An easy-to-install precast pile implantation mechanism and installation method

Abstract

This invention relates to the field of pile foundation construction technology, and discloses an easy-to-install precast pile mechanism and installation method with an enlarged-hole insertion method. The mechanism includes a pile body vertically installed in a pilot hole. An internal grouting cavity is formed at the top of the pile body along its length. A diameter-changing zone is provided in the middle of the pile body, and a conical guide shoe is provided at the bottom. Expansion grooves are formed on all four sides of the bottom outer wall of the pile body. A support and locking mechanism is arranged within the expansion grooves, and lateral support wings are inserted into the expansion grooves. The support and locking mechanism locks the relative position between the lateral support wings and the pile body. The outer walls of the four lateral support wings abut against the borehole wall, ensuring the pile body remains vertical throughout its insertion, even in complex geological conditions of frozen soil mixed with ice layers. The pile head remains intact without breakage, and the stress distribution in the pile body is balanced, completely solving construction problems such as pile breakage and deflection in cold regions.

Description

Technical Field

[0001] This invention relates to the field of pile foundation construction, and more specifically, to a precast pile mechanism for easy installation via enlarged borehole and its installation method. Background Technology

[0002] Cold regions are widely distributed in my country, and foundation engineering construction in these areas primarily utilizes bored piles and traditional precast piles. The pre-drilled precast pile construction process is an innovative method that offers several advantages over traditional precast pile and bored pile construction techniques. In some complex geological conditions in cold regions, pre-drilling followed by hammer driving effectively reduces pile damage, allows for better penetration of medium-coarse sand layers, increases the bearing capacity of individual piles, accelerates construction progress, and ensures project quality.

[0003] During construction in cold regions, the pile body is affected by ice layers in the frozen soil during hammering, causing the pile body to deflect. When the pile head is impacted, the pile head may break. At the same time, there is a sudden change in stiffness at the interface between the traditional steel pile cap and the concrete pile head. When ice layers are mixed in the frozen soil, the hammering stress will form shear force at this interface, causing the pile to break. Summary of the Invention

[0004] This invention provides an easy-to-install precast pile mechanism and installation method with an expanded borehole, solving the technical problem in related technologies where piles break during implantation due to ice layers in cold regions.

[0005] This invention provides an easy-to-install precast pile mechanism with an enlarged pilot hole, including a pile body vertically disposed in the pilot hole, an internal grouting cavity opened from the top of the pile body along the length of the pile body, a diameter-changing area provided in the middle of the pile body, and a conical pilot shoe provided at the bottom of the pile body.

[0006] Expansion grooves are opened on all four sides of the bottom outer wall of the pile body. A support locking mechanism is arranged in the expansion groove. A lateral support wing is inserted in the expansion groove. A connecting column is connected to the inner wall of the lateral support wing. A push plate is provided on the side of the connecting column near the inner grouting cavity. The outer edge of the push plate is slidably connected in the expansion groove.

[0007] The support locking mechanism includes a push ring, a support spring, and a pin. A column groove is opened in the wall of the telescopic groove. The support spring is sleeved on the end of the pin. Both the support spring and the pin are inserted into the column groove. A guide groove is provided around the push ring. The guide groove is a right trapezoidal structure. In the initial state, the end of the pin away from the support spring is connected to the bottom of the guide groove. A column hole is opened on the outer side of the push plate. The diameter of the column hole is the same as the outer diameter of the pin. When the push plate drives the push ring to move, the pin slides continuously along the groove of the guide groove until the pin is inserted into the column hole, locking the relative position between the lateral support wings and the pile body. The outer walls of the four lateral support wings abut against the hole walls of the guide holes, so that the pile body always remains vertical.

[0008] Prestressed steel strands are installed on the inner wall of the pile. The prestressed steel strands are distributed in a double helix structure within the pile body, and self-regulating heating wires are embedded in the prestressed steel strands.

[0009] Furthermore, the variable diameter zone includes a stress buffer cavity and variable diameter reinforcing ribs. The variable diameter reinforcing ribs are located on the inner walls of both ends of the stress buffer cavity. The variable diameter reinforcing ribs are annular structures, and several sets of variable diameter reinforcing ribs are arranged in parallel on the variable diameter zone.

[0010] Furthermore, the lateral support wing is an arc-shaped plate structure with a pointed bottom and a cutting edge at the tip. The connection angle between the lateral support wing and the connecting column is between 5° and 10°, and the tip of the lateral support wing faces the conical guide shoe.

[0011] Furthermore, an inner support cylinder is provided at the corresponding position of the inner grouting cavity in the stress buffer cavity to compensate for the cross-sectional loss of the pile body in the variable diameter zone.

[0012] Furthermore, an insulating layer is covered on the pre-embedded self-temperature-controlled heating wire, and the end of the prestressed steel strand extends out of the cavity of the inner grouting chamber.

[0013] Furthermore, it also includes a detachable pile cap, with an anti-shear key located in the middle of the inner wall of the bottom end of the pile cap. The anti-shear key is a four-way support member and is inserted into the port of the inner grouting cavity of the pile body.

[0014] Furthermore, a pile head ring is provided at the top of the pile body, and a buffer layer is provided at the connection between the pile head ring and the pile body.

[0015] Furthermore, the pile cap includes a top layer and a middle layer. The middle layer is embedded inside the top layer. The top layer is used to absorb instantaneous impacts, while the middle layer is a honeycomb steel plate used to uniformly distribute stress.

[0016] Furthermore, a carbide cutting edge is distributed in a ring on the tapered guide shoe, and the carbide cutting edge is serrated.

[0017] This invention also proposes an installation method for an easily installed precast pile mechanism with enlarged boreholes, comprising the following steps:

[0018] S100, Pre-hole positioning: Use a rotary drilling rig to create a pre-hole, continuously clear the soil in the pit from the pre-hole, and after shaping, lay a layer of crushed stone at the bottom of the hole;

[0019] S200, hoisting and driving piles: the hoisting point is set on the pile body, a double hook balancing system is adopted, the conical guide shoe is aligned with the hole position and sinks at a uniform speed, the cutting edge of the conical guide shoe is used to cut the soil layer, and the verticality is monitored in real time.

[0020] S300, lateral support wing deployment: Cement grout is injected under high pressure through the internal grouting cavity. The level of the cement grout is below the diameter change zone. The grout pushes the push plate to move outward, which drives the connecting column to push the lateral support wing out and fit it against the hole wall of the pilot hole.

[0021] The push plate first engages with the end face of the push ring, then the continuous displacement of the push plate squeezes the push ring, and the inclined surface of the guide groove forces the pin to compress the support spring. When the push plate moves to the point where the pin hole is aligned with the pin, the support spring releases and pushes the pin into the pin hole, forming a mechanical self-locking mechanism.

[0022] S400, Pile Cap Installation: After removing the laitance from the top of the pile, apply epoxy interface agent, align the anti-shear key with the port of the inner grouting cavity and press it in.

[0023] S500, staged hammer driving pile: the hammering energy is buffered by the elastic body at the top of the pile cap, and then evenly distributed to the honeycomb steel plate, and then transmitted through the pressure of the shear bond;

[0024] S600, pile end grouting reinforcement: Cement grout is injected through the reserved channel between the borehole wall and the outer wall of the pile body to form a bearing layer in the diameter change zone; the grout seeps out through the root of the lateral support wing and solidifies to form an anti-pull-out rib; micro-expansion grout is continuously injected through the inner grouting cavity to fill the inner support cylinder.

[0025] S700, Intelligent Temperature Control System Activation: Immediately after pile driving is completed, the self-regulating heating wire is activated, automatically starting at -5℃ to maintain the temperature of the soil around the pile and continuously monitoring until the grout finally sets.

[0026] The beneficial effects of this invention are as follows:

[0027] In this invention, the conical guide shoe, together with the four-way expanding lateral support wings, forms a mechanical self-locking anchor, constructing a stable guiding frame in frozen soil. This ensures that the pile body penetrates the ice layer vertically during hammer driving. The detachable pile cap absorbs the rigid impact of frozen soil through the elastic top layer, and the honeycomb steel plate middle layer uniformly disperses stress, eliminating the abrupt stiffness change at the interface between the traditional steel pile cap and concrete, thus avoiding shear fracture. The double-helix electric heating system intelligently maintains a positive temperature at the pile-soil interface, blocking the path of frost heave force formation and ensuring the continuous effectiveness of side friction resistance. The stress buffer cavity in the variable diameter zone absorbs reflected stress waves, and together with the gradual pressure conversion mechanism of the anti-shear key, the repeated hammer load in the frozen soil is smoothly transmitted to the bearing layer.

[0028] In summary, under the complex geological conditions of permafrost mixed with ice layers, the pile body maintains vertical penetration throughout the entire process, the pile head remains intact without cracks, and the stress distribution of the pile body is balanced, thus completely solving the stubborn construction problems such as broken piles and deflection in cold regions. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of an easy-to-install precast pile mechanism with enlarged borehole implantation according to the present invention;

[0030] Figure 2 This is the invention Figure 1 The main view;

[0031] Figure 3 This is the invention Figure 2 A schematic diagram of the AA cross-sectional structure;

[0032] Figure 4 This is the invention Figure 3 A magnified view of part B in the middle;

[0033] Figure 5 This is a schematic diagram of the installation process of an easy-to-install precast pile mechanism with enlarged borehole (a, b, c, and d in the figure correspond to S100, S300, S500, and S600 in the installation method, respectively).

[0034] Figure 6 This is a schematic diagram of the structure of a precast pile mechanism for easy installation of a precast pile with an enlarged borehole, wherein the lateral support wing is supported on the borehole wall.

[0035] In the diagram: 100, pile body; 110, stress buffer cavity; 120, variable diameter reinforcing bar; 130, conical guide shoe; 140, pile head ring; 150, inner support cylinder; 160, inner grouting cavity; 170, prestressed steel strand; 200, lateral support wing; 210, connecting column; 220, push plate; 300, pile cap; 310, shear key; 400, support locking mechanism; 410, push ring; 420, support spring; 430, pin; 440, column hole; 500, guide hole; 600, bearing layer. Detailed Implementation

[0036] The subject matter described herein will now be discussed with reference to exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and implement the subject matter described herein, and changes may be made to the function and arrangement of the elements discussed without departing from the scope of this specification. Various processes or components may be omitted, substituted, or added as needed in the examples. Furthermore, features described in some examples may be combined in other examples.

[0037] like Figures 1-6 As shown, an easy-to-install precast pile mechanism with enlarged borehole includes a pile body 100, which has a cylindrical structure. An inner grouting cavity 160 is formed along the length of the pile body 100 from its top. A diameter-changing zone is provided in the middle of the pile body 100, including a stress buffer cavity 110 and diameter-changing reinforcing ribs 120. The diameter-changing reinforcing ribs 120 are located on the inner walls of both ends of the stress buffer cavity 110. The diameter-changing reinforcing ribs 120 have a ring structure, and several sets of diameter-changing reinforcing ribs 120 are arranged in parallel on the diameter-changing zone. The multiple sets of diameter-changing reinforcing ribs 120 are arranged in a trapezoidal pattern. A conical guide shoe 130 is provided at the bottom of the pile body 100. A carbide cutting edge is distributed in a ring on the conical guide shoe 130. The carbide cutting edge is serrated (tooth depth 5mm, tooth spacing 20mm), and the surface of the cutting edge is nitrided (hardness ≥1200HV), increasing the rock-breaking ability by 3 times.

[0038] It should be further explained that the stress buffer cavity 110 absorbs the reflected energy of the hammer impact stress wave, and the trapezoidal arrangement of the variable diameter reinforcing ribs 120 is used to improve the circumferential strength of the variable diameter area in the pile body 100. The variable diameter area is used to reduce the risk of pile body cracking during hammering, and to provide space for grouting of the enlarged head to form the bearing layer 600.

[0039] Expansion grooves are opened on all four sides of the bottom outer wall of the pile body 100. A support locking mechanism 400 is arranged in the expansion groove. A lateral support wing 200 is inserted in the expansion groove. A connecting column 210 is connected to the inner wall of the lateral support wing 200. A push plate 220 is provided on the side of the connecting column 210 near the inner grouting cavity 160. The outer edge of the push plate 220 is slidably connected in the expansion groove.

[0040] A post hole 440 is opened on the outer periphery of the push plate 220, and the diameter of the post hole 440 is the same as the outer diameter of the pin 430.

[0041] The support locking mechanism 400 includes a push ring 410, a support spring 420, and a pin 430. A column groove is formed within the wall of the telescopic groove. The support spring 420 is sleeved on the end of the pin 430. Both the support spring 420 and the pin 430 are inserted into the column groove. A guide groove is provided around the periphery of the push ring 410. Figure 4As shown, the guide groove has a right-angled trapezoidal structure. In the initial state, the end of the pin 430 away from the support spring 420 is abutted against and connected to the bottom of the guide groove.

[0042] When the push plate 220 is pushed, the pin 430 slides along the groove of the guide groove, and finally the pin 430 is inserted into the pin hole 440.

[0043] The guide groove has two stages. In the initial state, the bottom end of the pin 430 abuts against the bottommost end. As the push ring 410 moves, the pin 430 continuously compresses the support spring 420 and inserts into the column groove. When the pin 430 abuts against the end of the guide groove, the pin is completely compressed into the column groove. When the push ring 410 continues to move, the support spring 420 resets and pushes the pin 430 out and inserts it into the column hole 440, locking the push plate 220 structure connected to the pile body 100 and the lateral support wing 200. At this time, the outer wall of the lateral support wing 200 is in close contact with the hole wall of the pilot hole 500. The outer wall of the lateral support wing 200 is smooth, which makes it easy for the lateral support wing 200 to slide down along the hole wall of the pilot hole 500 when the pile body 100 is hammered later, so that the verticality is maintained when the pile is driven by sliding along the hole wall.

[0044] It should be added that when the high-pressure grouting pushes the push plate 220, the push plate 220 squeezes the push ring 410. At this time, the pin 430 slides along the inclined surface on the guide groove to compress the spring. Finally, after aligning with the pin hole 440, it springs into lock. After locking, there is no risk of hydraulic failure. The polytetrafluoroethylene coating on the surface of the pin 430 ensures smooth operation at low temperature.

[0045] The lateral support wing 200 is an arc-shaped plate structure with a pointed bottom and a cutting edge. The connection angle between the lateral support wing 200 and the connecting column 210 is between 5° and 10°. The pointed end of the lateral support wing 200 faces the conical guide shoe 130, which facilitates the insertion of the lateral support wing 200 into the soil in the pit to form a four-way anchoring structure. That is, after unfolding, it forms an angle of 80°-85° with the axis of the pile 100, forming the best anti-pull-out key.

[0046] An inner support cylinder 150 is provided in the inner grouting cavity 160 at the corresponding position of the stress buffer cavity 110 to compensate for the cross-sectional loss of the pile body 100 in the variable diameter zone.

[0047] Prestressed steel strands 170 are provided on the inner wall of the pile body 100. The prestressed steel strands 170 are distributed in a double helix structure within the pile body 100. Self-regulating heating wires are pre-embedded in the prestressed steel strands 170 and covered with an insulation layer. The ends of the prestressed steel strands 170 extend into the cavity of the inner grouting cavity 160 for external power supply. A pre-embedded waterproof socket (IP68 rating) is used to connect to an external 36V safety voltage. The double helix structure ensures that the axial temperature difference is ≤2℃ / m and the circumferential temperature difference is ≤1℃.

[0048] When the self-regulating heating wire is below -5℃, it automatically starts heating to prevent the soil around the pile from freezing, maintains the pile-soil interface temperature >0℃, and avoids the frost heave force from weakening the side friction resistance.

[0049] It also includes a detachable pile cap 300, with an anti-shear key 310 in the middle of the inner wall of the bottom end of the pile cap 300. The anti-shear key 310 is a four-way support member. The anti-shear key 310 is inserted into the port of the inner grouting cavity 160 of the pile body 100. The top end of the pile body 100 is provided with a pile head ring 140, and a buffer layer is provided at the connection between the pile head ring 140 and the pile body 100.

[0050] The pile cap 300 includes a top layer and a middle layer. The middle layer is embedded in the top layer. The top layer is used to absorb instantaneous impact and is made of elastic material. The middle layer is a honeycomb steel plate used to evenly distribute stress and reduce the risk of concrete cracking at the pile head.

[0051] In particular, the top layer of the pile cap can buffer the rigid impact of the frozen soil layer, avoiding low-temperature brittle damage. At the same time, the pile cap 300 can be quickly replaced after damage, reducing maintenance costs.

[0052] In the area of ​​concentrated hammering stress, a pile cap 300 is set to solve the problem of stress wave reflection superposition and insufficient tensile strength of concrete during the hammering of traditional flat-head piles. The internal shear-resistant key 310 converts the destructive shear force into controllable pressure, realizing reliable shear force transfer between the pile and the pile cap 300, especially ensuring structural safety under repeated frost heave loads in cold regions.

[0053] In one embodiment of the present invention, an installation method for an easily installable precast pile mechanism with enlarged borehole is also provided, comprising the following steps:

[0054] S100, positioning of pilot hole 500: Use a rotary drilling rig to form pilot hole 500. The diameter of pilot hole 500 must be 100mm larger than the pile diameter (including the maximum outer diameter of the tapered guide shoe 130). The soil in the pit of pilot hole 500 is continuously cleaned. After forming, a 200mm thick layer of graded crushed stone is laid at the bottom of the hole to prevent damage to the hard alloy cutting edge during pile driving.

[0055] S200, hoisting and driving piles: The hoisting point is set at the upper 1 / 4 of the pile body 100. A double hook balancing system is used. After the conical guide shoe 130 is aligned with the hole, it is slid down at a uniform speed. The cutting edge is used to cut the soil layer, and the verticality is monitored in real time (deviation ≤ 0.5% of pile length).

[0056] S300, lateral support wing 200 unfolds: Cement grout (pressure ≥ 8MPa) is injected under high pressure through the inner grouting cavity 160. The level of the cement grout is below the diameter change zone. The grout pushes the push plate 220 to move outward, which drives the connecting column 210 to push the lateral support wing 200 out and fit it against the hole wall of the pilot hole.

[0057] When the push plate 220 is pushed, it first engages with the end face of the push ring 410. Then, the continuous displacement of the push plate 220 squeezes the push ring 410. The inclined surface of the guide groove forces the pin 430 to compress the support spring 420. When the push plate 220 moves to the point where the pin 430 is aligned with the post hole 440, the support spring 420 releases and pushes the pin 430 into the post hole 440, forming a mechanical self-locking mechanism (pull-out resistance ≥200kN).

[0058] At this time, the pile 100 is balanced and supported by the lateral support wings 200 on all four sides, and is always in an upright structure. The pile 100 is perpendicular to the horizontal plane and located vertically upward.

[0059] S400, Pile Cap 300 Installation: After removing the laitance from the pile top, apply epoxy interface agent. Align the shear key 310 with the 160 port of the inner grouting cavity and press it in (fitting tolerance ≤ 0.3mm). When hammering the top layer of the pile cap, control the hammer drop height ≤ 1m (to avoid plastic deformation of the honeycomb steel plate).

[0060] S500, staged hammer driving pile: the hammering energy is buffered by the elastic body at the top of the pile cap, and then evenly distributed to the honeycomb steel plate, and then pressure transmitted through the shear-resistant key 310.

[0061] S600, pile end grouting reinforcement:

[0062] High-pressure grouting: Cement grout (pressure 15MPa) is injected through the reserved channel between the borehole wall of pilot hole 500 and the outer wall of pile body 100 to form an enlarged head with a diameter ≥1.2m at the diameter change zone. The enlarged head is the bearing layer 600 (grout penetration radius 0.8m).

[0063] Side wing grouting: Grout covers the lateral support wing 200 and solidifies to form anti-pull-out ribs. The grouting pressure is reduced to 8MPa, and internal compensation grouting is also carried out simultaneously (to prevent the locking mechanism from being opened).

[0064] Internal cavity compensation grouting: Micro-expansion grout is continuously injected through the internal grouting cavity 160 to fill the internal support cylinder 150 (expansion rate 0.03%).

[0065] S700, intelligent temperature control system starts: The self-regulating heating wire is turned on immediately after the pile is driven. It starts automatically at -5℃ to maintain the soil around the pile at ≥2℃ (to prevent frost heave from weakening the frictional resistance). The double helix structure of the 170 prestressed steel strands ensures uniform heat diffusion (temperature difference ≤3℃). It is continuously monitored until the grout is finally set (generally 72 hours).

[0066] The embodiments of the present invention have been described above, but the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention, all of which are within the protection scope of the present invention.

Claims

1. A precast pile mechanism for easy installation via enlarged borehole implantation, characterized in that, It includes a pile body that is vertically installed in the pilot hole, an internal grouting cavity that is opened from the top of the pile body along the length of the pile body, a diameter change zone in the middle of the pile body, and a conical pilot shoe at the bottom of the pile body. Expansion grooves are opened on all four sides of the bottom outer wall of the pile body. A support locking mechanism is arranged in the expansion groove. A lateral support wing is inserted in the expansion groove. A connecting column is connected to the inner wall of the lateral support wing. A push plate is provided on the side of the connecting column near the inner grouting cavity. The outer edge of the push plate is slidably connected in the expansion groove. The support locking mechanism includes a push ring, a support spring, and a pin. The wall of the telescopic groove has a column groove. The support spring is sleeved on the end of the pin. Both the support spring and the pin are inserted into the column groove. The push ring has a guide groove around its periphery. The guide groove has a right-angled trapezoidal structure. In the initial state, the end of the pin away from the support spring is connected to the bottom of the guide groove. A column hole is opened on the periphery of the push plate. When the push plate moves the push ring, the pin slides continuously along the groove of the guide groove until the pin is inserted into the column hole, locking the relative position between the lateral support wings and the pile body. The outer walls of the four lateral support wings abut against the hole walls of the guide holes, so that the pile body always remains vertical. Prestressed steel strands are installed on the inner wall of the pile. The prestressed steel strands are distributed in a double helix structure within the pile body, and self-regulating heating wires are embedded in the prestressed steel strands.

2. The easily installable precast pile mechanism with enlarged borehole as described in claim 1, characterized in that, The variable diameter zone includes a stress buffer cavity and variable diameter reinforcing ribs. The variable diameter reinforcing ribs are located on the inner walls of both ends of the stress buffer cavity. The variable diameter reinforcing ribs are annular structures, and several sets of variable diameter reinforcing ribs are arranged in parallel on the variable diameter zone.

3. The easily installable precast pile mechanism with enlarged borehole as described in claim 2, characterized in that, The lateral support wing is an arc-shaped plate structure with a pointed bottom and a cutting edge. The connection angle between the lateral support wing and the connecting column is between 5° and 10°, and the pointed end of the lateral support wing faces the conical guide shoe.

4. The easily installable precast pile mechanism with enlarged borehole as described in claim 3, characterized in that, An inner support cylinder is provided at the corresponding position of the stress buffer cavity in the inner grouting cavity to compensate for the cross-sectional loss of the pile body in the variable diameter zone.

5. The easily installable precast pile mechanism with enlarged borehole as described in claim 4, characterized in that, An insulating layer is covered on the pre-embedded self-temperature-controlled heating wire, and the end of the prestressed steel strand extends out of the cavity of the inner grouting chamber.

6. The easily installable precast pile mechanism with enlarged borehole as described in claim 5, characterized in that, It also includes a detachable pile cap, with a shear-resistant key in the middle of the inner wall at the bottom of the pile cap. The shear-resistant key is a four-way support and is inserted into the port of the inner grouting cavity of the pile body.

7. The easily installable precast pile mechanism with enlarged borehole as described in claim 6, characterized in that, The top of the pile is equipped with a pile head ring, and a buffer layer is provided at the connection between the pile head ring and the pile body.

8. The easily installable precast pile mechanism with enlarged borehole as described in claim 7, characterized in that, The pile cap consists of a top layer and a middle layer. The middle layer is embedded inside the top layer. The top layer is used to absorb instantaneous impacts, while the middle layer is made of honeycomb steel plate and is used to evenly distribute stress.

9. A precast pile mechanism for easy installation via enlarged borehole implantation according to claim 8, characterized in that, Carbide cutting edges are distributed in a ring on the tapered guide shoe, and the carbide cutting edges are serrated.

10. An installation method for an easily installable precast pile mechanism with enlarged borehole implantation, used for installing the easily installable precast pile mechanism with enlarged borehole implantation as described in claim 9, characterized in that, Includes the following steps: S100, Pre-hole positioning: Use a rotary drilling rig to create a pre-hole, continuously clear the soil in the pit from the pre-hole, and after shaping, lay a layer of crushed stone at the bottom of the hole; S200, hoisting and driving piles: the hoisting point is set on the pile body, a double hook balancing system is adopted, the conical guide shoe is aligned with the hole position and sinks at a uniform speed, the conical guide shoe is used to cut the soil layer, and the verticality is monitored in real time. S300, lateral support wing deployment: Cement grout is injected under high pressure through the internal grouting cavity. The level of the cement grout is below the diameter change zone. The grout pushes the push plate to move outward, which drives the connecting column to push the lateral support wing out and fit it against the hole wall of the pilot hole. The push plate first engages with the end face of the push ring, then the continuous displacement of the push plate squeezes the push ring, and the inclined surface of the guide groove forces the pin to compress the support spring. When the push plate moves to the point where the pin hole is aligned with the pin, the support spring releases and pushes the pin into the pin hole, forming a mechanical self-locking mechanism. S400, Pile Cap Installation: After removing the laitance from the top of the pile, apply epoxy interface agent, align the anti-shear key with the port of the inner grouting cavity and press it in. S500, staged hammer driving pile: the hammering energy is buffered by the elastic body at the top of the pile cap, and then evenly distributed to the honeycomb steel plate, and then transmitted through the pressure of the shear bond; S600, pile end grouting reinforcement: Cement grout is injected through the reserved channel between the borehole wall and the outer wall of the pile body to form a bearing layer in the diameter change zone; the grout seeps out through the root of the lateral support wing and solidifies to form an anti-pull-out rib; micro-expansion grout is continuously injected through the inner grouting cavity to fill the inner support cylinder. S700, Intelligent Temperature Control System Activation: Immediately after pile driving is completed, the self-regulating heating wire is activated, automatically starting at -5℃ to maintain the temperature of the soil around the pile and continuously monitoring until the grout finally sets.

Images