Anti-floating steel pipe pile structure of existing underground structure driven by lead screw motor to unfold anchor flukes and construction method

Abstract

The invention discloses a lead screw motor driven unfolding anchor fluke anti-floating steel pipe pile structure of an existing underground structure and a construction method. The lead screw motor driven unfolding anchor fluke anti-floating steel pipe pile structure comprises a steel pipe pile body, a lead screw motor driving device, a pushing transmission assembly and an anchor fluke structure. The end of the steel pipe pile body is open, and the steel pipe pile body is suitable for construction of a low-clearance small equipment anchor rod static pressure pile machine. 4-6 anchoring steel bars are welded at the top of the steel pipe pile main body, are uniformly distributed along the steel pipe pile and are anchored on an underground structure bottom plate. During implementation, the space adaptability is extremely high, a low-clearance anchor rod static pressure pile machine is adopted for construction in the whole process, a core device is compact in size and completely adapts to the construction environment with the limited clearance of an existing underground structure, and the problem that conventional high and large equipment cannot conduct construction is solved; due to the design that the screw motor pushes and drives the anchor flukes to be unfolded, force transmission is direct, unfolding force is large, after the anchor flukes are embedded into a soil body, a dual-uplift mechanism is formed, the uplift bearing capacity is remarkably improved compared with a traditional steel pipe pile, and the high anti-floating requirement can be met.

Description

Technical Field

[0001] This invention relates to the field of anti-buoyancy reinforcement engineering technology for existing underground structures, specifically to the anti-buoyancy steel pipe pile structure and construction method of existing underground structures with screw motor driven deployment of anchor claws. Background Technology

[0002] With the full implementation of the South-to-North Water Diversion Project and the policy of reducing groundwater extraction, as well as the increase in extreme and continuous rainfall across the country, groundwater levels have been rising continuously in many regions of both the north and south. A large number of existing underground structures (such as underground parking garages, underground rail transit projects, and power projects) are facing the risk of floating and damage due to rising groundwater levels, exceeding their original design buoyancy resistance and affecting structural safety and normal use.

[0003] As a core technical means to solve the problem of buoyancy in underground structures, anti-buoyancy piles resist the buoyancy of groundwater through the side friction between the pile body and the soil and the end bearing capacity of the bearing layer at the bottom of the pile, thus ensuring structural stability.

[0004] For buoyancy reinforcement of existing structures, anti-buoyancy piles have significant advantages in providing strong and stable pull-out resistance. However, the limited clearance of existing underground structures severely restricts the selection of construction machinery. For example, conventional bored piles require tall equipment, and the existing space is often insufficient to meet the construction requirements. Therefore, the buoyancy reinforcement of existing structures should prioritize anti-buoyancy piles that are suitable for low clearance, require small equipment, and cause minimal disturbance to the structure and surrounding environment.

[0005] Among existing anti-buoyancy reinforcement technologies, anchored static pressure steel pipe piles have become the preferred type for anti-buoyancy reinforcement of existing underground structures due to their short single-section pile length, low equipment height requirements, low construction vibration, and low noise. However, they still have many shortcomings: On the one hand, the pull-out bearing capacity of traditional steel pipe piles mainly relies on the side friction resistance between the pile body and the soil, which is difficult to meet the requirements in soft strata or high anti-buoyancy scenarios. If the bearing capacity is improved by expanding the base or adding anchor bars, it will increase the complexity and cost of construction. On the other hand, the existing anti-buoyancy piles with anchoring structures mostly have anchoring drive devices that are disposable or cumbersome to disassemble and cannot be reused, resulting in waste of engineering materials and low construction efficiency. In addition, some anchoring structures have complex designs, high processing precision requirements, and are difficult to install on site, further restricting the construction progress and project quality.

[0006] Therefore, developing an anti-buoyancy steel pipe pile suitable for existing underground structures with limited clearance, featuring convenient construction, stable and reliable tensile bearing capacity, reusable drive and connection devices, and easy processing and installation of the anchoring structure, has significant engineering needs and technical value. Based on this, this invention provides an anti-buoyancy steel pipe pile structure with screw motor-driven deployment of anchor claws, its construction, and construction method. Summary of the Invention

[0007] This invention aims to address the technical pain points in existing underground structure anti-buoyancy reinforcement projects, such as insufficient pull-out bearing capacity of conventional steel pipe piles, non-reusable anchoring drive devices, and complex fabrication and installation of anchoring structures. Specifically, it achieves the following objectives through an anti-buoyancy steel pipe pile structure composed of a steel pipe pile body, a screw motor drive device, a jacking transmission assembly, and an anchor claw structure, combined with a corresponding construction process: adapting to construction environments with limited clearance in existing underground structures, eliminating the need for large construction equipment, facilitating the construction process, and minimizing disturbance to the existing structure and surrounding environment; and using a screw motor-driven jacking transmission assembly to extend the anchor claw structure outwards. It is embedded in the surrounding soil, forming a dual pull-out resistance mechanism of "pile side friction resistance + anchor claw anchoring force", which significantly improves the pull-out bearing capacity of the steel pipe pile to meet the high anti-buoyancy requirements; the screw motor drive device and related connecting devices are easy to disassemble and do not need to be solidified with the pile body. They can be quickly transferred to the construction of the next steel pipe pile for reuse, effectively reducing project costs and improving construction efficiency; the anchor claw structure adopts a hinged connecting rod design, which is simple in components, easy to process, and convenient to install on site, ensuring construction quality and progress. It is suitable for anti-buoyancy reinforcement projects of various existing underground structures such as underground garages and underground rail transit projects.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] The existing underground structure includes a screw motor driven deployment anchor claw anti-buoyancy steel pipe pile structure and construction method, including the steel pipe pile body, screw motor drive device, jacking transmission assembly, and anchor claw structure.

[0010] The main body of the steel pipe pile has an open end, which is suitable for construction by a low-headroom, small-equipment anchor static pressure pile driver; 4 to 6 anchoring steel bars are welded to the top of the main body of the steel pipe pile, which are evenly distributed along the steel pipe pile and anchored to the bottom plate of the underground structure, with an anchoring length of not less than 39d (d is the inner diameter of the main body of the steel pipe pile); the length of a single section of the push rod is consistent with that of the main body of the steel pipe pile, and the connection of each section of the main body of the steel pipe pile is made by angle steel bevel welding, and the push rod is welded;

[0011] The lead screw motor drive device includes a motor body, a motor cable, a lead screw, and a ball nut;

[0012] The jacking transmission assembly consists of a lead screw and jacking rod connector and a jacking rod. The end of the jacking rod is tapered to form a guide head, which facilitates cutting into the soil layer. The lead screw and jacking rod connector consists of three pads with different hole diameters: pad one, pad two, and pad three, locking nuts, and a lead screw drive device and jacking rod connecting rod 44. The hole diameter of pad one is larger than the diameter of the lead screw, the hole diameter of pad two is larger than the outer diameter of the ball nut, and the hole diameter of pad three is equal to the diameter of the jacking rod. Clamping plates form clamping anchor plates.

[0013] The anchor claw structure is a five-claw symmetrical structure, including a pin lug plate welded to the main wall of the steel pipe pile, a five-hole pin seat connected to the push rod, a connecting rod one, and a connecting rod two; the five-hole pin seat and the push rod are clamped by the anchor claw structure clamping plates; all the anchor claw structure clamping plates are open structures; the anchor claws are deployed by the push drive of the motor body.

[0014] Preferably, the anchoring steel bars of the main body of the steel pipe pile are ultimately anchored into the underground structure bottom slab to improve the reliability of the connection.

[0015] Preferably, the connecting rod one and connecting rod two of the anchor claw structure are connected by a high-strength pin, and the surface of the pin is coated with grease.

[0016] Preferably, the lead screw motor drive device is equipped with an overload protection module. When the anchor claw encounters extreme resistance during deployment, the motor body automatically stops to avoid overload damage to the equipment and ensure construction safety.

[0017] To achieve the above objectives, the present invention also provides the following technical solution:

[0018] A construction method for reinforcing existing underground structures with anti-buoyancy steel pipe pile structures includes the following steps:

[0019] Step 1: Construction preparation, testing the parameters of the existing underground structure slab, investigating the engineering geological and hydrogeological conditions, determining the construction parameters, preparing low-headroom construction equipment and materials, and conducting at least 3 test piles; if the water level is high during the construction of steel pipe piles, dewatering wells should be set up to ensure the construction effect of steel pipe piles.

[0020] Step 2: Open holes in the existing structural base plate, according to the design positioning, with a hole diameter not exceeding 400mm;

[0021] Step 3: Driving the main body of the steel pipe pile. The main body of the steel pipe pile with top push rod is driven into the pile section by section using an anchor static pressure pile driver and then welded and fixed to ensure that the designed penetration depth is reached.

[0022] Step 4: Install the lead screw motor drive and jacking transmission components, ensuring a tight connection and smooth force transmission;

[0023] Step 5: Start the screw motor drive device, push the push rod downward, drive the anchor claw to unfold and embed into the surrounding soil, forming a dual pull-out resistance structure of "pile side friction resistance + anchor claw anchoring force";

[0024] Step Six: Disassemble the core components such as the lead screw motor drive unit and connecting rod, clean them, and then transfer them to the next steel pipe pile for construction and reuse.

[0025] Step 7: Pour C30 concrete into the core of the steel pipe piles in sections, and test the pull-out bearing capacity and construction quality of the steel pipe piles to ensure that they meet the design requirements. After the strength reaches the standard, seal the piles with C35 concrete.

[0026] The present invention has the following advantages:

[0027] It has excellent spatial adaptability: the entire construction process uses low-headroom anchor static pressure pile drivers. The core device is compact in size and can be fully adapted to the construction environment with limited headroom in existing underground structures, solving the problem that conventional tall equipment cannot be used for construction.

[0028] The pull-out bearing capacity is greatly improved: the "screw motor push-driven anchor claw deployment" design has direct force transmission and large deployment force. After the anchor claw is embedded in the soil, it forms a dual pull-out resistance mechanism, which significantly improves the pull-out bearing capacity compared with traditional steel pipe piles and can meet the high anti-buoyancy requirements.

[0029] Reusable components: The screw motor drive device, connecting rod and other components are easy to disassemble and assemble, do not need to be solidified with the pile body, and can be reused in the construction of multiple steel pipe piles, which greatly reduces the waste of consumables;

[0030] Highly efficient and cost-effective construction: The overall structure of the device is simple, the anchor claws are easy to process and install, the construction process is clear, no complicated procedures are required, and the construction period is not extended; at the same time, conventional steel and concrete are used as materials, the cost is controllable, and construction quality and efficiency are balanced.

[0031] Minimal disturbance and high safety: The construction process involves minimal vibration and noise, and the small diameter of the openings in the base plate minimizes disturbance to the existing structure and the surrounding environment, ensuring the safety of the original structure and the stability of the construction environment. Attached Figure Description

[0032] To more intuitively illustrate the prior art and this application, exemplary drawings are provided below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing this application; for example, based on the technical concept disclosed in this application and the exemplary drawings, those skilled in the art are able to easily make conventional adjustments or further optimizations to the addition / reduction / classification, specific shapes, positional relationships, connection methods, size ratios, etc. of certain units (components).

[0033] Figure 1 A flowchart of a construction method for an existing underground structure screw motor driven deployment of anchor claw anti-buoyancy steel pipe pile structure provided in this application embodiment;

[0034] Figure 2 A schematic diagram of the overall structure of the existing underground structure screw motor driven deployment of anchor claw anti-buoyancy steel pipe pile structure provided in the embodiments of this application;

[0035] Figure 3 A top view of the pad of the existing underground structure screw motor driven deployment anchor claw anti-buoyancy steel pipe pile structure provided in the embodiments of this application;

[0036] Figure 4The top view of the existing underground structure screw motor driven anti-buoyancy steel pipe pile structure provided in the embodiment of this application, after all the anchor claws are opened.

[0037] In the diagram: 1. Motor body; 2. Lead screw; 3. Ball nut; 4. Connector between lead screw and push rod; 5. Push rod; 6. Steel pipe pile body; 7. Underground structure base plate; 8. Anchor claw structure; 11. Motor cable; 41. Pad 1; 42. Pad 2; 43. Locking nut; 44. Connecting rod between lead screw drive device and push rod; 45. Pad 3; 46. Clamping plate; 61. Steel pipe pile wall; 62. Anchoring reinforcement; 63. Steel pipe pile section connection point; 81. Anchor claw structure clamping plate; 82. Five-hole pin seat; 83. Pin lug plate; 84. Connecting rod 1; 85. Connecting rod 2; 86. Pin hole. Detailed Implementation

[0038] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that these embodiments are merely for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Technical engineers in the field can make some non-essential improvements and adjustments to the present invention based on the above-described content. 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.

[0039] This invention discloses an existing underground structure with a screw motor-driven anchor claw anti-buoyancy steel pipe pile structure and its construction method. For example... Figure 1 The construction process is as follows: construction preparation, bottom slab drilling, steel pipe pile driving, drive and transmission component installation, anchor claw deployment and anchoring, core component recovery, core filling and pile sealing, and quality inspection. No large equipment is required throughout the process, making it suitable for existing underground structures with limited space.

[0040] like Figure 2 As shown, the anti-buoyancy steel pipe pile structure includes a steel pipe pile body 6, a screw motor drive device, a jacking transmission assembly, and an anchor claw structure 8. The steel pipe pile body 6 has a pipe diameter of 299mm, a wall thickness of 8mm, and an open end. The pile section length is 2m. The length of each jacking rod 5 is the same as that of the steel pipe pile. The connection between each pile section is made by angle steel bevel welding. The jacking rod 5 is welded, and the weld has been tested for non-destructive testing and found to be free of defects such as cracks and slag inclusions. Six anchoring steel bars 62 are welded to the top of the steel pipe pile, evenly distributed along the circumference. The anchoring steel bars 62 are HRB400 φ20mm and are anchored into the existing underground structure bottom slab 7 for a length of 800mm. After construction, C35 concrete is poured to seal the pile.

[0041] like Figure 2 ,3 As shown, the lead screw 2 of the lead screw motor drive device is connected to the output end of the motor body 1. The ball nut 3 is sleeved on the outside of the lead screw 2 and fixed to the lead screw and push rod connecting part 4. The lead screw and push rod connecting part 4 consists of a first pad 41, a second pad 42, a third pad 45, a locking nut 43, and a lead screw drive device and push rod connecting rod 44. The hole diameter of the first pad 41 is slightly larger than the diameter of the lead screw 2, the hole diameter of the second pad 42 is slightly larger than the outer diameter of the ball nut 3, and the hole diameter of the third pad 45 is the same as the diameter of the push rod 5. The three pads are each connected and fixed by four bolts. The clamping plate 46 adopts a 20CrMnTi carburized steel slotted structure to fasten the push rod 5 to the third pad 45, which directly transmits force and is convenient to disassemble and assemble.

[0042] like Figure 2 , 4 As shown, the anchor claw structure 8 is a five-claw symmetrical design. The pin lug plate 83 is welded to the steel pipe pile wall 61. The five-hole pin seat 82 is fixed to the bottom of the push rod 5 through the anchor claw structure clamping plate 81. The two ends of the connecting rod 1 84 are respectively hinged to the pin lug plate 83 and the connecting rod 2 85 through pin shafts. The other end of the connecting rod 2 85 is hinged to the five-hole pin seat 82. When the push rod 5 moves downward, it pushes the five-hole pin seat 82 downward, which drives the connecting rod 2 85 to unfold outward through the connecting rod 1 84 until the anchor claw is completely embedded in the surrounding soil, forming a stable anchor.

[0043] The construction principle of this invention is as follows: Before construction, the optimal parameters are determined through engineering geology, hydrogeology conditions, and test piles. During construction, holes with a diameter of 400mm are first drilled in the underground structure base plate 7. An anchor-mounted static pressure pile driver is used to sink the steel pipe pile body 6, which contains the jacking rod 5, into the design depth section by section. Each pile section and each jacking rod 5 are welded and fixed. A screw motor drive device and a jacking transmission assembly are installed. The motor body 1 is started to drive the screw 2 to rotate. The ball nut 3 drives the jacking rod 5 to move downward, thereby pushing the anchor claw structure 8 to unfold and embed into the soil. That is, the axial movement of the jacking rod 5 in the center of the steel pipe pile body 6 is used to convert the force into the radial movement of the anchor claw structure 8, thereby opening the anchor claw around the pipe pile, thereby increasing the resistance of the steel pipe pile and forming a double anti-pull-out mechanism. After the anchor claw is unfolded into place, the drive device and transmission assembly are disassembled and transferred to the next pile for reuse. Finally, the steel pipe pile body 6 is filled and sealed with core and subjected to quality inspection to ensure the anti-buoyancy reinforcement effect.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An existing underground structure with screw motor-driven deployment of anchor claws and anti-buoyancy steel pipe pile structure, characterized in that, It includes the main body of the steel pipe pile (6), the screw motor drive device, the jacking transmission assembly, and the anchor claw structure (8). The main body of the steel pipe pile (6) has an open end, which is suitable for the construction of low-headroom small equipment anchor rod static pressure pile machine; 4 to 6 anchoring steel bars (62) are welded to the top of the main body of the steel pipe pile (6), which are evenly distributed along the main body of the steel pipe pile (6) and anchored to the bottom plate of the underground structure (7), with an anchoring length of not less than 39d; The lead screw motor drive device includes a motor body (1), a motor cable (11), a lead screw (2), and a ball nut (3). The jacking transmission assembly consists of a lead screw and jacking rod connector (4) and a jacking rod (5). The end of the jacking rod (5) is tapered to form a guide head, which facilitates cutting into the soil layer. The lead screw (2) and jacking rod (5) connector consists of three pads with different hole diameters: pad 1 (41), pad 2 (42), pad 3 (45), a locking nut (43), and a lead screw drive device and jacking rod connector 44. The hole diameter of pad 1 (41) is larger than the diameter of the lead screw (2), the hole diameter of pad 2 (42) is larger than the outer diameter of the ball nut, and the hole diameter of pad 3 (45) is equal to the diameter of the jacking rod (5). The clamping plate (46) forms a clamping anchor plate. The length of a single section of the push rod (5) is consistent with that of the main body (6) of the steel pipe pile. The connection of each section of the main body (6) of the steel pipe pile is made by angle steel bevel welding, and the push rod (5) is welded. The anchor claw structure (8) is a five-claw symmetrical structure, including a pin ear plate (83) welded to the wall of the steel pipe pile body (6), a five-hole pin seat (82) connected to the push rod (5), a connecting rod one (84), and a connecting rod two (85); the five-hole pin seat (82) and the push rod (5) are clamped by the anchor claw structure clamping plate (81); the anchor claw structure clamping plate (81) is a slotted structure; the anchor claw is pushed and driven to unfold by the motor body (1).

2. The existing underground structure screw motor driven deployment anchor claw anti-buoyancy steel pipe pile structure according to claim 1, characterized in that, The anchoring steel bars (62) of the main body of the steel pipe pile (6) are finally anchored into the bottom plate of the underground structure (7).

3. The existing underground structure screw motor driven deployment anchor claw anti-buoyancy steel pipe pile structure according to claim 1, characterized in that, The anchor claw structure (8) is connected by a high-strength pin between the first connecting rod (84) and the second connecting rod (85), and the pin surface is coated with grease.

4. The existing underground structure screw motor driven deployment anchor claw anti-buoyancy steel pipe pile structure according to claim 1, characterized in that, The lead screw motor drive device is equipped with an overload protection module. When the anchor claw structure (8) encounters extreme resistance during unfolding, the motor body (1) will automatically stop.

5. A construction method for reinforcing existing underground structures against buoyancy using the anti-buoyancy steel pipe pile structure described in any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Construction preparation, testing the parameters of the existing underground structure slab (7), investigating the engineering geological and hydrogeological conditions, determining the construction parameters, preparing low-headroom construction equipment and materials, and testing no less than 3 piles; if the water level is high during the construction of steel pipe piles, set up dewatering wells to ensure the construction effect of steel pipe piles; Step 2: Open holes in the existing structural base plate, according to the design positioning, with a hole diameter not exceeding 400mm; Step 3: Piling the main body (6) of the steel pipe pile. The main body (6) of the steel pipe pile with top push rod (5) is driven into the pile section by section using an anchor static pressure pile machine and welded and fixed to ensure that the designed penetration depth is reached. Step 4: Install the lead screw motor drive and jacking transmission components, ensuring a tight connection and smooth force transmission; Step 5: Start the screw motor drive device (1), push the push rod (5) downward, drive the anchor claw to unfold and embed into the surrounding soil, forming a double pull-out resistance structure of "pile side friction resistance + anchor claw anchoring force"; Step Six: Disassemble the lead screw motor drive unit and connecting rod core components, clean them, and then transfer them to the next steel pipe pile for construction and reuse. Step 7: Pour C30 concrete into the core of the steel pipe pile in sections, test the pull-out bearing capacity and construction quality of the steel pipe pile to ensure that it meets the design requirements, and seal the pile with C35 concrete after the strength reaches the standard.

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