A core sampling device for geological exploration based on a core drill bit

Abstract

The present application relates to the field of core sampling, and particularly relates to a geological exploration core sampling device based on a core drill bit, which comprises an outer pipe, a liftable drill rod coaxially arranged in the inner part of the outer pipe, a sampling drill bit coaxially and fixedly arranged at the bottom end of the drill rod, a liftable inner pipe coaxially arranged in the inner part of the drill rod, a liftable sampling pipe coaxially arranged in the inner part of the inner pipe, a pre-cutting unit and a cutting unit coaxially arranged and matched with the inner pipe and the sampling pipe arranged at the lower part of the drill rod, and the pre-cutting unit is arranged coaxially below the cutting unit; through the cooperative matching of the multi-stage coaxial liftable assembly, the target core can be first annularly pre-cut, and then a controllable axial force is applied to realize neat fracture, so that the end face damage, block dropping or structure disturbance caused by forced pulling or ground knocking in the traditional coring process is effectively avoided, and the core sampling rate and the fidelity of the original geological information are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of core sampling, specifically a geological exploration core sampling device based on a core drill bit. Background Technology

[0002] In geological exploration drilling operations, obtaining complete, clearly defined, and undisturbed core samples is fundamental to accurately identifying lithology, structural characteristics, and mineral occurrence. However, existing wireline coring devices generally lack effective control over the core fracturing process. After drilling and coring, they typically rely on the impact force generated by mechanical locking with spring clips and the overall lifting of the drill string, or supplemented by manual hammering on the ground, to break the core from the root. This crude truncation method easily causes core face crushing, edge spalling, and internal fracture propagation. Especially in weak, fractured, shale, and coal seams, the integrity of the core is severely compromised, leading to decreased recovery rates, distorted logging, and even loss of scientific and engineering evaluation value. Furthermore, traditional methods struggle to accurately extract specific target strata, and non-target interlayers easily contaminate the sample, affecting analytical accuracy. Although some improved solutions attempt to introduce pre-cut structures, these are often complex, require additional power, or are incompatible with standard wireline coring processes, making efficient and reliable application in actual drilling operations difficult.

[0003] Patent application number 202121153447.4 discloses a drilling pressure-maintaining sealed coring tool, including an upper connector, a conversion connector threadedly connected to the lower part of the upper connector, a drill bit threadedly and sealed to the lower end of the outer cylinder of the upper connector, a rotating shaft connected to the lower part of the conversion connector via a bearing, an upper bypass hole on the conversion connector, a lower bypass hole at the lower part of the drill bit, a sealed liquid chamber tube fixedly connected to the lower end of the rotating shaft, a pin valve provided on the lower end face of the sealed liquid chamber tube, and a pressure-maintaining chamber tube threadedly and sealed to the lower end of the sealed liquid chamber tube. The pressure-holding chamber tube contains a core sampling tube, and the outer side of the core sampling tube is equipped with a slider. The outer circle formed by the sliders is connected to the inner hole of the pressure-holding chamber tube with clearance fit. The bottom of the pressure-holding chamber tube is equipped with a flap valve. Due to the setting of an elastic diaphragm, the original air in the gas storage chamber is isolated from the gas released from the core. The gas in the diaphragm is taken out through the valve for analysis, measurement and testing, which ensures that the gas components in the core do not come into contact with the outside world, thus improving the sampling quality. The bearing part is equipped with a sealed pressure cap and dustproof cotton to prevent bearing corrosion.

[0004] Patent application number 202422785218.4 discloses a core sampling segmentation device, including a drive vehicle. A fixing ring is fixedly connected to the middle of the left side of the drive vehicle. Evenly distributed mounting feet are fixedly connected to the inner side of the fixing ring. A first limiting frame is rotatably connected to the left side of the mounting feet. A left-right opposing connecting rod is rotatably connected to the bottom of the first limiting frame. A second limiting frame is rotatably connected to the bottom of the connecting rod. A connecting plate is rotatably connected to the bottom of the second limiting frame. By damping the drill pipe, core damage can be effectively reduced, especially in brittle rocks, ensuring sample integrity. At the same time, damping helps improve segmentation accuracy, reduces the interference of drill pipe vibration on the core, and ensures more accurate sampling. It can also improve operational stability, reduce the risk of jamming and failure, reduce equipment wear, extend service life, and reduce maintenance costs.

[0005] However, the following problems still exist in practical applications, specifically:

[0006] 1. Lack of multi-level coaxial lifting structure: Both existing technologies only use a single-layer core tube or external clamping device, without setting up multi-level nested components such as inner tube and sampling tube, which makes it impossible to realize the relative lifting and coordinated movement between tubes.

[0007] 2. No pre-cutting function: Neither of the two patents is equipped with a ring-shaped pre-cutting mechanism, which cannot pre-cut a neat guide groove before the rock core fractures, resulting in an uncontrollable fracture process.

[0008] 3. Lack of a controllable axial truncation mechanism: Core fracture still relies on traditional lifting or ground impact, which cannot apply a stable and precise axial force, easily causing end face damage, chipping, or structural disturbance.

[0009] 4. Inability to guarantee the integrity of the core end face: Due to the lack of a "pre-cut + controlled tensile breaking" closed loop, especially in soft and fractured strata, the quality of the core end face is poor, which affects geological logging and experimental analysis.

[0010] Therefore, overcoming the aforementioned technical problems and defects has become a key issue that needs to be addressed. Summary of the Invention

[0011] The purpose of this invention is to overcome the defects described in the background art, thereby realizing a geological exploration core sampling device based on a core drill bit. This device, through the coordinated operation of multiple coaxial lifting components, can first perform annular pre-cutting of the target core, and then apply controllable axial force to achieve neat fracture. This effectively avoids end face damage, block breakage, or structural disturbance caused by forced pulling or ground impact during traditional core sampling, significantly improving the core recovery rate and the fidelity of the original geological information. It is especially suitable for non-destructive sampling of weak, broken, or high-value target layers, while being compatible with conventional wireline coring technology, and is highly efficient and reliable in operation.

[0012] To achieve the above-mentioned objectives, the technical solution of this invention is: a geological exploration core sampling device based on a core drill bit, comprising an outer tube, a liftable drill rod coaxially arranged inside the outer tube, a sampling drill bit coaxially fixed at the bottom end of the drill rod, a liftable inner tube coaxially arranged inside the drill rod, a liftable sampling tube coaxially arranged inside the inner tube, and a pre-cutting unit and a cutting unit coaxially arranged at the lower part of the drill rod to cooperate with the inner tube and the sampling tube, wherein the pre-cutting unit is located directly below the cutting unit and coaxially arranged.

[0013] In the above-mentioned core sampling device for geological exploration based on core drill bit, a drainage channel is formed between the outer tube and the drill rod. A cover plate is fixedly installed at the top of the outer tube, and a drainage port that runs through the top and bottom of the cover plate is opened. The drainage port is connected to the drainage channel.

[0014] The lower part of the drill rod has multiple water inlets that penetrate the inner tube and the sampling tube in the radial direction, and the water inlets are connected to the drainage channel.

[0015] In the above-mentioned core sampling device for geological exploration based on core drill bit, the drill rod is rotatably connected to the outer tube, a first guide groove is provided on the inner wall of the drill rod along its length, and a first boss adapted to the first guide groove is vertically fixed on the outer wall of the inner tube.

[0016] The inner wall of the inner tube is provided with a second guide groove along its length, and the outer wall of the sampling tube is provided with a second boss that matches the second guide groove.

[0017] In the above-mentioned core sampling device for geological exploration based on core drill bit, the drill rod is a tubular structure with openings at the top and bottom and its inner wall is a cylindrical structure, and the sampling drill bit is a tubular structure with openings at the top and bottom and its inner wall is a cylindrical structure.

[0018] The outer wall of the sampling drill bit is fixedly provided with multiple cutting edges for forming a ring-shaped rock core around its center, and the cutting edges are provided with multiple cutting teeth for breaking rocks.

[0019] In the above-mentioned core sampling device for geological exploration based on core drill bit, the pre-cutting unit includes a cutting ring, which is coaxially and fixedly connected to the bottom end of the inner tube. The outer wall of the cutting ring is in contact with the inner wall of the drill rod, and a blocking ring is coaxially and fixedly provided on the inner side of the bottom end of the cutting ring.

[0020] Multiple cutting rings are arranged below the cutting ring, forming a circular structure coaxial with the drill rod. The upper part of the outer wall of the cutting ring abuts against the inner wall of the drill rod, and there is a movable gap between adjacent cutting rings.

[0021] In the above-mentioned core sampling device for geological exploration based on core drill bit, the bottom outer wall of the blocking ring abuts against the top inner wall of the cutting ring, and a squeezing cavity is formed between the top of the cutting ring, the outer wall of the blocking ring, the bottom of the cutting ring, and the inner wall of the drill rod. A first spring is provided inside the squeezing cavity, and the first spring is coaxially arranged with the drill rod.

[0022] The top end of the first spring abuts against the cutting ring, and the bottom end of the first spring abuts against the top end of the cutting ring.

[0023] A limiting ring is coaxially fixed on the outer wall of the top end of the cutting ring, and the top end of the limiting ring abuts against the bottom end of the blocking ring.

[0024] In the above-mentioned core sampling device for geological exploration based on core drill bit, the top of the cutting ring at the lower part of the extrusion chamber is provided with grooves on both sides. The grooves are coaxially arranged with the cutting ring and a limiting plate is placed between adjacent grooves. The limiting plate is an arc-shaped structure adapted to the groove and a gap is left between the two ends of the limiting plate and the side wall of the groove.

[0025] The lower outer wall of the cutting ring is inclined towards the axis of the cutting ring. The top of the sampling drill bit is coaxially fixed with a pressing boss. The outer wall of the pressing boss abuts against the inner wall of the drill rod. A guide groove is vertically opened on the outer wall of the cutting ring. The top of the pressing boss is fixed with a guide boss that matches the corresponding guide groove.

[0026] A cutting blade is fixedly provided at the bottom end of the cutting ring. The bottom end of the cutting blade is inclined towards the axis of the cutting ring. When not cutting, the inner diameter of the cutting blade is larger than the inner diameter of the sampling drill bit.

[0027] In the above-mentioned core sampling device for geological exploration based on core drill bit, the cutting unit includes a compression ring coaxially arranged on the inner wall of the cutting ring. The inner wall of the compression ring can abut against the outer wall of the core. The lower inner wall of the cutting ring is inclined towards the axis of the cutting ring.

[0028] The outer wall of the extrusion ring is an inclined structure adapted to the inner wall of the cutting ring, the inner wall of the extrusion ring is a cylindrical structure, the extrusion ring is a radially retractable C-shaped structure, and the top end of the extrusion ring abuts against the bottom end of the sampling tube.

[0029] In the above-mentioned core sampling device for geological exploration based on core drill bit, a top plate is fixedly installed at the top of the drill rod to close its top opening, a fixing plate is fixedly installed at the top of the inner tube to close its top opening, and a sealing plate is fixedly installed at the top of the sampling tube to close its top opening.

[0030] A lifting rod is coaxially fixed at the top end of the inner tube. The upper part of the lifting rod passes through the top plate and the cover plate and extends out of the upper part of the cover plate. A retrieval platform adapted to an external retrieval device is coaxially fixed at the top end of the lifting rod. Positioning rings that limit the position of the cover plate are provided on the lifting rods on the upper and lower sides of the cover plate. The cover plate and the lifting rod are rotatably configured.

[0031] The bottom of the lifting rod extends through the closed plate into the interior of the sampling plate, and the bottom end of the lifting rod is coaxially fixed with a lifting plate.

[0032] In the above-mentioned core sampling device for geological exploration based on core drill bit, an elastic cavity is formed between the top end of the lifting plate, the bottom end of the sealing plate, and the sampling tube. A second spring is sleeved on the lifting rod inside the elastic cavity. The top end of the second spring abuts against the bottom end of the sealing plate, and the bottom end of the second spring abuts against the top end of the lifting plate.

[0033] A pressure chamber is formed between the sealing plate and the fixed plate. A pressure channel is coaxially opened in the middle of the lifting rod, penetrating the upper part of the lifting rod. Multiple liquid inlets connecting the pressure chamber and the pressure channel are horizontally opened in the middle of the lifting rod. A positioning plate is fixedly installed on the inner wall of the inner tube inside the pressure chamber to limit the extreme position of the top of the sealing plate.

[0034] An adjustment cavity is formed between the fixed plate and the top plate. A third spring is sleeved on the lifting rod inside the adjustment cavity. The top end of the third spring abuts against the bottom end of the top plate and the bottom end of the third spring abuts against the top end of the fixed plate. Multiple screws are vertically fixed to the top end of the fixed plate around its axis. The upper part of the screws penetrates the top plate and extends above the top plate. An adjusting nut that limits the maximum height between the top plate and the fixed plate is threaded onto the screws above the top plate.

[0035] Compared with the prior art, the core sampling device for geological exploration based on core drill bit of the present invention has at least the following beneficial effects:

[0036] 1. The present invention relates to a geological exploration core sampling device based on a core drill bit. This invention utilizes a three-stage coaxial nested structure of drill rod, inner tube, and sampling tube, with precise coordination between the first guide groove / first boss and the second guide groove / second boss, ensuring synchronous rotation and no relative torsion during drilling. This allows the core to smoothly slide into the sampling tube along the inner wall of the sampling drill bit after formation, avoiding core scraping, breakage, or jamming caused by inner tube shaking or deflection during traditional core sampling. Simultaneously, the sampling tube, as the innermost receiving cavity, provides full circumferential support for the core with its closed cylindrical inner wall, effectively protecting the original bedding and fracture structures of vulnerable cores such as those from weak interlayers, shale, and coal, significantly improving core recovery rate and geological information fidelity.

[0037] 2. The geological exploration core sampling device based on a core drill bit of the present invention integrates a pre-cutting unit and a cutting unit within the same device, and achieves precise timing control through a linkage mechanism of a lifting rod, spring, limiting ring, and extrusion boss. In the pre-cutting stage, the lifting rod is raised by the retrieval device, causing the inner tube and sampling tube to rise synchronously, releasing the radial constraint of the blocking ring on the cutting ring; continued lifting causes the drill rod to be lifted, and the cutting ring rotates with the drill rod under the cooperation of the guide groove and guide boss, and performs circumferential pre-cutting of the outer edge of the core through the extrusion boss and the inclined cutting edge at the bottom of the cutting ring, retaining the central connecting column. The limiting plate and the gap design of the sliding groove limit the cutting ring and ensure synchronous movement during pre-cutting. In the cutting stage, high-pressure liquid is injected through the pressure channel, pushing the sampling tube downwards. The extrusion ring is compressed radially and tightly adheres to the outer wall of the core, while simultaneously pushing the cutting ring downwards, cooperating with the rotation of the drill rod to complete the brittle fracture of the core along the pre-cut. This two-stage mechanism completely abandons the traditional crude cutting method that relies on ground hammering or forced pulling, ensuring that the upper and lower ends of the core are flat, without crushing or falling off.

[0038] 3. The core sampling device for geological exploration based on a core drill bit of the present invention constructs a three-stage elastic energy storage and buffer system. Furthermore, a first spring ensures the cutting ring remains in the same position during the initial lifting of the sampling tube; a second spring ensures the inner tube and sampling tube move synchronously during the initial lifting stage to prevent misalignment; and a third spring, in conjunction with a screw and adjusting nut, allows for on-site adjustment of the pre-compression of the inner tube assembly to adapt to the cutting force required for rock layers of different hardness. Simultaneously, the third spring delays the drill rod lifting time, ensuring that the blocking ring releases its radial constraint on the cutting ring.

[0039] 4. The core sampling device for geological exploration based on core drill bit of the present invention uses hydraulic drive to replace pure mechanical impact in the cutting unit, and the thrust is stable and controllable, avoiding tool damage due to instantaneous overload in hard rock, and also preventing core crushing due to excessive force in soft rock. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the overall structure of the geological exploration core sampling device based on a core drill bit according to the present invention;

[0041] Figure 2 This is a schematic diagram of the lower cross-sectional structure of the core sampling device for geological exploration based on a core drill bit according to the present invention;

[0042] Figure 3 This invention relates to a core sampling device for geological exploration based on a core drill bit. Figure 2 Enlarged view of region A in the middle;

[0043] Figure 4 This is a schematic diagram of the lower exploded structure of the core sampling device for geological exploration based on a core drill bit according to the present invention;

[0044] Figure 5 This is a schematic diagram of the explosive structure of the cutting ring and extrusion boss of the geological exploration core sampling device based on the core drill bit of the present invention;

[0045] Figure 6 This is a schematic diagram of the upper exploded structure of the core sampling device for geological exploration based on a core drill bit according to the present invention;

[0046] Figure 7 This is a schematic diagram of the upper cross-sectional structure of the core sampling device for geological exploration based on a core drill bit according to the present invention;

[0047] Figure 8 This is a schematic diagram of the upper section explosion structure of the core sampling device for geological exploration based on a core drill bit according to the present invention.

[0048] In the diagram: 1. Outer tube; 2. Drill rod; 3. Sampling drill bit; 4. Inner tube; 5. Sampling tube;

[0049] 6. Pre-cutting unit; 601. Cutting ring; 602. Blocking ring; 603. Cutting ring; 604. Extrusion chamber; 605. First spring; 606. Limiting ring; 607. Slide groove; 608. Limiting plate; 609. Extrusion boss; 610. Guide vertical groove; 611. Guide boss; 612. Cutting blade;

[0050] 71. Extrusion ring;

[0051] 8. Drainage channel; 9. Cover plate; 10. Drain outlet; 11. Inlet; 12. First guide groove; 13. First boss; 14. Second guide groove; 15. Second boss; 16. Cutting edge; 17. Cutting tooth; 18. Top plate; 19. Fixing plate; 20. Sealing plate; 21. Lifting rod; 22. Salvage platform; 23. Positioning ring; 24. Lifting plate; 25. Elastic cavity; 26. Second spring; 27. Pressure cavity; 28. Pressure channel; 29. ​​Liquid inlet; 30. Positioning plate; 31. Adjustment cavity; 32. Third spring; 33. Screw; 34. Adjusting nut. Detailed Implementation

[0052] The core sampling device for geological exploration based on a core drill bit of the present invention will be described in more detail below with reference to the accompanying drawings and specific embodiments.

[0053] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and 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 this invention.

[0054] See Figures 1-8 The core sampling device for geological exploration based on core drill bit in this embodiment, through the coordinated operation of multi-stage coaxial lifting components, can first perform annular pre-cutting of the target core, and then apply controllable axial force to achieve neat fracture. This effectively avoids end face damage, block falling or structural disturbance caused by forced pulling or ground impact during traditional core sampling, significantly improving the core recovery rate and the fidelity of the original geological information. It is especially suitable for non-destructive sampling of weak, broken or high-value target layers, while being compatible with conventional wireline coring technology, and is highly efficient and reliable in operation.

[0055] In this embodiment, it mainly includes an outer tube 1, inside which a liftable drill rod 2 is coaxially arranged. A drainage channel 8 is formed between the outer tube 1 and the drill rod 2. A cover plate 9 is fixedly installed at the top of the outer tube 1, and a through-hole 10 is opened on the cover plate 9, which is connected to the drainage channel 8. The outer tube 1 serves as the outer shell of the entire device, providing mechanical protection.

[0056] A sampling drill bit 3 is coaxially fixed at the bottom end of the drill rod 2 to form a rock core. A liftable inner tube 4 is coaxially arranged inside the drill rod 2, and a liftable sampling tube 5 is coaxially arranged inside the inner tube 4. Multiple water inlets 11 are radially arranged at the lower part of the drill rod 2, penetrating the inner tube 4 and the sampling tube 5. The water inlets 11 are connected to the drainage channel 8. The drill rod 2, through the water inlets 11 and the drainage channel 8, facilitates the circulation of flushing fluid and rock debris.

[0057] The drill rod 2 is rotatably connected to the outer tube 1. A first guide groove 12, extending along its length, is formed on the inner wall of the drill rod 2. A first boss 13, matching the first guide groove 12, is vertically fixed on the outer wall of the inner tube 4. This ensures that the inner tube 4 and the drill rod 2 rotate synchronously, preventing relative torsion. A second guide groove 14, extending along its length, is formed on the inner wall of the inner tube 4. A second boss 15, matching the second guide groove 14, is vertically fixed on the outer wall of the sampling tube 5. This ensures that the sampling tube 5 and the inner tube 4 rotate synchronously, preventing misalignment. The drill rod 2 is a tubular structure with openings at the top and bottom, and its inner wall is cylindrical. The sampling drill bit 3 is also a tubular structure with openings at the top and bottom, and its inner wall is cylindrical. Multiple cutting edges 16, used to form annular rock cores, are fixedly arranged around the center of the outer wall of the sampling drill bit 3. Multiple cutting teeth 17 for breaking rock are provided on the cutting edges 16. The cutting edge 16 and the cutting teeth 17 are located on the outer wall of the sampling drill bit 3 and are used to break the rock to form a ring-shaped core.

[0058] To achieve pre-cutting of the core, see Figures 1-5The lower part of the drill rod 2 is coaxially provided with a pre-cutting unit 6 and a cutting unit that cooperate with the inner tube 4 and the sampling tube 5. The pre-cutting unit 6 is located directly below the cutting unit and is coaxially arranged.

[0059] The pre-cutting unit 6 includes a cutting ring 601, which is coaxially and fixedly connected to the bottom end of the inner tube 4. The outer wall of the cutting ring 601 is in contact with the inner wall of the drill pipe 2. A blocking ring 602 is coaxially and fixedly installed on the inner side of the bottom end of the cutting ring 601. Located at the bottom end of the inner tube 4, it is used to fix the cutting ring 603 and release its radial constraint. Multiple cutting rings 603 are arranged below the cutting ring 601, forming a circular structure coaxial with the drill pipe 2. The upper part of the outer wall of the cutting ring 603 abuts against the inner wall of the drill pipe 2, and there is a movable gap between adjacent cutting rings 603. The annular pre-cutting of the rock core is achieved through the cutting rings 603.

[0060] The bottom outer wall of the blocking ring 602 abuts against the top inner wall of the cutting ring 603. A compression cavity 604 is formed between the top of the cutting ring 603, the outer wall of the blocking ring 602, the bottom of the cutting ring 601, and the inner wall of the drill rod 2. A first spring 605 is disposed inside the compression cavity 604, and the first spring 605 is coaxially disposed with the drill rod 2. The top of the first spring 605 abuts against the cutting ring 601, and the bottom of the first spring 605 abuts against the top of the cutting ring 603. This ensures that the position of the cutting ring 603 remains unchanged when the sampling tube 5 is initially lifted, until the blocking ring 602 releases its radial constraint on it. A limit ring 606 is coaxially fixed on the top outer wall of the cutting ring 603, and the top of the limit ring 606 abuts against the bottom of the blocking ring 602. The limiting ring 606 cooperates with the extrusion boss 609 to support the position of the blocking ring 602, ensuring that the initial position of the inner ring remains unchanged and that the position of the sampling tube 5 remains unchanged before it is lifted.

[0061] The cutting ring 603 at the lower part of the extrusion chamber 604 has grooves 607 on both sides of its top end. The grooves 607 are coaxially arranged with the cutting ring 603, and a limiting plate 608 is placed between adjacent grooves 607. The limiting plate 608 is an arc-shaped structure adapted to the groove 607, and there is a gap between the two ends of the limiting plate 608 and the side wall of the groove 607. This allows the cutting ring 603 to move radially synchronously, achieving pre-cutting as the drill rod 2 rotates. The lower outer wall of the cutting ring 603 is inclined towards the axis of the cutting ring 603. The top end of the sampling drill bit 3 is coaxially fixed with an extrusion boss 609. The outer wall of the extrusion boss 609 abuts against the inner wall of the drill rod 2. During the pre-cutting stage, it cooperates with the cutting ring 603 to guide the cutting ring 603 to perform circumferential pre-cutting of the rock core. The outer wall of the cutting ring 603 is vertically provided with a guide groove 610, and the top of the extrusion boss 609 is fixedly provided with a guide boss 611 that matches the corresponding guide groove 610. During the pre-cutting stage, the guide groove 610 and guide boss 611 cooperate to allow the cutting ring 603 to rotate with the drill rod 2, performing circumferential pre-cutting of the outer edge of the core. A cutting blade 612 is fixedly provided at the bottom end of the cutting ring 603. The bottom end of the cutting blade 612 is inclined towards the axis of the cutting ring 603, and the inner diameter of the cutting blade 612 before cutting is larger than the inner diameter of the sampling drill bit 3. Pre-cutting of the core is achieved through the cutting blade 612.

[0062] To achieve core cutting, see Figure 2 and Figure 4 The cutting unit includes a compression ring 71 coaxially disposed on the inner wall of a cutting ring 601. The inner wall of the compression ring 71 can abut against the outer wall of the core. The lower inner wall of the cutting ring 601 is inclined towards the axis of the cutting ring 601. The outer wall of the compression ring 71 is an inclined structure adapted to the inner wall of the cutting ring 601. The inner wall of the compression ring 71 is a cylindrical structure. The compression ring 71 is a radially contractible C-shaped structure. The top end of the compression ring 71 abuts against the bottom end of the sampling tube 5. After being compressed, it contracts radially and fits tightly against the outer wall of the core, cooperating with the cutting ring 601 to complete the brittle fracture of the core along the pre-cut.

[0063] For control of the organization, see [link to relevant documentation]. Figures 6-8The drill rod 2 has a top plate 18 fixedly installed at its top end to close its top opening. The inner tube 4 has a fixed plate 19 fixedly installed at its top end to close its top opening. The sampling tube 5 has a fixed plate 20 fixedly installed at its top end to close its top opening. A lifting rod 21 is coaxially fixedly installed at the top end of the inner tube 4. The upper part of the lifting rod 21 passes through the top plate 18 and the cover plate 9, extending out of the upper part of the cover plate 9. A retrieval platform 22 adapted to an external retrieval device is coaxially fixedly installed at the top end of the lifting rod 21 for docking with the external retrieval device to achieve overall lifting of the inner tube 4. Positioning rings 23 are provided on the lifting rods 21 on the upper and lower sides of the cover plate 9 to limit the position of the cover plate 9. The cover plate 9 and the lifting rod 21 are rotatably configured. The bottom of the lifting rod 21 passes through the closed plate 20 and extends into the interior of the sampling plate, and a lifting plate 24 is coaxially fixedly installed at the bottom end of the lifting rod 21.

[0064] An elastic cavity 25 is formed between the top end of the lifting plate 24, the bottom end of the sealing plate 20, and the sampling tube 5. A second spring 26 is sleeved on the lifting rod 21 inside the elastic cavity 25. The top end of the second spring 26 abuts against the bottom end of the sealing plate 20, and the bottom end of the second spring 26 abuts against the top end of the lifting plate 24. The elastic cavity 25 and the second spring 26 keep the inner tube 4 and the sampling tube 5 moving synchronously during the initial lifting stage, preventing misalignment. A pressure cavity 27 is formed between the sealing plate 20 and the fixing plate 19. A pressure channel 28 is coaxially opened in the middle of the lifting rod 21, penetrating the upper part of the lifting rod 21. Multiple liquid inlets 29 are horizontally opened in the middle of the lifting rod 21, connecting the pressure cavity 27 and the pressure channel 28. High-pressure liquid is injected through the pressure channel 28 and the liquid inlets 29 to push the sampling tube 5 downward, realizing the application of controllable axial force. A positioning plate 30 is fixedly installed on the inner wall of the inner tube 4 inside the pressure cavity 27 to limit the extreme position of the top end of the sealing plate 20. An adjustment cavity 31 is formed between the fixed plate 19 and the top plate 18. A third spring 32 is sleeved on the lifting rod 21 inside the adjustment cavity 31. The top end of the third spring 32 abuts against the bottom end of the top plate 18, and the bottom end of the third spring 32 abuts against the top end of the fixed plate 19. This delays the lifting time of the drill rod 2, ensuring that the blocking ring 602 releases the radial constraint on the cutting ring 603, and adjusts the pre-compression of the inner tube 4 assembly to adapt to the cutting force required for rock layers of different hardness. Multiple screws 33 are vertically fixed to the top end of the fixed plate 19 around its axis. The upper part of each screw 33 penetrates the top plate 18 and extends above it. An adjusting nut 34 is threaded onto the screw 33 above the top plate 18 to limit the extreme height between the top plate 18 and the fixed plate 19. This limits the extreme position of the top end of the sealing plate 20 and adjusts the extreme height between the top plate 18 and the fixed plate 19.

[0065] The method of using the core sampling device for geological exploration based on a core drill bit according to the present invention is as follows: First, the drilling rig drives the drill rod 2 to rotate through an external power system. Since the drill rod 2 and the outer tube 1 are connected by a rotating structure, the outer tube 1 itself does not participate in the rotation and only serves as a stationary load-bearing shell. The drill rod 2 transmits torque to the sampling drill bit 3 fixedly connected to its bottom end, causing the sampling drill bit 3 to rotate synchronously at high speed. The cutting edges 16 arranged circumferentially on the outer wall of the sampling drill bit 3 and the multiple cutting teeth 17 embedded on its surface perform annular crushing of the strata rock, gradually forming a hollow core column. The flushing fluid is pumped in from the ground and enters the interior of the drill rod 2 through multiple water inlets 11 opened radially at the bottom of the drill rod 2. It then passes through the gap between the inner tube 4 and the sampling tube 5 and finally sprays out from the central hole of the sampling drill bit 3, effectively cooling the drill bit and carrying rock cuttings upwards. The returned mud, carrying broken rock fragments, flows upward through the annular drainage channel 8 between the outer pipe 1 and the drill pipe 2, and is finally discharged into the surface circulation system through the drainage port 10 on the cover plate 9 fixed at the top of the outer pipe 1, thus completing the complete flushing, cooling and slag removal process.

[0066] After the target core section is drilled and sampled, the core cutting stage begins. At this point, the operator inserts a standard wireline coring tool into the drill pipe 2, ensuring reliable connection with the retrieval platform 22 at the top of the lifting rod 21. Subsequently, the retrieval tool is slowly lifted using a winch, causing the lifting rod 21 to move upwards. During the initial lifting phase, the second spring 26 is compressed, allowing the inner tube 4 and the sampling tube 5 to rise synchronously under the precise guidance of the first guide groove 12 and the first boss 13, and the second guide groove 14 and the second boss 15. This ensures no relative misalignment between the two, protecting the core already inside the sampling tube 5 from disturbance. As the lifting rod 21 continues to rise, the cutting ring 601 fixed at the bottom of the inner tube 4 moves upwards, and the integrated blocking ring 602 on its inner side also rises synchronously. At this time, the multiple cutting rings 603 in the pre-cutting unit 6 located below the cutting ring 601 are still kept in their original positions by the radial limiting effect of the outer wall of the bottom end of the blocking ring 602. Their positions are maintained by the first spring 605 in the extrusion chamber 604. The top end of the first spring 605 abuts against the cutting ring 601, and the bottom end abuts against the top end of the cutting ring 603, ensuring that the cutting ring 603 does not move upward with the inner tube 4 in the initial stage.

[0067] Meanwhile, a third spring 32 is installed inside the adjustment cavity 31 through which the upper part of the lifting rod 21 passes. The top end of the spring abuts against the bottom end of the top plate 18, and the bottom end abuts against the fixing plate 19 at the top of the inner tube 4. The third spring 32 acts as a buffer and delay at this stage, so that the drill rod 2 maintains its original axial position during the initial lifting process, avoiding premature triggering of the pre-cutting action. When the lifting rod 21 moves further upward, after the blocking ring 602 is completely freed from the radial constraint on the cutting ring 603, the third spring 32 begins to be compressed. Its stored energy is released, pushing the top plate 18 upward, and then driving the entire drill rod 2 and the sampling drill bit 3 fixed to it to rise synchronously through the top plate 18. At this time, the extrusion boss 609 integrally set at the top of the sampling drill bit 3 moves upward, and its outer wall fits tightly against the inner wall of the drill rod 2 to ensure effective force transmission. The extrusion boss 609 presses upward against the lower inclined outer wall of the cutting ring 603, using the inclined plane effect to convert the axial displacement into radial contraction force. Multiple cutting rings 603 achieve synchronous radial inward contraction under the cooperative constraint of the sliding groove 607 and the limiting plate 608. The limiting plate 608 has an arc-shaped structure and is embedded between the sliding grooves 607 at the top of adjacent cutting rings 603. Its two ends maintain a small gap with the sidewall of the sliding groove 607, which allows the cutting rings 603 to rotate freely in the circumferential direction, while ensuring that their movement is consistent and does not deviate during radial contraction.

[0068] As drill pipe 2 is driven upward, its rotation continues. At this time, the guide boss 611 at the top of the extrusion boss 609 fits precisely into the vertical guide groove 610 on the outer wall of the cutting ring 603, forming a reliable circumferential transmission pair. Thus, the cutting ring 603 rotates synchronously with drill pipe 2 under the cooperation of the guide groove 610 and the guide boss 611. The cutting edge 612 at the bottom of the cutting ring 603 has an inwardly inclined structure, and its inner diameter is slightly larger than the inner diameter of the sampling drill bit 3, ensuring that it does not interfere with the core when not activated. Under the combined motion of rotation and radial contraction, the cutting edge 612 performs annular pre-cutting on the outer edge of the formed core, precisely cutting out a continuous and uniform annular groove, retaining only the core connecting column in the center, creating an ideal fracture path for subsequent controllable fracture.

[0069] After pre-cutting, the core cutting stage begins. At this time, high-pressure liquid is injected into the pressure channel 28 inside the lifting rod 21 via a ground pump station. The liquid flows into the pressure chamber 27 formed between the sealing plate 20 and the fixed plate 19 through multiple horizontally opened inlets 29 in the middle of the lifting rod 21. As the hydraulic pressure increases, the hydraulic pressure in the pressure chamber 27 acts on the bottom end of the sealing plate 20, overcoming the elastic force of the second spring 26 and pushing the sampling tube 5 downward relative to the inner tube 4. The bottom end of the sampling tube 5 presses against the compression ring 71 in the cutting unit. This compression ring 71 has a C-shaped radially retractable structure, and its outer wall matches the inclined surface of the inner wall of the cutting ring 601. Under axial pressure, the compression ring 71 slides inward along the inclined surface, generating radial contraction, causing its inner wall to tightly cover the outer surface of the core, providing uniform clamping force. Simultaneously, the downward movement of the sampling tube 5 further pushes the cutting ring 601 downward through the compression ring 71, causing the root of the core to bear controllable axial tensile stress. With the assistance of continuous low-speed rotation of drill pipe 2, the core undergoes brittle fracture along the previously pre-cut weak annular groove, achieving a clean, crush-free, and high-quality cut without any fragmentation. This hydraulic drive method abandons the traditional crude methods that rely on impact or forced pulling. The thrust is stable and adjustable, which can avoid tool damage caused by instantaneous overload in hard rock, and prevent crushing or deformation of soft core due to local stress concentration.

[0070] After the core sample is successfully cut, the retrieval device continues to lift the lifting rod 21. At this time, the lifting rod 21, through the linkage of the fixing plate 19, the top plate 18, and various springs, drives the inner tube 4, the sampling tube 5, the drill rod 2, and the outermost outer tube 1 to rise synchronously. Since the outer tube 1 only moves up and down without rotating, the rotating connection structure between it and the drill rod 2 ensures a smooth lifting process. The entire assembly is lifted out of the borehole step by step until it is completely retrieved to the surface. The operator then disassembles the device, removes the sampling tube 5, and obtains a high-fidelity core sample with a flat end face, complete structure, and clear bedding. The entire process requires no additional power source, is fully compatible with standard wireline coring technology, is highly efficient and reliable, and significantly improves the core recovery rate and the fidelity of the original geological information.

[0071] Unless otherwise defined, the technical or scientific terms used herein should be understood in their ordinary sense as would be understood by one of ordinary skill in the art to which this invention pertains. The use of terms such as "a" or "an" in this specification and claims does not necessarily indicate a limitation of quantity. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0072] The exemplary embodiments of the present invention have been described in detail above with reference to preferred embodiments. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of the present invention, and various combinations can be made to the various technical features and structures proposed in the present invention without exceeding the protection scope of the present invention.

Claims

1. A core sampling device for geological exploration based on a core drill bit, characterized by: The device includes an outer tube (1), a liftable drill rod (2) is coaxially arranged inside the outer tube (1), a sampling drill bit (3) is coaxially fixed at the bottom end of the drill rod (2), a liftable inner tube (4) is coaxially arranged inside the drill rod (2), a liftable sampling tube (5) is coaxially arranged inside the inner tube (4), and a pre-cutting unit (6) and a cutting unit that cooperate with the inner tube (4) and the sampling tube (5) are coaxially arranged at the lower part of the drill rod (2). The pre-cutting unit (6) is located directly below the cutting unit and is coaxially arranged. The pre-cutting unit (6) includes a cutting ring (601), which is coaxially and fixedly connected to the bottom end of the inner tube (4). The outer wall of the cutting ring (601) is in contact with the inner wall of the drill rod (2). A blocking ring (602) is coaxially and fixedly provided on the inner side of the bottom end of the cutting ring (601). Multiple cutting rings (603) are provided below the cutting ring (601). The multiple cutting rings (603) form a circular structure coaxial with the drill rod (2). The upper part of the outer wall of the cutting ring (603) abuts against the inner wall of the drill rod (2). There is a movable gap between adjacent cutting rings (603). The bottom outer wall of the blocking ring (602) abuts against the top inner wall of the cutting ring (603). A squeezing cavity (604) is formed between the top of the cutting ring (603), the outer wall of the blocking ring (602), the bottom of the cutting ring (601), and the inner wall of the drill rod (2). A first spring (605) is provided inside the squeezing cavity (604). The first spring (605) is coaxially arranged with the drill rod (2). The top of the first spring (605) abuts against the cutting ring (601), and the bottom of the first spring (605) abuts against the top of the cutting ring (603). A limiting ring (606) is coaxially fixed on the top outer wall of the cutting ring (603). The top of the limiting ring (606) abuts against the bottom of the blocking ring (602). The cutting ring (603) at the bottom of the extrusion chamber (604) has grooves (607) on both sides of its top end. The grooves (607) are coaxially arranged with the cutting ring (603) and a limiting plate (608) is placed between adjacent grooves (607). The limiting plate (608) is an arc-shaped structure adapted to the groove (607) and there is a gap between the two ends of the limiting plate (608) and the side wall of the groove (607). The lower outer wall of the cutting ring (603) is inclined towards the axis of the cutting ring (603). The top of the sampling drill bit (3) is coaxially fixed with a pressing boss (609). The outer wall of the pressing boss (609) abuts against the inner wall of the drill rod (2). The outer wall of the cutting ring (603) is vertically provided with a guide groove (610). The top of the pressing boss (609) is fixed with a guide boss (611) that matches the corresponding guide groove (610). The bottom end of the cutting ring (603) is fixed with a cutting blade (612). The bottom end of the cutting blade (612) is inclined towards the axis of the cutting ring (603). When not cutting, the inner diameter of the cutting blade (612) is larger than the inner diameter of the sampling drill bit (3). The cutting unit includes a compression ring (71) coaxially arranged on the inner wall of the cutting ring (601). The inner wall of the compression ring (71) can abut against the outer wall of the core. The lower inner wall of the cutting ring (601) is inclined towards the axis of the cutting ring (601). The outer wall of the compression ring (71) is an inclined structure adapted to the inner wall of the cutting ring (601). The inner wall of the compression ring (71) is a cylindrical structure. The compression ring (71) is a C-shaped structure that can be radially contracted. The top end of the compression ring (71) abuts against the bottom end of the sampling tube (5).

2. The core bit based geological exploration core sampling device of claim 1, wherein: A drainage channel (8) is formed between the outer tube (1) and the drill rod (2). A cover plate (9) is fixedly installed at the top of the outer tube (1). A drainage port (10) is opened on the cover plate (9) and runs through it from top to bottom. The drainage port (10) is connected to the drainage channel (8). The lower part of the drill rod (2) has multiple water inlets (11) that penetrate the inner tube (4) and the sampling tube (5) in the radial direction, and the water inlets (11) are connected to the drainage channel (8).

3. The core bit based geological exploration core sampling device of claim 2, wherein: The drill rod (2) is rotatably connected to the outer tube (1). A first guide groove (12) is provided on the inner wall of the drill rod (2) along its length direction. A first boss (13) that matches the first guide groove (12) is vertically fixed on the outer wall of the inner tube (4). The inner wall of the inner tube (4) is provided with a second guide groove (14) arranged along its length direction, and the outer wall of the sampling tube (5) is provided with a second boss (15) that matches the second guide groove (14).

4. The core bit based geological exploration core sampling device of claim 3, wherein: The drill rod (2) is a tubular structure with openings at the top and bottom and its inner wall is a cylindrical structure. The sampling drill bit (3) is a tubular structure with openings at the top and bottom and its inner wall is a cylindrical structure. The outer wall of the sampling drill bit (3) is fixedly provided with a plurality of cutting edges (16) for forming a ring-shaped rock core around its center, and the cutting edges (16) are provided with a plurality of cutting teeth (17) for breaking rocks.

5. The geological exploration core sampling device based on a core drill bit according to claim 4, characterized in that: The top of the drill rod (2) is fixedly provided with a top plate (18) that closes its top opening, the top of the inner tube (4) is fixedly provided with a fixing plate (19) that closes its top opening, and the top of the sampling tube (5) is fixedly provided with a sealing plate (20) that closes its top opening. A lifting rod (21) is coaxially fixed at the top of the inner tube (4). The upper part of the lifting rod (21) passes through the top plate (18) and the cover plate (9) and extends out of the upper part of the cover plate (9). A retrieval platform (22) adapted to an external retrieval device is coaxially fixed at the top of the lifting rod (21). Positioning rings (23) that limit the position of the cover plate (9) are provided on the lifting rods (21) on the upper and lower sides of the cover plate (9). The cover plate (9) and the lifting rod (21) are rotatably arranged. The bottom of the lifting rod (21) extends through the closed plate (20) into the interior of the sampling plate, and the bottom end of the lifting rod (21) is coaxially fixed with the lifting plate (24).

6. The core bit based geological exploration core sampling device of claim 5, wherein: An elastic cavity (25) is formed between the top end of the lifting plate (24), the bottom end of the sealing plate (20), and the sampling tube (5). A second spring (26) is sleeved on the lifting rod (21) inside the elastic cavity (25). The top end of the second spring (26) abuts against the bottom end of the sealing plate (20), and the bottom end of the second spring (26) abuts against the top end of the lifting plate (24). A pressure chamber (27) is formed between the sealing plate (20) and the fixed plate (19). A pressure channel (28) is coaxially opened in the middle of the lifting rod (21) and passes through the upper part of the lifting rod (21). A plurality of liquid inlets (29) connecting the pressure chamber (27) and the pressure channel (28) are horizontally opened in the middle of the lifting rod (21). A positioning plate (30) is fixedly installed on the inner wall of the inner tube (4) inside the pressure chamber (27) to limit the extreme position of the top of the sealing plate (20). An adjustment cavity (31) is formed between the fixed plate (19) and the top plate (18). A third spring (32) is sleeved on the lifting rod (21) inside the adjustment cavity (31). The top end of the third spring (32) abuts against the bottom end of the top plate (18) and the bottom end of the third spring (32) abuts against the top end of the fixed plate (19). A plurality of screws (33) are vertically fixed on the top end of the fixed plate (19) around its axis. The upper part of the screws (33) penetrates the top plate (18) and extends above the top plate (18). An adjusting nut (34) that limits the extreme height between the top plate (18) and the fixed plate (19) is threaded onto the screws (33) above the top plate (18).

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