A construction method of a static pressure pile sinking device using a middle-through method

Abstract

The present invention relates to a static pressure pile sinking device and method using a center-through method, comprising a prestressed pipe pile, a column frame, a hollow drill rod and a drill bit arranged at the end of the drill rod, wherein an inner guide tube is arranged in the inner cavity of the first section of the pipe pile, and the inner guide tube is connected to the pipe pile by bolts. When there is a thick silty clay layer or clay layer between the ground and the sand layer, an inner guide tube is arranged in the pipe pile to prevent the silty clay or clay from entering the cavity of the pipe pile and blocking the inner wall cavity thereof. The center-through method effectively destroys the mechanical self-locking phenomenon in the sand layer, and the drilling and drawing of holes and static pressure pile sinking in the whole process are carried out synchronously, and the two construction equipments are connected as one and cannot be separated, and the drilling and drawing of holes does not need to be moved and the holes are drawn in the cavity of the prestressed pipe pile, and the soil layer around the pile body will not be disturbed when the holes are drawn, so that the bearing capacity of the construction pipe pile and the constructed pipe piles near the pile will not be affected, until the pile end of the prestressed pipe pile penetrates the dense sand layer and reaches the designed elevation and pile length.

Description

Technical Field

[0001] The invention relates to the technical field of pipe pile construction, and in particular to a construction method of a static pressure pile sinking device using a center-through method. Background Art

[0002] Prestressed concrete pipe piles have been widely used in building (structure) pile foundation projects due to their high pile strength, fast construction speed, good on-site civilized construction conditions, and easy detection. With the popularization of prestressed pipe piles, complex strata that are difficult to penetrate are often encountered during the construction of prestressed pipe piles, such as dense sand layers, gravel layers, etc.

[0003] In order to solve the difficulties and obstacles in the construction of prestressed pipe piles, auxiliary hole construction is now mostly used. The conventional drilling and punching process has problems such as large hole diameter, slow construction speed, mud wall protection making on-site civilized construction management difficult, and high hole construction cost; when long spiral sand layer areas are used for hole construction, it is easy to cause hole collapse due to the adverse influence of groundwater level. During the drilling process, the spiral blades of the long spiral drill cut the soil around the pile, causing disturbance, destroying the original soil structure, reducing the strength, and affecting the bearing capacity of the pipe piles constructed after the hole construction and the pipe piles constructed near the piles, and the expected purpose cannot be achieved.

[0004] According to theoretical analysis, during the pile sinking process, the friction resistance around the pile should gradually increase with the depth of the pile. However, the actual situation is that when the pile enters the sand layer, the friction resistance will instantly increase from 100T to 500T or even greater, making it difficult to sink the pile. However, the pile can be pulled out by lifting it at the construction site, indicating that the difficulty in sinking the pile into the sand layer is not caused by the friction resistance on the side of the pile body, but by the pile end resistance. According to calculations, there will be such a large end resistance only when it enters the rock layer, and the end of the pile in the on-site construction only enters the sand layer.

[0005] The above situation shows that the prestressed pipe pile is constructed in the dense sand layer area. The pipe pile is a soil-squeezing pile. When the pile is pressed into the sand layer, under the intense squeezing and compacting effect of the pile-pressing force, the dense sand layer around the pile end forms a relatively sealed ring, resulting in the diffuse calcium nodules in the sand layer being unable to move around the pile body and can only deflect during the pile-pressing process. The calcium nodules accumulate more and more, gradually changing the friction angle of the friction resistance, and finally forming a mechanical self-locking phenomenon similar to the sand and gravel cushion structure, making it difficult to sink the pile (such as Figure 1 As shown). However, this self-locking phenomenon is not stable. If the pile driving force is determined only according to the self-locking phenomenon in actual construction, this self-locking phenomenon may gradually open over time, which will cause the pile bearing capacity to fail to meet the design requirements, endangering the use and safety of the building.

[0006] Some machines can move according to their structural analysis, but due to the existence of friction, they cannot move no matter how much the driving force increases. This is called mechanical self-locking. The essence of mechanical self-locking is that the effective component of the driving force acting on the component is always smaller than the maximum friction in the same direction caused by it.

[0007] like Figure 2 As shown in the figure, component a is on component b, and the external force acting on component a is F, and the angle between it and the normal line of the contact surface is β. If the friction coefficient between the two components is f, then f=tgφ. The friction resistance generated by the external force F is Ff ba =fFcosβ=Fcosβtgφ, the horizontal component of F is Fsinβ. When Fsinβ< <Ff ba When , no matter how F increases, it will not cause component 2 to move. This phenomenon is called self-locking. At this time, β≤φ.

[0008] A large amount of practice has proved that the difficulty in constructing prestressed pipe piles in dense sand layers is the manifestation of the mechanical self-locking phenomenon in sand layer geology. Summary of the invention

[0009] In order to seek new processes and methods that are faster and more efficient, save investment, speed up construction progress, ensure construction quality, and solve the problems existing in the prior art, the present invention provides a method for internal dredging that has high hole-drawing effectiveness and can effectively destroy the self-locking phenomenon in the sand layer, namely, the middle-pass method, and a static pressure pile sinking device and method using the middle-pass method. The invention solves the problems of pile length being too short, pile cutting, drawing holes, and single pile bearing capacity being unable to be guaranteed, which are caused by the mechanical self-locking phenomenon similar to the sand and gravel cushion structure formed by the sand layer soil near the pile end under the intense squeezing and compacting force of the pile driving force, resulting in the pile driving failing to reach the designed depth, so that the prestressed pipe pile can smoothly reach the designed depth.

[0010] One aspect of the present invention provides a construction method of a static pressure pile driving device using a center-through method, the device comprising a prestressed pipe pile, a column frame, a hollow drill rod and a drill bit arranged at the end of the drill rod, an inner guide tube is arranged in the inner cavity of the first section of the pipe pile, and the inner guide tube is connected to the prestressed pipe pile by bolts. When there is a thick silty clay layer or clay layer between the ground and the sand layer, an inner guide tube is arranged in the prestressed pipe pile to prevent the silty clay and clay from entering the cavity of the prestressed pipe pile and blocking the inner wall cavity thereof. The pile driving device of the present invention has the advantages of high hole-guiding effectiveness and can effectively destroy the self-locking phenomenon in the sand layer.

[0011] When it is impossible to continue sinking piles due to mechanical self-locking, use the power head and drill rod installed on the column frame to sink into the cavity of the inner wall of the prestressed pipe pile, and then use high-pressure jetting, large-flow water injection, and air injection to drill the hole to the vicinity of the bottom of the pile end before continuing to sink the pile downwards statically. The drill rod length is adjustable, and the power head and drill rod for drilling and guiding holes can rotate horizontally. The boring process does not need to be extended in sections, which does not hinder the static pressure construction of the prestressed pipe pile. The static pressure pile sinking is followed up while drilling and guiding holes to ensure the effectiveness of the boring. The drill bit is always kept 45-55 cm longer than the bottom of the prestressed pipe pile. The hard layer is cut by high-pressure jetting, large-flow water injection, and air jetting at the bottom of the drill rod, so that the large-flow water carries sand and soil out of the cavity of the inner wall of the prestressed pipe pile, thereby destroying the mechanical self-locking phenomenon in the sand layer soil, so that the prestressed pipe pile continues to sink smoothly.

[0012] The drilling and static pressure pile driving of the whole process are carried out simultaneously, and the two kinds of construction equipment are connected as one. The drilling and drawing of holes do not need to be moved and the holes are drawn in the cavity of the prestressed pipe piles. The soil layer around the pile body will not be disturbed during the drilling process, so as not to affect the bearing capacity of the prestressed pipe piles under construction and the prestressed pipe piles constructed near the piles, until the pile end of the prestressed pipe pile penetrates the dense sand layer and reaches the designed elevation and pile length.

[0013] Preferably, a flange is welded to the top of the inner conduit, and a threaded hole is opened on the flange to connect with the top of the prestressed pipe pile by bolts. When the prestressed pipe pile is pressed into the sand layer, the bolts are loosened and the inner conduit is lifted out.

[0014] In any of the above schemes, it is preferred that the inner conduit is a seamless steel pipe, the length of which is equal to the length of the prestressed pipe pile; and the outer diameter of the inner conduit matches the diameter of the cavity inside the prestressed pipe pile.

[0015] In any of the above solutions, preferably, the top and bottom of the hollow drill rod are provided with joint screws. When the pile length exceeds 20 meters, the drill rod is lengthened by connecting the hollow drill rods together with bolts.

[0016] In any of the above schemes, preferably, the top of the hollow drill rod is connected to the power head; and a drill bit is provided at the lower end of the hollow drill rod.

[0017] In any of the above schemes, it is preferred that three concentric tubes are arranged in the hollow drill rod, namely a high-jet tube, a large-flow water injection tube and an air injection tube. Drilling and high-pressure jetting can quickly cut the soil. If there is a silty clay layer in the sand layer, drilling and high-pressure jetting can make the lead hole pass smoothly, increasing the efficiency of the lead hole and pile driving construction. The high-jet tube, the large-flow water injection tube and the air injection tube are set to achieve large-flow water injection, and the air injection carries the cut sand layer and discharges it smoothly along the cavity of the prestressed pipe pile, and then discharges it to the designated location of the site through drainage.

[0018] In any of the above solutions, preferably, the lower end of the drill bit is 45-55 cm lower than the lower end of the prestressed pipe pile.

[0019] In any of the above schemes, it is preferred that the top interface of the hollow drill pipe includes a high-pressure injection interface, a large-flow water injection interface and an air injection pipe interface.

[0020] In any of the above solutions, preferably, the top interface of the hollow drill rod is connected to the background equipment.

[0021] In any of the above schemes, it is preferred that the background equipment includes high-pressure injection equipment, large-flow water injection equipment and large-flow gas injection equipment.

[0022] In any of the above schemes, it is preferred that a power head horizontal rotation device or a horizontal rotation device is provided on the top of the column frame to prevent the power head and the drill rod from hindering the prestressed pipe pile from entering the static pile driver clamp.

[0023] In any of the above schemes, it is preferred that the column frame is fixed on the static pressure pile driver platform at a height of 30 meters, so that the drill rod does not need to be repeatedly disassembled and installed, thereby improving the working effect; and a static pressure pile driver clamp is provided on the static pressure pile driver platform.

[0024] A construction method of a static pile sinking device using a center-through method comprises the following steps:

[0025] Step 1: When there is a thick silty clay layer or clay layer between the ground and the sand layer, prevent the silty clay or clay from entering the cavity of the prestressed pipe pile and blocking the cavity of the inner wall of the prestressed pipe pile. When the first section of the pipe pile sinks, first set an inner conduit in the cavity of the inner wall of the prestressed pipe pile. The length of the inner conduit is equal to the length of the prestressed pipe pile, and the outer diameter of the inner conduit is equal to the diameter of the cavity inside the prestressed pipe pile. The top welding flange of the inner conduit is connected with the inherent threaded hole at the top of the prestressed pipe pile by bolts. When the prestressed pipe pile is pressed into the sand layer, loosen the bolts on the flange, and use the crane provided by the static pressure pile to lift out the inner conduit;

[0026] Step 2: Turn on the drilling power device, and the power head drives the hollow drill rod to insert into the cavity of the prestressed pipe pile to drill the hole; while drilling the hole, press the pile, and keep the drill bit of the first section of the hollow drill rod 45-55 cm lower than the bottom of the prestressed pipe pile. During the drilling process, high-pressure jetting, large-flow water injection and gas injection are continuously performed;

[0027] Step 3: When the first section of the pile is pressed to the welding position, lift the hollow drill rod to the horizontal rotation device position of the column frame, and rotate the power head and drill rod horizontally 90 degrees;

[0028] Step 4: Use a crane to hoist in the second section of the pile, lower it and align it with the first section of the pile, weld it and fix it, then sink the hollow drill rod into the cavity of the prestressed pile and continue to perform high-pressure jetting, high-flow water injection and gas injection, while drilling and guiding the hole and pressing the pile;

[0029] Step 5: Repeat steps 3 and 4 until the prestressed pipe pile reaches the designed pile length and elevation, and the drill rod for drilling the guide hole is removed. The entire pile construction procedure is completed. If there is no thick silty clay layer or clay layer between the ground and the sand layer, the construction can start from step 2.

[0030] The construction method of the static pressure pile driving device adopting the center-through method of the present invention solves the problems of pile length being too short, pile cutting, hole drawing, and single pile bearing capacity being unable to be guaranteed due to the mechanical self-locking phenomenon similar to the sand and gravel cushion structure formed by the sand layer soil near the pile end under the severe squeezing and compacting action of the pile driving force, which causes the pile driving to fail to reach the designed depth, thereby enabling the prestressed pipe pile to smoothly reach the designed depth. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the mechanical self-locking phenomenon process of sand layer geological formation in the prior art.

[0032] Figure 2 This is a theoretical analysis diagram of the mechanical self-locking phenomenon in the prior art.

[0033] Figure 3 It is a schematic structural diagram of a static pressure pile driving device using the center-through method according to the present invention.

[0034] Figure 4 The static pressure pile sinking device using the middle-through method according to the present invention Figure 1 A schematic diagram of a prestressed pipe pile with a built-in guide tube in the illustrated embodiment.

[0035] Figure 5 The static pressure pile sinking device using the middle-through method according to the present invention Figure 4 Top view of the illustrated embodiment. DETAILED DESCRIPTION

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other embodiments can be obtained based on these drawings without creative work.

[0037] like Figure 3-Figure 5As shown, a schematic diagram of the structure of a preferred embodiment of a static pressure pile driving device using the center-through method according to the present invention. A construction method of a static pressure pile driving device using the center-through method according to the present invention, the device comprises a prestressed pipe pile 2, a column frame 10, a hollow drill rod 11 and a drill bit 14 arranged at the end of the drill rod, an inner guide tube 3 is arranged in the inner cavity of the prestressed pipe pile 2, and the inner guide tube is connected to the prestressed pipe pile 2 by bolts. The inner guide tube 3 is arranged in the prestressed pipe pile 2 to prevent silty clay or clay from entering the cavity of the prestressed pipe pile 2 and clogging the inner wall cavity thereof. The pile driving device of the present invention has the advantages of high hole-guiding effectiveness and can effectively destroy the self-locking phenomenon in the sand layer.

[0038] When the pile cannot be sunk any further due to the mechanical self-locking phenomenon, the power head 5 and the drill rod 11 installed on the column frame 10 are used to sink into the inner wall cavity of the prestressed pipe pile 2, and then high-pressure jetting, large-flow water injection, and air injection are used to drill the hole to the vicinity of the bottom of the pile end before continuing to sink the pile downward with static pressure. The length of the drill rod 11 is adjustable, and the power head 5 and the drill rod 11 for drilling and guiding holes can be rotated horizontally. The boring process does not need to be extended in sections, and the static pressure construction of the prestressed pipe pile is not hindered. The static pressure pile sinking is followed up while drilling and guiding holes, which ensures the effectiveness of boring. The drill bit 14 is always kept 45-55 cm longer than the bottom of the prestressed pipe pile 2. The hard layer is cut by high-pressure jetting, large-flow water injection, and air jetting of the drill bit 14 at the bottom of the drill rod 11, so that the large-flow water carries sand and soil and is discharged from the inner wall cavity of the prestressed pipe pile, thereby destroying the mechanical self-locking phenomenon in the sand layer soil, so that the prestressed pipe pile continues to sink smoothly.

[0039] The drilling and static pressure pile driving of the whole process are carried out simultaneously, and the two kinds of construction equipment are connected as one. The drilling and drawing of holes do not need to be moved and the holes are drawn in the cavity of the prestressed pipe piles. The soil layer around the pile body will not be disturbed during the drilling process, so as not to affect the bearing capacity of the prestressed pipe piles under construction and the prestressed pipe piles constructed near the piles, until the pile end of the prestressed pipe pile penetrates the dense sand layer and reaches the designed elevation and pile length.

[0040] The construction method of the static pressure pile driving device adopting the center-through method of the present invention solves the problems of pile length being too short, pile cutting, hole drawing, and single pile bearing capacity being unable to be guaranteed due to the mechanical self-locking phenomenon similar to the sand and gravel cushion structure formed by the sand layer soil near the pile end under the severe squeezing and compacting action of the pile driving force, which causes the pile driving to fail to reach the designed depth, thereby enabling the prestressed pipe pile to smoothly reach the designed depth.

[0041] In this embodiment, the top end of the inner conduit 3 is welded with a flange 1 (see Figure 4 , Figure 5 As shown in FIG. 1 ), the flange is provided with threaded holes 4 and is connected to the top of the prestressed pipe pile 2 by bolts. When the prestressed pipe pile 2 is pressed into the sand layer, the bolts are loosened and the inner conduit 3 is lifted out.

[0042] In this embodiment, the inner conduit 3 is a seamless steel pipe, and its length is equal to that of the prestressed pipe pile 2 ; the outer diameter of the inner conduit 3 matches the diameter of the inner cavity of the prestressed pipe pile 2 .

[0043] In this embodiment, the top and bottom of the hollow drill rod 11 are provided with joint screws. When the pile length exceeds 20 meters, the hollow drill rods are connected together by bolts to lengthen the drill rods.

[0044] In this embodiment, the top of the hollow drill rod 11 is connected to the power head 5 ; the lower end of the hollow drill rod 11 is provided with a drill bit 14 .

[0045] In this embodiment, three concentric pipes are arranged in the hollow drill rod 11, namely, a high-jet pipe, a large-flow water injection pipe and an air injection pipe. Drilling and high-pressure jetting can quickly cut the soil. If there is a silty clay layer in the sand layer, drilling and high-pressure jetting can make the lead hole pass smoothly, increasing the efficiency of the lead hole and pile pressing construction. The high-jet pipe, the large-flow water injection pipe and the air injection pipe are set to realize the large-flow water injection and air injection to carry the cut sand layer smoothly along the cavity of the prestressed pipe pile 2, and then discharge it to the designated location of the site through drainage.

[0046] In this embodiment, the lower end of the drill bit 14 is 45-55 cm lower than the lower end of the prestressed pipe pile 2 .

[0047] In this embodiment, the top interface of the hollow drill rod 11 includes a high-pressure injection interface 6 , a large-flow water injection interface 7 and an air injection pipe interface 8 .

[0048] In this embodiment, the top interface of the hollow drill rod 11 is connected to the background equipment 13 .

[0049] In this embodiment, the background equipment 13 includes high-pressure injection equipment, large-flow water injection equipment and large-flow gas injection equipment.

[0050] In this embodiment, a power head horizontal rotation device or a horizontal rotation device 9 is provided on the top of the column frame 10 to prevent the power head 5 and the drill rod 11 from hindering the prestressed pipe pile 2 from entering the static pile driver fixture 12.

[0051] In this embodiment, the column frame 10 is fixed on the static pile driver platform at a height of 30 meters, so that the drill rod 11 does not need to be repeatedly disassembled and installed, thereby improving the working effect; a static pile driver clamp 12 is provided on the static pile driver platform.

[0052] The construction method of the static pile sinking device using the middle-through method of the present invention comprises the following steps:

[0053] The first step: when there is a thick silty clay layer or clay layer between the ground and the sand layer, prevent the silty clay or clay from entering the cavity of the prestressed pipe pile 2 and blocking the inner wall cavity of the prestressed pipe pile 2. When the first section of the pipe pile sinks, first set the inner conduit 3 in the inner wall cavity of the prestressed pipe pile 2. The length of the inner conduit 3 is equal to the length of the prestressed pipe pile 2. The outer diameter of the inner conduit 3 matches the diameter of the inner cavity of the prestressed pipe pile 2. The top welding flange 1 of the inner conduit 3 is connected with the inherent threaded hole 4 at the top of the prestressed pipe pile 2 by bolts. When the prestressed pipe pile 2 is pressed into the sand layer, loosen the bolts on the flange 1, and use the static pressure pile self-contained crane to lift out the inner conduit 3.

[0054] Step 2: Start the drilling power device, and the power head 5 drives the hollow drill rod 11 to insert into the cavity of the prestressed pipe pile 2 to drill the hole; while drilling the hole, press the pile, and keep the drill bit 14 of the first section of the hollow drill rod 11 always 45-55 cm lower than the bottom of the prestressed pipe pile 2. During the drilling process, high-pressure injection, large-flow water injection and gas injection are continuously performed;

[0055] Step 3: When the first section of the pile is pressed to the welding position, the hollow drill rod 11 is lifted to the position of the horizontal rotating device 9 of the column frame 10, and the power head 5 and the drill rod 11 are horizontally rotated 90 degrees;

[0056] Step 4: Use a crane to hoist in the second section of the pile, lower the second section of the pile and align it with the first section of the pile, weld and fix it, then sink the hollow drill rod 11 into the cavity of the prestressed pile and continue to perform high-pressure injection, large-flow water injection and gas injection, while drilling and guiding the hole and pressing the pile;

[0057] Step 5: Repeat steps 3 and 4 until the prestressed pipe pile reaches the designed pile length and elevation, and the drill rod for drilling the guide hole is removed. The entire pile construction procedure is completed. If there is no thick silty clay layer or clay layer between the ground and the sand layer, the construction can start from step 2.

[0058] It is not difficult for a person skilled in the art to understand that the construction method of the static pressure pile sinking device using the middle-through method of the present invention includes any combination of the various parts in this specification. Due to space limitations and to make the specification concise, these combinations are not described in detail one by one here, but after reading this specification, the scope of the present invention consisting of any combination of the various parts constituting this specification is self-evident.

Claims

1. A construction method of a static pressure pile sinking device using a center-through method, the device comprising a prestressed pipe pile (2), a column frame (10), a hollow drill rod (11) and a drill bit (14) arranged at the end of the drill rod, characterized in that: An inner conduit (3) is provided in the inner cavity of the prestressed pipe pile (2), and the inner conduit is connected to the prestressed pipe pile (2) by bolts; the top of the hollow drill rod (11) is connected to the power head (5); the lower end of the hollow drill rod (11) is provided with a drill bit (14); the top of the column frame (10) is provided with a power head horizontal rotation device or a horizontal rotation device (9); the method comprises the following steps: Step 1: When there is a silty clay layer or clay layer between the ground and the sand layer, when the first section of the pipe pile is sunk, an inner guide tube (3) is first arranged in the inner wall cavity of the prestressed pipe pile (2), and a flange (1) is welded at the top of the inner guide tube (3) and connected with a threaded hole inherent in the top of the prestressed pipe pile (2) by bolts. When the prestressed pipe pile (2) is pressed into the sand layer, the bolts on the flange (1) are loosened, and the inner guide tube (3) is lifted out by the crane provided by the static pressure pile; Step 2: Start the drilling power device, and the power head (5) drives the hollow drill rod (11) to be inserted into the cavity of the prestressed pipe pile (2) to drill the hole; while drilling the hole, the pile is pressed, and the drill bit (14) of the first section of the hollow drill rod (11) is always kept 45-55 cm lower than the bottom of the prestressed pipe pile (2). During the drilling process, high-pressure jetting, large-flow water injection and gas injection are continuously performed; Step 3: When the first section of the pile is pressed to the welding position, the hollow drill rod (11) is lifted to the position of the horizontal rotating device (9) of the column frame (10), and the power head (5) and the drill rod (11) are horizontally rotated 90 degrees; Step 4: Use a crane to hoist in the second section of the pipe pile, lower the second section of the pipe pile, align it with the first section of the pipe pile, and then weld it to fix it. Then, sink the hollow drill rod (11) into the cavity of the pipe pile and continue to perform high-pressure jetting, large-flow water injection and gas injection, while drilling and guiding the hole and pressing the pile; Step 5: Repeat steps 3 and 4 until the pile reaches the designed length and elevation, and then remove the drill rod from the guide hole. The entire pile construction procedure is completed. If there is no silty clay layer or clay layer between the ground and the sand layer, construction can start from step 2.

2. The construction method of the static pile sinking device using the center-through method as claimed in claim 1, characterized in that: A flange (1) is welded to the top end of the inner guide tube (3), and a threaded hole (4) is provided on the flange and is connected to the top end of the prestressed pipe pile (2) by means of bolts.

3. The construction method of the static pile sinking device using the center-through method as claimed in claim 2 is characterized by: The inner conduit (3) is made of a seamless steel pipe, and its length is equal to the length of the prestressed pipe pile (2); the outer diameter of the inner conduit (3) matches the diameter of the inner cavity of the prestressed pipe pile (2).

4. The construction method of the static pile sinking device using the center-through method as claimed in claim 2 or 3, characterized in that: The top and bottom of the hollow drill rod (11) are provided with joint screw ports.

5. The construction method of the static pile sinking device using the center-through method as claimed in claim 2, characterized in that: Three concentric pipes are arranged inside the hollow drill rod (11), which are a high-injection pipe, a large-flow water injection pipe and a gas injection pipe.

6. The construction method of the static pile sinking device using the center-through method as claimed in claim 2, characterized in that: The lower end of the drill bit (14) is 45-55 cm lower than the lower end of the prestressed pipe pile (2).

7. The construction method of the static pile sinking device using the center-through method as claimed in claim 2, characterized in that: The top interface of the hollow drill rod (11) comprises a high-pressure injection interface (6), a large-flow water injection interface (7) and an air injection pipe interface (8).

8. The construction method of the static pile sinking device using the center-through method as claimed in claim 2, characterized in that: The top interface of the hollow drill rod (11) is connected to the backstage equipment (13).

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