In-situ stress measurement drilling instrument and measurement method

Abstract

This invention discloses an in-situ stress measurement borehole instrument and method, comprising an outer shell, a support, and a drilling assembly. The outer shell is fitted onto the support. The drilling assembly includes a linkage sleeve, a linkage cylinder, and a drill bit. The linkage sleeve is rotatably mounted on the support, and its axis is set along the width direction of the in-situ stress measurement borehole instrument. A transmission wheel is integrally connected to the outer circumference of the linkage sleeve. The linkage cylinder is coaxially fitted inside the linkage sleeve, and its outer circumference and the inner circumference of the linkage sleeve are axially slidingly connected by a spline and can maintain synchronous rotation. The drill bit is installed inside the linkage cylinder, with a portion of the drill bit protruding outside the linkage cylinder. This invention, through the cooperation of the drill bit and a strain sensor, allows the strain sensor to be installed on the rock surface inside the borehole wall first, and then the drill bit to drill through the rock at the installation location of the strain sensor, enabling stress detection inside the rock mass.

Description

Technical Field

[0001] This invention relates to rock mass testing equipment, and more specifically, to an in-situ stress measurement borehole instrument and an in-situ stress measurement method. Background Technology

[0002] In-situ stress is the natural stress existing in underground rock masses. It is the sum of stresses generated in the rock mass by various mechanical forces inside the Earth. Its state directly affects the design, construction safety, and rock mass stability assessment of underground engineering projects.

[0003] When measuring in-situ stress, it is usually necessary to attach strain sensors to the surface of the rock mass. These strain sensors are high-precision strain gauges that can continuously detect stress changes in the rock mass. By drilling into the rock mass at the corresponding location, stress can be released, and the stress changes in the rock mass can be obtained.

[0004] Currently, due to limitations in testing equipment, rock mass stress testing can typically only be performed on rock masses exposed on the surface. To test the stress at a certain depth within the rock mass, it is necessary to first drill holes to a certain depth, then operate inside the holes. Strain sensors need to be attached to the surface of the rock mass inside the holes, and the stress at the corresponding location needs to be released before the stress at the corresponding depth can be tested. However, current testing equipment cannot meet the testing requirements for the interior of the rock mass.

[0005] Therefore, a new solution is needed to address this problem. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide an in-situ stress measurement drilling instrument and measurement method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: an in-situ stress measurement drilling instrument, comprising an outer shell, a support, and a drilling assembly, wherein the outer shell is fitted onto the support; the drilling assembly comprises a linkage sleeve, a linkage cylinder, and a drill bit; the linkage sleeve is rotatably mounted on the support, and the axis of the linkage sleeve is arranged along the width direction of the in-situ stress measurement drilling instrument; a transmission wheel is integrally connected to the outer circumference of the linkage sleeve; the linkage cylinder is coaxially fitted inside the linkage sleeve, and the outer circumference of the linkage cylinder and the inner circumference of the linkage sleeve are axially slidingly connected by a spline and can maintain synchronous rotation; the drill bit is installed inside the linkage cylinder, and a portion of the drill bit protrudes outside the linkage cylinder;

[0008] It also includes a movable seat and a second cylinder. The movable seat is provided on the side of the drilling assembly facing away from the drill bit. The movable seat is slidably mounted on the bracket along the coaxial direction of the linkage sleeve. The second cylinder is mounted on the bracket and can drive the movable seat to slide.

[0009] It also includes a motor, a coupling, a steering gear, and a first transmission wheel. The motor and the steering gear are both fixedly mounted on the bracket. The output end of the motor is connected to the input end of the steering gear through a coupling. The first transmission wheel is installed on the output end of the steering gear, and the first transmission wheel and the second transmission wheel are mutually connected for transmission.

[0010] The present invention is further configured such that a support block and a cylinder are installed at both ends of the bracket, the support block is slidably installed along the width direction of the in-situ stress measuring drilling instrument, and the cylinder is used to drive the adjusting cylinder.

[0011] The invention is further configured such that the axis of the motor output end is set along the length direction of the in-situ stress measuring drilling instrument, and the axis of the output end of the steering device is perpendicular to each other; the first transmission wheel and the second transmission wheel are both sprockets and are driven by chains.

[0012] The invention is further configured such that the outer periphery of the linkage sleeve is rotatably mounted on the bracket via a bearing, which restricts the axial movement of the linkage sleeve; one end of the linkage cylinder faces the movable seat, and a bearing is mounted on the linkage cylinder and the movable seat. The bearing is a plane bearing used to transmit the axial load of the linkage cylinder.

[0013] The invention is further configured such that a bearing mounting groove is provided on the side of the movable seat facing the linkage cylinder, and the second bearing is embedded in the bearing mounting groove; a magnetic suction ring is installed on the side of the movable seat facing away from the linkage cylinder, and the magnetic suction ring is used to magnetically attract the second bearing and the linkage cylinder to move closer to the movable seat.

[0014] The invention is further configured such that the drill bit has an annular structure; it also includes a cylinder three and a strain sensor, the strain sensor being located on the inner circumference of the drill bit and being able to extend out of the drill bit via the cylinder three.

[0015] The invention is further configured such that the movable seat has a through hole, the through hole is directly opposite the inner circumference of the drill bit, and the cylinder three is provided through the through hole; the cylinder three is mounted on the bracket and has a telescopic rod that can extend and retract, the telescopic rod extends into the drill bit along the axial direction of the linkage sleeve, and the strain sensor is mounted on the telescopic rod.

[0016] The invention is further configured such that a plurality of nails are provided on the outward side of the strain sensor, the nails being able to be driven into and installed in the rock mass; the drill bit is used to drill holes in the rock mass surrounding the strain sensor.

[0017] The present invention is further configured such that the strain sensor includes a support base and three sets of rotating rods. The support base is fixedly installed on the telescopic rod, and three sets of connecting blocks are fixedly installed on the outer periphery of the support base. The three sets of rotating rods are rotatably connected to the three sets of connecting blocks respectively. The rotation axis of the rotating rod is perpendicular to the telescopic rod. The rotating rod has a first end facing away from the cylinder and a second end facing the cylinder. The first end of the rotating rod is connected to a mounting nail, and a pre-bending sensing plate is installed between the second ends of adjacent rotating rods.

[0018] The present invention is further configured such that the strain sensor pushes outward in the opposite direction to the support block pushing outward;

[0019] This invention also provides an in-situ stress measurement method, employing the in-situ stress measurement borehole apparatus as described above. During the detection process, a hole is first drilled in the rock mass, and then the in-situ stress measurement borehole apparatus is placed inside the hole. A cylinder pushes a support block outwards, fixing the in-situ stress measurement borehole apparatus within the hole. A cylinder pushes a strain sensor outwards, embedding it into the rock surface, and the strain sensor detects the stress on the rock surface. The drill bit rotates, and simultaneously, a cylinder pushes the drill bit outwards, drilling into the rock mass surrounding the strain sensor. During drilling, the strain sensor continuously detects stress changes on the rock surface.

[0020] In summary, the present invention has the following beneficial effects:

[0021] By placing the in-situ stress measurement borehole instrument into a hole in the rock mass, the instrument can be fixed inside the hole by two sets of support blocks. Then, by working together with the drill bit and strain sensor, the strain sensor can be installed on the surface of the rock mass inside the borehole wall. Then, the drill bit drills into the rock mass at the installation position of the strain sensor. During the drilling process, the stress in the rock mass at the installation position of the strain sensor will be contacted, thereby allowing the stress change of the rock mass to be checked, and stress detection can be achieved inside the rock mass.

[0022] By setting the strain sensor as a nail-like mounting structure, and using cylinder three to apply pressure to the strain sensor, part of the strain sensor can be nailed into the rock mass, simplifying the installation method of the strain sensor and replacing the bonding method in the prior art. The installation of the strain sensor does not require adhesive, which simplifies the structure corresponding to the adhesive storage, extrusion and curing steps in the strain sensor attachment process, thereby simplifying the entire detection operation process. In addition, since the strain sensor is nailed into the rock mass, and with the pressure of cylinder three, the strain sensor can always be kept in a pressure fixed state with the rock surface, which can also avoid the problem of strain sensor delamination in the traditional bonding method. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of an in-situ stress measurement borehole apparatus in this embodiment;

[0024] Figure 2 This is a perspective view of an in-situ stress measurement drilling instrument in this embodiment;

[0025] Figure 3 This is a cross-sectional view of an in-situ stress measurement drilling instrument in this embodiment;

[0026] Figure 4 This is a schematic diagram of the internal structure of an in-situ stress measurement borehole drill in this embodiment. Figure 1 ;

[0027] Figure 5 for Figure 4 Enlarged view of a portion of the image;

[0028] Figure 6 This is a schematic diagram of the internal structure of an in-situ stress measurement borehole drill in this embodiment. Figure 2 ;

[0029] Figure 7 for Figure 6 Enlarged view of a portion of the image;

[0030] Figure 8 This is a cross-sectional view of the drilling assembly in this embodiment;

[0031] Figure 9 This is an exploded view of the drilling assembly in this embodiment;

[0032] Figure 10 This is a schematic diagram of the strain sensor in this embodiment.

[0033] Reference numerals: Drilling instrument body 100; outer shell 1; clearance port one 101; clearance port two 102; bracket 2; support block 3; cylinder one 301; drilling assembly 4; linkage sleeve 401; transmission wheel two 402; bearing one 403; linkage cylinder 404; drill bit 405; bearing two 406; magnetic ring body 407; motor 5; coupling 501; steering gear 502; transmission wheel one 503; chain 504; movable seat 7; cylinder two 701; slide rail 702; through hole 703; bearing mounting groove 704; strain sensor 8; rotating shaft 800; support seat 801; connecting block 802; rotating rod 803; first end 804; second end 805; nail body 806; pre-bending sensing plate 807; cylinder three 9; telescopic rod 901. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0035] This embodiment discloses an in-situ stress measurement borehole apparatus, referring to... Figures 1-10 As shown, the main body of the in-situ stress measurement borehole instrument has a cylindrical structure and a narrow and long shape, which can be embedded and installed in the hole of the rock mass.

[0036] Reference Figures 1-4 As shown, the in-situ stress measurement drilling instrument includes components such as a housing 1, a support 2, and a drilling assembly 4. The support 2 serves as the internal support for the entire instrument, while the housing 1 is fitted over the support 2, providing protection for the support 2 and other components, resulting in a relatively smooth outer perimeter of the instrument. The housing 1 is roughly cylindrical in shape, with its axial direction being the length direction of the in-situ stress measurement drilling instrument and its radial direction being the width direction.

[0037] Clamping components are installed at both ends of the in-situ stress measuring drilling instrument to clamp and limit its position. Specifically, support blocks 3 and cylinders 301 are installed at both ends of the bracket 2. The support blocks 3 have an arc-shaped structure that matches the shape of the outer shell 1, and a matching clearance opening 101 is opened at the corresponding position of the outer shell 1 to facilitate the outward ejection of the support blocks 3.

[0038] The support block 3 is slidably installed on the bracket 2, and the sliding direction is along the width direction of the in-situ stress measuring borehole instrument. The cylinder 301 is installed on the bracket 2, and the telescopic end of the cylinder 301 is connected to the support block 3. The cylinder 301 can drive the support block 3 to be pushed outward to the outside of the in-situ stress measuring borehole instrument, and can abut against the inner wall of the hole in the rock mass, thereby fixing the in-situ stress measuring borehole instrument in the hole of the rock mass.

[0039] Reference Figures 4-9 As shown, the drilling assembly 4 includes a linkage sleeve 401, a linkage cylinder 404, and a drill bit 405. The outer periphery of the linkage sleeve 401 is rotatably mounted on the bracket 2 via a bearing 403. The bearing 403 can be a deep groove ball bearing. The outer ring of the bearing 403 is fixed by mounting it on the bearing seat of the bracket 2, while the inner ring of the bearing 403 is fitted onto the outer periphery of the linkage sleeve 401. A convex ring and a limiting snap ring are used to block the axial movement of the linkage sleeve 401 between the linkage sleeve 401 and the inner ring of the bearing 403.

[0040] The linkage sleeve 401 is rotatably mounted on the bracket 2, and the axis of the linkage sleeve 401 is set along the width direction of the in-situ stress measuring drilling instrument. A transmission wheel 402 is integrally connected to the outer circumference of the linkage sleeve 401, and the transmission wheel 402 can be connected to the power mechanism for transmission.

[0041] The linkage cylinder 404 is coaxially sleeved within the linkage sleeve 401. A spline structure is machined on the outer circumference of the linkage cylinder 404 and the inner circumference of the linkage sleeve 401, allowing the linkage cylinder 404 to slide axially relative to the linkage sleeve 401 and transmitting axial rotational torque through the spline structure, thus maintaining synchronous rotation between the linkage cylinder 404 and the linkage sleeve 401. The drill bit 405 is installed inside the linkage cylinder 404, fixedly mounted thereto, with a portion of the drill bit 405 protruding outside the linkage cylinder 404. The drill bit 405 allows drilling into the inner wall surface of the rock mass.

[0042] Furthermore, during the drilling process of the drill bit 405 on the rock surface, not only axial rotation but also axial sliding is required. Therefore, this embodiment also includes a movable seat 7 and a second cylinder 701. The movable seat 7 is provided on the side of the drilling assembly 4 facing away from the drill bit 405, and the movable seat 7 is slidably mounted on the bracket 2 along the coaxial direction of the linkage sleeve 401. The second cylinder 701 is mounted on the bracket 2, and the telescopic end of the second cylinder 701 is connected to the movable seat 7, enabling the second cylinder 701 to apply sliding adjustment power to the movable seat 7.

[0043] One end of the linkage cylinder 404 faces the movable seat 7, and a bearing 406 is installed between the end of the linkage cylinder 404 and the movable seat 7. The movable seat 7 has a bearing mounting groove 704 on the side facing the linkage cylinder 404, and the bearing 406 can be embedded in the bearing mounting groove 704. The bearing 406 is a plane bearing and is used to transmit the axial load of the linkage cylinder 404.

[0044] During the drilling process of drill bit 405, cylinder 2 701 drives movable seat 7 to slide. Movable seat 7 can abut against the end of bearing 2 406 and linkage cylinder 404, thereby applying axial drilling pressure to linkage cylinder 404 and realizing drill bit 405 drilling on rock surface.

[0045] Additionally, a magnetic ring 407 is installed on the side of the movable seat 7 facing away from the linkage cylinder 404. The magnetic ring 407 magnetically attracts the bearing 406 and the linkage cylinder 404, allowing them to move closer to the movable seat 7. After drilling is completed, the cylinder 701 moves back. At this time, the magnetic ring 407 drives the bearing 406 and the linkage cylinder 404, causing the drill bit 405 to also slide back from the follower position, allowing it to be removed from the rock surface and retracted back into the instrument.

[0046] Because a high axial load needs to be applied during the drilling process of drill bit 405, in this embodiment, two sets of cylinders 701 are used to drive the movable seat 7 simultaneously. The cylinders 701 are located on both sides of the movable seat 7, and drill bit 405 is positioned precisely between the two cylinders 701, which can stably and effectively apply time-dependent load pressure to the movable seat 7.

[0047] To improve the sliding stability of the movable seat 7, the movable seat 7 can be slidably connected to the support 2 through multiple sets of slide rails 702 to maintain the stability of the sliding trajectory of the movable seat 7 and maintain stability during the drilling process.

[0048] In this embodiment, the drill bit 405 is driven to rotate using components such as a motor 5, a coupling 501, a steering gear 502, and a transmission wheel 503. Specifically, the motor 5 and the steering gear 502 are both fixedly mounted on the bracket 2. The motor 5 is a geared motor, and the axis of the output end of the motor 5 is set along the length direction of the in-situ stress measuring drilling instrument, so that the overall length direction of the motor 5 is consistent with the overall length direction of the instrument.

[0049] The steering gear 502 has a rotatable input end and a deflector end, which are arranged perpendicular to each other. The output end of the motor 5 is connected to the input end of the steering gear 502 via a coupling 501. The steering gear 502 can rotate the output axis of the motor 5 by 90° to drive the drill bit 405. The steering gear 502 contains a dimensional transmission structure, such as a bevel gear structure, which will not be described in detail.

[0050] A first transmission wheel 503 is installed at the output end of the steering gear 502. The first transmission wheel 503 can be driven by the rotation of the motor 5 to realize the output of power. The first transmission wheel 503 and the second transmission wheel 402 are connected to each other, so that the second transmission wheel 402 can be driven to rotate. Specifically, both the first transmission wheel 503 and the second transmission wheel 402 are sprockets, and a chain 504 is installed between them, so that the first transmission wheel 503 and the second transmission wheel 402 can be driven to each other through the chain 504.

[0051] The linkage sleeve 401 is integrally and fixedly connected to the transmission wheel 402. During the rotation of the transmission wheel 402, the linkage sleeve 401 is driven to rotate. The linkage sleeve 401 and the linkage cylinder 404 are then rotated through a spline structure. The drill bit 405 rotates synchronously with the linkage cylinder 404. The rotation of the drill bit 405 enables the rotation.

[0052] In this embodiment, the drill bit 405 has a ring-shaped structure, and the in-situ stress measurement borehole apparatus also includes a cylinder 9 and a strain sensor 8. The strain sensor 8 is located on the inner circumference of the drill bit 405 and can extend out of the drill bit 405 through the cylinder 9. The strain sensor 8 can be installed on the inner wall of the rock borehole, thereby enabling the detection of stress in the rock mass. By drilling around the strain sensor 8 with the drill bit 405, a borehole can be drilled in the rock mass around the strain sensor 8, allowing the rock mass to release stress, and the strain sensor 8 can detect the stress change state of the rock mass. Specifically, the diameter of the drill bit 405 is approximately 30 mm, and the drilling depth can be specifically set according to the detection needs.

[0053] In this embodiment, the movable seat 7 has a through hole 703, which is directly opposite the inner circumference of the drill bit 405. Furthermore, the cylinder 9 is mounted on the bracket 2 and passes through the through hole 703 of the movable seat 7. The cylinder 9 has a telescopic rod 901 that extends into the drill bit 405 along the axial direction of the linkage sleeve 401, and the strain sensor 8 is mounted on the telescopic rod 901. By extending and retracting the telescopic rod 901 of the cylinder 9, the strain sensor 8 can be adjusted and controlled, allowing it to be installed on the inner wall surface of the borehole in the rock mass.

[0054] Reference Figure 10 As shown, the strain sensor 8 has several nails 806 on its outward-facing side. These nails 806 allow it to be driven into the rock mass, with the driving pressure coming from the cylinder 9. After the cylinder 9 pushes out the strain sensor 8, it drives the nails 806 of the strain sensor 8 into the rock surface. The outward-pushing direction of the strain sensor 8 is opposite to the outward-pushing direction of the support block 3. During the driving process into the rock mass, the opposing force of the support block 3 ensures that the strain sensor 8 can be stably driven into the rock surface.

[0055] Generally, the holes drilled in the rock mass are circular, and the inner wall of the hole forms an arc-shaped surface. The arc-shaped surface does not affect the installation of the strain sensor 8. During the driving process, the three nails 806 of the strain sensor 8 will be pressed into the inner wall of the hole to a certain depth, which can effectively connect the strain sensor 8 with the inner wall of the hole. Combined with the pressure on the strain sensor 8, the strain sensor 8 can be stably fixed to the inner wall surface of the hole, so that the strain detection test can be carried out normally.

[0056] Specifically, the strain sensor 8 includes a support base 801 and three sets of rotating rods 803. The support base 801 is fixedly installed on the telescopic rod 901, so that the strain sensor 8 can be connected to the telescopic rod 901 of the cylinder 3 9, serving as a support for the strain sensor 8.

[0057] In addition, three sets of connecting blocks 802 are fixedly installed on the outer periphery of the support base 801. The connecting blocks 802 and the support base 801 are an integral structure. Three sets of rotating rods 803 are rotatably connected to the three sets of connecting blocks 802 respectively. The rotating rods 803 are connected to the connecting blocks 802 through the rotating shaft 800. The direction of the rotating rods 803 is roughly parallel to the length direction of the telescopic rod 901. The rotation axis of the rotating rods 803 is perpendicular to the telescopic rod 901.

[0058] The rotating rod 803 has a first end 804 facing away from the cylinder 9 and a second end 805 facing the cylinder 9. The rotating shaft 800 is positioned close to the first end 804, thus forming a shorter lever arm at the first end 804 and a longer lever arm at the second end 805. A nail body 806 is mounted at the first end 804 of the rotating rod 803. The tip of the nail body 806 extends away from the rotating rod 803, towards the inner wall of the rock mass, and in the same direction as the extension direction of the telescopic rod 901.

[0059] In addition, three pre-bending induction plates 807 are installed between the second ends 805 of adjacent rotating rods 803, forming a roughly circular structure. The substrate of the pre-bending induction plate 807 is an arc-shaped steel sheet with strain sensors attached to its surface. The first end 804 of the rotating rod 803 is driven into the surface of the rock mass. When the rock mass experiences strain, the first end 804 of the rotating rod 803 will generate a small strain. The rotating rod 803 forms a lever-like structure, which amplifies the strain at the second end 805 of the rotating rod 803. The pre-bending induction plate 807 can then detect this strain, thereby detecting the stress change state of the rock mass.

[0060] This embodiment discloses an in-situ stress measurement method, which uses the in-situ stress measurement borehole instrument as described above to measure the stress parameters of the rock mass. During the detection process, a hole is first drilled in the rock mass, and the size of the hole is adapted to the size of the in-situ stress measurement borehole instrument. Then, the in-situ stress measurement borehole instrument is placed in the hole of the rock mass. By pushing the support block 3 outward by the cylinder 301, the in-situ stress measurement borehole instrument can be fixed in the hole of the rock mass.

[0061] Then, the strain sensor 8 is pushed outward by the cylinder 3 9, and the strain sensor 8 is nailed into the surface of the rock mass; the strain sensor 8 is attached to the surface of the rock mass, and the stress on the surface of the rock mass is detected by the strain sensor 8.

[0062] When the motor 5 is in operation, the chain 504, sprocket and other components can drive the drill bit 405 to rotate; at the same time, the cylinder 701 pushes the drill bit 405 outward, and the drill bit 405 is wrapped around the strain sensor 8, and the drill bit 405 drills the rock around the strain sensor 8.

[0063] During the drilling process, the outer periphery of the rock mass to which the strain sensor 8 is installed will be cut, thereby gradually releasing the stress on the rock mass. During this process, the strain sensor 8 continuously detects the stress changes on the surface of the rock mass.

[0064] After drilling is completed, cylinder 701 drives the movable seat 7. The movable seat 7, in conjunction with the magnetic ring 407, moves the linkage cylinder 404 and drill bit 405, allowing the drill bit 405 to be removed from the rock mass and retracted into the in-situ stress measurement borehole apparatus. After testing is completed, cylinder 9 controls the retraction of the telescopic rod 901. The retraction of the telescopic rod 901 removes the strain sensor 8 from the rock surface and retracts it into the in-situ stress measurement borehole apparatus, facilitating its removal and ensuring smooth operation of the testing process.

[0065] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An in-situ stress measurement drilling instrument, characterized in that, The device includes an outer shell (1), a bracket (2), and a drilling assembly (4). The outer shell (1) is fitted over the bracket (2). The drilling assembly (4) includes a linkage sleeve (401), a linkage cylinder (404), and a drill bit (405). The linkage sleeve (401) is rotatably mounted on the bracket (2), and the axis of the linkage sleeve (401) is set along the width direction of the in-situ stress measuring drilling instrument. A transmission wheel (402) is integrally connected to the outer circumference of the linkage sleeve (401). The linkage cylinder (404) is coaxially fitted inside the linkage sleeve (401). The outer circumference of the linkage cylinder (404) and the inner circumference of the linkage sleeve (401) are axially slidably connected by a spline and can maintain synchronous rotation. The drill bit (405) is installed inside the linkage cylinder (404), and part of the drill bit (405) protrudes outside the linkage cylinder (404). It also includes a movable seat (7) and a second cylinder (701). The drilling assembly (4) has a movable seat (7) on the side facing away from the drill bit (405). The movable seat (7) is slidably mounted on the bracket (2) along the coaxial direction of the linkage sleeve (401). The second cylinder (701) is mounted on the bracket (2) and can drive the movable seat (7) to slide. It also includes a motor (5), a coupling (501), a steering gear (502), and a first transmission wheel (503). The motor (5) and the steering gear (502) are both fixedly installed on the bracket (2). The output end of the motor (5) and the input end of the steering gear (502) are connected by the coupling (501). The first transmission wheel (503) is installed on the output end of the steering gear (502). The first transmission wheel (503) and the second transmission wheel (402) are mutually connected. The drill bit (405) has a ring structure; it also includes a cylinder (9) and a strain sensor (8), the strain sensor (8) being located on the inner circumference of the drill bit (405) and being able to extend out of the drill bit (405) through the cylinder (9); The strain sensor (8) has several nails (806) on its outward side, which can be driven into the rock mass; the drill bit (405) is used to drill holes in the rock mass around the strain sensor (8). The movable seat (7) has a through hole (703) which is directly opposite to the inner circumference of the drill bit (405). The cylinder three (9) is installed through the through hole (703). The cylinder three (9) is mounted on the bracket (2) and has a telescopic rod (901) that can extend and retract. The telescopic rod (901) extends into the drill bit (405) along the axial direction of the linkage sleeve (401). The strain sensor (8) is installed on the telescopic rod (901).

2. The in-situ stress measurement drilling instrument according to claim 1, characterized in that, Both ends of the bracket (2) are equipped with support blocks (3) and cylinder one (301). The support blocks (3) are slidably installed along the width direction of the in-situ stress measuring drilling instrument. The cylinder one (301) is used to drive the adjustment cylinder one (301).

3. The in-situ stress measurement drilling instrument according to claim 1, characterized in that, The axis of the output end of the motor (5) is set along the length direction of the in-situ stress measuring drilling instrument, and the axis of the output end of the steering gear (502) is perpendicular to each other; the first transmission wheel (503) and the second transmission wheel (402) are both sprockets and are driven by a chain (504).

4. The in-situ stress measurement drilling instrument according to claim 1, characterized in that, The outer periphery of the linkage sleeve (401) is rotatably mounted on the bracket (2) via bearing one (403), which restricts the axial movement of the linkage sleeve (401); one end of the linkage cylinder (404) faces the movable seat (7), and the linkage cylinder (404) and the movable seat (7) are mounted with bearing two (406), which is a plane bearing used to transmit the axial load of the linkage cylinder (404).

5. The in-situ stress measuring borehole apparatus according to claim 4, characterized in that, The movable seat (7) has a bearing mounting groove (704) on the side facing the linkage cylinder (404), and the second bearing (406) is embedded in the bearing mounting groove (704); a magnetic ring (407) is installed on the side of the movable seat (7) facing away from the linkage cylinder (404), and the magnetic ring (407) is used to magnetically attract the second bearing (406) and the linkage cylinder (404) to move closer to the movable seat (7).

6. The in-situ stress measurement drilling instrument according to claim 1, characterized in that, The strain sensor (8) includes a support base (801) and three sets of rotating rods (803). The support base (801) is fixedly installed on the telescopic rod (901). Three sets of connecting blocks (802) are fixedly installed on the outer periphery of the support base (801). The three sets of rotating rods (803) are rotatably connected to the three sets of connecting blocks (802). The rotation axis of the rotating rod (803) is perpendicular to the telescopic rod (901). The rotating rod (803) has a first end (804) facing away from the cylinder (9) and a second end (805) facing the cylinder (9). The first end (804) of the rotating rod (803) and the mounting nail body (806) are connected. A pre-bending sensing plate (807) is installed between the second ends (805) of adjacent rotating rods (803). The strain sensor (8) is pushed outward in the opposite direction to the support block (3).

7. An in-situ stress measurement method, characterized in that, The in-situ stress measurement borehole apparatus as described in any one of claims 1-6 is used; During the testing process, a hole is first drilled in the rock mass, and then the in-situ stress measuring borehole is placed inside the hole in the rock mass. The support block (3) is pushed outward by cylinder one (301), which can fix the in-situ stress measuring borehole in the hole in the rock mass. The strain sensor (8) is pushed outward by cylinder three (9), and the strain sensor (8) is nailed into the surface of the rock mass. The stress on the surface of the rock mass is detected by the strain sensor (8). The drill bit (405) rotates, and at the same time, the drill bit (405) is pushed outward by cylinder two (701). The drill bit (405) drills the rock mass around the strain sensor (8). During the drilling process, the stress change on the surface of the rock mass is continuously detected by the strain sensor (8).

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