Special multi-stage deformation drilling tool for measuring crustal stress by stress relief method and use method of special multi-stage deformation drilling tool

Abstract

The invention belongs to the technical field of drilling engineering, and discloses a special multi-stage deformation drilling tool for stress relief method crustal stress measurement and a use method.The special multi-stage deformation drilling tool for stress relief method crustal stress measurement comprises a drill bit unit and a connecting unit, and the drill bit unit comprises a first-stage drill bit, a second-stage drill bit, a third-stage drill bit and a reducer pipe; the connecting unit comprises an end rotating pipe, a plurality of connecting rotating pipes, a buckle assembly and a rotating connector. According to the multi-stage deformation drilling tool, through connection and transformation of the first-stage drill bit, the second-stage drill bit, the third-stage drill bit, the end connecting pipe and the connecting rotating pipe which are different in diameter, forming of all large-diameter drill holes and small-diameter drill holes can be completed through one-time drilling, stress relief construction can be conducted without replacing the drill bits, and the overall operation steps are simple. The device is high in adaptability to existing drilling machine equipment and strain gauges, and can be perfectly combined with existing drilling and detecting devices.

Description

Technical Field

[0001] The invention belongs to the technical field of drilling engineering, and in particular relates to a special multi-stage deformation drilling tool for measuring ground stress using a stress relief method and a use method thereof. Background Art

[0002] The measurement of ground stress is very important for geotechnical engineering: 1) Ground stress is the fundamental force that causes deformation and damage of underground or open-pit rock excavation projects, and is one of the most critical factors in rock engineering stability analysis; 2) Ground stress measurement is a necessary prerequisite for determining the properties of engineering rock mass, conducting surrounding rock stability analysis, and realizing scientific rock engineering excavation design and decision-making; 3) Ground stress measurement is also one of the important contents of geomechanics research; 4) Ground stress measurement also has potential application value in earthquake prediction and disaster prevention and mitigation; 5) The development and application of ground stress measurement technology has also promoted the development of related disciplines. In summary, the measurement of ground stress not only provides reliable data support for engineering design and construction, but also provides a scientific basis for geological structure research, earthquake prediction and disaster prevention and mitigation.

[0003] At present, the main methods for measuring geostress include stress recovery method, stress relief method, strain relief method, hydraulic fracturing method, acoustic emission method, X-ray method and gravity method, etc. Among them, stress relief method is the most commonly used and relatively mature geostress measurement method. The essence of this method is to select a measuring point in the rock mass of the measured stress field, install a measuring element at the measuring point, and then cut a groove or make a hole around the installed measuring element to separate the rock where the measuring element is installed from the surrounding rock mass, that is, to free this part of the rock from the measured stress field; at this time, the rock at the measuring point will produce elastic recovery deformation due to the disappearance of external force; by measuring this deformation, the magnitude and direction of the geostress can be calculated. When using this method to measure ground stress, first, a hole with a depth of about 20m and a diameter of 130mm needs to be drilled in the rock formation; then the drill is withdrawn and the drill bit is replaced with a small drill bit with a diameter of 36mm, and a small hole with a depth of 350mm is drilled at the bottom of the original hole; the drill is withdrawn again and replaced with a coring drill bit with a diameter of 130mm, and the stress gauge (hollow inclusion strain gauge) is installed in the small hole, and the external wire of the stress gauge is passed through each drill rod in turn; finally, a stress relief experiment is carried out, and the changes of the stress gauge are monitored in real time during the core setting process, and then the corresponding ground stress is calculated. It can be seen from this that this method requires multiple withdrawals and replacements of the drill bit during the specific implementation process, and the steps are cumbersome and time-consuming and laborious; at the same time, the external wire of the stress gauge needs to pass through each drill rod in turn, and the operation is also very complicated, making the connection between the drill rods very time-consuming. Therefore, a drilling tool that does not require repeated withdrawals, replacement of drill bits, and quick installation of stress gauges is needed to improve the convenience of using the stress relief method. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a special multi-stage deformable drilling tool for measuring ground stress by a stress relief method and a use method thereof.

[0005] In order to achieve the above-mentioned object, the present invention adopts the following technical scheme: a special multi-stage deformable drilling tool for measuring ground stress by stress relief method, comprising a drill unit and a connection unit, wherein the drill unit comprises a primary drill bit, a secondary drill bit, a tertiary drill bit and a reducer; the connection unit comprises an end rotating tube, a plurality of connecting rotating tubes, a buckle assembly and a rotating joint; The first-stage drill bit comprises a first-stage drill bit tube body which is hollow inside, a first-stage drill bit track groove and a pin hole are arranged in the first-stage drill bit tube body along the axial direction, and the tail end of the first-stage drill bit tube body is connected to the reducer; The secondary drill bit comprises a secondary drill bit tube body with a hollow interior, the secondary drill bit tube body is coaxially arranged in the primary drill bit tube body, a secondary drill bit spring pin is arranged on the secondary drill bit tube body, the secondary drill bit spring pin is matched with the pin hole to achieve connection, and can be slidably arranged in the primary drill bit track groove, a secondary drill bit track groove and a control component are axially arranged in the secondary drill bit tube body, and the control component is connected to the secondary drill bit spring pin; The three-stage drill bit comprises a three-stage drill bit tube body with a hollow interior, the three-stage drill bit tube body is coaxially arranged in the two-stage drill bit tube body, and a first wing spring pin is symmetrically arranged outside the three-stage drill bit tube body, and the first wing spring pin is slidably arranged in the two-stage drill bit track groove; The tertiary drill bit tube body is connected to the end rotating tube by a thread, and the end rotating tube is also connected to the reducer by a thread. The tail end of the end rotating tube is connected to several connecting rotating tubes in sequence. A snap assembly is provided in the tertiary drill bit tube body, the end rotating tube and all the connecting rotating tubes. The rotating joint is connected to the last connecting rotating tube and the snap assembly. Rotating the rotating joint drives the tertiary drill bit to move back and forth in the secondary drill bit.

[0006] Furthermore, the outer diameter of the first-stage drill bit tube body is 130 mm, the outer diameter of the second-stage drill bit tube body is 100 mm, and the outer diameter of the third-stage drill bit tube body is 36 mm; A plurality of first-level drill bit tooth platforms are distributed along the circumferential direction on the front end surface of the first-level drill bit tube body, and a first-level drill bit pick is provided on each first-level drill bit tooth platform, and the outer diameter of the first-level drill bit pick is at least 5 mm greater than the outer diameter of the first-level drill bit tube body; A plurality of secondary drill bit tooth platforms are distributed along the circumferential direction on the front end surface of the secondary drill bit tube body, and a secondary drill bit pick is arranged on each secondary drill bit tooth platform, and the outer diameter of the secondary drill bit pick is smaller than the outer diameter of the secondary drill bit tooth platform; A conical drill bit is provided at the front end of the three-stage drill bit tube body, and four top water outlet holes are provided on the conical drill bit, one of which is located at the top of the conical drill bit, and the other three are distributed at 120 degrees on the circumferential surface of the conical drill bit, and the three top water outlet holes are coplanar, and a plurality of outer water outlet holes are evenly opened on the three-stage drill bit tube body along the circumferential direction; The number of the first-level drill track grooves is 2, which are symmetrically arranged in the first-level drill tube body, and the number of the pin holes is 2, which are respectively located at the front end of each drill track groove; The number of the secondary drill bit spring pins is 2, the number of the secondary drill bit tracks is 2, and the number of the first wing spring pins is 2; Each of the first wing spring pins is connected to a first compression spring chamber, and the first compression spring chamber is located in the third-stage drill bit tube body.

[0007] Further, the end rotating tube comprises a first rotating tube, a first bearing and a tail tube, the tail end of the first rotating tube is rotatably connected to the tail tube through the first bearing, the tail end of the third-stage drill bit body is threadedly connected to the front end of the first rotating tube and placed together in the second-stage drill bit, the front end of the tail tube is connected to the reducer, and the tail end of the tail tube is sequentially connected to a plurality of connecting rotating tubes; The connecting rotating tube comprises an outer tube body, a second bearing and a second rotating tube; the second rotating tube is located inside the outer tube body, and the two are coaxial, and both ends of the second rotating tube are respectively connected to the outer tube body for rotation via the second bearing; the outer tube bodies and second rotating tubes of adjacent connecting rotating tubes are respectively connected via threads, the first second rotating tube is connected to the first rotating tube via threads, and the first outer tube body is connected to the tail tube via threads; By rotating the rotating joint clockwise or counterclockwise, all the second rotating tubes and the first rotating tube are driven to rotate clockwise or counterclockwise, thereby driving the tertiary drill bit to move forward or backward in the secondary drill bit.

[0008] Furthermore, the front end of the tail pipe is provided with a tail pipe internal thread for connecting with the reducer, and the tail end of the tail pipe is provided with a tail pipe external thread for connecting with the second rotating pipe connected to the first rotating pipe; The tail end of the three-stage drill bit tube body is provided with a three-stage drill bit external thread, the front end of the first rotating tube is provided with a first internal thread for connecting with the three-stage drill bit external thread, and the front end of the first rotating tube is symmetrically provided with two notches, and the tail end of the first rotating tube is provided with a first external thread; two first clamping holes are symmetrically provided at the first external thread; The front end of the external tube body of each connecting rotating tube is provided with an external tube body internal thread, the external tube body internal thread of the first connecting rotating tube is used to connect with the external tube body thread of the tail tube, and the tail end of the external tube body is provided with an external tube body external thread, which is used to connect with the external tube body internal thread of the adjacent connecting rotating tube; each second rotating tube is provided with a second internal thread at the front end and a second external thread at the tail end; Two first clamping grooves are symmetrically arranged at the second internal thread of the second rotating tube, and the depth of the two first clamping grooves is 1 / 2 of the thickness of the second rotating tube; two second clamping holes are symmetrically arranged at the second external thread of the second rotating tube; The two first slots on the first second rotating tube connected to the rotating tube correspond to the two first holes on the first rotating tube in position and size, and the two first slots on the other two adjacent second rotating tubes correspond to the two second holes in position and size.

[0009] Furthermore, the buckle assembly includes a double buckle assembly and a single buckle assembly. The double buckle assembly is provided in the first rotating tube, and the single buckle assembly is provided in each second rotating tube. Adjacent single buckle assemblies are buckled and connected, and each single buckle assembly is buckled with the second rotating tube outside it and the connection of the next second rotating tube to connect the adjacent second rotating tubes; the first single buckle assembly is buckled and connected with the double buckle assembly, one end of the double buckle assembly is buckled and connected with the third-level drill bit tube body, and the other end is buckled with the first rotating tube and the connection of the first second rotating tube, so that the third-level drill bit tube body, the end rotating tube and the first connecting rotating tube are connected together; The double buckle assembly includes two first buckles, a first steel wire rope and a first double-wing spring pin, the two first buckles are connected to two pull rings in the tail end of the third-level drill bit tube body, the bottoms of the two first buckles are respectively connected to the first double-wing spring pin through the first steel wire rope, the first double-wing spring pin and the first steel wire rope pass through the inside of the first rotating tube, and the first double-wing spring pin is connected to the two first clamping holes on the first rotating tube; The single buckle assembly includes a second buckle, a second steel wire rope and a second double-wing spring pin, and the bottom of the second buckle is connected to the second double-wing spring pin through the second steel wire rope; the second buckle is used to connect with the first double-wing spring pin in the adjacent double buckle assembly or the second double-wing spring pin in the single buckle assembly; The first double-wing spring pin and the second double-wing spring pin have the same structure, both comprising a second compression spring chamber, two second wing spring pins, an upper hanging ring and a lower hanging ring. A second wing spring pin is respectively provided on the left and right sides of the second compression spring chamber, and an upper hanging ring and a lower hanging ring are respectively provided at the upper and lower ends of the second compression spring chamber. The upper hanging ring is used to connect the first steel wire rope or the second steel wire rope, and the lower hanging ring is used to connect with the first buckle or the second buckle.

[0010] Furthermore, the control component includes a driving shaft, a connecting shaft, a fixed platform, a slide rail, a limit spring pin, a connecting rod, a spring platform and a spring. A cavity connected to the secondary drill bit track groove is provided in front of the secondary drill bit track groove, and the cavity is also connected to the pin hole. The driving shaft is placed in the secondary drill bit track groove, and two parallel connecting plates are provided at the front end of the driving shaft. A fixed platform is provided between the two connecting plates. The connecting plates and the fixed platform are both placed in the cavity. An inclined slide rail is provided on the fixed platform. A connecting shaft is installed on the two connecting plates. The connecting shaft is slidably placed in the slide rail. A limit spring pin is also provided in the slide rail. The outside of the fixed platform A connecting rod is provided on the side, and a spring platform is provided on the connecting rod. The spring platform is fixed on the inner wall of the cavity, and the end of the connecting rod is fixed to the secondary drill spring pin. A spring is provided on the outside of the connecting rod between the spring platform and the secondary drill spring pin; when the active shaft is subjected to force, the active shaft drives the connecting plate to move forward, thereby driving the connecting shaft to move upward along the slide rail. At this time, the fixed platform together with the connecting rod moves to the side away from the secondary drill spring pin, thereby driving the secondary drill spring pin to compress the spring and retract it along the pin hole to one side of the cavity. When the connecting shaft moves to above the limit spring pin, the limit spring pin pops out to limit it.

[0011] Further, the rotary joint includes a square end and a joint tube body, the square end is a solid structure, a hollow joint tube body is provided at the front end of the square end, a third internal thread is provided at the front end of the joint tube body, and the second external thread of the last second rotary tube is matched, and two symmetrically arranged second clamping grooves are provided at the third internal thread, and the two second clamping grooves correspond to the positions and sizes of the two second clamping holes of the second rotary tube; The rotating joint is rotated clockwise to drive all the second rotating tubes and the first rotating tube to rotate clockwise, and the two first wing spring pins outside the third-level drill bit tube body are controlled to move forward along the second-level drill bit track groove through the thread of the tail end of the third-level drill bit tube body and the first rotating tube, thereby driving the control component to operate, control the two spring pins of the second-level drill bit tube body to retract, disengage from the pin holes of the first-level drill bit tube body, and place them in the first-level drill bit track groove; Rotate the rotary joint counterclockwise to drive all the connecting rotary tubes and the end rotary tube to rotate counterclockwise, so that the end rotary tube is separated from the tertiary drill bit tube body. After disassembling the rotary joint, pull the single clip assembly in the last connecting rotary tube backward, and pull all the single clip assemblies, double clip assemblies and the tertiary drill bit out through the end rotary tube and the connecting rotary tube.

[0012] The present invention also provides a method for using a special multi-stage deformable drilling tool for measuring ground stress using a stress relief method, which is implemented using the special multi-stage deformable drilling tool for measuring ground stress using the stress relief method, and specifically includes the following steps: S1. Use a drilling rig and a φ130mm drill bit to drill a hole 1m deep at the measurement location; S2. Drill bit assembly: remove the φ130mm drill bit and drill rod, assemble the first-level drill bit, second-level drill bit, third-level drill bit and end rotating tube together and put them into the drill hole, and adjust the position of the third-level drill bit by rotating the end rotating tube so that its front end protrudes from the front ends of the first-level drill bit and the second-level drill bit; S3, Drilling tool assembly and drilling of large diameter boreholes: Install a double clip assembly in the third-stage drill bit and the end rotating tube, and use a drilling rig to connect the tail end of the end rotating tube to the first connecting rotating tube, clamp the double clip assembly to the connecting rotating tube, and then connect the water whip to the tail end of the first connecting rotating tube to drill; Then remove the water whip, install a single clip assembly at the tail end of the double clip assembly, and then use the drilling rig to connect the second connecting rotating tube at the tail end of the first connecting rotating tube. After the connection is completed, the single clip assembly is connected to the second connecting rotating tube, and the water whip is installed to continue drilling; this cycle is repeated until the drilling depth reaches the designed depth, and the drilling of the large-diameter borehole is completed; S4. Drill bit change and drilling of small diameter holes: install the rotary joint at the tail end of the last connecting rotary tube, then withdraw the drill as a whole by 400mm, and use a wrench to rotate the rotary joint clockwise, so that the second rotary tubes in all the connecting rotary tubes and the first rotary tube in the end rotary tube rotate clockwise. At this time, the third-level drill bit tube body will push the first wing spring pin of the third-level drill bit tube body to move forward along the inside of the second-level drill bit tube body to the front end of the second-level drill bit track groove under the joint action of its first wing spring pin and thread. The two first wing spring pins contact with the control component and trigger its action, so that the two second-level drill bit spring pins outside the second-level drill bit tube body are retracted, disengaged from the two pin holes on the first-level drill bit tube body, and placed in the first-level drill bit track groove; Remove the rotary joint, reinstall the water whip, and make the front end of the three-stage drill bit contact the bottom of the hole for drilling. The drilling depth of the three-stage drill bit is 35cm; S5. Recovery of the third-stage drill bit: After the small-diameter hole is drilled, the water whip is removed and the rotary joint is connected. The rotary joint is rotated counterclockwise. At this time, the third-stage drill bit will move backward along the second-stage drill bit track groove. If the hole is drilled upward, the second-stage drill bit will also move downward under the action of its own weight; it keeps rotating until the first rotary tube is disengaged from the thread of the third-stage drill bit. At this time, the first wing spring pin wing of the third-stage drill bit is located in the two notches at the front end of the first rotary tube; at this time, the last second double-wing spring pin connected to the rotary tube is continuously pulled backward, so that all the single-buckle components and the double-buckle components move backward together, so that the third-stage drill bit passes through the first rotary tube and all the second rotary tubes in turn until the third-stage drill bit is completely pulled out; S6. Install the stress gauge: inject adhesive into the inner cavity of the stress gauge, install the hollow inclusion strain gauge through all the second rotating tubes and the first rotating tube in turn to the predetermined position in the small-diameter borehole after drilling, and then squeeze the adhesive from the inner cavity of the stress gauge into the gap between the stress gauge and the small-diameter borehole, and then wait for the adhesive inside the strain gauge to completely solidify, and firmly bond the stress gauge to the wall of the small-diameter borehole; S7, stress relief drilling: Since the two spring pins of the secondary drill bit have retracted, after installing the water whip and drilling, as the primary drill bit continues to advance, the rock entering the interior will push the secondary drill bit to move backward along the primary drill bit track groove until the stress relief experiment is completed. During the whole process, the strain value monitored by the stress meter is recorded; S8. Drill withdrawal: According to the normal drill withdrawal method, the connecting rotary tube, the first-stage drill bit, the second-stage drill bit and the third-stage drill bit are removed in sequence.

[0013] Furthermore, in step S2, the assembly of the first-stage drill bit, the second-stage drill bit and the third-stage drill bit is specifically as follows: firstly, the reducer is installed on the tail tube of the end rotating tube, and then the tail end of the third-stage drill bit body is connected to the first rotating tube of the end rotating tube through threads; Before connection, first connect the two pull rings below the tertiary drill bit tube body to the two first buckles in the double buckle assembly, and connect a first steel wire rope to each of the two first buckles. The two first steel wire ropes are respectively connected to the upper hanging rings of the first double-wing spring pin, and the first double-wing spring pin and the first steel wire rope are respectively passed through the end rotating tube. Then, the secondary drill bit tube body is sleeved on the outside of the tertiary drill bit tube body, and the two first wing spring pins on the tertiary drill bit tube body are respectively placed at the bottom of the secondary drill bit rail groove on the inner side of the secondary drill bit tube body. Then, the primary drill bit is sleeved on the outside of the secondary drill bit, so that the spring pin outside the secondary drill bit tube body is located in the pin hole of the primary drill bit tube body. After completion, the position of the tertiary drill bit is adjusted by rotating the first rotating tube of the end rotating tube clockwise so that the top of the conical drill bit of the tertiary drill bit exceeds the front end of the primary drill bit and the secondary drill bit by 5 mm.

[0014] Furthermore, the diameter of the large-diameter drill hole is 130 mm, and the diameter of the small-diameter drill hole is 36 mm.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The multi-stage deformable drilling tool of the present invention can complete the formation of all large-diameter and small-diameter holes by drilling once through the connection and transformation between the first-stage drill bit, the second-stage drill bit, the third-stage drill bit, the end connecting tube, and the connecting rotating tube of different diameters, and can perform stress relief construction without changing the drill bit, and the overall operation steps are simple; (2) When the present invention is used to measure ground stress using the stress relief method, the strain gauge is easy to install. It is not necessary to pass its external wire through each drill pipe in turn. Instead, the strain gauge can be installed in place by directly connecting the rotating tube and the end rotating tube through the installation rod. The construction is simple and convenient. (3) The structural design of the end connecting pipe and the connecting rotating pipe of the multi-stage deformable drill tool of the present invention makes the drill tool highly adaptable to existing drilling equipment and strain gauges, and can be perfectly combined with existing drilling and detection devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the external structure of a special multi-stage deformable drilling tool for measuring ground stress by the stress relief method of the present invention; Figure 2 This is a schematic diagram of the front end structure of the drill unit of the present invention; Figure 3 This is a schematic diagram of the rear end structure of the drill unit of the present invention; Figure 4 This is one of the structural schematic diagrams of the primary drill bit and the reducer connection of the present invention; Figure 5 This is the second structural schematic diagram of the primary drill bit and the reducer connection of the present invention; Figure 6 This is one of the schematic diagrams of the secondary drill bit structure of the present invention; Figure 7 This is the second schematic diagram of the secondary drill bit structure of the present invention; Figure 8 This is one of the schematic diagrams of the connection structure between the control assembly and the secondary drill spring pin of the present invention; Fig. 9 It is a schematic diagram of the connection structure of the control assembly and the secondary drill spring pin in the secondary drill, and the secondary drill spring pin is in a pop-up state; Fig.10 It is a schematic diagram of the connection structure of the control assembly and the secondary drill spring pin in the secondary drill, and the secondary drill spring pin is in a retracted state; Fig.11 It is a schematic diagram of the front end structure of the three-stage drill bit of the present invention; Fig.12 It is a schematic diagram of the rear end structure of the three-stage drill bit of the present invention; Fig.13 It is a schematic diagram of the front end structure of the end rotating tube of the present invention; Fig.14 It is a schematic diagram of the rear end structure of the end rotating tube of the present invention; Fig.15 This is a schematic diagram of the structure of the rotary tube connected to the present invention; Fig.16 is a schematic structural diagram of the second connecting pipe of the present invention; Fig.17 It is a schematic diagram of the connection structure of the double buckle assembly and the single buckle assembly of the present invention; Fig.18 It is a schematic structural diagram of a double-wing spring pin of the present invention; Fig.19 It is a structural schematic diagram of the rotary joint of the present invention.

[0017] Markings in the figure: 1, first-stage drill bit; 101, first-stage drill bit tube body; 102, first-stage drill bit track groove; 103, pin hole; 104, first-stage drill bit tooth table; 105, first-stage drill bit pick; 2. Secondary drill bit; 201. Secondary drill bit tube body; 202. Secondary drill bit rail groove; 203. Control assembly; 2031. Active shaft; 2032. Connecting shaft; 2033. Fixed platform; 2034. Slide rail; 2035. Limit spring pin; 2036. Connecting rod; 2037. Spring platform; 2038. Spring; 2039. Connecting plate; 204, spring pin of secondary drill bit; 205, tooth stand of secondary drill bit; 206, pick tooth of secondary drill bit; 3. Three-stage drill bit; 301. Three-stage drill bit tube body; 302. First wing spring pin; 303. First compression spring chamber; 304. Conical drill bit; 305. Top water outlet hole; 306. External water outlet hole; 307. Pull ring; 308. External thread of three-stage drill bit; 4. Reducer; 5. End rotating tube; 501. First rotating tube; 5011. First internal thread; 5012. First external thread; 5013. Notch; 5014. First clamping hole; 502. First bearing; 503. Tail tube; 5031. Tail tube internal thread; 5032. Tail tube external thread; 6. Connecting rotating tube; 601. External tube body; 6011. External tube body inner thread; 6012. External tube body outer thread; 602. Second bearing; 603. Second rotating tube; 6031. Second internal thread; 6032. Second external thread; 6033. First clamping groove; 6034. Second clamping hole; 7. Double buckle assembly; 701. First buckle; 702. First steel wire rope; 703. First double-wing spring pin; 8. Single buckle assembly; 801. Second buckle; 802. Second steel wire rope; 803. Second double-wing spring pin; 9. Second compression spring chamber; 10. Second wing spring pin; 11. Upper hanging ring; 12. Lower hanging ring; 13. Rotary joint; 1301. Square end; 1302. Joint body; 1303. Third internal thread; 1304. Second slot. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below.

[0019] Embodiment 1

[0020] Reference Figure 1-Figure 19 A special multi-stage deformable drilling tool for measuring ground stress using a stress relief method includes a drill unit and a connection unit. The drill unit includes a first-stage drill bit 1, a second-stage drill bit 2, a third-stage drill bit 3 and a reducer 4; the connection unit includes an end rotating tube 5, a plurality of connecting rotating tubes 6, a buckle assembly and a rotating joint 13; Reference Figure 4 and Figure 5 The first-level drill bit 1 comprises a first-level drill bit tube body 101 which is hollow inside, a first-level drill bit track groove 102 and a pin hole 103 are axially arranged inside the first-level drill bit tube body 101, and the tail end of the first-level drill bit tube body 101 is connected to the reducer 4; Reference Figure 6 and Figure 7 The secondary drill bit 2 comprises a secondary drill bit tube body 201 which is hollow inside. The secondary drill bit tube body 201 is coaxially arranged in the primary drill bit tube body 101. A secondary drill bit spring pin 204 is arranged on the secondary drill bit tube body 201. The secondary drill bit spring pin 204 is matched with the pin hole 103 to achieve connection and is slidably arranged in the primary drill bit track groove 102. A secondary drill bit track groove 202 and a control component 203 are axially arranged in the secondary drill bit tube body 201. The control component 203 is connected to the secondary drill bit spring pin 204. Reference Figure 11-Figure 12 The tertiary drill bit 3 comprises a tertiary drill bit tube body 301 which is hollow inside. The tertiary drill bit tube body 301 is coaxially arranged in the secondary drill bit tube body 201. A first wing spring pin 302 is symmetrically arranged outside the tertiary drill bit tube body 301. The first wing spring pin 302 is slidably arranged in the secondary drill bit rail groove 202. The tertiary drill bit tube body 301 is connected to the end rotating tube 5 by a thread, and the end rotating tube 5 is also connected to the reducer 4 by a thread. The tail end of the end rotating tube 5 is connected to several connecting rotating tubes 6 in sequence. A snap assembly is provided in the tertiary drill bit tube body 301, the end rotating tube 5, and all the connecting rotating tubes 6. The rotating joint 13 is connected to the last connecting rotating tube 6 and the snap assembly. Rotating the rotating joint 13 drives the tertiary drill bit 3 to move back and forth in the secondary drill bit 2.

[0021] The outer diameter of the first-stage drill bit tube body 101 is 130 mm, the outer diameter of the second-stage drill bit tube body 201 is 100 mm, and the outer diameter of the third-stage drill bit tube body 301 is 36 mm; Reference Figure 2-Figure 5A plurality of first-level drill bit tooth platforms 104 are distributed along the circumferential direction on the front end surface of the first-level drill bit tube body 101, and a first-level drill bit pick 105 is provided on each first-level drill bit tooth platform 104, and the outer diameter of the first-level drill bit pick 105 is at least 5 mm greater than the outer diameter of the first-level drill bit tube body 101; Reference Figure 2 , Figure 6 and Figure 7 A plurality of secondary drill bit tooth platforms 205 are distributed along the circumferential direction on the front end surface of the secondary drill bit tube body 201, and a secondary drill bit pick 206 is provided on each secondary drill bit tooth platform 205, and the outer diameter of the secondary drill bit pick 206 is smaller than the outer diameter of the secondary drill bit tooth platform 205; Reference Fig.11 and Fig.12 The front end of the three-stage drill bit tube body 301 is provided with a conical drill bit 304, and four top water outlet holes 305 are provided on the conical drill bit 304, one of the top water outlet holes 305 is located at the top of the conical drill bit 304, and the other three are distributed on the circumferential surface of the conical drill bit 304 at 120 degrees, and the three top water outlet holes 305 are coplanar, and a plurality of outer water outlet holes 306 are evenly opened on the three-stage drill bit tube body 301 along the circumferential direction; The number of the first-level drill track grooves 102 is 2, which are symmetrically arranged in the first-level drill tube body 101, and the number of the pin holes 103 is 2, which are respectively located at the front end of each drill track groove; The number of the secondary drill spring pins 204 is 2, the number of the secondary drill 2 tracks is 2, and the number of the first wing spring pins 302 is 2; Each of the first wing spring pins 302 is connected to a first compression spring chamber 303 , and the first compression spring chamber 303 is located in the tertiary drill bit tube body 301 .

[0022] Reference Fig.13 and Fig.14 The end rotating tube 5 includes a first rotating tube 501, a first bearing 502 and a tail tube 503. The tail end of the first rotating tube 501 is rotatably connected to the tail tube 503 through the first bearing 502. The tail end of the tertiary drill bit body 301 is threadedly connected to the front end of the first rotating tube 501 and placed together in the secondary drill bit 2. The front end of the tail tube 503 is connected to the reducer 4. The tail end of the tail tube 503 is sequentially connected to a plurality of connecting rotating tubes 6. Reference Fig.15 and Fig.16The connecting rotating tube 6 includes an outer tube body 601, a second bearing 602 and a second rotating tube 603; the second rotating tube 603 is located inside the outer tube body 601, and the two are coaxial, and both ends of the second rotating tube 603 are respectively rotatably connected to the outer tube body 601 through the second bearing 602; the outer tube bodies 601 and the second rotating tubes 603 of the adjacent connecting rotating tubes 6 are respectively connected by threads, the first second rotating tube 603 is connected to the first rotating tube 501 by threads, and the first outer tube body 601 is connected to the tail tube 503 by threads; By rotating the rotating joint 13 clockwise or counterclockwise, all the second rotating tubes 603 and the first rotating tube 501 are driven to rotate clockwise or counterclockwise, thereby driving the tertiary drill bit 3 to move forward or backward in the secondary drill bit 2.

[0023] Reference Fig.13 and Fig.14 The front end of the tail pipe 503 is provided with a tail pipe internal thread 5031 for connecting with the reducer 4, and the tail end of the tail pipe 503 is provided with a tail pipe external thread 5032 for connecting with the second rotating tube 603 connected to the first rotating tube 6; The tail end of the three-stage drill bit tube body 301 is provided with a three-stage drill bit external thread 308, the front end of the first rotating tube 501 is provided with a first internal thread 5011 for connecting with the three-stage drill bit external thread 308, and the front end of the first rotating tube 501 is symmetrically provided with two notches 5013, and the tail end of the first rotating tube 501 is provided with a first external thread 5012; two first clamping holes 5014 are symmetrically arranged at the first external thread 5012.

[0024] Reference Fig.15 and Fig.16 , each of the external tube bodies 601 connected to the rotating tube 6 has an external tube body internal thread 6011 at the front end, the external tube body internal thread 6011 of the first connected rotating tube 6 is used to connect with the tail tube external thread 5032, and the external tube body 601 has an external tube body external thread 6012 at the tail end, which is used to connect with the external tube body internal thread 6011 of the adjacent connected rotating tube 6; each second rotating tube 603 has a second internal thread 6031 at the front end and a second external thread 6032 at the tail end; Two first clamping grooves 6033 are symmetrically arranged at the second internal thread 6031 of the second rotating tube 603. The depth of the two first clamping grooves 6033 is 1 / 2 of the thickness of the second rotating tube 603 and does not penetrate the tube body of the second rotating tube 603. Two second clamping holes 6034 are symmetrically arranged at the second external thread 6032 of the second rotating tube 603. The second clamping holes 6034 penetrate the tube body of the second rotating tube 603. The two first slots 6033 on the first second rotating tube 603 connected to the rotating tube 6 correspond to the two first holes 5014 on the first rotating tube 501 in position and size, and the two first slots 6033 on the other two adjacent second rotating tubes 603 correspond to the two second holes 6034 in position and size.

[0025] Reference Fig.17 The buckle assembly includes a double buckle assembly 7 and a single buckle assembly 8. The double buckle assembly 7 is provided in the first rotating tube 501, and a single buckle assembly 8 is provided in each second rotating tube 603. Adjacent single buckle assemblies 8 are buckled and connected, and each single buckle assembly 8 is buckled with the second rotating tube 603 outside it and the connection of the next second rotating tube 603 to connect the adjacent second rotating tubes 603; the first single buckle assembly 8 is buckled and connected with the double buckle assembly 7, one end of the double buckle assembly 7 is buckled and connected with the tertiary drill bit tube body 301, and the other end is buckled with the first rotating tube 501 and the connection between the first second rotating tube 603, so as to connect the tertiary drill bit tube body 301, the end rotating tube 5 and the first connecting rotating tube 6 together; The double buckle assembly 7 includes two first buckles 701, a first steel wire rope 702 and a first double-wing spring pin 703. The two first buckles 701 are connected to the two pull rings 307 in the tail end of the third-level drill bit tube 301. The bottoms of the two first buckles 701 are connected to the first double-wing spring pin 703 through the first steel wire rope 702 respectively. The first double-wing spring pin 703 and the first steel wire rope 702 pass through the inside of the first rotating tube 501. The first double-wing spring pin 703 is connected to the two first clamping holes 5014 on the first rotating tube 501. The single buckle assembly 8 includes a second buckle 801, a second steel wire rope 802 and a second double-wing spring pin 803. The bottom of the second buckle 801 is connected to the second double-wing spring pin 803 through the second steel wire rope 802. The second buckle 801 is used to connect with the first double-wing spring pin 703 in the adjacent double buckle assembly 7 or the second double-wing spring pin 803 in the single buckle assembly 8. Reference Fig.18 The first double-wing spring pin 703 and the second double-wing spring pin 803 have the same structure, both including a second compression spring chamber 9, two second wing spring pins 10, an upper hanging ring 11 and a lower hanging ring 12. A second wing spring pin 10 is respectively provided on the left and right sides of the second compression spring chamber 9, and an upper hanging ring 11 and a lower hanging ring 12 are respectively provided on the upper and lower ends of the second compression spring chamber 9. The upper hanging ring 11 is used to connect the first steel wire rope 702 or the second steel wire rope 802, and the lower hanging ring 12 is used to connect with the first buckle 701 or the second buckle 801.

[0026] The first buckle 701 and the second buckle 801 are O-shaped key buckles.

[0027] Reference Figure 8-Figure 10 The control assembly 203 includes a driving shaft 2031, a connecting shaft 2032, a fixed platform 2033, a slide rail 2034, a limit spring pin 2035, a connecting rod 2036, a spring platform 2037 and a spring 2038. A cavity connected to the secondary drill bit track groove 202 is provided in front of the secondary drill bit track groove 202, and the cavity is also connected to the pin hole 103. The driving shaft 2031 is placed in the secondary drill bit track groove 202, and two parallel connecting plates 2039 are provided at the front end of the driving shaft 2031. A fixed platform 2033 is provided between the two connecting plates 2039. The connecting plates 2039 and the fixed platform 2033 are both placed in the cavity. An inclined slide rail 2034 is provided on the fixed platform 2033. The two connecting plates 2039 are equipped with a connecting shaft 2032. The connecting shaft 2032 is slidably placed in the slide rail 2034. A limit spring pin 2035 is also provided in the slide rail 2034. The fixed platform 2033 is provided with an inclined slide rail 2034. A connecting rod 2036 is provided on the outside of the fixed platform 2033, and a spring platform 2037 is provided on the connecting rod 2036. The spring platform 2037 is fixed on the inner wall of the cavity, and the end of the connecting rod 2036 is fixed to the secondary drill spring pin 204. A spring 2038 is provided on the outside of the connecting rod 2036 between the spring platform 2037 and the secondary drill spring pin 204; when the active shaft 2031 is subjected to force, the active shaft 2031 drives the connecting plate 2039 to move forward, thereby driving the connecting shaft 2032 to move upward along the slide rail 2034. At this time, the fixed platform 2033 moves together with the connecting rod 2036 to the side away from the secondary drill spring pin 204, thereby driving the secondary drill spring pin 204 to compress the spring 2038 and retract it to one side of the cavity along the pin hole 103. When the connecting shaft 2032 moves to above the limiting spring pin 2035, the limiting spring pin 2035 pops out to limit it.

[0028] Reference Fig.19 The rotary joint 13 includes a square end 1301 and a joint body 1302. The square end 1301 is a solid structure. A hollow joint body 1302 is provided at the front end of the square end 1301. A third internal thread 1303 is provided at the front end of the joint body 1302 to match the second external thread 6032 of the last second rotary tube 603. Two symmetrically arranged second clamping grooves 1304 are provided at the third internal thread 1303. The two second clamping grooves 1304 correspond to the positions and sizes of the two second clamping holes 6034 of the second rotary tube 603. The rotating joint 13 is rotated clockwise to drive all the second rotating tubes 603 and the first rotating tube 501 to rotate clockwise, and the two first wing spring pins 302 outside the third-level drill bit tube 301 are controlled to move forward along the second-level drill bit track groove 202 through the thread of the tail end of the third-level drill bit tube 301 and the first rotating tube 501, thereby driving the control component 203 to operate, control the two second-level drill bit spring pins 204 of the second-level drill bit tube 201 to retract, disengage from the pin hole 103 of the first-level drill bit tube 101, and place them in the first-level drill bit track groove 102; Rotate the rotary joint 13 counterclockwise to drive all the connecting rotating tubes 6 and the end rotating tube 5 to rotate counterclockwise, so that the end rotating tube 5 is separated from the tertiary drill bit tube body 301. After disassembling the rotary joint 13, pull the single snap assembly 8 in the last connecting rotating tube 6 backward to completely pull out all the single snap assemblies 8, double snap assemblies 7 and the tertiary drill bit 3 through the end rotating tube 5 and the connecting rotating tube 6.

[0029] Embodiment 2

[0030] This embodiment is described by taking a 130 mm large diameter borehole drilling 20 m and a 36 mm small diameter borehole drilling 35 cm as examples.

[0031] Reference Figure 1-Figure 19 The method for using the special multi-stage deformable drilling tool for measuring ground stress by stress relief method is implemented by using the special multi-stage deformable drilling tool for measuring ground stress by stress relief method described in the first embodiment, and specifically comprises the following steps: S1. Use a drilling rig and a φ130mm drill bit to drill a hole 1m deep at the measurement location; S2, drill bit assembly: remove the φ130mm drill bit and drill rod, and assemble the first-level drill bit 1, the second-level drill bit 2, the third-level drill bit 3 and the end rotating tube 5 together and put them into the drill hole, and adjust the position of the third-level drill bit 3 by rotating the end rotating tube 5 so that its front end protrudes 5mm from the front ends of the first-level drill bit 1 and the second-level drill bit 2; In step S2, the assembly of the primary drill bit 1, the secondary drill bit 2 and the tertiary drill bit 3 is specifically as follows: first, the reducer is installed on the tail tube 503 of the end rotating tube 5, and then the tail end of the tertiary drill bit body 301 is connected to the first rotating tube 501 of the end rotating tube 5 by threading; Before connection, first connect the two pull rings 307 below the tertiary drill bit tube body 301 with the two first buckles 701 of the double buckle assembly 7, and connect a first steel wire rope 702 to each of the two first buckles 701. The two first steel wire ropes 702 are respectively connected to the upper hanging ring 11 of the first double-wing spring pin 703, and the first double-wing spring pin 703 and the first steel wire rope 702 are respectively passed through the end rotating tube 5 (the length of the first steel wire rope 702 should be sufficient to allow the first double-wing spring pin 703 to be exposed outside the tail end of the end rotating tube 5 by not less than 400 mm after the tertiary drill bit tube body 301 is connected to the end rotating tube 5). Then, connect the secondary The drill bit tube body 201 is sleeved on the outside of the tertiary drill bit tube body 301, and the two first wing spring pins 302 on the tertiary drill bit tube body 301 are respectively placed at the bottom of the secondary drill bit rail groove 202 inside the secondary drill bit tube body 201, and then the primary drill bit 1 is sleeved on the outside of the secondary drill bit 2, so that the secondary drill bit spring pin 204 outside the secondary drill bit tube body 201 is located in the pin hole 103 of the primary drill bit tube body 101. After completion, the position of the tertiary drill bit 3 is adjusted by rotating the first rotating tube 501 of the end rotating tube 5 clockwise, so that the top end of the conical drill bit 304 of the tertiary drill bit 3 exceeds the front end of the primary drill bit 1 and the secondary drill bit 2 by 5mm; S3, drilling tool assembly and drilling of large diameter boreholes (the diameter of the large diameter borehole is 130 mm): install the double clip assembly 7 in the third-level drill bit 3 and the end rotating tube 5, and use the drilling rig to connect the tail end of the end rotating tube 5 with the first connecting rotating tube 6, clamp the double clip assembly 7 with the connecting rotating tube 6, and then connect the water whip to the tail end of the first connecting rotating tube 6 to drill; Then remove the water whip, install the single clip assembly 8 at the tail end of the double clip assembly 7, and then use the drilling rig to connect the second connecting rotating tube 6 at the tail end of the first connecting rotating tube 6. After the connection is completed, the single clip assembly 8 is clamped with the second connecting rotating tube 6, and the water whip is installed to continue drilling; this cycle is repeated until the drilling depth reaches the designed depth of 20m, and the drilling of the 130mm large diameter borehole is completed; S4, drill bit change and drilling of small diameter hole (small diameter hole is 36mm): install the rotary joint 13 at the tail end of the last connecting rotary tube 6, then withdraw the drill as a whole by 400mm, and use a wrench to rotate the rotary joint 13 clockwise, so that all the second rotary tubes 603 in the connecting rotary tubes 6 and the first rotary tube 501 in the end rotary tube 5 rotate clockwise, at this time, the third-level drill bit tube body 301 will be at its first wing spring pin 302 and the lower part Under the joint action of the threads, the two first wing spring pins 302 of the tertiary drill bit tube body 301 are pushed forward along the inside of the secondary drill bit tube body 201 to the front end of the secondary drill bit track groove 202, and the two first wing spring pins 302 contact the control component 203 and trigger its action, so that the two secondary drill bit spring pins 204 outside the secondary drill bit tube body 201 are retracted, disengaged from the two pin holes 103 on the primary drill bit tube body 101, and placed in the primary drill bit track groove 102; Remove the rotary joint 13, reinstall the water whip, and make the front end of the three-stage drill bit 3 contact the bottom of the borehole for drilling. The drilling depth of the three-stage drill bit 3 is 35 cm. S5. Recovery of the tertiary drill bit 3: After the small-diameter hole is drilled, the water whip is removed and the rotary joint 13 is connected. The rotary joint 13 is rotated counterclockwise. At this time, the tertiary drill bit 3 will move backward along the secondary drill bit track groove 202 and rotate until the first rotary tube 501 is disengaged from the thread of the tertiary drill bit 3. At this time, the two first wing spring pins 302 of the tertiary drill bit 3 are located in the two notches 5013 at the front end of the first rotary tube 501; at this time, the last second double-wing spring pin 803 connected to the rotary tube 6 is continuously pulled backward, so that all the single snap-fit ​​components 8 and the double snap-fit ​​components 7 move backward together, so that the tertiary drill bit 3 passes through the first rotary tube 501 and all the second rotary tubes 603 in turn until the tertiary drill bit 3 is completely pulled out; S6. Install the stress gauge: inject adhesive into the inner cavity of the stress gauge, install the hollow inclusion strain gauge through all the second rotating tubes 603 and the first rotating tube 501 in sequence to the predetermined position in the small-diameter borehole after drilling, and then squeeze the adhesive from the inner cavity of the stress gauge into the gap between the stress gauge and the small-diameter borehole, and then wait for the adhesive inside the strain gauge to completely solidify, so as to firmly bond the stress gauge to the wall of the small-diameter borehole; S7, stress relief drilling: Since the two secondary drill bit spring pins 204 of the secondary drill bit 2 have retracted, after the water whip is installed and drilling is started, as the primary drill bit 1 continues to advance, the rock entering the interior will push the secondary drill bit 2 to move backward along the primary drill bit track groove 102 until the stress relief experiment is completed. During the whole process, the strain value monitored by the stress meter is recorded; S8, drill withdrawal: according to the normal drill withdrawal method, the connecting rotary tube 6, the primary drill bit 1, the secondary drill bit 2 and the tertiary drill bit 3 are removed in sequence.

[0032] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, many changes can be made in the specific implementation methods and application scopes based on the ideas of the present invention. As long as these changes do not deviate from the concept of the present invention, they all belong to the protection scope of the present invention.

Claims

1. A special multi-stage deformation drill for measuring ground stress by stress relief method, characterized in that: It includes a drill unit and a connection unit. The drill unit includes a primary drill bit, a secondary drill bit, a tertiary drill bit and a reducer. The connection unit includes an end rotating tube, a plurality of connecting rotating tubes, a buckle assembly and a rotating joint. The first-stage drill bit comprises a first-stage drill bit tube body which is hollow inside, a first-stage drill bit track groove and a pin hole are arranged in the first-stage drill bit tube body along the axial direction, and the tail end of the first-stage drill bit tube body is connected to the reducer; The secondary drill bit comprises a secondary drill bit tube body with a hollow interior, the secondary drill bit tube body is coaxially arranged in the primary drill bit tube body, a secondary drill bit spring pin is arranged on the secondary drill bit tube body, the secondary drill bit spring pin is matched with the pin hole to achieve connection, and can be slidably arranged in the primary drill bit track groove, a secondary drill bit track groove and a control component are axially arranged in the secondary drill bit tube body, and the control component is connected to the secondary drill bit spring pin; The three-stage drill bit comprises a three-stage drill bit tube body with a hollow interior, the three-stage drill bit tube body is coaxially arranged in the two-stage drill bit tube body, and a first wing spring pin is symmetrically arranged outside the three-stage drill bit tube body, and the first wing spring pin is slidably arranged in the two-stage drill bit track groove; The tertiary drill bit tube body is connected to the end rotating tube by a thread, and the end rotating tube is also connected to the reducer by a thread. The tail end of the end rotating tube is connected to several connecting rotating tubes in sequence. A snap assembly is provided in the tertiary drill bit tube body, the end rotating tube and all the connecting rotating tubes. The rotating joint is connected to the last connecting rotating tube and the snap assembly. Rotating the rotating joint drives the tertiary drill bit to move back and forth in the secondary drill bit.

2. The special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 1, characterized in that: The outer diameter of the first-stage drill bit tube body is 130 mm, the outer diameter of the second-stage drill bit tube body is 100 mm, and the outer diameter of the third-stage drill bit tube body is 36 mm; A plurality of first-level drill bit tooth platforms are distributed along the circumferential direction on the front end surface of the first-level drill bit tube body, and a first-level drill bit pick is provided on each first-level drill bit tooth platform, and the outer diameter of the first-level drill bit pick is at least 5 mm greater than the outer diameter of the first-level drill bit tube body; A plurality of secondary drill bit tooth platforms are distributed along the circumferential direction on the front end surface of the secondary drill bit tube body, and a secondary drill bit pick is arranged on each secondary drill bit tooth platform, and the outer diameter of the secondary drill bit pick is smaller than the outer diameter of the secondary drill bit tooth platform; A conical drill bit is provided at the front end of the three-stage drill bit tube body, and four top water outlet holes are provided on the conical drill bit, one of which is located at the top of the conical drill bit, and the other three are distributed at 120 degrees on the circumferential surface of the conical drill bit, and the three top water outlet holes are coplanar, and a plurality of outer water outlet holes are evenly opened on the three-stage drill bit tube body along the circumferential direction; The number of the first-level drill track grooves is 2, which are symmetrically arranged in the first-level drill tube body, and the number of the pin holes is 2, which are respectively located at the front end of each drill track groove; The number of the secondary drill bit spring pins is 2, the number of the secondary drill bit tracks is 2, and the number of the first wing spring pins is 2; Each of the first wing spring pins is connected to a first compression spring chamber, and the first compression spring chamber is located in the third-stage drill bit tube body.

3. The special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 1, characterized in that: The end rotating tube comprises a first rotating tube, a first bearing and a tail tube, the tail end of the first rotating tube is rotatably connected to the tail tube through the first bearing, the tail end of the third-stage drill bit body is threadedly connected to the front end of the first rotating tube and placed together in the second-stage drill bit, the front end of the tail tube is connected to the reducer, and the tail end of the tail tube is sequentially connected to a plurality of connecting rotating tubes; The connecting rotating tube comprises an outer tube body, a second bearing and a second rotating tube; the second rotating tube is located inside the outer tube body, and the two are coaxial, and both ends of the second rotating tube are respectively connected to the outer tube body for rotation via the second bearing; the outer tube bodies and second rotating tubes of adjacent connecting rotating tubes are respectively connected via threads, the first second rotating tube is connected to the first rotating tube via threads, and the first outer tube body is connected to the tail tube via threads; By rotating the rotating joint clockwise or counterclockwise, all the second rotating tubes and the first rotating tube are driven to rotate clockwise or counterclockwise, thereby driving the tertiary drill bit to move forward or backward in the secondary drill bit.

4. The special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 3, characterized in that: The front end of the tail pipe is provided with a tail pipe internal thread for connecting with the reducer, and the tail end of the tail pipe is provided with a tail pipe external thread for connecting with the second rotating pipe connected to the first rotating pipe; The tail end of the three-stage drill bit tube body is provided with a three-stage drill bit external thread, the front end of the first rotating tube is provided with a first internal thread for connecting with the three-stage drill bit external thread, and the front end of the first rotating tube is symmetrically provided with two notches, and the tail end of the first rotating tube is provided with a first external thread; two first clamping holes are symmetrically provided at the first external thread; The front end of the external tube body of each connecting rotating tube is provided with an external tube body internal thread, the external tube body internal thread of the first connecting rotating tube is used to connect with the external tube body thread of the tail tube, and the tail end of the external tube body is provided with an external tube body external thread, which is used to connect with the external tube body internal thread of the adjacent connecting rotating tube; each second rotating tube is provided with a second internal thread at the front end and a second external thread at the tail end; Two first clamping grooves are symmetrically arranged at the second internal thread of the second rotating tube, and the depth of the two first clamping grooves is 1 / 2 of the thickness of the second rotating tube; two second clamping holes are symmetrically arranged at the second external thread of the second rotating tube; The two first slots on the first second rotating tube connected to the rotating tube correspond to the two first holes on the first rotating tube in position and size, and the two first slots on the other two adjacent second rotating tubes correspond to the two second holes in position and size.

5. The special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 1, characterized in that: The buckle assembly includes a double buckle assembly and a single buckle assembly. The double buckle assembly is arranged in the first rotating tube, and the single buckle assembly is arranged in each second rotating tube. Adjacent single buckle assemblies are buckled and connected, and each single buckle assembly is buckled with the second rotating tube outside it and the connection of the next second rotating tube to connect the adjacent second rotating tubes; the first single buckle assembly is buckled and connected with the double buckle assembly, one end of the double buckle assembly is buckled and connected with the third-level drill bit tube body, and the other end is buckled with the first rotating tube and the connection of the first second rotating tube, so that the third-level drill bit tube body, the end rotating tube and the first connecting rotating tube are connected together; The double buckle assembly includes two first buckles, a first steel wire rope and a first double-wing spring pin, the two first buckles are connected to two pull rings in the tail end of the third-level drill bit tube body, the bottoms of the two first buckles are respectively connected to the first double-wing spring pin through the first steel wire rope, the first double-wing spring pin and the first steel wire rope pass through the inside of the first rotating tube, and the first double-wing spring pin is connected to the two first clamping holes on the first rotating tube; The single buckle assembly includes a second buckle, a second steel wire rope and a second double-wing spring pin, and the bottom of the second buckle is connected to the second double-wing spring pin through the second steel wire rope; the second buckle is used to connect with the first double-wing spring pin in the adjacent double buckle assembly or the second double-wing spring pin in the single buckle assembly; The first double-wing spring pin and the second double-wing spring pin have the same structure, both comprising a second compression spring chamber, two second wing spring pins, an upper hanging ring and a lower hanging ring. A second wing spring pin is respectively provided on the left and right sides of the second compression spring chamber, and an upper hanging ring and a lower hanging ring are respectively provided at the upper and lower ends of the second compression spring chamber. The upper hanging ring is used to connect the first steel wire rope or the second steel wire rope, and the lower hanging ring is used to connect with the first buckle or the second buckle.

6. The special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 1, characterized in that: The control assembly includes a driving shaft, a connecting shaft, a fixed platform, a slide rail, a limit spring pin, a connecting rod, a spring platform and a spring. A cavity connected to the secondary drill bit track groove is provided in front of the secondary drill bit track groove, and the cavity is also connected to the pin hole. The driving shaft is placed in the secondary drill bit track groove, and two parallel connecting plates are provided at the front end of the driving shaft. A fixed platform is provided between the two connecting plates. The connecting plates and the fixed platform are both placed in the cavity. An inclined slide rail is provided on the fixed platform. Connecting shafts are installed on the two connecting plates. The connecting shaft is slidably placed in the slide rail. A limit spring pin is also provided in the slide rail. A There is a connecting rod, on which a spring platform is provided, which is fixed on the inner wall of the cavity, and the end of the connecting rod is fixed to the secondary drill spring pin, and a spring is provided on the outside of the connecting rod between the spring platform and the secondary drill spring pin; when the active shaft is subjected to force, the active shaft drives the connecting plate to move forward, thereby driving the connecting shaft to move upward along the slide rail. At this time, the fixed platform moves together with the connecting rod to the side away from the secondary drill spring pin, thereby driving the secondary drill spring pin to compress the spring and retract to one side of the cavity along the pin hole, and when the connecting shaft moves above the limit spring pin, the limit spring pin pops out to limit it.

7. The special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 1, characterized in that: The rotary joint comprises a square end and a joint tube body, the square end is a solid structure, a hollow joint tube body is arranged at the front end of the square end, a third internal thread is arranged at the front end of the joint tube body, and the second external thread of the last second rotary tube is matched, and two symmetrically arranged second clamping grooves are arranged at the third internal thread, and the two second clamping grooves correspond to the positions and sizes of the two second clamping holes of the second rotary tube; The rotating joint is rotated clockwise to drive all the second rotating tubes and the first rotating tube to rotate clockwise, and the two first wing spring pins outside the third-level drill bit tube body are controlled to move forward along the second-level drill bit track groove through the thread of the tail end of the third-level drill bit tube body and the first rotating tube, thereby driving the control component to operate, control the two spring pins of the second-level drill bit tube body to retract, disengage from the pin holes of the first-level drill bit tube body, and place them in the first-level drill bit track groove; Rotate the rotary joint counterclockwise to drive all the connecting rotary tubes and the end rotary tube to rotate counterclockwise, so that the end rotary tube is separated from the tertiary drill bit tube body. After disassembling the rotary joint, pull the single clip assembly in the last connecting rotary tube backward, and pull all the single clip assemblies, double clip assemblies and the tertiary drill bit out through the end rotary tube and the connecting rotary tube.

8. A method for using a special multi-stage deformable drilling tool for measuring ground stress using a stress relief method, which is implemented by using the special multi-stage deformable drilling tool for measuring ground stress using a stress relief method as claimed in any one of claims 1 to 7, characterized in that: The specific steps include: S1. Use a drilling rig and a φ130mm drill bit to drill a hole 1m deep at the measurement location; S2. Drill bit assembly: remove the φ130mm drill bit and drill rod, assemble the first-level drill bit, second-level drill bit, third-level drill bit and end rotating tube together and put them into the drill hole, and adjust the position of the third-level drill bit by rotating the end rotating tube so that its front end protrudes from the front ends of the first-level drill bit and the second-level drill bit; S3, Drilling tool assembly and drilling of large diameter boreholes: Install a double clip assembly in the third-stage drill bit and the end rotating tube, and use a drilling rig to connect the tail end of the end rotating tube to the first connecting rotating tube, clamp the double clip assembly to the connecting rotating tube, and then connect the water whip to the tail end of the first connecting rotating tube to drill; Then remove the water whip, install a single clip assembly at the tail end of the double clip assembly, and then use the drilling rig to connect the second connecting rotating tube at the tail end of the first connecting rotating tube. After the connection is completed, the single clip assembly is connected to the second connecting rotating tube, and the water whip is installed to continue drilling; this cycle is repeated until the drilling depth reaches the designed depth, and the drilling of the large-diameter borehole is completed; S4. Drill bit change and drilling of small diameter holes: install the rotary joint at the tail end of the last connecting rotary tube, then withdraw the drill as a whole by 400mm, and use a wrench to rotate the rotary joint clockwise, so that the second rotary tubes in all the connecting rotary tubes and the first rotary tube in the end rotary tube rotate clockwise. At this time, the third-level drill bit tube body will push the first wing spring pin of the third-level drill bit tube body to move forward along the inside of the second-level drill bit tube body to the front end of the second-level drill bit track groove under the joint action of its first wing spring pin and thread. The two first wing spring pins contact with the control component and trigger its action, so that the two second-level drill bit spring pins outside the second-level drill bit tube body are retracted, disengaged from the two pin holes on the first-level drill bit tube body, and placed in the first-level drill bit track groove; Remove the rotary joint, reinstall the water whip, and make the front end of the three-stage drill bit contact the bottom of the hole for drilling. The drilling depth of the three-stage drill bit is 35cm; S5. Recovery of the third-stage drill bit: After the small-diameter hole is drilled, the water whip is removed and the rotary joint is connected. The rotary joint is rotated counterclockwise. At this time, the third-stage drill bit will move backward along the second-stage drill bit track groove. If the hole is drilled upward, the second-stage drill bit will also move downward under the action of its own weight; it keeps rotating until the first rotary tube is disengaged from the thread of the third-stage drill bit. At this time, the first wing spring pin wing of the third-stage drill bit is located in the two notches at the front end of the first rotary tube; at this time, the last second double-wing spring pin connected to the rotary tube is continuously pulled backward, so that all the single-buckle components and the double-buckle components move backward together, so that the third-stage drill bit passes through the first rotary tube and all the second rotary tubes in turn until the third-stage drill bit is completely pulled out; S6. Install the stress gauge: inject adhesive into the inner cavity of the stress gauge, install the hollow inclusion strain gauge through all the second rotating tubes and the first rotating tube in turn to the predetermined position in the small-diameter borehole after drilling, and then squeeze the adhesive from the inner cavity of the stress gauge into the gap between the stress gauge and the small-diameter borehole, and then wait for the adhesive inside the strain gauge to completely solidify, and firmly bond the stress gauge to the wall of the small-diameter borehole; S7, stress relief drilling: Since the two spring pins of the secondary drill bit have retracted, after installing the water whip and drilling, as the primary drill bit continues to advance, the rock entering the interior will push the secondary drill bit to move backward along the primary drill bit track groove until the stress relief experiment is completed. During the whole process, the strain value monitored by the stress meter is recorded; S8. Drill withdrawal: According to the normal drill withdrawal method, the connecting rotary tube, the first-stage drill bit, the second-stage drill bit and the third-stage drill bit are removed in sequence.

9. The method for using the special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 8, characterized in that: In step S2, the assembly of the first-stage drill bit, the second-stage drill bit and the third-stage drill bit is specifically as follows: firstly, the reducer is installed on the tail tube of the end rotating tube, and then the tail end of the third-stage drill bit body is connected to the first rotating tube of the end rotating tube through threads; Before connection, first connect the two pull rings below the tertiary drill bit tube body to the two first buckles in the double buckle assembly, and connect a first steel wire rope to each of the two first buckles. The two first steel wire ropes are respectively connected to the upper hanging rings of the first double-wing spring pin, and the first double-wing spring pin and the first steel wire rope are respectively passed through the end rotating tube. Then, the secondary drill bit tube body is sleeved on the outside of the tertiary drill bit tube body, and the two first wing spring pins on the tertiary drill bit tube body are respectively placed at the bottom of the secondary drill bit rail groove on the inner side of the secondary drill bit tube body. Then, the primary drill bit is sleeved on the outside of the secondary drill bit, so that the spring pin outside the secondary drill bit tube body is located in the pin hole of the primary drill bit tube body. After completion, the position of the tertiary drill bit is adjusted by rotating the first rotating tube of the end rotating tube clockwise so that the top of the conical drill bit of the tertiary drill bit exceeds the front end of the primary drill bit and the secondary drill bit by 5 mm.

10. The method for using the special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 8, characterized in that: The diameter of the large-diameter drill hole is 130 mm, and the diameter of the small-diameter drill hole is 36 mm.

Images