CN114319331A - Construction method of underwater pipe pile type foundation and underwater pipe pile type foundation - Google Patents

Abstract

The invention relates to the technical field of underwater pipe pile foundations, in particular to a construction method of an underwater pipe pile foundation and the underwater pipe pile foundation. The construction method of the underwater pipe pile type foundation comprises the following steps: a construction interlayer is axially arranged on the side wall of the tubular pile body, a plurality of construction openings are axially arranged on one side of the construction interlayer, which is far away from the inner cavity of the tubular pile body, and the construction openings are covered by a plugging plate; hoisting and sinking the tubular pile body at the pre-construction position to enable the tubular pile body to sink to a preset elevation; arranging blasting devices at the plurality of construction ports along the construction interlayer respectively and detonating to form a plurality of soil body cavities outside the pile; and (5) injecting cement paste into the soil body cavity through the construction opening along the construction interlayer by high pressure, and finishing construction. Through at first carrying out the explosion impact to the soil body of tubular pile body side week, through the mode of high-pressure slip casting again in to the soil body cavity that forms, can effectively strengthen the horizontal resistance of the side soil body of pile and the vertical bearing capacity of pile soil interface, reduce the risk of pile foundation to a lopsidedness.

Description

Construction method of underwater pipe pile type foundation and underwater pipe pile type foundation

Technical Field

The invention relates to the technical field of underwater pipe pile foundations, in particular to a construction method of an underwater pipe pile foundation and the underwater pipe pile foundation.

Background

With the development of offshore wind power to the deep open sea, in order to more effectively utilize offshore wind resources and improve the power generation efficiency, a large megawatt-level fan unit gradually enters research, development and application, but the whole load of the upper part of the fan can be obviously increased, the bearing capacity required by the bottom of the fan is increased, otherwise, the problem of side fall and the like can occur after the fan is installed, and the stable operation of the fan is influenced. The requirement for bearing capacity can be achieved by means of increasing the size of the offshore wind power pile foundation, but this will undoubtedly increase the production and transportation costs of the pile foundation considerably.

In order to reduce equipment cost, a post-grouting construction method is frequently adopted in a pile foundation construction method in the prior art, in the construction process, a tubular pile foundation is firstly driven into a soil body below a water body through vibration pile sinking equipment, then cement grout is injected into the bottom of the tubular pile foundation through the inner side of a tubular pile in a pressurizing mode, and concrete is extruded into the soil body, so that the strength of the soil body below the tubular pile foundation is enhanced, and the tubular pile foundation is prevented from sinking. However, in the post grouting construction process, because the density of the concrete body below the water body is higher, the diffusion volume of the concrete in the soil body is smaller, and the concrete body can filter the concrete in the process of pressurizing and injecting the concrete, so that the solid and the liquid in the concrete are separated, the strength of the concrete is greatly reduced, the bearing capacity of the pipe pile foundation is enhanced weakly, and the problems of pipe pile lateral inclination and the like still occur in the actual use process.

Disclosure of Invention

Therefore, the technical problem to be solved by the present invention is to overcome the defect that the underwater pipe pile foundation in the prior art adopts the post grouting construction method to enhance the bearing capacity of the built pipe pile foundation weakly, so as to provide a construction method of the underwater pipe pile foundation and the underwater pipe pile foundation.

In order to solve the technical problem, the invention provides a construction method of an underwater pipe pile type foundation, which comprises the following steps:

a construction interlayer is axially arranged on the side wall of the tubular pile body, a plurality of construction openings are axially arranged on one side of the construction interlayer, which is far away from the inner cavity of the tubular pile body, and the construction openings are covered by a plugging plate;

hoisting and sinking the tubular pile body at the pre-construction position to enable the tubular pile body to sink to a preset elevation;

arranging blasting devices at the plurality of construction ports along the construction interlayer respectively and detonating the blasting devices to blast the plugging plates and form soil body cavities in the soil body at the corresponding positions of the construction ports;

and injecting cement slurry into the soil body cavity through the construction opening along the construction interlayer, and finishing construction.

Optionally, before the step of injecting cement slurry into the soil cavity, the method further includes: and (4) injecting cement slurry into the soil body at the bottom of the tubular pile body through the construction interlayer to finish pile end grouting.

Optionally, the pile tip grouting step comprises: and putting the grouting pipe down to the bottom of the pipe pile body along the construction interlayer, isolating the construction interlayer at the grout outlet of the grouting pipe, and injecting cement slurry at a preset pressure through the grouting pipe.

Optionally, the step of injecting cement slurry into the soil cavity includes: and (3) arranging a grout outlet on the side wall of the grouting pipe, lowering the grouting pipe along the construction interlayer to the grout outlet and a certain construction opening, isolating two sides of the grout outlet in the axial direction of the grouting pipe in the construction interlayer, so that the grout outlet, the construction opening and the soil body cavity form an isolated closed space, and injecting cement slurry into the soil body cavity through the grouting pipe.

Optionally, the grout outlet is arranged on the side wall of the grouting pipe, and isolation air bags are arranged on two sides of the grout outlet along the axial direction of the grouting pipe; the step of isolating the two sides of the grout outlet in the axial direction of the grouting pipe in the construction interlayer comprises the following steps of: a pair of isolation airbags arranged on two sides of a grout outlet on the grouting pipe are inflated, so that the isolation airbags are expanded to completely fill the horizontal space at the position of the isolation airbag in the construction interlayer.

Optionally, the blasting device comprises a pair of isolation plates and a explosive box arranged between the pair of isolation plates; when the explosion punching devices are arranged at the plurality of construction openings, the explosive boxes are aligned with the construction openings, and the pair of isolation plates are respectively arranged at the upper side and the lower side of the construction openings.

Optionally, the step of setting a construction interlayer includes: a plurality of construction interlayers are arranged at intervals along the circumferential direction of the tubular pile body.

The invention also provides an underwater pipe pile type foundation which is built by applying the construction method of the underwater pipe pile type foundation.

Optionally, the underwater pile foundation bottom extends into the body of the earth, comprising: a tubular pile body;

the soil body cavity, the shaping is in the soil body around the tubular pile body, the soil body cavity intussuseption is filled with the cement structure, the cement structure with this body coupling of tubular pile.

Optionally, the pile body further comprises a plurality of pile side grout pulses, the pile side grout pulses extend from the soil body cavity in a divergent mode towards the direction far away from the pile body, and the pile side grout pulses and the cement structure body are connected into a whole.

The technical scheme of the invention has the following advantages:

1. the invention provides a construction method of an underwater pipe pile type foundation, which comprises the following steps: a construction interlayer is axially arranged on the side wall of the tubular pile body, a plurality of construction openings are axially arranged on one side of the construction interlayer, which is far away from the inner cavity of the tubular pile body, and the construction openings are covered by a plugging plate; hoisting and sinking the tubular pile body at the pre-construction position to enable the tubular pile body to sink to a preset elevation; arranging blasting devices at the plurality of construction ports along the construction interlayer respectively and detonating the blasting devices to blast the plugging plates and form soil body cavities in the soil body at the corresponding positions of the construction ports; and injecting cement slurry into the soil body cavity through the construction opening along the construction interlayer, and finishing construction.

Through at first carrying out the explosion impact to the soil body of tubular pile body side week, the plug plate on the construction intermediate layer is smashed to the shock wave vibration that the explosion produced, the outside soil body becomes the soil body cavity because of the impact wave, the cavity periphery soil body receives the extrusion and becomes more closely knit, then carry out the mud jacking in the soil body cavity that the stake side interval formed through the mode of high-pressure slip casting in the soil body cavity that forms again, can effectively strengthen the horizontal resistance and the vertical bearing capacity of the soil body of stake side, promote the ability that the tubular pile body resisted the horizontal deflection under side direction load and moment of flexure effect, can greatly reduced the risk of pile foundation to one side slope under the impact such as rivers wave.

2. The construction method of the underwater pipe pile type foundation provided by the invention also comprises the following steps before the step of injecting cement slurry into the soil body cavity: and (4) injecting cement slurry into the soil body at the bottom of the tubular pile body through the construction interlayer to finish pile end grouting. By injecting cement slurry into the soil body at the bottom of the tubular pile body in advance, the pile end of the tubular pile body is formed into a pile end mud jacking stone body, the soil plug effect of the tubular pile is improved, the comprehensive improvement of the bearing capacity of the tubular pile is realized, the tubular pile is prevented from settling in the construction process, the dislocation between a construction opening and a soil body cavity is avoided, the construction precision is improved, and the horizontal resistance and the vertical bearing capacity of the soil body on the pile side are effectively enhanced.

3. The construction method of the underwater pipe pile type foundation provided by the invention is characterized in that a pair of isolation air bags arranged on two sides of a grout outlet on a grouting pipe are inflated to enable the isolation air bags to be expanded to completely fill the horizontal space at the position of the isolation air bags in a construction interlayer. The horizontal space at the height of the isolation air bag is completely filled through the isolation air bag, so that the grout outlet, the construction opening and the soil body cavity form an isolated closed space, then grout is injected into the soil body cavity through the grout injection pipe, the injection pressure is increased when grout is injected, and the penetration depth of the grout in the soil body and the compaction degree of the grout in the soil body cavity can be effectively improved through pressurizing and injecting the grout.

4. The invention provides a construction method of an underwater pipe pile type foundation.A blasting device comprises a pair of isolation plates and a explosive box arranged between the pair of isolation plates; when the explosion punching devices are arranged at the plurality of construction openings, the explosive boxes are aligned with the construction openings, and the pair of isolation plates are respectively arranged at the upper side and the lower side of the construction openings. When the explosion construction forms the soil body cavity, through installing the explosive box between two division boards, when the explosive box is detonated, the ascending explosion shock wave of upper and lower direction is by the division board separation, make the shock wave only can move towards the direction of shutoff board, explode the shutoff board and destroy the back and strike formation soil body cavity in the soil body of corresponding position department, through making explosion shock wave directional motion, the closely knit degree of the soil body around the soil body cavity that the reinforcing explosion impact formed, the bearing capacity of reinforcing pile foundation side week soil body to the pile foundation.

5. The underwater pipe pile type foundation provided by the invention extends into the soil body and comprises: a tubular pile body; and the soil body cavity is formed in the soil body around the tubular pile body, a cement structure body is filled in the soil body cavity, and the cement structure body is connected with the tubular pile body. Through set up the cement structure body of being connected with tubular pile body in the soil around the tubular pile body, through the bearing capacity of reinforcing tubular pile body week side, can effectively reduce the risk that the tubular pile body takes place the side of inclining and falls.

6. The underwater pipe pile type foundation further comprises a plurality of pile side grout veins which extend from the soil body cavity in a divergent mode towards the direction far away from the pipe pile body, and the pile side grout veins and the cement structure body are connected into a whole. The pile side grout vein is extended outwards from the cement structure, so that the resistance of the whole movement of the cement structure is increased, the cement structure is prevented from settling, the cement structure can be stably connected to the periphery of the pipe pile body, and the long-term stable operation of the underwater pipe pile type foundation is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Figure 1 is a top view of a pipe pile body provided in an embodiment of the invention.

Fig. 2 is a schematic view of a pipe pile body provided in an embodiment of the present invention being driven to a predetermined elevation at the sea floor.

Fig. 3 is a schematic diagram of the steps of arranging the squib device and detonating provided in the embodiment of the present invention.

Fig. 4 is a schematic structural diagram of a squib device provided in an embodiment of the present invention.

Fig. 5 is a schematic view illustrating an operation state of an isolation airbag provided in an embodiment of the present invention.

Fig. 6 is a schematic diagram of a pile-side grouting construction step provided in an embodiment of the present invention.

Description of reference numerals: 1. channel steel; 2. a high-strength plastic panel; 3. a tubular pile body; 4. pile end grouting holes; 5. a blasting device; 6. a wire rope; 7. a soil body cavity; 8. a explosive box; 9. an explosion initiator; 10. a separator plate; 11. a mud jacking pump; 12. a stirring and slurry storing device; 13. pile side grout vein; 14. cement slurry; 15. a mud jacking pipe; 16. a pulp outlet; 17. a construction opening; 18. an isolation airbag; 19. grouting and concreting the pile end; 20. and constructing an interlayer.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In addition, the technical features involved in the different embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Example 1

As shown in fig. 1 to 6, the present embodiment provides a method for constructing an underwater pipe pile foundation, which is suitable for constructing and constructing a pipe pile foundation in water bodies such as rivers, lakes, and seas, and includes the following steps:

set up construction intermediate layer 20 along the axial at 3 lateral walls of tubular pile body, set up four construction intermediate layers 20 along 3 circumference intervals of tubular pile body. One side of the construction interlayer 20 departing from the inner cavity of the tubular pile body 3 is provided with a plurality of construction openings 17 along the axial direction, and the construction openings 17 are covered by the high-strength plastic plate 2 serving as a plugging plate. In this embodiment, at first along length direction spaced apart hole as construction mouth 17 on the web with channel-section steel 1, fix high strength plastic board 2 inboard at the rectangle hole through epoxy glue or bolted connection's mode, accomplish channel-section steel 1 and be connected the back with high strength plastic board 2, with channel-section steel 1 welding at the steel-pipe pile outer wall. The two wing plates of the channel steel 1 are welded on the outer side wall of the steel pipe pile, so that the construction interlayer 20 is formed between the channel steel 1 and the steel pipe pile.

The tubular pile body 3 with the installed construction interlayer 20 is transported to a construction machine position through a transport ship, the tubular pile body 3 is lifted, the pile is sunk through the self weight of the tubular pile body 3, and then a pile driving hammer is installed to drive the pile to a preset elevation.

Hoisting a plurality of blasting devices 5 into a construction interlayer 20 by using steel wire ropes 6, wherein each blasting device 5 comprises a pair of steel isolation plates 10 and a blasting box 8 arranged between the pair of isolation plates 10; when the blasting devices 5 are arranged at a plurality of construction openings 17, the height of the explosive box 8 is consistent with that of the construction openings 17, and the pair of isolation plates 10 are respectively arranged at the upper side and the lower side of the construction openings 17. And after the preparation work is ready, starting the explosion starter 9 to release the energy of all explosive boxes 8 in the single channel steel 1 so as to explode the plugging plate and form a soil body cavity 7 in the soil body at the position corresponding to the construction opening 17. And then taking out the residues after the pile side soil body blasting device 5 is blasted and storing the residues. Explosion and dash device 5 and pass through the hoist and mount of wire rope 6, and wire rope 6 internally arranged has the lead wire, and a plurality of explosive boxes 8 are connected gradually to lead wire one end, and explosion starter 9 is connected to the other end. When the explosion starter 9 is opened, the explosive box 8 is detonated to generate explosion shock waves, the high-strength plastic plate 2 is flushed, and the soil body cavity 7 is formed outside. A pair of partition walls 10 is provided to provide a reliable limited space for the blast impact energy to be transmitted mainly to the high strength plastic panel 2.

Before cement slurry 14 is injected into the soil body cavity 7, the cement slurry 14 is injected into the soil body at the bottom of the tubular pile body 3 through the construction interlayer 20, and pile end grouting is completed. And (3) lowering the grouting pipe 15 to the bottom of the tubular pile body 3 along the construction interlayer 20, isolating the construction interlayer 20 at the grout outlet 16 of the grouting pipe 15, and injecting the cement slurry 14 at a preset pressure through the grouting pipe 15. Specifically, a pile end grouting hole 4 for communicating the construction interlayer 20 with the inner cavity of the tubular pile body 3 is formed in one end side wall, close to the bottom, of the tubular pile body 3. The grout outlet 16 is arranged on the side wall of the grouting pipe 15, and isolating air bags 18 are arranged on two sides of the grout outlet 16 along the axial direction of the grouting pipe 15. The elevation marks are arranged on the outer surface of the grouting pipe 15, the grouting pipe 15 is firstly lowered to the pile end, the grout outlet 16 on the grouting pipe 15 is aligned with the pile end grouting hole 4, and the grout outlet 16 faces the pile end grouting hole 4. And starting the inflating device to inflate the isolating airbags 18 to expand the isolating airbags 18 on the upper side and the lower side of the grout outlet 16, after the upper isolating airbags 18 and the lower isolating airbags 18 are sealed to form a sealed space for the grout outlet 16 of the grouting pipe 15, starting the grouting pump 11 to adjust the pressure gauge to a set grouting strength, and injecting the cement slurry 14 into the soil core inside the pile end through the grouting pipe 15 to form a pile end grouting stone body 19 to finish pile end grouting. Slurry is injected into the soil core inside the pile end of the tubular pile body 3 through the pile end slurry pressing hole 4 by the slurry outlet 16 of the slurry pressing pipe 15 through high pressure to form a pile end slurry pressing stone body 19, so that the strength of the soil core is enhanced, and the bearing capacity of the pile end is improved.

Releasing air in the isolation air bags 18, lifting the grouting pipe 15 to a grout outlet 16 of the bottom channel steel 1 at the pile side, starting the inflating device again, after the upper isolation air bag 18 and the lower isolation air bag 18 are inflated, enabling the isolation air bags 18 to be expanded to completely fill the horizontal space at the positions of the isolation air bags 18 in the construction interlayer 20, enabling the grout outlet 16, the construction port 17 and the soil body cavity 7 to form isolated closed spaces, starting high-pressure grouting, enabling grout to be flushed into the soil body cavity 7 and diffused to the surrounding soil body, and stopping grouting when the grouting speed is sharply reduced. And repeating the step of lifting the mud jacking pipe 15 to enable the mud outlet 16 to sequentially correspond to the soil body cavities 7 at different heights until the mud jacking construction of all the pile sides is finished. The grouting construction process in the plurality of construction interlayers 20 can be carried out simultaneously or independently, and the specific construction mode can be determined according to the construction site condition. When the grouting is performed, the cement slurry 14 in the stirring and storing device 12 is injected into the slurry outlet 16 of the grouting pipe 15 through the slurry suction pipe and the grouting conveying pipe by the pressure generated by the grouting pump 11. Annular isolation airbags 18 are arranged above and below a grout outlet 16 of the grouting pipe 15, and the isolation airbags 18 are inflated before grouting to form a closed space, so that cement slurry 14 can smoothly enter a soil body cavity 7 formed by explosion impact under the action of high pressure, and simultaneously enter soil bodies on the periphery of the soil body cavity 7 in a penetrating, compacting or splitting mode to form irregular pile side grout veins 13 which develop longitudinally and transversely.

The invention has proposed the lifting technology of bearing capacity of back mud jacking suitable for offshore wind power steel pipe pile explosion impact, through increasing and exploding the device 5, the impact wave that the explosion produces shakes the shutoff plastic slab on the broken channel steel 1, the outside soil body is formed into the soil body cavity 7 because of the impact wave, the peripheral soil body of cavity is squeezed and become more closely knit, reduce the pore ratio of the soil body, carry on the mud jacking in the soil body cavity 7 that the side interval of pile forms through the way of high-pressure slip casting, can promote the horizontal resistance and vertical bearing capacity of the side soil body of pile integrally; in addition, the grouting holes arranged near the pile ends can reinforce the soil core inside the tubular pile body 3, so that the soil plug effect of the steel pipe pile is further improved, and the comprehensive improvement of the bearing capacity of the tubular pile body 3 is realized.

As an alternative embodiment, when the wall thickness of the tubular pile body 3 satisfies the design strength, the construction interlayer may be directly molded in the side wall of the tubular pile body 3 when the tubular pile body 3 is molded.

As an alternative embodiment, when the inner diameter of the tubular pile body 3 meets the construction requirement, the construction interlayer may be formed by welding the channel steel 1 on the inner side wall of the tubular pile body 3, and the construction opening 17 is reserved on the side wall when the tubular pile body 3 is formed or the construction opening 17 is formed by cutting at the corresponding position after the construction of the construction interlayer is completed.

Example 2

The embodiment provides an underwater pipe pile type foundation which is built by applying the construction method of the underwater pipe pile type foundation in embodiment 1.

Underwater pipe pile formula basis bottom extends to in the soil body, includes: tubular pile body and soil body cavity. The soil body cavity, the shaping is in the soil body around the tubular pile body, the soil body cavity intussuseption is filled with the cement structure, the cement structure with this body coupling of tubular pile. The pile side slurry pulse extension pipe is characterized by further comprising a plurality of pile side slurry pulses, wherein the pile side slurry pulses extend from the soil body cavity towards the direction far away from the tubular pile body in a divergent mode, and the pile side slurry pulses are connected with the cement structure into a whole. The side grout vein is installed by extending the cement structure body outwards, so that the resistance of the whole movement of the cement structure body is increased, the cement structure body is prevented from settling, the cement structure body can be stably connected to the periphery of the tubular pile body, and the long-term stable operation of the underwater tubular pile type foundation is ensured. The inner cavity at the bottom of the tubular pile body is also provided with a pile end grouting stone body to enhance the soil plug effect. Through setting up soil body cavity, cement structure, stake side pulse thick liquid and stake end mud jacking calculus body, realize that tubular pile body level and vertical bearing capacity are synthesized and are promoted, can greatly reduced tubular pile body take place the risk that the slope side fell in the use.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (10)

1. A construction method of an underwater pipe pile type foundation is characterized by comprising the following steps:

a construction interlayer (20) is axially arranged on the side wall of the tubular pile body (3), a plurality of construction openings (17) are axially arranged on one side of the construction interlayer (20) departing from the inner cavity of the tubular pile body (3), and the construction openings (17) are covered by a plugging plate;

hoisting and sinking the tubular pile body (3) at the pre-construction position to enable the tubular pile body (3) to sink to a preset elevation;

arranging blasting devices (5) at a plurality of construction ports (17) along the construction interlayer (20) respectively and detonating to blast the plugging plate and form soil body cavities (7) in soil bodies at corresponding positions of the construction ports (17);

and (3) injecting cement slurry (14) into the soil body cavity (7) through the construction opening (17) along the construction interlayer (20), and finishing construction.

2. The method of constructing a underwater pile foundation as claimed in claim 1, further comprising, before the step of injecting cement slurry (14) into the soil cavity (7): and (3) injecting cement slurry (14) into the soil body at the bottom of the tubular pile body (3) through the construction interlayer (20) to finish pile end grouting.

3. The method of constructing an underwater pile foundation of claim 2, wherein the pile-end grouting step includes: and (3) putting the grouting pipe (15) down to the bottom of the pipe pile body (3) along the construction interlayer (20), isolating the construction interlayer (20) at the grout outlet (16) of the grouting pipe (15), and injecting grout (14) at a preset pressure through the grouting pipe (15).

4. A method of constructing an underwater pile foundation according to any of claims 1 to 3, wherein the step of injecting grout (14) into the soil cavity (7) comprises: a grout outlet (16) is formed in the side wall of the grouting pipe (15), the grouting pipe (15) is placed to the grout outlet (16) and a certain construction opening (17) along the construction interlayer (20), two sides of the grout outlet (16) in the construction interlayer (20) along the axial direction of the grouting pipe (15) are isolated, isolated closed spaces are formed by the grout outlet (16), the construction opening (17) and the soil body cavity (7), and grout (14) is injected into the soil body cavity (7) through the grouting pipe (15).

5. The method of constructing a underwater pile foundation according to claim 4, wherein isolating airbags (18) are installed at both sides of the grout outlet (16) in the axial direction of the grout pipe (15); the step of isolating the two sides of the grout outlet (16) axially upwards along the grouting pipe (15) in the construction interlayer (20) comprises the following steps: a pair of isolation airbags (18) arranged at two sides of a grout outlet (16) on the grouting pipe (15) are inflated, so that the isolation airbags (18) are expanded to completely fill the horizontal space at the position of the isolation airbags (18) in the construction interlayer (20).

6. A method of constructing an underwater pile foundation according to any one of claims 1 to 3, wherein the blasting device (5) comprises a pair of partition plates (10) and a cartridge (8) provided between the pair of partition plates (10); when the blasting and impacting devices (5) are arranged at the plurality of construction openings (17), the explosive boxes (8) are aligned with the construction openings (17), and the pair of isolation plates (10) are respectively arranged at the upper side and the lower side of the construction openings (17).

7. The method of constructing an underwater pile foundation according to any one of claims 1 to 3, wherein the step of providing a construction interlayer (20) includes: a plurality of construction interlayers (20) are arranged along the circumferential direction of the tubular pile body (3) at intervals.

8. An underwater pile foundation constructed by applying the construction method of an underwater pile foundation as recited in any one of claims 1 to 7.

9. The underwater pile foundation of claim 8, wherein the bottom portion extends into the body of earth, comprising:

a tubular pile body (3); soil body cavity (7), the shaping is in the soil body around tubular pile body (3), the intussuseption of soil body cavity (7) is filled with the cement structure, the cement structure with tubular pile body (3) are connected.

10. A subsea pipe pile foundation according to claim 9, characterised in that it further comprises a plurality of pile side grout veins (13) extending divergently from the soil cavity (7) towards a direction away from the pipe pile body (3), the pile side grout veins (13) being integrally connected with the cement structure.

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