Floor directional long hole horizontal section breakage prevention device and method

Abstract

The present application relates to the technical field of geological exploitation, and more particularly to a floor directional long borehole horizontal section breakage prevention device and method, comprising: drill pipes, provided with a plurality of, the plurality of drill pipes are sequentially combined and cooperate with a directional drilling rig to perform long borehole construction of a horizontal section among coal seams; a back-reaming drill bit, detachably arranged at the end of the drill pipe initially entering the soil; a grouting pipe group; and a breakage prevention assembly. The present application can, in a variable-diameter reaming operation, first spray and consolidate the hole wall of a long borehole opened among the coal seams, and use a metal sleeve to support the breakage-prone area, to a certain extent, resist the deformation of the rock mass around the hole wall of the long borehole, effectively solve the problem of misalignment and deformation, or even direct breakage of the local area of the directional long borehole horizontal section under the middle area of the protective layer working face, caused by the uneven deformation of the floor after the geological fracture zone and the extraction of dynamic stress unloading during the mining process of the working face.

Description

Technical Field

[0001] This invention relates to the field of geological mining technology, and in particular to a device and method for preventing breakage of the horizontal section of a long directional borehole in the bottom plate. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Currently, under the condition of close-range outburst coal seam clusters, in addition to the gas control of the coal seam itself, the mining of the protective layer also faces the challenge of gas inrush from adjacent seams leading to exceeding limits. At present, the technology of constructing directional long boreholes in the middle of the protected layer below the protective layer to intercept and extract gas from the protected layer has achieved good application results.

[0004] However, during the mining process, the uneven deformation of the geological fracture zone and the bottom plate after the mining stress was unloaded caused local displacement deformation or even direct breakage of the horizontal section of the directional long borehole below the middle area of ​​the protective layer working face, thus affecting the construction effect of the horizontal directional long borehole. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned shortcomings by providing a device and method for preventing breakage of the horizontal section of a long directional drilling hole in the base plate.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a device for preventing breakage of the horizontal section of a long directional drilling hole in the base plate, comprising:

[0007] Multiple drill rods are provided. These drill rods are combined in sequence and used in conjunction with directional drilling equipment to construct long horizontal boreholes between coal seams. One end of the long borehole closest to the directional drilling equipment is designated as the entry point, and the other end is designated as the exit point.

[0008] A re-reaming bit is detachably mounted at the end of the drill rod initially inserted into the soil. It is used to enter from the soil exit point to follow the re-drilling of the drill rod and to enlarge the long borehole by changing its diameter.

[0009] The grouting pipe assembly is detachably located at the end of the re-reaming drill bit away from the drill rod, and is used to grout and solidify the borehole wall of the long borehole with variable diameter.

[0010] An anti-breakage component is installed outside the grouting pipe assembly to support and reinforce a designated area as the grouting pipe assembly enters the long borehole with a variable diameter.

[0011] Furthermore, the grouting pipe assembly includes an inner pipe and an outer pipe coaxially sleeved from the inside to the outside. A connector is provided on one end of the inner pipe near the reaming drill bit. The connector is hollow inside and communicates with the inner pipe. Two or more nozzles are evenly arranged on the outer periphery of the connector.

[0012] When the inner tube rotates, it will uniformly spray slurry onto the wall of the long borehole with a variable diameter through two or more nozzles evenly distributed around the outer periphery of the joint.

[0013] Furthermore, a transmission component a is provided at one end of the inner tube and the outer tube that are connected to drive the inner tube and the outer tube to rotate synchronously;

[0014] The transmission component a includes an outer toothed ring sleeved on the outer wall of the inner tube and close to one end of the connector, and an inner toothed ring coaxially disposed on the inner wall of the outer tube. A toothed post is fitted between the outer toothed ring and the inner toothed ring, and the toothed post is adapted to rotate and connect to the end face of the connector.

[0015] Furthermore, the anti-breakage component includes a metal sleeve supported on the wall of the long drilled hole with a variable diameter, and a synchronous expansion mechanism that is fitted on the metal sleeve and expands the metal sleeve with a variable diameter.

[0016] The synchronous expansion mechanism includes a movable sleeve slidably disposed on the outer wall of the outer tube, and multiple sets of wedge groups a located on the movable sleeve and centrally symmetrically distributed. Each wedge group a is composed of two or more first wedge blocks and is evenly distributed along the length direction of the movable sleeve. A second wedge block is provided on the inclined surface of each first wedge block. Multiple second wedge blocks arranged along the length direction of the movable sleeve constitute a wedge group b. An arc plate is fixed to the outer end of the wedge group b. The number of arc plates is the same as that of the wedge group a. Multiple arc plates are combined to form a "petal" structure. The outer wall of each arc plate is in contact with the inner wall of the metal sleeve.

[0017] Furthermore, a support ring a is slidably disposed on the movable sliding sleeve at one end near the arc plate. The support ring a is provided with the same number of sliding grooves as the arc plate. A slider is provided on the arc plate that moves radially along the movable sliding sleeve. The slider is slidably disposed in cooperation with the sliding grooves.

[0018] Furthermore, the anti-breakage component also includes a transmission component b disposed on the outer tube and used to drive the movable sliding sleeve to move;

[0019] The transmission assembly b includes a support ring b extended at the end of the movable sliding sleeve and a fixed ring adjacent to and spaced apart on one side of the support ring b. A screw and a guide rod are respectively provided on both sides of the fixed ring. A section of the screw is connected to the support ring b, and a section of the guide rod is slidably guided to a corresponding position on the support ring b.

[0020] Furthermore, a transmission component c is provided at the outer end of the fixed ring;

[0021] The transmission assembly c includes a gear one disposed on the outer wall of the outer tube and a gear two that is connected to and engaged with the gear one and disposed outside the screw. The inner side of the end face of the gear two is provided with an outer ring and an inner ring that are coaxially sleeved. The inner wall of the outer ring is uniformly provided with a plurality of wedge-shaped spaces. A spring is provided in each wedge-shaped space along the tangent of the inner ring. A roller is provided on the end of the spring near the inner ring. The inner ring is sleeved and fixed to the outer wall of the screw.

[0022] When the outer tube rotates counterclockwise under the power of the directional drilling rig, the gear one and the gear two are engaged to drive the gear two to rotate clockwise. At this time, the roller is pushed towards the narrow end of the wedge-shaped space under the action of friction and the spring, locking the outer ring and the inner ring, thereby driving the screw threaded on the inner ring to rotate synchronously.

[0023] When the outer tube rotates clockwise, the outer ring will rotate counterclockwise with the gear, pushing the roller towards the wide end of the wedge-shaped space, releasing the lock between the outer ring and the inner ring, allowing the outer ring to spin freely while the inner ring does not move.

[0024] Furthermore, a telescopic cover is provided on the screw and in the section between the support ring a and the support ring b. A cleaning block is provided on the support ring b corresponding to the end face of the support ring a and in the position where the guide rod passes through and slides. The cleaning block is used to scrape off the sand and rock debris attached to the surface of the guide rod.

[0025] Furthermore, each structure included in the transmission assembly c is covered with a dustproof shell.

[0026] The anti-breakage method, applied to the anti-breakage device for the horizontal section of the directional long drilled hole in the base plate, specifically includes the following steps:

[0027] S1. Analyze the lithological characteristics between coal seam groups, establish a numerical model, and determine the reasonable arrangement of directional long boreholes and easily fractured areas based on the deformation and pressure relief and permeability enhancement characteristics at different locations between coal seam groups.

[0028] S2, the directional drilling rig equipment is positioned and used in conjunction with multiple drill rods to carry out directional long hole construction in the target area;

[0029] S3, at the soil exit point, remove the drill bit from the corresponding drill rod, replace and combine the back reaming drill bit and the grouting pipe assembly, continue to use the directional drilling machine, back drill multiple sequentially combined drill rods from the soil exit point to the soil entry point, and enlarge the diameter of the long borehole through the back reaming drill bit;

[0030] S4, the high-pressure grouting pump is positioned, and the inner tube, in conjunction with the joint and two or more nozzles evenly distributed on the joint, is used to uniformly grout and solidify the borehole wall of the long borehole during the rotation of the inner tube.

[0031] S5, for the easily broken area determined in step S1, during the drilling back of the moving drill rod, the anti-breakage component outside the outer tube is moved to the target easily broken area. At this time, the drill rod is rotated in the opposite direction, and the multiple evenly distributed arc plates are expanded outward simultaneously, so that the metal sleeve is plastically deformed and closely attached to the hole wall of the long drill hole for support and reinforcement.

[0032] S6. After the above operations are completed, breakage sampling is carried out in the easily broken areas and the results are recorded to provide data support for the next stage of directional long drilling construction and improvement of anti-breakage technology.

[0033] The beneficial effects of this invention are reflected in:

[0034] This invention, through the installation of grouting pipe assemblies and anti-breakage components, enables the pre-grouting consolidation of the borehole wall of long boreholes drilled between coal seams during variable-diameter borehole enlargement operations. It also provides support for easily breakable areas using metal sleeves, thus resisting rock deformation around the borehole wall to a certain extent. This effectively solves the problem of localized displacement deformation or even direct breakage of the horizontal section of the directional long borehole below the central area of ​​the protective layer working face due to uneven deformation of the floor after geological fracture zones and dynamic stress unloading during mining. Furthermore, through the installation of transmission components a, b, and c, grouting consolidation and the precise release of expansion metal sleeves are simultaneously performed during borehole enlargement, following the drill rod and in cooperation with the directional drilling rig, achieving effective support and reinforcement of easily breakable areas of the borehole wall. Attached Figure Description

[0035] Figure 1 This is a perspective view of the overall structure of an embodiment of the present invention.

[0036] Figure 2 This is a three-dimensional structural diagram of an embodiment of the present invention from an exploded perspective;

[0037] Figure 3This is a perspective view of the related structures assembled on the grout tube assembly according to an embodiment of the present invention.

[0038] Figure 4 This is a three-dimensional structural view from an exploded perspective of the related structures assembled on the grouting tube assembly according to an embodiment of the present invention.

[0039] Figure 5 This is a three-dimensional structural diagram of an anti-breakage component according to an embodiment of the present invention, viewed from an explosion perspective.

[0040] Figure 6 This is a three-dimensional structural diagram of an anti-breakage component according to another explosion perspective of an embodiment of the present invention;

[0041] Figure 7 This is a perspective view of the metal sleeve according to an embodiment of the present invention.

[0042] Figure 8 This is a planar structural view of a transmission component c according to an embodiment of the present invention;

[0043] Figure 9 This is a three-dimensional structural view of the connector assembled on the inner tube and the transmission component a according to an embodiment of the present invention, taken from an exploded perspective.

[0044] Figure 10 This is a three-dimensional structural view of the connector assembled on the inner tube and the transmission component a, according to another exploded view of an embodiment of the present invention.

[0045] In the picture:

[0046] 1. Drill pipe; 2. Reamer bit; 3. Anti-breakage component; 31. Metal sleeve; 32. Synchronous expansion mechanism; 321. Movable sliding sleeve; 322. First wedge block; 323. Second wedge block; 324. Arc plate; 325. Support ring a; 326. Slide groove; 327. Slider; 33. Support ring b; 34. Fixed ring; 35. Screw; 36. Guide rod; 37. Gear one; 371. Gear two; 372. Outer ring; 373. Inner ring; 374. Wedge space; 375. Spring; 376. Roller; 4. Inner tube; 41. Connector; 42. Nozzle; 5. Outer tube; 6. External gear ring; 61. Internal gear ring; 62. Gear column; 7. Telescopic cover; 8. Cleaning column block; 9. Dustproof shell. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Please see Figure 1-10 This invention discloses a fracture prevention device for the horizontal section of a long directional borehole in a base plate, which is applied to the fracture-prone area of ​​a long directional borehole and provides fracture prevention protection, including:

[0049] Drill rod 1, multiple drill rods 1 are arranged in sequence and cooperate with directional drilling equipment to carry out long horizontal drilling construction between coal seams. The end of the long drill hole near the directional drilling equipment is set as the soil entry point, and the other end of the long drill hole is set as the soil exit point.

[0050] The back-reaming drill bit 2 is detachably mounted at the end of the drill rod 1 when it is initially inserted into the soil. It is used to enter from the soil exit point to follow the back-drilling of the drill rod 1 and to reduce the diameter of the long borehole.

[0051] The grouting pipe assembly is detachably mounted on the end of the re-reaming drill bit 2 away from the drill rod 1, and is used to grout and solidify the borehole wall of the long borehole with variable diameter.

[0052] The anti-breakage component 3 is disposed outside the grouting pipe assembly and is used to follow the grouting pipe assembly into the long borehole with a variable diameter to support and reinforce the designated area.

[0053] In practice, multiple sequential combinations are used, and with the start of the directional drilling rig, multiple drill rods 1 are used to construct directional horizontal long boreholes in the coal seam group. The boreholes enter from the marked entry point and exit at the exit point. The drill bit on the drill rod 1 at the exit point is then removed, and bolts are used to sequentially connect and lock the reaming drill bit 2 and grouting pipe assembly. With the start of the directional drilling rig, the reaming drill bit 2 drives the drill rod 1 to re-drill and enlarge the borehole. During this re-drilling and enlargement, the grouting pipe assembly is used to first spray grout to solidify the borehole wall of the long borehole drilled between coal seams. The anti-fracture component 3 supports the easily fractured areas, resisting rock deformation around the borehole wall to a certain extent. This effectively solves the problem of localized displacement deformation or even direct fracture in the horizontal section of the directional long borehole below the central area of ​​the protective layer working face due to uneven deformation of the bottom plate after geological fracture zones and dynamic stress unloading during mining.

[0054] It should be noted that a probe head and a host computer electrically connected to the probe head are installed on the drill rod 1. The probe head can follow the drill rod 1 as it moves along the horizontally oriented long borehole, projecting at least three reference marks onto the borehole wall and acquiring borehole wall images. The at least three reference marks will form a reference surface. At this time, the host computer will receive the borehole wall images sent by the probe head and extract the reference surface contained in the borehole wall images. Based on multiple frames of borehole wall images and the corresponding offset vectors of the borehole wall images, a borehole wall image of the oriented long borehole is constructed, so that the construction personnel can monitor the actual position of the drill rod 1 within the borehole wall at all times.

[0055] In one embodiment, the grouting pipe assembly includes an inner pipe 4 and an outer pipe 5 coaxially sleeved from the inside to the outside. A connector 41 is provided on one end of the inner pipe 4 near the back expansion drill bit 2. The connector 41 is hollow inside and communicates with the inner pipe 4. Two or more nozzles 42 are evenly arranged on the outer periphery of the connector 41.

[0056] When the inner tube 4 rotates, it sprays grout evenly onto the borehole wall of the long borehole through two or more nozzles 42 evenly distributed around the outer circumference of the joint 41. This design, using a coaxial sleeve assembly of the inner tube 4 and outer tube 5, allows the inner tube 4 to rotate relative to the joint 4 during drilling when the drill rod 1, reaming bit 2, and grouting pipe assembly are started and drilled back. At this time, the joint 41 installed on the inner tube 4 near the reaming bit 2, and the two or more nozzles 42 evenly slotted around the outer circumference of the joint 41, spray grout evenly onto the borehole wall and solidify it.

[0057] It should be noted that aluminate quick-setting agents (such as sodium aluminate) will be added to the cement grout used in conjunction with the grouting pipe assembly to accelerate the hydration of tricalcium aluminate, quickly generate ettringite, and shorten the initial setting time to 3-5 minutes.

[0058] In one embodiment, a transmission component a is provided at one end of the inner tube 4 and the outer tube 5 that are connected to each other for driving the inner tube 4 and the outer tube 5 to rotate synchronously;

[0059] The transmission assembly a includes an external toothed ring 6 sleeved on the outer wall of the inner tube 4 and near one end of the connector 41, and an internal toothed ring 61 coaxially disposed on the inner wall of the outer tube 5. A toothed column 62 is fitted between the external toothed ring 6 and the internal toothed ring 61, and the toothed column 62 is adapted to rotate and connect to the end face of the connector 41. With this design, through the external toothed ring 6 sleeved on the outer wall of the inner tube 4 and the internal toothed ring 61 welded to the inner wall of the outer tube 5, wherein the meshing surface between the external toothed ring 6 and the internal toothed ring 61 is connected to the toothed column 62, when the inner tube 4 rotates with the drill rod 1, the meshing of the external toothed ring 6, the toothed column 62 and the internal toothed ring 61 will cause the outer tube 5 to rotate relative to the inner tube 4, achieving the effect of synchronously driving the rotation of the inner tube 4 and the outer tube 5 formed on the grouting pipe assembly.

[0060] In one embodiment, the anti-breakage component 3 includes a metal sleeve 31 supported on the wall of the long drilled hole with a variable diameter, and a synchronous expansion mechanism 32 that is fitted on the metal sleeve 31 and expands the metal sleeve 31 with a variable diameter.

[0061] The synchronous expansion mechanism 32 includes a movable sleeve 321 slidably disposed on the outer wall of the outer tube 5, and multiple sets of wedge groups a located on the movable sleeve 321 and symmetrically distributed at the center. Each wedge group a is composed of two or more first wedge blocks 322 and is evenly distributed along the length direction of the movable sleeve 321. A second wedge block 323 is provided on the inclined surface of each first wedge block 322. Multiple second wedge blocks 323 arranged along the length direction of the movable sleeve 321 constitute a wedge group b. An arc plate 324 is fixed at the outer end of the wedge group b. The number of arc plates 324 is the same as that of the wedge group a. Multiple arc plates 324 are combined to form a "petal" structure. The outer wall of each arc plate 324 is in contact with the inner wall of the metal sleeve 31. This design allows the movable sleeve 321, which is slidably connected to the outer wall of the outer tube 5, and multiple sets of wedge groups a, each composed of a first wedge block 322, which are bolted to the movable sleeve 321, to push the movable sleeve 321 along the length of the outer tube 5 when it is subjected to force and moves horizontally. By utilizing the inclined surfaces of the first wedge block 322 and the second wedge block 323, the wedge group b, composed of the second wedge block 323, moves perpendicular to the pushing direction of the movable sleeve 321. This causes the arc plate 324, which is bolted to the outer end of the wedge group b, to move radially outward along the movable sleeve 321, achieving an effect similar to the unfolding of multiple arc plates 324. This allows the metal sleeve 31 to fit against the hole wall after plastic deformation and expansion, effectively supporting and reinforcing the hole wall of the long drilled hole.

[0062] It should be noted that the metal sleeve 31 is made of high-ductility metal (such as low-carbon steel, stainless steel, titanium alloy) or composite material, and the outer surface is coated with a rubber coating (such as NBR, FKM) to enhance the sealing performance.

[0063] In one embodiment, a support ring a325 is slidably disposed on the movable sleeve 321 near one end of the arc plate 324. The support ring a325 has the same number of grooves 326 as the arc plate 324. The arc plate 324 has a slider 327 that moves radially along the movable sleeve 321 and is limited in its movement. The slider 327 is slidably disposed in cooperation with the grooves 326. With this design, the support ring a325 that slides relative to the movable sleeve 321, the multiple evenly distributed grooves 326 welded on the support ring a325, and the slider 327 welded to the cross section of each arc plate 324, the relative sliding of the grooves 326 and the slider 327, can limit the linear movement of the arc plate 324 along the radial direction of the movable sleeve 321 during the "petal-like" unfolding operation of the arc plate 324, effectively ensuring the expansion effect of the metal sleeve 31.

[0064] In one embodiment, the anti-breakage component 3 further includes a transmission component b disposed on the outer tube 5 and used to drive the movable sliding sleeve 321 to move;

[0065] The transmission assembly b includes a support ring b33 extended at the end of the movable sleeve 321 and a fixed ring 34 adjacent to and spaced apart on one side of the support ring b33. A screw 35 and a guide rod 36 are respectively provided on both sides of the fixed ring 34. A section of the screw 35 is connected to the support ring b33, and a section of the guide rod 36 is slidably guided to a corresponding position on the support ring b33. This design allows the screw 35 installed on the fixed ring 34 to be driven by the integrally formed support ring b33 at the end of the movable sleeve 321 and the circumferentially slotted and limited support on the outer wall of the outer tube 5. The screw 35 is threadedly connected to the support ring b33, causing the support ring b33 and the integrally formed movable sleeve 321 to move linearly along the length of the outer tube 5 under the limitation of the guide rod 36 on the other side, thus transmitting torque. This, in conjunction with wedge groups a and b, expands and supports the metal sleeve 31.

[0066] In one embodiment, a transmission component c is provided at the outer end of the fixed ring 34;

[0067] The transmission assembly c includes a gear 37 disposed on the outer wall of the outer tube 5 and a gear 371 that is connected to the gear 37 and disposed outside the screw 35. The inner side of the end face of the gear 371 is provided with an outer ring 372 and an inner ring 373 that are coaxially sleeved. The inner wall of the outer ring 372 is provided with a plurality of wedge-shaped spaces 374 evenly distributed. A spring 375 is disposed in each wedge-shaped space 374 along the tangent of the inner ring 373. A roller 376 is disposed on the end of the spring 375 near the inner ring 373. The inner ring 373 is sleeved and fixed to the outer wall of the screw 35.

[0068] When the outer tube 5 rotates counterclockwise under the power of the directional drilling rig, the gear 371 rotates clockwise through the cooperation of the gear 371 and the gear 372. At this time, the roller 376 is pushed towards the narrow end of the wedge-shaped space 374 under the action of friction and the spring 375, locking the outer ring 372 and the inner ring 373, thereby driving the screw 35 passing through the inner ring 373 to rotate synchronously.

[0069] When the outer tube 5 rotates clockwise, the outer ring 372 will rotate counterclockwise with the gear 371, causing the roller 376 to be pushed towards the wide end of the wedge-shaped space 374, releasing the lock between the outer ring 372 and the inner ring 373. The outer ring 372 will rotate freely, and the inner ring 373 will not move. This design, by mounting a fixed gear 37 on the outer wall of the outer tube 5 and a gear 371 meshing with the gear 37 on the screw 35 at a corresponding position, transmits torque to drive the gear 371 to rotate when the gear 37 rotates with the outer tube 5. At this time, the outer ring 372 and inner ring 373, which are coaxially mounted on the inner side of the end face of the gear 371, will lock and release the outer ring 372 and inner ring 373 under the structure of the spring 375 and roller 376 and in conjunction with the narrow and wide ends of the wedge-shaped space 374 machined on the inner side of the outer ring 372. This allows the metal sleeve 31 to be released or not released in two rotation directions, so as to expand the metal sleeve 31 in the target area of ​​the easily broken area.

[0070] It should be noted that gear 371 and outer ring 372 are manufactured using an integral molding process.

[0071] In one embodiment, a telescopic cover 7 is provided on a portion of the screw 35 located between the support ring a325 and the support ring b33. A cleaning block 8 is provided on the support ring b33 corresponding to the end face of the support ring a325 and located at the position where the guide rod 36 passes through. The cleaning block 8 is used to scrape away sand and rock debris adhering to the surface of the guide rod 36. This design effectively protects the screw 35 and the guide rod 36 by installing the telescopic cover 7 on the portion of the screw 35 located between the support ring a325 and the support ring b33, and the cleaning block 8 on the support ring b33 at the position where the guide rod 36 passes through, preventing sand and rock debris from entering the transmission structure and accelerating wear, effectively preventing jamming, and ensuring normal transmission performance.

[0072] In one embodiment, each structure included in the transmission assembly c is externally covered with a dustproof shell 9. This design, by installing the dustproof shell 9 on the outside of each structure included in the transmission assembly c, and by fixing the dustproof shell 9 to the outer end of the fixing ring 34 with bolts, can effectively protect each structure included in the transmission assembly c, preventing sand, gravel, and rock fragments from entering and affecting its transmission performance.

[0073] The anti-breakage method, applied to the anti-breakage device for the horizontal section of the directional long drilled hole in the base plate, specifically includes the following steps:

[0074] S1. Analyze the lithological characteristics between closely spaced coal seam groups and establish a numerical model accordingly. The length of the horizontal directional long borehole is 300~500m. Study the deformation and pressure relief and permeability enhancement characteristics of the directional long boreholes at different locations between coal seam groups, determine the reasonable arrangement of the directional long boreholes, and identify the displacement mutation point (displacement exceeding 30% of the horizontal section borehole diameter) under the condition of this stratum as the easily fractured area under normal mining conditions.

[0075] S2, the directional drilling rig equipment is positioned and used in conjunction with multiple drill rods 1 to carry out directional long borehole construction in the target area, and the structural area and fracture zone through which the horizontal section of the directional long borehole is constructed are divided into areas prone to breakage under abnormal conditions.

[0076] S3, at the soil exit point, remove the drill bit from the corresponding drill rod 1, and replace and combine the back-reaming drill bit 2 and the grouting pipe assembly. Continue to use the directional drilling equipment to back-drill multiple sequentially combined drill rods 1 from the soil exit point to the soil entry point. Enlarge the diameter of the long borehole by 30% to 50% (for example, from Φ94mm to Φ120 to 150mm) through the back-reaming drill bit 2. Increase the contact buffer space between the borehole and the coal and rock mass to ensure that ≥60% of the effective extraction channel cross-sectional area can still be maintained when interlayer displacement of ≤50mm occurs.

[0077] S4, the high-pressure grouting pump is positioned, and the inner tube 4, in conjunction with the connector 41 and two or more nozzles 42 evenly distributed on the connector 41, uniformly grouts and solidifies the borehole wall during the rotation of the inner tube 4. The type of grout is selected according to the characteristics of the fracture (such as single-component cement grout or cement-water glass double-component grout). The first grouting adopts the principle of "small amount, multiple times, low pressure, slow injection", and the pressure is controlled below 1.5-2.0 MPa. The second grouting is carried out after the initial setting of the first grouting. High pressure (2-5 MPa) is applied to force the grout to penetrate into the small fractures, improve the density of the space around the borehole construction, and enhance the borehole's ability to resist shear deformation.

[0078] S5, for the easily broken area determined in step S1, during the back-drilling of the drill rod 1, the anti-breakage component 3 outside the outer tube 5 is moved to the target easily broken area. At this time, the drill rod 1 is rotated in the opposite direction, and the multiple evenly distributed arc plates 324 are expanded outward simultaneously, so that the metal sleeve 31 is plastically deformed and closely attached to the hole wall of the long drill hole for support and reinforcement.

[0079] S6. After the above operations are completed, breakage sampling is carried out in the easily broken areas and the results are recorded to provide data support for the next stage of directional long drilling construction and improvement of anti-breakage technology.

[0080] To further clarify, before establishing a numerical model, it is necessary to determine the coal seam spacing (e.g., 5~20m), interlayer lithology (mudstone, sandstone, etc.), and thickness distribution through core drilling and well logging data. In addition, rock sample mechanical parameters such as compressive strength (UCS), elastic modulus (E), Poisson's ratio (ν), cohesion (c), and internal friction angle (φ) should be obtained through laboratory testing. Weak interlayers should be tested and analyzed in detail (e.g., the softening coefficient of mudstone).

[0081] In establishing numerical models, based on lithological characteristics, appropriate models (such as FLAC3D, UDEC, PFC) are selected, and their parameters are assigned values. For example, for coal seams: the Mohr-Coulomb model, with parameters such as c=1.5 MPa, φ=30°, E=3 Gpa; for weak interlayers: the strain softening model, with parameters such as c=1 MPa (residual 0.5 MPa), φ=25°; for hard rock strata: the elastic or Hoek-Brown model, with parameters such as UCS=50 MPa, E=20 GPa.

[0082] Directional borehole layout and working condition simulation: Directional boreholes with diameters of 100-200mm are set in the model and arranged along different strata between coal seams. For example, Scheme 1: boreholes are located 2m below the upper coal seam floor (within a weak interlayer); Scheme 2: boreholes are located between two coal seams (in a hard rock stratum); Scheme 3: boreholes are located close to the lower coal seam roof (stress concentration zone). A step-by-step excavation method is adopted: First, initial equilibrium → upper coal seam mining → stress redistribution (monitoring borehole deformation); Second, lower coal seam mining → analysis of pressure relief and permeability enhancement effects (permeability changes).

[0083] Deformation and pressure relief enhancement characteristics analysis, based on key monitoring indicators (such as borehole deformation: radial displacement (ΔD), focusing on ΔD>30% of the borehole diameter (e.g., borehole diameter 150mm, abrupt change threshold 45mm); stress evolution: vertical stress reduction rate (pressure relief effect, e.g., >30% is effective); permeability change: the enhancement effect is calculated through the pore pressure-permeability coupling model), extract the layers corresponding to displacement abrupt change points (ΔD>30% of the borehole diameter), and mark them as easily fractured areas.

[0084] Model validation and optimization: compare microseismic monitoring data, borehole inspection results and simulated displacement distribution, and calibrate model parameters (such as adjusting the c and φ values ​​of weak interlayers).

[0085] Furthermore, the core of numerical models lies in the accuracy of lithological parameters and the rationality of boundary conditions, which require repeated calibration based on engineering experience.

[0086] The electrical components described in this article are controlled automatically by a controller. The controller circuit can be implemented by a person skilled in the art through simple programming. The power supply is also common knowledge in the field. Furthermore, since this application is mainly used to protect mechanical devices, the control method and circuit connection will not be explained in detail here.

[0087] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0088] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0089] Additionally, "multiple" refers to two or more.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for preventing breakage of the horizontal section of a long directional drill hole in a base plate, characterized in that, include: Drill rod (1), multiple drill rods (1) are arranged in sequence and cooperate with directional drilling equipment to carry out long horizontal drilling construction between coal seam groups. The end of the long drill hole near the directional drilling equipment is set as the soil entry point, and the other end of the long drill hole is set as the soil exit point. The back-reaming drill bit (2) is detachably mounted at the end of the drill rod (1) when it is initially inserted into the soil. It is used to enter from the soil exit point to follow the back-drilling of the drill rod (1) and to reduce the diameter of the long borehole. The grouting pipe assembly is detachably mounted on the end of the re-expansion drill bit (2) away from the drill rod (1) and is used to grout and solidify the hole wall of the long borehole with variable diameter. The grouting pipe assembly includes an inner pipe (4) and an outer pipe (5) coaxially sleeved from the inside to the outside. A connector (41) is provided on one end of the inner pipe (4) near the back expansion drill bit (2). The connector (41) is hollow inside and communicates with the inner pipe (4). Two or more nozzles (42) are evenly arranged on the outer periphery of the connector (41). When the inner tube (4) rotates, it will spray slurry evenly onto the wall of the long borehole with a variable diameter through two or more nozzles (42) evenly distributed on the outer periphery of the joint (41). The anti-breakage component (3) is set outside the grouting pipe group and is used to follow the grouting pipe group into the long borehole with a variable diameter to support and reinforce the designated area. The anti-breakage component (3) includes a metal sleeve (31) supported on the wall of the long drill hole with a variable diameter, and a synchronous expansion mechanism (32) fitted on the metal sleeve (31) and expanding the metal sleeve (31) with a variable diameter. The synchronous expansion mechanism (32) includes a movable sleeve (321) slidably disposed on the outer wall of the outer tube (5), and multiple sets of wedge groups a located on the movable sleeve (321) and centrally symmetrically distributed. Each wedge group a is composed of two or more first wedge blocks (322) and is evenly distributed along the length direction of the movable sleeve (321). Each first wedge block (322) has a second wedge block (323) fitted on its inclined surface. Multiple second wedge blocks (323) arranged along the length direction of the movable sleeve (321) constitute a wedge group b. An arc plate (324) is fixed at the outer end of the wedge group b. The number of arc plates (324) is the same as that of the wedge group a. Multiple arc plates (324) are combined to form a "petal" structure. The outer wall of each arc plate (324) is in contact with the inner wall of the metal sleeve (31).

2. The anti-breakage device for the horizontal section of the directional long drilling of the base plate according to claim 1, characterized in that: A transmission component a is provided at one end of the inner tube (4) and the outer tube (5) that are connected to each other for driving the inner tube (4) and the outer tube (5) to rotate synchronously; The transmission assembly a includes an outer toothed ring (6) sleeved on the outer wall of the inner tube (4) and close to one end of the connector (41) and an inner toothed ring (61) coaxially disposed on the inner wall of the outer tube (5). A toothed column (62) is provided between the outer toothed ring (6) and the inner toothed ring (61), and the toothed column (62) is adapted to rotate and connect to the end face of the connector (41).

3. The anti-breakage device for the horizontal section of the directional long drilling of the base plate according to claim 1, characterized in that: A support ring a (325) is slidably disposed on the movable sliding sleeve (321) and near the end of the arc plate (324). The support ring a (325) is provided with the same number of sliding grooves (326) as the arc plate (324). The arc plate (324) is provided with a slider (327) that moves radially along the movable sliding sleeve (321). The slider (327) is slidably disposed in cooperation with the sliding grooves (326).

4. The anti-breakage device for the horizontal section of the directional long drilling of the base plate according to claim 3, characterized in that: The anti-breakage component (3) also includes a transmission component b disposed on the outer tube (5) and used to drive the movable sliding sleeve (321) to move; The transmission assembly b includes a support ring b (33) extended at the end of the movable sliding sleeve (321) and a fixed ring (34) adjacent to and spaced apart on one side of the support ring b (33). A screw (35) and a guide rod (36) are respectively provided on both sides of the fixed ring (34). A section of the screw (35) is connected to the support ring b (33), and a section of the guide rod (36) is slidably guided to the corresponding position on the support ring b (33).

5. The anti-breakage device for the horizontal section of the directional long drilling of the base plate according to claim 4, characterized in that: The outer end of the fixed ring (34) is provided with a transmission component c; The transmission assembly c includes a gear 1 (37) disposed on the outer wall of the outer tube (5) and a gear 2 (371) that is connected to the gear 1 (37) and disposed outside the screw (35). The inner side of the end face of the gear 2 (371) is provided with an outer ring (372) and an inner ring (373) that are coaxially sleeved. The inner wall of the outer ring (372) is provided with a plurality of wedge-shaped spaces (374) evenly distributed. A spring (375) is provided in each wedge-shaped space (374) along the tangent of the inner ring (373). A roller (376) is provided on the end of the spring (375) near the inner ring (373). The inner ring (373) is sleeved and fixed on the outer wall of the screw (35). When the outer tube (5) rotates counterclockwise under the power of the directional drilling machine, the gear one (37) and the gear two (371) cooperate to drive the gear two (371) to rotate clockwise. At this time, the roller (376) is pushed towards the narrow end of the wedge space (374) under the action of friction and the spring (375), locking the outer ring (372) and the inner ring (373), thereby driving the screw (35) passing through the inner ring (373) to rotate synchronously. When the outer tube (5) rotates clockwise, the outer ring (372) will rotate counterclockwise with the gear two (371), causing the roller (376) to be pushed towards the wide end of the wedge-shaped space (374), releasing the lock between the outer ring (372) and the inner ring (373), the outer ring (372) will rotate freely, and the inner ring (373) will not move.

6. The anti-breakage device for the horizontal section of the directional long drilling of the base plate according to claim 4, characterized in that: A telescopic cover (7) is provided on the screw (35) between the support ring a (325) and the support ring b (33). A cleaning block (8) is provided on the support ring b (33) at the end face of the support ring a (325) and at the position where the guide rod (36) passes through and slides. The cleaning block (8) is used to scrape off the sand and rock debris attached to the surface of the guide rod (36).

7. The anti-breakage device for the horizontal section of the directional long drilling of the base plate according to claim 5, characterized in that: Each structure included in the transmission assembly c is covered with a dustproof shell (9).

8. A method for preventing breakage, used in the anti-breakage device for the horizontal section of a long directional drill hole in a base plate as described in any one of claims 1-7, characterized in that, Specifically, the following steps are included: S1. Analyze the lithological characteristics between coal seam groups, establish a numerical model, and determine the reasonable arrangement of directional long boreholes and easily fractured areas based on the deformation and pressure relief and permeability enhancement characteristics at different locations between coal seam groups. S2, the directional drilling rig equipment is positioned and used in conjunction with multiple drill rods (1) to carry out directional long hole construction in the target area; S3, at the soil exit point, remove the drill bit on the corresponding drill rod (1), replace and combine the back expansion drill bit (2) and the grouting pipe assembly, continue to use the directional drilling machine, back drill multiple sequentially combined drill rods (1) from the soil exit point to the soil entry point, and enlarge the diameter of the long borehole through the back expansion drill bit (2). S4, the high-pressure grouting pump is positioned, and the inner tube (4) is used in conjunction with the connector (41) and two or more nozzles (42) evenly distributed on the connector (41) to uniformly grout and solidify the hole wall of the long borehole during the rotation of the inner tube (4); S5, for the easily broken area determined in step S1, during the drilling back of the moving drill rod (1), the anti-breakage component (3) outside the outer tube (5) is moved to the target easily broken area. At this time, the drill rod (1) is rotated in the opposite direction, and the multiple arc plates (324) are expanded outward in a uniform manner, so that the metal sleeve (31) is plastically deformed and closely attached to the hole wall of the long drill hole for support and reinforcement. S6. After the above operations are completed, breakage sampling is carried out in the easily broken areas and the results are recorded to provide data support for the next stage of directional long drilling construction and improvement of anti-breakage technology.

Images