Reuleaux triangle drilling type grouting spiral pile core stiff composite square pile forming device and method

Abstract

The invention relates to a Reuleaux triangle drilling type grouting spiral pile core stiff composite square pile forming device which comprises a first-section spiral pile core assembly and a Reuleaux triangle drill bit assembly. The first-section spiral pile core assembly comprises a first-section inner steel pipe and a first-section outer steel pipe which are coaxially arranged inside and outside; the upper end and the lower end of the first-section inner steel pipe are rotationally connected with the inner wall of the first-section outer steel pipe through first-section rolling bearings, spiral blades are arranged on the outer wall of the first-section outer steel pipe in a surrounding mode, the lower end of the first-section inner steel pipe is fixed to the Reuleaux triangle drill bit assembly, and grouting holes are formed in the side face of a Reuleaux triangle drill bit of the Reuleaux triangle drill bit assembly. The spiral pile has the beneficial effects that the spiral pile core design and the grouting technology are combined, soil can be effectively discharged in the drilling process, a strong cement soil pile periphery structure can be formed through grouting, the bearing capacity and stability of a pile foundation are greatly improved, and the spiral pile is suitable for building and foundation engineering under various complex geological conditions.

Description

Technical Field

[0001] This invention relates to the field of engineering pile foundation technology, specifically to a Reuleaux triangular borehole grouting spiral pile core stiffness composite square pile forming device and method. Background Technology

[0002] Helical core reinforced composite piles are a new type of pile foundation structure that combines the advantages of helical piles and reinforced composite materials. Their working principle involves a high-strength steel helical core. During drilling, external helical blades cut and expel soil debris, simultaneously mixing the soil with cement grout to form cement-soil around the pile, enhancing the stability and bearing capacity of the pile foundation. Their high construction efficiency makes them suitable for various scenarios such as high-rise buildings, bridges, ports, soft soil foundation treatment, and earthquake-resistant engineering. However, some problems still exist in existing technologies: traditional drill bit designs are prone to borehole deformation during drilling, affecting the installation and stability of the pile foundation; the grouting process is complex, making it difficult to guarantee construction efficiency and grouting quality; and their adaptability in both soft and hard soils is also limited.

[0003] Square piles are a type of pile foundation structure with a square cross-section. Compared with spiral piles and core-stiffened composite piles, square piles have some unique advantages. First, square piles have high bearing capacity, and their cross-sectional shape gives them a larger contact area, enabling them to better distribute and bear loads. Second, square piles have better bending resistance under bending moment than round piles, especially under large horizontal loads, where their bending stiffness is higher. In addition, square piles are easier to maintain their shape during drilling, avoiding hole wall collapse and facilitating smooth construction. However, square piles also have some disadvantages, such as poor adaptability to soft and hard soils using traditional construction methods, low construction efficiency, and difficulty in comprehensive application under complex geological conditions.

[0004] In recent years, composite piles have gradually attracted attention as a new construction method, aiming to solve engineering problems under complex geological conditions by utilizing the advantages of different pile foundations. Combining the advantages of helical core-reinforced composite piles with square piles is a new approach to replace traditional pile foundations. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a pile-forming device and method for Reuleaux triangular borehole grouting spiral pile core stiffness composite square pile, so as to overcome the shortcomings of the prior art.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A Reuleaux triangular drilling grouting spiral pile core rigid composite square pile forming device, comprising: a first section spiral pile core assembly and a Reuleaux triangular drill bit assembly. The first section spiral pile core assembly comprises: a first section inner steel pipe and a first section outer steel pipe arranged coaxially inside and outside. The upper and lower ends of the first section inner steel pipe are rotatably connected to the inner wall of the first section outer steel pipe through a first section rolling bearing. Spiral blades are arranged around the outer wall of the first section outer steel pipe. The lower end of the first section inner steel pipe is fixed to the Reuleaux triangular drill bit assembly. Grouting holes are opened on the side of the Reuleaux triangular drill bit of the Reuleaux triangular drill bit assembly.

[0007] Based on the above technical solution, the present invention can be further improved as follows.

[0008] Furthermore, the Reuleaux triangular drill bit assembly includes: a Reuleaux triangular drill bit and a grouting rod. The Reuleaux triangular drill bit has a cutting edge and a drilling surface. The outlet end of the grouting rod is connected to the grouting hole inlet on the Reuleaux triangular drill bit. The Reuleaux triangular drill bit is connected to the inner steel pipe of the first section via a coupling and the inlet end of the grouting rod.

[0009] Furthermore, the Reuleaux triangle drill bit has a Reuleaux triangle side length. a Not less than the diameter of the helical blade D H The centroid P of the Reuleaux triangle is eccentrically offset r from the center O of the square hole by no more than 0.5a. The remaining length of the cutting edge on the Reuleaux triangle drill bit is 2 / 3 to 3 / 4 of the side length of the Reuleaux triangle. The angle of the drilling face on the Reuleaux triangle drill bit is 15° to 30°.

[0010] Furthermore, the spacing between the helical blades on the first section of the helical pile core assembly... S H The diameter of the helical blade is 1 to 2 times that of the helical blade. The number of helical blades on the first section of the helical pile core assembly is 2 to 3, the inclination angle of the helical blade is 10° to 30°, and the diameter of the helical blade is... D H It is 3 to 4 times the outer diameter of the first section of the spiral pile core assembly.

[0011] Furthermore, the Reuleaux triangular drill bit is made of high-strength alloy steel or cemented carbide, and the spiral blades are made of wear-resistant alloy steel or high-strength steel.

[0012] Furthermore: the Reuleaux triangular drill bit has a surface hardening treatment and an anti-corrosion coating, and the helical blade surface has an anti-corrosion coating and a wear-resistant coating.

[0013] Furthermore, the outer steel pipe of the first section is made of carbon steel or low alloy steel, the inner steel pipe of the first section is made of carbon steel or low alloy steel, and the rolling bearing of the first section is made of high carbon chromium bearing steel. Furthermore, the surfaces of the outer and inner steel pipes of the first section have anti-corrosion coatings, and the surface of the rolling bearing of the first section has both anti-corrosion coatings and lubrication coatings.

[0014] Furthermore, the material of the slurry delivery rod is corrosion-resistant steel or alloy steel that has undergone anti-corrosion treatment.

[0015] Furthermore, the surface of the grout delivery rod has an anti-corrosion coating.

[0016] Furthermore, at least one extension section spiral pile core assembly is detachably coaxially connected to the upper end of the first section spiral pile core assembly. The extension section spiral pile core assembly includes an inner and an outer steel pipe arranged coaxially. The upper and lower ends of the inner steel pipe are rotatably connected to the inner wall of the outer steel pipe via rolling bearings. Spiral blades are arranged around the outer wall of the outer steel pipe. Extension section nuts are located at the upper and lower ends of both the outer and inner steel pipes. A first section nut is located at the upper end of both the first outer and inner steel pipes. The threaded hole size of the extension section nut is the same as that of the first section nut. The extension section spiral pile core assembly located at the bottom extends... The extension section nut at the lower end of the outer steel pipe is connected to the first section nut at the upper end of the first outer steel pipe via a hollow screw rod. The extension section nut at the lower end of the inner steel pipe in the lowest extension section spiral pile core assembly is connected to the first section nut at the upper end of the inner steel pipe via a hollow screw rod. Between two adjacent extension section spiral pile core assemblies, the extension section nut at the lower end of the outer steel pipe in the upper extension section spiral pile core assembly is connected to the extension section nut at the upper end of the outer steel pipe in the lower extension section spiral pile core assembly via a hollow screw rod. Between two adjacent extension section spiral pile core assemblies, the extension section nut at the lower end of the inner steel pipe in the upper extension section spiral pile core assembly is connected to the extension section nut at the upper end of the inner steel pipe in the lower extension section spiral pile core assembly via a hollow screw rod.

[0017] Furthermore, the spacing between the helical blades on the extended section of the helical pile core assembly... S H The diameter of the spiral blade is 1 to 2 times that of the spiral blade. The extended section of the spiral pile core assembly has 2 to 3 spiral blades, with an inclination angle of 10° to 30° and a diameter of 1 to 2 times the diameter of the spiral blade. D H It is 3 to 4 times the outer diameter of the extended section of the spiral pile core assembly.

[0018] Furthermore, the surfaces of the outer steel pipe and the inner steel pipe of the extension section are coated with an anti-corrosion coating, and the surfaces of the rolling bearings of the extension section are coated with both an anti-corrosion coating and a lubricating coating.

[0019] Furthermore, the first section nut, the extension section nut, and the hollow screw are made of alloy steel or surface-hardened steel.

[0020] Furthermore, the first section nut, the extension section nut, and the hollow screw have anti-corrosion coatings and surface hardening treatments.

[0021] Furthermore, the length of the first section of the helical pile core assembly is 1m to 3m, and the outer diameter of the first section of the outer steel pipe is... d 1 is 200mm~300mm, the outer diameter of the inner steel pipe of the first section. d 2 is 100mm~150mm, the length of the extended section spiral pile core assembly is 1m~3m, and the outer diameter of the extended section outer steel pipe is... d 1 represents the outer diameter of the steel pipe within the extended section, which is 200mm to 300mm. d 2 is 100mm to 150mm.

[0022] Furthermore, the Reuleaux triangular drill bit has three grouting holes on its side, with an inner diameter of 3mm to 5mm.

[0023] Based on the above technical solution, the present invention also provides a method for forming a Reuleaux triangular drilled grouting spiral pile core-strength composite square pile, which uses the above-mentioned Reuleaux triangular drilled grouting spiral pile core-strength composite square pile forming device and includes the following steps: First, align the Reuleaux triangular drill bit with the construction point. Then, connect the drilling rig to the upper end of the first outer steel pipe and the first inner steel pipe. At the same time, start the grouting equipment and supply grout into the grouting hole. During the operation, the drilling and grouting are carried out simultaneously until the designed pile foundation depth is reached.

[0024] Furthermore, if the first section of the spiral pile core assembly fails to reach the final designed pile foundation depth despite the cooperation of the first section of the spiral pile core assembly and the Reuleaux triangular drill bit assembly, then firstly, one section of the extended spiral pile core assembly is coaxially aligned with the first section of the spiral pile core assembly. Then, the lower end of the hollow screw is threadedly connected to the first nut on the first section of the spiral pile core assembly, and the upper end of the hollow screw is threadedly connected to the extended nut at the lower end of the extended spiral pile core assembly. This allows an extended spiral pile core assembly to be attached to the first section of the spiral pile core assembly. Subsequently, the drilling rig is connected to the upper end of the outer steel pipe and the inner steel pipe of the extended section, and the grouting equipment is started simultaneously. During the operation, drilling and grouting are performed concurrently until the designed pile foundation depth is reached. Then, another extended spiral pile core assembly is installed on the upper end of the extended spiral pile core assembly, and so on, while simultaneously starting the grouting equipment. During the operation, drilling and grouting are performed concurrently until the final designed pile foundation depth is reached.

[0025] The beneficial effects of this invention are: 1) The Reuleaux triangle drill bit design provides a constant width of drilling. This design can effectively form square holes, improving drilling accuracy and efficiency. In addition, the unique geometry of the Reuleaux triangle allows the drill bit to distribute cutting force evenly during rotation, reducing energy consumption and improving work efficiency. 2) The combination of spiral pile core design and grouting process can not only effectively remove soil during drilling, but also form a strong cement-soil pile perimeter structure through grouting, which greatly enhances the bearing capacity and stability of the pile foundation and is suitable for building and foundation engineering under various complex geological conditions. 3) The use of rolling bearings allows the inner and outer steel pipes to rotate independently, effectively reducing friction and resistance during operation. This design not only improves the stability of construction but also reduces the wear of mechanical equipment and extends its service life. At the same time, the sealing design of the rolling bearings prevents the entry of mud, water and dust, further improving the reliability of the system. 4) The component design features modularity. The first section of the helical pile core component and the multiple extension sections of the helical pile core component can be flexibly combined to adapt to construction needs of different depths and diameters. This modular design simplifies assembly and disassembly during construction, improving construction efficiency and flexibility. 5) The Reuleaux triangle drill bit is the core component for cutting and drilling, so it is made of high-strength alloy steel or cemented carbide. This not only extends the service life of the drill bit but also reduces the frequency of replacement, thereby reducing costs. The helical blades are responsible for cutting and expelling the soil. The materials used should be able to withstand friction and pressure, and also be wear-resistant to reduce the need for frequent replacements and reduce energy consumption during construction. Therefore, wear-resistant alloy steel or high-strength steel are selected as the materials. The selection of materials with appropriate strength and corrosion resistance for both outer and inner steel pipes can control material costs while ensuring structural stability. Appropriate material selection can also reduce losses caused by corrosion and lower maintenance costs. Rolling bearings need to remain stable under high loads and long-term operation. The selection of wear-resistant materials can extend the bearing's life, reduce equipment wear and replacement frequency, and lower overall maintenance costs. Therefore, high carbon chromium bearing steel, such as GCr15, is selected as the material. Since the first section nut, extension section nut and hollow screw need to have high strength and wear resistance to ensure that they are not easily damaged in high-intensity operations and reduce maintenance and replacement costs, alloy steel or surface-hardened steel is selected as the material. To ensure that the grout delivery rod is not corroded during long-term contact with grout, the material selection should be primarily corrosion-resistant, thereby reducing equipment wear caused by corrosion. Therefore, the material of the grout delivery rod is corrosion-resistant steel or alloy steel that has undergone anti-corrosion treatment. Applying an anti-corrosion coating to the exterior of steel structures in marine or highly corrosive environments protects them from corrosion. Especially in marine or highly corrosive environments, a suitable coating not only protects the equipment but also reduces the frequency of equipment replacement due to corrosion. Therefore, the material of the anti-corrosion coating is epoxy resin or polyurethane coating.

[0026] Therefore, by optimizing the design and material selection, the manufacturing cost of drill bits and pile cores can be effectively reduced, while energy consumption and equipment wear and tear during construction can be reduced. This not only reduces the overall construction cost but also reduces the frequency of equipment maintenance and replacement, thereby improving economic efficiency. 6) The design fully considers the adaptability to different geological environments. The Reuleaux triangular drill bit is surface hardened (such as carburizing and nitriding) and coated with anti-corrosion coating (ceramic coating or titanium nitride coating) to ensure that the Reuleaux triangular drill bit can effectively cut the soil during the pile driving process, while resisting the corrosive environment and ensuring the smooth progress of the pile driving process. The surface of the helical blades has an anti-corrosion coating (such as epoxy coating or polyurethane coating) and a wear-resistant coating (tungsten carbide coating), which ensures that the helical blades can effectively cut and expel the soil during the pile construction process, while preventing environmental corrosion from affecting the stability of the pile foundation. The surfaces of the first outer steel pipe and the first inner steel pipe are coated with anti-corrosion coatings (such as epoxy resin coating or galvanizing) to ensure that the first outer steel pipe and the first inner steel pipe are protected from corrosion damage during the pile-forming process, especially in environments where they are in contact with soil and groundwater for a long time. The surface of the first rolling bearing has an anti-corrosion coating (such as PVD coating) and a lubrication coating (such as solid lubricant coating) to ensure the smooth operation and durability of the bearing during the piling process and prevent operational failure due to corrosion. The first section nut, extension section nut, and hollow screw have anti-corrosion coatings (such as zinc or nickel plating) and surface hardening treatment to ensure the reliability and corrosion resistance of these components during connection and pile formation. The grouting rod has an anti-corrosion coating (such as epoxy coating or fluorocarbon coating) on ​​its surface to ensure the corrosion resistance of the grouting rod during the grouting process and prevent failure caused by grout corrosion; By rationally selecting the materials and coatings for these key components, the reliability and long-term stability of the pile foundation during the one-time pile-forming process can be ensured, and the integrity and bearing capacity of the pile foundation structure can still be maintained even in extremely corrosive environments. Attached Figure Description

[0027] Figure 1 This is a structural diagram of the Reuleaux triangular borehole grouting spiral pile core stiffness composite square pile forming device of the present invention; Figure 2 for Figure 1 Top view of the middle section of the structure; Figure 3This is a structural diagram of the Reuleaux triangle drill bit in this invention; Figure 4 This is a schematic diagram of the Reuleaux triangle drill bit parameter design in this invention; Figure 5 This is a structural diagram of a spiral pile core assembly with multiple extension sections connected sequentially on the first spiral pile core assembly in this invention; Figure 6 This is a structural diagram of the extended section helical pile core assembly in this invention; Figure 7 This is a schematic diagram of the biaxial spiral grouting process of the Reuleaux triangular drilling grouting spiral pile core stiffness composite square pile forming device in this invention; Figure 8 This is a schematic diagram of the installation process of the Reuleaux triangular borehole grouting spiral pile core stiffness composite square pile forming device in this invention.

[0028] The attached diagram lists the components represented by each number as follows: 1. First section of spiral pile core assembly, 110. First section inner steel pipe, 120. First section outer steel pipe, 130. First section rolling bearing, 140. First section nut, 2. Reuleaux triangular drill bit assembly, 210. Reuleaux triangular drill bit, 211. Grouting hole, 212. Cutting edge, 213. Drilling face, 220. Grouting rod, 230. Coupling, 3. Spiral blade, 4. Extension section spiral pile core assembly, 410. Extension section inner steel pipe, 420. Extension section outer steel pipe, 430. Extension section nut, 440. Extension section rolling bearing, 5. Hollow screw, 6. Downward pressing power, 7. Outer steel pipe pile turning torque, 8. Inner steel pipe pile turning torque, 9. Cement soil, 10. Cement grout. Detailed Implementation

[0029] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0030] Example 1 like Figure 1 , Figure 2 , Figure 3As shown, a Reuleaux triangular drill-type grouting spiral pile core rigid composite square pile forming device includes: a first-section spiral pile core assembly 1 and a Reuleaux triangular drill bit assembly 2. The first-section spiral pile core assembly 1 includes: a first-section inner steel pipe 110 and a first-section outer steel pipe 120. The first-section inner steel pipe 110 and the first-section outer steel pipe 120 are arranged coaxially inside and outside. The upper end of the first-section inner steel pipe 110 is rotatably connected to the inner wall of the first-section outer steel pipe 120 via a first-section rolling bearing 130. The lower end of the first-section inner steel pipe 110 is rotatably connected to the inner wall of the first-section outer steel pipe 120 via the first-section rolling bearing 130. Specifically, the outer ring of the first-section rolling bearing 130 is fixedly connected to the inner wall of the first-section outer steel pipe 120, while the inner ring of the first-section rolling bearing 130 is fixedly sleeved. On the outer wall of the first inner steel pipe 110, the first inner steel pipe 110 can rotate along the axis inside the first outer steel pipe 120; the outer wall of the first outer steel pipe 120 is surrounded by a spiral blade 3, the lower end of the first inner steel pipe 110 is fixed to the Reuleaux triangle drill bit assembly 2, and the Reuleaux triangle drill bit 210 of the Reuleaux triangle drill bit assembly 2 has a grouting hole 211 on its side. The Reuleaux triangle is a curve of equal width, which is formed by drawing arcs with the adjacent vertex as the center and the side length as the radius at each vertex of an equilateral triangle. The width of the shape formed is equal in any direction, that is, its width remains constant no matter which direction it is rotated to. The first inner steel pipe 110 and the first outer steel pipe 120 of the first spiral pile core assembly 1 are driven by the inner and outer rotating drilling machine.

[0031] Example 2 like Figure 1 , Figure 2 , Figure 3 As shown, this embodiment is a further improvement on embodiment 1, as detailed below: The Reuleaux triangular drill bit assembly 2 includes a Reuleaux triangular drill bit 210 and a grouting rod 220. The Reuleaux triangular drill bit 210 has a cutting edge 212 and a drilling surface 213. The cutting edge 212 is formed by an arc cut from the vertex of the Reuleaux triangle, and the drilling surface 213 is formed by a bevel cut. The outlet end of the grouting rod 220 is connected to the inlet of the grouting hole 211 on the Reuleaux triangular drill bit 210. The Reuleaux triangular drill bit 210 is connected to the first section of the inner steel pipe 110 via a coupling 230 and the inlet end of the grouting rod 220. When the first section of the inner steel pipe 110 rotates, the Reuleaux triangular drill bit 210 will rotate synchronously along the axis via the coupling 230 and the grouting rod 220.

[0032] Example 3 like Figure 3 , Figure 4 As shown, this embodiment is a further improvement on embodiment 2, as detailed below: The polar equation of the Reuleaux triangle is:

[0033] in, Let be the side length of the Reuleaux triangle. It is the polar angle. Let (0, 1, 2) be integers corresponding to different sides of the Reuleaux triangle. This equation shows that the Reuleaux triangle's constant-width property causes it to form a rectangular hole of constant width upon rotation, with the side length of the hole equal to the side length of the Reuleaux triangle. ; The Reuleaux triangle side length of the Reuleaux triangle drill bit 210 a The diameter of the helical blade 3 is not less than D H To ensure that the spiral blade 3 can smoothly pass through the hole during drilling and complete the soil discharge and mixing process, in this embodiment, the side length of the Reuleaux triangle is... The centroid P of the Reuleaux triangle is 900 mm. The eccentricity r of the centroid P relative to the center O of the square hole is no greater than 0.5a. In this embodiment, the eccentricity r of the centroid P to the center O of the rectangle is set to 45 mm, which is equivalent to 1 / 20 of the side length of the Reuleaux triangle. The remaining length of the cutting edge 212 on the Reuleaux triangle drill bit 210 is 2 / 3 to 3 / 4 of the side length of the Reuleaux triangle. In this embodiment, the remaining length of the cutting edge 212 is... l The diameter is set to 675mm, approximately 3 / 4 of the side length. The angle of the drilling facet 213 on the Reuleaux triangular drill bit 210 is 15° to 30°. In this embodiment, the angle of the drilling facet 213 is... It is 20°.

[0034] Example 4 like Figure 1 , Figure 3 As shown, this embodiment is a further improvement on any one of embodiments 1 to 3, as detailed below: The spacing of the helical blades 3 on the first section of the helical pile core assembly 1 S H The diameter of the spiral blade 3 is 1 to 2 times that of the spiral core assembly 1. The number of spiral blades 3 on the first section of the spiral core assembly 1 is 2 to 3, the inclination angle of the spiral blades 3 is 10° to 30°, and the diameter of the spiral blades 3 is... D H It is 3 to 4 times the outer diameter of the first section of the spiral pile core assembly 1.

[0035] As a preferred option: the diameter of the helical blade 3 D H The spacing of the spiral blades is 875mm (equivalent to 3.5 times the outer diameter of the first section of the outer steel pipe of 120mm). S HThe diameter was set to 1312.5 mm (i.e., 1.5 times the diameter of the helical blade 3), and three helical blades 3 were installed, each with an inclination angle of 20°. Example 5 like Figure 1 As shown, this embodiment is a further improvement on any one of embodiments 1 to 4, as detailed below: The Reuleaux triangular drill bit 210 is made of high-strength alloy steel or cemented carbide, while the spiral blade 3 is made of wear-resistant alloy steel or high-strength steel. The Reuleaux triangular drill bit 210 is the core component for cutting and drilling, hence the selection of high-strength alloy steel or cemented carbide. This not only extends the drill bit's service life but also reduces replacement frequency, thereby lowering costs. The spiral blade 3 is responsible for cutting and expelling the soil; its material should be able to withstand friction and pressure while also being wear-resistant to reduce the need for frequent replacements and lower energy consumption during construction. Therefore, wear-resistant alloy steel or high-strength steel is selected. The Reuleaux triangular drill bit 210 has a surface hardening treatment and an anti-corrosion coating, while the spiral blade 3 has both an anti-corrosion coating and a wear-resistant coating.

[0036] The material of the first outer steel pipe 120 is carbon steel or low alloy steel, the material of the first inner steel pipe 110 is carbon steel or low alloy steel, the material of the first rolling bearing 130 is high carbon chromium bearing steel, the surface of the first outer steel pipe 120 and the first inner steel pipe 110 has an anti-corrosion coating, the surface of the first rolling bearing 130 has an anti-corrosion coating and a lubrication coating, the material of the slurry conveying rod 220 is corrosion-resistant steel or alloy steel treated with anti-corrosion, and the surface of the slurry conveying rod 220 has an anti-corrosion coating.

[0037] Example 6 like Figure 5 , Figure 6 As shown, this embodiment is a further improvement on any one of embodiments 1 to 5, as detailed below: The upper end of the first section of the helical pile core assembly 1 is detachably coaxially connected to at least one extension section of the helical pile core assembly 4. The extension section of the helical pile core assembly 4 includes an inner steel pipe 410 and an outer steel pipe 420. The inner steel pipe 410 and the outer steel pipe 420 are arranged coaxially inside and outside. The upper end of the inner steel pipe 410 is rotatably connected to the inner wall of the outer steel pipe 420 via an extension section rolling bearing 440. The lower end of the inner steel pipe 410 is rotatably connected to the inner wall of the outer steel pipe 420 via the extension section rolling bearing 440. Specifically, the outer ring of the extension section rolling bearing 440 is fixed to the inner wall of the outer steel pipe 420. The inner ring of the extended section rolling bearing 440 is fixedly sleeved on the outer wall of the extended section inner steel pipe 410. At this time, the extended section inner steel pipe 410 can rotate along the axis inside the extended section outer steel pipe 420. The outer wall of the extended section outer steel pipe 420 is surrounded by helical blades 3. The upper and lower ends of the extended section outer steel pipe 420 are respectively provided with extended section nuts 430, the upper and lower ends of the extended section inner steel pipe 410 are respectively provided with extended section nuts 430, the upper end of the first section outer steel pipe 120 is provided with a first section nut 140, the upper end of the first section inner steel pipe 110 is provided with a first section nut 140, and the thread hole size of the extended section nut 430 is the same as the thread hole size of the first section nut 140. Both the section nut 430 and the first section nut 140 are high-strength nuts. The section nut 430 at the lower end of the outer steel pipe 420 in the lowest extension section spiral pile core assembly 4 is connected to the first section nut 140 at the upper end of the outer steel pipe 120 via a hollow screw rod 5. Similarly, the section nut 430 at the lower end of the inner steel pipe 410 in the lowest extension section spiral pile core assembly 4 is connected to the first section nut 140 at the upper end of the inner steel pipe 110 via a hollow screw rod 5. This achieves a detachable connection between the extension section spiral pile core assembly 4 and the first section spiral pile core assembly 1. The outer steel pipe of the upper extension section spiral pile core assembly 4 is located between two adjacent extension section spiral pile core assemblies 4. The extension section nut 430 at the lower end of 420 is connected to the extension section nut 430 at the upper end of the outer steel pipe 420 in the lower extension section spiral pile core assembly 4 via a hollow screw 5. The extension section nut 430 at the lower end of the inner steel pipe 410 in the upper extension section spiral pile core assembly 4 is connected to the extension section nut 430 at the upper end of the inner steel pipe 410 in the lower extension section spiral pile core assembly 4 via a hollow screw 5, thus realizing the detachable connection of the two adjacent extension section spiral pile core assemblies 4. The inner steel pipe 410 and the outer steel pipe 420 of the extension section spiral pile core assembly 4 are driven by the inner and outer rotating drilling rig.

[0038] Example 7 like Figure 6 As shown, this embodiment is a further improvement on embodiment 6, as detailed below: The spacing of the helical blades 3 on the extended section helical pile core assembly 4 S H The diameter of the spiral blade 3 is 1 to 2 times that of the spiral core assembly 4. The number of spiral blades 3 on the extended section is 2 to 3, the inclination angle of the spiral blades 3 is 10° to 30°, and the diameter of the spiral blades 3 is... D H It is 3 to 4 times the outer diameter of the extended section of the spiral pile core assembly 4.

[0039] As a preferred option: the diameter of the helical blade 3 D H The spacing of the spiral blades is 875mm (equivalent to 3.5 times the outer diameter of the 420mm outer steel pipe of the extension section). S H The diameter was set to 1312.5mm (i.e. 1.5 times the diameter of the helical blade 3), and three helical blades 3 were installed, each with an inclination angle of 20°.

[0040] The outer steel pipe 420 and the inner steel pipe 410 of the extension section have anti-corrosion coatings on their surfaces. The rolling bearing 440 of the extension section has anti-corrosion coatings and lubrication coatings on its surface. The first section nut 140, the extension section nut 430 and the hollow screw 5 are made of alloy steel or surface-hardened steel. The first section nut 140, the extension section nut 430 and the hollow screw 5 have anti-corrosion coatings and surface hardening treatments on their surfaces.

[0041] Example 8 like Figure 5 , Figure 6 As shown, this embodiment is a further improvement on embodiment 6 or 7, as detailed below: The length of the first section of the helical pile core assembly 1 is 1m to 3m, and the outer diameter of the first section of the outer steel pipe 120 is... d 1 is 200mm~300mm, and the outer diameter of the inner steel pipe of the first section is 110. d 2 is 100mm~150mm; As a preferred embodiment, the length of the first section of the helical pile core assembly 1 is preferably 2.5m, and the outer diameter of the first section of the outer steel pipe 120 is... d 1. Preferably, the outer diameter of the inner steel pipe of the first section is 110 mm, which is 250 mm. d 2 is preferably 120mm; The length of the extended section helical pile core assembly 4 is 1m to 3m, and the outer diameter of the extended section helical pile core assembly 4 is... d 1 is 200mm~300mm, the outer diameter of the steel pipe in the extension section is 410. d 2 is 100mm to 150mm.

[0042] As a preferred embodiment, the length of the extended spiral pile core assembly 4 is preferably 2.5m, and the outer diameter of the extended outer steel pipe 420 is... d 1 is preferably 250mm, and the outer diameter of the steel pipe 410 in the extension section is 410mm. d 2 is preferably 120mm.

[0043] Example 9 like Figure 3 As shown, this embodiment is a further improvement on embodiment 6 or 7, as detailed below: The Reuleaux triangular drill bit 210 has three grouting holes 211 on its side, located on three concave sides, with an inner diameter of 3mm to 5mm.

[0044] like Figure 7 , Figure 8 As shown, a method for forming a Reuleaux triangular drilled grouting spiral pile core-strength composite square pile, based on the Reuleaux triangular drilled grouting spiral pile core-strength composite square pile forming device described in any of Examples 1 to 9, includes the following steps: In the first section of the spiral pile core assembly 1, the lower end of the first section of the inner steel pipe 110 is installed with a Reuleaux triangular drill bit assembly 2, and spiral blades 3 are welded around the outer wall of the first section of the outer steel pipe 120 in the first section of the spiral pile core assembly 1. First section of spiral pile core completed: First, align the Reuleaux triangular drill bit 210 with the construction point. Then, connect the drilling rig to the upper end of the first outer steel pipe 120 and the first inner steel pipe 110. At the same time, start the grouting equipment and supply grout into the grouting hole 211. During the operation, the drilling and grouting are carried out simultaneously until the designed pile foundation depth is reached. Assembly and pile driving of extension section helical pile core assembly 4: First, align the extension section spiral pile core assembly 4 coaxially with the first section spiral pile core assembly 1. Then, thread the lower end of the hollow screw 5 to the first nut 140 on the first section spiral pile core assembly 1, and thread the upper end of the hollow screw 5 to the extension nut 430 at the lower end of the extension section spiral pile core assembly 4. This allows the extension section spiral pile core assembly 4 to be attached to the first section spiral pile core assembly 1. Subsequently, connect the drilling rig to the upper ends of the extension section outer steel pipe 420 and the extension section inner steel pipe 410, and start the grouting equipment. During the operation, the drilling and grouting are carried out simultaneously until the designed pile foundation depth is reached. Then, another section of the extended spiral pile core assembly 4 is installed on the upper end of the extended spiral pile core assembly 4, and so on. At the same time, the grouting equipment is started, and the drilling and grouting are carried out simultaneously during the operation to reach the final designed pile foundation depth. The method of installing another section of the extended spiral pile core assembly 4 is as follows: the extended spiral pile core assembly 4 is coaxially aligned with the lower extended spiral pile core assembly 4, and then the lower end of the hollow screw 5 is threaded to the extension nut 430 of the lower extended spiral pile core assembly 4, and the upper end of the hollow screw 5 is threaded to the extension nut 430 at the lower end of the upper extended spiral pile core assembly 4, so as to realize the connection between two adjacent sections of the extended spiral pile core assembly 4. Then, the drilling rig is connected to the upper end of the extension outer steel pipe 420 and the extension inner steel pipe 410 in the upper extended spiral pile core assembly 4.

[0045] like Figure 7 , Figure 8 As shown: 1) In homogeneous soil layers such as clay, silt, and uniform sand, the Reuleaux triangular drill bit 210 and the auger blade 3 rotate synchronously at the same speed. In homogeneous soil layers, the rotation speed is typically between 20 and 60 revolutions per minute (RPM). This speed range ensures that the drill bit cuts the soil while the auger blade 3 effectively cuts and removes the soil, avoiding excessive wear on the equipment or excessive soil disturbance due to excessively high rotation speeds. Clay is relatively dense and has strong adhesion, so it is more suitable to work at low rotation speeds (such as 20-40 RPM) to prevent excessive soil disturbance and difficulty in soil removal. For looser silt and uniform sand, the rotation speed can be appropriately increased (such as 40-60 RPM). RPM (Rotating Per Millimeter) is used to improve work efficiency. Depending on the design of the drilling rig and pile core, the rotational speed must also consider the rated power and torque of the equipment to ensure continuous operation under stable loads. In projects requiring higher precision, a lower rotational speed may be necessary to ensure construction quality, while in efficiency-first scenarios, a higher rotational speed can accelerate the construction progress. During construction, the rotational speed can be adjusted appropriately based on feedback from the actual soil layers to find the optimal balance between work efficiency and construction quality. During construction, the drilling depth and soil conditions are continuously monitored to ensure the borehole reaches the designed depth. Simultaneously, grouting equipment is activated during the rotary drilling process to inject... Cement grout is evenly injected into the hole 211 to form a stable cement-soil layer. After the first section of the helical pile core assembly 1 reaches the design depth, the extension section of the helical pile core assembly 4 is installed on the upper end of the first section of the helical pile core assembly 1. The pile is formed by the double-axis spiral grouting process. After the first section of the extension section of the helical pile core assembly 4 reaches the design depth, another extension section of the helical pile core assembly 4 is installed on the upper end of the extension section of the helical pile core assembly 4, and so on, until the final pile foundation design depth is reached. Finally, the inspection and acceptance are carried out. The advantages of this installation method are that the cutting and soil removal process is stable, the equipment wear is small, the grouting process is easy to control, and it helps to form a uniform pile foundation structure.

[0046] 2) In hard soil or rock layers, such as rock, gravel and dense sand, the rotational speed of the Reuleaux triangular drill bit 210 is set higher than the rotational speed of the auger blade 3, with a speed difference range of 10 to 30 revolutions per minute (RPM). This difference range ensures that the drill bit has sufficient cutting speed to break hard geological layers, while the auger blade effectively discharges debris at a lower speed to prevent accumulation and blockage. Rock or extremely hard soil layers: For very hard rock layers, such as granite or basalt, the drill bit speed should be as high as possible, with a difference of 20 to 30 RPM, to ensure the drill bit's efficient cutting ability, while the auger blades keep a lower speed to gradually remove debris. Medium-hard gravel layers or dense sand: Under these conditions, the speed difference can be small, typically 10 to 20 RPM, to balance cutting efficiency and soil removal efficiency. During construction, actual geological conditions may change. It is recommended to adjust the speed difference in real time according to the cutting and soil removal effects to ensure the optimal working condition of the equipment. The speed difference also needs to be adjusted according to the torque and power distribution of the equipment to ensure that the drilling rig can operate stably and not cause mechanical failure due to excessive load; By setting a reasonable speed difference, cutting efficiency can be optimized, while reducing equipment wear and energy consumption, thus improving overall construction efficiency. In summary, in hard soil or rock layers, the reasonable speed difference between the Reuleaux triangular drill bit and the auger blade is typically 10 to 30 revolutions per minute, fine-tuned according to geological conditions and engineering requirements. At this speed, the high speed of the Reuleaux triangular drill bit (210) increases cutting efficiency, enabling rapid cutting of hard geological layers, but precise control of the grouting process is necessary to ensure quality. The slower speed of the auger blade (3) helps control the soil removal process, preventing excessive accumulation of cut material. During construction, the equipment is aligned with the predetermined pile position. After starting the drilling rig, the Reuleaux triangular drill bit 210 quickly cuts the soil or rock. Then, the grouting equipment is started to grout, and the grouting speed and pressure are adjusted to ensure that the grout can be evenly distributed around the hole. After the first section of the spiral pile core assembly 1 reaches the design depth, the extension section of the spiral pile core assembly 4 is installed on the upper end of the first section of the spiral pile core assembly 1. The pile is formed by continuing the double-axis spiral grouting process. After the first section of the extension section of the spiral pile core assembly 4 reaches the design depth, another extension section of the spiral pile core assembly 4 is installed on the upper end of the extension section of the spiral pile core assembly 4, and so on, until the final pile foundation design depth is reached. Finally, the inspection and acceptance are carried out.

[0047] 3) In soft soil layers (such as silt, loose sand, and aquifers), because the soil is easily cut and tends to accumulate, the rotational speed of the auger blade 3 usually needs to be higher than that of the Reuleaux triangular drill bit 210 to effectively remove the cut soil and prevent borehole blockage. The following is a reasonable range for the speed difference: 10 to 20 revolutions per minute (RPM). The reason is that in soft soil layers, this difference ensures that the auger blades can remove the cut soil at a higher speed while maintaining a stable cutting speed of the drill bit, preventing soil accumulation in the borehole and subsequent blockage. In extremely soft soil layers (such as silt), the speed difference can be slightly larger, typically 15 to 20 RPM, to ensure rapid removal of large amounts of loose soil and prevent blockage. In loose sand or aquifers, soil removal is relatively easy, and the speed difference can be slightly smaller, typically 10 to 15 RPM. RPM (Rotating Perm Motion) ensures efficient soil removal while maintaining effective drill bit cutting. In actual construction, the rotation speed difference should be adjusted appropriately based on the soil characteristics and soil removal effect to ensure optimal construction efficiency and quality. The rotation speed difference should be reasonably set according to the specific design and power characteristics of the drilling rig and auger blades to ensure the equipment operates under normal load and avoid mechanical failure. A reasonable rotation speed difference can optimize the construction process in soft soil layers, effectively removing cut soil while ensuring smooth drill bit cutting, avoiding blockage problems during construction, and improving construction efficiency. Soft soil layers are characterized by easy cutting, but require effective removal of the cut soil to prevent hole blockage. During construction, the equipment is first installed and aligned with the pile position, then the drilling rig is started. Due to the rapid rotation of the auger blades 3, the cut soil can be quickly removed, while the slower Reuleaux triangular drill bit 210 speed is sufficient to cut soft soil without causing excessive vibration. When the borehole reaches... After reaching the design depth, the grouting equipment is started, and cement grout is evenly injected through the grouting hole 211. The rapid rotation of the spiral blade 3 helps to evenly distribute the grout and reinforce the hole wall, forming a stable cement-soil structure. After the first spiral pile core assembly 1 reaches the design depth, the extension spiral pile core assembly 4 is installed on the upper end of the first spiral pile core assembly 1. The pile is then formed by the dual-axis spiral grouting process. After the first extension spiral pile core assembly 4 reaches the design depth, another extension spiral pile core assembly 4 is installed on the upper end of the extension spiral pile core assembly 4, and so on, until the final pile foundation design depth is reached. Finally, inspection and acceptance are carried out. After completion, quality inspection and load testing are conducted to ensure the integrity and bearing capacity of the pile foundation structure. The advantage of the spiral blade 3 rotating faster than the Reuleaux triangular drill bit 210 is that it can effectively prevent the pores in the soft soil layer from being blocked and ensure uniform grouting and good pile foundation quality.

[0048] In summary, the proposed Reuleaux triangle-drilled grouting spiral core reinforced composite square pile forming device achieves a comprehensive effect of efficient drilling and pile foundation reinforcement through the innovative Reuleaux triangle drill bit 210 design, spiral core, and grouting process. Utilizing the equal width characteristic and unique geometric structure of the Reuleaux triangle, it can form stable square holes, improving drilling accuracy and efficiency, and solving the hole deformation problem caused by traditional drill bits. Combined with the dual-axis spiral grouting process, it not only achieves effective soil removal and mixing but also significantly enhances the bearing capacity and stability of the pile foundation through the formed cement-soil structure. In particular, the design of the rolling bearings allows the inner and outer steel pipes to rotate independently, reducing construction friction and improving the durability of the equipment and the stability of construction.

[0049] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A Reuleaux triangular borehole-type grouting spiral pile core-strength composite square pile forming device, characterized in that, include: The first section of the spiral pile core assembly (1) and the Reuleaux triangular drill bit assembly (2) are provided. The first section of the spiral pile core assembly (1) includes an inner steel pipe (110) and an outer steel pipe (120) arranged coaxially. The upper and lower ends of the inner steel pipe (110) are rotatably connected to the inner wall of the outer steel pipe (120) via a first section rolling bearing (130). The outer wall of the outer steel pipe (120) is surrounded by spiral blades (3). The lower end of the inner steel pipe (110) is fixed to the Reuleaux triangular drill bit assembly (2). The Reuleaux triangular drill bit (210) of the Reuleaux triangular drill bit assembly (2) has a grouting hole (211) on its side.

2. The Reuleaux triangular drilling type grouting spiral pile core stiffening composite square pile forming device according to claim 1, characterized in that, The Reuleaux triangular drill bit assembly (2) includes: a Reuleaux triangular drill bit (210) and a grouting rod (220). The Reuleaux triangular drill bit (210) has a cutting edge (212) and a drilling face (213). The outlet end of the grouting rod (220) is connected to the inlet of the grouting hole (211) on the Reuleaux triangular drill bit (210). The Reuleaux triangular drill bit (210) is connected to the inner steel pipe (110) of the first section via a coupling (230) and the inlet end of the grouting rod (220).

3. A Reuleaux triangular drilling-type grouting spiral pile core-strength composite square pile forming device according to claim 1 or 2, characterized in that, The Reuleaux triangle side length of the Reuleaux triangle drill bit (210) a Not less than the diameter of the helical blade (3) D H The centroid P of the Reuleaux triangle is eccentrically offset r relative to the center O of the square hole by no more than 0.5a. The length of the cutting edge (212) on the Reuleaux triangle drill bit (210) is 2 / 3 to 3 / 4 of the side length of the Reuleaux triangle. The angle of the drilling facet (213) on the Reuleaux triangle drill bit (210) is 15° to 30°.

4. A Reuleaux triangular borehole-type grouting spiral pile core-strength composite square pile forming device according to claim 1 or 2, characterized in that, The spacing of the helical blades (3) on the first section of the helical pile core assembly (1) S H The diameter of the spiral blade (3) is 1 to 2 times that of the spiral blade (3). The number of spiral blades (3) on the first section of the spiral core assembly (1) is 2 to 3. The inclination angle of the spiral blades (3) is 10° to 30°. The diameter of the spiral blades (3) is 1 to 2 times that of the spiral blades (3). D H It is 3 to 4 times the outer diameter of the first section of the spiral pile core assembly (1).

5. The Reuleaux triangular borehole grouting spiral pile core stiffening composite square pile forming device according to claim 1, characterized in that, The Reuleaux triangular drill bit (210) is made of high-strength alloy steel or cemented carbide, and the spiral blade (3) is made of wear-resistant alloy steel or high-strength steel.

6. The Reuleaux triangular borehole grouting spiral pile core stiffening composite square pile forming device according to claim 1, characterized in that, The upper end of the first section of the spiral pile core assembly (1) is detachably coaxially connected to at least one extension section spiral pile core assembly (4). The extension section spiral pile core assembly (4) includes an inner steel pipe (410) and an outer steel pipe (420) arranged coaxially. The upper and lower ends of the inner steel pipe (410) are rotatably connected to the inner wall of the outer steel pipe (420) via rolling bearings (440). The outer wall of the outer steel pipe (420) is surrounded by spiral blades (3). The upper and lower ends of the outer steel pipe (420) of the extension section are respectively provided with extension section nuts (430), the upper and lower ends of the inner steel pipe (410) of the extension section are respectively provided with extension section nuts (430), the upper end of the first section outer steel pipe (120) is provided with a first section nut (140), the upper end of the first section inner steel pipe (110) is provided with a first section nut (140), the thread hole size of the extension section nut (430) is the same as the thread hole size of the first section nut (140), and the extension section outer steel pipe (4) located at the bottom is provided with an extension section nut (430). The extension section nut (430) at the lower end of the steel pipe (420) is connected to the first section nut (140) at the upper end of the first section outer steel pipe (120) via a hollow screw rod (5). The extension section nut (430) at the lower end of the extension section inner steel pipe (410) in the lowest extension section helical pile core assembly (4) is connected to the first section nut (140) at the upper end of the first section inner steel pipe (110) via a hollow screw rod (5). Between two adjacent extension section helical pile core assemblies (4), the extension section outer steel pipe (420) in the upper extension section helical pile core assembly (4) is connected to the first section nut (140) at the upper end of the first section inner steel pipe (110). The extension section nut (430) at the end is connected to the extension section nut (430) at the upper end of the outer steel pipe (420) of the extension section in the lower extension section spiral pile core assembly (4) via a hollow screw (5). The extension section nut (430) at the lower end of the inner steel pipe (410) of the upper extension section spiral pile core assembly (4) is connected to the extension section nut (430) at the upper end of the inner steel pipe (410) of the lower extension section spiral pile core assembly (4) via a hollow screw (5).

7. The Reuleaux triangular borehole grouting spiral pile core stiffening composite square pile forming device according to claim 6, characterized in that, The spacing of the helical blades (3) on the extended section helical pile core assembly (4) S H The diameter of the spiral blade (3) is 1 to 2 times the diameter of the spiral blade (3). The number of spiral blades (3) on the extended spiral core assembly (4) is 2 to 3. The inclination angle of the spiral blades (3) is 10° to 30°. The diameter of the spiral blades (3) is 1 to 2 times the diameter of the spiral blades (3). D H The outer diameter of the extended section spiral pile core assembly (4) is 3 to 4 times.

8. A Reuleaux triangular drilling-type grouting spiral pile core-strength composite square pile forming device according to claim 6 or 7, characterized in that, The length of the first section of the helical pile core assembly (1) is 1m to 3m, and the outer diameter of the first section of the outer steel pipe (120) is... d 1 is 200mm~300mm, the outer diameter of the inner steel pipe (110) of the first section. d 2 is 100mm~150mm, the length of the extended section spiral pile core assembly (4) is 1m~3m, and the outer diameter of the extended section outer steel pipe (420) is... d 1 is 200mm to 300mm, and the outer diameter of the steel pipe (410) in the extended section is... d 2 is 100mm to 150mm.

9. A method for constructing a Reuleaux triangular drilled grouting spiral pile core-strength composite square pile, characterized in that, The pile-forming device for Reuleaux triangular drilling grouting spiral pile core stiffening composite square pile as described in any one of claims 1 to 8 includes the following steps: First, align the Reuleaux triangular drill bit (210) with the construction point. Then, connect the drilling rig to the upper end of the first outer steel pipe (120) and the first inner steel pipe (110). At the same time, start the grouting equipment and supply grout into the grouting hole (211). During the operation, the drilling and grouting are carried out simultaneously to reach the designed pile foundation depth.

10. The method for constructing a Reuleaux triangular drilled grouting spiral pile core-reinforced composite square pile according to claim 9, characterized in that, If the first section of the spiral pile core assembly (1) and the Reuleaux triangular drill bit assembly (2) fail to reach the final designed pile foundation depth, then firstly, align the extended section of the spiral pile core assembly (4) coaxially with the first section of the spiral pile core assembly (1), then thread the lower end of the hollow screw (5) to the first section nut (140) on the first section of the spiral pile core assembly (1), and thread the upper end of the hollow screw (5) to the extended section nut (430) at the lower end of the extended section of the spiral pile core assembly (4) to achieve the final design pile foundation depth. The first section of the spiral pile core assembly (1) is connected to the previous section of the extended spiral pile core assembly (4). Then the drilling rig is connected to the upper end of the outer steel pipe (420) and the inner steel pipe (410) of the extended section. At the same time, the grouting equipment is started. During the operation, the spiraling and grouting are carried out simultaneously until the designed pile foundation depth is reached. Then another section of the extended spiral pile core assembly (4) is installed on the upper end of the extended spiral pile core assembly (4). This process is repeated. At the same time, the grouting equipment is started. During the operation, the spiraling and grouting are carried out simultaneously until the final designed pile foundation depth is reached.

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