WO2020236040A1

WO2020236040A1 - Screw pile

Info

Publication number: WO2020236040A1
Application number: PCT/RU2020/050106
Authority: WO
Inventors: Валерий Владимирович Желтиков
Original assignee: Zheltikov Valerij Vladimirovich
Priority date: 2019-05-22
Filing date: 2020-05-22
Publication date: 2020-11-26
Also published as: GEU20222140Y

Abstract

The invention relates to the field of construction, more specifically to screw piles. There is currently quite a large number of different variants of screw piles on the market that differ from one another by production method, method for processing pile shoes, welding on a helix and the type of helix itself, etc. The technical problem which is solved by such a pile design is to extend the possibility of using a pile, which is produced by a rotary swaging method, in plastic and unstable soils, that is to improve the performance characteristics. The claimed technical solution achieves the technical result consisting in increasing the reliability of a pile during use in plastic and unstable soils.

Description

Screw pile

[0001] The invention relates to the field of construction, namely, to screw piles. At the moment, a fairly large number of different options for screw piles are presented on the market, differing from each other in the production method, the method of processing the tips, welding the spiral and the type of the spiral itself, etc.

[0002] Screw piles are easy to use, due to the possibility of their operation in difficult terrain, frozen soil, on soils with high humidity, peaty, clayey, sandy, with heterogeneous soil. Also, the variety in the length of the pile, its flange and other type of fastening allows them to be used in the construction of various structures and structures in construction.

[0003] BACKGROUND

[0004] There is a known solution (RU 170105, E02D 5/56, publ. 04.14.2017) for making piles from a pipe and a cast tip by joining pile elements by welding, by means of ring welding.

[0005] The disadvantage of this solution is the implementation of a circular welded connection of the elements, which reduces the reliability of the pile and forms the possibility of separation of the tip from the barrel. Also, the disadvantage of this technical solution is the complexity of centering the pile when screwing in, since there is a high risk of mismatching the center line of the tip with the center axis of the pile shaft.

[0006] Also known is a technical solution (RU 114692, E02D 5/56, publ. 10.04.2012) for the manufacture of piles from a cylindrical pipe with a conical lower part, on which a blade is welded with chamfers applied to its surface.

[0007] The disadvantage of this solution is the complexity of technological production in applying chamfers to the surface of the blade.

[0008] The closest analogue to the claimed technical solution is a utility model (RU 120426, E02D 5/56, publ. 09/20/2012), which includes a metal pipe with an anticorrosive coating, with a conical bottom, a metal winding in the form one turn of the blade located on the conical part of the pipe, characterized in that the conical part of the pile is made in the form of a pyramid with at least three edges, the width of the winding blade is at least 1/3 of the outer diameter of the pipe, the blade pitch is from one to two outer diameters pipe, and at the upper end of the pipe on its lateral surface is made at least one technological hole. [0009] A significant disadvantage of this invention is that in the manufacture of the pile the tip is welded to the metal pipe. This creates the risk of the pile tip breaking off when screwing into the ground and the misalignment of the pile tip axes with the center axis of the trunk.

[0010] TERMS AND DEFINITIONS

[0011] A screw pile is a type of pile buried in the ground by the screwing method, including in combination with indentation. Screw piles consist of a cylindrical part, a tapered part with a spiral or a blade, a tip, a head, and possibly a flange.

[0012] The cylindrical part is a part of a pile made from a pipe with a constant diameter that has not undergone machining of the billet shape.

[0013] A tapered portion is a portion of a pile made from a pipe that has undergone mechanical and heat treatment in order to obtain a given taper and improve the strength characteristics of the starting material.

[0014] Pile Narrowing - reducing the diameter of the pile body along its length. It can be conical, parabolic, exponential, or with any other law of decreasing diameter along length. In general, it is given by the ratio of the change in diameter to the change in the longitudinal distance between the places where the diameter is measured. It is possible to express the constriction as a percentage, where the change in diameter along the length is divided by the distance between the diameter measurement points and multiplied by 100.

[0015] A seam pipe is an original steel pipe with a joint along its entire length, according to GOST 10704-91, GOST 28548-90, GOST 10705-80, GOST 10707-80, GOST 10706-76, GOST 11068-81, GOST 30456- 97, can be used, inter alia, a pipe with a diameter of 57, 76, 89, 108, 114 mm., A wall thickness of 3 to 4.5 mm., A possible material for the manufacture of a pipe - carbon and low-carbon Steel 3 and Steel 5, or their analogues. It is used as a blank for the manufacture of a pile body by hot rotary forging.

[0016] A tip is the portion of a pile that enters the ground first when the pile is installed.

[0017] Blade - a strip element of the pile, welded spirally to the pile shaft, intended for immersing the pile in the ground along the axis when the pile rotates around its axis.

[0018] The polyhedral pyramid is the shape of a pile head, formed by rotary forging until the internal cavity disappears and turned into a monolithic core with edges.

[0019] Lancet - the shape of a polyhedral pyramid of a pile tip, obtained by forging into a monolithic element. In cross section has the form rhombus. This type of tip facilitates passage through plant roots, debris and stones in the ground.

[0020] A weld seam is a zone of a permanent connection made by welding. Differs in lower mechanical and chemical properties in comparison with the joined steel, due to the possible presence of cavities, pores and other defects.

[0021] Rotary forging is a forging performed in a radial compression pattern. In a rotor with holes, strikers (two or more) move along the guides with one degree of freedom. The rotor with strikers can rotate. When rotating, the strikers strike the forging from diametrically opposite sides.

[0022] Forge welding - "Forging welding", a type of pressure welding with heat treatment. Through it, an integral connection is formed as a result of the action of a forging percussion tool on a metal in a plastic state.

[0023] Forging - (upsetting and upsetting), a forging operation, which consists in deformation of a workpiece by partial upsetting in order to create local thickenings by reducing the length (or other size) of the workpiece.

[0024] Condensate - water formed during condensation of water vapor on the walls of metal parts, in particular, in cavities with access to atmospheric air.

[0025] The inner cavity is the space of the tubular element not filled with material.

[0026] Head - The upper area of the pile, protruding above the ground or located at the ground level, may also have a flange, jibs, and the like.

[0027] Flange - a piece of square, round or other shape with holes for bolts and studs, used to connect prefabricated pile elements to each other, to the above structural elements of a building or structure, as well as to equipment for various functional purposes.

[0028] Seam curvature on the tapered portion is the deviation of the seam from the plane formed by the pile axis and the bare seam. Can be measured in degrees or percent. The pipe is laid horizontally with the seam upwards, a ruler is applied along the unforged seam so that part of the ruler passes over the tip. From the ruler to the narrowing, a perpendicular is lowered to the axis of the pile, which forms the projection point of the initial seam on the surface of the narrowing. Perpendicular to the pile axis along the surface of the circle, the distance from the projection point to the real seam is measured. This deviation is divided by the distance from the projection point to the beginning of the forging zone and multiplied by 100, which shows the amount of weld curvature in percent.

[0029] SUMMARY OF THE INVENTION [0030] The technical problem that is solved by such a pile design is the expansion of the possibility of using a pile obtained by the rotary forging method in plastic and fluid soils, that is, an improvement in operational characteristics.

[0031] The claimed technical solution achieves such a technical result as an increase in the reliability of the pile when operating in plastic and fluid soils.

[0032] The term "operation" of a pile means the installation and further use of the pile for its intended purpose.

[0033] This technical result is achieved due to the fact that a pile made of a seam steel pipe by hot rotary forging, and consisting of a cylindrical part, a tapering part with a gradually decreasing diameter and formed at the end of the tip, has at least one blade, width which ranges from 150 - 800 mm.

[0034] The aforementioned pile is made of a seam steel pipe by hot rotary forging, while the pile tip is made in one piece, thereby minimizing the risk of tip separation and ensuring the centering of the tip center axis with the pile shaft center axis, which allows achieving the claimed technical result.

[0035] It is also worth noting that rotary forging allows the formation of a tapered part of the pile with a gradual decrease in the diameter of the pile shaft from 2 to 30%, which leads to an improvement in the penetration of the pile and optimization for the use of low-moment installation mechanisms. As a consequence, this leads to convenience and ease of installation.

[0036] The width of the pile blade is made from 150 to 800 mm. With blades less than 150 mm wide. it is much more difficult, and in some cases impossible, to use a screw pile in plastic soils. Welding blades with a width of more than 800 mm. is not technologically advanced and difficult to manufacture. These values are obtained by testing at the applicant's production site.

[0037] The blade, welded in the claimed screw pile, can be single or double turns. The multi-turn structure of the pile increases the strength and the bearing capacity, including in heterogeneous soils, facilitates installation and better holds the pile in plastic soil.

[0038] More than one blade can also be welded to the screw pile shaft to provide greater stability in ductile and fluid soils. Moreover, the blades can be welded to both the tapered part and to the tapered and cylindrical. [0039] The claimed screw pile has a tip made in the form of a polyhedral pyramid tip, which can be additionally compressed to a lanceolate one. The lance-shaped tip in the form of a polyhedral pyramid strengthens the tip itself against horizontal bending loads and allows the unconsolidated soil elements to move away from the pile, which significantly reduces the likelihood of the auger belt breaking at the head of the pile. The lance-shaped tip in the form of a polyhedral pyramid provides easier penetration of the pile into the ground, where the lance-shaped edges of the pile tip simultaneously cut through the parent soil and shift inclusions of non-compactable soil elements (pebbles, roots, etc.) away from the pile.

[0040] All of the above features of the claimed technical solution are aimed at achieving the specified technical result, namely, increasing the reliability of the pile when operating in plastic and fluid soils.

[0041] DESCRIPTION OF THE DRAWINGS

[0042] The implementation of the invention is described in the following in accordance with the accompanying drawings, which are presented to explain the essence of the invention and in no way limit its scope.

[0043] The following drawings are attached to the application:

[0044] Fig. 1 illustrates a general view of a single-blade pile with welded single-turn blade;

[0045] FIG. 2 illustrates a general view of a multi-blade pile with welded single-turn blades.

[0046] Fig. 3 illustrates a general view of a pile with a welded two-turn blade.

[0047] In these drawings, the following positions are indicated:

[0048] 1 - forged lancet tip;

[0049] 2 - cone with variable diameter;

[0050] 3 - blade;

[0051] 4 - pile shaft with constant diameter;

[0052] 5 - head;

[0053] 6 - holes for controlling the degree of transformation of steel by the geometric parameters of the weld.

[0054] DETAILED DESCRIPTION OF THE INVENTION

[0055] In the following detailed description of the implementation of the invention, numerous implementation details are given in order to provide a clear understanding of the present invention. However, it will be obvious to a person skilled in the art how the present invention can be used with or without these implementation details. In other instances, well-known techniques, procedures, and components are not described in detail so as not to obscure the details of the present invention.

[0056] In addition, it is clear from the foregoing disclosure that the invention is not limited to the foregoing implementation. Numerous possible modifications, changes, variations and substitutions, while retaining the spirit and form of the present invention, will be apparent to those skilled in the art.

[0057] This invention is aimed at achieving such a technical result as increasing the reliability of the pile when operating in plastic and fluid soils. Achievement of this technical result is possible due to the implementation of the pile by the method of hot rotary forging, but at the same time the blade, welded to the pile shaft, has a width of 150 to 800 mm.

[0058] The width of the blade can be either constant or variable. Constant width is more technologically advanced in manufacturing, since the blade is made of a metal strip, 5 to 10 mm thick, 150 to 800 mm wide.

[0059] Due to the fact that the ferrule is formed inseparably from the seam tube by hot rotary forging, which includes preheating the seam pipe, radial reduction of the steel seam pipe by hot forging to form a solid ferrule, including in the form of a polyhedral pyramid with crimping into a lanceolate shape, thus reducing the risk of the tip breaking off when screwing in the pile, the risk of premature metal corrosion, increasing the strength of the tip. Rotary forging of the tip occurs exactly until the gap at the end of the pile disappears, which excludes the possibility of soil getting into the inner cavity of the pile. The temperature at which this technological operation is carried out is sufficient for the implementation of "forging welding" - complete, without traces of a seam, filling the inner volume of the pile tip and joining all metal layers into a monolithic body.

[0060] Thus, during the thermal forging process, it becomes possible to form a lance-shaped pile tip, which has a diamond-shaped cross-section to ensure easier penetration of the pile into the soil, where the lance-shaped edges of the pile tip simultaneously cut through the parent soil and shift inclusions of non-compactable soil elements (pebbles, roots, etc.) away from the pile. In the same way, with rotary forging, a tip can be formed into the shape of a polyhedral pyramid. The presence of the shape of the multi-faceted pyramid of the tip strengthens the tip itself against horizontal bending loads and allows the expansion of uncompacted soil elements from the pile, which significantly reduces the likelihood of the auger belt breaking at the head of the pile, the edges of the pyramid are less susceptible to bending and wear during soil compaction. The additional lancet shape of the tip gives the pile better penetration properties.

[0061] The claimed invention also has a single-turn or two-turn blade, the width of which varies from 150 to 800 mm, depending on the diameter of the pile body. Examples:

[0062] The data presented in the table in the section "Weight of the finished product (galvanized)" are indicative and may have minor changes depending on the raw materials used in the production.

[0063] These blades are welded to the tapered part of the pile, and can also be welded simultaneously to both the cylindrical and the tapered part of the screw pile. The beginning of the pile welding point is performed above the tip, and therefore, during the installation process, the tip ensures that the pile body is cut into the ground.

[0064] It should also be noted that previously conducted experimental studies of the claimed invention have shown that the optimal ratio of reducing the body diameter along the length of the pile at the base and the top of the tapering section of the pile is in the range from 2 to 30%, and for different applications the taper can be conical, parabolic , exponential. In general, the narrowing is given by the ratio of the change in diameter to the change in the longitudinal distance between the places where the diameter is measured. It is possible to express the constriction as a percentage, where the change in diameter along the length is divided by the distance between the diameter measurement points and multiplied by 100. This range is optimized for the use of low-torque installation mechanisms. Thus, a ratio of 30% is most optimal for machine installation, and a ratio of 2% is more suitable for manual installation.

[0065] Additionally, holes can be made in the pile to remove condensate and estimate the thickness of the forged material and geometry of the inner part of the seam, which are located at the boundary of the zone of disappearance of the gap in the inner cavity. Such holes can be made perpendicular to the pile axis, or at an acute angle to the longitudinal axis of the pile.

[0066] A weld bend angle is defined as the angle between an axis and a tangent to the bead curve. It should be borne in mind that the surface on which the angle is measured is not flat. To compensate for the curvature of the surface, the projection of the point of intersection of the seam from the axis to the continuation of the cylindrical surface of the pipe is introduced (sweep). On a cylindrical projection unfolded into a plane, the angle between the continuation of the projection of the straight seam line to the tangent to the projection of the curved seam line will be the angle of deflection of the seam.

[0067] A weld bend angle is defined as the angle between an axis and a tangent to the bead curve. It should be borne in mind that the surface on which the angle is measured is not flat. To compensate for the curvature of the surface, the projection of the point of intersection of the seam from the axis to the continuation of the cylindrical surface of the pipe is introduced (sweep). On a cylindrical projection unfolded into a plane, the angle between the continuation of the projection of the straight seam line to the tangent to the projection of the curved seam line will be the angle of deflection of the seam.

[0068] The measurement of the angle in this case looks like this: the pile is placed horizontally on two supports with the seam up. From above, the probe is vertically lowered to the point of the beginning of the bend of the seam (the beginning of the forged zone) and fixed. The pile is shifted axially towards the head by a distance S, rotated so that the seam is under the probe, the angle L of the pile rotation around its axis (in degrees) is measured. The angle of rotation is converted into a distance on the projection using the formula S = pi * D * L / 360, where S is the distance, mm .; D - diameter of unforged pipe, mm .; L - angle, degrees; pi is pi. Next, a scan of the projection of the seam of the tapering part is drawn in points every 10 mm. (or another distance sufficient for measurement accuracy), the seam projection curve is obtained. Then tangents to the projection curve of the seam and the protractor or protractor measure the angle between the resulting tangent and the projection of the axis.

[0069] When a given geometry of a pipe product is achieved by the rotary forging method, the effect of steel yield is observed, expressed, for example, in a change in the relative dimensions of the weld from the initial shape - from the ring sector in the section to a wedge-shaped one (the change in the ratio of the weld width to its thickness as the pipe diameter). In this case, there are changes in the dimensions of the seam zone, blurring boundaries "seam material - pipe material", changing characteristics of the seam material in the direction of increasing mechanical parameters and an increase in corrosion resistance. There are also deviations of the longitudinal seam of the pipe from the line lying in the same plane with the axis of the pile, as well as the curvature of the initially straight weld in the form of a spiral line (left or right).

[0070] The Applicant's trial production showed that, in particular, a pile made from a seam pipe shows a change in seam width from 6 mm. up to 4 mm., seam thickness from 4 mm. up to 8.4 mm. in the area of the hole by 390 mm. narrowing and deviation of the line of the original seam from the parallel axis of the pile by 23 mm. 360 mm. the tapering part of the pile. An example of calculating the change in the linear dimensions of a seam:

[0071] - the width of the seam on the unforged part was 6 mm, on the forged part it became 4 mm. 6mm / 4mm. = 1.5 times. (1.5-1) * 100 = 50% difference. The set value of 20% has been exceeded, which means that this validity parameter has been met.

[0072] - the thickness of the seam on the non-forged part was 4 mm, on the forged part it became 8.4 mm. 8.4 mm. / 4 mm. = 2.1 times. (2.1-1) * 100 = 110%. The set value of 20% has been exceeded, which means that this validity parameter has been met.

[0073] Since the seal and bead thickening and curvature are the result of rotary hammering, bending of the bead can be taken as an additional criterion.

[0074] It is important to be able to control the initial wall thickness of the unforged original pipe. Since the end of the pile is closed with a flange, a round or oval-shaped through hole (control window) is made in it, which falls on the end of the seam and allows one to estimate the initial metal thickness of the pipe wall and the shape of the seam in the section.

[0075] In case of plastic deformation of steel, to remove possible internal stresses and to increase the toughness of the material, tempering of the product is used. As a result of tempering, the steel retains high hardness, but quenching brittleness is eliminated. Conversion of quenched martensite to tempering martensite helps to stabilize the dimensions of the part, increases strength and elasticity at medium hardness.

[0076] For additional chemical resistance and anti-corrosion effect, the pile can be hot or cold galvanized.

[0077] The screw pile contains a seam pipe barrel, the lower part 2 of which, by means of hot rotary forging is narrowed, a tip 1 is formed, which is a forged welded monolith of ductile-deformed steel, having the shape of a polyhedral pyramid or a lance-shaped end of the pile. On the border of the narrowing and the tip, holes 6 are made to control the degree of transformation of the steel according to the geometric parameters of the weld.

[0078] A single-turn or two-turn blade 3 made of steel tape is welded onto the tapering body of the pile molded by hot rotary forging to form a screw and the possibility of rotating the pile into the ground. The weld is made continuously along the formed helix. On the shaft of a pile with a constant diameter of 4, a pile head 5 is made, a flange is attached and fixed by welding, to redistribute the bearing load from external structures, through the body of the pile to the ground.

[0079] In the present application materials, the preferred disclosure of an implementation of the claimed technical solution is presented, which should not be used as limiting other, particular embodiments of its implementation, which do not go beyond the scope of the claimed scope of legal protection and are obvious to specialists in the relevant field of technology.

Claims

Formula

1. A helical pile made of a seam steel pipe by hot rotary forging, and consisting of a cylindrical part, a tapering part with a gradually decreasing diameter and a tip formed at the end, on which at least one blade is located, the blade width being from 150 to 800 mm.

2. A screw pile according to claim 1, characterized in that the blade is welded to the cylindrical part;

3. Screw pile on and. 1, characterized in that the blade is made of one-cycle,

4. A screw pile according to claim 1, characterized in that the blade is made of two turns.

5. A screw pile according to claim 1, characterized in that it is multi-blade.

6. A screw pile according to claim 1, characterized in that the narrowing of the pile has a value from 2 to

thirty%.

7. A screw pile according to claim 1, wherein the tip is formed in one piece.

8. A screw pile according to claim 1, characterized in that the tip of the pile has the shape of a polyhedral pyramid.

9. A screw pile according to claim 8, wherein the tip has a lanceolate shape.