An air-lift reverse circulation process and drilling tool device

Abstract

The present application relates to a kind of air-lift reverse circulation processes, comprising the following steps: S1, in the process of hollow drill rod and drill bit drilling, start air compressor, compressed air is injected to the double-channel conversion mechanism being equipped on hollow drill rod by communication pipe, and air-lift reverse circulation is carried out by double-pipe assembly on hollow drill rod and mixer on hollow drill rod;S2, start grout pump, high-pressure mud is injected to the double-channel conversion mechanism being equipped on hollow drill rod by communication pipe, and high-pressure mud is injected to the annular slurry tank on drill bit by double-pipe assembly on hollow drill rod;S3, high-pressure mud is sprayed from slurry pipe from slurry nozzle from annular slurry tank, the cutter at the bottom of drill bit is cooled, and the rock debris generated by crushing is washed, so that rock debris is quickly into the mud carrying residue flow of drill pipe, and is taken out of hole by air-lift reverse circulation flow;The present application has the advantages of significantly prolonging the service life of drill bit, greatly improving drilling efficiency, reducing comprehensive construction cost, and improving hole bottom cleanliness.

Description

Technical Field

[0001] This invention belongs to the field of foundation construction technology, and particularly relates to an air lift reverse circulation process and drilling device. Background Technology

[0002] Large-diameter bored piles are a common foundation type in large bridges, high-rise buildings, and other engineering projects. A key technology during the drilling process is how to efficiently and effectively remove the broken rock cuttings (drill cuttings) from the bottom of the hole. Currently, air-lift reverse circulation technology is one of the mainstream technologies.

[0003] A typical system for this process includes a drilling rig, drill pipe, air compressor, mud pit, and circulation system. Its working principle is as follows: an air duct is installed on the side wall of the drill pipe, with its lower end connected to a device called a "mixer." Compressed air generated by the air compressor enters the mixer inside the drill pipe through the air duct, mixing with the mud inside the drill pipe to form a three-phase "gas-liquid-solid" mixture with a density much lower than the mud outside the drill pipe. Due to the significant density difference between the inside and outside of the drill pipe, the mixture inside the drill pipe flows upward at high speed under the pressure difference, acting like an "airlift pump," continuously drawing drill cuttings from the bottom of the hole to the surface through the central channel of the drill pipe. The mud carrying the drill cuttings is then purified by sedimentation and flows back into the hole, forming a circulation.

[0004] Although the air-lift reverse circulation process has high slag removal efficiency, in practical applications, especially when drilling in hard rock formations, there are two prominent technical problems: (1) Poor cooling of the drill bit bottom: When the drill bit (especially the hobbing drill bit) is breaking hard rock, the teeth of the drill bit (especially the hobbing drill bit) generate a lot of heat due to the intense friction between the teeth and the rock, which causes the temperature of the teeth to rise sharply. The excessively high temperature will accelerate the wear of the teeth and significantly shorten the service life of the drill bit. The existing process mainly relies on the slow-flowing mud at the bottom of the hole for natural cooling, which is far from sufficient.

[0005] (2) Repeated crushing of rock cuttings, resulting in low drilling efficiency: Some of the rock cuttings crushed by the cutting rollers are not carried away by the drilling mud in time and remain at the bottom of the hole. These rock cuttings will be repeatedly crushed by the cutting rollers, resulting in "repeated crushing". This not only wastes crushing energy and reduces effective drilling efficiency, but also aggravates the wear of the cutting rollers, forming a vicious cycle. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an air lift reverse circulation process and drilling tool device that integrates active flushing and cooling functions to solve the problems of insufficient drill bit cooling and repeated crushing of rock cuttings in the existing air lift reverse circulation process.

[0007] The objective of this invention is achieved through the following technical solution: this air-lift reverse circulation process includes the following steps: S1. During the drilling process of the hollow drill rod and drill bit, start the air compressor and inject compressed air into the dual-channel conversion mechanism on the hollow drill rod through the connecting pipe. The compressed air is then airlifted and reverse-circulated to remove slag through the dual-pipe assembly on the hollow drill rod and the mixer on the hollow drill rod. S2. Simultaneously start the grouting pump, inject high-pressure mud into the dual-channel conversion mechanism on the hollow drill rod through the connecting pipe, and inject high-pressure mud into the annular grout reservoir on the drill bit through the dual-pipeline assembly on the hollow drill rod. S3. High-pressure mud is ejected from the annular mud reservoir through the mud pipe and from the mud outlet nozzle, cooling the cutting teeth at the bottom of the drill bit and actively flushing the rock cuttings generated by the breakage. This allows the rock cuttings to quickly enter the mud and carry the debris into the pipe, where they are carried out of the hole by the air-lift reverse circulation.

[0008] The beneficial effects of this invention are as follows: Compared with the prior art, the forced cooling of the cutter head by high-pressure mud solves the problem of excessive wear of the cutter teeth caused by high temperature in the traditional process; the active flushing removes rock debris from the bottom of the hole in a timely manner, effectively avoiding repeated crushing and allowing all the energy of the cutter head to be used to crush the new rock surface; the active flushing helps to quickly guide the rock debris to the central slag inlet, improving the slag discharge efficiency, making the bottom of the hole cleaner, creating good conditions for subsequent hole cleaning and concrete pouring, and helping to ensure the quality of pile formation.

[0009] A drilling tool device employing the air-lift reverse circulation process described above includes a dual-pipeline assembly on the outer side of the hollow drill rod for simultaneously supplying compressed air and mud. A dual-channel conversion mechanism is connected to the dual-pipeline assembly, containing two channels for supplying compressed air or mud, respectively. Each channel is connected to a pipe within the dual-pipeline assembly. The dual-channel conversion mechanism is coaxially mounted on the upper end of the hollow drill rod and fixed to the power head. By providing the dual-channel conversion mechanism, which is coaxially mounted and rotates with the hollow drill rod, the hollow drill rod can simultaneously supply compressed air and mud. By synchronously supplying mud during drilling, the cutting teeth are cooled more effectively during high-speed rotation of the hollow drill rod, and mud pipe torsion is prevented.

[0010] Preferably, the dual-channel conversion mechanism includes a rotating body, a fixed body, and a wear-resistant sleeve. The wear-resistant sleeve is fitted onto the outer circumferential wall of the rotating body, and the fixed body is fitted onto the outer circumferential wall of the wear-resistant sleeve. The rotating body is mounted and fixed on the drive head of the power head and rotates synchronously with the hollow drill rod. The fixed body is mounted and fixed on the fixed housing of the power head. Bearings are respectively installed between the outer circumferential walls at the upper and lower ends of the rotating body and the outer circumferential walls at the upper and lower ends of the fixed body. Pressure caps are respectively installed on the axial ends of the bearings and the upper and lower ends of the fixed body. The pressure caps are fixed to the upper and lower ends of the fixed body by bolts. Two annular channels are provided between the rotating body, the wear-resistant sleeve, and the fixed body, distributed along the axial direction of the rotating body. Through the above structure, the rotating body, the fixed body, and the wear-resistant sleeve can rotate relative to each other. At the same time, the two annular channels enable the dual-channel conversion mechanism to simultaneously supply compressed air to the hollow drill rod and mud to the drill bit.

[0011] Preferably, the outer circumferential wall of the rotating body is provided with two rings of first fluid grooves, and the outer circumferential wall of the wear-resistant sleeve is provided with two rings of second fluid grooves. The first fluid grooves and the second fluid grooves are distributed in a one-to-one correspondence and are independently connected. The outer circumferential wall of the rotating body fits into the inner circumferential wall of the wear-resistant sleeve and is sealed by a sealing ring. The outer circumferential wall of the wear-resistant sleeve fits into the inner circumferential wall of the fixed body and is sealed by a sealing ring. The fixed body is equipped with four connectors for connecting to an external grouting pump or air compressor. The connectors are connected to the second fluid grooves, and each second fluid groove has two corresponding connectors that are connected. The arrangement of the first and second fluid grooves allows them to communicate with each other, and the fitting points are sealed by sealing rings. Through the distribution of the connectors, each of the two second fluid grooves can be supplied with compressed air or slurry through its respective connector. In actual use, they do not interfere with each other, resulting in more stable operation.

[0012] Preferably, the first fluid tank is divided into an upper fluid tank and a lower fluid tank. The lower wall of the upper fluid tank has two first connecting holes, and the lower wall of the lower fluid tank has two through holes and two second connecting holes. A connecting pipe is installed between the first connecting holes of the upper fluid tank and the through holes of the lower fluid tank. A connecting pipe is installed in the second connecting holes of the lower fluid tank. All connecting pipes extend beyond the axial direction of the rotating body and are connected to the pipes in the dual-pipe assembly. The second fluid tank has two rings, which are distributed in a one-to-one correspondence with the upper and lower fluid tanks. The circumferential wall of the second fluid tank... The upper part is provided with several equally spaced connecting holes, all of which are connected to the upper fluid channel and the lower fluid channel. By providing through holes and connecting holes on the upper and lower fluid channels, the compressed air or mud in the upper and lower fluid channels can be connected to the pipelines in the dual-pipe assembly through the connecting pipes, further realizing the effect of simultaneously supplying compressed air to the hollow drill rod and mud to the drill bit through the dual-channel conversion mechanism. By setting the equally spaced connecting holes, the compressed air or mud introduced through the connecting holes is more uniform when the first fluid channel of the rotating body rotates, which greatly improves the stability of the rotating body during the rotation process.

[0013] Preferably, the dual-pipeline assembly includes two pipes for compressed air and two pipes for mud. The two ends of each pipe are respectively mounted and fixed to flanges at both axial ends of the hollow drill rod, and the main body of each pipe is mounted and fixed to anti-torsion seats in the radial direction of the hollow drill rod. The mud pipe is connected to an annular slurry reservoir inside the drill bit connected to the hollow drill rod, and the compressed air pipe is connected to a mixer inside the hollow drill rod. This installation configuration improves the stability of the pipes on the sidewall of the hollow drill rod, reducing wobbling during rotation and facilitating assembly and disassembly. The separate connections of the pipes improve the cooling effect of the cutting teeth and the air-lift reverse circulation effect, allowing both to be performed simultaneously.

[0014] Preferably, the upper part of the drill bit is provided with an annular slurry reservoir, which is connected to a slurry pipe on the outside of the hollow drill rod for conveying mud. At least two downward-extending slurry pipes are evenly arranged on the outer circumferential wall of the drill bit, and these slurry pipes are connected to the annular slurry reservoir. The hollow drill rod extends to the bottom of the drill bit and is fixed therein. A mud-carrying inflow pipe is provided at the bottom circumferential wall of the hollow drill rod, and this mud-carrying inflow pipe is connected to the bottom plate of the drill bit. A slurry nozzle is fixed at the bottom end of each slurry pipe. All nozzles are oriented towards the cutting teeth of the drill bit. By setting up an annular slurry reservoir and connecting it to the pipeline, the cutting teeth at the bottom of the drill bit can be rapidly cooled, significantly improving the service life of the drill bit. At the same time, a mud-carrying inflow pipe is set on the hollow drill rod, and with the help of pipeline flushing, the rock cuttings at the bottom of the hole can be quickly guided into the hollow drill rod through the mud-carrying inflow pipe and discharged externally by air lift reverse circulation, greatly improving the cuttings discharge efficiency. The setting of the slurry nozzle is more conducive to cooling the cutting teeth at the bottom of the drill bit, and the cutting teeth can be directly cooled by mud flushing.

[0015] Preferably, the drill bit is hollow inside, and the mud-carrying inflow pipe is located inside the drill bit. One end of the mud-carrying inflow pipe communicates with the interior of the hollow drill rod, and the other end communicates with the bottom plate of the drill bit. The inlet of the mud-carrying inflow pipe is located on the side of the hollow drill rod. With the above structure, it is not only easy to install and form the mud-carrying inflow pipe, but also to maximize the utilization of the limited space, so that the rock cuttings at the bottom of the hole can be discharged through the mud-carrying inflow pipe and the hollow drill rod by air lift reverse circulation.

[0016] Preferably, the mud-carrying inflow pipe consists of a vertical pipe and an inclined pipe. The vertical pipe is connected to the inclined pipe, and the vertical pipe is perpendicular to and connected to the bottom plate of the drill bit. The inclined pipe is connected to the interior of the hollow drill rod, and the inclined pipe is distributed at an angle along the height direction of the drill bit. An inclined plate is provided inside the hollow drill rod, and the inclined plate is fixed to the inner circumferential wall of the hollow drill rod. The inclined plate is located below the wall of the inclined pipe, and the slope of the inclined plate is the same as the slope of the inclined pipe. The vertical pipe can improve the efficiency of rock cuttings suction, and the inclined pipe makes the rock cuttings enter the hollow drill rod more smoothly, greatly improving the cuttings removal efficiency. By setting the inclined plate, the rock cuttings will not fall to the bottom of the hollow drill rod and settle, and at the same time, the smoothness of the rock cuttings entering the hollow drill rod is greatly improved, thus improving the cuttings removal efficiency.

[0017] Preferably, the annular slurry reservoir is fixed to the upper end of the drill bit, and the outer diameter of the annular slurry reservoir is equal to the outer diameter of the drill bit; the outer circumferential wall of the drill bit is provided with a plurality of reinforcing ribs distributed at equal intervals, and the diameter of the reinforcing ribs is larger than the diameter of the pipeline; the above-mentioned arrangement of the annular slurry reservoir makes the annular slurry reservoir more stable during the rotation of the drill bit; by setting the reinforcing ribs, not only is the strength of the drill bit improved, but the stability of the pipeline during operation can also be protected. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the drilling device structure of the present invention.

[0019] Figure 2 This is a three-dimensional structural diagram of the drill pipe device of the present invention.

[0020] Figure 3 This is a schematic diagram of the main cross-sectional structure of the drill pipe device of the present invention.

[0021] Figure 4 This is a schematic diagram of the rotating body structure of the present invention.

[0022] Figure 5 This is a schematic diagram of the wear-resistant sleeve structure of the present invention.

[0023] Figure 6 This is a schematic diagram of the drill bit device structure of the present invention.

[0024] Figure 7 This is a schematic diagram of the main cross-sectional structure of the drill bit device of the present invention.

[0025] The labels in the attached diagram are as follows: 100, Hollow drill rod; 101, Flange; 102, Anti-torsion seat; 200, Dual-pipeline assembly; 201, Pipeline; 300, Dual-channel conversion mechanism; 301, Rotating body; 302, Fixed body; 303, Wear-resistant sleeve; 304, Bearing; 305, Gland; 306, First fluid groove; 307, Second fluid groove; 308, Sealing ring; 309, Upper fluid groove; 310, Lower fluid groove; 311, First connecting hole; 312, Through hole; 313, Second connecting hole; 314, Connecting pipe; 315, Connecting hole; 316, Joint body; 400, Drill bit; 401, Cutting teeth; 402, Reinforcing rib; 500, Annular slurry reservoir; 501, Slurry pipe; 502. Slurry outlet nozzle; 600. Slurry and slag inflow pipe; 601. Vertical pipe; 602. Inclined pipe; 603. Inclined plate. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings: As shown in the drawings, the air lift reverse circulation process of the present invention includes the following steps: S1. During the drilling process of the hollow drill rod 100 and drill bit 400, the air compressor is started and compressed air is injected into the dual-channel conversion mechanism 300 provided on the hollow drill rod 100 through the connecting pipe. The air is then lifted and reversed to remove slag through the dual-pipe assembly 200 on the hollow drill rod 100 and the mixer on the hollow drill rod 100. S2. Simultaneously start the grouting pump and inject high-pressure mud into the dual-channel conversion mechanism 300 provided on the hollow drill rod 100 through the connecting pipe, and inject high-pressure mud into the annular grout reservoir 500 on the drill bit 400 through the dual-pipeline assembly 200 on the hollow drill rod 100. S3. High-pressure mud is ejected from the annular mud reservoir 500 through the mud pipe 501 and the mud outlet nozzle 502, which cools the cutting teeth 401 at the bottom of the drill bit 400 and actively washes away the rock cuttings generated by the crushing, so that the rock cuttings quickly enter the mud-carrying pipe 600 of the hollow drill rod 100 and are carried out of the hole by the air-lift reverse circulation flow.

[0027] The specific working principle is as follows: 1) Air-lift slag removal circulation: Compressed air generated by the air compressor is sent to the mixer inside the hollow drill rod 100 through the air duct of the dual-pipe assembly 200 to form a low-density gas-liquid mixture. Under the action of pressure difference, it flows upward and carries the rock cuttings from the bottom of the hole out of the hole.

[0028] 2) Active flushing and cooling circulation: The high-pressure grouting pump pressurizes fresh grout (or grout returned from the settling tank) and delivers it through an independent grout pipe 501 to the annular grout reservoir 500 on the drill bit 400. The annular grout reservoir 500 serves to buffer and evenly distribute the grout. The high-pressure grout is then ejected at high speed from multiple nozzles 502 at the bottom of the grout pipe, directly flushing the cutter teeth 401 of the cutter head and the working face at the bottom of the hole.

[0029] This high-pressure jet: 1) Forced cooling: It acts directly on the high-temperature area of ​​the hob, quickly removes heat, achieves efficient cooling, and greatly extends the hob's life.

[0030] 2) Active flushing and diversion: The rock cuttings generated by the cutter are flushed away from the crushing zone in time, so that they are suspended and flow into the mud carrying the cuttings into the pipe 600 located at the center of the drill bit 400, thereby effectively avoiding repeated crushing and improving drilling efficiency.

[0031] As attached Figures 2 to 5As shown, the hollow drill pipe 100 is provided with a dual-pipeline assembly 200 for simultaneously supplying compressed air and mud on its outer side. A dual-channel conversion mechanism 300 is connected to the dual-pipeline assembly 200. The dual-channel conversion mechanism 300 contains two channels for supplying compressed air or mud, respectively. The two channels are respectively connected to the pipes 201 in the dual-pipeline assembly 200. The dual-channel conversion mechanism 300 is coaxially arranged at the upper end of the hollow drill pipe 100 and is installed and fixed on the power head.

[0032] The dual-channel conversion mechanism 300 includes a rotating body 301, a fixed body 302, and a wear-resistant sleeve 303. The wear-resistant sleeve 303 is sleeved on the outer circumferential wall of the rotating body 301, and the fixed body 302 is sleeved on the outer circumferential wall of the wear-resistant sleeve 303. The rotating body 301 is mounted and fixed on the drive head of the power head and rotates synchronously with the hollow drill rod 100. The fixed body 302 is mounted and fixed on the fixed housing of the power head. Bearings 304 are respectively installed between the outer circumferential walls at the upper and lower ends of the rotating body 301 and the outer circumferential walls at the upper and lower ends of the fixed body 302. Pressure caps 305 are respectively installed on the axial ends of the bearings 304 and the upper and lower ends of the fixed body 302. The pressure caps 305 are fixed on the upper and lower ends of the fixed body 302 by bolts. Two annular channels distributed along the axial direction of the rotating body 301 are provided between the rotating body 301, the wear-resistant sleeve 303, and the fixed body 302.

[0033] The outer circumferential wall of the rotating body 301 is provided with two rings of first fluid grooves 306, and the outer circumferential wall of the wear-resistant sleeve 303 is provided with two rings of second fluid grooves 307. The first fluid grooves 306 and the second fluid grooves 307 are distributed in a one-to-one correspondence and are connected independently. The outer circumferential wall of the rotating body 301 fits into the inner circumferential wall of the wear-resistant sleeve 303 and is sealed by a sealing ring 308. The outer circumferential wall of the wear-resistant sleeve 303 fits into the inner circumferential wall of the fixed body 302 and is sealed by a sealing ring 308. The fixed body 302 is equipped with four connectors 316 for connecting to an external grouting pump or air compressor. The connectors 316 are connected to the second fluid grooves 307, and each second fluid groove 307 has two corresponding connectors 316 that are connected.

[0034] The two rings of first fluid channels 306 and the two rings of second fluid channels 307 are all independent chambers. One chamber is connected to an external air compressor (the connector 316 can connect to one or two depending on the depth and diameter of the pile hole); the other chamber is connected to an external grouting pump (the connector 316 can connect to one or two depending on the depth and diameter of the pile hole). Because the pressure on the external air or liquid varies depending on the depth or diameter of the pile hole, the number of connectors 316 can be flexibly connected according to actual construction needs, which better meets the requirements of deep and large-diameter cast-in-place piles.

[0035] The first fluid tank 306 is divided into an upper fluid tank 309 and a lower fluid tank 310. The lower wall of the upper fluid tank 309 has two first connecting holes 311, and the lower wall of the lower fluid tank 310 has two through holes 312 and two second connecting holes 313. A connecting pipe 314 is installed between the first connecting holes 311 of the upper fluid tank 309 and the through holes 312 of the lower fluid tank 310. A connecting pipe 314 is installed in the second connecting holes 313 of the lower fluid tank 310. All pipes 314 extend beyond the axial direction of the rotating body 301, and all connecting pipes 314 are connected to the pipes 201 in the dual-pipe assembly 200 one by one; the second fluid groove 307 has two rings and is distributed in a one-to-one correspondence with the upper fluid groove 309 and the lower fluid groove 310, and the circumferential groove wall of the second fluid groove 307 has a plurality of equally spaced connecting holes 315, and all connecting holes 315 are connected to the upper fluid groove 309 and the lower fluid groove 310.

[0036] The dual-pipeline assembly 200 includes two pipes for compressed air and two pipes 201 for mud. The two ends of each pipe 201 are respectively mounted and fixed to flanges 101 at both axial ends of the hollow drill rod 100. The main body of each pipe 201 is mounted and fixed to anti-torsion seats 102 in the radial direction of the hollow drill rod 100. The mud pipe 201 is connected to an annular slurry reservoir inside the drill bit connected to the hollow drill rod 100, and the compressed air pipe 201 is connected to a mixer inside the hollow drill rod 100. The mixer is located below the hollow drill rod 100 and is connected to it via an air duct. The grouting pump is a single unit with a flow rate of 10 m³ / h. 3 A grouting pump with a pressure of 2-3 MPa per hour.

[0037] As attached Figure 6 , 7As shown, the upper part of the drill bit 400 is provided with an annular slurry reservoir 500, which is connected to the slurry pipe 201 on the outside of the hollow drill rod 100 for conveying mud. At least two downwardly extending slurry pipes 501 are evenly arranged on the outer circumferential wall of the drill bit 400, and the slurry pipes 501 are connected to the annular slurry reservoir 500. The hollow drill rod 100 extends to the bottom of the drill bit 400 and is fixed. A mud-carrying inflow pipe 600 is provided at the bottom circumferential wall of the hollow drill rod 100, and the mud-carrying inflow pipe 600 is connected to the bottom plate of the drill bit 400. A slurry nozzle 502 is fixed at the bottom end of the slurry pipe 501, and the nozzles of the slurry nozzles 502 are all facing the cutting teeth 401 of the drill bit 400. The slurry nozzle 502 is precisely positioned approximately 5-10 cm above the gap between each pair of cutter teeth 401, with the axis of the slurry outlet tilted downwards and pointing towards the center of the drill bit. This, combined with the slurry pipe 501, ensures that the jet stream precisely covers the cutting area of ​​the cutter head and the initial trajectory of the rock cuttings, achieving optimal cooling and scouring effects.

[0038] The drill bit 400 is hollow inside. The mud and cuttings inflow pipe 600 is located inside the drill bit 400. One end of the mud and cuttings inflow pipe 600 is connected to the inside of the hollow drill rod 100, and the other end is connected to the bottom plate of the drill bit 400. The inlet of the mud and cuttings inflow pipe 600 is located on the side of the hollow drill rod 100.

[0039] The mud-carrying inflow pipe 600 is composed of a vertical pipe 601 and an inclined pipe 602. The vertical pipe 601 is connected to the inclined pipe 602. The vertical pipe 601 is perpendicular to and connected to the bottom plate of the drill bit 400. The inclined pipe 602 is connected to the interior of the hollow drill rod 100 and is inclined along the height direction of the drill bit 400. An inclined plate 603 is provided inside the hollow drill rod 100. The inclined plate 603 is fixed to the inner circumferential wall of the hollow drill rod 100. The inclined plate 603 is located below the wall of the inclined pipe 602, and the slope of the inclined plate 603 is the same as the slope of the inclined pipe 602.

[0040] The annular slurry reservoir 500 is fixed to the upper end of the drill bit 400, and the outer diameter of the annular slurry reservoir 500 is equal to the outer diameter of the drill bit 400. The outer circumferential wall of the drill bit 400 is provided with several equally spaced reinforcing ribs 402, and the diameter of the reinforcing ribs 402 is larger than the diameter of the pipeline 201. The integrated design of the drill bit slurry reservoir 500 and the drill bit 400 body is integrated into one unit, ensuring both pressure resistance and uniform mud distribution.

[0041] The dual-channel conversion mechanism 300, the annular slurry reservoir 500 within the drill bit 400, and the slurry outlet nozzle 502, as described above, offer the following advantages: 1. Significantly Extended Drill Bit Life: Forced cooling of the cutting cutter using high-pressure mud solves the problem of rapid tooth wear caused by high temperatures in traditional processes. Preliminary estimates suggest that, under the same hard rock formation conditions, drill bit life can be extended by more than 30%.

[0042] 2. Significantly improved drilling efficiency: Active flushing promptly removes rock cuttings from the bottom of the borehole, effectively preventing repeated crushing and ensuring that all the energy of the cutting rollers is used to break new rock surfaces. It is estimated that in complex formations, pure drilling efficiency can be increased by 15%-25%.

[0043] 3. Reduced overall construction costs: Extended drill bit life reduces the number of times drill bits need to be replaced, and improved drilling efficiency shortens the hole-forming time. Together, these factors significantly reduce labor, equipment, and time costs, with the estimated cost of single-pile hole formation reduced by 10%-15%.

[0044] 4. Improved hole bottom cleanliness: Active flushing helps to quickly guide rock cuttings to the central inlet, improving the efficiency of cuttings removal and making the hole bottom cleaner. This creates favorable conditions for subsequent hole cleaning and concrete pouring, which is conducive to ensuring the quality of pile formation.

[0045] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An air-lift reverse circulation process, characterized in that: The airlift reverse circulation process includes the following steps: S1. During the drilling process of the hollow drill rod (100) and drill bit (400), the air compressor is started and compressed air is injected into the dual-channel conversion mechanism (300) provided on the hollow drill rod (100) through the connecting pipe. The air is then lifted and reversed to remove slag through the dual-pipe assembly (200) on the hollow drill rod (100) and the mixer on the hollow drill rod (100). S2. Simultaneously start the grouting pump and inject high-pressure mud into the dual-channel conversion mechanism (300) provided on the hollow drill rod (100) through the connecting pipe, and inject high-pressure mud into the annular grout reservoir (500) on the drill bit (400) through the dual-pipeline assembly (200) on the hollow drill rod (100). S3. High-pressure mud is ejected from the annular mud reservoir (500) through the mud pipe (501) and out of the mud nozzle (502), which cools the cutting teeth (401) at the bottom of the drill bit (400) and actively washes away the rock cuttings generated by the crushing, so that the rock cuttings quickly enter the hollow drill rod (100). The mud carrying the cuttings flows into the pipe (600) and is carried out of the hole by the air-lift reverse circulation.

2. A drilling tool device employing the air lift reverse circulation process as described in claim 1, characterized in that: The hollow drill pipe (100) is provided with a dual-pipeline assembly (200) for simultaneously supplying compressed air and mud on its outer side. A dual-channel conversion mechanism (300) is connected to the dual-pipeline assembly (200). The dual-channel conversion mechanism (300) contains two channels for supplying compressed air or mud, respectively. The two channels are connected to the pipes (201) in the dual-pipeline assembly (200) one by one. The dual-channel conversion mechanism (300) is coaxially arranged at the upper end of the hollow drill pipe (100) and installed and fixed on the power head.

3. The drilling tool device according to claim 2, characterized in that: The dual-channel conversion mechanism (300) includes a rotating body (301), a fixed body (302), and a wear-resistant sleeve (303). The wear-resistant sleeve (303) is fitted onto the outer circumferential wall of the rotating body (301), and the fixed body (302) is fitted onto the outer circumferential wall of the wear-resistant sleeve (303). The rotating body (301) is mounted and fixed on the drive head of the power head and rotates synchronously with the hollow drill rod (100). The fixed body (302) is mounted and fixed on the fixed housing of the power head, and the rotating body (301)... Bearings (304) are installed between the outer peripheral walls of the upper and lower ends of the rotating body (301) and the outer peripheral walls of the upper and lower ends of the fixed body (302). A pressure cap (305) is installed on the axial end of the bearing (304) and the upper and lower ends of the fixed body (302). The pressure cap (305) is fixed on the upper and lower ends of the fixed body (302) by bolts. Two annular channels are provided between the rotating body (301), the wear-resistant sleeve (303) and the fixed body (302) along the axial direction of the rotating body (301).

4. The drilling tool device according to claim 3, characterized in that: The outer circumferential wall of the rotating body (301) is provided with two rings of first fluid grooves (306), and the outer circumferential wall of the wear-resistant sleeve (303) is provided with two rings of second fluid grooves (307). The first fluid grooves (306) and the second fluid grooves (307) are distributed in a one-to-one correspondence and communicate with each other independently. The outer circumferential wall of the rotating body (301) is fitted with the inner circumferential wall of the wear-resistant sleeve (303) and sealed by a sealing ring (308). The outer circumferential wall of the wear-resistant sleeve (303) is fitted with the inner circumferential wall of the fixed body (302) and sealed by a sealing ring (308). The fixed body (302) is equipped with four connectors (316) for connecting to the outside grouting pump or air compressor. The connectors (316) communicate with the second fluid grooves (307), and each second fluid groove (307) corresponds to two connectors (316) and they communicate with each other.

5. The drilling tool device according to claim 4, characterized in that: The first fluid tank (306) is divided into an upper fluid tank (309) and a lower fluid tank (310). The lower wall of the upper fluid tank (309) is provided with two first connecting holes (311), and the lower wall of the lower fluid tank (310) is provided with two through holes (312) and two second connecting holes (313). A connecting pipe (314) is installed between the first connecting holes (311) of the upper fluid tank (309) and the through holes (312) of the lower fluid tank (310). A connecting pipe (314) is installed in the second connecting holes (313) of the lower fluid tank (310). All the connecting pipes (314) extend beyond the axial direction of the rotating body (301), and each of the connecting pipes (314) is connected to the pipes (201) in the dual-pipe assembly (200) one by one; the second fluid groove (307) is provided with two rings and is distributed in a one-to-one correspondence with the upper fluid groove (309) and the lower fluid groove (310), and the circumferential groove wall of the second fluid groove (307) is provided with a plurality of equally spaced connecting holes (315), and each of the connecting holes (315) is connected to the upper fluid groove (309) and the lower fluid groove (310).

6. The drilling tool apparatus according to claim 2, characterized in that: The dual-pipeline assembly (200) includes two pipes for compressed air and two pipes for mud. The two ends of the pipes (201) are respectively installed and fixed on the flanges (101) at both axial ends of the hollow drill rod (100). The main body of the pipes (201) is installed and fixed on the anti-torsion seat (102) in the radial direction of the hollow drill rod (100). The pipes (201) for mud are connected to the annular slurry reservoir inside the drill bit connected to the hollow drill rod (100), and the pipes (201) for compressed air are connected to the mixer inside the hollow drill rod (100).

7. The drilling tool device according to claim 2, characterized in that: The upper part of the drill bit (400) is provided with an annular slurry reservoir (500), which is connected to the slurry pipe (201) on the outside of the hollow drill rod (100) for passing mud. At least two downwardly extending slurry pipes (501) are evenly arranged on the outer peripheral wall of the drill bit (400), and the slurry pipes (501) are connected to the annular slurry reservoir (500). The hollow drill rod (100) extends to the bottom of the drill bit (400) and is fixed. A mud-carrying inflow pipe (600) is provided at the bottom peripheral wall of the hollow drill rod (100), and the mud-carrying inflow pipe (600) is connected to the bottom plate of the drill bit (400). A slurry nozzle (502) is fixed at the bottom end of the slurry pipe (501), and the nozzle of the slurry nozzle (502) is facing the cutting teeth (401) of the drill bit (400).

8. The drilling tool apparatus according to claim 7, characterized in that: The drill bit (400) is hollow inside. The mud-carrying pipe (600) is located inside the drill bit (400). One end of the mud-carrying pipe (600) is connected to the inside of the hollow drill rod (100), and the other end is connected to the bottom plate of the drill bit (400). The inlet of the mud-carrying pipe (600) is located on the side of the hollow drill rod (100).

9. The drilling tool apparatus according to claim 8, characterized in that: The mud-carrying inflow pipe (600) is composed of a vertical pipe (601) and an inclined pipe (602). The vertical pipe (601) is connected to the inclined pipe (602). The vertical pipe (601) is perpendicular to and connected to the bottom plate of the drill bit (400). The inclined pipe (602) is connected to the interior of the hollow drill rod (100). The inclined pipe (602) is distributed in an inclined manner along the height direction of the drill bit (400). An inclined plate (603) is provided inside the hollow drill rod (100). The inclined plate (603) is fixed to the inner circumferential wall of the hollow drill rod (100). The inclined plate (603) is located below the pipe wall of the inclined pipe (602). The slope of the inclined plate (603) is the same as the slope of the inclined pipe (602).

10. The drilling tool apparatus according to claim 7, characterized in that: The annular slurry reservoir (500) is fixed to the upper end of the drill bit (400), and the outer diameter of the annular slurry reservoir (500) is equal to the outer diameter of the drill bit (400); the outer circumferential wall of the drill bit (400) is provided with a plurality of reinforcing ribs (402) distributed at equal intervals, and the diameter of the reinforcing ribs (402) is greater than the diameter of the pipeline (201).

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