Offshore wind turbine uplift pile

Abstract

The invention provides an offshore wind turbine uplift pile which is characterized in that a pile body comprises an outer side cylinder and an inner side cylinder, and a plurality of columns of uplift pieces are arranged in the outer side cylinder in the longitudinal direction of the outer side cylinder; the inner side rotating shaft is fixedly mounted on the inner wall of the inner side cylinder; one side edge of the anti-pulling angle is connected to the inner side rotating shaft, so that the anti-pulling angle can rotate upwards around the connecting point of the inner side rotating shaft and the inner side barrel until the anti-pulling angle makes contact with the inner wall of the inner side barrel, and the anti-pulling angle can be unfolded downwards under the acting force of a soil body when playing an anti-pulling role; the inner anti-pulling piece rotates downwards to drive the baffle to move upwards so that the telescopic piece can be driven into soil, and the inner anti-pulling piece and the outer anti-pulling piece play an anti-pulling role at the same time. Automatic unfolding is achieved through the action effect of a soil body, the pulling resistance of the uplift pile is improved while the contact area of the uplift pile and the soil body during driving is reduced, the overall performance is good, and the uplift pile has good practicability while the structural strength of a pile foundation is enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of offshore wind power, and in particular relates to an offshore wind turbine pull-out pile. Background Art

[0002] The offshore wind turbine barbed pull-out pile technology is a foundation treatment method developed specifically to meet the special needs of wind power generation facilities in the marine environment. Since offshore wind farms are usually located in deep waters and face complex geological conditions and extreme environmental loads (such as currents, waves, storms, etc.), traditional pull-out pile technology may not meet its requirements for stability and durability. Therefore, barbed pull-out piles, as an enhanced foundation solution, have been widely used in the offshore wind power field.

[0003] Pull-out piles are a common anti-liquefaction measure in liquefied sites, and are also often used as anti-floating measures in underground structure design. The common pull-out piles in the prior art are mostly spiral soil-squeezing cast-in-place piles, which mainly rely on the friction between the pile body and the soil layer to resist axial tension. The existing pull-out piles have many shortcomings during use. When the piles are axially compressed, they expand laterally and shrink laterally when they are pulled. This causes the traditional pull-out piles to not only need to be inserted into the ground under greater pressure, but also only receive friction resistance in the vertical direction without horizontal linkage. It is not only time-consuming and laborious when pressed into the ground, but also has poor pull-out stability. Common measures include increasing the foundation weight and using pull-out anchors, but ordinary pull-out piles mainly provide pull-out resistance through the side friction resistance of the piles, and the pull-out resistance is limited, or too complex to be implemented. Taking the single pile foundation of offshore wind power as an example, as the load increases, the pile body diameter is large, the length is large, and the burial depth is deep. However, the cost-effectiveness of conventional pile foundations in mobilizing the resistance of the surrounding rock and soil is relatively low, making them less than ideal in terms of material consumption, construction difficulty, and comprehensive cost.

[0004] After searching, I found a Chinese patent with publication number CN220318512U. The pull-out pile is a high-strength prestressed pile with spaced spiral ribs. Multiple rows of spiral ribs are arranged with a preset number of spiral teeth at a predetermined spacing. The pile mainly relies on the friction between the pile body and the soil layer to resist the axial tension. Although the spiral teeth can reduce the friction resistance of the screw into the soil layer, the improvement of the pull-out resistance is limited, and it is only subject to friction resistance in the vertical direction without horizontal linkage. It requires a larger burial depth, and the spiral construction method is difficult and costly. It is difficult to achieve basic construction requirements when encountering uncertain soil layers.

[0005] After searching, a Chinese patent with publication number CN118653503A was found. The offshore wind power multi-pile foundation platform is connected with multiple pile foundation rods. The multiple pile foundation rods are inclined and rely on the limit mechanism to control the bottom hanging rod and spring action to enhance the pull-out resistance. However, the bottom control device is complex in structure, and when pulled upward, the hanging rod has a limited deployment angle, a small contact area with the soil, and limited pull-out resistance. In addition, the hanging rod is rotated and deployed in the soil by relying on the spring elastic force, which is difficult to achieve and has a low cost-effectiveness. There are many components in the structure and the integrity is weak.

[0006] Therefore, it is necessary to develop an offshore wind turbine barbed pull-out pile that can be easily driven into the soil and greatly improves the pull-out resistance. Summary of the invention

[0007] The purpose of the present invention is to solve the deficiencies in the prior art and propose an offshore wind turbine pullout pile. The technical solution adopted is as follows:

[0008] A pull-out pile, characterized in that the pull-out pile comprises a two-layer cylindrical structure, an internal pull-out member, an external pull-out member and a connecting member, wherein:

[0009] The two-layer cylinder structure comprises an outer cylinder and an inner cylinder, both of which are hollow tubular structures that penetrate from top to bottom, and the outer cylinder is sleeved on the outer side of the inner cylinder; the inner cylinder and the outer cylinder are fixedly connected;

[0010] The internal anti-pulling member includes an anti-pulling angle and an inner rotating shaft; the inner rotating shaft is fixedly installed on the inner wall of the inner tube; the anti-pulling angle is a triangular structure, one side of the triangular structure is connected to the inner rotating shaft so that the anti-pulling angle can rotate upward around the connection point between the inner rotating shaft and the inner tube until the anti-pulling angle contacts the inner wall of the inner tube. When the anti-pulling angle plays an anti-pulling role, it will be expanded downward by the force of the soil. The upper and lower parts are determined by the direction of the anti-pulling pile along the wall of the outer tube when the anti-pulling pile is in the working state. The expansion length of the anti-pulling angle is determined by formula (1):

[0011]

[0012] Where: l0 is the length of the oblique section of the pull-out angle, θ is the rotation angle of the pull-out angle, and r is the radius of the rotation axis;

[0013] The external anti-pullout component includes a telescopic component, a spring, a launch tube and a baffle; the bottom of the launch tube is connected to the outer wall of the inner tube, and the launch tube hole is connected to the outer tube; the outer tube wall is provided with an opening penetrating the outer tube wall at a position coincident with the launch tube hole;

[0014] When the pull-out pile is driven into the soil, the baffle blocks the telescopic member in the launch tube by blocking the launch tube hole. At this time, the spring is located at the bottom of the launch tube and is in a compressed state.

[0015] The connecting member comprises an outer rotating shaft, a connecting rod, a connecting structure 1 and a connecting structure 2, and the inner rotating shaft, the outer rotating shaft, the connecting structure 1, the connecting rod, the connecting structure 2 and the baffle are connected in sequence; wherein the inner rotating shaft and the outer rotating shaft rotate synchronously and in opposite directions and at the same rotation angle; the connecting structure 2 is located below the connecting structure 1;

[0016] When the pull-out pile is subjected to a pulling force, the pull-out angle is affected by the force of the soil and expands downward, driving the inner rotating shaft to rotate downward, and then driving the outer rotating shaft to rotate upward, and then driving the baffle to move upward through the connecting structure 1, the connecting rod, and the connecting structure 2 in sequence, releasing the telescopic part in the launching tube into the soil.

[0017] Preferably, the elastic force provided by the spring is determined by formula (2), the accommodation volume of the launch tube is determined by formula (3), the baffle is tightly fitted with the outer wall of the outer tube, the telescopic member is a large-volume steel needle, and its volume is determined by formula (4); the displacement size of the baffle is determined by formula (5);

[0018]

[0019] L=l1×cosθ1 (5)

[0020] In the formula: k is the elastic coefficient of the spring, x is the deformation of the spring, R is the inner tube radius, r1 is the cross-sectional radius of the launching tube, r2 is the cross-sectional radius of the telescopic part, h2 is the length of the cylindrical part of the telescopic part, h3 is the length of the conical part of the telescopic part; l1 is the length of the rod of the connecting part, and θ1 is the rotation angle of the connecting rod.

[0021] Preferably, the external anti-pullout parts and the internal anti-pullout parts form a group of linkage structures, and the anti-pullout pile facility has multiple groups of the linkage structures, which are symmetrically arranged around the central axis of the anti-pullout pile.

[0022] Preferably, the compression degree of the spring can ensure that sufficient elastic force is generated to push the telescopic member out, and a limiting device is installed on the anti-pullout member to ensure that a part of the telescopic member will remain in the launching tube.

[0023] Preferably, a hole is left on the outer cylinder to allow the baffle to move up and down.

[0024] Preferably, the outer surface of the outer tube is in contact with the baffle.

[0025] Preferably, the friction between the pull-out pile and the soil, the bonding force brought by the pull-out member inserted into the soil layer, and the pressure generated by the soil on the pull-out angle together constitute the soil pull-out effect. The ultimate pull-out force can be calculated by formula (6):

[0026]

[0027] Where: Q ult A is the ultimate pull-out bearing capacity of the pile; p is the end area of ​​the pile; A s is the lateral area of ​​the pile; f is the pull-out strength of the soil; α is the length effect correction coefficient of the pile, which depends on the aspect ratio of the pile and the type of stratum; β is the acceleration coefficient of the soil, which depends on the seismic action; P is the soil pressure; A1 is the force-bearing area of ​​the telescopic member; A2 is the force-bearing area of ​​the pull-out angle.

[0028] Compared with the prior art, the present invention has the following benefits:

[0029] (1) The pull-out pile of the present invention is driven in the same way as ordinary pile foundations, and no special construction requirements are required. When the pull-out effect is played after being driven in, the pull-out angle of the internal pull-out member can be rotated upward when it is inserted into the soil, reducing the force-bearing area during insertion; when the pull-out effect is played, the pull-out angle will be rotated downward by the effect of the soil to play the pull-out effect, and the baffle is moved upward by the connecting member, so that the telescopic member of the external pull-out member is extended outward, playing a double pull-out effect, and the linkage mechanism saves manpower on the operation of the machine.

[0030] (2) The hollow annular structure formed by the inner tube and the outer tube of the present invention has a smaller force-bearing surface area during the process of being driven into the soil, making it easier to drive into the soil and saving materials. An internal anti-pullout member is fixed on the inner surface of the inner tube, and the interior is through-connected from top to bottom. The internal anti-pullout member can play an anti-pullout role in the internal soil force and reduce resistance during driving into the soil, which is conducive to the simplicity of construction.

[0031] (3) The pull-out structure of the pull-out pile of the present invention is automatically unfolded by utilizing the effect of soil without any artificial external force, and its good integrity also greatly enhances its practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a cross-section of an offshore wind turbine pullout pile.

[0033] Figure 2 This is a cross-sectional view of the offshore wind turbine pullout piles when unfolded.

[0034] Figure 3 This is a bottom view of the offshore wind pullout pile.

[0035] Figure 4 It is the rotating shaft of the offshore wind turbine pullout pile.

[0036] In the figure: 1, inner tube, 2, outer tube, 3, baffle, 4, connection structure 2, 5, connecting rod, 6, connection structure 1, 7, outer rotating shaft, 8, inner rotating shaft, 9, anti-pullout angle, 10, anti-pullout member, 11, launching tube, 12, limiting device, 13, spring, 14, internal hollow bottom inward-retracting ring structure. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with specific embodiments. The following embodiments provide specific structures and size standards, which will help technicians further understand the specific structure of the present invention. Without departing from the basic structure of the present invention, the size of the present invention can also be appropriately adjusted, all of which belong to the protection scope of the present invention.

[0038] The construction of the present invention comprises the following steps: after the anti-pullout piles are welded and assembled with the anti-pullout parts, they are transported to a designated location for construction; before piling, it is ensured that the anti-pullout parts are in a contracted state, the pile body is tightly fitted, and the integrity is good; the piling construction is carried out in the same manner as the conventional pile construction method; after the piling is completed, the construction is ended, and the internal anti-pullout parts and the external anti-pullout parts will automatically function under the action of the soil.

[0039] Figure 1 2 is a cross-sectional view of an offshore wind power pull-out pile according to a preferred embodiment of the present invention. Figure 1 As shown, an offshore wind power pull-out pile of a preferred embodiment of the present invention comprises an outer tube 2 and an inner tube 1. Both the outer tube 2 and the inner tube 1 are hollow tubular structures that penetrate from top to bottom. The outer tube 2 is sleeved on the outer side of the inner tube 1. The middle area of ​​the outer tube 2 and the inner tube 1 forms a closed structure at the bottom, and the inner tube 2 and the outer tube 1 are fixedly connected.

[0040] The internal anti-pulling member includes an anti-pulling angle 9 and an inner rotating shaft 8; the inner rotating shaft 8 is fixedly mounted on the inner wall of the inner tube 1; the anti-pulling angle 9 is a triangular structure, one side of the triangular structure is connected to the inner rotating shaft 8 so that the anti-pulling angle 9 can rotate upward around the connection point between the inner rotating shaft 8 and the inner tube until the anti-pulling angle 9 contacts the inner wall of the inner tube 1. When the anti-pulling angle 9 plays an anti-pulling role, it will be affected by the force of the soil and expand downward. The upper and lower parts are both the orientation determination of the anti-pulling pile in the working state. The expansion length of the anti-pulling angle 9 is determined by formula (1):

[0041]

[0042] Where: l0 is the length of the oblique section of the pull-out angle, θ is the rotation angle of the pull-out angle, and r is the radius of the rotation axis.

[0043] In a preferred embodiment, the length of the oblique section of the anti-pulling angle l0 is 1.2m, the rotation angle θ of the anti-pulling angle is 80 degrees, and the radius r of the rotation axis is 0.1m, so the unfolded length is 1.18m.

[0044] The external anti-pullout member includes a telescopic member 10, a spring 13, a launch tube 11 and a baffle 3; the bottom of the launch tube 11 is connected to the outer wall of the inner tube 1, and the launch tube hole is connected to the outer tube 2; the tube wall of the outer tube 2 is provided with an opening penetrating the tube wall of the outer tube at a position coincident with the hole of the launch tube 11;

[0045] During the process of driving the anti-pullout pile into the soil, the baffle blocks the telescopic member 10 in the launching tube 11 by blocking the hole of the launching tube. At this time, the spring is located at the bottom of the launching tube 11 and is in a compressed state.

[0046] The connecting member includes an outer rotating shaft 7, a connecting rod 5, a connecting structure 1 6 and a connecting structure 2 4, and an inner rotating shaft 8, an outer rotating shaft 7, a connecting structure 1 6, a connecting rod 5, a connecting structure 2 4 and a baffle 3 are connected in sequence; wherein the inner rotating shaft 8 and the outer rotating shaft 7 rotate synchronously and in opposite directions and at the same rotation angle; the connecting structure 2 4 is located below the connecting structure 1 6;

[0047] When the pull-out pile is subjected to a pulling force, the pull-out angle 9 is subjected to the force of the soil and expands downward, driving the inner rotating shaft 8 to rotate downward, and then driving the outer rotating shaft 7 to rotate upward, and then driving the baffle 3 to move upward through the connecting structure 1 6, the connecting rod 5, and the connecting structure 2 4, releasing the telescopic part 10 in the launching tube 11 into the soil.

[0048] Reference Figure 2As shown, an offshore wind power pull-out pile of a preferred embodiment of the present invention is a schematic diagram of a group of pull-out parts fully unfolded, and the external pull-out parts and the internal pull-out parts form a group of linkage structures. The pull-out pile facility has multiple groups of the linkage structures, which are symmetrically arranged around the central axis of the pull-out pile at equal intervals, so that the interaction force of the soil body when the pull-out pile is played is symmetrically distributed along the pull-out pile. In addition, the number of pull-out parts on each column can be appropriately adjusted according to the length of the pile. In this embodiment, the number of pull-out parts is 36, that is, 6 groups, including six columns, 6 in each column, and the connecting line of two in each group intersects with the central axis. The internal pull-out parts are fixed on the inner surface of the inner tube 1, and the interior is through from top to bottom. The internal pull-out parts can play a pull-out role in the internal soil force, and at the same time, they can reduce resistance when driven in, which is conducive to the simple construction. When the internal pull-out parts are inserted into the soil, the pull-out angle 9 of the pull-out parts can be rotated upward, which mainly plays the role of the internal pull-out component and reduces the force area during insertion. At the same time, the inner rotating shaft 8 is provided with a limited structure to control the rotation angle. When the pull-out effect is played, the pull-out angle 9 is forced to move downward, driving the inner rotating shaft 8 to rotate downward. At the same time, the inner rotating shaft 8 drives the outer rotating shaft 7, the connecting structure 1 6 and then drives the connecting rod 5 to move. The connecting rod 5 drives the baffle 3 to move up to the limit position through the connecting structure 2 4. The spring 13 ejects the pull-out member 10 through the inner firing tube 11. The upper limit device 12 of the cylinder controls the ejection length. The two are in a linkage mechanism. The lower part of the outer cylinder 2 is an inner hollow bottom inward ring structure 14. The outer surface is tightly fitted with the baffle 3. It has a smaller force-bearing surface area during the process of driving into the soil, which is easier to drive in. At the same time, it can save materials and make the pull-out pile have better pull-out bearing capacity while taking into account the integrity.

[0049] Figure 3 This is a top view of an offshore wind power pull-out pile of a preferred embodiment of the present invention, in which the inner tube 2 is of a through type, which reduces the contact area when driving into the soil, thereby reducing resistance and making construction easier. The pile end is an internal hollow bottom inward-retracted annular pile head structure. The baffle 3 fits the outer wall of the outer tube 2 on the outside, and the baffle completely blocks the launch tube when driven in. The elastic force provided by the spring is determined by formula (2), the accommodating volume of the launch tube is determined by formula (3), and the telescopic part is a large-volume steel needle, and its volume is mainly determined by formula (4);

[0050]

[0051] In the formula: k is the elastic coefficient of the spring, x is the deformation of the spring, R is the inner tube radius, r1 is the cross-sectional radius of the launching tube, r2 is the cross-sectional radius of the telescopic part, h2 is the length of the cylindrical part of the telescopic part, and h3 is the length of the conical part of the telescopic part.

[0052] In a preferred embodiment, the elastic coefficient k of the spring is 2.5 N / mm, the deformation x of the spring is 214 mm, the inner tube radius R is 3 m, the cross-sectional radius r1 of the launch tube is 1.6 m, the cross-sectional radius r2 of the telescopic member is 1.5 m, the length h2 of the cylindrical part of the telescopic member is 2 m, and the length h3 of the conical part of the telescopic member is 0.6 m; therefore, the elastic force provided by the spring is 535.7 N, and the accommodating volume of the launch tube is 24.13 m 3 , the volume of the telescopic part is 15.55m 3 .

[0053] Figure 4 It is a schematic diagram of the rotating shaft of an offshore wind power pull-out pile of a preferred embodiment of the present invention, and the rotating shaft is a double-layer type. A limiting device 12 is arranged on the inner wall of the inner tube 1, which can control the rotation angle of the pull-out angle 9 when it is driven in, and can also control the rotation angle of the pull-out angle 9 when subjected to pull-out force. The baffle 3 is opened by the transmission structure and the opening size is sufficient to release the telescopic member (10). The displacement size of the baffle 3 is determined by formula (5). The friction between the pull-out pile and the soil, the bonding force brought by the pull-out member inserted into the soil layer, and the pressure generated by the soil on the pull-out angle 9 together constitute the soil pull-out effect. The ultimate pull-out force can be calculated by formula (6):

[0054] L=l1×cosθ1 (5)

[0055]

[0056] Where: l1 is the length of the connecting rod, θ1 is the rotation angle of the connecting rod 5. ult A is the ultimate pull-out bearing capacity of the pile; p is the end area of ​​the pile; A s is the lateral area of ​​the pile; f is the pull-out strength of the soil; α is the length effect correction coefficient of the pile, which depends on the aspect ratio of the pile and the type of stratum; β is the acceleration coefficient of the soil, which depends on the seismic action; P is the soil pressure; A1 is the force-bearing area of ​​the telescopic member; A2 is the force-bearing area of ​​the pull-out angle.

[0057] In a preferred embodiment, the length l1 of the connecting rod is 1.6 m, the rotation angle θ1 of the connecting rod 5 is 20 degrees, and the end area A of the pile is p 113.1m 2 , the lateral area of ​​the pile A s 5937.6m 2 , the tensile strength f of the soil is 10 kPa, the length effect correction coefficient α of the pile is 0.9, the acceleration coefficient β of the soil is 0.1 g, and the force area A1 of the telescopic member is 8.5 m 2 , the force bearing area A2 of the anti-uplift angle is 1.2m 2, so the maximum displacement distance of the baffle is 1.5m, and the ultimate pull-out force of this pile is 6056.8kN.

Claims

1. A pull-out pile, characterized in that: The pull-out pile comprises a two-layer cylindrical structure, an internal pull-out member, an external pull-out member and a connecting member, wherein: The two-layer cylinder structure comprises an outer cylinder (2) and an inner cylinder (1); the outer cylinder (2) and the inner cylinder (1) are both hollow tubular structures that penetrate from top to bottom; the outer cylinder (2) is sleeved on the outer side of the inner cylinder (1); the inner cylinder (2) and the outer cylinder (1) are fixedly connected; The internal anti-pulling member comprises an anti-pulling angle (9) and an inner rotating shaft (8); the inner rotating shaft (8) is fixedly mounted on the inner wall of the inner tube (1); one side of the anti-pulling angle (9) is connected to the inner rotating shaft (8) so that the anti-pulling angle (9) can rotate upward around the connection point between the inner rotating shaft (8) and the inner tube until the anti-pulling angle (9) contacts the inner wall of the inner tube (1), and the anti-pulling angle (9) will be expanded downward under the action of the soil when it plays an anti-pulling role, and the upper and lower sides are determined by the direction of the anti-pulling pile along the wall of the outer tube when it is working; The external anti-pullout component comprises a telescopic component (10), a spring (13), a launch tube (11) and a baffle (3); the bottom of the launch tube (11) is connected to the outer wall of the inner tube (1), and the launch tube opening is connected to the outer tube (2); the tube wall of the outer tube (2) is provided with an opening penetrating the tube wall of the outer tube at a position overlapping with the opening of the launch tube (11); During the process of driving the anti-pullout pile into the soil, the baffle blocks the telescopic member (10) in the launching tube (11) by blocking the hole of the launching tube, and at this time, the spring is located at the bottom of the launching tube (11) and is in a compressed state; When the anti-pulling pile is subjected to a pulling force, the anti-pulling angle (9) is subjected to the force of the soil and expands downward, driving the baffle (3) to move upward through the connecting member, thereby releasing the telescopic member (10) in the launching tube (11) into the soil.

2. The pull-out pile according to claim 1, characterized in that: The anti-pulling angle (9) is a triangular structure, and the unfolded length of the anti-pulling angle (9) is determined by formula (1): Where: l0 is the length of the oblique section of the pull-out angle, θ is the rotation angle of the pull-out angle, and r is the radius of the rotation axis.

3. The pull-out pile according to claim 1, characterized in that: The connecting member comprises an outer rotating shaft (7), a connecting rod (5), a connecting structure 1 (6) and a connecting structure 2 (4); an inner rotating shaft (8), an outer rotating shaft (7), a connecting structure 1 (6), a connecting rod (5), a connecting structure 2 (4) and a baffle (3) are connected in sequence; wherein the inner rotating shaft (8) and the outer rotating shaft (7) rotate synchronously and in opposite directions but at the same rotation angle; and the connecting structure 2 (4) is located below the connecting structure 1 (6); When the anti-pulling pile is subjected to a pulling force, the anti-pulling angle (9) is subjected to the force of the soil and expands downward, driving the inner rotating shaft (8) to rotate downward, thereby driving the outer rotating shaft (7) to rotate upward, and then driving the baffle (3) to move upward through the connecting structure (6), the connecting rod (5), and the connecting structure (4), thereby releasing the telescopic member (10) in the launching tube (11) into the soil.

4. The pull-out pile according to claim 1, characterized in that: The elastic force provided by the spring is determined by formula (2), the volume of the launch tube is determined by formula (3), the baffle is tightly fitted to the outer wall of the outer tube, the telescopic member is a large steel needle, and its volume is determined by formula (4); the displacement of the baffle (3) is determined by formula (5); L=l1×cosθ1 (5) Where: k is the elastic coefficient of the spring, x is the deformation of the spring, R is the inner tube radius, r1 is the cross-sectional radius of the launch tube, r2 is the cross-sectional radius of the telescopic member, h2 is the length of the cylindrical part of the telescopic member, h3 is the length of the conical part of the telescopic member; l1 is the length of the rod of the connecting member, and θ1 is the rotation angle of the connecting rod (5).

5. The pull-out pile according to claim 1, characterized in that: The external anti-pullout parts and the internal anti-pullout parts form a group of linkage structures. The anti-pullout pile facility has multiple groups of the linkage structures, which are symmetrically arranged around the central axis of the anti-pullout pile.

6. The pull-out pile according to claim 1, characterized in that: The compression degree of the spring can ensure that sufficient elastic force is generated to push the telescopic member out, and a limiting device (12) is installed on the anti-pullout member to ensure that a part of the telescopic member (10) is retained in the launching tube (11).

7. The pull-out pile according to claim 1, characterized in that: A hole is left on the outer cylinder to enable the baffle (3) to move up and down.

8. The pull-out pile according to claim 1, characterized in that: The outer surface of the outer tube (2) is in contact with the baffle (3).

9. The pull-out pile according to claim 1, characterized in that: The friction between the pull-out pile and the soil, the bonding force brought by the pull-out member inserted into the soil layer, and the pressure generated by the soil at the pull-out angle (9) together constitute the soil pull-out effect. The ultimate pull-out force can be calculated by formula (6): Where: Q ult A is the ultimate pull-out bearing capacity of the pile; p is the end area of ​​the pile; A s is the lateral area of ​​the pile; f is the pull-out strength of the soil; α is the length effect correction coefficient of the pile, which depends on the aspect ratio of the pile and the type of stratum; β is the acceleration coefficient of the soil, which depends on the seismic action; P is the soil pressure; A1 is the force-bearing area of ​​the telescopic member; A2 is the force-bearing area of ​​the pull-out angle.

10. Use of the pull-out pile according to any one of claims 1 to 9 in soil pull-out resistance.

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