Screw pile

Abstract

The invention relates to a screw pile, comprising an outer pile body and a pile core, wherein: the outer pile body comprises a first pile body made of engineering plastic, the first pile body comprises a shell with an opening at one end and a threaded structure, the shell and the opening are opposite to each other to form a tapered portion, and the threaded structure is arranged on the outer surface of the shell; the pile core is arranged in the shell and is anchored and connected to the shell by at least one fastener, so that the pile core and the outer pile body are fixed as a whole, so that the outer pile body and the pile core are effectively combined, and the screw pile can be embedded into the soil by rotating it clockwise, and the threaded structure is in close contact with the soil and is restricted by the soil to form a large up and down resistance, which is transmitted to the pile core through the fastener to gather into a large pull-out resistance, and the soil and water quality will not be polluted during the screwing process, and the stability is good, and the first pile body isolates the pile core and the soil; the screw pile can be completely withdrawn from the soil by rotating it counterclockwise, which is convenient to take out, and there will be no residue in the soil, and the environmental protection performance is good.

Description

Technical Field

[0001] The invention relates to the technical field of foundation engineering, in particular to a screw pile. Background Art

[0002] In the field of foundation engineering technology, pull-out resistance is an important indicator to measure the performance of various structural foundations. Concrete foundations rely on their own gravity to resist pull-out forces and can change the pull-out resistance by controlling the amount of concrete. Therefore, they are widely used in agricultural facilities, photovoltaic power generation, power and communication towers, and municipal engineering.

[0003] With the development of foundation engineering, the traditional concrete foundation can no longer meet the cost requirements of users for structural foundations by increasing the amount of concrete to improve the pull-out force. In order to reduce the production cost while ensuring the pull-out force, the following three solutions are currently adopted: Method 1: Prefabricated concrete pipe piles, the concrete foundation is set in the pipe piles, and the friction between the surface of the pipe piles and the soil is increased by increasing the length of the pipe piles in the soil or thickening the pile body to improve the pull-out force. However, heavy equipment is required to embed the pipe piles into the soil during construction, which is inconvenient to install; Method 2: Prefabricated concrete pipe piles are added with threads on the surface to improve the pull-out force through the resistance of the threads, but this method can only set plain concrete at the tip of the threads, which has no bearing capacity, and requires high-power mechanical equipment to complete the screwing of the pipe piles, which is costly; Method 3: Steel spiral piles, which achieve pull-out resistance through the resistance formed by the large blades at the bottom, but the corrosion of steel limits the scope of use of steel spiral piles, and the anti-corrosion layer (galvanized, spray-painted, etc.) on the surface is easily scratched when screwed in, making the anti-corrosion effect poor. In addition, the large excavation construction of the above-mentioned concrete foundation and the unique alkalinity of concrete cause serious damage to the soil and are difficult to remove. The remaining part below the surface seriously affects the soil environment and land cultivation, which is not conducive to environmental and soil protection.

[0004] Therefore, it is particularly important to provide a concrete structure with greater pull-out resistance and less impact on the soil. Summary of the invention

[0005] Based on this, it is necessary to provide a screw pile to address the above problems. The screw pile has less impact on the soil, has better environmental protection performance, has greater pull-out resistance, and has a higher product mass production yield.

[0006] A screw pile comprises an outer pile body and a pile core, wherein:

[0007] The outer pile body comprises a first pile body made of engineering plastic, the first pile body comprises a shell and a thread structure, one end of the shell is open and the other end forms a tapered portion, and the thread structure is arranged on the outer surface of the shell;

[0008] The pile core is arranged in the shell and is anchored and connected to the shell through at least one fastener.

[0009] The screw pile is connected to the shell by fasteners through anchoring, so as to fix the pile core and the outer pile body as one, so that the outer pile body and the pile core are effectively combined. The screw pile can be embedded into the soil by rotating it clockwise, and the threaded structure extending into the soil is in close contact with the soil and is restricted by the soil to form a large up and down resistance, which is transmitted to the pile core through the fasteners to converge into a large pull-out resistance, which is greatly improved compared with the traditional gravity concrete foundation; and the first pile body made of engineering plastic has the characteristics of strong wear resistance, high strength, stable chemical properties, strong anti-aging performance, etc., and will not pollute the soil and water quality during the screwing process, and has good stability. In addition, the first pile body isolates the pile core and the soil, and has little impact on the soil; the screw pile can be completely withdrawn from the soil by rotating it counterclockwise, which is convenient to remove, and there will be no residue in the soil, which has less pollution to the soil and water, and has good environmental performance.

[0010] In one embodiment, the pile core is reinforced concrete, including concrete and a steel cage, the steel cage is arranged in the shell, the concrete is poured into the shell and the steel cage is fixed to the shell. The pile core has various structural forms and structures, and reinforced concrete can be used. When it is specifically set up, the steel cage is placed in the shell, and then concrete is poured into the shell. The concrete is cured to fix the steel cage in the shell, forming a screw pile that is easy to carry.

[0011] In one embodiment, the fastener is a plastic-sealed steel bar, which has a plastic-coated end. The shell is provided with a through hole that penetrates the wall thickness thereof, the through hole is located between two adjacent teeth of the spiral structure, the plastic-coated end of the plastic-sealed steel bar is embedded in the through hole, and the end of the plastic-sealed steel bar away from the plastic-coated end protrudes from the through hole and is fixed in the concrete. The shell and the reinforced concrete are anchored and connected by the plastic-sealed steel bar, and the plastic-coated end of the plastic-sealed steel bar head is embedded in the through hole of the shell to isolate the soil and the reinforced concrete together with the shell to avoid affecting the soil.

[0012] In one embodiment, a conductive column is provided on the inner wall of the shell, the conductive column is coaxially arranged with the through hole, the plastic-sealed steel bar passes through the conductive column, and the end away from the plastic-coated end protrudes from the end face of the conductive column. The conductive column is provided to increase the contact area between the plastic-sealed steel bar and the shell, improve the anchoring strength between the shell and reinforced concrete, and better achieve the combination between the outer pile body and reinforced concrete.

[0013] In one embodiment, the outer pile body includes a second pile body, and the second pile body is a plastic sleeve with two ends opened, and the plastic sleeve is sleeved on the outside of the pile core. The plastic sleeve isolates reinforced concrete and soil to avoid affecting the soil, while reducing the use of engineering plastics and reducing production costs.

[0014] In one embodiment, the plastic sleeve is inserted into the housing and fixed to the housing by screws. In a specific configuration, the plastic sleeve and the housing can be fixed as one and then the concrete is poured.

[0015] In one embodiment, the pile core further comprises a chuck, the steel cage passes through the chuck, the chuck has a bearing surface, the plastic sleeve is sleeved on the outside of the pile core and located on the bearing surface, and the end of the steel cage away from the bearing surface is inserted into the shell. The pile core has various structural forms and structures, and reinforced concrete with a chuck can be used to adapt to the underwater mud layer. The plastic sleeve isolates the water from the reinforced concrete. The screw pile at the bottom of the chuck is screwed into the mud. The shell isolates the mud and the reinforced concrete. The threaded structure extends into the mud and is restricted by the mud to form a larger upper and lower resistance. The resistance is transmitted to the reinforced concrete through the plastic head steel bar to gather into a larger pull-out resistance.

[0016] In one embodiment, the pile core is a square steel tube, the fastener includes two plastic fixing disks, the square steel tube is embedded in the two plastic fixing disks, and is fixedly connected to the shell body by stainless steel screws. The pile core has various structural forms, and a square steel tube can be used. The shell body and the plastic fixing disk can be fixedly connected by stainless steel screws, and the two plastic fixing disks fix the square steel tube embedded therein to the shell body, so that the pile core and the outer pile body are effectively combined.

[0017] In one embodiment, the thread structure has a constant pitch, and the major diameter of the thread structure gradually increases in a direction away from the tapered portion to form a "self-tapping screw" effect, thereby reducing the pressure dependence on the rotating construction machinery.

[0018] In one of the embodiments, a thin-walled metal cone head is sleeved on the outer side of the conical portion to displace small gravels and reduce the impact of small gravels in the soil on the screw piles. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A structural schematic diagram of a screw pile provided by the present invention;

[0020] Figure 2 for Figure 1 A cross-sectional view of the anchor connection position between the middle shell and the pile core;

[0021] Figure 3Another structural schematic diagram of a screw pile provided by the present invention;

[0022] Figure 4 for Figure 3 A cross-sectional view of the anchor connection position between the middle shell and the pile core;

[0023] Figure 5 Another structural schematic diagram of a screw pile provided by the present invention;

[0024] Figure 6 for Figure 5 Exploded view of the anchor connection between the middle shell and the pile core. DETAILED DESCRIPTION

[0025] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] The technical solution provided by the embodiments of the present invention is described below in conjunction with the accompanying drawings.

[0027] like Figure 1 as well as Figure 2 As shown, a screw pile is used for soil foundation treatment, comprising an outer pile body 100, a pile core 200 and a fastener 300, wherein:

[0028] The outer pile body 100 at least includes a first pile body 110, and the first pile body 110 is made of engineering plastics. There are many options for engineering plastics, such as PP (polymer polypropylene), PE (polyethylene), PVC (polyvinyl chloride), ABS (acrylonitrile butadiene styrene), and glass fiber reinforced plastics. During the specific setting, according to the mechanical properties and corresponding costs of various materials, the first pile body 110 is made of polymer polypropylene plus glass fiber.

[0029] The first pile body 110 includes a shell 111 and a threaded structure 112. One end of the shell 111 is open, and a tapered portion 113 is formed at the position of the other end opposite to the opening. The threaded structure 112 is arranged on the outer surface of the shell 111. The shell 111 and the threaded structure 112 can be molded at one time by mold injection molding. In specific settings, the length of the first pile body 110 is designed according to the force requirements and determined during the mold making process. The first pile body 110 can also be made in sections and connected during the assembly process. When connecting, pay attention to the continuity of the threaded structure 112 and the change in the diameter of the pipe embedded in the connection part. The wall thickness and thread height of the outer pile body 100 are designed according to the selected material and force requirements. In specific settings, the length of the thread can be 30mm-50mm;

[0030] The pile core 200 is disposed in the housing 111 and is anchored to the housing 111 via at least one fastener 300 .

[0031] The screw pile is connected to the pile core 200 and the shell 111 by the fastener 300, so that the pile core 200 and the outer pile body 100 are fixed as one, so that the outer pile body 100 and the pile core 200 are effectively combined. The screw pile can be embedded into the soil by rotating it clockwise, and the threaded structure 112 extending into the soil is in close contact with the soil and is restricted by the soil to form a large up and down resistance, which is transmitted to the pile core 200 through the fastener 300 to gather into a large pull-out resistance, which is greatly improved compared with the traditional gravity concrete foundation; and the first pile body 110 made of engineering plastic has the characteristics of strong wear resistance, high strength, stable chemical properties, strong anti-aging performance, etc., and will not pollute the soil and water quality during the screwing process, and has good stability, and the first pile body 110 isolates the pile core 200 and the soil, and has little impact on the soil; the screw pile can be completely withdrawn from the soil by rotating it counterclockwise, which is convenient to take out, and there will be no residue in the soil, which has less pollution to the soil and water, and has good environmental performance.

[0032] The pile core 200 has various structural forms. In a preferred embodiment, Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, the pile core 200 is reinforced concrete 210 , including concrete 211 and a steel cage 212 . The steel cage 212 is disposed in the shell 111 . The concrete 211 is poured into the shell 111 and the steel cage 212 is fixed to the shell 111 .

[0033] The screw pile, the reinforced concrete 210 has strong tensile, compressive, torsion and shear resistance. The screw pile made of the reinforced concrete 210 as the pile core 200 has strong bearing capacity, pull-out resistance, horizontal force resistance, small deformation, good stability, simple and rapid construction, and low cost. When specifically set, the steel cage 212 is placed in the shell 111, and then the concrete 211 is poured into the shell 111. The concrete 211 is solidified to fix the steel cage 212 in the shell 111, forming a screw pile that is easy to carry. The steel cage 212 includes three or more vertical steel bars as main load-bearing steel bars. The extension direction of these vertical steel bars is parallel to the axial direction of the shell 111. According to the stress requirements, the vertical steel bars can be made of Φ16-Φ22 steel bars; the steel cage 212 also includes multiple horizontal reinforcements as auxiliary reinforcements arranged on the outside of the vertical steel bars. According to the stress requirements, the horizontal reinforcements can be made of Φ10-Φ16 steel bars; the strength grade of the concrete 211 is not less than C30, and the strength grade of the concrete 211 and the specific structure of the steel cage 212 are selected according to the actual situation of the screw pile and its application environment.

[0034] The fastener 300 has various structural forms, specifically, Figure 2as well as Figure 4 As shown, the fastener 300 is a plastic-sealed steel bar 310, which has a plastic-coated end. A through hole penetrating the wall thickness of the shell 111 is provided, and the through hole is located between two adjacent teeth of the spiral structure. The plastic-coated end of the plastic-sealed steel bar 310 is embedded in the through hole, and the end of the plastic-sealed steel bar 310 away from the plastic-coated end protrudes through the through hole and is fixed in the concrete 211.

[0035] The above-mentioned screw pile anchors the shell 111 and the reinforced concrete 210 through at least one plastic-sealed steel bar 310 to transmit the resistance formed by the threaded structure 112 to the reinforced concrete 210. In the specific setting, the number of plastic-sealed steel bars 310 can be multiple, and the multiple plastic-sealed steel bars 310 are evenly distributed along the extension direction of the shell 111 and evenly distributed along the circumference of the shell 111 to better anchor the shell 111 and the reinforced concrete 210, so that the shell 111 and the reinforced concrete 210 are effectively combined, so that the resistance formed by the threaded structure 112 is dispersed and transmitted to the reinforced concrete 210.

[0036] During molding, first, a through hole is drilled at the corresponding position of the shell 111 according to the diameter of the plastic-sealed steel bar to be embedded, the through hole is located between two adjacent teeth of the spiral structure, and two to three exhaust holes are drilled on the tube wall of the shell 111 near the tapered portion 113; then the tied steel cage 212 is inserted into the outer pile body 100 until the bottom of the shell 111, and then the plastic-sealed head steel bar 310 is inserted from the through hole, and the end of the plastic-sealed head steel bar 310 away from the plastic-coated end protrudes from the through hole. At this time, the plastic-coated end of the plastic-sealed head steel bar 310 is embedded in the through hole to fit tightly with the through hole, and in order to ensure the tightness of the fit, glue can also be applied to the plastic-coated end to ensure that the plastic-coated end of the plastic-sealed steel bar head is embedded in The through hole of the shell 111 is used to isolate the soil and reinforced concrete 210 together with the shell 111 to avoid affecting the soil; then the concrete 211 with a strength not less than C30 is poured into the outer pile body 100, and in order to ensure the pouring quality, the outer pile body 100 must be kept vertical, and at the same time, it must be vibrated or shaken, which requires simple tooling; finally, the finished product after pouring needs to be kept vertically upright for 24 hours before it can be moved, and can be shipped from the factory after 7 days. At this time, the steel cage 212 and the plastic-sealed head steel bars 310 are fixed in the shell 111 by the concrete 211, so that the pile core 200 and the outer shell 111 are anchored and connected by the plastic-sealed head steel bars 310.

[0037] It is worth noting that the above screw piles are lower in cost than the original concrete foundation, and the construction is simple and fast, reducing the total cost by about 15%-20%. Especially when the construction conditions are limited, the use of small (single pile weight less than 100KG) pile groups can be transported by manpower and portable simple machinery can be used, which has significant cost advantages. In addition, there is no need for on-site steel bar binding and concrete 211 maintenance, nor is there any need for heavy machinery to enter and exit the site. The construction can be completed quickly and the next step can be entered. The construction period is short, and the effect is particularly obvious for winter construction in northern regions or projects that need to rush the construction period.

[0038] In order to improve the anchoring strength between the shell 111 and the reinforced concrete 210, the contact area between the plastic-sealed steel bar 310 and the shell 111 can be ensured by ensuring the wall thickness of the shell 111. In order to improve the contact area between the plastic-sealed steel bar 310 and the shell 111, more specifically, Figure 2 As shown, a conductive column 114 is provided on the inner wall of the shell 111. In the specific setting, the conductive column 114 and the shell 111 are integrally formed, the conductive column 114 is coaxially arranged with the through hole, the plastic-sealed head steel bar 310 passes through the conductive column 114, and the end away from the plastic-coated end protrudes from the end face of the conductive column 114.

[0039] In the screw pile, the contact area between the plastic-sealed steel bar 310 and the housing 111 includes the inner wall of the through hole and part of the inner surface of the conductive column 114. Compared with only setting the through hole, the contact area between the plastic-sealed steel bar 310 and the housing 111 can be increased by setting the conductive column 114, the anchoring strength between the housing 111 and the reinforced concrete 210 can be improved, and the combination between the outer pile body 100 and the reinforced concrete 210 can be better achieved. At this time, the pipe wall thickness of the housing 111 can be greatly reduced, and the production cost can be reduced. In the specific setting, the conductive column 114 corresponds to the plastic-sealed steel bar 310 one by one, and the conductive column 114 is evenly distributed along the circumference of the housing 111 and evenly distributed along the axial direction of the housing 111. The number, diameter, and wall thickness of the conductive column 114 can be designed according to the actual situation of the plastic-sealed steel bar 310.

[0040] In order to better isolate the reinforced concrete 210 and the soil, specifically, as Figure 1 as well as Figure 3 As shown, the outer pile body 100 includes a second pile body 120 . The second pile body 120 is a plastic sleeve with openings at both ends. The plastic sleeve is sleeved on the outer side of the pile core 200 .

[0041] The screw pile is a void load area because the soil surface is relatively loose. The upper part of the outer pile body 100 is made of a plastic sleeve made of ordinary plastic to reduce the material of engineering plastics and reduce production costs. The plastic sleeve plays a shaping role on the concrete 211 during the molding process, reduces friction resistance during the screw pile screwing in and out, and isolates the concrete 211 from the soil when the screw pile is inserted into the soil to avoid affecting the soil. In the specific setting, the plastic sleeve is formed in one step by drawing or injection molding, and the specific wall thickness of the plastic sleeve is selected according to the actual situation of the screw pile and its application environment.

[0042] More specifically, the plastic sleeve is inserted into the housing 111 and fixed to the housing 111 by screws.

[0043] When the screw pile is specifically set up, the plastic sleeve and the shell 111 can be fixed together before pouring the concrete 211. First, the shell 111 produced in sections is fixedly connected, and the fixing connection method can be gluing or other fixing methods; then the upper plastic sleeve is inserted into the shell 111 and fixedly connected, and the fixing connection method can be screw connection or other fixing methods, and then the tied steel cage 212 is inserted from the upper plastic sleeve until the bottom of the shell 111; then the plastic-sealed head steel bar 310 is embedded in the through hole; finally, the concrete 211 is poured.

[0044] The pile core 200 has various structural forms. In a preferred embodiment, Figure 3 As shown, the pile core 200 also includes a chuck 213, the steel cage 212 passes through the chuck 213, the chuck 213 has a bearing surface, the plastic sleeve is sleeved on the outside of the pile core 200 and located on the bearing surface, and the end of the steel cage 212 away from the bearing surface is inserted into the shell 111.

[0045] In order to adapt to the underwater silt layer, the pile core 200 of the screw pile can be a reinforced concrete 210 with a chuck 213. The chuck 213 can be a concrete 211 disc structure or other structural forms. The chuck 213 bears part of the water pressure to enhance the pull-out resistance. In the specific setting, the plastic sleeve is sleeved on the outside of the pile core 200 and is located on the bearing surface. The end of the steel cage 212 away from the bearing surface is inserted into the shell 111. The plastic sleeve isolates water from the reinforced concrete 210. The screw pile under the chuck 213 is screwed into the silt. The shell 111 isolates the silt and the reinforced concrete 210. The threaded structure 112 extends into the silt and is restricted by the silt to form a larger upper and lower resistance. The resistance is transmitted to the reinforced concrete 210 through the plastic-sealed steel bar 310 to converge into a larger pull-out resistance, so that the pull-out resistance of the screw pile is larger, the impact on soil and water quality is smaller, and the environmental protection performance is better.

[0046] The pile core 200 has various structural forms. In a preferred embodiment, Figure 5 as well as Figure 6 As shown, the pile core 200 is a square steel tube 220 , and the fastener 300 includes two plastic fixing plates 320 . The square steel tube 220 is embedded in the two plastic fixing plates 320 and is fixedly connected to the housing 111 by stainless steel screws 330 .

[0047] The screw pile, in order to adapt to the soil foundation or simple basic engineering that is easy to handle, such as loose soil, temporary short-term piling, the pile core 200 can be a square steel pipe 220, which is light and easy to carry. When specifically set, a square hole that matches the square steel pipe 220 is set on the plastic fixing plate 320, and the plastic fixing plate 320 is set in the housing 111. The square steel pipe 220 is embedded in the square holes of the two plastic fixing plates 320. The housing 111 and the plastic fixing plates 320 can be fixedly connected by stainless steel screws 330, and the two plastic fixing plates 320 fix the square steel pipe 220 embedded therein to the housing 111, so that the pile core 200 and the outer pile body 100 are effectively combined. And in order to facilitate screwing in and out, a pressure plate is set at one end of the square steel pipe 220 away from the plastic fixing plate 320 for user operation.

[0048] In order to facilitate screwing in and out of the screw pile, in a preferred embodiment, the thread structure 112 has a constant pitch, and the major diameter of the thread structure 112 gradually increases in a direction away from the tapered portion 113 .

[0049] The screw pile is configured with a thread structure 112 of equal pitch, and the major diameter of the thread structure 112 is gradually increased in the direction away from the tapered portion 113, so that the height of the thread gradually increases in the direction away from the tapered portion 113, thereby forming a "self-tapping screw" effect, making the screwing in and out of the screw pile more labor-saving, thereby reducing the pressure dependence on the rotating construction machinery. In the specific setting, the major diameter of the thread structure 112 in the direction away from the tapered portion 113 can be gradually increased from small to large, or it can be gradually increased from small to maintain consistency after reaching a certain value, or it can be gradually increased from small to maintain consistency for a certain length after reaching a certain value, and then continue to increase. Of course, the specific method of gradually increasing the major diameter of the thread structure 112 in the direction away from the tapered portion 113 is designed according to the actual situation of the screw pile and soil conditions.

[0050] Specifically, Figure 1 As shown, a thin-walled metal cone head 400 is sleeved on the outer side of the cone portion 113 .

[0051] In the screw pile, the conical portion 113 may be a conical flat bottom structure or a conical tip, and in order to facilitate the screwing in of the screw pile, a thin-walled metal cone head 400 may be sleeved on the outer side of the conical portion 113. In soil, sand and silt without slabs and large stones, there may be small gravels, which may affect the screwing in and out of the screw column. In the specific setting, a thin-walled metal cone head 400 is sleeved on the outer side of the conical portion 113, and the conical portion 113 and the thin-walled metal cone head 400 are fixedly connected by a binder. The thin-walled metal cone head 400 can rotate together with the rotation of the housing 111, thereby being able to remove small gravels and reduce the influence of small gravels in the soil on the screw pile.

[0052] It is worth noting that the screw pile can be used as a single pile or as a multi-pile top connection. In the specific setting, when the force of a single pile exceeds 300KN or it is difficult for construction machinery to enter, a multi-pile method is used; a longer outer pile body 100 needs a vehicle-mounted spiral pile driver or a boring machine to screw in, and a shorter outer pile body 100 can be screwed in with a simple portable machine, such as a portable drilling rig for geological exploration, a portable well drilling rig, etc.

[0053] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A screw pile, characterized in that: It includes an outer pile body and a pile core, wherein: The outer pile body comprises a first pile body made of engineering plastic, the first pile body comprises a shell and a thread structure, one end of the shell is open and the other end forms a tapered portion, the thread structure is arranged on the outer surface of the shell and is integrally formed with the shell; The pile core is arranged in the shell and is anchored to the shell by at least one fastener; the pile core is reinforced concrete, the pile core includes concrete, and the concrete is poured into the shell; The fastener is a plastic-sealed steel bar, which has a plastic-coated end. The shell is provided with a through hole that penetrates the wall thickness thereof, the through hole is located between two adjacent teeth of the spiral structure, the plastic-coated end of the plastic-sealed steel bar is embedded in the through hole, and the end of the plastic-sealed steel bar away from the plastic-coated end protrudes from the through hole and is fixed in the concrete; the number of the plastic-sealed steel bars is multiple, and the multiple plastic-sealed steel bars are evenly distributed along the extension direction of the shell and evenly distributed along the circumference of the shell; A conductive column is provided on the inner wall of the shell, the conductive column is coaxially arranged with the through hole, the conductive column and the plastic-sealed head steel bar are arranged one-to-one, the plastic-sealed head steel bar passes through the conductive column, and the end away from the plastic-coated end protrudes from the end surface of the conductive column; The outer pile body comprises a second pile body, which is a plastic sleeve with two ends opened and sleeved on the outside of the pile core. The second pile body is arranged on the upper part of the outer pile body and is made of ordinary plastic.

2. The screw pile according to claim 1, characterized in that The pile core further comprises a steel cage, which is arranged in the shell and fixed to the shell.

3. The screw pile according to claim 1, characterized in that: The plastic-coated end of the plastic-sealed steel bar is coated with glue so that the plastic-coated end of the plastic-sealed steel bar is tightly matched with the through hole.

4. The screw pile according to claim 1, characterized in that: The conductive columns are evenly distributed along the circumference of the shell and evenly distributed along the axial direction of the shell.

5. The screw pile according to claim 1, characterized in that: The plastic sleeve is formed in one step by drawing or injection molding.

6. The screw pile according to claim 1, characterized in that The plastic sleeve is inserted into the shell and fixed to the shell by screws.

7. The screw pile according to claim 1, characterized in that The pile core also includes a chuck, the steel cage passes through the chuck, the chuck has a bearing surface, the plastic sleeve is sleeved on the outside of the pile core and located on the bearing surface, and the end of the steel cage away from the bearing surface is inserted into the shell.

8. The screw pile according to claim 1, characterized in that The pile core is a square steel pipe, the fastener comprises two plastic fixing plates, the square steel pipe is embedded in the two plastic fixing plates, and is fixedly connected to the shell by stainless steel screws.

9. The screw pile according to any one of claims 1 to 8, characterized in that: The thread structure has a constant pitch, a tapered portion is formed at a position where the shell is opposite to the opening, and the major diameter of the thread structure gradually increases in a direction away from the tapered portion.

10. The screw pile according to claim 9, characterized in that A thin-walled metal cone head is sleeved on the outer side of the conical portion.

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