Pipe curtain drilling structure capable of improving pore-forming quality

Abstract

The application discloses a pipe curtain drilling structure capable of improving pore-forming quality, and belongs to the technical field of tunnel construction, which comprises a spiral drill rod, a down-the-hole hammer fixedly connected to one end of the spiral drill rod, and a down-the-hole drill bit installed on the down-the-hole hammer; a pipe curtain casing pipe is coaxially installed on the outer side of the down-the-hole hammer, and the pipe curtain casing pipe is radially spaced apart from the down-the-hole hammer and the spiral drill rod; one end of the pipe curtain casing pipe is connected to the down-the-hole hammer; the spiral drill rod is connected to a pipe curtain drilling machine; the pipe curtain casing pipe and the spiral drill rod rotate at the same frequency; the other end of the pipe curtain casing pipe extends along the axial direction of the spiral drill rod; and the outer diameter of the pipe curtain casing pipe is the same as the outer diameter of the pipe curtain steel pipe during pipe feeding. The drilling structure can be used to solve the problems that the drilling direction is easily downwardly deflected in the conventional drilling method, and the pipe feeding is difficult due to the mismatch between the drilling diameter and the steel pipe diameter.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, specifically relating to a pipe curtain drilling structure that can improve the quality of borehole formation. Background Technology

[0002] Pipeline jacking construction methods can be categorized into "conventional drilling" and "casing drilling" based on whether drilling and pipe delivery are synchronized. Conventional drilling is often the preferred method for pipeline jacking due to its advantages such as simple process, lightweight equipment, convenient equipment selection, fast construction progress, low cost, and strong adaptability to geological formations. However, its disadvantages are also significant, including: a large drill rod slenderness ratio, heavy drill bit, large drill bit oscillation, uneven geological formations leading to borehole deviation, low construction quality, and a tendency for borehole collapse, drill bit jamming, and difficulty in pipe delivery in soft formations. Casing drilling, on the other hand, avoids these problems in generally soft formations, ensuring construction quality and reducing ground displacement and surface settlement during construction. Its main disadvantages are greater limitations in equipment selection, difficulty in correcting deviations, and slower construction progress. Based on the advantages and disadvantages of the two methods, and considering both construction quality and economy, according to engineering experience, conventional drilling is mainly suitable for soft rock, relatively soft rock and other generally weak strata, while casing drilling is mainly used for soft soil strata and other relatively poor strata.

[0003] For ultra-long pipe jacking construction, the longer the pipe jacking length, the more difficult it is to control its construction accuracy. During the drilling process, as the length increases, the downward deflection of the drill rod due to gravity also increases, and coupled with drill bit vibration, it is easy to cause the borehole to deviate downwards. In view of this, there is an urgent need to propose a pipe jacking drilling structure that can improve the quality of borehole formation. This structure can solve the problems of downward deviation of the drilling direction and difficulty in pipe entry caused by mismatch between the borehole diameter and the steel pipe diameter in conventional drilling methods, without increasing construction costs or replacing pipe jacking equipment. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a pipe curtain drilling structure that can improve the quality of hole formation, thereby solving the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention discloses a pipe curtain drilling structure capable of improving hole formation quality, comprising a spiral drill rod and a down-the-hole (DH) impactor fixedly connected to one end of the spiral drill rod, wherein a DH drill bit is mounted on the DH impactor; a pipe curtain sleeve is coaxially mounted on the outer side of the DH impactor, the pipe curtain sleeve being radially spaced from the DH impactor and the spiral drill rod, one end of the pipe curtain sleeve being connected to the DH impactor, the spiral drill rod being connected to a pipe curtain drilling rig, the pipe curtain sleeve rotating at the same frequency as the spiral drill rod, the other end of the pipe curtain sleeve extending along the axial direction of the spiral drill rod, and the outer diameter of the pipe curtain sleeve being the same as the outer diameter of the pipe curtain steel pipe during pipe feeding.

[0007] Furthermore, the pipe curtain sleeve includes several arc-shaped plates evenly distributed along the circumference. The edges of the arc-shaped plates are provided with T-shaped slots, which penetrate the arc-shaped plates along their length. Adjacent arc-shaped plates are connected by elastic connecting plates, the length of which is the same as that of the arc-shaped plates. Both ends of the elastic connecting plates have T-shaped protrusions corresponding to the T-shaped slots. The spiral drill rod is equipped with an expansion drive mechanism for the pipe curtain sleeve.

[0008] Furthermore, the elastic connecting plate is made of elastic material, and a cavity is formed in the center of the elastic connecting plate. When the T-shaped protrusion is squeezed by the T-shaped slot, the middle part of the elastic connecting plate can expand out from the gap between two adjacent arc-shaped plates.

[0009] Furthermore, a conical plate is fixed to the end of the arc-shaped plate away from the down-the-hole impactor. The expansion drive mechanism includes a conical boss, which is slidably sleeved on the outside of the auger rod. The large end of the conical boss is connected to a limiting plate via a telescopic device, and the limiting plate is fixedly connected to the auger rod. The small end of the conical boss engages with the inclined surface of the conical plate.

[0010] Furthermore, a T-shaped slider is fixed to one end of the arc-shaped plate near the down-the-hole impactor, and an end plate is fixed to the down-the-hole impactor. The end face of the end plate is provided with a T-shaped groove along the radial direction to cooperate with the T-shaped slider.

[0011] Furthermore, both the tapered boss and the end plate are provided with through holes, and the axis of the through holes is parallel to the axis of the auger drill rod.

[0012] Furthermore, a sleeve is rotatably provided on the outer side of the down-the-hole impactor, and a scraper and a fan blade are fixedly connected to both ends of the sleeve, respectively. The scraper is evenly distributed along the circumference of the sleeve, and the scraper is in contact with the surface of the end plate facing the down-the-hole drill bit.

[0013] Furthermore, the auger drill rod includes several segmented drill rods and helical blades fixed on the segmented drill rods. One end of the segmented drill rod and one end of the down-the-hole impactor are formed with slots, and the other end of the segmented drill rod is formed with a plug that mates with the slots.

[0014] The beneficial effects of this invention are as follows:

[0015] 1) This invention provides a casing drilling structure that improves borehole quality. The casing primarily serves to protect the borehole wall, preventing disturbance and rockfall during drilling. Another function is that the casing diameter is larger than the drill pipe, providing better rigidity and preventing drill pipe bending, thus improving borehole quality. Because the casing is made with a radially expandable and deformable structure, after drilling, the conical boss is axially pushed, causing the casing steel pipe to deform outwards. This provides pre-deformation space to the borehole wall, allowing the drill bit to avoid disturbance to the borehole wall during drill bit retraction.

[0016] 2) In this invention application, the casing also wraps around the down-the-hole impactor, which can act as a stabilizer and reduce the downward deviation of the borehole caused by drill bit vibration during drilling.

[0017] 3) The diameter of the pipe curtain sleeve is the same as that of the pipe curtain steel pipe, which can avoid the problem of difficulty in pipe entry caused by the mismatch between the drilling diameter and the diameter of the steel pipe in the later construction.

[0018] 4) The process of pulling back impact drill tools (auger drill rod, down-the-hole impactor, down-the-hole drill bit and outer casing) can achieve the effect of hole cleaning.

[0019] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0020] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0021] Figure 1 This is a schematic diagram of the drilling structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the structure of the pipe curtain sleeve of the present invention. Figure 1 ;

[0023] Figure 3 for Figure 2 Enlarged view at point A;

[0024] Figure 4 This is a schematic diagram of the structure of the pipe curtain sleeve of the present invention. Figure 2 ;

[0025] Figure 5 This is a cross-sectional view of the pipe curtain sleeve;

[0026] Figure 6 for Figure 5 Enlarged view at point B;

[0027] Figure 7 This is a schematic diagram of the sleeve structure;

[0028] Figure 8 This is a schematic diagram of the structure of the conical boss;

[0029] Figure 9 This is a schematic diagram of a segmented drill pipe.

[0030] The following are labeled in the attached diagram: 1. Spiral drill rod; 2. Down-the-hole impactor; 3. Down-the-hole drill bit; 4. Tube curtain casing; 5. Arc plate; 6. T-slot; 7. Elastic connecting plate; 8. T-protrusion; 9. Cavity; 10. Conical plate; 11. Conical boss; 12. Telescopic device; 13. Limiting plate; 14. T-slider; 15. End plate; 16. T-slot; 17. Through hole; 18. Sleeve; 19. Scraper; 20. Fan blade; 21. Segmented drill rod; 22. Spiral blade; 23. Slot; 24. Insert rod. Detailed Implementation

[0031] like Figures 1-9 As shown, this invention discloses a pipe curtain drilling structure that can improve hole formation quality. It includes a spiral drill rod 1 and a down-the-hole impactor 2 fixedly connected to one end of the spiral drill rod 1. The pipe curtain drilling rig is mounted on a construction platform, and the spiral drill rod 1 is connected to the pipe curtain drilling rig and rotates via the rig. A down-the-hole drill bit 3 is mounted on the down-the-hole impactor 2. The spiral drill rod 1 drives the down-the-hole impactor 2 and the down-the-hole drill bit 3 to rotate together. After the pipe curtain drilling rig moves, drilling of the pipe curtain installation hole is achieved.

[0032] The down-the-hole impactor 2 is coaxially fitted with a pipe curtain sleeve 4, which is also fitted onto the outside of the auger rod 1. The pipe curtain sleeve 4 is radially spaced from the down-the-hole impactor 2 and the auger rod 1 to facilitate mud removal. One end of the pipe curtain sleeve 4 is connected to the down-the-hole impactor 2 and can follow the auger rod 1 and the down-the-hole impactor 2 in drilling. The auger rod 1 is connected to a pipe curtain drilling rig, and the pipe curtain sleeve 4 rotates in sync with the auger rod 1. The other end of the pipe curtain sleeve 4 extends axially along the auger rod 1. When not expanding, the outer diameter of the pipe curtain sleeve 4 is the same as the outer diameter of the pipe curtain steel pipe used for pipe feeding, which avoids the problem of difficulty in pipe feeding later due to the mismatch between the drilling diameter and the diameter of the steel pipe used in later construction.

[0033] The present invention incorporates a casing 4, the main function of which is to protect the borehole wall after drilling, preventing rock mass disturbance and rockfall during the drilling process. Another function of the casing 4 is to prevent drill rod bending. Since the diameter of the casing 4 is larger than that of the auger drill rod 1, it has better rigidity, thus improving the quality of the borehole formation.

[0034] In this embodiment, the pipe curtain sleeve 4 includes three arc-shaped plates 5 evenly distributed along the circumference. Each arc-shaped plate 5 has T-shaped slots 6 on both sides of its edges. The T-shaped slots 6 penetrate the arc-shaped plate 5 along its length. Adjacent arc-shaped plates 5 are connected by elastic connecting plates 7. The elastic connecting plates 7 are made of rubber material and have the same length as the arc-shaped plates 5. T-shaped protrusions 8 corresponding to the T-shaped slots 6 are formed at both ends of the elastic connecting plates 7. When the distance between the arc-shaped plates 5 increases, the elastic connecting plates 7 can also expand in time to fill the gaps. The spiral drill rod 1 is equipped with an expansion drive mechanism for the pipe curtain sleeve 4, which drives the pipe curtain sleeve 4 to expand slightly. This allows for pre-deformation space to be applied to the borehole wall, thereby avoiding the drill bit and preventing the drill bit from disturbing the borehole wall when the drill bit is pulled back.

[0035] In this embodiment, the elastic connecting plate 7 is made of elastic material, and a cavity 9 is formed in the center of the elastic connecting plate 7. When the T-shaped protrusion 8 is squeezed by the T-shaped groove 6, the middle part of the elastic connecting plate 7 can expand out from the gap between two adjacent arc-shaped plates 5. It can follow the outward expansion of the arc-shaped plates 5 in a timely manner, so that the expansion of the tube curtain sleeve 4 in all directions is more uniform.

[0036] In this embodiment, a conical plate 10 is fixed to the end of the arc-shaped plate 5 away from the down-the-hole impactor 2. The conical plate 10 is arranged radially along the pipe curtain sleeve 4. The expansion drive mechanism includes a conical boss 11, which is slidably sleeved on the outside of the auger drill rod 1. The large end of the conical boss 11 is connected to a limiting plate 13 through a telescopic device 12, and the limiting plate 13 is fixedly connected to the auger drill rod 1. The small end of the conical boss 11 engages with the inclined surface of the conical plate 10. Since the pipe curtain steel pipe is made with a structure that can expand and deform radially, after drilling is completed, the pipe curtain steel pipe is deformed outward by axially pushing the conical boss 11. This provides pre-deformation space to the borehole wall, thereby avoiding the drill bit and preventing the drill bit from disturbing the borehole wall when the drill bit is pulled back.

[0037] In this embodiment, a T-shaped slider 14 is fixed to the end of the arc-shaped plate 5 near the down-the-hole impactor 2, and an end plate 15 is fixed to the down-the-hole impactor 2. The end face of the end plate 15 has a T-shaped groove 16 that mates with the T-shaped slider 14 along the radial direction. This groove is used to guide the arc-shaped plate 5 radially during expansion.

[0038] In this embodiment, both the conical boss 11 and the end plate 15 are provided with through holes 17. The axis of the through holes 17 is parallel to the axis of the spiral drill rod 1 and can be used for mud removal.

[0039] In this embodiment, a sleeve 18 is rotatably provided on the outer side of the down-the-hole hammer 2. A scraper 19 and a fan blade 20 are fixedly connected to both ends of the sleeve 18. The fan blade 20 can rotate under the impact of mud and water. The scraper 19 is evenly distributed along the circumference of the sleeve 18. The scraper 19 contacts the surface of the end plate 15 facing the down-the-hole drill bit 3. The fan blade 20 drives the scraper 19 to rotate through the sleeve 18, thereby scraping off the silt on the end plate 15 to ensure that the mud and water can be discharged smoothly during construction.

[0040] In this embodiment, the auger drill rod 1 includes several segmented drill rods 21 and helical blades 22 fixed on the segmented drill rods 21. The segmented drill rods 21 are sequentially spliced ​​along the axial direction to form a whole. One end of each segmented drill rod 21 and one end of the down-the-hole impactor 2 form a slot 23, and the other end of each segmented drill rod 21 forms a plug 24 that mates with the slot 23. This facilitates the installation of the auger drill rod 1. By selecting different numbers of segmented drill rods 21, the overall length of the auger drill rod 1 can also be changed, thus allowing its application in different construction scenarios.

[0041] Before drilling with a pipe curtain, the pipe curtain drilling device that improves the quality of the borehole needs to be fabricated, including the following steps:

[0042] S1: Connect the previous standard length segmented drill rod 21 to the down-the-hole impactor 2 into a whole. The joint is connected by bolts and welding so that it can rotate at the same frequency as the auger drill rod 1.

[0043] S2: Measure the total length of the auger rod 1 and down-the-hole impactor 2 after they are connected as a whole, and calculate the length of the outer casing sleeve 4 by taking into account the dimensions of the end joints and the down-the-hole drill bit 3.

[0044] S3: Based on the calculated length of the outer tube curtain sleeve 4, manufacture the outer tube curtain sleeve 4.

[0045] S4: Place the tube curtain sleeve 4 onto the auger rod 1 and the down-the-hole impactor 2, leaving only the frontmost down-the-hole drill bit 3 exposed, and connect the tube curtain sleeve 4 to the down-the-hole impactor 2.

[0046] Furthermore, in step S1 above, bolt holes are provided at both ends of the auger rod 1 and at the tail end of the down-the-hole impactor 2. The size of the front end of the auger rod 1 is slightly smaller than the size of the tail end of the down-the-hole impactor 2, and the tail end of the down-the-hole impactor 2 can fit over the front end of the auger rod 1.

[0047] Furthermore, in step S1 above, the joint is constructed using a combination of bolts and welding, with bolts as the primary method and welding as a secondary method, to ensure that the auger rod 1 and the down-the-hole impactor 2 do not rotate or misalign with each other.

[0048] Furthermore, in step S2 above, the length of the tube curtain sleeve 4 must be sufficient to cover the length range of the first section of the tube curtain sleeve 4 and the down-the-hole impactor 2, leaving only the front down-the-hole drill bit 3 exposed.

[0049] Furthermore, in step S4 above, the gap between the casing 4 and the down-the-hole impactor 2 is relatively large, ensuring that the casing 4 can rotate at the same frequency as the auger rod 1 during the rotary drilling process.

[0050] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A pipe-coil drilling structure capable of improving borehole quality, characterized in that: The system includes a auger drill rod and a down-the-hole (DH) impactor fixedly connected to one end of the auger drill rod, with a DH drill bit mounted on the impactor. A tubular casing is coaxially mounted on the outer side of the impactor, with a radial gap between the tubular casing, the impactor, and the auger drill rod. One end of the tubular casing is connected to the impactor. A tubular drilling rig is connected to the auger drill rod, and the tubular casing rotates at the same frequency as the auger drill rod. The other end of the tubular casing extends axially along the auger drill rod. The outer diameter of the tubular casing... The outer diameter of the pipe curtain steel pipe is the same as that of the pipe during pipe feeding; the pipe curtain sleeve includes several arc-shaped plates evenly distributed along the circumference, and the edges of the arc-shaped plates are provided with T-shaped grooves. The T-shaped grooves penetrate the arc-shaped plates along the length direction of the arc-shaped plates. Adjacent arc-shaped plates are connected by elastic connecting plates. The length of the elastic connecting plates is the same as the length of the arc-shaped plates. The two ends of the elastic connecting plates form T-shaped protrusions corresponding to the T-shaped grooves; the spiral drill rod is equipped with an expansion drive mechanism for the pipe curtain sleeve.

2. The pipe curtain drilling structure according to claim 1, which can improve the hole formation quality, is characterized in that: The elastic connecting plate is made of elastic material and has a cavity in the center. When the T-shaped protrusion is squeezed by the T-shaped slot, the middle part of the elastic connecting plate can expand out from the gap between two adjacent arc plates.

3. The pipe curtain drilling structure according to claim 2, which can improve the hole formation quality, is characterized in that: A conical plate is fixed to the end of the arc-shaped plate away from the down-the-hole impactor. The expansion drive mechanism includes a conical boss, which is slidably sleeved on the outside of the auger rod. The large end of the conical boss is connected to a limiting plate via a telescopic device, and the limiting plate is fixedly connected to the auger rod. The small end of the conical boss engages with the inclined surface of the conical plate.

4. A pipe curtain drilling structure according to claim 3 that can improve the quality of hole formation, characterized in that: A T-shaped slider is fixed to one end of the arc-shaped plate near the down-the-hole impactor. An end plate is fixed to the down-the-hole impactor, and a T-shaped groove that mates with the T-shaped slider is formed on the end face of the end plate along the radial direction.

5. A pipe curtain drilling structure according to claim 4, characterized in that: Both the conical boss and the end plate are provided with through holes, and the axis of the through holes is parallel to the axis of the auger drill rod.

6. A pipe curtain drilling structure according to claim 5, characterized in that: A sleeve is rotatably mounted on the outer side of the down-the-hole impactor. A scraper and a fan blade are fixedly connected to both ends of the sleeve, respectively. The scraper is evenly distributed along the circumference of the sleeve, and the scraper is in contact with the surface of the end plate facing the down-the-hole drill bit.

7. A pipe-coil drilling structure according to any one of claims 1-6, characterized in that: The auger drill rod includes several segmented drill rods and helical blades fixed on the segmented drill rods. One end of the segmented drill rod and one end of the down-the-hole impactor are formed with slots, and the other end of the segmented drill rod is formed with a plug that mates with the slots.

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