CN220225267U - Pretensioned prestressing anti-pulling pile - Google Patents

Abstract

The utility model provides a pretensioned prestressing uplift pile, and belongs to the field of building construction. Deep foundation construction is an extremely important link in large and high-rise building construction, and a uplift pile is a key for smooth construction of main building. In areas with higher groundwater level, the multi-storey building with the buried foundation often has serious anti-floating problem, and the main countermeasure for the anti-floating of the foundation is to set a prestressed anti-floating pile. In the prior art, the prestressed anti-pulling pile is mainly implemented by adopting a post-tensioning method, the post-tensioning method needs to apply tensioning force after the anti-pulling pile is poured, the key component steel stranded wires are positioned in the anti-pulling pile pouring body, the pile body structure is possibly damaged in the tensioning process, and defects are not easy to detect. The utility model provides a pretensioned prestressing uplift pile which comprises a filling material, a reinforcement cage, a grouting device, a plurality of supporting pieces and a plurality of groups of prestressing devices, wherein the pile forming quality of the uplift pile is better, and the structural performance is stronger.

Description

Pretensioned prestressing anti-pulling pile

Technical Field

The utility model belongs to the field of building construction, and particularly relates to a pretensioned prestressing uplift pile.

Background

Deep foundation construction is an extremely important link in large and high-rise building construction, and a uplift pile is a key for smooth construction of main building. In areas with higher groundwater level, the multi-storey building with the buried foundation often has serious anti-floating problem, and the main countermeasure for the anti-floating of the foundation is to set a prestressed anti-floating pile. In the prior art, the prestressed anti-pulling pile is mainly constructed by adopting a post-tensioning method, the post-tensioning method needs to apply tensioning force after the anti-pulling pile is poured, the key component steel stranded wires are positioned in the anti-pulling pile pouring body, the pile body structure is possibly damaged in the tensioning process, and defects are not easy to detect.

Specifically, the post-tensioning method is that concrete pouring is firstly carried out before the steel strand is tensioned, after pouring is completed, the steel strand is tensioned, at the moment, two ends of the steel strand are respectively positioned at two ends of a pile body, the middle section of the steel strand is positioned in the concrete, during tensioning, the two ends of the pile body bear the reaction force of tensioning, under the strong tensioning of a jack, local stress parts at two ends of the pile body can be damaged, on the other hand, defects of the steel strand positioned in the pile body are difficult to detect, and once the steel strand is disconnected or loosened in the tensioning process, the subsequent repair difficulty is huge.

Disclosure of Invention

In view of the shortcomings of the prior art, the utility model aims to provide a pretensioned prestressing anti-pulling pile, which is used for solving the problems that pile foundation concrete and steel strands of the anti-pulling pile are damaged and quality defects are formed in the post-tensioning construction process in the prior art.

In order to achieve the above and other related objects, the present utility model provides a pretensioned prestressing uplift pile, comprising a main body frame and a filling material, wherein the main body frame is placed in a pile hole, the filling material is concrete, a casting mode is adopted to fill a gap between the pile hole and the main body frame,

the main body frame comprises a reinforcement cage, a grouting device, a plurality of supporting pieces and a plurality of groups of prestressing devices,

the bottom of the reinforcement cage is fixedly provided with a second backing plate, the bottom of the reinforcement cage is positioned at the bottom of the pile hole, the top of the reinforcement cage is fixedly provided with a first backing plate, the first backing plate is flush with the pile hole in height,

the grouting device comprises a first grouting pipe, the first grouting pipe is vertically arranged, a grouting opening of the first grouting pipe is positioned at the top of the pile hole, the tail end of the first grouting pipe is positioned at the bottom of the pile hole,

a plurality of supporting pieces pass through the first base plate and are connected to the second base plate, each supporting piece is fixedly connected with the first base plate and the second base plate through a detachable structure,

the prestress device comprises a first anchoring device, a steel strand group and a second anchoring device, wherein the first anchoring device is installed on the first base plate, the second anchoring device is installed on the second base plate, the steel strand group sequentially penetrates through the first anchoring device, the steel reinforcement cage and the second anchoring device, and the first anchoring device and the second anchoring device are used for clamping and fixing the steel strand group and maintaining the tensioning state of the steel strand group.

Optionally, the grouting device further comprises a second grouting pipe, a grouting opening of the second grouting pipe is located at the top of the pile hole, and a grouting opening of the second grouting pipe is located at the side face of the pile hole and is arranged in a layered mode.

Optionally, the steel strand group comprises a plurality of unbonded steel strands, and each unbonded steel strand is brushed with asphalt ship priming paint.

Optionally, the first anchoring device includes clamping piece, ground tackle and first spiral muscle, be equipped with a plurality of through wires holes on the ground tackle, every all be equipped with in the through wires hole the clamping piece, ground tackle fixed mounting in first backing plate upside, the spiral muscle install in first backing plate downside, many unbonded steel strands pass in proper order the clamping piece, ground tackle, first backing plate are assembled into the steel strand wires family after, and pass first spiral muscle.

Optionally, high-strength grouting material is poured into the threading hole of the anchor, and the grouting material is sulfur cement.

Optionally, the steel strand family is sleeved with a plastic tube from passing through the first anchoring device to reaching the second anchoring device, and the plastic tube is filled with butter.

Optionally, the steel reinforcement cage axis direction interval is provided with the binding member, the binding member will the plastic tubing binding is fixed, prevents the plastic tubing rocks.

Optionally, the hoop piece includes many stirrups, the stirrup both ends overlap joint be in on the steel reinforcement cage, the plastic tubing lock is fixed in on the stirrup.

Optionally, the second anchoring device includes extrusion cover, second backing plate and second spiral muscle, extrusion cover welded fastening is in second backing plate downside, the second spiral muscle is located second backing plate upside, the steel strand wires group passes behind the second spiral muscle disperse into many unbonded steel strand wires, every unbonded steel strand wires pass behind the second backing plate, pass respectively corresponding extrusion cover again in proper order.

Optionally, the outer wall of the support member is sleeved with a spacer material, and the support member can be pulled out of the spacer material.

As described above, the pretensioned prestressing uplift pile has at least the following beneficial effects:

1. the pretensioned prestressing anti-pulling pile has better pile forming quality, comprises a reinforcement cage, a grouting device, a plurality of supporting pieces and a plurality of groups of prestressing devices, wherein the prestressing devices can apply prestressing to the main framework of the anti-pulling pile, and the pretensioned process is adopted to pretension steel strands and then pour concrete, so that the construction difficulty is simplified, the damage to the concrete structure of the anti-pulling pile in the tensioning process is avoided, the pile forming quality is effectively improved, and the pile body defects are reduced;

2. the pretensioned prestressing uplift pile comprises the second grouting pipes, wherein the second grouting pipes are arranged in a layered mode, the outlets are located on the sides of the uplift pile and pile holes, after the uplift pile main body is poured, pressure grouting is conducted through the second grouting pipes, slurry is drilled into the surrounding soil layer and combined with the uplift pile main body, and therefore the combination performance of the uplift pile and the surrounding soil layer can be effectively improved, and the uplift pile anti-floating performance is improved.

Drawings

FIG. 1 is a schematic side view of a pretensioned prestressed uplift pile according to the present utility model.

FIG. 2 is a schematic cross-sectional view of a pretensioned prestressed uplift pile according to the present utility model.

Fig. 3 is a schematic view of a first anchoring device of a pretensioned prestressed uplift pile according to the present utility model.

Fig. 4 is a schematic view of a second anchoring device for pretensioned prestressed uplift pile according to the present utility model.

Wherein: pile hole 1, main body frame 2, reinforcement cage 20, stirrup 201, first backing plate 202, second backing plate 203, grouting device 21, first grouting pipe 211, second grouting pipe 212, first anchor device 231, clamping piece 2311, anchor 2312, first spiral bar 2314, steel strand family 232, unbonded steel strand 2321, plastic pipe 2320, second anchor device 233, extrusion sleeve 2331, second spiral bar 2332, support 24, and insulation 25.

Detailed Description

Further advantages and effects of the present utility model will become apparent to those skilled in the art from the disclosure of the present utility model, which is described by the following specific examples.

Please refer to fig. 1 to 4. It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the utility model to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the utility model, are included in the spirit and scope of the utility model which is otherwise, without departing from the spirit or scope thereof. Also, the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like recited in the present specification are merely for descriptive purposes and are not intended to limit the scope of the utility model, but are intended to provide relative positional changes or modifications without materially altering the technical context in which the utility model may be practiced.

The following examples are given by way of illustration only. Various embodiments may be combined and are not limited to only what is presented in the following single embodiment.

Referring to fig. 1, the utility model provides a pretensioned prestressing uplift pile, comprising a main body frame 2 and a filling material, wherein the main body frame 2 is placed in a pile hole 1, the filling material is concrete, the filling material is filled in a gap between the pile hole 1 and the main body frame 2 in a pouring manner,

the main body frame 2 comprises a reinforcement cage 20, a grouting device 21, a plurality of supporting pieces 24 and a plurality of groups of prestressing devices,

a second backing plate 203 is fixedly arranged at the bottom of the reinforcement cage 20, the bottom of the reinforcement cage 20 is positioned at the bottom of the pile hole 1, a first backing plate 202 is fixedly arranged at the top of the reinforcement cage 20, the first backing plate 202 is flush with the pile hole 1 in height,

the grouting device 21 comprises a first grouting pipe 211, the first grouting pipe 211 is vertically arranged, a grouting opening of the first grouting pipe 211 is positioned at the top of the pile hole 1, the tail end of the first grouting pipe 211 is positioned at the bottom of the pile hole 1,

a plurality of the supporting pieces 24 pass through the first pad 202 and are connected to the second pad 203, each of the supporting pieces 24 is fixedly connected to the first pad 202 and the second pad 203 by a detachable structure,

the prestress device comprises a first anchoring device 231, a steel strand group 232 and a second anchoring device 233, wherein the first anchoring device 231 is installed on the first backing plate 202, the second anchoring device 233 is installed on the second backing plate 203, the steel strand group 232 sequentially penetrates through the first anchoring device 231, the steel reinforcement cage 20 and the second anchoring device 233, and the first anchoring device 231 and the second anchoring device 233 are used for clamping and fixing the steel strand group 232 and maintaining the tensioning state of the steel strand group 232.

During construction, pile holes are dug out according to construction planning, the reinforcement cage is processed, the first base plate and the second base plate are respectively fixed on the top end face and the bottom end face of the reinforcement cage, the first base plate and the second base plate can be welded on the main reinforcement of the reinforcement cage in a welding mode, and hole sites which are convenient for follow-up construction are reserved on the first base plate and the second base plate.

And then installing a grouting device, wherein the grouting device is used for pouring cement slurry into the pile hole, a grouting opening of the grouting device is positioned outside the pile hole, an outlet of the grouting device is positioned in the pile hole, the grouting device is of a tubular structure and is axially arranged along the reinforcement cage, and a plurality of fasteners can be used for fixing the grouting device on the reinforcement cage along the way so as to prevent the grouting device from shaking or falling off in the process of placing the reinforcement cage into the pile hole.

The support piece is a key component, the bottom of the support piece is connected to a second base plate at the bottom of the reinforcement cage, the top of the support piece is connected to a first base plate at the top of the reinforcement cage, and the support piece is used for supporting the support piece between the first base plate and the second base plate to provide reaction force for the subsequent tensioning procedure.

The prestress device is used for providing and maintaining a prestress state, the first anchoring device is fixedly arranged on a first base plate at the top of the steel reinforcement cage, the second anchoring device is fixedly arranged on a second base plate at the bottom of the steel reinforcement cage, and the two are connected through a steel strand group consisting of a plurality of steel strands. During construction, the second anchoring device locks the tail end of the steel strand group, then the steel strand is tensioned at the first anchoring device, and the tensioning state is maintained by the first anchoring device, so that prestress is formed on the steel strand group.

In the tensioning process, because the two ends of the steel strand group are respectively connected to the first backing plate and the second backing plate at the two ends of the steel reinforcement cage, the tensioning of the steel strand group can be converted into the compression of the first backing plate and the second backing plate to the middle part of the steel reinforcement cage, and the steel reinforcement cage is used as a cage-shaped structure woven by steel reinforcement, and is easy to deform and shrink when stressed. In this case, the amount of tension of the steel strand family is derived from the amount of shrinkage deformation of the reinforcement cage, not the amount of elongation of the steel strand family itself, that is, even if the tension is in compliance with the design specifications from the surface, the prestress inside the actual steel strand family does not meet the specifications.

The supporting piece has the function of solving the problems, and in the tensioning process, the supporting piece is propped between the first base plate and the second base plate to prevent the shrinkage deformation of the steel reinforcement cage, so that the tensioning amount of the steel strand group is ensured to be derived from the elongation deformation of the steel strand group, but not from the shrinkage deformation of the steel reinforcement cage, and the steel strand group is ensured to have enough prestress.

After the pile is poured, the steel strand family is positioned inside the pile, and has a shrinkage restoration prestress due to the fact that the steel strand family is elongated in advance, and the prestress can act on the pile pouring body, so that the whole pile is tightened from two ends to the middle.

When the common anti-pulling pile works in a region with higher underground water level, a multi-layer building with a buried foundation often has serious anti-floating problem, namely, tensile stress is formed on the anti-pulling pile, concrete in the tensile stress region cracks earlier after the common anti-pulling pile is pulled, and steel bars are exposed in the underground water and are easy to corrode, so that the anti-pulling performance of the multi-layer building is damaged, and the safety of the building is affected. The uplift pile of the embodiment has prestress, and the prestress can exactly offset part of the uplift stress, so that the pile body has better mechanical property.

In addition, the anti-pulling pile is obtained through pretensioning construction, the concrete of the main body structure is not poured when the steel strand is tensioned, and the pile body concrete structure is not damaged when the steel strand is tensioned, so that the construction difficulty is simplified, the damage of the anti-pulling pile concrete structure in the tensioning process is avoided, the pile forming quality is effectively improved, and the pile body defects are reduced.

In the above embodiment, the steel pipe as the supporting member is fixedly connected to the first pad and the second pad, and the second pad at the bottom of the pile hole cannot be manually detached once being placed into the pile hole along with the main body frame. In this embodiment, however, a detachable structure is required, which is intended to facilitate subsequent recovery of the support member. Specifically, the support piece can be temporarily fixed on the second backing plate in a spot welding mode, and once the pulling-out pile is pulled and poured, the support piece can be pulled out of the pulling-out pile and recovered by twisting the support piece to enable the welding spots to fall off. The detachable connection of the support element to the first backing plate is preferably performed by manual operation, in that it can be welded and then cut, or held by a bolt set and a clamping structure, or in a number of other ways.

Referring to fig. 1, the grouting device 21 further includes a second grouting pipe 212, a grouting opening of the second grouting pipe 212 is located at the top of the pile hole 1, and a grouting opening of the second grouting pipe 212 is located at a side surface of the pile hole 1 and is layered.

The principle of the uplift pile is that the soil layer can effectively overcome the axial tension of the pile body through friction on the pile, and in the embodiment, the second grouting pipe is used for secondary grouting. During construction, the first grouting pipe is used for completing integral grouting, after the grouting is solidified to a certain degree, the second grouting pipe is used for carrying out pressure grouting, so that slurry is drilled into soil layers around pile holes and combined with the anti-floating pile body, the combination performance of the anti-floating pile and the surrounding soil layers can be effectively improved, and the anti-floating effect of the anti-floating pile is improved.

Referring to fig. 3 and 4, the steel strand family 232 includes a plurality of unbonded steel strands 2321, and each unbonded steel strand 2321 is coated with an asphalt primer.

A plurality of unbonded steel strands are woven into a whole, so that the mechanical property can be effectively improved, and compared with a common single prestress pile body, the mode of the steel strand group is more reliable. Firstly, the same number of unbonded steel strands is higher in comprehensive bearing capacity after being woven into a steel strand group, and secondly, when a single unbonded steel strand is loosened or broken, the whole load is still in the bearing range of the steel strand group.

In the conventional single unbonded steel strand anti-pulling pile, once one of the unbonded steel strands fails, the surrounding unbonded steel strands share larger load, so that the service life is reduced, and once the unbonded steel strands are damaged, the unbonded steel strands are further transmitted to the surrounding, so that the service life of the anti-pulling pile is accelerated.

The asphalt ship primer has better alkali resistance and excellent rust resistance, and the steel strand group asphalt ship primer can form a protective layer to delay rust.

Referring to fig. 3, the first anchoring device 231 includes a clamping piece 2311, an anchor 2312 and a first spiral rib 2314, a plurality of threading holes are formed in the anchor 2312, the clamping piece 2311 is disposed in each threading hole, the anchor 2312 is fixedly mounted on the upper side of the first backing plate 202, the spiral rib is mounted on the lower side of the first backing plate 202, and a plurality of unbonded steel strands 2321 sequentially pass through the clamping piece 2311, the anchor 2312 and the first backing plate 202 and then are gathered into the steel strand group 232 and pass through the first spiral rib 2314.

The clamping piece type anchorage device is a self-anchored anchorage device which is brought into the clamping piece by retracting the steel strand, has stable anchoring performance, uniform stress, safety and reliability, and wide application range of anchoring the steel strand. Under the action of external tension force, the steel strand has strong retractive force, and the retractive force generates great clamping capacity of the clamping piece to the steel strand.

After concrete pouring is completed, local high-strength tensioning stress exists in the contact area between the installation area of the anchor and the concrete, and the first spiral ribs have the function of dispersing the compressive strength of the tensioned concrete and preventing the local area of the concrete from being crushed, so that the pile quality of the uplift pile is influenced.

In this embodiment, the high-strength grouting material is poured into the threading hole of the anchor 2312, and the grouting material is sulfur cement.

The prestress is the key performance of the anti-pulling pile, and is provided by the tension amount of the steel strand group after the anchoring device maintains the tension. The sulfur cement is poured into the anchor, so that the impermeability and acid and alkali resistance of the anchor can be improved, the anchor and the clamping piece are protected, corrosion of the anchor is effectively prevented, meanwhile, the friction force between the steel strand and the clamping piece is increased, the anchoring effect of the steel strand group is ensured to be stable all the time, the prestress of the uplift pile is always present in a longer expected working period, and the comprehensive performance of the uplift pile is maintained.

Referring to fig. 2, the steel strand family 232 is sleeved with a plastic pipe 2320 from passing through the first anchoring device 231 to reaching the second anchoring device 233, and the plastic pipe 2320 is filled with butter.

Before concrete pouring, the plastic pipe can fix a plurality of unbonded steel strands together to prevent the steel strand groups from being scattered into a plurality of scattered unbonded steel strands, and when the plurality of unbonded steel strands are converged into an integral steel strand group, loads can be distributed among the steel strand groups, so that the integral mechanical property is better; when concrete is poured, the plastic pipe can separate the steel strand group from concrete, so that the steel strand group can still move in the concrete pile body, and the concrete pile body has the advantages that the steel strand group can be further tensioned after construction is completed, the tensioning amount before correction can be tensioned in the life process of the anti-pulling pile, and the prestress loss of the anti-pulling pile can be repaired.

One effect of butter is lubrication, reduces the friction between the unbonded steel strands in the tensioning process, and the other effect is corrosion prevention, wraps the surface of the unbonded steel strands, reduces the contact between the unbonded steel strands and air, can effectively delay the oxidation process of the unbonded steel strands, improves the effective life of the unbonded steel strands, and further improves the overall life of the uplift pile.

Referring to fig. 2, tightening members are disposed at intervals in the axial direction of the reinforcement cage 20, and the tightening members tighten and fix the plastic pipe 2320, so as to prevent the plastic pipe 2320 from shaking. Further, the tightening piece comprises a plurality of hoops 201, two ends of each hoop 201 are lapped on the reinforcement cage 20, and the plastic pipe 2320 is tightened and fixed on the hoops 201.

In fig. 2, 3 stirrups are used to form a triangle, and are connected together in pairs and are jointly lapped on the reinforcement cage, so that the reinforcement cage can be used for fixing a plastic pipe sleeved with a steel strand group, and also can be used for fixing a supporting piece, the steel strand group and the supporting piece are prevented from shaking and shifting in the pile hole process when the reinforcement cage is lowered, and once the situation occurs, the repairing process is very complicated, the reinforcement cage needs to be lifted out of the pile hole, and the construction period and the cost are wasted.

Referring to fig. 4, the second anchoring device 233 includes an extrusion sleeve 2331, a second backing plate 203 and a second spiral rib 2332, the extrusion sleeve 2331 is welded and fixed on the lower side of the second backing plate 203, the second spiral rib 2332 is located on the upper side of the second backing plate 203, the steel strand group 232 passes through the second spiral rib 2332 and then is dispersed into a plurality of unbonded steel strands 2321, and each unbonded steel strand 2321 passes through the corresponding extrusion sleeve 2331 after passing through the second backing plate 203.

When the method is specifically implemented, the steel strand passes through the second anchoring device, the tail end of the steel strand is positioned in the extrusion sleeve, after the installation is confirmed to be correct, the extrusion sleeve is clamped by a special crimping machine, the extrusion sleeve is compressed and deformed, the steel strand is clamped, the tail end of the steel strand is fixed, and the steel strand at one end of the pile top is tensioned, so that a prestress state can be formed.

In this embodiment, referring to fig. 2, the outer wall of the supporting member 24 is sleeved with a spacer material 25, and the supporting member 24 may be pulled out from the spacer material 25.

After the steel strand group is tensioned, the first anchoring device at one end of the pile top can automatically lock the steel strand, so that the prestress state is maintained. At this time, concrete pouring is carried out, the concrete slurry is filled in the gap between the pile hole and the main body frame, and the final anti-pulling pile is formed after solidification.

Because the concrete in the uplift pile is solidified, even if the supporting piece used as a support is taken away, the original stretching amount of the steel strand group can be maintained, so that the prestress state of the whole pile body is maintained. Recycling the support is more economically valuable from a cost and materials standpoint.

When retrieving, twist support earlier, destroy the fixed connection of support and second backing plate, in the aforesaid embodiment, provide a spot welding's connected mode, can provide the connectivity, can provide the dismantlement convenience again. In addition, the fixed connection between the support piece and the first backing plate is released, but because the first backing plate is positioned at the pile top, the manual operation is convenient, and the detachable mode is quite large. The effect of isolation material is isolation concrete and support piece, prevents that support piece from being solidified by the concrete and increasing the dismantlement degree of difficulty together, and isolation material has reduced support piece's the recovery degree of difficulty, has also avoided using the powerful support piece that draws when retrieving, and then avoids destroying pile quality, has effectively improved construction convenience and piling quality.

In summary, the utility model effectively overcomes various defects in the prior art, and has high industrial utilization value.

The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (10)

1. The pretensioned prestressing uplift pile comprises a main body frame (2) and filling materials, wherein the main body frame (2) is placed in a pile hole (1), the filling materials are concrete, and a pouring mode is adopted to fill a gap between the pile hole (1) and the main body frame (2),

the main body frame (2) comprises a reinforcement cage (20), a grouting device (21), a plurality of supporting pieces (24) and a plurality of groups of prestress devices,

the bottom of the steel reinforcement cage (20) is fixedly provided with a second backing plate (203), the bottom of the steel reinforcement cage (20) is positioned at the bottom of the pile hole (1), the top of the steel reinforcement cage (20) is fixedly provided with a first backing plate (202), the first backing plate (202) is flush with the pile hole (1),

the grouting device (21) comprises a first grouting pipe (211), the first grouting pipe (211) is vertically arranged, a grouting opening of the first grouting pipe (211) is positioned at the top of the pile hole (1), the tail end of the first grouting pipe (211) is positioned at the bottom of the pile hole (1),

a plurality of the supporting pieces (24) penetrate through the first base plate (202) and are connected to the second base plate (203), each supporting piece (24) is fixedly connected with the first base plate (202) and the second base plate (203) through a detachable structure,

the prestress device comprises a first anchoring device (231), a steel strand group (232) and a second anchoring device (233), wherein the first anchoring device (231) is installed on the first backing plate (202), the second anchoring device (233) is installed on the second backing plate (203), the steel strand group (232) sequentially penetrates through the first anchoring device (231), the steel reinforcement cage (20) and the second anchoring device (233), and the first anchoring device (231) and the second anchoring device (233) are used for clamping and fixing the steel strand group (232) and maintaining the tensioning state of the steel strand group.

2. Pretensioned prestressed uplift pile according to claim 1, characterized in that the grouting device (21) further comprises a second grouting pipe (212), the grouting opening of the second grouting pipe (212) is located at the top of the pile hole (1), and the grouting opening of the second grouting pipe (212) is located at the side surface of the pile hole (1) and is arranged in layers.

3. The pretensioned prestressed uplift pile of claim 1, wherein said steel strand family (232) includes a plurality of unbonded steel strands (2321), each of said unbonded steel strands (2321) being primed with an asphalt primer.

4. A pretensioned prestressing pile according to claim 3, wherein the first anchoring device (231) comprises a clamping piece (2311), an anchor (2312) and a first spiral rib (2314), a plurality of threading holes are formed in the anchor (2312), the clamping piece (2311) is arranged in each threading hole, the anchor (2312) is fixedly arranged on the upper side of the first backing plate (202), the spiral rib is arranged on the lower side of the first backing plate (202), and a plurality of unbonded steel strands (2321) sequentially penetrate through the clamping piece (2311), the anchor (2312) and the first backing plate (202) to form a steel strand group (232) and penetrate through the first spiral rib (2314).

5. The pretensioned prestressed uplift pile of claim 4, wherein said anchor (2312) is provided with a high strength grouting material in its threading hole, said grouting material being sulfur cement.

6. Pretensioned prestressed uplift pile according to claim 1, characterized in that the steel strand family (232) is sleeved with a plastic pipe (2320) from passing through the first anchoring device (231) to reaching the second anchoring device (233), and that the plastic pipe (2320) is filled with butter.

7. Pretensioning prestressed uplift pile according to claim 6, characterized in that the reinforcement cage (20) is provided with tightening members at intervals in the axial direction, which tightening members tighten and fix the plastic pipe (2320) against shaking of the plastic pipe (2320).

8. The pretensioned prestressed uplift pile of claim 7, wherein said hooping member includes a plurality of stirrups (201), both ends of said stirrups (201) are overlapped on said reinforcement cage (20), and said plastic pipe (2320) is fastened to said stirrups (201).

9. The pretensioned prestressed uplift pile according to claim 1, wherein the second anchoring device (233) comprises an extrusion sleeve (2331), a second backing plate (203) and a second spiral rib (2332), the extrusion sleeve (2331) is welded and fixed on the lower side of the second backing plate (203), the second spiral rib (2332) is located on the upper side of the second backing plate (203), the steel strand family (232) is dispersed into a plurality of unbonded steel strands (2321) after passing through the second spiral rib (2332), and each unbonded steel strand (2321) passes through the respective extrusion sleeve (2331) after passing through the second backing plate (203).

10. Pretensioned prestressed uplift pile according to claim 1, characterized in that the outer wall of the support member (24) is covered with a spacer material (25), said support member (24) being extractable from said spacer material (25).