Hole-forming device and construction method for convection-plastic formation construction

Abstract

The present invention discloses a hole-forming device and method for convection-plastic formation construction, the device comprising a drill rod and a drill bit; a short steel casing is provided above the drill bit, the short steel casing being rotatably connected to the drill rod; a pressure wheel assembly is provided on the short steel casing to prevent the short steel casing from rotating; an upper ring airbag and a lower ring airbag are provided on the outer wall of the short steel casing, the two airbags being connected to an air pump via a first air pipe; a circle of nozzles is provided on the outer wall of the short steel casing, the circle of nozzles being connected to a mixing pipe, the mixing pipe being located inside the short steel casing, the mixing pipe being used to transport a wall-fixing agent solution; the key step of the method is to inflate the upper ring airbag and the lower ring airbag to form an annular closed flow-blocking space, and to spray the wall-fixing agent solution therein. The hole-forming device and method reinforce the convection-plastic formation section by section, can effectively prevent hole collapse, are quick, convenient and labor-saving to operate, and do not require the use of a large pipe-rolling machine.

Description

Technical Field

[0001] The present invention relates to the technical field of pile foundation construction in civil engineering, in particular to a hole-forming device for constructing a fluidized plastic stratum mixed in a conventional soil layer and a hole-forming construction method using the device. Background Art

[0002] When pile foundation construction is carried out in coastal areas of my country, due to topography, geology, climate and other reasons, the soil is often rich in water content, resulting in the frequent inclusion of plastic strata in conventional soil layers. The plastic stratum is a clay layer with a liquid index greater than 1. Since the above-mentioned plastic stratum has low shear strength, high compressibility, low permeability and poor hole wall stability, targeted treatment is required during pile foundation construction. Specifically, before the drill bit and drill rod are drilled, it is necessary to lower the steel casing from the ground to the depth of the plastic stratum to separate the borehole and the plastic stratum, thereby avoiding the collapse of the hole wall. The ordinary soil layer underlying the plastic stratum is drilled normally to the bottom of the hole using drilling tools, and the wall is protected by mud. After the steel cage is inserted, concrete is poured and before it is initially solidified, the steel casing is pulled out to ensure that the hole is formed.

[0003] However, the above-mentioned scheme of inserting and removing steel casing to isolate the fluidized stratum wall is not very effective in actual construction, and has the following shortcomings. First, the fluidized stratum is often located deep underground, such as in an area 30 to 40 meters underground, which requires a steel casing of at least 40 meters long. Obviously, a single section of steel casing cannot reach this length. Generally, 12-meter sections of steel casing are used to extend them section by section. In this way, the process of repeatedly extending when sinking piles and repeatedly disassembling when pulling piles is cumbersome, time-consuming and labor-intensive. Moreover, in order to avoid concave and curling deformation of the steel casing, its wall thickness can only be increased, and steel plates of more than 12 mm are used, which further increases the dead weight of the steel casing, making lifting and insertion more laborious. Moreover, such a long and bulky steel casing is difficult to install. The frictional resistance of the outer soil is huge, and it can only be inserted and pulled out with the help of large equipment such as a pipe rolling machine, which increases the shift cost. In addition, the verticality of the steel casing is difficult to control when it is inserted. Once it is hit crooked, the entire pile will be scrapped. Furthermore, the timing of pulling out is also difficult to control. If the pulling out is too early, the concrete in the hole is still in a plastic state, which may easily lead to quality accidents such as leakage or necking under the active soil pressure of the hole wall. However, if the pulling out is too late, the pile concrete and the steel casing will be fully bonded, which will further increase the difficulty of pulling out. If vibration is used for forced pulling out, it will cause greater disturbance to the pile foundation and the stratum, and may lead to accidents such as broken piles. Summary of the Invention

[0004] A technical problem to be solved by the present invention is to provide a drilling device for the construction of convective plastic formations which can reinforce them section by section during the drilling process without using a full-length steel casing, can effectively avoid hole collapse, is quick, convenient and labor-saving to operate, and does not require the use of a large-scale pipe rolling machine.

[0005] A technical solution of the present invention is to provide a drilling device for convection-plastic formation construction, which includes a drill rod with a scraper-type drill bit at the lower end of the drill rod; a short steel casing is provided above the drill bit, and the short steel casing is connected to a concentric sleeve via a rib plate, and the concentric sleeve is rotatably connected to the drill rod via a thrust bearing; a pressure wheel assembly is provided on the short steel casing for supporting the wall of the borehole to prevent the short steel casing from rotating; an upper ring airbag and a lower ring airbag are provided on the outer wall of the short steel casing, and the outer edges of the above two airbags are provided with rubber strips that, when the airbags are fully inflated, abut against the wall of the borehole for sealing. The above-mentioned two air bags are connected to the air pump through the first air pipe; a circle of multiple nozzles is provided on the outer wall of the short steel casing, and the circle of nozzles is located between the two air bags. The circle of nozzles are all connected to an annular tube, and the inlet of the annular tube is connected to the outlet of a mixing tube. The mixing tube is located in the short steel casing, and the inlet of the mixing tube is respectively connected to the first liquid pipe outlet and the second liquid pipe outlet. The inlet of the first liquid pipe is connected to the mud effect solution pool outside the hole, and the inlet of the second liquid pipe is connected to the water glass solution pool outside the hole. The first liquid pipe is provided with a first stop valve, and the second liquid pipe is provided with a second stop valve.

[0006] Compared with the prior art, the hole-forming device for convective plastic formation construction of the present application has the following advantages.

[0007] First of all, the device changes the wall protection mode. It does not need to adopt the full casing protection from the ground to the plastic layer. Instead, it strengthens the key area, that is, the depth of the plastic layer, in a highly targeted manner. The weakest layer is strengthened. Moreover, the device strengthens layer by layer, with the height of the short steel casing as a standard depth, and only strengthens the borehole wall of a standard depth each time, instead of strengthening the entire borehole wall in a rough manner. With such intensive cultivation, the strengthening effect is good and the operation and construction are more convenient. Specifically, each time within a standard depth, the short steel casing is used as the inner wall. The skeleton supports the hole, and the upper and lower ring air bags are used to separate the annular closed flow-blocking space. In this way, the pressure and dosage of the injected wall-fixing agent can be accurately controlled, and the wall-fixing agent can be accurately delivered at a constant pressure and quantity in a constant volume space to prevent it from being lost from the gap, and to ensure that the wall-fixing agent is evenly and quickly diffused to the hole wall of the drilling section of the standard depth, thereby obtaining the best reinforcement and strengthening effect; and the generation and delivery structure of the wall-fixing agent is also reasonably arranged. After the upper and lower ring air bags are inflated and sealed, the first and second stop valves are opened, so that the mud-fixing solution and the water glass solution can form a wall-fixing agent solution in the mixing tube, and because the mixing tube It is arranged in the short steel casing, close to the nozzle, so it can effectively seize the window period before the wall solidifying agent solution hardens and send it into the annular closed flow-blocking space in time, thereby ensuring the reinforcement effect of the drilled section; from the operational point of view, since there is no need to adopt the full-casing wall protection mode, the process of extending more than 40 meters of steel casing section by section in the prior art is omitted, and the process of disassembling section by section when pulling out is naturally omitted, and the operation is convenient; moreover, compared with the prior art process of using a large-scale pipe rolling machine to overcome the huge side friction resistance to insert and pull out the full casing of about 40 meters in the soil, the short steel casing of the present application that plays the role of wall protection is generally It is 3 to 4 meters long, with short length, light weight and small resistance. It can be clamped on the drill pipe through the thrust bearing and can be easily and smoothly pulled out synchronously with the drill pipe. It only relies on the pile driver of the drill pipe itself to provide power, and there is no need to equip a special pipe rolling machine, which omits the shift fee of large equipment and makes construction convenient and labor-saving. Furthermore, the pressure wheel assembly on the short steel casing can roll smoothly in the axial direction, which is conducive to the lifting and lowering of the drill pipe and the short steel casing, but can provide sufficient circumferential resistance to avoid the rotation of the short steel casing, thereby avoiding the interference of the fluid pipeline in the borehole with the drill pipe, and providing support for the short steel casing and the fluid pipeline.

[0008] Preferably, the device also includes a third liquid pipe, the inlet of the third liquid pipe is connected to the release agent solution pool outside the hole, the outlet of the third liquid pipe is connected to the inlet of the mixing pipe, and the third liquid pipe is provided with a third shut-off valve; the original intention of this design is that after the wall fixing agent solution is injected into the annular closed flow-blocking space for reinforcement, the reinforced hole wall within the standard depth may adhere to each other with the outer wall of the short steel casing. At this time, if drilling directly, the outer wall of the short steel casing may drive the adhered hole wall soil to cause a hole collapse accident. Therefore, before continuing to drill, the release agent is injected to make the outer wall of the short steel casing smoothly separate from the reinforced hole wall of the standard depth, thereby avoiding hole collapse; moreover, the above-mentioned release agent solution flows through the mixing pipe and the annular pipe, and in the meantime washes away the wall fixing agent solution remaining in the mixing pipe, the annular pipe, and the nozzle, to prevent it from hardening and blocking the pipeline, killing two birds with one stone.

[0009] As a gain, a middle ring airbag is also provided on the outer wall of the short steel casing, and a circle of scraping teeth is evenly distributed along the circumference of the outer edge of the middle ring airbag, which scrapes grooves on the wall of the drilled hole when the airbag is fully inflated; the first air pipe includes a main pipe and two branch pipes, and the first port of the air pump is connected to the main pipe of the first air pipe, and the main pipe is connected to the two branch pipes, and the two branch pipes are respectively connected to the upper ring airbag and the lower ring airbag; the second port of the air pump is connected to the middle ring airbag through the second air pipe; the air pump is fixed on the inner wall of the short steel casing.

[0010] First, the structure is combined with the release agent to further optimize the separation effect of the steel casing and the hole wall. Specifically, the upper and lower ring airbags are evacuated and contracted, and the inner concave part is separated from the reinforced hole wall, while the middle ring airbag is inflated and expanded, pushing the hole wall outward, so that the reinforced hole wall is further compressed. Then the middle ring airbag descends with the drill bit and the short steel casing to scrape the reinforced hole wall of the standard depth. The scraping process squeezes the hole wall outward again, further improving the hole wall hardening effect and reducing the chance of hole collapse. In addition, the middle ring The airbag also scrapes multiple grooves on the hole wall, thereby increasing the roughness of the hole wall. After the concrete is poured in the later stage, it can increase the friction resistance of the pile side and further enhance the bearing capacity of the pile body. Furthermore, the middle ring airbag itself serves as a reserve airbag built into the short steel casing, providing exhaust and air storage space for the upper and lower ring airbags, and then completely embeds the gas pipeline and air pump into the short steel casing. This eliminates the need to place the air pump outside the hole, and omits the air pipe extending from the outside of the hole to the short steel casing, thereby reducing the probability of the air pipe being entangled with various other pipelines.

[0011] As a further limitation, the volumes of the upper ring airbag and the lower ring airbag are equal, and the volume of the middle ring airbag is twice that of the lower ring airbag; when the upper ring airbag and the lower ring airbag are fully inflated, their rubber strips are convex to the pressure wheel assembly, and when the upper ring airbag and the lower ring airbag are half inflated, their rubber strips are concave to the pressure wheel assembly; when the middle ring airbag is fully inflated, the scraping teeth are convex to the pressure wheel assembly; when the middle ring airbag is half inflated, the scraping teeth are concave to the pressure wheel assembly. The above-mentioned limitations facilitate precise control and constitute three clear working states: State 1, the upper ring airbag and the lower ring airbag are 100% fully inflated and the middle ring airbag is completely deflated, ensuring that the annular closed flow-blocking space is tightly sealed, facilitating the injection of the wall fixing agent at a constant pressure and quantity; State 2, the three airbags are all inflated to 50%, the rubber strips and scrapers are sufficiently concave, and completely separated from the hole wall, facilitating the normal drilling of the drill rod in ordinary soil layers; State 3, the middle ring airbag is 100% fully inflated and the upper ring airbag and the lower ring airbag are completely deflated, facilitating the complete separation of the upper and lower ring airbags from the reinforced hole wall, and also facilitating the middle ring airbag to push the lower scraper outward to the reinforced hole wall to prevent hole collapse.

[0012] The pressure wheel assembly is preferably composed of four groups, which are distributed in the upper and lower layers. The two groups in the upper layer are located at the zero and six o'clock positions on the upper end of the short steel casing, and the two groups in the lower layer are located at the three and nine o'clock positions on the lower end of the short steel casing; each group of pressure wheel assemblies includes a C-shaped bracket welded to the inner wall of the short steel casing and a square hole that passes through the wall of the short steel casing, and a guide shaft slides in the guide hole of the middle plate of the C-shaped bracket, and a C-shaped wheel seat is fixed to the outer end of the guide shaft, and a top head for clamping the inner mouth of the guide hole is provided at the inner end of the guide shaft, and a compression spring is fitted on the guide shaft, and the two ends of the compression spring are respectively abutted against the middle plate of the C-shaped bracket and the C-shaped wheel seat, and the C-shaped wheel seat is equipped with a pressure wheel, and each pressure wheel extends out of the short steel casing through the square hole of the same group. In this way, the four groups of pressure wheel assemblies are separated into four quadrants, and the circumferential force is balanced, which can more reliably prevent the short steel casing from rotating. The two groups of pressure wheel assemblies on the upper layer are located at the upper end of the short steel casing, ensuring that there are always two groups against the hole wall of the ordinary soil layer or the reinforced soil layer, avoiding the four groups against the fluidized plastic formation, thereby preventing the circumferential constraint of the short steel casing from failing; and the pressure wheel assembly itself, under the action of the spring, can ensure that the pressure is continuously and stably against the hole wall, realizing the automatic outward compensation function of the pressure.

[0013] The connection structure between the drill pipe and the short steel casing is preferably that an annular support plate is welded on the drill pipe, the concentric sleeve of the short steel casing is fixed to the seat ring of the thrust bearing, and the shaft ring of the thrust bearing is fixed to the annular support plate of the drill pipe; the above structure is easy to assemble and can ensure that the drill pipe and the short steel casing are flexible to rotate and stable in support after assembly.

[0014] Another technical problem to be solved by the present invention is to provide a method for drilling holes in convective plastic formations, which can reinforce them section by section during the drilling process without using a full-length steel casing, effectively avoid hole collapse, and is quick, convenient, and labor-saving to operate, without the need for a large-scale pipe rolling machine.

[0015] A technical solution of the present invention is to provide a method for drilling in a convection-plastic formation, the steps of which include:

[0016] a. First, drill normally with the drill bit and drill rod, and use mud to protect the wall until the drill bit reaches the depth of the plastic formation. When the drill rod drills, the pressure rollers of the pressure roller assembly press against the borehole wall to prevent the short steel casing from rotating;

[0017] b. We take the height of the short steel casing as a standard depth and continue drilling a standard depth until the upper ring airbag of the short steel casing reaches the top height of the current fluidized formation, then suspend the drilling process of the drill pipe;

[0018] c. Start the air pump to transfer gas from the middle ring airbag to the upper and lower ring airbags until the upper and lower ring airbags are fully inflated and the middle ring airbag is completely deflated. At this time, the rubber strips of the upper and lower ring airbags are sealed against the borehole wall, forming an annular closed flow-blocking space surrounded by the outer wall of the short steel casing, the upper and lower ring airbags, and the plastic-shaped borehole wall of the borehole section located between the upper and lower airbags;

[0019] d. Open the first stop valve and the second stop valve, so that the first liquid pipe and the second liquid pipe respectively deliver the mud-curing solution and the water glass solution from outside the hole into the mixing pipe inside the short steel casing. The two solutions mix to form a wall-solidifying agent solution, which is sprayed into the annular closed flow-blocking space by the annular pipe and various nozzles. The above spraying process lasts for 60 seconds, causing the plastic hole wall of the drilled section between the upper ring airbag and the lower ring airbag to harden, forming the reinforced hole wall of the standard depth;

[0020] e. Close the first stop valve and the second stop valve, and open the third stop valve to allow the release agent solution to be sprayed from the third liquid pipe through the mixing pipe, the annular pipe and the nozzle, so that the outer wall of the short steel casing is smoothly separated from the wall of the reinforced section of the standard depth;

[0021] f. Start the air pump in reverse to transfer gas from the upper and lower ring airbags to the middle ring airbag until the middle ring airbag is fully inflated and the upper and lower ring airbags are completely deflated. At this time, a circle of scraping teeth of the middle ring airbag abuts against the wall of the reinforced section;

[0022] g. Drive the drill bit and drill pipe downward to a standard depth until the upper ring airbag of the short steel casing reaches the top of the current fluidized formation. Then, suspend drilling. At this time, a circle of scraping teeth of the middle ring airbag scrapes multiple grooves on the wall of the reinforced section of the hole at the previous standard depth.

[0023] h. Repeat steps c to g until the borehole walls of all depths within the plastic formation are reinforced, and then pull the drill bit, drill rod and short steel casing out of the hole.

[0024] Compared with the prior art, the above construction method has the following advantages.

[0025] The above construction method has all the advantages of the above construction equipment, such as there is no need to protect the wall with casing from the ground, but to strengthen it layer by layer; each layer is supported by a short steel casing, assisted by upper and lower ring air bags to form an annular closed flow-blocking space, and the wall-fixing agent is added at a constant volume, pressure and dosage to make it diffuse quickly and evenly without loss, and the reinforcement effect is good; no large machinery is required, and the pile driver's own power can be relied on, which is labor-saving and convenient to operate.

[0026] Moreover, more importantly, the above-mentioned features are combined with each other, promote each other, and benefit each other. For example, the injection of the release agent can not only prevent the wall fixing agent from blocking the pipeline, but also facilitate the separation of the casing and the hole wall; after the release agent is injected, the upper and lower ring airbags will be concave inwards and separate from the reinforced hole wall, while the middle ring airbag will work together to expand outwards and scrape down to squeeze the reinforced hole wall, further reducing the probability of adhesion and collapse, and scrape out the groove body, increasing the pile side friction resistance and pile foundation bearing capacity; at the same time, it also serves as a backup gas storage space for the upper and lower ring airbags, optimizes the built-in gas pipeline, and saves time extending from the ground. The long air pipe; the vertical guide of the pressure wheel on the short steel casing ensures the smooth lifting and lowering of the drill tool, and can constrain the rotation of the short steel casing to avoid interference between the fluid pipeline and the drill pipe, providing support for the short steel casing and the fluid pipeline; the two sets of pressure wheel assemblies on the upper layer are located at the upper end of the short steel casing, always against the hole wall of the hard soil layer, to avoid all four sets against the fluidized stratum and the failure of the circumferential constraint; the mixing pipe is set in the short steel casing, close to the nozzle, to ensure that it is sprayed before hardening, ensuring the reinforcement effect; etc. The organic combination of the above features has jointly achieved the overall technical effect of layer-by-layer reinforcement, convenient operation, good reinforcement effect, no adhesion and collapse of the hole, and increased bearing capacity of the pile foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the hole-forming device for convection-plastic formation construction according to the present invention.

[0028] Figure 2 It is a structural schematic diagram of the hole-forming device for convection-plastic formation construction of the present invention after removing half of the short steel casing.

[0029] Figure 3 It is an enlarged schematic diagram of the liquid delivery pipeline of the pore-forming device for construction in a flow-plastic formation according to the present invention.

[0030] Figure 4 It is an enlarged schematic diagram of the gas transmission pipeline of the pore-forming device for convection-plastic formation construction according to the present invention.

[0031] Figure 5 It is an enlarged schematic diagram of the pressure wheel assembly of the hole-forming device for construction in a flow-plastic formation according to the present invention.

[0032] As shown in the figure, 1. drill pipe, 2. drill bit, 3. short steel casing, 4. rib, 5. concentric sleeve, 6. thrust bearing, 7. annular support plate, 8. C-shaped support seat, 9. square hole, 10. guide shaft, 11. C-shaped wheel seat, 12. mandrel, 13. compression spring, 14. pressure wheel, 15. upper ring airbag, 16. lower ring airbag, 17. rubber strip, 18. middle ring airbag, 19. scraper, 20. first air pipe, 21. air pump, 22. second air pipe, 23. nozzle, 24. annular pipe, 25. mixing pipe, 26. first liquid pipe, 27. second liquid pipe, 28. third liquid pipe. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] like Figures 1 to 5 As shown, the drilling device for convection plastic formation construction of the present invention includes a drill rod 1, and the lower end of the drill rod 1 is a conventional three-edged scraper type drill bit 2.

[0035] A short steel casing 3 is provided above the drill bit 2. The short steel casing 3 is relative to the full casing in the prior art. The full casing is extended section by section, and each section of casing is generally 12 meters. After several sections are extended, it is often as long as thirty or forty meters. The short steel casing 3 of this application is generally 3 to 4 meters, and the word "short" is worthy of its name.

[0036] The short steel casing 3 is connected to a concentric sleeve 5 via ribs 4. In this embodiment, two upper and lower concentric sleeves 5 are provided within the short steel casing 3. Each concentric sleeve 5 is welded to the inner wall of the short steel casing 3 via three ribs 4. Each concentric sleeve 5 is rotatably connected to the drill pipe 1 via a thrust bearing 6. Specifically, an annular support plate 7 is welded to the drill pipe 1. Each concentric sleeve 5 of the short steel casing 3 is fixed to the seat ring of a thrust bearing 6, and the shaft ring of the thrust bearing 6 is fixed to the corresponding annular support plate 7 on the drill pipe 1.

[0037] The short steel casing 3 is provided with a pressure wheel assembly for pressing against the borehole wall to prevent the short steel casing 3 from rotating. There are four sets of pressure wheel assemblies, distributed in two layers, the two sets in the upper layer are located at the circumferential zero and six o'clock positions on the upper end of the short steel casing 3, and the two sets in the lower layer are located at the circumferential three and nine o'clock positions on the lower end of the short steel casing 3. Each set of pressure roller assemblies includes a C-shaped bracket 8 welded to the inner wall of the short steel casing 3 and a square hole 9 that passes through the wall of the short steel casing 3. A guide shaft 10 slides in the guide hole of the middle plate of the C-shaped bracket 8. The outer end of the guide shaft 10 is fixed with a C-shaped wheel seat 11. The inner end of the guide shaft 10 is provided with a head 12 for clamping the inner opening of the guide hole. A compression spring 13 is sleeved on the guide shaft 10. The two ends of the compression spring 13 are respectively in contact with the middle plate of the C-shaped bracket 8 and the C-shaped wheel seat 11. The C-shaped wheel seat 11 is equipped with a pressure roller 14. Each pressure roller 14 extends out of the short steel casing 3 through the square hole 9 of the same set of pressure roller assemblies. The wheel axle of each pressure roller 14 is horizontal.

[0038] The outer wall of the short steel casing 3 is equipped with an upper ring airbag 15 and a lower ring airbag 16. The outer edges of these two airbags are equipped with rubber strips 17, which abut and seal against the borehole wall when the upper ring airbag 15 or the lower ring airbag 16 is fully inflated. The outer wall of the short steel casing 3 is also equipped with a middle ring airbag 18. The outer edge of the middle ring airbag 18 is evenly distributed along the circumference of the circle of scraping teeth 19, which scrape grooves on the borehole wall when the middle ring airbag 18 is fully inflated.

[0039] The upper and lower ring airbags 15 and 16 are connected to an air pump 21 via a first air pipe 20. Specifically, the first air pipe 20 comprises a main pipe and two branch pipes. The first port of the air pump 21 is connected to the main pipe of the first air pipe 20, which in turn is connected to the two branch pipes, which are in turn connected to the upper and lower ring airbags 15 and 16, respectively. The second port of the air pump 21 is connected to the middle ring airbag 18 via a second air pipe 22. The air pump 21 is fixed to the inner wall of the short steel casing 3.

[0040] The volumes of the upper ring airbag 15 and the lower ring airbag 16 are equal, and the volume of the middle ring airbag 18 is twice that of the lower ring airbag 16; when the upper ring airbag 15 and the lower ring airbag 16 are fully inflated, their rubber strips 17 are convex to the pressure wheel assembly, and when the upper ring airbag 15 and the lower ring airbag 16 are half inflated, their rubber strips 17 are concave to the pressure wheel assembly; when the middle ring airbag 18 is fully inflated, the scraping teeth 19 are convex to the pressure wheel assembly; when the middle ring airbag 18 is half inflated, the scraping teeth 19 are concave to the pressure wheel assembly.

[0041] The outer wall of the short steel casing 3 is provided with a circle of multiple nozzles 23. The circle of nozzles 23 is located between the upper ring airbag 15 and the lower ring airbag 16. The circle of nozzles 23 is connected to various liquid reservoirs located on the ground via a liquid infusion pipeline. The liquid infusion pipeline is used to transport the wall-fixing agent solution. Specifically, the liquid infusion pipeline includes an annular pipe 24, a mixing pipe 25, a first liquid pipe 26, and a second liquid pipe 27. The circle of nozzles 23 are all connected to the annular pipe 24. The inlet of the annular pipe 24 is connected to the outlet of the mixing pipe 25. The mixing pipe 25 is located within the short steel casing 3. The inlet of the mixing pipe 25 is connected to the outlet of the first liquid pipe 26 and the outlet of the second liquid pipe 27 respectively. The inlet of the first liquid pipe 26 is connected to the mud-reducing solution pool outside the hole, and the inlet of the second liquid pipe 27 is connected to the water glass solution pool outside the hole. The first liquid pipe 26 is provided with a first stop valve, and the second liquid pipe 27 is provided with a second stop valve. In this embodiment, the weight ratio of the gram-nixie powder to water in the gram-nixie solution is 4 / 9, and the weight ratio of water glass to water in the water glass solution is 1 / 5. The gram-nixie solution and the water glass solution are mixed in a weight ratio of 20 / 1.

[0042] The infusion pipeline further includes a third liquid pipe 28 , the inlet of the third liquid pipe 28 is connected to the release agent solution pool outside the hole, the outlet of the third liquid pipe 28 is also connected to the inlet of the mixing pipe 25 , and the third liquid pipe 28 is provided with a third stop valve.

[0043] As is common sense, the device also includes a main controller such as a PCB or PLC chip. The first, second, and third hydraulic pumps are respectively provided in the first, second, and third liquid pipes 26, 27, and 28. The aforementioned stop valves, air pumps, and hydraulic pumps are all signal-connected to the main controller.

[0044] The method for drilling holes in a plastic formation using the device of the present invention comprises the following steps.

[0045] a. Drilling is first performed normally with the drill bit 2 and drill rod 1 in the ordinary soil layer overlying the fluidized formation, using mud wall protection until the drill bit 2 reaches the depth of the fluidized formation. For example, in this embodiment, the depth of the fluidized formation ranges from 30 meters to 42 meters. Drilling is then suspended when the drill bit 2 reaches a depth of 30 meters. As the drill rod 1 drills, the individual rollers 14 of the roller assembly press against the borehole wall, preventing the short steel casing 3 from rotating.

[0046] b. We take the height of the short steel casing 3 as a standard depth. For example, if the short steel casing 3 in this embodiment is 4 meters high, then a standard depth is 4 meters.

[0047] The drilling is continued to a standard depth such as 4 meters until the upper ring air bag 15 of the short steel casing 3 reaches the top height of the stratum which is currently in a fluidized state, and then the drilling process of the drill pipe 1 is suspended.

[0048] c. Start the air pump 21 and transport gas from the middle ring airbag 18 to the upper ring airbag 15 and the lower ring airbag 16 until the upper ring airbag 15 and the lower ring airbag 16 are fully inflated and the middle ring airbag 18 is completely deflated. At this time, the rubber strips 17 of the upper ring airbag 15 and the lower ring airbag 16 are sealed against the wall of the borehole, forming an annular closed flow-blocking space surrounded by the outer wall of the short steel casing 3, the upper ring airbag 15, the lower ring airbag 16, and the plastic-shaped hole wall of the borehole section located between the upper and lower airbags.

[0049] d. Open the first stop valve and the second stop valve, so that the first liquid pipe 26 and the second liquid pipe 27 respectively deliver the mud-curing solution and the water glass solution from outside the hole into the mixing pipe 25 in the short steel casing 3. The two solutions are mixed to form a wall-solidifying agent solution, which is sprayed into the annular closed flow-blocking space by the annular pipe 24 and each nozzle 23. The above spraying process lasts for 60 seconds, causing the plastic hole wall of the drilled section between the upper ring airbag 15 and the lower ring airbag 16 to harden, forming the reinforced hole wall of the standard depth.

[0050] e. Close the first stop valve and the second stop valve, and open the third stop valve to allow the release agent solution to be ejected from the third liquid pipe 28 through the mixing pipe 25, the annular pipe 24 and the nozzle 23, so that the outer wall of the short steel casing 3 is smoothly separated from the wall of the reinforced section of the standard depth; at the same time, the wall-fixing agent solution remaining in the mixing pipe 25 and the annular pipe 24 is washed away to prevent it from hardening and blocking the pipeline.

[0051] f. Start the air pump 21 in reverse to transport gas from the upper ring airbag 15 and the lower ring airbag 16 to the middle ring airbag 18 until the middle ring airbag 18 is fully inflated and the upper ring airbag 15 and the lower ring airbag 16 are completely deflated. At this time, a circle of scraping teeth 19 of the middle ring airbag 18 is in contact with the wall of the reinforced section.

[0052] g. Drive the drill bit 2 and the drill rod 1 to continue drilling downward to a standard depth until the upper ring airbag 15 of the short steel casing 3 reaches the top height of the current plastic formation, that is, the top height of the hole wall that has not been reinforced. For example, if the top elevation of the plastic formation is 30 meters and it has been reinforced to a standard depth of 4 meters, then the top height of the current plastic formation is 26 meters. Then, drilling is suspended. At this time, a circle of scraping teeth 19 of the middle ring airbag 18 scrapes out multiple grooves on the wall of the reinforced section of the hole at the previous standard depth. The grooves are convenient for increasing the surface roughness of the pile side and improving the side friction resistance of the pile body when pouring concrete in the later stage.

[0053] h. Repeat steps c to g until the borehole walls of all depths within the plastic formation are reinforced. Then continue drilling normally in the ordinary soil layer underlying the plastic formation and use mud to protect the walls until the bottom of the hole is reached. Then pull the drill bit 2, drill rod 1 and short steel casing 3 out of the hole.

Claims

1. A drilling device for convective plastic formation construction, comprising a drill rod with a scraper-type drill bit at the lower end of the drill rod; characterized in that: A short steel casing is provided above the drill bit, and the short steel casing is connected to a concentric sleeve through a rib plate, and the concentric sleeve is rotatably connected to the drill pipe through a thrust bearing; a pressure wheel assembly is provided on the short steel casing for resisting the wall of the borehole to prevent the short steel casing from rotating; an upper ring air bag and a lower ring air bag are provided on the outer wall of the short steel casing, and the outer edges of the above two air bags are provided with rubber strips that seal against the wall of the borehole when the air bags are fully inflated, and the above two air bags are connected to the air pump through a first air pipe; a circle of multiple nozzles is provided on the outer wall of the short steel casing, and the circle of nozzles is located between the two air bags, and the circle of nozzles are all connected to an annular pipe, the inlet of the annular pipe is connected to the outlet of a mixing pipe, and the mixing pipe is located in the short steel casing, and the inlet of the mixing pipe is connected to the first liquid pipe outlet and the second liquid pipe outlet respectively, the first liquid pipe inlet is connected to the mud effect solution pool outside the hole, and the second liquid pipe inlet is connected to the water glass solution pool outside the hole, the first liquid pipe is provided with a first stop valve, and the second liquid pipe is provided with a second stop valve; The hole forming device also includes a third liquid pipe, the inlet of the third liquid pipe is connected to the release agent solution pool outside the hole, the outlet of the third liquid pipe is connected to the inlet of the mixing pipe, and the third liquid pipe is provided with a third stop valve; The outer wall of the short steel casing is also provided with a middle ring airbag. The outer edge of the middle ring airbag is evenly distributed along the circumference with a circle of scraping teeth that scrape grooves on the borehole wall when the airbag is fully inflated. The first air pipe includes a main pipe and two branch pipes. The first port of the air pump is connected to the main pipe of the first air pipe, and the main pipe is connected to the two branch pipes, which are respectively connected to the upper ring airbag and the lower ring airbag. The second port of the air pump is connected to the middle ring airbag through the second air pipe. The air pump is fixed to the inner wall of the short steel casing. There are four groups of pressure wheel assemblies, distributed in the upper and lower layers. The two groups on the upper layer are located at the zero and six o'clock positions on the upper end of the short steel casing, and the two groups on the lower layer are located at the three and nine o'clock positions on the lower end of the short steel casing; each group of pressure wheel assemblies includes a C-shaped bracket welded on the inner wall of the short steel casing and a square hole that passes through the wall of the short steel casing. A guide shaft slides in the guide hole of the middle plate of the C-shaped bracket, and a C-shaped wheel seat is fixed to the outer end of the guide shaft. The inner end of the guide shaft is provided with a head for clamping the inner mouth of the guide hole. A compression spring is fitted on the guide shaft, and the two ends of the compression spring are respectively abutted against the middle plate of the C-shaped bracket and the C-shaped wheel seat. The C-shaped wheel seat is equipped with a pressure wheel, and each pressure wheel extends out of the short steel casing through the square hole of the same group.

2. The hole-forming device for convective plastic formation construction according to claim 1, characterized in that: The volumes of the upper and lower ring airbags are equal, and the volume of the middle ring airbag is twice that of the lower ring airbag; when the upper and lower ring airbags are fully inflated, their rubber strips are convex to the pressure wheel assembly, and when the upper and lower ring airbags are half inflated, their rubber strips are concave to the pressure wheel assembly; when the middle ring airbag is fully inflated, the scraping teeth are convex to the pressure wheel assembly; when the middle ring airbag is half inflated, the scraping teeth are concave to the pressure wheel assembly.

3. The hole-forming device for convective plastic formation construction according to claim 1, characterized in that: An annular supporting plate is welded on the drill pipe, the concentric sleeve of the short steel casing is fixed to the seat ring of the thrust bearing, and the shaft ring of the thrust bearing is fixed to the annular supporting plate of the drill pipe.

4. A method for drilling construction using the device according to any one of claims 1 to 3, characterized in that: The steps include: a. First, drill normally with the drill bit and drill rod, and use mud to protect the wall until the drill bit reaches the depth of the plastic formation. When the drill rod drills, the pressure rollers of the pressure roller assembly press against the borehole wall to prevent the short steel casing from rotating; b. Take the height of the short steel casing as a standard depth and continue drilling for a standard depth until the upper ring airbag of the short steel casing reaches the top height of the current fluidized formation, then suspend the drilling process of the drill pipe; c. Start the air pump to transfer gas from the middle ring airbag to the upper and lower ring airbags until the upper and lower ring airbags are fully inflated and the middle ring airbag is completely deflated. At this time, the rubber strips of the upper and lower ring airbags are sealed against the borehole wall, forming an annular closed flow-blocking space surrounded by the outer wall of the short steel casing, the upper and lower ring airbags, and the plastic-shaped borehole wall of the borehole section located between the upper and lower airbags; d. Open the first stop valve and the second stop valve, so that the first liquid pipe and the second liquid pipe respectively deliver the mud-curing solution and the water glass solution from outside the hole into the mixing pipe inside the short steel casing. The two solutions mix to form a wall-solidifying agent solution, which is sprayed into the annular closed flow-blocking space by the annular pipe and various nozzles. The above spraying process lasts for 60 seconds, causing the plastic hole wall of the drilled section between the upper ring airbag and the lower ring airbag to harden, forming the reinforced hole wall of the standard depth; e. Close the first stop valve and the second stop valve, and open the third stop valve to allow the release agent solution to be sprayed from the third liquid pipe through the mixing pipe, the annular pipe and the nozzle, so that the outer wall of the short steel casing is smoothly separated from the wall of the reinforced section of the standard depth; f. Start the air pump in reverse to transfer gas from the upper and lower ring airbags to the middle ring airbag until the middle ring airbag is fully inflated and the upper and lower ring airbags are completely deflated. At this time, a circle of scraping teeth of the middle ring airbag abuts against the wall of the reinforced section; g. Drive the drill bit and drill pipe downward to a standard depth until the upper ring airbag of the short steel casing reaches the top of the current fluidized formation. Then, suspend drilling. At this time, a circle of scraping teeth of the middle ring airbag scrapes multiple grooves on the wall of the reinforced section of the hole at the previous standard depth. h. Repeat steps c to g until the borehole walls of all depths within the plastic formation are reinforced, and then pull the drill bit, drill rod and short steel casing out of the hole.

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