Post-grouting steel pipe pile and grouting method

Abstract

The present invention discloses a post-grouting steel pipe pile and a grouting method. The post-grouting steel pipe pile comprises a steel pipe pile, a grouting pipe and an exhaust pipe. The steel pipe pile is radially provided with a plurality of partitions, and a grouting closed space is formed between two adjacent partitions. The grouting pipe is axially arranged along the inner side of the pile wall of the steel pipe pile, and a grouting outlet is arranged in a plurality of grouting closed spaces for grouting into the grouting closed space. The exhaust pipe is axially arranged along the inner side of the pile wall of the steel pipe pile, and an exhaust outlet is arranged in a plurality of grouting closed spaces for venting the grouting closed space outward when grouting into the grouting closed space. The present invention forms a multi-segment solid pile body by grouting into a plurality of grouting closed spaces arranged in the pile body of the steel pipe pile. While improving the overall stiffness of the steel pipe pile, the number of segments of the solid pile body can be selected according to the construction soil working conditions, thereby reducing the grouting cost, and solving the technical problems of low bending stiffness, great construction difficulty and waste of materials of the current steel pipe pile.

Description

Technical Field

[0001] The invention relates to the technical field of steel pipe piles, and in particular to a post-grouting steel pipe pile and a grouting method. Background Art

[0002] At present, steel pipe piles are widely used in the field of engineering construction due to their mature technology, reliable quality, and fast construction speed. However, due to their shape and material characteristics, the flexural stiffness (cross-sectional flexural stiffness) of steel pipe piles is smaller than that of other building materials. In order to obtain greater flexural stiffness, the pile diameter must be increased or the pipe wall thickness must be increased, resulting in material waste and increased construction difficulty. This is especially serious when steel pipe piles are used mainly to resist horizontal forces (such as foundation pits, slope support, etc.). Summary of the invention

[0003] The main purpose of the present invention is to provide a post-grouting steel pipe pile and a grouting method, aiming to solve the technical problems of low bending stiffness, great construction difficulty, waste of materials and low vertical bearing capacity of single pile when facing working conditions mainly resisting horizontal forces.

[0004] To achieve the above object, the present invention provides a post-grouting steel pipe pile, comprising:

[0005] The steel pipe pile is provided with a plurality of partitions in the radial direction, and a grouting closed space is formed between two adjacent partitions;

[0006] A grouting pipe is arranged along the inner side of the pile wall of the steel pipe pile and is provided with grouting outlets in a plurality of grouting closed spaces for grouting into the grouting closed spaces;

[0007] The exhaust pipe is axially arranged along the inner side of the pile wall of the steel pipe pile. The grouting pipe is provided with exhaust ports in several grouting closed spaces for exhausting the grouting closed spaces to the outside when grouting is performed in the grouting closed spaces.

[0008] Optionally, the partition includes a top partition and a bottom partition, and the slurry outlet and the exhaust port are arranged in a plurality of grouting closed spaces near the lower side of the top partition.

[0009] Optionally, the bottom of the steel pipe pile adopts a closed pile tip structure or an open pile tip structure.

[0010] Optionally, the pile wall of the grouting closed space and / or the inclined wall of the pile tip structure is provided with a plurality of grouting holes, and the grouting holes are used for grouting into the soil outside the steel pipe pile.

[0011] Optionally, each of the grouting holes is provided with a hole plug structure, and the hole plug structure is pushed out of the grouting hole when the grouting pressure of the grouting closed space reaches a preset condition.

[0012] Optionally, the corresponding grouting pressure when the hole plug structure of each grouting closed space is pushed out of the grouting hole is independently set.

[0013] Optionally, the hole plug structure includes a hole plug portion and a limiting portion which are connected to each other. When the hole plug structure is installed in the grouting hole, the hole plug portion is located in the grouting hole, and the limiting portion is located outside the steel pipe pile.

[0014] Optionally, the grouting pipe and the exhaust pipe are arranged opposite to each other in the steel pipe pile.

[0015] Optionally, the grouting port of the grouting pipe is provided with a grouting pipe closing cap, and the air outlet of the exhaust pipe is provided with an exhaust pipe closing cap.

[0016] In addition, in order to achieve the above object, the present invention also provides a grouting method, using the post-grouting steel pipe pile as described above, the method comprising:

[0017] S1: After the steel pipe pile sinking construction is completed, grouting is injected into the grouting pipe under the preset grouting pressure;

[0018] S2: When the slurry is injected into each grouting closed space formed by the top plate and the bottom plate through the slurry outlet from bottom to top and flows out through the gas outlet of the exhaust pipe, the grouting is stopped;

[0019] S3: The grouting port of the grouting pipe and the air outlet of the exhaust pipe are closed, and after the slurry in the grouting closed space solidifies, a plurality of solid pile sections are formed.

[0020] Optionally, the grouting pressure is preset to normal atmospheric pressure.

[0021] Optionally, when the pile wall and / or the inclined wall of the pile tip structure of the grouting closed space is provided with a plurality of grouting holes, and each of the grouting holes is equipped with a hole plug structure, the step S3 specifically includes:

[0022] S31: closing the gas outlet of the exhaust pipe, pressurizing grouting until the plug structure on the grouting hole is pushed out of the grouting hole under the pressure of the grouting liquid, and injecting the grouting liquid into the soil outside the steel pipe pile;

[0023] S32: When the grouting volume and / or grouting pressure of the soil outside the steel pipe pile reaches a preset condition, the grouting is stopped, the grouting port of the grouting pipe is closed, and after the slurry in the grouting closed space and outside the steel pipe pile solidifies, a multi-section solid pile body and a plurality of reinforcement bodies outside the pile body are formed.

[0024] The embodiment of the present invention proposes a post-grouting steel pipe pile and a grouting method. The post-grouting steel pipe pile includes a steel pipe pile, a grouting pipe and an exhaust pipe. The steel pipe pile is radially provided with a plurality of partitions, and a grouting closed space is formed between two adjacent partitions. The grouting pipe is axially arranged along the inner side of the pile wall of the steel pipe pile, and grouting outlets are arranged in several grouting closed spaces for grouting into the grouting closed spaces. The exhaust pipe is axially arranged along the inner side of the pile wall of the steel pipe pile, and exhaust outlets are arranged in several grouting closed spaces for exhausting the grouting closed spaces to the outside when grouting into the grouting closed spaces. The present invention forms a multi-section solid pile body by grouting into a plurality of grouting closed spaces arranged in the pile body of the steel pipe pile. While improving the overall stiffness of the steel pipe pile, the number of sections of the solid pile body can be selected according to the construction soil working conditions to ensure the grouting cost and the strength of the steel pipe pile. This solves the technical problems of low bending stiffness, great construction difficulty, waste of materials and low vertical bearing capacity of a single pile in the current steel pipe pile when facing working conditions mainly requiring resistance to horizontal forces. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a first structural schematic diagram of a steel pipe pile in the present invention;

[0026] Figure 2 is a second structural schematic diagram of a steel pipe pile in the present invention;

[0027] Figure 3 It is a schematic flow diagram of the grouting method of the present invention.

[0028] Description of reference numerals:

[0029] 1-steel pipe pile; 2-grouting pipe; 3-slurry outlet; 4-exhaust pipe; 5-exhaust outlet; 6-partition; 7-grouting hole; 8-hole plug structure; 9-grouting pipe closing cap; 10-exhaust pipe closing cap.

[0030] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0031] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0032] The following will be combined with the drawings in the embodiments of the invention to clearly and completely describe the technical solutions in the embodiments of the invention. Obviously, the described embodiments are only part of the embodiments of the invention, not all of the embodiments. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0033] It should be noted that all directional indications in the embodiments of the invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection required by the invention.

[0035] At present, in the relevant technical field, the existing steel pipe piles have low bending stiffness, great construction difficulty and waste of materials.

[0036] In order to solve this problem, various embodiments of the post-grouting steel pipe pile and the grouting method of the present invention are proposed. The post-grouting steel pipe pile and the grouting method provided by the present invention form a multi-segment solid pile body by grouting multiple grouting closed spaces set in the pile body of the steel pipe pile. While improving the overall rigidity of the steel pipe pile, the number of segments of the solid pile body can be selected according to the construction soil working conditions to ensure the grouting cost and the strength of the steel pipe pile, solving the technical problems of low bending rigidity, great construction difficulty and waste of materials when the current steel pipe pile faces the working conditions of resisting horizontal forces.

[0037] The present invention provides a first embodiment of a post-grouting steel pipe pile.

[0038] In this embodiment, the post-grouting steel pipe pile includes a steel pipe pile 1, a grouting pipe 2 and an exhaust pipe 4.

[0039] It should be noted that, refer to Figure 1 The steel pipe pile 1 is radially provided with a plurality of partitions 6, and a grouting closed space is formed between two adjacent partitions 6; a grouting pipe 2 is axially arranged along the inner side of the pile wall of the steel pipe pile 1, and the grouting pipe 2 is provided with slurry outlets 3 in several grouting closed spaces for grouting into the grouting closed spaces; an exhaust pipe 4 is axially arranged along the inner side of the pile wall of the steel pipe pile 1, and the grouting pipe 2 is provided with exhaust ports 5 in several slurry closed spaces for exhausting the grouting closed spaces to the outside when grouting into the grouting closed spaces.

[0040] In a preferred embodiment, the partition 6 includes a top partition 6 and a bottom partition 6, and the slurry outlet 3 and the exhaust port 5 are arranged near the lower side of the top partition 6 in a plurality of grouting closed spaces.

[0041] Therefore, each grouting closed space can be filled when grouting is performed, and the grouting on the upper side is performed only after the grouting closed space on the lower side is filled. When the grouting is completed, several grouting closed spaces provided with slurry outlets 3 and exhaust ports 5 are all filled with slurry, thereby improving the overall strength of the steel pipe pile 1 as much as possible and avoiding space waste in the grouting closed space.

[0042] In a preferred embodiment, the bottom of the steel pipe pile 1 adopts a closed pile tip structure or an open pile tip structure. When the closed pile tip structure is adopted, the lowermost end of the steel pipe pile 1 is composed of the closed pile tip structure and a top plate to form a grouting closed space; when the open pile tip structure is adopted, the lowermost opening of the steel pipe pile 1 is in direct contact with the soil, and the slurry is injected into the soil during grouting. After the slurry solidifies, the soil and the slurry together form a reinforcement body, thereby improving the anti-deviating property and stability of the steel pipe pile 1.

[0043] In a preferred embodiment, Figure 2 As shown, the number of the grouting pipe 2 and the exhaust pipe 4 in the steel pipe pile 1 can be multiple, and the grouting pipe 2 and the exhaust pipe 4 are arranged opposite to each other in the steel pipe pile 1 .

[0044] Thus, by placing the grouting pipe 2 and the exhaust pipe 4 as far as possible inside the steel pipe pile 1, it is possible to prevent the exhaust pipe 4 from being blocked by the grouting liquid before the grouting closed space is filled when the grouting pipe 2 is grouting, resulting in the grouting of the upper grouting closed space after the lower grouting closed space is filled. Furthermore, by placing them in relative positions, the overall strength of the steel pipe pile 1 can be improved as much as possible, and the space waste in the grouting closed space can be avoided.

[0045] In a preferred embodiment, in order to improve the adaptability of the steel pipe pile 1 in construction under different soil conditions and further reduce the grouting consumables of the steel pipe pile 1, selective grouting can also be performed on the grouting closed space in the steel pipe pile 1, that is, the grouting outlet 3 of the grouting pipe 2 and the exhaust outlet 5 of the exhaust pipe 4 are selectively set in several grouting closed spaces.

[0046] Specifically, before pile driving construction, the soil conditions at different depths below the construction location are detected, and then the grouting outlet 3 of the grouting pipe 2 and the exhaust outlet 5 of the exhaust pipe 4 are set for the grouting closed spaces at different positions of the steel pipe pile 1 according to the different soil conditions. At this time, the grouting outlet 3 of the grouting pipe 2 and the exhaust outlet 5 of the exhaust pipe 4 are set in different grouting closed spaces, and after grouting, multiple sections of solid pile bodies can be formed at preset positions, and the positions of the solid pile bodies are adapted to the soil conditions at different depths, so that the bending stiffness of the steel pipe pile 1 at different depths is associated with the soil conditions.

[0047] For example: when it is detected that the soil at the first depth position of the construction location has the characteristics of high stress and active soil creep, the grouting outlet 3 of the grouting pipe 2 and the exhaust port 5 of the exhaust pipe 4 are set in the grouting closed space corresponding to this depth position to form a solid pile body in this section and improve the bending stiffness of the steel pipe pile 1 at this depth position.

[0048] For another example, when it is detected that the second depth position of the construction location has the characteristics of low stress and inactive soil creep, the grouting outlet 3 of the grouting pipe 2 and the exhaust port 5 of the exhaust pipe 4 are not set in the grouting closed space corresponding to this depth position. Due to the characteristics of the soil itself, the steel pipe pile 1 is not easily deformed and bent due to stress. At this time, grouting can be saved by not performing grouting.

[0049] Based on the above method, after detecting the soil conditions at different depths below the construction location, the grouting outlet 3 of the grouting pipe 2 and the exhaust outlet 5 of the exhaust pipe 4 are selectively set in the grouting closed space according to the soil conditions to control the positions at which the multiple sections of solid pile bodies are formed in the steel pipe pile 1, thereby improving the bending stiffness of the steel pipe pile 1 and saving slurry consumables.

[0050] In this embodiment, a post-grouting steel pipe pile is provided. Considering that the steel pipe pile 1 needs to withstand certain compressive and bending forces during pile sinking construction, it is necessary to ensure that it can sink to the designed depth and maintain the integrity of the pile body and cannot be deformed during the pile sinking process. This requires that the steel pipe pile 1 itself needs to have a certain strength and rigidity. This embodiment adopts selective segmented grouting, and designs the number and position of the solid pile body according to the actual construction soil layer working conditions. It can not only improve the overall rigidity of the steel pipe pile 1 to meet the design requirements, but also save a lot of grouting to save costs.

[0051] The present invention also provides a second embodiment of a post-grouting steel pipe pile.

[0052] In this embodiment, the post-grouting steel pipe pile includes a steel pipe pile 1, a grouting pipe 2 and an exhaust pipe 4.

[0053] It should be noted that the steel pipe pile 1 is radially provided with a plurality of partitions 6, and a grouting closed space is formed between two adjacent partitions 6; the grouting pipe 2 is axially arranged along the inner side of the pile wall of the steel pipe pile 1, and the grouting pipe 2 is provided with slurry outlets 3 in several grouting closed spaces for grouting into the grouting closed spaces; the exhaust pipe 4 is axially arranged along the inner side of the pile wall of the steel pipe pile 1, and the grouting pipe 2 is provided with exhaust ports 5 in several slurry closed spaces for exhausting the grouting closed spaces to the outside when grouting is performed into the grouting closed spaces.

[0054] On the basis of the above contents, in this embodiment, a plurality of grouting holes 7 are provided on the pile wall and / or the inclined wall of the pile tip structure of the grouting closed space, and the grouting holes 7 are used for grouting into the soil outside the steel pipe pile 1 .

[0055] Therefore, grouting holes 7 can be set on the pile wall and the inclined wall of the pile tip structure of the grouting closed space, and the slurry can be injected into the soil around the steel pipe pile 1 through the grouting holes 7. After the slurry solidifies, the soil and the slurry together form a plurality of reinforcement bodies, which can increase the pile side friction resistance and pile end resistance, thereby greatly improving the vertical bearing capacity and horizontal bearing capacity of the single pile, thereby reducing the unit bearing capacity cost.

[0056] It should be noted that the grouting port of the grouting pipe 2 is provided with a grouting pipe closing cap 9 , and the air outlet of the exhaust pipe 4 is provided with an exhaust pipe closing cap 10 .

[0057] It is easy to understand that in order to realize grouting into the soil body around the steel pipe pile 1, it is necessary to first complete the grouting action of several grouting closed spaces in the steel pipe pile 1, and then perform the grouting action into the soil body. Therefore, in this embodiment, by setting a grouting pipe closing cap 9 at the grouting port of the grouting pipe 2 and setting an exhaust pipe closing cap 10 at the exhaust port of the exhaust pipe 4, after completing the grouting action of several grouting closed spaces in the steel pipe pile 1, the exhaust pipe closing cap 10 is closed, and the steel pipe pile 1 is constructed into a closed space, and the slurry can be injected into the grouting hole 7 by increasing the grouting pressure.

[0058] In a preferred embodiment, each of the grouting holes 7 is provided with a hole plug structure 8, and the hole plug structure 8 is pushed out of the grouting hole 7 when the grouting pressure of the grouting closed space reaches a preset condition.

[0059] It is easy to understand that in order to realize the grouting sequence of first inside the steel pipe pile 1 and then outside the steel pipe pile 1, a hole plug structure 8 is installed in the grouting hole 7. After the grouting inside the steel pipe pile 1 is completed, the hole plug structure 8 is pushed out of the grouting hole 7 by the grouting pressure, thereby realizing grouting outside the steel pipe pile 1.

[0060] In a preferred embodiment, the hole plug structure 8 includes a hole plug portion and a stopper portion connected to each other, and when the hole plug structure 8 is installed in the grouting hole 7, the hole plug portion is located inside the grouting hole 7, and the stopper portion is located outside the steel pipe pile 1. In this embodiment, the hole plug structure 8 can be a rivet.

[0061] In a preferred embodiment, in order to improve the adaptability of the steel pipe pile 1 in construction under different soil conditions, further improve the pile side friction resistance and pile end resistance, thereby greatly improving the vertical bearing capacity and horizontal bearing capacity of the single pile, and thus reducing the unit bearing capacity cost, the corresponding grouting pressure when the plug structure 8 of each grouting closed space is pushed out of the grouting hole 7 can also be independently set.

[0062] Specifically, before the pile driving construction, the soil conditions at different depths below the construction location are detected, and then according to the different soil conditions, grouting holes 7 and hole plug structures 8 are set for the grouting closed spaces at different positions of the steel pipe pile 1. At this time, the connection tightness of the grouting holes 7 and the hole plug structure 8 can be adapted to the different soil conditions, so that the grouting sequence and grouting amount outside the steel pipe pile 1 are related to the soil conditions at that location.

[0063] For example: when it is detected that the soil at the third depth position of the construction location is soft, porous or has low soil friction, the connection tightness of the grouting hole 7 and the pore structure of the grouting closed space corresponding to this depth position is set to be smaller. When grouting outside the steel pipe pile 1, by gradually increasing the grouting pressure, the hole plug structure 8 of the grouting closed space can be pushed out earlier, and then the soil outside the steel pipe pile 1 at this position can be grouted earlier. After the grouting is completed, a larger reinforcement body is formed around it, which increases the pile side friction resistance and pile end resistance, thereby greatly improving the vertical bearing capacity and horizontal bearing capacity of the single pile, thereby reducing the unit bearing capacity cost.

[0064] For another example: when it is detected that the fourth depth position of the construction location has the characteristics of hardness, few voids or large soil friction, the connection tightness of the grouting hole 7 and the porous structure of the grouting closed space corresponding to this depth position is set to be larger. When grouting the outside of the steel pipe pile 1, due to the characteristics of the soil itself, the steel pipe pile 1 has good anti-deviability, stability and pull-out bearing capacity against horizontal forces after pile sinking construction. At this time, grouting the outside of the steel pipe pile 1 can be carried out at a later time, and the reinforcement body formed around it is also smaller, saving slurry consumables.

[0065] Based on the above method, after detecting the soil conditions at different depths below the construction location, the tightness of the grouting holes 7 and the plug structure 8 corresponding to each grouting closed space is independently set to control the size of the reinforcement body formed at the corresponding position outside each grouting closed space, thereby increasing the pile side friction resistance and pile end resistance, providing the vertical bearing capacity and horizontal bearing capacity of the single pile, reducing the unit bearing capacity cost, and saving slurry consumables.

[0066] It should be noted that the tightness of the connection between the grouting hole 7 and the plug structure 8 can be achieved by setting different connection diameters of the grouting hole 7 and the plug structure 8 or setting different interference fit sizes.

[0067] In this embodiment, a post-grouting steel pipe pile is provided, considering that the steel pipe pile 1 needs to have certain anti-deviability, stability and pull-out bearing capacity against horizontal force after pile sinking construction. In this embodiment, the order and amount of grouting to the outside of the steel pipe pile 1 are controlled, and the size and position of the reinforcement body are designed according to the actual construction soil layer working condition requirements, which can not only improve the pile side friction resistance and pile end resistance, provide the vertical bearing capacity and horizontal bearing capacity of the single pile, reduce the unit bearing capacity cost to meet the design requirements, but also save a lot of grouting volume to save costs.

[0068] The invention also provides an embodiment of a grouting method.

[0069] In this embodiment, Figure 3 As shown, the grouting method adopts the post-grouting steel pipe pile as described in the previous embodiment, and the grouting method specifically includes:

[0070] S1: After the steel pipe pile sinking construction is completed, grouting is injected into the grouting pipe under the preset grouting pressure;

[0071] S2: When the slurry is injected from bottom to top through the slurry outlet into a plurality of grouting closed spaces formed by the top plate and the bottom plate, and flows out through the gas outlet of the exhaust pipe, the grouting is stopped;

[0072] S3: The grouting port of the grouting pipe and the air outlet of the exhaust pipe are closed, and after the slurry in the grouting closed space solidifies, a plurality of solid pile sections are formed.

[0073] Therefore, this embodiment adopts selective segmented grouting, and designs the number and position of the solid pile body according to the actual construction soil working conditions. It can not only improve the overall stiffness of the steel pipe pile to meet the design requirements, but also save a lot of grouting volume to save costs.

[0074] In a preferred embodiment, the preset grouting pressure is normal atmospheric pressure.

[0075] In a preferred embodiment, when the pile wall and / or the inclined wall of the pile tip structure of the grouting closed space is provided with a plurality of grouting holes, and each of the grouting holes is equipped with a hole plug structure, step S3 specifically includes:

[0076] S31: closing the gas outlet of the exhaust pipe, pressurizing grouting until the plug structure on the grouting hole is pushed out of the grouting hole under the pressure of the grouting liquid, and injecting the grouting liquid into the soil outside the steel pipe pile;

[0077] S32: When the grouting volume and / or grouting pressure of the soil outside the steel pipe pile reaches a preset condition, the grouting is stopped, the grouting port of the grouting pipe is closed, and after the slurry in the grouting closed space and outside the steel pipe pile solidifies, a multi-section solid pile body and a plurality of reinforcement bodies outside the pile body are formed.

[0078] Therefore, this embodiment adopts the method of controlling the order and amount of grouting to the outside of the steel pipe pile, and designs the size and position of the reinforcement body according to the actual construction soil working conditions. This can not only increase the pile side friction resistance and pile end resistance, provide the vertical bearing capacity and horizontal bearing capacity of a single pile, reduce the unit bearing capacity cost to meet the design requirements, but also save a lot of grouting volume to save costs.

[0079] Other embodiments or specific implementations of the grouting method of the present invention can refer to the above-mentioned post-grouting steel pipe pile embodiments, which will not be repeated here.

[0080] The above are only preferred embodiments of the invention, and are not intended to limit the patent scope of the invention. Any equivalent structure or equivalent process transformation made using the contents of the invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the invention.

Claims

1. A post-grouting steel pipe pile, characterized in that: include: The steel pipe pile is provided with a plurality of partitions in the radial direction, and a grouting closed space is formed between two adjacent partitions; A grouting pipe is arranged along the inner side of the pile wall of the steel pipe pile and is provided with grouting outlets in a plurality of grouting closed spaces for grouting into the grouting closed spaces; An exhaust pipe is arranged along the inner side of the pile wall of the steel pipe pile and is provided with exhaust ports in a plurality of grouting closed spaces, so as to exhaust the grouting closed spaces to the outside when grouting is performed in the grouting closed spaces; The bottom of the steel pipe pile adopts a closed pile tip structure or an open pile tip structure; the pile wall of the grouting closed space and / or the inclined wall of the pile tip structure are provided with a plurality of grouting holes, and the grouting holes are used for grouting the soil outside the steel pipe pile; Wherein, each of the grouting holes is equipped with a hole plug structure, and the hole plug structure is pushed out of the grouting hole when the grouting pressure of the grouting closed space reaches a preset condition; the corresponding grouting pressure when the hole plug structure of each grouting closed space is pushed out of the grouting hole is independently set; Wherein, the hole plug structure comprises a hole plug part and a limit part which are connected to each other. When the hole plug structure is installed in the grouting hole, the hole plug part is located in the grouting hole, and the limit part is located outside the steel pipe pile; The connection tightness of the grouting holes and the plug structure in the grouting closed space is adapted to the different soil conditions outside the grouting closed space; the connection tightness of the grouting holes and the plug structure in the grouting closed space with higher softness of the external soil, higher porosity of the soil or lower friction of the soil is smaller than that of the grouting holes and the plug structure in the grouting closed space with lower softness of the external soil, lower porosity of the soil or higher friction of the soil; The tightness of the connection between the grouting hole and the plug structure is achieved by setting different connection diameters of the grouting hole and the plug structure or setting different interference fit sizes.

2. The post-grouting steel pipe pile according to claim 1, characterized in that: The partition includes a top partition and a bottom partition, and the slurry outlet and the exhaust port are arranged in a plurality of grouting closed spaces near the lower side of the top partition.

3. The post-grouting steel pipe pile according to claim 1, characterized in that: The grouting port of the grouting pipe is provided with a grouting pipe closing cap, and the air outlet of the exhaust pipe is provided with an exhaust pipe closing cap.

4. A grouting method, characterized in that: Using the post-grouting steel pipe pile according to any one of claims 1 to 3, the method comprises: S1: After the steel pipe pile sinking construction is completed, grouting is injected into the grouting pipe under the preset grouting pressure; S2: When the slurry is injected from bottom to top through the slurry outlet into a plurality of grouting closed spaces formed by partitions and flows out through the gas outlet of the exhaust pipe, the grouting is stopped; S3: closing the grouting port of the grouting pipe and the air outlet of the exhaust pipe, and forming a multi-section solid pile body after the grout in the grouting closed space solidifies; The step S3 specifically includes: S31: closing the gas outlet of the exhaust pipe, pressurizing grouting until the plug structure on the grouting hole is pushed out of the grouting hole under the pressure of the grouting liquid, and injecting the grouting liquid into the soil outside the steel pipe pile; S32: When the grouting volume and / or grouting pressure of the soil outside the steel pipe pile reaches a preset condition, the grouting is stopped, the grouting port of the grouting pipe is closed, and after the slurry in the grouting closed space and outside the steel pipe pile solidifies, a multi-section solid pile body and a plurality of reinforcement bodies outside the pile body are formed.

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