Pre-cast pipe pile hard ground sinking and bottom expanding integrated construction device and method

Abstract

The application belongs to the technical field of prefabricated pipe pile construction equipment, in particular to a prefabricated pipe pile hard stratum sinking-expanding bottom integrated construction device and method, an external surface of a drill bit rod near one end of a roller bit is provided with a sinking-expanding hole mechanism, a controller is electrically connected with an action part and the sinking-expanding hole mechanism; the sinking-expanding hole mechanism further comprises a hole expanding mechanism for expanding the bottom of the prefabricated pipe pile, a centering guide mechanism for guiding and centering, and a sinking pipe assisting mechanism for sinking; through the sinking-expanding hole mechanism composed of a supporting ring, a first bearing, a second bearing, a supporting plate, a hole expanding mechanism, a centering guide mechanism and a sinking pipe assisting mechanism, the sinking-expanding hole mechanism, the second bearing, the supporting plate and the hole expanding mechanism installed on the drill bit rod are integrated into the same device for hole sinking, bottom expanding, drill bit rod guiding and centering, thereby reducing processes and improving efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of precast pipe pile construction equipment, specifically relating to an integrated construction device and method for aiding sinking and expanding the base of precast pipe piles in hard strata. Background Technology

[0002] Precast pipe piles are widely used in various geotechnical foundation engineering projects, including buildings, municipal works, bridges, and ports, due to their advantages such as high bearing capacity, fast construction speed, stable quality, and low cost. Conventional precast pipe pile construction often employs hammer driving and static pressure methods, which are well-suited for soft soils such as ordinary soft soil and silty clay. However, they present significant challenges in hard soils such as weathered rock, dense gravel layers, and hard plastic clay layers. Hard soils are characterized by high hardness, high density, and extremely strong end-pile resistance. Conventional pile driving techniques are prone to problems such as difficulty in driving precast pipe piles, inability to sink the pile to the correct depth, pile tip suspension, and excessive verticality deviation, severely impacting the quality and bearing capacity of the pile foundation construction. To solve the problem of pile driving in hard soil, existing construction techniques generally adopt a step-by-step construction process of first drilling, then driving the pile, and then expanding the pile end. The drilling rig first drills holes at the pile location to break up the hard soil layer, which assists in the sinking of the pipe pile. At the same time, the pile end is expanded to increase the bearing area of ​​the pile end and improve the vertical bearing capacity of the pile foundation.

[0003] However, existing construction equipment and processes have many significant drawbacks. First, the processes of pre-drilling, pile driving assistance, and pile end enlargement are independent of each other, requiring separate drilling equipment, pile driving auxiliary equipment, and special enlargement equipment to be used on-site in multiple phases. This results in frequent equipment hoisting, relocation, and debugging, cumbersome construction procedures, significantly extending the pile foundation construction cycle, low construction efficiency, and a substantial increase in equipment rental, labor, and energy costs. Second, the multi-equipment, multi-phase construction requires repeated alignment and calibration of the pile position, which can easily lead to cumulative positioning deviations. This can cause misalignment between the pre-drilling / enlargement positions and the center of the pipe pile, disrupting the coaxiality of the pile foundation construction. This not only reduces the effectiveness of pile end enlargement and weakens the pile foundation's bearing capacity but also easily causes quality hazards such as pipe pile misalignment and pile damage, making it difficult to guarantee construction accuracy.

[0004] Furthermore, existing underreaming and sinking aid equipment has limited functionality and lacks a supporting centering and guiding structure. The drill bit and drill rod are prone to swaying and shifting during drilling and underreaming in hard strata, further exacerbating the verticality deviation of the pile hole and failing to meet the requirements of high-precision pile foundation construction. Simultaneously, during construction, the rotation of the drill rod and the underreaming and sinking aid structure are prone to motion interference, resulting in poor structural adaptability and difficulty in achieving synchronous operation. This fails to fundamentally solve the industry pain points of low efficiency, poor precision, and insufficient construction stability in precast pipe pile construction in hard strata.

[0005] In summary, there is an urgent need for a construction device that integrates functions such as pre-drilling and sinking assistance, pile end expansion, and guiding and centering, in order to simplify construction procedures, improve construction accuracy and efficiency, and meet the high-quality construction requirements of precast pipe piles in hard strata. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing an integrated construction device and method for aiding settlement and widening the base of precast pipe piles in hard strata. The specific technical solution is as follows:

[0007] An integrated construction device for sinking and enlarging precast pipe piles in hard strata includes an actuating unit. The actuating unit's power unit is equipped with a power drill rod. Several extension drill rods are screwed onto the lower end of the power drill rod. A drill bit rod is screwed onto the lower end of each extension drill rod. A roller cone drill bit is fixed to the lower end of each drill bit rod. A precast pipe pile is installed outside the drill bit rod and is driven into the soil layer. A sinking and enlarging mechanism is installed on the outer surface of the drill bit rod near the roller cone drill bit. The controller is electrically connected to the actuating unit and the sinking and enlarging mechanism.

[0008] The sinking and reaming mechanism includes a support ring fitted around the drill rod, a first bearing installed inside the support ring, and the inner ring of the first bearing fixed outside the drill rod. A second bearing is located directly below the support ring, and a support plate is welded to the inner ring of the second bearing. The support plate abuts against the outer wall of the drill rod. The sinking and reaming mechanism also includes a reaming mechanism for expanding the bottom of the precast pipe pile, a centering and guiding mechanism for guiding and centering, and a sinking tube assisting mechanism for sinking. The reaming mechanism is installed on the support ring, the second bearing, the support plate, and the drill rod. The sinking tube assisting mechanism is installed on the second bearing, and the centering and guiding mechanism is installed on the support ring.

[0009] The hole-reaming mechanism includes a blade angle-adjusting oil pump fixedly mounted on the upper surface of the support ring, a first hydraulic cylinder for adjustment installed between the support ring and the support plate, a first hydraulic oil pipe installed between the blade angle-adjusting oil pump and the first hydraulic cylinder, a hole-reaming blade welded to the outer surface of the drill rod at the lower part of the support plate, the hole-reaming blade being rotatably mounted to the rotating shaft frame, the upper end of the angle-adjusting connecting rod being rotatably mounted on the outer ring surface of the second bearing, and the lower end of the angle-adjusting connecting rod being axially connected to the swing arm fixed on the rotating shaft frame;

[0010] The cylinder body of the first hydraulic cylinder is fixed to the lower surface of the support ring, and the telescopic end is fixed to the upper surface of the second bearing. When the first hydraulic cylinder extends, it pushes the second bearing to rise along the drill rod axis, and pulls the rotating shaft frame to rotate around the hinge point between it and the reaming blade through the angle adjustment link, thereby realizing the unfolding of the reaming blade.

[0011] A rotating shaft frame is rotatably mounted inside the enlarged aperture blade. An angle adjustment link is rotatably mounted at one end of the rotating shaft frame near the enlarged aperture blade. The upper end of the angle adjustment link is rotatably mounted on the outer ring surface of the second bearing. A limiting baffle for limiting the rotation of the rotating shaft frame to 45 degrees is welded to the upper part of the enlarged aperture blade. An angle sensor for detecting the angle is installed on the inner surface of the rotating shaft frame. Both the blade angle adjustment oil pump and the angle sensor are electrically connected to the controller.

[0012] The angle-adjusting connecting rod, the expanding wing, and the rotating shaft frame are all arranged in a ring array of three. The free end of the rotating shaft frame is arc-shaped and is provided with a cutting blade. The surface of the free end of the rotating shaft frame is inlaid with wear-resistant alloy teeth.

[0013] The centering and guiding mechanism includes a centering oil pump mounted on the upper surface of a support ring, a second hydraulic cylinder welded into a hole on the outer side of the support ring, a second hydraulic oil pipe installed between the centering oil pump and the second hydraulic cylinder, a first pressure sensor for detecting pressure fixed at the telescopic end of the second hydraulic cylinder, a guide wheel mounted at the end of the first pressure sensor, seven second hydraulic cylinders arranged in a circular array, and both the centering oil pump and the first pressure sensor are electrically connected to the controller.

[0014] The tube sinking assist mechanism includes a tube sinking oil pump mounted on the upper surface of the inner ring of the second bearing, a third hydraulic cylinder welded to the upper surface of the inner ring of the second bearing, a third hydraulic oil pipe installed between the tube sinking oil pump and the third hydraulic cylinder, a second pressure sensor for detecting pressure fixed at the telescopic end of the third hydraulic cylinder, an alloy anti-slip pad installed at the end of the second pressure sensor, and nine alloy anti-slip pads arranged in a ring array. The tube sinking oil pump and the second pressure sensor are both electrically connected to the controller.

[0015] The actuating unit includes a connector rotatably mounted on the upper end of the power drill rod. A motor is fixed to the upper end of the connector, and the output shaft of the motor is fixed to the upper end of the power drill rod. A hydraulic cylinder is mounted on the upper end of the motor. A sewage pump is mounted on the side of the connector, and the inlet end of the sewage pump is connected to the power drill rod. The motor, hydraulic cylinder, and sewage pump are all electrically connected to the controller.

[0016] The upper end of the precast pipe pile is fitted with a filter pipe for liquid reflux, and the lower end of the filter pipe is welded with a steel needle. The filter pipe has a hyperbolic tubular structure and the pore size of the filter pipe is 0.1 mesh.

[0017] The controller includes a main control module, a data acquisition module, a hydraulic control module, a motor drive module, a signal feedback module, an alarm protection module, and a human-machine interaction module.

[0018] The data acquisition module is electrically connected to the tilt sensor, the first pressure sensor, and the second pressure sensor respectively, and is used to collect construction condition data such as hole expansion angle, centering and tightening pressure, and tube extrusion pressure in real time, and transmit the collected data to the main control module.

[0019] The hydraulic control module is electrically connected to the vane angle adjustment oil pump, the centering oil pump, and the sinking pipe oil pump, respectively. It is used to receive instructions from the main control module and precisely control the start and stop of each oil pump, the oil pressure output, and the extension and retraction of the oil cylinder, so as to realize the automated operation of stepless adjustment of hole expansion angle, drill rod centering and guidance, and pipe pile sinking and locking.

[0020] The motor drive module is electrically connected to the motor, hydraulic cylinder and sewage pump of the actuating unit, and is used to control the drilling speed, drilling pressure and sewage operation start and stop, and is adapted to the adaptive drilling mode of different strata such as soft soil, hard soil and rock.

[0021] The signal feedback module is used to receive real-time operating signals from each sensor, form a closed-loop control logic, and correct the action parameters of each actuator in real time according to the angle deviation, pressure difference, and mechanism operating status to ensure construction accuracy.

[0022] The alarm protection module has built-in warning programs for pressure over-limit, angle deviation, mechanism jamming, and equipment overload. When the construction parameters are detected to exceed the preset threshold, the shutdown protection is automatically triggered and an audible and visual alarm is issued, realizing interlock protection for multi-mechanism operation and preventing equipment damage and defects in pile foundation construction quality.

[0023] The human-machine interaction module is used for parameter preset, real-time display of working conditions, and data storage and export of construction data. It can pre-enter construction parameters such as drilling speed, drilling pressure, hole enlargement angle, and pile driving pressure, and at the same time display the equipment operating status and stratum construction conditions in real time, supporting iterative adjustment of parameters for segmented construction of ultra-long piles.

[0024] The method for constructing an integrated precast pipe pile sinking-base enlargement method in hard strata is as follows:

[0025] Step 1: Pre-treatment for pile positioning. The precast pipe piles are smoothly hoisted to the construction site using hoisting equipment. The verticality of the precast pipe piles is adjusted using a total station and a verticality measuring instrument, controlling the verticality deviation of the pile body to ≤0.5%. After adjustment, the precast pipe piles are initially driven into the soil using pile driving equipment, with the penetration depth controlled at 0.8-1.2m, to achieve temporary fixation of the pile body and prevent pile displacement during subsequent construction. At the same time, a hyperbolic filter pipe is sleeved on the upper end of the precast pipe pile. The filter pipe is fixed by steel needles at the bottom, and the 0.1 mesh pores are used to filter and return construction slurry and sewage, preventing soil impurities from entering the inner cavity of the pile.

[0026] Step 2: The integrated device is positioned and fixed. The assembled sinking-expansion integrated construction device is placed into the cavity of the precast pipe pile. The centering and guiding mechanism is activated by the controller. The centering oil pump drives the second hydraulic cylinder to extend, which drives the end guide wheel to fit against the inner wall of the precast pipe pile. The seven second hydraulic cylinders arranged in a ring array synchronously and adaptively tighten. The first pressure sensor monitors the tightening pressure in real time and adjusts the extension and retraction of the cylinders accordingly. This achieves the overall centering and guiding of the drill rod, locks the construction posture of the device, and prevents the drill rod from eccentrically shaking during drilling and hole expansion.

[0027] Step 3: Adaptive pilot hole drilling. The controller activates the actuator, driving the motor to rotate the power drill rod, extension drill rod, and the roller cone drill bit at the bottom of the drill bit rod. Simultaneously, the hydraulic cylinder outputs constant drilling pressure, adaptively adjusting construction parameters according to the geological conditions: low drilling pressure and high rotation speed mode is used for soft soil layers, high drilling pressure and low rotation speed mode is used for hard soil layers, and the impact-rotation composite drilling mode is switched for rock strata. Pilot hole construction continues in the stratum below the precast pipe pile end, with an over-drilling depth of 0.3-0.5m reserved in combination with the designed drilling depth of the pile end to ensure sufficient drilling of the bearing layer at the pile end. During the drilling process, the sewage pump is activated to discharge the slag and mud from the hole through the hollow structure of the power drill rod, extension drill rod, and drill bit rod, ensuring the cleanliness of the hole.

[0028] Step 4: Stepless Adjustable Enlarging of the Pile End. After the pilot hole reaches the preset depth, keep the drill rod stationary in the center. Start the reaming mechanism through the controller. The vane angle adjustment oil pump drives the first hydraulic cylinder to extend through the first hydraulic oil pipe, driving the second bearing vertical lifter. With the help of the angle adjustment linkage, the shaft frame and the reaming vane slowly unfold outward. Relying on the limit baffle, the stepless angle adjustment from 0 to 45 degrees is achieved. At the same time, the tilt sensor collects the rotation angle data of the shaft frame in real time and feeds it back to the controller to accurately control the reaming opening. The reaming diameter is strictly controlled to be 1.2-1.5 times the outer diameter of the precast pipe pile. The reaming vane with three sets of ring arrays and the end cutting blades and wear-resistant alloy teeth cut and enlarge the soil and rock layers at the pile end to form a regular pile end enlarged head structure, which improves the bearing capacity of the pipe pile end.

[0029] Step 5: Reset and retract the hole-expanding mechanism. After the pile end expansion construction is completed, the controller reverses the control of the blade angle adjustment oil pump to drive the first hydraulic cylinder to reset. This drives the angle adjustment linkage to pull the shaft frame and the hole-expanding blades inward and completely retract them to the preset position outside the drill rod. This eliminates the scratching effect of the hole-expanding structure on the external soil and ensures that the drill rod can be lifted smoothly. At the same time, the tilt sensor feeds back the reset signal to avoid residual opening angle of the blades causing equipment wear and pile wall damage.

[0030] Step Six: Hydraulic-assisted pile driving construction. After the hole-expanding mechanism is fully reset, the pipe-driving assist mechanism is activated. The pipe-driving oil pump drives the third hydraulic cylinder to extend, causing the end alloy anti-slip pad to tightly press against the inner wall of the precast pipe pile. The second pressure sensor monitors the pressing force in real time and provides feedback for adjustment, ensuring that the nine sets of annular array alloy anti-slip pads are evenly stressed, thus achieving a stable lock between the hole-expanding mechanism and the precast pipe pile. Subsequently, relying on the drilling rod's lowering power, the precast pipe pile is driven down as a whole. With the help of the pile driving equipment, a second driving is carried out to accurately drive the precast pipe pile into the design elevation, so that the pile end is completely embedded in the pile end enlarged head area, solving the problems of difficult and incomplete pile driving in hard strata.

[0031] Step 7: Pile end gap reinforcement treatment. After the pile driving construction is completed, according to the soil quality and bearing capacity design requirements, selective post-grouting construction is carried out at the pile end. Cement grout is injected into the gap between the pile end enlarged head and the bottom of the pile body through the reserved grouting channel in the pile to fill the gap in the hole, solidify the loose soil layer, strengthen the integrity of the bearing layer at the pile end, and greatly improve the vertical compressive and tensile bearing capacity of the precast pipe pile. After the grouting is completed, static curing is carried out to ensure that the grout solidifies and forms.

[0032] Step 8: Long pile segmented cyclic construction. For the construction of ultra-long precast pipe piles, if the single pile driving depth cannot reach the design elevation, repeat steps 2 to 6 to complete the secondary centering and guidance, deep drilling, and bottom enlargement to assist sinking operations in sequence. The pipe piles are driven down segment by segment until the pile body reaches the design construction elevation. The construction status is monitored in real time by sensors throughout the process to ensure that the verticality of segmented construction and the pile driving accuracy meet the standards.

[0033] Step Nine: The entire device is recycled and reused. After all construction procedures are completed, each hydraulic mechanism is shut down in sequence, and the centering and guiding mechanism and the pipe sinking assist mechanism are reset so that the guide wheel and alloy anti-slip pad are detached from the inner wall of the pipe pile. All actuators are fully retracted and reset. The overall length of the central drill rod is reduced to decrease the overall volume of the device. The integrated device is then lifted out of the precast pipe pile cavity smoothly using hoisting equipment. Subsequently, vulnerable parts such as the roller cone drill bit, wear-resistant alloy teeth, hydraulic cylinder, and sensors are inspected, cleaned, maintained, and replaced. After successful debugging, it can be reused for subsequent pile foundation construction.

[0034] This invention also includes detailed rules for precise control of construction parameters, equipment linkage regulation, and working condition adaptation, as follows:

[0035] The multi-mechanism linkage electrical control details show that the entire device is centrally controlled by a controller to achieve coordinated operation and interlocking protection among the various mechanisms: When the hole reaming mechanism is operating, the centering and guiding mechanism maintains a stable pressure and centering state, locks the drill rod's degree of freedom of deviation, and prohibits the sinking tube assist mechanism from operating; when the pile sinking assist operation is underway, the hole reaming blades remain fully retracted and locked to avoid scraping against the pile wall soil; each pressure sensor and tilt sensor collects working condition data in real time to form a closed-loop feedback control. When pressure exceeds the standard, angle deviation, or mechanism jamming is detected, the controller automatically stops the machine and alarms to prevent equipment damage and construction quality problems;

[0036] Adaptive drilling parameter control relies on real-time monitoring of formation hardness and drilling resistance data during construction. The controller automatically matches the optimal construction parameters to precisely adapt to different formations: In soft soil conditions, a low drilling pressure of 0.2-0.5MPa and a high drilling speed of 80-120r / min are used to improve drilling efficiency; in hard soil conditions, a high drilling pressure of 0.8-1.2MPa and a low drilling speed of 30-60r / min are used to avoid drill bit slippage and wear; in rock conditions, the impact-rotation composite working mode is switched, using high-frequency impact combined with low-speed rotation to break the rock layer, adapting to the requirements of borehole enlargement in hard formations.

[0037] The detailed rules for precision control during the enlargement construction include: monitoring the rotation angle of the shaft frame in real time using an inclination sensor throughout the enlargement operation, with the angle adjustment accuracy controlled within ±0.5 degrees and the enlargement diameter error controlled within ±20mm; the three sets of enlargement blades are synchronously and symmetrically deployed to ensure that the pile end enlargement head has a regular circular structure, eliminating problems such as eccentric enlargement and insufficient local enlargement; the limit baffle strictly limits the maximum rotation angle of the shaft frame to 45 degrees to avoid excessive enlargement causing soil collapse and instability of the pile end structure;

[0038] The detailed rules for pressure control in the sinking assistance mechanism are as follows: When the sinking assistance mechanism is working, the second pressure sensor monitors the hydraulic cylinder extrusion pressure in real time and controls the extrusion pressure stably at 1.0-1.5MPa to ensure that the alloy anti-slip pad is firmly attached to the pile wall and will not squeeze or damage the inner wall of the precast pipe pile; the pressure difference of the seven sets of centering guide cylinders is controlled within ±0.1MPa to ensure that the drill rod is always on the central axis of the pile body, ensuring the verticality of the pile sinking and the uniformity of the force.

[0039] The detailed rules for equipment recycling, maintenance, and reuse stipulate that all movable structures are reset without residue after construction, and the reaming vanes, guide wheels, and anti-slip pads are completely housed and fitted to the main body of the mechanism without any protruding structures. During disassembly and inspection of the device, the wear of the roller cone drill bit and wear-resistant alloy teeth is the focus of inspection, and any parts with excessive wear are replaced immediately. Hydraulic pipelines and bearing structures are regularly lubricated, and sensors are regularly calibrated to ensure the stability and accuracy of the equipment for repeated use and reduce the cost of construction equipment.

[0040] The mud filtration and environmental protection construction details stipulate that the mud and sewage generated during construction are filtered back through the filter pipe at the top of the precast pipe pile. The 0.1 mesh high-precision pores can intercept solid impurities such as slag and gravel. The filtered clean water can be recycled, and the impurities are collected and treated in a centralized manner to avoid construction slag from polluting the construction site and to prevent impurities from entering the pile hole and affecting the quality of pile foundation construction.

[0041] Compared with the prior art, the beneficial effects of the present invention are:

[0042] 1. A sinking and reaming mechanism consisting of a support ring, a first bearing, a second bearing, a support plate, a reaming mechanism, a centering and guiding mechanism, and a sinking tube assist mechanism is used. The support ring is rotatably mounted on the outside of the drill rod via the first bearing. The reaming mechanism mounted on the support ring, the second bearing, the support plate, and the drill rod connects the second bearing to the support ring through the reaming mechanism. The reaming mechanism is used for reaming the bottom, the sinking tube assist mechanism mounted on the second bearing is used for sinking assistance, and the centering and guiding mechanism mounted on the support ring is used for guiding and centering the drill rod. The sinking assistance, bottom reaming, drill rod guidance, and centering functions are integrated into a single device, reducing processes and improving efficiency.

[0043] 2. The hole-expanding mechanism consists of a vane angle-adjusting oil pump, a first hydraulic oil pipe, a first hydraulic oil cylinder, an angle-adjusting connecting rod, a hole-expanding vane, a rotating shaft frame, an tilt sensor, and a limit baffle. When the vane angle-adjusting oil pump is energized, it drives the first hydraulic oil cylinder to extend and retract, causing the extension end of the first hydraulic oil cylinder to lift and lower the second bearing. When the second bearing rises, it drives the rotating shaft frame to rotate upward through the angle-adjusting connecting rod. The limit baffle is used to limit the rotation of the rotating shaft frame, enabling the rotating shaft frame to achieve stepless adjustment within a certain degree range, adapting to different hole-expanding diameter requirements, and solving the problem of poor adaptability of fixed-angle hole expanders. The angle-adjusting connecting rod, the hole-expanding vane, and the rotating shaft frame are all arranged in a ring array of three, which facilitates the three rotating shaft frames to improve the hole-expanding efficiency through the cutting blade and wear-resistant alloy teeth.

[0044] 3. A centering and guiding mechanism consisting of a centering oil pump, a second hydraulic oil pipe, a second hydraulic oil cylinder, a first pressure sensor, and a guide wheel is used. After the centering oil pump is energized, it controls the extension and retraction of the second hydraulic oil cylinder. After the second hydraulic oil cylinder extends, the guide wheel contacts the inner surface of the precast pipe pile, so that the seven second hydraulic oil cylinders work together to center the drill rod. The first pressure sensor is used to detect the pressure on the extension and retraction end of the second hydraulic oil cylinder, thereby realizing feedback adjustment. At the same time, when the sinking and expanding mechanism moves with the drill rod, the guide wheel moves on the inner wall of the precast pipe pile, so as to realize the purpose of the sinking and expanding mechanism guiding the drill rod.

[0045] 4. The sinking assistance mechanism consists of a sinking oil pump, a third hydraulic oil pipe, a third hydraulic cylinder, a second pressure sensor, and an alloy anti-slip pad. When the sinking oil pump is powered on, it causes the third hydraulic cylinder to extend and retract. After the third hydraulic cylinder extends, the alloy anti-slip pad contacts the inner wall of the precast pipe pile. At the same time, the second pressure sensor is used to detect the pressure on the extension end of the third hydraulic cylinder, thereby achieving feedback adjustment. After the alloy anti-slip pad squeezes the precast pipe pile, the drill rod is fixed to the inner wall of the precast pipe pile through the sinking and hole-expanding mechanism. This allows the drill rod to move the precast pipe pile through the sinking and hole-expanding mechanism, thus achieving the purpose of sinking the precast pipe pile. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of the present invention;

[0047] Figure 2 This is a schematic diagram of the drill rod, roller cone drill bit, and reaming mechanism in this invention.

[0048] Figure 3 This is a schematic diagram of the support ring, the first bearing, and the centering and guiding mechanism in this invention;

[0049] Figure 4 This is a schematic diagram of the second bearing, support plate, and sinking tube assist mechanism in this invention.

[0050] Figure 5 This is a schematic diagram of the sinking and expanding hole mechanism in the present invention;

[0051] Figure 6 This is a schematic diagram of the filter tube and steel needle structure in this invention;

[0052] Reference numerals: 1. Actuating part; 11. Connector; 12. Motor; 13. Hydraulic cylinder; 14. Sewage pump; 2. Power drill rod; 3. Extension drill rod; 4. Drill bit rod; 5. Roller cone drill bit; 6. Auxiliary reaming mechanism; 61. Support ring; 62. First bearing; 63. Second bearing; 64. Support plate; 65. Reaming mechanism; 651. Vane angle adjustment oil pump; 652. First hydraulic oil pipe; 653. First hydraulic oil cylinder; 654. Angle adjustment connecting rod; 655. Reaming vane; 656. Rotary shaft frame; 657. Cutting blade; 6 58. Wear-resistant alloy teeth; 659. Tilt sensor; 6510. Limit baffle; 66. Centering guide mechanism; 661. Centering oil pump; 662. Second hydraulic oil pipe; 663. Second hydraulic oil cylinder; 664. First pressure sensor; 665. Guide wheel; 67. Pipe sinking assist mechanism; 671. Pipe sinking oil pump; 672. Third hydraulic oil pipe; 673. Third hydraulic oil cylinder; 674. Second pressure sensor; 675. Alloy anti-slip pad; 7. Controller; 8. Precast pipe pile; 9. Filter pipe; 10. Steel needle. Detailed Implementation

[0053] The technical solutions in the embodiments of the present invention are described below.

[0054] Please see Figure 1-6 The present invention provides a technical solution: an integrated construction device for sinking and expanding the bottom of precast pipe piles in hard strata, comprising an action unit 1, a power drill rod 2 installed in the power unit of the action unit 1, a plurality of extension drill rods 3 screwed onto the lower end of the power drill rod 2, a drill bit rod 4 screwed onto the lower end of the extension drill rods 3, a roller cone drill bit 5 fixed at the lower end of the drill bit rod 4, a precast pipe pile 8 set outside the drill bit rod 4, and the precast pipe pile 8 being driven into the soil layer, a sinking and expanding hole mechanism 6 installed on the outer surface of the drill bit rod 4 near the roller cone drill bit 5, and a controller 7 electrically connected to the action unit 1 and the sinking and expanding hole mechanism 6;

[0055] The sinking and reaming mechanism 6 includes a support ring 61 that is sleeved on the drill rod 4. A first bearing 62 is installed inside the support ring 61, and the inner ring of the first bearing 62 is fixed outside the drill rod 4. A second bearing 63 is provided directly below the support ring 61. A support plate 64 is welded to the inner ring of the second bearing 63. The sinking and reaming mechanism 6 also includes a reaming mechanism 65 for expanding the bottom of the precast pipe pile 8, a centering and guiding mechanism 66 for guiding and centering, and a sinking tube assisting mechanism 67 for sinking.

[0056] The hole-reaming mechanism 65 is installed on the support ring 61, the second bearing 63, the support plate 64 and the drill rod 4; the centering and guiding mechanism 66 is installed on the support ring 61, and the tube sinking assist mechanism 67 is installed on the second bearing 63.

[0057] In this embodiment, a sinking and reaming mechanism 6 is constructed, consisting of a support ring 61, a first bearing 62, a second bearing 63, a support plate 64, a reaming mechanism 65, a centering and guiding mechanism 66, and a sinking tube assist mechanism 67. The support ring 61 is rotatably mounted on the outside of the drill rod 4 via the first bearing 62. The reaming mechanism 65 mounted on the support ring 61, the second bearing 63, the support plate 64, and the drill rod 4 connects the second bearing 63 to the support ring 61. The reaming mechanism 65 is used for bottom reaming. The sinking tube assist mechanism 67 mounted on the second bearing 63 is used for sinking assistance. The centering and guiding mechanism 66 mounted on the support ring 61 is used for guiding and centering the drill rod 4. The sinking assistance, bottom reaming, and drill rod 4 guidance and centering functions are integrated into the same device, reducing processes and improving efficiency.

[0058] Specifically, the reaming mechanism 65 includes a blade angle adjustment oil pump 651 fixedly mounted on the upper surface of the support ring 61, a first hydraulic cylinder 653 for adjusting the axial distance installed between the support ring 61 and the support plate 64, a first hydraulic oil pipe 652 installed between the blade angle adjustment oil pump 651 and the first hydraulic cylinder 653, a reaming blade 655 welded to the outer surface of the drill rod 4 at the lower part of the support plate 64, a rotating shaft frame 656 rotatably mounted inside the reaming blade 655, an angle adjustment connecting rod 654 rotatably mounted at one end of the rotating shaft frame 656 near the reaming blade 655, an upper end of the angle adjustment connecting rod 654 rotatably mounted on the outer ring surface of the second bearing 63, and a lower end of the angle adjustment connecting rod 654 axially connected to the swing arm fixed on the rotating shaft frame 656;

[0059] The cylinder body of the first hydraulic cylinder 653 is fixed to the lower surface of the support ring 61, and the telescopic end is fixed to the upper surface of the second bearing 63. When the first hydraulic cylinder 653 extends, it pushes the second bearing 63 to rise along the drill rod 4 axis, and pulls the rotating shaft frame 656 to rotate around the hinge point between it and the reaming blade 655 through the angle adjustment link 654, thereby realizing the unfolding of the reaming blade 655.

[0060] A limiting baffle 6510 for limiting the rotation of the shaft bracket 656 by 45 degrees is welded to the upper part of the enlarged wing 655. An angle sensor 659 for detecting the angle is installed on the inner surface of the shaft bracket 656. The wing angle adjustment oil pump 651 and the angle sensor 659 are both electrically connected to the controller 7. The angle adjustment link 654, the enlarged wing 655 and the shaft bracket 656 are arranged in a ring array of three. The free end of the shaft bracket 656 is arc-shaped and is provided with a cutting blade 657. Wear-resistant alloy teeth 658 are inlaid on the surface of the free end of the shaft bracket 656.

[0061] In this embodiment, a hole-expanding mechanism 65 is used, consisting of a vane angle-adjusting oil pump 651, a first hydraulic oil pipe 652, a first hydraulic cylinder 653, an angle-adjusting connecting rod 654, a hole-expanding vane 655, a rotating shaft bracket 656, an tilt sensor 659, and a limiting baffle 6510. When the vane angle-adjusting oil pump 651 is energized, it drives the first hydraulic cylinder 653 to extend and retract, causing the extension and retraction end of the first hydraulic cylinder 653 to lift and lower the second bearing 63. When the second bearing 63 rises, the angle is adjusted... The connecting rod 654 drives the rotating shaft bracket 656 to rotate upwards, while the limiting baffle 6510 is used to limit the rotation of the rotating shaft bracket 656, so that the rotating shaft bracket 656 can be steplessly adjusted within the range of 0-45 degrees to adapt to different bottom diameter requirements. This solves the problem of poor adaptability of fixed angle hole expanders. The angle adjusting connecting rod 654, the hole expanding wing 655 and the rotating shaft bracket 656 are all arranged in a ring array of three, which makes it easier for the three rotating shaft brackets 656 to improve the bottom expansion efficiency through the cutting blade 657 and the wear-resistant alloy teeth 658.

[0062] Specifically, the centering and guiding mechanism 66 includes a centering oil pump 661 mounted on the upper surface of a support ring 61, a second hydraulic cylinder 663 welded into a hole on the outer side of the support ring 61, a second hydraulic oil pipe 662 installed between the centering oil pump 661 and the second hydraulic cylinder 663, a first pressure sensor 664 for detecting pressure fixed at the telescopic end of the second hydraulic cylinder 663, a guide wheel 665 mounted at the end of the first pressure sensor 664, and seven second hydraulic cylinders 663 arranged in a ring array. Both the centering oil pump 661 and the first pressure sensor 664 are electrically connected to the controller 7.

[0063] In this embodiment, a centering and guiding mechanism 66 is used, consisting of a centering oil pump 661, a second hydraulic oil pipe 662, a second hydraulic oil cylinder 663, a first pressure sensor 664, and a guide wheel 665. When the centering oil pump 661 is energized, it controls the extension and retraction of the second hydraulic oil cylinder 663. After the second hydraulic oil cylinder 663 extends, the guide wheel 665 contacts the inner surface of the precast pipe pile 8, so that the seven second hydraulic oil cylinders 663 cooperate to center the drill rod 4. The first pressure sensor 664 is used to detect the pressure on the extension and retraction end of the second hydraulic oil cylinder 663, thereby realizing feedback adjustment. At the same time, when the sinking and expanding mechanism 6 moves with the drill rod 4, the guide wheel 665 moves on the inner wall of the precast pipe pile 8, so as to achieve the purpose of guiding the drill rod 4 by the sinking and expanding mechanism 6.

[0064] Specifically, the immersed tube assist mechanism 67 includes an immersed tube oil pump 671 mounted on the upper surface of the inner ring of the second bearing 63, a third hydraulic cylinder 673 welded to the upper surface of the inner ring of the second bearing 63, a third hydraulic oil pipe 672 installed between the immersed tube oil pump 671 and the third hydraulic cylinder 673, a second pressure sensor 674 for detecting pressure fixed at the telescopic end of the third hydraulic cylinder 673, an alloy anti-slip pad 675 installed at the end of the second pressure sensor 674, and nine alloy anti-slip pads 675 arranged in a ring array. The immersed tube oil pump 671 and the second pressure sensor 674 are both electrically connected to the controller 7.

[0065] In this embodiment, a sinking assistance mechanism 67, consisting of a sinking oil pump 671, a third hydraulic oil pipe 672, a third hydraulic oil cylinder 673, a second pressure sensor 674, and an alloy anti-slip pad 675, is used. When the sinking oil pump 671 is energized, it causes the third hydraulic oil cylinder 673 to extend and retract. After the third hydraulic oil cylinder 673 extends, the alloy anti-slip pad 675 contacts the inner wall of the precast pipe pile 8. At the same time, the second pressure sensor 674 is used to detect the pressure on the extension end of the third hydraulic oil cylinder 673, thereby achieving feedback adjustment. After the alloy anti-slip pad 675 squeezes the precast pipe pile 8, the drill rod 4 is fixed to the inner wall of the precast pipe pile 8 through the sinking and hole-expanding mechanism 6. This allows the drill rod 4 to move with the precast pipe pile 8 through the sinking and hole-expanding mechanism 6, thus achieving the purpose of sinking the precast pipe pile 8.

[0066] Specifically, the actuation unit 1 includes a connector 11 rotatably mounted on the upper end of the power drill rod 2. A motor 12 is fixed to the upper end of the connector 11, and the output shaft of the motor 12 is fixed to the upper end of the power drill rod 2. A hydraulic cylinder 13 is mounted on the upper end of the motor 12. A sewage pump 14 is mounted on the side of the connector 11, and the inlet end of the sewage pump 14 is connected to the power drill rod 2. The motor 12, the hydraulic cylinder 13, and the sewage pump 14 are all electrically connected to the controller 7.

[0067] Specifically, the upper end of the precast pipe pile 8 is fitted with a filter pipe 9 for liquid reflux, and the lower end of the filter pipe 9 is welded with a steel needle 10. The filter pipe 9 has a hyperbolic tubular structure and the pore size of the filter pipe 9 is 0.1 mesh.

[0068] Specifically, controller 7 includes a main control module, a data acquisition module, a hydraulic control module, a motor drive module, a signal feedback module, an alarm protection module, and a human-machine interaction module;

[0069] The data acquisition module is electrically connected to the tilt sensor 659, the first pressure sensor 664, and the second pressure sensor 674 respectively, and is used to collect construction condition data such as hole expansion angle, centering and tightening pressure, and tube extrusion pressure in real time, and transmit the collected data to the main control module.

[0070] The hydraulic control module is electrically connected to the vane angle adjustment oil pump 651, the centering oil pump 661, and the sinking pipe oil pump 671 respectively. It is used to receive instructions from the main control module and precisely control the start and stop of each oil pump, the oil pressure output, and the extension and retraction of the oil cylinder, so as to realize the automated operation of stepless adjustment of hole expansion angle, drill rod centering and guidance, and pipe pile sinking and locking.

[0071] The motor drive module is electrically connected to the motor 12, hydraulic cylinder 13, and sewage pump 14 of the actuation unit 1, and is used to control the drilling speed, drilling pressure and sewage operation start and stop, and adapt to the adaptive drilling mode of different strata such as soft soil, hard soil and rock strata.

[0072] The signal feedback module is used to receive real-time operating signals from various sensors, form a closed-loop control logic, and correct the action parameters of each actuator in real time based on angle deviation, pressure difference, and mechanism operating status to ensure construction accuracy.

[0073] The alarm protection module has built-in warning programs for pressure over-limit, angle deviation, mechanism jamming, and equipment overload. When the construction parameters are detected to exceed the preset threshold, the shutdown protection is automatically triggered and an audible and visual alarm is issued, realizing interlock protection for multi-mechanism operation and preventing equipment damage and defects in pile foundation construction quality.

[0074] The human-computer interaction module is used for parameter preset, real-time display of working conditions, and data storage and export of construction data. It can pre-enter construction parameters such as drilling speed, drilling pressure, hole enlargement angle, and pile driving pressure, while displaying the equipment operating status and stratum construction conditions in real time. It also supports iterative adjustment of parameters for segmented construction of ultra-long piles.

[0075] The method for constructing an integrated precast pipe pile sinking-base enlargement method in hard strata is as follows:

[0076] Step 1: Pre-treatment for pile positioning. The precast pipe pile 8 is smoothly hoisted to the construction site using hoisting equipment. The verticality of the precast pipe pile 8 is adjusted using a total station and a verticality measuring instrument, controlling the verticality deviation of the pile body to ≤0.5%. After adjustment, the precast pipe pile 8 is initially driven into the soil using pile driving equipment, with the penetration depth controlled at 0.8-1.2m, to achieve temporary fixation of the pile body and prevent pile body displacement during subsequent construction. At the same time, a hyperbolic filter pipe 9 is sleeved on the upper end of the precast pipe pile 8, and the filter pipe 9 is fixed by steel needles 10 at the bottom. The 0.1 mesh pores are used to filter and return construction slurry and sewage, preventing soil impurities from entering the inner cavity of the pile.

[0077] Step 2: The integrated device is positioned and fixed. The assembled sinking-expansion integrated construction device is placed into the inner cavity of the precast pipe pile 8. The centering and guiding mechanism 66 is activated by the controller 7. The centering oil pump 661 drives the second hydraulic cylinder 663 to extend, which drives the end guide wheel 665 to fit against the inner wall of the precast pipe pile 8. The seven second hydraulic cylinders 663 arranged in a ring array synchronously and adaptively tighten. The first pressure sensor 664 monitors the tightening pressure in real time and adjusts the extension and retraction of the cylinders accordingly. This achieves the overall centering and guiding of the drill rod 4, locks the construction posture of the device, and prevents the drill rod from eccentrically shaking during drilling and hole expansion.

[0078] Step 3: Adaptive pilot hole drilling. The actuator 1 is activated by the controller 7, which drives the motor 12 to rotate the power drill rod 2, the extension drill rod 3, and the roller cone drill bit 5 at the bottom of the drill bit rod 4. At the same time, the hydraulic cylinder 13 outputs constant drilling pressure. The construction parameters are adaptively adjusted according to the geological conditions: low drilling pressure and high speed mode is used for soft soil layers, high drilling pressure and low speed mode is used for hard soil layers, and the impact-rotation composite drilling mode is switched for rock strata. Pilot hole construction is continuously carried out in the stratum below the pile end of the precast pipe pile 8. The over-drilling depth of 0.3-0.5m is reserved in combination with the designed drilling depth of the pile end to ensure that the bearing layer of the pile end is fully drilled. During the drilling process, the sewage pump 14 is started to discharge the slag and mud in the hole through the hollow structure of the power drill rod 2, the extension drill rod 3, and the drill bit rod 4 to ensure the cleanliness of the hole.

[0079] Step 4: Stepless Adjustable Enlargement of the Pile End. After the pilot hole reaches the preset depth, keep the drill rod stationary in the center. Start the enlargement mechanism 65 through the controller 7. The vane angle adjustment oil pump 651 drives the first hydraulic cylinder 653 to extend through the first hydraulic oil pipe 652, which drives the second bearing 63 to rise vertically. With the help of the angle adjustment linkage 654, the shaft frame 656 and the enlargement vane 655 are driven to slowly unfold outward. The stepless angle adjustment from 0 to 45 degrees is achieved by relying on the limit baffle 6510. At the same time, the tilt sensor 659 collects the rotation angle data of the shaft frame 656 in real time and feeds it back to the controller 7 to accurately control the enlargement opening. The enlargement diameter is strictly controlled to be 1.2-1.5 times the outer diameter of the precast pipe pile 8. The three sets of enlargement vanes 655 arranged in a ring array, as well as the end cutting blades 657 and wear-resistant alloy teeth 658, cut and enlarge the soil and rock layers at the pile end to form a regular pile end enlarged head structure, thereby improving the bearing capacity of the pipe pile end.

[0080] Step 5: The hole-expanding mechanism 65 is reset and retracted. After the pile end expansion construction is completed, the controller 7 controls the vane angle adjustment oil pump 651 in reverse to drive the first hydraulic cylinder 653 to reset. This drives the angle adjustment connecting rod 654 to pull the rotating shaft frame 656 and the hole-expanding vane 655 inward to retract completely to the preset position outside the drill rod 4. This eliminates the scratching effect of the hole-expanding structure on the external soil and ensures that the drill rod can be lifted smoothly. At the same time, the tilt sensor 659 feeds back the reset signal to avoid residual opening angle of the vane causing equipment wear and pile wall damage.

[0081] Step Six: Hydraulic-assisted pile driving construction. After the hole-expanding mechanism 65 is fully reset, the pipe-driving assist mechanism 67 is activated. The pipe-driving oil pump 671 drives the third hydraulic cylinder 673 to extend, causing the end alloy anti-slip pad 675 to tightly press against the inner wall of the precast pipe pile 8. The second pressure sensor 674 monitors the pressing force in real time and provides feedback for adjustment, ensuring that the nine sets of annular array alloy anti-slip pads 675 are evenly stressed, thus achieving a stable lock between the hole-expanding mechanism 6 and the precast pipe pile 8. Subsequently, relying on the drilling rod's lowering power, the precast pipe pile 8 is driven down as a whole. With the help of the pile driving equipment, a second driving is carried out to accurately drive the precast pipe pile 8 into the design elevation, so that the pile end is completely embedded in the pile end enlarged head area, solving the problems of difficult and incomplete pile driving in hard strata.

[0082] Step 7: Pile end gap reinforcement treatment. After the pile driving construction is completed, according to the soil quality and bearing capacity design requirements, selective post-grouting construction is carried out at the pile end. Cement grout is injected into the gap between the pile end enlarged head and the bottom of the pile body through the reserved grouting channel in the pile to fill the gap in the hole, solidify the loose soil layer, strengthen the integrity of the bearing layer at the pile end, and significantly improve the vertical compressive and tensile bearing capacity of the precast pipe pile 8. After the grouting is completed, static curing is carried out to ensure that the grout solidifies and forms.

[0083] Step 8: Long pile segmented cyclic construction. For the construction of ultra-long precast pipe piles 8, if the single pile driving depth cannot reach the design elevation, repeat steps 2 to 6, and complete the secondary centering and guidance, deep drilling and bottom expansion to assist the sinking in sequence. The pipe piles are driven down segment by segment until the pile body reaches the design construction elevation. The construction status is monitored in real time by sensors throughout the process to ensure that the verticality of segmented construction and the pile driving accuracy meet the standards.

[0084] Step Nine: The entire device is recycled and reused. After all construction procedures are completed, each hydraulic mechanism is shut down in sequence, the centering and guiding mechanism 66 and the sinking tube assist mechanism 67 are reset, so that the guide wheel 665 and the alloy anti-slip pad 675 are detached from the inner wall of the pipe pile, and all the actuators are completely retracted and reset; the overall length of the central drill rod is reduced to decrease the overall volume of the device, and the integrated device is steadily lifted out of the inner cavity of the precast pipe pile 8 by hoisting equipment. Then, the vulnerable parts such as the roller cone drill bit 5, wear-resistant alloy teeth 658, hydraulic cylinders, and sensors are inspected, cleaned, maintained and replaced. After being debugged and qualified, it can be reused for subsequent pile foundation construction.

[0085] Specifically, this also includes precise control of construction parameters, equipment linkage regulation, and detailed rules for adapting to different operating conditions, as follows:

[0086] The multi-mechanism linkage electrical control details show that the entire device is centrally linked and controlled by controller 7 to achieve coordinated operation and interlocking protection of each mechanism: when the hole-expanding mechanism 65 is operating, the centering and guiding mechanism 66 maintains a stable pressure and centering state, locks the drill rod offset degree of freedom, and prohibits the sinking tube assist mechanism 67 from operating; when the pile sinking assist operation is performed, the hole-expanding blades 655 remain fully retracted and locked to avoid scraping the pile wall soil; each pressure sensor and tilt sensor 659 collects working condition data in real time to form a closed-loop feedback control. When pressure exceeds the standard, angle deviation, or mechanism jamming is detected, controller 7 automatically stops the machine and alarms to prevent equipment damage and construction quality problems.

[0087] Adaptive drilling parameter control for formations relies on real-time monitoring of formation hardness and drilling resistance data during construction. Controller 7 automatically matches the optimal construction parameters to precisely adapt to different formations: In soft soil conditions, it adopts low drilling pressure of 0.2-0.5MPa and high drilling speed of 80-120r / min to improve drilling efficiency; in hard soil conditions, it adopts high drilling pressure of 0.8-1.2MPa and low drilling speed of 30-60r / min to avoid drill bit slippage and wear; in rock formation conditions, it switches to an impact-rotation composite working mode, using high-frequency impact combined with low-speed rotation to break the rock formation, adapting to the requirements of borehole enlargement in hard formations.

[0088] The detailed rules for precision control during the enlargement construction include: throughout the enlargement operation, the rotation angle of the shaft frame 656 is monitored in real time by the tilt sensor 659, with the angle adjustment accuracy controlled within ±0.5 degrees and the enlargement diameter error controlled within ±20mm; the three sets of enlargement blades 655 are synchronously and symmetrically deployed to ensure that the pile end enlargement head has a regular circular structure, eliminating problems such as eccentric enlargement and insufficient local enlargement; the limiting baffle 6510 strictly limits the maximum rotation angle of the shaft frame 656 to 45 degrees to avoid excessive enlargement causing soil collapse and instability of the pile end structure;

[0089] According to the detailed rules for pressure control in the sinking assistance mechanism 67, when the sinking assistance mechanism 67 is working, the second pressure sensor 674 monitors the hydraulic cylinder extrusion pressure in real time and controls the extrusion pressure stably at 1.0-1.5MPa to ensure that the alloy anti-slip pad 675 is firmly attached to the pile wall and will not squeeze or damage the inner wall of the precast pipe pile 8; the pressure difference of the seven sets of centering guide hydraulic cylinders is controlled within ±0.1MPa to ensure that the drill rod is always on the central axis of the pile body, and to ensure the verticality of the pile sinking and the uniformity of the force.

[0090] The detailed rules for equipment recycling, maintenance, and reuse stipulate that all movable structures are reset without residue after construction, and the 655 reamer, 665 guide wheel, and anti-slip pad are completely housed and fitted to the main body of the mechanism without any protruding structures. During disassembly and inspection of the device, the wear of the roller cone drill bit 5 and the wear-resistant alloy tooth 658 is the focus of inspection, and any parts with excessive wear are replaced immediately. Hydraulic pipelines and bearing structures are regularly lubricated, and sensors are regularly calibrated to ensure the stability and accuracy of the equipment for repeated use and reduce the cost of construction equipment.

[0091] The mud filtration and environmental protection construction details stipulate that the mud and sewage generated during construction are filtered back through the filter pipe 9 at the top of the precast pipe pile 8. The 0.1 mesh high-precision pores can intercept solid impurities such as slag and gravel. The filtered clean water can be recycled. Impurities are collected and treated in a centralized manner to avoid construction slag from polluting the construction site and to prevent impurities from entering the pile hole and affecting the quality of pile foundation construction.

[0092] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An integrated construction device for sinking and enlarging precast pipe piles in hard strata, characterized in that: The device includes an action unit (1), a power drill rod (2) is installed in the power unit (1), a plurality of extension drill rods (3) are screwed into the lower end of the power drill rod (2), a drill bit rod (4) is screwed into the lower end of the extension drill rod (3), a roller cone drill bit (5) is fixed to the lower end of the drill bit rod (4), a precast pipe pile (8) is provided outside the drill bit rod (4), and the precast pipe pile (8) is driven into the soil layer. The device is characterized in that: a sinking and hole-expanding mechanism (6) is installed on the outer surface of the drill bit rod (4) near the roller cone drill bit (5), and a controller (7) is electrically connected to the action unit (1) and the sinking and hole-expanding mechanism (6). The sinking and expanding mechanism (6) includes a support ring (61) that is sleeved on the drill rod (4). A first bearing (62) is installed inside the support ring (61), and the inner ring of the first bearing (62) is fixed outside the drill rod (4). A second bearing (63) is provided directly below the support ring (61). A support plate (64) is welded to the inner ring of the second bearing (63). The support plate (64) abuts against the outer wall of the drill rod (4). The sinking and expanding mechanism (6) includes a hole expanding mechanism (65) for expanding the bottom of the precast pipe pile (8), a centering and guiding mechanism (66) for guiding and centering, and a sinking tube assisting mechanism (67) for sinking. The hole expanding mechanism (65) is installed on the support ring (61), the second bearing (63), the support plate (64), and the drill rod (4). The sinking tube assisting mechanism (67) is installed on the second bearing (63). The centering and guiding mechanism (66) is installed on the support ring (61).

2. The precast pipe pile hard stratum sinking-base expansion integrated construction device according to claim 1, characterized in that: The hole-expanding mechanism (65) includes a blade angle-adjusting oil pump (651) fixedly installed on the upper surface of the support ring (61), a first hydraulic cylinder (653) for adjusting the axial distance is installed between the support ring (61) and the support plate (64), a first hydraulic oil pipe (652) is installed between the blade angle-adjusting oil pump (651) and the first hydraulic cylinder (653), a hole-expanding blade (655) is welded on the outer surface of the drill rod (4) at the lower part of the support plate (64), the hole-expanding blade (655) is rotatably installed with the rotating shaft frame (656), the upper end of the angle-adjusting connecting rod (654) is rotatably installed on the outer ring surface of the second bearing (63), and the lower end of the angle-adjusting connecting rod (654) is axially connected to the swing arm fixed on the rotating shaft frame (656). The cylinder body of the first hydraulic cylinder (653) is fixed to the lower surface of the support ring (61), and the telescopic end is fixed to the upper surface of the second bearing (63). When the first hydraulic cylinder (653) extends, it pushes the second bearing (63) to rise along the drill rod (4) axially. The angle adjustment link (654) pulls the rotating shaft frame (656) to rotate around the hinge point between it and the reaming blade (655), thereby realizing the unfolding of the reaming blade (655). The upper part of the enlarged wing (655) is welded with a limiting baffle (6510) for limiting the rotation of the shaft frame (656) by 45 degrees. The inner surface of the shaft frame (656) is equipped with an angle sensor (659) for detecting the angle. Both the wing angle adjustment oil pump (651) and the angle sensor (659) are electrically connected to the controller (7).

3. The integrated construction device for sinking and enlarging precast pipe piles in hard strata according to claim 2, characterized in that: The angle adjustment link (654), the hole expansion wing (655) and the rotating shaft frame (656) are all arranged in a ring of three. The free end of the rotating shaft frame (656) is arc-shaped and is provided with a cutting blade (657) at the free end. The surface of the free end of the rotating shaft frame (656) is inlaid with wear-resistant alloy teeth (658).

4. The integrated construction device for sinking and enlarging precast pipe piles in hard strata according to claim 1, characterized in that: The centering guide mechanism (66) includes a centering oil pump (661) mounted on the upper surface of a support ring (61). A second hydraulic cylinder (663) is welded into a hole on the outer side of the support ring (61). A second hydraulic oil pipe (662) is installed between the centering oil pump (661) and the second hydraulic cylinder (663). A first pressure sensor (664) for detecting pressure is fixed at the telescopic end of the second hydraulic cylinder (663). A guide wheel (665) is installed at the end of the first pressure sensor (664). There are seven second hydraulic cylinders (663) in a ring array. The centering oil pump (661) and the first pressure sensor (664) are both electrically connected to the controller (7).

5. The integrated construction device for sinking and enlarging precast pipe piles in hard strata according to claim 1, characterized in that: The immersed tube assist mechanism (67) includes an immersed tube oil pump (671) mounted on the upper surface of the inner ring of the second bearing (63), a third hydraulic cylinder (673) welded to the upper surface of the inner ring of the second bearing (63), a third hydraulic oil pipe (672) installed between the immersed tube oil pump (671) and the third hydraulic cylinder (673), a second pressure sensor (674) for detecting pressure is fixed at the telescopic end of the third hydraulic cylinder (673), an alloy anti-slip pad (675) is installed at the end of the second pressure sensor (674), and there are nine alloy anti-slip pads (675) in a ring array. The immersed tube oil pump (671) and the second pressure sensor (674) are both electrically connected to the controller (7).

6. The integrated construction device for sinking and enlarging precast pipe piles in hard strata according to claim 1, characterized in that: The actuating unit (1) includes a connector (11) rotatably mounted on the upper end of the power drill rod (2). A motor (12) is fixed on the upper end of the connector (11), and the output shaft of the motor (12) is fixed to the upper end of the power drill rod (2). A hydraulic cylinder (13) is mounted on the upper end of the motor (12). A sewage pump (14) is mounted on the side of the connector (11), and the inlet end of the sewage pump (14) is connected to the power drill rod (2). The motor (12), the hydraulic cylinder (13) and the sewage pump (14) are all electrically connected to the controller (7).

7. The integrated construction device for sinking and enlarging precast pipe piles in hard strata according to claim 1, characterized in that: The upper end of the precast pipe pile (8) is fitted with a filter pipe (9) for liquid reflux, and the lower end of the filter pipe (9) is welded with a steel needle (10). The filter pipe (9) is a hyperbolic tubular structure, and the pore size of the filter pipe (9) is 0.1 mesh.

8. The integrated construction device for sinking and enlarging precast pipe piles in hard strata according to claim 1, characterized in that: The controller (7) includes a main control module, a data acquisition module, a hydraulic control module, a motor drive module, a signal feedback module, an alarm protection module, and a human-machine interaction module; The data acquisition module is electrically connected to the tilt sensor (659), the first pressure sensor (664), and the second pressure sensor (674) respectively, and is used to collect construction condition data such as hole expansion angle, centering and tightening pressure, and tube extrusion pressure in real time, and transmit the collected data to the main control module. The hydraulic control module is electrically connected to the vane angle adjustment oil pump (651), the centering oil pump (661), and the sinking pipe oil pump (671) respectively. It is used to receive instructions from the main control module, accurately control the start and stop of each oil pump, the oil pressure output and the extension and retraction of the oil cylinder, and realize the automated operation of stepless adjustment of hole expansion angle, drill rod centering and guidance, and pipe pile sinking and locking. The motor drive module is electrically connected to the motor (12), hydraulic cylinder (13), and sewage pump (14) of the action unit (1), and is used to control the drilling speed, drilling pressure and sewage operation start and stop, and adapt to the adaptive drilling mode of different strata such as soft soil, hard soil and rock strata. The signal feedback module is used to receive real-time operating signals from each sensor, form a closed-loop control logic, and correct the action parameters of each actuator in real time according to the angle deviation, pressure difference, and mechanism operating status to ensure construction accuracy. The alarm protection module has built-in warning programs for pressure over-limit, angle deviation, mechanism jamming, and equipment overload. When the construction parameters are detected to exceed the preset threshold, the shutdown protection is automatically triggered and an audible and visual alarm is issued, realizing interlock protection for multi-mechanism operation and preventing equipment damage and defects in pile foundation construction quality. The human-machine interaction module is used for parameter preset, real-time display of working conditions, and data storage and export of construction data. It can pre-enter construction parameters such as drilling speed, drilling pressure, hole enlargement angle, and pile driving pressure, and at the same time display the equipment operating status and stratum construction conditions in real time, supporting iterative adjustment of parameters for segmented construction of ultra-long piles.

9. The method of using the precast pipe pile hard stratum sinking-base enlargement integrated construction device according to any one of claims 1-8, characterized in that: The specific construction steps are as follows: Step 1: Pre-treatment for pile positioning. The precast pipe pile (8) is hoisted to the construction point by hoisting equipment. The verticality of the precast pipe pile (8) is adjusted by using a total station and verticality detector to control the verticality deviation of the pile body to ≤0.5%. After the adjustment is completed, the precast pipe pile (8) is initially driven into the soil layer by the pile driving equipment. The depth of the pile is controlled at 0.8-1.2m to achieve temporary fixation of the pile body and avoid the pile body deviation during subsequent construction. At the same time, a hyperbolic filter pipe (9) is sleeved on the upper end of the precast pipe pile (8). The filter pipe (9) is fixed by steel needles (10) at the bottom of the filter pipe (9). The 0.1 mesh pores are used to achieve the filtration and return of construction slurry and sewage, and to prevent soil impurities from entering the inner cavity of the pile. Step 2: The integrated device is positioned and fixed. The assembled sinking-expansion integrated construction device is placed into the cavity of the precast pipe pile (8). The centering and guiding mechanism (66) is started by the controller (7). The centering oil pump (661) drives the second hydraulic cylinder (663) to extend, which drives the end guide wheel (665) to fit against the inner wall of the precast pipe pile (8). The seven second hydraulic cylinders (663) arranged in a ring array synchronously and adaptively tighten. The first pressure sensor (664) monitors the tightening pressure in real time and adjusts the extension and retraction of the cylinder to achieve the centering and guiding positioning of the drill rod (4) as a whole, lock the construction posture of the device, and prevent the drill rod from eccentric shaking during drilling and hole expansion. Step 3: Adaptive pilot hole drilling in the strata. The actuator (1) is started by the controller (7), and the drive motor (12) drives the roller cone drill bit (5) at the bottom of the power drill rod (2), the extension drill rod (3) and the drill bit rod (4) to rotate. At the same time, the hydraulic cylinder (13) outputs constant drilling pressure. The construction parameters are adaptively adjusted according to the strata conditions: the low drilling pressure and high speed mode is adopted for soft soil layers, the high drilling pressure and low speed mode is adopted for hard soil layers, and the impact-rotation composite drilling mode is switched for rock strata. Pilot hole construction is continuously carried out in the strata below the pile end of the precast pipe pile (8). The over-drilling depth of 0.3-0.5m is reserved in combination with the designed drilling depth of the pile end to ensure that the bearing layer of the pile end is fully drilled. During the drilling process, the sewage pump (14) is started to discharge the slag and mud in the hole through the hollow structure of the power drill rod (2), the extension drill rod (3) and the drill bit rod (4) to ensure the cleanliness of the hole. Step 4: Stepless adjustable bottom expansion forming at the pile end. After the pilot hole reaches the preset depth, keep the drill rod stationary in the center. Start the expansion mechanism (65) through the controller (7). The vane angle adjustment oil pump (651) drives the first hydraulic cylinder (653) to extend through the first hydraulic oil pipe (652), driving the second bearing (63) vertical lifter. With the help of the angle adjustment connecting rod (654), the shaft frame (656) and the expansion vane (655) are driven to slowly expand outward. Relying on the limit baffle (6510), 0- The 45-degree stepless angle adjustment, while the tilt sensor (659) collects the rotation angle data of the shaft frame (656) in real time and feeds it back to the controller (7) to accurately control the hole opening; the hole diameter is strictly controlled to be 1.2-1.5 times the outer diameter of the precast pipe pile (8). The hole expansion blades (655) arranged in three ring arrays and the end cutting blades (657) and wear-resistant alloy teeth (658) are used to cut and expand the bottom of the soil and rock layers at the pile end to form a regular pile end enlarged head structure and improve the bearing capacity of the pipe pile end; Step 5: The hole-expanding mechanism (65) is reset and retracted. After the pile end expansion construction is completed, the wing angle adjustment oil pump (651) is controlled in reverse by the controller (7) to drive the first hydraulic cylinder (653) to reset. This drives the angle adjustment link (654) to pull the shaft frame (656) and the hole-expanding wing (655) to retract inward and completely retract to the preset position outside the drill rod (4). This eliminates the scratching effect of the hole-expanding structure on the external soil and ensures that the drill rod can be lifted smoothly. At the same time, the tilt sensor (659) feeds back the reset signal to avoid the residual opening angle of the wing causing equipment wear and pile wall damage. Step Six: Hydraulic-assisted pile driving construction. After the hole expansion mechanism (65) is fully reset, the pipe driving assist mechanism (67) is started. The third hydraulic cylinder (673) is driven by the pipe driving oil pump (671) to extend and drive the end alloy anti-slip pad (675) to tightly squeeze and adhere to the inner wall of the precast pipe pile (8). The second pressure sensor (674) monitors the squeezing force in real time and provides feedback and adjustment to ensure that the nine sets of annular array alloy anti-slip pads (675) are evenly stressed, so as to achieve a stable lock between the hole expansion mechanism (6) and the precast pipe pile (8). Then, relying on the drilling rod to lower the power, the precast pipe pile (8) is driven to sink as a whole. With the help of the pile driving equipment, a second re-driving is carried out to accurately sink the precast pipe pile (8) into the design elevation, so that the pile end is completely embedded in the pile end enlarged head area, solving the problem of difficult and incomplete pile driving in hard soil layers. Step 7: Pile end gap reinforcement treatment. After the pile driving construction is completed, according to the soil quality and bearing capacity design requirements, selectively carry out pile end grouting construction. Cement grout is injected into the gap between the pile end enlarged head and the bottom of the pile body through the reserved grouting channel in the pile to fill the gap in the hole, solidify the loose soil layer, strengthen the integrity of the pile end bearing layer, and greatly improve the vertical compressive and tensile bearing capacity of the precast pipe pile (8). After the grouting is completed, static curing is carried out to ensure that the grout solidifies and forms. Step 8: Long pile segmented cyclic construction. For the construction of ultra-long precast pipe piles (8), if the single pile driving depth cannot reach the design elevation, repeat steps 2 to 6, and complete the secondary centering guidance, deep drilling, and bottom expansion and sinking operations in sequence. Sink the pipe piles segment by segment until the pile body reaches the design construction elevation. The construction status is monitored in real time through sensors throughout the process to ensure that the verticality of segmented construction and the pile driving accuracy meet the standards. Step 9: The device is recycled and reused as a whole. After all construction procedures are completed, each hydraulic mechanism is shut down in sequence, the centering and guiding mechanism (66) and the sinking tube assist mechanism (67) are reset, so that the guide wheel (665) and alloy anti-slip pad (675) are separated from the inner wall of the pipe pile, and all the execution structures are completely retracted and reset; the overall length of the central drill rod is reduced, the overall volume of the device is reduced, and the integrated device is lifted out smoothly from the inner cavity of the precast pipe pile (8) by the hoisting equipment. Then, the vulnerable parts such as the roller cone drill bit (5), wear-resistant alloy teeth (658), hydraulic cylinder, and sensor are inspected, cleaned, maintained and replaced. After the debugging is qualified, it can be repeatedly put into subsequent pile foundation construction.

10. The method of using the precast pipe pile hard stratum sinking-base expansion integrated construction device according to claim 9, characterized in that: It also includes detailed rules for precise control of construction parameters, equipment linkage regulation, and working condition adaptation, as follows: Multi-mechanism linkage electrical control details: The entire device is centrally linked and controlled by the controller (7) to achieve coordinated operation and interlock protection of each mechanism: When the hole expansion mechanism (65) is working, the centering and guiding mechanism (66) maintains a stable pressure and centering state, locks the freedom of the drill rod offset, and prohibits the sinking tube assist mechanism (67) from operating; when the pile sinking assist operation is underway, the hole expansion wing (655) remains fully retracted and locked to avoid scraping the pile wall soil; each pressure sensor and tilt sensor (659) collects working condition data in real time to form a closed-loop feedback control. When pressure exceeds the standard, angle deviation, or mechanism jamming is detected, the controller (7) automatically stops and alarms to prevent equipment damage and construction quality problems. Adaptive drilling parameter control for formations relies on real-time monitoring of formation hardness and drilling resistance data during construction. The controller (7) automatically matches the optimal construction parameters to accurately adapt to different formations: In soft soil conditions, low drilling pressure of 0.2-0.5MPa and high rotation speed of 80-120r / min are used to improve drilling efficiency; In hard soil conditions, high drilling pressure of 0.8-1.2MPa and low rotation speed of 30-60r / min are used to avoid drill bit slippage and wear; In rock conditions, the impact-rotation composite working mode is switched, and the rock layer is broken by high-frequency impact combined with low-speed rotation to adapt to the requirements of borehole enlargement in hard formations. The detailed rules for the precision control of the bottom expansion construction are as follows: the rotation angle of the shaft frame (656) is monitored in real time by the tilt sensor (659) throughout the hole expansion operation, and the angle adjustment accuracy is controlled within ±0.5 degrees. The hole expansion diameter error is controlled within ±20mm. The three sets of hole expansion blades (655) are synchronously and symmetrically deployed to ensure that the pile end expansion head is a regular circular structure and to prevent eccentric bottom expansion and local insufficient expansion diameter. The limiting baffle (6510) strictly limits the maximum rotation angle of the shaft frame (656) to 45 degrees to avoid excessive hole expansion causing soil collapse and unstable pile end structure. According to the detailed rules for pressure control of sinking assistance mechanism (67), when the sinking assistance mechanism (67) is working, the second pressure sensor (674) monitors the hydraulic cylinder extrusion pressure in real time and controls the extrusion pressure stably at 1.0-1.5MPa to ensure that the alloy anti-slip pad (675) is firmly attached to the pile wall and will not squeeze and damage the inner wall of the precast pipe pile (8); the pressure difference of the seven sets of centering guide hydraulic cylinders is controlled within ±0.1MPa to ensure that the drill rod is always on the central axis of the pile body and to ensure the verticality of the pile sinking and the uniformity of the force. Equipment recycling and maintenance reuse details: After construction, all movable structures are reset without residue. The expansion blade (655), guide wheel (665), and anti-slip pad are completely housed and fit the main body of the mechanism without any protruding structures. When disassembling and inspecting the device, the wear degree of the roller cone drill bit (5) and wear-resistant alloy teeth (658) is the focus. If the wear exceeds the standard, they are replaced immediately. The hydraulic pipeline and bearing structure are regularly lubricated, and the sensors are regularly calibrated to ensure the stability and accuracy of the equipment for repeated use and reduce the cost of construction equipment. Mud filtration and environmental protection construction details: Mud and sewage generated during construction are filtered back through the filter pipe (9) at the top of the precast pipe pile (8). The 0.1 mesh high-precision pores can intercept solid impurities such as slag and gravel. The filtered water can be recycled. Impurities are collected and treated in a centralized manner to avoid construction slag from polluting the construction site and to prevent impurities from entering the pile hole and affecting the quality of pile foundation construction.

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