A concrete cast-in-place pile with an enlarged diameter screw thread pile section, a drill bit device for pile formation, and a pile formation method

Abstract

This invention relates to a cast-in-place concrete pile with an enlarged-diameter threaded pile segment, a drilling bit device for pile formation, and a pile formation method. The cast-in-place concrete pile with an enlarged-diameter threaded pile segment includes a concrete main pile, which consists of a pile bottom, a pile body, and a pile top. The pile bottom is an enlarged head structure formed by extending the concrete main pile outwards through re-compacting concrete. It includes a threaded pile segment and at least one enlarged-diameter threaded pile segment. The threaded pile segment has an integrally formed, outwardly protruding, spirally coiled threaded tooth on the outer edge of the concrete main pile. The enlarged-diameter threaded pile segment is formed by extending a portion of the threaded pile segment outwards through re-compacting concrete, resulting in an outer diameter larger than that of the threaded pile segment. The threaded pile segment and the enlarged-diameter threaded pile segment are located in the pile body and / or the pile top. This invention is applicable to fill, cohesive soil, silt, sand, and other soil layers, enabling one-time pile formation and possessing high bearing capacity.

Description

Technical Field

[0001] The invention belongs to the field of foundation pile construction of building construction, and specifically relates to a concrete cast-in-place pile with an enlarged diameter screw thread pile section, a drill bit device for pile formation, and a pile formation method. Background Art

[0002] In the existing construction of building pile foundations, for geological conditions such as clay, silt, sand and fill, most of them first use cement slurry to reinforce the soil around the pile, and then construct rigid concrete piles to obtain a higher bearing capacity. However, there are also serious shortcomings: first, the same pile needs to be constructed twice, which is high in construction cost; second, cement slurry is injected into the ground, which pollutes the groundwater environment; third, there are many human factors in the reinforcement of the original soil layer, and at the same time, it is affected by uneven strata, resulting in large differences in reinforcement results; fourth, the cost of pile construction is high; fifth, this type of pile is mainly based on side resistance, and the soil stress at the bottom of the pile is not fully exerted. Summary of the invention

[0003] In view of the above-mentioned technical problems, the present invention proposes a concrete bored pile, a pile drill device and a pile construction method which are suitable for fill, clay, silt, sand and other soil layers, can be formed into piles in one go and have high bearing capacity, and have an enlarged diameter threaded pile section.

[0004] The technical scheme adopted by the invention is: a concrete cast-in-place pile with an enlarged diameter screw thread pile section, comprising a concrete main pile, wherein the concrete main pile is composed of a pile bottom, a pile body and a pile top; the shape of the pile bottom is an enlarged head structure formed by extending the concrete main pile to the surroundings through composite compaction of concrete; a screw thread pile section and at least one section of enlarged diameter screw thread pile section are provided, wherein the screw thread pile section is an outwardly protruding spirally coiled screw thread with an integral structure formed on the outer edge of the concrete main pile; the enlarged diameter screw thread pile section is an enlarged diameter screw thread pile section whose outer edge outer diameter is larger than the outer edge outer diameter of the screw thread pile section formed by extending part of the screw thread pile section to the surroundings through composite compaction of concrete; the screw thread section is a trapezoidal structure; the screw thread pile section is arranged on the pile body and / or the pile top; the enlarged diameter screw thread pile section is arranged on the pile body and / or the pile top.

[0005] Furthermore, the above-mentioned cast-in-place concrete pile with an enlarged diameter screw thread pile section is provided with a column pile section, and the column pile section is arranged at the pile body and / or the pile top.

[0006] Furthermore, the above-mentioned cast-in-place concrete pile with an enlarged diameter screw thread pile section is provided with an enlarged diameter column pile section, wherein the enlarged diameter column pile section is formed by extending the formed column pile section to the surroundings through the re-extruded concrete to form an enlarged diameter column pile section with an outer edge outer diameter greater than the outer edge outer diameter of the column pile section, and the enlarged diameter column pile section is arranged on the pile body and / or the pile top.

[0007] A drill bit device for concrete cast-in-place pile with an enlarged diameter screw thread pile section comprises a joint, a spiral blade I, a core tube I, a core tube II, a spiral blade II, a cutting tooth and a drill tip device, wherein the drill tip device comprises a double-ear plate seat I, a double-ear plate seat II, an axis I, a drill tip and a door, the double-ear plate seat I and the double-ear plate seat II are symmetrically fixed to the lower end of the core tube II, and their inner gears are arranged in a line, the upper end of the drill tip is made into a U-shaped structure, one end of the drill tip U-shaped structure is fixed to the double-ear plate seat II through the axis I, and the other end of the drill tip U-shaped structure is movably matched with the double-ear plate seat I, the door is fixed to the middle and upper part of the drill tip, the outer edge of the door coincides with the outer edge of the lower end face of the core tube II, and the drill tip and the door rotate around the axis I together; the outer edge of the outer surface of the core tube II after being wound with the spiral blade II forms a frustum, and the lower end face of the core tube II forms an angle β with the horizontal plane, β=0-30°; the lower end face of the double-ear plate seat II A limit contact point is provided on the upper surface for limiting the door from swinging open to a maximum angle α, wherein the angle α is the angle between the upper plane of the door and the horizontal plane, and α=10-40°; a rotating slider mechanism is provided, wherein the rotating slider mechanism is arranged in the inner cavity of the drill device, and is composed of an articulated seat, an axis II, a cylinder device, an axis III, a rotating slider, an axis IV and a fixed seat, wherein the articulated seat is fixed on the inner wall of the core tube I, the fixed seat is fixed on the lower end of the core tube I, the middle part of the rotating slider is connected to the fixed seat through the axis IV, the rotating slider rotates around the axis IV, the rotating slider is arranged at the lower end of the spiral blade I, and on the spiral line of the spiral blade I, wherein the spiral blade I and the core tube I are provided with a notch for the rotating slider to rotate through, the other end of the rotating slider is connected to the cylinder device through the axis III, and the other end of the cylinder device is hinged to the articulated seat through the axis II; the working end of the rotating slider is a trapezoidal structure.

[0008] Furthermore, in the above-mentioned drill bit device for concrete bored piles with an enlarged diameter screw thread pile section, the outer edge of the outer surface of the core tube II after the spiral blade II is wrapped around it forms a column, the fixed seat is fixed to the lower end of the core tube II, and the rotating slider is arranged above the cutting teeth at the lower end of the spiral blade II. Here, the spiral blade II and the core tube II are provided with a notch for the rotating slider to rotate through, and the rotating slider and the spiral blade II are on the same spiral line.

[0009] Furthermore, the above-mentioned drill bit device for concrete bored piles with an enlarged diameter threaded pile section, the cylinder device includes a cylinder, an outer sleeve, a sliding rod, a hinge, a nut, a spring seat, a push rod and a preloaded compression spring; one end of the push rod is connected to the piston rod of the cylinder, and the other end is fixed to the nut, and the preloaded compression spring and the spring seat pass through the middle, one end of the sliding rod is connected to the outer diameter of the spring seat, and the other end is fixed to the hinge, one end of the outer sleeve is connected to the outer diameter of the cylinder, and the inner diameter of the other end is sealed and slidably matched with the outer diameter of one end of the sliding rod, the rotating slider is connected to the hinge of the cylinder device through shaft III, and the cylinder device is connected to the hinge seat through the cylinder and shaft II.

[0010] Furthermore, in the above-mentioned drill bit device for concrete bored piles with an enlarged diameter threaded pile section, the preload force of the preloaded compression spring is equal to the maximum thrust value of the oil cylinder.

[0011] Furthermore, in the above-mentioned drill bit device for forming a concrete cast-in-place pile with an enlarged diameter threaded pile section, β=5-25°; α=15-30°.

[0012] Furthermore, in the above-mentioned drill bit device for concrete cast-in-place piles with an enlarged diameter threaded pile section, the coupling, core tube I and core tube II are coaxially fixed in sequence to form an integral structure, a channel for concrete to pass through is provided inside, spiral blades I are wound around the outer surfaces of the coupling and core tube I, spiral blades II are wound around the outer surface of core tube II, the upper end surface of spiral blade II is correspondingly connected to the lower end surface of spiral blade I, and cutting teeth are provided at the lower end of spiral blade II.

[0013] Furthermore, the above-mentioned drill bit device for concrete cast-in-place piles with an enlarged diameter threaded pile section has two spiral blades II, and the two spiral blades II are symmetrically installed on the outer surface of the core tube II, and the upper end surface of one spiral blade II is correspondingly connected to the lower end surface of the spiral blade I.

[0014] Furthermore, in the above-mentioned drill bit device for forming a concrete bored pile with an enlarged diameter threaded pile section, the outer shape of the core tube II is a frustum, or a frustum at the upper end and a column at the lower end.

[0015] Furthermore, in the above-mentioned drill bit device for concrete cast-in-place piles with an enlarged diameter screw pile section, when the door is rotated to the maximum position, an angle δ is formed between the lower end surface of the core tube II and the upper plane of the door, δ=35~50°.

[0016] A method for forming a concrete cast-in-place pile with an enlarged diameter screw thread pile section, using the above-mentioned drill bit device, comprises the following steps:

[0017] 1) Level the site, lay out the lines according to the drawings, determine the pile positions, and mark them;

[0018] 2) The drill bit device is assembled through the drill rod and the pile driver power head, the rotary slider mechanism control system and the concrete pumping device, and the pile driver is started to drive the drill bit with the rotary slider in a fully retracted state to rotate and squeeze the soil to form a cylindrical hole until the designed depth of the pile hole is reached;

[0019] 3) In the process of matching the drilling and pressure pouring, the formation of each pile section is realized:

[0020] 3.1) Formation of the enlarged head structure at the bottom of the pile: The rotating slider in the drill bit device is in a fully retracted state, the drill is lifted and concrete is poured. When the bottom end of the drill bit device is 1.5-2m high from the bottom of the pile, the lifting of the drill and the pouring are stopped, and the rotating drill bit device is released downward again to drill. The pressure concrete in the pile hole pushes the door to rotate upward to close the discharge port channel. At the same time, the lower part of the drill bit is used to squeeze the concrete in the pile hole to perform double compaction of the concrete. The rock and soil wall of the pile hole is squeezed and expanded by the double-extruded concrete to form an expanded rock and soil aperture. Most of the concrete in the pile hole remains in the inner cavity of the rock and soil hole of the expanded part. It is squeezed and drilled to the bottom of the pile, rotated in place for 1 minute, and the pile bottom soil and concrete are fully mixed to fully compact the rock and soil hole wall at the bottom of the pile. Then the drill tool is lifted and the concrete is pumped and poured. The injected concrete is integrated with the original concrete in the pile hole, and the mixed soil and concrete mixture is pressed on the bottom of the pile. The drill is lifted and poured to a height of 1.5-2m from the bottom of the pile to complete the construction of the enlarged head structure at the bottom of the pile.

[0021] 3.2) Formation of column pile section: Keep the rotary slide in the drill device in a fully retracted state, lift the drill bit and pump concrete to form the column pile section;

[0022] 3.3) Formation of screw-thread pile section: In the process of lifting the drill bit device rotating in the drilling direction and pumping concrete, the rotating slider mechanism control system is used to rotate the rotating slider to extend the core tube and spiral blades and squeeze into the rock and soil of the pile hole wall. At the same time, the drilling tool speed is adjusted to ensure that the screw groove formed by the rotating slider in the rock and soil of the pile hole wall rises in a spiral line to meet the requirements of the designed pitch. The pressure concrete in the foundation pile hole is immediately filled into the screw groove and poured together with the concrete main pile hole to form a spirally coiled screw tooth that is integrated with the outer edge of the concrete main pile and protrudes outward, forming a screw-thread pile section;

[0023] 3.4) Formation of enlarged diameter screw thread pile section: lift the drill and pour the screw thread pile section to a certain designed height, stop lifting the drill and pouring, start the rotary slider mechanism control system, retract the rotary slider, and release the drill bit device rotating in the drilling direction downward again. Under the action of the pressure concrete in the screw thread pile hole, the door closes the discharge port, and the lower part of the drill bit performs re-extrusion of the concrete in the screw thread pile section. The re-extruded concrete is used to squeeze the rock and soil in contact with the hole wall, and the rock and soil pore diameter is expanded. Most of the squeezed concrete remains in the squeezed and expanded hole cavity. After the extrusion and expansion drilling reaches the designed depth, lift the drill and pressurize the concrete. The poured concrete is integrated with the concrete retained in the hole. Lift the drill and pressurize to the designed height to form an enlarged diameter screw thread pile section;

[0024] 3.5) Formation of enlarged diameter column pile section: lift the drill and pressure-grout the column pile section to the designed height, stop lifting the drill and pressure-grouting, release the drill bit device rotating in the drilling direction downward again, the pressurized concrete in the foundation pile hole pushes the door to close the discharge port, the lower part of the drill bit performs re-extrusion drilling of the concrete in the column pile section, and the re-extruded concrete squeezes the rock and soil wall of the pile hole to form an enlarged diameter rock and soil pore. Most of the squeezed concrete remains in the inner cavity of the enlarged diameter rock and soil. After squeezing and drilling to the designed depth, lift the drill and pressure-grout the concrete again. The poured concrete is integrated with the concrete retained in the hole, lift the drill and pressure-grout to the designed height to form an enlarged diameter column pile section.

[0025] 4) Place the prefabricated steel cage or components into the poured pile hole to meet the design elevation.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section, which is used in soft soil layers such as fill, clay, silt, sand, etc., making full use of the large compressibility of the soil. According to the distribution of the soil around the pile, the pile section can be reasonably selected and optimized to meet the requirements of the maximum bearing capacity, and the resulting pile has a very strong pull-out resistance.

[0028] 2. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section, the loose soil at the pile bottom is reasonably processed, and an enlarged head is arranged at the pile bottom, which greatly improves the end resistance value of the pile.

[0029] 3. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section. The pile body section is provided with a screw thread pile section. The pouring of the screw thread and the pouring of the foundation pile are completed in one piece, and the pile strength is good. The soil between the screw threads is not disturbed, and the effective circumferential area of ​​the pile body of the screw thread section pile is reasonably increased. Under the condition of the same bearing capacity, compared with a solid concrete pile, the pile material is saved.

[0030] 4. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section. The enlarged diameter column pile section and the screw thread pile section are both achieved by re-squeezing the concrete in the pile hole. Firstly, the pile body concrete is compacted, and secondly, new end resistance is added, while also increasing the side resistance of the pile.

[0031] 5. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section, and the pile top section can be constructed with an enlarged diameter pile section, which is beneficial to the application of composite foundations.

[0032] 6. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section. The depth and size of the screw thread of the pile section can be adjusted according to engineering geological conditions and design requirements. The same pile can be automatically adjusted according to the size of the rock and soil compressibility, eliminating the drill jamming phenomenon caused by inaccurate geological surveys.

[0033] 7. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section, which has no mud, no vibration, no noise and less residual soil discharge during construction.

[0034] 8. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section, which can be completed by a single machine, has reliable pile quality, is easy to operate, has strong controllability, and has high construction efficiency.

[0035] 9. The present invention creates a concrete cast-in-place pile with an enlarged diameter screw thread pile section, which has low equipment investment and can be upgraded and transformed with existing equipment, thus giving full play to and utilizing existing equipment resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The present invention is a structural schematic diagram of a pile-forming drill bit device in which a core tube II is a combination of a frustum-shaped body and a short column, and the outer edge of a spiral blade II is a columnar body.

[0037] Figure 2 The present invention is a structural schematic diagram of a pile-forming drill bit device in which a core tube II is in a frustum shape and an outer edge of a spiral blade II is in a frustum shape.

[0038] Figure 3 The present invention is a schematic diagram of the structure of a rotating slider mechanism in which the rotating slider is arranged at the lower end of the spiral blade I.

[0039] Figure 4 The present invention is a schematic diagram of the structure of a rotating slider mechanism in which the rotating slider is arranged at the lower end of the spiral blade II.

[0040] Figure 5 It is a schematic diagram of the drill tip device structure (with the discharge port open).

[0041] Figure 6 It is a schematic diagram of the drill tip device structure (discharge port closed).

[0042] Figure 7 yes Figure 6 Middle AA section view.

[0043] Figure 8 It is a schematic diagram of the structure of the cylinder device.

[0044] Fig. 9 It is a schematic diagram of the structure of spiral blade I (without notch).

[0045] Fig.10 It is a schematic diagram of the structure of spiral blade I (with a notch).

[0046] Fig.11 It is a schematic diagram of the structure of spiral blade II (without notch).

[0047] Fig.12 It is a schematic diagram of the structure of spiral blade II (with a notch).

[0048] Fig.13 The present invention is a schematic diagram of the structure of the first concrete cast-in-place pile with an enlarged diameter screw thread pile section.

[0049] Fig.14 The present invention is a schematic diagram of the structure of a second type of concrete cast-in-place pile with an enlarged diameter screw thread pile section.

[0050] Fig.15 The present invention is a schematic diagram of the structure of a third type of concrete cast-in-place pile with an enlarged diameter screw thread pile section.

[0051] Fig.16 The present invention is a schematic diagram of the structure of a fourth type of cast-in-place concrete pile with an enlarged diameter screw thread pile section.

[0052] Fig.17 The present invention is a schematic diagram of the structure of a fifth type of cast-in-place concrete pile with an enlarged diameter screw thread pile section.

[0053] Fig.18 The present invention is a schematic diagram of the structure of a sixth type of cast-in-place concrete pile with an enlarged diameter screw thread pile section.

[0054] Fig.19 This is a schematic diagram of the door of the drill bit being closed under force when the drill tool moves downward during the drilling of the bottom section of the multi-compacted pile during pile construction.

[0055] Fig. 20 This is a schematic diagram of the process of pile formation, in which the bottom end of the pile is squeezed and expanded during grouting, and the drill bit is rotated, lifted up and pressure poured.

[0056] Fig.21 This is a schematic diagram of the process of pile formation in which the drill bit is rotated, lifted and pressed to form the pile thread during grouting.

[0057] Fig. 22 It is a schematic diagram of the enlarged diameter screw thread pile section formed during the drilling of the double-dense screw thread pile section during pile forming.

[0058] Fig.23 This is a schematic diagram of the process of lifting the drill bit upward and pressurizing during pouring to form the threaded threads of the top section of the pile during pile forming. DETAILED DESCRIPTION

[0059] Example 1

[0060] like Figure 1-Figure 12 As shown, a drill bit device for concrete cast-in-place piles with an enlarged diameter threaded pile section comprises a coupling 1, a spiral blade Ⅰ2, a core tube Ⅰ3, a core tube Ⅱ4, a spiral blade Ⅱ5, a cutting tooth 6, a drill tip device 7 and a rotating slider mechanism 8.

[0061] The joint 1, the core tube I3 and the core tube II4 are coaxially fixed in sequence to form an integral structure, and a channel for concrete to pass through is provided inside. The outer surfaces of the joint 1 and the core tube I3 are wound with spiral blades I2, and the outer surface of the core tube II4 is wound with spiral blades II5. The upper end surface of the spiral blade II5 is correspondingly connected to the lower end surface of the spiral blade I2, and the lower end of the spiral blade II5 is provided with cutting teeth 6. The drill tip device 7 is provided at the lower end of the core tube II4.

[0062] In one embodiment, the pile drilling device is a single-lead structure, that is, Figure 1 As shown, a spiral blade II5 is provided, the upper end surface of the spiral blade II5 is correspondingly connected to the lower end surface of the spiral blade I2, and the lower end of the spiral blade II5 is provided with a cutting tooth 6.

[0063] In one embodiment, the pile drilling device is a double-lead structure, that is, Figure 2 As shown, two spiral blades II5 are provided, and the two spiral blades II5 are symmetrically installed, and the upper end surface of one spiral blade II5 is correspondingly connected to the lower end surface of the spiral blade I2.

[0064] In one embodiment, Figure 1 As shown, the outer shape of the core tube II 4 is a frustum-shaped upper end and a columnar lower end.

[0065] In one embodiment, Figure 2 As shown, the outer shape of the core tube II 4 is a frustum.

[0066] In one embodiment, Figure 2 As shown, after the spiral blade II 5 is wound around the core tube II 4, the overall outer edge of the spiral blade II 5 is in a frustum shape.

[0067] In one embodiment, Figure 1 As shown, after the spiral blade II5 is wound around the core tube II4, the overall outer edge of the spiral blade II5 is cylindrical.

[0068] The drill tip device 7 comprises a double-ear plate seat I7-1, a double-ear plate seat II7-2, a shaft I7-3, a drill tip 7-4 and a door 7-5. The double-ear plate seat I7-1 and the double-ear plate seat II7-2 are symmetrically fixed to the lower end of the core tube II4, and their inner gears are arranged in a line, so that the drill tip 7-4 can slide through. The upper end of the drill tip 7-4 is made into a U-shaped structure. One side of the double-ear plate seat II7-2 and the upper end U-shaped structure of the drill tip 7-4 are respectively provided with holes for the shaft I7-3 to pass through. One end of the U-shaped structure of the drill tip 7-4 is fixed to the double-ear plate seat II7-2 through the shaft I7-3, and the other end of the U-shaped structure of the drill tip 7-4 is movably matched with the double-ear plate seat I7-1. The door 7-5 is fixed to the middle and upper part of the drill tip 7-4, and the outer edge of the door 7-5 coincides with the outer edge of the lower end surface of the core tube II4. The drill tip 7-4 and the door 7-5 rotate around the shaft I7-3 together.

[0069] The lower end surface of the core tube II 4 forms an angle β with the horizontal plane, β=0-30°. Preferably, β=5-25°.

[0070] When the door 7-5 rotates downward to the limit position through the shaft I7-3, the point where the edge of the door 7-5 near the double-ear plate seat II7-2 contacts the bottom end of the double-ear plate seat II7-2 is set as the limit contact point D, and the limit contact point D limits the door 7-5 to rotate to the maximum angle α. The door 7-5 is limited by the limit contact point D, thereby limiting the drill tip 7-4 from continuing to rotate downward, and the α is the angle between the upper plane of the door 7-5 and the horizontal plane, α = 10-40°. Preferably, α = 15-30°.

[0071] The drill tip 7-4 rotates together with the door 7-5 around the axis I7-3: the limit position of the upward rotation is the junction of the upper plane of the door 7-5 and the lower end surface of the core tube II4, closing the discharge port of the concrete channel in the inner cavity of the drill bit, and at the same time, the other side of the upper U-shaped structure of the drill tip 7-4 is completely matched with the inner stop of the double-ear plate seat I7-1; the limit position of the downward rotation is the point where the edge of the door 7-5 near the side of the double-ear plate seat II7-2 contacts the bottom end of the double-ear plate seat II7-2, which is set as the limit contact point D, and the door 7-5 is limited by the limit contact point D, thereby limiting the drill tip 7-4 from continuing to rotate downward. At this time, the door 7-5 opens the discharge port of the drill bit, and the upper plane of the door 7-5 forms an angle α with the horizontal plane.

[0072] In one embodiment, more preferably, when the door 7-5 is rotated to the maximum position through the axis I7-3, an angle δ is formed between the lower end surface of the core tube II4 and the upper plane of the door 7-5, and δ=35~50°.

[0073] In one embodiment, Fig. 9 As shown, there is no notch on the spiral blade Ⅰ2.

[0074] In one embodiment, Fig.10 As shown, the spiral blade Ⅰ2 has a notch Ⅰ2-1.

[0075] In one embodiment, Fig.11 As shown, spiral blade II 5 has no notch.

[0076] In one embodiment, Fig.12 As shown, spiral blade II5 has a notch II5-1.

[0077] The rotating slider mechanism 8 is arranged in the inner cavity of the drill bit device, and is composed of an articulated seat 8-1, shaft II 8-2, a cylinder device 8-3, shaft III 8-4, a rotating slider 8-5, shaft IV 8-6 and a fixed seat 8-7.

[0078] In one embodiment, when the spiral blade II 5 is wound around the core tube II 4 and the outer edge of the spiral blade II 5 is in a frustum shape, the installation method of the rotating slider mechanism 8 is as follows: Figure 3 As shown, the rotary slider is arranged at the lower end of the spiral blade Ⅰ2. The hinge seat 8-1 is fixed on the inner wall of the core tube Ⅰ3, the fixed seat 8-7 is fixed on the lower end of the core tube Ⅰ3, the middle part of the rotary slider 8-5 is connected with the fixed seat 8-7 through the shaft IV8-6, and the rotary slider 8-5 rotates around the shaft IV8-6. The rotary slider 8-5 is arranged at the lower end of the spiral blade Ⅰ2 and on the spiral line of the spiral blade Ⅰ2. The spiral blade Ⅰ2 and the core tube Ⅰ3 here are provided with a notch for the rotary slider 8-5 to rotate through. The other end of the rotary slider 8-5 is connected to the cylinder device 8-3 through the shaft III8-4, and the other end of the cylinder device 8-3 is hinged to the hinge seat 8-1 through the shaft II8-2; the working end 8-5-1 of the rotary slider 8-5 is a trapezoidal structure.

[0079] In one embodiment, when the spiral blade II 5 is wound around the core tube II 4 and the outer edge of the spiral blade II 5 is cylindrical, the installation method of the rotating slider mechanism 8 is as follows: Figure 4 As shown, the rotary slider is arranged at the lower end of the spiral blade II 5. The hinge seat 8-1 is fixed on the inner wall of the core tube I 3, the fixed seat 8-7 is fixed on the lower end of the core tube II 4, the middle part of the rotary slider 8-5 is connected with the fixed seat 8-7 through the shaft IV 8-6, the rotary slider 8-5 rotates around the shaft IV 8-6, the rotary slider 8-5 is arranged above the cutting teeth 6 at the lower end of the spiral blade II 5, the rotary slider 8-5 and the spiral blade II 5 are on the same spiral line, the spiral blade II 5 and the core tube II 4 are provided with a notch for the rotary slider 8-5 to rotate through, the other end of the rotary slider 8-5 is connected to the cylinder device 8-3 through the shaft III 8-4, and the other end of the cylinder device 8-3 is hinged to the hinge seat 8-1 through the shaft II 8-2; the working end 8-5-1 of the rotary slider 8-5 is a trapezoidal structure.

[0080] The oil cylinder device 8-3 includes an oil cylinder 8-3-1, a jacket 8-3-2, a slide rod 8-3-3, a hinge 8-3-4, a nut 8-3-5, a spring seat 8-3-6, a push rod 8-3-7 and a preloaded compression spring 8-3-8; one end of the push rod 8-3-7 is connected to the piston rod of the oil cylinder 8-3-1, and the other end is fixed to the nut 8-3-5, and the preloaded compression spring 8-3-8 and the spring seat 8-3-6 are passed through the slide rod 8-3- One end of 3 is connected to the outer diameter of spring seat 8-3-6, and the other end is fixed to hinge 8-3-4, one end of outer sleeve 8-3-2 is connected to the outer diameter of cylinder 8-3-1, and the inner diameter of the other end is sealed and slidably matched with the outer diameter of one end of slide rod 8-3-3, the rotating slider 8-5 is connected to the hinge 8-3-4 of cylinder device 8-3 through shaft III 8-4, and cylinder device 8-3 is connected to hinge seat 8-1 through cylinder 8-3-1 and shaft II 8-2.

[0081] Preferably, the preload force of the preload compression spring 8-3-8 is equal to the maximum thrust value of the cylinder 8-3-1.

[0082] The working principle of the rotary slider mechanism created by the present invention is as follows: pressure oil enters the rodless chamber of the oil cylinder 8-3-1, and the piston rod extends to drive the push rod 8-3-7, the preloaded compression spring 8-3-8, the spring seat 8-3-6, the slide bar 8-3-3 and the hinge 8-3-4 to extend, thereby pushing the inner end of the rotary slider 8-5 to rotate downward around the axis IV8-6, causing the outer end of the rotary slider 8-5 to rotate upward around the axis IV8-6; pressure oil enters the rod chamber of the oil cylinder 8-3-1, and the piston rod is retracted, and the inner end of the rotary slider 8-5 is pulled to rotate upward around the axis IV8-6 through the push rod 8-3-7, the spring seat 8-3-6, the slide bar 8-3-3 and the hinge 8-3-4, driving the outer end of the rotary slider 8-5 to rotate downward around the axis IV8-6, and the rotary slider 8-5 is retracted. When the extended rotary slider 8-5 squeezes the rock and soil of the pile hole wall to form a groove, the reaction force on the rotary slider 8-5 is different due to the different compressibility of the rock and soil. The less compressible the rock and soil, the greater the reaction force on the rotary slider 8-5. The large reaction force pushes the outer end of the rotary slider 8-5 to rotate downward around the axis IV 8-6, driving the inner end of the rotary slider 8-5 to rotate upward, and applying force to the preload compression spring 8-3-8 through the hinge 8-3-4, the slide rod 8-3-3, and the spring seat 8-3-6 to compress the preload compression spring 8-3-8, and the push rod 8-3-7 and the nut 8-3-5 The fixed end enters the B cavity of the slide bar 8-3-3, so that the moving slide bar 8-5 is squeezed into a small groove or does not form a groove when passing through the rock and soil layer of the pile hole wall with low compressibility; after passing through this section of rock and soil layer with low compressibility, as the compressibility of the rock and soil increases, the compressed pre-tightening compression spring 8-3-8 releases energy, pushing the spring seat 8-3-6 to move, and pushing the inner end of the rotating slide bar 8-5 to rotate downward around the axis IV8-6 through the slide bar 8-3-3 and the hinge 8-3-4, driving the outer end of the rotating slide bar 8-5 to rotate upward, thereby realizing the rotating slide bar 8-5 rotating outward and extending to form a large groove.

[0083] The present invention creates a closing principle of the discharge port of the drill bit device in the concrete in the pile hole: when the drill is lifted and concrete is poured, the door 7-5 in the drill bit is opened and forms an angle α with the horizontal plane, opening the concrete discharge port channel to ensure the pouring flow rate of the concrete, and by setting the lower end face of the drill bit core tube II4 to an upwardly inclined angle β, the cross-sectional area of ​​the drill bit discharge port is increased to achieve a reasonable reduction in the angle α, usually taking α=15~30°. When the drill tool moves downward to squeeze the concrete in the pile hole, the pressure concrete in the pile hole exerts an upward force on the door 7-5. The effective area of ​​the door 7-5 subjected to the force increases as the angle α decreases, thereby reducing the speed at which the drill tip 7-4 and the door 7-5 descend along with the drill tool until the downward movement stops. The drill tool continues to move downward, and the pressure concrete in the pile hole forces the drill tip 7-4 to drive the door 7-5 to rotate upward around the pin shaft I7-3 to close the discharge port, thereby cutting off the passage between the concrete in the pile hole and the concrete in the inner cavity of the drill tool, limiting the inflow of the concrete in the pile hole into the inner cavity of the drill tool, and improving the effective utilization rate of the re-extruded concrete in the pile hole.

[0084] Example 2

[0085] (I) Structure of cast-in-place concrete piles with enlarged diameter screw pile sections

[0086] like Figure 13-Figure 18 As shown, a concrete cast-in-place pile with an enlarged diameter threaded pile section includes a concrete main pile 10, wherein the concrete main pile 10 is composed of a pile bottom 11, a pile body 12 and a pile top 13.

[0087] The pile bottom 11 is in the shape of an enlarged head structure 14 formed by extending the concrete main pile 10 to all sides through the composite compaction concrete.

[0088] A screw pile section 15 is provided, wherein the screw pile section 15 is an outwardly protruding spirally wound screw thread 17 of an integral structure formed on the outer edge of the concrete main pile 10; the cross section of the screw thread 17 is a trapezoidal structure; the screw pile section 15 is arranged on the pile body 12 and / or the pile top 13.

[0089] At least one enlarged diameter screw thread pile section 16 is provided, wherein the enlarged diameter screw thread pile section 16 is formed by extending part of the screw thread pile section 15 to all sides through composite compaction concrete to form an enlarged diameter screw thread pile section 16 whose outer edge outer diameter is larger than the outer edge outer diameter of the screw thread pile section 15; the enlarged diameter screw thread pile section 16 is arranged on the pile body 12 and / or the pile top 13.

[0090] A column pile section 18 is provided, which is arranged on the pile shaft 12 and / or the pile top 13 .

[0091] An enlarged diameter column pile segment 19 is provided, wherein the enlarged diameter column pile segment 19 is formed by extending the formed column pile segment to all sides through the composite compaction concrete, and the outer edge outer diameter is larger than the outer edge outer diameter of the column pile segment. The enlarged diameter column pile segment 19 is arranged on the pile body 12 and / or the pile top 13.

[0092] Depending on the geological conditions, the depth of the screw thread extending into the hole wall can be deep or shallow, thereby forming a deep screw thread pile section or a shallow screw thread pile section or a mixture of a deep screw thread pile section and a shallow screw thread pile section.

[0093] The outer diameter of the outer edge of the column pile section is D1, which is equal to the outer diameter of the drilling tool used for the foundation pile hole. The outer diameter of the deep thread pile section is D2, D2 = (1.2 ~ 1.8) D1, the outer diameter of the shallow thread pile section is D6, D2> D6> D1, the outer diameter of the expanded diameter thread pile section is D3, D3> D2, the outer diameter of the pile bottom enlarged head is D4, D3> D4> D1, and the outer diameter of the expanded diameter column pile section is D5, D3> D5> D1. The pitch of the thread pile section is T, T = (1.15 ~ 1.8) D1, and the vertical cross section of the thread is approximately trapezoidal, with an upper base width M = 50 ~ 100 mm and a lower base width N = 100 ~ 180 mm.

[0094] In one embodiment, Fig.13 The first concrete cast-in-place pile structure with an enlarged diameter screw thread pile section is a schematic diagram of the invention. The structure is as follows: the pile bottom 11 is: an enlarged head structure 14 formed by extending the concrete main pile 10 to the surroundings through the composite compaction of concrete. The pile body 12 is: from the pile bottom upward, it is a column pile section 18, a screw thread pile section 15, an enlarged diameter screw thread pile section 16 and a screw thread pile section 15. The pile top 13 is: the screw thread pile section 15.

[0095] In one embodiment, Fig.14 The second concrete cast-in-place pile structure with an enlarged diameter screw thread pile section created by the present invention is schematically shown. The structure is as follows: the pile bottom 11 is: an enlarged head structure 14 formed by extending the concrete main pile 10 to the surroundings through multiple compacted concrete. The pile body 12 is: from the pile bottom section upward, it is a column pile section 18, a screw thread pile section 15, an enlarged diameter screw thread pile section 16 and a screw thread pile section 15. The pile top 13 is: a column pile section 18.

[0096] In one embodiment, Fig.15 The third type of concrete cast-in-place pile structure with an enlarged diameter screw thread pile section created by the present invention is schematically shown. The structure is as follows: the pile bottom 11 is: an enlarged head structure 14 formed by extending the concrete main pile 10 to the surroundings through multiple compacted concrete. The pile body 12 is: from the pile bottom section upward, it is a column pile section 18, a screw thread pile section 15, an enlarged diameter screw thread pile section 16 and a screw thread pile section 15. The pile top 13 is: an enlarged diameter column pile section 19.

[0097] In one embodiment, Fig.16 The fourth type of concrete cast-in-place pile with enlarged diameter screw thread pile section is a schematic diagram of the present invention. The structure is as follows: the pile bottom 11 is: an enlarged head structure 14 formed by extending the concrete main pile 10 to the surroundings through the composite compaction of concrete. The pile body 12 is: composed of screw thread pile section 15. The pile top 13 is: an enlarged diameter screw thread pile section 16.

[0098] In one embodiment, Fig.17 The fifth concrete cast-in-place pile structure with an enlarged diameter screw thread pile section created by the present invention is schematically shown. The structure is as follows: the pile bottom 11 is: an enlarged head structure 14 formed by extending the concrete main pile 10 to the surroundings through multiple compacted concrete. The pile body 12 is: from the pile bottom section upward, there are screw thread pile section 15, column pile section 18, screw thread pile section 15. The pile top 13 is: an enlarged diameter screw thread pile section 16.

[0099] In one embodiment, Fig.18 The sixth concrete cast-in-place pile structure with an enlarged diameter screw thread pile section created by the present invention is schematically shown. The structure is as follows: the pile bottom 11 is: an enlarged head structure 14 formed by extending the concrete main pile 10 to the surroundings through multiple compacted concrete. The pile body 12 is: from the pile bottom section upward, there are screw thread pile section 15, enlarged diameter screw thread pile section 16, screw thread pile section 15. The pile top 13 is: enlarged diameter screw thread pile section 16.

[0100] (II) Construction method

[0101] Using the drill bit device of Example 1, Figure 19-23 As shown, the following steps are included:

[0102] 1) Level the site, lay out the lines according to the drawings, determine the pile positions, and mark them;

[0103] 2) The coupling 1 of the drill bit device is assembled through the drill rod and the pile driver power head, the rotary slider mechanism control system and the concrete pumping device, and the pile driver is started to drive the drill bit with the rotary slider 8-5 in a fully retracted state to rotate and squeeze the soil to form a cylindrical hole until the designed depth of the pile hole is reached;

[0104] 3) In the process of matching the drilling and pressure pouring, the formation of each pile section is realized:

[0105] 3.1) Formation of the enlarged head structure at the bottom of the pile: the rotary slide block 8-5 in the drill bit device is in a fully retracted state, the drill is lifted and concrete is poured. When the bottom end of the drill bit device is 1.5 to 2 m above the pile bottom, the lifting of the drill and the pouring are stopped, and the rotating drill bit device is released downward again to drill. The pressure concrete in the pile hole pushes the door 7-5 to rotate upward to close the discharge port channel. At the same time, the lower part of the drill bit is used to squeeze the concrete in the pile hole to perform double-dense concrete. The rock and soil wall of the pile hole is squeezed and expanded by double-dense concrete to form an expanded rock and soil aperture. Most of the concrete in the pile hole remains in the inner cavity of the rock and soil hole of the expanded part, and is squeezed and drilled to the bottom of the pile. It rotates in place for 1 minute to fully mix the loose soil and concrete at the bottom of the pile, fully compact the rock and soil hole wall at the bottom of the pile, and then the drill is lifted and the concrete is pumped. The injected concrete is integrated with the original concrete in the pile hole, and the mixed loose soil and concrete mixture is pressed on the bottom of the pile. The drill is lifted and poured to 1 m above the bottom of the pile. .5~2m high, complete the construction of the pile bottom section enlarged head structure;

[0106] 3.2) Formation of column pile section: Keep the rotary slide block 8-5 in the drill device in a fully retracted state, lift the drill and pump concrete to form the column pile section;

[0107] 3.3) Formation of screw-thread pile section: In the process of lifting the drill bit device rotating in the drilling direction and pumping concrete, the rotating slider mechanism 8 control system is used to rotate the rotating slider 8-5 to extend the core tube and the spiral blade, and squeeze into the rock and soil of the pile hole wall. At the same time, the drilling tool speed is adjusted to ensure that the screw groove formed by the rotating slider 8-5 in the rock and soil of the pile hole wall rises in a spiral line to meet the requirements of the designed pitch. The pressure concrete in the foundation pile hole is immediately filled into the screw groove and poured together with the concrete main pile hole, forming a spirally coiled screw 17 protruding outwards with an integrated structure with the outer edge of the concrete main pile, forming a screw-thread pile section 15;

[0108] 3.4) Formation of enlarged diameter screw pile section: lift the drill and pour the screw pile section to a certain designed height, stop lifting the drill and pouring, start the control system of the rotary slider mechanism 8, retract the rotary slider 8-5, and release the drill bit device rotating in the drilling direction downward again. Under the action of the pressure concrete in the screw pile hole, the door 7-5 closes the discharge port, and the lower part of the drill bit performs re-extrusion of the concrete in the screw pile section. The re-extrusion of concrete is used to squeeze the rock and soil in contact with the hole wall, and the pore diameter of the rock and soil is squeezed and expanded. Most of the squeezed concrete remains in the squeezed and expanded hole cavity. After the squeeze and expansion drilling reaches the designed depth, the drill is lifted and the concrete is pressure-poured. The poured concrete is integrated with the concrete retained in the hole. The drill is lifted and pressure-poured to the designed height to form an enlarged diameter screw pile section;

[0109] 3.5) Formation of enlarged diameter column pile section: lift the drill and pressure-grout the column pile section to the designed height, stop lifting the drill and pressure-grouting, release the drill bit device rotating in the drilling direction downward again, the pressure concrete in the foundation pile hole pushes the door 7-5 to close the discharge port, the lower part of the drill bit performs re-extrusion drilling of the concrete in the column pile section, and the re-extruded concrete squeezes the rock and soil wall of the pile hole to form an enlarged diameter rock and soil pore size, most of the squeezed concrete remains in the inner cavity of the enlarged diameter rock and soil, after squeezing and drilling to the designed depth, lift the drill and pressure-grout the concrete again, the poured concrete is integrated with the concrete retained in the hole, lift the drill and pressure-grout to the designed height, and form an enlarged diameter column pile section.

[0110] The present invention creates a principle for a drill bit to squeeze concrete in a pile hole: the outer surface of a core tube II4 at the lower part of the drill bit is provided with a conical structure, which exerts radial downward squeezing force on the concrete in the pile hole, and a spiral blade II5 with a soil squeezing notch 5-1 on the outer edge, a spiral blade II5 with a trapezoidal end cross section and a lower plane of a door 7-5 all exert radial downward squeezing force on the concrete in the pile hole.

[0111] 4) Place the prefabricated steel cage or components into the poured pile hole to meet the design elevation.

[0112] The formation principle of the external thread of the foundation pile (with a diameter of D1): in the process of lifting the drill tool rotating in the drilling direction and pumping concrete, the control system of the rotating slider mechanism is started to rotate and extend the rotating slider, and squeeze it into the rock and soil of the pile hole wall, forming a spiral upward ladder-shaped groove in the rock and soil of the pile hole side wall. Because in the drill bit with a frustum-shaped outer edge of the spiral blade II, the rotating slider is arranged at the lower end of the spiral blade I, that is, at the maximum outer edge diameter of the bottom of the drill bit; or in the drill bit with a cylindrical outer edge of the spiral blade II, the rotating slider is arranged above the cutting teeth at the lower end of the spiral blade II, that is, at the bottom end of the maximum outer edge diameter of the drill bit, both of which are in the interface of the pressure concrete in the pile hole during pouring, so that the groove formed by the rotating slider is immediately filled with the pressure concrete in the pile hole, and is carried out synchronously with the pouring of the foundation pile hole, thereby ensuring the strength between the thread and the foundation pile.

[0113] When the rotating slider forms a spiral groove, a small amount of rock and soil will be squeezed down. The residual soil formed will be transported from bottom to top along the upper surface of the spiral blade of the rotating drill bit under the action of the pressure concrete below, ensuring the quality of the pile. At the same time, after the rotating slider is rotated and extended through the hydraulic control system, the cavity of the oil cylinder has been locked. When squeezing the rock and soil of the pile hole wall to form a groove, the energy storage of the pre-tightened compression spring is used to automatically adjust the size and depth of the groove on the pile hole wall within a certain range according to the compressibility of the rock and soil, thereby forming a large and deep screw pile section in the rock and soil layer with high compressibility, and a small and shallow screw pile section in the rock and soil layer with low compressibility, avoiding the occurrence of drill jamming.

[0114] Treatment of loose soil at the bottom of the pile: first pour concrete into the bottom of the pile hole, cover the loose soil with concrete, and then use a spiral drill to squeeze the concrete in the pile hole until the bottom of the hole. Part of the concrete in the pile hole is squeezed into the loose soil at the bottom of the pile hole, and the drill tip rotates and mixes to form a mixture of concrete and loose soil. At the same time, the rock and soil at the bottom of the pile hole are further squeezed and compacted. By lifting the drill and pressing concrete again, this mixture is squeezed to the bottom of the pile and integrated with the concrete, changing the properties of the loose soil at the bottom of the pile and improving the bearing capacity of the bottom of the pile.

Claims

1. A drill bit device for concrete cast-in-place pile with an enlarged diameter screw thread pile section, comprising a joint (1), a spiral blade I (2), a core tube I (3), a core tube II (4), a spiral blade II (5), a cutting tooth (6) and a drill tip device (7), wherein the drill tip device (7) comprises a double-ear plate seat I (7-1), a double-ear plate seat II (7-2), a shaft I (7-3), a drill tip (7-4) and a door (7-5), wherein the double-ear plate seat I (7-1) and the double-ear plate seat II (7-2) are symmetrically fixed to the lower end of the core tube II (4), The inner gears are arranged in a straight line, the upper end of the drill tip (7-4) is formed into a U-shaped structure, one end of the U-shaped structure of the drill tip (7-4) is fixed to the double-ear plate seat II (7-2) through the shaft I (7-3), the other end of the U-shaped structure of the drill tip (7-4) is movably matched with the double-ear plate seat I (7-1), the door (7-5) is fixed to the middle and upper part of the drill tip (7-4), the outer edge of the door (7-5) coincides with the outer edge of the lower end surface of the core tube II (4), and the drill tip (7-4) and the door (7-5) rotate together around the shaft I (7-3); the characteristics are as follows: The outer edge of the outer surface of the core tube II (4) after being wound with the spiral blade II (5) forms a frustum shape, and the lower end surface of the core tube II (4) forms an angle β with the horizontal plane, β=0-30°; a limit contact point (D) is provided on the lower end surface of the double-ear plate seat II (7-2) for limiting the door (7-5) from being swung open to a maximum angle α, the angle α being the angle between the upper plane of the door (7-5) and the horizontal plane, α=10-40°; a rotating slider mechanism (8) is provided, the rotating slider mechanism (8) is arranged in the inner cavity of the drill bit device, and is composed of an articulated seat (8-1), a shaft II (8-2), a cylinder device (8-3), a shaft III (8-4), a rotating slider (8-5), a shaft IV (8-6) and a fixed seat (8-7), the articulated seat (8-1) is fixed to the core tube I (3 ), a fixed seat (8-7) is fixed to the lower end of the core tube I (3), a middle portion of the rotating slider (8-5) is connected to the fixed seat (8-7) through an axis IV (8-6), the rotating slider (8-5) rotates around the axis IV (8-6), the rotating slider (8-5) is arranged at the lower end of the spiral blade I (2), and on the spiral line of the spiral blade I (2), the spiral blade I (2) and the core tube I (3) are provided with a notch for the rotating slider (8-5) to rotate through, the other end of the rotating slider (8-5) is connected to the cylinder device (8-3) through the axis III (8-4), and the other end of the cylinder device (8-3) is hinged to the hinge seat (8-1) through the axis II (8-2); the working end (8-5-1) of the rotating slider (8-5) is a trapezoidal structure.

2. A drill bit device for concrete cast-in-place piles with enlarged diameter screw pile sections according to claim 1, characterized in that: The outer edge of the outer surface of the core tube II (4) after being wound with the spiral blade II (5) forms a columnar shape, and the fixing seat (8-7) is fixed to the lower end of the core tube II (4). The rotating slider (8-5) is arranged above the cutting teeth (6) at the lower end of the spiral blade II (5). The spiral blade II (5) and the core tube II (4) are provided with a notch for the rotating slider (8-5) to rotate through, and the rotating slider (8-5) and the spiral blade II (5) are on the same spiral line.

3. A drill bit device for forming a concrete cast-in-place pile with an enlarged diameter screw pile section according to claim 1 or 2, characterized in that: The oil cylinder device (8-3) comprises an oil cylinder (8-3-1), an outer sleeve (8-3-2), a slide rod (8-3-3), a hinge (8-3-4), a nut (8-3-5), a spring seat (8-3-6), a push rod (8-3-7) and a preloaded compression spring (8-3-8); one end of the push rod (8-3-7) is connected to the piston rod of the oil cylinder (8-3-1), and the other end is fixed to the nut (8-3-5), and the preloaded compression spring (8-3-8) and the spring seat (8-3-6) are passed through the slide rod (8-3-7). One end of the outer sleeve (8-3-2) is connected to the outer diameter of the oil cylinder (8-3-1), and the inner diameter of the other end is sealed and slidably matched with the outer diameter of one end of the slide rod (8-3-3). The rotating slide block (8-5) is connected to the hinge (8-3-4) of the oil cylinder device (8-3) through the shaft III (8-4), and the oil cylinder device (8-3) is connected to the hinge seat (8-1) through the oil cylinder (8-3-1) and the shaft II (8-2).

4. A drill bit device for forming a concrete cast-in-place pile with an enlarged diameter screw pile section according to claim 3, characterized in that: The preload force of the preload compression spring (8-3-8) is equal to the maximum thrust value of the cylinder (8-3-1).

5. A drill bit device for forming a concrete cast-in-place pile with an enlarged diameter screw pile section according to claim 1, characterized in that: β=5-25°；α=15-30°。 6. A drill bit device for concrete cast-in-place piles with enlarged diameter screw pile sections according to claim 1, characterized in that: The coupling (1), the core tube I (3) and the core tube II (4) are coaxially fixed in sequence to form an integral structure, and a passage for concrete to pass through is provided inside. The outer surfaces of the coupling (1) and the core tube I (3) are wound with spiral blades I (2), and the outer surface of the core tube II (4) is wound with spiral blades II (5). The upper end surface of the spiral blade II (5) is correspondingly connected to the lower end surface of the spiral blade I (2), and the lower end of the spiral blade II (5) is provided with cutting teeth (6).

7. A drill bit device for concrete cast-in-place piles with enlarged diameter screw pile sections according to claim 6, characterized in that: Two spiral blades II (5) are provided. The two spiral blades II (5) are symmetrically mounted on the outer surface of the core tube II (4), and the upper end surface of one spiral blade II (5) is correspondingly connected to the lower end surface of the spiral blade I (2).

8. A drill bit device for forming a concrete cast-in-place pile with an enlarged diameter screw pile section according to claim 1, characterized in that: The outer shape of the core tube II (4) is a frustum-shaped body, or a frustum-shaped body at the upper end and a columnar body at the lower end.

9. A drill bit device for concrete cast-in-place piles with enlarged diameter screw pile sections according to claim 1, characterized in that: When the door (7-5) is rotated to the maximum position, an angle δ is formed between the lower end surface of the core tube II (4) and the upper plane of the door (7-5), δ=35-50°.

10. A method for forming a concrete cast-in-place pile with an enlarged diameter screw thread pile section, characterized in that: Using the drill bit device according to any one of claims 1 to 9, comprising the following steps: 1) Level the site, lay out the lines according to the drawings, determine the pile positions, and mark them; 2) Use the joint of the drill bit device to assemble the pile driver power head, the rotary slider mechanism control system and the concrete pumping device through the drill rod, aim at the pile position, start the pile driver, and drive the drill bit with the rotary slider in a fully retracted state to rotate and squeeze the soil to form a cylindrical hole until the designed depth of the pile hole is reached; 3) In the process of matching the drilling and pressure pouring, the formation of each pile section is realized: 3.1) Formation of the enlarged head structure at the bottom of the pile: The rotating slider in the drill bit device is in a fully retracted state, the drill is lifted and concrete is poured. When the bottom end of the drill bit device is 1.5 to 2 meters above the pile bottom, the lifting of the drill and the pouring are stopped, and the rotating drill bit device is released downward again for drilling. The pressure concrete in the pile hole pushes the door to rotate upward to close the discharge port channel. At the same time, the lower part of the drill bit is used to squeeze the concrete in the pile hole for re-dense concrete. The re-extruded concrete squeezes and expands the rock and soil wall of the pile hole to form an enlarged rock and soil aperture. Most of the concrete in the pile hole remains in the inner cavity of the rock and soil hole of the expanded part, squeezes and drills to the bottom of the pile, rotates in place for 1 minute, fully mixes the loose soil and concrete at the bottom of the pile, and fully compacts the rock and soil hole wall at the bottom of the pile. Then, the drill tool is lifted and the concrete is pumped and poured. The injected concrete is integrated with the original concrete in the pile hole, and the mixed loose soil and concrete mixture is pressed on the pile bottom. The drill is lifted and poured to a height of 1.5 to 2 meters from the pile bottom to complete the construction of the enlarged head structure at the bottom of the pile. 3.2) Formation of column pile section: Keep the rotary slide in the drill device in a fully retracted state, lift the drill bit and pump concrete to form the column pile section; 3.3) Formation of screw-thread pile section: During the process of lifting the drill bit device rotating in the drilling direction and pumping concrete, the rotating slider mechanism control system is used to rotate the rotating slider to extend the core tube and spiral blades and squeeze into the rock and soil of the pile hole wall. At the same time, the drilling tool speed is adjusted to ensure that the screw groove formed by the rotating slider in the rock and soil of the pile hole wall rises in a spiral line to meet the requirements of the designed pitch. The pressure concrete in the foundation pile hole is immediately filled into the screw groove and poured together with the concrete main pile hole, forming a spirally coiled screw tooth that protrudes outward and is an integrated structure with the outer edge of the concrete main pile, forming a screw-thread pile section; 3.4) Formation of the enlarged diameter screw thread pile section: lift the drill and pour the screw thread pile section to a certain designed height, stop lifting the drill and pouring, start the rotary slider mechanism control system, retract the rotary slider, and release the drill bit device rotating in the drilling direction downward again. Under the action of the pressure concrete in the screw thread pile hole, the door closes the discharge port, and the lower part of the drill bit performs re-extrusion of the concrete in the screw thread pile section. The re-extruded concrete is used to squeeze the rock and soil in contact with the hole wall, and the rock and soil pore diameter is expanded. Most of the squeezed concrete remains in the squeezed and expanded hole cavity. After the extrusion and expansion drilling reaches the designed depth, the drill is lifted and the concrete is pressure-poured. The poured concrete is integrated with the concrete retained in the hole. The drill is lifted and pressure-poured to the designed height to form the enlarged diameter screw thread pile section; 3.5) Formation of the expanded diameter column pile section: lift the drill and pressure-grout the column pile section to the designed height, stop lifting the drill and pressure-grouting, release the drill bit device rotating in the drilling direction downward again, the pressurized concrete in the foundation pile hole pushes the door to close the discharge port, the lower part of the drill bit performs re-extrusion drilling of the concrete in the column pile section, and the re-extruded concrete squeezes the rock and soil wall of the pile hole to form an expanded diameter rock and soil pore. Most of the squeezed concrete remains in the inner cavity of the expanded diameter rock and soil. After extrusion drilling to the designed depth, lift the drill and pressure-grout the concrete again. The poured concrete is integrated with the concrete retained in the hole, lift the drill and pressure-grout to the designed height to form an expanded diameter column pile section.

11. A cast-in-place concrete pile with an enlarged diameter screw thread pile section produced by the cast-in-place concrete pile with an enlarged diameter screw thread pile section method as claimed in claim 10, comprising a concrete main pile (10), wherein the concrete main pile (10) consists of a pile bottom (11), a pile body (12) and a pile top (13); characterized in that: The pile bottom (11) is in the shape of an enlarged head structure (14) formed by extending the concrete main pile (10) to the surroundings through the composite compacting concrete; a screw thread pile section (15) and at least one section of enlarged diameter screw thread pile section (16) are provided, wherein the screw thread pile section (15) is a screw thread (17) protruding outwards and wound in an integral structure formed on the outer edge of the concrete main pile (10); and the enlarged diameter screw thread pile section (16) is formed by extending part of the screw thread pile section (15) to the surroundings through the composite compacting concrete. The enlarged diameter screw pile section (16) has an outer diameter greater than the outer diameter of the outer edge of the screw pile section (15); the cross section of the screw (17) is a trapezoidal structure; the screw pile section (15) is arranged on the pile body (12) and / or the pile top (13); the enlarged diameter screw pile section (16) is arranged on the pile body (12) and / or the pile top (13); the composite extrusion concrete is used to extrude and expand the rock and soil wall of the pile hole by composite extrusion concrete to form an enlarged rock and soil hole diameter, and most of the concrete in the pile hole is retained in the inner cavity of the rock and soil hole of the enlarged part.

12. The concrete cast-in-place pile with enlarged diameter screw thread pile section according to claim 11, characterized in that: A column pile section (18) is provided, and the column pile section (18) is arranged on the pile body (12) and / or the pile top (13).

13. The concrete cast-in-place pile with an enlarged diameter screw thread pile section according to claim 11, characterized in that: An enlarged diameter column pile segment (19) is provided. The enlarged diameter column pile segment (19) is formed by extending the formed column pile segment to all sides through composite compaction of concrete to form an enlarged diameter column pile segment (19) with an outer edge outer diameter greater than the outer edge outer diameter of the column pile segment. The enlarged diameter column pile segment (19) is arranged on the pile body (12) and / or the pile top (13).

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