A solah fixed type umbrella-shaped bone spur prefabricated steel pipe pile and a construction method thereof

Abstract

The application discloses a solan fixed umbrella-shaped bone spur prefabricated steel pipe pile and a construction method, and solves the bottleneck of improving the bearing capacity of a traditional steel pipe pile. The steel pipe pile is integrally formed by a pile body shell, a lifting cable system, a locking stiffener, an umbrella-shaped bone spur expansion structure and the like in a factory. During construction, the pile body is first sunk to a predetermined position, the umbrella-shaped bone spur expansion is driven by a steel strand lifting device, the umbrella-shaped bone spur breaks the closed piece of the pile body and is locked into the surrounding soil, and a pile-soil mechanical engagement whole is formed. The core is to utilize the bone spur expansion to increase the effective stress section of the pile body, improve the compression and uplift bearing capacity, and there is no need to increase the pile diameter, increase the pile length or post-grouting. The application is simple in construction, high in efficiency, reliable in force transmission, suitable for various strata, especially suitable for high uplift requirement projects, and has the advantages of green environmental protection and economy, and can greatly reduce the construction cost.

Description

Technical Field

[0001] This invention belongs to the field of building foundation engineering technology, specifically relating to a novel precast steel pipe pile structure and construction method that uses lifting cables to mechanically unfold and fix the umbrella-shaped ribs inside the steel pipe pile, mechanically interlocking with the surrounding soil to increase the effective cross-section of the pile and improve the compressive and tensile bearing capacity of a single pile. Background Technology

[0002] In building foundation engineering, pile foundations are key components that bear the loads of the superstructure, and their load-bearing capacity directly affects the safety and stability of the building. Steel pipe piles are widely used in soft soil foundations such as silt, clay, silty clay, silt, and sand due to their advantages of high strength, convenient construction, and controllable quality.

[0003] The compressive bearing capacity of traditional steel pipe piles mainly depends on the strength of the pile material, the side friction, and the end resistance. In projects with soft soil and high bearing capacity requirements, it is often necessary to increase the pile diameter or length to meet design requirements. However, increasing the pile diameter leads to increased material consumption, increased construction difficulty, and higher project costs; increasing the pile length is limited by geological conditions, and deep pile construction carries the risk of displacement and is difficult to control in terms of quality.

[0004] To effectively improve the bearing capacity of steel pipe pile foundations, post-grouting technology is often used in engineering practice. This technology improves the working state of the pile-soil contact interface by grouting at the pile end or pile side. However, its grouting effect is easily constrained by multiple factors such as stratum permeability, grout ratio, and pressure control, resulting in poor stability.

[0005] Therefore, developing a new type of steel pipe pile foundation structure that can significantly improve the compressive and tensile bearing capacity of the pile without increasing the original pile diameter or pile length during construction, and that is convenient to construct, easy to control, and inexpensive, has become an urgent need in the industry. Summary of the Invention

[0006] Therefore, to address the aforementioned shortcomings of existing methods, this invention provides a cable-stayed, umbrella-shaped spur precast steel pipe pile and its construction method that increase the effective load-bearing cross-section of the pile. During construction, the pile is first hammered or pressed into a predetermined position in soft soil. Then, it is lifted by steel strands, causing the umbrella-shaped spur mechanism inside the pile to mechanically expand and penetrate the surrounding soil, securing it in place. After the spurs extend, they form a mechanically interlocking structure with the soil, effectively increasing the load-bearing cross-section of the pile and significantly improving its compressive and tensile bearing capacity. This overcomes the technical bottlenecks of traditional steel pipe piles, which rely on increasing pile diameter and length to enhance bearing capacity, and the unstable bearing capacity improvement effect of post-grouting technology. Consequently, it effectively reduces the construction cost of steel pipe piles, improves pile construction efficiency, and enhances the quality of the completed pile.

[0007] This invention is implemented as follows: a cable-stayed, umbrella-shaped spur precast steel pipe pile is constructed, characterized in that the spur steel pipe pile is precast in a factory as a single unit. The device consists of the following components: a pile body shell structure (1), a lifting cable system (2), a locking stiffening plate structure (3), an umbrella-shaped spur extension structure (4), a fixed locking disc structure (5), and a head stiffening plate (6). The steel strands (201) in the lifting cable system (2) pass through the holes in the locking stiffening plate structure (3) and the umbrella-shaped spur extension structure (4). The lifting clamp (202) limits and supports the umbrella-shaped spur extension structure (4), and the anti-fall clamp (203) holds the top of the steel pipe stiffening ring (303) of the uppermost locking stiffening plate structure (3) to prevent it from falling, thus achieving positioning. The steel strands (201) above the anti-fall clamp (203) are held on the fixed locking disc structure (5), ensuring operating space for subsequent lifting. Finally... Then, the locking stiffening plate structure (3), the umbrella-shaped bone spur extension structure (4), the fixed locking disc structure (5), the head stiffening plate (6) and the pile body shell structure (1) are welded together to form an integral steel pipe pile.

[0008] Furthermore, the outer shell structure (1) of the pile body is composed as follows: a circular steel pipe (101) is welded to a conical pile tip (104) as a whole; a circular steel pipe (101) has a pre-reserved pipe body protrusion hole (102) on its side wall; and a closed thin steel sheet (103) is welded to the outside of the pre-reserved pipe body protrusion hole (102) to form a closed steel pipe pile shell.

[0009] Furthermore, the lifting cable system (2) consists of steel strands (201), lifting clamps (202), and anti-fall clamps (203). Each lifting clamp (202) is fixed to the steel strands (201) and placed at the lower part of each umbrella-shaped spur extension structure (4). The anti-fall clamps (203) are fixed to the steel strands (201) and placed at the uppermost locking stiffening plate structure (3). The spacing between the lifting clamps (202) is the same as the spacing between the locking stiffening plate structures (3).

[0010] Furthermore, the locking stiffening plate structure (3) consists of a circular single-layer stiffening plate (301), a rectangular stiffening plate (302), a steel pipe stiffening ring (303), and a strut positioning double lug (304). The spacing between each locking stiffening plate structure (3) is ≥ 5 times the pile diameter. The circular single-layer stiffening plate (301) is welded to the inner side of the pile shell structure (1) and is perpendicular to the pile shell. The diameter of the steel pipe stiffening ring (303) is larger than the inner ring diameter of the circular single-layer stiffening plate (301). The steel pipe stiffening ring (303) is welded to the upper part of the circular single-layer stiffening plate (301). The rectangular stiffening plates (302) are evenly distributed along the circumferential direction with the center of the circular single-layer stiffening plate (301) as the base point. They are welded and fixed to the top surface of the circular single-layer stiffening plate (301), the side of the steel pipe stiffening ring (303), and the inner side of the pile shell structure (1). The strut positioning double lugs (304) are arranged in a straight line along the center of the circular single-layer stiffening plate (301) and welded to the edge of the inner ring opening at the bottom of the circular single-layer stiffening plate (301).

[0011] Furthermore, the umbrella-shaped bone spur extension structure (4) consists of a through-hole steel pipe (401), a locking buckle (402), a steel bone spur (403), a limiting row of locking teeth (404), a support rod limiting steel bar (405), a bone spur positioning ring (406), and a bone spur support rod (407). The locking buckle (402) is arranged in a straight row along the center of the through-hole steel pipe (401) and welded to the top thickness surface of the through-hole steel pipe (401). The bone spur positioning ring (406) is welded and positioned on the lower side wall of the through-hole steel pipe (401). The top surface of the protruding end of the steel bone spur (403) is flat, with the tip facing outward and downward; the top surface of the middle standard section is flat, with the tip facing downward; the root is a ring, which is limited to the bone spur positioning ring (406) to ensure that the root can rotate. The limiting row of locking teeth (404) is welded and fixed to the top plane of the steel bone spur (403). The length of the two support rod limiting steel bars (405) is greater than the length of the limiting positive row teeth (404), and they are welded parallel to the top plane of the steel spur (403), with a gap between the steel bars. One end of the spur support rod (407) is looped onto the support rod positioning double ear (304) to ensure that the root can rotate, and the other end is a T-shaped connector that passes through the gap and is limited between the two support rod limiting steel bars (405) and the limiting positive row teeth (404).

[0012] Furthermore, the fixed locking disc structure (5) consists of a circular single-layer steel plate (501) and a circular steel strand lead-out outlet clamp (502), with the circular steel strand lead-out outlet clamp (502) welded to the circular single-layer steel plate (501). The steel strand (201) can pass through the opening in the middle of the circular single-layer steel plate (501), be led out along the lead-out outlet of the circular steel strand lead-out outlet clamp (502), and be clamped in the lead-out outlet clamp strip. The remaining length of the steel strand (201) can be coiled on the circular single-layer steel plate (501).

[0013] Furthermore, the head stiffening plate (6) is composed of a circular single-layer stiffening plate (601), a rectangular stiffening plate (602), a steel pipe stiffening ring (603), and a sealing plate (604). The circular single-layer stiffening plate (601) is welded to the inner top of the pile shell structure (1) and is perpendicular to the pile shell. The diameter of the steel pipe stiffening ring (603) is equal to the inner ring of the circular single-layer stiffening plate (601). The diameter of the steel pipe stiffening ring (603) is welded to the lower part of the circular single-layer stiffening plate (601). The rectangular stiffening plate (602) is evenly distributed along the circumferential direction with the center of the circular single-layer stiffening plate (601) as the base point, and is welded and fixed to the bottom surface of the circular single-layer stiffening plate (601), the side of the steel pipe stiffening ring (603), and the inner side of the pile shell structure (1). After the cable is lifted into place, the opening of the circular single-layer stiffening plate (601) is welded and sealed before the pile top cap is poured.

[0014] Furthermore, the steel bar sleeve (8) is arranged in a circumferential row along the center of the head stiffening plate (6) and welded to the top of the head stiffening plate (6).

[0015] Furthermore, the steel bar (9) is connected to the steel bar sleeve (8) by a threaded connection to ensure the anchorage length of the pile and the upper foundation, forming an integral whole to transmit tension.

[0016] A construction method for precast steel pipe piles with cable-stayed umbrella-shaped bone spurs, characterized by the following specific operations: Step 1: Pile Foundation Design Based on the engineering geological survey report, the load requirements of the superstructure, and the design value of the bearing capacity, the diameter, wall thickness, pile length, and spur arrangement scheme of the spur steel pipe pile are determined. The spur arrangement scheme includes key parameters such as the number of spurs, the distribution position of the spurs along the height of the pile, the extension length of the spurs, and the angle between the spurs and the axis of the pile. Step 2: Pile Construction and Inspection (1) The following components are processed and manufactured in the factory: pile body shell structure (1), lifting cable system (2), locking stiffening plate structure (3), umbrella-shaped bone spur extension structure (4), fixed locking disc structure (5), end cap stiffening plate (6); (2) Set up a vertical support frame and place the locking stiffening plate structure (3), umbrella-shaped bone spur extension structure (4), and fixed locking plate structure (5) in layers according to the designed vertical elevation; (3) Install and fix the anti-fall clamp (203) on the steel strand (201) in the lifting cable system (2), then pass the lower steel strand of the anti-fall clamp (203) through the middle hole of the locking stiffening plate structure (3) and the umbrella-shaped bone spur extension structure (4) in sequence, and finally install and fix the lifting clamp (202) on the lower part of the umbrella-shaped bone spur extension structure (4) to support the umbrella-shaped bone spur extension structure (4); repeat the above operation according to the number of locking stiffening plate structures (3) and umbrella-shaped bone spur extension structures (4) set; (4) Measure the distance between the locking buckle (402) and the locking stiffening plate structure (3) in the umbrella-shaped spur extension structure (4) to ensure that the distance between each adjacent component is consistent. If they are inconsistent, readjust the position of the lifting clamp (202) to ensure that the distance is consistent, and record the final distance value A; (5) Adjust each steel spike (403) sequentially to align with the reserved opening, ensuring that the end of the steel spike (403) is limited to the wall thickness of the reserved tube body protruding from the side wall (102); (6) The outer shell structure (1) of the pile body is disassembled into sections and then welded to the locking stiffening plate structure (3), the umbrella-shaped bone spur extension structure (4), the fixed locking plate structure (5), and the head stiffening plate (6) in sequence to form an integral steel pipe pile; (7) Weld the closed thin steel sheet (103) to the outside of the reserved pipe body protrusion hole (102) to form a closed steel pipe pile shell; (8) Inspect verticality and flatness; Step 3: Transportation and on-site storage of pile foundations The prefabricated steel pipe piles with spurs are transported to the construction site. During transportation, a special transport frame is used to secure the piles and prevent deformation or damage. Upon arrival at the site, the piles are stored in a designated area, supported by wooden blocks to prevent direct contact with the ground. Step 4: Pile Foundation Positioning Based on the designed pile positions, the site is leveled and surveyed, the center point of the pile position is marked, and the coordinates and elevation of the pile position are checked to ensure that the pile position deviation is controlled within the design allowable range. Step 5: Pile driving construction (1) Prepare static pile driving equipment or hammer pile driving equipment according to the pile driving process requirements, check the equipment operation status, and verify whether the pile driving force or hammer energy meets the design requirements. (2) The steel pipe piles with spurs are driven to the design elevation using either static pile driving or hammer driving. Static pile driving uses hydraulic jacks to apply continuous pressure to the pile head, causing the pile to gradually sink into the soil. Hammer driving uses an impact hammer to apply impact force to the pile head, causing the pile to sink into the soil under the impact force. (3) During the pile driving process, the bone spike locking mechanism is located inside the pile body. The closed thin steel sheet (103) closes the reserved tube body protrusion hole (102) to prevent soil, mud and impurities from entering the pile body and ensure that the bone spike expansion mechanism operates in a clean environment. The steel strand group is fixed inside the pile body by the line group anti-fall clip (203) to prevent the steel strand from falling due to vibration or impact during the pile driving process. (4) After the pile is driven to the design elevation, stop the pile driving or hammering operation, measure the pile top elevation and the verticality of the pile body, and confirm that the pile driving quality is qualified. After the pile is driven, the pile body of the spur steel pipe pile forms initial contact with the surrounding soil. At this time, the pile side friction and pile end resistance have been formed, but the spurs have not yet extended. The effective section of the pile body is the circular section corresponding to the outer diameter of the spur steel pipe pile. Step 6: Steel strand lifting and bone spur expansion construction (1) After the pile driving is completed, manually pull out the upper steel strand (201) of the fixed locking plate structure (5) from the middle opening of the head stiffening plate (6); (2) Install a through-type tension jack (7) at the pile head position; the jack base is supported on a circular bearing steel plate (601), and a limiter is set on the pile top to limit the plane position of the jack and prevent the jack from slipping; (3) Pass the steel strand (201) through the through-type tensioning jack (7), straighten it vertically, and let the tensioning jack fix and clamp the steel strand (201), and record the initial position; (4) Start the tensioning jack using the CNC lifting system to lift the steel strand (201). The tension force is transmitted to the lifting clamp (202) through the steel strand. The lifting clamp (202) transmits the tension force to the umbrella-shaped bone spur extension structure (4) and drives it to move upward.

[0017] (5) As the umbrella-shaped spur expansion structure (4) rises upward, the through-core steel pipe (401) and the spur positioning ring (406) also rise upward simultaneously, causing the steel spur (403) to extend outward toward the opening, piercing the closed thin steel sheet (103) and splitting into the soil around the pile. As the steel spur (403) expands outward, the T-shaped connector at the end of the spur strut (407) gradually retreats along the top arc surface of the limiting positive row of locking teeth (404) and then sinks into the locking tooth groove. As the steel strand (201) drives the through-core steel pipe (401) to rise, the locking buckle (402) is finally lifted and locked into the inner ring opening of the circular single-layer stiffening plate (301). At this time, the spur strut (407) The steel spur (403) is locked in the groove of the limiting positive row of teeth (404). At this time, the steel spur (403) and the spur support rod (407) form a stable triangular support structure; the construction principle of the remaining umbrella-shaped spur extension structure (4) is the same as the above method. (6) Raise the criteria for determining termination: ①The final judgment scheme is that the length of the steel strand lifting should be equal to the distance A between the locking buckle (402) and the locking stiffening plate structure (3) during pile manufacturing.

[0018] ② The CNC lifting system displays a sudden increase in lifting force; ③ The CNC lifting system displays a sudden change in lifting displacement to 0; (7) Terminate the lifting, remove the jack, and put the excess steel strand (201) back from the opening in the middle of the head stiffening plate (6), and secure it to the fixed locking plate structure (5). (8) Seal the opening of the annular single-layer stiffening plate (601) by welding with a sealing plate (604); Step 7: Pile Foundation Bearing Capacity Testing and Acceptance According to the specifications, the vertical bearing capacity and tensile bearing capacity of the precast steel pipe piles with cable-stayed umbrella-shaped spurs that have been constructed were tested.

[0019] Step 8: Construction of pile head anchorage reinforcement The steel sleeve (8) is arranged in a circumferential row along the center of the head stiffening plate (6) and welded to the top of the head stiffening plate (6). The steel bar (9) is then connected to the steel sleeve (8) by a threaded connection to ensure the anchorage length between the pile and the upper foundation, forming a whole and transmitting tensile force. Step 9: Construction of structural components above the pile head The pile cap or base slab concrete is poured on the top of the pile, and the reliable connection between the pile foundation and the superstructure is achieved through the steel sleeve (8) and the connecting steel bar (9).

[0020] The core working principle of this application is: 1. Prefabricated integrated construction principle: The steel strand lifting cable system (2) is used to connect multiple sets of umbrella-shaped bone spur extension structures (4). The anti-fall clamps (203) of the lifting cable system (2) are used to form a whole with the prefabricated steel pile formed by the pile shell structure (1), locking stiffening plate structure (3), fixing lock plate structure (5) and end cap stiffening plate (6).

[0021] 2. Lifting stage pile spur expansion principle: After the pile is driven and positioned, a through-core lifting system (2) is set at the top of the pile to apply steel strand lifting force, drive the multiple sets of umbrella-shaped spur expansion structures (4) inside the pile body to expand and extend outward from the reserved hole (102) on the side of the pile and anchor into the surrounding soil to form a mechanically interlocking pile-soil composite whole. At the same time, the umbrella-shaped spur expansion structure (4) is fixed in the locking stiffening plate structure (3). The steel spurs (403) inside the pile body and the spur support rod (407) form a stable triangular rod statically determinate structure system.

[0022] 3. Self-balancing principle during the lifting stage: A through-type tension jack (7) is installed at the top of the pile. When the lifting force is applied to the steel strand (201), a balanced force system is formed inside the pile. At this time, the upward pulling force on the steel strand (201) and the downward pressure of the jack (7) on the top of the pile form a positive and negative symmetrical force. Finally, the upward pulling force of the steel strand will be converted into the axial pressure of the pile body.

[0023] 4. Self-balancing principle of bone spurs: The steel bone spurs (403) and bone spur struts (407) inside the pile body form a stable triangular statically determinate structural system, and are arranged in a circular alignment, with consistent directions; the horizontal forces of all bone spur struts (407) are controlled by locking The stiffening plate structure (3) achieves circumferential force balance, and all steel spikes (403) achieve circumferential force balance through the through steel pipe (401).

[0024] 4. Principle of improving the pull-out bearing capacity of the pile: When the pile is subjected to pull-out force, the top plane of the multiple sets of bone spikes extending from the outer shell of the pile will be resisted by the shear strength of the soil around the pile (11), forming a pile-soil composite expansion effect, which in turn significantly improves the pull-out bearing capacity of the pile.

[0025] 5. Principle of Improving Pile Compressive Bearing Capacity: The multiple sets of protruding spurs from the pile shell significantly increase the friction coefficient between the smooth pile shell and the surrounding soil, thus increasing the pile's side friction resistance. Simultaneously, the bottommost set of spurs increases the end-support area, enhancing the end resistance. In summary, the pile's compressive bearing capacity is significantly improved.

[0026] The present invention has the following advantages: 1. Significantly increased tensile strength: See Figure 18 By extending outward and anchoring into the soil with the help of the bone spur extension mechanism, under the same pile diameter and pile length conditions, the pile-soil integration effect is utilized to expand the effective pile diameter and frictional side area, thereby significantly improving the pile's tensile bearing capacity.

[0027] 2. Significantly improved compressive bearing capacity: By utilizing multiple sets of spurs along the pile body, the friction coefficient between the smooth pile shell and the surrounding soil can be significantly increased, thereby increasing the pile's side friction resistance. Simultaneously, the bottommost set of spurs at the pile bottom expands the end-support area, enhancing the end resistance and ultimately resulting in a substantial increase in the pile's compressive bearing capacity.

[0028] 3. Simple construction process: The construction process employs factory prefabrication, on-site static pile driving, pile head tensioning and expansion of the spur, testing and inspection, and sealing of the pile head with anchor reinforcement. This avoids construction and quality problems caused by borehole collapse during rotary excavation in sandy or soft soil strata, avoids the complex construction procedures and quality control difficulties of enlarged-base piles, and avoids the grout diffusion control challenges of post-grouting technology. The spur expansion construction is simple to operate, with short single-pile tensioning and lifting time, resulting in high construction efficiency.

[0029] 4. The force transmission of the pile body is safe and reliable: The single steel spur inside the pile body, along with the spur struts, expands to form a stable triangular statically determinate structural system, ensuring stable stress distribution and reliable safety. The horizontal forces of multiple annular, aligned spur struts in the same group are balanced circumferentially through a locking stiffening plate structure, and the circumferential forces of multiple annular, aligned steel spurs in the same group are also balanced circumferentially through a through-core steel pipe. This results in symmetrical and balanced overall force transmission, ensuring safety and reliability.

[0030] 5. Wide range of applications: This structure is suitable for various geological conditions, including soft soil, silt, sand, and silty clay, and is particularly suitable for projects with high pull-out resistance requirements. Compared with enlarged-base piles, this invention is not limited by geological conditions, and compared with post-grouting technology, this invention is not affected by the permeability of the geological formation.

[0031] 6. High structural safety: The pile body adopts a circular steel pipe structure combined with multiple sets of stiffening ribs, resulting in high overall rigidity and strong bending resistance. The force transmission path of the spur extension mechanism is clear, the force is well-defined, and the locking mechanism is reliable, ensuring the safety and stability of the pile foundation during use.

[0032] 7. Green and environmentally friendly: The bone spur expansion process is mechanical, which does not generate environmental pollution such as vibration, noise, or mud. It causes little disturbance to the surrounding soil, making it suitable for projects with high environmental protection requirements and in line with the concept of green construction.

[0033] 8. Good engineering economics Under the same bearing capacity requirements, the present invention can reduce the number of piles, shorten the pile length, reduce the pile diameter, significantly reduce the amount of steel used, and reduce the project cost. Attached Figure Description

[0034] Figure 1 This is a structural diagram of the precast pile body in its initial state; Figure 2 This is a diagram of the pile structure during the bone spur expansion stage; Figure 3 This is a structural diagram of the pile body during the fixed locking stage; Figure 4 This is a structural diagram of the precast pile shell in its initial state; Figure 5 This is a structural diagram of the lifting steel strand; Figure 6 This is a schematic diagram showing the connection between the lifting steel strand and the umbrella-shaped bone spur extension structure; Figure 7 This is a bottom view of the locking stiffening plate; Figure 8 This is a top view of the locking stiffening plate; Figure 9 This is a top view of the umbrella-shaped osteophyte extension structure in a locked state; Figure 10 This is a bottom view of the umbrella-shaped osteophyte extension structure in a locked state; Figure 11 This is a detailed view of the local locking area of ​​the umbrella-shaped osteophyte extension structure; Figure 12 This is a detailed view of the support structure of the umbrella-shaped osteophyte. Figure 13 This is a diagram illustrating the expansion process of a single bone spur. Figure 14 This is a diagram of the steel ring snap-fit ​​structure for the expansion structure of the umbrella-shaped bone spur; Figure 15 This is a structural diagram of a fixed locking disc; Figure 16 This is a top view of the head stiffening plate; Figure 17 This is a bottom view of the head stiffening plate; Figure 18 This is a schematic diagram of the interaction between the bone spurs and the soil around the pile in the pull-out state; The components are: 1-Pile shell structure, 2-Lifting cable system, 3-Locking stiffening plate structure, 4-Umbrella-shaped spur extension structure, 5-Fixing locking disc structure, 6-End stiffening plate, 7-Through-type tension jack, 8-Reinforcing steel sleeve, 9-Reinforcing steel, 10-Soil surrounding the pile. 101- Circular steel pipe; 102- Pre-reserved opening for the pipe body on the side wall; 103- Sealed thin steel sheet; 104- Conical pile tip. 201 - Steel strand, 202 - Lifting clamp, 203 - Fall arrestor clamp 301 - Circular single-layer stiffening plate; 302 - Rectangular stiffening plate; 303 - Steel pipe stiffening ring; 304 - Double lugs for strut positioning. 401-Through-core steel pipe, 402-Locking buckle, 403-Steel spur, 404-Limiting and aligning teeth, 405-Supporting rod limiting steel bar, 406-Spur positioning ring, 407-Spur support rod 501 - Circular single-layer steel plate; 502 - Circular steel strand lead-out clamp. 601-Circular single-layer stiffening plate, 602-Rectangular stiffening plate, 603-Steel pipe stiffening ring, 604-Sealing plate. Detailed Implementation

[0035] The following will be combined with the appendix Figures 1-18This invention will be described in detail, and the technical solutions in the embodiments of this invention will be clearly and completely described. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0036] This invention provides a cable-fixed umbrella-shaped spur precast steel pipe pile, such as... Figures 1-18 The following method can be used to implement the spur steel pipe pile: The spur steel pipe pile is prefabricated in the factory and is composed of the following components: pile shell structure (1), lifting cable system (2), locking stiffening plate structure (3), umbrella-shaped spur extension structure (4), fixed locking plate structure (5), and end cap stiffening plate (6). The steel strand (201) in the lifting cable system (2) passes through the middle hole of the locking stiffening plate structure (3) and the umbrella-shaped spur extension structure (4). The lifting clamp (202) is used to limit and support the umbrella-shaped spur extension structure (4). The anti-fall clamp (203) is used to hold the top of the steel pipe stiffening ring (303) of the uppermost locking stiffening plate structure (3) to prevent it from falling and achieve positioning. The steel strand (201) above the anti-fall clamp (203) is clamped on the fixed locking plate structure (5) to ensure the operating space for later lifting. Finally, the locking stiffening plate structure (3), the umbrella-shaped bone spur extension structure (4), the fixed locking disc structure (5), the head stiffening plate (6) and the pile body shell structure (1) are welded together to form an integral steel pipe pile.

[0037] See Figure 4 The outer shell structure (1) of the pile body is composed as follows: a circular steel pipe (101) is welded to a conical pile tip (104) as a whole; a circular steel pipe (101) has a pre-reserved pipe body protrusion hole (102) on its side wall; and a closed thin steel sheet (103) is welded to the outside of the pre-reserved pipe body protrusion hole (102) to form a closed steel pipe pile shell.

[0038] See Figure 5 and Figure 6 The lifting cable system (2) consists of steel strands (201), lifting clamps (202), and anti-fall clamps (203). Each lifting clamp (202) is fixed to the steel strands (201) and placed at the bottom of each umbrella-shaped spur extension structure (4). The anti-fall clamps (203) are fixed to the steel strands (201) and placed at the top of the locking stiffening plate structure (3). The spacing between the lifting clamps (202) is the same as the spacing between the locking stiffening plate structures (3).

[0039] See Figure 7 and Figure 8The locking stiffening plate structure (3) consists of a circular single-layer stiffening plate (301), a rectangular stiffening plate (302), a steel pipe stiffening ring (303), and a strut positioning double lug (304). The spacing between each locking stiffening plate structure (3) is ≥ 5 times the pile diameter. The circular single-layer stiffening plate (301) is welded to the inner side of the pile shell structure (1) and is perpendicular to the pile shell. The diameter of the steel pipe stiffening ring (303) is larger than the inner ring diameter of the circular single-layer stiffening plate (301). The steel pipe stiffening ring (303) is welded to the upper part of the circular single-layer stiffening plate (301). The rectangular stiffening plates (302) are evenly distributed in a positive column along the circumferential direction with the center of the circular single-layer stiffening plate (301) as the base point. They are welded and fixed to the top surface of the circular single-layer stiffening plate (301), the side of the steel pipe stiffening ring (303), and the inner side of the pile shell structure (1). The strut positioning double lugs (304) are arranged in a straight line along the center of the circular single-layer stiffening plate (301) and welded to the edge of the inner ring opening at the bottom of the circular single-layer stiffening plate (301).

[0040] See Figures 9-14 The umbrella-shaped bone spur extension structure (4) consists of a through-hole steel pipe (401), a locking buckle (402), a steel bone spur (403), a limiting aligned locking tooth (404), a support rod limiting steel bar (405), a bone spur positioning ring (406), and a bone spur support rod (407). The locking buckle (402) is arranged in a straight line along the center of the through-hole steel pipe (401) and welded to the top thickness surface of the through-hole steel pipe (401). The bone spur positioning ring (406) is welded and positioned to the lower side wall of the through-hole steel pipe (401). The steel bone spur (403) protrudes from the top end. The surface is flat, with the tip facing outwards and downwards; the top surface of the middle standard section is flat, with the tip facing downwards; the root is a ring, which is limited to the bone spur positioning ring (406) to ensure that the root can rotate. The limiting positive row of locking teeth (404) is welded to fix the top plane of the steel bone spur (403). The length of the two support rod limiting steel bars (405) is greater than the length of the limiting positive row of locking teeth (404), and they are welded parallel to the top plane of the steel bone spur (403), with a gap between the steel bars. One end of the bone spur support rod (407) is looped to the support rod positioning double ear plate (304) to ensure that the root can rotate, and the other end is a T-shaped connector that passes through the gap and is limited between the two support rod limiting steel bars (405) and the limiting positive row of locking teeth (404).

[0041] See Figure 15 The fixed locking disc structure (5) consists of a circular single-layer steel plate (501) and a circular steel strand lead-out outlet clamp (502), which is welded to the circular single-layer steel plate (501). The steel strand (201) can pass through the opening in the middle of the circular single-layer steel plate (501), be led out along the lead-out outlet of the circular steel strand lead-out outlet clamp (502), and be clamped in the lead-out outlet clamp. The remaining length of the steel strand (201) can be coiled on the circular single-layer steel plate (501).

[0042] See Figure 16 and Figure 17 The head stiffening plate (6) is composed of a circular single-layer stiffening plate (601), a rectangular stiffening plate (602), a steel pipe stiffening ring (603), and a sealing plate (604). The circular single-layer stiffening plate (601) is welded to the inner top of the pile shell structure (1) and is perpendicular to the pile shell. The diameter of the steel pipe stiffening ring (603) is equal to the inner diameter of the circular single-layer stiffening plate (601). The steel pipe stiffening ring (603) is welded to the lower part of the circular single-layer stiffening plate (601). The rectangular stiffening plates (602) are evenly distributed along the circumferential direction with the center of the circular single-layer stiffening plate (601) as the base point, and are respectively welded and fixed to the bottom surface of the circular single-layer stiffening plate (601), the side surface of the steel pipe stiffening ring (603), and the inner side of the pile shell structure (1). After the cable is lifted into place, before the pile cap is poured, the opening of the circular single-layer stiffening plate (601) is welded and sealed.

[0043] See Figure 13 The steel bar sleeve (8) is arranged in a circumferential row along the center of the head stiffening plate (6) and welded to the top of the head stiffening plate (6).

[0044] See Figure 13 The steel bar (9) is connected to the steel bar sleeve (8) by a threaded connection to ensure the anchorage length of the pile and the upper foundation, forming a whole and transmitting tensile force.

[0045] Regarding the construction method of cable-fixed umbrella-shaped spur precast steel pipe piles, the following two embodiments are provided. (1) Example 1: This example uses a high-rise building foundation project in a coastal area as a case study. The project site is located in a soft soil region with plastic clay soil of approximately 40 meters thickness, interspersed with sand layers, making the geological conditions particularly complex and the foundation bearing capacity low. To ensure the safety of the foundation structure, pile foundations were adopted for design and construction.

[0046] Step 1: Pile Foundation Design 1. According to the engineering geological survey report, the bearing capacity of the plastic clay foundation is... =120 kPa, standard value of ultimate side resistance =53KPa, the ultimate end resistance is negligible. Due to the large load on the superstructure, traditional shallow foundations cannot meet the bearing capacity requirements. According to the superstructure load requirements, 100 piles with a diameter of 1 meter should be arranged (Scheme 1), but according to the code, the minimum spacing of the piles is 3d (i.e., 3 meters), and 100 piles cannot be arranged within the main building's plan projection area. Therefore, without reducing the bearing capacity, 0.8-meter diameter spur piles are selected (Scheme 2), with a minimum spacing of 3d (i.e., 2.4 meters), which is exactly enough to arrange 100 piles.

[0047] Option 1: Vertical bearing capacity of 1m diameter steel pipe piles.

[0048] =3.14x1x53x25=4160kN.

[0049] Option 2: Vertical bearing capacity of 0.8m bone spur steel pipe piles.

[0050] =3.14x0.8x1.25x53x25=4160kN; The coefficient for increasing the lateral resistance of the bone spur pile is taken as 1.25.

[0051] 2. According to the vertical load requirements of the pile, the diameter of the bone-spur steel pipe pile is 80cm, the wall thickness is 2cm, and the steel type is Q355.

[0052] 3. Due to the bone spurs, the vertical bearing capacity increases by 864kN. Four sets of bone spurs are installed, each set consisting of eight steel spurs. One set is installed 1m from the pile tip, and another set is installed every 5 meters thereafter, for a total of 32 bone spurs. Each bone spur bears a vertically increased load of 26kN. Using triangular member bending and compressive strength calculations, the bone spurs are selected to be 50cm long, with a 5cm flat top, made of Q355 steel. The lower part and protruding ends are equipped with blade edges. The distance A between the locking buckle and the locking stiffening plate in the umbrella-shaped bone spur extension structure is 40cm. The angle between the bone spur and the vertical line inside the pile is 36.87 degrees, and the steel is Q355. After extension, the bone spurs are perpendicular to the pile length, protruding 0.2m from the outer wall of the pile. Each set consists of eight steel spurs, with one set installed 1m from the pile tip, and another set every 5 meters thereafter, for a total of four sets. The strut has a cross-section of 2cm wide x 4cm high and a length of 45cm, made of Q355 steel. The remaining locking stiffening plate structure, fixed locking disc structure, and end cap stiffening plate components are all made of 2cm thick Q355 steel plate. The steel strand used is 1×7-15.20-1860, with a maximum lifting force of 260kN.

[0053] Step 2: Pile Construction and Inspection (See also) Figure 1 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 16 , Figure 17 ) 1. According to the design requirements, the following components are processed and manufactured in the factory: pile body shell structure (1), lifting cable system (2), locking stiffening plate structure (3), umbrella-shaped spur extension structure (4), fixed locking disc structure (5), and end cap stiffening plate (6). Each component is treated with rust and corrosion prevention.

[0054] 2. Set up a vertical support frame and arrange the 4 sets of locking stiffening plate structures (3), 4 sets of umbrella-shaped spur extension structures (4), and fixed locking disc structures (5) from bottom to top according to the design vertical elevation in the following order: umbrella-shaped spur extension structure 1 - locking stiffening plate structure 1 - umbrella-shaped spur extension structure 2 - locking stiffening plate structure 2 - umbrella-shaped spur extension structure 3 - locking stiffening plate structure 3 - umbrella-shaped spur extension structure 4 - locking stiffening plate structure 4 - fixed locking disc structure.

[0055] 3. Install and fix the anti-fall clamp (203) on the steel strand (201) in the lifting cable system (2). Then, pass the lower steel strand of the anti-fall clamp (203) through the holes in the middle of the four sets of locking stiffening plate structures (3) and umbrella-shaped rib extension structures (4) in sequence. Finally, install and fix the lifting clamp (202) on the lower part of each set of umbrella-shaped rib extension structures (4) to support the umbrella-shaped rib extension structures (4). Repeat the above operation according to the number of locking stiffening plate structures (3) and umbrella-shaped rib extension structures (4) set.

[0056] 4. Measure the distance between the locking buckle (402) and the locking stiffening plate structure (3) in the umbrella-shaped spur extension structure (4) to ensure that the distance between each adjacent component is consistent. If they are inconsistent, readjust the position of the lifting clamp (202) to ensure that the distance is consistent, and record the final distance value A=40cm.

[0057] 5. Adjust each steel spike (403) sequentially to align with the reserved opening, ensuring that the end of the steel spike (403) is limited to the wall thickness of the reserved tube body protrusion opening (102) on the side wall.

[0058] 6. The outer shell structure (1) of the pile body is disassembled into sections and then welded to the locking stiffening plate structure (3), the umbrella-shaped bone spur extension structure (4), the fixed locking plate structure (5), and the head stiffening plate (6) in sequence to form an integral steel pipe pile.

[0059] 7. Weld the closed thin steel sheet (103) to the outside of the reserved pipe body protrusion hole (102) to form a closed steel pipe pile shell.

[0060] 8. Inspect verticality and flatness.

[0061] Step 3: Transportation and on-site storage of pile foundations.

[0062] The prefabricated steel pipe piles with spurs are transported to the construction site. During transportation, a special transport frame is used to secure the piles and prevent deformation or damage. Upon arrival at the site, the piles are stored in a designated area, supported by wooden blocks to prevent direct contact with the ground.

[0063] Step 4: Pile Foundation Positioning Based on the designed pile positions, the site is leveled and surveyed, the center point of the pile position is marked, and the coordinates and elevation of the pile position are checked to ensure that the pile position deviation is controlled within the design allowable range.

[0064] Step 5: Pile driving construction 1. Prepare static pile driving equipment according to the pile driving process requirements, check the equipment operation status, and verify whether the pile driving force meets the design requirements.

[0065] 2. Static driving piles are used to drive the spiky steel pipe piles to the design elevation. The static driving pile process applies continuous pressure to the pile head using hydraulic jacks, causing the pile to gradually sink into the soil.

[0066] 3. During the pile driving process, the bone spike locking mechanism is located inside the pile body. The closed thin steel sheet (103) seals the reserved tube body protrusion hole (102) to prevent soil, mud, and impurities from entering the pile body and ensure a clean operating environment for the bone spike expansion mechanism. The steel strand group is fixed inside the pile body by the line group anti-fall clip (203) to prevent the steel strand from falling due to vibration or impact during the pile driving process.

[0067] 4. After driving the pile to the design elevation, stop pile driving or hammering operations, measure the elevation of the pile top and the verticality of the pile body, and confirm that the pile driving quality is qualified. After the pile driving is completed, the pile body of the spiky steel pipe pile forms initial contact with the surrounding soil. At this time, the pile side friction and pile end resistance have been formed, but the spiky parts have not yet extended. The effective cross section of the pile body is the circular cross section corresponding to the outer diameter of the spiky steel pipe pile.

[0068] Step 6: Steel strand lifting and bone spur expansion construction (see...) Figure 2 , Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 ) 1. After the pile driving is completed, manually pull out the upper steel strand (201) of the fixed locking plate structure (5) from the middle opening of the head stiffening plate (6).

[0069] 2. Install a through-type tension jack (7) at the pile head. The jack base is supported on a circular bearing steel plate (601). A limiter is set on the pile top to restrict the plane position of the jack and prevent the jack from slipping.

[0070] 3. Pass the steel strand (201) through the through-type tensioning jack (7), taut it vertically, and let the tensioning jack fix and clamp the steel strand (201), and record the initial position.

[0071] 4. Using the CNC lifting system, start the tensioning jacks to lift the steel strands (201) in stages. The tension force is transmitted through the steel strands to the lifting clamps (202), which then transmit the tension force to the four sets of umbrella-shaped spur extension structures (4), driving them to move upward. Start the tensioning lifting jacks to apply the preset tension force to the steel strands. The tensioning construction adopts a staged loading and step-by-step holding method, generally divided into four to five stages. The first stage of tensioning eliminates the initial slack of the steel strands, allowing the components to make initial contact.

[0072] During the second stage of tensioning, the spikes begin to extend outwards, and the ends of the steel teeth break through the thin steel sheet closure and emerge from the tube opening. During the third stage of tensioning, the spikes continue to extend outwards, and the ends of the spikes embed into the surrounding soil, forming a preliminary mechanical engagement. During the fourth or fifth stage of tensioning to the design value, the spikes extend to the preset position, and the locking head contacts and engages with the locking buckle flange, forming a rigid constraint. During the load-bearing period, the jack stroke and hydraulic pressure changes are monitored; stable stroke indicates that the locking mechanism has been locked.

[0073] 5. As the four sets of umbrella-shaped bone spur expansion structures (4) are lifted upwards simultaneously, the through steel pipe (401) and the bone spur positioning ring (406) are also lifted upwards simultaneously, causing the steel bone spur (403) to extend outwards towards the opening, piercing the closed thin steel sheet (103) and splitting into the soil around the pile. As the steel bone spur (403) expands outwards, the T-shaped joint at the end gradually retreats along the top arc surface of the limiting positive row of locking teeth (404) and then sinks into the locking tooth groove. As the steel strand (201) drives the through steel pipe (401) to be lifted, the locking buckle (402) is finally lifted and locked into the inner ring opening of the circular single-layer stiffening plate (301). At this time, the bone spur support rod (407) is locked in the groove of the limiting positive row of locking teeth (404). At this time, the steel bone spur (403) and the bone spur support rod (407) form a stable triangular support structure. The construction principle of the remaining umbrella-shaped bone spur extension structures (4) is the same as the above method.

[0074] 6. Improve the criteria for determining termination: ① The final judgment scheme is that the length of the steel strand lifting should be equal to the distance A = 40cm between the locking buckle (402) and the locking stiffening plate structure (3) during pile manufacturing.

[0075] ② The CNC lifting system shows a sudden increase in lifting force (the lifting force suddenly increases after the cable dies).

[0076] ③ The CNC lifting system displays a sudden change in lifting displacement to 0 (the lifting displacement changes suddenly after the cable dies).

[0077] 7. Terminate the lifting, remove the jack, and put the excess steel strand (201) back through the opening in the middle of the head stiffening plate (6), and secure it by placing it on the fixed locking plate structure (5).

[0078] 8. Seal the opening of the circular single-layer stiffening plate (601) with a sealing plate (604).

[0079] Step 7: Pile Foundation Bearing Capacity Testing and Acceptance According to the specifications, the vertical bearing capacity static load test was carried out on the precast steel pipe piles with fixed umbrella-shaped spurs that had been constructed. After the requirements were met, the next step of construction was carried out.

[0080] Step 8: Construction of pile head anchorage reinforcement (see...) Figure 3 ) The steel bar sleeve (8) is arranged in a circumferential row along the center of the head stiffening plate (6) and welded to the top of the head stiffening plate (6). The steel bar (9) is then connected to the steel bar sleeve (8) by a threaded connection to ensure the anchorage length between the pile and the upper foundation, forming a whole and transmitting tensile force.

[0081] Step 9: Construction of structural components above the pile head The pile cap or base slab concrete is poured on the top of the pile, and the reliable connection between the pile foundation and the superstructure is achieved through the steel sleeve (8) and the connecting steel bar (9).

[0082] (2) Example 2: This example uses a non-tower area basement anti-buoyancy project as a case study. The project is located in a soft plastic clay area, with the highest groundwater level found to be 2m below the ground surface. The basement has four floors, and the foundation elevation is 13m below ground. The structure's own weight cannot meet the anti-buoyancy requirements, so additional anti-buoyancy measures are needed to ensure the structure's anti-buoyancy safety.

[0083] Step 1: Pile Foundation Design 1. According to the engineering geological survey report, the standard value of the ultimate lateral resistance of soft plastic clay is qsik = 38 kPa. The buoyancy force per square meter after deducting its own weight is 80 kN.

[0084] In the early stages, we compared and selected either Option 1 - anti-buoyancy anchor bolts or Option 2 - anti-buoyancy steel pipe piles with bone spurs.

[0085] Option 1: Select a 0.3m diameter anti-buoyancy anchor bolt, 10m long. Pull-out bearing capacity: =0.7 x 38 x 3.14 x 0.3 x 10 = 250 kN Option 2: Select 0.3m diameter spur steel pipe piles. After the spurs expand, the effective pull-out pile diameter is 0.5m and the pile length is 10m.

[0086] Pull-out bearing capacity: = x0.7x38x3.14x0.3x10=333kN; The effective pile diameter reduction factor is set to 0.5.

[0087] In summary, Option 1 – the anti-buoyancy anchor – is unsuitable due to difficulties in drilling in soft plastic clay, the need for underwater operation, and its low bearing capacity. Option 2 – the spiky steel pipe pile – offers simpler drilling and improved bearing capacity. Option 2 was ultimately selected.

[0088] 2. According to the vertical load requirements of the pile, the diameter of the bone-spur steel pipe pile is 30cm, the wall thickness is 1cm, and the steel type is Q355.

[0089] 3. Due to the presence of bone spurs, the tensile strength increases by 73kN. Two sets of bone spurs are installed, each with eight steel spurs. One set is placed 1m from the pile tip, and subsequent sets are placed every 4 meters, for a total of 16 spurs. Each spur bears a vertically increased load of 4.6kN. Using triangular member bending and compressive strength calculations, the spurs are selected to be 20cm long with a 2cm flat top, made of Q355 steel. The lower part and protruding ends are fitted with blade edges. The distance A between the locking buckle and the locking stiffening plate in the umbrella-shaped bone spur extension structure is 17.3cm. The angle between the spur and the vertical line inside the pile is 30 degrees, and the steel is Q355. After extension, the spurs are perpendicular to the pile length, protruding 0.1m from the outer wall of the pile. Two sets of eight steel spurs are installed, one set 1m from the pile tip, and subsequent sets are placed every 4 meters, for a total of two sets. The strut has a cross-section width of 1cm, a height of 2cm, and a length of 16cm, made of Q355 steel. The remaining locking stiffening plate structure, fixed locking disc structure, and end cap stiffening plate components are all made of 1cm thick Q355 steel plate. The steel strand used is 1×7-9.5-1860, with a maximum lifting force of 101kN.

[0090] Step 2: Pile Construction and Inspection (See also) Figure 1 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 16 , Figure 17 ) 1. According to the design requirements, the following components are processed and manufactured in the factory: pile body shell structure (1), lifting cable system (2), locking stiffening plate structure (3), umbrella-shaped spur extension structure (4), fixed locking disc structure (5), and end cap stiffening plate (6). Each component is treated with rust and corrosion prevention.

[0091] 2. Set up a vertical support frame and arrange the two sets of locking stiffening plate structures (3), the two sets of umbrella-shaped spur extension structures (4), and the fixed locking plate structure (5) from bottom to top according to the design vertical elevation in the order of umbrella-shaped spur extension structure 1 - locking stiffening plate structure 1 - umbrella-shaped spur extension structure 2 - locking stiffening plate structure 2 - fixed locking plate structure.

[0092] 3. Install and fix the anti-fall clamp (203) on the steel strand (201) in the lifting cable system (2), then pass the lower steel strand of the anti-fall clamp (203) through the middle holes of the two sets of locking stiffening plate structures (3) and umbrella-shaped rib extension structures (4) in sequence, and finally install and fix the lifting clamp (202) on the lower part of each set of umbrella-shaped rib extension structures (4) to support the umbrella-shaped rib extension structure. Structure (4). Repeat the above operation according to the number of locking stiffening plate structures (3) and umbrella-shaped bone spur extension structures (4) set.

[0093] 4. Measure the distance between the locking buckle (402) and the locking stiffening plate structure (3) in the umbrella-shaped spur extension structure (4) to ensure that the distance between each adjacent component is consistent. If they are inconsistent, readjust the position of the lifting clamp (202) to ensure that the distance is consistent, and record the final distance value A=17.3cm.

[0094] 5. Adjust each steel spike (403) sequentially to align with the reserved opening, ensuring that the end of the steel spike (403) is limited to the wall thickness of the reserved tube body protrusion opening (102) on the side wall.

[0095] 6. The outer shell structure (1) of the pile body is disassembled into sections and then welded to the locking stiffening plate structure (3), the umbrella-shaped bone spur extension structure (4), the fixed locking plate structure (5), and the head stiffening plate (6) in sequence to form an integral steel pipe pile.

[0096] 7. Weld the closed thin steel sheet (103) to the outside of the reserved pipe body protrusion hole (102) to form a closed steel pipe pile shell.

[0097] 8. Inspect verticality and flatness.

[0098] Step 3: Transportation and on-site storage of pile foundations.

[0099] The prefabricated steel pipe piles with spurs are transported to the construction site. During transportation, a special transport frame is used to secure the piles and prevent deformation or damage. Upon arrival at the site, the piles are stored in a designated area, supported by wooden blocks to prevent direct contact with the ground.

[0100] Step 4: Pile Foundation Positioning Based on the designed pile positions, the site is leveled and surveyed, the center point of the pile position is marked, and the coordinates and elevation of the pile position are checked to ensure that the pile position deviation is controlled within the design allowable range.

[0101] Step 5: Pile driving construction 1. Prepare static pile driving equipment according to the pile driving process requirements, check the equipment operation status, and verify whether the pile driving force meets the design requirements.

[0102] 2. Static driving piles are used to drive the spiky steel pipe piles to the design elevation. The static driving pile process applies continuous pressure to the pile head using hydraulic jacks, causing the pile to gradually sink into the soil.

[0103] 3. During the pile driving process, the bone spike locking mechanism is located inside the pile body. The closed thin steel sheet (103) seals the reserved tube body protrusion hole (102) to prevent soil, mud, and impurities from entering the pile body and ensure a clean operating environment for the bone spike expansion mechanism. The steel strand group is fixed inside the pile body by the line group anti-fall clip (203) to prevent the steel strand from falling due to vibration or impact during the pile driving process.

[0104] 4. After driving the pile to the design elevation, stop pile driving or hammering operations, measure the elevation of the pile top and the verticality of the pile body, and confirm that the pile driving quality is qualified. After the pile driving is completed, the pile body of the spiky steel pipe pile forms initial contact with the surrounding soil. At this time, the pile side friction and pile end resistance have been formed, but the spiky parts have not yet extended. The effective cross section of the pile body is the circular cross section corresponding to the outer diameter of the spiky steel pipe pile.

[0105] Step 6: Steel strand lifting and bone spur expansion construction (see...) Figure 2 , Figure 9 , Figure 10 , Figure 11 , Figure 12 , Figure 13 ) 1. After the pile driving is completed, manually pull out the upper steel strand (201) of the fixed locking plate structure (5) from the middle opening of the head stiffening plate (6).

[0106] 2. Install a through-type tensioning jack (7) at the pile head. The jack base is supported on a circular bearing steel plate (601). A limiter is installed on the top of the pile to restrict the plane position of the jack and prevent it from slipping.

[0107] 3. Pass the steel strand (201) through the through-type tensioning jack (7), taut it vertically, and let the tensioning jack fix and clamp the steel strand (201), and record the initial position.

[0108] 4. Using the CNC lifting system, start the tensioning jack to lift the steel strand (201) in stages. The tension force is transmitted through the steel strand to the lifting clamp (202), which then transmits the tension force to the two sets of umbrella-shaped spur extension structures (4), driving them to move upward. Start the tensioning lifting jack to apply the preset tension force to the steel strand. The tensioning construction adopts a staged loading and step-by-step holding method, generally divided into four to five stages. The first stage of tensioning eliminates the initial slack of the steel strand, allowing the components to make initial contact. During the second stage of tensioning, the spurs begin to extend outward, and the ends of the steel teeth break through the thin steel sheet closure and pass through the tube opening. During the third stage of tensioning, the spurs continue to extend outward, and the ends of the spurs embed into the surrounding soil, forming a preliminary mechanical interlock. During the fourth or fifth stage of tensioning, the spurs extend to the preset position, and the locking head contacts and embeds into the locking buckle, forming a rigid constraint. During the load period, monitor the jack stroke and oil pressure changes. Stable stroke indicates that the locking mechanism has been locked.

[0109] 5. As the two sets of umbrella-shaped bone spur expansion structures (4) are lifted upwards in sync, the through steel pipe (401) and the bone spur positioning ring (406) are also lifted upwards in sync, driving the steel bone spur (403) to extend outwards towards the opening, piercing the closed thin steel sheet (103), splitting and piercing into the soil around the pile. As the steel bone spur (403) expands outwards, the end T-shaped joint of the bone spur strut (407) gradually retreats along the top arc surface of the limiting positive row of locking teeth (404) and then sinks into the locking tooth groove. As the steel strand (201) drives the through steel pipe (401) to be lifted, the locking buckle (402) is finally lifted and locked into the inner ring opening of the circular single-layer stiffening plate (301). At this time, the bone spur strut (407) is locked in the groove of the limiting positive row of locking teeth (404). At this time, the steel bone spur (403) and the bone spur strut (407) form a stable triangular support structure. The construction principle of the remaining umbrella-shaped bone spur extension structures (4) is the same as the above method.

[0110] 6. Improve the criteria for determining termination: ①The final judgment scheme is that the length of the steel strand lifting should be equal to the distance A = 17.3cm between the locking buckle (402) and the locking stiffening plate structure (3) during pile manufacturing.

[0111] ② The CNC lifting system shows a sudden increase in lifting force (the lifting force suddenly increases after the cable dies).

[0112] ③ The CNC lifting system displays a sudden change in lifting displacement to 0 (the lifting displacement changes suddenly after the cable dies).

[0113] 7. Terminate the lifting, remove the jack, and put the excess steel strand (201) back through the opening in the middle of the head stiffening plate (6), and secure it by placing it on the fixed locking plate structure (5).

[0114] 8. Seal the opening of the circular single-layer stiffening plate (601) with a sealing plate (604).

[0115] Step 7: Pile Foundation Bearing Capacity Testing and Acceptance According to the specifications, the pull-out bearing capacity of the precast steel pipe piles with fixed umbrella-shaped spurs that have been constructed should be tested. After the requirements are met, the next step of construction can be carried out.

[0116] Step 8: Construction of pile head anchorage reinforcement (see...) Figure 3 ) The steel bar sleeve (8) is arranged in a circumferential row along the center of the head stiffening plate (6) and welded to the top of the head stiffening plate (6). The steel bar (9) is then connected to the steel bar sleeve (8) by a threaded connection to ensure the anchorage length between the pile and the upper foundation, forming a whole and transmitting tensile force.

[0117] Step 9: Construction of structural components above the pile head The pile cap or base slab concrete is poured on the top of the pile, and the reliable connection between the pile foundation and the superstructure is achieved through the steel sleeve (8) and the connecting steel bar (9).

[0118] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cable-stayed umbrella-shaped spur precast steel pipe pile, wherein the spur steel pipe pile is precast in a factory as a single unit, characterized in that: The device consists of: a pile shell structure (1), a lifting cable system (2), a locking stiffening plate structure (3), an umbrella-shaped spur extension structure (4), a fixed locking disc structure (5), and a head stiffening plate (6). The steel strands (201) in the lifting cable system (2) pass through the holes in the middle of the locking stiffening plate structure (3) and the umbrella-shaped spur extension structure (4). The lifting clamp (202) limits and supports the umbrella-shaped spur extension structure (4). The anti-fall clamp (203) holds the top of the steel pipe stiffening ring (303) of the uppermost locking stiffening plate structure (3) to prevent it from falling and achieve positioning. The steel strands (201) above the anti-fall clamp (203) are clamped on the fixed locking disc structure (5) to ensure operating space for later lifting. Finally, the locking stiffening plate structure (3), the umbrella-shaped spur extension structure (4), the fixed locking disc structure (5), and the head stiffening plate (6) are welded to the pile shell structure (1) to form an integral steel pipe pile.

2. The cable-stayed umbrella-shaped spur precast steel pipe pile according to claim 1, characterized in that; The outer shell structure (1) of the pile body is composed as follows: a circular steel pipe (101) is welded to a conical pile tip (104) as a whole; a circular steel pipe (101) has a pre-reserved pipe body protrusion hole (102) on its side wall; and a closed thin steel sheet (103) is welded to the outside of the pre-reserved pipe body protrusion hole (102) to form a closed steel pipe pile shell.

3. The cable-stayed umbrella-shaped spur precast steel pipe pile according to claim 1, characterized in that; The lifting cable system (2) consists of steel strands (201), lifting clamps (202), and anti-fall clamps (203). Each lifting clamp (202) is fixed on the steel strands (201) and placed at the bottom of each umbrella-shaped spur extension structure (4). The anti-fall clamps (203) are fixed on the steel strands (201) and placed at the top of the top locking stiffening plate structure (3). The spacing between the lifting clamps (202) is the same as the spacing between the locking stiffening plate structures (3).

4. The cable-stayed umbrella-shaped spur precast steel pipe pile according to claim 1, characterized in that; The locking stiffening plate structure (3) consists of a circular single-layer stiffening plate (301), a rectangular stiffening plate (302), a steel pipe stiffening ring (303), and a strut positioning double lug (304). The spacing between each locking stiffening plate structure (3) is ≥ 5 times the pile diameter. The circular single-layer stiffening plate (301) is welded to the inner side of the pile shell structure (1) and is perpendicular to the pile shell. The diameter of the steel pipe stiffening ring (303) is larger than the inner ring diameter of the circular single-layer stiffening plate (301). Welded to the upper part of the circular single-layer stiffening plate (301), the rectangular stiffening plate (302) is distributed in a regular row along the circumferential direction with the center of the circular single-layer stiffening plate (301) as the base point, and is welded and fixed to the top surface of the circular single-layer stiffening plate (301), the side of the steel pipe stiffening ring (303), and the inner side of the pile shell structure (1); the double ear pieces (304) of the strut positioning are arranged in a regular row along the center of the circular single-layer stiffening plate (301) and welded to the edge of the inner ring opening at the bottom of the circular single-layer stiffening plate (301).

5. The cable-stayed umbrella-shaped spur precast steel pipe pile according to claim 1, characterized in that; The umbrella-shaped bone spur extension structure (4) consists of a through-hole steel pipe (401), a locking buckle (402), a steel bone spur (403), a limiting aligned locking tooth (404), a support rod limiting steel bar (405), a bone spur positioning ring (406), and a bone spur support rod (407); the locking buckle (402) is arranged in a straight line along the center of the through-hole steel pipe (401) and welded to the top thickness surface of the through-hole steel pipe (401); the bone spur positioning ring (406) is welded and positioned to the lower side wall of the through-hole steel pipe (401); the top surface of the protruding end of the steel bone spur (403) is flat, and the tip faces outward and downward; the top surface of the middle standard section is flat. The tip faces downwards; the root is a ring, which is limited to the bone spur positioning ring (406) to ensure that the root can rotate; the limiting positive row of locking teeth (404) is welded to fix the top plane of the steel bone spur (403); the length of the two support rod limiting steel bars (405) is greater than the length of the limiting positive row of locking teeth (404), and they are welded parallel to the top plane of the steel bone spur (403), with a gap between the steel bars; one end of the bone spur support rod (407) is looped to the support rod positioning double ear (304) to ensure that the root can rotate, and the other end is a T-shaped connector that passes through the gap and is limited between the two support rod limiting steel bars (405) and the limiting positive row of locking teeth (404).

6. The cable-stayed umbrella-shaped spur precast steel pipe pile according to claim 1, characterized in that; The fixed locking disc structure (5) consists of a circular single-layer steel plate (501) and a circular steel strand lead-out outlet clamp (502). The circular steel strand lead-out outlet clamp (502) is welded to the circular single-layer steel plate (501). The steel strand (201) can pass through the hole in the middle of the circular single-layer steel plate (501) and be led out along the lead-out outlet of the circular steel strand lead-out outlet clamp (502), and clamped in the lead-out outlet clamp bar. The remaining length of the steel strand (201) can be coiled on the circular single-layer steel plate (501).

7. The cable-stayed umbrella-shaped spur precast steel pipe pile according to claim 1, characterized in that; The head stiffening plate (6) is composed of a circular single-layer stiffening plate (601), a rectangular stiffening plate (602), a steel pipe stiffening ring (603), and a sealing plate (604); the circular single-layer stiffening plate (601) is welded to the inner top of the pile shell structure (1) and is perpendicular to the pile shell; the diameter of the steel pipe stiffening ring (603) is equal to the inner ring diameter of the circular single-layer stiffening plate (601), and the steel pipe stiffening ring (603) is welded to the circular single-layer stiffening plate (601). At the bottom of the single-layer stiffening plate (601), rectangular stiffening plates (602) are distributed in a regular row along the circumferential direction with the center of the circular single-layer stiffening plate (601) as the base point, and are respectively welded and fixed to the bottom surface of the circular single-layer stiffening plate (601), the side of the steel pipe stiffening ring (603), and the inner side of the pile shell structure (1); after the cable is lifted into place and before the pile top cap is poured, the opening of the circular single-layer stiffening plate (601) is welded and sealed by the sealing plate (604).

8. The cable-stayed umbrella-shaped spur precast steel pipe pile according to claim 1, characterized in that; The steel bar sleeve (8) is arranged in a circumferential row along the center of the head stiffening plate (6) and welded to the top of the head stiffening plate (6).

9. The cable-stayed umbrella-shaped spur precast steel pipe pile according to claim 1, characterized in that; The steel bar (9) is connected to the steel bar sleeve (8) by a threaded connection to ensure the anchorage length of the pile and the upper foundation, forming a whole and transmitting tensile force.

10. A construction method for precast steel pipe piles with cable-stayed umbrella-shaped spurs, characterized in that, The specific steps are as follows: Step 1: Pile Foundation Design Determine the pile diameter, wall thickness, pile length, and spur arrangement scheme for the spur steel pipe pile; the spur arrangement scheme includes the number of spurs, the distribution position of the spurs along the height direction of the pile body, the extension length of the spurs, and the angle parameters between the spurs and the axis of the pile body. Step 2: Pile Construction and Inspection (1) Fabrication of pile body shell structure (1), lifting cable system (2), locking stiffening plate structure (3), umbrella-shaped bone spur extension structure (4), fixing locking plate structure (5), end cap stiffening plate (6); (2) Set up a vertical support frame and place the locking stiffening plate structure (3), umbrella-shaped bone spur extension structure (4), and fixed locking plate structure (5) in layers according to the designed vertical elevation; (3) Install and fix the anti-fall clamp (203) on the steel strand (201) in the lifting cable system (2), then pass the lower steel strand of the anti-fall clamp (203) through the middle hole of the locking stiffening plate structure (3) and the umbrella-shaped bone spur extension structure (4) in sequence, and finally install and fix the lifting clamp (202) on the lower part of the umbrella-shaped bone spur extension structure (4) to support the umbrella-shaped bone spur extension structure (4); repeat the above operation according to the number of locking stiffening plate structures (3) and umbrella-shaped bone spur extension structures (4) set; (4) Measure the distance between the locking buckle (402) and the locking stiffening plate structure (3) in the umbrella-shaped bone spur extension structure (4) to ensure that the distance between each adjacent component is consistent; if they are inconsistent, adjust the position of the lifting clamp (202) again to ensure that the distance is consistent, and record the final distance value A. (5) Adjust each steel spike (403) sequentially to align with the reserved opening, ensuring that the end of the steel spike (403) is limited to the wall thickness of the reserved tube body protruding from the side wall (102); (6) The outer shell structure (1) of the pile body is disassembled into sections and then welded to the locking stiffening plate structure (3), the umbrella-shaped bone spur extension structure (4), the fixed locking plate structure (5), and the head stiffening plate (6) in sequence to form an integral steel pipe pile; (7) Weld the closed thin steel sheet (103) to the outside of the reserved pipe body protrusion hole (102) to form a closed steel pipe pile shell; (8) Inspect verticality and flatness; Step 3: Transportation and on-site storage of pile foundations The prefabricated bone-spur steel pipe piles are transported to the construction site. During transportation, a special transport frame is used to fix the pile body to prevent deformation or damage. After arriving at the site, the piles are stored in a designated area with wooden supports to prevent the pile body from directly contacting the ground. Step 4: Pile Foundation Positioning Based on the designed pile positions, the site is leveled and surveyed, the center point of the pile position is marked, and the coordinates and elevation of the pile position are checked to ensure that the pile position deviation is controlled within the design allowable range. Step 5: Pile driving construction (1) Prepare static pile driving equipment or hammer pile driving equipment according to the pile driving process requirements, check the equipment operation status, and verify whether the pile driving force or hammer energy meets the design requirements. (2) The steel pipe piles with bone spurs are driven to the design elevation by static pile driving or hammer driving. Static pile driving uses hydraulic jacks to apply continuous pressure to the pile head, so that the pile body gradually sinks into the soil. Hammer driving uses an impact hammer to apply impact force to the pile head, so that the pile body sinks into the soil under the action of impact force. (3) During the pile driving process, the bone spike locking mechanism is located inside the pile body. The closed thin steel sheet (103) closes the reserved tube body protrusion hole (102) to prevent soil, mud and impurities from entering the pile body and ensure that the bone spike expansion mechanism operates in a clean environment. The steel strand group is fixed inside the pile body by the line group anti-fall clip (203) to prevent the steel strand from falling due to vibration or impact during the pile driving process. (4) After the pile is driven to the design elevation, stop the pile driving or hammering operation, measure the pile top elevation and the verticality of the pile body, and confirm that the pile driving quality is qualified. After the pile is driven, the pile body of the spur steel pipe pile forms initial contact with the surrounding soil. At this time, the pile side friction and pile end resistance have been formed, but the spurs have not yet extended. The effective section of the pile body is the circular section corresponding to the outer diameter of the spur steel pipe pile. Step 6: Steel strand lifting and bone spur expansion construction (1) After the pile driving is completed, manually pull out the upper steel strand (201) of the fixed locking plate structure (5) from the middle opening of the head stiffening plate (6); (2) Install a through-type tension jack (7) at the pile head position; the jack base is supported on a circular bearing steel plate (601), and a limiter is set on the pile top to limit the plane position of the jack and prevent the jack from slipping; (3) Pass the steel strand (201) through the through-type tensioning jack (7), straighten it vertically, and let the tensioning jack fix and clamp the steel strand (201), and record the initial position; (4) The tension jack is started using the CNC lifting system to lift the steel strand (201). The tension force is transmitted to the lifting clamp (202) through the steel strand. The lifting clamp (202) transmits the tension force to the umbrella-shaped bone spur extension structure (4) and drives it to move upward. (5) As the umbrella-shaped bone spur expansion structure (4) rises upward, the through steel pipe (401) and the bone spur positioning ring (406) also rise upward in sync, driving the steel bone spur (403) to extend outward toward the opening, piercing the closed thin steel sheet (103), splitting and piercing into the soil around the pile; as the bone spur support rod (407) expands outward along the steel bone spur (403), the end T-shaped joint gradually retreats along the top arc surface of the limiting positive row of locking teeth (404) and then sinks into the locking. Inside the toothed groove, as the steel strand (201) drives the through steel pipe (401) to rise, the locking buckle (402) is finally lifted and locked into the inner ring hole of the circular single-layer stiffening plate (301). At this time, the bone spur support rod (407) is locked in the groove of the limiting positive row of locking teeth (404). At this time, the steel bone spur (403) and the bone spur support rod (407) form a stable triangular support structure; the construction principle of the remaining umbrella-shaped bone spur extension structure (4) is the same as the above method. (6) Raise the criteria for determining termination: ① The final judgment scheme is that the length of the steel strand lifting should be equal to the distance A between the locking buckle (402) and the locking stiffening plate structure (3) during pile fabrication; ② The CNC lifting system displays a sudden increase in lifting force; ③ The CNC lifting system displays a sudden change in lifting displacement to 0; (7) Terminate the lifting, remove the jack, and put the excess steel strand (201) back from the opening in the middle of the head stiffening plate (6), and secure it to the fixed locking plate structure (5). (8) Seal the opening of the annular single-layer stiffening plate (601) by welding with a sealing plate (604); Step 7: Pile Foundation Bearing Capacity Testing and Acceptance According to the specifications, the vertical bearing capacity and tensile bearing capacity of the precast steel pipe piles with cable-stayed umbrella-shaped spurs that have been constructed were tested. Step 8: Construction of pile head anchorage reinforcement The steel sleeve (8) is arranged in a circumferential row along the center of the head stiffening plate (6) and welded to the top of the head stiffening plate (6). The steel bar (9) is then connected to the steel sleeve (8) by a threaded connection to ensure the anchorage length between the pile and the upper foundation, forming a whole and transmitting tensile force. Step 9: Construction of structural components above the pile head The pile cap or base slab concrete is poured on the top of the pile, and the reliable connection between the pile foundation and the superstructure is achieved through the steel sleeve (8) and the connecting steel bar (9).

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