A three-dimensional rock layer stress measurement system and method based on drilling deformation principle

Abstract

The present invention discloses a three-dimensional rock formation ground stress measurement system and method based on the drilling deformation principle, belonging to the field of ground stress measurement technology. The system includes a computing terminal, a leading device and a strain measuring device, the leading device includes a control mechanism arranged in a shell and an introduction mechanism arranged at the top of the shell; the strain measuring device includes an opening and closing radial strain measuring mechanism and an axial strain measuring mechanism, and the opening and closing radial strain measuring mechanism, the axial strain measuring mechanism and the introduction mechanism are all electrically connected to the control mechanism. At the same time, a method based on the above system is disclosed, which measures radial deformation and axial deformation by adopting an opening and closing radial strain measuring mechanism and an axial strain measuring mechanism, and the opening and closing radial strain measuring mechanism and the axial strain measuring mechanism are inserted into the test hole of the rock formation to be measured, which is not limited to the strength of the rock formation to be measured, and is applicable to both soft rock formations and hard rock formations, thereby expanding the scope of application and improving the measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field of ground stress measurement, and in particular to a three-dimensional ground stress measurement system and method for rock formations based on the borehole deformation principle. Background Art

[0002] Geostress is a natural stress formed in the strata during the geological history and is one of the most important properties of the strata. Various geological phenomena on the surface and inside the earth and their related physical and chemical processes are closely related to the action of geostress. Fully understanding and clarifying the geostress state in the strata is a necessary prerequisite for realizing scientific excavation design and decision-making in geotechnical engineering and safe and efficient development of energy resources. It is also the basis for solving scientific problems related to geodynamics such as plate driving mechanism, earth energy balance, earthquake mechanism, tectonic deformation, etc. Therefore, accurate geostress measurement in order to accurately determine the geostress state in the strata has extremely important scientific value and practical significance for geotechnical engineering construction and research on earth science issues.

[0003] In the prior art, the measurement of geostress only considers the influence of temperature. For example, the announcement number CN118243499B discloses a method for measuring the stress of a central borehole in a deep rock mass considering temperature and bedding tendency, which relates to the technical field of deep rock geostress measurement. It includes installing a laser displacement sensor, performing stress relief of the central borehole, calculating the magnitude and direction of the two principal stresses on the surface of the rock mass; decomposing the rock volume strain and correcting the rock volume strain through indoor cyclic loading and unloading tests; correcting the rock elastic modulus through indoor triaxial compression tests of rocks with different bedding tendencies; and recalculating and iterating the corrected data to obtain the magnitude and direction of the two principal stresses on the surface of the rock mass. Considering the problem of temperature influence, it is not affected by adjacent measuring points, the measurement difficulty is relatively small, and a relatively accurate rock mass stress can be obtained. However, in the actual measurement process, these methods are mainly aimed at (medium) hard rock masses, and their mechanical behavior is usually assumed to be linear elastic, isotropic and uniformly continuous. However, these assumptions do not conform to the actual situation of rocks. In fact, rock masses in nature are basically nonlinear, heterogeneous, and anisotropic, especially soft rocks have obvious creep characteristics and no longer follow the linear elastic law. As a result, existing geostress measurement methods are basically not applicable to soft rocks, and the measurement accuracy is poor or even the measurement results are invalid. Currently, there is no effective and reliable geostress measurement method for soft rocks. Therefore, there is a great practical need to develop a three-dimensional geostress measurement system that is applicable to both soft rocks and hard rock masses. Summary of the invention

[0004] The purpose of the present invention is to provide a three-dimensional rock stress measurement system and method based on the drilling deformation principle to solve the above technical problems.

[0005] To achieve the above object, the present invention provides a three-dimensional rock formation stress measurement system based on the drilling deformation principle, including a computing terminal, a pilot device and a strain measurement device, wherein the pilot device includes a control mechanism arranged in a housing and an introduction mechanism arranged at the top of the housing;

[0006] The strain measuring device comprises an opening and closing radial strain measuring mechanism and an axial strain measuring mechanism. The opening and closing radial strain measuring mechanism, the axial strain measuring mechanism and the introduction mechanism are all electrically connected to the control mechanism.

[0007] Preferably, the control mechanism includes a data recorder, a power supply battery and a controller, the data recorder and the power supply battery are electrically connected to the controller, and the data recorder is connected to the computing terminal.

[0008] Preferably, the introduction mechanism comprises a first synchronous telescopic member, the telescopic end of the first synchronous telescopic member is hinged to a guide plate via a torsion spring, and a plurality of balls and a pressure sensor are arranged on the outer side of the guide plate;

[0009] The first synchronous telescopic member and the pressure sensor are both electrically connected to the controller.

[0010] Preferably, the first synchronous telescopic member includes a rotary drive motor, which is fixed in the housing through a mounting plate, a driving gear is arranged on the output shaft of the rotary drive motor, the driving gear is meshed with a driven gear on the mounting plate, a circumferentially distributed fan-shaped swing groove is provided on the inner side of the mounting plate, the driven gear is connected to one end of a swing connecting rod arranged in the swing groove, a strip through hole is provided at the other end of the swing connecting rod, a driving column is arranged in the strip through hole, the driving column is arranged on the first telescopic rod, and the telescopic end of the first telescopic rod passes through the through hole of the housing and is hinged to the guide plate through a torsion spring;

[0011] The rotary drive motor is electrically connected to the controller.

[0012] Preferably, the opening and closing radial strain measuring mechanism comprises a hollow tube, a fixed hinge ring is arranged at one end of the hollow tube, the fixed hinge ring is connected to the shell through an extension rod, six first support rods are hinged on the circumferential side of the fixed hinge ring, a movable hinge ring is slidably arranged on the hollow tube, six second support rods are hinged on the circumferential side of the movable hinge ring, the second support rods are hinged to the first support rods, and a cantilever spring is fixed on the second support rod, and a radial strain gauge and a first temperature sensor are arranged on the cantilever spring; a plurality of track coils are arranged in the hollow tube, and a movable coil is arranged in the movable hinge ring;

[0013] The track coil and the moving coil are both electrically connected to the controller; the radial strain gauge and the first temperature sensor are both electrically connected to the data recorder.

[0014] Preferably, the axial strain measuring mechanism comprises a second synchronous telescopic member, and the telescopic end of the second synchronous telescopic member is provided with Spring plate, The second temperature sensor and the axial strain gauge are arranged on the spring plate. One end of the spring plate is fixed to the telescopic end of the second synchronous telescopic member. The other end of the spring plate is provided with a V-shaped groove for increasing the friction with the hole wall;

[0015] The axial strain gauge and the second temperature sensor are both electrically connected to the data recorder;

[0016] The second synchronous telescopic member is electrically connected to the controller.

[0017] Preferably, the second synchronous telescopic member comprises an annular drive motor, which is mounted on the movable hinge ring, and is connected to a drive disk, on which a circumferentially distributed arc guide groove is provided, in which a toggle column is provided, and the toggle column is connected to a second telescopic rod slidably arranged in the cross, and the cross is connected to the movable hinge ring through a connecting sleeve;

[0018] The annular driving motor is electrically connected to the controller.

[0019] A method for measuring three-dimensional ground stress of rock formations based on the principle of borehole deformation, the specific steps are as follows:

[0020] Step S1: drilling a test hole in the rock formation to be tested;

[0021] Step S2: installing the strain measuring device in the test hole through the leading device;

[0022] Step S3: stress relief is performed on the rock formation to be tested by drilling, and radial strain, axial strain and temperature data relative to the test point during the stress relief process are collected by a data recorder;

[0023] Step S4: Take out the strain measuring device and the leading device, transfer the data in the data recorder to the computing terminal, conduct a temperature calibration test on the core of the borehole to be measured, and use the strain data corrected by temperature calibration to calculate the size and direction of three-dimensional ground stress.

[0024] Preferably, step S2 is specifically as follows:

[0025] Step S21: insert the leading device into the quasi-test hole, and the ball of the guide plate contacts the inner wall of the test hole. When the shell enters the bottom of the test hole, start the first synchronous telescopic member to make the guide plate in a vertical state and attached to the inner wall of the test hole until the pressure sensor reaches the set value and stops;

[0026] Step S22: starting the open-and-close radial strain measuring mechanism, controlling the corresponding track coil and the moving coil through the controller so that the moving hinge ring moves along the hollow tube to the test position, so that the first support rod and the second support rod convert the cantilever spring from a vertical state to an inclined state, so that one end of the cantilever spring contacts the inner wall of the test hole;

[0027] Step S23: Start the axial strain measurement mechanism, drive the annular drive motor to rotate through the controller to drive the drive plate to rotate, so that the toggle column moves in the arc guide groove, so that the second telescopic rod extends outward, The V-shaped groove on the spring plate contacts the inner wall of the test hole.

[0028] Preferably, step S4 is specifically as follows:

[0029] Step S41: Obtain the diameter deformation at three angles in the radial direction of the drilling hole and the displacement change at four angles in the axial direction of the drilling hole:

[0030] ;

[0031] in, is the drilling deformation, for The diameter deformation in the direction, for The diameter deformation in the direction, for The diameter deformation in the direction, for The change in axial displacement in the direction, for The change in axial displacement in the direction, for The change in axial displacement in the direction, for The change of axial displacement in the direction;

[0032] Step S42: Divide the drilling deformation by the drilling diameter to obtain a dimensionless value ;

[0033] Step S43: obtaining stress value through observation equation;

[0034] The observation equation is as follows:

[0035] ;

[0036] in, E is the Young's modulus of the rock to be tested, is Poisson's ratio, for The distance between the contact point between the spring plate and the hole wall and the contact point between the cantilever spring and the hole wall, is the drilling diameter.

[0037] Therefore, the present invention adopts the above-mentioned three-dimensional rock stress measurement system and method based on the drilling deformation principle, which has the following beneficial effects: by adopting an open-and-closed radial strain measurement mechanism and an axial strain measurement mechanism to measure the radial deformation and axial deformation, and the open-and-closed radial strain measurement mechanism and the axial strain measurement mechanism are inserted into the test hole of the rock formation to be measured, the strength of the rock formation to be measured is not limited, and it is applicable to both soft rock formations and hard rock formations, thereby expanding the scope of application, improving the measurement accuracy, and the measurement operation is simple and convenient.

[0038] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a schematic diagram of the three-dimensional structure of a rock formation three-dimensional ground stress measurement system based on the drilling deformation principle of the present invention;

[0040] Figure 2 This is a side view of a rock formation three-dimensional ground stress measurement system based on the drilling deformation principle of the present invention;

[0041] Figure 3 This is a schematic structural diagram of the first synchronous telescopic member of the present invention;

[0042] Figure 4 It is a schematic diagram of the structure of the axial strain gauge of the present invention;

[0043] Figure 5 The present invention is a principle block diagram of a three-dimensional rock stress measurement system based on the drilling deformation principle.

[0044] Reference numerals

[0045] 1. Shell; 11. Extension rod; 2. Control mechanism; 21. Data recorder; 22. Power supply battery; 23. Controller; 3. Introduction mechanism; 31. First synchronous telescopic member; 311. Rotation drive motor; 312. Mounting plate; 313. Driving gear; 314. Driven gear; 315. Fan-shaped swing groove; 316. Swing connecting rod; 317. Strip through hole; 318. Driving column; 319. First telescopic rod; 32. Guide plate; 33. Ball; 34. Pressure sensor; 4. Opening and closing radial strain Measuring mechanism; 41, hollow tube; 42, fixed hinge ring; 43, first support rod; 44, movable hinge ring; 45, second support rod; 46, radial strain gauge; 47, first temperature sensor; 48, cantilever spring; 5, axial strain measuring mechanism; 51, second synchronous telescopic member; 511, annular drive motor; 512, drive disk; 513, arc guide groove; 514, toggle column; 515, cross; 516, second telescopic rod; 517, connecting sleeve; 52, second temperature sensor; 53, shaped spring plate; 531, V-shaped groove; 54, axial strain gauge. DETAILED DESCRIPTION

[0046] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the invented product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0048] like Figure 1-Figure 2 As shown, a three-dimensional rock stress measurement system based on the drilling deformation principle includes a computing terminal, a pilot device and a strain measurement device.

[0049] The leading device includes a control mechanism 2 arranged in the housing 1 and an introduction mechanism 3 arranged at the top of the housing 1. Figure 5As shown, the control mechanism 2 includes a data recorder 21, a power supply battery 22 and a controller 23. The data recorder 21 and the power supply battery 22 are both electrically connected to the controller 23, and the data recorder 21 is connected to a computing terminal.

[0050] The introduction mechanism 3 is used for introducing the subsequent strain measurement device. The introduction mechanism 3 includes a first synchronous telescopic member 31. The telescopic end of the first synchronous telescopic member 31 is hinged with a guide plate 32 through a torsion spring. A plurality of balls 33 and a pressure sensor 34 are arranged on the outer side of the guide plate 32. The first synchronous telescopic member 31 and the pressure sensor 34 are both electrically connected to the controller 23. Figure 3 As shown, the first synchronous telescopic member 31 includes a rotary drive motor 311, which is fixed in the shell 1 through a mounting plate 312. A driving gear 313 is arranged on the output shaft of the rotary drive motor 311, and the driving gear 313 is meshed with a driven gear 314 on the mounting plate 312. A circumferentially distributed fan-shaped swing groove 315 is provided on the inner side of the mounting plate 312. The driven gear 314 is connected to one end of a swing connecting rod 316 arranged in the swing groove. A strip through hole 317 is provided at the other end of the swing connecting rod 316. A driving column 318 is provided in the strip through hole 317. The driving column 318 is arranged on the first telescopic rod 319. The telescopic end of the first telescopic rod 319 passes through the through hole of the shell 1 and is hinged to the guide plate 32 through a torsion spring. The rotary drive motor 311 is electrically connected to the controller 23.

[0051] The strain measuring device includes an open-and-close radial strain measuring mechanism 4 and an axial strain measuring mechanism 5. The open-and-close radial strain measuring mechanism 4 includes a hollow tube 41, one end of which is provided with a fixed hinge ring 42, which is connected to the housing 1 through an extension rod 11, and the circumferential side of the fixed hinge ring 42 is hinged with six first support rods 43, a movable hinge ring 44 is slidably provided on the hollow tube 41, and the circumferential side of the movable hinge ring 44 is hinged with six second support rods 45, the second support rods 45 are hinged with the first support rods 43, and a cantilever spring 48 is provided on the second support rod 45, and a radial strain gauge 46 and a first temperature sensor 47 are fixed on the cantilever spring 48; a plurality of track coils are provided in the hollow tube 41, and a movable coil is provided in the movable hinge ring 44, and the track coil and the movable coil are both electrically connected to the controller 23; the radial strain gauge 46 and the first temperature sensor 47 are both electrically connected to the data recorder 21. The first temperature sensor 47 is used for temperature compensation.

[0052] The axial strain measuring mechanism 5 comprises a second synchronous telescopic member 51, and the telescopic end of the second synchronous telescopic member 51 is provided with Shaped spring plate 53, A second temperature sensor 52 and an axial strain gauge 54 are provided on the spring plate 53. Figure 4 As shown, One end of the spring plate 53 is fixed to the telescopic end of the second synchronous telescopic member 51. The other end of the spring plate 53 is provided with a V-shaped groove 531 for increasing the friction with the hole wall. Figure 1 Only one telescopic end is shown, and it is not fully extended. Figure 2 middle The spring plate 53 is in an extended state. The spring plate 53 is in contact with the test hole. The axial strain gauge 54 and the second temperature sensor 52 are both electrically connected to the data recorder 21, and the second synchronous telescopic member 51 is electrically connected to the controller 23. The second synchronous telescopic member 51 includes an annular drive motor 511, which is mounted on the movable hinge ring 44. The annular drive motor 511 is connected to a drive disk 512, and a circumferentially distributed arc guide groove 513 is provided on the drive disk 512. A toggle column 514 is provided in the arc guide groove 513. The toggle column 514 is connected to a second telescopic rod 516 slidably arranged in a cross 515. The cross 515 is connected to the movable hinge ring 44 through a connecting sleeve 517, and the annular drive motor 511 is electrically connected to the controller 23.

[0053] A method for measuring three-dimensional ground stress of rock formations based on the principle of borehole deformation, the specific steps are as follows:

[0054] Step S1: drilling a test hole in the rock formation to be tested.

[0055] Step S2: Install the strain measuring device in the test hole through the guide device.

[0056] Step S21: insert the leading device into the quasi-test hole, and the ball 33 of the guide plate 32 contacts the inner wall of the test hole. When the housing 1 enters the bottom of the test hole, the first synchronous telescopic member 31 is activated, so that the guide plate 32 is in a vertical state and attached to the inner wall of the test hole ( Figure 2 until the pressure sensor 34 reaches the set value and stops.

[0057] Step S22: Start the opening and closing radial strain measuring mechanism 4, and control the corresponding track coil and the moving coil through the controller 23 so that the moving hinge ring 44 moves along the hollow tube 41 to the test position, so that the first support rod 43 and the second support rod 45 convert the cantilever spring 48 from a vertical state to an inclined state, so that one end of the cantilever spring 48 contacts the inner wall of the test hole.

[0058] Step S23: Start the axial strain measuring mechanism 5, and drive the annular driving motor 511 to rotate through the controller 23 to drive the driving disk 512 to rotate, so that the toggle column 514 moves in the arc guide groove 513, so that the second telescopic rod 516 extends outward, so that The V-shaped groove 531 of the spring plate 53 contacts the inner wall of the testing hole.

[0059] Step S3: stress relief is performed on the rock formation to be tested by drilling, and radial strain, axial strain and temperature data relative to the test point during the stress relief process are collected by the data recorder 21 .

[0060] Step S4: Take out the strain measuring device and the leading device, transfer the data in the data recorder 21 to the computing terminal, perform a temperature calibration test on the core of the borehole to be measured, and use the strain data corrected by temperature calibration for three-dimensional geostress calculation.

[0061] Step S4 is specifically as follows:

[0062] Step S41: Obtain the diameter deformation at three angles in the radial direction of the drilling hole and the displacement change at four angles in the axial direction of the drilling hole:

[0063] ;

[0064] in, is the drilling deformation, for The diameter deformation in the direction, for The diameter deformation in the direction, for The diameter deformation in the direction, for The change in axial displacement in the direction, for The change in axial displacement in the direction, for The change in axial displacement in the direction, for The change in axial displacement in the direction.

[0065] Step S42: Divide the drilling deformation by the drilling diameter to obtain a dimensionless value .

[0066] Step S43: Obtain the stress value through the observation equation, the observation equation is as follows:

[0067] ;

[0068] in, E is the Young's modulus of the rock to be tested, is Poisson's ratio, for The distance between the contact point between the spring plate and the hole wall and the contact point between the cantilever spring and the hole wall, is the drilling diameter.

[0069] In order to verify the effectiveness of the technical solution of the present application, indoor ground stress simulation measurement tests were carried out on rocks with different hardnesses, and the sensitivity of the strain gauges used is shown in Table 1.

[0070] Table 1 Strain gauge sensitivity (microstrain data for 1 mm displacement, unit: με)

[0071] ;

[0072] The results of indoor ground stress simulation measurement tests for soft rock are shown in Table 2.

[0073] Table 2 Comparison of applied stress and calculated stress in indoor in-situ stress simulation measurement test for soft rock

[0074] ;

[0075] The test results of indoor ground stress simulation measurement for hard rock are shown in Table 3.

[0076] Table 3 Comparison of applied stress and calculated stress in indoor geostress simulation measurement test for hard rock mass

[0077] ;

[0078] The comparison data of the applied stress magnitude and direction and the calculated principal stress magnitude and direction are shown in Table 4. The stress direction is 0° from due north to due east and 360° from due north to due north again. The stress inclination is based on the horizontal plane, and the angle with the horizontal plane is positive when it is upward and negative when it is downward.

[0079] Table 4 Comparison of the magnitude and direction of applied stress and the magnitude and direction of calculated principal stress

[0080] ;

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A three-dimensional rock stress measurement system based on the drilling deformation principle, including a computing terminal, characterized in that: It also includes a leading device and a strain measuring device, wherein the leading device includes a control mechanism disposed in the housing and an introduction mechanism disposed at the top end of the housing; The strain measuring device comprises an opening and closing radial strain measuring mechanism and an axial strain measuring mechanism, and the opening and closing radial strain measuring mechanism, the axial strain measuring mechanism and the introduction mechanism are all electrically connected to the control mechanism; The introduction mechanism comprises a first synchronous telescopic member, the telescopic end of the first synchronous telescopic member is hinged with a guide plate through a torsion spring, and a plurality of balls and a pressure sensor are arranged on the outer side of the guide plate; The first synchronous telescopic member includes a rotary drive motor, which is fixed in the housing through a mounting plate, a driving gear is arranged on the output shaft of the rotary drive motor, the driving gear is meshed with a driven gear on the mounting plate, a circumferentially distributed fan-shaped swing groove is provided on the inner side of the mounting plate, the driven gear is connected to one end of a swing connecting rod arranged in the swing groove, a strip through hole is provided at the other end of the swing connecting rod, a driving column is arranged in the strip through hole, the driving column is arranged on the first telescopic rod, and the telescopic end of the first telescopic rod passes through the through hole of the housing and is hinged to the guide plate through a torsion spring; The opening and closing radial strain measuring mechanism comprises a hollow tube, a fixed hinge ring is arranged at one end of the hollow tube, the fixed hinge ring is connected to the shell through an extension rod, six first support rods are hinged on the circumferential side of the fixed hinge ring, a movable hinge ring is slidably arranged on the hollow tube, six second support rods are hinged on the circumferential side of the movable hinge ring, the second support rods are hinged to the first support rods, and a cantilever spring is fixed on the second support rod, and a radial strain gauge and a first temperature sensor are arranged on the cantilever spring; a plurality of track coils are arranged in the hollow tube, and a movable coil is arranged in the movable hinge ring; The axial strain measurement mechanism includes a second synchronous telescopic member, a π-shaped spring plate is provided at the telescopic end of the second synchronous telescopic member, a second temperature sensor and an axial strain gauge are provided on the π-shaped spring plate, one end of the π-shaped spring plate is fixed at the telescopic end of the second synchronous telescopic member, and the other end of the π-shaped spring plate is provided with a V-shaped groove for increasing friction with the hole wall.

2. The three-dimensional rock stress measurement system based on the drilling deformation principle according to claim 1 is characterized by: The control mechanism comprises a data recorder, a power supply battery and a controller. The data recorder and the power supply battery are both electrically connected to the controller, and the data recorder is connected to a computing terminal.

3. The three-dimensional rock stress measurement system based on the drilling deformation principle according to claim 2 is characterized by: The first synchronous telescopic member and the pressure sensor are both electrically connected to the controller.

4. The three-dimensional rock stress measurement system based on the drilling deformation principle according to claim 3 is characterized by: The rotary drive motor is electrically connected to the controller.

5. The three-dimensional rock stress measurement system based on the drilling deformation principle according to claim 4 is characterized in that: The track coil and the moving coil are both electrically connected to the controller; the radial strain gauge and the first temperature sensor are both electrically connected to the data recorder.

6. The three-dimensional rock stress measurement system based on the drilling deformation principle according to claim 5 is characterized by: The axial strain gauge and the second temperature sensor are both electrically connected to the data recorder; The second synchronous telescopic member is electrically connected to the controller.

7. The three-dimensional rock stress measurement system based on the drilling deformation principle according to claim 6 is characterized by: The second synchronous telescopic member includes an annular drive motor, which is mounted on the movable hinge ring and connected to a drive disk. The drive disk is provided with arc guide grooves distributed circumferentially, and a toggle column is arranged in the arc guide groove. The toggle column is connected to a second telescopic rod slidably arranged in the cross, and the cross is connected to the movable hinge ring through a connecting sleeve. The annular driving motor is electrically connected to the controller.

8. A method for measuring three-dimensional ground stress of rock formations based on the principle of borehole deformation, using a three-dimensional ground stress measurement system for rock formations based on the principle of borehole deformation as claimed in claim 7, characterized in that: The specific steps are as follows: Step S1: drilling a test hole in the rock formation to be tested; Step S2: installing the strain measuring device in the test hole through the leading device; Step S3: stress relief is performed on the rock formation to be tested by drilling, and radial strain, axial strain and temperature data relative to the test point collected during the stress relief process are collected by a data recorder; Step S4: Take out the strain measuring device and the leading device, transfer the data in the data recorder to the computing terminal, conduct a temperature calibration test on the core of the borehole to be measured, and use the strain data corrected by temperature calibration to calculate the size and direction of three-dimensional ground stress.

9. The method for measuring three-dimensional rock stress based on the drilling deformation principle according to claim 8, characterized in that: Step S2 is specifically as follows: Step S21: insert the leading device into the quasi-test hole, and the ball of the guide plate contacts the inner wall of the test hole. When the shell enters the bottom of the test hole, the first synchronous telescopic member is started, and the guide plate is in a vertical state and attached to the inner wall of the test hole until the pressure sensor reaches the set value and stops; Step S22: starting the open-and-close radial strain measuring mechanism, controlling the corresponding track coil and the moving coil through the controller so that the moving hinge ring moves along the hollow tube to the test position, so that the first support rod and the second support rod convert the cantilever spring from a vertical state to an inclined state, so that one end of the cantilever spring contacts the inner wall of the test hole; Step S23: start the axial strain measurement mechanism, drive the annular drive motor to rotate through the controller to drive the drive disk to rotate, so that the toggle column moves in the arc guide groove, the second telescopic rod extends outward, and the V-shaped groove of the π-shaped spring plate contacts the inner wall of the test hole.

10. The method for measuring three-dimensional rock stress based on the drilling deformation principle according to claim 9, characterized in that: Step S4 is specifically as follows: Step S41: Obtain the diameter deformation at three angles in the radial direction of the drilling hole and the displacement change at four angles in the axial direction of the drilling hole: in, is the drilling deformation, for The diameter deformation in the direction, for The diameter deformation in the direction, for The diameter deformation in the direction, for The change in axial displacement in the direction, for The change in axial displacement in the direction, for The change in axial displacement in the direction, for The change of axial displacement in the direction; Step S42: Divide the drilling deformation by the drilling diameter to obtain a dimensionless value ; Step S43: Obtain stress value through observation equation; The observation equation is as follows: in, E is the Young's modulus of the rock to be tested, is Poisson's ratio, is the distance between the contact point between the π-shaped spring plate and the hole wall and the contact point between the cantilever spring and the hole wall, is the drilling diameter.

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