High-bearing-capacity concrete-filled steel tube pile and construction method thereof

Abstract

The invention discloses a high-bearing-capacity concrete-filled steel tube pile and a construction method thereof.The concrete-filled steel tube pile comprises a steel tube pile body, an arc-shaped thin-wall steel plate, blades and temporary connecting pieces of the steel tube pile body and the arc-shaped thin-wall steel plate, and blade telescopic holes are formed in the steel tube pile body in the pile length direction; the arc-shaped thin-wall steel plate is arranged in the steel pipe pile, the blades are arranged on the outer surface of the arc-shaped thin-wall steel plate, and the blades are embedded into the blade telescopic holes; the steel pipe pile body and the arc-shaped thin-wall steel plate temporary connecting piece are arranged at the top of the steel pipe pile body, and the steel pipe pile body and the arc-shaped thin-wall steel plate are connected through the steel pipe pile body and the arc-shaped thin-wall steel plate temporary connecting piece. Compared with a traditional screw pile, due to the design of the telescopic blades, cutting disturbance to a soil body in the construction process of the traditional screw pile is reduced, and the vertical bearing capacity is increased; concrete is poured into the pile body, the concrete and the steel pipe pile body work together, the horizontal load resisting capacity of the pile foundation is enhanced, and the horizontal bearing capacity of the pile foundation is improved.

Description

Technical Field

[0001] The present invention belongs to the field of pile foundation engineering, relates to a pile foundation, and specifically relates to a high-bearing-capacity concrete-filled steel tube pile and its construction method. Background Art

[0002] The pile foundation is one of the important foundation forms of offshore wind turbines, and its bearing capacity is composed of the side friction resistance of the pile body and the end resistance of the pile. To reduce the cost of the foundation part, screw piles have begun to replace traditional pile foundations and are applied to offshore wind power projects. It consists of a steel pipe pile body and spiral blades welded to the pile body. The blades increase the contact area between the pile foundation and the soil. Therefore, its bearing capacity has been significantly improved. The screw pile foundation usually adopts a construction method of applying torque at the pile top to screw the pile into the foundation soil. However, during the process of screwing such pile foundations into the foundation, the blades will have a significant cutting effect on the soil around the pile, resulting in a reduction in the bearing capacity of the pile foundation. This phenomenon is particularly significant in cohesive soil foundations. In addition, due to economic considerations, the wall thickness of screw piles is usually small, resulting in a small horizontal bearing capacity and weak seismic performance, which limits its application in some important projects. Summary of the Invention

[0003] In order to solve the problem of the reduction in the bearing capacity of the pile foundation caused by the disturbance of the soil during the construction of traditional screw piles, the present invention provides a high-bearing-capacity concrete-filled steel tube pile and its construction method. Compared with traditional screw piles, the design of retractable blades reduces the cutting disturbance of the soil during the construction of traditional screw piles and increases the vertical bearing capacity; concrete is poured into the pile body, and the concrete and the steel pipe pile body work together to enhance the ability of the pile foundation to resist horizontal loads and improve the horizontal bearing capacity of the pile foundation.

[0004] The object of the present invention is achieved through the following technical solutions:

[0005] A high-bearing-capacity concrete-filled steel tube pile includes a steel pipe pile body, an arc-shaped thin-walled steel plate, blades, and a temporary connector between the steel pipe pile body and the arc-shaped thin-walled steel plate, wherein:

[0006] The steel pipe pile body is provided with blade expansion and contraction holes along the pile length direction;

[0007] The arc-shaped thin-walled steel plate is arranged inside the steel pipe pile, and blades are arranged on the outer surface of the arc-shaped thin-walled steel plate;

[0008] The number of blade expansion and contraction holes is equal to the number of blades and the positions correspond to each other, and the blades are embedded in the blade expansion and contraction holes;

[0009] The temporary connector between the steel pipe pile body and the arc-shaped thin-walled steel plate is arranged at the top of the steel pipe pile body, and the steel pipe pile body and the arc-shaped thin-walled steel plate are connected through the temporary connector between the steel pipe pile body and the arc-shaped thin-walled steel plate.

[0010] A construction method for the above high - bearing - capacity concrete - filled steel tube pile includes the following steps:

[0011] Step (1): According to the setting - out result of the pile design drawing, determine the position of each pile - driving location for the pile foundation construction to ensure the correct pile position;

[0012] Step (2): Position the pile - driving or pile - pressing equipment of the pile driver;

[0013] Step (3): Feed the pile into the guide rod and adjust the verticality of the pile;

[0014] Step (4): Use the pile - driving or pile - pressing equipment of the pile driver to drive or press the steel tube pile body into the designed depth;

[0015] Step (5): Feed a solid cylinder with a diameter slightly smaller than the inner diameter of the pile into the guide rod. The solid cylinder has a tapered tip at the bottom. Align the solid cylinder with the center of the high - bearing - capacity concrete - filled steel tube pile and release the temporary connection between the steel tube pile body and the thin - walled arc - shaped steel plate;

[0016] Step (6): Press the solid cylinder into the interior of the steel tube pile body. During the pressing process, the solid cylinder continuously squeezes the thin - walled arc - shaped steel plate, and squeezes the blades through the blade expansion holes on the steel tube pile body into the surrounding soil of the pile to achieve the full extension of the blades, and then pull out the solid cylinder for reuse;

[0017] Step (7): After completing the above steps, pour concrete into the pile;

[0018] Step (8): After the construction is completed, shift to construct the next high - bearing - capacity concrete - filled steel tube pile and re - execute steps (2) to (7).

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. Due to the design of the retractable blades, the high - bearing - capacity concrete - filled steel tube pile of the present invention avoids the cutting and disturbance of the blades to the surrounding soil of the pile during the pile foundation construction process.

[0021] 2. The pile foundation is constructed by driving or pressing, which belongs to the category of displacement piles, effectively improving the side friction resistance of the pile.

[0022] 3. After the blades extend outwards and insert into the soil layer, the contact area between the pile body and the soil is increased, improving the bearing capacity of the pile foundation.

[0023] 4. Pouring concrete into the interior of the steel tube pile body can effectively fix the blades; the concrete and the steel tube pile body work together, increasing the stiffness of the pile foundation and effectively improving its horizontal bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the high - bearing - capacity concrete - filled steel tube pile;

[0025] Figure 2 Schematic diagram for comparison after the blades of the high - bearing - capacity concrete - filled steel tube pile extend outwards;

[0026] Figure 3 Thin - walled arc - shaped steel plate and blades fixed on the outside;

[0027] Figure 4 Top view of the concrete - filled steel tube pile with bearing capacity;

[0028] Figure 5 Top view for comparison after the blades of the high - bearing - capacity concrete - filled steel tube pile with blades extend outwards;

[0029] In the figure, 1 is the steel tube pile body; 12 is the conical pile bottom; 2 is the thin - walled arc - shaped steel plate; 3 are the blades welded on the thin - walled arc - shaped steel plate; 31 are the blade expansion holes; 4 is the temporary connector between the steel tube pile body and the thin - walled arc - shaped steel plate; 41 are the threaded holes. Specific implementation mode

[0030] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be covered by the protection scope of the present invention.

[0031] The present invention provides a high - bearing - capacity concrete - filled steel tube pile, as Figures 1-5 shown, the concrete - filled steel tube pile includes a steel tube pile body 1, a thin - walled arc - shaped steel plate 2, blades 3 welded on the thin - walled arc - shaped steel plate, and a temporary connector 4 between the steel tube pile body and the thin - walled arc - shaped steel plate.

[0032] As Figure 2 shown, the steel tube pile body 1 is provided with blade expansion holes 31 along the pile length direction, a conical pile bottom 12 is arranged at the bottom of the steel tube pile body 1, the number of the blade expansion holes 31 is equal to that of the blades 3 and the positions correspond to each other. Before pile foundation construction, the blades 3 are embedded at the blade expansion holes 31 and it is ensured that the outer ends of the blades do not protrude outside the steel tube pile body 1.

[0033] As Figure 1 、 Figure 2 and Figure 3 shown, the thin - walled arc - shaped steel plate 2 is arranged inside the steel tube pile body 1, the outer surface of the thin - walled arc - shaped steel plate 2 is provided with blades 3, and the thin - walled arc - shaped steel plate 2 and the blades 3 are fixedly connected by welding.

[0034] As Figure 1 、 Figure 3 and Figure 4As shown in the figure, the temporary connector 4 between the steel pipe pile body and the thin-walled arc-shaped steel plate is located at the top of the steel pipe pile body 1. Threaded holes 41 are provided at the tops of both the steel pipe pile body 1 and the thin-walled arc-shaped steel plate 2. The temporary connector 4 between the steel pipe pile body and the thin-walled arc-shaped steel plate connects the steel pipe pile body 1 and the thin-walled arc-shaped steel plate 2 together through the threaded holes 41.

[0035] The present invention also provides a construction method for the above high-bearing-capacity concrete-filled steel pipe pile, and the specific steps are as follows:

[0036] (1) According to the pile layout results of the pile design drawing, determine the position of each pile to be driven for pile foundation construction to ensure the correct pile position;

[0037] (2) Position the pile driving (pressing) equipment of the pile driver;

[0038] (3) Feed the pile into the guide rod and adjust the verticality of the pile;

[0039] (4) Use the pile driving (pressing) equipment to drive (press) the steel pipe pile body into the designed depth;

[0040] (5) Feed a solid cylinder with a diameter slightly smaller than the inner diameter of the pile into the guide rod. The solid cylinder has a tapered tip at the bottom. Align the solid cylinder with the center of the high-bearing-capacity concrete-filled steel pipe pile and release the temporary connector between the steel pipe pile body and the thin-walled arc-shaped steel plate;

[0041] (6) Press the solid cylinder into the inside of the steel pipe pile body. During the pressing process, the solid cylinder continuously squeezes the thin-walled arc-shaped steel plate, and squeezes the blades into the surrounding soil of the pile through the blade expansion holes on the steel pipe pile body to achieve the full extension of the blades, and then pull out the solid cylinder for reuse;

[0042] (7) After completing the above steps, pour concrete inside the pile to fix the arc-shaped thin-walled steel plate and the blades;

[0043] (8) After the construction is completed, shift to construct the next high-bearing-capacity concrete-filled steel pipe pile and re-execute the above steps (2) to (7).

Claims

1. A high-bearing capacity steel tube concrete pile, characterized in that The steel tube concrete pile comprises a steel tube pile body, an arc-shaped thin-walled steel plate, blades, and a temporary connection piece between the steel tube pile body and the arc-shaped thin-walled steel plate, wherein: The steel pipe pile body is provided with blade expansion holes along the pile length direction; The arc-shaped thin-walled steel plate is arranged inside the steel pipe pile, and blades are arranged on the outer surface of the arc-shaped thin-walled steel plate; The blade expansion and contraction holes are equal in number to the blades, and their positions correspond to each other, and the blades are embedded in the blade expansion and contraction holes; The temporary connecting piece between the steel pipe pile body and the arc-shaped thin-walled steel plate is arranged on the top of the steel pipe pile body, and the steel pipe pile body and the arc-shaped thin-walled steel plate are connected through the temporary connecting piece between the steel pipe pile body and the arc-shaped thin-walled steel plate.

2. The high-bearing capacity steel tube concrete pile according to claim 1, characterized in that A conical pile bottom is arranged at the bottom of the steel pipe pile body.

3. The high bearing capacity steel tube concrete pile according to claim 1, characterized in that The thin-walled arc-shaped steel plate is fixedly connected to the blades by welding.

4. The high-bearing capacity steel tube concrete pile according to claim 1, characterized in that The tops of the steel pipe pile body and the thin-walled arc-shaped steel plate are both provided with threaded holes, and the temporary connecting piece of the steel pipe pile body and the thin-walled arc-shaped steel plate connects the steel pipe pile body and the thin-walled arc-shaped steel plate together through the threaded holes.

5. A construction method for high-bearing capacity steel tube concrete piles according to any one of claims 1 to 4, characterized in that The method comprises the following steps: Step (1) according to the result of laying out the pile design drawing, determine the location of each pile foundation construction position where piles need to be driven, and ensure that the pile position is correct; Step (2) the pile driver or pile pressing equipment is in place; Step (3) sending the pile into the guide rod and adjusting the verticality of the pile; Step (4) using a pile driver or pile pressing equipment to drive or press the steel pipe pile body into the designed depth; Step (5) inserting a solid cylinder with a pile diameter slightly smaller than the inner diameter of the pile into the guide rod, the solid cylinder having a cone tip at the bottom, aligning the solid cylinder with the center of the high-bearing capacity steel tube concrete pile, and releasing the temporary connection between the steel tube pile body and the thin-walled arc steel plate; Step (6) pressing the solid cylinder into the steel pipe pile body, during which the solid cylinder continuously squeezes the thin-walled arc-shaped steel plate, and squeezes the blades into the soil around the pile through the blade expansion holes on the steel pipe pile body to achieve full extension of the blades, and then pulling out the solid cylinder for reuse; Step (7) After completing the above steps, pour concrete inside the pile; After the construction of step (8) is completed, the next high-bearing-capacity steel tube concrete pile is moved and constructed, and steps (2) to (7) are executed again.

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