Working method of shallow-buried self-anchored pile foundation freezing and pulling prevention and control device in permafrost region

Abstract

The invention discloses a working method of a frozen soil area shallow-buried self-anchored pile foundation freezing and pulling prevention and control device, the frozen soil area shallow-buried self-anchored pile foundation freezing and pulling prevention and control device comprises an anchoring cylinder, a sleeve, a pile foundation and a base, the pile foundation and the base are installed in the anchoring cylinder, the pile foundation is installed at the top of the base, and the anchoring cylinder is sleeved with the sleeve; through the arrangement of the upper block, the lower block, the upper open groove and the lower open groove of the anchoring barrel, the effect of changing the cross section in real time according to frost heaving development is provided for the anchoring barrel. Meanwhile, the stress condition of the pile foundation in the frost heaving period is optimized through the synergistic effect of the clamping blocks and the supports, when the upper block inclines inwards and deforms in the frost heaving period, the supports are extruded to contract towards the pile foundation, the gaps between the clamping blocks and the supports are gradually reduced till the clamping blocks make contact with the supports, the clamping blocks press the supports downwards, the supports apply downward force to the pile foundation, and the pile foundation is prevented from being pulled upwards. In addition, the stability and the anti-freezing and anti-pulling capacity of the pile foundation are enhanced through the base, and the shallow-buried pile foundation is promoted to meet the strict deformation control requirement.

Description

[0001] This invention application is a divisional application of the parent application "A device for preventing and controlling the frost pull-out of shallow-buried self-anchored pile foundations in permafrost areas and a construction method thereof", the application number of the parent application is 2025108551176, and the application date is June 25, 2025. Technical Field

[0002] This invention relates to the field of construction technology for frost pull-out prevention and control of shallow pile foundations, and in particular to a frost pull-out prevention and control device and construction method for shallow buried self-anchored pile foundations in permafrost areas. Background Technology

[0003] The unique climatic and geological conditions of permafrost regions pose severe challenges to pile foundation engineering. During seasonal transitions, the repeated freezing and thawing of the soil, resulting in frost pull-out effects, can severely impact pile foundation stability, leading to deformation of the superstructure or even engineering accidents. To address this issue, the engineering community commonly employs increasing pile depth to resist frost pull-out forces by leveraging the anchoring effect of deeper soil layers. While this traditional method is theoretically sound, it has significant limitations in practical application: for projects with lighter loads and shallower foundation depths, excessive depth not only drastically increases material usage but also significantly raises construction difficulty and project costs, failing to meet both economic and practical requirements.

[0004] Currently, the frost pull-out control technologies used in engineering practice mainly include physical isolation, soil improvement, drainage and seepage prevention, and structural reinforcement. While these methods can be effective under certain conditions, they each have significant shortcomings: some have complex construction processes and demanding operating conditions; some have unstable control effects and are difficult to adapt to complex permafrost environments; and others have excessively high costs, making them unsuitable for large-scale promotion. This is especially true in shallow pile foundation projects where deformation control is critical, where the applicability of existing technologies is even more inadequate. Therefore, developing a new type of pile foundation structure that can effectively control frost pull-out deformation while also possessing advantages such as simple construction and economic rationality has become a key technical challenge that urgently needs to be addressed in current engineering construction in permafrost regions.

[0005] In view of this, the present invention proposes a frost pull-out prevention and control device and construction method for shallow buried self-anchored pile foundations in permafrost areas. By utilizing horizontal frost heave force and the radial compression deformation of the structure itself, a self-anchored anti-frost pull-out structure is formed, providing an innovative solution for the prevention and control of diseases in shallow pile foundations. Summary of the Invention

[0006] The purpose of this invention is to address the technical deficiencies in the existing technology by providing a frost pull-out prevention and control device for shallow buried self-anchored pile foundations in permafrost areas. This device utilizes the compression of shallow horizontal frost heave force to achieve the function of vertical cross-section variation, thereby forming a wedge-shaped self-anchoring mechanism, effectively alleviating the problem of frost pull-out disease in shallow buried pile foundations.

[0007] Another objective of this invention is to provide a construction method for the above-mentioned shallow-buried self-anchored pile foundation frost pull-out control device in permafrost areas.

[0008] The technical solution adopted to achieve the purpose of this invention is:

[0009] A shallow-buried self-anchored pile foundation frost pull-out control device for frozen soil areas includes an anchoring cylinder, a sleeve, a pile foundation, and a base. The pile foundation and the base are installed inside the anchoring cylinder, the pile foundation is installed on top of the base, and the sleeve is fitted onto the anchoring cylinder.

[0010] The anchoring cylinder includes multiple upper grids located in the active layer of the permafrost zone, multiple lower grids located in the permafrost layer of the permafrost zone, as well as locking blocks and connecting rings disposed between the upper and lower grids; the upper and lower grids are arranged vertically and vertically, the multiple upper grids enclose to form a cylindrical structure with multiple upper slots, each of the upper slots is disposed between two adjacent upper grids, multiple locking blocks are disposed at different heights on the inner wall of each upper grid, the multiple lower grids enclose to form a cylindrical structure with multiple lower slots, each of the lower slots is disposed between two adjacent lower grids, and a first locking block is fixed on the bottom outer edge of each lower grid;

[0011] Multiple supports are evenly spaced along the axial direction on the pile foundation. One end of each support is fixed to the pile foundation. Each support extends upward at an angle, and the other end is located below a locking block with a gap between it and the locking block. Multiple limiting protrusions are evenly fixed along the circumference on the outer wall of the base. Each limiting protrusion corresponds to a lower slot and fits into the lower slot. A second locking block is fixed to the bottom outer edge of each limiting protrusion. The second locking blocks and the first locking blocks are alternately spaced to form an outwardly protruding locking ring.

[0012] In the above technical solution, a lower slot is provided below each upper slot, and the upper and lower blocks are elastic structures.

[0013] In the above technical solution, the upper slot opening faces upward, and its bottom slot wall is the upper top surface of the connecting ring; the lower slot opening faces downward, and its bottom slot wall is the lower bottom surface of the connecting ring.

[0014] In the above technical solution, the thickness of the limiting protrusion is the same as the thickness of the lower grid, so that the limiting protrusion fits into the lower slot. The limiting protrusion and the lower grid 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.

[0015] 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.

[0016] In the above technical solution, the length of the upper guard is greater than the length of the lower guard.

[0017] Another aspect of the present invention includes a method for operating the shallow-buried self-anchored pile foundation frost pull-out control device in permafrost areas, comprising the following steps:

[0018] Step 1: When the shallow layer of the permafrost zone freezes, it triggers the development of frost heave in the surrounding soil, generating tangential and horizontal frost heave forces on the self-anchored pile foundation frost pull-out control device. Under the action of the horizontal frost heave force, the sleeve undergoes elastic deformation until it squeezes the upper grid inward and drives the lower grid outward. With the connecting ring as the fulcrum, a "seesaw" effect is formed, and at the same time, the first locking block is squeezed and inserted into the surrounding soil.

[0019] Step 2: As frost heave continues to develop, the upper grid further tilts and deforms inward, the support shrinks towards the pile foundation, and the locking block moves downward as the upper grid tilts. The gap between the locking block and the support gradually decreases until they come into contact. The locking block presses down on the support, and the pile foundation bears the downward pressure, preventing the pile foundation from being pulled up.

[0020] In the above technical solution, when the surrounding soil is frost-susceptible, the limiting protrusion is inserted into the frozen soil layer to limit the anchoring cylinder.

[0021] In the above technical solution, the second locking block engages with the surrounding soil, and the base serves as the foundation structure of the pile foundation, preventing the pile foundation from being pulled up.

[0022] 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 permafrost layer of the permafrost region.

[0023] Another aspect of the present invention includes a construction method for a shallow-buried self-anchored pile foundation frost pull-out control device in permafrost areas, comprising the following steps:

[0024] Step 1, Construction Preparation: On-site investigation to determine the depth of the active layer and geological conditions in the permafrost area, mark the pile positions and clear the site;

[0025] Step 2, Pile foundation positioning: Locate the center coordinates of the pile foundation, mark the excavation range and depth, and verify the length of the anchoring sleeve according to the frost depth to ensure that the lower end of the sleeve is embedded at least 0.5m below the frost layer in the frost zone;

[0026] Step 3, Drilling: Drill vertically to the marked range and depth. The diameter of the drilled hole should be 10-15cm larger than the outer diameter of the anchor cylinder. 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.

[0027] Step 4: Hoist the structure of the self-anchored pile foundation frost pull-out control device except for the sleeve until the locking ring is in close contact with the bottom of the borehole, and then hoist the sleeve until the bottom surface is flush with the bottom surface of the connecting ring.

[0028] Step 5, backfilling and compaction: Backfill weakly frost-susceptible gravel in layers outside the casing inside the borehole to the top of the casing, with each layer being ≤30cm thick. Compact the layers with a plate compactor. Replace the original soil within 0.5m from the top of the casing and compact it to ensure that the backfill deforms in tandem with the surrounding frozen soil.

[0029] Step 6, final acceptance: Check the sealing performance of the sleeve, the clearance between the support and the locking block, and the fit between the limiting 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 (≤1%), and archive construction records and video data.

[0030] In the above technical solution, a total station or GPS is used to locate the center coordinates of the pile foundation.

[0031] In the above technical solution, a spiral drilling rig is used for vertical drilling.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. The upper and lower grids, upper and lower slots of the anchoring cylinder of the present invention provide the anchoring cylinder with the function of real-time cross-section variation according to frost heave development. At the same time, the synergistic effect of the locking block and the support optimizes the stress conditions of the pile foundation during the frost heave period. When the upper grid tilts and deforms inward during the frost heave period, it compresses the support and causes it to contract towards the pile foundation. The gap between the locking block and the support gradually decreases until they come into contact. The locking block presses down on the support, and the support applies a downward force to the pile foundation to prevent the pile foundation from being pulled up. Moreover, the base enhances the stability and frost pull-out resistance of the pile foundation, enabling shallow-buried pile foundations to meet stringent deformation control requirements.

[0034] 2. The device of the present invention uses weakly frost-susceptible gravel backfilled between the hole and the borehole wall to further alleviate frost pull-out deformation of the pile foundation. First, the backfill soil has weak frost-susceptibility characteristics; its own frost heave is negligible. Deformation and displacement only occur due to the frost heave of the soil outside the borehole wall, forming a deformation buffer layer between the natural soil and the structure, thus reducing the intensity of frost heave development around the pile. On the other hand, the backfill soil is gravel, a coarse-grained filler with a relatively large particle size, significantly reducing the contact and friction between the soil and the sidewall of the structure. Therefore, backfilling with weakly frost-susceptible gravel can directly reduce frost pull-out force.

[0035] 3. The device of this invention is simple to construct, with minimal disturbance to frozen soil and the environment. During operation, the device undergoes vertical cross-section changes. The entire device can be prefabricated and assembled in a factory, with a construction process similar to pile foundations, completed through drilling-hoisting-backfilling. This minimizes frozen soil disturbance, enabling rapid construction and is environmentally friendly. It solves the problem that conventional variable cross-section frost-pull control foundation construction requires excavation, formwork, pouring, and long-term curing, resulting in significant impacts on frozen soil temperature and the environment. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of the frost-pull control device of the present invention (partially installed in the soil).

[0037] Figure 2 This is an isometric sectional view of the frost prevention and control device of the present invention.

[0038] Figure 3 This is a schematic diagram of the overall structure of the freeze-pull prevention device of the present invention (without the sleeve).

[0039] Figure 4 This is a schematic diagram of the pile foundation and base structure.

[0040] Figure 5 This is a schematic diagram of the anchoring cylinder structure.

[0041] Figure 6 This is an isometric sectional view of the anchor cylinder.

[0042] Figure 7 This is a magnified view of a section (supports and blocks).

[0043] Figure 8 This is a schematic diagram of the deformation of the anchor cylinder during the frost heave period.

[0044] Figure 9 This is a flowchart illustrating the construction process of the present invention.

[0045] Among them, 1: anchoring cylinder, 101: upper grid, 102: lower grid, 103: connecting ring, 2: sleeve; 3: pile foundation, 4: base, 5: upper slot, 6: lower slot, 7: locking block, 8: first locking block, 9: support, 10: limiting protrusion, 11: second locking block. Detailed Implementation

[0046] 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 merely illustrative of the invention and are not intended to limit the invention.

[0047] Example 1

[0048] like Figures 1-7 As shown, a shallow-buried self-anchored pile foundation frost heave control device for frozen soil areas includes an anchoring cylinder 1, a sleeve 2, a pile foundation 3, and a base 4. The pile foundation 3 and the base 4 are installed inside the anchoring cylinder 1, and the pile foundation 3 is fixed to the top of the base 4. Specifically, the pile foundation 3 is vertically fixed to the center position of the top of the base 4. The sleeve 2 is sleeved on the upper part of the anchoring cylinder 1. The sleeve 2 is used to isolate the pile foundation 3 from the frozen soil and reduce tangential frost heave force.

[0049] The anchoring cylinder 1 includes multiple upper grids 101 located in the active layer of the permafrost region, multiple lower grids 102 located in the permafrost layer of the permafrost region, and a connecting ring 103 disposed between the upper grids 101 and the lower grids 102. The upper grids 101 and the lower grids 102 are arranged vertically and vertically, with the multiple upper grids 101 evenly spaced. The multiple upper grids 101 enclose each other to form a cylindrical structure with multiple upper slots 5. Each upper slot 5 is disposed between two adjacent upper grids 101. Multiple locking blocks 7 are fixed on the inner wall of each upper grid 101. Multiple lower grids 102 are evenly spaced at different heights of the upper grid 101, forming a cylindrical structure with multiple lower slots 6. Each lower slot 6 is located between two adjacent lower grids 102, and a first locking block 8 is fixed on the bottom outer edge of each lower grid 102. The upper slots 5 and lower slots 6 are arranged vertically and vertically. The upper grid 101 and lower grid 102 are elastic structures. The elastic structure and the arrangement of the upper slots 5 and lower slots 6 increase the degree of freedom of the anchoring cylinder 1 to deform due to frost heave.

[0050] 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 cylinder 1 (i.e., the top surface of the upper grid 101). The lower part of the sleeve 2 is located in the frozen soil layer of the frozen soil area, thereby preventing soil from entering the anchor cylinder 1 through the upper slot 5, and at the same time preventing the anchor cylinder 1 from contacting the soil, thereby reducing the tangential frost heave force.

[0051] Furthermore, the bottom wall of the upper slot 5 is the upper top surface of the connecting ring 103, and the bottom wall of the lower slot 6 is the lower bottom surface of the connecting ring 103.

[0052] Multiple rings of supports 9 are evenly spaced along the axial direction of the pile foundation 3. Each ring of supports 9 is evenly distributed around the circumference of the pile foundation 3. One end of each support 9 is fixed to the pile foundation 3. Each support 9 extends upward at an angle to the other end, which is located below a locking block 7 (it can contact the inner wall of the upper grid 101 or leave a gap). There is a gap between the support 9 and the locking block 7. Multiple limiting protrusions 10 are evenly spaced along the circumference of the outer wall of the base 4. Each limiting protrusion 10 corresponds to a lower slot 6 and fits into the lower slot 6 to limit the anchoring cylinder 1. A second locking block 11 is fixed to the bottom outer edge of each limiting protrusion 10. The second locking block 11 has the same thickness as the first locking block 8. The second locking block 11 and the first locking block 8 are alternately spaced to form an outwardly protruding locking ring.

[0053] Furthermore, the thickness of the limiting protrusion 10 is the same as the thickness of the lower grid 102, so that after the limiting protrusion 10 fits into the lower slot 6, multiple limiting protrusions 10 and multiple lower grids 102 are alternately arranged to form a cylindrical shape. 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 slot 6), and the upper top surface of the base 4 is flush with the upper top surface of the connecting ring 103.

[0054] Furthermore, the sleeve 2 is a steel wire reinforced rubber sleeve with a Teflon coating on its outer wall. The Teflon coating has strong hydrophobicity and non-stick properties, so when the surrounding soil freezes, water cannot adhere to the sleeve 2. In addition, the Teflon coating has a smooth surface and an extremely low coefficient of friction, further reducing the friction between the sleeve 2 and the soil. The combined effect of these mechanisms significantly weakens the upward pull force of the tangential frost heave on the entire device.

[0055] Furthermore, the length of the upper baffle 101 is greater than the length of the lower baffle 102, specifically, the length ratio of the upper baffle 101 to the lower baffle 102 is 2:1, which significantly enhances the compressive force of the first positioning block 8 on the surrounding soil after frost heave deformation.

[0056] Example 2

[0057] like Figures 1-8 As shown in Example 1, this example provides a working method for a shallow-buried self-anchored pile foundation frost pull-out control device in permafrost areas, including the following steps:

[0058] Step 1: After the self-anchored pile foundation frost pull-out control device is installed in the frozen soil area, the second locking block 11 and the first locking block 8 engage with the soil to increase the engagement force between the entire device and the soil.

[0059] Step 2: When the shallow layer of the frozen soil freezes, it causes the surrounding soil to develop frost heave, generating tangential and horizontal frost heave forces on the self-anchored pile foundation frost pull-out control device. Under the action of the horizontal frost heave force, the sleeve 2 undergoes elastic deformation until it squeezes the upper grid 101 to tilt inward and drives the lower grid 102 to tilt outward. With the connecting ring 103 as the fulcrum, a "seesaw" effect is formed. At the same time, the first locking block 8 is squeezed and inserted into the surrounding soil. This process forms two frost pull-out control mechanisms: (1) The tilting deformation of the upper grid 101 and the lower grid 102 makes the anchoring cylinder 1 form a wedge structure, which increases the pull-out resistance; (2) The squeezing and insertion of the first locking block 8 into the surrounding soil increases the frictional resistance between the anchoring cylinder 1 and the soil. The two frost pull-out control mechanisms work together to increase the anchoring effect of the anchoring cylinder 1 during the frost heave period.

[0060] Step 3: As frost heave continues, the upper retaining wall 101 further tilts and deforms inward, the support 9 contracts towards the pile foundation 3, and the locking block 7 moves downward as the upper retaining wall 101 tilts. The gap between the locking block 7 and the support 9 gradually decreases until they contact each other. The locking block 7 presses down on the support 9, and the pile foundation 3 bears the downward pressure, preventing the pile foundation 3 from being pulled upward. During this frost heave process, the base 4 strengthens the stability and frost pull-out resistance of the pile foundation 3. First, the base 4 is fixedly connected to the pile foundation 3, working together with the support 9 to limit the horizontal displacement of the pile foundation 3 and prevent the pile foundation 3 from tilting. Second, the limiting protrusions 10 set around the base 4 can effectively limit the anchoring cylinder 1, preventing the anchoring cylinder 1 from rotating and moving downward. Third, the second locking block 11 set at the bottom of the base 4 can better increase the interlocking force with the soil, enhancing the overall device's resistance to freeze-thaw deformation. Fourth, as the base structure of the pile foundation 3, the base 4 is located in the frozen soil layer below the active layer, avoiding seasonal freeze-thaw effects, and can provide stable bearing capacity for the pile foundation 3. In summary, the base 4 enhances the stability and frost resistance of the pile foundation 3, enabling the shallow-buried pile foundation 3 to meet stringent deformation control requirements.

[0061] Example 3

[0062] like Figures 8-9 As shown, based on Example 1, this example provides a construction method for a shallow-buried self-anchored pile foundation frost pull-out control device in permafrost areas, including the following steps:

[0063] Step 1: Prefabrication of the structure. All components of the self-anchored pile foundation frost pull-out prevention device described in Example 1, except for the sleeve 2, are welded and assembled for later use.

[0064] Step 2, 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 clear the site.

[0065] Step 3, Pile Foundation 3 Positioning: Use a total station or GPS to locate the center coordinates of pile foundation 3, mark the excavation range and depth, and verify the length of anchor cylinder 1 according to the frost depth to ensure that the lower end of sleeve 2 is embedded at least 0.5m below the frost layer (stable frost layer) in the frost zone.

[0066] Step 4, Drilling: Use a auger to drill vertically to the marked range and depth. The diameter of the drilled hole should be 10-15cm larger than the outer diameter of the anchor cylinder 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.

[0067] Step 5: Hoist the structure assembled in Step 1 until the locking ring is in close contact with the bottom of the borehole, and then hoist the sleeve 2 until its bottom surface is flush with the bottom surface of the connecting ring 103.

[0068] Step 6, backfilling and compaction: Backfill weakly frost-susceptible gravel in layers outside the inner sleeve 2 of the borehole to the top of the sleeve 2, with each layer being ≤30cm thick. Compact the layers with a plate compactor. Replace the original soil within 0.5m from the top of the sleeve 2 and compact it to ensure that the backfill deforms in tandem with the surrounding frozen soil.

[0069] Step 7, final acceptance: Check the sealing performance of sleeve 2, the movement gap between support 9 and locking block 7, and the fit between limiting protrusion 10 and lower slot 6. Conduct static load test to verify the bearing capacity of the entire structure, measure the verticality deviation of pile foundation 3 (≤1%), and retain construction records and image data for archiving.

[0070] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A working method for a shallow-buried self-anchored pile foundation frost pull-out control device in permafrost areas, characterized in that, The shallow-buried self-anchored pile foundation frost pull-out control device in the frozen soil area includes an anchoring cylinder, a sleeve, a pile foundation and a base. The pile foundation and the base are installed inside the anchoring cylinder, the pile foundation is installed on top of the base, and the sleeve is fitted onto the anchoring cylinder. The anchoring cylinder includes multiple upper grids located in the active layer of the permafrost region, multiple lower grids located in the permafrost layer of the permafrost region, locking blocks set at different heights on the inner wall of the upper grids, and connecting rings set between the upper and lower grids; the upper and lower grids are arranged vertically and vertically, the multiple upper grids enclose to form a cylindrical structure with multiple upper slots, each of the upper slots being set between two adjacent upper grids, the multiple lower grids enclose to form a cylindrical structure with multiple lower slots, each of the lower slots being set between two adjacent lower grids, and a first locking block is fixed on the bottom outer edge of each lower grid; Multiple supports are evenly spaced along the axial direction on the pile foundation. One end of each support is fixed to the pile foundation. Each support extends upward at an angle. The other end of each support is located below a locking block. There is a gap between each support and the locking block. Multiple limiting protrusions are evenly fixed along the circumference on the outer wall of the base. Each limiting protrusion corresponds to a lower slot and fits into the lower slot. A second locking block is fixed to the bottom outer edge of each limiting protrusion. The second locking blocks and the first locking blocks are alternately spaced to form an outwardly protruding locking ring. Each upper slot has a corresponding lower slot below it, and the upper and lower grids are elastic structures. The upper slot faces upward, and its bottom slot wall is the upper top surface of the connecting ring; the lower slot faces downward, and its bottom slot wall is the lower bottom surface of the connecting ring. The working method includes the following steps: Step 1: When the shallow layer of the permafrost zone freezes, it triggers the development of frost heave in the surrounding soil, generating tangential and horizontal frost heave forces on the self-anchored pile foundation frost pull-out control device. Under the action of the horizontal frost heave force, the sleeve undergoes elastic deformation until it squeezes the upper grid inward and drives the lower grid outward. With the connecting ring as the fulcrum, a "seesaw" effect is formed, and at the same time, the first locking block is squeezed and inserted into the surrounding soil. Step 2: As frost heave continues to develop, the upper grid further tilts and deforms inward, the support shrinks towards the pile foundation, and the locking block moves downward as the upper grid tilts. The gap between the locking block and the support gradually decreases until they come into contact. The locking block presses down on the support, and the pile foundation bears the downward pressure, preventing the pile foundation from being pulled up.

2. The working method according to claim 1, characterized in that, When the surrounding soil undergoes frost heave, the limiting protrusion is inserted into the frozen soil layer to limit and anchor the cylinder.

3. The working method according to claim 1, characterized in that, The second locking block engages with the surrounding soil, and the base serves as the foundation structure of the pile, preventing the pile from being pulled up.

4. The working method according to claim 1, characterized in that, The bottom surface of the sleeve is flush with the bottom surface of the connecting ring, and the lower part of the sleeve is located in the permafrost layer of the permafrost region.

5. The working method according to claim 1, characterized in that, The thickness of the limiting protrusion is the same as the thickness of the lower grid, so that the limiting protrusion fits into the lower slot.

6. The working method according to claim 1, characterized in that, The limiting protrusions and the lower guard are alternately arranged to form a cylindrical shape.

7. The working method 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.

8. The working method according to claim 1, characterized in that, The sleeve is a steel wire reinforced rubber tube sleeve.

9. The working method according to claim 1, characterized in that, The outer wall of the sleeve is coated with Teflon.

10. The working method according to claim 1, characterized in that, The length of the upper guard is greater than the length of the lower guard.

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