Movable flap expanding bottom anti-pulling steel pipe pile and construction method

Abstract

The application provides a movable flap expanding bottom anti-pulling steel pipe pile and a construction method. The pipe pile body is a cylindrical hollow rod. A plurality of movable flaps are arranged around the outer periphery of the lower end of the pipe pile body and are hinged. The movable flaps have at least a first angle position of being folded relative to the pipe pile body and a second angle position of being unfolded relative to the pipe pile body. A traction mechanism includes traction ropes connected to the movable flaps one by one to adjust the unfolding angle of the movable flaps. A flap locking mechanism is arranged at the lower end of the pipe pile body and locks the movable flaps when the traction ropes adjust the movable flaps of the pipe pile to the second angle position. The movable flap expanding bottom anti-pulling steel pipe pile can flexibly adjust the unfolding and folding of the movable flaps through the cooperation of the pipe pile body, the movable flaps, the traction mechanism (traction ropes) and the flap locking mechanism without special hydraulic expanding bottom equipment, and the structure is simple and the construction is convenient, which greatly reduces the construction cost.

Description

Technical Field

[0001] This invention relates to the field of deep foundation technology, and in particular to movable flap-type expanded-base anti-uplift steel pipe piles and their construction methods. Background Technology

[0002] As the demand for urban infrastructure gradually shifts towards complex working conditions, high load-bearing capacity, and convenient and efficient construction, steel pipe piles have become a core foundation component in fields such as architecture, bridges, and marine engineering due to their high compressive strength, strong adaptability, and high construction efficiency.

[0003] One current technique for strengthening the pull-out resistance of steel pipe piles is base enlargement, which increases the bearing area at the pile end to improve end resistance. However, this method relies on specialized hydraulic base enlargement equipment, which is complex, costly, and has poor adaptability. Another approach is to use a flap-type base enlargement structure, utilizing an airbag to drive the flap's deployment. However, the airbag is prone to aging or damage, and is easily blocked by mud and sand in mud-wall drilling conditions, resulting in low reliability. Therefore, there is an urgent need for a steel pipe pile base enlargement pull-out resistance technology that is simple in structure, convenient to construct, cost-controllable, and has high pull-out reliability to meet the engineering needs of small and medium-diameter steel pipe piles. Summary of the Invention

[0004] The main objective of this invention is to provide a movable flap-type expanded-base anti-pull-out steel pipe pile and its construction method, so as to solve the technical problem that existing expanded-base technologies rely on dedicated hydraulic expanded-base equipment or use airbags for driving, resulting in low reliability.

[0005] To achieve the above objectives, the present invention provides a movable flap-type expanded-base anti-uplift steel pipe pile, comprising:

[0006] The pipe pile body is a cylindrical hollow rod.

[0007] Multiple movable flaps surround the lower periphery of the pipe pile body and are hinged thereto. Each movable flap has at least a first angle position that is retracted relative to the pipe pile body and a second angle position that is open relative to the pipe pile body.

[0008] The traction mechanism includes traction ropes that are connected one-to-one with the movable flaps to adjust the opening angle of the movable flaps. The traction ropes are located inside or outside the pipe pile body and are longer than the length of the pipe pile body. A flap locking mechanism is located at the lower end of the pipe pile body and locks the movable flaps when the traction ropes adjust the movable flaps of the pipe pile to the second angle position.

[0009] According to an embodiment of this application, the traction rope is disposed inside the pipe of the pipe pile body, with its first end connected to the movable flap and its second end extending out of the upper end of the pipe pile body.

[0010] According to an embodiment of this application, the pipe pile body has a guide wheel assembly that corresponds one-to-one with the traction rope. The guide wheel assembly includes a plurality of guide wheels distributed along the height direction of the pipe pile body, and the traction rope is wound around the corresponding plurality of guide wheels in sequence.

[0011] According to an embodiment of this application, the traction mechanism further includes a traction device, a sensor, and a rope locking mechanism. The traction device is connected to the second end, and both the sensor and the rope locking mechanism are connected to the traction rope.

[0012] According to an embodiment of this application, the flap locking mechanism includes a movable pin, a locking cylinder, and a helical compression spring. The locking cylinder is fixedly connected to the pipe pile body, and the movable pin is slidably assembled inside the locking cylinder and sleeved on the helical compression spring. A retaining seat is formed at the upper end of the movable flap, and the retaining seat has an abutment surface and a recess. In the first angle position, the movable pin abuts against the abutment surface. In the second angle position, the movable pin is released and falls into the recess.

[0013] According to an embodiment of this application, the card holder has a guide ramp between the abutment surface and the recess.

[0014] According to an embodiment of this application, the wall surface of the recess on the side away from the abutment surface is an inclined surface, which fits against the cylindrical surface of the movable pin at the second corner position.

[0015] According to an embodiment of this application, the lower end of the pipe pile body has a flap hinge seat, and the movable flap is hinged to the flap hinge seat by a pin.

[0016] According to the embodiments of this application, in the first corner position, the plurality of movable flaps close together, forming a streamlined shape, and sealing the opening at the lower end of the pipe pile body.

[0017] This application also provides a construction method for the above-mentioned movable flap-type expanded-base anti-uplift steel pipe pile, including:

[0018] Drilling creates pile holes.

[0019] With the movable flap in the first corner position, the pipe pile body is lowered to the designed elevation of the pile hole.

[0020] Pulling with traction ropes, multiple movable flaps simultaneously open outward to their second corner position and are secured by a flap locking mechanism. Concrete is then poured into the pipe pile body to form an integral enlarged base structure.

[0021] The aforementioned movable flap-type expanded-base anti-pull-out steel pipe pile, through the coordinated operation of the pipe pile body, movable flap, traction mechanism (traction rope) and flap locking mechanism, does not require special hydraulic expanded-base equipment. The opening and closing of the movable flap can be flexibly adjusted by the traction rope alone. The structure is simple, the construction is convenient, the construction cost is greatly reduced, and it is suitable for the engineering needs of small and medium diameter steel pipe piles. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the retracted state of the movable flap-type expanded-base anti-pull-out steel pipe pile according to one embodiment of this application.

[0024] Figure 2 This is a schematic diagram of the outward expansion state of the active flap-type expanded base anti-pull-out steel pipe pile according to one embodiment of this application.

[0025] Figure 3 This is a schematic diagram of the internal structure of the pipe pile body according to one embodiment of this application;

[0026] Figure 4 This is a schematic diagram of the movable flap located at the first corner position according to one embodiment of this application;

[0027] Figure 5 This is a schematic diagram of the movable flap located at the second corner position according to one embodiment of this application;

[0028] Figure 6 This is a schematic diagram of the movable flap in one embodiment of this application, located at the first corner position and cooperating with the flap locking mechanism;

[0029] Figure 7 This is a schematic diagram of the movable flap in the second corner position and its cooperation with the flap locking mechanism according to one embodiment of this application.

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

[0031] 100. Pipe pile body; 200. Movable flap; 300. Traction mechanism; 400. Flap locking mechanism;

[0032] 110. Guide wheel;

[0033] 210. Flip-plate hinge seat; 220. Locking seat; 221. Abutting surface; 222. Recess; 223. Guide slope;

[0034] 310. Towing rope; 320. Rope locking mechanism;

[0035] 410. Movable pin; 420. Locking cylinder; 430. Helical compression spring. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] It should be noted that all directional indicators (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0038] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0039] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. 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 claimed by the present invention.

[0040] An embodiment of this application provides a movable flap 200-inch expanded-base anti-uplift steel pipe pile, referring to... Figure 1 and Figure 2 It includes the pipe pile body 100, multiple movable flaps 200, a traction mechanism 300, and a flap locking mechanism 400.

[0041] The pipe pile body 100 is a cylindrical hollow rod. Multiple movable flaps 200 surround the lower periphery of the pipe pile body 100 and are hinged thereto. Each movable flap 200 has at least a first angle position that is closed relative to the pipe pile body 100 and a second angle position that is open relative to the pipe pile body 100. A traction mechanism 300 includes traction ropes 310 connected one-to-one with each movable flap 200 to adjust the opening angle of the movable flaps 200. The traction ropes 310 are disposed inside or outside the pipe pile body 100 and are longer than the length of the pipe pile body 100. A flap locking mechanism 400 is disposed at the lower end of the pipe pile body 100 and locks the movable flaps 200 when the traction ropes 310 adjust the movable flaps 200 to the second angle position.

[0042] In some embodiments, the pipe pile body 100 is made of high-strength steel pipe and has a cylindrical hollow structure. The outer diameter is set according to engineering requirements to ensure sufficient compressive and tensile strength and structural stability. The length of the pipe pile body 100 is determined according to the construction design elevation. Multiple movable flaps 200 are evenly arranged around its lower outer perimeter. The number of movable flaps 200 is 3 to 6, preferably 4, to ensure uniform stress distribution and to form a stable expanded base structure after unfolding.

[0043] The movable flap 200 is made of steel plate, and its shape is adapted to the outer circumference of the pipe pile body 100. In its initial state (first angle position), it is in a retracted state (first angle position) and fits snugly against the outer circumference of the pipe pile body 100. In its open state (second angle position), it tilts outward. The angle between the movable flap 200 and the axis of the pipe pile body 100 can be adjusted via the traction rope 310 to reach the second angle position. For example, the second angle is 30° to 60°. The movable flap 200 is hinged to the pipe pile body 100 to ensure flexible switching without jamming.

[0044] The traction rope 310 can be made of high-strength steel wire rope, which has sufficient tensile strength to prevent breakage during pulling. The length of the traction rope 310 is greater than the length of the pipe pile body 100, ensuring that its second end can extend to the upper end of the pipe pile body 100, facilitating operation by construction personnel. The traction rope 310 can be installed inside or outside the pipe, with priority given to installation inside the pipe, which can avoid wear and blockage by mud and sand during construction, thereby improving service life and operational reliability.

[0045] The flap locking mechanism 400 is located at the lower end of the pipe pile body 100 and corresponds one-to-one with the movable flap 200. It is used to lock the movable flap 200 after it is opened to the second corner position to prevent it from being reset due to external force during concrete pouring or later use, thereby ensuring the stability of the expanded base structure and thus ensuring the pull-out bearing capacity of the steel pipe pile.

[0046] The aforementioned movable flap 200 expanded-base anti-uplift steel pipe pile, through the coordinated operation of the pipe pile body 100, movable flap 200, traction mechanism 300 (traction rope 310) and flap locking mechanism 400, does not require special hydraulic expanded-base equipment. The opening and closing of the movable flap 200 can be flexibly adjusted by the traction rope 310 alone. The structure is simple, the construction is convenient, the construction cost is greatly reduced, and it is suitable for the engineering needs of small and medium diameter steel pipe piles.

[0047] In some embodiments, refer to Figure 1 and Figure 2 The traction rope 310 is installed inside the pipe of the pipe pile body 100, with its first end connected to the movable flap 200 and its second end extending out of the upper end of the pipe pile body 100.

[0048] The traction rope 310 is installed inside the pipe pile body 100, which can effectively avoid the wear and blockage of mud and sand, and at the same time avoid the friction between the traction rope 310 and the pile hole wall, ensuring a smooth traction process. The first end of the traction rope 310 is fixedly connected to the upper end of the movable flap 200 by means of buckle or welding, and the connection is firm and there is no looseness. The second end extends out of the upper end of the pipe pile body 100, which is convenient for connection with the traction equipment to realize the pulling and adjustment of the movable flap 200.

[0049] In some embodiments, refer to Figure 1 , Figure 2 and Figure 3 The pipe pile body 100 has a set of guide wheels 110 that are arranged one-to-one with the traction rope 310. The set of guide wheels 110 includes a plurality of guide wheels 110 distributed along the height direction of the pipe pile body 100, and the traction rope 310 is wound around the corresponding plurality of guide wheels 110 in sequence.

[0050] The guide wheels 110 are made of stainless steel to prevent rust and extend service life. Each guide wheel set includes 2-4 guide wheels 110, evenly distributed along the height of the pipe pile body 100. The axis of the guide wheel 110 is perpendicular to the axis of the pipe pile body 100, and its groove is adapted to the traction rope 310 to guide the direction of the traction rope 310, reduce friction between the traction rope 310 and the inner wall of the pipe pile body 100, ensure smooth traction, and at the same time, make the multiple traction ropes 310 evenly stressed, so that multiple movable flaps 200 can open and close synchronously, avoiding the problem of inconsistent flap opening angles. In some specific embodiments, the pipe pile body 100 has ear plates for installing the guide wheels 110.

[0051] In some embodiments, refer to Figure 1 and Figure 2The traction mechanism 300 further includes a traction device, a sensor, and a rope locking mechanism 320; the traction device is connected to the second end, and the sensor and the rope locking mechanism 320 are both connected to the traction rope 310.

[0052] The traction device can be a winch or a hand-operated hoist. The appropriate power is selected based on the pipe pile size and the weight of the flap 200 to provide traction force, pulling the traction rope 310 to adjust the opening angle of the movable flap 200. The sensor is a tension sensor, used to detect the tension value of the traction rope 310 in real time, ensuring the traction rope 310 reaches the preset traction stress, thereby allowing the movable flap 200 to reach the target angle, such as the second angle position. Furthermore, it can prevent excessive tension from causing the traction rope 310 to break or the flap to be damaged; the tension value is controlled within 60% to 80% of the rated tensile strength of the traction rope 310.

[0053] The rope locking mechanism 320 is a locking clip or buckle used to lock the traction rope 310 after the movable flap 200 is opened to a preset angle, preventing the traction rope 310 from loosening. It forms a double lock with the flap locking mechanism 400, further improving stability.

[0054] In some embodiments, refer to Figure 4 , Figure 5 , Figure 6 and Figure 7 The flap locking mechanism 400 includes a movable pin 410, a locking cylinder 420, and a spiral compression spring 430. The locking cylinder 420 is fixedly connected to the pipe pile body 100. The movable pin 410 is slidably assembled inside the locking cylinder 420 and sleeved on the spiral compression spring 430. The upper end of the movable flap 200 forms a retaining seat 220, which has an abutting surface 221 and a recess 222. In the first corner position, the movable pin 410 abuts against the abutting surface 221. In the second corner position, the movable pin 410 is released and falls into the recess 222.

[0055] For example, the locking cylinder 420 is made of steel pipe and is fixedly connected to the lower end of the pipe pile body 100 by welding, with its axis perpendicular to the axis of the pipe pile body 100. The movable pin 410 has a cylindrical structure with a diameter that matches the inner diameter of the locking cylinder 420, and can slide along the axis inside the locking cylinder 420. A helical compression spring 430 is sleeved on the movable pin 410, with one end abutting against the bottom of the locking cylinder 420 and the other end abutting against the boss in the middle of the movable pin 410. Under normal conditions, it is in a compressed state, pushing the movable pin 410 outward.

[0056] The mounting base 220 at the upper end of the movable flap 200 is integrally formed with the movable flap 200. The abutment surface 221 is flat and is adapted to the end of the movable pin 410. The size of the recess 222 is adapted to the end of the movable pin 410 to accommodate the end of the movable pin 410 for locking. When the movable flap 200 is in the first corner position (closed state), the abutment surface 221 of the mounting base 220 presses the movable pin 410, causing the movable pin 410 to compress the spiral compression spring 430 and retract into the locking cylinder 420. When the movable flap 200 rotates to the second corner position (open state) under the pull of the traction rope 310, the pressure of the abutment surface 221 on the movable pin 410 disappears, the spiral compression spring 430 resets, and pushes the movable pin 410 outward to fall into the recess 222 of the mounting base 220, thereby locking the movable flap 200.

[0057] In some embodiments, refer to Figure 6 and Figure 7 The card holder 220 has a guide slope 223 between the abutment surface 221 and the recess 222. The guide slope 223 is a smooth slope with an inclination angle of 45° to 60°. During the rotation of the movable flap 200 from the first corner position to the second corner position, it can guide the movable pin 410 to slide smoothly, avoid the movable pin 410 from getting stuck with the card holder 220, ensure that the movable flap 200 can rotate smoothly to the preset angle, and at the same time facilitate the movable pin 410 to fall accurately into the recess 222 under the action of the helical compression spring 430, forming a one-way limit and locking the flap unfolding angle.

[0058] In some embodiments, refer to Figure 6 and Figure 7 The wall surface of the recess 222 on the side away from the abutment surface 221 is inclined, and at the second corner position, it fits against the cylindrical surface of the movable pin 410. This inclined surface fits tightly against the cylindrical surface of the movable pin 410, which can form a one-way mechanical limit on the movable pin 410, preventing the movable pin 410 from falling out of the recess 222, that is, preventing the flap from folding inward under the action of external force, and further improving the locking reliability.

[0059] In one specific embodiment, the retaining seat 220 is made of Q355 steel, and the movable pin 410 is made of 40Cr steel with a rounded guide surface at the head for easy sliding and locking. The locking cylinder 420 is made of Q235 steel, with an inner diameter that fits the movable pin 410 with a clearance, and its end is welded to the inner wall of the steel pipe pile. The helical compression spring 430 is made of 65Mn spring steel, pre-loaded and installed inside the locking cylinder 420, with an initial preload of N to ensure reliable ejection of the movable pin 410.

[0060] In some embodiments, refer to Figure 1 and Figure 2The lower end of the pipe pile body 100 has a flap hinge seat 210, and the movable flap 200 is hinged to the flap hinge seat 210 by a pin.

[0061] The flap hinge seat 210 is a U-shaped structure welded from steel plates, which is fixedly connected to the lower outer periphery of the pipe pile body 100, and the number is the same as that of the movable flap 200. The upper end of the movable flap 200 is provided with a hinge hole. The pin passes through the hinge hole of the flap hinge seat 210 and the movable flap 200 to realize the hinge connection between the movable flap 200 and the pipe pile body 100. The pin is made of stainless steel and the surface is coated with grease to ensure that the movable flap 200 rotates flexibly and reduces wear.

[0062] In some embodiments, refer to Figure 1 and Figure 2 At the first corner position, the multiple movable flaps 200 close together, forming a streamlined shape, thus sealing the opening at the lower end of the pipe pile body 100. After the movable flaps 200 are closed, their outer circumferential surfaces are flush with the outer circumferential surfaces of the pipe pile body 100, and their streamlined shape reduces friction between the pipe pile body 100 and the pile hole wall and mud during the lowering process, facilitating lowering. At the same time, the closed movable flaps 200 can completely seal the opening at the lower end of the pipe pile body 100, preventing mud and slurry from entering the pipe pile body 100 during the lowering process, preventing blockage inside the pipe, and facilitating subsequent concrete pouring.

[0063] This application embodiment also provides a construction method for the above-mentioned movable flap 200 expanded base anti-uplift steel pipe pile, characterized in that it includes:

[0064] S100: Drilling to form a pile hole;

[0065] S200: With the movable flap 200 in the first corner position, the pipe pile body 100 is lowered to the design elevation of the pile hole;

[0066] S300: Pulled by the traction rope 310, multiple movable flaps 200 are simultaneously opened outward to the second corner position and fixed by the flap locking mechanism 400; concrete is poured into the pipe pile body 100 to form an integral expanded bottom structure.

[0067] This construction method is simple and easy to operate, requiring no complicated procedures. The enlarged base construction can be completed by drilling, lowering the pipe pile, opening the flap, and pouring concrete, which greatly improves construction efficiency and reduces construction costs. At the same time, after the concrete is poured, it forms an integral enlarged base structure with the pipe pile body 100 and the movable flap 200, which further improves the pull-out reliability and structural integrity of the steel pipe pile, and is suitable for a variety of complex construction conditions.

[0068] In some embodiments, the specific implementation process of the construction method is as follows:

[0069] 1. Drilling to form pile holes: According to the engineering design requirements, drilling equipment (such as auger drilling rig or rotary drilling rig) is used to drill holes at designated locations to form pile holes; the diameter of the pile hole is slightly larger than the outer diameter of the pipe pile body by 100, and the depth of the pile hole is determined according to the design elevation.

[0070] 2. Lowering the pipe pile: With the movable flap 200 in the first corner position (closed state), check the closing status of the movable flap 200, the connection reliability of the traction mechanism 300, and the flexibility of the flap locking mechanism 400; lift the pipe pile body 100 and slowly lower it into the pile hole, keeping the pipe pile body 100 vertical during the lowering process to avoid tilting, while utilizing the streamlined structure of the movable flap 200 to reduce the lowering resistance; after the pipe pile body 100 is lowered to the design elevation, fix the pipe pile body 100 to prevent it from shifting or sinking.

[0071] 3. Opening and locking of movable flaps 200: Connect the traction device to the second end of the traction rope 310, start the traction device, and slowly pull the traction rope 310 to drive multiple movable flaps 200 to rotate outward synchronously; monitor the tension value of the traction rope 310 in real time through the tension sensor. When the preset traction stress is reached, when the corresponding movable flap 200 rotates to the second angle position (preset opening angle), the movable pin 410 of the flap locking mechanism 400 falls into the recess 222 of the card seat 220 under the action of the spiral compression spring 430, thereby locking the movable flap 200; at this time, the traction rope 310 is locked by the rope locking mechanism 320, forming a double lock to ensure that the movable flap 200 is stable in the second angle position.

[0072] 4. Concrete Pouring: Concrete is poured into the pipe pile body 100. The concrete is C30~C40 high-strength concrete. During the pouring process, the concrete is poured slowly to avoid excessive impact force that could cause the movable flap 200 to shift. The concrete is poured to the lower opening of the pipe pile body 100 and fills the gap between the movable flap 200 and the pile hole wall to form an integral enlarged bottom structure. After the pouring is completed, the concrete is cured for no less than 7 days to ensure that the concrete strength meets the design requirements, so that the concrete is firmly bonded to the pipe pile body 100 and the movable flap 200, thereby improving the overall pull-out bearing capacity.

[0073] 5. Subsequent procedures: After the concrete curing is completed, remove the traction equipment, rope locking mechanism 320 and other auxiliary components, and complete the construction of the movable flap 200 enlarged base anti-pull-out steel pipe pile; if multiple steel pipe piles need to work together, repeat the above steps to complete the construction of all steel pipe piles, ensuring that the enlarged base structure of each steel pipe pile is consistent and the stress is uniform.

[0074] During construction, the opening angle of the movable flap 200 can be adjusted by adjusting the pulling distance of the traction rope 310 according to the actual needs of the project, thereby adjusting the enlarged bottom area to adapt to different pull-out bearing capacity requirements. At the same time, the entire construction process does not require special hydraulic enlarged bottom equipment, making it convenient to operate, efficient, and significantly reducing construction costs. It is suitable for various complex construction conditions of small and medium diameter steel pipe piles.

[0075] The above technical solutions of the present invention are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A movable flap-type expanded-base anti-pull-out steel pipe pile, characterized in that, include: The pipe pile body is a cylindrical hollow rod; Multiple movable flaps surround the outer periphery of the lower end of the pipe pile body and are hinged thereto. Each movable flap has at least a first angle position that is retracted relative to the pipe pile body and a second angle position that is open relative to the pipe pile body. The traction mechanism includes traction ropes that are connected one-to-one with the movable flaps to adjust the opening angle of the movable flaps; the traction ropes are located inside or outside the pipe body of the pipe pile and are longer than the length of the pipe pile body. The flap locking mechanism is located at the lower end of the pipe pile body. When the traction rope adjusts the movable flap of the pipe pile to the second corner position, it locks the movable flap.

2. The movable flap-type expanded-base anti-pull-out steel pipe pile according to claim 1, characterized in that, The traction rope is installed inside the pipe of the pipe pile body, with its first end connected to the movable flap and its second end extending out of the upper end of the pipe pile body.

3. The movable flap-type expanded-base anti-pull-out steel pipe pile according to claim 2, characterized in that, The pipe pile body has a guide wheel assembly that corresponds one-to-one with the traction rope. The guide wheel assembly includes multiple guide wheels distributed along the height direction of the pipe pile body, and the traction rope is wound around the corresponding multiple guide wheels in sequence.

4. The movable flap-type expanded-base anti-pull-out steel pipe pile according to claim 2, characterized in that, The traction mechanism further includes a traction device, a sensor, and a rope locking mechanism; the traction device is connected to the second end, and the sensor and the rope locking mechanism are both connected to the traction rope.

5. The movable flap-type expanded-base anti-pull-out steel pipe pile according to claim 1, characterized in that, The flap locking mechanism includes a movable pin, a locking cylinder, and a helical compression spring; the locking cylinder is fixedly connected to the pipe pile body, and the movable pin is slidably assembled inside the locking cylinder and sleeved on the helical compression spring. The upper end of the movable flap forms a retaining seat, which has a contact surface and a recess; in the first corner position, the movable pin abuts against the contact surface; in the second corner position, the movable pin is released and falls into the recess.

6. The movable flap-type expanded-base anti-pull-out steel pipe pile according to claim 5, characterized in that, The card holder has a guide ramp between the abutment surface and the recess.

7. The movable flap-type expanded-base anti-pull-out steel pipe pile according to claim 6, characterized in that, The wall surface of the recess on the side away from the abutment surface is inclined, and at the second corner position, it fits against the cylindrical surface of the movable pin.

8. The movable flap-type expanded-base anti-pull-out steel pipe pile according to claim 1, characterized in that, The lower end of the pipe pile body has a flap hinge seat, and the movable flap is hinged to the flap hinge seat by a pin.

9. The movable flap-type expanded-base anti-uplift steel pipe pile according to any one of claims 1 to 8, characterized in that, At the first corner position, the multiple movable flaps close together, forming a streamlined shape, thus sealing off the opening at the lower end of the pipe pile body.

10. A construction method for a movable flap-type expanded-base anti-uplift steel pipe pile according to any one of claims 1 to 9, characterized in that, include: Drilling is used to form pile holes; With the movable flap in the first corner position, the pipe pile body is lowered to the design elevation of the pile hole; By pulling with traction ropes, multiple movable flaps simultaneously open outward to the second corner position and are fixed by flap locking mechanism; Concrete is poured into the body of the pipe pile to form an integral enlarged base structure.

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