends obliquely upward to the other end and is located below a block 7 (which may contact the inner wall of the upper block 101 or leave a gap), and there is a gap between the block 7 and the support 9. A plurality of limiting protrusions 10 are evenly spaced along the circumference of the base 4, and each limiting protrusion 10 corresponds to a lower slot 6 and fits with the lower slot 6 to limit the anchor cylinder 1. A second blocking block 11 is fixed to the outer edge of the bottom of each limiting protrusion 10. The second blocking block 11 has the same thickness as the first blocking block 8, and the second blocking block 11 and the first blocking block 8 are alternately spaced to form a blocking ring protruding outward.

[0052] Furthermore, the thickness of the limiting protrusion 10 is the same as that of the lower block 102, so that after the limiting protrusion 10 fits into the lower groove 6, multiple limiting protrusions 10 and multiple lower blocks 102 are alternately arranged and spaced to form a cylindrical shape, and the upper top surface of the limiting protrusion 10 contacts the lower bottom surface of the connecting ring 103 (that is, the bottom groove wall of the lower groove 6), and the upper top surface of the base 4 is flush with the upper top surface of the connecting ring 103.

[0053] Furthermore, sleeve 2 is a steel-wire reinforced rubber sleeve with a Teflon coating on its outer surface. This coating is highly hydrophobic and non-sticky. When the surrounding soil freezes, the frozen water cannot adhere to sleeve 2. Furthermore, the Teflon coating has a smooth surface and an extremely low coefficient of friction, further reducing the friction between sleeve 2 and the soil. The combined effect of these mechanisms significantly reduces the upward pull of the entire device caused by tangential frost heave forces.

[0054] Furthermore, the length of the upper block 101 is greater than that of the lower block 102, specifically, the length ratio of the upper block 101 to the lower block 102 is 2:1, which significantly enhances the squeezing force of the first blocking block 8 on the surrounding soil after frost heave deformation.

[0055] Example 2

[0056] like Figures 1-8 As shown, based on Example 1, this embodiment provides a working method of a shallow-buried self-anchored pile foundation freeze-up prevention and control device in a frozen soil area, including the following steps.

[0057] Step 1: After the self-anchored pile foundation freeze-up prevention and control device is installed in the frozen soil area, the second blocking block 11 and the first blocking block 8 engage with the soil to increase the engagement force between the entire device and the soil.

[0058] Step 2: When the shallow layer of the permafrost zone freezes, it triggers the development of frost heave in the surrounding soil, generating tangential frost heave force and horizontal frost heave force on the self-anchored pile foundation frost heave control device; under the action of the horizontal frost heave force, the sleeve 2 undergoes elastic deformation until it squeezes the upper block 101 inward and drives the lower block 102 outward, forming a "seesaw" effect with the connecting ring 103 as the fulcrum. At the same time, the first blocking block 8 is squeezed and inserted into the surrounding soil. This process forms two frost heave control mechanisms: (1) The upper block 101 and the lower block 102 are tilted and deformed, forming a wedge-shaped structure for the anchor tube 1, which increases the pull-out resistance; (2) The first blocking block 8 is squeezed and inserted into the surrounding soil, which increases the frictional resistance between the anchor tube 1 and the soil. The two frost heave control mechanisms work together to increase the anchoring effect of the anchor tube 1 during the frost heave period.

[0059] In step 3, as frost heave continues to develop, the upper block 101 further tilts inward and deforms, the support 9 shrinks toward the pile foundation 3, and the block 7 moves downward as the upper block 101 tilts. The gap between the block 7 and the support 9 gradually decreases until they touch, and the block 7 presses the support 9 downward, causing the pile foundation 3 to withstand downward pressure and prevent the pile foundation 3 from pulling up. During this frost heave process, the base 4 strengthens the stability and anti-freeze pull capability of the pile foundation 3. First, the base 4 is fixedly connected to the pile foundation 3, and together with the support 9, it limits the horizontal displacement of the pile foundation 3 and prevents the pile foundation 3 from tilting. Second, the limiting protrusions 10 arranged around the base 4 can effectively limit the anchor tube 1, preventing it from rotating and moving downward. Third, the second blocking block 11 at the bottom of the base 4 can effectively increase the bite force with the soil, enhancing the ability of the entire device to resist freeze-thaw deformation. Fourth, the base 4, as the base structure of the pile foundation 3, is located in the frozen soil layer below the active layer, avoiding seasonal freeze-thaw effects and providing stable bearing capacity for the pile foundation 3. In summary, the base 4 strengthens the stability and anti-freeze pullout capability of the pile foundation 3 , enabling the shallow buried pile foundation 3 to meet stringent deformation control requirements.

[0060] Example 3

[0061] like Figure 8-Figure 9 As shown, based on Example 1, this embodiment provides a construction method for a shallow-buried self-anchored pile foundation freeze-up prevention and control device in a frozen soil area, comprising the following steps.

[0062] Step 1: prefabricate the structure. All components of the self-anchored pile foundation freeze-up prevention and control device described in Example 1, except for the sleeve 2, are welded and assembled and set aside.

[0063] Step 2, construction preparation: conduct on-site survey to determine the depth of the active layer and geological conditions in the permafrost area, mark the pile positions and clean the site.

[0064] Step 3, positioning of pile foundation 3: Use a total station or GPS to locate the center coordinates of pile foundation 3, mark the excavation range and depth, and check the length of anchor tube 1 according to the frozen soil depth to ensure that the lower end of sleeve 2 is embedded at least 0.5m below the frozen soil layer (stable frozen soil layer) in the frozen soil area.

[0065] Step 4, drilling: Use an auger to drill vertically to the marked range and depth. The diameter of the hole should be 10-15 cm larger than the outer diameter of the anchor tube 1. After drilling, clean the residue at the bottom of the hole and check the integrity of the hole wall to prevent the hole from collapsing and affecting the installation.

[0066] Step 5: Hoist the structure assembled in step 1 until the retaining ring is in close contact with the bottom of the drill hole, and then hoist the sleeve 2 until the bottom surface is flush with the bottom surface of the connecting ring 103.

[0067] Step 6, backfill and compaction: Backfill weak frost-heaving gravel in layers outside the inner sleeve 2 of the borehole to the top of the sleeve 2, with a thickness of each layer ≤ 30 cm. Use a flat plate compactor to compact. Replace the original soil within 0.5 m from the top of the sleeve 2 and compact it so that the backfill body deforms synergistically with the surrounding frozen soil.

[0068] Step 7, completion acceptance: Check the sealing of the sleeve 2, the clearance between the support 9 and the block 7, and the fit between the limit protrusion 10 and the lower slot 6. Perform a static load test to verify the bearing capacity of the entire structure, measure the verticality deviation of the pile foundation 3 (≤1%), and retain construction records and video materials for archiving.

[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A shallow buried self-anchored pile foundation freeze-up prevention and control device in frozen soil areas, characterized in that: It includes an anchoring tube, a sleeve, a pile foundation and a base. The pile foundation and the base are installed in the anchoring tube, the pile foundation is installed on the top of the base, and the sleeve is sleeved on the anchoring tube. The anchoring cylinder includes a plurality of upper blocks located in the active layer of the frozen soil area, a plurality of lower blocks located in the frozen soil layer of the frozen soil area, blocks arranged at different heights on the inner walls of the upper blocks, and a connecting ring arranged between the upper blocks and the lower blocks; the upper blocks and the lower blocks are arranged correspondingly up and down, the plurality of upper blocks are enclosed to form a cylindrical structure with a plurality of upper slots, each of the upper slots is arranged between two adjacent upper blocks, the plurality of lower blocks are enclosed to form a cylindrical structure with a plurality of lower slots, each of the lower slots is arranged between two adjacent lower blocks, and a first blocking block is fixed to the outer edge of the bottom of each lower block; The pile foundation is provided with a plurality of supports evenly spaced along its axial direction, one end of each support is fixed on the pile foundation, each support extends obliquely upward, the other end of each support is located below a clamping block, and there is a gap between each support and the clamping block, and a plurality of limiting protrusions are evenly fixed on the outer wall of the base along its circumference, each limiting protrusion corresponds to a lower slot and fits with the lower slot, and a second clamping block is fixed on the outer edge of the bottom of each limiting protrusion, and the second clamping block and the first clamping block are alternately spaced to enclose a clamping ring protruding outward; A lower slot is correspondingly provided below each upper slot, and the upper and lower blocks are elastic structures; The upper slot opening faces upward, and the bottom slot wall thereof is the upper top surface of the connecting ring; the lower slot opening faces downward, and the bottom slot wall thereof is the lower bottom surface of the connecting ring.

2. The frostbite prevention and control device according to claim 1, characterized in that: The thickness of the limiting protrusion is the same as that of the lower block, so that the limiting protrusion fits in the lower slot. The limiting protrusion and the lower block are alternately arranged at intervals to enclose a cylindrical shape.

3. The frostbite prevention and control device according to claim 1, characterized in that: The upper top surface of the limiting protrusion contacts the lower bottom surface of the connecting ring, and the upper top surface of the base is flush with the upper top surface of the connecting ring.

4. The frostbite prevention and control device according to claim 1, characterized in that: The sleeve is a steel wire reinforced rubber tube sleeve, and the outer wall of the sleeve is coated with Teflon coating.

5. The frostbite prevention and control device according to claim 1, characterized in that: The length of the upper block is greater than the length of the lower block.

6. The construction method of the frozen soil region shallow buried self-anchored pile foundation freeze-up prevention and control device according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1, construction preparation: On-site survey to determine the depth of the active layer and geological conditions in the permafrost area, mark the pile positions and clean the site; Step 2, Pile foundation positioning: Locate the center coordinates of the pile foundation, mark the excavation range and depth, and check the length of the anchor sleeve according to the frozen soil depth to ensure that the lower end of the sleeve is embedded at least 0.5m below the frozen soil layer in the frozen soil area; Step 3, Drilling: Drill vertically to the marked range and depth. The diameter of the hole should be 10-15 cm larger than the outer diameter of the anchor tube. After drilling, clean the residue at the bottom of the hole and check the integrity of the hole wall to prevent the hole from collapsing and affecting the installation. Step 4: hoist the structure of the self-anchored pile foundation freeze-up prevention and control device except the sleeve until the retaining ring is in close contact with the bottom of the drill hole, and then hoist the sleeve until its bottom surface is flush with the bottom surface of the connecting ring; Step 5, backfill and compaction: Backfill weak frost-heaving gravel in layers outside the inner casing of the borehole to the top of the casing, with each layer ≤30cm thick. Use a plate compactor to compact the backfill. Replace the original soil 0.5m away from the top of the casing and compact it to ensure that the backfill and the surrounding frozen soil deform in coordination. Step 6, completion acceptance: Check the sealing of the sleeve, the movable gap between the support and the block, and the fit between the limit protrusion and the lower slot, conduct a static load test to verify the bearing capacity of the entire device, measure the verticality deviation of the pile foundation, and retain construction records and video data for archiving.

7. The construction method according to claim 6, characterized in that: Use total station or GPS to locate the center coordinates of the pile foundation.

8. The construction method according to claim 6, characterized in that: Vertical drilling is performed using an auger.

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