CN119860014A - Rigid connection device, spiral anchor single-anchor foundation, overhead transmission line iron tower foundation and construction method of overhead transmission line iron tower foundation - Google Patents

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 thereof, wherein the rigid connecting device comprises a hoop, a connecting plate combined and fixed on the outer peripheral surface of the hoop, and a connecting rod piece; the anchor ear comprises two anchor ear sectional materials which are spliced to form an anchor ear shape and are configured to sleeve and fix the rigid connecting device on an anchor rod of a single screw anchor, the direction of an opening formed between the two anchor ear sectional materials is perpendicular to the central direction of a tower position, the connecting plate is combined and fixed on the outer surface of one anchor ear sectional material, the connecting plate comprises a first connecting plate and a second connecting plate, the first connecting plate and the second connecting plate are arranged at an angle, the central line of the included angle between the first connecting plate and the second connecting plate passes through the central of the tower position, the connecting rod is combined and fixed on the first connecting plate, and the second connecting plate is combined and fixed with the connecting rod of the rigid connecting device of the adjacent single screw anchor foundation, so that the top displacement of the screw anchor foundation can be remarkably reduced.

Description

Rigid connection device, spiral anchor single-anchor foundation, overhead transmission line iron tower foundation and construction method of overhead transmission line iron tower foundation

Technical Field

The invention relates to the technical field of screw anchor foundations. More particularly, it relates to a rigid connection device, a screw anchor single anchor foundation, an overhead transmission line iron tower foundation and a construction method thereof.

Background

In overhead transmission line construction, the iron tower foundation is a key part for ensuring safe and stable operation of the transmission line. The traditional iron tower foundation mostly adopts forms such as concrete step foundation, concrete pile foundation. However, these conventional foundations have significant drawbacks, particularly with respect to the long setting time of the concrete. Under the general condition, the iron tower foundation often needs a period of about one month from pouring to meeting the iron tower assembly condition, which seriously delays the construction progress of the transmission line tower, not only increases the engineering construction period, but also greatly increases the construction cost.

In recent years, screw anchor foundations have come up as a new form of foundation and are widely used. The screw anchor foundation has many advantages, can carry out standardized processing in the mill, and site operation is convenient high-efficient, can accomplish the construction of 4-5 basic iron tower foundations every day. And the long solidification time is not needed to wait after the construction is finished, the iron tower assembly and the wire erection work can be immediately carried out, the construction period is greatly shortened, and the construction efficiency is remarkably improved. Meanwhile, the spiral anchor foundation is simple in structure, less in damage to the environment and is a novel, environment-friendly and efficient power transmission line iron tower foundation.

Disclosure of Invention

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

It is another object of the present invention to provide a screw anchor mono-anchor foundation comprising the above rigid connection means.

Still another object of the present invention is to provide an overhead transmission line pylon foundation comprising the above-described screw anchor single anchor foundation.

The invention further aims to provide a construction method of the overhead transmission line iron tower foundation.

In order to achieve the above purpose, the invention adopts the following technical scheme:

according to one aspect of the present invention, there is provided a method comprising:

The anchor ear is combined and fixed with a connecting plate on the outer peripheral surface of the anchor ear and a connecting rod piece;

the anchor ear comprises two anchor ear sectional materials which are spliced to form an anchor ear shape and are configured to be sleeved and fixed on an anchor rod of a single-screw anchor and coaxially arranged with the anchor rod;

the direction of an opening formed between the two hoop sections is perpendicular to the central direction of the tower;

The connecting plates are combined and fixed on the outer surface of one of the hoop sectional materials, the connecting plates comprise 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 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 is fixedly combined with the first connecting plate, and the second connecting plate is fixedly combined with the connecting rod of the rigid connecting device of the adjacent spiral anchor single-anchor foundation.

In addition, the alternative scheme is that the hoop section comprises a semicircular hoop body and connecting lugs positioned at two sides of the hoop body, the ends of the first connecting plate and the second connecting plate are combined and fixed on the peripheral surface of the hoop body, and the reverse extension lines of the first connecting plate and the second connecting plate converge on the central axis of the hoop body;

The connecting lugs are provided with connecting holes, bolts are connected in the connecting holes, and the axial direction of the connecting holes is perpendicular to the axial direction of the hoop body;

the two anchor ear profiles are connected through the two parallel bolts and are positioned on the same side of the connecting lugs, so that the size of a loop opening between the two anchor ear bodies is adjusted, and the anchor ear is fixedly sleeved on the anchor rod.

Furthermore, alternatively, the inner diameter R of the hoop body is calculated by the following formula:

R=r+3mm

And r is the outer diameter of the anchor rod connected with the anchor hoop.

In addition, the alternative proposal is that a stiffening rib is fixed between the hoop body and the connecting lug of the other hoop section bar;

The thickness of the hoop body is 8-12mm, and the thickness of the stiffening rib is 8mm.

In addition, optionally, the rigid connection device further comprises a first stiffening plate fixed between the first connection plate and the anchor ear, and a second stiffening plate fixed between the second connection plate and the anchor ear;

One end of the first stiffening plate is combined and fixed with one end of the first connecting plate far away from the anchor ear, and the other end of the first stiffening plate is combined and fixed with the connecting ear, close to the first connecting plate, of the anchor ear section bar where the connecting plate is located;

One end of the second stiffening plate is combined and fixed with one end of the second connecting plate far away from the anchor ear, and the other end of the second stiffening plate is combined and fixed with the connecting lug, close to the second connecting plate, of the anchor ear profile where the connecting plate is located;

the thickness of the first connecting plate is 10-12mm, and the thickness of the second connecting plate is the same;

the thickness of the first stiffening plate is 10-12mm, and the thickness of the second stiffening plate is the same.

In addition, the alternative scheme is that a plurality of fixing holes are formed in the first connecting plate and the second connecting plate, the first connecting plate and the connecting rod piece are connected through fixing bolts, and the second connecting plate and the connecting rod piece of the rigid connecting device of the adjacent spiral anchor single-anchor foundation are connected.

According to yet another aspect of the present invention, there is provided a screw anchor single anchor foundation comprising a single screw anchor and a rigid connection means;

the rigid connecting device is fixed on the anchor rod of the single-screw anchor through anchor ear combination.

Furthermore, alternatively, the angle between the central axes of the first connecting plate and the anchor ear and the angle between the central axes of the second connecting plate and the anchor ear are changed along with the angle of screwing the anchor rod into the ground;

the angle between the first connecting plate and the central axis of the anchor ear is equal to the angle between the central axis of the anchor rod and the horizontal ground;

The angle between the central axis of second connecting plate and staple bolt equals the angle between the central axis of stock and the level ground.

According to still another aspect of the present invention, there is provided an overhead transmission line iron tower foundation, including four screw anchor single anchor foundations, the four screw anchor single anchor foundations being arranged in a rectangular structure, the single screw anchors of the four screw anchor single anchor foundations being rigidly connected by the rigid connection device;

the angle between the first connecting plate and the second connecting plate of the single anchor foundation of the same spiral anchor is 90 degrees.

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

screwing the four single-screw anchors into the foundation soil body at a preset angle to form a quadrilateral anchor point array;

Digging four trench grooves in the area between the four single screw anchors, wherein the bottom surface of the trench groove is 0.5m below the natural ground elevation, and the plane outlines of the four trench grooves are enclosed to form a rectangular structure;

Installing anchor bolts at the set height of each single-screw anchor and fastening the anchor bolts on the outer peripheral surface of the single-screw anchor rod through bolts, wherein the direction of an opening formed between two anchor bolt sectional materials positioned on the same single-screw anchor is perpendicular to the central direction of the tower;

Fixedly mounting a connecting rod piece on a first connecting plate of each rigid connecting device through a fixing bolt in a trench, and connecting and fixing the other end of the connecting rod piece with a second connecting plate of the rigid connecting device on an adjacent single-screw anchor;

backfilling the land groove with undisturbed soil and compacting;

When the single screw anchor is screwed into the foundation soil body at an inclined angle, the axis extending direction of the single screw anchor points to the center of the tower or is positioned on the reverse extension line of the center of the tower.

The beneficial effects of the invention are as follows:

Aiming at the technical problems in the prior art, the invention provides the rigid connecting device, the spiral anchor single-anchor foundation, the overhead transmission line iron tower foundation and the construction method thereof, and the design of the flexible steel is used for converting the traditional passive displacement resistance thought into the wisdom of actively guiding a load path, so that the gist of 'homeotropic' of modern geotechnical engineering is embodied. Through finite element analysis, the rigid connecting device provided by the invention coordinates deformation among the single screw anchors, so that the horizontal rigidity of a four-anchor linkage system is improved by 30-50% compared with that of an independent anchor rod, the displacement of a steel bearing platform is reduced by 20-40%, the four single screw anchors are connected through the rigid connecting device to form a closed square frame structure, an anti-overturning couple can be formed, and the anti-overturning coefficient of an overhead transmission line iron tower foundation is improved by 1.2-1.5 times.

The rigid connecting device connects four single screw anchors of the overhead transmission line iron tower foundation into a rigid whole, effectively disperses and transmits the load born by the tower, and obviously reduces the top displacement of the screw anchor foundation. When the tower bears various complex loads, the rigid connection device can coordinate the common stress of each single screw anchor, avoid the overlarge displacement of the top steel bearing platform caused by uneven stress of the single screw anchor, ensure the stability of the foundation of the iron tower to meet the standard requirement, and ensure the safe and stable operation of the power transmission line.

The rigid connecting device is connected with the single-screw anchor through the anchor ear and fastened by the bolt, and the movable connecting mode brings great convenience for construction. After the single spiral anchor is constructed, constructors can flexibly adjust the position of the anchor ear to fasten, the operation is simple and quick, the construction efficiency is effectively improved, the construction difficulty is reduced, and the engineering construction period is shortened.

The connecting plate and the connecting rod piece are connected by adopting a fixing bolt, so that the whole rigid connecting device has good universality. In different engineering scenes, can be according to actual demand, connect member (such as angle steel, the steel pipe etc. of different models) of nimble selection different specifications and connect, satisfy the connection demand of multiple screw anchor basis and iron tower, improved the application scope of device.

The rigid connection device is arranged at the position of 0.5m below the ground plus or minus 0.00, after the fastening is finished, the original soil is used for backfilling the trench, the original ground surface is not influenced, the passive resistance of the soil can be fully utilized, the effect similar to an invisible ground beam is formed, the friction between the connection rod piece buried underground and the surrounding soil body enables the soil body to form a mechanical stop for the formed square frame structure, the movement space of the steel bearing platform is physically limited, and the anti-sliding capacity of the single-screw anchor is enhanced. In addition, the method has the advantages of having an environmental isolation effect, avoiding the influence of the sudden change of the surface temperature on the deformation of the steel, enabling the free expansion and contraction amount of the 10m long steel to reach 3.6mm when the temperature difference DeltaT=30 ℃, and reducing the free expansion and contraction amount to 0.5mm when the steel is buried under the constraint of the land.

All steel parts of the rigid connecting device are subjected to hot dip galvanization corrosion prevention treatment. The hot dip galvanizing process forms a compact zinc layer on the surface of the steel part, effectively isolates the corrosion of air, moisture and the like to the steel part, prevents the steel part from being corroded in the long-term use process, greatly prolongs the service life of the rigid connecting device, ensures that the rigid connecting device meets the safety limit requirements of engineering, reduces the later maintenance cost and improves the reliability and stability of the whole transmission line iron tower foundation.

Drawings

The following describes the embodiments of the present invention in further detail with reference to the drawings.

Fig. 1 shows a schematic structure of a single screw anchor according to the prior art.

Fig. 2 shows a prior art layout of an overhead transmission line pylon foundation.

Fig. 3 shows a schematic of a conventional single screw anchor threaded into the earth.

Fig. 4 shows a side view of a rigid connection provided by an embodiment of the present invention.

Fig. 5 shows a top view of a rigid connection provided by an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a first connection board according to an embodiment of the present invention.

Fig. 7 shows an assembly view of a rigid connection device provided by an embodiment of the present invention to achieve a rigid connection between screw anchor single anchor foundations at 0.5m below ground ± 0.00.

Fig. 8 shows a schematic structural diagram of a screw anchor single anchor foundation provided by an embodiment of the present invention.

Fig. 9 shows a layout of an overhead transmission line tower foundation provided by the novel embodiment of the present embodiment when a single screw anchor is vertically screwed in.

Fig. 10 shows a layout of an overhead transmission line tower foundation according to a novel embodiment of the present invention when a single screw anchor is obliquely screwed in

Detailed Description

The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.

In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected," "connected," and "fixed" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed, directly connected, indirectly connected through an intermediary, or may be in communication with each other between two elements or in an interaction relationship between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween.

In the description of the present embodiment, the terms "upper", "lower", "left", "right", and the like are orientation or positional relationships based on those shown in the drawings, merely for convenience of description and simplicity of operation, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the invention. Furthermore, the terms "first," "second," and the like, are used merely for distinguishing between descriptions and not for distinguishing between them.

A single screw anchor 1 of a screw anchor single anchor foundation of a conventional overhead transmission line tower is shown in fig. 1, and comprises an anchor rod 11, an anchor disc 12, an anchor head 13 and a steel bearing platform 14. The anchor rod 11 is a straight welded pipe or a seamless steel pipe, the anchor disc 12 is a steel plate, and the anchor rod is pressed and processed by special equipment. The anchor rod 11 and the anchor disc 12 are assembled according to the drawing requirements and then welded. According to the stress of the iron tower and the situation of on-site geology, the foundation anchor of the single screw anchor is vertically or rotationally screwed into the soil according to a certain angle according to the foundation root opening size, then the steel bearing platform 14 is arranged at the top end of the foundation anchor and is connected with the tower foot of the iron tower through bolts, and the assembly of the iron tower and the screw anchor foundation is completed.

The overhead transmission line tower foundation is generally formed by four spiral anchor single anchor foundations, and is generally arranged in a square or rectangular cross section, as shown in fig. 2.

However, conventional screw anchor single anchor foundations have exposed a serious problem in practical applications. Whether a single-screw anchor rod is vertically screwed into the soil (shown as a diagram in fig. 3) or is obliquely screwed (shown as b diagram in fig. 3), the steel bearing platform 14 at the top of the anchor rod 11 is extremely easy to be excessively displaced when the tower bears various loads. The displacement sometimes exceeds the related standard requirements, which not only affects the stability of the iron tower foundation, but also can cause potential safety hazards such as iron tower inclination, line faults and the like, thereby greatly limiting the wide application of the spiral anchor single-anchor foundation in practical engineering.

The steel bearing platform is used as a key force transmission component in an overhead transmission line iron tower foundation and is used for connecting a tower leg and a spiral anchor foundation and bearing the important role of transmitting the tower body load (vertical pressure, horizontal force, bending moment and the like) to a foundation, and the mechanical essence of the displacement of the steel bearing platform is the unbalance of external load and foundation counter force. As the test of the American electric power institute (EPRI) shows that the horizontal rigidity of the four-anchor linkage system is only 15 percent higher than that of an independent anchor rod, the cooperative effect among single screw anchors is limited in general cognition, so that the displacement problem of a corresponding steel bearing platform in the prior art is mainly focused on the bearing capacity and the pulling resistance of the single anchor, and the optimization of the integral cooperative effect of the foundation of an overhead transmission line iron tower is rarely considered.

Aiming at the defects of the prior art, the invention provides a rigid connection device 2 for realizing rigid connection between single-anchor foundations of screw anchors, which is positioned at a position of 0.5m below +/-0.00 m on the ground, after four single-screw anchors 1 are screwed into the soil, a trench is excavated between the single-screw anchors 1, then the rigid connection device 2 is fastened between the four single-screw anchors 1 to form rigid connection, and finally the original soil is backfilled to finish construction.

As shown in fig. 4 to 7, the rigid connection device includes a hoop 21, a connection plate integrally fixed to the outer peripheral surface of the hoop 21, and a connection rod 22.

The anchor ear 21 comprises two anchor ear profiles, which are spliced to form an anchor ear shape and are configured to sleeve the rigid connection device 2 on the anchor rod 11 of the single-screw anchor 1 and coaxially arranged with the anchor rod 11.

The direction of the opening 210 formed between the two hoop profiles is perpendicular to the central direction of the tower.

The connecting plate is combined and fixed on the outer surface of one of the anchor ear sectional materials, and the anchor ear sectional materials face to the space formed by the enclosing of the plurality of single screw anchors 1. The connection plates comprise a first connection plate 23 and a second connection plate 24, the first connection plate 23 and the second connection plate 24 are arranged at an angle, and the central line (the dash-dot line in fig. 5) of the included angle alpha between the first connection plate 23 and the second connection plate 24 passes through the tower center O.

The connection rod 22 is combined and fixed to the first connection plate 23, and the second connection plate 24 is configured to be combined and fixed with the connection rod 22 of the rigid connection device 2 of the adjacent spiral anchor single-anchor foundation, so that a plurality of spiral anchor single-anchor foundations forming the overhead transmission line iron tower foundation can be connected end to end for rigid connection.

In one particular embodiment, as shown in fig. 5, the hoop profile includes a semi-circular hoop body 211, and connecting lugs 212 on either side of the hoop body 211. The hoop section is formed by folding and welding steel plates, and the material is Q235B or Q355B.

In the present embodiment, the end portions of the first connection plate 23 and the second connection plate 24 are welded and fixed to the outer peripheral surface of the hoop body 211, and the reverse extension lines of the first connection plate 23 and the second connection plate 24 converge on the central axis of the hoop body 211.

In a specific example, the first connection plate 23 and the second connection plate 24 are symmetrically arranged, and both have the same shape and thickness. The thickness of the first connection plate 23 and the second connection plate 24 is 10-12mm, for example. The proper thickness design enables the connecting plate to have enough bearing capacity when connecting the connecting rod pieces, can stably transfer acting force among all the components, ensures firm connection, and further enhances the overall performance of the rigid connecting device 2.

The connecting lugs 212 are provided with connecting holes, bolts 3 are connected in the connecting holes, and the axial direction of the connecting holes is perpendicular to the axial direction of the hoop body 211. As shown in fig. 5, two bolts 3 arranged in parallel are connected with two connecting lugs 212 on the same side of the hoop section bar, so as to adjust the size of a ring opening between two hoop bodies 211, and the hoops 21 are fixedly sleeved on the corresponding anchor rods 11. During construction, the anchor bolts 21 are tightly held by the anchor rods 11 by tightening the bolts 3, so that the connection between the anchor bolts 21 and the anchor rods 11 is ensured to be tight and reliable, the load can be effectively transmitted, and the whole rigid connecting device 2 can be ensured to work stably.

In one particular embodiment, the inner diameter R of the ferrule body 211 is calculated by the following formula:

R=r+3mm

where r is the outer diameter of the anchor rod 11 to which the anchor ear 21 is connected.

The inner diameter design is convenient for the anchor ear 21 to be fastened and connected with the anchor rod 11 after the construction of the anchor rod 11 is completed, and can ensure proper holding force between the anchor ear 21 and the anchor rod 11, so that the anchor ear 21 is prevented from shaking or falling off on the anchor rod 11, the stability of connection between the rigid connection device 2 and the single-screw anchor 1 can be effectively enhanced, and therefore the anchor ear 21 can be firmly held and tightly held with the anchor rod 11 under various working conditions, and displacement risks are reduced.

In a specific embodiment, the hoop section is formed by folding and welding steel plates, that is, the hoop body 211 and the connecting lugs 212 have the same thickness. In this embodiment, the thicknesses of the hoop body 211 and the connecting lug 212 are 8-12mm, so that the strength of the hoop 21 can be ensured, the material cost and the processing difficulty are both considered, and the hoop 21 is not easy to deform or damage when bearing external force, thereby ensuring the reliability of the whole rigid connecting device 2.

In a specific embodiment, as shown in fig. 4-5, a stiffening rib 213 is fixed between the hoop body 211 and the connecting lug 212 of one hoop section without the mounting plate, and the plate thickness of the stiffening rib 213 is 8mm, so that the stiffening rib has a reinforcing effect, and can enhance the structural strength of the hoop section, so that the hoop 21 can maintain good structural integrity when the anchor rod 11 is tightly held and bears external force, reduce the risk of local deformation of the hoop 21, and further improve the stability of the rigid connecting device 2.

In a specific embodiment, as shown in fig. 4-5, the rigid connection device 2 further comprises a first stiffening plate 25 fixed between the first connection plate 23 and the anchor ear 21, and a second stiffening plate 26 fixed between the second connection plate 24 and the anchor ear 21.

In this embodiment, one end of the first stiffening plate 25 and one end of the first connecting plate 23 far away from the anchor ear 21 are combined and fixed, and the other end of the first stiffening plate and the connecting ear 212 of the anchor ear profile where the connecting plate is located are combined and fixed near the first connecting plate 23, so as to form a triangle-shaped stable structure. The thickness of the first stiffening plate 25 is 10-12mm, and the main function of the first stiffening plate 25 is to strengthen the first connecting plate 23, so that the deformation resistance of the first connecting plate 23 can be effectively improved in the actual stress process, the first connecting plate 23 is prevented from bending or breaking when bearing a large load, the reliability and stability of the whole rigid connecting device 2 are ensured, and the service life of the rigid connecting device 2 is prolonged.

Correspondingly, one end of the second stiffening plate 26 and one end of the second connecting plate 24 far away from the anchor ear 21 are combined and fixed, and the other end of the second stiffening plate and the anchor ear profile where the connecting plate is located are combined and fixed near the connecting lug 212 of the second connecting plate 24, so that a triangular stable structure is formed. The thickness of the second stiffening plate 26 is 10-12mm, and the main function of the second stiffening plate 26 is to strengthen the second connecting plate 24, so that the deformation resistance of the second connecting plate 24 can be effectively improved in the actual stress process, and the second connecting plate 24 is prevented from bending or breaking when bearing a large load, thereby ensuring the reliability and stability of the whole rigid connecting device 2 and prolonging the service life of the rigid connecting device 2.

In a specific embodiment, as shown in fig. 6, the first connecting plate 23 and the second connecting plate 24 are provided with a plurality of fixing holes 20, and as shown in fig. 5, the first connecting plate 23 and the connecting rod piece 22 are connected by the fixing bolts 4, and the second connecting plate 24 and the connecting rod piece 22 of the rigid connection device of the adjacent spiral anchor single-anchor foundation are connected in an end-to-end manner, so that a plurality of spiral anchor single-anchor foundations forming the overhead transmission line tower foundation can be connected in a rigid manner.

In a specific embodiment, the connecting rod 22 is preferably a steel tube or a round steel in order to ensure the structural strength of the rigid connection means 2.

In one embodiment, the anchor ear 21, the connection plate, the connection bar 22, the stiffener 213, the first stiffener 25 and the second stiffener 26 are all hot dip galvanized steel materials. The hot dip galvanizing process can form a compact zinc layer on the surface of the steel part, effectively prevent the steel part from being corroded in the long-term use process, prolong the service life of the rigid connection device 2, enable the rigid connection device to meet the safety limit requirements of engineering, reduce the later maintenance cost and improve the reliability and stability of the whole transmission line iron tower foundation.

Another embodiment of the present invention provides a screw anchor single anchor foundation comprising a single screw anchor 1 and the rigid connection means 2 provided by the above embodiments, as shown in connection with fig. 8. The rigid connection device 2 is combined and fixed on the anchor rod 11 of the single-screw anchor 1 through the anchor hoop 21 and is positioned at the position of the anchor rod 11 close to the top end.

In construction, the single screw anchor 1 comprises two screwing modes, namely vertical screwing and inclined screwing, in fig. 8, a is a schematic structural view of the configuration rigid connection device 2 of the single screw anchor 1 which is vertically screwed, and b is a schematic structural view of the configuration rigid connection device 2 of the single screw anchor 1 which is obliquely screwed, as can be seen from fig. 8, both the first connection plate 23 and the second connection plate 24 of the corresponding rigid connection device 2 of the single screw anchor 1 which is vertically screwed and the single screw anchor 1 which is obliquely screwed are arranged perpendicular to the horizontal ground.

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

The second connecting plate 24 is the same, and specifically, the angle between the second connecting plate 24 and the central axis of the anchor ear 21 varies with the angle at which the anchor rod 11 is screwed into the ground. Specifically, the angle between the second connecting plate 24 and the central axis of the anchor ear 21 is equal to the angle γ between the central axis of the anchor rod 11 and the horizontal ground. When the single screw anchor 1 is vertically screwed in, the second connection plate 24 is welded and fixed to the outer peripheral surface of the anchor ear 21 in the radial direction of the anchor ear 21.

Another embodiment of the present invention provides an overhead transmission line iron tower foundation, as shown in fig. 9-10, including four screw-anchor single-anchor foundations 100 provided in the foregoing embodiments, where the four screw-anchor single-anchor foundations 100 are arranged in a square structure or a matrix structure, and the single screw anchors 1 of the four screw-anchor single-anchor foundations 100 are rigidly connected by a rigid connection device 2. The angle between the first connection plate 23 and the second connection plate 24 of the same screw anchor single anchor base 100 is 90 °. It should be noted that, the angle between the first connection plate 23 and the second connection plate 24 of the same screw anchor single anchor foundation 100 is affected by the number and arrangement structure of the screw anchor single anchor foundations 100, and may be adjusted according to practical situations.

The integral connection mode of the overhead transmission line iron tower foundation is that four single screw anchors 1 are screwed into the soil in the foundation construction, and ditches are firstly dug among the single screw anchors 1 at the position of 0.5m below +/-0.00 m on the ground, and the dug ditches are square or rectangular. The anchor ear 21 is arranged on the single screw anchor 1, the direction of an opening formed between two anchor ear sectional materials is perpendicular to the central direction of the tower position, after the anchor ear 21 is fastened by using the bolt 3, a connecting rod piece 22 (such as a steel pipe or round steel) is arranged on a connecting plate of the anchor ear 21, so that the single screw anchor 1, the anchor ear 21, the connecting plate and the connecting rod piece 22 form an integral rigid connecting device, and after the installation and fastening of the connecting device are completed, the trench is backfilled by undisturbed soil. When the single screw anchor 1 is inclined and screwed in, the inclination direction of the single screw anchor should be directed to the center of the tower or on the opposite extension line of the center of the tower.

The invention provides a construction method of the overhead transmission line iron tower foundation, which comprises the following steps:

Step one, screwing four single-screw anchors 1 into a foundation soil body at a preset angle to form a quadrilateral anchor point array;

Digging four trench grooves in the area between the four single screw anchors 2, wherein the bottom surface of the trench groove is 0.5m below the natural ground elevation, and the plane outlines of the four trench grooves are enclosed to form a rectangular structure;

Step three, installing anchor bolts 21 at the set height of each single-screw anchor 1 and fastening the anchor bolts 21 on the outer peripheral surface of the anchor rod 11 of the single-screw anchor 1 through bolts 3, wherein the direction of an opening 20 formed between two anchor bolt sectional materials positioned on the same single-screw anchor 1 is perpendicular to the central direction of a tower position;

Fixedly mounting a connecting rod piece 22 on a first connecting plate 23 of each rigid connecting device 2 through a fixing bolt 4 in the ground groove, and fixedly connecting the other end of the connecting rod piece 22 with a second connecting plate 24 of the rigid connecting device 2 on the adjacent single-screw anchor 1;

backfilling the land trench with undisturbed soil and compacting.

When the single screw anchor 1 is screwed into the foundation soil body at an inclined angle, the axis extending direction of the single screw anchor is directed to the center of the tower or is positioned on the reverse extension line of the center of the tower. When the single screw anchor which is obliquely screwed in points to the tower center O, the axis of the single screw anchor and the force transmission direction of the tower leg form a collinear or small-angle relation, so that horizontal load (such as wind load) is converted into axial tension through the inclination angle of the anchor rod, bending moment components are reduced, and the anti-pulling efficiency is improved.

In the construction method of the overhead transmission line iron tower foundation, provided by the embodiment of the invention, four single-screw anchors are connected through the rigid connecting device to form a closed square frame structure, the original independent anchoring points are integrated into a space steel frame structure, the uniform distribution of load can be realized, single-point stress concentration is avoided, horizontal torque and eccentric load can be resisted through the integral geometric stability, and local deformation is converted into cooperative deformation of the integral structure by utilizing the axial rigidity and bending resistance of the connecting rod pieces.

In addition, four single screw anchors are connected through the rigid connection device, a truss effect can be formed, lateral constraint is carried out on each single screw anchor, lateral displacement at the top of an anchor rod is limited, 80% of horizontal load is converted into axial force of a formed closed direction frame structure through the design of the embodiment, the horizontal load is not offset only by means of shearing resistance of a steel bearing platform in the prior art, so that displacement of the steel bearing platform can be avoided, bending moment generated by asymmetric load can be offset internally, accumulated plastic deformation at the connecting point of the anchor rod and the steel bearing platform is avoided, and bad displacement of the steel bearing platform is avoided.

Because the rigid connecting device is positioned at the position of 0.5m below the ground plus or minus 0.00 and needs original soil backfilling after being installed, the passive resistance of the soil can be fully utilized to form an effect similar to an invisible ground beam, and the friction force between the connecting rod piece buried underground and surrounding soil body enables the soil body to form a mechanical stop for the formed square frame structure, the moving space of the steel bearing platform is physically limited, and the anti-sliding capacity of the single-screw anchor is enhanced. In addition, the method has the advantages of having an environmental isolation effect, avoiding the influence of the sudden change of the surface temperature on the deformation of the steel, enabling the free expansion and contraction amount of the 10m long steel to reach 3.6mm when the temperature difference DeltaT=30 ℃, and reducing the free expansion and contraction amount to 0.5mm when the steel is buried under the constraint of the land.

According to the rigid connection device, the spiral anchor single-anchor foundation, the overhead transmission line iron tower foundation and the construction method thereof provided by the embodiment of the invention, the traditional passive displacement resistance thought is changed into the wisdom of actively guiding a load path through the design of the flexible steel, so that the gist of 'homeopathic' of modern geotechnical engineering is embodied. Through finite element analysis, the rigid connecting device provided by the invention coordinates deformation among the single screw anchors, so that the horizontal rigidity of a four-anchor linkage system is improved by 30-50% compared with that of an independent anchor rod, the displacement of a steel bearing platform is reduced by 20-40%, the four single screw anchors are connected through the rigid connecting device to form a closed square frame structure, an anti-overturning couple can be formed, and the anti-overturning coefficient of an overhead transmission line iron tower foundation is improved by 1.2-1.5 times.

It should be understood that the foregoing examples of the present invention are provided merely for clearly illustrating the present invention and are not intended to limit the embodiments of the present invention, and that various other changes and modifications may be made therein by one skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims (10)

1. The rigid connecting device is used for rigid connection between screw anchor single anchor foundations and is characterized by comprising an anchor ear, a connecting plate and a connecting rod piece, wherein the connecting plate is combined and fixed on the outer peripheral surface of the anchor ear;

the anchor ear comprises two anchor ear sectional materials which are spliced to form an anchor ear shape and are configured to be sleeved and fixed on an anchor rod of a single-screw anchor and coaxially arranged with the anchor rod;

the direction of an opening formed between the two hoop sections is perpendicular to the central direction of the tower;

The connecting plates are combined and fixed on the outer surface of one of the hoop sectional materials, the connecting plates comprise 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 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 is fixedly combined with the first connecting plate, and the second connecting plate is fixedly combined with 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, wherein the anchor ear profile includes a collar body including a semicircular ring shape, and connection lugs located at both sides of the collar body, ends of the first connection plate and the second connection plate are integrally fixed to an outer circumferential surface of the collar body, and reverse extension lines of the first connection plate and the second connection plate converge on a central axis of the collar body;

The connecting lugs are provided with connecting holes, bolts are connected in the connecting holes, and the axial direction of the connecting holes is perpendicular to the axial direction of the hoop body;

the two anchor ear profiles are connected through the two parallel bolts and are positioned on the same side of the connecting lugs, so that the size of a loop opening between the two anchor ear bodies is adjusted, and the anchor ear is fixedly sleeved on the anchor rod.

3. The rigid connection as claimed in claim 2, wherein the inner diameter R of the ferrule is calculated by the formula:

R=r+3mm

And r is the outer diameter of the anchor rod connected with the anchor hoop.

4. The rigid connection device according to claim 2, wherein stiffening ribs are fixed between the hoop body and the connecting lugs of the other hoop profile;

The thickness of the hoop body is 8-12mm, and the thickness of the stiffening rib is 8mm.

5. The rigid connection device of claim 2, further comprising a first stiffening plate secured between the first connection plate and the anchor ear, and a second stiffening plate secured between the second connection plate and the anchor ear;

One end of the first stiffening plate is combined and fixed with one end of the first connecting plate far away from the anchor ear, and the other end of the first stiffening plate is combined and fixed with the connecting ear, close to the first connecting plate, of the anchor ear section bar where the connecting plate is located;

One end of the second stiffening plate is combined and fixed with one end of the second connecting plate far away from the anchor ear, and the other end of the second stiffening plate is combined and fixed with the connecting lug, close to the second connecting plate, of the anchor ear profile where the connecting plate is located;

the thickness of the first connecting plate is 10-12mm, and the thickness of the second connecting plate is the same;

the thickness of the first stiffening plate is 10-12mm, and the thickness of the second stiffening plate is the same.

6. The rigid connection device according to claim 1, wherein a plurality of fixing holes are formed in each of the first connection plate and the second connection plate, the first connection plate and the connection rod are connected through fixing bolts, and the second connection plate and the connection rod of the rigid connection device of the adjacent screw anchor single anchor foundation.

7. A screw anchor single anchor foundation comprising a single screw anchor and a rigid connection device as claimed in any one of claims 1 to 6;

the rigid connecting device is fixed on the anchor rod of the single-screw anchor through anchor ear combination.

8. The screw anchor mono-anchor foundation of claim 7, wherein the angle between the central axes of the first web and anchor ear and the angle between the central axes of the second web and anchor ear varies with the angle at which the anchor rod is screwed into the ground;

the angle between the first connecting plate and the central axis of the anchor ear is equal to the angle between the central axis of the anchor rod and the horizontal ground;

The angle between the central axis of second connecting plate and staple bolt equals the angle between the central axis of stock and the level ground.

9. An overhead transmission line iron tower foundation, which is characterized by comprising four spiral anchor single-anchor foundations according to any one of claims 7-8, wherein the four spiral anchor single-anchor foundations are arranged in a rectangular structure, and single spiral anchors of the four spiral anchor single-anchor foundations are rigidly connected through the rigid connecting device;

the angle between the first connecting plate and the second connecting plate of the single anchor foundation of the same spiral anchor is 90 degrees.

10. A method of constructing an overhead transmission line pylon foundation of claim 9 comprising:

screwing the four single-screw anchors into the foundation soil body at a preset angle to form a quadrilateral anchor point array;

Digging four trench grooves in the area between the four single screw anchors, wherein the bottom surface of the trench groove is 0.5m below the natural ground elevation, and the plane outlines of the four trench grooves are enclosed to form a rectangular structure;

Installing anchor bolts at the set height of each single-screw anchor and fastening the anchor bolts on the outer peripheral surface of the single-screw anchor rod through bolts, wherein the direction of an opening formed between two anchor bolt sectional materials positioned on the same single-screw anchor is perpendicular to the central direction of the tower;

Fixedly mounting a connecting rod piece on a first connecting plate of each rigid connecting device through a fixing bolt in a trench, and connecting and fixing the other end of the connecting rod piece with a second connecting plate of the rigid connecting device on an adjacent single-screw anchor;

backfilling the land groove with undisturbed soil and compacting;

When the single screw anchor is screwed into the foundation soil body at an inclined angle, the axis extending direction of the single screw anchor points to the center of the tower or is positioned on the reverse extension line of the center of the tower.