Special multi-stage deformation drill tool for in-situ stress measurement by stress relief method and its usage method

Abstract

The present invention belongs to the technical field of drilling engineering, and discloses a special multi-stage deformation drill tool for stress relief method in-situ stress measurement and its usage method. The special multi-stage deformation drill tool for stress relief method in-situ stress measurement includes a drill bit unit and a connection unit. The drill bit unit includes a first-stage drill bit, a second-stage drill bit, a third-stage drill bit and a reducing pipe; the connection unit includes a head rotating pipe, several connecting rotating pipes, a snap component and a rotary joint. The multi-stage deformation drill tool of the present invention can complete the formation of all large-diameter holes and small-diameter holes in one drilling through the connection and transformation between the first-stage drill bit, the second-stage drill bit, the third-stage drill bit, the end connection pipe and the connecting rotating pipe with different diameters, and stress relief construction can be carried out without replacing the drill bit, and the overall operation steps are simple. The present invention has strong adaptability to existing drilling rig equipment and strain gauges, and can be perfectly combined with existing drilling and detection devices.

Description

Technical Field

[0001] The present invention belongs to the technical field of drilling engineering, and particularly relates to a special multi-stage deformation drill tool for in-situ stress measurement by the stress relief method and a using method thereof. Background Art

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

[0003] At present, the main methods for measuring in-situ stress include the stress recovery method, the stress relief method, the strain relief method, the hydraulic fracturing method, the acoustic emission method, the X-ray method, the gravity method, etc. Among them, the stress relief method is a relatively mature in-situ stress measurement method that is most commonly used. 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 position, and then cut a groove or ream a hole around the installed measuring element to separate the rock with the measuring element installed from the surrounding rock mass, that is, to release this part of the rock from the action of the measured stress field; at this time, the measured point rock will produce elastic recovery deformation due to the disappearance of the external force; by measuring this deformation, the magnitude and direction of the in-situ stress can be calculated. When using this method for in-situ stress measurement, first, a borehole with a depth of about 20 m and a diameter of 130 mm needs to be drilled in the rock stratum; then, the drill is withdrawn and the drill bit is replaced with a small drill bit with a diameter of 36 mm, and a small borehole with a depth of 350 mm is continuously drilled at the bottom of the original borehole; then, the drill is withdrawn again and replaced with a core drill bit with a diameter of 130 mm, the stress gauge (hollow inclusion strain gauge) is installed in the small borehole, and the external connection wire of the stress gauge is passed through each drill pipe in turn; finally, a stress relief experiment is carried out, and the change of the stress gauge is monitored in real time during the process of taking the core, and then the corresponding in-situ stress is calculated. It can be seen from this that this method requires multiple drill withdrawals and drill bit replacements in the specific implementation process, with cumbersome steps and time-consuming and laborious; at the same time, the external connection wire of the stress gauge needs to pass through each drill pipe in turn, and its operation is also very complicated, making the connection between drill pipes very time-consuming. Therefore, a drill tool that can eliminate the need for repeated drill withdrawals, drill bit replacements, and rapid installation of stress gauges is needed to improve the convenience of using the stress relief method. Summary of the Invention

[0004] To solve the above problems, the present invention provides a special multi-stage deformation drill for in-situ stress measurement by the stress relief method and a usage method thereof.

[0005] To achieve the above object, the present invention adopts the following technical solutions: A special multi-stage deformation drill for in-situ stress measurement by the stress relief method, comprising a drill bit unit and a connection unit. The drill bit unit includes a first-stage drill bit, a second-stage drill bit, a third-stage drill bit and a reducing pipe; the connection unit includes a head rotating pipe, a plurality of connecting rotating pipes, a snap component and a rotary joint.

[0006] The first-stage drill bit includes a first-stage drill bit body with a hollow interior. Along the axial direction, a first-stage drill bit rail groove and a pin hole are provided in the first-stage drill bit body. The tail end of the first-stage drill bit body is connected to the reducing pipe.

[0007] The second-stage drill bit includes a second-stage drill bit body with a hollow interior. The second-stage drill bit body is coaxially placed in the first-stage drill bit body. A second-stage drill bit spring pin is provided on the second-stage drill bit body. The second-stage drill bit spring pin is engaged with the pin hole to achieve connection and is slidably placed in the first-stage drill bit rail groove. Along the axial direction, a second-stage drill bit rail groove and a control component are provided in the second-stage drill bit body. The control component is connected to the second-stage drill bit spring pin.

[0008] The third-stage drill bit includes a third-stage drill bit body with a hollow interior. The third-stage drill bit body is coaxially placed in the second-stage drill bit body. Symmetrically arranged on the outside of the third-stage drill bit body are first wing spring pins, which are slidably placed in the second-stage drill bit rail groove.

[0009] The third-stage drill bit body is threadedly connected to the head rotating pipe. The head rotating pipe is also threadedly connected to the reducing pipe. The tail end of the head rotating pipe is sequentially connected to a plurality of connecting rotating pipes. A snap component is provided in the third-stage drill bit body, the head rotating pipe and all the connecting rotating pipes. The rotary joint is connected to the last connecting rotating pipe and the snap component. Rotating the rotary joint drives the third-stage drill bit to move back and forth in the second-stage drill bit.

[0010] Further, the outer diameter of the first-stage drill bit body is 130 mm, the outer diameter of the second-stage drill bit body is 100 mm, and the outer diameter of the third-stage drill bit body is 36 mm.

[0011] On the front end face of the first-stage drill bit body, a plurality of first-stage drill bit tooth platforms are circumferentially distributed. On each first-stage drill bit tooth platform, a first-stage drill bit pick is provided. The outer diameter of the first-stage drill bit pick is at least 5 mm larger than the outer diameter of the first-stage drill bit body.

[0012] On the front end face of the second-stage drill bit body, a plurality of second-stage drill bit tooth platforms are circumferentially distributed. On each second-stage drill bit tooth platform, a second-stage drill bit pick is provided. The outer diameter of the second-stage drill bit pick is smaller than the outer diameter of the second-stage drill bit tooth platform.

[0013] The front end of the three-stage drill bit body is provided with a conical drill bit, and 4 top water outlet holes are provided on the conical drill bit. One of the top water outlet holes is located at the top of the conical drill bit, and the other three are distributed at 120° on the circumferential surface of the conical drill bit, and these three top water outlet holes are coplanar. A plurality of outer water outlet holes are also evenly opened on the three-stage drill bit body along the circumferential direction;

[0014] The number of the first-stage drill bit rail grooves is 2, which are symmetrically arranged in the first-stage drill bit body. The number of the pin holes is 2, which are respectively located at the front ends of each first-stage drill bit rail groove;

[0015] The number of the second-stage drill bit spring pins is 2, the number of the second-stage drill bit tracks is 2, and the number of the first wing spring pins is 2;

[0016] 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 three-stage drill bit body.

[0017] Further, the end rotating pipe includes a first rotating pipe, a first bearing and a tail pipe. The tail end of the first rotating pipe is rotationally connected to the tail pipe through the first bearing. The tail end of the three-stage drill bit body is threadedly connected to the front end of the first rotating pipe and they are both placed in the second-stage drill bit. The front end of the tail pipe is connected to the reduced-diameter pipe, and several connecting rotating pipes are sequentially connected to the tail end of the tail pipe;

[0018] The connecting rotating pipe includes an outer pipe body, a second bearing and a second rotating pipe; the second rotating pipe is located inside the outer pipe body and they are coaxial. The two ends of the second rotating pipe are respectively rotationally connected to the outer pipe body through the second bearing; the outer pipe bodies and the second rotating pipes of adjacent connecting rotating pipes are respectively threadedly connected, the first second rotating pipe is threadedly connected to the first rotating pipe, and the first outer pipe body is threadedly connected to the tail pipe;

[0019] By rotating the rotary joint clockwise or counterclockwise to drive all the second rotating pipes and the first rotating pipe to rotate clockwise or counterclockwise, the three-stage drill bit is driven to move forward or backward in the second-stage drill bit.

[0020] Further, the front end of the tail pipe is provided with an internal thread of the tail pipe for connecting to the reduced-diameter pipe, and the tail end of the tail pipe is provided with an external thread of the tail pipe for connecting to the second rotating pipe of the first connecting rotating pipe;

[0021] The tail end of the three-stage drill bit body is provided with an external thread of the three-stage drill bit. The front end of the first rotating pipe is provided with an internal thread for connecting to the external thread of the three-stage drill bit. And 2 notches are symmetrically arranged at the front end of the first rotating pipe. The tail end of the first rotating pipe is provided with an external thread; 2 first clamping holes are symmetrically arranged at the external thread.

[0022] The front end of the outer tube body of each of the connecting rotary tubes is provided with an internal thread of the outer tube body. The internal thread of the outer tube body of the first connecting rotary tube is used to connect with the external thread of the tail tube. The tail end of the outer tube body is provided with an external thread of the outer tube body, which is used to connect with the internal thread of the outer tube body of the adjacent connecting rotary tube; the front end of each second rotary tube is provided with a second internal thread, and the tail end is provided with a second external thread;

[0023] Two first clamping grooves are symmetrically arranged at the second internal thread of the second rotary tube. The depth of the two first clamping grooves is 1 / 2 of the thickness of the second rotary tube; two second clamping holes are symmetrically arranged at the second external thread of the second rotary tube;

[0024] The positions and sizes of the two first clamping grooves on the second rotary tube of the first connecting rotary tube correspond to the positions and sizes of the two first clamping holes on the first rotary tube. The positions and sizes of the two first clamping grooves and the two second clamping holes on the other adjacent two second rotary tubes correspond to each other.

[0025] Furthermore, the buckle assembly includes a double buckle assembly and a single buckle assembly. A double buckle assembly is arranged inside the first rotary tube, and a single buckle assembly is arranged inside each second rotary tube. The adjacent single buckle assemblies are buckled and connected. Each single buckle assembly is clamped at the connection between its external second rotary tube and the next second rotary tube to connect the adjacent second rotary 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 body of the three-stage drill bit, and the other end is clamped at the connection between the first rotary tube and the first second rotary tube to connect the body of the three-stage drill bit, the end rotary tube and the first connecting rotary tube together;

[0026] 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 with two pull rings inside the tail end of the body of the three-stage drill bit. The bottoms of the two first buckles are respectively connected with 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 rotary tube, and the first double-wing spring pin is connected with the two first clamping holes on the first rotary tube;

[0027] The single buckle assembly includes one second buckle, a second steel wire rope and a second double-wing spring pin. The bottom of the second buckle is connected with 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;

[0028] The first double-wing spring pin and the second double-wing spring pin have the same structure, both including a second spring compression chamber, two second wing spring pins, an upper hanging ring and a lower hanging ring. One second wing spring pin is provided on each of the left and right sides of the second spring compression chamber, and the upper hanging ring and the lower hanging ring are respectively provided at the upper and lower ends of the second spring compression chamber. The upper hanging ring is used for connecting to the first steel wire rope or the second steel wire rope, and the lower hanging ring is used for connecting to the first buckle or the second buckle.

[0029] Further, 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 communicating with it is provided in front of the secondary drill bit track groove, and the cavity also communicates with a 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, and 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 and slides in the slide rail. A limit spring pin is also provided in the slide rail. A connecting rod is provided outside the fixed platform, and a spring platform is provided on the connecting rod. The spring platform is fixed on the inner wall of the cavity. The end of the connecting rod is fixed to the secondary drill bit spring pin, and a spring is provided outside the connecting rod between the spring platform and the secondary drill bit spring pin; when the driving shaft is stressed, the driving shaft drives the connecting plate to move forward, thereby driving the connecting shaft to move obliquely upward along the slide rail. At this time, the fixed platform together with the connecting rod moves away from the secondary drill bit spring pin side, thereby driving the secondary drill bit spring pin to compress the spring and retract along the pin hole to the cavity side. When the connecting shaft moves above the limit spring pin, the limit spring pin pops out to limit it.

[0030] Further, the rotary joint includes a square end and a joint pipe body. The square end is a solid structure, and a hollow joint pipe body is provided at the front end of the square end. The front end of the joint pipe body is provided with a third internal thread, which matches the second external thread of the last second rotary pipe, and two symmetrically arranged second card slots are provided at the third internal thread. The positions and sizes of the two second card slots correspond to the two second card holes of the second rotary pipe;

[0031] Rotate the rotary joint clockwise to drive all the second rotary pipes and the first rotary pipe to rotate clockwise, and through the thread between the tail end of the tertiary drill bit pipe body and the first rotary pipe, control the two first wing spring pins outside the tertiary drill bit pipe body to move forward along the secondary drill bit track groove, and further drive the control assembly to act, control the two spring pins of the secondary drill bit pipe body to retract, disengage from the pin holes of the primary drill bit pipe body, and be placed in the primary drill bit track groove;

[0032] Rotate the rotary joint counterclockwise to drive all the connecting rotary pipes and the end rotary pipe to rotate counterclockwise, so that the end rotary pipe is disengaged from the three-stage drill pipe body. After removing the rotary joint, pull the single snap component inside the last connecting rotary pipe backward to completely pull out all the single snap components, double snap components and the three-stage drill bit through the end rotary pipe and the connecting rotary pipe.

[0033] The present invention also provides a method for using a special multi-stage deformation drill for in-situ stress measurement by the stress relief method, which is realized by using the above-mentioned special multi-stage deformation drill for in-situ stress measurement by the stress relief method, and specifically includes the following steps:

[0034] S1. Use a drill rig and a φ130mm drill bit to drill a hole with a depth of 1m at the measurement site;

[0035] S2. Bit assembly: Withdraw the φ130mm drill bit and drill pipe, assemble the first-stage drill bit, second-stage drill bit, third-stage drill bit and the end rotary pipe together and put them into the hole, and adjust the position of the third-stage drill bit by rotating the end rotary pipe so that its front end protrudes from the front ends of the first-stage drill bit and the second-stage drill bit;

[0036] S3. Drill tool assembly and drilling of large-diameter holes: Install a double snap component in the third-stage drill bit and the end rotary pipe, use a drill rig to connect the tail end of the end rotary pipe to the first connecting rotary pipe, snap the double snap component to the connecting rotary pipe, and then connect the water whip to the tail end of the first connecting rotary pipe for drilling;

[0037] Then remove the water whip, install a single snap component at the tail end of the double snap component, then use a drill rig to connect the second connecting rotary pipe at the tail end of the first connecting rotary pipe. After the connection is completed, snap the single snap component to the second connecting rotary pipe and install the water whip to continue drilling; Repeat this process until the drilling depth reaches the designed depth to complete the drilling of the large-diameter hole;

[0038] S4. Bit transformation and drilling of small-diameter holes: Install the rotary joint at the tail end of the last connecting rotary pipe, then retract the drill bit as a whole by 400mm, and use a wrench to rotate the rotary joint clockwise so that the second rotary pipe in all the connecting rotary pipes and the first rotary pipe in the end rotary pipe rotate clockwise. At this time, the three-stage drill pipe body will, under the combined action of its first wing spring pin and thread, push the first wing spring pin of the three-stage drill pipe body forward along the inside of the second-stage drill pipe body to the front end of the second-stage drill rail groove. The two first wing spring pins contact the control component and trigger its action, causing the two second-stage drill spring pins outside the second-stage drill pipe body to retract, disengage from the two pin holes on the first-stage drill pipe body, and be placed in the first-stage drill rail groove;

[0039] Remove the rotary joint, reinstall the water whip, and make the front end of the three-stage drill bit contact the bottom of the borehole for drilling. The drilling depth of the three-stage drill bit is 35 cm;

[0040] S5. Recovery of the three-stage drill bit: After the drilling of the small-diameter borehole is completed, remove the water whip and connect the rotary joint. Rotate the rotary joint counterclockwise. At this time, the three-stage drill bit will move backward along the groove of the second-stage drill bit. If the borehole is an upward borehole, the second-stage drill bit will also move downward under its own weight; keep rotating until the thread between the first rotating pipe and the three-stage drill bit is disengaged. At this time, the first wing spring pin of the three-stage drill bit is located in the two notches at the front end of the first rotating pipe; at this time, continuously pull the second double-wing spring pin in the last connecting rotating pipe backward, so that all the single snap components and double snap components move backward together, and the three-stage drill bit passes through the first rotating pipe and all the second rotating pipes in turn until the three-stage drill bit is completely pulled out;

[0041] S6. Install the stress gauge: Inject the binder into the inner cavity of the stress gauge, install the hollow inclusion strain gauge into the predetermined position in the small-diameter borehole after drilling through all the second rotating pipes and the inside of the first rotating pipe in turn, then squeeze the binder out of the inner cavity of the stress gauge into the gap between the stress gauge and the small-diameter borehole, and then wait for the binder inside the strain gauge to completely solidify, and bond the stress gauge firmly to the wall of the small-diameter borehole;

[0042] S7. Stress relief drilling: Since the two spring pins of the second-stage drill bit have retracted, when the water whip is installed and drilled at this time, as the first-stage drill bit continues to advance, the rock entering the interior will push the second-stage drill bit to move backward along the groove of the first-stage drill bit until the stress relief experiment is completed. Record the strain values monitored by the stress gauge throughout the process;

[0043] S8. Drill withdrawal: Remove the connecting rotating pipes, the first-stage drill bit, the second-stage drill bit, and the third-stage drill bit in turn according to the normal drill withdrawal method.

[0044] Further, in the 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: First, install the reducer on the tail pipe of the end rotating pipe, and then connect the tail end of the three-stage drill bit pipe body to the first rotating pipe of the end rotating pipe through threads;

[0045] Before connection, first connect the 2 pull rings below the three-stage drill pipe body to the 2 first buckles in the double-buckle assembly, and connect a first steel wire rope to each of the 2 first buckles. The two first steel wire ropes are respectively connected to the upper hanging rings of the first double-wing spring pins. Pass the first double-wing spring pins and the first steel wire ropes through the end rotating pipe respectively, and then sleeve the two-stage drill pipe body outside the three-stage drill pipe body, and make the 2 first wing spring pins on the three-stage drill pipe body respectively located at the bottom of the two-stage drill track grooves inside the two-stage drill pipe body. Then sleeve the first-stage drill bit outside the second-stage drill bit, so that the spring pins outside the two-stage drill pipe body are located in the pin holes of the first-stage drill pipe body. After completion, adjust the position of the three-stage drill bit by clockwise rotating the first rotating pipe of the end rotating pipe, so that the conical drill bit tip of the three-stage drill bit extends 5 mm beyond the front ends of the first-stage drill bit and the second-stage drill bit.

[0046] Furthermore, the diameter of the large-diameter drilling is 130 mm, and the diameter of the small-diameter drilling is 36 mm.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) Through the connection and transformation between the first-stage drill bit, the second-stage drill bit, the third-stage drill bit, the end connection pipe, and the connection rotating pipe with different diameters, the multi-stage deformable drill tool of the present invention can complete the formation of all large-diameter drillings and small-diameter drillings in one drilling, and can perform stress relief construction without replacing the drill bit, and the overall operation steps are simple;

[0049] (2) When measuring the in-situ stress by the stress relief method of the present invention, the installation of the strain gauge is convenient. It is not necessary to pass its external wiring through each drill pipe in turn. It only needs to be directly installed in place through the connection rotating pipe and the internal part of the end rotating pipe through the installation rod, and the construction is simple and convenient;

[0050] (3) Due to the structural design of the end connection pipe and the connection rotating pipe of the multi-stage deformable drill tool of the present invention, the drill tool has strong adaptability to the existing drilling rig equipment and strain gauges, and can be perfectly combined with the existing drilling and detection devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic external structure diagram of the special multi-stage deformable drill tool for in-situ stress measurement by the stress relief method of the present invention;

[0052] Figure 2 It is a schematic front-end structure diagram of the drill bit unit of the present invention;

[0053] Figure 3 It is a schematic rear-end structure diagram of the drill bit unit of the present invention;

[0054] Figure 4 It is one of the schematic structure diagrams of the first-stage drill bit and the diameter-changing connection of the present invention;

[0055] Figure 5 It is the second structural schematic diagram of the connection between the first-stage drill bit and the diameter-changing connection of the present invention;

[0056] Figure 6 It is the first structural schematic diagram of the second-stage drill bit of the present invention;

[0057] Figure 7 It is the second structural schematic diagram of the second-stage drill bit of the present invention;

[0058] Figure 8 It is the first structural schematic diagram of the connection between the control component and the spring pin of the second-stage drill bit of the present invention;

[0059] Figure 9 It is the structural schematic diagram of the connection between the control component and the spring pin of the second-stage drill bit inside the second-stage drill bit, and the spring pin of the second-stage drill bit is in the ejected state;

[0060] Figure 10 It is the structural schematic diagram of the connection between the control component and the spring pin of the second-stage drill bit inside the second-stage drill bit, and the spring pin of the second-stage drill bit is in the retracted state;

[0061] Figure 11 It is the front-end structural schematic diagram of the third-stage drill bit of the present invention;

[0062] Figure 12 It is the rear-end structural schematic diagram of the third-stage drill bit of the present invention;

[0063] Figure 13 It is the front-end structural schematic diagram of the end rotating pipe of the present invention;

[0064] Figure 14 It is the rear-end structural schematic diagram of the end rotating pipe of the present invention;

[0065] Figure 15 It is the structural schematic diagram of the connecting rotating pipe of the present invention;

[0066] Figure 16 It is the structural schematic diagram of the second connecting pipe of the present invention;

[0067] Figure 17 It is the structural schematic diagram of the connection between the double snap component and the single snap component of the present invention;

[0068] Figure 18 It is the structural schematic diagram of the double-wing spring pin of the present invention;

[0069] Figure 19 It is the structural schematic diagram of the rotary joint of the present invention.

[0070] Markings in the figure: 1. First-stage drill bit; 101. First-stage drill bit body; 102. First-stage drill bit track groove; 103. Pin hole; 104. First-stage drill bit tooth table; 105. First-stage drill bit pick

[0071] 2. Secondary drill bit; 201. Secondary drill bit body; 202. Secondary drill bit rail groove; 203. Control assembly; 2031. Driving 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;

[0072] 204. Secondary drill bit spring pin; 205. Secondary drill bit tooth platform; 206. Secondary drill bit cutting pick;

[0073] 3. Tertiary drill bit; 301. Tertiary drill bit body; 302. First wing spring pin; 303. First compression spring chamber; 304. Tapered drill bit; 305. Top water outlet hole; 306. Outer water outlet hole; 307. Pull ring; 308. External thread of tertiary drill bit;

[0074] 4. Reducing pipe;

[0075] 5. End rotating pipe; 501. First rotating pipe; 5011. First internal thread; 5012. First external thread; 5013. Notch; 5014. First clamping hole; 502. First bearing; 503. Tail pipe; 5031. Internal thread of tail pipe; 5032. External thread of tail pipe;

[0076] 6. Connecting rotating pipe; 601. External pipe body; 6011. Internal thread of external pipe body; 6012. External thread of external pipe body; 602. Second bearing; 603. Second rotating pipe; 6031. Second internal thread; 6032. Second external thread; 6033. First clamping groove; 6034. Second clamping hole;

[0077] 7. Double buckle assembly; 701. First buckle; 702. First steel wire rope; 703. First double wing spring pin;

[0078] 8. Single buckle assembly; 801. Second buckle; 802. Second steel wire rope; 803. Second double wing spring pin;

[0079] 9. Second compression spring chamber; 10. Second wing spring pin; 11. Upper hanging ring; 12. Lower hanging ring;

[0080] 13. Rotary joint; 1301. Square end; 1302. Joint pipe body; 1303. Third internal thread; 1304. Second clamping groove. Detailed implementation manners

[0081] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below.

[0082] Embodiment 1

[0083] Refer to Figures 1-19 , a special multi-stage deformation drill for in-situ stress measurement by the stress relief method, comprising a drill bit unit and a connection unit. The drill bit unit includes a first-stage drill bit 1, a second-stage drill bit 2, a third-stage drill bit 3 and a reducing pipe 4; the connection unit includes a head rotating pipe 5, several connecting rotating pipes 6, a snap component and a rotary joint 13;

[0084] Refer to Figure 4 and Figure 5 , the first-stage drill bit 1 includes a first-stage drill bit body 101 with a hollow interior. Along the axial direction inside the first-stage drill bit body 101, there is a first-stage drill bit track groove 102 and a pin hole 103. The tail end of the first-stage drill bit body 101 is connected to the reducing pipe 4;

[0085] Refer to Figure 6 and Figure 7 , the second-stage drill bit 2 includes a second-stage drill bit body 201 with a hollow interior. The second-stage drill bit body 201 is coaxially placed in the first-stage drill bit body 101. On the second-stage drill bit body 201, there is a second-stage drill bit spring pin 204. The second-stage drill bit spring pin 204 is engaged with the pin hole 103 to achieve connection and is slidably placed in the first-stage drill bit track groove 102. Along the axial direction inside the second-stage drill bit body 201, there is a second-stage drill bit track groove 202 and a control component 203. The control component 203 is connected to the second-stage drill bit spring pin 204;

[0086] Refer to Figures 11-12 , the third-stage drill bit 3 includes a third-stage drill bit body 301 with a hollow interior. The third-stage drill bit body 301 is coaxially placed in the second-stage drill bit body 201. On the outside of the third-stage drill bit body 301, symmetrically arranged are first wing spring pins 302. The first wing spring pins 302 are slidably placed in the second-stage drill bit track groove 202;

[0087] The third-stage drill bit body 301 is threadedly connected to the head rotating pipe 5. The head rotating pipe 5 is also threadedly connected to the reducing pipe 4. The tail end of the head rotating pipe 5 is sequentially connected to several connecting rotating pipes 6. Inside the third-stage drill bit body 301, the head rotating pipe 5 and all the connecting rotating pipes 6, there is a snap component. The rotary joint 13 is connected to the last connecting rotating pipe 6 and the snap component. Rotating the rotary joint 13 drives the third-stage drill bit 3 to move back and forth in the second-stage drill bit 2.

[0088] The outer diameter of the first-stage drill bit body 101 is 130 mm, the outer diameter of the second-stage drill bit body 201 is 100 mm, and the outer diameter of the third-stage drill bit body 301 is 36 mm;

[0089] Refer to Figures 2-5, on the front end face of the first-stage drill bit pipe body 101, a plurality of first-stage drill bit tooth platforms 104 are distributed along the circumferential direction. On each first-stage drill bit tooth platform 104, a first-stage drill bit pick 105 is provided, and the outer diameter of the first-stage drill bit pick 105 is at least 5 mm greater than the outer diameter of the first-stage drill bit pipe body 101;

[0090] Refer to Figure 2 , Figure 6 and Figure 7 , on the front end face of the second-stage drill bit pipe body 201, a plurality of second-stage drill bit tooth platforms 205 are distributed along the circumferential direction. On each second-stage drill bit tooth platform 205, a second-stage drill bit pick 206 is provided, and the outer diameter of the second-stage drill bit pick 206 is smaller than the outer diameter of the second-stage drill bit tooth platform 205;

[0091] Refer to Figure 11 and Figure 12 , at the front end of the third-stage drill bit pipe body 301, a conical drill bit 304 is provided. On the conical drill bit 304, 4 top water outlet holes 305 are provided. One of the top water outlet holes 305 is located at the top end of the conical drill bit 304, and the remaining three are distributed at 120° on the circumferential surface of the conical drill bit 304, and these three top water outlet holes 305 are coplanar. On the third-stage drill bit pipe body 301, a plurality of outer water outlet holes 306 are also evenly opened along the circumferential direction;

[0092] The number of the first-stage drill bit rail grooves 102 is 2, which are symmetrically arranged inside the first-stage drill bit pipe body 101. The number of the pin holes 103 is 2, which are respectively located at the front ends of each drill bit rail groove;

[0093] The number of the second-stage drill bit spring pins 204 is 2, the number of the second-stage drill bit 2 tracks is 2, and the number of the first wing spring pins 302 is 2;

[0094] Each of the first wing spring pins 302 is connected to the first compression spring chamber 303, and the first compression spring chamber 303 is located inside the third-stage drill bit pipe body 301.

[0095] Refer to Figure 13 and Figure 14 , the end rotating pipe 5 includes a first rotating pipe 501, a first bearing 502 and a tail pipe 503. The tail end of the first rotating pipe 501 is rotatably connected to the tail pipe 503 through the first bearing 502. The tail end of the third-stage drill bit pipe body 301 is threadedly connected to the front end of the first rotating pipe 501 and they are both placed inside the second-stage drill bit 2. The front end of the tail pipe 503 is connected to the reduced-diameter pipe 4, and the tail end of the tail pipe 503 is successively connected with a plurality of connecting rotating pipes 6;

[0096] Refer to Figure 15 and Figure 16, the connecting and rotating pipe 6 includes an outer pipe body 601, a second bearing 602 and a second rotating pipe 603; the second rotating pipe 603 is located inside the outer pipe body 601 and they are coaxial. Both ends of the second rotating pipe 603 are rotatably connected to the outer pipe body 601 through the second bearing 602; the outer pipe bodies 601 and the second rotating pipes 603 of adjacent connecting and rotating pipes 6 are connected by threads respectively. The first second rotating pipe 603 is connected to the first rotating pipe 501 by threads, and the first outer pipe body 601 is connected to the tail pipe 503 by threads;

[0097] By rotating the rotary joint 13 clockwise or counterclockwise, all the second rotating pipes 603 and the first rotating pipes 501 are driven to rotate clockwise or counterclockwise, so as to drive the three-stage drill bit 3 to move forward or backward in the two-stage drill bit 2.

[0098] Refer to Figure 13 and Figure 14 , the front end of the tail pipe 503 is provided with an internal thread 5031 of the tail pipe for connecting with the reducing pipe 4, and the tail end of the tail pipe 503 is provided with an external thread 5032 of the tail pipe for connecting with the second rotating pipe 603 of the first connecting and rotating pipe 6;

[0099] The tail end of the three-stage drill bit pipe body 301 is provided with an external thread 308 of the three-stage drill bit. The front end of the first rotating pipe 501 is provided with a first internal thread 5011 for connecting with the external thread 308 of the three-stage drill bit. And two notches 5013 are symmetrically arranged at the front end of the first rotating pipe 501. The tail end of the first rotating pipe 501 is provided with a first external thread 5012; two first clamping holes 5014 are symmetrically arranged at the first external thread 5012.

[0100] Refer to Figure 15 and Figure 16 , the front end of the outer pipe body 601 of each connecting and rotating pipe 6 is provided with an internal thread 6011 of the outer pipe body. The internal thread 6011 of the outer pipe body of the first connecting and rotating pipe 6 is used for connecting with the external thread 5032 of the tail pipe. The tail end of the outer pipe body 601 is provided with an external thread 6012 of the outer pipe body for connecting with the internal thread 6011 of the outer pipe body of the adjacent connecting and rotating pipe 6; the front end of each second rotating pipe 603 is provided with a second internal thread 6031, and the tail end is provided with a second external thread 6032;

[0101] Two first clamping grooves 6033 are symmetrically arranged at the second internal thread 6031 of the second rotating pipe 603. The depth of the two first clamping grooves 6033 is 1 / 2 of the thickness of the second rotating pipe 603 and does not penetrate the pipe body of the second rotating pipe 603; two second clamping holes 6034 are symmetrically arranged at the second external thread 6032 of the second rotating pipe 603, and the second clamping holes 6034 penetrate the pipe body of the second rotating pipe 603;

[0102] The two first card slots 6033 on the second rotating tube 603 connected to the first rotating tube 6 correspond in position and size to the two first card holes 5014 on the first rotating tube 501, and the two first card slots 6033 on the remaining adjacent second rotating tubes 603 correspond in position and size to the two second card holes 6034.

[0103] Referring to Figure 17 , the buckle assembly includes a double buckle assembly 7 and a single buckle assembly 8. The double buckle assembly 7 is arranged inside the first rotating tube 501, and the single buckle assembly 8 is arranged inside each second rotating tube 603. The adjacent single buckle assemblies 8 are buckled and connected to each other. Each single buckle assembly 8 is clamped at the connection between its external second rotating tube 603 and the next second rotating tube 603 to connect the adjacent second rotating tubes 603; the first single buckle assembly 8 is buckled and connected to the double buckle assembly 7. One end of the double buckle assembly 7 is buckled and connected to the three-stage drill pipe body 301, and the other end is clamped at the connection between the first rotating tube 501 and the first second rotating tube 603 to connect the three-stage drill pipe body 301, the end rotating tube 5 and the first connecting rotating tube 6 together;

[0104] 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 inside the tail end of the three-stage drill pipe body 301. The bottoms of the two first buckles 701 are respectively connected to the first double-wing spring pin 703 through the first steel wire rope 702. The first double-wing spring pin 703 and the first steel wire rope 702 pass through the inside of the first rotating tube 501, and the first double-wing spring pin 703 is connected to the two first card holes 5014 on the first rotating tube 501;

[0105] The single buckle assembly 8 includes one 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 to 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;

[0106] Referring to Figure 18 , the first double-wing spring pin 703 and the second double-wing spring pin 803 have the same structure, and both include a second spring chamber 9, two second wing spring pins 10, an upper hanging ring 11 and a lower hanging ring 12. One second wing spring pin 10 is arranged on each of the left and right sides of the second spring chamber 9, and the upper hanging ring 11 and the lower hanging ring 12 are arranged at the upper and lower ends of the second spring chamber 9 respectively. 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 to the first buckle 701 or the second buckle 801.

[0107] The first buckle 701 and the second buckle 801 are O-shaped keychains.

[0108] Referring to Figures 8-10 As shown in the figure, the control component 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 communicating with the secondary drill bit track groove 202 is provided in front of the secondary drill bit track groove 202, and the cavity also communicates with 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. A connecting shaft 2032 is installed on the two connecting plates 2039. The connecting shaft 2032 slides in the slide rail 2034. A limit spring pin 2035 is also provided in the slide rail 2034. A connecting rod 2036 is provided outside the fixed platform 2033. A spring platform 2037 is provided on the connecting rod 2036. The spring platform 2037 is fixed on the inner wall of the cavity. The end of the connecting rod 2036 is fixed to the secondary drill bit spring pin 204. A spring 2038 is provided outside the connecting rod 2036 between the spring platform 2037 and the secondary drill bit spring pin 204; when the driving shaft 2031 is stressed, the driving shaft 2031 drives the connecting plate 2039 to move forward, thereby driving the connecting shaft 2032 to move obliquely upward along the slide rail 2034. At this time, the fixed platform 2033 together with the connecting rod 2036 moves away from the secondary drill bit spring pin 204, thereby driving the secondary drill bit spring pin 204 to compress the spring 2038 and retract along the pin hole 103 to the cavity side. When the connecting shaft 2032 moves above the limit spring pin 2035, the limit spring pin 2035 pops out to limit it.

[0109] Referring to Figure 19 As shown in the figure, the rotary joint 13 includes a square end 1301 and a joint pipe body 1302. The square end 1301 is a solid structure. A hollow joint pipe 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 pipe body 1302, which matches the second external thread 6032 of the last second rotary pipe 603. Two symmetrically arranged second card slots 1304 are provided at the third internal thread 1303. The positions and sizes of the two second card slots 1304 correspond to the two second card holes 6034 of the second rotary pipe 603;

[0110] Rotate the rotary joint 13 clockwise to drive all the second rotary pipes 603 and the first rotary pipe 501 to rotate clockwise. Through the thread between the end of the three-stage drill pipe body 301 and the first rotary pipe 501, control the two first wing spring pins 302 outside the three-stage drill pipe body 301 to move forward along the second-stage drill rail groove 202, thereby driving the control assembly 203 to act, controlling the two second-stage drill spring pins 204 of the second-stage drill pipe body 201 to retract, disengaging from the pin holes 103 of the first-stage drill pipe body 101, and being placed in the first-stage drill rail groove 102;

[0111] Rotate the rotary joint 13 counterclockwise to drive all the connecting rotary pipes 6 and the end rotary pipe 5 to rotate counterclockwise, so that the end rotary pipe 5 is disengaged from the three-stage drill pipe body 301. After disassembling the rotary joint 13, then pull the single snap component 8 inside the last connecting rotary pipe 6 backward to completely pull out all the single snap components 8, double snap components 7 and the three-stage drill 3 through the end rotary pipe 5 and the connecting rotary pipe 6.

[0112] Embodiment 2

[0113] This embodiment is illustrated by taking a 130mm large-diameter drilling for 20m and a 36mm small-diameter drilling for 35cm as examples.

[0114] Refer to Figures 1-19 , the usage method of the special multi-stage deformation drill for stress relief method in-situ stress measurement is realized by using the special multi-stage deformation drill for stress relief method in-situ stress measurement described in Embodiment 1, and specifically includes the following steps:

[0115] S1. Use a drill rig and a φ130mm drill bit to drill a 1m deep hole at the measurement location;

[0116] S2. Bit assembly: Withdraw the φ130mm drill bit and drill pipe, assemble the first-stage drill 1, second-stage drill 2, third-stage drill 3 and the end rotary pipe 5 together and put them into the hole, and adjust the position of the third-stage drill 3 by rotating the end rotary pipe 5 so that its front end protrudes 5mm from the front ends of the first-stage drill 1 and the second-stage drill 2;

[0117] In the step S2, the assembly of the first-stage drill 1, the second-stage drill 2 and the third-stage drill 3 is specifically as follows: First, install the diameter reducer on the tail pipe 503 of the end rotary pipe 5, and then connect the tail end of the three-stage drill pipe body 301 with the first rotary pipe 501 of the end rotary pipe 5 through a thread;

[0118] Before connection, first connect the two pull rings 307 below the three-stage drill pipe 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 rings 11 of the first double-wing spring pin 703. Then pass the first double-wing spring pin 703 and the first steel wire rope 702 through the end rotating pipe 5. (The length of the first steel wire rope 702 should be such that after the three-stage drill pipe body 301 is connected to the end rotating pipe 5, the first double-wing spring pin 703 can protrude outside the tail end of the end rotating pipe 5 by no less than 400 mm). Then, sleeve the two-stage drill pipe body 201 outside the three-stage drill pipe body 301, and place the two first wing spring pins 302 on the three-stage drill pipe body 301 at the bottom of the two-stage drill tracks 202 inside the two-stage drill pipe body 201. Then, sleeve the first-stage drill 1 outside the second-stage drill 2, so that the second-stage drill spring pin 204 outside the two-stage drill pipe body 201 is located in the pin hole 103 of the first-stage drill pipe body 101. After completion, adjust the position of the three-stage drill 3 by clockwise rotating the first rotating pipe 501 of the end rotating pipe 5, so that the tip of the conical drill bit 304 of the three-stage drill 3 protrudes 5 mm beyond the front ends of the first-stage drill 1 and the second-stage drill 2;

[0119] S3. Assembly of the drilling tool and drilling of a large-diameter borehole (the diameter of the large-diameter borehole is 130 mm): Install the double buckle assembly 7 in the three-stage drill 3 and the end rotating pipe 5, and use the drilling rig to connect the tail end of the end rotating pipe 5 to the first connecting rotating pipe 6, and snap the double buckle assembly 7 to the connecting rotating pipe 6. Then connect the water whip to the tail end of the first connecting rotating pipe 6 and start drilling;

[0120] Then remove the water whip, install the single buckle assembly 8 at the tail end of the double buckle assembly 7, and then use the drilling rig to connect the second connecting rotating pipe 6 at the tail end of the first connecting rotating pipe 6. After the connection is completed, snap the single buckle assembly 8 to the second connecting rotating pipe 6, install the water whip and continue drilling; Repeat this cycle until the drilling depth reaches the designed depth of 20 m to complete the drilling of the 130-mm large-diameter borehole;

[0121] S4. Drilling bit transformation and drilling with a small-diameter drill hole (the diameter of the small-diameter drill hole is 36 mm): Install the rotary joint 13 at the tail end of the last connecting rotary pipe 6, then retract the drill bit as a whole by 400 mm, and use a wrench to rotate the rotary joint 13 clockwise, so that the second rotary pipe 603 in all the connecting rotary pipes 6 and the first rotary pipe 501 in the end rotary pipe 5 rotate clockwise. At this time, under the combined action of the first wing spring pins 302 of the three-stage drill bit body 301 and the lower thread, the two first wing spring pins 302 of the three-stage drill bit body 301 will move forward along the inside of the two-stage drill bit body 201 to the forefront of the two-stage drill bit track groove 202. The two first wing spring pins 302 contact the control component 203 and trigger its action, causing the two two-stage drill bit spring pins 204 outside the two-stage drill bit body 201 to retract, disengage from the two pin holes 103 on the one-stage drill bit body 101, and be placed in the one-stage drill bit track groove 102;

[0122] 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 drill hole for drilling. The drilling depth of the three-stage drill bit 3 is 35 cm;

[0123] S5. Recovery of the three-stage drill bit 3: After the drilling of the small-diameter drill hole is completed, remove the water whip and connect the rotary joint 13. Rotate the rotary joint 13 counterclockwise. At this time, the three-stage drill bit 3 will move backward along the two-stage drill bit track groove 202 and keep rotating until the thread of the first rotary pipe 501 disengages from the three-stage drill bit 3. At this time, the two first wing spring pins 302 of the three-stage drill bit 3 are located in the two notches 5013 at the front end of the first rotary pipe 501; At this time, continuously pull the second double-wing spring pin 803 in the last connecting rotary pipe 6 backward, so that all the single snap components 8 and double snap components 7 move backward together, so that the three-stage drill bit 3 passes through the first rotary pipe 501 and all the second rotary pipes 603 in turn until the three-stage drill bit 3 is completely pulled out;

[0124] S6. Installation of the stress gauge: Inject the binder into the inner cavity of the stress gauge, install the hollow inclusion strain gauge into the predetermined position in the small-diameter drill hole after drilling through all the second rotary pipes 603 and the inside of the first rotary pipe 501 in turn, then squeeze the binder out of the inner cavity of the stress gauge into the space between the stress gauge and the small-diameter drill hole, and then wait for the binder inside the strain gauge to completely solidify, and firmly bond the stress gauge to the wall of the small-diameter drill hole;

[0125] S7. Stress relief drilling: Since the two two-stage drill bit spring pins 204 of the two-stage drill bit 2 have retracted, when the water whip is installed and drilled at this time, as the one-stage drill bit 1 continues to advance, the rock entering the inside will push the two-stage drill bit 2 to move backward along the one-stage drill bit track groove 102 until the stress relief experiment is completed. Record the strain values monitored by the stress gauge during the whole process;

[0126] S8. Drill withdrawal: Remove the connecting rotary pipe 6, the first-stage drill bit 1, the second-stage drill bit 2, and the third-stage drill bit 3 in sequence according to the normal drill withdrawal method.

[0127] The above content is only a preferred embodiment of the present invention. For those of ordinary skill in the art, many changes can be made in the specific implementation manners and application scopes according to the idea of the present invention. As long as these changes do not depart from the concept of the present invention, they all fall within 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 third-stage drill bit body is connected to the end rotating tube by threads, and the end rotating tube is also connected to the reducer by threads. The tail end of the end rotating tube is connected to several connecting rotating tubes in sequence. A buckle assembly is provided in the third-stage drill bit body, the end rotating tube, and all the connecting rotating tubes. The rotating joint is connected to the last connecting rotating tube and the buckle assembly. The rotating joint drives the third-stage drill bit to move forward and backward in the second-stage drill bit. 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 third-stage drill bit to move forward or backward in the second-stage drill bit; 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 provided on the left and right sides of the second compression spring chamber respectively, an upper hanging ring and a lower hanging ring are provided at the upper and lower ends of the second compression spring chamber respectively, the upper hanging ring is used to connect with 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; 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.

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 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.

4. 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.

5. 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 4, 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.

6. The method for using the special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 5, 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.

7. The method for using the special multi-stage deformable drilling tool for measuring ground stress by stress relief method as claimed in claim 5, 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.

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