A pile driving aid device and construction method for precast pipe piles

Abstract

This invention discloses a pile driving aid device and construction method for precast pipe piles. The device includes a driving aid assembly, which comprises a connecting assembly, a drill rod assembly, a drive box assembly, a reamer assembly, and a main drill bit. One end of the connecting assembly is connected to one end of the drill rod assembly, and the other end is used to connect to external equipment. The reamer assembly is connected to the drive box assembly. The drive box assembly, sleeved on the drill rod assembly, drives the reamer assembly to slide along the axial direction of the drill rod assembly, so that the reamer assembly is housed inside or exposed outside the precast pipe pile's borehole. The drill rod assembly is connected to the main drill bit, which is used to drill into the stratum covered by the projection surface of the precast pipe pile's inner cavity. The reamer assembly is used to drill into the stratum outside the projection surface of the precast pipe pile's inner cavity, thereby enabling the drilling of a borehole with a diameter larger than that of the precast pipe pile through the main drill bit and the reamer bit. The pilot hole diameter of this invention is larger than the pile's outer diameter, greatly reducing or even eliminating the pile driving resistance in hard soil layers.

Description

Technical Field

[0001] This invention relates to the field of pipe pile construction technology, specifically a pile driving aid device and construction method for precast pipe piles. Background Technology

[0002] Precast pipe piles (such as steel pipe piles and PHC pipe piles) are widely used in construction projects for buildings, municipal roads, bridges, and ports, offering advantages such as high pile-driving efficiency and easy quality control. Precast pipe piles are generally driven using methods such as impact, vibration, and static pressure, with impact driving exhibiting the strongest adaptability to different geological formations. Impact driving can penetrate relatively hard soil and rock layers, such as dense sand layers and strongly weathered rock layers. However, impact driving is limited by the allowable stress of the precast pipe pile material and the capabilities of the pile driving equipment. When penetrating deeper into hard strata, or encountering even harder moderately weathered rock layers or large boulder formations, precast pipe piles may struggle to reach the designed depth, and forced penetration can easily cause structural damage to the pile (such as cracking and edge curling). Therefore, assisted driving techniques are required.

[0003] Current pile driving techniques mainly include two approaches: one is pre-drilling, which involves drilling a hole at the target pile location before pile driving to penetrate the hard strata, creating a depth sufficient to fully accommodate the precast pipe pile and reach the required design depth, thus significantly reducing or even eliminating the resistance of the strata to the precast pipe pile. The other is drilling while driving, which involves pre-drilling a drill bit below the pile tip plane of the precast pipe pile, penetrating the strata through the drill bit to achieve simultaneous drilling and pile driving. However, both techniques essentially require drilling or pre-drilling before pile driving; they cannot be implemented after pile driving. Furthermore, the diameter of the drilled hole must be larger than the diameter of the precast pipe pile to effectively reduce or eliminate the driving resistance of the hard strata. If piles are driven without drilling, and the precast pipe piles cannot reach the required depth in hard strata using only impact drilling, the only option is to install drilling equipment inside the precast pipe pile's borehole and drill for soil extraction. The borehole diameter is limited by the inner diameter of the precast pipe pile, and in practice, to avoid damage to the inner wall of the precast pipe pile from the drilling equipment, the borehole diameter is generally smaller than, or even much smaller than, the inner diameter of the precast pipe pile. However, using a smaller borehole significantly reduces the effectiveness of reducing the resistance of driving piles into hard strata.

[0004] In addition, in some working conditions where the geological properties change drastically or are locally abnormal, such as undulating rock surfaces, spheroidal weathering, and uneven thickness of hard interlayers, since geological boreholes generally cannot cover all pile positions, it is difficult to accurately determine whether each pile position needs to be assisted in sinking. If all pile positions are assisted in sinking directly, it may greatly increase unnecessary construction time and costs. It is more reasonable to take necessary assisted sinking measures for pile positions where the actual pile driving depth cannot meet the design requirements. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a pile driving aid device and construction method for precast pipe piles, which can solve the problems described in the background art.

[0006] The technical solution to achieve the objective of this invention is as follows: A pile driving aid device for precast pipe piles, comprising a driving aid assembly, which includes a connecting assembly, a drill rod assembly, a drive box assembly, a reamer assembly, and a main drill bit. One end of the connecting assembly is connected to one end of the drill rod assembly, and the other end is used to connect to external equipment. The reamer assembly is connected to the end of the drive box assembly away from the connecting assembly, and the reamer assembly is located on one side of the drill rod assembly. The drive box assembly is sleeved on the drill rod assembly and can slide along the axial direction of the drill rod assembly. The drive box assembly is used to drive the reamer assembly along the drill rod assembly. The axial sliding of the rod assembly allows the reamer assembly to be housed inside or exposed outside the precast pipe pile's borehole. When exposed, the reamer assembly expands radially along the precast pipe pile so that the reaming drill bit on the reamer assembly is positioned outside the projection plane of the precast pipe pile's inner cavity. This is achieved by driving the reamer assembly downwards from inside the precast pipe pile's borehole to expose it to the outside, or upwards from the outside of the precast pipe pile back into its borehole.

[0007] The drill rod assembly is connected to the main drill bit at the end furthest from the connecting component. The main drill bit is used to drill into the stratum covered by the projection surface of the precast pipe pile's inner cavity. The reamer assembly is used to drill into the stratum outside the projection surface of the precast pipe pile's inner cavity and into the stratum including the projection range of the precast pipe pile's wall. Thus, the main drill bit and the reamer can drill into a borehole with a larger diameter than the inner diameter of the precast pipe pile.

[0008] Furthermore, the sliding range of the drive box assembly along the axial direction of the drill pipe assembly is limited to between a first position and a second position. The first position is the upper limit position, which is the maximum distance the drive box assembly can slide upward, and the second position is the lower limit position, which is the maximum distance the drive box assembly can slide downward.

[0009] Before or just after the drive box assembly slides away from the connecting component to the second position, the reamer assembly is fully exposed outside the precast pipe pile hole. Before the drive box assembly slides from the second position towards the connecting component to the first position, the reamer assembly is fully retracted into the precast pipe pile hole. The drive box assembly is in the first and second positions, and the limiting component on the drill rod assembly limits the drive box assembly.

[0010] Furthermore, the connection components include a lifting lug, a rope, a hose, and a converter. The lifting lug is connected to one end of the rope, and the other end of the rope is connected to the converter. The converter is integrated with both the hose and the drill pipe. The converter is used to connect the hose and the drill pipe. The lifting lug is used to connect to external equipment.

[0011] Furthermore, the drill pipe assembly includes a hollow drill pipe, and an upper chuck assembly and a lower chuck assembly sequentially mounted on the drill pipe along the direction away from the connecting assembly. The upper chuck assembly and the lower chuck assembly are spaced apart and both are located above the main drill bit.

[0012] The chuck assembly includes at least two chuck groups, each chuck group being arranged circumferentially along the drill pipe, and in all chuck groups, at least two chuck groups have an included angle ≥180° between them, such that there is at least one chuck group on each side of the drill pipe.

[0013] The upper card header assembly and the lower card header assembly have the same number of card header groups.

[0014] The upper card head assembly is used for integrated connection with the reamer when it reaches the upper limit position, and the upper and lower head assemblies are used for integrated connection with the reamer when it reaches the lower limit position.

[0015] Furthermore, the chuck assembly includes a chuck cylinder, a chuck spring, a chuck core, and a chuck limiting hole. One end of the chuck cylinder is fixed to the outer surface of the drill rod and is horizontally positioned. The other end of the chuck cylinder has an opening. One end of the chuck spring is fixed to the inner wall of the end of the chuck cylinder connected to the drill rod, and the other end is connected to the chuck core, which extends into the cavity of the chuck cylinder through the opening. The chuck spring is sleeved on one end of the chuck core that extends into the cavity of the chuck cylinder and is fixedly connected to the chuck core. The chuck spring drives the other end of the chuck core to extend out of the cavity of the chuck cylinder or retract into the cavity of the chuck cylinder by extension and retraction. At least one side of the chuck core away from the spring has an arc-shaped profile. A chuck limiting hole is provided on the lower side of the chuck core away from the spring.

[0016] The lower contour of the chuck spring core in the upper chuck assembly is arc-shaped, and the upper contour of the chuck spring core in the lower chuck assembly is arc-shaped. This allows the chuck spring core in the upper chuck assembly, located outside the cavity of the chuck cylinder, to smoothly slide into the reamer assembly while the drive box assembly slides upward along the drill rod assembly, and the reamer assembly, located outside the cavity of the chuck cylinder, to smoothly slide into the reamer assembly while the drive box assembly slides downward along the drill rod assembly, and the reamer assembly, located outside the cavity of the chuck cylinder, to smoothly slide into the reamer assembly.

[0017] Furthermore, the drill pipe assembly also includes a hinge lug assembly, which includes at least two hinge lugs arranged circumferentially along the drill pipe, for example, at equal intervals, and at least two of the hinge lugs have an included angle ≥180° between them, such that there is at least one hinge lug on each side of the drill pipe, and the hinge lugs are integrated with the reamer.

[0018] Furthermore, the drive box integrates a drive box, several limit hydraulic jacks, a pad, several displacement hydraulic jacks, several clutch hydraulic jacks, high-pressure oil pipes, a distributor, a transmission disc, a first gear, and a hydraulic actuator. Both the transmission disc and the hydraulic actuator are installed inside the drive box. The outer ring of the transmission disc is equipped with the first gear, and the hydraulic actuator also has a gear. The gear on the hydraulic actuator meshes with the first gear, thereby connecting the transmission disc and the hydraulic actuator. The hydraulic actuator is connected to an external oil pump. The drill pipe passes through the transmission disc and connects to it.

[0019] The non-output end of the shifting hydraulic jack is vertically fixed to the bottom of the drive box. The number of shifting hydraulic jacks is the same as the number of clutch hydraulic jacks. The output end of the shifting hydraulic jack is connected to the non-output end of the clutch hydraulic jack to drive the clutch hydraulic jack away from or towards the drive box. The number of clutch hydraulic jacks is the same as the number of chuck groups in the upper chuck assembly, so that the clutch hydraulic jacks, the chuck groups of the upper chuck assembly, and the chuck groups of the lower chuck assembly can correspond one-to-one.

[0020] The output end of the clutch hydraulic jack is integrated with the reamer, thereby connecting the drive box and the reamer. The clutch hydraulic jack is located on the outer side of the chuck assembly, away from the drill rod.

[0021] Each limit hydraulic jack is installed inside the drive box cavity and is evenly spaced along the circumference of the drive box. The output end of the limit hydraulic jack extends out of the box and is fixedly connected to a pad located outside the box.

[0022] Limiting hydraulic jacks are used to drive the pad plate closer to or away from the inner wall of the precast pipe pile, thereby fixing the sinking aid component inside the precast pipe pile.

[0023] The output end of the distributor is connected to the limit hydraulic jack, the displacement hydraulic jack, and the clutch hydraulic jack respectively through oil pipes, so as to control the opening and closing of the jacks by supplying or prohibiting the supply of hydraulic oil. The input end of the distributor is connected to the high-pressure oil pipe bundle, and is connected to the external control oil pump through the high-pressure oil pipe bundle, so that the opening and closing of the jacks can be controlled by the control oil pump.

[0024] Furthermore, the reamer integrates a shifting box, an upper connecting rod, a reaming drill bit, a lower connecting rod, a linkage spring, a linkage spring core, a spring core connecting rod, a first connecting protrusion, a second connecting protrusion, and a third connecting protrusion. One end of the shifting box has an opening communicating with a cavity inside the shifting box. The output end of the clutch hydraulic actuator extends into the cavity of the shifting box and connects to it. A U-shaped cavity is excavated at the bottom of the shifting box. Two linkage springs are installed at each end of the U-shaped cavity. One end of each linkage spring is fixed to the bottom wall of the U-shaped cavity, and the other end is connected to a linkage spring core installed inside the U-shaped cavity. The two linkage spring cores are connected by a spring core connecting rod, which is located horizontally within the U-shaped cavity.

[0025] A first connecting protrusion is fixedly connected to the bottom of the shift box, with the first connecting protrusion facing vertically downwards. One end of the upper connecting rod is rotatably connected to the first connecting protrusion, allowing the upper connecting rod to rotate relative to the shift box / first connecting protrusion. The other end of the upper connecting rod is rotatably connected to a second connecting protrusion connected to the reaming drill bit, allowing the upper connecting rod to rotate relative to the reaming drill bit. The second connecting protrusion is horizontally connected to one side of the upper end of the reaming drill bit.

[0026] One end of the lower connecting rod is rotatably connected to a third connecting protrusion on the reaming drill bit, allowing the lower connecting rod to rotate relative to the reaming drill bit. The third connecting protrusion and the second connecting protrusion are mounted on the same side of the reaming drill bit and are parallel and spaced apart. The third connecting protrusion is horizontally connected to one side of the lower end of the reaming drill bit. The other end of the third connecting protrusion is rotatably connected to a hinge lug on the drill rod, allowing the lower connecting rod to rotate relative to the hinge lug / drill rod.

[0027] During the process of the reamer assembly sliding up and down along the axial direction of the drill rod assembly, the upper end of the reamer assembly reaches the position of the upper chuck assembly. The chuck spring core in the upper chuck assembly extends out of the cavity of the chuck cylinder and enters the interior of the upper end of the reamer assembly. The upper end of the reamer assembly reaches the position of the lower chuck assembly. The chuck spring core in the lower chuck assembly extends out of the cavity of the chuck cylinder and enters the interior of the upper end of the reamer assembly.

[0028] Furthermore, it also includes an integrated grouting device. The integrated grouting device and the sinking aid assembly are installed separately. During drilling operations by the main drill bit and the reamer, the integrated grouting device penetrates the precast pipe pile and injects cement mortar as grout into the borehole to fill the inner cavity of the precast pipe pile near the bottom of the borehole, as well as the gap between the borehole diameter and the outer diameter of the precast pipe pile, thereby enhancing the pile's bearing capacity.

[0029] The grouting device assembly includes a high-pressure air pipe, a high-pressure grouting pipe, a steel pipe, an inner soft pad, an air bladder, and an outer soft pad. The high-pressure air pipe passes through the through-hole of the steel pipe. The high-pressure grouting pipe is used to inject grouting fluid, and the high-pressure air pipe is used to inject gas. The steel pipe is vertically fixed to the air bladder and passes through the air bladder. The high-pressure air pipe extends into the air bladder to pump air into it. The high-pressure grouting pipe also passes through the air bladder along with the steel pipe. An inner soft pad is also provided at the joint between the steel pipe and the air bladder. After inflation, the air bladder is tightly attached to the inner wall of the precast pipe pile. An outer soft pad is installed on the outer surface of the air bladder, so that the outer soft pad fits between the air bladder and the precast pipe pile, playing a buffering and protective role.

[0030] A construction method, based on the pile driving aid device for the precast pipe pile, includes the following steps:

[0031] Step 1: Assemble the pile driving aid device, wherein the limiting hydraulic jack, the shifting hydraulic jack, and the clutch hydraulic jack are all in a fully depressurized state, so that the clutch hydraulic jack is above the shifting box and not in contact, the output end of the limiting hydraulic jack is in a fully retracted state, the shifting box and the clamping head assembly of the upper clamping head assembly are at the same height, the clamping head spring core enters the shifting box, the linkage clamping head spring core is inserted into the clamping head limiting hole, and the lower end of the drive box abuts against the top of the lower limiting ring;

[0032] Step 2: Use a dynamic pile driving device to drive the precast pipe pile into the soil layer until it enters a hard soil layer and can no longer penetrate, then remove the dynamic pile driving device.

[0033] Step 3: Use lifting equipment to lift the lifting lugs, thereby lowering the sinking aid component of the pile sinking aid device into the precast pipe pile until the main drill bit contacts the soil surface covered by the projection surface of the precast pipe pile cavity, then stop lowering.

[0034] Step 4: Connect the high-pressure oil pipe to the oil control pump, connect the hose to the mud pump and place it in the mud tank, and pump water into the mud tank to keep the water level in the mud tank stable.

[0035] Step 5: Connect an external oil control pump through a high-pressure oil pipe bundle to control the output end of the limit hydraulic jack to extend until the pad is tightly attached to the inner wall of the precast pipe pile, and maintain the oil delivery pressure of the oil control pump so as to securely fix the drive box inside the precast pipe pile.

[0036] Step 6: Extract the mud from the mud pit outside the precast pipe pile using a mud pump with a filter plug, and then inject the extracted mud back into the precast pipe pile after passing through the hose and drill rod in sequence to maintain the stability of the liquid level inside the precast pipe pile.

[0037] Step 7: Control the hydraulic drive to rotate the drill rod by controlling the oil pump. The drill rod drives the main drill bit to rotate and drill into the soil layer. The mud pump works synchronously to discharge the mud through the hose and drill rod into the mud pit until the top of the drive box touches the upper limit ring.

[0038] Step 8: Lift the drill rod using lifting equipment until it reaches the bottom of the lower limit ring formation drive box on the drill rod, and maintain the current lifting force while simultaneously releasing the pressure of the limit hydraulic jack to retract the output end of the limit hydraulic jack.

[0039] Step 9: Continue to lower the sinking aid component to the soil surface at the bottom of the precast pipe pile, and repeat steps 5-8 until the main drill bit drills into the soil layer of the projection surface of the inner cavity of the precast pipe pile and the reaming drill bit extends out of the precast pipe pile and is located below the bottom plane of the precast pipe pile.

[0040] Step 10: Control the extension of the output end of the shifting hydraulic jack using the oil control pump until the clutch hydraulic jack is fully inserted into the shifting box, and the end of the clutch hydraulic jack furthest from the shifting hydraulic jack contacts the bottom wall of the shifting box cavity. Then stop extending the output end of the shifting hydraulic jack, allowing the linkage card spring core to fully enter the shifting box cavity. Control the extension of the output end of the clutch hydraulic jack using the oil control pump to remove the card spring core from the upper card assembly into the shifting box. Continue controlling the extension of the shifting hydraulic jack using the oil control pump... The output end of the jack extends, causing the shift box to move downwards until it is at the same height as the lower chuck assembly. Then, the downward movement of the shift box stops, the pressure of the clutch hydraulic jack is released, and its output end is fully retracted. The chuck spring in the lower chuck assembly enters the shift box, and the linkage chuck spring in the shift box inserts into the chuck limit hole of the chuck spring in the lower chuck assembly. Then, the pressure of the shift hydraulic jack is released, and its output end is fully retracted. The clutch hydraulic jack returns to the top of the shift box and is no longer in contact with the shift box.

[0041] Step 11: Repeat steps 5-8 until the reamer has drilled to the desired target depth;

[0042] Step 12: Using lifting equipment, lift the drill rod until the bottom of the drive box contacts the lower limit ring, and maintain the current lifting force;

[0043] Step 13: Control the output end of the shift hydraulic jack to extend using the oil control pump until the clutch hydraulic jack is fully inserted into the shift box and the bottom of the clutch hydraulic jack contacts the bottom wall of the shift box cavity. Stop when the clutch hydraulic jack is fully pressed into the bottom wall of the shift box cavity. Next, control the plunger of the clutch hydraulic jack to extend using the oil control pump, and remove the chuck spring from the lower chuck assembly from the shift box. Then, continue to control the output end of the shift hydraulic jack to retract using the oil control pump, causing the shift box to move upward until it is at the same height as the upper chuck assembly. Stop when the pressure of the clutch hydraulic jack is released, and its output end is fully retracted. The chuck spring in the upper chuck assembly enters the shift box, and the clutch chuck spring in the shift box enters the chuck limiting hole of the chuck spring in the upper chuck assembly. Release the pressure of the shift hydraulic jack, and its plunger is fully retracted, so that the clutch hydraulic jack is above the shift box and not in contact.

[0044] Step 14: Release the pressure of the limiting hydraulic jack, retract the plunger, and lift the sinking aid component until the sinking aid component is completely removed from the precast pipe pile.

[0045] Step 15: Continue to drive the precast pipe piles into the soil using dynamic pile driving equipment until it can no longer penetrate, and then remove the dynamic pile driving equipment.

[0046] Step 16: Assemble the grouting unit and connect the high-pressure air pipe and high-pressure grouting pipe to the high-pressure air pump and high-pressure grouting pump on the ground, respectively. Use lifting equipment to lower the assembled grouting unit into the precast pipe pile until the airbag is about twice the pile diameter away from the bottom of the precast pipe pile. Start the high-pressure air pump to inflate the airbag until the outer ring of the airbag is tightly attached to the inner wall of the precast pipe pile through the outer soft pad.

[0047] Step 17: Inject cement mortar into the precast pipe pile using a high-pressure grouting pump and grouting pipe until the grouting pressure suddenly increases or grout emerges from the top of the precast pipe pile. After the cement mortar has initially set, release the pressure of the air bladder and recover the grouting device.

[0048] The beneficial effects of this invention are as follows: This invention solves the problem that when pipe piles are driven into hard soil layers, the required driving depth cannot be met, necessitating the use of pre-drilled holes at the pile tip for further driving. The dynamic pile driving aid device can drill through the inner cavity of the pipe pile to the bottom of the pile after pile driving, and then pre-drill a hole below the pile tip plane. The diameter of the pre-drilled hole is not less than the outer diameter of the pile, thereby greatly reducing or even eliminating the pile driving resistance in hard soil layers, achieving the purpose of effectively assisting driving. After the pile is driven to the required driving depth, the device can be retrieved through the inner cavity of the pipe pile, and grouting is injected into the inner cavity near the bottom of the pipe pile to fill the inner cavity near the bottom and the gap between the pre-drilled hole diameter and the outer diameter of the pile, thereby improving the pile bearing capacity. Attached Figure Description

[0049] Figure 1 A schematic diagram showing a pile-driving aid device placed inside a precast pipe pile with a portion extending outside the precast pipe pile.

[0050] Figure 2 This is a schematic diagram of the drill pipe assembly structure;

[0051] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0052] Figure 4 A front cross-sectional view of the integrated drive box;

[0053] Figure 5 Top view of the integrated drive box;

[0054] Figure 6 A schematic diagram of the integrated structure of the hole expander;

[0055] Figure 7 for Figure 6 Enlarged view of point B in the middle;

[0056] Figure 8 A schematic diagram of the integrated grouting device;

[0057] Figure 9 A schematic diagram showing a pile-driving aid device inserted into a precast pipe pile and just extending out of the precast pipe pile.

[0058] Figure 10 for Figure 9 Enlarged view of point C in the middle;

[0059] In the diagram, 1-lifting lug, 2-rope, 3-hose, 4-converter, 5-high-pressure oil pipe bundle, 6-prefabricated pipe pile, 7-drill rod assembly, 71-upper limit ring, 72-drill rod, 73-lower limit ring, 74-upper chuck assembly, 741-chuck cylinder, 742-chuck spring, 743-chuck spring core, 744-chuck limiting hole, 75-lower chuck assembly, 76-hinged lug assembly, 8-drive box assembly, 81-drive box, 82-limit hydraulic jack, 83-pad plate, 84-shifting hydraulic jack, 85-clutch hydraulic jack, 86-high-pressure oil pipe, 87-oil distributor. 88-Transmission disc, 89-First gear, 810-Hydraulic actuator, 9-Reamer integration, 91-Shift box, 92-Upper connecting rod, 93-Reamer drill bit, 94-Lower connecting rod, 95-Linkage spring, 96-Linkage spring core, 97-Spring core connecting rod, 98-U-shaped cavity, 99-First connecting protrusion, 910-Second connecting protrusion, 911-Third connecting protrusion, 10-Main drill bit, 11-Grouting device integration, 110-High-pressure air pipe, 111-High-pressure grouting pipe, 112-Steel pipe, 113-Inner soft pad, 114-Airbag, 115-Outer soft pad, 12-Pile hole inner wall. Detailed Implementation

[0060] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0061] like Figures 1-10 As shown, a pile driving aid device for a precast pipe pile 6 includes a driving aid assembly. The driving aid assembly includes a connecting assembly, a drill rod assembly 7, a drive box assembly 8, a reamer assembly 9, and a main drill bit 10. One end of the connecting assembly is connected to one end of the drill rod assembly 7, and the other end is used to connect to external equipment. The external equipment is used to lift the pile driving aid device into or out of the pipe hole of the precast pipe pile 6. In actual use, the drill rod assembly 7 is arranged along the axial direction of the precast pipe pile 6 and passes through the precast pipe pile 6. The reamer assembly 9 is connected to the end of the drive box assembly 8 away from the connecting assembly. The reamer assembly 9 is located on one side of the drill rod assembly 7. The drive box assembly 8 is sleeved on the drill rod assembly 7 and can slide along the axial direction of the drill rod assembly 7. The sliding range is limited to a first position and a second position. The first position is the upper limit position, which is the maximum distance the drive box assembly 8 can slide upward. The second position is the lower limit position, which is the maximum distance the drive box assembly 8 can slide downward. The drive box assembly 8 drives the reamer assembly 9 to slide axially along the drill rod assembly 7, so that the reamer assembly 9 is either housed inside or exposed outside the borehole of the precast pipe pile 6. When exposed outside the borehole, the reamer assembly 9 is radially expanded along the precast pipe pile 6, so that the reaming drill bit 93 on the reamer assembly 9 is located outside the projected surface of the inner cavity of the precast pipe pile 6. That is, the drive box assembly 8 drives the reamer assembly 9 to slide downwards from inside the borehole of the precast pipe pile 6 to be exposed outside the precast pipe pile 6, or drives the reamer assembly 9 to slide upwards from outside the precast pipe pile 6 back into the borehole of the precast pipe pile 6.

[0062] Among them, the reamer integrated 9 is an auxiliary drilling tool that works together with the main drill bit 10 to drill into the soil layer so that the diameter of the pilot hole formed by the drilling can be larger than the diameter of the precast pipe pile 6.

[0063] In one alternative implementation, before or just after the drive box integration 8 slides away from the connecting assembly to the second position, the reamer integration 9 is fully exposed outside the borehole of the precast pipe pile 6. Before the drive box integration 8 slides from the second position toward the connecting assembly to the first position, the reamer integration 9 is fully retracted into the borehole of the precast pipe pile 6.

[0064] In an alternative implementation, the drive box integration 8 is in a first position and a second position, and the limiting component on the drill pipe integration 7 is limited to the drive box integration 8.

[0065] The end of the drill pipe assembly 7 furthest from the connecting component is connected to the main drill bit 10, which has a cross-shaped structure.

[0066] The main drill bit 10 is used to drill into the stratum covered by the projection surface of the inner cavity of the precast pipe pile 6, that is, the stratum within the inner diameter of the pipe hole of the precast pipe pile 6. The reamer assembly 9 is used to drill into the stratum outside the projection surface of the inner cavity of the precast pipe pile 6 and the stratum including the projection range of the pipe wall of the precast pipe pile 6, that is, the stratum outside the pipe hole of the precast pipe pile 6. Thus, the main drill bit 10 and the reamer 93 can drill a hole with a larger diameter than the outer diameter of the precast pipe pile 6.

[0067] The connecting assembly includes a lifting lug 1, a rope 2, a hose 3, and a converter 4. The lifting lug 1 is connected to one end of the rope 2, and the other end of the rope 2 is connected to the converter 4. The converter 4 is connected to both the hose 3 and the drill rod assembly 7. The converter 4 connects the hose 3 and the drill rod assembly 7, allowing the liquid formed during drilling to flow upwards through the drill rod assembly 7 to the hose 3 for discharge. The lifting lug 1 can be directly or via a connecting rope connected to external equipment (e.g., a crane), enabling the pile driving aid to be lifted and lowered using external equipment. This allows the pile driving aid to be inserted into and removed from the precast pipe pile 6.

[0068] Rope 2 can be a steel wire rope.

[0069] The drill pipe assembly 7 includes a hollow drill pipe 72, and an upper chuck assembly 74, a lower chuck assembly 75, and a hinge lug assembly 76 sequentially mounted on the drill pipe 72 in a direction away from the connecting assembly. The upper chuck assembly 74, the lower chuck assembly 75, and the hinge lug assembly 76 are spaced apart and are all located above the main drill bit 10.

[0070] The hinge lug assembly 76 includes at least two hinge lugs, each hinge lug being arranged circumferentially along the drill rod 72, for example, being equally spaced, and at least two of the hinge lugs having an included angle ≥180° between them, such that there is at least one hinge lug on each side of the drill rod 72, and the hinge lugs are connected to the reamer integration 9.

[0071] The chuck assembly (upper chuck assembly 74, lower chuck assembly 75) includes at least two chuck groups, each chuck group being arranged circumferentially along the drill pipe 72, for example, at equal intervals, and in all chuck groups, at least two chuck groups have an included angle ≥180° between them, such that there is at least one chuck group on each side of the drill pipe 72. For example, when there are only two chuck groups, one chuck group is symmetrically installed on each of the left and right sides of the drill pipe 72.

[0072] The upper card head assembly 74 and the lower card head assembly 75 have the same number of card head groups.

[0073] The chuck assembly includes a chuck cylinder 741, a chuck spring 742, a chuck core 743, and a chuck limiting hole 744. One end of the chuck cylinder 741 is fixed to the outer surface of the drill rod 72 and is horizontally positioned, while the other end of the chuck cylinder 741 has an opening. One end of the chuck spring 742 is fixed to the inner wall of the end of the chuck cylinder 741 that connects to the drill rod 72, and the other end is connected to the chuck core 743, which extends into the cavity of the chuck cylinder 741 through the opening. The chuck spring 742 is sleeved on one end of the chuck core 743 that extends into the cavity of the chuck cylinder 741 and is fixedly connected to the chuck core 743. The chuck spring 742 drives the other end of the chuck core 743 to extend out of the cavity of the chuck cylinder 741 or retract into the cavity of the chuck cylinder 741 by extension or retraction. The profile of at least one side (upper or lower side) of the end of the chuck core 743 away from the spring is arc-shaped, for example, a 4 / 1 arc. A locking hole 744 is provided on the lower side of the end of the locking spring 743 away from the locking spring 742. For example, in the upper locking assembly 74, a locking hole 744 is provided at the arc-shaped position of the locking spring 743, and in the lower locking assembly 75, a locking hole 744 is provided on the back side of the arc-shaped position of the locking spring 743.

[0074] The lower contour of the chuck spring core 743 in the upper chuck assembly 74 is arc-shaped, and the upper contour of the chuck spring core 743 in the lower chuck assembly 75 is arc-shaped. This allows the chuck spring core 743, located outside the cavity of the chuck cylinder 741 in the upper chuck assembly 74, to be smoothly slid into the reamer integration 9 while the drive box assembly 8 slides upward along the drill rod assembly 7 (i.e., towards the connecting assembly). Similarly, this allows the reamer integration 9 to slide downward along the drill rod assembly 7 (i.e., away from the connecting assembly), and the reamer integration 9 to be smoothly slid into the reamer integration 9 while the drive box assembly 8 slides downward along the drill rod assembly 7 (i.e., away from the connecting assembly).

[0075] As the reamer assembly 9 slides up and down along the axial direction of the drill rod assembly 7, following the drive box assembly 8, its upper end reaches the upper chuck assembly 74. The chuck spring core 743 in the upper chuck assembly 74 extends out of the cavity of the chuck cylinder 741 and enters the interior of the upper end of the reamer assembly 9. Then, the upper end of the reamer assembly 9 reaches the lower chuck assembly 75. The chuck spring core 743 in the lower chuck assembly 75 extends out of the cavity of the chuck cylinder 741 and enters the interior of the upper end of the reamer assembly 9.

[0076] The drive box integration 8 includes a drive box 81, several limit hydraulic jacks 82, a pad 83, several shifting hydraulic jacks 84, several clutch hydraulic jacks 85, a high-pressure oil pipe 86, three oil distributors 87, a transmission disc 88, a first gear 89, and a hydraulic actuator 810. Both the transmission disc 88 and the hydraulic actuator 810 are installed inside the drive box 81. The outer ring of the transmission disc 88 is provided with the first gear 89, and the hydraulic actuator 810 also has a gear. The gear on the hydraulic actuator 810 meshes with the first gear 89, thereby engaging and connecting the transmission disc 88 and the hydraulic actuator 810. The hydraulic actuator 810 is connected to an external control oil pump. The drill rod 72 passes through the transmission disc 88 and connects to it, allowing the control oil pump to drive the hydraulic actuator 810 to rotate. The hydraulic actuator 810 then drives the transmission disc 88 to rotate, which in turn drives the drill rod 72 to rotate. This causes the drill rod 72 to rotate, thus rotating the main drill string connected to its bottom for drilling operations.

[0077] The non-output end of the shifting hydraulic jack 84 is vertically fixed to the bottom end of the drive box 81. The number of shifting hydraulic jacks 84 is the same as the number of clutch hydraulic jacks 85. The output end (i.e., plunger) of the shifting hydraulic jack 84 is connected to the non-output end of the clutch hydraulic jack 85 to drive the clutch hydraulic jack 85 away from or towards the drive box 81. The number of clutch hydraulic jacks 85 is the same as the number of chuck groups in the upper chuck assembly 74, so that the clutch hydraulic jacks 85, the chuck groups of the upper chuck assembly 74, and the chuck groups of the lower chuck assembly 75 can correspond one-to-one. That is, the shifting hydraulic jacks 84 and the chuck groups of the upper chuck assembly 74 correspond one-to-one, the chuck groups of the upper chuck assembly 74 and the chuck groups of the lower chuck assembly 75 correspond one-to-one, and the chuck groups of the clutch hydraulic jacks 85 and the lower chuck assembly 75 also correspond one-to-one.

[0078] The output end (i.e., plunger) of the clutch hydraulic jack 85 is connected to the reamer assembly 9, thereby connecting the drive box assembly 8 to the reamer assembly 9. The clutch hydraulic jack 85 is located on the outer side of the chuck assembly at the end furthest from the drill rod 72.

[0079] Each limit hydraulic jack 82 is installed inside the cavity of the drive box 81 and is evenly spaced along the circumference of the drive box 81. Of course, they can also be spaced out or not spaced out. The output end (i.e., plunger) of the limit hydraulic jack 82 extends out of the box and is fixedly connected to the pad 83 located outside the box.

[0080] The limiting hydraulic jack 82 is used to drive the pad 83 to approach or move away from the inner wall of the precast pipe pile 6, thereby enabling the sinking aid component to be fixed inside the precast pipe pile 6.

[0081] Each limit hydraulic jack 82 is connected to the output end of the distributor 87 via an oil pipe, each displacement hydraulic jack 84 is connected to the output end of another distributor 87 via an oil pipe, and each clutch hydraulic jack 85 is connected to another distributor 87 via an oil pipe. This allows for the control of the opening and closing (i.e., starting operation and stopping operation) of the jacks (limit hydraulic jack 82, displacement hydraulic jack 84, and clutch hydraulic jack 85) by supplying or disabling the supply of hydraulic oil. The input end of the distributor 87 is connected to the high-pressure oil pipe bundle 5, and the three distributors are connected to an external control pump via the high-pressure oil pipe bundle 5, allowing for independent control of the opening and closing of each jack via the control pump.

[0082] In one alternative implementation, there are two limit hydraulic jacks 82, which are symmetrically installed on both sides of the drive box 81.

[0083] The drill rod assembly 7 and drive box assembly 8 work together to form a transmission structure, which allows the reamer assembly 9, used to enlarge the borehole diameter, to slide up and down and be fixed inside the precast pipe pile 6, thereby achieving the purpose of sinking by utilizing the reamer assembly 9. Furthermore, it can smoothly, steadily, and stably drive the reamer assembly 9 to slide and be stably fixed inside the precast pipe pile 6, ensuring that the reamer is at a fixed height position.

[0084] The reamer assembly 9 includes a shift box 91, an upper connecting rod 92, a reaming drill bit 93, a lower connecting rod 94, a linkage spring 95, a linkage spring core 96, a spring core connecting rod 97, a first connecting protrusion 99, a second connecting protrusion 910, and a third connecting protrusion 911. One end of the shift box 91 has an opening that communicates with the cavity inside the shift box 91. The output end (i.e., plunger) of the clutch hydraulic actuator 810 extends into the cavity of the shift box 91 and connects to the shift box 91. A U-shaped cavity 98 is carved into the bottom of the shift box 91. Two linkage springs 95 are installed at each end of the U-shaped cavity 98. One end of each linkage spring 95 is fixed to the bottom wall of the U-shaped cavity 98, and the other end is connected to the linkage spring core 96 installed inside the U-shaped cavity 98. The two linkage spring cores 96 are connected by a spring core connecting rod 97, which is located horizontally within the U-shaped cavity 98.

[0085] A first connecting protrusion 99 is fixedly connected to the bottom (i.e., the outer surface of the bottom wall) of the shift box 91, and the first connecting protrusion 99 is vertically downward. One end of the upper connecting rod 92 is rotatably connected to the first connecting protrusion 99, so that the upper connecting rod 92 can rotate relative to the shift box 91 / first connecting protrusion 99. The other end of the upper connecting rod 92 is rotatably connected to a second connecting protrusion 910 connected to the reaming drill bit 93, so that the upper connecting rod 92 can rotate relative to the reaming drill bit 93. The second connecting protrusion 910 is horizontally fixedly connected to one side of the upper end of the reaming drill bit 93. The second connecting protrusion 910 and the reaming drill bit 93 can be fixedly connected or detachably connected, or they can be an integral structure.

[0086] One end of the lower connecting rod 94 is rotatably connected to a third connecting protrusion 911 connected to the reaming drill bit 93, allowing the lower connecting rod 94 to rotate relative to the reaming drill bit 93. The third connecting protrusion 911 and the second connecting protrusion 910 are mounted on the same side of the reaming drill bit 93 and are arranged parallel to each other. The third connecting protrusion 911 is horizontally fixedly connected to one side of the lower end of the reaming drill bit 93. The third connecting protrusion 911 and the reaming drill bit 93 can be fixedly connected or detachably connected, or they can be an integral structure. The other end of the third connecting protrusion 911 is rotatably connected to a hinge lug on the drill rod 72, allowing the lower connecting rod 94 to rotate relative to the hinge lug / drill rod 72.

[0087] When the chuck spring 743 on the drill pipe assembly 7 enters the cavity of the shift box 91, the clutch hydraulic jack 85 drives the shift box 91 to move upward or downward. The chuck spring 743 presses down the linkage spring 96, and the two linkage springs 96 connected by the spring core connecting rod 97 can also be pressed down, so that the chuck spring 743 completely enters the cavity of the shift box 91. The linkage spring 96 then rebounds under the action of the linkage spring 95 and extends into the chuck limiting hole 744 of the chuck spring 743, realizing the connection between the chuck assembly and the reamer assembly 9. When the chuck spring 743 exits the cavity of the shift box 91, the clutch hydraulic jack 85 drives the shift box 91 to move upward or downward. Under the rebound force formed by the return of the linkage spring 95, which was originally in a compressed state, the linkage spring 96 pops out of the U-shaped cavity 98 again and extends into the cavity of the shift box 91.

[0088] The reaming drill bit 93 is used to drill into the strata outside the projection plane of the inner cavity of the precast pipe pile 6, thereby making the diameter of the drilled hole exceed the diameter of the precast pipe pile 6, which can greatly increase the stratum resistance encountered by the precast pipe pile 6 during penetration.

[0089] In an optional embodiment, the system also includes a grouting unit 11, which is separately installed from the sinking aid assembly. That is, it is a separate assembly from the connecting assembly, drill rod assembly 7, drive box assembly 8, reamer assembly 9, and main drill bit 10. During the drilling operation of the main drill bit 10 and the reamer 93, the grouting unit 11 injects cement mortar as grout into the borehole through the precast pipe pile 6 to fill the inner cavity of the precast pipe pile 6 near the bottom of the borehole, as well as the gap between the borehole diameter and the outer diameter of the precast pipe pile 6, thereby improving the bearing capacity of the pile.

[0090] The grouting unit 11 includes a high-pressure air pipe 110, a high-pressure grouting pipe 111, a steel pipe 112, an inner soft pad 113, an air bladder 114, and an outer soft pad 115. The high-pressure air pipes 110 all pass through the through-holes of the steel pipe 112. The high-pressure grouting pipe 111 is used to inject grouting fluid, and the high-pressure air pipe 110 is used to inject gas (e.g., air). The steel pipe 112 is vertically fixed to and passes through the air bladder 114. The high-pressure air pipe 110 extends into the air bladder 114 to inject air into it. The high-pressure grouting pipe 111 also passes through the air bladder 114 along with the steel pipe 112. An inner soft pad 113 is also provided at the junction of the steel pipe 112 and the air bladder 114. After inflation, the airbag 114 is tightly attached to the inner wall of the precast pipe pile 6. An outer soft pad 115 is installed on the outer surface of the airbag 114 so that the outer soft pad 115 fits between the airbag 114 and the precast pipe pile 6, playing a buffering and protective role.

[0091] Among them, the precast pipe pile 6 is inserted into the inner side of the pile hole 12 formed by the drilling.

[0092] refer to Figure 1 When the shifting box 91 on the drive box integrated 8 and the drive expander integrated 9 reaches the height position of the upper chuck assembly 74, the chuck spring core 743 of the upper chuck assembly 74 pops out and enters the shifting box 91. (Reference) Figure 9 When the shift box 91 on the drive box integrated 8 and the drive expander integrated 9 reaches the height position of the lower chuck assembly 75, the chuck spring core 743 of the lower chuck assembly 75 pops out and enters the shift box 91.

[0093] The present invention also provides a construction method based on the pile driving aid device for the precast pipe pile 6, comprising the following steps:

[0094] Step 1: Assemble the pile driving aid device, wherein the limiting hydraulic jack, the shifting hydraulic jack 84 and the clutch hydraulic jack 85 are all in a fully depressurized state, so that the clutch hydraulic jack 85 is above the shifting box 91 and not in contact, the output end (i.e., the plunger) of the limiting hydraulic jack 82 is in a fully retracted state, the shifting box 91 and the chuck assembly of the upper chuck assembly 74 are at the same height, the chuck spring core 743 enters the shifting box 91, the linkage chuck spring core 743 is inserted into the chuck limiting hole 744, and the lower end of the drive box 81 abuts against the top of the lower limiting ring 73.

[0095] Step 2: Use a dynamic pile driving device to drive the precast pipe pile 6 into the soil layer until it enters a hard soil layer and can no longer penetrate, and then remove the dynamic pile driving device.

[0096] Step 3: Lift the lifting lug 1 using the lifting equipment to lower the sinking aid component of the pile sinking aid device into the precast pipe pile 6 until the main drill bit 10 contacts the soil surface covered by the projection surface of the inner cavity of the precast pipe pile 6, then stop lowering.

[0097] Step 4: Connect the high-pressure oil pipe 86 to the oil control pump, connect the hose 3 to the mud pump and place it in the mud tank, and pump water into the mud tank to keep the water level in the mud tank stable.

[0098] Step 5: Connect an external control oil pump through the high-pressure oil pipe bundle 5 to control the output end (i.e., plunger) of the limit hydraulic jack 82 to extend until the pad 83 is tightly attached to the inner wall of the precast pipe pile 6, and maintain the oil delivery pressure of the control oil pump so as to securely fix the drive box integration 8 inside the precast pipe pile 6.

[0099] Step 6: Extract the mud from the mud pool outside the precast pipe pile 6 using a mud pump with a filter plug, and inject the extracted mud into the precast pipe pile 6 through a pipeline to maintain the stability of the liquid level inside the precast pipe pile 6.

[0100] Step 7: The hydraulic drive 810 is controlled by the oil pump to drive the drill rod 72 to rotate. The drill rod 72 drives the main drill bit 10 to rotate and drill into the soil layer. The mud pump works synchronously to discharge the mud through the hose 3 and the drill rod 72 into the mud pool until the top of the drive box 81 touches the upper limit ring 71.

[0101] Step 8: Lift the drill rod 72 using a lifting device until it reaches the bottom of the formation drive box 81 on the lower limit ring 73 on the drill rod 72, and maintain the current lifting force while simultaneously releasing the pressure of the limit hydraulic jack 82 to retract the output end (i.e., the plunger) of the limit hydraulic jack 82.

[0102] Step 9: Continue to lower the sinking aid component to the soil surface at the bottom of the precast pipe pile 6, and repeat steps 5-8 until the main drill bit 10 drills into the soil layer of the projection surface of the inner cavity of the precast pipe pile 6 and the reaming drill bit 93 extends out of the precast pipe pile 6 and is located below the bottom plane of the precast pipe pile 6.

[0103] Step 10: Control the extension of the output end of the shifting hydraulic jack 84 by the oil pump until the clutch hydraulic jack 85 is fully inserted into the shifting box 91, and the end of the clutch hydraulic jack 85 away from the shifting hydraulic jack 84 contacts the bottom wall of the cavity of the shifting box 91. Then stop extending the output end of the shifting hydraulic jack 84, so that the linkage card spring core is fully inserted into the cavity of the shifting box 91. Control the extension of the output end of the clutch hydraulic jack 85 by the oil pump to remove the card spring core 743 in the upper card assembly 74 from the shifting box 91. Continue to control the extension of the output end of the shifting hydraulic jack 84 by the oil pump to move the shifting box 91 downward until the shifting box 91 is at the same height as the lower card assembly 75. Then stop moving the shifting box 91 downward. The pressure of the clutch hydraulic jack 85 is released, causing its output end to retract completely. The chuck spring 743 in the lower chuck assembly 75 enters the shift box 91, and the linkage chuck spring 743 in the shift box 91 inserts into the chuck limiting hole 744 of the chuck spring 743 in the lower chuck assembly 75. Then, the pressure of the shift hydraulic jack 84 is released, causing its output end to retract completely. The clutch hydraulic jack 85 returns to above the shift box 91 without contacting it.

[0104] Step 11: Repeat steps 5-8 until the reamer 93 has drilled to the desired target depth.

[0105] Step 12: Using lifting equipment, lift the drill rod 72 until the bottom of the drive box 81 contacts the lower limit ring 73, and maintain the current lifting force.

[0106] Step 13: Control the output end of the shifting hydraulic jack 84 to extend using the oil control pump until the clutch hydraulic jack 85 is fully inserted into the shifting box 91 and the bottom of the clutch hydraulic jack 85 contacts the bottom wall of the inner cavity of the shifting box 91. This will allow the linkage chuck spring core 743 to be fully pressed into the bottom wall of the inner cavity of the shifting box 91. Next, control the plunger of the clutch hydraulic jack 85 to extend using the oil control pump, removing the chuck spring core 743 from the lower chuck assembly 75 from the shifting box 91. Then, continue to control the output end of the shifting hydraulic jack 84 to retract using the oil control pump, causing the shifting box 91 to move upwards until it is at the same height as the upper chuck assembly 74, at which point stop. The pressure of the clutch hydraulic jack 85 is released, causing its output end to retract completely. The chuck spring 743 in the upper chuck assembly 74 enters the shift box 91, and the linkage chuck spring 743 in the shift box 91 enters the chuck limiting hole 744 of the chuck spring 743 in the upper chuck assembly 74. The pressure of the shift hydraulic jack 84 is released, causing its plunger to retract completely, so that the clutch hydraulic jack 85 is positioned above the shift box 91 without contact.

[0107] Step 14: Release the pressure of the limit hydraulic jack 82, retract the plunger, and lift the sinking aid component until the sinking aid component is completely removed from the precast pipe pile 6.

[0108] Step 15: Continue to drive the precast pipe pile 6 into the soil layer by using dynamic pile driving equipment until it can no longer penetrate, and then remove the dynamic pile driving equipment.

[0109] Step 16: Assemble the grouting unit 11, and connect the high-pressure air pipe 110 and the high-pressure grouting pipe 111 to the high-pressure air pump and high-pressure grouting pump on the ground, respectively. Use lifting equipment to lower the assembled grouting unit 11 into the precast pipe pile 6 until the airbag 114 is approximately twice the pile diameter (diameter of the precast pipe pile 6) from the bottom of the pile end plane. Start the high-pressure air pump to inflate the airbag 114 until the outer ring of the airbag 114 is tightly attached to the inner wall of the precast pipe pile 6 through the outer soft pad 115.

[0110] Step 17: Inject cement mortar into the precast pipe pile 6 through the high-pressure grouting pump and grouting pipe until the grouting pressure suddenly increases or grout emerges from the top of the precast pipe pile 6. After the cement mortar has initially set, release the pressure of the airbag 114 and recover the grouting device assembly 11.

[0111] This invention solves the problem that when pipe piles are driven into hard soil layers, the required driving depth cannot be met, necessitating the use of pre-drilled holes at the pile tip for assisted driving. The dynamic pile driving aid device can drill through the inner cavity of the pipe pile to the bottom after pile driving, and then drill a hole below the pile tip plane. The diameter of the pre-drilled hole is not less than the outer diameter of the pile, thereby greatly reducing or even eliminating the driving resistance in hard soil layers, achieving effective driving assistance. After the pile reaches the required driving depth, the device can be retrieved through the inner cavity of the pipe pile, and grouting is injected into the inner cavity near the bottom of the pipe pile to fill the gap between the pre-drilled hole diameter and the outer diameter of the pile, thereby enhancing the pile's bearing capacity.

[0112] The embodiments disclosed in this specification are merely illustrative of one aspect of the invention, and the scope of protection of the invention is not limited to these embodiments. Any other functionally equivalent embodiments fall within the scope of protection of the invention. Those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the scope of protection of the claims of this invention.

Claims

1. A pile sinking aid for use in precast tubular pile sinking, characterised in that, The connecting assembly is connected with one end of the drill rod assembly, and the other end is used for being connected with an external device. The reamer assembly is connected with one end of the drive box assembly away from the connecting assembly. The reamer assembly is located on one side of the drill rod assembly. The drive box assembly is sleeved on the drill rod assembly and can slide along the axial direction of the drill rod assembly. The drive box assembly is used for driving the reamer assembly to slide along the axial direction of the drill rod assembly, so that the reamer assembly is accommodated in the pipe hole of the prefabricated pipe pile or exposed outside the pipe hole of the prefabricated pipe pile. When the reamer assembly is exposed outside the pipe hole of the prefabricated pipe pile, the reamer assembly is expanded along the radial direction of the prefabricated pipe pile, so that the reamer bit on the reamer assembly is located outside the projection surface of the inner cavity of the prefabricated pipe pile, that is, the reamer assembly is driven by the drive box assembly to slide downward from the pipe hole of the prefabricated pipe pile to be exposed outside the prefabricated pipe pile, or the reamer assembly is driven to slide upward to be recycled from outside the prefabricated pipe pile into the pipe hole of the prefabricated pipe pile, The drill rod assembly is connected with the main drill bit at one end away from the connecting assembly. The main drill bit is used for drilling into the stratum covered by the projection surface of the inner cavity of the prefabricated pipe pile. The reamer assembly is used for drilling into the stratum outside the projection surface of the inner cavity of the prefabricated pipe pile and the stratum containing the projection range of the pipe wall of the prefabricated pipe pile, so that the main drill bit and the reamer bit can drill into the borehole with a larger diameter than the outer diameter of the prefabricated pipe pile, The sliding range of the drive box assembly along the axial direction of the drill rod assembly is limited between a first position and a second position. The first position is an upward limit position, that is, the maximum distance of the upward sliding of the drive box assembly. The second position is a downward limit position, that is, the maximum distance of the downward sliding of the drive box assembly. Before or just after the drive box assembly slides to the second position in the direction away from the connecting assembly, the reamer assembly is completely exposed outside the pipe hole of the prefabricated pipe pile. Before the drive box assembly slides to the first position in the direction close to the connecting assembly from the second position, the reamer assembly is completely accommodated in the pipe hole of the prefabricated pipe pile. The drive box assembly is located at the first position and the second position. The drill rod assembly is limited by the limiting assembly of the drive box assembly. The connecting assembly comprises an ear, a rope, a hose and a converter. The ear is connected with one end of the rope. The other end of the rope is connected with the converter. The converter is connected with the hose and the drill rod assembly respectively. The converter is used for connecting the hose and the drill rod assembly. The ear is used for being connected with an external device. The drill rod assembly comprises a hollow drill rod, an upper chuck assembly and a lower chuck assembly which are installed on the drill rod in sequence in the direction away from the connecting assembly. The upper chuck assembly and the lower chuck assembly are arranged in a spaced manner and are located above the main drill bit. The chuck assembly comprises at least two chuck groups. Each chuck group is arranged along the circumferential direction of the drill rod. Among all the chuck groups, the included angle between at least two chuck groups is greater than or equal to 180 degrees, so that there is at least one chuck group on each side of the drill rod. The number of chuck groups of the upper chuck assembly and the lower chuck assembly is the same. The upper chuck assembly is used for being connected with the reamer assembly reaching the upward limit position. The lower chuck assembly is used for being connected with the reamer assembly reaching the downward limit position. The chuck assembly comprises a chuck barrel, a chuck spring, a chuck spring core and a chuck limiting hole. One end of the chuck barrel is fixed to the outer surface of the drill rod and arranged horizontally. The other end of the chuck barrel is provided with an opening. One end of the chuck spring is fixed to the inner wall of the end of the chuck barrel connected with the drill rod. The other end of the chuck spring is connected with the chuck spring core which extends into the cavity of the chuck barrel through the opening. The chuck spring is sleeved on one end of the chuck spring core which extends into the cavity of the chuck barrel and is fixedly connected with the chuck spring core. The chuck spring drives the other end of the chuck spring core to extend to the outside of the cavity of the chuck barrel or retract to the inside of the cavity of the chuck barrel. The profile of at least one side of the end of the chuck spring core away from the spring is in an arc shape. The lower side of the end of the chuck spring core away from the spring is provided with the chuck limiting hole, The profile of the lower side of the chuck spring core in the upper chuck assembly is in an arc shape. The profile of the upper side of the chuck spring core in the lower chuck assembly is in an arc shape. During the process that the driving box assembly drives the reamer assembly to slide upward along the drill rod assembly, the end of the chuck spring core in the upper chuck assembly which is located outside the cavity of the chuck barrel can still be located outside the cavity and smoothly slide into the reamer assembly. During the process that the driving box assembly drives the reamer assembly to slide downward along the drill rod assembly, the end of the chuck spring core in the lower chuck assembly which is located outside the cavity of the chuck barrel can still be located outside the cavity and smoothly slide into the reamer assembly.

2. A pile driving aid according to claim 1, c h a r a c t e r i z e d in that The drill rod assembly further comprises a hinged lug assembly. The hinged lug assembly comprises at least two hinged lugs. Each hinged lug is arranged along the ring direction of the drill rod and is arranged at equal intervals. Among all the hinged lugs, the included angle between at least two hinged lugs is greater than or equal to 180°. At least one hinged lug is arranged on each side of the drill rod. The hinged lug is connected with the reamer assembly.

3. A pile driving setting aid for precast piles according to claim 2, characterized in that The driving box assembly comprises a driving box, a plurality of limiting hydraulic jacks, a pad, a plurality of displacement hydraulic jacks, a plurality of clutch hydraulic jacks, a high-pressure oil pipe, a plurality of oil distributors, a transmission disc, a first gear and a hydraulic driver. The transmission disc and the hydraulic driver are both installed in the driving box. The outer ring of the transmission disc is provided with the first gear. The hydraulic driver is also provided with a gear. The gear on the hydraulic driver is engaged with the first gear, so that the transmission disc is engaged with the hydraulic driver. The hydraulic driver is connected with an external oil control pump. The drill rod is connected with the transmission disc by penetrating the transmission disc. The non-output end of the displacement hydraulic jack is fixedly connected with the bottom end of the driving box in a vertical manner. The number of the displacement hydraulic jacks is the same as that of the clutch hydraulic jacks. The output end of the displacement hydraulic jack is connected with the non-output end of the clutch hydraulic jack, so as to drive the clutch hydraulic jack to move away from or close to the driving box. The number of the clutch hydraulic jacks is the same as that of the chuck groups of the upper chuck assembly, so that the clutch hydraulic jacks, the chuck groups of the upper chuck assembly and the chuck groups of the lower chuck assembly can be one-to-one corresponding between each other. The output end of the clutch hydraulic jack is connected with the reamer assembly, so that the driving box assembly is connected with the reamer assembly. The clutch hydraulic jack is located on the outer side of the end of the chuck assembly away from the drill rod. Each limiting hydraulic jack is installed in the cavity of the drive box and is equidistantly arranged along the ring direction of the drive box, and the output end of the limiting hydraulic jack is fixedly connected with the base plate outside the box body, The limiting hydraulic jack is used to drive the base plate to approach or move away from the inner wall of the prefabricated pipe pile, so that the assembly can be fixed inside the prefabricated pipe pile, Each limiting hydraulic jack is connected to the same oil distributor through an oil pipe, each displacement hydraulic jack is connected to another oil distributor through an oil pipe, and each clutch hydraulic jack is connected to another oil distributor through an oil pipe, so as to control the opening and closing of the jack by conveying or inhibiting the conveying of hydraulic oil. The input end of the oil distributor is connected with the high-pressure oil pipe bundle, and the oil distributor is connected with the external oil control pump through the high-pressure oil pipe bundle, so that the three oil distributors are respectively connected with the external oil control pump through the high-pressure oil pipe bundle, so that the opening and closing of each jack can be independently controlled by the oil control pump.

4. A pile driving setting aid for precast pipe piles according to claim 3, characterized in that The reamer assembly comprises a displacement box, an upper connecting rod, a reamer bit, a lower connecting rod, a linkage spring, a linkage spring core, a spring core connecting rod, a first connecting protruding end, a second connecting protruding end and a third connecting protruding end. One end of the displacement box is provided with an opening which is in communication with the cavity in the displacement box. The output end of the clutch hydraulic drive is inserted into the cavity of the displacement box and connected with the displacement box. A U-shaped cavity is formed in the bottom of the displacement box. Two linkage springs are arranged at the two ends of the U-shaped cavity. One end of each linkage spring is fixed to the bottom wall of the U-shaped cavity, and the other end is connected with the linkage spring core installed in the U-shaped cavity. The two linkage spring cores are connected by a spring core connecting rod. The spring core connecting rod is located in the U-shaped cavity and is arranged horizontally. The first connecting protruding end is fixedly connected to the bottom of the displacement box and is arranged vertically downward. One end of the upper connecting rod is rotatably connected with the first connecting protruding end, so that the upper connecting rod can rotate relative to the displacement box / the first connecting protruding end. The other end of the upper connecting rod is rotatably connected with the second connecting protruding end connected to the reamer bit, so that the upper connecting rod can rotate relative to the reamer bit. The second connecting protruding end is horizontally connected to one side of the upper end of the reamer bit. One end of the lower connecting rod is rotatably connected with the third connecting protruding end connected to the reamer bit, so that the lower connecting rod can rotate relative to the reamer bit. The third connecting protruding end and the second connecting protruding end are installed on the same side of the reamer bit and are arranged in parallel and at intervals. The third connecting protruding end is horizontally connected to one side of the lower end of the reamer bit. The other end of the third connecting protruding end is rotatably connected with the hinged ear on the drill rod, so that the lower connecting rod can be rotatably connected with the hinged ear / the drill rod. During the up-and-down sliding of the reamer assembly along the axial direction of the drill rod assembly following the drive box assembly, the upper end of the reamer assembly reaches the upper chuck assembly position, the chuck spring core in the upper chuck assembly protrudes out of the cavity of the chuck barrel and enters the inside of the upper end of the reamer assembly, the upper end of the reamer assembly reaches the lower chuck assembly position, and the chuck spring core in the lower chuck assembly protrudes out of the cavity of the chuck barrel and enters the inside of the upper end of the reamer assembly.

5. A pile driving setting aid for precast pipe piles according to claim 4, characterized in that Also include grouting device integration, grouting device integration and sinking assembly for split installation, grouting device integration for main drill bit and reamer bit into the formation drilling operation, grouting device integration through the prefabricated pipe pile into the borehole injection as grouting liquid cement mortar, to fill the prefabricated pipe pile near the bottom of the borehole cavity, and the hole diameter and the outer diameter of the gap between the prefabricated pipe pile pile, to enhance the role of pile bearing capacity, Grouting device integration includes high pressure gas pipe, high pressure grouting pipe, steel pipe, inner soft pad, air bag and outer soft pad, high pressure gas pipe through the through hole of steel pipe, high pressure grouting pipe for injection of grouting liquid, high pressure gas pipe for injection of gas, steel pipe is vertically fixed on the air bag and through the air bag, high pressure gas pipe into the air bag, in order to into the air bag, high pressure grouting pipe also through the air bag, the combination of steel pipe and air bag is also provided with inner soft pad, air bag after inflation close to the inner wall of the prefabricated pipe pile, air bag close to the outer surface of the installation of outer soft pad, so that the outer soft pad between the air bag and the prefabricated pipe pile, play the role of enhanced sealing.

6. A construction method, characterized by, Based on the pile sinking device for prefabricated pipe pile as claimed in claim 5, comprising the following steps: Step 1: the assembly of the pile sinking device, wherein the limiting hydraulic jack, displacement hydraulic jack and clutch hydraulic jack are in the complete pressure relief state, so that the clutch hydraulic jack is located above the displacement box and has no contact, the output end of the limiting hydraulic jack is in the complete recovery state, the displacement box and the jaw group of the upper jaw assembly are in the same height position, the jaw core enters the displacement box, the linkage jaw core is inserted into the jaw limiting hole, and the lower end of the drive box abuts against the top end of the lower limiting ring; Step 2: using power pile sinking equipment to sink the prefabricated pipe pile into the soil layer until it cannot continue to penetrate into the hard soil layer, and removing the power pile sinking equipment; Step 3: lifting the lifting lug by hoisting equipment, so as to lower the sinking assembly of the pile sinking device into the prefabricated pipe pile until the main drill bit contacts the soil surface covered by the soil layer of the projection surface of the inner cavity of the prefabricated pipe pile, and then stopping lowering; Step 4: connecting to the oil control pump through the high pressure oil pipe, connecting the hose to the mud pump, and putting it into the mud pool, and pumping water into the mud pool through the water pump to keep the water level in the mud pool stable; Step 5: connecting the external oil control pump through the high pressure oil pipe bundle to control the output end of the limiting hydraulic jack to extend until the pad closely adheres to the inner wall of the prefabricated pipe pile, and maintaining the oil delivery pressure of the oil control pump so as to stably fix the drive box integration in the prefabricated pipe pile; Step 6: extracting the mud liquid in the mud pool outside the prefabricated pipe pile through the mud pump with filter plug, and injecting the extracted mud liquid into the prefabricated pipe pile through the pipeline to maintain the stability of the liquid level in the prefabricated pipe pile; Step 7: controlling the hydraulic drive to drive the drill pipe to rotate through the oil control pump, and rotating the drill pipe to drill into the soil layer, and synchronously working the mud pump to discharge the mud liquid into the mud pool through the hose and the drill pipe, until the top of the drive box abuts against the upper limiting ring. Step 8: lifting the drill pipe by the lifting equipment until the lower limit ring on the drill pipe contacts the bottom of the drive box, and keeping the current lifting force, simultaneously unloading the pressure of the limiting hydraulic jack to recover the output end of the limiting hydraulic jack; Step 9: continuing to lower the sinking assisting assembly to the soil surface at the bottom of the precast pipe pile, and repeating steps 5-8 until the main drill bit drills into the soil layer of the projected surface of the precast pipe pile inner cavity and the reamer extends out of the precast pipe pile and is below the bottom plane of the precast pipe pile; Step 10: controlling the output end of the displacement hydraulic jack to extend by the control oil pump until the clutch hydraulic jack is completely in the displacement box, and the end of the clutch hydraulic jack away from the displacement hydraulic jack contacts the bottom wall of the displacement box cavity, then stopping the extension of the output end of the displacement hydraulic jack, so that the linkage collar spring is completely in the cavity of the displacement box, controlling the output end of the clutch hydraulic jack to extend by the control oil pump, the collar spring in the upper collar assembly exits the displacement box, continuing to control the output end of the displacement hydraulic jack to extend by the control oil pump, so that the displacement box moves down until the displacement box is at the same height position as the lower collar assembly, then stopping the displacement box from moving down, unloading the pressure of the clutch hydraulic jack to completely recover its output end, the collar spring in the lower collar assembly enters the displacement box, the linkage collar spring in the displacement box is inserted into the collar limiting hole of the collar spring in the lower collar assembly, and then the pressure of the displacement hydraulic jack is unloaded to completely recover its output end, and the clutch hydraulic jack is again above the displacement box without contact; Step 11: repeating steps 5-8 until the reamer drills to the required target depth; Step 12: lifting the drill pipe by the lifting equipment until the bottom of the drive box contacts the lower limit ring, and keeping the current lifting force; Step 13: controlling the output end of the displacement hydraulic jack to extend by the control oil pump until the clutch hydraulic jack is completely in the displacement box, and the bottom of the clutch hydraulic jack contacts the bottom wall of the displacement box cavity to stop, so that the linkage collar spring is completely pressed into the bottom wall of the displacement box cavity, then controlling the plunger of the clutch hydraulic jack to extend by the control oil pump to make the collar spring in the lower collar assembly exit the displacement box, then continuing to control the output end of the displacement hydraulic jack to retract by the control oil pump to move the displacement box up until the displacement box is at the same height position as the upper collar assembly, then stopping, unloading the pressure of the clutch hydraulic jack to completely recover its output end, the collar spring in the upper collar assembly enters the displacement box, the linkage collar spring in the displacement box enters the collar limiting hole of the collar spring in the upper collar assembly, the pressure of the displacement hydraulic jack is unloaded to completely recover its plunger, so that the clutch hydraulic jack is above the displacement box without contact; Step 14: unloading the pressure of the limiting hydraulic jack, recovering the plunger, and lifting the sinking assisting assembly until the sinking assisting assembly is completely removed out of the precast pipe pile; Step 15: continuing to sink the precast pipe pile into the soil layer by the power pile driving equipment in the power pile driving mode until it cannot continue to penetrate, and removing the power pile driving equipment; Step 16: Assemble the grouting device, connect the high-pressure air pipe and the high-pressure grouting pipe to the high-pressure air pump and the high-pressure grouting pump on the ground respectively, lower the assembled grouting device into the precast pipe pile by lifting equipment until the distance between the air bag and the pile end plane of the lower part of the precast pipe pile is 2 times the pile diameter, start the high-pressure air pump to inflate the air bag until the outer ring side of the air bag tightly adheres to the inner wall of the precast pipe pile through the outer soft pad; Step 17: Inject cement mortar into the precast pipe pile through the high-pressure grouting pump and the grouting pipe until the grouting pressure suddenly increases or the grouting on the top of the precast pipe pile ends. After the cement mortar is initially cured, the air bag pressure is released and the grouting device is recovered.

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