Coal mine high-temperature goaf exploration hole in-hole limiting hole sealing device and construction method

Abstract

The application provides a coal mine high-temperature goaf exploration hole in-hole limiting hole sealing device and a construction method, and belongs to the technical field of coal mine goaf treatment. The device comprises a plugging main body, a buckle connecting structure, a double-layer staggered triangular limiting mechanism and a matched drill rod assembly. The plugging main body is conical and is integrally formed by a modified polyurethane composite material containing nano glass flake and an organic silane additive, has a temperature resistance of -20 DEG C to 190 DEG C, and has a 24h water swelling rate of 150% to 200%. The buckle connecting structure is elastically clamped with the drill rod, the triangular limiting mechanism realizes self-locking limiting, and the structures cooperatively form a double effect of mechanical limiting + material sealing. The construction method comprises assembly, lowering, limiting, separation and sealing steps, and is suitable for 75-120mm aperture drilling. The application has the advantages of high temperature resistance, corrosion resistance, reliable sealing and limiting, compact structure, convenient assembly and disassembly, high construction efficiency, low cost, and strong practicability, and is suitable for one-time plugging of goaf exploration holes in high-temperature and corrosive environments such as coalfield fire zones.

Description

Technical Field

[0001] This invention belongs to the field of coal mine goaf management technology, specifically involving a limiting and sealing device and construction method for exploration boreholes in high-temperature goaf areas of coal mines. It is applicable to the one-time sealing and limiting of exploration boreholes in goaf areas under high-temperature and corrosive environments such as coalfield fire zones, and can also be applied to sealing operations in geological caves, exploration boreholes, and other scenarios in the field of geological disaster prevention and control. Background Technology

[0002] Coalfield fire zones and goaf areas are widely distributed and located in concealed locations, requiring precise management through borehole exploration. The depth of borehole exploration in goaf areas generally reaches 30-170m, and the boreholes contain problems such as developed fissures and irregular borehole walls. At the same time, they are accompanied by corrosive media such as groundwater and mineralized liquids, as well as high-temperature environments above 190℃, which places stringent requirements on the high-temperature resistance, corrosion resistance, sealing and limiting performance of borehole sealing devices.

[0003] After the exploration borehole in the goaf is completed, temporary sealing must be carried out in a timely manner. The reliable limiting and sealing of the device are the core of the effectiveness of the treatment operation: if the limiting fails, the device is prone to displacement, causing a large amount of sealing mortar to flow into the goaf, resulting in material waste; if the sealing effect is poor, media leakage is likely to occur, leading to treatment failure. Existing sealing devices mostly use metal or ordinary rubber materials, which are prone to aging and failure in high-temperature corrosive environments, resulting in poor sealing and limiting effects; some devices have complex structures, requiring additional supporting components to adapt to boreholes of different diameters, making construction cumbersome and inefficient; moreover, traditional casing sealing devices are costly and difficult to adapt to the one-time use requirements of large-scale treatment in coalfield fire areas. Summary of the Invention

[0004] The purpose of this invention is to provide a limiting and sealing device and method for boreholes in high-temperature goaf areas of coal mines, which solves the problems of poor performance, poor sealing and limiting effect, cumbersome construction and high cost of existing sealing devices in high-temperature corrosive environments, and achieves efficient, reliable and one-time sealing of boreholes in goaf areas.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A limiting and sealing device for exploration boreholes in high-temperature goaf areas of coal mines, including a sealing body, a snap-fit ​​connection structure, a double-layer staggered triangular limiting mechanism, and a matching drill rod assembly; The sealing body is integrally molded from a water-swellable, corrosion-resistant, and high-temperature resistant composite material. The water-swellable, corrosion-resistant, and high-temperature resistant composite material is a modified polyurethane water-swellable composite material with added nano glass flake anti-corrosion filler and organosilane high-temperature resistant additive. The sealing body is a conical structure with a larger diameter at the top than at the bottom, and the diameter at the top is smaller than the borehole diameter; The snap-fit ​​connection structure is located at the center of the upper end of the sealing body and can be detachably snapped into the matching drill rod assembly. The double-layer misaligned triangular limiting mechanism is located on the side wall of the sealing body and is used to achieve self-locking and limiting between the sealing device and the borehole wall.

[0006] Preferably, the snap-fit ​​connection structure is a cylindrical protrusion integrally formed with the sealing body. The diameter of the cylindrical protrusion is smaller than the inner diameter of the matching drill rod assembly, and the upper outer wall of the cylindrical protrusion is provided with symmetrically arranged spring mounting holes.

[0007] Preferably, the double-layer staggered triangular limiting mechanism includes multiple upper triangular limiting groups and lower triangular limiting groups, the upper triangular limiting groups and the lower triangular limiting groups are axially spaced by a certain distance and arranged in a circumferentially staggered manner; each of the upper triangular limiting groups and the lower triangular limiting groups includes a triangular support block, the triangular support block is a right-angled triangle structure, and the right-angled side faces downward towards the sealing body.

[0008] Preferably, the side wall of the sealing body has an upward-opening receiving opening for each triangular support block, and the receiving opening can completely accommodate the triangular support block in the contracted state; the inner wall of the receiving opening is provided with a pin rod, and the root of the triangular support block is hinged to the pin rod, so that the triangular support block can rotate around the pin rod to contract or expand.

[0009] Preferably, the matching drill rod assembly is made of carbon steel, with symmetrical limit holes opened on its lower side wall. A spring is installed inside the spring mounting hole, and a steel ball is provided at the end of the spring. The steel ball abuts against the inner side of the limit hole, and the diameter of the steel ball is larger than the diameter of the limit hole.

[0010] Preferably, when the device is lowered, the triangular support block is squeezed by the borehole wall and rotates inward around the pin rod and retracts into the receiving opening; when the matching drill rod assembly is pulled upward, the triangular support block is rubbed by the borehole wall and rotates in the opposite direction around the pin rod and opens to clamp the borehole wall, thereby achieving self-locking and limiting.

[0011] Preferably, after the matching drill rod assembly is fitted into the cylindrical protrusion, the compression spring pops out and pushes the steel ball into the limiting hole, realizing a firm connection between the matching drill rod assembly and the sealing body; when the matching drill rod assembly is pulled upward, the inner wall of the matching drill rod assembly generates radial pressure on the steel ball, pushing the compression spring to contract, releasing the locking fit between the steel ball and the limiting hole, and realizing convenient separation of the matching drill rod assembly from the sealing body.

[0012] Another aspect of the present invention provides a method for borehole sealing in high-temperature goaf areas of coal mines using the aforementioned device, comprising the following steps: S1. Device assembly: Insert the lower end of the matching drill pipe assembly into the snap-fit ​​connection structure at the upper end of the sealing body, so that the matching drill pipe assembly and the sealing body can be detachably snap-fit ​​connected. S2. Device lowering: The sealing body is transported to the preset sealing position in the borehole by the matching drill rod assembly. During the lowering process, the double-layer staggered triangular limiting mechanism is squeezed and contracted by the borehole wall to ensure the smooth descent of the device. S3, Self-locking limit: After reaching the preset sealing position, slowly pull the matching drill rod assembly upward to make the double-layer misaligned triangular limit mechanism pop out and clamp the borehole wall, so as to realize the self-locking limit between the device and the borehole wall. S4. Drill pipe separation: Continue to pull the matching drill pipe assembly upwards to separate the matching drill pipe assembly from the sealing body, leaving the sealing body inside the borehole in one go; S5. Expansion Seal: Water is injected into the borehole, causing the water-swellable, corrosion-resistant, and high-temperature resistant composite material of the sealing body to expand upon contact with water, adhere to the borehole wall, and fill the gaps to form a sealing structure.

[0013] Preferably, in step S3, the upward pulling force of the matching drill rod assembly is gradually increased, and the friction between the borehole wall and the double-layer misaligned triangular limiting mechanism is used to achieve a self-locking limiting effect, ensuring that the sealing body does not shift.

[0014] Preferably, in step S5, the water injection pressure acts on the conical surface of the conical sealing body, further compacting the sealing body and the borehole wall to form a permanent sealing structure; the amount of water injected is sufficient to allow the sealing body to fully expand, ensuring that the gap between the sealing body and the borehole wall is filled by 100% after expansion.

[0015] Preferably, in step S2, the sealing body forms a conical guide through a conical structure, maintaining a certain gap with the borehole wall to avoid jamming or obstruction during the lowering process.

[0016] Preferably, in step S4, the drill pipe separation process does not require additional tools, and the automatic separation of the matching drill pipe assembly from the plugging body is achieved by the lifting force.

[0017] This invention addresses the complex working conditions of high temperature, corrosion, and irregular borehole walls in coalfield fire zones. Through integrated structural and material design, it solves the technical problems of poor performance, inadequate sealing and limiting effects, cumbersome construction, and high cost of existing sealing devices. Compared with existing technologies, it has the following significant advantages: 1. This invention exhibits excellent high-temperature resistance and corrosion resistance, making it suitable for complex working conditions: The sealing body is integrally molded from a modified polyurethane water-swellable composite material with added nano-glass flake anti-corrosion filler and organosilane high-temperature resistant additives. This material has a temperature resistance range of -20℃ to 190℃ and can maintain stable performance in the extreme high-temperature environment of 220℃ in coalfield fire areas, without aging or failure. At the same time, it has excellent acid and alkali corrosion resistance, and can resist the erosion of groundwater, mineralized liquid and other corrosive media in the borehole. It solves the problem of easy failure of traditional metal and ordinary rubber materials in high-temperature corrosive environments, and is fully suitable for the complex working conditions of exploration boreholes in coalfield fire areas and goaf areas.

[0018] 2. Dual protection of mechanical limiting and material sealing ensures reliable sealing effect: On the one hand, the double-layer staggered triangular limiting mechanism forms a self-locking limiting that "tightens as it is lifted" through the hinged rotation of the triangular support block and the friction of the borehole wall, effectively preventing the device from shifting or sliding down in the borehole, thus ensuring the accuracy of the sealing position from a mechanical structure perspective; on the other hand, the water-swellable, corrosion-resistant, and high-temperature resistant composite material expands by 150%-200% upon contact with water, which can 100% fill the gap between the sealing body and the borehole wall, and the conical structure and the water injection pressure work together to form a "tightens as it is pressed" sealing effect. The mechanical limiting and material sealing work together to completely prevent the sealing mortar from seeping into the goaf, ensuring the effectiveness of goaf treatment operations.

[0019] 3. Reasonable structural design and convenient and efficient construction operation: The device adopts an integrated molding design with no additional assembly parts. The snap-fit ​​connection structure and the matching drill pipe assembly achieve elastic engagement and automatic separation through spring steel balls. No additional tools are required for assembly and separation, making operation simple. The conical plugging body provides a natural guide for the device's descent, and the triangular support block can automatically retract and expand to ensure that the device is lowered without jamming. The overall construction time of a single device is ≤10 minutes, which greatly improves construction efficiency compared to traditional plugging processes and is suitable for construction operations in confined downhole spaces.

[0020] 4. Strong adaptability and wide range of applications: The device's conical structure and the adaptive design of the double-layer staggered triangular limiting mechanism can directly adapt to boreholes with different diameters of 75-120mm without the need for additional matching components, greatly improving the device's adaptability to different working conditions. This device and construction method are not only suitable for one-time sealing of exploration boreholes in high-temperature goaf areas of coalfield fire zones, but can also be widely used in sealing operations of geological caves and various engineering exploration boreholes in the field of geological disaster prevention and control. It has a wide range of applications and strong practicality.

[0021] 5. Low cost and suitable for large-scale treatment: The modified polyurethane water-swellable composite material used in the sealing body costs only about 30% of the cost of traditional metal materials. Moreover, the device is disposable and does not need to be recycled, which greatly reduces material costs. The matching drill rod assembly can be recycled and reused, further saving construction costs. At the same time, the construction process does not require professional technicians and complex equipment, and the construction labor cost is low. It is fully suitable for the batch application needs of large-scale treatment of coalfield fire areas and goaf areas, and has both economic efficiency and practicality.

[0022] 6. Compact structure and light weight, facilitating underground transportation and construction: All structures of the device are integrally formed or compactly connected with the sealing body. The overall structure is simple and lightweight, which facilitates transportation and handling in coal mines. It is especially suitable for the construction needs of deep wells with exploration depths of 30-170m in goaf areas, reducing the labor intensity of underground construction. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a three-dimensional perspective view of the present invention.

[0025] Figure 2 This is a three-dimensional solid model of the present invention.

[0026] Figure 3 This is a diagram showing the installation structure of the triangular support block of the present invention.

[0027] Figure 4 This is a diagram showing the connection structure between the snap-fit ​​connection structure and the matching drill pipe assembly of the present invention.

[0028] Figure 5 For the present invention Figure 1 Enlarged view of part A in the middle.

[0029] In the diagram: 1. Blocking body; 2. Clip-on connection structure; 3. Double-layer staggered triangular limiting mechanism; 4. Matching drill rod assembly; 5. Spring mounting hole; 6. Upper triangular limiting group; 7. Lower triangular limiting group; 8. Triangular support block; 9. Accommodating small opening; 10. Limiting hole; 11. Spring; 12. Steel ball; 13. Pin rod. Detailed Implementation The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0030] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] Example 1: See Figure 1-5 This embodiment provides a limiting and sealing device for boreholes in high-temperature goaf areas of coal mines, suitable for sealing operations of boreholes with a diameter of 75mm in high-temperature goaf areas of coal mines. To achieve reliable sealing and self-locking limiting under high-temperature and corrosive conditions, the device includes a sealing body 1, a snap-fit ​​connection structure 2, a double-layer staggered triangular limiting mechanism 3, and a matching drill rod assembly 4. To ensure the sealing performance and weather resistance of the core of the device, the sealing body 1 is integrally molded from a water-swellable, corrosion-resistant, and high-temperature resistant composite material. The water-swellable, corrosion-resistant, and high-temperature resistant composite material is a modified polymer with added nano-glass flake anti-corrosion filler and organosilane high-temperature resistant additives. The device is made of a water-swellable urethane composite material. To balance the guiding and sealing performance during device placement, the sealing body 1 is a conical structure with an upper diameter larger than its lower diameter, and the upper diameter is smaller than the borehole diameter. To enable rapid assembly and disassembly of the sealing body and drill pipe, adapting to downhole operation requirements, the snap-fit ​​connection structure 2 is located at the upper center of the sealing body 1 and can be detachably snapped into the matching drill pipe assembly 4. To prevent the device from shifting within the borehole and ensure accurate sealing positioning, the double-layer staggered triangular limiting mechanism 3 is located on the side wall of the sealing body 1 to achieve self-locking and limiting of the sealing device and the borehole wall. This structure forms the core framework of the device, with each component working collaboratively to form a complete sealing system of "connection-limiting-sealing." The integrated molding and modular design make the device compact with no redundant parts, adapting to the construction and transportation needs of confined downhole spaces.

[0034] Furthermore, to achieve elastic engagement between the snap-fit ​​connection structure and the matching drill rod assembly, simplify the connection structure, and improve assembly and disassembly efficiency, the snap-fit ​​connection structure 2 is a cylindrical protrusion integrally formed with the sealing body 1. The diameter of the cylindrical protrusion is smaller than the inner diameter of the matching drill rod assembly 4, and symmetrically arranged spring mounting holes 5 are provided on the upper outer wall of the cylindrical protrusion. This structure has no splicing gap with the sealing body, has high structural strength, and requires no assembly process. The symmetrical arrangement of the spring mounting holes ensures uniform engagement force, preventing misalignment between the drill rod and the sealing body. At the same time, the size design of the cylindrical protrusion allows the drill rod to be smoothly inserted without any jamming resistance.

[0035] Furthermore, to achieve self-locking and limiting of the device and the borehole wall, and to improve the limiting stability and avoid single-point failure, the double-layer staggered triangular limiting mechanism 3 includes multiple upper triangular limiting groups 6 and lower triangular limiting groups 7. The upper triangular limiting groups 6 and lower triangular limiting groups 7 are axially spaced by a certain distance and arranged in a circumferentially staggered manner. In order to allow the triangular support blocks to shrink under compression and open under friction, and to adapt to the irregular working conditions of the borehole wall, each of the upper triangular limiting groups 6 and lower triangular limiting groups 7 includes a triangular support block 8. The triangular support block 8 is a right-angled triangle structure, and the right-angled side faces downward of the sealing body 1. The double-layer staggered layout of the mechanism allows the limiting force to be evenly distributed in the axial and circumferential directions of the borehole. When lowered, the right-angled side of the triangular support block can quickly contract inward due to the pressure of the borehole wall. When pulled up, it can open outward and lock through the friction between the right-angled side and the borehole wall. Its right-angled triangular structure combines structural strength and movement flexibility, and can adapt to the limiting requirements of complex surfaces such as borehole wall cracks and protrusions.

[0036] Furthermore, to prevent the triangular support blocks from rubbing against the hole wall during the device's lowering process and to ensure smooth lowering, the side wall of the sealing body 1 has an upward-opening receiving opening 9 for each triangular support block 8. The receiving opening 9 can completely accommodate the retracted triangular support block 8. To enable flexible rotation of the triangular support blocks and allow them to switch between retraction and expansion, a pin 13 is provided on the inner wall of the receiving opening 9. The root of the triangular support block 8 is hinged to the pin 13, allowing the triangular support block 8 to rotate around the pin 13 to retract or expand. The receiving opening of this structure is precisely matched to the size of the triangular support block, and there are no protruding parts after retraction, completely eliminating the risk of rubbing during lowering. The hinged connection of the pin 13 ensures that the triangular support block rotates without jamming. During lowering, it can quickly retract into the receiving opening due to the pressure of the hole wall, and during lifting, it can smoothly expand due to the friction of the hole wall, completing the switching process from storage to limiting.

[0037] Furthermore, to ensure the structural strength and downhole durability of the matching drill pipe assembly, and to achieve precise engagement with the snap-fit ​​connection structure, the matching drill pipe assembly 4 is made of carbon steel, with symmetrical limit holes 10 on its lower sidewall. To provide elastic driving force to the steel ball and achieve engagement and disengagement between the steel ball and the limit hole, a spring 11 is installed inside the spring mounting hole 5, and a steel ball 12 is provided at the end of the spring 11. To prevent the steel ball from falling out of the limit hole and to ensure engagement stability, the steel ball 12 abuts against the inner side of the limit hole 10, and the diameter of the steel ball 12 is larger than the diameter of the limit hole 10. The carbon steel material allows the drill pipe to withstand the pulling and compressive forces during deep well descent. The symmetrical arrangement of the limiting hole and spring mounting hole ensures uniform force distribution during engagement. The steel ball and spring work together to form an elastic engagement structure. The working process is as follows: when the drill pipe is inserted, the spring pops out and pushes the steel ball into the limiting hole; when pulled up, the inner wall of the drill pipe squeezes the steel ball, causing the spring to contract and the steel ball to disengage from the limiting hole. No additional tools are required throughout the process, making installation and disassembly convenient.

[0038] Furthermore, to ensure the smoothness of the device's lowering process and simultaneously achieve self-locking limiting during lifting, when lowering the device, the triangular support block 8 is squeezed by the borehole wall, rotates inward around the pin rod 13, and retracts into the receiving opening 9; when lifting the matching drill rod assembly 4 upward, the triangular support block 8 is rubbed by the borehole wall, rotates in the opposite direction around the pin rod 13, and opens to clamp the borehole wall, achieving self-locking limiting. The working process of this structure is highly compatible with the construction operation steps. The retraction action during lowering and the opening action during lifting are both automatically triggered mechanically, requiring no manual intervention. Moreover, the greater the lifting force, the stronger the clamping force between the triangular support block and the borehole wall, forming a limiting effect that tightens as it is lifted. The limiting stability is strong, effectively preventing the device from shifting or sliding down within the borehole.

[0039] Furthermore, to ensure a secure connection between the matching drill rod assembly and the sealing body, and to guarantee the stability of the connection during the lowering process, after the matching drill rod assembly 4 is fitted into the cylindrical protrusion, the compression spring 11 pops out and pushes the steel ball 12 into the limiting hole 10, thus achieving a secure connection between the matching drill rod assembly 4 and the sealing body 1. To facilitate the separation of the drill rod from the sealing body, allowing the sealing body to be left in the hole at once, when the matching drill rod assembly 4 is pulled upwards, the inner wall of the matching drill rod assembly 4 generates radial pressure on the steel ball 12, pushing the compression spring 11 to contract and release the locking fit between the steel ball 12 and the limiting hole 10, thus achieving convenient separation between the matching drill rod assembly 4 and the sealing body 1. The locking and separating of this structure are both triggered by the lifting action, realizing continuous operation of installation, lifting, and separation. The working process has no complicated steps, and the assembly and separation time of a single device is within 1 minute, greatly improving construction efficiency. Moreover, the elastic cooperation between the steel ball and the spring ensures that the connection and separation actions are precise and stable, without any jamming faults.

[0040] Working principle of this invention: The limiting and sealing device for exploration holes in high-temperature goaf areas of coal mines of the present invention achieves self-locking limiting and water-swelling sealing of exploration holes in high-temperature corrosive environments through the coordinated design of material properties and mechanical structure. The core relies on the expansion characteristics of water-swelling, corrosion-resistant, and high-temperature resistant composite materials, the guiding and sealing adaptability of the conical sealing body, the mechanical self-locking principle of the double-layer staggered triangular limiting mechanism, and the elastic engagement and disengagement principle of the snap-fit ​​connection structure and the matching drill rod assembly. The various structures cooperate with each other to form a dual sealing effect of mechanical limiting and material sealing.

[0041] The sealing core of the device is a water-swellable, corrosion-resistant, and high-temperature resistant composite material. Upon contact with water, it expands by 150%-200% in volume, fully filling the gap between the sealing body and the borehole wall. Its high-temperature resistance and corrosion resistance ensure the material's performance stability under complex conditions in coalfield fire zones. The conical sealing body's structural design provides natural guidance for lowering the device and creates a tighter fit under water pressure. The double-layered staggered triangular limiting mechanism uses the hinged rotation of the triangular support blocks, utilizing the pressure and friction of the borehole wall to achieve a self-locking limit that tightens as the device is lifted, preventing displacement. The snap-fit ​​connection structure and the matching drill rod assembly achieve rapid assembly and convenient separation through the elastic engagement of spring steel balls, requiring no additional tools and adapting to the operational needs of downhole construction.

[0042] Working process of this invention: The complete working process of the device of the present invention is adapted to the construction method. Combining the structural characteristics of the device with the on-site construction process, the specific working process is as follows: Assembly and engagement: Insert the lower end of the matching drill rod assembly 4 into the snap-fit ​​connection structure 2 at the upper end of the sealing body 1. At this time, the spring 11 in the spring mounting hole 5 pops out and pushes the steel ball 12 into the limiting hole 10 of the matching drill rod assembly 4. The steel ball 12 abuts against the inner side of the limiting hole 10 to form a tight fit, thus completing the firm connection between the sealing body 1 and the matching drill rod assembly 4. No additional tools are required during the assembly process, and the operation is convenient.

[0043] Lowering Guide: The sealing body 1 is slowly transported to the preset sealing position in the borehole through the matching drill rod assembly 4. During the lowering process, the conical structure of the sealing body 1 forms a conical guide, maintaining a reasonable gap with the borehole wall to avoid jamming. At the same time, the triangular support block 8 of the double-layer staggered triangular limiting mechanism 3 is subjected to the squeezing force of the borehole wall, rotates inward around the pin rod 13 and completely retracts into the receiving small opening 9, ensuring that the entire device descends smoothly without jamming.

[0044] Self-locking limit: When the sealing body 1 reaches the preset sealing position, the matching drill rod assembly 4 is slowly pulled upward. Under the action of its own weight and the friction of the hole wall, the sealing body 1 moves downward relative to the matching drill rod assembly 4. Under the action of the friction of the hole wall, the triangular support block 8 rotates in the opposite direction around the pin rod 13 and opens from the receiving small opening 9, gradually locking into the crack or irregular protrusion of the borehole wall. Continue to gradually increase the pulling force, and the clamping force between the triangular support block 8 and the hole wall increases synchronously, realizing the self-locking limit effect of "the more you pull, the tighter it gets", ensuring that the sealing body 1 does not shift or slide down in the borehole.

[0045] Elastic separation: After the limit is completed, continue to pull the matching drill rod assembly 4 upward. The inner wall of the matching drill rod assembly 4 generates radial extrusion force on the steel ball 12. This pressure pushes the spring 11 to contract into the spring mounting hole 5, and the steel ball 12 is released from the limit hole 10, releasing the clamping fit between the steel ball 12 and the limit hole 10, thus realizing the automatic separation of the matching drill rod assembly 4 from the sealing body 1. After separation, the sealing body 1 is left in the borehole at once, and the matching drill rod assembly 4 can be recycled and reused.

[0046] Water-swellable sealing: Clean water is injected into the borehole, with the amount of water sufficient to fully expand the sealing body 1. The water injection pressure acts on the conical surface of the conical sealing body 1, causing the sealing body 1 to initially compact with the borehole wall. The water-swellable, corrosion-resistant, and high-temperature resistant composite material of the sealing body 1 begins to expand in volume after contact with water, reaching an expansion rate of 150%-200% within 24 hours. It gradually adheres to the borehole wall and fills all gaps between the borehole wall and the sealing body 1, achieving a gap filling rate of 100%. At the same time, the expanded material and the water injection pressure work together to form a permanent sealing structure between the sealing body 1 and the borehole wall that becomes tighter with pressure, effectively preventing the sealing mortar from entering the goaf and achieving reliable sealing of the borehole.

[0047] Example 2: Another aspect of the present invention provides a method for borehole sealing in high-temperature goaf areas of coal mines using the aforementioned device, comprising the following steps: S1. Device assembly: Insert the lower end of the matching drill rod assembly 4 into the snap-fit ​​connection structure 2 at the upper end of the sealing body 1, so that the matching drill rod assembly 4 and the sealing body 1 can be detachably snap-fit ​​connected. S2. Device lowering: The sealing body 1 is transported to the preset sealing position in the borehole by the matching drill rod assembly 4. During the lowering process, the double-layer staggered triangular limiting mechanism 3 is squeezed and contracted by the borehole wall to ensure the smooth descent of the device. S3, Self-locking limit: After reaching the preset sealing position, slowly pull the matching drill rod assembly 4 upward to make the double-layer misaligned triangular limit mechanism 3 pop out and clamp the borehole wall, so as to realize the self-locking limit between the device and the borehole wall. S4. Drill pipe separation: Continue to pull the matching drill pipe assembly 4 upward to separate the matching drill pipe assembly 4 from the sealing body 1, leaving the sealing body 1 inside the borehole in one go; S5. Expansion sealing: Water is injected into the borehole, causing the water-swellable, corrosion-resistant, and high-temperature resistant composite material of the sealing body 1 to expand upon contact with water, adhere to the borehole wall and fill the gaps, forming a sealing structure.

[0048] Furthermore, in step S3, the upward pulling force of the matching drill rod assembly 4 is gradually increased, and the friction between the borehole wall and the double-layer misaligned triangular limiting mechanism 3 is used to achieve a self-locking limiting effect, ensuring that the sealing body 1 does not shift.

[0049] Furthermore, in step S5, the water injection pressure acts on the conical surface of the conical sealing body 1, further compacting the sealing body 1 with the borehole wall to form a permanent sealing structure; the amount of water injected is based on the need for the sealing body 1 to fully expand, ensuring that the gap filling rate between the sealing body 1 and the borehole wall is 100% after expansion.

[0050] Furthermore, in step S2, the sealing body 1 forms a conical guide through a conical structure, maintaining a certain gap with the borehole wall to avoid jamming or obstruction during the lowering process.

[0051] Furthermore, in step S4, the drill pipe separation process does not require additional tools; the automatic separation of the matching drill pipe assembly 4 from the plugging body 1 is achieved through a lifting force.

[0052] Example 3: This embodiment provides a limiting and sealing device for boreholes in high-temperature goaf areas of coal mines, suitable for sealing operations of boreholes with a diameter of 90mm in high-temperature goaf areas of coal mines. To achieve both sealing and limiting effects under high-temperature corrosion conditions in medium-diameter boreholes, the device includes a sealing body 1, a snap-fit ​​connection structure 2, a double-layer staggered triangular limiting mechanism 3, and a matching drill rod assembly 4. To ensure the sealing performance and weather resistance of the core components of the device, the sealing body 1 is integrally molded from a water-swellable, corrosion-resistant, and high-temperature resistant composite material. The water-swellable, corrosion-resistant, and high-temperature resistant composite material is a modified polyurethane water-swellable composite material with added nano-glass flake anti-corrosion filler and organosilane high-temperature resistant additives, with a temperature resistance range of -20℃ to 190℃. The device expands by 180% upon contact with water within 24 hours. To balance the guiding and sealing performance of the device during lowering, the sealing body 1 is a conical structure with an upper diameter larger than the lower diameter, a length of 250mm, an upper diameter of 85mm, a lower diameter of 80mm, and an upper diameter smaller than the borehole diameter. To enable rapid assembly and disassembly of the sealing body and drill pipe, adapting to downhole operation requirements, the snap-fit ​​connection structure 2 is located at the upper center of the sealing body 1 and can be detachably snapped into place with the matching drill pipe assembly 4. To prevent the device from shifting within the borehole and ensure the accuracy of the sealing position, the double-layer misaligned triangular limiting mechanism 3 is located on the side wall of the sealing body 1 to achieve self-locking and limiting of the sealing device and the borehole wall. This structure forms the core framework of the device. Each component works together to form a complete sealing system of "connection-limiting-sealing". The integrated molding and modular design make the device compact and free of redundant parts, which can meet the construction and transportation needs of the narrow space downhole. The 250mm length design balances the construction convenience of medium-diameter drilling and the sealing area, avoiding the problems of jamming due to excessive length and insufficient sealing due to excessive short length.

[0053] Furthermore, to achieve elastic engagement between the snap-fit ​​connection structure and the matching drill rod assembly, simplify the connection structure, and improve assembly and disassembly efficiency, the snap-fit ​​connection structure 2 is a cylindrical protrusion integrally formed with the sealing body 1. The cylindrical protrusion has a diameter of 30mm, which is 8mm smaller than the inner diameter of the matching drill rod assembly 4. The upper outer wall of the cylindrical protrusion has symmetrically arranged spring mounting holes 5, with a depth of 4mm. This structure has no splicing gap with the sealing body, has high structural strength, and requires no assembly process. The symmetrical arrangement of the spring mounting holes ensures uniform engagement force, preventing misalignment between the drill rod and the sealing body. At the same time, the size design of the cylindrical protrusion is suitable for conventional drill rods with a 90mm hole diameter, allowing the drill rod to be smoothly inserted without jamming resistance, thus improving the assembly and disassembly efficiency of medium-diameter drilling.

[0054] Furthermore, to achieve self-locking and limiting of the device and the borehole wall, and to improve the limiting stability and avoid single-point failure, the double-layer staggered triangular limiting mechanism 3 includes multiple upper triangular limiting groups 6 and lower triangular limiting groups 7. The axial distance between the upper triangular limiting groups 6 and the lower triangular limiting groups 7 is 60mm, and they are arranged with a circumferential stagger of 60°. In order to allow the triangular support blocks to shrink under compression and open under friction, and to adapt to the irregular working conditions of the borehole wall, each of the upper triangular limiting groups 6 and the lower triangular limiting groups 7 includes 3 triangular support blocks 8. The triangular support blocks 8 are right-angled triangles with a right-angled side length of 6mm and a thickness of 3.5mm, and the right-angled side faces downwards towards the sealing body 1. The double-layer staggered layout of this mechanism allows the limiting force to be evenly distributed in the axial and circumferential directions of the borehole. The 60mm axial spacing is suitable for the contact force of the borehole wall in medium-diameter boreholes. When lowering, the right-angled side of the triangular support block can quickly retract inward due to the pressure of the borehole wall. When lifting, it can open outward and lock through the friction between the right-angled side and the borehole wall. Its right-angled triangular structure combines structural strength and movement flexibility, which can adapt to the working conditions of medium-diameter boreholes with developed cracks and irregularities, and improve the stability of the limiting.

[0055] Furthermore, to prevent the triangular support blocks from rubbing against the hole wall during the lowering of the device and to ensure smooth lowering, the side wall of the sealing body 1 is provided with an upward-opening receiving opening 9 for each triangular support block 8. The receiving opening 9 is 8mm deep and can completely accommodate the triangular support block 8 in its retracted state. To enable the triangular support blocks to rotate flexibly and switch between retracting and opening actions, a pin rod 13 is provided on the inner wall of the receiving opening 9. The root of the triangular support block 8 is hinged to the pin rod 13, so that the triangular support block 8 can rotate around the pin rod 13 to retract or open. The structure's accommodating opening is precisely matched to the size of the triangular support block. After retraction, there are no protruding parts, completely eliminating the risk of scratches during lowering. The hinged connection of the pin rod allows the triangular support block to rotate without jamming. When lowering, it can quickly retract into the accommodating opening due to the pressure of the hole wall, and when lifting, it can smoothly open due to the friction of the hole wall, completing the work process switching from storage to limiting. It is suitable for lowering and limiting conditions in medium-diameter drilling.

[0056] Furthermore, to ensure the structural strength and downhole durability of the matching drill pipe assembly, and to achieve precise engagement with the snap-fit ​​connection structure, the matching drill pipe assembly 4 is made of carbon steel, with symmetrically opened limiting holes 10 on its lower sidewall, each limiting hole having a diameter of 5mm. To provide elastic driving force to the steel ball and achieve engagement and disengagement between the steel ball and the limiting hole, a spring 11 is positioned and installed inside the spring mounting hole 5, with a spring constant of 10N / mm. A steel ball 12 with a diameter of 6mm is provided at the end of the spring 11. To prevent the steel ball from coming out of the limiting hole and to ensure engagement stability, the steel ball 12 abuts against the inner side of the limiting hole 10, and the diameter of the steel ball 12 is larger than the diameter of the limiting hole 10. The carbon steel material allows the drill rod to withstand the pulling and compressive forces during the lowering of medium-diameter deep holes. The symmetrical arrangement of the limiting hole and the spring mounting hole ensures uniform force distribution during engagement. The cooperation between the steel ball and the spring forms an elastic engagement structure. The working process is as follows: when the drill rod is inserted, the spring pops out and pushes the steel ball into the limiting hole. When pulled up, the inner wall of the drill rod squeezes the steel ball, causing the spring to contract and the steel ball to disengage from the limiting hole. No additional tools are required throughout the process, making installation and disassembly convenient. It is also suitable for the construction operation force of drilling 90mm diameter holes.

[0057] Furthermore, to ensure the smoothness of the device's lowering process and simultaneously achieve self-locking limiting during lifting, when lowering the device, the triangular support block 8 is squeezed by the borehole wall, rotates inward around the pin rod 13, and retracts into the receiving opening 9; when lifting the matching drill rod assembly 4 upward, the triangular support block 8 is rubbed by the borehole wall, rotates in the opposite direction around the pin rod 13, and opens to clamp the borehole wall, achieving self-locking limiting. The working process of this structure is highly compatible with the construction operation steps. The retraction action during lowering and the opening action during lifting are both automatically triggered mechanically, requiring no manual intervention. Moreover, the greater the lifting force, the stronger the clamping force between the triangular support block and the borehole wall, forming a limiting effect that tightens as it is lifted. The limiting stability is strong, effectively preventing the device from shifting or sliding down in a 90mm medium-diameter borehole, thus meeting the limiting requirements of medium-diameter boreholes.

[0058] Furthermore, to ensure a secure connection between the drill pipe assembly and the sealing body and to guarantee connection stability during the device lowering process, after the drill pipe assembly 4 is fitted into the cylindrical protrusion, the compression spring 11 pops out and pushes the steel ball 12 into the limiting hole 10, thus achieving a secure connection between the drill pipe assembly 4 and the sealing body 1. To facilitate the separation of the drill pipe from the sealing body, allowing the sealing body to be left in the hole at once, when the drill pipe assembly 4 is pulled upwards, the inner wall of the drill pipe assembly 4 generates radial pressure on the steel ball 12, pushing the compression spring 11 to contract and release the locking fit between the steel ball 12 and the limiting hole 10, thus achieving convenient separation between the drill pipe assembly 4 and the sealing body 1. The locking and separating of this structure are both triggered by the lifting action, realizing continuous operation of installation, lifting, and separation. Its working process has no complicated steps, and the assembly and separation time of a single device is within 1 minute, greatly improving construction efficiency. Moreover, the elastic cooperation between the steel ball and the spring ensures that the connection and separation actions are precise and stable, without jamming failures, and is suitable for the rapid construction needs of medium-diameter downhole drilling.

[0059] The device in this embodiment was tested in the Zhongcao fire zone of the Rujigou Dafeng fire area in Helan Mountain, Ningxia. It was lowered to the preset sealing position at 80m without any obstruction. It worked stably in the extreme borehole temperature environment of 220℃. After the drill rod was pulled up, the limiting position was firm and there was no displacement. After water was injected into the hole, the sealing body had an expansion rate of 180% in 24 hours. It was fully attached to the borehole wall without mortar leakage. The installation time of a single set is ≤10 minutes, which fully meets the requirements for sealing exploratory boreholes in 90mm diameter goaf areas.

[0060] Example 4: This embodiment provides a limiting and sealing device for boreholes in high-temperature goaf areas of coal mines, suitable for sealing operations of boreholes with a diameter of 120mm in high-temperature goaf areas of coal mines. To achieve a firm seal and reliable limiting under high-temperature corrosion conditions in large-diameter boreholes, the device includes a sealing body 1, a snap-fit ​​connection structure 2, a double-layer staggered triangular limiting mechanism 3, and a matching drill rod assembly 4. To ensure the sealing performance and weather resistance of the core components of the device, the sealing body 1 is integrally molded from a water-swellable, corrosion-resistant, and high-temperature resistant composite material. The water-swellable, corrosion-resistant, and high-temperature resistant composite material is a modified polyurethane water-swellable composite material with added nano-glass flake anti-corrosion filler and organosilane high-temperature resistant additives, with a temperature resistance range of -20℃ to 190℃. The device expands by 200% after 4 hours when exposed to water. To balance the guiding and sealing performance of the device during lowering, the sealing body 1 is a conical structure with a larger diameter at the top than at the bottom, 280mm in length, 115mm at the top, and 110mm at the bottom, with the top diameter being smaller than the borehole diameter. To enable rapid assembly and disassembly of the sealing body and drill pipe, adapting to downhole operation requirements, the snap-fit ​​connection structure 2 is located at the center of the upper end of the sealing body 1 and can be detachably snapped into place with the matching drill pipe assembly 4. To prevent the device from shifting within the borehole and ensure the accuracy of the sealing position, the double-layer staggered triangular limiting mechanism 3 is located on the side wall of the sealing body 1 to achieve self-locking and limiting of the sealing device and the borehole wall. This structure forms the core framework of the device, with each component working together to form a complete sealing system of "connection-limiting-sealing". The integrated molding and modular design make the device compact with no redundant parts, adapting to the construction and transportation needs of the narrow space downhole. The 280mm length design increases the sealing contact area of ​​large-diameter boreholes, and the 200% high expansion rate ensures the gap filling effect of large-diameter boreholes.

[0061] Furthermore, to achieve elastic engagement between the snap-fit ​​connection structure and the matching drill rod assembly, simplify the connection structure, and improve assembly and disassembly efficiency, the snap-fit ​​connection structure 2 is a cylindrical protrusion integrally formed with the sealing body 1. The diameter of the cylindrical protrusion is 35mm, which is 7mm smaller than the inner diameter of the matching drill rod assembly 4. The upper outer wall of the cylindrical protrusion has symmetrically arranged spring mounting holes 5, with a depth of 5mm. This structure has no splicing gap with the sealing body, has high structural strength, and requires no assembly process. The symmetrical arrangement of the spring mounting holes ensures uniform engagement force, preventing misalignment between the drill rod and the sealing body. At the same time, the size design of the cylindrical protrusion is adapted to the 120mm diameter matching large-diameter drill rod, allowing the drill rod to be smoothly inserted without jamming resistance. The 5mm depth of the spring mounting holes improves the engagement stability with the large-diameter drill rod.

[0062] Furthermore, to achieve self-locking and limiting of the device and the borehole wall, and to improve the limiting stability and avoid single-point failure, the double-layer staggered triangular limiting mechanism 3 includes multiple upper triangular limiting groups 6 and lower triangular limiting groups 7. The axial distance between the upper triangular limiting groups 6 and the lower triangular limiting groups 7 is 70mm, and they are arranged with a circumferential stagger of 60°. In order to allow the triangular support blocks to shrink under compression and open under friction, and to adapt to the irregular working conditions of the borehole wall, each of the upper triangular limiting groups 6 and the lower triangular limiting groups 7 includes 3 triangular support blocks 8. The triangular support blocks 8 are right-angled triangles with a right-angled side length of 7mm and a thickness of 4mm, and the right-angled side faces downwards towards the sealing body 1. The double-layer staggered layout of this mechanism allows the limiting force to be evenly distributed in the axial and circumferential directions of the borehole. The 70mm axial spacing and 4mm thickness of the triangular support block enhance the strength of the limiting structure for large-diameter boreholes. When lowered, the right-angled side of the triangular support block can quickly contract inward due to the pressure of the borehole wall. When pulled up, it opens outward and locks in place through the friction between the right-angled side and the borehole wall. Its right-angled triangular structure combines structural strength and movement flexibility, which can adapt to the large contact area requirements of the borehole wall of large-diameter boreholes, conform to complex surfaces such as borehole wall cracks and protrusions, and improve the limiting stability.

[0063] Furthermore, to prevent the triangular support blocks from rubbing against the hole wall during the lowering of the device and to ensure smooth lowering, the side wall of the sealing body 1 is provided with an upward-opening receiving opening 9 for each triangular support block 8. The receiving opening 9 is 9mm deep and can completely accommodate the triangular support block 8 in its retracted state. To enable the triangular support blocks to rotate flexibly and switch between retracting and opening actions, a pin rod 13 is provided on the inner wall of the receiving opening 9. The root of the triangular support block 8 is hinged to the pin rod 13, so that the triangular support block 8 can rotate around the pin rod 13 to retract or open. The structure's accommodating opening is precisely matched to the size of the triangular support block. After retraction, there are no protruding parts, completely eliminating the risk of scratches during lowering. The hinged connection of the pin rod allows the triangular support block to rotate without jamming. When lowering, it can quickly retract into the accommodating opening due to the pressure of the hole wall, and when lifting, it can smoothly open due to the friction of the hole wall, completing the work process switching from storage to limiting. The 9mm depth of the accommodating opening is adapted to the thickened triangular support block, ensuring the lowering and limiting conditions of large-diameter drilling.

[0064] Furthermore, to ensure the structural strength and downhole durability of the matching drill pipe assembly, and to achieve precise engagement with the snap-fit ​​connection structure, the matching drill pipe assembly 4 is made of carbon steel, with symmetrically opened limiting holes 10 on its lower sidewall, each limiting hole 10 having a diameter of 6mm. To provide elastic driving force to the steel ball and achieve engagement and disengagement between the steel ball and the limiting hole, a spring 11 is positioned and installed inside the spring mounting hole 5, with a spring constant of 12N / mm. A steel ball 12 with a diameter of 7mm is provided at the end of the spring 11. To prevent the steel ball from coming out of the limiting hole and to ensure engagement stability, the steel ball 12 abuts against the inner side of the limiting hole 10, and the diameter of the steel ball 12 is larger than the diameter of the limiting hole 10. The carbon steel material allows the drill rod to withstand the pulling and compressive forces during the lowering of large-diameter, ultra-deep holes. The symmetrical arrangement of the limiting hole and spring mounting hole ensures uniform force during engagement. The high-efficiency spring with a spring coefficient of 12N / mm and the 7mm steel ball enhance the elastic driving force and engagement stability when connected to the large-diameter drill rod. The working process is as follows: when the drill rod is inserted, the spring pops out and pushes the steel ball into the limiting hole; when pulled up, the inner wall of the drill rod squeezes the steel ball, causing the spring to contract and the steel ball to disengage from the limiting hole. No additional tools are required throughout the process, making it easy to install and disassemble, and suitable for the construction operation requirements of large-diameter drilling.

[0065] Furthermore, to ensure the smoothness of the device's lowering process and simultaneously achieve self-locking limiting during lifting, when lowering the device, the triangular support block 8 is squeezed by the borehole wall, rotates inward around the pin rod 13, and retracts into the receiving opening 9; when lifting the matching drill rod assembly 4 upward, the triangular support block 8 is rubbed by the borehole wall, rotates in the opposite direction around the pin rod 13, and opens to clamp the borehole wall, achieving self-locking limiting. The working process of this structure is highly compatible with the construction operation steps. The retraction action during lowering and the opening action during lifting are both automatically triggered mechanically, requiring no manual intervention. Moreover, the greater the lifting force, the stronger the clamping force between the triangular support block and the borehole wall, forming a limiting effect that tightens as it is lifted. The limiting stability is strong, and the thickened triangular support block can withstand the limiting force of large-diameter boreholes, effectively preventing the device from shifting or sliding down within a 120mm large-diameter borehole.

[0066] Furthermore, to ensure a secure connection between the matching drill rod assembly and the sealing body and to guarantee the stability of the connection during the lowering process of the device, after the matching drill rod assembly 4 is fitted into the cylindrical protrusion, the compression spring 11 pops out and pushes the steel ball 12 into the limiting hole 10, thereby achieving a secure connection between the matching drill rod assembly 4 and the sealing body 1. To facilitate the separation of the drill rod from the sealing body and allow the sealing body to be left in the hole at once, when the matching drill rod assembly 4 is pulled upward, the inner wall of the matching drill rod assembly 4 generates radial pressure on the steel ball 12, pushing the compression spring 11 to contract and release the locking fit between the steel ball 12 and the limiting hole 10, thereby achieving a convenient separation between the matching drill rod assembly 4 and the sealing body 1. The engagement and disengagement of this structure are triggered by a lifting action, enabling continuous operation of loading, lifting, and disengagement. The working process is free of complicated steps, and the assembly and disengagement time of a single unit is within 1 minute, which greatly improves construction efficiency. Furthermore, the elastic combination of high stiffness coefficient springs and large-diameter steel balls ensures precise and stable connection and disengagement without jamming, making it suitable for the rapid construction needs of large-diameter boreholes in downholes.

[0067] The device in this embodiment was tested on-site at the Rujigou Coal Mine in Ningxia. It was lowered to the preset sealing position at 170m without any obstruction. It worked stably in an extreme borehole temperature environment of 220℃. The sealing body showed no signs of aging or corrosion. After the drill rod was pulled up, the limiting position was firm and there was no displacement. After water was injected into the borehole, the sealing body expanded by 200% in 24 hours. It fully adhered to the borehole wall without any slurry leakage. The installation time for a single set was 10 minutes, which fully meets the requirements for sealing ultra-deep boreholes in goaf areas with a borehole diameter of 120mm.

[0068] Although the preferred embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many specific modifications under the guidance of the present invention without departing from the spirit of the invention and the scope of protection of the claims, and these modifications all fall within the scope of protection of the present invention.

Claims

1. A limiting and sealing device for exploration boreholes in high-temperature goaf areas of coal mines, characterized in that, It includes a sealing body (1), a snap-fit ​​connection structure (2), a double-layer misaligned triangular limiting mechanism (3), and a matching drill rod assembly (4). The sealing body (1) is integrally molded with a water-swellable, corrosion-resistant, and high-temperature resistant composite material. The water-swellable, corrosion-resistant, and high-temperature resistant composite material is a modified polyurethane water-swellable composite material with added nano glass flake anti-corrosion filler and organosilane high-temperature resistant additive. The sealing body (1) is a conical structure with an upper diameter greater than the lower diameter, and the upper diameter is smaller than the borehole diameter; The snap-fit ​​connection structure (2) is located at the center of the upper end of the sealing body (1) and is detachably snap-fitted with the matching drill rod assembly (4); The double-layer misaligned triangular limiting mechanism (3) is located on the side wall of the sealing body (1) and is used to achieve self-locking and limiting of the sealing device and the borehole wall.

2. The limiting and sealing device for exploration boreholes in high-temperature goaf areas of coal mines according to claim 1, characterized in that, The snap-fit ​​connection structure (2) is a cylindrical protrusion integrally formed with the sealing body (1). The diameter of the cylindrical protrusion is smaller than the inner diameter of the matching drill rod assembly (4). Symmetrically arranged spring mounting holes (5) are provided on the upper outer wall of the cylindrical protrusion.

3. The limiting and sealing device for exploration boreholes in high-temperature goaf areas of coal mines according to claim 1, characterized in that, The double-layer staggered triangular limiting mechanism (3) includes multiple upper triangular limiting groups (6) and lower triangular limiting groups (7). The upper triangular limiting groups (6) and the lower triangular limiting groups (7) are axially spaced by a certain distance and arranged in a staggered manner in the circumferential direction. Each upper triangular limiting group (6) and lower triangular limiting group (7) includes a triangular support block (8). The triangular support block (8) is a right-angled triangle structure, and the right-angled side faces downwards towards the sealing body (1).

4. The limiting and sealing device for exploration boreholes in high-temperature goaf areas of coal mines according to claim 3, characterized in that, The sealing body (1) has an upward-opening receiving opening (9) on the side wall corresponding to each triangular support block (8). The receiving opening (9) can completely accommodate the triangular support block (8) in a contracted state. The inner wall of the receiving opening (9) is provided with a pin (13). The root of the triangular support block (8) is hinged to the pin (13), so that the triangular support block (8) can rotate around the pin (13) to contract or open.

5. The borehole limiting and sealing device for high-temperature goaf areas in coal mines according to claim 2, characterized in that, The matching drill rod assembly (4) is made of carbon steel, and symmetrical limit holes (10) are opened on the lower side wall. A spring (11) is installed inside the spring mounting hole (5). A steel ball (12) is provided at the end of the spring (11). The steel ball (12) abuts against the inner side of the limit hole (10). The diameter of the steel ball (12) is larger than the diameter of the limit hole (10).

6. The borehole limiting and sealing device for high-temperature goaf areas in coal mines according to claim 4, characterized in that, When the device is lowered, the triangular support block (8) is squeezed by the borehole wall and rotates inward around the pin rod (13) and retracts into the receiving opening (9); when the matching drill rod assembly (4) is pulled upward, the triangular support block (8) is rubbed by the borehole wall and rotates in the opposite direction around the pin rod (13) and opens to clamp the borehole wall, thus achieving self-locking and limiting.

7. The borehole limiting and sealing device for high-temperature goaf areas in coal mines according to claim 5, characterized in that, After the matching drill rod assembly (4) is fitted into the cylindrical protrusion, the compression spring (11) pops out and pushes the steel ball (12) into the limiting hole (10), thus realizing a firm connection between the matching drill rod assembly (4) and the sealing body (1); when the matching drill rod assembly (4) is pulled upward, the inner wall of the matching drill rod assembly (4) generates radial pressure on the steel ball (12), which pushes the compression spring (11) to contract, releasing the tight fit between the steel ball (12) and the limiting hole (10), thus realizing the convenient separation of the matching drill rod assembly (4) and the sealing body (1).

8. A method for borehole sealing in high-temperature goaf areas of coal mines using the device described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Assembly of the device: Insert the lower end of the matching drill rod assembly (4) into the snap-fit ​​connection structure (2) at the upper end of the plugging body (1) so that the matching drill rod assembly (4) and the plugging body (1) can be detachably snap-fit ​​connected. S2, Device lowering: The sealing body (1) is transported to the preset sealing position in the borehole through the matching drill rod assembly (4). During the lowering process, the double-layer staggered triangular limiting mechanism (3) is squeezed and contracted by the borehole wall to ensure the smooth descent of the device. S3, self-locking limit: After reaching the preset sealing position, slowly pull up the matching drill rod assembly (4) to make the double-layer misaligned triangular limit mechanism (3) pop out and clamp the borehole wall, so as to realize the self-locking limit between the device and the borehole wall. S4. Drill rod separation: Continue to pull the matching drill rod assembly (4) upward to separate the matching drill rod assembly (4) from the sealing body (1), and leave the sealing body (1) in the borehole at once; S5. Expansion sealing: Water is injected into the borehole, causing the water-swellable, corrosion-resistant, and high-temperature resistant composite material of the sealing body (1) to expand upon contact with water, adhere to the borehole wall and fill the gap, forming a sealing structure.

9. The method for limiting and sealing boreholes in high-temperature goaf areas of coal mines according to claim 8, characterized in that, In step S3, the upward pulling force of the matching drill rod assembly (4) gradually increases, and the friction between the borehole wall and the double-layer misaligned triangular limiting mechanism (3) is used to achieve the self-locking limiting effect, ensuring that the sealing body (1) does not shift.

10. The method for limiting and sealing boreholes in high-temperature goaf areas of coal mines according to claim 8, characterized in that, In step S5, the water injection pressure acts on the conical surface of the conical sealing body (1), further compacting the sealing body (1) with the borehole wall to form a permanent sealing structure; the amount of water injected is sufficient to allow the sealing body (1) to fully expand, ensuring that the gap between the sealing body (1) and the borehole wall is filled by 100% after expansion; In step S2, the sealing body (1) forms a cone-shaped guide through a cone-shaped structure, maintaining a certain gap with the borehole wall to avoid jamming or obstruction during the lowering process; In step S4, the drill pipe separation process does not require additional tools. The automatic separation of the matching drill pipe assembly (4) and the plugging body (1) is achieved by the lifting force.

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