Rock folding shear failure test system and sound wave fundamental frequency characteristic test method

Abstract

The invention discloses a rock folding-shear failure test system and a sound wave fundamental frequency characteristic test method. The rock folding-shear failure test system comprises a rock folding-shear failure device and a sound wave detection device, the rock folding and shearing damage device comprises a computer, a strain gauge, a screw-in type pressurization device, a stress sensor, a displacement sensor, a spring support, a telescopic device support, a top pressing plate, a bottom plate and screws, the computer is in communication connection with the strain gauge, and the bottom of the screw-in type pressurization device and the bottom of the telescopic device support are fixed to the bottom plate. A top pressing plate is fixedly arranged on the top of the telescopic device support, a stress sensor and a displacement sensor are installed on the screw-in type pressurizing device and are in communication connection with a computer, and the bottom end of a spring support is fixed to a bottom plate through a screw. The device can realize real-time monitoring of sound waves when the rock is subjected to folding and shearing damage, is used for real-time monitoring of the sound waves when the rock is subjected to folding and shearing damage, and has the advantages of simple equipment structure, free disassembly of each part, convenience in operation and clear steps.

Description

Technical Field

[0001] The invention belongs to the technical field of earthquake prediction, and in particular relates to a rock shear failure test system and an acoustic wave fundamental frequency characteristic test method. Background Art

[0002] Earthquake prediction is a key research direction for geological researchers, and earthquake prediction is even more important for social progress and development. The elastic rebound theory holds that earthquakes occur because of fractures and dislocations in the rocks in the earth's crust. Rocks themselves are elastic, and rocks that have undergone elastic deformation when fractures occur will rebound as a whole in the opposite direction after the force disappears, returning to their original state. This rebound can produce amazing speed and force, releasing long-accumulated energy in an instant, causing earthquakes.

[0003] Earthquakes will generate geoacoustic precursor signals during their development, which are caused by the release of energy when some weak rock structure surfaces are destroyed during the development of an earthquake. When rocks are close to being destroyed under stress, the high-energy state of the stress concentration area is unstable, so they will inevitably transition to a stable low-energy state. During this transition, strain energy will be rapidly released in the form of elastic waves, causing the generation and expansion of microcracks, and generating sound waves or ultrasonic waves, which is the so-called rock acoustic emission phenomenon.

[0004] The generation mechanism of acoustic emission has certain similarities with earthquakes. Many characteristics of acoustic emission are similar to those of earthquakes, such as the magnitude-frequency relationship, waveform characteristics and propagation mode, etc. It is a "miniature version" of earthquakes. Studying acoustic emission in the rock deformation process is of great help to earthquake research. Acoustic emission technology is very promising for actual monitoring in laboratories and field observations. The use of acoustic emission technology to predict landslides in mining areas and rock collapse caused by mining also has a monitoring and forecasting function. The acoustic emission signal of the rock can be continuously and in real time monitored by the sound wave receiving instrument, and then the generation and expansion of cracks inside the rock can be analyzed in real time, and the location of the damage can be located. It has become an important means of monitoring and early warning of fracture and instability of brittle materials such as rocks and concrete, so the corresponding research has also become a hot topic in this field.

[0005] At present, the research on the acoustic wave signals generated during rock destruction is not in-depth enough, and the value of geoacoustic precursor signals in the process of earthquake development needs to be further explored. Summary of the invention

[0006] In view of the above-mentioned deficiencies in the prior art, a rock shear failure test system and an acoustic fundamental frequency characteristic test method provided by the present invention solve the problem of large errors in extracting acoustic wave signals generated during the rock failure process.

[0007] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a rock shear failure test system, including a rock shear failure device and an acoustic wave detection device connected to each other;

[0008] The rock shearing failure device includes a computer, a strain gauge, a screw-in pressurizing device, a stress sensor, a displacement sensor, a spring support, a retractable device bracket, a top pressure plate, a bottom plate and screws. The computer is connected to the strain gauge for communication. The bottom of the screw-in pressurizing device and the bottom of the retractable device bracket are fixed to the bottom plate. The top of the retractable device bracket is fixedly provided with a top pressure plate. The stress sensor and the displacement sensor are installed on the screw-in pressurizing device. The stress sensor and the displacement sensor are connected to the computer for communication. The bottom end of the spring support is fixed to the bottom plate by screws.

[0009] The acoustic wave detection device includes a sensor bracket, an acoustic wave sensor, a metal protective cover and a data transmission line. The bottom of the sensor bracket is fixed to the base plate, the metal protective cover is installed on the top of the cantilever rod of the sensor bracket, the acoustic wave sensor is installed inside the metal protective cover, and the acoustic wave sensor is connected to the strain gauge through the data transmission line.

[0010] Further: the spring support includes a support top plate, a support bottom plate, a spring, and a spring protection shell;

[0011] The support bottom plate is fixed to the bottom plate by screws, and the spring, spring protection shell and spring support top plate are placed on the spring support bottom plate in order from top to bottom.

[0012] Furthermore: the bottom plate is provided with a limiting hole, and the screw-in pressurizing device includes a handle, a screw column and a pressure plate arranged in sequence from top to bottom, wherein the upper end of the screw column is welded to the handle, and the lower end of the screw column is welded to the pressure plate.

[0013] The acoustic fundamental frequency characteristic test method is applied to the rock shear failure test system, including the following steps:

[0014] Sample preparation: Process the rock sample into a 50×50×150mm rectangular sample according to the experimental requirements;

[0015] Installation of the device and experimental preparation: Place the rectangular sample on the fixed spring support, adjust the top pressure plate to make the rectangular sample in close contact with the spring support, and adjust the sensor bracket to make the acoustic wave sensor face the middle of the rectangular sample;

[0016] Start the test: adjust the rectangular specimen and the acoustic wave sensor, and apply pressure by screwing in the pressure device until the rectangular specimen is destroyed. The computer collects data from the process of pressurizing the rectangular specimen until it is destroyed based on the stress sensor, displacement sensor, and acoustic wave sensor;

[0017] Data processing and analysis: The data from the process of pressurizing the rectangular sample until it is destroyed is analyzed to obtain the fundamental frequency characteristics of the sound waves generated by acoustic emission when the rock sample is destroyed. Combined with the displacement data and stress data, the characteristics of the sound wave changes of the rock sample during the experiment are obtained.

[0018] The beneficial effects of the present invention are:

[0019] (1) The present invention provides a rock shear failure test system and a method for testing the fundamental frequency characteristics of acoustic waves, which are used for indoor experimental research on the fundamental frequency characteristics of acoustic waves released by rock failure. The rock shear failure device simulates the stress and destruction process of rocks during earthquakes in the elastic rebound theory, and an acoustic wave detection device is used to collect in real time the acoustic wave data released by the energy release of rock samples during the test. By analyzing the fundamental frequency characteristics of acoustic wave information during the shear failure of rocks, in-depth research is conducted on the characteristics of acoustic wave changes generated by rocks during stress and destruction, and high-precision acoustic wave signals are extracted, which has a great reference significance for analyzing the physical characteristics of rock failure acoustic wave information and exploring the value of geoacoustic signals in earthquake prediction.

[0020] (2) The present invention can realize real-time monitoring of sound waves when rock undergoes shear failure, and is used for indoor research on real-time monitoring of sound waves of rock shear failure. It has the advantages of simple equipment structure, freely disassembled parts, easy operation, and clear steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a rock shear failure test system of the present invention;

[0022] Figure 2 It is a front view of the rock shear breaking device of the present invention;

[0023] Figure 3 It is a front view of the acoustic wave detection device of the present invention;

[0024] Figure 4 A front view of a spring support of the present invention;

[0025] Figure 5 It is a flow chart of the method for testing the fundamental frequency characteristics of sound waves of the present invention;

[0026] Among them: 1. Computer; 2. Strain gauge; 3. Rock shearing destruction device; 301. Screw-in pressurizing device; 302. Stress sensor; 303. Displacement sensor; 304. Spring support; 304-1. Support top plate; 304-2. Support bottom plate; 304-3. Spring; 304-4. Spring protective shell; 305. Retractable device bracket; 306. Top pressure plate; 307. Bottom plate; 308. Screw; 4. Acoustic wave detection device; 401. Sensor bracket; 402. Acoustic wave sensor; 403. Metal protective cover; 404. Data transmission line; 5. Rectangular specimen. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0028] Embodiment 1:

[0029] like Figures 1-2 As shown, in one embodiment of the present invention, a rock shear failure test system includes a rock shear failure device 3 and an acoustic wave detection device 4 connected to each other;

[0030] The rock shearing destruction device 3 includes a computer 1, a strain gauge 2, a screw-in pressurizing device 301, a stress sensor 302, a displacement sensor 303, a spring support 304, a retractable device bracket 305, a top pressure plate 306, a bottom plate 307 and a screw 308. The computer 1 is connected in communication with the strain gauge 2. The bottom of the screw-in pressurizing device 301 and the bottom of the retractable device bracket 305 are fixed on the bottom plate 307. The top of the retractable device bracket 305 is fixedly provided with a top pressure plate 306. The retractable device bracket 305 can be retracted and adjusted in height through a steel groove slideway. The stress sensor 302 and the displacement sensor 303 are installed on the screw-in pressurizing device 301. The stress sensor 302 and the displacement sensor 303 are connected in communication with the computer 1 for detecting the stress and strain of the rock sample during loading. The bottom end of the spring support 304 is fixed to the bottom plate 307 by a screw 308.

[0031] like Figure 3As shown, in this embodiment, the acoustic wave detection device 4 includes a sensor bracket 401, an acoustic wave sensor 402, a metal protective cover 403 and a data transmission line 404. The bottom of the sensor bracket 401 is fixed to the base plate 307, the metal protective cover 403 is installed on the top of the cantilever rod of the sensor bracket 401, and the acoustic wave sensor 402 is installed inside the metal protective cover 403. The acoustic wave sensor 402 is connected to the strain gauge 2 through the data transmission line 404 for transmitting real-time acoustic wave data during the test.

[0032] In this embodiment, the sensor bracket 401 is composed of three sections, namely a vertical rod, a horizontal rod and a cantilever rod. A steering head for adjusting the direction is provided at the connection between the three sections. The sensor bracket 401 is used to clamp the acoustic wave sensor 402 .

[0033] like Figure 4 As shown, in this embodiment, the spring support 304 includes a support top plate 304-1, a support bottom plate 304-2, a spring 304-3, and a spring protection shell 304-4;

[0034] The support base plate 304-2 is fixed to the base plate 307 by screws 308, and the spring 304-3, the spring protection shell 304-4, and the spring support top plate 304-1 are placed on the spring support base plate 304-2 in order from top to bottom.

[0035] The bottom plate 307 is provided with a limiting hole, and the screw-in pressurizing device 301 includes a handle, a screw column and a pressing plate arranged in sequence from top to bottom, wherein the upper end of the screw column is welded to the handle, and the lower end of the screw column is welded to the pressing plate.

[0036] The screw-in pressurizing device 301 is used for rotary pressurizing and can be used with an external sleeve rod. By adopting the screw-in pressurizing method, the displacement can be controlled and adjusted.

[0037] In this embodiment, the center of the bottom plate 307 is provided with spring support fixing areas on both sides along the length direction, and at the four corners of the support fixing area, there are spring support fixing areas 12×12 mm away from the edge of the area. Screws 308 are used to fix the support to the base plate 307.

[0038] like Figure 5 As shown, the acoustic fundamental frequency characteristic test method is applied to the rock shear failure test system, including the following steps:

[0039] Sample preparation: According to the experimental requirements, the rock sample is processed into a 50×50×150 mm rectangular sample 5;

[0040] Installation of the device and experimental preparation: Place the rectangular sample 5 on the fixed spring support 304, adjust the top pressure plate 306 to make the rectangular sample 5 and the spring support 304 in close contact, and adjust the sensor bracket 401 to make the acoustic wave sensor 402 face the middle of the rectangular sample 5;

[0041] Start the test: adjust the rectangular parallelepiped sample 5 and the acoustic wave sensor 402, and apply pressure by screwing in the pressure-applying device until the rectangular parallelepiped sample 5 is destroyed, and collect data during the process of pressurizing the rectangular parallelepiped sample 5 until destruction through the computer 1 according to the stress sensor 302, the displacement sensor 303 and the acoustic wave sensor 402;

[0042] Data processing and analysis: The data from the process of pressurizing the rectangular sample 5 until it was destroyed were analyzed to obtain the fundamental frequency characteristics of the sound waves generated by acoustic emission when the rock sample was destroyed. Combined with the displacement data and stress data, the characteristics of the sound wave changes of the rock sample during the experiment were obtained.

[0043] Embodiment 2:

[0044] This embodiment provides a specific experimental case for Embodiment 1:

[0045] A rock shear failure test device and a method for testing the fundamental frequency characteristics of sound waves thereof, comprising a rock shear failure device 3 and a sound wave detection device 4; the rock shear failure device 3 comprises a rock creep instrument and a shear failure test device; the rock creep instrument is composed of a host, an oil source system, an electric control device, computer software, etc., and the shear failure test device is composed of a base, a bracket and a replaceable spring. The sound wave detection device 4 adopts a PM461 audio microphone kit.

[0046] A rock shear failure test device and a method for testing the fundamental frequency characteristics of sound waves thereof, comprising the following steps:

[0047] (1) Sample preparation: According to the experimental requirements, the rock sample is processed into a 50×50×150 mm rectangular sample 5;

[0048] (2) Debugging of rock creep instrument: Before the test, the operating status of the creep instrument needs to be checked and debugged, mainly to check whether the system pressure is stable within the specified range, whether there is any abnormal sound during operation, whether the connection between the electronic control device and the computer is normal, etc., to ensure that the creep instrument can operate normally during the experiment.

[0049] (3) Install the rock shear failure test device: Install the loading support. First, place a steel plate gasket on the loading platform of the creep instrument to keep it flush with the lower pressure plate of the creep instrument main shaft. Then place the bottom plate of the rock shear failure device flat on the loading platform of the rock creep instrument to ensure that there is no gap between the bottom plate and the gasket and the loading platform. Align the sample loading end with the creep instrument main shaft. The upper part of the sample clamping end should extend out of the creep instrument main shaft and remain able to move upward freely without contacting the creep instrument loading main shaft. After the loading device is placed stably and adjusted in position, the base spring is installed. After the shear failure test device is installed, place the prepared rock sample on the loading support to ensure that one end can be tightly clamped with the clamping end spring support 304 without too much gap. At the same time, adjust the position of the loading end support again, place a steel plate gasket with a size of 50mm×50mm×5mm above the loading end, and align it with the rock creep instrument.

[0050] (4) Installing the microphone: Clamp the microphone stand next to the loading device, and align the microphone with the rock sample placement position by adjusting the telescopic stand. Install the microphone protective cover, connect the data cable to computer 1, and start the recording software to debug whether the microphone is working properly.

[0051] (5) Collecting environmental noise: Use Adobe Audition 2020 audio software to record the sound wave signal collected by the microphone during the test. After all the test equipment is installed, turn on the test equipment, but do not perform the loading test. Open the computer recording software and use the microphone to collect and record the environmental noise generated during the operation of the test equipment. Use it as the base noise to prepare for the subsequent noise reduction process.

[0052] (6) Start the test: After the device is installed and the circuit is checked to be normal, adjust the sample and the pickup, and apply pressure through the rock creep tester until the rock sample is destroyed;

[0053] (7) Data processing and analysis: After the experiment, the data tested by the creep instrument and the acoustic wave monitoring device are analyzed to study the fundamental frequency characteristics of the acoustic waves generated by acoustic emission when the rock sample is destroyed. Combined with the displacement and stress data, the characteristics of the acoustic wave changes of the rock sample during the entire experimental process are analyzed.

[0054] The beneficial effects of the present invention are as follows: the present invention provides a rock shear failure test system and a sound wave fundamental frequency characteristic test method, which are used for indoor experimental research on the fundamental frequency characteristics of sound waves released by rock failure. The rock shear failure device 3 simulates the stress and destruction process of rocks in the earthquake process in the elastic rebound theory, and the sound wave detection device 4 is used to collect the sound wave data released by the energy release of the rock sample during the test in real time. By analyzing the fundamental frequency characteristics of the sound wave information of the rock during the shear failure process, in-depth research is conducted on the characteristics of the sound wave changes generated by the rock during the stress failure process, and high-precision sound wave signals are extracted, which has a great reference significance for analyzing the physical characteristics of the rock failure sound wave information and exploring the value of the geoacoustic signal in earthquake prediction.

[0055] The present invention can realize real-time monitoring of sound waves when rock undergoes shear fracture and is used for indoor research on real-time monitoring of sound waves of rock shear fracture and has the advantages of simple equipment structure, freely disassembled parts, convenient operation and clear steps.

[0056] In the description of the present invention, it is necessary to understand that the orientation or positional relationship indicated by the terms "center", "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "radial", etc. is based on the orientation or positional relationship shown in the drawings, and 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 cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", and "third" are used only for descriptive purposes, and cannot be understood as indicating or implying the relative importance or the number of implicitly specified technical features. Therefore, the features defined by "first", "second", and "third" may explicitly or implicitly include one or more of the features.

Claims

1. A rock shear failure test system, characterized in that: It comprises a rock shearing destruction device (3) and an acoustic wave detection device (4) which are connected to each other; The rock shearing destruction device (3) comprises a computer (1), a strain gauge (2), a screw-in pressurizing device (301), a stress sensor (302), a displacement sensor (303), a spring support (304), a retractable device bracket (305), a top pressure plate (306), a bottom plate (307) and a screw (308); the computer (1) is connected to the strain gauge (2) in communication; the bottom of the screw-in pressurizing device (301) and the bottom of the retractable device bracket (305) are fixed to the bottom plate (307); the top of the retractable device bracket (305) is fixedly provided with a top pressure plate (306); the stress sensor (302) and the displacement sensor (303) are installed on the screw-in pressurizing device (301); the stress sensor (302) and the displacement sensor (303) are connected to the computer (1) in communication; and the bottom end of the spring support (304) is fixed to the bottom plate (307) by a screw (308); The acoustic wave detection device (4) comprises a sensor bracket (401), an acoustic wave sensor (402), a metal protective cover (403) and a data transmission line (404); the bottom of the sensor bracket (401) is fixed to a bottom plate (307); the metal protective cover (403) is mounted on the top of a cantilever rod of the sensor bracket (401); the acoustic wave sensor (402) is mounted inside the metal protective cover (403); and the acoustic wave sensor (402) is connected to a strain gauge (2) for communication via the data transmission line (404).

2. The rock shear failure test system according to claim 1 is characterized in that: The spring support (304) comprises a support top plate (304-1), a support bottom plate (304-2), a spring (304-3), and a spring protection shell (304-4); The support base plate (304-2) is fixed to the base plate (307) by means of screws (308), and the spring (304-3), the spring protection shell (304-4), and the spring support top plate (304-1) are placed on the spring support base plate (304-2) in order from top to bottom.

3. The rock shear failure test system according to claim 1, characterized in that: The bottom plate (307) is provided with a limiting hole, and the screw-in pressurizing device (301) comprises a handle, a screw column and a pressing plate arranged in sequence from top to bottom, wherein the upper end of the screw column is welded to the handle, and the lower end of the screw column is welded to the pressing plate.

4. The acoustic wave fundamental frequency characteristic testing method according to any one of claims 1 to 3 is applied to a rock shear failure test system, characterized in that: The following steps are involved: Sample preparation: Process the rock sample into a 50×50×150 mm rectangular sample according to the experimental requirements (5); Installation of the device and experimental preparation: Place the rectangular sample (5) on the fixed spring support (304), adjust the top pressure plate (306) to make the rectangular sample (5) and the spring support (304) in close contact, and adjust the sensor bracket (401) to make the acoustic wave sensor (402) face the middle of the rectangular sample (5); Start the test: adjust the rectangular parallelepiped sample (5) and the acoustic wave sensor (402), apply pressure by screwing in the pressure-applying device until the rectangular parallelepiped sample (5) is destroyed, and collect data during the process of pressurizing the rectangular parallelepiped sample (5) until destruction through the computer (1) according to the stress sensor (302), the displacement sensor (303) and the acoustic wave sensor (402); Data processing and analysis: The data from the process of pressurizing the rectangular parallelepiped sample (5) until it is destroyed is analyzed to obtain the fundamental frequency characteristics of the sound waves generated by acoustic emission when the rock sample is destroyed. Combined with the displacement data and stress data, the characteristics of the sound wave changes of the rock sample during the experiment are obtained.

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