Test device and method for measuring in-situ stress by simulated in-situ stress relief method

Abstract

The present invention discloses a test device and method for measuring in-situ stress by the simulated in-situ stress relief method, belonging to the technical field of test equipment. The device includes a combined visualization mechanism, an environment simulation mechanism, an operation mechanism, and a control mechanism. At the same time, a method based on the above test device for measuring in-situ stress by the simulated in-situ stress relief method is disclosed. By using the above test device and method for measuring in-situ stress by the simulated in-situ stress relief method, a strain gauge installation unit is provided, which is suitable for the installation of various types of strain gauges. The test hole cleaning unit uses scraping, blowing, and suction methods to clean the hole wall, and dries the hole wall while cleaning to avoid affecting the subsequent bonded connection. Moreover, the hole diameter is detected, so that the subsequent glue filling can be set according to the hole diameter, improving the effectiveness of filling. The CT imaging device and the scanning acoustic imaging device are added, realizing the visualization of the entire test process and providing more image data for subsequent stress analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of test equipment, and in particular to a test device and method for measuring in-situ stress by simulating the in-situ stress relief method. Background Art

[0002] The stress relief method is a measurement method for directly measuring the in-situ stress in rock masses. By drilling holes and installing strain gauges to monitor the deformation of the rock in its natural state, and then releasing the stress in a local area by means such as cutting or heating, the observed deformation changes can be used to calculate the magnitude and direction of the in-situ stress at that location.

[0003] After retrieval, the patent with the publication number CN105092105B discloses a test device for the local contact method of deep in-situ stress, which is provided with a drilling mechanism, a cleaning mechanism and a testing mechanism, and works in sequence to achieve characteristics such as miniaturization, intelligence and modularization. However, in actual application, there are still the following problems:

[0004] (1) During actual detection, for GSIR triaxial strain gauges, CSIRO hollow inclusion strain gauges, UNSW solid inclusion strain gauges, etc., they all need to be fixed by gluing. The method of directly inserting with a telescopic structure in the prior art is only applicable to USBM borehole strain gauges, but has a large error for non-uniform rock masses, resulting in low measured accuracy.

[0005] (2) The cleaning mechanism uses the method of water washing, but excessive humidity will also affect subsequent detection, and at the same time will also affect the subsequent installation of strain gauges.

[0006] (3) There is no visualization device, making it impossible to obtain image data during the stress relief process. Summary of the Invention

[0007] The purpose of the present invention is to provide a test device and method for measuring in-situ stress by simulating the in-situ stress relief method, and solve the above technical problems.

[0008] To achieve the above purpose, the present invention provides a test device for measuring in-situ stress by simulating the in-situ stress relief method, including,

[0009] A combined visualization mechanism for collecting internal images of the specimen throughout the process;

[0010] An environment simulation mechanism, which includes a confining pressure application unit and a temperature adjustment unit, for simulating the confining pressure and temperature environment of the specimen;

[0011] An operating mechanism for drilling test holes, relieving stress, cleaning test holes and installing strain gauges;

[0012] A control mechanism is used to control a combined visualization mechanism, an environmental simulation mechanism, and an operating mechanism, and to collect and display the data of the environmental simulation mechanism and strain gauges in real time.

[0013] Preferably, the combined visualization mechanism includes a CT imaging device and a scanning acoustic imaging device;

[0014] The CT imaging device includes a bracket, on which two mounting side plates are provided. A transmitter and a detector are connected by a lifter on the two mounting side plates, and a turntable is provided in the middle of the bracket;

[0015] The scanning acoustic imaging device includes a number of ultrasonic transducers and a number of relatively arranged receivers, and both the ultrasonic transducers and the receivers are connected to an acoustic wave analyzer;

[0016] The turntable, the transmitter, the detector, and the acoustic wave analyzer are all electrically connected to the control mechanism.

[0017] Preferably, the confining pressure applying unit includes an L-shaped fixing plate and two pressing plates. Both of the two pressing plates are connected with pressing hydraulic cylinders. The two pressing plates and the L-shaped fixing plate form a frame structure. Pressure sensors are provided on the two pressing plates. The L-shaped fixing plate and the pressing hydraulic cylinders are both fixed on the turntable. Through holes are provided on the L-shaped fixing plate and one of the pressing plates. Lifting mounting plates are arranged in the through holes. The ultrasonic transducers and the receivers are respectively installed on the two lifting mounting plates. A tightening member is provided on one side of the lifting mounting plate. The tightening member includes a top ball, which is connected to one end of a tightening spring, and the other end of the tightening spring is arranged in a blind hole of the lifting mounting plate;

[0018] The lifting mounting plates, the pressing hydraulic cylinders, and the pressure sensors are all electrically connected to the control mechanism.

[0019] Preferably, the temperature regulating unit includes a lower heating plate arranged on the turntable, and side heating plates and temperature detection optical fibers are arranged on the inner sides of the L-shaped fixing plate and the other pressing plate. The lower heating plate, the side heating plates, and the temperature detection optical fibers are all electrically connected to the control mechanism.

[0020] Preferably, the operating mechanism includes a rotating bracket, on which a drilling test hole unit, a test hole cleaning unit, a strain gauge mounting unit, and a stress relief unit are respectively arranged;

[0021] The rotating bracket, the drilling test hole unit, the test hole cleaning unit, the strain gauge mounting unit, and the stress relief unit are all electrically connected to the control mechanism.

[0022] Preferably, a cross mounting frame is provided at the top of the rotating bracket. The drilling test hole unit, the test hole cleaning unit, the strain gauge mounting unit, and the stress relief unit are respectively installed at the four extending ends of the cross mounting frame. The cross mounting frame is connected with a rotary drive motor, and the rotary drive motor is installed on the rotating bracket and is electrically connected to the control mechanism.

[0023] Preferably, the drilling test hole unit includes a first lifting hydraulic cylinder, and a drilling machine is arranged at the telescopic end of the first lifting hydraulic cylinder; the stress relief unit includes a second lifting hydraulic cylinder, and a thin-walled sleeve hole drilling machine is arranged at the telescopic end of the second lifting hydraulic cylinder;

[0024] The first lifting hydraulic cylinder, the drilling machine, the second lifting hydraulic cylinder, and the thin-walled sleeve hole drilling machine are all electrically connected to the control mechanism.

[0025] Preferably, the test hole cleaning unit includes a rotating tube, and two telescopic scraping plates are symmetrically arranged on the outer side of the rotating tube. The two telescopic scraping plates are arranged in the grooves on the outer side of the rotating tube through springs. The two telescopic scraping plates divide the rotating tube into a cleaning side and a detection side. A blowing port is arranged in the lower half of the cleaning side. A filter screen is arranged at the blowing port. Dust suction ports are arranged on the upper plate part of the cleaning side and the detection side. The dust suction ports are connected to the dust suction pipe inside the rotating tube through a communicating pipe. The rotating tube and the dust suction pipe are connected to a vacuum cleaner through a multi-channel rotary joint. The rotating tube is communicated with the air outlet pipe of the vacuum cleaner, and the dust suction pipe is communicated with the air inlet pipe of the vacuum cleaner; a heater is arranged on the air inlet pipe, and at least one row of distance detection sensors is arranged on the detection side; the rotating tube is arranged at one end of a ball spline. The ball spline is connected to a cleaning drive motor through a belt. The cleaning drive motor is installed on a cross mounting frame. The cleaning drive motor is connected to a lifting gear rack assembly through a bevel gear set and a chain. The gear in the lifting gear rack assembly and the bevel gear set are arranged on the cross mounting frame;

[0026] The cleaning drive motor, the vacuum cleaner, the distance detection sensor, and the heater are all electrically connected to the control mechanism.

[0027] Preferably, the strain gauge installation unit includes an installation sleeve. The installation sleeve is hollow, and a plurality of glue outlet ports are arranged at the open end of the installation sleeve. A vacuum suction cup is arranged inside the installation sleeve. The vacuum suction cup is connected to an air pump through an air pipe. The installation sleeve is installed at one end of a rotating spline. The other end of the rotating spline is installed on a cross mounting frame through a lifting cylinder. The rotating spline is connected to an installation drive motor through a belt. The installation drive motor is installed on the cross mounting frame. The spline shaft of the rotating spline is a hollow shaft. The hollow shaft is connected to a glue supply pump and an air pump through a multi-channel rotary joint. The installation sleeve and the air pipe are both connected to the multi-channel rotary joint; a plugging assembly is arranged at the bottom of the turntable. The plugging assembly includes a plugging motor, and a plugging plate is arranged on the output shaft of the plugging motor;

[0028] The plugging motor, the glue supply pump, the air pump, the lifting cylinder, and the installation drive motor are all electrically connected to the control mechanism.

[0029] Based on the above method of a test device for measuring in-situ stress by the simulated in-situ stress relief method, the specific steps are as follows:

[0030] Step S1: Prepare a specimen, place the specimen on the turntable, and arrange strain gauges on the surface of the specimen according to the test requirements to form a strain measurement and acquisition mechanism on the specimen surface;

[0031] Step S2: Start the confining pressure unit to place the specimen in the test position, start the CT imaging device to collect the initial specimen image, and then start the scanning acoustic imaging device to collect the initial acoustic wave of the specimen;

[0032] Step S3: Start the rotary drive motor to set the drill test hole unit opposite to the specimen, and start the first lifting hydraulic cylinder and the drilling machine to drill a test hole with a diameter in the range of 20 - 50 mm at the center of the specimen;

[0033] After drilling the test hole, start the rotary drive motor to set the test hole cleaning unit opposite to the specimen, start the vacuum cleaner, heater and cleaning drive motor in the test hole cleaning unit. Under the action of the ball spline, the rotating tube rotates and descends into the test hole to scrape pumice on the hole wall of the test hole, flush the hole wall and vacuum the dust; at the same time, detect the hole diameter through the distance detection sensor;

[0034] After cleaning the test hole, start the rotary drive motor to set the strain gauge installation unit opposite to the specimen, the lifting cylinder drives the installation sleeve to descend to the bottom of the test hole, start the plugging motor to set the plugging plate opposite to the test hole, release the vacuum suction cup by controlling the air pump, so that the strain gauge is placed on the plugging plate under the action of gravity, ensure that the strain gauge is installed at the central position of the test hole, start the installation drive motor to drive the installation sleeve to rotate, and at the same time start the glue supply pump and the lifting cylinder, so that the bonding glue inside the installation sleeve flows into the gap between the strain gauge and the test hole in a spiral manner; regulate the rotation speed of the installation drive motor and the lifting speed of the lifting cylinder according to the test hole diameter measured in Step S4;

[0035] After the bonding glue is cured, start the CT imaging device to collect the specimen image before the test, and then start the scanning acoustic imaging device to collect the acoustic wave of the specimen before the test;

[0036] Step S7: Start the temperature adjustment unit to heat the specimen until the set test temperature is reached, and after heating, start the pressure application hydraulic cylinder until the set confining pressure is reached;

[0037] Step S8: Start the rotary drive motor to set the stress relief unit opposite to the specimen. Start the second lifting hydraulic cylinder and the thin-wall sleeve hole drill to drill a relief hole concentric with the test hole. The diameter of the relief hole ranges from 110 to 160 mm to separate the core around the strain gauge from the specimen, thereby achieving stress relief. At the same time, collect the specimen image in real time through the CT imaging device, and collect the data of the strain gauge and strain meter in real time to obtain the data of the stress change on the specimen surface and the stress change inside the specimen. During the stress relief process, collect the specimen acoustic wave regularly. The process of collecting the specimen acoustic wave is as follows:

[0038] Turn off the CT imaging device, the second lifting hydraulic cylinder and the thin-wall sleeve hole drill. Raise the lifting mounting plate so that the ultrasonic transducer and receiver are set opposite to the specimen. Start the ultrasonic transducer and receiver to collect acoustic waves. After the collection is completed, lower the lifting mounting plate and start the CT imaging device, the second lifting hydraulic cylinder and the thin-wall sleeve hole drill to continue stress relief until the stress relief is completed.

[0039] Therefore, the test device and method for measuring in-situ stress by simulating the in-situ stress relief method of the present invention have the following beneficial effects:

[0040] (1) A strain gauge installation unit is provided, which is used to install the strain gauge by bonding. When installing the strain gauge, the adhesive extruded by the installation sleeve fills the gap between the strain gauge and the test hole in a spiral manner, which is suitable for the installation of many types of strain gauges.

[0041] (2) The test hole cleaning unit cleans the hole wall by scraping, blowing and sucking, and dries the hole wall during cleaning to avoid affecting the subsequent bonding connection. And the hole diameter is detected, so that the subsequent glue filling is set according to the hole diameter, improving the filling effectiveness.

[0042] (3) The CT imaging device and the scanning acoustic wave imaging device are added to realize the visualization of the test process and provide more image data for subsequent stress analysis.

[0043] Next, through the drawings and embodiments, the technical solutions of the present invention will be further described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic structural diagram of a test device for measuring in-situ stress by simulating the in-situ stress relief method of the present invention;

[0045] Figure 2 It is a schematic structural diagram of the environmental simulation mechanism of the present invention;

[0046] Figure 3 It is a schematic structural diagram of the installation lifting plate of the present invention;

[0047] Figure 4 Schematic diagram of the pressing member structure of the present invention;

[0048] Figure 5 Schematic diagram of the test hole cleaning unit structure of the present invention;

[0049] Figure 6 Schematic diagram of the rotating tube structure of the present invention;

[0050] Figure 7 Cross-sectional view of the rotating tube of the present invention;

[0051] Figure 8 Schematic diagram of the strain gauge installation unit structure of the present invention.

[0052] Reference numerals

[0053] 1. Control mechanism; 2. CT imaging device; 21. Bracket; 22. Installation side plate; 23. Lift; 24. Transmitter; 25. Detector; 26. Turntable; 3. Scanning acoustic imaging device; 31. Ultrasonic transducer; 32. Receiver; 33. Acoustic wave analyzer; 4. Confining pressure application unit; 41. L-shaped fixing plate; 42. Pressing plate; 43. Pressing hydraulic cylinder; 44. Pressure sensor; 45. Through hole; 46. Lifting installation plate; 47. Top ball; 48. Pressing spring; 5. Temperature regulation unit; 51. Lower heating plate; 52. Side heating plate; 53. Temperature detection optical fiber; 6. Rotating bracket; 61. Cross-shaped mounting bracket; 62. Rotating drive motor; 7. Drilling test hole unit; 71. First lifting hydraulic cylinder; 72. Drilling machine; 8. Stress relief unit; 81. Second lifting hydraulic cylinder; 82. Thin-walled sleeve hole drilling machine; 9. Test hole cleaning unit; 91. Rotating tube; 92. Telescopic scraper; 93. Spring; 94. Air outlet; 95. Dust suction port; 96. Connecting pipe; 97. Dust suction pipe; 98. Vacuum cleaner; 99. Heater; 910. Distance detection sensor; 911. Cleaning drive motor; 912. Lifting gear rack assembly; 10. Strain gauge installation unit; 101. Installation sleeve; 102. Glue outlet; 103. Vacuum chuck; 104. Air pump; 105. Lifting cylinder; 106. Installation drive motor; 107. Glue supply pump; 108. Sealing motor; 109. Sealing plate; 11. Ball spline. Detailed implementation manners

[0054] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the inventive product is customarily placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected" 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 directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside 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.

[0055] The following will describe the embodiments of the present invention in detail with reference to the drawings.

[0056] As Figure 1 shown, a test device for measuring in-situ stress by the simulated in-situ stress relief method includes a combined visualization mechanism, an environment simulation mechanism, an operating mechanism, and a control mechanism 1. The combined visualization mechanism, the environment simulation mechanism, and the operating mechanism are all electrically connected to the control mechanism 1.

[0057] The combined visualization mechanism is used to collect internal images of the whole process of the specimen. The combined visualization mechanism includes a CT imaging device 2 and a scanning acoustic imaging device 3. The CT imaging device 2 includes a bracket 21. There are two mounting side plates 22 on the bracket 21. A transmitter 24 and a detector 25 are connected by a lifter 23 on the two mounting side plates 22. A turntable 26 is arranged in the middle of the bracket 21. The scanning acoustic imaging device 3 includes a plurality of ultrasonic transducers 31 and a plurality of receivers 32 arranged oppositely. The ultrasonic transducers 31 and the receivers 32 are all connected to an acoustic wave analyzer 33. The turntable 26, the transmitter 24, the detector 25, and the acoustic wave analyzer 33 are all electrically connected to the control mechanism 1.

[0058] The environment simulation mechanism includes a confining pressure application unit 4 and a temperature adjustment unit 5, which are used to simulate the confining pressure and temperature environment of the specimen. As Figure 2 shown, the confining pressure application unit 4 includes an L-shaped fixing plate 41 and two pressing plates 42. Two pressing plates 42 are both connected with a pressing hydraulic cylinder 43. The two pressing plates 42 and the L-shaped fixing plate 41 form a frame structure. Pressure sensors 44 are arranged on the two pressing plates 42. The L-shaped fixing plate 41 and the pressing hydraulic cylinder 43 are both fixed on the turntable 26. The L-shaped fixing plate 41 and one of the pressing plates 42 are both provided with through holes 45. A lifting mounting plate 46 is arranged in the through hole 45. AsFigures 3 - 4 As shown, two lifting mounting plates 46 are respectively installed with ultrasonic transducers 31 and receivers 32. A tightening member is arranged on one side of the lifting mounting plate 46. The tightening member includes a top ball 47. The top ball 47 is connected to one end of a tightening spring 9348, and the other end of the tightening spring 9348 is arranged in a blind hole of the lifting mounting plate 46. The lifting mounting plate 46, the pressure-applying hydraulic cylinder 43, and the pressure sensor 44 are all electrically connected to the control mechanism 1. When performing a CT inspection, the lifting mounting plate 46 descends, so that the upper half of the lifting mounting plate 46 is set and continues to be supported in the through hole 45, avoiding the ultrasonic transducer 31 and the receiver 32 from affecting the CT inspection. When clamping a specimen, the lifting mounting plate 46 is located within the turntable 26, avoiding interfering with the movement of the pressure-applying plate 42.

[0059] The temperature adjustment unit 5 includes a lower heating plate 51 arranged on the turntable 26. Side heating plates 52 and temperature detection optical fibers 53 are arranged on the inner sides of the L-shaped fixing plate 41 and another pressure-applying plate 42. The lower heating plate 51, the side heating plates 52, and the temperature detection optical fibers 53 are all electrically connected to the control mechanism 1, used to simulate the temperature environment where the specimen is located, and at the same time, the temperature of the specimen can also be measured in real time.

[0060] An operating mechanism is used for drilling test holes, stress relief, cleaning test holes, and installing strain gauges. The operating mechanism includes a rotating bracket 6. A test hole drilling unit 7, a test hole cleaning unit 9, a strain gauge installation unit 10, and a stress relief unit 8 are respectively arranged on the rotating bracket 6. The rotating bracket 6, the test hole drilling unit 7, the test hole cleaning unit 9, the strain gauge installation unit 10, and the stress relief unit 8 are all electrically connected to the control mechanism 1.

[0061] A cross mounting frame 61 is arranged at the top of the rotating bracket 6. The test hole drilling unit 7, the test hole cleaning unit 9, the strain gauge installation unit 10, and the stress relief unit 8 are respectively installed at the four extension ends of the cross mounting frame 61. The cross mounting frame 61 is connected with a rotation drive motor 62. The rotation drive motor 62 is installed on the rotating bracket 6 and is electrically connected to the control mechanism 1, used to adjust the positions of each unit.

[0062] The test hole drilling unit 7 includes a first lifting hydraulic cylinder 71, and a drilling machine 72 is arranged at the telescopic end of the first lifting hydraulic cylinder 71; the stress relief unit 8 includes a second lifting hydraulic cylinder 81, and a thin-walled sleeve hole drilling machine 82 is arranged at the telescopic end of the second lifting hydraulic cylinder 81. The first lifting hydraulic cylinder 71, the drilling machine 72, the second lifting hydraulic cylinder 81, and the thin-walled sleeve hole drilling machine 82 are all electrically connected to the control mechanism 1.

[0063] As Figures 5 - 7As shown in the figure, the test hole cleaning unit 9 includes a rotating tube 91. Two telescopic scraping plates 92 are symmetrically arranged on the outer side of the rotating tube 91. The two telescopic scraping plates 92 are arranged in the grooves on the outer side of the rotating tube 91 through springs 93. The two telescopic scraping plates 92 divide the rotating tube 91 into a cleaning side and a detection side. A blowing port 94 is arranged in the lower half of the cleaning side. A filter screen is arranged at the blowing port 94. Dust suction ports 95 are arranged on the upper plate part of the cleaning side and the detection side. The dust suction ports 95 are connected to a dust suction tube 97 inside the rotating tube 91 through a communication pipe 96. The rotating tube 91 and the dust suction tube 97 are connected to a vacuum cleaner 98 through a multi-channel rotary joint. The rotating tube 91 is communicated with the air outlet pipe of the vacuum cleaner 98, and the dust suction tube 97 is communicated with the air inlet pipe of the vacuum cleaner 98. A heater 99 is arranged on the air inlet pipe. At least one row of distance detection sensors 910 is arranged on the detection side. The rotating tube 91 is arranged at one end of a ball spline 11. The ball spline 11 is connected to a cleaning drive motor 911 through a belt. The cleaning drive motor 911 is installed on a cross mounting bracket 61. The cleaning drive motor 911 is connected to a lifting gear rack assembly 912 through a bevel gear set and a chain. The gear in the lifting gear rack assembly 912 and the bevel gear set are arranged on the cross mounting bracket 61. The cleaning drive motor 911, the vacuum cleaner 98, the distance detection sensors 910 and the heater 99 are all electrically connected to a control mechanism 1.

[0064] As Figure 8 shown, the strain gauge mounting unit 10 includes a mounting sleeve 101. The mounting sleeve 101 is hollow, and a plurality of glue outlet ports 102 are arranged at the open end of the mounting sleeve 101. A vacuum chuck 103 is arranged inside the mounting sleeve 101. The vacuum chuck 103 is connected to an air pump 104 through an air pipe. The mounting sleeve 101 is installed at one end of a rotating spline. The other end of the rotating spline is installed on a cross mounting bracket 61 through a mounting drive motor 106. The rotating spline is connected to the mounting drive motor through a belt. The mounting drive motor is installed on the cross mounting bracket 61. The spline shaft of the rotating spline is a hollow shaft. The hollow shaft is connected to a glue supply pump 107 and the air pump 104 through a multi-channel rotary joint. The mounting sleeve 101 and the air pipe are both connected to the multi-channel rotary joint. A plugging assembly is arranged at the bottom of the turntable 26. The plugging assembly includes a plugging motor 108. A plugging plate 109 is arranged on the output shaft of the plugging motor 108. The plugging motor 108, the glue supply pump 107, the air pump 104, the mounting drive motor 106 and the mounting drive motor are all electrically connected to the control mechanism 1.

[0065] The control mechanism 1 is used to control the combined visualization mechanism, the environment simulation mechanism and the operation mechanism, and collect and display the data of the environment simulation mechanism and the strain gauge in real time.

[0066] Based on the above method of an experimental device for measuring in-situ stress by the simulated in-situ stress relief method, the specific steps are as follows:

[0067] Step S1: Prepare a specimen, place the specimen on the turntable 26, and arrange strain gauges on the surface of the specimen according to the test requirements to form a strain measurement and acquisition mechanism on the specimen surface.

[0068] Step S2: Start the confining pressure unit to place the specimen in the test position, start the CT imaging device 2 to acquire the initial specimen image, and then start the scanning acoustic imaging device 3 to acquire the initial acoustic wave of the specimen.

[0069] Step S3: Start the rotary drive motor 62 to set the drilling test hole unit 7 opposite to the specimen, start the first lifting hydraulic cylinder 71 and the drilling machine 72 to drill a test hole with a diameter in the range of 20 - 50 mm at the center position of the specimen;

[0070] After drilling the test hole, start the rotary drive motor 62 to set the test hole cleaning unit 9 opposite to the specimen, start the vacuum cleaner 98, the heater 99 and the cleaning drive motor 911 in the test hole cleaning unit 9. Under the action of the ball spline 11, the rotating tube 91 rotates and descends into the test hole simultaneously to scrape pumice on the hole wall of the test hole, flush the hole wall and suck dust; at the same time, the hole diameter is detected by the distance detection sensor 910.

[0071] After cleaning the test hole, start the rotary drive motor 62 to set the strain gauge installation unit 10 opposite to the specimen. The installation drive motor 106 drives the installation sleeve 101 to descend to the bottom of the test hole. Start the plugging motor 108 to set the plugging plate 109 opposite to the test hole. Release the vacuum suction cup 103 by controlling the air pump 104 so that the strain gauge is placed on the plugging plate 109 under the action of gravity, ensuring that the strain gauge is installed at the central position of the test hole. Start the installation drive motor to drive the installation sleeve 101 to rotate, and at the same time start the glue supply pump 107 and the installation drive motor 106 so that the adhesive inside the installation sleeve 101 flows into the gap between the strain gauge and the test hole in a spiral manner; adjust the rotation speed of the installation drive motor and the lifting speed of the installation drive motor 106 according to the test hole diameter measured in Step S4.

[0072] After the adhesive is fully cured and the strain gauge is in close contact and firmly adhered to the hole wall of the test hole, start the CT imaging device 2 to acquire the pre - test specimen image, and then start the scanning acoustic imaging device 3 to acquire the pre - test acoustic wave of the specimen.

[0073] Step S7: Start the temperature regulation unit 5 to heat the specimen until the set test temperature is reached. After heating is completed, start the pressure - applying hydraulic cylinder 43 until the set confining pressure is reached.

[0074] Start the rotary drive motor 62 so that the stress relief unit 8 is disposed opposite to the specimen. Start the second lifting hydraulic cylinder 81 and the thin-wall sleeve hole drilling machine 82 to drill a relief hole concentric with the test hole. The diameter of the relief hole ranges from 110 to 160 mm, separating the core around the strain gauge from the specimen, thereby achieving stress relief. At the same time, the CT imaging device 2 is used to collect the specimen images in real time, and the data of the strain gauges and strain meters are collected in real time to achieve the collection of the data of the surface stress change and the internal stress change of the specimen. During the stress relief process, the specimen acoustic wave is collected regularly. The process of collecting the specimen acoustic wave is as follows:

[0075] Turn off the CT imaging device 2, the second lifting hydraulic cylinder 81 and the thin-wall sleeve hole drilling machine 82. The lifting mounting plate 46 rises so that the ultrasonic transducer 31 and the receiver 32 are disposed opposite to the specimen. Start the ultrasonic transducer 31 and the receiver 32 to collect the acoustic wave. After the collection is completed, the lifting mounting plate 46 descends, and the CT imaging device 2, the second lifting hydraulic cylinder 81 and the thin-wall sleeve hole drilling machine 82 are started to continue the stress relief until the stress relief is completed. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A test device for measuring ground stress by simulating on-site stress relief method, characterized in that: include, A combined visualization mechanism, used for collecting the whole internal image of the sample; the combined visualization mechanism includes a CT imaging device and a scanning acoustic imaging device; the scanning acoustic imaging device includes a plurality of ultrasonic transducers and a plurality of relatively arranged receivers, and the ultrasonic transducers and the receivers are both connected to the acoustic analyzer; an environmental simulation mechanism, the environmental simulation mechanism includes a confining pressure applying unit and a temperature regulating unit, used for simulating the confining pressure and temperature environment on site; the confining pressure applying unit includes an L-shaped fixing plate and two pressure applying plates, the L-shaped fixing plate and one of the pressure applying plates are both provided with through holes, a lifting mounting plate is arranged in the through hole, the two lifting mounting plates are respectively installed with the ultrasonic transducer and the receiver, a tightening member is arranged on one side of the lifting mounting plate, the tightening member includes a top ball, the top ball is connected to one end of the tightening spring, and the other end of the tightening spring is arranged in the blind hole of the lifting mounting plate; The operating mechanism is used for drilling test holes, stress relief, cleaning test holes and installing strain gauges; the operating mechanism includes a rotating bracket, on which a test hole drilling unit, a test hole cleaning unit, a strain gauge installation unit and a stress relief unit are respectively arranged; the test hole cleaning unit includes a rotating tube, on the outer side of the rotating tube, two telescopic scrapers are symmetrically arranged, the two telescopic scrapers are arranged in the groove on the outer side of the rotating tube through a spring, the two telescopic scrapers divide the rotating tube into a cleaning side and a detection side, the lower half of the cleaning side is provided with an air blowing port, the air blowing port is provided with a filter screen, the upper plate part of the cleaning side and the detection side are both provided with a dust suction port, and the dust suction port is connected to the cleaning side. The connecting pipe is connected to the dust suction pipe inside the rotating pipe, the rotating pipe and the dust suction pipe are connected to the vacuum cleaner through a multi-channel rotating joint, the rotating pipe is connected to the air outlet pipe of the vacuum cleaner, and the dust suction pipe is connected to the air inlet pipe of the vacuum cleaner; a heater is arranged on the air inlet pipe, and at least one row of distance detection sensors is arranged on the detection side; the rotating pipe is arranged at one end of the ball spline, the ball spline is connected to the cleaning drive motor through a belt, the cleaning drive motor is installed on the cross mounting frame, the cleaning drive motor is connected to the lifting gear rack assembly through a bevel gear set and a chain, and the gear and the bevel gear set in the lifting gear rack assembly are arranged on the cross mounting frame; The control mechanism is used to control the combined visualization mechanism, the environmental simulation mechanism and the operating mechanism, and to continuously collect data from the environmental simulation mechanism and the strain gauge in real time and display them.

2. The test device for measuring ground stress by simulating on-site stress relief method according to claim 1, characterized in that: The CT imaging device includes a bracket, on which two mounting side plates are arranged, on which a transmitter and a detector are connected via a lift, and a turntable is arranged in the middle of the bracket; The turntable, the transmitter, the detector and the sound wave analyzer are all electrically connected to the control mechanism.

3. The test device for measuring ground stress by simulating on-site stress relief method according to claim 2, characterized in that: The two pressure plates are connected to a pressure hydraulic cylinder, the two pressure plates and the L-shaped fixed plate form a frame structure, the two pressure plates are provided with pressure sensors, and the L-shaped fixed plate and the pressure hydraulic cylinder are fixed on the turntable; The lifting and lowering mounting plate, the pressure hydraulic cylinder and the pressure sensor are all electrically connected to the control mechanism.

4. The test device for measuring ground stress by simulating on-site stress relief method according to claim 3, characterized in that: The temperature regulating unit comprises a lower heating plate arranged on the turntable, and side heating plates and temperature detection optical fibers are arranged inside an L-shaped fixing plate and another pressure plate. The lower heating plate, the side heating plates and the temperature detection optical fibers are all electrically connected to the control mechanism.

5. The test device for measuring ground stress by simulating on-site stress relief method according to claim 4, characterized in that: The rotating bracket, the test hole drilling unit, the test hole cleaning unit, the strain gauge installation unit and the stress relief unit are all electrically connected to the control mechanism.

6. The test device for measuring ground stress by simulating on-site stress relief method according to claim 5, characterized in that: A cross mounting frame is arranged on the top of the rotating bracket. The test hole drilling unit, the test hole cleaning unit, the strain gauge mounting unit and the stress relief unit are respectively mounted on the four extension ends of the cross mounting frame. The cross mounting frame is connected to a rotating drive motor, which is mounted on the rotating bracket and electrically connected to the control mechanism.

7. The test device for measuring ground stress by simulating on-site stress relief method according to claim 6, characterized in that: The test hole drilling unit includes a first lifting hydraulic cylinder, and a drilling machine is provided at the telescopic end of the first lifting hydraulic cylinder; the stress relief unit includes a second lifting hydraulic cylinder, and a thin-walled casing drilling machine is provided at the telescopic end of the second lifting hydraulic cylinder; The first lifting hydraulic cylinder, the drilling machine, the second lifting hydraulic cylinder and the thin-wall casing drilling machine are all electrically connected to the control mechanism.

8. The test device for measuring ground stress by simulating on-site stress relief method according to claim 7, characterized in that: The cleaning drive motor, the dust collector, the distance detection sensor and the heater are all electrically connected to the control mechanism.

9. The test device for measuring ground stress by simulating on-site stress relief method according to claim 8, characterized in that: The strain gauge installation unit includes an installation sleeve, which is hollow and has a plurality of glue outlets at its open end. A vacuum suction cup is provided inside the installation sleeve, which is connected to an air pump through an air pipe. The installation sleeve is installed at one end of a rotating spline, and the other end of the rotating spline is installed on a cross mounting frame through a lifting cylinder. The rotating spline is connected to an installation drive motor through a belt, and the installation drive motor is installed on the cross mounting frame. The spline shaft of the rotating spline is a hollow shaft, which is connected to a glue supply pump and an air pump through a multi-channel rotating joint, and the installation sleeve and the air pipe are both connected to the multi-channel rotating joint. A plugging assembly is provided at the bottom of the turntable, and the plugging assembly includes a plugging motor, and a plugging plate is provided on the output shaft of the plugging motor. The plugging motor, the glue supply pump, the air pump, the lifting cylinder and the installation drive motor are all electrically connected to the control mechanism.

10. A method for testing a device for measuring ground stress by simulating on-site stress relief method according to claim 9, characterized in that: The specific steps are as follows: Step S1: Prepare a sample, place the sample on a turntable, and arrange strain gauges on the sample surface according to test requirements to form a sample surface strain measurement and collection mechanism; Step S2: starting the confining pressure unit so that the sample is in the test position, starting the CT imaging device to collect the initial sample image, and then starting the scanning acoustic wave imaging device to collect the initial acoustic wave of the sample; Step S3: Start the rotary drive motor so that the test hole drilling unit is arranged opposite to the sample, and start the first lifting hydraulic cylinder and the drilling machine to drill a test hole with a diameter ranging from 20 to 50 mm at the center of the sample; Step S4: After drilling the test hole, start the rotary drive motor so that the test hole cleaning unit is arranged opposite to the sample, start the vacuum cleaner, heater and cleaning drive motor in the test hole cleaning unit, and under the action of the ball spline, the rotary tube rotates and descends into the test hole at the same time, scrapes the pumice stone from the hole wall of the test hole, flushes the hole wall and removes the dust; at the same time, the aperture detection is performed through the distance detection sensor; Step S5: After the test hole is cleaned, the rotation drive motor is started so that the strain gauge installation unit is arranged relative to the sample, the lifting cylinder drives the installation sleeve to descend to the bottom of the test hole, the plugging motor is started so that the plugging plate is arranged relative to the test hole, and the vacuum suction cup is released by controlling the air pump so that the strain gauge is placed on the plugging plate under the action of gravity, the installation drive motor is started to drive the installation sleeve to rotate, and the glue supply pump and the lifting cylinder are started at the same time, so that the adhesive inside the installation sleeve flows into the gap between the strain gauge and the test hole in a spiral manner; according to the test aperture measured in step S4, the rotation speed of the installation drive motor and the lifting speed of the lifting cylinder are adjusted; Step S6: After the adhesive is cured and the strain gauge is bonded to the wall of the test hole, the CT imaging device is started to collect the sample image before the test, and then the scanning acoustic wave imaging device is started to collect the acoustic wave of the sample before the test; Step S7: starting the temperature regulating unit to heat the sample until the set test temperature is reached, and after the heating is completed, starting the pressure hydraulic cylinder until the set confining pressure is reached; Step S8: Start the rotary drive motor so that the stress relief unit is arranged relative to the sample, start the second lifting hydraulic cylinder and the thin-walled casing drilling machine to drill a relief hole concentric with the test hole, the aperture of the relief hole is in the range of 110-160mm, so that the core around the strain gauge is separated from the sample, thereby achieving stress relief. At the same time, the sample image is collected in real time by the CT imaging device, and the data of the strain gauge and the strain gauge are collected in real time to realize the collection of the stress change data on the surface of the sample and the stress change data inside the sample. The sample sound wave is collected regularly during the stress relief process. The process of collecting the sample sound wave is as follows: Turn off the CT imaging equipment, the second lifting hydraulic cylinder and the thin-walled casing drilling rig, raise the lifting mounting plate so that the ultrasonic transducer and the receiver are set relative to the sample, start the ultrasonic transducer and the receiver to collect sound waves, and after the collection is completed, lower the lifting mounting plate, start the CT imaging equipment, the second lifting hydraulic cylinder and the thin-walled casing drilling rig to continue stress relief until the stress relief is completed.

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