Rigid connecting device, spiral anchor single anchor foundation, overhead transmission line iron tower foundation and construction method thereof

Abstract

The invention discloses a rigid connecting device, a spiral anchor single anchor foundation, an overhead transmission line iron tower foundation and a construction method of the rigid connecting device. The rigid connecting device comprises a hoop, a connecting plate combined and fixed to the peripheral face of the hoop and a connecting rod piece. The hoop comprises two hoop profiles, and the two hoop profiles are spliced to form a hoop shape and are configured to enable the rigid connecting device to be fixedly arranged on an anchor rod of the single-screw anchor in a sleeving mode; the direction of an opening formed between the two hoop profiles is perpendicular to the center direction of the tower position; the connecting plates are combined and fixed to the outer surface of one hoop profile and comprise the first connecting plate and the second connecting plate, an angle is formed between the first connecting plate and the second connecting plate, and the center line of the included angle between the first connecting plate and the second connecting plate passes through the center of the tower position; the connecting rod piece is fixedly combined with the first connecting plate, the second connecting plate is configured to be fixedly combined with the connecting rod piece of the rigid connecting device of the adjacent spiral anchor single anchor foundation, and the displacement of the top of the spiral anchor foundation can be remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of spiral anchor foundations, and more specifically, to a rigid connection device, a spiral anchor single anchor foundation, an overhead power transmission line iron tower foundation and a construction method thereof. Background Art

[0002] In the construction of overhead transmission lines, the tower foundation is a key part to ensure the safe and stable operation of the transmission lines. Traditional tower foundations are mostly in the form of concrete step foundations, concrete pile foundations, etc. However, these traditional foundations have significant disadvantages, among which the long setting time of concrete is particularly prominent. Generally speaking, it often takes nearly a month from pouring the tower foundation to meeting the tower assembly conditions, which seriously delays the construction progress of the transmission line tower, not only increasing the construction period, but also significantly increasing the construction cost.

[0003] In recent years, the spiral anchor foundation has gradually emerged as a new type of foundation and has been widely used. The spiral anchor foundation has many advantages. It can be processed in a standardized manner in the factory, and the on-site construction is convenient and efficient. It can complete the construction of 4-5 tower foundations every day. Moreover, after the construction is completed, there is no need to wait for a long solidification time. The tower assembly and wiring work can be carried out immediately, which greatly shortens the construction period and significantly improves the construction efficiency. At the same time, the spiral anchor foundation has a simple structure and less damage to the environment. It is a new, environmentally friendly and efficient transmission line tower foundation. Summary of the invention

[0004] In view of the above problems, an object of the present invention is to provide a rigid connection device for a spiral anchor single anchor foundation, which can effectively reduce the displacement of the top of the spiral anchor foundation and improve the stability of the tower foundation.

[0005] Another object of the present invention is to provide a helical anchor single anchor foundation comprising the above rigid connection device.

[0006] Another object of the present invention is to provide an overhead power transmission line tower foundation including the above-mentioned spiral anchor single anchor foundation.

[0007] Another object of the present invention is to provide a construction method for an overhead power transmission line tower foundation.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] According to one aspect of the present invention, there is provided a method comprising:

[0010] A clamp, a connecting plate fixed to the outer peripheral surface of the clamp, and a connecting rod;

[0011] The hoop comprises two hoop profiles, which are spliced ​​to form a hoop shape and are configured to sleeve and fix the rigid connection device on the anchor rod of the single spiral anchor and are coaxially arranged with the anchor rod;

[0012] The direction of the opening formed between the two hoop profiles is perpendicular to the center direction of the tower;

[0013] The connecting plate is fixed to the outer surface of one of the hoop profiles, and the connecting plate includes a first connecting plate and a second connecting plate, the first connecting plate and the second connecting plate are arranged at an angle, and the midline of the angle between the first connecting plate and the second connecting plate passes through the center of the tower position;

[0014] The connecting rod is combined and fixed to the first connecting plate, and the second connecting plate is configured to be combined and fixed to the connecting rod of the rigid connecting device of the adjacent spiral anchor single anchor foundation.

[0015] In addition, an optional solution is that the hoop profile includes a semicircular hoop body and connecting ears located on both sides of the hoop body, the ends of the first connecting plate and the second connecting plate are combined and fixed to the outer peripheral surface of the hoop body, and the reverse extension line of the first connecting plate and the reverse extension line of the second connecting plate converge at the central axis of the hoop body;

[0016] The connecting ear is provided with a connecting hole, a bolt is connected in the connecting hole, and the axial direction of the connecting hole is perpendicular to the axial direction of the hoop body;

[0017] The connecting ears of the two clamp profiles on the same side are connected by two parallel bolts to adjust the size of the circle between the two clamp bodies, and the clamp is fixedly sleeved on the anchor rod.

[0018] In addition, an optional solution is that the inner diameter R of the hoop body is calculated by the following formula:

[0019] R=r+3mm

[0020] Wherein, r is the outer diameter of the anchor rod to which the clamp is connected.

[0021] In addition, an optional solution is that a stiffening rib is fixed between the hoop body and the connecting ear of another hoop profile;

[0022] The thickness of the hoop body and the connecting ear is the same, both of which are 8-12 mm, and the thickness of the stiffening rib is 8 mm.

[0023] In addition, an optional solution is that the rigid connection device further includes a first stiffening plate fixed between the first connection plate and the hoop, and a second stiffening plate fixed between the second connection plate and the hoop;

[0024] One end of the first stiffening plate is fixedly coupled to an end of the first connecting plate away from the hoop, and the other end is fixedly coupled to a connecting ear of the hoop profile where the connecting plate is located, close to the first connecting plate;

[0025] One end of the second stiffening plate is fixedly coupled to an end of the second connecting plate away from the hoop, and the other end is fixedly coupled to a connecting ear of the hoop profile where the connecting plate is located, close to the second connecting plate;

[0026] The thickness of the first connecting plate and the second connecting plate is the same, both of which are 10-12 mm;

[0027] The first stiffening plate and the second stiffening plate have the same thickness, both of which are 10-12 mm.

[0028] In addition, an optional solution is that the first connecting plate and the second connecting plate are both provided with a plurality of fixing holes, and the first connecting plate and the connecting rod, as well as the connecting rod of the rigid connection device of the second connecting plate and the adjacent spiral anchor single anchor foundation are connected by fixing bolts.

[0029] According to yet another aspect of the present invention, there is provided a helical anchor single anchor foundation, comprising a single helical anchor and a rigid connection device;

[0030] The rigid connection device is fixed to the anchor rod of the single helical anchor through a clamp.

[0031] In addition, an optional solution is that the angle between the first connecting plate and the central axis of the hoop and the angle between the second connecting plate and the central axis of the hoop change with the angle at which the anchor rod is screwed into the ground;

[0032] The angle between the central axis of the first connecting plate and the hoop is equal to the angle between the central axis of the anchor rod and the horizontal ground;

[0033] The angle between the central axis of the second connecting plate and the hoop is equal to the angle between the central axis of the anchor rod and the horizontal ground.

[0034] According to another aspect of the present invention, there is provided an overhead power transmission line iron tower foundation, comprising four spiral anchor single anchor foundations, the four spiral anchor single anchor foundations are arranged in a rectangular structure, and the single spiral anchors of the four spiral anchor single anchor foundations are rigidly connected by the rigid connection device;

[0035] The angle between the first connecting plate and the second connecting plate located on the same spiral anchor single anchor foundation is 90°.

[0036] According to one aspect of the present invention, there is provided a construction method for an overhead transmission line tower foundation, comprising:

[0037] Four single helical anchors are screwed into the foundation soil at a preset angle to form a quadrilateral anchor point array;

[0038] Excavating four ground trenches in the area between the four single spiral anchors, wherein the bottom surface of the ground trenches is located 0.5 m below the natural ground elevation, and the plane outlines of the four ground trenches form a rectangular structure;

[0039] A clamp is installed at a set height of each single helical anchor and is fastened to the outer peripheral surface of the single helical anchor rod by bolts, wherein the direction of the opening formed between two clamp profiles on the same single helical anchor is perpendicular to the center direction of the tower position;

[0040] The connecting rod is fixedly mounted on the first connecting plate of each rigid connecting device in the ground trench by fixing bolts, and the other end of the connecting rod is connected and fixed to the second connecting plate of the rigid connecting device on the adjacent single spiral anchor;

[0041] Backfill the trench with original soil and compact it;

[0042] When the single helical anchor is screwed into the foundation soil at an inclined angle, the extension direction of its axis points to the center of the tower position or is located on the reverse extension line of the center of the tower position.

[0043] The beneficial effects of the present invention are as follows:

[0044] In view of the technical problems existing in the prior art, the present invention provides a rigid connection device, a spiral anchor single anchor foundation, an overhead power transmission line iron tower foundation and a construction method thereof. Through the design of using softness to overcome rigidity, the traditional passive resistance to displacement is transformed into the wisdom of actively guiding the load path, which embodies the essence of "going with the flow" in modern geotechnical engineering. Through finite element analysis, the rigid connection device provided by the present invention coordinates the deformation between the single spiral anchors, so that the horizontal stiffness of the four-anchor linkage system is increased by 30-50% compared with the independent anchor rod, and the displacement of the steel cap is reduced by 20-40%. The four single spiral anchors are connected by the rigid connection device to form a closed square frame structure, which can form an anti-overturning force couple and improve the anti-overturning coefficient of the overhead power transmission line iron tower foundation by 1.2-1.5 times.

[0045] The rigid connection device connects the four single helical anchors of the overhead transmission line tower foundation into a rigid whole, effectively dispersing and transmitting the load on the tower, and significantly reducing the displacement of the top of the helical anchor foundation. When the tower is subjected to various complex loads, the rigid connection device can coordinate the joint force of each single helical anchor to avoid excessive displacement of the top steel cap due to uneven force on a single helical anchor, ensure that the stability of the tower foundation meets the requirements of the specification, and ensure the safe and stable operation of the transmission line.

[0046] The rigid connection device is connected to the single spiral anchor through a clamp and fastened with bolts. This movable connection method brings great convenience to the construction. After the single spiral anchor is constructed, the construction personnel can flexibly adjust the position of the clamp to perform the fastening operation. The operation is simple and fast, which effectively improves the construction efficiency, reduces the construction difficulty, and shortens the construction period.

[0047] The connection plate and the connecting rod are connected by fixed bolts, which makes the entire rigid connection device have good versatility. In different engineering scenarios, different specifications of connecting rods (such as different types of angle steel, steel pipes, etc.) can be flexibly selected for connection according to actual needs, meeting the connection requirements of various spiral anchor foundations and iron towers, and improving the application range of the device.

[0048] The rigid connection device is installed 0.5m below the ground ±0.00. After tightening, the trench is backfilled with the original soil. In addition to not affecting the original surface, it can also make full use of the passive resistance of the soil to form an effect similar to "invisible ground beam". The friction between the buried connecting rods and the surrounding soil makes the soil form a mechanical stop for the square frame structure formed, physically restricting the movement space of the steel cap and enhancing the anti-slip ability of the single spiral anchor. In addition, it can also play an environmental isolation role, avoiding the influence of sudden changes in surface temperature on steel deformation. When the temperature difference △T=30℃, the free expansion and contraction of 10m long steel reaches 3.6mm, which can be reduced to 0.5mm after being buried under the constraints of the land.

[0049] All steel parts of the rigid connection device are treated with hot-dip galvanizing for corrosion protection. The hot-dip galvanizing process forms a dense zinc layer on the surface of the steel parts, which effectively isolates the erosion of the steel parts by air, moisture, etc., and prevents the steel parts from being corroded during long-term use. It greatly extends the service life of the rigid connection device, makes it meet the safety life requirements of the project, reduces the subsequent maintenance costs, and improves the reliability and stability of the entire transmission line tower foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0051] Figure 1 The schematic diagram of the structure of a single helical anchor in the prior art is shown.

[0052] Figure 2 The figure shows the layout of the overhead transmission line tower foundation in the prior art.

[0053] Figure 3 A schematic diagram showing a conventional single helical anchor being screwed into soil.

[0054] Figure 4 A side view of a rigid connection device provided by an embodiment of the present invention is shown.

[0055] Figure 5 A top view of a rigid connection device provided by an embodiment of the present invention is shown.

[0056] Figure 6 A schematic structural diagram of a first connecting plate provided in an embodiment of the present invention is shown.

[0057] Figure 7 An assembly diagram showing a rigid connection device provided by an embodiment of the present invention realizing a rigid connection between spiral anchor and single anchor foundations at 0.5 m below ±0.00 underground.

[0058] Figure 8 A structural schematic diagram of a spiral anchor single anchor foundation provided by an embodiment of the present invention is shown.

[0059] Fig. 9 The following diagram shows the arrangement of the overhead power transmission line tower foundation provided by the novel embodiment of the present invention when a single spiral anchor is vertically screwed in.

[0060] Fig.10 The layout diagram of the overhead transmission line tower foundation provided by the new embodiment of the present invention when the single screw anchor is tilted and screwed in is shown. DETAILED DESCRIPTION

[0061] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0062] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] In the present invention, unless otherwise clearly stipulated and limited, a first feature being “on” or “under” a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through another feature between them.

[0064] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplified operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0065] Conventional overhead transmission line tower spiral anchor single anchor foundation single spiral anchor 1 such as Figure 1 As shown, it includes an anchor rod 11, an anchor plate 12, an anchor head 13 and a steel cap 14. The anchor rod 11 is made of a straight seam welded pipe or a seamless steel pipe, and the anchor plate 12 is made of a steel plate, which are pressed and processed by special equipment. The anchor rod 11 and the anchor plate 12 are assembled according to the requirements of the drawings and then welded. According to the force applied to the tower and the geological conditions on site, and according to the size of the foundation root opening, the base anchor of the single spiral anchor is screwed into the soil vertically or at a certain angle, and then a steel cap 14 is set at the top of the base anchor and connected to the tower foot of the tower with bolts to complete the assembly of the tower and the spiral anchor foundation.

[0066] The foundation of an overhead transmission line tower is generally composed of four single-anchor screw anchor foundations, usually arranged in a square or rectangular cross-section, such as Figure 2 shown.

[0067] However, in practical applications, conventional helical anchor single anchor foundations have exposed a serious problem. Whether it is a single helical anchor rod (such as Figure 3 As shown in Figure a), or the case of tilted screw-in (as shown in Figure a) Figure 3 As shown in Figure b), when the tower is subjected to various loads, the steel cap 14 at the top of the anchor rod 11 is prone to excessive displacement. This displacement sometimes exceeds the requirements of relevant specifications, which not only affects the stability of the tower foundation, but also may cause safety hazards such as tower tilt and line failure, greatly limiting the wide application of spiral anchor single anchor foundation in actual engineering.

[0068] As a key force transmission component in the foundation of overhead transmission line tower, steel cap is used to connect the tower legs and the screw anchor foundation, and plays an important role in transferring the tower load (vertical pressure, horizontal force, bending moment, etc.) to the foundation. The mechanical essence of steel cap displacement is actually the imbalance between external load and foundation reaction force. Since the test of the Electric Power Research Institute (EPRI) of the United States shows that the horizontal stiffness of the four-anchor linkage system is only 15% higher than that of independent anchor rods, it is generally recognized that the synergy effect between single screw anchors is limited. Therefore, the existing technology mainly focuses on the bearing capacity and pull-out resistance of single anchors in the corresponding steel cap displacement problem, and rarely considers the optimization of the overall synergy effect of the overhead transmission line tower foundation.

[0069] In view of the defects of the prior art, the present invention provides a rigid connection device 2 for realizing a rigid connection between spiral anchor and single anchor foundations. The device is located 0.5m below the ground ±0.00. After four single spiral anchors 1 are screwed into the soil, trenches are excavated between the single spiral anchors 1, and then the rigid connection device 2 is fastened between the four single spiral anchors 1 to form a rigid connection. Finally, the original soil is backfilled to complete the construction.

[0070] Combination Figure 4-7 As shown, the rigid connection device includes a hoop 21 , a connecting plate fixed to the outer peripheral surface of the hoop 21 , and a connecting rod 22 .

[0071] The hoop 21 includes two hoop profiles, which are spliced ​​to form a hoop shape and are configured to sleeve the rigid connection device 2 on the anchor rod 11 of the single spiral anchor 1 and be coaxially arranged with the anchor rod 11 .

[0072] The direction of the opening 210 formed between the two hoop profiles is perpendicular to the center direction of the tower.

[0073] The connecting plate is fixed to the outer surface of one of the hoop profiles, and the hoop profile faces the space enclosed by the multiple single spiral anchors 1. The connecting plate includes a first connecting plate 23 and a second connecting plate 24, and the first connecting plate 23 and the second connecting plate 24 are arranged at an angle, and the midline of the angle α between the first connecting plate 23 and the second connecting plate 24 ( Figure 5 The midpoint line) passes through the center O of the tower.

[0074] The connecting rod 22 is combined and fixed to the first connecting plate 23, and the second connecting plate 24 is configured to be combined and fixed with the connecting rod 22 of the rigid connection device 2 of the adjacent spiral anchor single anchor foundation, so that multiple spiral anchor single anchor foundations constituting the foundation of the overhead transmission line tower can be connected end to end for rigid connection.

[0075] In a specific embodiment, Figure 5 As shown, the hoop profile includes a semicircular hoop body 211 and connecting ears 212 located on both sides of the hoop body 211. The hoop profile is made of steel plates folded and welded, and the material is Q235B or Q355B.

[0076] In this embodiment, ends of the first connecting plate 23 and the second connecting plate 24 are welded and fixed to the outer circumference of the hoop body 211 , and the reverse extension lines of the first connecting plate 23 and the second connecting plate 24 converge at the central axis of the hoop body 211 .

[0077] In a specific example, the first connecting plate 23 and the second connecting plate 24 are symmetrically arranged, and the shapes and thicknesses of the two are the same. For example, the thicknesses of the first connecting plate 23 and the second connecting plate 24 are both 10-12 mm. The appropriate thickness design enables the connecting plate to have sufficient bearing capacity when connecting the connecting rods, and can stably transmit the forces between the components, ensuring a firm connection, and further enhancing the overall performance of the rigid connection device 2.

[0078] The connecting ear 212 is provided with a connecting hole, in which a bolt 3 is connected, and the axial direction of the connecting hole is perpendicular to the axial direction of the hoop body 211. Figure 5 As shown, two connecting ears 212 of two hoop profiles on the same side are connected by two parallel bolts 3 to adjust the size of the ring between the two hoop bodies 211, and the hoop 21 is fixedly sleeved on the corresponding anchor rod 11. During construction, by tightening the bolts 3, the hoop 21 tightly holds the anchor rod 11, ensuring that the connection between the hoop 21 and the anchor rod 11 is tight and reliable, and the load can be effectively transmitted, ensuring that the entire rigid connection device 2 can work stably.

[0079] In a specific embodiment, the inner diameter R of the hoop body 211 is calculated by the following formula:

[0080] R=r+3mm

[0081] Wherein, r is the outer diameter of the anchor rod 11 connected to the clamp 21.

[0082] Such an inner diameter design not only facilitates the fastening connection of the clamp 21 to the anchor rod 11 after the construction of the anchor rod 11 is completed, but also ensures that there is a suitable clamping force between the clamp 21 and the anchor rod 11, thereby preventing the clamp 21 from shaking or falling off on the anchor rod 11, and can effectively enhance the stability of the connection between the rigid connection device 2 and the single spiral anchor 1, thereby ensuring that under various working conditions, the clamp 21 can firmly clamp the anchor rod 11 and reduce the risk of displacement.

[0083] In a specific embodiment, the hoop profile is made of folded and welded steel plates, that is, the hoop body 211 and the connecting ear 212 have the same thickness. In this embodiment, the hoop body 211 and the connecting ear 212 are both 8-12 mm thick, which can ensure the strength of the hoop 21 while taking into account the material cost and processing difficulty, ensuring that the hoop 21 is not easily deformed or damaged when subjected to external force, thereby ensuring the reliability of the entire rigid connection device 2.

[0084] In a specific embodiment, Figure 4-5As shown, a stiffening rib 213 is fixed between the hoop body 211 and the connecting ear 212 of a hoop profile without a mounting plate. The stiffening rib 213 has a plate thickness of 8 mm and plays a reinforcing role. It can enhance the structural strength of the hoop profile, so that the hoop 21 can maintain good structural integrity when clamping the anchor rod 11 and bearing external forces, reduce the risk of local deformation of the hoop 21, and further improve the stability of the rigid connection device 2.

[0085] In a specific embodiment, Figure 4-5 As shown, the rigid connection device 2 further includes a first stiffening plate 25 fixed between the first connection plate 23 and the hoop 21 , and a second stiffening plate 26 fixed between the second connection plate 24 and the hoop 21 .

[0086] In this embodiment, one end of the first stiffening plate 25 is fixedly combined with one end of the first connecting plate 23 away from the hoop 21, and the other end is fixedly combined with the connecting ear 212 of the hoop profile where the connecting plate is located close to the first connecting plate 23, forming a triangular stable structure. The thickness of the first stiffening plate 25 is 10-12mm. The main function of the first stiffening plate 25 is to strengthen the first connecting plate 23. In the actual force-bearing process, it can effectively improve the deformation resistance of the first connecting plate 23 and prevent the first connecting plate 23 from bending or breaking when it is subjected to a large load, thereby ensuring the reliability and stability of the entire rigid connection device 2 and extending the service life of the rigid connection device 2.

[0087] Correspondingly, one end of the second stiffening plate 26 is fixedly combined with one end of the second connecting plate 24 away from the hoop 21, and the other end is fixedly combined with the connecting ear 212 of the hoop profile where the connecting plate is located close to the second connecting plate 24, forming a triangular stable structure. The thickness of the second stiffening plate 26 is 10-12mm. The main function of the second stiffening plate 26 is to strengthen the second connecting plate 24. In the actual force-bearing process, it can effectively improve the deformation resistance of the second connecting plate 24 and prevent the second connecting plate 24 from bending or breaking when subjected to a large load, thereby ensuring the reliability and stability of the entire rigid connection device 2 and extending the service life of the rigid connection device 2.

[0088] In a specific embodiment, Figure 6 As shown, a plurality of fixing holes 20 are provided on the first connecting plate 23 and the second connecting plate 24. Figure 5 As shown, the first connecting plate 23 and the connecting rod 22, as well as the second connecting plate 24 and the connecting rod 22 of the rigid connection device of the adjacent spiral anchor single anchor foundation are connected by fixing bolts 4, so that multiple spiral anchor single anchor foundations constituting the foundation of the overhead transmission line tower can be connected end to end for rigid connection.

[0089] In a specific embodiment, in order to ensure the structural strength of the rigid connection device 2, the connection rod 22 is preferably a steel pipe or round steel.

[0090] In one embodiment, the clamp 21, the connecting plate, the connecting rod 22, the stiffening rib 213, the first stiffening plate 25 and the second stiffening plate 26 are all made of hot-dip galvanized steel. The hot-dip galvanizing process can form a dense zinc layer on the surface of the steel part, effectively preventing the steel part from being corroded during long-term use, extending the service life of the rigid connection device 2, making it meet the safety life requirements of the project, reducing the later maintenance cost, and improving the reliability and stability of the entire transmission line tower foundation.

[0091] Another embodiment of the present invention provides a spiral anchor single anchor foundation, combined with Figure 8 As shown, the spiral anchor single anchor foundation comprises a single spiral anchor 1 and a rigid connection device 2 provided in the above embodiment. The rigid connection device 2 is fixed to the anchor rod 11 of the single spiral anchor 1 through a clamp 21 and is located near the top of the anchor rod 11.

[0092] During construction, the single helical anchor 1 includes two screwing modes: vertical screwing and inclined screwing. Figure 8 Figure a is a schematic diagram of the structure of a vertically screwed single helical anchor 1 equipped with a rigid connection device 2, and Figure b is a schematic diagram of the structure of a tilted screwed single helical anchor 1 equipped with a rigid connection device 2. Figure 8 It can be seen that, no matter the single helical anchor 1 is screwed in vertically or in an inclined manner, the first connecting plate 23 and the second connecting plate 24 of the corresponding rigid connecting device 2 are both arranged perpendicular to the horizontal ground.

[0093] In a specific embodiment, the angle β between the first connecting plate 23 and the central axis of the hoop 21 changes with the angle at which the anchor rod 11 is screwed into the ground. Specifically, the angle β between the first connecting plate 23 and the central axis of the hoop 21 is equal to the angle γ between the central axis of the anchor rod 11 and the horizontal ground. When the single helical anchor 1 is screwed in vertically, the first connecting plate 23 is welded and fixed to the outer peripheral surface of the hoop 21 along the radial direction of the hoop 21.

[0094] The second connecting plate 24 is similar. Specifically, the angle between the second connecting plate 24 and the central axis of the hoop 21 changes as the angle of the anchor rod 11 screwed into the ground. Specifically, the angle between the second connecting plate 24 and the central axis of the hoop 21 is equal to the angle γ between the central axis of the anchor rod 11 and the horizontal ground. When the single helical anchor 1 is screwed in vertically, the second connecting plate 24 is welded and fixed to the outer peripheral surface of the hoop 21 along the radial direction of the hoop 21.

[0095] Another embodiment of the present invention provides an overhead transmission line tower foundation, such as Figure 9-10As shown, it includes four spiral anchor single anchor foundations 100 provided by the above embodiments, and the four spiral anchor single anchor foundations 100 are arranged in a square structure or a matrix structure, and the single spiral anchors 1 of the four spiral anchor single anchor foundations 100 are rigidly connected by a rigid connection device 2. The angle between the first connecting plate 23 and the second connecting plate 24 located in the same spiral anchor single anchor foundation 100 is 90°. It should be noted that the angle between the first connecting plate 23 and the second connecting plate 24 located in the same spiral anchor single anchor foundation 100 is affected by the number and arrangement structure of the spiral anchor single anchor foundation 100, and can be adjusted according to actual conditions.

[0096] The overall connection method of the foundation of the overhead transmission line tower is as follows: during the foundation construction, after four single spiral anchors 1 are screwed into the soil, a trench is first excavated between the single spiral anchors 1 at 0.5m below ±0.00 on the ground, and the trench is square or rectangular after excavation. The clamp 21 is installed on the single spiral anchor 1, and the direction of the opening formed between the two clamp profiles is perpendicular to the center direction of the tower. After the clamp 21 is tightened with bolts 3, a connecting rod 22 (such as a steel pipe or round steel) is installed on the connecting plate of the clamp 21, so that the single spiral anchor 1, the clamp 21, the connecting plate and the connecting rod 22 form an integral rigid connection device, and after the installation and tightening of the connection device are completed, the trench is backfilled with the original soil. It should be noted that when the single spiral anchor 1 is screwed in at an angle, its tilting direction should point to the center of the tower or be located on the reverse extension line of the center of the tower.

[0097] Another embodiment of the present invention provides a construction method for the above-mentioned overhead transmission line tower foundation, which specifically includes the following steps:

[0098] Step 1: screw four single helical anchors 1 into the foundation soil at a preset angle to form a quadrilateral anchor point array;

[0099] Step 2: excavating four trenches in the area between the four single spiral anchors 2, wherein the bottom surface of the trenches is located 0.5 m below the natural ground elevation, and the plane contours of the four trenches form a rectangular structure;

[0100] Step 3: Install a clamp 21 at a set height of each single spiral anchor 1 and fasten the clamp 21 to the outer peripheral surface of the anchor rod 11 of the single spiral anchor 1 by means of bolts 3, wherein the direction of the opening 20 formed between two clamp profiles on the same single spiral anchor 1 is perpendicular to the center direction of the tower position;

[0101] The connecting rod 22 is fixedly installed on the first connecting plate 23 of each rigid connecting device 2 in the ground trench by means of fixing bolts 4, and the other end of the connecting rod 22 is connected and fixed to the second connecting plate 24 of the rigid connecting device 2 on the adjacent single helical anchor 1;

[0102] Backfill the trench with original soil and compact it.

[0103] When the single helical anchor 1 is screwed into the foundation soil at an inclined angle, the extension direction of its axis points to the center of the tower or is located on the reverse extension line of the center of the tower. When the single helical anchor screwed in at an inclined angle points to the center of the tower O, its axis forms a collinear or small angle relationship with the force transmission direction of the tower leg, so that the horizontal load (such as wind load) is converted into axial tension through the inclined angle of the anchor rod, reducing the bending moment component and improving the pull-out resistance efficiency.

[0104] In the construction method of the overhead transmission line tower foundation provided by the embodiment of the present invention, four single spiral anchors are connected by a rigid connection device to form a closed square frame structure, and the originally independent anchor fixing points are integrated into a spatial steel frame structure, which can achieve uniform distribution of loads and avoid single-point stress concentration. It can resist horizontal torque and eccentric loads through the overall geometric stability, and utilize the axial stiffness and bending resistance of the connecting rods to convert local deformation into coordinated deformation of the overall structure.

[0105] In addition, by connecting four single helical anchors through a rigid connecting device, a truss effect can be formed, and each single helical anchor can be laterally constrained to limit the lateral displacement of the top of the anchor rod. Through the design of this embodiment, 80% of the horizontal load is converted into the axial force of the closed direction frame structure formed. Instead of relying solely on the shear resistance of the steel cap to offset the horizontal load as in the prior art, the displacement of the steel cap can be avoided, and the bending moment generated by the asymmetric load can be internally offset, thereby avoiding cumulative plastic deformation at the connection point between the anchor rod and the steel cap, thereby avoiding undesirable displacement of the steel cap.

[0106] Since the rigid connection device is located 0.5m below the ground ±0.00 and needs to be backfilled with original soil after installation, the passive resistance of the soil can be fully utilized to form an effect similar to an "invisible ground beam". The friction between the buried connecting rods and the surrounding soil makes the soil form a mechanical stop for the square frame structure formed, physically limiting the movement space of the steel cap and enhancing the anti-slip ability of the single spiral anchor. In addition, it can also play an environmental isolation role, avoiding the influence of sudden changes in surface temperature on steel deformation. When the temperature difference △T = 30℃, the free expansion and contraction of 10m long steel reaches 3.6mm, which can be reduced to 0.5mm after being buried under the constraints of the land.

[0107] The rigid connection device, spiral anchor single anchor foundation, overhead power transmission line iron tower foundation and construction method provided by the embodiment of the present invention, through the design of overcoming rigidity with softness, transform the traditional passive resistance to displacement into the wisdom of actively guiding the load path, reflecting the essence of "going with the flow" in modern geotechnical engineering. Through finite element analysis, the rigid connection device provided by the present invention coordinates the deformation between the single spiral anchors, so that the horizontal stiffness of the four-anchor linkage system is increased by 30-50% compared with the independent anchor rod, and the displacement of the steel cap is reduced by 20-40%. The four single spiral anchors are connected by the rigid connection device to form a closed square frame structure, which can form an anti-overturning force couple and increase the anti-overturning coefficient of the overhead power transmission line iron tower foundation by 1.2-1.5 times.

[0108] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A rigid connection device for rigid connection between spiral anchor single anchor foundations, characterized in that: include: A clamp, a connecting plate fixed to the outer peripheral surface of the clamp, and a connecting rod; The hoop comprises two hoop profiles, which are spliced ​​to form a hoop shape and are configured to sleeve and fix the rigid connection device on the anchor rod of the single spiral anchor and are coaxially arranged with the anchor rod; The direction of the opening formed between the two hoop profiles is perpendicular to the center direction of the tower; The connecting plate is fixed to the outer surface of one of the hoop profiles, and the connecting plate includes a first connecting plate and a second connecting plate, the first connecting plate and the second connecting plate are arranged at an angle, and the midline of the angle between the first connecting plate and the second connecting plate passes through the center of the tower position; The connecting rod is combined and fixed to the first connecting plate, and the second connecting plate is configured to be combined and fixed to the connecting rod of the rigid connecting device of the adjacent spiral anchor single anchor foundation.

2. The rigid connection device according to claim 1, characterized in that: The hoop profile includes a semicircular hoop body and connecting ears located on both sides of the hoop body, the ends of the first connecting plate and the second connecting plate are fixedly connected to the outer peripheral surface of the hoop body, and the reverse extension line of the first connecting plate and the reverse extension line of the second connecting plate converge at the central axis of the hoop body; The connecting ear is provided with a connecting hole, a bolt is connected in the connecting hole, and the axial direction of the connecting hole is perpendicular to the axial direction of the hoop body; The connecting ears of the two clamp profiles on the same side are connected by two parallel bolts to adjust the size of the circle between the two clamp bodies, and the clamp is fixedly sleeved on the anchor rod.

3. The rigid connection device according to claim 2, characterized in that: The inner diameter R of the hoop body is calculated by the following formula: R=r+3mm Wherein, r is the outer diameter of the anchor rod to which the clamp is connected.

4. The rigid connection device according to claim 2, characterized in that: A stiffening rib is fixed between the hoop body and the connecting ear of another hoop profile; The thickness of the hoop body and the connecting ear is the same, both of which are 8-12 mm, and the thickness of the stiffening rib is 8 mm.

5. The rigid connection device according to claim 2, characterized in that: The rigid connection device further comprises a first stiffening plate fixed between the first connection plate and the hoop, and a second stiffening plate fixed between the second connection plate and the hoop; One end of the first stiffening plate is fixedly coupled to an end of the first connecting plate away from the hoop, and the other end is fixedly coupled to a connecting ear of the hoop profile where the connecting plate is located, close to the first connecting plate; One end of the second stiffening plate is fixedly coupled to an end of the second connecting plate away from the hoop, and the other end is fixedly coupled to a connecting ear of the hoop profile where the connecting plate is located, close to the second connecting plate; The thickness of the first connecting plate and the second connecting plate is the same, both of which are 10-12 mm; The first stiffening plate and the second stiffening plate have the same thickness, both of which are 10-12 mm.

6. The rigid connection device according to claim 1, characterized in that: The first connecting plate and the second connecting plate are both provided with a plurality of fixing holes, and the first connecting plate and the connecting rod, as well as the connecting rod of the rigid connecting device of the second connecting plate and the adjacent spiral anchor single anchor foundation are connected by fixing bolts.

7. A spiral anchor single anchor foundation, characterized in that: comprising a single helical anchor and a rigid connection device as claimed in any one of claims 1 to 6; The rigid connection device is fixed to the anchor rod of the single helical anchor through a clamp.

8. The spiral anchor single anchor foundation according to claim 7, characterized in that: The angle between the first connecting plate and the central axis of the hoop and the angle between the second connecting plate and the central axis of the hoop change as the angle at which the anchor rod is screwed into the ground; The angle between the central axis of the first connecting plate and the hoop is equal to the angle between the central axis of the anchor rod and the horizontal ground; The angle between the central axis of the second connecting plate and the hoop is equal to the angle between the central axis of the anchor rod and the horizontal ground.

9. An overhead power transmission line tower foundation, characterized in that: It comprises four spiral anchor single anchor foundations as claimed in any one of claims 7 to 8, wherein the four spiral anchor single anchor foundations are arranged in a rectangular structure, and the single spiral anchors of the four spiral anchor single anchor foundations are rigidly connected by the rigid connection device; The angle between the first connecting plate and the second connecting plate located on the same spiral anchor single anchor foundation is 90°.

10. A construction method for an overhead power transmission line tower foundation according to claim 9, characterized in that: include: Four single helical anchors are screwed into the foundation soil at a preset angle to form a quadrilateral anchor point array; Excavating four ground trenches in the area between the four single spiral anchors, wherein the bottom surface of the ground trenches is located 0.5 m below the natural ground elevation, and the plane outlines of the four ground trenches form a rectangular structure; A clamp is installed at a set height of each single helical anchor and is fastened to the outer peripheral surface of the single helical anchor rod by bolts, wherein the direction of the opening formed between two clamp profiles on the same single helical anchor is perpendicular to the center direction of the tower position; The connecting rod is fixedly mounted on the first connecting plate of each rigid connecting device in the ground trench by fixing bolts, and the other end of the connecting rod is connected and fixed to the second connecting plate of the rigid connecting device on the adjacent single spiral anchor; Backfill the trench with original soil and compact it; When the single helical anchor is screwed into the foundation soil at an inclined angle, the extension direction of its axis points to the center of the tower position or is located on the reverse extension line of the center of the tower position.

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