A hammering pile sinking device for breaking resistance of a target by strong pulse air flow and a method of use

Abstract

This invention discloses a hammer-driven pile driving device and its application method using a high-pulse airflow targeted resistance breaking mechanism, relating to the field of foundation construction technology. The device includes a hammer and related components, a high-pulse gas generation system, and a targeted resistance breaking device. The hammer and related components provide continuous hammering force through its cyclical motion, which is transmitted to the precast pile via a force transmission cylinder, pile head plate, and guide cap, guiding the pile body to sink vertically. The high-pulse gas generation system generates a high-pulse airflow, which is delivered to the pile tip through an exhaust pipe and a slurry pipe. The airflow direction can be controlled by a valve to help dissipate excess pore water pressure. The targeted resistance breaking device receives the hammering force and the high-pulse airflow to achieve targeted resistance breaking during pile driving. This device can effectively improve pile driving efficiency and stability and is suitable for pile driving construction under different geological conditions.

Description

Technical Field

[0001] This invention relates to the field of foundation construction technology in building engineering, specifically to a hammer-driven pile driving device and its application method that uses a strong pulsed airflow to target and break through resistance. Background Technology

[0002] In foundation construction of building engineering, pile driving with hammers is a widely used foundation construction method. Its principle is to use the impact force generated by the falling hammer to drive the pile into the ground to a predetermined depth, thereby providing a stable load-bearing foundation for the building. Traditional pile driving techniques mainly include diesel-powered hammer driving and hydraulic hammer driving.

[0003] When driving piles in complex geological conditions such as dense soil layers, the resistance at the bottom of the precast pile increases significantly, bringing many difficulties to the pile driving construction: In sand layers, the friction between sand grains is large, and the pile body needs to overcome a large resistance when sinking; in dense soil layers, the soil density is high, and the bottom of the precast pile is difficult to squeeze into the soil, resulting in low pile driving efficiency; in saturated clay, due to poor permeability, excess pore water pressure will appear at the bottom of the precast pile or at the bottom part of the precast pile during the hammering process, which will hinder the pile driving.

[0004] To address these issues, traditional methods typically involve increasing hammer energy, raising the weight of the hammer, or increasing the drop height. However, this approach has several drawbacks: firstly, excessive hammer energy may cause excessive stress on the pile, leading to pile cracking and damage, increasing construction costs and safety risks; secondly, simply increasing hammer energy can generate significant vibration and noise, severely impacting the surrounding environment, especially in urban areas and other locations with stringent environmental requirements.

[0005] A search revealed that patent CN118516977A discloses a steel pipe pile driving device and its usage method, comprising a steel pipe pile, with threaded grooves at the top and bottom ends of the steel pipe pile, and a soil-breaking mechanism at the bottom end of the steel pipe pile. The soil-breaking mechanism includes a threaded head threadedly installed at the bottom of the steel pipe pile, and further includes a circular block below the threaded head, a drill bit fixedly installed at the bottom of the circular block, a circular cavity inside the circular block, and a circular mounting plate inside the circular cavity. However, compared with this device, it has obvious disadvantages: firstly, it lacks a targeted resistance-breaking structure and cannot use airflow to assist in resistance breaking, resulting in lower pile driving efficiency in dense soil or hard rock layers; secondly, the excess pore water pressure generated by soil disturbance during pile driving is difficult to discharge, which can easily lead to pile displacement and affect pile driving stability.

[0006] A search revealed that patent number CN117127609A discloses a pile driving aid device and construction method for precast pipe piles. The device includes a driving aid component, which comprises a connecting component, a drill rod assembly, a drive box assembly, a reamer assembly, and a main drill bit. One end of the connecting component 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, which is sleeved on the drill rod assembly, is used to drive 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 hole. The drill rod assembly is connected to the main drill bit. The main drill bit is used to drill into the stratum covered by the projection surface of the precast pipe pile's inner cavity, and the reamer assembly is used to drill into the stratum outside the projection surface of the precast pipe pile's inner cavity. Thus, the main drill bit and the reamer bit can drill into a hole with a larger outer diameter than the precast pipe pile. The diameter of the pilot hole in this invention is larger than the outer diameter of the pile, which greatly reduces or even eliminates the pile driving resistance in hard soil layers. However, compared with this device, it has obvious disadvantages: First, it lacks a targeted resistance-breaking design and relies solely on hammer force for pile driving. In complex geological conditions such as dense soil layers and hard rock layers, its resistance-breaking ability is insufficient, resulting in low pile driving efficiency. Second, it lacks an active dissipation mechanism for excess pore water pressure and does not have a controllable airflow guiding structure. Excess pore water pressure generated by soil disturbance during pile driving is prone to accumulate, which can easily lead to problems such as soil heave on the pile side and pile position displacement, affecting construction quality. Third, the energy transmission structure is simple, and the hammer force is prone to local concentration at the pile top, which not only results in large energy loss but may also lead to pile top damage. Furthermore, it does not form a continuous hammer driving mechanism driven by a heavy hammer cycle.

[0007] Therefore, developing a new type of hammer-driven pile driving technology that can effectively solve the problem of excessive bottom resistance of precast piles, improve construction efficiency, reduce construction costs, and be environmentally friendly has important practical significance and urgent market demand. Summary of the Invention

[0008] The purpose of this invention is to provide a high-pulse airflow targeted resistance-breaking hammer-driven pile driving device and its usage method, aiming to solve the problems of excessive bottom resistance, low pile driving efficiency, significant damage to the pile body, and large environmental impact of existing hammer-driven pile driving technology under complex geological conditions. By installing an air-jetting device at the front end of the pipe pile, the pulse airflow generated by hammering is used to dissipate the stress concentration at the bottom of the precast pile, reducing the bottom resistance of the precast pile and achieving efficient pile driving; at the same time, after the pile is driven into place, post-grouting is performed to form an enlarged head, improving the pile's bearing capacity and reducing the impact on the surrounding environment.

[0009] To solve the above problems, the technical solution of the present invention is: a hammer-driven pile driving device for targeted obstruction breaking by strong pulse airflow, characterized in that: it includes a heavy hammer system, a strong pulse gas generating system and a targeted obstruction breaking device;

[0010] The hammer system includes a hammer, an oil tank, a combustion chamber, a force transmission cylinder, a guide cap, and a pile head plate. Guide rods are provided on both sides of the hammer, and the hammer moves longitudinally along the guide rods. The combustion chamber is located at the bottom of the hammer. The oil tank is located on one side of the combustion chamber and can periodically spray diesel fuel into the combustion chamber. The force transmission cylinder is located below the combustion chamber, and the guide cap and pile head plate are both located below the force transmission cylinder.

[0011] The high-pulse gas generating system includes a transmission rod, a guide plate, a return spring, a piston beam, a piston rod, a piston, an intake pin, a piston cylinder, an exhaust pipe, an upper exhaust valve pipe, and a lower exhaust valve pipe. The transmission rod is located between the guide plate and the oil tank, passes through the oil tank, and protrudes from the top of the oil tank. The transmission rod can move up and down inside the oil tank. The guide plate is located at the bottom of the piston cylinder. The piston cylinder is sleeved outside the transmission rod. The return spring is sleeved outside the transmission rod, with its upper part pressing against the lower part of the piston beam and its lower part fixed to the upper part of the guide plate. The piston beam, piston rod, and piston are all located inside the piston cylinder. The top of the piston rod is connected to the bottom of the piston beam, and its bottom is connected to the piston. The intake pin is located inside the piston. The exhaust pipe is located at the bottom of the piston cylinder. A one-way exhaust valve is installed in the exhaust pipe. The upper exhaust valve pipe is located at the top of the one-way exhaust valve, and the lower exhaust valve pipe is located at the bottom of the one-way exhaust valve.

[0012] The targeted resistance-breaking device includes a precast pile, a grout pipe, and a pile tip. The precast pile is located at the bottom of the guide cap, and a hole is reserved inside the precast pile. The grout pipe is located inside the hole of the precast pile and penetrates the precast pile. The pile tip is located at the bottom of the precast pile.

[0013] Furthermore, guide rods are provided on both sides of the hammer, and the hammer moves longitudinally along the guide rods. The combustion chamber is located at the bottom of the hammer, the oil tank is located on one side of the combustion chamber and can periodically spray diesel into the combustion chamber, the force transmission cylinder is located below the combustion chamber, and the guide cap and the pile head plate are both located below the force transmission cylinder.

[0014] Furthermore, the lower end of the intake pin is a conical section, the middle is a thin cylindrical section, and the upper end is a coarse spherical section.

[0015] Furthermore, the piston is provided with a circular hole, the inner diameter of which is slightly larger than the outer diameter of the thin cylindrical section of the intake pin, the length of the thin cylindrical section of the intake pin is greater than the height of the circular hole, the lower part of the circular hole is a conical hole, and the conical hole matches the cross-section of the conical section at the lower end of the intake pin, and the diameter of the upper coarse spherical section of the intake pin is much larger than the diameter of the circular hole on the piston.

[0016] Furthermore, the pile tip includes a pile tip vent hole, a pile tip horizontal plate, and a pile tip vertical plate. The shape and size of the pile tip horizontal plate are exactly the same as the bottom cross section of the precast pile. The pile tip vent hole is located at the center of the pile tip horizontal plate. The pile tip vent hole can be divided into a 1 / 2 circle or a 1 / 4 circle by the pile tip vertical plate.

[0017] Furthermore, when the piston moves inside the piston cylinder, it generates a strong pulse airflow. When the upper exhaust valve is open, the strong pulse airflow is discharged into the air outside the device through the upper exhaust valve and is not transmitted downward to the pile tip. When the lower exhaust valve is open, the strong pulse airflow in the stress concentration area at the bottom of the precast pile and the pile side can be discharged.

[0018] A method for using a hammer-driven pile driving device with targeted resistance breaking by strong pulsed airflow includes the following steps:

[0019] S1. Install the pile tip at the bottom of the precast pile, install the lower end of the grout pipe at the top of the pile tip vent hole at the center of the pile tip, and install the grout pipe through the hole inside the precast pile. The upper end of the grout pipe is connected to the upper vent valve pipe. Hoist the precast pile in the middle of the guide cap so that the upper end of the precast pile is in contact with the pile head plate. Align the center of the lower end of the precast pile tip with the designed pile position and adjust the verticality of the hoisting of the precast pile to meet the design requirements.

[0020] S2 lifts the hammer, simultaneously controlling the fuel tank to spray diesel fuel into the combustion chamber. During the hammer's descent, the gas pressure in the combustion chamber increases, reaching the diesel fuel's ignition point, causing it to explode and push the hammer back up. Then, exhaust gas is discharged, diesel fuel continues to be sprayed, and the hammer falls again. This cycle achieves continuous hammer impact. During the repeated descent of the hammer, it continuously strikes the transmission rod. The transmission rod moves downward under the impact of the hammer, simultaneously driving the piston beam, piston rod, and piston to move downward together in the piston cylinder, thereby generating a strong pulse airflow. When the hammer bounces up, the transmission rod bounces upward under the elastic force of the return spring, and fresh air enters the piston cylinder, preparing for the next compression to generate a strong pulse airflow. The strong pulse airflow enters the slurry pipe through the exhaust pipe and one-way exhaust valve, and then is ejected at high speed in the form of a strong pulse from the pile tip exhaust hole.

[0021] After the S3 pile driving operation is completed, the lower exhaust valve pipe is opened. After the strong pulse airflow inside the grout pipe, the strong pulse airflow in the stress concentration area at the bottom of the precast pile, and the excess pore water pressure at the bottom of the precast pile are completely dissipated, cement grout is injected into the bottom and side of the precast pile along the grout pipe and the pile tip exhaust hole. Under pressure, the cement grout fills the cracks caused by the strong pulse airflow splitting in the stress concentration area at the bottom of the precast pile and the air gaps on the side of the precast pile, thereby increasing the bearing capacity of the precast pile.

[0022] Furthermore, in step S3, after the strong pulsed airflow and the excess pore water pressure at the bottom of the precast pile completely dissipate along the grout pipe, cement grout is injected into the bottom and sides of the precast pile under pressure along the grout pipe and the vent hole at the pile tip. Under pressure, the cement grout fills the cracks caused by the strong pulsed airflow splitting in the stress concentration area at the bottom of the precast pile and the air gaps on the sides of the precast pile, thereby increasing the bearing capacity of the precast pile.

[0023] The advantages of this invention compared to existing technologies are:

[0024] (1) The strong pulse airflow targeted resistance breaking hammer driving pile device and its usage method of the present invention can directly address the problem of excessive resistance at the bottom of precast piles in sand and dense soil layers. By breaking the soil structure through strong pulse airflow, the resistance at the bottom of precast piles can be effectively reduced, and the pile driving efficiency can be significantly improved.

[0025] (2) While using hammering energy to drive the pile, some of the hammering energy is cleverly converted into the energy of strong pulse airflow to assist in pile driving, thus realizing the rational distribution and synergistic use of energy, avoiding the waste of single energy, and improving energy utilization efficiency.

[0026] (3) Compared with the traditional hammering method, the present invention uses strong pulse airflow to assist pile driving, which reduces the direct impact of hammering, thereby reducing noise and vibration pollution.

[0027] (4) By setting up a grout pipe, the excess pore water pressure at the bottom of the precast pile can be dissipated more quickly, effectively reducing the rest period of the precast pile.

[0028] (5) Cement grout is injected into the bottom and sides of the precast pile through the grout pipe and the pile tip vent hole. Under pressure, the cement grout fills the gaps at the bottom and sides of the precast pile, thereby increasing the bearing capacity of the precast pile. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the hammer-driven pile driving device for targeted resistance breaking by strong pulsed airflow according to the present invention.

[0030] Figure 2 This is a schematic diagram of the cross-sectional structure of the force transmission cylinder of the hammer-driven pile driving device for targeted resistance breaking of strong pulse airflow according to the present invention.

[0031] Figure 3 This is a schematic diagram of the air intake process of the hammer-driven pile driving device for targeted obstruction breaking by strong pulse airflow according to the present invention.

[0032] Figure 4 This is a schematic diagram of the pile tip structure of the hammer-driven pile driving device for targeted resistance breaking of strong pulse airflow according to the present invention.

[0033] Figure 5 This is a schematic diagram of the strong pulse airflow discharge process of the hammer-driven pile driving device for targeted obstruction by strong pulse airflow according to the present invention.

[0034] Figure 6 This is a schematic diagram of the targeted resistance breaking process of the hammer-driven pile driving device with strong pulse airflow of the present invention.

[0035] Figure 7 This is a schematic diagram of the post-grouting process of the hammer-driven pile driving device with strong pulse airflow targeting and resistance breaking according to the present invention.

[0036] Figure 8 This is a schematic diagram of the precast pile structure after the completion of this invention.

[0037] As shown in the figure: 1-1, counterweight; 1-2, guide rod; 1-3, oil tank; 1-4, combustion chamber; 1-5, force transmission cylinder; 1-6, pile head plate; 1-7, guide cap;

[0038] 2-1. Drive rod; 2-2. Guide plate; 2-3. Return spring; 2-4. Piston beam; 2-5. Piston rod; 2-6. Piston; 2-6-1. Circular hole; 2-7. Intake pin; 2-7-1. Coarse spherical section; 2-7-2. Fine cylindrical section; 2-7-3. Conical section; 2-8. Piston cylinder; 2-9. Exhaust pipe; 2-10. Upper exhaust valve pipe; 2-11. One-way exhaust valve; 2-12. Lower exhaust valve pipe;

[0039] 3-1. Grouting pipe; 3-2. Precast pile; 3-3. Pile tip; 3-3-1. Pile tip vent hole; 3-3-2. Pile tip horizontal plate; 3-3-3. Pile tip vertical plate;

[0040] 4-1. Strong pulsed airflow; 4-2. Stress concentration area. Detailed Implementation

[0041] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals.

[0042] It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions shown in the attached diagram, while the terms “inside” and “outside” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0043] To make the content of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0044] like Figures 1 to 8 As shown, a hammer-driven pile driving device for targeted obstruction breaking by strong pulsed airflow is characterized by comprising a heavy hammer system, a strong pulsed gas generating system, and a targeted obstruction breaking device.

[0045] The hammer system includes a hammer 1-1, an oil tank 1-3, a combustion chamber 1-4, a force transmission cylinder 1-5, a guide cap 1-7, and a pile head plate 1-6. Guide rods 1-2 are provided on both sides of the hammer 1-1, allowing it to move longitudinally along the guide rods 1-2. The hammer 1-1 is a key component providing the hammering force, moving up and down along the two guide rods 1-2. The guide rods 1-2 guide and stabilize the movement trajectory of the hammer 1-1. The weight and drop distance of the hammer 1-1 can be adjusted according to factors such as pile type and geological conditions. The combustion chamber 1-4 is located at the bottom of the hammer 1-1. The oil tank 1-3 is on one side of the combustion chamber 1-4 and periodically sprays diesel fuel into it. The hammer 1-1 is placed directly below the combustion chamber 1-4. The oil tank 1-3 periodically sprays diesel fuel into the combustion chamber 1-4. During the descent of hammer 1-1, the gas pressure in the combustion chamber 1-4 increases, reaching the ignition point of diesel fuel, causing the diesel fuel to explode and push hammer 1-1 to bounce up. Then, fuel injection and exhaust continue, and hammer 1-1 falls down. This cycle is repeated to achieve continuous hammering. The force transmission cylinder 1-5 is located below the fuel tank 1-3. The guide cap 1-7 and the pile head plate 1-6 are both located below the force transmission cylinder 1-5, transmitting the impact force of hammer 1-1 to the pile head plate 1-6 and guide cap 1-7, and then to the precast pile 3-2, ensuring that the hammering force can effectively act on the pile body. The pile head plate 1-6 and guide cap 1-7 are in contact with the precast pile 3-2. The guide cap 1-7 guides the pile body to sink vertically, while the pile head plate 1-6 directly bears the impact force transmitted by the force transmission cylinder 1-5 and distributes it evenly on the pile body.

[0046] The high-pulse gas generating system includes a transmission rod 2-1, a guide plate 2-2, a return spring 2-3, a piston beam 2-4, a piston rod 2-5, a piston 2-6, an intake pin 2-7, a piston cylinder 2-8, an exhaust pipe 2-9, an upper exhaust valve pipe 2-10, and a lower exhaust valve pipe 2-12. The transmission rod 2-1 is located between the guide plate 2-2 and the oil tank 1-3, passing through the oil tank 1-3 and protruding from its top. The transmission rod 2-1 transmits a portion of the impact energy of the diesel hammer to the piston beam 2-4, piston rod 2-5, and piston 2-6, generating a high-pulse gas flow 4-1. The transmission rod 2-1 is connected to the piston beam 2-4. Connected together to ensure effective force transmission, the guide plate 2-2 is located at the bottom of the piston cylinder 2-8, and the return spring 2-3 is mounted on the guide plate 2-2 and connected to the transmission rod 2-1. The guide plate 2-2 is located at the lower part of the piston cylinder 2-8 and is used to limit the movement direction of the transmission rod 2-1, ensuring its vertical up-and-down movement. The return spring 2-3 is mounted on the guide plate 2-2 and connected to the transmission rod 2-1. When the transmission rod 2-1 is hammered downwards and compressed by the hammer 1-1, the return spring 2-3 is compressed simultaneously. When the hammer 1-1 bounces up, the transmission rod 2-1 bounces upwards under the elastic force of the return spring 2-3, preparing for the next strong pulse airflow 4-1. The piston cylinder 2-8 is located inside the transmission rod 2-1, and the piston beam 2-4... Piston rod 2-5 and piston 2-6 are both located inside piston cylinder 2-8. The top of piston rod 2-5 is located at the bottom of piston beam 2-4, and its bottom is connected to piston 2-6. The lower part of piston beam 2-4 is connected to piston rod 2-5, and the lower part of piston rod 2-5 is connected to piston 2-6. Together, they form a piston assembly, which is installed inside piston cylinder 2-8 and can move up and down within piston cylinder 2-8. The annular gap between piston 2-6 and the inside of piston cylinder 2-8 is small to ensure good sealing. Intake pin 2-7 is located inside piston 2-6. Exhaust pipe 2-9 is located at the bottom of piston cylinder 2-8. One-way exhaust valve 2-11 is installed in exhaust pipe 2-9. Upper exhaust valve pipe 2-10 is located at the top of one-way exhaust valve 2-11. Lower exhaust... Valve pipe 2-12 is located at the bottom of one-way exhaust valve 2-11. An intake pin 2-7 is provided on the piston. The lower end of the intake pin 2-7 is a conical section 2-7-3, the middle is a thin cylindrical section 2-7-2, and the upper end is a coarse spherical section 2-7-1. A circular hole 2-6-1 is provided in the piston 2-6. The inner diameter of the circular hole 2-6-1 is slightly larger than the outer diameter of the thin cylindrical section 2-7-2 of the intake pin 2-7. The length of the thin cylindrical section 2-7-2 of the intake pin 2-7 is greater than the height of the circular hole 2-6-1. The lower part of the circular hole 2-6-1 is conical, and the conical hole matches the cross-section of the conical section 2-7-3 at the lower end of the intake pin 2-7. The diameter of the upper coarse spherical section 2-7-1 of the intake pin 2-7 is much larger than the diameter of the circular hole 2-6-1 on the piston 2-6.During the upward movement of piston 2-6, the intake pin 2-7 falls under the influence of gravity. Air enters the piston cylinder 2-8 through the annular gap between the upper circular hole 2-6-1 of piston 2-6 and the cylindrical section of intake pin 2-7. As piston 2-6 falls, intake pin 2-7 moves upward due to inertia, and the conical section at the lower end of intake pin 2-7 moves up and down, filling the lower conical hole of upper circular hole 2-6-1 of piston 2-6. Intake pin 2-7 closes, ensuring that the interior of piston cylinder 2-8 is sealed, thereby enabling the piston to generate a strong pulse airflow 4-1.

[0047] The targeted obstacle-breaking device includes a precast pile 3-2, a grout pipe 3-1, and a pile tip 3-3. The precast pile 3-2 is located at the bottom of the guide cap 1-7. A hole is pre-drilled inside the precast pile 3-2. The grout pipe 3-1 is located inside the hole of the precast pile 3-2 and penetrates through it. The pile tip 3-3 is located at the bottom of the precast pile 3-2. The precast pile 3-2 has high strength and good durability, capable of withstanding hammer impact and lateral soil pressure, ensuring the stability of the pile body during construction. The precast pile 3-2 can have a circular or square cross-section to meet the needs of different projects. A pre-drilled hole exists in the center of the precast pile, and the grout pipe 3-1 penetrates through this pre-drilled hole. The upper end of the grout pipe 3-1... Connected to the exhaust pipe 2-9, the lower end of the grout pipe 3-1 is connected to the pile tip exhaust hole 3-3-1 in the middle of the pile tip 3-3. The pile tip 3-3 is installed at the bottom of the precast pile 3-2. The pile tip 3-3 includes the pile tip exhaust hole 3-3-1, the pile tip horizontal plate 3-3-2 and the pile tip vertical plate 3-3-3. The shape and size of the pile tip horizontal plate 3-3-2 are exactly the same as the bottom cross section of the precast pile 3-2. The pile tip vertical plate 3-3-3 is installed vertically at the lower part of the pile tip horizontal plate 3-3-2. The pile tip vertical plate 3-3-3 can be in the form of a straight line or a cross, etc. The pile tip exhaust hole 3-3-1 is located at the center of the pile tip horizontal plate 3-3-2. The pile tip exhaust hole 3-3-1 may be divided into a 1 / 2 circle or a 1 / 4 circle by the pile tip vertical plate 3-3-3.

[0048] A method for using a hammer-driven pile driving device with targeted resistance breaking by strong pulsed airflow includes the following steps:

[0049] S1. Install the pile tip 3-3 at the lower part of the precast pile 3-2. Install the lower end of the grout pipe 3-1 at the upper part of the pile tip vent hole 3-3-1 at the center of the pile tip 3-3. The grout pipe 3-1 is installed through the hole inside the precast pile 3-2. The upper end of the grout pipe 3-1 is connected to the upper vent pipe 2-10. Hoist the precast pile 3-2 in the middle of the guide cap 1-7. The upper end of the precast pile 3-2 is in contact with the pile head plate 1-6. The center of the pile tip 3-3 at the lower end of the precast pile 3-2 is aligned with the designed pile position. Adjust the verticality of the hoisting of the precast pile 3-2 to meet the design requirements.

[0050] S2 lifts the hammer 1-1 and synchronously sprays diesel fuel into the combustion chamber. During the fall of the hammer 1-1, the air pressure in the combustion chamber 1-4 increases. When the diesel fuel reaches its ignition point, it explodes, pushing the hammer 1-1 to bounce up. Then, exhaust gas is expelled and fuel continues to be injected. The hammer 1-1 falls, and so on, to achieve the continuous hammering effect of 1-1.

[0051] In step S2, during the repeated cyclical falling of the hammer 1-1, the transmission rod 2-1 is repeatedly struck. Under the impact of the hammer 1-1, the transmission rod 2-1 moves downward, simultaneously driving the piston beam 2-4, piston rod 2-5, and piston 2-6 to move downward together within the piston cylinder 2-8, thereby generating a strong pulse airflow 4-1. When the hammer 1-1 bounces up, under the elastic force of the return spring 2-3, the transmission rod 2-1 bounces up, and fresh air enters the piston cylinder 2-8 to prepare for the next compression of the strong pulse airflow 4-1. The strong pulse airflow 4-1 enters the slurry pipe 3-1 through the exhaust pipe 2-9 and the one-way exhaust valve 2-11, and then is ejected at high speed in the form of a strong pulse from the pile tip exhaust hole 3-3-1.

[0052] In loose soil layers and other strata with low bottom resistance of precast piles 3-2, pile driving is relatively easy, and fewer hammer blows are required per unit pile driving depth. There is no need for targeted resistance breaking by strong pulse airflow. The upper exhaust valve pipe 2-10 can be opened, and the strong pulse airflow 4-1 generated by the piston 2-6 moving up and down in the piston cylinder 2-8 can be directly discharged through the upper exhaust valve pipe 2-10 to the outside of the diesel pile driving hammer device and into the air. At this time, the strong pulse airflow 4-1 is not transmitted downward to the pile tip 3-3, and the hammering energy of the hammer 1-1 is completely transmitted to the bottom of the precast pile 3-2, pushing the precast pile 3-2 to sink.

[0053] In strata with high bottom resistance, such as sand, dense soil, or saturated clay, driving precast piles (3-2) is challenging. This necessitates targeted breaking of the resistance with a strong pulsed airflow. With the upper exhaust valve 2-10 and lower exhaust valve 2-12 closed, the strong pulsed airflow 4-1 is fully transmitted to the pile tip 3-3 and the pile tip exhaust port 3-3-1. As the number of hammer blows required per unit pile driving depth increases, the number of strong pulsed airflows 4-1 generated by the piston 2-6 also increases, thereby increasing the flow rate of the strong pulsed airflow ejected from the pile tip exhaust port 3-3-1, achieving dynamic coordination with the pile driving speed. The strong pulse airflow can effectively split and destroy the structure of the soil at the bottom of the precast pile 3-2, dissipate the high stress in the stress concentration area, reduce the bottom resistance of the precast pile 3-2, and form an air gap on the pile side to reduce the pile side friction. In addition, most of the hammering energy is still transferred to the pipe pile body, pushing the pipe pile to sink. During the pile driving process, the pressure in the pile tip and the exhaust pipe 2-9 should be closely monitored. When the pressure at the bottom of the precast pile 3-2 is too high, the lower exhaust valve pipe 2-12 can be opened to discharge the concentrated strong pulse airflow and excess pore water pressure at the bottom of the precast pile 3-2, which is beneficial to the pile driving.

[0054] S3 After the pile driving is completed, open the lower exhaust valve pipe 2-12 to release the strong pulse airflow 4-1 inside the grout pipe 3-1, lift the hammer 1-1 and the force transmission cylinder 1-5 upwards, so that the guide cap 1-7 and the pile head horizontal plate 3-3-2 are separated from the top of the precast pile 3-2, and disassemble the grout pipe 3-1 and the exhaust pipe 2-9.

[0055] In step S3, after the strong pulsed airflow 4-1 inside the stress concentration area 4-2 at the bottom of the precast pile 3-2 and the excess pore water pressure at the bottom of the precast pile 3-2 are completely dissipated along the grout pipe 3-1, cement grout is injected into the bottom and side of the precast pile 3-2 along the grout pipe 3-1 and the pile tip exhaust hole 3-3-1. Under pressure, the cement grout fills the cracks caused by the splitting of the strong pulsed airflow 4-1 in the stress concentration area 4-2 at the bottom of the precast pile 3-2 and the air gaps on the side of the precast pile 3-2, thereby increasing the bearing capacity of the precast pile 3-2.

[0056] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A hammer-driven pile driving device for targeted resistance breaking by strong pulsed airflow, comprising a hammer system, said hammer system comprising a hammer (1-1), an oil tank (1-3), a combustion chamber (1-4), a force transmission cylinder (1-5), a guide cap (1-7), and a pile head plate (1-6), characterized in that it further comprises... include: High-pulse gas generation system and targeted resistance-breaking device; The high-pulse gas generating system includes a transmission rod (2-1), a guide plate (2-2), a return spring (2-3), a piston beam (2-4), a piston rod (2-5), a piston (2-6), an intake pin (2-7), a piston cylinder (2-8), an exhaust pipe (2-9), an upper exhaust valve pipe (2-10), and a lower exhaust valve pipe (2-12). The transmission rod (2-1) is located between the guide plate (2-2) and the oil tank (1-3), passes through the oil tank (1-3), and protrudes from the top of the oil tank (1-3). The transmission rod (2-1) can move up and down within the oil tank (1-3). The guide plate (2-2) is located at the bottom of the piston cylinder (2-8), and the piston cylinder (2-8) is sleeved on the outside of the transmission rod (2-1). The return spring (2-3) is sleeved on the outside of the piston rod (2-1). Located outside the transmission rod (2-1), the upper part of the return spring (2-3) rests against the lower part of the piston beam (2-4), and the lower part is fixed on the upper part of the guide plate (2-2). The piston beam (2-4), piston rod (2-5), and piston (2-6) are all located inside the piston cylinder (2-8). The top of the piston rod (2-5) is connected to the bottom of the piston beam (2-4), and the bottom is connected to the piston (2-6). The intake pin (2-7) is located inside the piston (2-6). The exhaust pipe (2-9) is located at the bottom of the piston cylinder (2-8). A one-way exhaust valve (2-11) is installed in the exhaust pipe (2-9). The upper exhaust valve pipe (2-10) is located at the top of the one-way exhaust valve (2-11), and the lower exhaust valve pipe (2-12) is located at the bottom of the one-way exhaust valve (2-11). The targeted resistance-breaking device includes a precast pile (3-2), a grout pipe (3-1), and a pile tip (3-3). The precast pile (3-2) is located at the bottom of the guide cap (1-7). A hole is reserved inside the precast pile (3-2). The grout pipe (3-1) is located inside the hole of the precast pile (3-2) and penetrates the precast pile (3-2). The pile tip (3-3) is located at the bottom of the precast pile (3-2).

2. The hammer-driven pile driving device for targeted resistance breaking by strong pulsed airflow according to claim 1, characterized in that: The hammer (1-1) is provided with guide rods (1-2) on both sides. The hammer (1-1) moves longitudinally along the guide rods (1-2). The combustion chamber (1-4) is located at the bottom of the hammer (1-1). The oil tank (1-3) is located on one side of the combustion chamber (1-4) and can periodically spray diesel into the combustion chamber (1-4). The force transmission cylinder (1-5) is located below the combustion chamber (1-4). The guide cap (1-7) and the pile head plate (1-6) are both located below the force transmission cylinder (1-5).

3. The hammer-driven pile driving device for targeted resistance breaking by strong pulsed airflow according to claim 1, characterized in that: The lower end of the intake pin (2-7) is a conical section (2-7-3), the middle is a thin cylindrical section (2-7-2), and the upper end is a coarse spherical section (2-7-1).

4. The hammer-driven pile driving device for targeted resistance breaking by strong pulsed airflow according to claim 1, characterized in that: The piston (2-6) is provided with a circular hole (2-6-1). The inner diameter of the circular hole (2-6-1) is slightly larger than the outer diameter of the thin cylindrical section (2-7-2) of the intake pin (2-7). The length of the thin cylindrical section (2-7-2) of the intake pin (2-7) is greater than the height of the circular hole (2-6-1). The lower part of the circular hole (2-6-1) is a conical hole, and the conical hole matches the cross section of the conical section (2-7-3) at the lower end of the intake pin (2-7). The diameter of the upper coarse spherical section (2-7-1) of the intake pin (2-7) is much larger than the diameter of the circular hole (2-6-1) on the piston (2-6).

5. The hammer-driven pile driving device for targeted resistance breaking by strong pulsed airflow according to claim 1, characterized in that: The pile tip (3-3) includes a pile tip vent hole (3-3-1), a pile tip horizontal plate (3-3-2), and a pile tip vertical plate (3-3-3). The shape and size of the pile tip horizontal plate (3-3-2) are exactly the same as the bottom cross section of the precast pile (3-2). The pile tip vent hole (3-3-1) is located at the center of the pile tip horizontal plate (3-3-2). The pile tip vent hole (3-3-1) can be divided into a 1 / 2 circle or a 1 / 4 circle by the pile tip vertical plate (3-3-3).

6. The hammer-driven pile driving device for targeted resistance breaking by strong pulsed airflow according to claim 1, characterized in that: When the piston (2-6) moves inside the piston cylinder (2-8), it generates a strong pulse airflow (4-1). When the upper exhaust valve pipe (2-10) is open, the strong pulse airflow (4-1) is discharged into the air outside the device through the upper exhaust valve pipe (2-10) and is not transmitted downward to the pile tip (3-3). When the lower exhaust valve pipe (2-12) is open, the strong pulse airflow (4-1) at the stress concentration area (4-2) at the bottom of the precast pile (3-2) and the side of the pile can be discharged.

7. A method for using a hammer-driven pile driving device with targeted resistance breaking by strong pulsed airflow, characterized in that: Includes the following steps: S1. Install the pile tip (3-3) at the lower part of the precast pile (3-2), and install the lower end of the grout pipe (3-1) at the upper part of the pile tip vent hole (3-3-1) at the center of the pile tip (3-3). The grout pipe (3-1) is installed through the hole inside the precast pile (3-2). The upper end of the grout pipe (3-1) is connected to the upper vent valve pipe (2-10). Hoist the precast pile (3-2) in the middle of the guide cap (1-7) so that the upper end of the precast pile (3-2) is close to the pile head plate (1-6). Align the center of the pile tip (3-3) at the lower end of the precast pile (3-2) with the designed pile position, and adjust the hoisting verticality of the precast pile (3-2) to meet the design requirements. S2 lifts the hammer (1-1) and simultaneously controls the fuel tank to spray diesel fuel into the combustion chamber. During the fall of the hammer (1-1), the gas pressure in the combustion chamber (1-4) increases, reaching the ignition point of the diesel fuel, causing it to explode and push the hammer (1-1) to bounce up. Then, exhaust gas is discharged, and diesel fuel continues to be sprayed. The hammer (1-1) falls again, and this cycle is repeated to achieve continuous hammering of the hammer (1-1). During the repeated cycle of hammer (1-1) falling, it continuously strikes the transmission rod (2-1). The transmission rod (2-1) moves downward under the impact of the hammer (1-1), and at the same time drives the piston beam (2-4). The piston rod (2-5) and piston (2-6) move downward together in the piston cylinder (2-8), thereby generating a strong pulse airflow (4-1). When the counterweight (1-1) bounces up, under the elastic force of the return spring (2-3), the transmission rod (2-1) bounces up, and fresh air enters the piston cylinder (2-8) to prepare for the next compression to generate a strong pulse airflow (4-1). The strong pulse airflow (4-1) enters the slurry pipe (3-1) through the exhaust pipe (2-9) and the one-way exhaust valve (2-11), and then is ejected at high speed in the form of a strong pulse from the pile tip exhaust hole (3-3-1). After the S3 pile driving operation is completed, open the lower exhaust valve pipe (2-12). After the strong pulse airflow (4-1) inside the grout pipe (3-1), the strong pulse airflow (4-1) in the stress concentration area (4-2) at the bottom of the precast pile (3-2) and the excess pore water pressure at the bottom of the precast pile (3-2) are completely dissipated, inject cement grout into the bottom and side of the precast pile (3-2) along the grout pipe (3-1) and the pile tip exhaust hole (3-3-1). Under pressure, the cement grout fills the cracks in the stress concentration area (4-2) at the bottom of the precast pile (3-2) caused by the splitting of the strong pulse airflow (4-1) and the air gap on the side of the precast pile (3-2), thereby increasing the bearing capacity of the precast pile (3-2).

8. The method of using the hammer-driven pile driving device for targeted resistance breaking by strong pulsed airflow according to claim 7, characterized in that: In step S3, after the strong pulse airflow (4-1) and the excess pore water pressure at the bottom of the precast pile (3-2) completely dissipate along the grout pipe (3-1) in the stress concentration area (4-2) at the bottom of the precast pile (3-2), cement grout is injected into the bottom and side of the precast pile (3-2) under pressure along the grout pipe (3-1) and the pile tip exhaust hole (3-3-1). Under pressure, the cement grout fills the cracks in the stress concentration area (4-2) at the bottom of the precast pile (3-2) caused by the splitting of the strong pulse airflow (4-1) and the air gap on the side of the precast pile (3-2), thereby increasing the bearing capacity of the precast pile (3-2).

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