Precast enlarged head structure for achieving base expansion after precast hollow pipe pile installation.

Abstract

This invention provides a precast enlarged head structure for achieving base expansion after the installation of precast hollow pipe piles. [Solution] The precast enlarged head structure includes an end plate 101, an upper wing hemisphere 201, a collision column, a plurality of fan-shaped columnar expansion wings 301, and a plurality of L-shaped suspension plates 304. The end plate is fixedly attached to a hollow circular pile, the upper wing hemisphere is detachably attached to the end plate, the plurality of L-shaped suspension plates are fixedly attached to the end plate, and the plurality of expansion wings are hinged to correspond to the L-shaped suspension plates and are completely retracted inward. After being temporarily fixed in the retracted state with cable ties, they are driven into the ground together with the hollow circular pile. After being driven into the ground, the collision column repeatedly collides with the upper wing hemisphere in the inner bore of the hollow circular pile. The upper wing hemisphere, after detaching from the end plate, collides with the expansion wings, piercing the cable ties and opening outward until the support wings are fully extended. Subsequently, a uniform collision force is applied downward from the upper end surface of the hollow circular pile by the collision block and other structures.

Description

Technical Field

[0001] The present invention belongs to the technical field of pile foundation construction, and particularly relates to a precast enlarged head structure for realizing an enlarged bottom after driving a precast hollow pipe pile.

Background Art

[0002] In pile foundation construction, precast piles are widely used in various construction projects because of their good pile integrity, short construction period, and excellent economy. In order to improve the bearing capacity of a single pile and reduce settlement, the enlarged bottom pile construction method is often used. The principle of the enlarged bottom pile construction method is to form an enlarged head at the pile tip, increase the load area at the pile tip, and thus significantly improve the tip bearing capacity of the pile. At present, the main technical means for enlarging the pile tip on site is mechanical hole expansion.

[0003] However, since the mechanical hole expansion device has a complex structure and is often inconvenient to operate in deep hole soil layers, when performing an enlarged bottom, it is difficult to control the shape of the enlarged head. As a result, the increase range of the load area at the pile tip by the enlarged head is limited.

Summary of the Invention

Problems to be Solved by the Invention

[0004] In view of the above-mentioned drawbacks of the prior art, the purpose of the present invention is to provide a precast enlarged head structure for realizing an enlarged bottom after driving a precast hollow pipe pile in order to solve the problem of the prior art that the increase range of the load area at the pile tip by the enlarged head is limited.

Means for Solving the Problems

[0005] To solve the above object and other related objects, the present invention provides a end plate fixedly attached to the lower end surface of a hollow circular pile, with a first through hole drilled through the upper and lower end surfaces; an upper wing hemisphere detachably attached to the lower end surface of the end plate; The present invention provides a precast expanding head structure for achieving base expansion after the installation of a precast hollow pipe pile, comprising a plurality of fan-shaped columnar expanding wings, wherein the expanding wings are provided at the lower end of the end plate in a circular array shape with line segments intersecting along both side walls as axes, the extensions of the line segments intersecting along both side walls coincide with the central axis of the end plate, each of the expanding wings is hinged to the end plate, and the plurality of the expanding wings are located below the upper wing hemisphere, and each of the expanding wings has a rotation axis at the hinge connection portion with the end plate that is perpendicular to the central axis of the end plate in the radial direction.

[0006] As a selectable solution, the planar end of the upper wing hemisphere closes the lower end opening of the first through hole in the end plate, and a plurality of reinforcing bars are arranged in an array in the circumferential direction of the central axis of the upper wing hemisphere, with one end of each reinforcing bar extending into the upper wing hemisphere and the other end extending outside the upper wing hemisphere from the curved end of the upper wing hemisphere, the extension direction of each reinforcing bar is perpendicular to the central axis of the upper wing hemisphere in the radial direction, and each reinforcing bar is welded to the lower end surface of the end plate.

[0007] As a selectable solution, each of the extension wings is fixedly connected to a suspension steel plate, the lower end of the suspension steel plate extends into the extension wing, the upper end surface of the suspension steel plate extends from the upper end surface of the extension wing, and a second through-hole is drilled in both side walls in the width direction of each of the suspension steel plates, and the axis of rotation at the hinge connection portion between the extension wing to which the suspension steel plate is fixedly connected and the end plate coincides with the central axis of the second through-hole of the extension wing. The vertical ends of L-shaped suspension plates are in close contact with both side walls in the width direction of each suspension steel plate, and the two L-shaped suspension plates in close contact with the suspension steel plate in the width direction are installed symmetrically, and the horizontal ends of the L-shaped suspension plates are in close contact with the lower end surface of the end plate, and the horizontal ends of the L-shaped suspension plates are fixedly attached to the end plate, and third through holes are drilled in both side walls of the vertical ends of the L-shaped suspension plates, and the central axis of the third through hole of the L-shaped suspension plate and the central axis of the second through hole of the suspension steel plate to which the L-shaped suspension plate is in close contact coincide, The second through-hole of the suspension steel plate and the third through-holes of the two L-shaped suspension plates that are in close contact with the suspension steel plate in the width direction are connected via a hinge connecting member.

[0008] As a selectable solution, a plurality of screw holes are drilled in a circular array on the lower end surface of the end plate, along the circumferential direction of the central axis of the end plate, and the number of screw holes is the same as the number of extension wings. Each of the aforementioned screw hole groups includes two first screw holes, and a fourth through-hole is drilled in both the upper and lower end surfaces of the horizontal end of the L-shaped suspension plate, with each first screw hole corresponding one-to-one with the fourth through-hole, and when both horizontal ends of the L-shaped suspension plate are in close contact with the lower end surface of the end plate, the central axis of the fourth through-hole of the L-shaped suspension plate and the central axis of the corresponding first screw hole in the end plate coincide. The fourth through-hole of the L-shaped suspension plate and the corresponding first screw hole in the end plate are fixedly connected via a screw connecting member.

[0009] As a selectable solution, each of the extension wings has an arc-shaped groove along the arc length direction of the arc-shaped surface, and both ends of the arc-shaped groove in the arc length direction pass through both ends of the arc length direction of the corresponding arc-shaped surface of the extension wing. When the side walls between multiple extension wings are in close contact with each other, the adjacent ends of two arc-shaped grooves are in communication with each other.

[0010] As a possible solution, when the side walls between the multiple extension wings are in close contact with each other, the curved edge of the upper wing hemisphere abuts against the upper end surface of the extension wing.

[0011] As an optional solution, further include a suspension ring and an impact column for impacting the upper wing hemisphere, If the diameter of the collision column is a and the inner diameter of the hollow circular pile is b, then a <bであり、 A suspension ring is fixedly connected to the upper end surface of the collision column.

[0012] As a selectable solution, if the height of the collision column is e, the straight-line distance between the upper wing hemisphere and the end plate when the upper wing hemisphere fully extends its support wing is f, and the sum of the heights of the hollow circular pile and the end plate is h, then f + h = e.

[0013] As a selectable solution, a limiting plate is provided on the upper end surface of the collision column, the limiting plate is fixedly connected to either the collision column or the suspension ring, and the lower end surface of the limiting plate is at the same height as the upper end surface of the collision column. If the diameter of the limiting plate is c and the outer diameter of the hollow circular pile is d, then b <c≦dである。 [Effects of the Invention]

[0014] As described above, the precast enlarged head structure for achieving base expansion after the installation of precast hollow pipe piles according to the present invention has at least the following beneficial effects.

[0015] 1. In this invention, a deployable expansion wing is provided at the bottom of the hollow circular pile, and the upper wing hemisphere pushes down the expansion wing, thereby achieving base expansion after driving. Compared with conventional mechanical base expansion, this invention simplifies the construction process, allows the base expansion effect to be achieved quickly, and allows the expansion wing to continue expanding outward until it is fully expanded by the subsequent downward impact of the hollow circular pile. This maximizes the load area of ​​the hollow circular pile and significantly improves the tip bearing capacity and pull-out resistance of the hollow circular pile.

[0016] 2. In this invention, when attaching the upper wing hemisphere, the upper wing hemisphere can be welded to the lower end surface of the end plate using reinforcing bars. This allows the planar end of the upper wing hemisphere to close the lower end opening of the hollow circular pile, preventing soil from entering the hollow circular pile during driving, ensuring cleanliness inside the hollow circular pile, and providing space for subsequent work on the impact column. When the upper wing hemisphere expands the expansion wing, the enormous impact force from the collision with the upper wing hemisphere causes the reinforcing bars at the welded area to detach from the end plate. The detached upper wing hemisphere continues to move downwards after the collision and collides with the expansion wing, allowing the hollow circular pile to be rapidly expanded. This is an ingeniously designed structure.

[0017] 3. In this invention, a limiting plate is used to accurately limit the sinking distance when the collision column collides with the upper wing hemisphere so that the upper wing hemisphere exactly expands the support wing completely. At this time, the support wing is not fully deployed. The hollow circular pile sinks by the same sinking distance as the upper wing hemisphere due to the collision by the collision block or other structures. Thereby, during the process of the expanded support wing sinking together with the hollow circular pile, the support wing is fully deployed by the reaction force of the soil, and by increasing the load-bearing area of the support wing and the soil, the tip support force of the hollow circular pile is greatly improved. Also, the end plate can sink until it re-adheres to the upper wing hemisphere, thereby reducing the porosity between the hollow circular pile and the soil after driving.

Brief Description of the Drawings

[0018] [Figure 1] It shows a structural schematic diagram related to the end plate, upper wing hemisphere, and expansion wing of this invention. [Figure 2] It shows an exploded view related to the upper wing hemisphere and end plate of this invention. [Figure 3] It shows an exploded view related to the L-shaped hanging plate and hanging steel plate of this invention. [Figure 4] It shows a structural schematic diagram related to the hanging ring, collision column, and limiting plate of this invention. [Figure 5] It shows a structural schematic diagram related to the end plate and hollow circular pile of this invention. [Figure 6] It shows a structural schematic diagram of the linear distance between the upper wing hemisphere and the end plate when the upper wing hemisphere of this invention completely expands the support wing. [Figure 7] It shows a structural schematic diagram when the support wing of this invention is collided by the upper wing hemisphere and completely expands. [Figure 8] It shows a structural schematic diagram when the completely expanded support wing in this invention sinks until it is completely deployed together with the hollow circular pile.

Modes for Carrying Out the Invention

[0019] Embodiments of the present invention will be illustrated by the following specific examples. Those skilled in the art will readily understand other advantages and effects of the present invention from the disclosures herein.

[0020] Refer to Figures 1 to 8. Note that the structures, proportions, sizes, etc., shown in the drawings herein are solely for the purpose of understanding and viewing by those skilled in the art, and are intended to be combined with the content disclosed in the specification. They do not limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modification of structure, change in proportions, or adjustment of size shall remain within the scope covered by the technical content disclosed herein, as long as it does not affect the effects and objectives that the present invention can achieve. Furthermore, terms such as "up," "down," "left," "right," "center," and "one," used herein, are solely for the purpose of clarifying the explanation and do not limit the scope within which the present invention can be implemented. Changes or adjustments to their relative relationships shall also be considered within the scope within which the present invention can be implemented, as long as they do not substantially alter the technical content.

[0021] The following embodiments are for illustrative purposes only. The embodiments can be combined and are not limited to those shown in any single embodiment below.

[0022] As shown in Figures 1 and 5, the present invention is An end plate 101 is fixedly attached to the lower end surface of a hollow circular pile 102, and has first through holes 103 drilled in its upper and lower end surfaces, An upper wing hemisphere 201 is detachably attached to the lower end surface of the end plate 101, The present invention provides a precast expanding head structure for achieving base expansion after the installation of a precast hollow pipe pile, comprising a plurality of fan-shaped columnar expanding wings 301, wherein the expanding wings are provided at the lower end of the end plate 101 in a circular array shape with line segments intersecting along both side walls as axes, the extensions of the line segments intersecting along both side walls of the expanding wings 301 coincide with the central axis of the end plate 101, each of the expanding wings 301 is hinged to the end plate 101, and the plurality of the expanding wings 301 are located below the upper wing hemisphere 201, and each of the expanding wings 301 has a rotation axis at the hinge connection portion with the end plate 101 that is perpendicular to the central axis of the end plate 101 in the radial direction.

[0023] In this embodiment, during the precasting stage of the hollow circular pile 102, a circular end plate 101 is fixed to the lower end surface of the hollow circular pile 102. When the upper end of the end plate 101 is fixed to the lower end surface of the hollow circular pile 102, the cross-section of the first through hole 103 becomes the same size as the cross-section of the hollow interior of the hollow circular pile 102, and the first through hole 103 communicates with the hollow interior of the hollow circular pile 102. A hemispherical upper wing hemisphere 201 is fixed by welding to the center of the lower surface of the end plate 101. Multiple fan-shaped columnar expansion wings 301 are attached around the center of the lower surface of the end plate 101, hinged and evenly connected in the circumferential direction. In the initial state, all expansion wings 301 are retracted inward, and their outer contours substantially coincide with the outer diameter of the hollow circular pile 102. This completes the attachment of the bottom of the hollow circular pile 102.

[0024] During the driving operation, a hollow circular pile 102, with an upper wing hemisphere 201 and an expansion wing 301 attached to its bottom, is inserted into the excavated hole. The expansion wing 301 at the bottom of the hollow circular pile 102 is expanded by passing through the hollow interior of the hollow circular pile 102 and the first through-hole 103 of the end plate 101 and colliding downward with the upper wing hemisphere 201, thereby achieving a widened base. Next, the hollow circular pile 102 is made to collide downward. Due to the reaction force of the soil, the expanded expansion wing 301 of the hollow circular pile 102 continues to expand outward.

[0025] In this invention, a deployable expansion wing 301 is provided at the bottom of the hollow circular pile 102, and the upper wing hemisphere 201 pushes down the expansion wing 301, thereby achieving base expansion after driving. Compared with conventional mechanical base expansion, this invention simplifies the construction process, allows for quick base expansion, and allows the expansion wing 301 to continue expanding outward until it is fully expanded by subsequently impacting the hollow circular pile 102 downwards. This maximizes the load area of ​​the hollow circular pile 102, significantly improving its tip bearing capacity and pull-out resistance.

[0026] As shown in Figures 1 and 2, the planar end of the upper wing hemisphere 201 closes the lower end opening of the first through hole 103 of the end plate 101, and a plurality of reinforcing bars 202 are arranged in an array in the circumferential direction of the central axis of the upper wing hemisphere 201, with one end of each reinforcing bar 202 extending into the upper wing hemisphere 201 and the other end extending out of the upper wing hemisphere 201 from the curved end of the upper wing hemisphere 201, and the extension direction of each reinforcing bar 202 is perpendicular to the central axis of the upper wing hemisphere 201 in the radial direction, and each reinforcing bar 202 is welded to the lower end surface of the end plate 101.

[0027] Here, the method for welding the reinforcing bars to the lower end surface of the end plate 101 is spot welding. The role of spot welding is to temporarily fix the upper wing hemisphere 201 to the end plate 101 before it is struck. Furthermore, spot welding allows the upper wing hemisphere 201 to be separated from the end plate 101 with only a small impact force during the concrete casting process. This saves construction time.

[0028] In this embodiment, when fixing the upper wing hemisphere 201 to the lower end surface of the end plate 101, the upper wing hemisphere 201 is fixedly connected to the lower end surface of the end plate 101 by welding a plurality of reinforcing bars 202 extending from the curved end of the upper wing hemisphere 201 to the end plate 101, and the planar end of the upper wing hemisphere 201 closes the lower end opening of the hollow circular pile 102.

[0029] During the driving operation, the upper wing hemisphere 201 collides downwards, expanding the expansion wing 301 at the bottom of the hollow circular pile 102. Due to the enormous impact force from the upper wing hemisphere 201, the reinforcing bars 202 at the welded joint detach from the end plate 101. The upper wing hemisphere 201 continues to move downwards under the impact, thereby expanding the expansion wing 301 at the bottom of the hollow circular pile 102.

[0030] In this invention, when attaching the upper wing hemisphere 201, the upper wing hemisphere 201 can be welded to the lower end surface of the end plate 101 using reinforcing bars 202. This allows the planar end of the upper wing hemisphere 201 to close the lower end opening of the hollow circular pile 102, preventing soil from entering the hollow circular pile 102 during driving, ensuring cleanliness inside the hollow circular pile 102, and providing space for subsequent work on the impact column 502. When the upper wing hemisphere 201 expands the expansion wing 301, the enormous impact force from the collision with the upper wing hemisphere 201 causes the reinforcing bars 202 at the welded area to detach from the end plate 101. The detached upper wing hemisphere 201 continues to move downward under impact, allowing the hollow circular pile 102 to be rapidly expanded. This is an ingeniously designed structure.

[0031] As shown in Figures 1 and 3, each of the extension wings 301 has a suspension steel plate 302 fixedly connected to it, the lower end of the suspension steel plate 302 extends into the extension wing 301, the upper end surface of the suspension steel plate 302 extends from the upper end surface of the extension wing 301, and each of the two side walls in the width direction of the suspension steel plate 302 has a second through hole 303 drilled in it, and the axis of rotation at the hinge connection portion between the extension wing 301 to which the suspension steel plate 302 is fixedly connected and the end plate 101 coincides with the central axis of the second through hole 303 of the extension wing 301. Each of the two L-shaped suspension plates 304 has a vertical end in close contact with both side walls in the width direction of the suspension steel plate 302, and the two L-shaped suspension plates 304 that are in close contact with the suspension steel plate 302 in the width direction are installed symmetrically, and the horizontal ends of each L-shaped suspension plate 304 are in close contact with the lower end surface of the end plate 101, and the horizontal ends of each L-shaped suspension plate 304 are fixedly attached to the end plate 101, and a third through hole 305 is drilled in both side walls of the vertical end of each L-shaped suspension plate 304, and the central axis of the third through hole 305 of the L-shaped suspension plate 304 coincides with the central axis of the second through hole 303 of the suspension steel plate 302 to which the L-shaped suspension plate 304 is in close contact. The second through-hole 303 of the suspension steel plate 302 and the third through-hole 305 of the two L-shaped suspension plates 304 that are in close contact with the suspension steel plate 302 in the width direction are connected via a hinge connecting member.

[0032] Here, the hinge connecting member is not limited to, but functions to rotatably connect the suspension steel plate 302 to the L-shaped suspension plate 304. The screw connecting member used in this embodiment is an eye bolt.

[0033] In this embodiment, after the upper wing hemisphere 201 has been fixedly attached, several L-shaped suspension plates 304 are first fixed and attached to the end plate 101. Since the L-shaped suspension plates 304 are grouped in pairs, the third through holes 305 of the L-shaped suspension plates 304 in each group are arranged coaxially. The extension wing 301 is inserted between the vertical ends of the L-shaped suspension plates 304 in each group. When inserting the extension wing 301, the extensions of the line segments that intersect along the side walls of the extension wing 301 coincide with the central axis of the end plate 101. Specifically, the suspension steel plate 302 fixedly connected to the extension wing 301 is inserted until each of the side walls is in close contact with the side wall opposite the vertical end of one group of L-shaped suspension plates 304, and the second through hole 303 of the suspension steel plate 302 is coaxially positioned with the third through hole 305 of the L-shaped suspension plate 304 of that group, and the eyebolt is passed sequentially through the third through hole 305 of the L-shaped suspension plate 304 on one side, the second through hole 303 of the suspension steel plate 302, and the third through hole 305 of the L-shaped suspension plate 304 on the other side, and the above steps are repeated for the remaining groups of L-shaped suspension plates 304, thereby hinge-connecting the multiple extension wings 301 to the end plate 101.

[0034] In this invention, a detachable suspension steel plate 302 and an L-shaped suspension plate 304 are fitted together with a hinge to form a robust and easy-to-assemble hinged connection structure. This design makes it easy to manufacture, transport, and replace individual extension wings 301 individually, and the hinge connection point is located on the top of the extension wing 301, and the lever arm is long, which is advantageous for effectively pushing and deploying the extension wing 301 with a small stroke when the upper wing hemisphere 201 moves downward.

[0035] As shown in Figures 1 and 3, a plurality of screw holes are drilled in a circular array on the lower end surface of the end plate 101 along the circumferential direction of the central axis of the end plate 101, and the number of screw holes is the same as the number of extension wings 301. Each of the screw hole groups includes two first screw holes 104, and a fourth through hole 306 is drilled in both the upper and lower end surfaces of the horizontal end of the L-shaped suspension plate 304, with each first screw hole 104 corresponding one-to-one with the fourth through hole 306, and when both horizontal ends of the L-shaped suspension plate 304 are in close contact with the lower end surface of the end plate 101, the central axis of the fourth through hole 306 of the L-shaped suspension plate 304 and the central axis of the corresponding first screw hole 104 in the end plate 101 coincide. The fourth through hole 306 of the L-shaped suspension plate 304 and the corresponding first screw hole 104 in the end plate 101 are fixedly connected via a screw connecting member.

[0036] Here, the screw connection member is not limited to any particular type, but functions to securely connect the L-shaped suspension plate 304 to the end plate 101. The screw connection member used in this embodiment is a screw.

[0037] In this embodiment, when fixing and attaching multiple L-shaped suspension plates 304 to the end plate 101, the multiple L-shaped suspension plates 304 are grouped in pairs, and the upper end surfaces of the horizontal ends of two L-shaped suspension plates 304 in each group are in close contact with the lower end surface of the end plate 101. The fourth through holes 306 of the two L-shaped suspension plates 304 are aligned with two adjacent first screw holes 104 in the end plate 101. The outer end surfaces of the vertical ends of the two L-shaped suspension plates 304 are rotated until they are close together and parallel to each other. Then, two screws are inserted into the corresponding fourth through holes 306 of the L-shaped suspension plates 304 and screwed into the first screw holes 104 in the end plate 101, thereby fixing and attaching the L-shaped suspension plates 304 to the end plate 101.

[0038] In this invention, the L-shaped suspension plate 304 and the end plate 101 are detachably connected by connecting and fixing the L-shaped suspension plate 304 with screws. This makes it possible to modularize and precast the L-shaped suspension plate 304 in the factory, greatly simplifying transportation and storage.

[0039] As shown in Figure 1, each of the extension wings 301 has an arc-shaped groove 401 along the arc length direction of the arc-shaped surface, and both ends of the arc-shaped groove 401 in the arc length direction pass through both ends of the arc-shaped surface of the corresponding extension wing 301 in the arc length direction. When the side walls between the multiple extension wings 301 are in close contact with each other, the adjacent ends of two arc-shaped grooves 401 are in communication with each other.

[0040] In this embodiment, after hinge-connecting multiple expansion wings 301 to L-shaped suspension plates 304, the multiple expansion wings 301 are fitted together to form a large cylinder. The arc-shaped grooves 401 of adjacent expansion wings 301 are joined and communicate at the contact points of their side walls. Along the arc length direction of the arc surfaces of the multiple expansion wings 301, the multiple communicating arc-shaped grooves 401 are surrounded by cable ties, and the multiple expansion wings 301 are bound together as a single unit with the cable ties. The cable ties that bind the multiple expansion wings 301 are located inside the multiple arc-shaped grooves 401. In this way, the expansion wings 301 are temporarily fitted together as a single unit, and the side walls of the multiple expansion wings 301 are maintained in close contact with each other.

[0041] In this invention, multiple expansion wings 301, which are hinged to an L-shaped suspension plate 304, are bound together with cable ties. This prevents the expansion wings 301 from opening before casting, ensuring they enter the excavated hole together with the hollow circular pile 102. Furthermore, the position of the cable ties is restricted by the arc-shaped groove 401, preventing the cable ties from easily coming off the expansion wings 301 before casting. This is a cleverly designed structure.

[0042] As shown in Figure 1, when the side walls between the multiple extension wings 301 are in close contact with each other, the curved end of the upper wing hemisphere 201 abuts against the upper end surface of the extension wing 301.

[0043] In this embodiment, after the upper wing hemisphere 201 has been fixedly attached, the multiple extension wings 301 are all hinged to the L-shaped suspension plate 304 and completely retracted inward, so that their leading edges are in close contact with the lower spherical surface of the upper wing hemisphere 201.

[0044] In this invention, when cast, the upper wing hemisphere 201 is impacted and detaches from the end plate 101, and can directly collide with the leading edge region of the expansion wing 301 without displacement. As a result, the torque during rotation of the expansion wing 301 is maximized, which allows the upper wing hemisphere 201 to expand the expansion wing 301 more easily.

[0045] As shown in Figures 2, 4, and 5, the system further includes a suspension ring 501 and an impact column 502 for impacting the upper wing hemisphere 201. If the diameter of the collision column 502 is a and the inner diameter of the hollow circular pile 102 is b, then a <bであり、 The diameter of the collision column 502 used in this embodiment is 80% of the inner diameter of the hollow circular pile 102, i.e., a = 0.8b. A suspension ring 501 is fixedly connected to the upper end surface of the collision column 502.

[0046] In this embodiment, the upper wing hemisphere 201 is welded to the end plate 101 with reinforcing bars 202, then multiple L-shaped suspension plates 304 are fixed and attached to the end plate 101, and then multiple expansion wings 301 are hinged to the L-shaped suspension plates 304 and completely retracted inward. After that, the multiple expansion wings 301 are temporarily fixed in the retracted state with cable ties, and then driven into the ground together with the hollow circular pile 102. If it is necessary to expand the expansion wings 301 after driving into the ground, a rope is attached to the suspension ring 501, then the impact column 502 is inserted from the top of the inner hole of the hollow circular pile 102, the rope is repeatedly pulled up and lowered, and the impact column 502 is lowered by its own weight and impacts the upper wing hemisphere 201 below. When the upper wing hemisphere 201 detaches from the end plate 101, it directly impacts the expansion wings 301, causing the expansion wings 301 to expand outward. As the extended wing 301 extends outward, the cable ties break. Subsequently, the rope is repeatedly raised and lowered, and the impact column 502 continues to collide with the upper wing hemisphere 201 below due to its own weight. When the upper wing hemisphere 201 reaches a predetermined position, the collision stops.

[0047] This invention provides a simple, highly efficient, and low-cost trigger mechanism for the expanding wing 301, which does not require complex hydraulic or electrical equipment. The base expansion operation can be achieved solely by the impact force converted from the gravitational potential energy of the impact column 502. The impact column 502 can operate directly within the internal bore of the hollow circular pile 102, making it suitable for narrow construction sites, and the construction method is flexible and rapid.

[0048] As shown in Figures 4 to 6, if e is the height of the collision column 502, f is the straight-line distance between the upper wing hemisphere 201 and the end plate 101 when the upper wing hemisphere 201 fully extends its support wing, and h is the sum of the heights of the hollow circular pile 102 and the end plate 101, then f + h = e.

[0049] In this embodiment, the upper wing hemisphere 201 is welded to the end plate 101 with reinforcing bars 202, then multiple L-shaped suspension plates 304 are fixed and attached to the end plate 101, and then multiple expansion wings 301 are hinged to the L-shaped suspension plates 304 and completely retracted inward. After that, the multiple expansion wings 301 are temporarily fixed in the retracted state with cable ties, and then driven into the ground together with the hollow circular pile 102. If it is necessary to expand the expansion wings 301 after driving into the ground, a rope is attached to the suspension ring 501, then the impact column 502 is inserted from the top of the inner hole of the hollow circular pile 102, the rope is repeatedly pulled up and lowered, and the impact column 502 is lowered by its own weight and impacts the upper wing hemisphere 201 below. When the upper wing hemisphere 201 detaches from the end plate 101, it directly impacts the expansion wings 301, causing the expansion wings 301 to expand outward. As the extension wing 301 expands outward, the cable tie breaks. The rope is then repeatedly pulled up and lowered, causing the impact column 502 to repeatedly collide with the upper wing hemisphere 201 below under its own weight. When the impact column 502 collides with the upper wing hemisphere 201 and its upper end surface becomes flush with the upper end surface of the hollow circular pile 102, the upper wing hemisphere 201 has fully extended its support wing and is awaiting the next operation.

[0050] In this invention, as the collision column 502 descends until its top is flush with the pile head, its bottom is ensured to push the upper wing hemisphere 201 to a predetermined position that fully deploys the expansion wing 301. This provides a clear visual indicator of completion of construction. When the top of the collision column 502 is flush with the pile head, the operator can intuitively determine that the base expansion operation is complete, eliminating the need for additional measurements or estimations and ensuring reliable control of construction quality.

[0051] As shown in Figures 4 to 8, a limiting plate 503 is provided on the upper end surface of the collision column 502, and the limiting plate 503 is fixedly connected to both the collision column 502 and the suspension ring 501, and the lower end surface of the limiting plate 503 is at the same height as the upper end surface of the collision column 502. If the diameter of the limiting plate 503 is c and the outer diameter of the hollow circular pile 102 is d, then b <c≦dであり、 The diameter of the limiting plate 503 used in this embodiment is the same as the outer diameter of the hollow circular pile 102, that is, c = d.

[0052] In this embodiment, the upper wing hemisphere 201 is welded to the end plate 101 with reinforcing bars 202, then multiple L-shaped suspension plates 304 are fixed and attached to the end plate 101, and then multiple expansion wings 301 are hinged to the L-shaped suspension plates 304 and completely retracted inward. After that, the multiple expansion wings 301 are temporarily fixed in the retracted state with cable ties, and then driven into the ground together with the hollow circular pile 102. If it is necessary to expand the expansion wings 301 after driving into the ground, a rope is attached to the suspension ring 501, then the impact column 502 is inserted from the top of the inner hole of the hollow circular pile 102, the rope is repeatedly pulled up and lowered, and the impact column 502 is lowered by its own weight and impacts the upper wing hemisphere 201 below. When the upper wing hemisphere 201 detaches from the end plate 101, it directly impacts the expansion wings 301, causing the expansion wings 301 to expand outward. As the expanding wing 301 expands outward, the cable ties break. The rope is then repeatedly pulled up and lowered, and the impact column 502 continues to collide with the upper wing hemisphere 201 below under its own weight. The impact column 502 continues to collide until the lower end surface of the limiting plate 503 is in close contact with the upper end surface of the hollow circular pile 102, that is, until the sinking distance of the upper wing hemisphere 201 is f. At this point, the upper wing hemisphere 201 has fully expanded its support wings, but the support wings have not fully unfolded. The impact column 502 is then removed, and a uniform impact force is applied downward from the upper end surface of the hollow circular pile 102 using impact blocks or other structures. When the hollow circular pile 102 sinks by a distance f under the action of the impact block or other structures, the expanded support wing fully unfolds due to the reaction force of the soil during the process of sinking together with the hollow circular pile 102, and when the end plate 101 is re-attached to the upper wing hemisphere 201, the sinking of the hollow circular pile 102 stops, thus completing the driving of the hollow circular pile 102.

[0053] In this invention, the limiting plate 503 is used to precisely limit the settlement distance when the collision column 502 collides with the upper wing hemisphere 201, so that the upper wing hemisphere 201 fully extends its support wings, although the support wings are not fully extended at this time. The hollow circular pile 102 settles by the same settlement distance as the upper wing hemisphere 201 due to collisions with the collision block or other structures. As a result, the extended support wings fully extend due to the reaction force of the soil during the settlement process together with the hollow circular pile 102, increasing the load area between the support wings and the soil, thereby significantly improving the tip bearing capacity of the hollow circular pile 102. Furthermore, the end plate 101 can settle until it is in close contact with the upper wing hemisphere 201, thereby reducing the void ratio between the hollow circular pile 102 and the soil after installation.

[0054] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the scope of the present invention. Any person skilled in the art can modify or change the above embodiments without contradicting the spirit and scope of the present invention. Accordingly, all equivalent modifications or changes made by a person skilled in the art without departing from the spirit and technical idea disclosed herein shall still be included within the claims of the present invention. [Explanation of Symbols]

[0055] 101 End plate 102 Hollow circular stake 103 First through hole 104 First screw hole 201 Upper wing hemisphere 202 Reinforcement bars 301 Extendable Wing 302 Suspension Steel Plate 303 Second through hole 304 L-shaped hanging plate 305 Third through hole 306 Fourth through hole 401 Arc-shaped groove 501 Hanging Ring 502 Collision Pillar 503 Restriction board

Claims

1. A precast enlarged head structure for achieving base expansion after the installation of precast hollow pipe piles, An end plate is fixedly attached to the lower end surface of a hollow circular pile, and has first through holes drilled in its upper and lower end surfaces, An upper wing hemisphere that is detachably attached to the lower end surface of the end plate, A precast expanding head structure for achieving base expansion after driving a precast hollow pipe pile, characterized by comprising a plurality of fan-shaped columnar expanding wings, wherein the expanding wings are provided at the lower end of the end plate in a circular array with line segments intersecting along both side walls as axes, the extensions of the line segments intersecting along both side walls coincide with the central axis of the end plate, each of the expanding wings is provided hinged to the end plate, and the plurality of the expanding wings are located below the upper wing hemisphere, and each of the expanding wings has a rotation axis at the hinge connection portion with the end plate that is perpendicular to the central axis of the end plate in the radial direction.

2. The planar end of the upper wing hemisphere closes the lower end opening of the first through hole of the end plate, a plurality of reinforcing bars are arranged in an array in the circumferential direction of the central axis of the upper wing hemisphere, one end of each reinforcing bar extends into the upper wing hemisphere and the other end extends out of the upper wing hemisphere from the curved end of the upper wing hemisphere, the extension direction of each reinforcing bar is perpendicular to the central axis of the upper wing hemisphere in the radial direction, and each reinforcing bar is welded to the lower end surface of the end plate, characterized in that the precast expanding head structure for achieving base expansion after driving a precast hollow pipe pile according to claim 1.

3. Each of the aforementioned extension wings is fixedly connected to a suspension steel plate, the lower end of the suspension steel plate extends into the extension wing, the upper end surface of the suspension steel plate extends from the upper end surface of the extension wing, and a second through-hole is drilled in both side walls in the width direction of each of the aforementioned suspension steel plates, and the axis of rotation at the hinge connection portion between the extension wing to which the suspension steel plate is fixedly connected and the end plate coincides with the central axis of the second through-hole of the extension wing. The vertical ends of L-shaped suspension plates are in close contact with both side walls in the width direction of each suspension steel plate, and the two L-shaped suspension plates in close contact with the suspension steel plate in the width direction are installed symmetrically, and the horizontal ends of the L-shaped suspension plates are in close contact with the lower end surface of the end plate, and the horizontal ends of the L-shaped suspension plates are fixedly attached to the end plate, and third through holes are drilled in both side walls of the vertical ends of the L-shaped suspension plates, and the central axis of the third through hole of the L-shaped suspension plate and the central axis of the second through hole of the suspension steel plate to which the L-shaped suspension plate is in close contact coincide, The precast expanding head structure for achieving base expansion after driving a precast hollow pipe pile, as described in claim 1, is characterized in that the second through-hole of the suspension steel plate and the third through-holes of the two L-shaped suspension plates that are in close contact with the suspension steel plate in the width direction are connected via a hinge connecting member.

4. Multiple screw holes are arranged in a circular array on the lower end surface of the end plate, along the circumferential direction of the central axis of the end plate, and the number of screw holes is the same as the number of extension wings. Each of the aforementioned screw hole groups includes two first screw holes, and a fourth through-hole is drilled in both the upper and lower end surfaces of the horizontal end of the L-shaped suspension plate, with each first screw hole corresponding one-to-one with the fourth through-hole, and when both horizontal ends of the L-shaped suspension plate are in close contact with the lower end surface of the end plate, the central axis of the fourth through-hole of the L-shaped suspension plate and the central axis of the corresponding first screw hole in the end plate coincide. The precast enlarged head structure for achieving base enlargement after driving a precast hollow pipe pile, as described in claim 3, characterized in that the fourth through hole of the L-shaped suspension plate and the corresponding first screw hole in the end plate are fixedly connected via a screw connecting member.

5. Each of the aforementioned extension wings has an arc-shaped groove along the arc length direction of its arc-shaped surface, and both ends of the arc-shaped groove in the arc length direction pass through both ends of the arc length direction of the corresponding arc-shaped surface of the extension wing. The precast expanding head structure for achieving base expansion after driving a precast hollow pipe pile, as described in claim 1, characterized in that when the side walls between a plurality of the expanding wings are in close contact with each other, the approaching ends of two adjacent arc-shaped grooves are in communication with each other.

6. The precast expanding head structure for achieving base expansion after driving a precast hollow pipe pile, characterized in that when the side walls between a plurality of the expanding wings are in close contact with each other, the curved end of the upper wing hemisphere abuts against the upper end surface of the expanding wing, as described in claim 2.

7. It further includes a suspension ring and an impact column for impacting the upper wing hemisphere, If the diameter of the collision column is a and the inner diameter of the hollow circular pile is b, then a < b. The precast enlarged head structure for achieving base enlargement after driving a precast hollow pipe pile, as described in claim 1, characterized in that a suspension ring is fixedly connected to the upper end surface of the collision column.

8. The precast expanding head structure for achieving base expansion after driving a precast hollow pipe pile, as described in claim 7, wherein the height of the collision column is e, the straight-line distance between the upper wing hemisphere and the end plate when the upper wing hemisphere fully extends its support wing is f, and the sum of the heights of the hollow circular pile and the end plate is h, such that f + h = e.

9. A limiting plate is provided on the upper end surface of the collision column, and the limiting plate is fixedly connected to both the collision column and the suspension ring, and the lower end surface of the limiting plate is at the same height as the upper end surface of the collision column. The precast enlarged head structure for achieving base enlargement after driving a precast hollow pipe pile, characterized in that, if the diameter of the limiting plate is c and the outer diameter of the hollow circular pile is d, then b < c ≤ d.

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