A kind of expanding bottom self-expanding pile and construction method

Abstract

The application discloses an expanded-bottom self-expanding pile and a construction method, and belongs to the technical field of pile foundation engineering. The expanded-bottom self-expanding pile comprises a bottom pile, a sealing sleeve, a plurality of expansion bodies, a plurality of sliding push plates and a force applying assembly. A plurality of slot grooves communicating with the outside are formed in the bottom of the bottom pile, the sealing sleeve is sleeved on the outer periphery of the bottom of the bottom pile, the expansion bodies are circumferentially arranged on the inner side wall of the bottom pile and are internally loaded with expansion materials, the sliding push plates are arranged in correspondence with the expansion bodies, the force applying assembly is located in the middle of the enclosed circle of the sliding push plates and can apply circumferential outside thrust, the sliding push plates are pushed to extrude the expansion bodies, and the expansion materials enter the sealing sleeve through the slot grooves. During construction, the pile is first sunk, then the force applying assembly is controlled to push the materials, and then water and grout are injected into the sealing sleeve, so that a plurality of circumferentially distributed enlarged heads are formed on the outer periphery of the bottom of the bottom pile. The application combines mechanical material pushing, water injection expansion and grouting solidification, solves the problems of uncontrollable expanded-head form and poor reliability of the expanded-bottom pile, and effectively improves the pile foundation bearing capacity and the anti-pulling performance.

Description

Technical Field

[0001] This invention relates to the field of pile foundation engineering technology, and in particular to an enlarged-base self-expanding pile and its construction method. Background Technology

[0002] Currently, pile foundations are widely used in various engineering projects. To improve the vertical bearing capacity and pull-out resistance of pile foundations, enlarged-base piles are usually used, which means forming an enlarged head at the pile end to increase the bearing area at the pile end.

[0003] Existing enlarged-base piles typically form an enlarged head by mechanically enlarging the borehole and then grouting or injecting concrete. However, mechanical enlargement involves complex construction procedures and low efficiency; while post-grouting methods result in limited diffusion of the grout within the strata and are difficult to control precisely, leading to irregular shapes and uncontrollable sizes of the enlarged heads, which in turn affects the stability and reliability of the pile foundation's bearing capacity.

[0004] Therefore, how to form a controllable, stable, and reliable enlarged head is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide an enlarged-base self-expanding pile and its construction method, aiming to solve the problem of how to form an enlarged head with controllable shape and stable reliability in the enlarged-base pile.

[0006] To solve the above-mentioned technical problems, the objective of this invention is achieved through the following technical solution: providing an enlarged-base self-expanding pile, comprising: The bottom pile has multiple grooves that connect to the outside along the circumferential direction on the inner side wall of the bottom. A sealing sleeve is fitted onto the outer periphery of the bottom of the bottom pile and communicates with the inner bottom of the bottom pile through the groove. Multiple expansion bodies are arranged circumferentially on the inner sidewall of the bottom of the bottom pile, and correspond to the multiple grooves; Multiple sliding push plates are set at the bottom of the bottom pile and can abut against multiple expansion bodies in the circumferential outward direction. Each sliding push plate corresponds to one of the multiple expansion bodies. The force-applying component is located at the bottom of the bottom pile and in the middle of the enclosing ring formed by multiple sliding push plates, and can apply thrust in the circumferential outward direction; The force-applying component is used to push the plurality of sliding push plates to squeeze the plurality of expansion bodies respectively when it applies a thrust outward along the circumference, so as to drive the expansion material in the expansion body into the sealing sleeve through the groove.

[0007] Furthermore, the expanded-base self-expanding pile also includes a water injection component, which is disposed inside the bottom pile and connected to the bottom outer periphery of the bottom pile. The water injection component is used to transport external water to the sealing sleeve on the bottom outer periphery of the bottom pile.

[0008] Furthermore, the expanded-base self-expanding pile also includes a grouting assembly, which is disposed inside the bottom pile and connected to the bottom outer periphery of the bottom pile. The grouting assembly is used to transport external grouting material to the sealing sleeve on the bottom outer periphery of the bottom pile.

[0009] Further, the expanded body includes: An expansion chamber, filled with expanding material; The movable plate is vertically arranged and located on the side of the expansion cavity away from the inner wall of the bottom pile; the multiple sliding push plates and the movable plates of the multiple expansion bodies correspond one-to-one, and the sliding push plates are located at the lower part of the movable plate; The lower part of the expansion cavity is provided with a discharge nozzle that corresponds to the slot. The sliding push plate is used to drive the movable plate to tilt and squeeze the expansion body when it presses the lower part of the movable plate in the circumferential outward direction, so that the vertical cross section of the expansion body is inverted cone shape.

[0010] Furthermore, the expanded-base self-expanding pile also includes a limiting plate installed on the inner side wall of the bottom pile, the limiting plate being located above the expansion cavity and the movable plate; the limiting plate is used to cooperate with the top of the movable plate to prevent the top of the expansion cavity from being squeezed out when the movable plate tilts.

[0011] Furthermore, the limiting plate is arc-shaped, and when the movable plate is tilted, its top slides along the arc-shaped surface of the limiting plate.

[0012] Furthermore, the force-applying component includes: A linkage is provided at the inner bottom of the bottom pile and connected to multiple sliding push plates; The drive unit is vertically oriented and can move up and down. The drive unit is used to push the linkage to move when it moves downward, and to drive the multiple sliding push plates to slide in the circumferential outward direction and squeeze the multiple expansion bodies respectively.

[0013] Furthermore, the linkage includes: The upright is fixedly installed at the inner bottom of the bottom pile; The slider is slidably mounted on the upright in a vertical direction; Multiple connecting rods correspond one-to-one with the multiple sliding push plates. One end of each connecting rod is rotatably connected to the slider, and the other end of each connecting rod is rotatably connected to the corresponding sliding push plate.

[0014] Furthermore, the driving unit is connected to the slider and is used to drive the slider to move vertically on the upright.

[0015] This invention also provides a construction method for an enlarged-base self-expanding pile, applied to the enlarged-base self-expanding pile described above, the construction method comprising: The bottom piles were hoisted into place and sunk into the seabed to the design elevation; The force-applying component is controlled to provide a circumferential outward thrust, which pushes the plurality of sliding push plates to squeeze the plurality of expansion bodies respectively, so that the expansion material in the expansion body enters the sealing sleeve through the groove; Water is injected into the sealing sleeve, causing the expansion material inside the sealing sleeve to expand upon contact with water, thereby driving the sealing sleeve to expand outward and compress the surrounding soil. Grouting material is injected into the sealing sleeve through the grouting assembly. After the grouting material solidifies, it forms multiple circumferentially distributed enlarged heads on the outer periphery of the bottom of the pile together with the expanded material.

[0016] The beneficial effects of this invention are as follows: Initial filling and positioning of the expansive material is achieved through mechanical thrust; the expansion force generated by water expansion actively compacts and secondary enlarges the surrounding soil; and high-strength composite enlarged heads are formed through grouting material curing. Ultimately, multiple circumferentially distributed, controllable, and structurally dense enlarged heads are formed at the bottom of the pile. This avoids the limitations of single mechanical hole enlargement or single grouting processes. The various stages complement and synergistically enhance the vertical bearing capacity and pull-out resistance of offshore photovoltaic pile foundations. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural schematic diagram of a self-expanding pile with an enlarged base (before the extrusion body) provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a self-expanding pile with an enlarged base (after extrusion of the expansion body) provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the principle structure of the force-applying component (before force application) provided in an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the principle structure of the force-applying component (after force is applied) provided in an embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of the principle structure of the sliding push plate (before sliding) provided in an embodiment of the present invention.

[0021] Figure 6 This is a schematic diagram of the principle structure of the sliding push plate (after sliding) provided in an embodiment of the present invention.

[0022] Figure 7 This is a structural schematic diagram of an expanded-base self-expanding pile (after construction) provided in an embodiment of the present invention.

[0023] Figure 8 This is a schematic diagram of the construction method for an expanded-base self-expanding pile provided in an embodiment of the present invention.

[0024] Explanation of the markings in the image: 1. Bottom pile; 11. Pile base; 2. Sealing sleeve; 3. Expansion body; 31. Expansion cavity; 32. Movable plate; 4. Sliding push plate; 5. Force application assembly; 51. Linkage component; 511. Upright pole; 512. Slider; 513. Connecting rod; 52. Drive unit; 6. Water injection assembly; 7. Grouting assembly; 8. Limiting plate; 9. Enlarged head. Detailed Implementation

[0025] 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 some, not all, of the embodiments of the present invention. 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.

[0026] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0027] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0029] Please see Figure 1 and Figure 2 The present invention provides an expanded-base self-expanding pile, including a bottom pile 1, a sealing sleeve 2, multiple expansion bodies 3, multiple sliding push plates 4 and a force application component 5; The bottom pile 1, as the main body of the pile, can be made of steel pipe structure. The pile base 11 at its bottom is cone-shaped to facilitate penetration into the target soil layer. Multiple slots connecting to the outside are opened along the circumferential direction on the inner side wall of the bottom of the bottom pile 1. These slots penetrate the wall thickness of the bottom pile 1 radially, thereby connecting the internal space of the bottom pile 1 with the outside. The sealing sleeve 2 is fitted around the bottom of the bottom of the bottom pile 1 and communicates with the inner bottom of the bottom pile 1 through these grooves, so that the material (i.e., the expansion material) squeezed out from the inside through the grooves can directly enter the inner cavity of the sealing sleeve 2. Multiple expansion bodies 3 are arranged circumferentially on the inner side wall of the bottom of the bottom pile 1. The position of each expansion body 3 corresponds to a groove (or a group of grooves). Multiple expansion bodies 3 are distributed circumferentially at intervals, which can correspond to different positions on the outer periphery of the bottom of the bottom pile 1. The expansion bodies 3 are pre-filled with water-swellable expansion material. Multiple sliding push plates 4 are disposed at the bottom of the bottom pile 1. Each sliding push plate 4 corresponds to an expansion body 3. The sliding push plate 4 is located inside the expansion body 3 and can abut against the multiple expansion bodies 3 in the circumferential outward direction (i.e., the radial direction of the bottom pile 1). The force-applying component 5 is located at the bottom of the bottom pile 1. The force-applying component 5 is positioned in the center area of ​​the enclosure formed by all the sliding push plates 4. The force-applying component 5 can simultaneously apply thrust in the circumferential outward direction (i.e., away from the center).

[0030] As described above, during operation, the force-applying component 5 applies a thrust in the circumferential outward direction. This thrust is transmitted to each sliding push plate 4, causing multiple sliding push plates 4 to slide outward synchronously. During the movement, the sliding push plates 4 squeeze their respective corresponding expansion bodies 3. After being compressed, the expansion material inside the expansion body 3 is forced out of the expansion body 3 and squeezed out of the wall of the bottom pile 1 through the corresponding slot, and finally enters the sealing sleeve 2 that is already fitted outside the bottom pile 1. This causes the sealing sleeve 2 to be expanded on the outer periphery of the bottom of the bottom pile 1, forming an expanded bottom area of ​​a predetermined size.

[0031] Based on this, this embodiment uses the force-applying component 5 to push the sliding push plate 4 to compress the expansion body 3, thereby actively feeding the expansion material into the sealing sleeve 2 by mechanical pushing. This avoids the defects of uncontrollable morphology caused by grouting methods that rely solely on the uncertain diffusion of the formation, and initially forms a locally enlarged structure with controllable morphology and accurate position, laying the foundation for the subsequent formation of a reliable enlarged head 9 (see reference). Figure 7 This provides a definite structural basis.

[0032] Furthermore, the expansion material loaded inside the expansion body 3 can be a water-swellable material, such as water-swellable rubber, water-swellable polyurethane, or bentonite-based composite material. After the expansion material is squeezed into the sealing sleeve 2 through the slot, simply adding water to the sealing sleeve 2 will cause the water-swellable material to come into contact with the water and expand in volume. Under the constraint of the sealing sleeve 2, it expands radially outward, thereby further expanding the sealing sleeve 2 and compressing the surrounding soil without the need for continuous mechanical force, forming a local enlargement structure. At the same time, since multiple expansion bodies 3 are distributed circumferentially along the bottom of the bottom pile 1, each expansion body 3 corresponds to a slot and an orientation. The squeezed expansion material will expand in different circumferential orientations within the sealing sleeve 2 after water is added, thereby forming multiple circumferentially spaced local enlargement structures on the outer periphery of the bottom of the bottom pile 1. This makes the size and shape of each enlargement structure controllable and the position stable, forming an overall circumferentially distributed enlarged bottom structure with controllable shape and stable reliability.

[0033] In one embodiment, the expanded-base self-expanding pile further includes a water injection component 6, which is disposed inside the bottom pile 1 and connected to the bottom outer periphery of the bottom pile 1. The water injection component 6 is used to transport external water to the sealing sleeve 2 at the bottom outer periphery of the bottom pile 1.

[0034] Specifically, the water injection component 6 includes at least one water injection pipe, which is longitudinally arranged and fixed along the inner sidewall of the bottom pile 1. Its upper end extends to the top of the bottom pile 1 or outside the pile top for easy connection with external water supply equipment, and its lower end extends to the bottom of the bottom pile 1 and is located within the axial height range covered by the sealing sleeve 2. The lower end outlet of the water injection pipe is connected to the inner cavity of the sealing sleeve 2. The connection path can be achieved by opening a special water injection hole on the sidewall of the bottom pile 1. The lower end of the water injection pipe is inserted into the water injection hole and sealed to allow direct communication between the pipe cavity and the inside of the sealing sleeve 2. The number of water injection pipes can be set to one or more according to the requirements of water injection uniformity. The layout path avoids the expansion body 3, the sliding push plate 4, and the force application component 5, so as not to interfere with their movement trajectory.

[0035] Based on this, the water injection component 6 integrated inside the bottom pile 1 enables active and controllable water supply to the sealing sleeve 2, ensuring that the water-swellable material can expand in a timely and sufficient manner after extrusion. The water injection path is fixed inside the bottom pile 1, does not occupy the space outside the pile, does not interfere with the pile driving construction, and the pipeline is protected by the structure of the bottom pile 1, thus having high operational reliability in the seabed environment.

[0036] In one embodiment, the expanded-base self-expanding pile further includes a grouting assembly 7, which is disposed inside the bottom pile 1 and communicates with the bottom outer periphery of the bottom pile 1. The grouting assembly 7 is used to transport external grouting material to the sealing sleeve 2 at the bottom outer periphery of the bottom pile 1.

[0037] In this embodiment, the grouting assembly 7 includes at least one grouting pipe, which is longitudinally arranged and fixed along the inner sidewall of the bottom pile 1. Its upper end extends to the top of the bottom pile 1 or above the pile top for connection with external grouting pumping equipment, and its lower end extends into the bottom of the bottom pile 1 and is located within the axial area covered by the sealing sleeve 2. The lower outlet of the grouting pipe is connected to the inner cavity of the sealing sleeve 2. This connection can be achieved by opening a dedicated grouting hole on the sidewall of the bottom pile 1. The end of the grouting pipe is sealed to this grouting hole, allowing the grouting material to flow directly into the sealing sleeve 2. The grouting pipe can be made of corrosion-resistant metal or high-pressure hose to ensure stable delivery of grouting material in a seawater environment. During operation, after the force-applying assembly 5 pushes the sliding push plate 4 and the expansion material in the expansion body 3 is squeezed into the sealing sleeve 2 through the groove, the external grouting equipment is activated, pumping the grouting material through the grouting assembly 7 into the inner cavity of the sealing sleeve 2 on the outer periphery of the bottom of the bottom pile 1. After the grouting material enters the sealing sleeve 2, it permeates and fills the gaps between the expansion material particles or between the expansion material and the wall of the sealing sleeve 2 under the enclosure and constraint of the sealing sleeve 2, and gradually solidifies. The solidified grouting material and the expansion material bond together to form an integral whole, creating a composite and dense enlarged structure on the outer periphery of the bottom of the bottom pile 1. The filling and solidification effects of the grouting material not only enhance the integrity and compressive strength of the enlarged structure itself, but also allow some of the grout to seep outwards in small amounts into the surrounding soil along the groove through the grouting pressure, improving the bonding performance of the pile-soil interface.

[0038] Based on this, by integrating the grouting component 7 inside the bottom pile 1, grouting material is controllably injected into the sealing sleeve 2 after the expansion material has formed an initial enlarged outline. This transforms the enlarged structure from a single expansion material body into a composite body composed of expansion material and solidified grout. After the grouting material solidifies, it improves the structural density and overall strength of the enlarged head 9, compensates for the potential deficiency of the expansion material's own strength, enhances the reliability of force transmission between the enlarged head 9 and the bottom pile 1, and ultimately improves the stability of the vertical bearing capacity and pull-out resistance of the bottom pile 1.

[0039] In one embodiment, the expansion body 3 includes an expansion cavity 31 and a movable plate 32; the expansion cavity 31 is filled with expansion material; the movable plate 32 is vertically arranged and located on the side of the expansion cavity 31 away from the inner wall of the bottom pile 1; a plurality of sliding push plates 4 correspond one-to-one with the movable plates 32 of the plurality of expansion bodies 3, and the sliding push plates 4 are located at the lower part of the movable plate 32; wherein, the lower part of the expansion cavity 31 is provided with a discharge nozzle and corresponds to the groove; the sliding push plates 4 are used to drive the movable plate 32 to tilt and squeeze the expansion body 3 when they press the lower part of the movable plate 32 in the circumferential outward direction, so that the vertical cross section of the expansion body 3 is inverted cone shape.

[0040] In this embodiment, the expansion cavity 31 is a container structure for loading expansion material, installed on the inner wall of the bottom of the base pile 1, and pre-filled with expansion material. A discharge nozzle is provided at the bottom of the expansion cavity 31, the position of which corresponds to the position of the groove on the side wall of the base pile 1, allowing the extruded expansion material to directly enter the sealing sleeve 2 through the discharge nozzle and the groove. The discharge nozzle can be flat and elongated and can pre-penetrate the corresponding groove. The opening and closing of the discharge nozzle has a certain elasticity, requiring external extrusion pressure to open and release the internal expansion material. The movable plate 32 is vertically arranged on the side of the expansion cavity 31 away from the inner wall of the base pile 1, i.e., the inner side of the expansion cavity 31. The movable plate 32 serves as a side wall or independent partition of the expansion cavity 31 and can move relative to the expansion cavity 31. A sliding push plate 4 is provided correspondingly to the movable plate 32, and the sliding push plate 4 is located in the lower region of the movable plate 32. When the force-applying component 5 applies a thrust and drives the sliding push plate 4 to move outward in the circumferential direction, the outer circumferential side of the sliding push plate 4 first contacts the lower part of the movable plate 32 and applies a radially outward pushing force to the lower part of the movable plate 32. Since the thrust acts on the lower part of the movable plate 32 rather than being uniformly applied to the entire plate surface, the movable plate 32 rotates or tilts after being subjected to this lower thrust, manifested as the upper part of the movable plate 32 relatively contracting inward and the lower part relatively deflecting outward. The tilting movement of the movable plate 32 directly compresses the expansion material in the expansion cavity 31, and the degree of compression gradually increases from top to bottom, with the expansion material near the lower part of the movable plate 32 experiencing the greatest compressive force. Under the tilting compression of the movable plate 32, the vertical cross-sectional shape of the internal space of the expansion cavity 31 changes from an initial vertical rectangle or near-rectangular shape to an inverted cone shape that is larger at the top and smaller at the bottom. In this inverted conical spatial configuration, the expanded material tends to naturally converge towards the downward discharge nozzle under its own gravity, aligning with the direction of the concentrated extrusion force at the bottom. This allows the expanded material to be stably and smoothly discharged from the discharge nozzle at the bottom of the expansion cavity 31 and enter the sealing sleeve 2 through the slot. Compared to the extrusion method where the movable plate 32 advances in a parallel manner, the tilting motion of the movable plate 32 allows the upper space of the expansion cavity 31 to remain relatively large while the lower space continuously narrows. This avoids the problem of the upper expanded material being blocked at the top of the cavity due to the overall horizontal pushing and unable to be discharged downwards, thus making fuller use of the expanded material filled in the expansion cavity 31.

[0041] Based on this, this embodiment uses an asymmetrical force application method where the sliding push plate 4 acts on the lower part of the movable plate 32 to make the movable plate 32 tilt and squeeze the expansion cavity 31 into an inverted cone cross section. By utilizing the synergistic effect of the expansion material's own gravity and the concentrated extrusion force at the bottom, the smoothness and thoroughness of the expansion material's discharge to the outlet nozzle are improved, the residual amount in the cavity is reduced, and the expansion material is effectively transported into the sealing sleeve 2, providing a reliable material guarantee for the morphological integrity of the expanded structure.

[0042] In one embodiment, the expanded-base self-expanding pile also includes a limiting plate 8 installed on the inner sidewall of the bottom pile 1. The limiting plate 8 is located above the expansion cavity 31 and the movable plate 32. The limiting plate 8 is used to cooperate with the top of the movable plate 32 to prevent the top of the expansion cavity 31 from being squeezed out when the movable plate 32 is tilted.

[0043] In this embodiment, A limiting plate 8 is positioned above the expansion cavity 31 and the movable plate 32. It is fixed to the inner wall of the bottom pile 1 by welding or bolting, and is made of steel plate. The lower surface or inner edge of the limiting plate 8 serves as a constraint surface, located above the top of the movable plate 32. During actual operation, when the force-applying component 5 drives the sliding push plate 4 to press the lower part of the movable plate 32 outwards, the movable plate 32 tilts, its lower part deflects outwards to press the expansion cavity 31, while its upper part shifts inwards, away from the side wall of the bottom pile 1. Due to the tilt of the movable plate 32, the vertical cross-section of the expansion cavity 31 becomes an inverted cone shape, larger at the top and smaller at the bottom. The top area of ​​the expansion cavity 31 is expanded during the pressing process, and the entire expansion cavity 31 tends to move upwards due to the upward pressing force. Without constraint at the top, the top edge of the expansion cavity 31 may extend beyond the top of the movable plate 32 due to the combined effects of upward movement and its own expansion. This could cause the expanded material to not be extruded from the lower discharge cut, but instead to tumble over the top of the movable plate 32 and enter the internal area of ​​the bottom pile 1, resulting in material loss and uncontrolled extrusion path. The limiting plate 8 works in conjunction with the top of the movable plate 32 during its tilting movement, using its lower surface or inner edge to abut against the top area of ​​the expansion cavity 31, preventing the top of the expansion cavity 31 from tumbling upwards and inwards. This ensures that the top opening of the expansion cavity 31 is always pressed below the top of the movable plate 32 or maintains a closed contact with it. Thus, the top of the expansion cavity 31 is confined to the outer area of ​​the movable plate 32, and the expanded material can only be directionally extruded into the sealing sleeve 2 through the discharge cut and groove at the bottom of the expansion cavity 31 under the pressure of the lower part of the movable plate 32.

[0044] Based on this, by setting a limiting plate 8 to limit and constrain the top of the expansion cavity 31, the failure mode of the top of the expansion cavity 31 flipping over the top of the movable plate 32 and entering the inner side during the upward extrusion process is effectively prevented. This ensures that the extrusion path of the expansion material is always limited to discharge from the lower discharge cut, which improves the reliability of the material extrusion direction and the material utilization rate, and makes the filling and molding of the enlarged structure more stable and controllable.

[0045] In one embodiment, the limiting plate 8 is arc-shaped, and when the movable plate 32 is tilted, its top slides along the arc-shaped surface of the limiting plate 8.

[0046] In this embodiment, the limiting plate 8 is arc-shaped. The side of the arc-shaped limiting plate 8 facing the top of the movable plate 32 is machined into an arc surface, with the center of curvature of the arc surface pointing downwards. When the movable plate 32 tilts under the action of the sliding push plate 4, the top of the movable plate 32 does not translate inwards along a straight line, but rather generates an arc-shaped motion trajectory along with rotation. The arc-shaped surface on the limiting plate 8 adapts to the motion trajectory of the top of the movable plate 32. During the tilting process, the top of the movable plate 32 slides along this arc-shaped surface, forming an arc-shaped contact between the two, rather than a point contact or line contact. The curvature design of the arc-shaped surface allows the movable plate 32 to maintain a relatively close fit with the limiting plate 8 at different tilt angles, reducing sliding resistance and preventing the top of the movable plate 32 from getting stuck on the limiting plate 8. Simultaneously, the arc-shaped surface continuously provides back support at each stage of the movable plate 32's tilt, ensuring that the top of the expansion cavity 31 is always effectively sealed.

[0047] Based on this, the limiting plate 8 is designed as an arc. The continuous guiding and supporting effect provided by the arc surface further enhances the reliability of preventing the expansion material from being squeezed out from the top, making the directional discharge process of the expansion material more stable and controllable.

[0048] In one embodiment, the force-applying component 5 includes a linkage 51 and a drive unit 52; the linkage 51 is disposed at the inner bottom of the bottom pile 1 and connected to a plurality of sliding push plates 4; the drive unit 52 is disposed in the vertical direction and can move up and down; wherein, when the drive unit 52 moves downward, it can push the linkage 51 to move, and simultaneously drive the plurality of sliding push plates 4 to slide in the circumferential outward direction and squeeze the plurality of expansion bodies 3 respectively.

[0049] In this embodiment, the linkage 51 is located in the center of the inner bottom of the bottom pile 1, in the middle of the enclosing ring formed by the multiple sliding push plates 4, and is connected to each sliding push plate 4. Its main function is to distribute and transmit the driving force input by the downward movement of the drive unit 52 to each sliding push plate 4. The drive unit 52 is arranged vertically inside the bottom pile 1, and its upper end can extend to the top of the bottom pile 1 or above the pile top, so as to facilitate docking with the external force application device. The drive unit 52 as a whole can move up and down in the vertical direction.

[0050] During operation, the external force-applying device applies a downward force to the drive unit 52, causing the drive unit 52 to move downward. Its lower end acts on the linkage 51, applying a downward thrust to the linkage 51. Upon receiving this downward thrust, the linkage 51, through its internal transmission mechanism, converts the vertical motion into a horizontal outward sliding motion of multiple sliding push plates 4 simultaneously along the radial direction (i.e., the circumferential outward direction) of the bottom pile 1. This conversion mechanism is achieved, for example, by converting the change in component angle caused by the vertical motion into a radial displacement component. Since the linkage 51 simultaneously connects all the sliding push plates 4, once driven, it forces each sliding push plate 4 to move synchronously, eliminating the uneven force on the expansion body 3 that might result from the sequential movement of the sliding push plates 4.

[0051] Based on this, this embodiment achieves the synchronous conversion of a single-direction vertical operating force into multiple radial thrusts through the vertical downward movement of the drive unit 52 and the movement conversion of the linkage 51. The operation is simple and the force application is concentrated and controllable. The linkage 51 ensures the synchronicity and equality of the movements of each sliding push plate 4, so that multiple expansion bodies 3 are uniformly compressed. The expansion material enters the sealing sleeve 2 evenly through each slot, and finally forms a uniformly distributed enlarged structure on the outer periphery of the bottom of the bottom pile 1. This avoids the problem of uneven local enlargement leading to eccentricity of the pile foundation bearing and improves the stability of the enlarged bottom forming quality.

[0052] In one specific implementation of the linkage 51, the linkage 51 includes a vertical rod 511, a slider 512, and multiple connecting rods 513; the vertical rod 511 is fixedly installed on the inner bottom of the bottom pile 1; the slider 512 is slidably installed on the vertical rod 511 in the vertical direction; the multiple connecting rods 513 correspond one-to-one with multiple sliding push plates 4, one end of the connecting rod 513 is rotatably connected to the slider 512, and the other end of the connecting rod 513 is rotatably connected to the corresponding sliding push plate 4.

[0053] Specifically, the upright 511 is a vertically arranged rod, the lower end of which can be fixedly installed at the center of the bottom of the base pile 1 by welding or threaded connection. The axis of the upright 511 is parallel to the axis of the base pile 1, providing a precise vertical guide track for the slider 512. The slider 512 is a block-shaped component with a central through hole, fitted onto the upright 511, and can slide smoothly in the vertical direction along the outer surface of the upright 511. The number of connecting rods 513 is the same as the number of sliding push plates 4, and they are arranged in a one-to-one correspondence. One end of each connecting rod 513 is hinged to the slider 512 through a rotating connection pair (such as a pin or ball joint), and the other end is also hinged to the corresponding sliding push plate 4 through a rotating connection pair. In the initial state, when the slider 512 is in a higher position on the upright 511, the connecting rods 513 are in a relatively tilted posture, and the sliding push plate 4 is close to the center and in a standby position (see reference). Figure 3 and Figure 5When driven by an external force, as slider 512 moves vertically downward along the upright 511, connecting rod 513 gradually turns to a near-horizontal position under the influence of slider 512, pushing each sliding push plate 4 to slide outward radially along the bottom pile 1 simultaneously (see reference). Figure 4 and Figure 6 During this process, all connecting rods 513 are forced to move synchronously because they are connected to the same slider 512, and the radial displacement of each sliding push plate 4 is equal. The purely mechanical linkage characteristic of this linkage 51 eliminates the need for hydraulic or pneumatic branch control, resulting in high structural reliability. It is especially suitable for use in marine construction environments where complex pipeline maintenance is not possible.

[0054] Based on this, this embodiment uses a linkage mechanism 51 composed of a vertical rod 511, a slider 512, and multiple connecting rods 513 to efficiently convert the vertical linear motion of the slider 512 into the equidistant radial expansion motion of multiple sliding push plates 4. The structure is compact and the transmission path is short, avoiding the asynchronous problem caused by multiple points being driven separately.

[0055] Furthermore, the drive unit 52 can be a solid or hollow push rod. The lower end of the drive unit 52 is connected to the slider 512, and the two form a whole that moves synchronously in the vertical direction. The upper end of the drive unit 52 extends along the interior of the bottom pile 1 to above the top of the bottom pile 1 so as to connect with external force application devices such as hydraulic jacks, cylinders or screw pressurization mechanisms on the construction platform.

[0056] Please see Figure 8 This invention also provides a construction method for an enlarged-base self-expanding pile, applicable to the above-mentioned enlarged-base self-expanding pile. The construction method includes: S10. Hoist the bottom pile 1 into place and sink it into the seabed to the design elevation; S20, the force control component 5 provides a circumferential outward thrust, pushing multiple sliding push plates 4 to squeeze multiple expansion bodies 3 respectively, so that the expansion material in the expansion body 3 enters the sealing sleeve 2 through the groove; S30. Inject water into the sealing sleeve 2, so that the expansion material inside the sealing sleeve 2 expands when it comes into contact with water, driving the sealing sleeve 2 to expand outward and squeeze the surrounding soil. S40. Grouting material is injected into the sealing sleeve 2 through the grouting component 7. After the grouting material has cured, it and the expanded material together form multiple enlarged heads 9 distributed circumferentially on the outer periphery of the bottom of the bottom pile 1.

[0057] The specific construction process and principle of steps S10-S40 are as follows. First, pile preparation and pile driving operations are carried out: the pre-assembled bottom pile 1, containing all internal components, is hoisted into position on the construction vessel or platform, and then vertically driven into the seabed to the design elevation using a vibratory hammer or hydraulic static press. During the pile driving process, the expansion body 3, sliding push plate 4, and force application component 5 inside the bottom pile 1 are all in a non-operational initial state, and the sealing sleeve 2 is tightly attached to the outer wall of the bottom pile 1, without generating additional pile driving resistance.

[0058] Subsequently, the expansion material extrusion process is carried out: the force application component 5 provides a circumferential outward thrust, that is, the external force application device presses down the drive unit 52, which pushes multiple sliding push plates 4 to slide radially outward synchronously via the linkage 51. Each sliding push plate 4 squeezes the corresponding expansion body 3, causing the expansion material loaded inside the expansion body 3 to be extruded through the slot and enter the sealing sleeve 2 pre-fitted on the outer periphery of the bottom of the bottom pile 1. This process mechanically transports the expansion material from inside the bottom pile 1 to the closed space defined by the sealing sleeve 2. The sealing sleeve 2 plays a circumferential constraint and positioning role for the expansion material, so that the expansion material is distributed according to the preset area and prevents it from spreading disorderly into the surrounding seabed strata.

[0059] Next, the water-injection expansion process is carried out: water (seawater or freshwater) is delivered to the inner cavity of the sealing sleeve 2 on the outer periphery of the bottom of the bottom pile 1 through the water injection component 6 pre-installed inside the pile 1. After the water comes into contact with the expansion material that previously entered the sealing sleeve 2, the expansion material (water-swellable material) undergoes a water absorption and expansion reaction, and its volume increases rapidly. The expansion force acts on the inner wall of the sealing sleeve 2, driving the sealing sleeve 2 to expand outward, further compressing the surrounding seabed soil, and forming a larger radial expansion space on the outer periphery of the bottom of the pile 1. The hydration expansion process does not require continuous application of mechanical force, and the expansion direction is determined by the constraint of the sealing sleeve 2 and the soil reaction force, which is conducive to forming an expanded diameter profile that fits tightly with the soil.

[0060] Finally, the grouting and curing process is carried out: Through the grouting component 7 pre-installed inside the bottom pile 1, external grouting material (such as cement-based grout or resin grout) is pressurized and delivered into the inner cavity of the sealing sleeve 2. Under pressure, the grouting material fills the gaps between the expansion material particles, between the expansion material and the wall of the sealing sleeve 2, and between the sealing sleeve 2 and the soil, transforming the loose or porous expansion body 3 structure into a dense composite material structure. After curing, the grouting material combines with the expanded expansion material to form a single unit, forming multiple enlarged heads 9 (see reference) circumferentially around the bottom of the bottom pile 1, which are encased and bonded by the cured grout. Figure 7(As shown). These enlarged heads 9 utilize the continuous expansion tension of the expansion material to tightly compress the soil, and rely on the high bonding strength of the solidified grouting material to form a reliable connection with the pile body of the bottom pile 1 and the soil, ultimately achieving an enlarged base structure with a defined shape and enhanced bearing capacity. The entire construction process is carried out continuously after pile driving, without the need to pull up the pile body, change drilling tools, or perform additional hole cleaning. The procedures are closely linked, significantly shortening the time for offshore operations.

[0061] Based on this, the construction method of this invention integrates three process stages in an orderly manner: mechanical material pushing and positioning, water-swellable soil squeezing, and grouting and curing reinforcement. Initial filling and positioning of the expansive material is achieved through mechanical pushing; the expansion force generated by water swelling actively compacts and secondary enlarges the surrounding soil; and then, high-strength composite enlarged heads 9 are formed through grouting material curing. Finally, multiple circumferentially distributed, controllable, and structurally dense enlarged heads 9 are formed at the bottom of the bottom pile 1. This avoids the limitations of a single mechanical hole enlargement or single grouting process. The various stages complement and synergistically enhance each other, effectively improving the vertical bearing capacity and pull-out resistance of the offshore photovoltaic pile foundation.

[0062] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A self-expanding pile with an enlarged base, characterized in that, include: The bottom pile has multiple grooves that connect to the outside along the circumferential direction on the inner side wall of the bottom. A sealing sleeve is fitted onto the outer periphery of the bottom of the bottom pile and communicates with the inner bottom of the bottom pile through the groove. Multiple expansion bodies are arranged circumferentially on the inner sidewall of the bottom of the bottom pile, and correspond to the multiple grooves; Multiple sliding push plates are set at the bottom of the bottom pile and can abut against multiple expansion bodies in the circumferential outward direction. Each sliding push plate corresponds to one of the multiple expansion bodies. The force-applying component is located at the bottom of the bottom pile and in the middle of the enclosing ring formed by multiple sliding push plates, and can apply thrust in the circumferential outward direction; The force-applying component is used to push the plurality of sliding push plates to squeeze the plurality of expansion bodies respectively when it applies a thrust outward along the circumference, so as to drive the expansion material in the expansion body into the sealing sleeve through the groove.

2. The self-expanding pile with enlarged base according to claim 1, characterized in that, It also includes a water injection component, which is disposed inside the bottom pile and connected to the bottom outer periphery of the bottom pile. The water injection component is used to transport external water to a sealing sleeve on the bottom outer periphery of the bottom pile.

3. The self-expanding pile with enlarged base according to claim 1, characterized in that, It also includes a grouting assembly, which is disposed inside the bottom pile and communicates with the bottom outer periphery of the bottom pile. The grouting assembly is used to transport external grouting material to a sealing sleeve on the bottom outer periphery of the bottom pile.

4. The self-expanding pile with enlarged base according to claim 1, characterized in that, The expansion body includes: An expansion chamber, filled with expanding material; The movable plate is vertically arranged and located on the side of the expansion cavity away from the inner wall of the bottom pile; the multiple sliding push plates and the movable plates of the multiple expansion bodies correspond one-to-one, and the sliding push plates are located at the lower part of the movable plate; The lower part of the expansion cavity is provided with a discharge nozzle that corresponds to the slot. The sliding push plate is used to drive the movable plate to tilt and squeeze the expansion body when it presses the lower part of the movable plate in the circumferential outward direction, so that the vertical cross section of the expansion body is inverted cone shape.

5. The self-expanding pile with enlarged base according to claim 4, characterized in that, It also includes a limiting plate installed on the inner side wall of the bottom pile, the limiting plate being located above the expansion cavity and the movable plate; the limiting plate is used to cooperate with the top of the movable plate to prevent the top of the expansion cavity from being squeezed out when the movable plate is tilted.

6. The self-expanding pile with enlarged base according to claim 5, characterized in that, The limiting plate is arc-shaped, and when the movable plate is tilted, its top slides along the arc-shaped surface of the limiting plate.

7. The self-expanding pile with enlarged base according to claim 1, characterized in that, The force-applying component includes: A linkage is provided at the inner bottom of the bottom pile and connected to multiple sliding push plates; The drive unit is vertically oriented and can move up and down. The drive unit is used to push the linkage to move when it moves downward, and to drive the multiple sliding push plates to slide in the circumferential outward direction and squeeze the multiple expansion bodies respectively.

8. The self-expanding pile with enlarged base according to claim 7, characterized in that, The linkage includes: The upright is fixedly installed at the inner bottom of the bottom pile; The slider is slidably mounted on the upright in a vertical direction; Multiple connecting rods correspond one-to-one with the multiple sliding push plates. One end of each connecting rod is rotatably connected to the slider, and the other end of each connecting rod is rotatably connected to the corresponding sliding push plate.

9. The self-expanding pile with enlarged base according to claim 8, characterized in that, The driving unit is connected to the slider and is used to drive the slider to move vertically on the upright.

10. A construction method for an enlarged-base self-expanding pile, applied to the enlarged-base self-expanding pile as described in any one of claims 1 to 9, characterized in that, The construction method includes: The bottom piles were hoisted into place and sunk into the seabed to the design elevation; The force-applying component is controlled to provide a circumferential outward thrust, which pushes the plurality of sliding push plates to squeeze the plurality of expansion bodies respectively, so that the expansion material in the expansion body enters the sealing sleeve through the groove; Water is injected into the sealing sleeve, causing the expansion material inside the sealing sleeve to expand upon contact with water, thereby driving the sealing sleeve to expand outward and compress the surrounding soil. Grouting material is injected into the sealing sleeve through the grouting assembly. After the grouting material solidifies, it forms multiple circumferentially distributed enlarged heads on the outer periphery of the bottom of the pile together with the expanded material.

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