Anti-frost heaving device for underground structure of transmission tower and control method of anti-frost heaving device

Abstract

The invention relates to the technical field of power transmission tower supporting, in particular to a frost heaving prevention device of a power transmission tower underground structure and a control method thereof.The frost heaving prevention device of the power transmission tower underground structure comprises a tower foundation body, the tower foundation body is inserted into soil during installation, and the tower foundation body comprises an upper part and a lower part; the upper part is of a conical tower-shaped stepped structure, and the small end of the upper part is arranged on the upper part, so that the horizontal frost heaving force can be reduced and guided downwards, the tower foundation main body is more stable, and the phenomenon that the tower foundation main body is pushed to be inclined or a tower collapse accident is caused by the horizontal frost heaving force is avoided; the segmentation reinforcers are configured to cut soil in the radial direction, so that the upward frost heaving force can be reduced, and the tower foundation body is prevented from being pulled out of the ground through the frost heaving force. An anchoring assembly is arranged on each segmentation reinforcing piece, and the anchoring assemblies are configured to be capable of anchoring the tower foundation body in soil.

Description

Technical Field

[0001] This invention relates to the field of power transmission tower support technology, and in particular to an anti-frost heave device and control method for underground structures of power transmission towers. Background Technology

[0002] Against the backdrop of the global energy structure accelerating its transition to renewable energy, offshore wind power has become an important direction for energy development due to its advantages such as abundant resource reserves, stable wind speeds, and no occupation of land space. my country has a long coastline, with technically exploitable offshore wind resources exceeding 2.25 billion kilowatts. In particular, regions such as the Bohai Sea and the northern Yellow Sea not only have abundant wind energy resources but also large areas of seasonal and permafrost. When offshore wind farms are built in these areas, the electricity generated by the offshore wind farms needs to be transmitted to land via submarine cables, requiring long-distance transmission through onshore transmission towers. The stability of the foundations of these transmission towers directly affects the safety and reliability of power transmission.

[0003] In cold, frozen soil regions, transmission tower foundations face a unique threat of frost heave: as sub-zero temperatures set in, moisture in the soil pores gradually freezes, ice crystals grow, causing the soil to expand and resulting in frost heave. During this process, the transmission tower foundation is subjected to the combined effects of horizontal, tangential, and normal frost heave forces. The tangential frost heave force is distributed axially along the sidewall of the transmission tower foundation, while the normal frost heave force is distributed vertically. As the freezing time continues to extend, under the repeated action of the tangential and normal frost heave forces, gaps gradually form between the transmission tower foundation and the underlying soil layer. Simultaneously, the soil around the gap at the bottom of the transmission tower foundation is squeezed and deformed into the gap under the action of the horizontal frost heave force.

[0004] When the warm season arrives, the foundations of offshore wind power transmission towers are typically constructed using building materials with good thermal conductivity, such as reinforced concrete. This heat conduction accelerates the melting of the soil around the foundation, forming soft, plastic thawed soil. Under the load on the foundation and the weight of the soil itself, this soft, plastic soil quickly fills the gaps under the foundation, causing the foundation to be unable to return to its original position during the thawing phase. After a complete freeze-thaw cycle, the foundation undergoes irreversible upward displacement, a phenomenon known as frost pull-out. The cumulative effect of multiple freeze-thaw cycles will continuously increase the amount of frost pull-out, eventually causing the transmission tower to tilt, shift, or even collapse, seriously threatening the stable operation of the offshore wind farm's power transmission system.

[0005] Currently, to address the adverse effects of soil frost heave on the foundations of power transmission towers, passive protective measures such as increasing foundation depth and self-weight are commonly used in engineering practice. However, increasing foundation depth not only increases the excavation depth and construction difficulty, but also, in permafrost regions with complex terrain and harsh geological conditions, can easily damage the fragile permafrost ecosystem, leading to environmental problems such as permafrost degradation and surface subsidence. Increasing foundation self-weight, on the other hand, is difficult to adapt to the dynamic loads generated by the periodic changes in frost heave force during seasonal freeze-thaw cycles. Under long-term repeated loading, the foundation structure is prone to fatigue damage, resulting in a decrease in load-bearing capacity and failing to effectively ensure the long-term safe and stable operation of power transmission towers. Summary of the Invention

[0006] Therefore, it is necessary to provide a frost heave prevention device and control method for underground structures of power transmission towers, which addresses the problem that the foundations of current power transmission towers are susceptible to frost heave in cold regions, leading to a decrease in stability.

[0007] The above objectives are achieved through the following technical solutions: A frost heave prevention device for underground structures of power transmission towers, the frost heave prevention device comprising: The pole foundation body is inserted into the soil during installation. The pole foundation body includes an upper part and a lower part. The upper part is a cone-shaped stepped structure with the smaller end at the top. The lower part is an inverted pyramidal structure. Each cone sidewall of the lower part is provided with a segmented reinforcing member, which is configured to cut the soil radially. Each segmented reinforcing member is provided with an anchoring assembly, which is configured to anchor the pole foundation body into the soil.

[0008] Furthermore, the outer side of the main body of the tower foundation is fitted with an anti-frost heave sleeve.

[0009] Furthermore, the inner circumferential wall of the anti-frost heave sleeve is provided with a heat insulation layer; the anti-frost heave device for the underground structure of the transmission tower also includes a heating system, which is configured to heat the soil when the soil temperature around the main body of the tower foundation is lower than the lower limit of a set temperature range.

[0010] Furthermore, the heating system includes a temperature sensor, a heat source, and a controller. The temperature sensor is configured to acquire the temperature of the soil surrounding the main body of the tower foundation. The heat source is buried in the soil surrounding the main body of the tower foundation and is configured to heat the soil. The controller is configured to receive the temperature signal transmitted by the temperature sensor, and when the soil temperature is lower than the lower limit of the set temperature range, activate the heat source to heat the soil, and when the soil temperature reaches the upper limit of the set temperature range, shut off the heat source.

[0011] Furthermore, the controller includes a wireless communication module configured to communicate with a remote monitoring center.

[0012] Furthermore, the segmented reinforcement has a pyramidal structure with the pointed end facing outwards.

[0013] Furthermore, the anchoring assembly includes an anchor rod and an anchor plate. Each of the segmented reinforcing members has an anchor rod fixedly inserted into it, and the height lines of the anchor rod and the segmented reinforcing member coincide. Each of the anchor rods is fixedly fitted with an anchor plate, and the anchor plate is located in the soil.

[0014] Furthermore, the anti-frost heave sleeve includes a first sub-sleeve and a second sub-sleeve. The first sub-sleeve is a rigid structure and is located below the second sub-sleeve. The second sub-sleeve has a petal-shaped structure and is elastic. A return ring is also sleeved on the outside of the main body of the tower foundation. The return ring is located on the ground. Multiple steel cables are connected between the return ring and the first sub-sleeve. The multiple steel cables are arranged circumferentially and can all form a stop fit with the second sub-sleeve.

[0015] Furthermore, the boundary between the first and second sub-tubes is at the same horizontal level as the boundary between the upper and lower portions.

[0016] This invention also provides a control method for an anti-frost heave device for underground structures of transmission towers, applicable to an anti-frost heave device for underground structures of transmission towers, comprising the following steps: S1. Real-time monitoring of soil temperature around the main body of the tower foundation using temperature sensors; S2. Compare the monitored soil temperature with the set temperature range; S3. When the soil temperature is lower than the lower limit of the set temperature range, the heat source is activated to heat the soil; S4. When the soil temperature reaches the upper limit of the set temperature range, the heat source is turned off; S5. Repeat steps S1 to S4 to keep the soil temperature around the main body of the tower foundation within the set temperature range.

[0017] The beneficial effects of this invention are: This invention relates to an anti-frost heave device and its control method for underground structures of power transmission towers. The control method for the anti-frost heave device for underground structures of power transmission towers includes using an anti-frost heave device to prevent frost heave of the underground structures of power transmission towers. During use, the anti-frost heave device, by setting the upper part of a conical, stepped structure, can reduce and guide the horizontal frost heave force downward when the soil frosts, making the main body of the tower foundation more stable and reducing the horizontal frost heave force from pushing the power transmission tower to tilt or causing a tower collapse accident; by setting the lower part to an inverted pyramid shape... The structure features segmented reinforcements on each conical sidewall of the lower part. When soil frost heaves, these reinforcements break the soil into smaller pieces, reducing tangential frost heave force and preventing it from uprooting the tower foundation. The inverted pyramidal structure of the lower part guides the tangential frost heave force laterally, further reducing it, and also reduces normal frost heave force, preventing it from uprooting the tower foundation. Anchoring components further secure the tower foundation in the soil, enhancing its stability.

[0018] Furthermore, by setting up a heating system, the soil around the main body of the tower foundation can be heated, which can effectively prevent the soil from freezing and thus avoid the occurrence of frost heave.

[0019] Furthermore, by using a controller to automatically control the start and stop of the heat source, its heating power can be automatically adjusted according to changes in ambient temperature, thus saving energy and protecting the environment.

[0020] Furthermore, by including a wireless communication module in the controller, remote monitoring and control can be achieved, facilitating maintenance and management.

[0021] Furthermore, by setting up a heat source buried in the soil between the anti-frost heave sleeve and the main body of the tower foundation, construction is convenient and has little impact on the environment.

[0022] Furthermore, by setting up a first sub-tube, a second sub-tube, a return ring, and a steel cable, when the soil experiences frost heave, the soil causes the second sub-tube to shrink inward. The second sub-tube, through its stop with the steel cable, simultaneously causes the steel cable to tighten. The steel cable simultaneously causes the return ring to move downward, so that the return ring is pressed against the ground around the main body of the tower foundation. This allows the tower foundation to exert a downward force, thereby reducing the upward movement of the tower foundation and improving its stability.

[0023] Furthermore, by setting the boundary between the first and second sub-tubes at the same horizontal level as the boundary between the upper and lower parts, when the second sub-tube contracts inward, the force transmitted through the soil to the second sub-tube can be fully transferred to the upper part, thereby improving the stability of the main structure of the tower foundation. Attached Figure Description

[0024] Figure 1 A three-dimensional structural diagram of the main body of the tower foundation for the frost heave prevention device of the underground structure of the power transmission tower provided in an embodiment of the present invention; Figure 2 A three-dimensional cross-sectional view of the main body of the tower foundation for the frost heave prevention device for the underground structure of the power transmission tower provided in an embodiment of the present invention; Figure 3 A three-dimensional structural schematic diagram of the anti-frost heave device for underground structures of power transmission towers provided in an embodiment of the present invention; Figure 4 This is a front view schematic diagram of the anti-frost heave device for underground structures of power transmission towers provided in an embodiment of the present invention; Figure 5 for Figure 4 Sectional view along the AA direction; Figure 6 for Figure 5 A magnified schematic diagram of the structure at point B in the middle; Figure 7 This is a top view of the anti-frost heave device for underground structures of power transmission towers provided in an embodiment of the present invention.

[0025] in: 1. Main body of the tower foundation; 101. Upper part; 102. Lower part; 2. Segmented reinforcement; 201. Support seat; 3. Anchoring assembly; 301. Anchor bolt; 302. Anchor plate; 4. Anti-frost heave sleeve; 401. First sleeve; 4011. Support ring rib; 40111. Guide groove; 402. Second sleeve; 5. Thermal insulation layer; 601. Heat source; 7. Return ring; 8. Steel cable; 9. Wedge anchor; 10. Mounting plate. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0027] The component designations used in this document, such as "first" and "second," are merely for distinguishing the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage," unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0029] like Figures 1 to 7 As shown, an embodiment of the present invention provides an anti-frost heave device for underground structures of transmission towers, which includes a tower foundation body 1. The tower foundation body 1 is inserted into the soil during installation. The tower foundation body 1 includes an upper part 101 and a lower part 102. The upper part 101 is a cone-shaped stepped structure with the small end at the top. The lower part 102 is an inverted cone-shaped structure. Each cone sidewall of the lower part 102 is provided with a segmented reinforcing member 2. The segmented reinforcing member 2 is configured to cut the soil radially. Each segmented reinforcing member 2 is provided with an anchoring component 3. The anchoring component 3 is configured to anchor the tower foundation body 1 into the soil.

[0030] Specifically, in this embodiment, the main body 1 of the tower foundation adopts a reinforced concrete structure to provide the main support for the transmission tower; the upper part 101 adopts a pagoda-like stepped shape to reduce and guide the horizontal frost heave force downward, preventing the horizontal frost heave force from pushing the tower to the side or causing a tower collapse accident; the upper part 101 adopts a two-layer pagoda-like stepped shape, divided into two layers with different tapers. The first layer is a step to reduce lateral cutting force, and the second layer is a step to reduce lateral cutting force. When horizontal frost heave force is generated due to soil frost heave, these two steps guide the horizontal frost heave force to a downward force, preventing the horizontal frost heave force from pushing the transmission tower to the side or causing a tower collapse accident; the lower part 102 is an inverted four-sided pyramidal structure, which is combined with the segmented reinforcing member 2 to guide the tangential frost heave force to move laterally, reduce the upward frost heave force, and prevent the upward pull force from pushing the main body 1 of the tower foundation out of the ground.

[0031] Furthermore, the projection view of the lower part 102 on the front and rear vertical planes is an inverted triangle, and the base angle of the inverted triangle is at least 60 degrees, ensuring that the lower part 102 has good stress relief performance.

[0032] During use, when the soil experiences frost heave, the horizontal, tangential, and normal frost heave forces generated by the frost heave will act on the main body 1 of the tower foundation. At this time, the conical stepped structure of the upper part 101 of the main body 1 of the tower foundation can effectively decompose and guide the horizontal frost heave force: two layers of steps with different tapers reduce lateral cutting force, converting the horizontal load into a downward component force, which is transmitted to the lower part of the main body 1 of the tower foundation and the deep stable soil layer through the force transmission path of the structure itself. This significantly reduces the lateral thrust of the horizontal frost heave force on the transmission tower, effectively avoiding tower tilting or collapse accidents caused by excessive horizontal thrust, and ensuring the horizontal stability of the main body 1 of the tower foundation.

[0033] Meanwhile, the inverted pyramidal structure of the lower part 102 of the main body 1 of the tower foundation and the segmented reinforcing member 2 work together: In the early stage of soil frost heave, the segmented reinforcing member 2 cuts into the soil radially, breaking the integrity of the soil during frost heave and weakening the transmission path of tangential frost heave force; when the tangential frost heave force acts on the sidewall of the inverted pyramidal structure of the lower part 102, the inclined surface of the inverted pyramidal structure decomposes the tangential frost heave force and guides it to diffuse laterally, reducing the upward pull-out load on the main body 1 of the tower foundation and preventing the frost heave force from pulling the main body 1 of the tower foundation out of the ground; when the normal frost heave force acts on the lower part 102, its inverted pyramidal structure can reduce the upward pull-out load on the main body 1 of the tower foundation and prevent the frost heave force from pulling the main body 1 of the tower foundation out of the ground; at the same time, the gaps formed by the segmented reinforcing member 2 cutting the soil also further reduce the friction between the soil and the sidewall of the main body 1 of the tower foundation, reduce the upward frost heave resistance, and effectively prevent the main body 1 of the tower foundation from being pushed out of the ground due to excessive upward pull-out force.

[0034] Furthermore, the anchoring component 3 firmly connects the main body 1 of the tower foundation to the surrounding soil, increasing the anchoring force between the main body 1 and the soil, thus providing additional pull-out and overturning resistance. When frost heave forces attempt to displace the main body 1, the anchoring component 3 can fully exert its anchoring effect, utilizing the shear strength and friction of the soil to firmly fix the main body 1 of the tower foundation in the soil. Working in conjunction with the upper part 101 and the lower part 102, it comprehensively improves the overall stability of the main body 1 of the tower foundation under frost heave conditions.

[0035] In a further embodiment, to further improve the stability of the main body 1 of the tower foundation, an anti-freeze sleeve 4 is fitted on the outside of the main body 1 of the tower foundation.

[0036] Specifically in this embodiment, the anti-frost heave sleeve 4 is a ring structure and is fitted around the outer periphery of the main body 1 of the tower foundation during installation. Its material is a high-strength and corrosion-resistant metal material, such as stainless steel or aluminum alloy.

[0037] During use, when the soil experiences frost heave, the anti-frost heave sleeve 4 separates the soil around the main body of the tower foundation 1 from the soil outside the anti-frost heave sleeve 4 into two relatively independent stress-bearing areas. This not only blocks the direct transmission of frost heave force generated by the frost heave of the outer soil to the main body of the tower foundation 1, thus reducing the frost heave force on the main body of the tower foundation 1, but also significantly reduces the amount of frost heave deformation of the soil inside the anti-frost heave sleeve 4 due to space constraints. This reduces the effective area of ​​the frost heave force acting on the side wall of the main body of the tower foundation 1, further reducing the frost heave force on the main body of the tower foundation 1. The reduction of frost heave force can prevent the transmission tower from tilting or causing a tower collapse accident, and can also reduce the upward displacement of the main body of the tower foundation 1, thereby improving the stability of the main body of the tower foundation 1.

[0038] In a further embodiment, to effectively prevent frost heave, a heat insulation layer 5 is provided on the inner peripheral wall of the frost heave sleeve 4; the frost heave prevention device for the underground structure of the transmission tower also includes a heating system, which is configured to heat the soil when the soil temperature around the main body of the tower foundation 1 is lower than the lower limit of a set temperature range.

[0039] Specifically in this embodiment, the thermal insulation layer 5 is set between the anti-frost heave sleeve 4 and the main body 1 of the tower foundation, and uses high-efficiency thermal insulation materials, such as polyurethane foam or rock wool, to ensure that the loss of soil heat can be effectively reduced and the soil freezing depth can be reduced.

[0040] Understandably, to improve the waterproofing effect of the thermal insulation layer 5, a thermoplastic polyolefin waterproof membrane or a sodium-based bentonite waterproof blanket can be laid on the outside of the thermal insulation layer 5.

[0041] During use, when the soil temperature around the main body of the tower foundation 1 is lower than the lower limit of the set temperature range, the heating system is activated to heat the soil, which can effectively prevent the soil from freezing and thus avoid the occurrence of frost heave.

[0042] In a further embodiment, the heating system includes a temperature sensor, a heat source 601, and a controller. The temperature sensor is configured to acquire the temperature of the soil surrounding the main body 1 of the tower foundation. The heat source 601 is located in the soil between the anti-frost heave sleeve 4 and the main body 1 of the tower foundation and is configured to heat the soil. The controller is configured to receive the temperature signal transmitted by the temperature sensor and, when the soil temperature is lower than the lower limit of the set temperature range, activate the heat source 601 to heat the soil, and when the soil temperature reaches the upper limit of the set temperature range, deactivate the heat source 601.

[0043] Specifically, in this embodiment, the temperature sensor is inserted into the soil surrounding the main body 1 of the tower foundation during installation and is used to monitor the soil temperature around the main body 1 of the tower foundation, and can transmit the temperature signal to the controller. The lower limit of the set temperature range can be set to -10°C. The heat source 601 is an electric heating cable or carbon fiber heating wire, and is buried in the soil around the main body 1 of the tower foundation for heating the soil. The controller includes a temperature acquisition module, a data processing module, and a control output module. The temperature acquisition module is used to receive the temperature signal transmitted by the temperature sensor; the data processing module is used to process the temperature signal and compare it with the set temperature range; the control output module is used to control the start and stop of the heat source 601 according to the comparison result of the data processing module.

[0044] During use, before the soil temperature around the main body 1 of the tower foundation reaches -10℃, the upper part 101, the lower part 102, the segmented reinforcing member 2, the anchoring component 3, and the anti-frost heave sleeve 4 work together to improve the stability of the main body 1 of the tower foundation. The temperature sensor monitors the soil temperature around the tower foundation in real time and transmits the temperature signal to the temperature acquisition module. The temperature acquisition module transmits the relevant signal to the data processing module. The data processing module compares the signal with the set temperature range and then transmits the comparison result to the control output module. The control output module controls the heat source 601 to be in the off state.

[0045] When the soil temperature around the main body 1 of the tower foundation reaches -10℃, the temperature sensor transmits the temperature signal to the temperature acquisition module. The temperature acquisition module transmits the relevant signal to the data processing module. The data processing module compares the signal with the set temperature range and then transmits the comparison result to the control output module. The control output module controls the heat source 601 to be turned on to heat the soil, thereby effectively preventing the soil from freezing further and avoiding further frost heave.

[0046] In a further embodiment, the controller is configured to also include a wireless communication module, which is configured to communicate with a remote monitoring center, thereby enabling remote monitoring and control, and facilitating maintenance and management.

[0047] In other embodiments, the segmented reinforcement 2 is a pyramidal structure with the pointed end facing outwards.

[0048] Specifically, in this embodiment, the segmented reinforcement 2 is a triangular pyramidal structure. In this way, as the frozen soil moves upward due to frost heave, the segmented reinforcement 2 can cut large pieces of frozen soil into smaller pieces, thereby reducing the frost heave force exerted by the frozen soil on the main body 1 of the tower foundation.

[0049] In other embodiments, the anchoring assembly 3 is configured to include an anchor rod 301 and an anchor plate 302, with an anchor rod 301 fixedly inserted into each segmented reinforcing member 2, and the height lines of the anchor rod 301 and the segmented reinforcing member 2 coinciding; an anchor plate 302 is fixed and sleeved on each anchor rod 301, and the anchor plate 302 is located in the soil.

[0050] Specifically, in this embodiment, the anchor rod 301 and the segmented reinforcing member 2 are cast together with concrete, and the height lines of the anchor plate 302 and the segmented reinforcing member 2 coincide, so that they can be in close contact with the soil at a certain angle, thereby enhancing the pull-out resistance of the main body 1 of the tower foundation.

[0051] Optionally, the anchor plate 302 can be set perpendicular to the anchor rod 301.

[0052] In a further embodiment, to improve the connection strength between the anchor bolt 301 and the segmented reinforcement 2, the segmented reinforcement 2 is configured to have a support 201 made of a metal material, such as stainless steel, and supported at the bottom of all the anchor bolts 301.

[0053] In other embodiments, the anti-frost heave sleeve 4 is configured to include a first sleeve 401 and a second sleeve 402. The first sleeve 401 is a rigid structure and is located below the second sleeve 402. The second sleeve 402 is a petal-shaped structure and is elastic. A return ring 7 is also sleeved on the outside of the main body 1 of the tower foundation. The return ring 7 is located on the ground. Multiple steel cables 8 are connected between the return ring 7 and the first sleeve 401. The multiple steel cables 8 are arranged circumferentially and can all form a stop cooperation with the second sleeve 402.

[0054] Specifically, in this embodiment, to improve the strength of the first spool 401, a plurality of support ring ribs 4011 are coaxially arranged on the inner peripheral wall of the first spool 401, and the plurality of support ring ribs 4011 are arranged at equal intervals along the axial direction; a plurality of guide grooves 40111 are provided on the top of the uppermost support ring rib 40111, and the guide grooves 40111 extend in the radial direction; during installation, the relatively concave part of the second spool 402 is slidably inserted into the guide groove 40111; the steel cable 8 and the relatively concave part of the second spool 402 are correspondingly arranged, and the bottom of the relatively concave part of the second spool 402 abuts against each other to ensure that a stop fit can be formed.

[0055] Furthermore, during installation, the bottom end of the steel cable 8 is fixed to the outer peripheral wall of the first sub-tube 401 by a wedge anchor 9, and the top end is fixed to the top of the return ring 7 by a wedge anchor 9.

[0056] Furthermore, an installation plate 10 is provided between the top of each steel cable 8 and the top of the return ring 7. The installation plate 10 can increase the contact area between the steel cable 8 and the return ring 7, and avoid excessive local pressure, which could cause the return ring 7 to deform.

[0057] During use, when the soil experiences frost heave, the horizontal frost heave force drives the petal-shaped structure of the second sub-tube 402 to contract and deform inward along the guide groove 40111. This generates normal pressure at the contact surface between the sub-tube and the stop of the steel cable 8. According to the principle of force transmission, the steel cable 8 generates axial tension under this pressure. This tension pulls the return ring 7 downward through the top anchor point. The friction between the return ring 7 and the ground, along with its own weight, causes the return ring 7 to press tightly against the ground around the main body of the tower foundation 1, thereby forming a downward pressure constraint on the main body of the tower foundation 1. This effectively inhibits the upward movement of the main body of the tower foundation 1 and improves the stability of the main body of the tower foundation 1 under frost heave conditions.

[0058] In a further embodiment, the boundary between the first sub-tube 401 and the second sub-tube 402 is positioned at the same horizontal level as the boundary between the upper portion 101 and the lower portion 102.

[0059] In actual use, when the soil undergoes frost heave, driving the second cylinder 402 to shrink and deform inward, since the boundary between the first cylinder 401 and the second cylinder 402 is at the same horizontal height as the boundary between the upper part 101 and the lower part 102, the frost heave force transmitted by the second cylinder 402 through the soil can act directly on the cone-shaped stepped structure of the upper part 101 of the main body of the tower foundation 1 with the shortest path and the least loss. According to the principle of force decomposition, the stepped slope of the upper part 101 decomposes the frost heave force into a vertically downward component and a horizontal component. The vertically downward component can effectively offset part of the upward pull-out force caused by frost heave, while the horizontal component diffuses along the stepped surface to the surrounding soil, avoiding concentrated stress that could damage the tower foundation.

[0060] At the same time, the second branch tube 402 is highly aligned with the mechanical action point of the tower foundation body 1, which reduces the eccentric effect in the force transmission process, ensures that the tower foundation body 1 is subjected to uniform force, and improves the overall stability of the tower foundation body 1.

[0061] Another embodiment of the present invention provides a control method for an anti-frost heave device for underground structures of power transmission towers. The method employs an anti-frost heave device for underground structures of power transmission towers and includes the following steps: S1. Real-time monitoring of soil temperature around the main body of the tower foundation 1 using temperature sensors; Specifically, the temperature sensor is buried in the soil around the main body 1 of the tower foundation. It can monitor the soil temperature around the main body 1 of the tower foundation in real time and transmit the temperature signal to the temperature acquisition module.

[0062] S2. Compare the monitored soil temperature with the set temperature range; Specifically, after receiving the temperature signal, the temperature acquisition module transmits the temperature signal to the data processing module. The data processing module compares the temperature signal with the set temperature range and then transmits the comparison result to the control output module.

[0063] S3. When the soil temperature is lower than the lower limit of the set temperature range, heat source 601 is activated to heat the soil. Specifically, the lower limit of the set temperature range can be set to -10℃; the control output module receives the relevant signals transmitted by the data processing module and adjusts the heat source 601 to be in the open state to heat the soil.

[0064] S4. When the soil temperature reaches the upper limit of the set temperature range, turn off the heat source 601; Specifically, the lower limit of the set temperature range can be set to 2℃, and the heat source 601 of the control output module is kept in the off state.

[0065] S5. Repeat steps S1 to S4 to keep the soil temperature around the main body of the tower foundation within the set temperature range.

[0066] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A frost heave prevention device for underground structures of power transmission towers, characterized in that, The anti-frost heave device for the underground structure of the power transmission tower includes: The pole foundation body is inserted into the soil during installation. The pole foundation body includes an upper part and a lower part. The upper part is a cone-shaped stepped structure with the smaller end at the top. The lower part is an inverted pyramidal structure. Each cone sidewall of the lower part is provided with a segmented reinforcing member, which is configured to cut the soil radially. Each segmented reinforcing member is provided with an anchoring assembly, which is configured to anchor the pole foundation body into the soil.

2. The anti-frost heave device for underground structures of transmission towers according to claim 1, characterized in that, The outer side of the main body of the tower foundation is fitted with an anti-freeze sleeve.

3. The anti-frost heave device for underground structures of transmission towers according to claim 2, characterized in that, The inner circumferential wall of the anti-frost heave sleeve is provided with a heat insulation layer; the anti-frost heave device for the underground structure of the transmission tower also includes a heating system, which is configured to heat the soil when the soil temperature around the main body of the tower foundation is lower than the lower limit of a set temperature range.

4. The anti-frost heave device for underground structures of transmission towers according to claim 3, characterized in that, The heating system includes a temperature sensor, a heat source, and a controller. The temperature sensor is configured to acquire the temperature of the soil surrounding the main body of the tower foundation. The heat source is buried in the soil surrounding the main body of the tower foundation and is configured to heat the soil. The controller is configured to receive the temperature signal transmitted by the temperature sensor, and when the soil temperature is lower than the lower limit of the set temperature range, activate the heat source to heat the soil, and when the soil temperature reaches the upper limit of the set temperature range, shut off the heat source.

5. The anti-frost heave device for underground structures of transmission towers according to claim 4, characterized in that, The controller includes a wireless communication module configured to communicate with a remote monitoring center.

6. The anti-frost heave device for underground structures of transmission towers according to claim 1, characterized in that, The segmented reinforcement has a pyramidal structure with the pointed end facing outwards.

7. The anti-frost heave device for underground structures of transmission towers according to claim 1, characterized in that, The anchoring assembly includes an anchor rod and an anchor plate. Each segmented reinforcement member has an anchor rod fixedly inserted into it, and the height lines of the anchor rod and the segmented reinforcement member coincide. Each anchor rod is fixedly fitted with an anchor plate, which is located within the soil.

8. The anti-frost heave device for underground structures of transmission towers according to claim 1, characterized in that, The anti-frost heave sleeve includes a first sleeve and a second sleeve. The first sleeve is a rigid structure and is located below the second sleeve. The second sleeve has a petal-shaped structure and is elastic. A return ring is also sleeved on the outside of the main body of the tower foundation. The return ring is located on the ground. Multiple steel cables are connected between the return ring and the first sleeve. The multiple steel cables are arranged circumferentially and can all form a stop with the second sleeve.

9. The anti-frost heave device for underground structures of transmission towers according to claim 8, characterized in that, The boundary between the first and second sub-tubes is at the same horizontal level as the boundary between the upper and lower portions.

10. A control method for an anti-frost heave device for underground structures of transmission towers, applied to the anti-frost heave device for underground structures of transmission towers as described in claim 4, characterized in that, Includes the following steps: S1. Real-time monitoring of soil temperature around the main body of the tower foundation using temperature sensors; S2. Compare the monitored soil temperature with the set temperature range; S3. When the soil temperature is lower than the lower limit of the set temperature range, the heat source is activated to heat the soil; S4. When the soil temperature reaches the upper limit of the set temperature range, the heat source is turned off; S5. Repeat steps S1 to S4 to keep the soil temperature around the main body of the tower foundation within the set temperature range.

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