A wind-resistant assembled foundation suitable for a mountainous power transmission tower and an assembling method thereof

Abstract

This invention relates to a wind-resistant prefabricated foundation for transmission towers in mountainous areas and its assembly method, belonging to the field of power engineering technology. It aims to solve the technical problems of existing mountain transmission tower foundations, such as easy loosening due to freeze-thaw cycles, inconvenient construction, insufficient wind resistance, and slope failure caused by soil erosion. The foundation includes a ground surface, a pit, an anchoring mechanism, a wire mesh foundation I, a wire mesh foundation II, a frozen soil adaptive expansion mechanism, a connecting sleeve, a slope protection mechanism, and foundation columns. Each component is prefabricated in the factory and assembled on-site. The anchoring mechanism achieves automatic anchoring, the wire mesh foundations are arranged in reverse to enhance wind resistance, the frozen soil adaptive expansion mechanism uses its own weight to compensate for freeze-thaw gaps and self-locks, and the slope protection mechanism adapts to soil erosion and adheres closely to the soil surface. This invention eliminates the need for complex grouting, is convenient to construct, achieves freeze-thaw adaptation, strong wind resistance, and prevention of soil erosion, requires no secondary manual maintenance, is suitable for complex working conditions in mountainous areas, and extends the service life of the foundation.

Description

Technical Field

[0001] This invention belongs to the field of power engineering technology, and relates to a wind-resistant prefabricated foundation suitable for transmission towers in mountainous areas and its assembly method, especially a wind-resistant prefabricated foundation suitable for transmission towers in high-altitude and cold mountainous areas and its assembly method. Background Technology

[0002] In high-altitude, cold mountainous areas, transmission tower foundations have long faced the dual challenges of complex geology and extreme climate, with the "soil breathing effect" caused by freeze-thaw cycles being particularly fatal. In winter, the expansion of frozen soil exerts enormous compressive force on the foundation, while in spring, thawing and contraction create tiny gaps between the foundation and the soil. This repeated freezing and pulling action causes the foundation to gradually loosen, shift, and even crack and fail, seriously threatening the safety of the power grid. Existing traditional remediation solutions, such as replacing with non-frost-susceptible soil or deepening the burial depth, are not only massive in scale, costly, and time-consuming, but also fail to fundamentally eliminate the underlying risk of foundation loosening caused by thawing-settlement gaps.

[0003] The remoteness and poor transportation in mountainous areas present a dilemma for power transmission tower construction, balancing transportation difficulties with ecological protection. Because large vehicles cannot reach the site, traditional concrete foundation construction relies on manual labor or horses to carry cement and water up the mountain for on-site mixing. This not only leads to soaring transportation costs and low construction efficiency, but also causes significant damage to the fragile mountain ecosystem due to frequent human and animal activity. Although existing gabion technology can utilize on-site crushed stone and soil as filler, alleviating material transportation pressure to some extent, its internal filler is loose and lacks integrity.

[0004] Existing technologies still have significant shortcomings in addressing the aforementioned challenges, making it difficult to balance stability and construction feasibility. Ordinary gabion structures, lacking a prestressing mechanism, cannot form a stable rigid load-bearing system and are ill-suited to effectively resist the enormous uplift forces and overturning moments generated during transmission tower operation, thus failing to meet high load-bearing requirements. Therefore, there is an urgent need for a new basic technology that can fundamentally suppress frost-pull damage and eliminate thaw settlement gaps, while also enabling low-carbon and environmentally friendly construction, to address the core pain points in the construction of transmission lines in high-altitude and cold mountainous areas. Summary of the Invention

[0005] In view of this, in order to solve the problems of existing mountain transmission tower foundations being prone to loosening due to freeze-thaw cycles, inconvenient construction, insufficient wind resistance, and soil erosion leading to slope failure, thus failing to meet the load-bearing requirements of transmission tower foundations, this invention provides a wind-resistant prefabricated foundation suitable for mountain transmission towers and its assembly method.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A wind-resistant prefabricated foundation suitable for power transmission towers in mountainous areas includes a foundation pit trench opened at the top of the foundation surface, an anchoring mechanism fixed inside the foundation pit trench, a wire mesh foundation I bolted to the top of the anchoring mechanism, a wire mesh foundation II connected to the top of the wire mesh foundation I, a frozen soil adaptive expansion mechanism fixed to the top of the wire mesh foundation II, a connecting sleeve connected to the top flange of the frozen soil adaptive expansion mechanism, and a slope protection mechanism fitted on the outer wall of the connecting sleeve.

[0008] The anchoring mechanism, wire mesh foundation I, wire mesh foundation II, frozen soil adaptive expansion mechanism, and the top of the connecting sleeve are all connected by the same foundation column;

[0009] The frozen soil adaptive expansion mechanism includes two transition discs and a conical seat II. The conical seat II is fixedly sleeved on the foundation column. Multiple movable supports are slidably arranged between the two transition discs. The conical seat II is located between the multiple movable supports. When the soil melts and shrinks, creating tiny gaps, the weight of the conical seat II and the tower body drives the movable supports to expand outward and squeeze the soil to fill the gaps, thus achieving freeze-thaw adaptive compensation.

[0010] As a further improvement to the above technical solution:

[0011] The anchoring mechanism includes an anchoring mounting base, a conical seat I, and multiple anchor rods I. The anchoring mounting base has a cavity that matches the conical seat I. The conical seat I is threaded onto the bottom end of the foundation column and slidably positioned within the cavity. The multiple anchor rods I are slidably positioned through the outer wall of the anchoring mounting base. When installing the tower, the weight of the tower drives the conical seat I to move downwards, and the conical inclined surface compresses the anchor rods I into the surrounding soil, thereby improving the foundation's pull-out resistance.

[0012] It also includes a foundation casing, which is fitted inside the foundation pit and covers the outside of the anchoring mechanism. Before installation, the length of the anchor rod I extending out is less than the diameter of the foundation casing. The tapered seat I is driven upward by the inclined surface of the tapered seat I to maintain the initial state. After the anchoring mechanism is installed, the foundation casing is pulled out to prevent the anchor rod I from contacting the soil prematurely.

[0013] Both cage foundation I and cage foundation II include a cage bottom plate, a cage top plate, a grouting corrugated pipe, and a connecting steel cage. The grouting corrugated pipe is fixed between the cage bottom plate and the cage top plate and is sleeved on the foundation column. The connecting steel cage is fixed to the edges of the cage bottom plate and the cage top plate. A cavity is formed between the connecting steel cage, the cage bottom plate, the cage top plate, and the grouting corrugated pipe. The cavity is filled with gravel and soil, which are further compacted under wind vibration to improve wind resistance.

[0014] The cage foundation I and cage foundation II are arranged in opposite directions. The bottom plates of the two cages are attached to each other and fixed with pre-embedded bolts. The joint is sealed with sealant to prevent soil and water from seeping into the cavity and causing the filler to clump and fail. At the same time, it offsets part of the horizontal wind load and enhances the overturning resistance.

[0015] Multiple connecting plates are fixed between the two transition discs, and a sliding channel is formed between two adjacent connecting plates. The movable support is slidably disposed in the sliding channel. A rectangular through hole corresponding to the movable support is opened on the top of the transition disc. A sliding block is slidably disposed in the rectangular through hole. The sliding block is fixed to the top of the movable support and plays a radial limiting role for the movable support to prevent it from deflecting when sliding.

[0016] The frozen soil adaptive expansion mechanism also includes a limiting component, which includes a piston cylinder, a wedge block, and a spring I. The piston cylinder is horizontally fixed inside the conical seat II and corresponds to the movable support. The wedge block is slidably disposed on one side of the piston cylinder and the conical seat II. The spring I is disposed inside the piston cylinder and its two ends abut against the inner wall of the piston cylinder and the wedge block, respectively. The movable support has a slot on its inner side that mates with the wedge block. When the soil freezes and expands in winter, the wedge block is inserted into the slot to achieve self-locking of the movable support and prevent the foundation from loosening.

[0017] Multiple evenly distributed anchor rods II are fixed to the outer wall of the movable support. The ends of the anchor rods II are sharpened. When the movable support expands radially, the anchor rods II are inserted into the soil simultaneously, which enhances the interlocking ability between the movable support and the soil and further improves the stability of the foundation.

[0018] A sealing cover is welded to the top of the upper transfer disc. The sealing cover completely covers the top of the transfer disc, forming a closed protection to prevent rainwater, soil and impurities from entering the frozen soil adaptive expansion mechanism and avoid component corrosion and jamming.

[0019] The slope protection mechanism includes a sliding sleeve. A locking ring is fixedly fitted on the outer wall of the top of the sleeve. Multiple through holes are opened at the top of the sliding sleeve. Guide rods are slidably installed in the through holes. The tops of the multiple guide rods are fixed to the bottom of the locking ring. A slope protection skirt is fixed on the outer wall of the bottom of the sliding sleeve. When the soil is lost, the slope protection skirt slides down the sliding sleeve along the guide rods and fits tightly against the soil surface to prevent the foundation root from becoming hollow.

[0020] The assembly method for wind-resistant prefabricated foundations suitable for transmission towers in mountainous areas, as described above, includes the following steps:

[0021] S1. Excavation of foundation pit and installation of anchoring mechanism: Excavate foundation pit at the top of the foundation surface, hoist the anchoring mechanism into the foundation pit and fix it.

[0022] S2. Installation of the mesh cage foundation connection and the frozen soil adaptive expansion mechanism: Install mesh cage foundation I and mesh cage foundation II, which is connected to mesh cage foundation I in the opposite direction, in sequence on the top of the anchoring mechanism. Seal the connection with sealant. Fill the cavities of the two mesh cage foundations with gravel and soil blocks and compact them in layers. Install the frozen soil adaptive expansion mechanism on the top of mesh cage foundation II to ensure that multiple movable supports are located between the transition discs. Fix the conical seat II on the foundation column that runs through each component.

[0023] S3. Installation and backfilling of upper components: Connect the flange to the docking sleeve at the top of the frozen soil adaptive expansion mechanism, and install the slope protection mechanism on the outer wall of the docking sleeve; fill the gap between each component and the foundation pit with soil, compact it in layers to form a compacted soil layer, and finally install the tower body.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. The wind-resistant prefabricated foundation for power transmission towers in mountainous areas disclosed in this invention adopts a factory prefabrication and on-site assembly mode for all components, eliminating the need for complex on-site grouting processes. This avoids the problems of difficult transportation of grouting equipment and difficulty in ensuring grouting accuracy caused by rugged terrain and inconvenient transportation in mountainous areas. During the installation of the anchoring mechanism, the foundation casing can provide protection for the anchor rod I, ensuring the smooth hoisting and positioning of the anchoring mechanism. At the same time, the anchoring mechanism realizes the automatic extension of the anchor rod I through threaded transmission, eliminating the need for additional power equipment, further simplifying the construction process, reducing the labor intensity of construction personnel, and improving construction efficiency.

[0026] 2. The wind-resistant prefabricated foundation for transmission towers in mountainous areas disclosed in this invention utilizes the synergistic effect of a frozen soil adaptive expansion mechanism. During winter, when the soil freezes and expands, the movable support cannot radially retract due to the self-locking angle of the wedge-shaped block, slot, and conical seat II's inclined surface. This forces the expanding frozen soil to exert a clamping force on the foundation, preventing loosening and displacement. In spring, when the soil thaws and shrinks, creating gaps, the tower's own weight causes the conical seat II to sink, driving the movable support to expand radially. Anchor rod II is simultaneously inserted into the soil to fill the gaps, achieving adaptive compensation for frozen soil thawing settlement. The entire construction process requires no complex grouting, making construction convenient. It achieves freeze-thaw adaptation, strong wind resistance, and prevention of soil erosion, eliminating the need for secondary manual maintenance. It is suitable for complex working conditions in mountainous areas, solving the problem of loosening and cracking of existing foundations due to repeated freeze-thaw cycles, and extending the foundation's service life.

[0027] 3. The wind-resistant prefabricated foundation for transmission towers in mountainous areas disclosed in this invention features a cage foundation I and a cage foundation II arranged in opposite directions to form a stable overall frame. The gravel and soil filling the cage foundation are further compacted under the action of small high-frequency vibrations generated by strong winds in mountainous areas, which improves the overall rigidity of the cage foundation and enhances its resistance to horizontal wind loads. At the same time, the anchor rod I of the anchoring mechanism and the anchor rod II of the movable support are inserted into the soil at different depths to form a double anchoring effect. Combined with the wrapping effect of the compacted soil layer on each component, the foundation's pull-out resistance and overturning resistance are greatly improved, ensuring that the transmission tower remains stable in strong wind environments.

[0028] 4. The wind-resistant prefabricated foundation for power transmission towers in mountainous areas disclosed in this invention features a slope protection structure in which the slope protection skirt can slide down along the guide rods under its own weight, keeping it in close contact with the soil surface. It uses its own weight to compact the remaining soil, preventing the foundation roots from becoming hollow due to soil loss. The drainage channels on the surface of the slope protection skirt can slow down the flow rate of rainwater and reduce the erosion of the surface soil. Combined with the protective effects of the compacted soil layer and the wire mesh foundation, a multi-layer protection system is formed, which completely solves the problem that the soil under the traditional rigid slope protection is easily hollowed out, leading to the slope protection failure due to suspension, and further improves the stability of the foundation.

[0029] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0031] Figure 1 This is a schematic diagram of the installation plan structure of the wind-resistant prefabricated foundation for power transmission towers in mountainous areas according to the present invention;

[0032] Figure 2 This is a three-dimensional structural schematic diagram of the wind-resistant prefabricated foundation for power transmission towers in mountainous areas, as described in this invention.

[0033] Figure 3 This is a cross-sectional view of the sliding sleeve in this invention;

[0034] Figure 4 This is a schematic diagram of the exploded structure of the frozen soil adaptive expansion mechanism in this invention;

[0035] Figure 5 This is a schematic diagram of the assembly structure of the conical seat II and the movable support in this invention;

[0036] Figure 6 This is a schematic diagram of the assembly structure of the cage foundation I, cage foundation II, and anchoring mechanism in this invention;

[0037] Figure 7 This is a schematic diagram of the anchoring mechanism in this invention from a bottom view.

[0038] Attached reference numerals: 1. Foundation surface; 2. Excavation pit; 3. Foundation casing; 4. Anchoring mechanism; 41. Anchor mounting base; 42. Anchor rod I; 43. Conical seat I; 5. Wire mesh cage foundation I; 51. Wire mesh cage bottom plate; 52. Wire mesh cage top plate; 53. Grouting corrugated pipe; 54. Connecting steel cage; 6. Wire mesh cage foundation II; 7. Compacted soil layer; 8. Frozen soil adaptive expansion mechanism; 81. Transition disc; 82. Connecting plate; 8 3. Movable support; 84. Sliding block; 85. Rectangular through hole; 86. Conical seat II; 87. Anchor bolt II; 88. Sealing cover plate; 89. Piston cylinder; 810. Wedge block; 811. Spring I; 812. Slot; 9. Connecting sleeve; 10. Slope protection mechanism; 101. Sliding sleeve; 102. Through hole; 103. Slope protection skirt; 11. Foundation column; 12. Locking ring; 13. Guide rod. Detailed Implementation

[0039] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0040] like Figure 1 , 2 The wind-resistant prefabricated foundation shown is suitable for power transmission towers in mountainous areas. It is adapted to the characteristics of complex mountainous terrain, poor soil stability, and significant winter permafrost expansion and spring thawing settlement. All components are prefabricated in the factory and assembled on site, eliminating the need for complex grouting processes and greatly reducing the difficulty of construction in mountainous areas. It achieves a comprehensive effect of wind resistance, resistance to permafrost deformation, and prevention of soil erosion by relying on the synergistic cooperation of various components.

[0041] In the initial stage of construction, the installation area is leveled, and the bearing capacity of the foundation surface 1 is determined according to the stress requirements of the transmission tower. The surface soil of foundation surface 1 is ensured to be flat and free of loose soil and gravel, providing stable support for subsequent structural installation. Then, a foundation pit 2 is excavated on top of foundation surface 1. The excavation shape of the foundation pit 2 is adapted to the overall outline of the subsequently assembled components. The pit walls must be kept regular, leaving sufficient space for subsequent soil filling and compaction. To prevent the pit sidewalls from collapsing, simple shotcrete protection can be applied to the pit walls to form a dense protective layer to prevent soil erosion.

[0042] After the excavation of the foundation pit 2 is completed, the foundation casing 3 is placed centrally within the pit. The foundation casing 3 is a steel cylindrical structure with a smooth inner wall. Its height is the same as the depth of the foundation pit 2, and its diameter is slightly larger than the maximum outer diameter of the anchoring mechanism 4. Its core function is to provide protective space for the hoisting and positioning of the anchoring mechanism 4, preventing the anchor rod I 42 on the anchoring mechanism 4 from prematurely contacting the soil on the inner wall of the foundation pit 2 during installation, thus preventing the soil from hindering the subsequent expansion and contraction of the anchor rod I 42. The anchoring mechanism 4 is then hoisted into the foundation casing 3. Figure 7 The anchoring mounting base 41 of the anchoring mechanism 4 shown is a cylindrical steel structure. Its bottom is in close contact with the soil at the bottom of the foundation pit 2. Its position is fixed by temporary support components to prevent horizontal displacement of the anchoring mounting base 41 during subsequent assembly and to ensure the assembly accuracy of each component.

[0043] like Figure 6 The anchoring mounting base 41 shown has a pre-reserved cavity that perfectly matches the conical seat I 43, ensuring a tight fit and smooth relative sliding between the two. The inner wall of the conical seat I 43 has internal threads that precisely engage with the external threads at the bottom of the foundation column 11, achieving connection between the conical seat I 43 and the foundation column 11 through threaded transmission. Initially, the conical seat I 43 is positioned at the top until the anchor rod I 42, which penetrates the outer wall of the anchoring mounting base 41, is fully retracted into the mounting base. At this point, the protruding length of the anchor rod I 42 is less than the diameter of the foundation casing 3, ensuring that the anchoring mechanism 4 can be smoothly inserted into the casing without interfering with the inner wall of the casing. The anchor rods I 42 are evenly distributed along the circumference of the anchoring mounting base 41, with sharpened ends to facilitate rapid cutting into the surrounding soil under the pressure of the conical seat I 43, improving the anchoring effect.

[0044] After the anchoring mechanism 4 is fixed in place, the mesh cage foundation I5 is connected to its top via a flange. A sealing gasket is used at the flange connection to enhance the connection's sealing and structural integrity. The mesh cage foundation I5 consists of a bottom plate 51, a top plate 52, a grouting corrugated pipe 53, and a connecting steel cage 54. Both the bottom plate 51 and the top plate 52 are precast reinforced concrete components with internally embedded steel reinforcement to enhance structural strength. Installation holes matching the grouting corrugated pipe 53 are pre-drilled on their surfaces to ensure precise penetration. The grouting corrugated pipe 53 is made of high-strength plastic, possessing good flexibility and anti-aging properties. Its diameter is slightly larger than that of the foundation column 11, ensuring smooth penetration of the foundation column 11 while also providing guidance and protection, preventing direct soil abrasion of the column surface. The connecting steel cage 54 is woven from steel bars to form a mesh frame structure. Its two ends are welded and fixed to the edges of the bottom plate 51 and the top plate 52 of the cage, respectively, so that the cage foundation I5 forms a closed overall frame. The cavity formed inside the frame is used to fill the filler, which improves the deformation resistance and overall weight of the foundation.

[0045] After the installation of cage foundation I5 is completed, cage foundation II6 is connected to its top. The two foundations have identical structures, differing only in their installation direction. This reverse arrangement allows the forces acting on the two cage foundations to cancel each other out, enhancing the overall structure's resistance to overturning. The cage base plate 51 of cage foundation II6 is tightly fitted to the cage base plate 51 of cage foundation I5, secured with pre-embedded bolts. Sealant is used to fill the joint to prevent soil or moisture from seeping into the cavity and to avoid the filler clumping and losing its effectiveness due to moisture. The cavities of both cage foundations II6 and I5 are filled with crushed stone and soil collected on-site in the mountainous area. During filling, the soil is compacted in layers. Utilizing the rigid support of the crushed stone and the dense filling characteristics of the soil, the cage foundations form a solid whole, effectively distributing the vertical load transmitted by the transmission tower and resisting deformation caused by horizontal wind loads.

[0046] The top connection of the cage foundation II6 is as follows Figure 4 The permafrost adaptive expansion mechanism 8 shown is a core component for addressing permafrost thawing and settlement, achieving automatic gap compensation through its structural design. The two transition discs 81 of the permafrost adaptive expansion mechanism 8 are steel discs with sufficient thickness to meet load-bearing requirements. They are fixed to the top plate 52 of the wire mesh foundation II 6 with bolts, ensuring a secure connection and uniform stress distribution. Connecting plates 82, rectangular steel plates, are uniformly welded along the circumference between the upper and lower transition discs 81, serving as separators and guides. A regular sliding channel is formed between adjacent connecting plates 82, and a movable support 83 is placed within the channel, allowing for free radial movement along the channel. The movable support 83 is an arc-shaped steel component with an arc matching the transition disc 81. The number of movable supports 83 is the same as the number of connecting plates 82. The inner side of each movable support 83 is reserved with a slope that fits against the conical seat II 86. The angle of the slope is precisely designed to both drive the expansion when the conical seat II 86 moves downward and meet the self-locking requirement when the frozen soil expands in winter, preventing the movable support 83 from retracting in the opposite direction.

[0047] The top of the adapter disk 81 has rectangular through holes 85 corresponding to the positions of each movable support 83. The size of the rectangular through holes 85 is adapted to the sliding block 84. The sliding block 84 is a steel cube, one end of which is welded and fixed to the top of the movable support 83, and the other end is inserted into the rectangular through hole 85, allowing it to move synchronously with the movable support 83 along the rectangular through hole 85. The limiting effect of the rectangular through holes 85 effectively prevents the movable support 83 from deflecting or tilting during radial movement, ensuring that the movement trajectory of each movable support 83 is precise and consistent, and guaranteeing the synchronous movement of the entire mechanism. A sealing cover plate 88 is welded to the top of the adapter disk 81. The sealing cover plate 88 is a circular steel plate that completely covers the top of the entire adapter disk 81, forming a closed protection to prevent rainwater, soil, or impurities from entering the rectangular through holes 85, and to avoid affecting the flexibility of movement of internal components due to corrosion or jamming.

[0048] The conical seat II 86 is fitted onto the foundation column 11 and fixed to it by welding, allowing the conical seat II 86 to be subjected to force and rise and fall synchronously with the foundation column 11 without relative rotation. Figure 5 The outer wall of the conical seat II 86 shown is conical, closely fitting the inner inclined surface of the movable support 83, ensuring that the axial force is converted into a horizontal force driving the radial expansion of the movable support 83 when the conical seat II 86 moves downward. Inside, corresponding to the position of each movable support 83, is a piston cylinder 89. The piston cylinder 89 is a horizontally arranged steel square tube, containing a spring I 811 and a wedge-shaped block 810. The spring I 811 is a compression spring with stable elastic restoring capability. Its two ends abut against the inner wall of the piston cylinder 89 and the wedge-shaped block 810 respectively, constantly applying an outward thrust to the wedge-shaped block 810, pushing it out of the piston cylinder 89. A sealing ring is fitted at the mating point between the piston cylinder 89 and the wedge-shaped block 810 to prevent rainwater and soil impurities from entering the piston cylinder 89. A slot 812 is provided on the inner side of the movable support 83 corresponding to the position of the wedge block 810. The end of the wedge block 810 near the slot 812 is provided with a chamfered surface. The inner wall of the slot 812 is provided with a limiting step that matches the chamfered surface. The wedge block 810 is inserted into the slot 812 under the action of the spring I 811, thereby limiting and fixing the movable support 83. The limiting step and the chamfered surface cooperate to prevent the wedge block 810 from coming out and to prevent it from displacing under non-stressed conditions. At the same time, due to the action of the wedge, the conical seat II 86 can only move downward relative to the movable support 83 and will not move in the opposite direction. Multiple anchor rods II87 are welded to the outer wall of the movable support 83. The anchor rods II87 are evenly arranged along the length of the movable support 83, and their ends are also sharpened. When the movable support 83 expands radially, the anchor rods II87 can be inserted into the surrounding soil simultaneously, enhancing the interlocking ability between the movable support 83 and the soil, forcing the surrounding soil to be pressed tighter, thereby achieving "the more it freezes and thaws, the tighter it becomes" and improving the fixing effect.

[0049] The top of the frozen soil adaptive expansion mechanism 8 is connected via a flange, as shown below. Figure 3The connecting sleeve 9 shown is a steel cylinder with its inner wall tightly fitted to the outer wall of the foundation column 11. Multiple sliding sleeves 101 are provided on the outer wall of the connecting sleeve 9. The number of sliding sleeves 101 is determined according to the slope protection area and requirements, and they are evenly distributed along the circumference of the connecting sleeve 9. Each sliding sleeve 101 can slide independently up and down along the connecting sleeve 9. A locking ring 12 is welded to the top outer wall of the connecting sleeve 9. The locking ring 12 is an annular steel plate that serves to limit and fix the guide rods 13. Multiple guide rods 13 are vertically fixed at its bottom. The number of guide rods 13 is consistent with the number of through holes 102 on each sliding sleeve 101, and they are evenly arranged along the circumference. The guide rod 13 passes through the through hole 102 at the top of the sliding sleeve 101, forming a sliding fit with the sliding sleeve 101. The constraint of the guide rod 13 ensures that the sliding sleeve 101 can only move up and down along the guide rod 13, preventing rotation or horizontal displacement, thus guaranteeing accurate slope protection positioning. A slope protection skirt 103 is welded to the bottom outer wall of the sliding sleeve 101. The slope protection skirt 103 is a fan-shaped reinforced concrete slab, with multiple pieces spliced ​​into a circle, completely covering the surface of the foundation base 1. Its own weight compacts the surface soil, and the pre-reserved drainage channels on the surface of the slope protection skirt 103 can change the rainwater flow path (not shown in the figure), slowing down the rainwater flow rate, reducing erosion of the surface soil, and preventing soil loosening and loss.

[0050] After all components are assembled, the foundation casing 3 is removed, and the protective constraints on the anchor rod I 42 are released. Then, soil is filled into the gaps between the anchoring mechanism 4, the wire mesh foundation I 5, the wire mesh foundation II 6, the frozen soil adaptive expansion mechanism 8, the connecting sleeve 9, the slope protection mechanism 10, and the foundation surface 1. The soil is compacted in layers to form a compacted soil layer 7. The compacted soil layer 7 can tightly wrap all components to form an overall load-bearing structure, further improving the stability of the foundation, while preventing water from seeping into the internal component connections.

[0051] Subsequently, as the weight increases during the tower installation process, the foundation column 11 drives the conical seat I43 to move downward. The inclined surface of the conical seat I43 contacts the end of the anchor rod I42 and generates a squeezing force, converting the axial downward pressure into a radial thrust. This causes the anchor rod I42 to extend radially along the through hole of the anchor mounting seat 41 and insert into the surrounding soil, achieving a firm connection between the anchoring mechanism 4 and the soil, thereby improving the overall pull-out resistance and overturning resistance of the foundation.

[0052] The sliding parts of this device (including but not limited to anchor rod I 42 and anchor mounting base 41, sliding block 84 and rectangular through hole 85, guide rod 13 and through hole 102) need to be cleaned regularly to remove accumulated dirt and apply anti-rust lubricant to ensure the flexibility of component movement. The maintenance cycle can be adjusted according to the actual conditions of the mountainous environment.

[0053] In practical use, this wind-resistant prefabricated foundation, suitable for power transmission towers in mountainous areas, transmits minute high-frequency vibrations to the transmission towers caused by strong winds. This vibration causes the gravel and soil within the cavities to be squeezed and filled under the vibration, further compacting the foundation, filling the tiny internal gaps, improving the overall rigidity of the cage foundation, and enhancing its resistance to wind loads. During winter, when the soil freezes and expands, the expanding soil exerts a radial compressive force on the movable support 83. At this time, the wedge-shaped block 810 is locked in the slot 812, and together with the self-locking angle of the inclined surface of the conical seat II 86, a reverse constraint is formed, preventing the movable support 83 from radially retracting. This forces the expanding frozen soil to exert a continuous clamping force on the foundation, preventing the foundation from loosening and shifting due to the expansion of the frozen soil. When the soil melts and shrinks in spring, creating gaps, the weight of the tower body is transferred to the foundation column 11 through the transmission tower, causing the conical seat II 86 to sink downwards. The inclined surface of the conical seat II 86 presses against the inner inclined surface of the movable support 83, driving the movable support 83 to expand radially outwards along the channel between the connecting plates 82. The anchor rod II 87 is simultaneously inserted into the surrounding soil until the outer wall of the movable support 83 is tightly attached to the soil, completely filling the gaps caused by soil shrinkage and maintaining the stability of the foundation.

[0054] When heavy rains in mountainous areas cause the surface soil around the foundation to erode and the soil surface to drop, the slope protection skirt 103 loses the support of the surface soil. Under its own weight, it drives the sliding sleeve 101 to slide downwards along the guide rod 13, always keeping it in close contact with the new soil surface. It uses its own weight to continuously compact the remaining soil, preventing the foundation roots from becoming hollow due to soil loss. The drainage channels reserved on the surface of the slope protection skirt 103 can change the rainwater flow path, slow down the rainwater flow rate, and reduce the erosion of the surface soil by rainwater. Combined with the protective effect of the compacted soil layer 7 and the wire mesh foundation, a multi-layer protection system is formed, effectively avoiding the problem of traditional rigid slope protection failing due to the hollowing out of the underlying soil.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A wind-resistant prefabricated foundation suitable for power transmission towers in mountainous areas, characterized in that, An anchoring mechanism (4) is fixed inside the foundation pit (2) opened at the top of the foundation surface (1). The top of the anchoring mechanism (4) is bolted to the cage foundation I (5) and the cage foundation II (6) which is opposite to the cage foundation I (5). The top of the cage foundation II (6) is fixed to the frozen soil adaptive expansion mechanism (8). The top flange of the frozen soil adaptive expansion mechanism (8) is connected to the connecting sleeve (9). The outer wall of the connecting sleeve (9) is fitted with a slope protection mechanism (10). The anchoring mechanism (4), cage foundation I (5), cage foundation II (6), frozen soil adaptive expansion mechanism (8), and connecting sleeve (9) are all installed on the same foundation column (11). The frozen soil adaptive expansion mechanism (8) includes two transition discs (81) and a conical seat II (86) fixedly mounted on the foundation column (11). Multiple movable supports (83) are slidably arranged between the two transition discs (81). The conical seat II (86) is located in the middle area enclosed by the multiple movable supports (83). When the soil melts and shrinks to produce tiny gaps, the movable supports (83) are driven to expand outward and squeeze the soil to fill the gaps by using the weight of the conical seat II (86) and the tower body, thus realizing freeze-thaw adaptive compensation.

2. The wind-resistant prefabricated foundation for transmission towers in mountainous areas according to claim 1, characterized in that, The anchoring mechanism (4) includes an anchoring mounting seat (41), a conical seat I (43), and multiple anchor rods I (42). The anchoring mounting seat (41) has a cavity that matches the conical seat I (43). The conical seat I (43) is threaded onto the bottom end of the foundation column (11) and slidably disposed in the cavity. Multiple anchor rods I (42) are slidably disposed on the outer wall of the anchoring mounting seat (41). When the tower body is installed, the weight of the tower body drives the conical seat I (43) to move downward. The conical inclined surface squeezes the anchor rods I (42) into the surrounding soil, thereby improving the pull-out resistance of the foundation.

3. The wind-resistant prefabricated foundation for transmission towers in mountainous areas according to claim 2, characterized in that, It also includes a foundation casing (3), which is fitted inside the foundation pit trench (2) and covered outside the anchoring mechanism (4). Before installation, the length of the anchor rod I (42) is less than the diameter of the foundation casing (3). The tapered seat I (43) is driven upward by the inclined surface of the tapered seat I (43) to maintain the initial state. After the anchoring mechanism (4) is installed, the foundation casing (3) is pulled out to prevent the anchor rod I (42) from contacting the soil in advance.

4. The wind-resistant prefabricated foundation for transmission towers in mountainous areas according to claim 1, characterized in that, Both the cage foundation I (5) and the cage foundation II (6) include a cage bottom plate (51), a cage top plate (52), a grouting corrugated pipe (53), and a connecting steel cage (54). The grouting corrugated pipe (53) is fixed between the cage bottom plate (51) and the cage top plate (52) and is sleeved on the foundation column (11). The connecting steel cage (54) is fixed to the edge of the cage bottom plate (51) and the cage top plate (52). A cavity is formed between the connecting steel cage (54), the cage bottom plate (51), the cage top plate (52), and the grouting corrugated pipe (53). The cavity is filled with gravel and soil, which are further compacted under wind vibration to improve wind resistance.

5. The wind-resistant prefabricated foundation for transmission towers in mountainous areas according to claim 4, characterized in that, The cage foundation I (5) and cage foundation II (6) are arranged in opposite directions. The cage bottom plates (51) of the two are attached to each other and fixed by pre-embedded bolts. The joint is sealed with sealant to prevent soil and water from seeping into the cavity and causing the filler to clump and fail. At the same time, it offsets part of the horizontal wind load and enhances the overturning resistance.

6. The wind-resistant prefabricated foundation for transmission towers in mountainous areas according to claim 1, characterized in that, Multiple connecting plates (82) are fixed between the two transition discs (81), and a sliding channel is formed between two adjacent connecting plates (82). The movable support (83) is slidably disposed in the sliding channel. A rectangular through hole (85) corresponding to the movable support (83) is opened on the top of the transition disc (81). A sliding block (84) is slidably disposed in the rectangular through hole (85). The sliding block (84) is fixed to the top of the movable support (83) and plays a radial limiting role on the movable support (83) to prevent it from deflecting when sliding.

7. The wind-resistant prefabricated foundation for transmission towers in mountainous areas according to claim 6, characterized in that, The frozen soil adaptive expansion mechanism (8) also includes a limiting component, which includes a piston cylinder (89), a wedge block (810), and a spring I (811). The piston cylinder (89) is horizontally fixed inside the conical seat II (86) and corresponds to the movable support (83). The wedge block (810) is slidably disposed on one side of the piston cylinder (89) and the conical seat II (86). The spring I (811) is disposed inside the piston cylinder (89) and its two ends abut against the inner wall of the piston cylinder (89) and the wedge block (810) respectively. The movable support (83) has a slot (812) on its inner side that cooperates with the wedge block (810). When the soil freezes and expands in winter, the wedge block (810) is inserted into the slot (812) to achieve self-locking of the movable support (83) and prevent the foundation from loosening.

8. The wind-resistant prefabricated foundation for transmission towers in mountainous areas according to claim 7, characterized in that, The movable support (83) has multiple evenly distributed anchor rods II (87) fixed on its outer wall, and a sealing cover plate (88) is welded to the top of the upper transfer disc (81).

9. The wind-resistant prefabricated foundation for transmission towers in mountainous areas according to claim 6, characterized in that, The slope protection mechanism (10) includes a sliding sleeve (101), a locking ring (12) is fixedly fitted on the outer wall of the top of the connecting sleeve (9), a plurality of through holes (102) are opened at the top of the sliding sleeve (101), a guide rod (13) is slidably installed in the through hole (102), the top of the plurality of guide rods (13) is fixedly connected to the bottom of the locking ring (12), and a slope protection skirt (103) is fixedly installed on the outer wall of the bottom end of the sliding sleeve (101). When the soil is lost, the slope protection skirt (103) slides down along the guide rod (13) with the sliding sleeve (101) and sticks tightly to the soil surface to prevent the foundation root from hollowing.

10. The assembly method for wind-resistant prefabricated foundations suitable for transmission towers in mountainous areas, based on claim 1, is characterized in that... Includes the following steps: S1. Excavation of foundation pit and installation of anchoring mechanism (4): Excavate foundation pit (2) on the top of foundation surface, and hoist the anchoring mechanism (4) into the foundation pit (2) and fix it. S2, Installation of the mesh cage foundation docking and the frozen soil adaptive expansion mechanism: Install mesh cage foundation I (5) and mesh cage foundation II (6) which is docked in the opposite direction to mesh cage foundation I (5) in sequence on the top of the anchoring mechanism (4), and seal the docking point with sealant; fill the cavity of the two mesh cage foundations with gravel and soil blocks and compact them in layers; install the frozen soil adaptive expansion mechanism (8) on the top of mesh cage foundation II (6) to ensure that multiple movable supports (83) are located between the transition discs (81), and fix the conical seat II (86) on the foundation column (11) that runs through each component; S3. Installation and backfilling of upper components: Connect the flange of the frozen soil adaptive expansion mechanism (8) to the connecting sleeve (9) and install the slope protection mechanism (10) on the outer wall of the connecting sleeve (9); fill the gap between each component and the foundation pit (2) with soil, compact it in layers and then install the tower body.

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