Truss prestressed inclined anchor rod foundation and construction method thereof

Abstract

The present application relates to the technical field of power transmission tower structure design, and discloses a truss prestressed inclined anchor rod foundation and a construction method thereof, the truss prestressed inclined anchor rod foundation comprises a truss pile cap assembly, anchor rods, a pressure bearing connecting structure and a pre-tensioning assembly; the anchor rods are in sliding connection with the truss pile cap assembly, a plurality of anchor rods are symmetrically arranged with the truss pile cap assembly as a central axis, and the included angle θ between the anchor rods and the vertical direction satisfies 15°≤θ≤45°; the pressure bearing connecting structure comprises an anchoring hole and a pressure bearing plate, the pressure bearing plate is fixed to one end of the anchoring hole away from the truss pile cap assembly, and part of the anchor rods is embedded in the anchoring hole and connected with the pressure bearing plate; the pre-tensioning assembly is connected with the other end of the anchor rods to apply prestress to the anchor rods. According to the present application, the anchor rods and the truss pile cap assembly are in sliding connection, the prestress of the anchor rods is no longer constrained by the truss pile cap assembly, and the risk of node weakness, cracking and failure is avoided; and the included angle interval between the anchor rods and the vertical direction takes into account the horizontal force sharing efficiency and the vertical anchoring bearing capacity.

Description

Technical Field

[0001] This invention relates to the field of power transmission tower structural design technology, specifically to a truss prestressed inclined anchor foundation and its construction method. Background Technology

[0002] Compression anchors are a type of anchoring system that converts tensile force into pressure on the grout through a bottom bearing plate. Compared to tension anchors that are bonded along their entire length, compression anchors place the grout under pressure during operation, making them less prone to cracking and providing better corrosion resistance. Furthermore, the radial volume expansion of the grout under pressure increases the frictional resistance between the grout and the rock strata, resulting in superior load-bearing capacity and deformation performance compared to tension anchors.

[0003] Unlike industries such as construction and transportation, the foundations of power transmission line towers bear not only alternating tensile and compressive loads, but also significant horizontal loads. Uplift resistance and overturning resistance are often the control conditions for design verification.

[0004] In related technologies, an integral support platform is set at the top of the anchor bolt, with the anchor bolt arranged vertically or slightly inclined. The support platform needs to be embedded in the bedrock to a certain depth to resist the horizontal force transmitted from the top of the tower base. However, since the foundation of the transmission line needs to withstand both uplift force and horizontal force simultaneously, and the existing support platform type rock anchor foundation requires the support platform to be embedded in the bedrock to a sufficient depth to resist the horizontal force, the existing anchor bolt and support platform are rigidly connected, making it impossible to apply controllable prestress to the anchor bolt. As a result, the transmission line foundation undergoes significant deformation in the early stages of loading. Under the action of horizontal force, the connection node between the anchor bolt and the support platform bears additional bending moment and shear force, weakening the axial tensile advantage of the anchor bolt and making the node a weak point. Summary of the Invention

[0005] This invention provides a truss prestressed inclined anchor foundation and its construction method to solve the problem that it is impossible to apply controllable prestress to the anchor and the axial tensile advantage of the anchor is weakened.

[0006] In a first aspect, the present invention provides a truss prestressed inclined anchor foundation, comprising a truss base assembly, anchor rods, a pressure-bearing connection structure, and a pretensioning assembly; the truss base assembly is adapted to be connected to a tower leg; the anchor rods are slidably connected to the truss base assembly, and multiple anchor rods are inclinedly arranged along the vertical direction, the multiple anchor rods being axially symmetrically arranged about the truss base assembly, the angle between the anchor rods and the vertical direction being θ, satisfying 15°≤θ≤45°; the pressure-bearing connection structure includes an anchor hole and a pressure plate, the anchor hole being adapted to be opened on a rock base surface, the pressure plate being fixed to the end of the anchor hole away from the truss base assembly, a portion of the anchor rod being embedded in the anchor hole and connected to the pressure plate; the pretensioning assembly is connected to the other end of the anchor rod to apply prestress to the anchor rod.

[0007] Beneficial effects: By symmetrically and obliquely arranging multiple anchor rods, the horizontal force borne by the prestressed truss anchor foundation can be decomposed into axial tension and vertical component force, keeping the anchor rods under axial tension at all times. This prevents large deformation of the prestressed truss anchor foundation in the early stages of loading. The vertical component force is borne by the truss foundation assembly and the bedrock. The anchor rods and truss foundation assembly adopt a sliding connection, eliminating the additional bending moment and shear force at the connection node caused by rigid connections in related technologies. The prestressing of the anchor rods is no longer constrained by the truss foundation assembly, avoiding the risk of weak nodes that are prone to cracking and failure. The angle range between the anchor rod and the vertical direction balances the efficiency of horizontal force distribution and vertical anchoring bearing capacity. The lower limit of the angle ensures that the anchor rod has sufficient horizontal component force to resist the horizontal thrust caused by wind load and broken wire load, while the upper limit avoids excessive anchor rod inclination angle, which would lead to severe loss of vertical pull-out bearing capacity. This adapts to the design requirements of transmission tower foundations with different load ratios.

[0008] In one alternative embodiment, the truss platform assembly includes a truss platform and a connecting device, the truss platform being connected to the connecting device, the truss platform being adapted to connect to a tower leg, and the connecting device being slidably connected to the anchor bolt.

[0009] Beneficial effects: The truss pier is responsible for connecting to the tower leg and centrally transferring the load. Through the connecting device, the anchor rod can slide freely relative to the truss pier. During the prestressing process, the axial displacement of the anchor rod is not constrained by the pier, resulting in small prestress loss and high control accuracy.

[0010] In one optional embodiment, the connecting device includes an outer sleeve, an inner sliding sleeve, and a seal. The inner sliding sleeve is fitted onto the anchor rod and is slidably disposed within the outer sleeve. The seal is disposed between the inner sliding sleeve and the outer sleeve.

[0011] Beneficial effects: The connecting device adopts a three-layer sliding structure consisting of an outer sleeve, an inner sliding sleeve, and a sealing element. The outer sleeve is rigidly fixed to the truss foundation node plate, serving as the external support base of the connecting device, ensuring stable stress and no deformation. The inner sliding sleeve is directly fitted onto the outer surface of the anchor rod. When the anchor rod is tensioned, the upward extension and contraction of the anchor rod only causes the inner sliding sleeve to shift relative to the outer sleeve. The foundation is not constrained by the tension force and will not generate additional bending moment or local crushing deformation due to prestress. After the prestress is locked, the long-term stress loss is significantly reduced. A sealing element is installed between the inner and outer sleeve layers to prevent particle jamming and sliding failure, while also isolating corrosive media from contacting the exposed anchor rod, extending the service life of the anchor rod.

[0012] In one optional embodiment, the inner diameter of the inner sleeve is D1, and the diameter of the anchor rod is D2, satisfying 2mm≤D1-D2≤4mm.

[0013] Beneficial effects: Limiting the diameter difference between the inner sleeve and the anchor rod to 2mm to 4mm ensures that there is no significant frictional resistance during axial sliding of the anchor rod under tension and load deformation, allowing for precise and controllable prestressing application. It also limits the lateral displacement of the anchor rod, preventing bending stress on the rod. If the gap is less than 2mm, the anchor rod is prone to dry friction with the inner wall of the inner sleeve, resulting in high resistance during tensioning, causing deviations in prestressing application, additional prestress loss, and long-term reciprocating sliding wear down the anchor rod's anti-corrosion protective layer, accelerating corrosion. If the gap is greater than 4mm, the anchor rod will experience significant lateral displacement within the inner sleeve under horizontal loads. Excessive displacement will cause the rod to compress the end of the inner sleeve, creating localized stress concentration and generating additional bending shear force.

[0014] In one optional embodiment, the truss platform includes horizontal bars and supporting trusses. The horizontal bars are arranged in two layers at intervals along the vertical direction. Multiple supporting trusses are arranged. The supporting trusses are connected to the outer sleeve. One end of the supporting truss is connected to one layer of the horizontal bars, and the other end of the supporting truss is connected to another layer of the horizontal bars.

[0015] Beneficial effects: The truss foundation adopts a spatial combination structure with two layers of horizontal bars arranged at intervals and multiple supporting trusses. The multiple supporting trusses form a stable spatial force system between the two layers of horizontal bars.

[0016] In one optional embodiment, the anchor bolt includes an anchoring part, a free part, a connecting part, and a tensioning part, wherein the anchoring part, the free part, the connecting part, and the tensioning part are connected in sequence, the anchoring part is connected to the bearing plate, the anchoring part and the free part are embedded in the anchoring hole, the free part is spaced apart from the hole wall of the anchoring hole, the connecting part is slidably connected to the truss support assembly, and the tensioning part is connected to the pre-tensioning assembly.

[0017] Beneficial effects: The anchor rod is divided into four functional sections along its length: anchorage section, free section, connection section, and tensioning section. The anchorage section is embedded in the bottom of the anchorage hole and rigidly connected to the bearing plate. During tensioning, the tension is directly transferred to the bearing plate, realizing the force transmission of the pressure-type anchor rod. The free section is spaced apart from the wall of the anchorage hole, leaving a buffer space to allow the anchor rod to produce small lateral displacements under horizontal loads. The connection section passes through the sliding connection device of the truss foundation, transmitting axial tension and isolating bending moment and shear force, eliminating the problem of weak connection between the foundation and the anchor rod. The tensioning section is connected to the pre-tensioning component to realize the prestressing loading of the anchor rod.

[0018] In one optional embodiment, the pressure-bearing connection structure further includes a grout structure, which is poured into the anchoring hole, and the grout structure, the pressure-bearing plate, and the anchoring part are connected to form a grouting anchoring section.

[0019] Beneficial effects: The grout structure is injected into the bottom of the anchoring hole, and the grout, bearing plate, and anchoring part of the anchor rod together form the grouting anchoring section, which has high compressive strength and micro-expansion characteristics; when the pre-tensioning component applies prestress to the anchor rod or the tower transmits the pull-out load, the tension of the anchor rod is transmitted downward to the bearing plate, and the bearing plate forms uniform compressive stress on the grout structure. The grout under pressure is not prone to penetrating cracks, and it isolates the anchoring section from groundwater and air erosion, significantly improving long-term corrosion resistance; the grout structure integrally wraps the anchoring part of the anchor rod and the bearing plate, realizing uniform load transfer and no stress concentration among the anchor rod, bearing plate, and bedrock.

[0020] In one optional embodiment, the pressure-bearing connection structure further includes a particle-filled structure disposed between the free portion and the wall of the anchoring hole, the particle-filled structure having a buffer space.

[0021] Beneficial effects: By setting a granular filling structure between the free part and the wall of the anchor hole, and reserving buffer deformation space inside, the anchor rod can achieve small lateral displacement. The particles can slide relative to each other and buffer deformation, which will not generate reverse constraint shear force on the anchor rod body, ensuring that all horizontal load components are transmitted only along the axial direction of the anchor rod.

[0022] In one alternative embodiment, the angle θ between the anchor rod and the vertical direction satisfies 20°≤θ≤30°.

[0023] Secondly, the present invention also provides a construction method for a truss prestressed inclined anchor foundation, applicable to the construction of the aforementioned truss prestressed inclined anchor foundation, comprising the following steps: S1. Determine the angle θ between the anchor rod and the vertical direction based on the ratio of the horizontal force to the vertical force borne by the truss prestressed inclined anchor rod foundation; S2. Based on the angle θ between the anchor rod and the vertical direction, the anchor hole is opened on the rock base surface; S3. Connect the pressure plate and the anchor rod, place the pressure plate and the anchor rod together into the anchor hole, and fix the pressure plate; S4. Install the truss support assembly on the rock base surface, and slide the anchor rod to the truss support assembly; S5. Install the pretensioning assembly, and pretension and fix the anchor rod according to the design prestress value of the anchor rod.

[0024] Beneficial effects: The inclination angle is determined based on the actual horizontal and vertical force ratio of the project, adapting to different load conditions and avoiding insufficient bearing capacity or material waste caused by a fixed inclination angle; the anchor rod and bearing plate are lowered and fixed as a whole, and the anchoring section is pre-embedded simultaneously, eliminating the need for secondary lowering of components and reducing in-hole installation operations. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 This is a side view of the prestressed inclined anchor foundation of the truss according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structural fit between the anchor bolt and the pressure-bearing connection structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the pressure-bearing connection structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the axial fit between the connecting device and the anchor rod in an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures: 10. Truss foundation assembly; 11. Truss foundation; 111. Horizontal bar; 112. Support truss; 12. Connecting device; 121. Outer sleeve; 122. Inner sliding sleeve; 123. Seal; 20. Anchor bolt; 21. Anchoring part; 22. Free part; 23. Connection part; 24. Tensioning part; 30. Pressure-bearing connection structure; 31. Anchor hole; 32. Pressure plate; 33. Grout structure; 34. Granular filling structure; 40. Pre-tensioning assembly; 51. Tower leg connecting plate; 52. Tower leg; 60. Rock base surface. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and 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. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] The following is combined Figures 1 to 4 The following describes embodiments of the present invention.

[0032] According to an embodiment of the present invention, in a first aspect, a truss prestressed inclined anchor foundation is provided, comprising a truss base assembly 10, anchor rods 20, a pressure-bearing connection structure 30, and a pretensioning assembly 40; the truss base assembly 10 is adapted to be connected to a tower leg; the anchor rods 20 are slidably connected to the truss base assembly 10, and multiple anchor rods 20 are inclinedly arranged along the vertical direction, the multiple anchor rods 20 being arranged axially symmetrically about the truss base assembly 10, the angle between the anchor rods 20 and the vertical direction being θ, satisfying 15°≤θ≤45°; the pressure-bearing connection structure 30 includes an anchor hole 31 and a pressure plate 32, the anchor hole 31 being adapted to be opened on a rock base surface 60, the pressure plate 32 being fixed to one end of the anchor hole 31 away from the truss base assembly 10, a portion of the anchor rod 20 being embedded in the anchor hole 31 and connected to the pressure plate 32; the pretensioning assembly 40 is connected to the other end of the anchor rod 20 to apply prestress to the anchor rod 20.

[0033] The truss prestressed inclined anchor foundation of this embodiment uses multiple anchors 20 arranged symmetrically at an angle. The inclined anchors 20 can decompose the horizontal force borne by the truss prestressed inclined anchor foundation into axial tensile force and vertical component force, so that the anchors 20 are always in an axial tensile state, preventing the truss prestressed inclined anchor foundation from undergoing large deformation in the early stage of loading. The vertical component force is borne by the truss foundation assembly 10 and the bedrock. The anchors 20 and the truss foundation assembly 10 adopt a sliding connection, eliminating the rigid connection of related technologies. The additional bending moment and shear force at the connection nodes are introduced, and the prestressing of the anchor rod 20 is no longer constrained by the truss foundation assembly 10, avoiding the risk of weak nodes that are prone to cracking and failure. The angle range between the anchor rod 20 and the vertical direction takes into account both the horizontal force distribution efficiency and the vertical anchoring bearing capacity. The lower limit of the angle ensures that the anchor rod 20 has sufficient horizontal force to resist the horizontal thrust caused by wind load and broken wire load, while the upper limit avoids that the vertical pull-out bearing capacity will be severely reduced due to the excessive inclination angle of the anchor rod 20, thus adapting to the design requirements of transmission tower foundations with different load ratios.

[0034] Specifically, in this embodiment, the material of the anchor rod 20 is selected as PSB1080 fine-rolled threaded steel bar, and the yield strength of the anchor rod 20 is 1080MPa grade, so as to be suitable for large-load tower positions and working conditions with large horizontal forces.

[0035] It should be noted that in other alternative implementations, other anchor rods 20 can be selected according to different load levels, such as PSB785 or PSB930 grade fine-rolled threaded steel bars.

[0036] Preferably, the angle θ between the anchor bolt 20 and the vertical direction satisfies 20°≤θ≤30°.

[0037] Specifically, in this embodiment, the angle θ between the anchor rod 20 and the vertical direction is 25°.

[0038] It should be noted that in other alternative embodiments, the angle between the anchor rod 20 and the vertical direction can be adjusted according to the ratio of horizontal force to vertical force. For example, when the vertical force is large, the angle between the anchor rod 20 and the vertical direction is selected as 20° to convert more horizontal force into axial force; when the horizontal force is large, the angle between the anchor rod 20 and the vertical direction is selected as 30° to balance pull-out resistance and horizontal resistance.

[0039] Specifically, in this embodiment, four anchor bolts 20 are provided (it should be noted that, in Figure 1 The image shown is a side view of the overall structure, therefore... Figure 1 The diagram shows only two anchor rods 20. The four anchor rods 20 are arranged symmetrically around the truss support assembly 10 as the center, forming an umbrella-shaped structure.

[0040] It should be noted that in other alternative implementations, the number of anchor bolts 20 can be adjusted according to the actual situation, such as six or eight.

[0041] It should be noted that the number of anchor holes 31 corresponds to the number of anchor rods 20, and multiple anchor holes 31 and multiple anchor rods 20 are in one-to-one correspondence.

[0042] Specifically, in this embodiment, the anchor rod 20 is provided with a thread at one end corresponding to the pretensioning assembly 40. The pretensioning assembly 40 tensions the anchor rod 20 upward with a through-hole jack installed on the anchor rod 20, and after reaching the designed prestress value, it tightens the tensioning nut to lock it.

[0043] Specifically, in this embodiment, the pressure plate 32 is made of Q345 steel plate, the thickness of the pressure plate 32 is 20mm, and the pressure plate 32 is threaded to the bottom of the anchor rod 20.

[0044] Of course, in other alternative embodiments, the material and thickness of the pressure plate 32 can be adjusted according to the actual situation.

[0045] It should be noted that in related technologies, large-volume concrete bases and concrete columns are often used for the construction of tower leg foundations. In this embodiment, the large-volume concrete base is replaced by a truss pier assembly 10, and the large-diameter concrete pile is replaced by an anchor rod 20, which significantly reduces the amount of concrete material used and lowers construction costs.

[0046] In one embodiment, refer to Figure 1 As shown, the truss support assembly 10 includes a truss support 11 and a connecting device 12. The truss support 11 is connected to the connecting device 12. The truss support 11 is adapted to be connected to the tower leg. The connecting device 12 is slidably connected to the anchor rod 20.

[0047] Specifically, the tower leg includes a tower leg connecting plate 51 and a tower leg 52. The tower leg connecting plate 51 is located on the top of the truss platform 11, and the tower leg 52 is connected to the side of the tower leg connecting plate 51 away from the truss platform 11.

[0048] It is worth noting that the truss base 11 is responsible for connecting with the tower leg and centrally transferring the load. Through the connecting device 12, the anchor rod 20 can slide freely relative to the truss base 11. During the prestressing process, the axial displacement of the anchor rod 20 is not constrained by the base, resulting in small prestress loss and high control accuracy.

[0049] In one embodiment, refer to Figure 4 As shown, the connecting device 12 includes an outer sleeve 121, an inner sliding sleeve 122, and a sealing element 123. The inner sliding sleeve 122 is sleeved on the anchor rod 20 and is slidably disposed inside the outer sleeve 121. The sealing element 123 is disposed between the inner sliding sleeve 122 and the outer sleeve 121.

[0050] Specifically, the outer sleeve 121 is fixed at the node of the truss foundation 11, and the inner sliding sleeve 122 is sleeved on the outside of the anchor rod 20. The anchor rod 20 and the inner sliding sleeve 122 can slide freely relative to the outer sleeve 121 along the axial direction of the anchor rod 20.

[0051] Specifically, the outer casing 121 is a steel round tube with an inner diameter of 80mm.

[0052] It is worth noting that the connecting device 12 adopts a three-layer combined sliding structure consisting of an outer sleeve 121, an inner sliding sleeve 122, and a sealing element 123. The outer sleeve 121 is rigidly fixed to the node plate of the truss foundation 11, serving as the external support base of the connecting device 12, and is stable and does not deform under stress. The inner sliding sleeve 122 is directly sleeved on the outer surface of the anchor rod 20. When the anchor rod 20 is tensioned, the upward extension and contraction of the anchor rod 20 only causes the inner sliding sleeve 122 to move relative to the outer sleeve 121. The foundation is not constrained by the tension force and will not generate additional bending moment or local crushing deformation due to prestress. After the prestress is locked, the long-term stress loss is greatly reduced. The sealing element 123 is arranged between the inner and outer sleeves 121 to avoid particle jamming and sliding failure, while isolating corrosive media from contacting the exposed rod of the anchor rod 20, thus extending the service life of the anchor rod 20.

[0053] In one embodiment, refer to Figure 4 As shown, the inner diameter of the inner sleeve 122 is D1, and the diameter of the anchor rod 20 is D2, satisfying 2mm≤D1-D2≤4mm.

[0054] Specifically, in this embodiment, the inner diameter D1 of the inner sleeve 122 is 40mm, the diameter D2 of the anchor rod 20 is 37mm, and the difference between the diameters of the inner sleeve 122 and the anchor rod 20 is 3mm.

[0055] It should be noted that, in other alternative embodiments, the difference between the diameter of the inner sliding sleeve 122 and the diameter of the anchor rod 20 can be adjusted between 2mm and 4mm according to the actual working conditions.

[0056] It should be noted that if the gap is less than 2mm, the anchor rod 20 is prone to dry friction with the inner wall of the inner sleeve 122. During the tensioning stage, the anchor rod 20 has a large resistance to expansion and contraction, resulting in deviation of the prestressing value and additional prestress loss. Long-term reciprocating sliding will also wear down the anti-corrosion protective layer of the anchor rod 20 and accelerate corrosion. If the gap is greater than 4mm, the anchor rod 20 will have a large lateral displacement within the inner sleeve 122 under horizontal load. If the displacement is too large, the rod body will squeeze the end of the inner sleeve 122 to form local concentrated stress, generating additional bending shear force.

[0057] It is worth noting that limiting the diameter difference between the inner sliding sleeve 122 and the anchor rod 20 to 2mm to 4mm ensures that there is no significant frictional resistance in the axial sliding of the anchor rod 20 during tensioning and load deformation, and that the prestressing is applied precisely and controllably. It also limits the lateral displacement of the anchor rod 20 and prevents the rod from bending under stress.

[0058] In one embodiment, refer to Figure 1As shown, the truss support 11 includes horizontal bars 111 and supporting trusses 112. The horizontal bars 111 are arranged in two layers at intervals along the vertical direction. Multiple supporting trusses 112 are arranged. The supporting trusses 112 are connected to the outer sleeve 121. One end of the supporting truss 112 is connected to one layer of horizontal bars 111, and the other end of the supporting truss 112 is connected to another layer of horizontal bars 111.

[0059] Specifically, refer to Figure 1 As shown, two layers of horizontal bars 111 are arranged vertically at intervals as shown in the figure, and the corners of the two layers of horizontal bars 111 are arranged correspondingly. The two ends of a portion of the supporting truss 112 are respectively connected to the corresponding corners of the two layers of horizontal bars 111. The supporting trusses 112 are staggered to form a triangular structure, thus improving the overall stability of the truss support platform 11.

[0060] Specifically, the supporting truss 112 of the truss platform 11 is made of steel and is fastened to the horizontal bar 111 by bolts. The steel and the horizontal bar 111 are prefabricated in the factory to facilitate rapid on-site construction.

[0061] It is worth noting that the truss platform 11 adopts a spatial combination structure of two layers of horizontal bars 111 arranged at intervals and multiple supporting trusses 112. The multiple supporting trusses 112 form a stable spatial force system between the two layers of horizontal bars 111.

[0062] In one embodiment, refer to Figure 1 As shown, the anchor rod 20 includes an anchoring part 21, a free part 22, a connecting part 23, and a tensioning part 24. The anchoring part 21, the free part 22, the connecting part 23, and the tensioning part 24 are connected in sequence. The anchoring part 21 is connected to the bearing plate 32. The anchoring part 21 and the free part 22 are embedded in the anchoring hole 31. The free part 22 is spaced apart from the hole wall of the anchoring hole 31. The connecting part 23 is slidably connected to the truss support assembly 10. The tensioning part 24 is connected to the pre-tensioning assembly 40.

[0063] It is worth noting that the anchor rod 20 is divided into four functional sections along its length: anchorage section 21, free section 22, connecting section 23, and tensioning section 24. The anchorage section 21 is embedded in the bottom of the anchorage hole 31 and rigidly connected to the bearing plate 32. During tensioning, the tension is directly transmitted to the bearing plate 32, realizing the force transmission of the pressure-type anchor rod 20. The free section 22 is spaced apart from the wall of the anchorage hole 31, leaving a buffer space so that the anchor rod 20 can produce a small lateral displacement when subjected to horizontal loads. The connecting section 23 passes through the sliding connection device 12 of the truss foundation 11, transmits axial tension, isolates bending moment and shear force, and eliminates the problem of weak connection between the foundation and the anchor rod 20. The tensioning section 24 is connected to the pre-tensioning component 40 to realize the prestressing loading of the anchor rod 20.

[0064] In one embodiment, refer to Figure 2 and Figure 3As shown, the pressure-bearing connection structure 30 also includes a grout structure 33, which is poured into the anchor hole 31. The grout structure 33, the pressure plate 32, and the anchor part 21 are connected to form a grouting anchor section.

[0065] Specifically, in this embodiment, the grout structure 33 is a high-strength grout. The grout structure 33 is poured into the bearing plate 32 through the anchoring hole 31, and the anchoring part 21 and the bearing plate 32 are bonded to the bedrock as a whole.

[0066] Specifically, the pressure plate 32 is provided with grouting holes and venting holes. When the anchor rod 20 is under tension, the pressure plate 32 converts the tension into pressure on the grout structure 33, thereby achieving pressure-type anchoring.

[0067] It is worth noting that the grout structure 33 is injected into the bottom of the anchoring hole 31. The grout, the pressure plate 32, and the anchoring part 21 of the anchor rod 20 together form the grouting anchoring section, which has high compressive strength and micro-expansion characteristics. When the pre-tensioning component 40 applies prestress to the anchor rod 20 or the tower transmits the pull-out load, the tension of the anchor rod 20 is transmitted downward to the pressure plate 32. The pressure plate 32 forms a uniform compressive stress on the grout structure 33. The grout under pressure is not prone to penetrating cracks, and it isolates the anchoring section of the anchor rod 20 from groundwater and air erosion, significantly improving the long-term anti-corrosion performance. The grout structure 33 integrally wraps the anchoring part 21 of the anchor rod 20 and the pressure plate 32, realizing uniform load transfer and no stress concentration among the anchor rod 20, the pressure plate 32, and the bedrock.

[0068] In one embodiment, refer to Figure 2 and Figure 3 As shown, the pressure-bearing connection structure 30 also includes a particle filling structure 34, which is disposed between the free part 22 and the hole wall of the anchor hole 31, and has a buffer space inside the particle filling structure 34.

[0069] Specifically, in this embodiment, a portion of sand and gravel is injected between the free portion 22 and the hole wall of the anchoring hole 31 to form a particle filling structure 34, and the small gaps between the sand and gravel form the aforementioned buffer space.

[0070] Specifically, sand and gravel are used as the granular filling structure 34, which makes it difficult for the rod body to stick to the sand and gravel, avoiding unnecessary frictional resistance and ensuring that the anchor rod 20 can produce small displacements under the action of horizontal force.

[0071] It is worth noting that a particle filling structure 34 is set between the free part 22 and the wall of the anchor hole 31, with a reserved buffer deformation space inside. The anchor rod 20 can achieve small lateral displacement, and the particles can slide relative to each other and buffer deformation, which will not generate reverse constraint shear force on the anchor rod 20 body, ensuring that all horizontal load components are transmitted only along the axial direction of the anchor rod 20.

[0072] The working principle of the truss prestressed inclined anchor foundation in this embodiment is as follows.

[0073] Regarding horizontal resistance: When the tower is subjected to horizontal forces, these forces are transmitted sequentially through the tower legs, truss foundation 11, and connecting device 12 to each anchor rod 20. Due to the inclined arrangement of the anchor rods 20, the horizontal force is decomposed into axial and vertical components on each anchor rod 20. The axial component is borne by the anchor rod 20 under axial tension, which is its optimal stress state. The vertical component is borne by the truss foundation 11.

[0074] Regarding prestressing application: After the grouting anchorage section has cured to the design strength, a through-hole jack is installed at the top tensioning section 24 of the anchor 20 to tension the anchor 20 upwards. Under tension, the bottom bearing plate 32 presses upwards against the grouting anchorage section, and the grout structure 33, under pressure, transmits the pressure to the surrounding bedrock. During tensioning, the anchor 20 experiences upward axial displacement relative to the truss foundation 11. The connecting device 12 allows the anchor 20 to slide freely, and its displacement is not constrained by the truss foundation 11. After reaching the design prestress value, the tensioning nut is tightened to lock the prestress. The prestress puts the anchor 20 in a tensile state, and the bottom bearing plate 32 converts the tension into pressure on the grout structure 33, giving the truss prestressed inclined anchor foundation an initial reaction force.

[0075] Regarding the comprehensive effect of working load: When the truss prestressed inclined anchor foundation is simultaneously subjected to uplift force and horizontal force, the uplift force is transmitted to the bedrock through the tension of the anchor 20, the compression of the grout by the bottom bearing plate 32, and the stress on the foundation. The horizontal force is decomposed into an axial component (borne by the tension of the anchor 20) and a vertical component (borne by the truss foundation 11). Prestressing results in small deformation and strong deformation recovery capacity of the foundation in the early stage of loading.

[0076] According to an embodiment of the present invention, in a second aspect, a construction method for a truss prestressed inclined anchor foundation is also provided, applicable to the construction of the aforementioned truss prestressed inclined anchor foundation, comprising the following steps: S1. Determine the angle θ between the anchor rod 20 and the vertical direction based on the ratio of the horizontal force to the vertical force borne by the truss prestressed inclined anchor rod foundation. S2. Based on the angle θ between the anchor rod 20 and the vertical direction, make anchor holes 31 on the rock base surface 60; S3. Connect the pressure plate 32 and the anchor rod 20, put the pressure plate 32 and the anchor rod 20 together into the anchor hole 31, and fix the pressure plate 32. S4. Install the truss foundation assembly 10 on the rock base surface 60, and slide the anchor rod 20 to the truss foundation assembly 10. S5. Install the pretensioning assembly 40, and pretension and fix the anchor rod 20 according to the design prestress value of the anchor rod 20.

[0077] The construction method of this embodiment determines the inclination angle based on the actual horizontal and vertical force ratio of the project, adapting to different load conditions and avoiding insufficient bearing capacity or material waste caused by a fixed inclination angle; the anchor rod 20 and the bearing plate 32 are lowered and fixed as a whole, and the pre-embedding of the anchoring section is completed simultaneously, eliminating the need for secondary lowering of components and reducing in-hole installation operations.

[0078] Specifically, in step S5, the anchor rod 20 is tensioned to the design prestress value by installing a through-hole jack, then the tensioning nut is tightened to lock the prestress, then the jack is released, and finally the tower leg is installed on the truss pier assembly 10.

[0079] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A truss prestressed inclined anchor foundation, characterized in that, include: Truss base assembly (10), the truss base assembly (10) being adapted to be connected to the tower leg; Anchor rod (20), the anchor rod (20) is slidably connected to the truss support assembly (10), and multiple anchor rods (20) are inclined along the vertical direction. The multiple anchor rods (20) are arranged symmetrically about the truss support assembly (10) as the center. The angle between the anchor rod (20) and the vertical direction is θ, which satisfies 15°≤θ≤45°. A pressure-bearing connection structure (30) includes an anchor hole (31) and a pressure plate (32). The anchor hole (31) is adapted to be opened on the rock base surface (60). The pressure plate (32) is fixed to one end of the anchor hole (31) away from the truss foundation assembly (10). A portion of the anchor rod (20) is embedded in the anchor hole (31) and connected to the pressure plate (32). A pretensioning assembly (40) is connected to the other end of the anchor rod (20) to apply prestress to the anchor rod (20).

2. The truss prestressed inclined anchor foundation according to claim 1, characterized in that, The truss support assembly (10) includes a truss support (11) and a connecting device (12). The truss support (11) is connected to the connecting device (12). The truss support (11) is adapted to be connected to the tower leg. The connecting device (12) is slidably connected to the anchor rod (20).

3. The truss prestressed inclined anchor foundation according to claim 2, characterized in that, The connecting device (12) includes an outer sleeve (121), an inner sliding sleeve (122), and a sealing element (123). The inner sliding sleeve (122) is sleeved on the anchor rod (20) and is slidably disposed inside the outer sleeve (121). The sealing element (123) is disposed between the inner sliding sleeve (122) and the outer sleeve (121).

4. The truss prestressed inclined anchor foundation according to claim 3, characterized in that, The inner diameter of the inner sleeve (122) is D1, and the diameter of the anchor rod (20) is D2, satisfying 2mm≤D1-D2≤4mm.

5. The truss prestressed inclined anchor foundation according to claim 3, characterized in that, The truss platform (11) includes horizontal bars (111) and supporting trusses (112). The horizontal bars (111) are arranged in two layers at intervals along the vertical direction. There are multiple supporting trusses (112). The supporting trusses (112) are connected to the outer tube (121). One end of the supporting truss (112) is connected to one layer of the horizontal bars (111), and the other end of the supporting truss (112) is connected to another layer of the horizontal bars (111).

6. The truss prestressed inclined anchor foundation according to any one of claims 1-4, characterized in that, The anchor rod (20) includes an anchoring part (21), a free part (22), a connecting part (23), and a tensioning part (24). The anchoring part (21), the free part (22), the connecting part (23), and the tensioning part (24) are connected in sequence. The anchoring part (21) is connected to the bearing plate (32). The anchoring part (21) and the free part (22) are embedded in the anchoring hole (31). The free part (22) is spaced apart from the hole wall of the anchoring hole (31). The connecting part (23) is slidably connected to the truss support assembly (10). The tensioning part (24) is connected to the pre-tensioning assembly (40).

7. The truss prestressed inclined anchor foundation according to claim 6, characterized in that, The pressure-bearing connection structure (30) also includes a grout structure (33), which is poured into the anchor hole (31). The grout structure (33), the pressure plate (32), and the anchor part (21) are connected to form a grouting anchor section.

8. The truss prestressed inclined anchor foundation according to claim 6, characterized in that, The pressure-bearing connection structure (30) further includes a particle filling structure (34), which is disposed between the free part (22) and the hole wall of the anchor hole (31), and has a buffer space inside the particle filling structure (34).

9. The truss prestressed inclined anchor foundation according to any one of claims 1-4, characterized in that, The angle θ between the anchor rod (20) and the vertical direction satisfies 20°≤θ≤30°.

10. A construction method for a truss prestressed inclined anchor foundation, applied to the construction of the truss prestressed inclined anchor foundation as described in any one of claims 1 to 9, characterized in that, Including the following steps: S1. Determine the angle θ between the anchor rod (20) and the vertical direction based on the ratio of the horizontal force to the vertical force borne by the prestressed inclined anchor rod foundation of the truss; S2. Based on the angle θ between the anchor rod (20) and the vertical direction, the anchor hole (31) is opened on the rock base (60). S3. Connect the pressure plate (32) and the anchor rod (20), put the pressure plate (32) and the anchor rod (20) together into the anchor hole (31), and fix the pressure plate (32); S4. Install the truss base assembly (10) on the rock base surface (60) and slide the anchor (20) to the truss base assembly (10); S5. Install the pretensioning assembly (40), and pretension and fix the anchor rod (20) according to the design prestress value of the anchor rod (20).

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