A tower foundation structure and construction method for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas

Abstract

The invention discloses a pole tower foundation structure and construction method for preventing and controlling freeze-thaw deformation in seasonal frozen soil areas, wherein the lower part of the pile body in the pole tower foundation structure is connected to the top of the center tube by a hydraulic damper, the outer side of the bottom of the center tube is sleeved with an isolation tube, the conical tube is fixedly connected to the top of the isolation tube, and the conical tube is slidably connected to the outer side of the top of the center tube; an upper oblique support inclined upward and a lower oblique support inclined downward are fixedly connected around the center tube, and the ends of the upper oblique support and the lower oblique support are respectively movably inserted into through holes located on the side walls of the isolation tube; the bottom of the isolation tube is fixedly connected to the base, and a locking pin is fixed on the upper part of the base. The bottom of the center tube is hollow to form a center tube cavity for inserting the locking pin, and the locking pin is slidably connected to the bottom of the center tube through the center tube cavity, and a gap is left between the bottom of the center tube and the base. The hydraulic damper constitutes a first-level control, the upper oblique support and the lower oblique support constitute a second-level control, and the conical tube forms a third-level control. The three work together to realize the whole process control of frost heave and thaw settlement deformation.

Description

Technical Field

[0001] The present invention relates to the technical field of construction for preventing and controlling freeze-thaw deformation of power transmission and transformation facility foundations, and in particular to a pole tower foundation structure and a construction method for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas. Background Art

[0002] my country's seasonally frozen ground areas are widely distributed across Northeast China, North China, Northwest China, and the edge of the Qinghai-Tibet Plateau. These areas are characterized by significant interannual freeze-thaw cycles, characterized by soil expansion during winter and thawing and settling during summer. In recent years, the scale of power transmission and transformation projects in these areas has continued to expand. However, frequent freeze-thaw cycles in these areas cause repeated freeze-heaving and thawing settlement of the soil surrounding tower foundations, leading to foundation uplift, tilting, and even fracture, posing a serious threat to the safe operation of the power grid.

[0003] Traditional tower foundations often utilize shallow buried designs. While this offers the advantages of convenient construction and low cost, it is directly exposed to the active freeze-thaw layer, making it susceptible to frost heave forces generated by soil phase transitions. Current prevention and control technologies primarily focus on two categories: one is to suppress deformation by enhancing the frost resistance of foundation materials (e.g., high-strength concrete, fiber-reinforced composites), but this material cost is high and the effects of frost heave forces cannot be eliminated. The other is to employ deep foundations or thermal insulation measures (e.g., polystyrene insulation layers, gravel replacement). While these measures can partially mitigate frost damage, they significantly increase construction complexity and cost, and are not adaptable in areas with severe frost heave. The current technical bottleneck lies in the excessive pursuit of a "zero-deformation" rigid resistance model for the foundation, while neglecting to optimize the soil-foundation interaction mechanism during freeze-thaw cycles. Traditional structures lack design dissipation for the repeated stresses caused by freeze-thaw cycles, which can easily lead to foundation fatigue damage. Therefore, a new foundation structure that balances cost-effectiveness and reliability is urgently needed. This new foundation structure can achieve active prevention and control of freeze-thaw deformation by reshaping the frost heave force distribution and improving the coordinated deformation capacity of the foundation and frozen soil.

[0004] Based on the concept of "combination of guidance and dredging", this invention breaks through the rigid anti-freeze thinking and proposes a tower foundation that integrates a load-sharing structure. It comprehensively solves the freeze-thaw deformation problem from three dimensions: optimization of the frost heave force transmission path, release of deformation energy and automatic locking, and provides an innovative solution for the long-term and stable operation of power infrastructure in seasonally frozen areas. Summary of the Invention

[0005] The purpose of the present invention is to address the technical defects existing in the prior art and provide a pole tower foundation structure for preventing and controlling freeze-thaw deformation in seasonal frozen soil areas. Through the coordinated action of the hydraulic damping mechanism and the deformation locking mechanism, the freeze-thaw stress of the foundation is effectively reduced and the freeze-thaw deformation of the foundation is alleviated. At the same time, the horizontal frost heave force is better utilized to offset the effect of the tangential frost heave force.

[0006] Another object of the present invention is to provide a construction method for the tower foundation structure.

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

[0008] A tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas comprises a pile body, a hydraulic damper, a tapered tube, an isolation tube, and a central tube, wherein:

[0009] The lower part of the pile body is connected to the top of the central tube through a hydraulic damper. An isolation tube is sleeved on the outer side of the bottom of the central tube. The conical tube is fixedly connected to the top of the isolation tube, and the conical tube is slidably connected to the outer side of the top of the central tube.

[0010] An upper diagonal brace inclined upward and a lower diagonal brace inclined downward are fixedly connected around the central tube. The ends of the upper diagonal brace and the lower diagonal brace are movably inserted into the through holes on the side wall of the isolation tube. The upper diagonal brace and the lower diagonal brace are made of elastic material.

[0011] The bottom of the isolation tube is fixedly connected to the base, a locking pin is fixed to the upper part of the base, the bottom of the central tube is hollow to form a central tube cavity for the locking pin to be inserted, the locking pin is slidably connected to the bottom of the central tube through the central tube cavity, and a gap is left between the bottom of the central tube and the base;

[0012] The isolation cylinder is completely located below the seasonal frozen soil layer, the pile body, the conical cylinder and the hydraulic damper are completely located within the seasonal frozen soil layer, the top of the pile body is flush with the natural ground surface, and the bottom of the conical cylinder is flush with the maximum seasonal freezing depth.

[0013] Another aspect of the present invention further includes a method for operating the tower infrastructure, comprising the following steps:

[0014] When seasonal frozen soil expands, the resulting tangential frost-heave force preferentially acts on the pile, driving it upward. The hydraulic damper activates first, providing resistance in the opposite direction of the frost-heave force, offsetting its influence. When the hydraulic damper reaches the locked state, the pile drives the central tube upward, and the upper diagonal brace begins to take effect. The upper diagonal brace gradually extends from the through-hole of the isolation tube and penetrates the surrounding soil, forming a "barb" anchoring effect. At the same time, the lower diagonal brace retracts into the isolation tube. During the warm-season thaw settlement stage, the thawing soil pulls the pile downward, causing the hydraulic damper to return to its initial position. As thaw settlement continues, the central tube begins to move downward, driven by the pile. At this time, the lower diagonal brace extends from the through-hole and penetrates the surrounding soil, suppressing structural settlement by increasing sidewall friction resistance. When the bottom of the central tube contacts the base, the base provides the final bearing capacity support.

[0015] In the above technical solution, the upper diagonal brace and the lower diagonal brace are made of elastic metal.

[0016] In the above technical solution, the inclination angle of the tapered tube slope is not less than 26.57°.

[0017] In the above technical solution, the upper diagonal braces and lower diagonal braces are alternately fixed in layers on the outside of the central tube. Each layer of upper diagonal braces is composed of N upper support plates inclined upward at the same height, and each layer of lower diagonal braces is composed of N lower support plates inclined downward at the same height.

[0018] In the above technical solution, N is 3 to 6.

[0019] In the above technical solution, N upper support pieces at the same height are evenly distributed outside the central tube in an umbrella shape, and N lower support pieces at the same height are evenly distributed outside the central tube in an umbrella shape.

[0020] In the above technical solution, the hydraulic damper includes a piston body fixed to the bottom of the pile body, a hydraulic chamber formed at the top of the center tube, and multiple damping channels formed on the side wall of the top of the center tube. The piston body is slidably connected to the hydraulic chamber. The hydraulic chamber is divided into an upper hydraulic chamber and a lower hydraulic chamber. The upper hydraulic chamber and the lower hydraulic chamber are filled with antifreeze medium. A sealing ring is fixed on the outer wall of the piston body. The openings at both ends of each damping channel are connected to the hydraulic chamber, and the openings at one end of multiple damping channels are arranged from high to low.

[0021] In the above technical solution, the center lines of the multiple damping channels are located on the same straight line.

[0022] In the above technical solution, each damping channel is an arc-shaped structure.

[0023] In the above technical solution, the cross-sectional area of ​​the upper hydraulic chamber minus the cross-sectional area of ​​the piston body is equal to the cross-sectional area of ​​the lower hydraulic chamber.

[0024] Another aspect of the present invention further includes a construction method of the tower foundation structure, comprising the following steps:

[0025] S1, Construction Preparation: Conduct frozen ground geological survey to understand the seasonal frozen ground characteristics of the site and formulate a construction plan based on this;

[0026] S2, foundation positioning: Use surveying instruments to lay out the site, determine the foundation center position and elevation control points, and mark the installation positions of various structural components;

[0027] S3, Structural Fabrication and Assembly: Prefabricate the main components in the factory, assemble the hydraulic damper on-site and test its sealing performance, weld and fix the upper and lower diagonal braces to the center tube, complete the overall pre-assembly and check the matching dimensions of each component;

[0028] S4, Drilling: Use a rotary drilling rig for pile hole construction. The drill hole diameter must be larger than the designed isolation tube diameter. During the drilling process, the verticality deviation must be strictly controlled, and the hole wall collapse must be dealt with in a timely manner. After the hole is completed, the sediment at the bottom of the hole must be removed to ensure that the hole bottom is flat.

[0029] S5, structure hoisting: Use special hoists for overall hoisting, strictly control the positioning accuracy, and install temporary supports in time after the structure is in place to ensure construction safety;

[0030] S6, pore backfill and compaction: Backfill the improved soil in layers, using small compaction equipment to compact each layer. Pause when backfilling reaches the bottom of the cone, and continue backfilling to the design elevation after verifying the vertical condition of the structure;

[0031] S7, Project Acceptance: Conduct a comprehensive inspection of the structural installation quality, prepare complete construction acceptance records, and complete anti-corrosion treatment.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. This system features multiple levels of control: first, hydraulic dampers, second, upper and lower diagonal braces, and third, tapered cylinders. By redirecting the frost heave force, the system transforms the destructive normal force into a beneficial restraining force. These first, second, and third levels work synergistically to achieve full control of frost heave and thaw deformation.

[0034] 2. The cone, base, and locking pin work together to allow the center tube to move only in a strictly vertical direction, completely eliminating the possibility of lateral tilting and significantly improving the safety and reliability of the tower foundation in complex frozen soil conditions;

[0035] 3. The hydraulic damper's progressive pressurization achieves three key functions: first, it significantly reduces peak frost-uplift forces through hydraulic reaction; second, it effectively dissipates axial tensile stress in the pile foundation; and finally, it prevents excessive pile uplift while allowing controlled displacement. This dynamic balancing mechanism not only protects the structural integrity of the pile but also significantly improves the foundation's stability during repeated freeze-thaw cycles of seasonally frozen soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Shown is a schematic diagram of the overall structure of the present invention.

[0037] Figure 2 It is a schematic diagram of the connection structure of the pile body, hydraulic damper, central tube, upper diagonal brace and lower diagonal brace.

[0038] Figure 3 It is a structural diagram of the tapered cylinder, base and locking pin.

[0039] Figure 4It is a structural diagram of the isolation cylinder.

[0040] Figure 5 It is a cross-sectional view of the present invention.

[0041] Figure 6 It is a cross-sectional view of a hydraulic damper.

[0042] Figure 7 It is a schematic diagram of the frost heave force acting on the inclined surface of the cone.

[0043] Figure 8 It is a flow chart of the construction method of the present invention.

[0044] In the figure: 1. Pile body; 2. Hydraulic damper; 3. Conical cylinder; 4. Isolation cylinder; 5. Base; 6. Damping channel; 7. Upper diagonal brace; 8. Lower diagonal brace; 9. Center cylinder; 10. Center cylinder cavity; 11. Lock pin; 12. Isolation cavity; 13. Upper hydraulic cavity; 14. Lower hydraulic cavity; 15. Piston body; 16. Sealing ring; 17. Through hole. 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 5 As shown, a tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas includes a pile body 1, a hydraulic damper 2, a tapered tube 3, an isolation tube 4, and a central tube 9, wherein:

[0048] The lower part of the pile body 1 is connected to the top of the central tube 9 via a hydraulic damper 2. An isolation tube 4 is sleeved on the outside of the bottom of the central tube 9. The conical tube 3 is fixedly connected to the top of the isolation tube 4. The conical tube 3 is slidably connected to the outside of the top of the central tube 9.

[0049] An upper diagonal brace 7 tilted upward and a lower diagonal brace 8 tilted downward are fixedly connected around the central tube 9. The ends of the upper diagonal brace 7 and the lower diagonal brace 8 are movably inserted into the through holes 17 on the side wall of the isolation tube 4.

[0050] The bottom of the isolation tube 4 is fixedly connected to the base 5, and a locking pin 11 is fixed to the upper part of the base 5. The bottom of the central tube 9 is hollow to form a central tube cavity 10 for inserting the locking pin 11. The locking pin 11 is slidably connected to the bottom of the central tube 9 through the central tube cavity 10, and a gap is left between the bottom of the central tube 9 and the base 5.

[0051] The isolation tube 4 is completely located below the seasonal frozen soil layer, and the pile body 1, the conical tube 3, and the hydraulic damper 2 are completely located within the seasonal frozen soil layer. The top of the pile body 1 is flush with the natural ground surface, and the bottom of the conical tube 3 is flush with the maximum seasonal freezing depth.

[0052] When seasonal frozen soil expands, the resulting tangential frost heave force preferentially acts on pile body 1, driving it upward. Hydraulic damper 2 activates first, providing resistance in the opposite direction of the frost heave force, counteracting its effects. Once hydraulic damper 2 reaches a locked state, pile body 1 drives central tube 9 upward, and upper diagonal brace 7 begins to function. Specifically, upper diagonal brace 7 gradually extends from through-hole 17 in isolation tube 4 and penetrates the surrounding soil, creating a "barb"-like anchoring effect. As frost heave develops, the force exerted on isolation tube 4 increases as upper diagonal brace 7 gradually extends and anchors into the surrounding soil. Simultaneously, lower diagonal brace 8 retracts into isolation tube 4. Both upper and lower diagonal braces 7, 8, are made of elastic metal and maintain elastic deformation throughout their movement, ensuring their reusability. When entering the warm season thawing and settlement stage, the system exhibits adaptive recovery characteristics: first, the soil melts, and the pile body 1 drops under the pull, causing the hydraulic damper 2 to return to its initial position; as the thawing and settlement further develops, the center tube 9 begins to move downward under the drive of the pile body 1. At this time, the lower diagonal brace 8 extends from the through hole 17 and penetrates into the surrounding soil, suppressing the settlement of the structure by increasing the friction resistance of the side wall. When the bottom of the center tube 9 contacts the base 5, the base 5 will provide the final bearing capacity support. It is particularly noteworthy that the elastic restoring forces of the upper and lower diagonal braces 7 and 8 will work together to push the center tube 9 to accurately return to the initial design position. This feature effectively ensures the dimensional stability and durability of the structure in multi-year freeze-thaw cycles. During the entire working process, the upper and lower diagonal braces 7 and 8 form a perfect match with the hydraulic damper, realizing the full process control of frost heave and thaw settlement deformation.

[0053] The mechanical optimization design of the cone 3 achieves a self-locking effect of frost heave force. When the freezing front extends to the buried depth of the cone 3, its unique inclined structure plays a key role: by changing the direction of the frost heave force, the original destructive normal force is converted into a beneficial restraining force. Specifically, Figure 7 As shown in the figure, the frost heave force is decomposed into the normal force on the inclined surface of the cone ( F f ) and tangential force ( F q ), the vertical components of the two F fs 、 F qs There is a clear mechanical relationship. By accurately calculating the inclination angle of the tapered tube, F qs ≤ Ffs The mechanical conditions always hold true;

[0054] ;

[0055] Where: F f is the normal component of the frost heave force on the inclined surface of the cone; F q is the tangential component of the frost heave force on the inclined surface of the cone; θ The angle between the inclined surface of the conical tube and the vertical direction. θ It should be no less than 26.57°. This design cleverly uses the frost heave force itself to achieve automatic locking of the conical tube 3, effectively suppressing the upward displacement of the isolation tube 4, providing a reliable bottom anchoring force for the pile body 1, and significantly improving the stability of the foundation during the frost heave period.

[0056] The structure's anti-overturning stability is ensured by a triple guarantee mechanism consisting of the conical tube 3, the base 5, and the locking pin 11. The spatial constraint principle of the three components is as follows: the central tube 9 is precisely restricted to movement within the internal space of the conical tube 3, while the top of the locking pin 11 penetrates the central tube cavity 10, and the bottom of the locking pin 11 is rigidly connected to the base 5. This nested structural design forms a three-dimensional constraint system, whose mechanical characteristics are as follows: first, the precise fit between the inner wall of the conical tube 3 and the outer wall of the central tube 9 limits horizontal displacement; second, the guiding effect of the locking pin 11 within the central tube cavity 10 ensures the linearity of vertical movement; finally, the fixed connection between the base 5 and the isolation tube 4 provides a stable foundation platform.

[0057] Preferably, the upper and lower diagonal braces 7 and 8 are alternately fixed in layers on the exterior of the central tube 9. Each layer of upper diagonal braces 7 is composed of N upper support pieces at the same height, tilted upward, while each layer of lower diagonal braces 8 is composed of N lower support pieces at the same height, tilted downward. More preferably, N is 3 to 6. The N upper support pieces at the same height are evenly distributed on the exterior of the central tube 9 in an umbrella-like pattern, while the N lower support pieces at the same height are evenly distributed on the exterior of the central tube 9 in an umbrella-like pattern.

[0058] Example 2

[0059] like Figure 6 As shown, this embodiment further optimizes the structure of the hydraulic damper 2 based on the embodiment 1.

[0060] The hydraulic damper 2 includes a piston body 15 fixed to the bottom of the pile body 1, a hydraulic chamber formed at the top of the center tube 9, and multiple damping channels 6 formed on the side wall of the top of the center tube 9. The piston body 15 is slidably connected to the hydraulic chamber. The hydraulic chamber includes an upper hydraulic chamber 13 and a lower hydraulic chamber 14. The upper hydraulic chamber 13 and the lower hydraulic chamber 14 are filled with antifreeze medium. A sealing ring 16 is fixed on the outer wall of the piston body 15. The openings at both ends of each damping channel 6 are connected to the hydraulic chamber. The openings at one end of multiple damping channels 6 are arranged from high to low. Preferably, the center lines of multiple damping channels 6 are located on the same straight line.

[0061] The cross-sectional area of ​​the upper hydraulic chamber 13 minus the cross-sectional area of ​​the piston body 15 equals the cross-sectional area of ​​the lower hydraulic chamber 14. This ensures that when the piston body 15 moves, the volume changes of the upper hydraulic chamber 13 and the lower hydraulic chamber 14 are equal, ensuring the normal movement of the piston body 15.

[0062] When the tangential frost heave force acts on the pile body 1 , the pile body 1 drives the piston body 15 to slide upward in the hydraulic damper 2 , compressing the antifreeze medium in the upper hydraulic chamber 13 . The antifreeze medium in the upper hydraulic chamber 13 enters the damping channel 6 through one end opening of the damping channel 6 and flows out from the other end opening into the lower hydraulic chamber 14. In this embodiment, three damping channels 6 are provided. More preferably, each damping channel 6 is an arc-shaped structure. In the initial stage of freeze drawing, the center line of the piston body 15 is located on the center line of the damping channel 6. One end opening of each damping channel 6 is located in the upper hydraulic chamber 13, and the other end opening is located in the lower hydraulic chamber 14. Antifreeze medium flows in the three damping channels 6. As freeze drawing further occurs, the piston body 15 rises, and the number of damping channels 6 with openings located on the upper part of the piston body 15 decreases, that is, the number of damping channels 6 for the circulation of antifreeze medium decreases, first reducing to two damping channels 6 for the circulation of antifreeze medium, and then reducing to one. In this process, the resistance gradually increases, and the pressure of the antifreeze medium in the upper hydraulic chamber 13 acting on the piston body 15 gradually increases.

[0063] During the entire freeze-pulling process, thanks to the incompressible characteristics of the antifreeze medium and the damping effect of the damping channel 6, a progressive pressurization process is formed in the upper hydraulic chamber 13. This pressure reacts to the pile body 1 through the piston body 15, generating an anchoring force in the opposite direction of the frost heave force, thereby effectively decomposing and offsetting the impact of the frost heave force. During the continuous action of the frost heave force, the system exhibits intelligent response characteristics: as the pile body 1 slowly rises, the sealing ring 16 moves synchronously with the piston body 15, gradually closing the damping channel 6 in a preset order. This progressive closing mechanism ensures that the system's damping force increases with increasing displacement. When all damping channels 6 are completely closed, the system reaches a force balance state and the piston body 15 stops moving.

[0064] In the initial stage of frost heave, when all the damping channels 6 of the hydraulic damper 2 are completely closed and the piston body 15 reaches a locked state, as the frost heave force continues to act, the pile body 1 will drive the central tube 9 to move upward as a whole.

[0065] Example 3

[0066] like Figure 7 As shown, the construction method of the tower foundation structure for preventing and controlling freeze-thaw deformation in seasonal frozen soil areas includes the following steps:

[0067] S1. Construction Preparation: Before construction, a detailed geological survey of seasonal frozen ground is required to understand the characteristics of the site's seasonal frozen ground. Based on the survey results, a special construction plan is developed, necessary construction equipment and materials are prepared, and technical instructions are provided to the construction personnel.

[0068] S2, Foundation Positioning: Use surveying instruments to lay out the site and determine the foundation center and elevation control points. Mark the installation locations of each structural component to ensure accurate positioning.

[0069] S3, structural fabrication and assembly: prefabricate the main components in the factory and assemble on site. The assembly process is to first assemble the hydraulic damper 2, then weld the upper diagonal brace 7 and the lower diagonal brace 8 to the outside of the central tube 9, assemble the isolation tube 4, and then weld the isolation tube 4 to the base 5, and finally weld the tapered tube 3 to complete the overall pre-assembly and check the matching dimensions of each component.

[0070] S4, Drilling: Use a rotary drilling rig to construct the pile hole. The drill hole diameter should be slightly larger than the designed isolation tube diameter. Strictly control vertical deviation during drilling and promptly address any problems such as hole wall collapse. After drilling, remove any sediment from the bottom of the hole to ensure a smooth, level hole bottom.

[0071] S5, Structure Hoisting: Use special hoisting equipment for overall hoisting, strictly control the positioning accuracy. After the structure is in place, install temporary supports in a timely manner to ensure construction safety.

[0072] S6, Pore Backfill and Compaction: Backfill the modified soil in layers, using small compaction equipment to compact each layer. Pause backfilling at the bottom of the cone and verify the verticality of the structure before continuing backfilling to the design elevation.

[0073] S7, Project Acceptance: Conduct a comprehensive inspection of the structural installation quality, including geometric dimensions, mechanical properties, etc. Complete construction acceptance records and complete finishing work such as anti-corrosion treatment.

[0074] 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 tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas, characterized in that: It includes pile body, hydraulic damper, conical cylinder, isolation cylinder and central cylinder, among which: The lower part of the pile body is connected to the top of the central tube through a hydraulic damper. An isolation tube is sleeved on the outer side of the bottom of the central tube. The conical tube is fixedly connected to the top of the isolation tube, and the conical tube is slidably connected to the outer side of the top of the central tube. An upper diagonal brace inclined upward and a lower diagonal brace inclined downward are fixedly connected around the central tube. The ends of the upper diagonal brace and the lower diagonal brace are movably inserted into the through holes on the side wall of the isolation tube. The upper diagonal brace and the lower diagonal brace are made of elastic material. The bottom of the isolation tube is fixedly connected to the base, a locking pin is fixed to the upper part of the base, the bottom of the central tube is hollow to form a central tube cavity for the locking pin to be inserted, the locking pin is slidably connected to the bottom of the central tube through the central tube cavity, and a gap is left between the bottom of the central tube and the base; The isolation cylinder is completely located below the seasonal frozen soil layer, the pile body, the conical cylinder and the hydraulic damper are completely located within the seasonal frozen soil layer, the top of the pile body is flush with the natural ground surface, and the bottom of the conical cylinder is flush with the maximum seasonal freezing depth.

2. The tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas according to claim 1, characterized in that: The upper diagonal brace and the lower diagonal brace are made of elastic metal.

3. The tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas according to claim 1, characterized in that: The inclination angle of the tapered tube slope is not less than 26.57°.

4. The tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas according to claim 1, characterized in that: The upper and lower diagonal braces are alternately fixed on the outside of the central tube in layers, and each layer of upper diagonal braces is composed of N upper support pieces inclined upward at the same height, and each layer of lower diagonal braces is composed of N lower support pieces inclined downward at the same height.

5. The tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas according to claim 4, characterized in that: N is 3~6.

6. The tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas according to claim 4, characterized in that: N upper supporting pieces at the same height are evenly distributed outside the central tube in an umbrella shape, and N lower supporting pieces at the same height are evenly distributed outside the central tube in an umbrella shape.

7. The tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas according to claim 1, characterized in that: The hydraulic damper includes a piston body fixed to the bottom of the pile body, a hydraulic chamber formed at the top of the center tube, and multiple damping channels formed on the side wall of the top of the center tube. The piston body is slidably connected to the hydraulic chamber. The hydraulic chamber is divided into an upper hydraulic chamber and a lower hydraulic chamber. The upper hydraulic chamber and the lower hydraulic chamber are filled with antifreeze medium. A sealing ring is fixed on the outer wall of the piston body. The openings at both ends of each damping channel are connected to the hydraulic chamber, and the openings at one end of multiple damping channels are arranged from high to low.

8. The tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas according to claim 1, characterized in that: The center lines of the multiple damping channels are located on the same straight line, and each damping channel is an arc-shaped structure.

9. The tower foundation structure for preventing and controlling freeze-thaw deformation in seasonally frozen soil areas according to claim 7, characterized in that: The cross-sectional area of ​​the upper hydraulic chamber minus the cross-sectional area of ​​the piston body is equal to the cross-sectional area of ​​the lower hydraulic chamber.

10. The construction method of the tower foundation structure according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, Construction Preparation: Conduct frozen ground geological survey to understand the seasonal frozen ground characteristics of the site and formulate a construction plan based on this; S2, foundation positioning: Use surveying instruments to lay out the site, determine the foundation center position and elevation control points, and mark the installation positions of various structural components; S3, Structural Fabrication and Assembly: Prefabricate the main components in the factory, assemble the hydraulic damper on-site and test its sealing performance, weld and fix the upper and lower diagonal braces to the center tube, complete the overall pre-assembly and check the matching dimensions of each component; S4, Drilling: Use a rotary drilling rig for pile hole construction. The drill hole diameter must be larger than the designed isolation tube diameter. During the drilling process, the verticality deviation must be strictly controlled, and the hole wall collapse must be dealt with in a timely manner. After the hole is completed, the sediment at the bottom of the hole must be removed to ensure that the hole bottom is flat. S5, structure hoisting: Use special hoists for overall hoisting, strictly control the positioning accuracy, and install temporary supports in time after the structure is in place to ensure construction safety; S6, pore backfill and compaction: Backfill the improved soil in layers, using small compaction equipment to compact each layer. Pause when backfilling reaches the bottom of the cone, and continue backfilling to the design elevation after verifying the vertical condition of the structure; S7, Project Acceptance: Conduct a comprehensive inspection of the structural installation quality, prepare complete construction acceptance records, and complete anti-corrosion treatment.

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