Temperature-controllable rock shear creep experiment device and method and instability failure prediction method

Abstract

The invention provides a temperature-controllable rock shear creep experiment device and method and an instability failure prediction method. The temperature-controllable rock shearing creep experimental device comprises a shearing unit, a temperature control unit, a normal loading unit, a horizontal loading unit, a displacement sensor, an acoustic emission sensor and an infrasonic wave sensor. The temperature-controllable rock shear creep experimental device disclosed by the invention is simple in structure and convenient to operate; the device can be used for simulating rock shear creep experiments in different temperature environments; according to the device, the acoustic emission acquisition system and the infrasonic wave acquisition system are introduced at the same time, acoustic emission signals and infrasonic wave signals released by the sample in the shear creep process can be monitored in real time, and the shear creep instability failure process of the rock sample is predicted through the acoustic emission signals and / or the infrasonic wave signals. And the method has important significance for deeply researching the shear creep characteristics of the rock.

Description

Technical Field

[0001] The invention relates to the technical field of rock mass engineering, and in particular to a temperature-controllable rock shear creep experimental device, method and instability failure prediction method. Background Art

[0002] Temperature has a very important influence on the physical and mechanical properties of rocks. In actual engineering, it is of great practical significance to understand the influence of temperature on the physical and mechanical properties of rocks and take corresponding measures to accurately evaluate the mechanical properties of rocks. Therefore, through appropriate experimental devices, methods and instability and failure prediction methods, we can better understand the mechanical properties of rocks under different temperature conditions and provide a reliable basis for rock engineering.

[0003] Rock creep refers to the phenomenon that rocks continue to slowly deform under long-term loads. The rock creep characteristics have an important impact on the stability and safety of rock engineering. Since the rock mass is a discontinuous, heterogeneous and anisotropic geological body composed of various types of rocks containing weak structural surfaces, shear creep failure is one of its main forms of failure under long-term loads. Therefore, the influence of rock shear creep needs to be considered during the design and construction process to ensure the long-term stability of rock engineering.

[0004] At present, the existing shear creep test devices or equipment can basically meet the needs of rock shear creep test, but the test devices are relatively large and complex, and it is difficult to achieve real-time control of rock temperature during the shear creep test. Therefore, it is necessary to invent a rock shear creep test device, method and instability failure prediction method with real-time temperature control. Summary of the invention

[0005] In view of the shortcomings of the current shear creep experimental device, the present invention provides a temperature-controllable rock shear creep experimental device, method and instability failure prediction method.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a temperature-controllable rock shear creep experimental device, comprising:

[0008] A shearing unit comprising:

[0009] An experimental box, wherein a first shear box and a second shear box are disposed in the experimental box, and the first shear box and the second shear box are used to place the rock to be tested;

[0010] The first shear box is connected to first cooling / heating pipes on both sides respectively;

[0011] The two sides of the second shear box are respectively connected with second cold / hot pipes;

[0012] A temperature control unit, comprising a temperature control box, wherein a temperature-controllable energy storage medium is arranged in the temperature control box;

[0013] The end of the first cooling / heating pipe away from the first shear box passes through the experimental box and is connected to the temperature control box;

[0014] The end of the second cooling / heating pipe away from the second shear box passes through the experimental box and is connected to the temperature control box;

[0015] a normal loading unit, which is used to apply a normal force to the first shear box;

[0016] a horizontal loading unit, which is used to apply a shear force to the second shear box;

[0017] A displacement sensor, used for monitoring the horizontal displacement of the first shear box;

[0018] A sound wave unit comprising:

[0019] An acoustic emission sensor, located on the second shear box and used for monitoring the acoustic emission signal during rock shear creep;

[0020] An infrasound sensor is used to monitor the infrasound signal during rock shear creep;

[0021] An acoustic emission collector, which is communicatively connected to the acoustic emission sensor to collect acoustic emission signals;

[0022] An infrasound wave collector, which is communicatively connected with the infrasound wave sensor to collect infrasound wave signals;

[0023] The calculation unit is respectively connected to the acoustic emission collector and the infrasound wave collector for communication, and calculates the acoustic emission signal and the infrasound wave signal.

[0024] Preferably, the normal loading unit comprises:

[0025] A T-shaped pressure block, comprising a vertical pressure block arranged vertically and a horizontal pressure block arranged horizontally, wherein the lower end of the vertical pressure block is connected to the first shear box, and the upper end of the vertical pressure block passes through the test box and is connected to the horizontal pressure block;

[0026] The normal counterweight block is located on the horizontal pressure block.

[0027] Preferably, the horizontal loading unit comprises:

[0028] A fixed pulley, which is located outside the experimental box;

[0029] A steel wire, one end of which is fixed to one side of the first shear box, and the other end of which is passed around a fixed pulley and connected to a horizontal counterweight;

[0030] The horizontal counterweight block is used to drive the first shear box to move in the horizontal direction.

[0031] Preferably, first temperature sensors are respectively provided on both sides of the first shear box, and the first temperature sensors are used to monitor the temperature inside the first shear box;

[0032] Second temperature sensors are respectively provided on both sides of the second shear box, and the second temperature sensors are used to monitor the temperature inside the second shear box.

[0033] Preferably, the experimental box includes a box body and a box door, and the box door is rotatably connected to the box body to open or close the box body.

[0034] Preferably, a limiting block is provided in the experimental box, a limiting groove is provided on the limiting block, and the second shear box is arranged in the limiting groove.

[0035] In a second aspect, the present invention further provides a temperature-controllable rock shear creep test method, comprising the following steps:

[0036] Providing the temperature-controllable rock shear creep experimental device;

[0037] The rock to be tested is placed between the first shear box and the second shear box, and the acoustic emission sensor is closely attached to the rock surface;

[0038] Using a temperature control box to control the energy storage medium to reach a set temperature, so that the first shear box and the second shear box are at the set temperature;

[0039] applying a normal force to the first shear box;

[0040] Apply shear force to the second shear box step by step. After applying each level of shear force, keep the shear force constant and observe and record the shear creep deformation of the rock. After the shear creep deformation is stable, apply the next level of shear force until the rock is sheared and destroyed, and then stop the experiment.

[0041] Calculate the rock shear strain. The shear strain calculation formula is: Where: γ is the shear strain, Δx is the shear creep deformation, and L is the length of the rock.

[0042] Preferably, the normal loading unit comprises a T-shaped pressure block and a normal counterweight block;

[0043] A normal force is applied to the first shear box using a normal counterweight, wherein the mass of the normal counterweight is calculated according to the following formula:

[0044] Where: m1 is the required normal counterweight mass, σ is the uniaxial compressive strength of rock obtained through uniaxial compression test, A is the area of ​​the lower end surface of the first shear box, g is the gravitational acceleration, b is the percentage of the required uniaxial compressive strength, and the value range of b is 10-60%;

[0045] The horizontal loading unit comprises: a fixed pulley, a steel wire and a horizontal counterweight block, and the horizontal counterweight block is used to apply shear force to the second shear box step by step;

[0046] Among them, the mass of the first-level horizontal counterweight is: Where: m2 is the mass of the first-stage horizontal counterweight required, τ is the shear strength of the rock obtained through the direct shear test, A is the area of ​​the lower end surface of the first shear box, c1 is the percentage of the shear strength occupied by the first-stage shear creep test, the value range of c1 is 30-95%, and g is the acceleration of gravity;

[0047] The mass of the horizontal counterweight required for level i is: Where: m i is the mass of the i-th level counterweight block to be applied, i=2, 3...n;

[0048] m i-1 is the mass of the horizontal counterweight applied to the i-1th level;

[0049] c i is the percentage of shear strength accounted for by the i-th level shear creep test;

[0050] c i >c i-1 ;

[0051] c i The value range of is 30~95%;

[0052] τ is the shear strength of rock obtained through direct shear test, A is the area of ​​the lower end surface of the first shear box, and g is the gravitational acceleration;

[0053] The rock is saturated with water, has different water contents or is dry.

[0054] In a third aspect, the present invention also provides a temperature-controllable rock shear creep instability failure prediction method, comprising the following steps:

[0055] The rock shear creep experiment was carried out according to the method described;

[0056] Among them, during the rock shear creep process, an acoustic emission collector is used to collect the acoustic emission signals released during the rock shear creep process;

[0057] The infrasound wave acquisition instrument is used to collect the infrasound wave signal in the process of rock shear creep;

[0058] The instability and failure of rocks are predicted by using acoustic emission signals and / or infrasound signals.

[0059] Preferably, predicting the instability and failure of rock using acoustic emission signals and / or infrasound signals specifically includes:

[0060] The acoustic emission signal is processed to obtain the acoustic emission event rate, acoustic emission ringing count, acoustic emission energy, and acoustic emission main frequency;

[0061] The infrasound wave signal is processed to obtain the infrasound wave energy rate and the infrasound wave sub-dominant frequency respectively;

[0062] Among them, when a sudden increase signal appears in the acoustic emission event rate within a unit time, and / or a surge signal appears in the acoustic emission ring count within a unit time, and / or a sudden surge phenomenon appears in the acoustic emission energy within a unit time, and / or a sudden surge phenomenon appears in the infrasonic wave energy rate within a unit time, and / or an accumulation phenomenon appears in the main frequency of the acoustic emission in the frequency band of 200 to 250 kHz, and / or an accumulation phenomenon appears in the sub-main frequency of the infrasonic wave in the frequency band of 5 to 7 Hz, it is predicted that the rock will become unstable and fail.

[0063] The temperature-controllable rock shear creep experimental device, method and instability failure prediction method of the present invention have the following technical effects compared with the prior art:

[0064] 1. The temperature-controllable rock shear creep experimental device of the present invention has a simple structure and convenient operation, and can meet the needs of simulating rock shear creep experiments under different temperature environments in the laboratory;

[0065] 2. The temperature-controllable rock shear creep experimental device of the present invention simultaneously introduces an acoustic emission sensor and an infrasound sensor, which can monitor the acoustic emission signal and infrasound signal released by the sample during the shear creep process in real time, and use the acoustic emission signal and / or infrasound signal to predict the shear creep failure process of the rock sample, which is of great significance for in-depth research on the deformation characteristics and behavior laws of rocks; the temperature-controllable rock shear creep experimental device of the present invention can not only simulate rock shear creep experiments under different temperature environments, but also perform shear creep experiments on rocks in different states (saturated with water, with different water contents or dry), and at the same time, it can predict whether instability failure occurs during rock shear creep;

[0066] 3. The temperature-controllable rock shear creep experimental device of the present invention has a simple structure and is easy to operate, and provides an implementation scheme for conducting shear creep experiments under different temperature environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0068] Figure 1 It is a schematic structural diagram of the first shear box and the second shear box of the present invention;

[0069] Figure 2 It is a structural schematic diagram of the experimental box of the present invention;

[0070] Figure 3 It is a structural schematic diagram of the first shear box and the second shear box being placed in the experimental box;

[0071] Figure 4 It is a structural schematic diagram of the temperature-controllable rock shear creep experimental device of the present invention;

[0072] Figure 5 It is the characteristic diagram of acoustic emission event rate distribution;

[0073] Figure 6 It is the characteristic diagram of the distribution of acoustic emission ringing counts;

[0074] Figure 7 It is the characteristic diagram of acoustic emission energy distribution;

[0075] Figure 8 It is the characteristic diagram of the main frequency distribution of acoustic emission;

[0076] Fig. 9 It is the characteristic diagram of infrasound energy rate distribution;

[0077] Fig.10 It is the characteristic diagram of sub-dominant frequency distribution of infrasound wave;

[0078] Fig.11 This is a joint analysis diagram of acoustic emission signals and infrasound signals. DETAILED DESCRIPTION

[0079] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0080] In the description of the present invention, it should be understood that the directions or positions indicated by “upper” and the like are based on the directions or positions shown in the accompanying drawings, or are the directions or positions in which the product of the invention is usually placed when in use, or are directions or positions commonly understood by those skilled in the art. These directions or positions are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0081] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0082] The temperature-controllable rock shear creep experimental device of the present invention is as follows: Figures 1 to 4 As shown, including:

[0083] A shearing unit 1, comprising:

[0084] An experimental box 11, in which a first shear box 12 and a second shear box 13 are arranged on the upper and lower sides, and the rocks to be tested are placed between the first shear box 12 and the second shear box 13;

[0085] Both sides of the first shear box 12 are connected to first cooling / heating pipes 14;

[0086] The second shear box 13 is connected to the second cold / hot pipes 15 on both sides;

[0087] The temperature control unit comprises a temperature control box 2, in which a temperature-controllable energy storage medium is arranged;

[0088] The end of the first cooling / heating pipe 14 away from the first shear box 12 passes through the experimental box 1 and is connected to the temperature control box 2;

[0089] The end of the second cooling / heating pipe 15 away from the second shear box 13 passes through the experimental box 1 and is connected to the temperature control box 2;

[0090] A normal loading unit, which is used to apply a normal force to the first shear box 12;

[0091] A horizontal loading unit, which is used to apply a shear force to the second shear box 13;

[0092] A displacement sensor 4, which is used to monitor the horizontal displacement of the first shear box 12;

[0093] A sound wave unit comprising:

[0094] An acoustic emission sensor 31, which is located on the second shear box 13 and is used to monitor the acoustic emission signal during rock shear creep;

[0095] An infrasound sensor is used to monitor the infrasound signal during rock shear creep;

[0096] An acoustic emission collector 32, which is communicatively connected to the acoustic emission sensor 31 to collect acoustic emission signals;

[0097] An infrasound wave collector is communicatively connected with the infrasound wave sensor to collect infrasound wave signals;

[0098] The calculation unit 33 is respectively connected to the acoustic emission collector and the infrasound wave collector for communication, and calculates the acoustic emission signal and the infrasound wave signal.

[0099] The temperature-controllable rock shear creep experimental device of the present invention comprises: a shear unit 1, a temperature control unit, a normal loading unit, a horizontal loading unit, a displacement sensor 4, and an acoustic wave unit 3. The acoustic wave unit 3 comprises an acoustic emission sensor 31, an acoustic emission collector 32, an infrasound sensor, and a calculation unit 33. The shear unit 1 comprises: an experimental box 11, a first shear box 12, and a second shear box 13. The first shear box 12 and the second shear box 13 are arranged up and down in the experimental box 11. The first shear box 12 and the second shear box 13 are used to place the rock to be tested, that is, the upper and lower end surfaces of the rock to be tested are attached between the lower end surface of the first shear box 12 and the upper end surface of the second shear box 13; the first shear box 12 is connected to the first cold / heat pipe 14 on both sides; the second shear box 13 is connected to the second cold / heat pipe 15 on both sides. The first cold / heat pipe 14 and the second cold / heat pipe 15 are connected to the temperature control box 2. The control box 2 is provided with a temperature-controllable energy storage medium, that is, the temperature control box 2 can control the temperature of the energy storage medium, for example, the temperature of the energy storage medium can be controlled according to the experimental temperature. When the temperature of the energy storage medium is very low, such as -10°C, the first cooling / heat pipe 14 and the second cooling / heat pipe 15 are cooling pipes. When the temperature of the energy storage medium is very high, such as 60°C, the first cooling / heat pipe 14 and the second cooling / heat pipe 15 are heating pipes. After the energy storage medium enters the first cooling / heat pipe 14, it enters the first shear box 12, and flows out from the first cooling / heat pipe 14 on the other side and returns to the temperature control box 2, and circulates in this way so that the temperature of the first shear box 12 reaches the preset temperature. After the energy storage medium enters the second cooling / heat pipe 15, it enters the second shear box 13, and flows out from the second cooling / heat pipe 15 on the other side and returns to the temperature control box 2, and circulates in this way so that the temperature of the second shear box 13 reaches the preset temperature. A normal force (normal force is a force in the vertical direction) is applied to the first shear box 12 by a normal loading unit, and a shear force (shear force is a force in the horizontal direction) is applied to the second shear box 13 by a horizontal loading unit. The displacement sensor 4 is used to monitor the horizontal displacement of the first shear box 12 during the shear creep experiment; the acoustic emission sensor 31 is used to monitor the acoustic emission signal during rock shear creep, the acoustic emission collector 32 is used to collect the acoustic emission signal, and the calculation unit 33 is used to calculate the acoustic emission signal; the infrasound sensor (not shown) is used to monitor the infrasound signal during rock shear creep, the infrasound collector (not shown) is used to collect the infrasound signal, and the calculation unit is used to calculate the infrasound signal.

[0100] Specifically, the energy storage medium is a conventional energy storage medium such as water. The temperature control box 2 can be used to control the temperature of the energy storage medium in real time, thereby controlling the shear creep experiment to be performed within a predetermined range.

[0101] By using the temperature-controllable rock shear creep experimental device of the present invention, the shear creep process of the rock can be monitored under different temperature environments; the temperature-controllable rock shear creep experimental device of the present invention simultaneously introduces an acoustic emission sensor and an infrasound sensor, which can monitor the acoustic emission signal and the infrasound signal released by the sample during the shear creep process in real time, and use the acoustic emission signal and / or the infrasound signal to predict the shear creep failure process of the rock sample, which is of great significance for in-depth research on the deformation characteristics and behavior laws of the rock; the temperature-controllable rock shear creep experimental device and the experimental method of the present invention provide an implementation plan for conducting shear creep experiments under different temperature environments.

[0102] Specifically, the infrasonic wave sensor of the present invention does not need to be attached to or in contact with any component of the experimental device.

[0103] In some embodiments, the normal loading unit comprises:

[0104] T-shaped pressure block 5, which includes a vertical pressure block arranged vertically and a horizontal pressure block arranged horizontally, the lower end of the vertical pressure block is connected to the first shear box, and the upper end passes through the experimental box and is connected to the horizontal pressure block;

[0105] The normal counterweight block 51 is located on the horizontal pressure block.

[0106] Specifically, the normal loading unit includes a T-shaped pressure block 5 and a normal counterweight block 51. The T-shaped pressure block 5 includes a vertical pressure block and a horizontal pressure block that are perpendicular to each other. The normal counterweight block 51 is located on the horizontal pressure block. Normal counterweight blocks 51 of different masses are used to apply normal forces of different magnitudes to the first shear box 12.

[0107] In some embodiments, the horizontal loading unit comprises:

[0108] A fixed pulley 6, which is located outside the experimental box 11;

[0109] A steel wire 61, one end of which is fixed to one side of the first shear box 12, and the other end of which passes over the fixed pulley 6 and is connected to a horizontal counterweight 62;

[0110] The horizontal counterweight block 62 is used to drive the first shear box 12 to move in the horizontal direction.

[0111] In the above embodiment, the horizontal loading unit includes: a fixed pulley 6, a steel wire 61, and a horizontal counterweight 62. The steel wire 61 passes around the fixed pulley 6, and horizontal counterweights 62 of different masses are applied to the lower end of the steel wire 61, thereby applying shear forces of different magnitudes to the first shear box 12.

[0112] In some embodiments, first temperature sensors 16 are respectively disposed on both sides of the first shear box 12 , and the first temperature sensors 16 are used to monitor the temperature inside the first shear box 12 .

[0113] In some embodiments, second temperature sensors 17 are respectively disposed on both sides of the second shear box 13 , and the second temperature sensors 17 are used to monitor the temperature inside the second shear box 13 .

[0114] In some embodiments, the experimental box 11 includes a box body and a box door 10 , and the box door 10 can be rotatably connected to the box body to open or close the box body.

[0115] In some embodiments, a limiting block 18 is provided in the experimental box 11 , a limiting groove is provided on the limiting block 18 , and the second shear box 13 is disposed in the limiting groove.

[0116] In some embodiments, first cold / heat pipe holes are respectively provided on both sides of the first shear box 12, and the first cold / heat pipe 14 is connected to the first shear box 12 after passing through the first cold / heat pipe hole; second cold / heat pipe holes are respectively provided on both sides of the second shear box 13, and the second cold / heat pipe 15 is connected to the second shear box 13 after passing through the second cold / heat pipe hole.

[0117] In some embodiments, the experimental box 11 is placed on the first bracket 7 , the fixed pulley 6 is located on the fixed pulley bracket 63 , the acoustic emission collector 32 and the computing unit 33 are located on the second bracket 8 , and the computing unit 33 is also connected to the power module 34 .

[0118] In some embodiments, the first temperature sensor 16 and the second temperature sensor 17 are both platinum resistance thermometers.

[0119] In some embodiments, the dimensions of the first shear box 12 and the second shear box 13 are both 100mm×100mm×50mm in length×width×height, and the temperature control panel of the temperature box is installed on the outside of the temperature control box. The control panel is provided with a temperature display, a temperature adjustment switch, and a cooling / heating control switch.

[0120] Based on the same inventive concept, the present invention also provides a temperature-controllable rock shear creep test method, comprising the following steps:

[0121] S1. Provide the above-mentioned temperature-controllable rock shear creep experimental device;

[0122] S2, placing the rock to be tested between the first shear box and the second shear box, and making the acoustic emission sensor fit closely to the rock surface;

[0123] S3, using a temperature control box to control the energy storage medium to reach a set temperature, so that the first shear box and the second shear box are at the set temperature;

[0124] S4, applying a normal force to the first shear box;

[0125] S5, applying shear force to the second shear box step by step, maintaining the shear force constant after applying each level of shear force and observing and recording the shear creep deformation of the rock, and applying the next level of shear force after the shear creep deformation is stable;

[0126] S6. Calculate the rock shear strain. The shear strain calculation formula is: Where: γ is the shear strain, Δx is the shear creep deformation, and L is the length of the rock.

[0127] In some embodiments, the normal loading unit includes a T-shaped pressure block and a normal counterweight block;

[0128] A normal force is applied to the first shear box using a normal counterweight, wherein the mass of the normal counterweight is calculated according to the following formula:

[0129] Where: m1 is the required normal counterweight mass (in kg), σ is the uniaxial compressive strength of rock obtained through uniaxial compression test (in MPa), A is the area of ​​the lower end surface of the first shear box (in m 2 ), g is the acceleration due to gravity (unit is ), b is the percentage of uniaxial compressive strength required to be applied (in %).

[0130] Specifically, in the above embodiment, the value range of b is 10% to 60%, for example, the value range of b can be 10%, 20%, 30%, 40%, 50%, and 60%.

[0131] In some embodiments, the horizontal loading unit includes: a fixed pulley, a steel wire, and a horizontal counterweight block, and the horizontal counterweight block is used to apply shear force to the second shear box step by step;

[0132] Among them, the mass of the first-level horizontal counterweight is: Where: m2 is the mass of the first-stage horizontal counterweight required (in kg), τ is the shear strength of the rock obtained through the direct shear test (in MPa), A is the area of ​​the lower end surface of the first shear box (in m 2 ), c1 is the percentage of shear strength in the first-stage shear creep test (in %), g is the acceleration due to gravity (in );

[0133] The mass of the horizontal counterweight required for level i is: Where: m i is the mass of the i-th level counterweight block to be applied, i=2, 3...n;

[0134] m i-1 is the mass of the horizontal ballast block applied to the i-1th level (in kg);

[0135] ci is the percentage of shear strength accounted for by the i-th level shear creep test (in %);

[0136] τ is the shear strength of rock obtained through direct shear test (in MPa), A is the area of ​​the lower end surface of the first shear box (in m 2 ), g is the acceleration due to gravity (unit is ).

[0137] In the above embodiment, the value range of c1 is 30-95%, c i The value range of c is 30% to 95%, for example, 30%, 45%, 60%, 75%, 90%, 95%; and c i >c i-1 , that is, the shear force of the next level is greater than the shear force of the previous level. When shear creep is graded, c i The stress levels can be 15%, 30%, 45%, 60%, 75%, 90%, and 95% in sequence. After the deformation enters steady-state creep at this stress level, the next stress level is applied until the specimen is sheared and the experiment is stopped.

[0138] In some embodiments, before the shear creep experiment is performed, a uniaxial compression test and a direct shear test are first performed in an indoor laboratory to obtain the uniaxial compressive strength and shear strength of the sample, respectively. Both the uniaxial compression test and the direct shear test are performed on the RMT-150C rock mechanics experimental system, which is developed by the Wuhan Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, and has the advantages of high automation, simple operation, and easy control.

[0139] The uniaxial compression test process is as follows:

[0140] 1) Turn on the power and water valve and start the computer simultaneously;

[0141] 2) Turn on the operating system and start the low-pressure button to preheat the experimental system in a low-pressure state for 10 minutes;

[0142] 3) After preheating, press the high-voltage button to switch the experimental system to high-voltage state;

[0143] 4) Select a suitable load-bearing base and install it on the base;

[0144] 5) Place the rock sample on the installed bearing base and install the axial displacement sensor. During installation, observe the displacement value change on the computer to ensure that the displacement reading is near the zero point;

[0145] 6) Select force (large)-displacement experiment on the computer experimental system, the displacement loading rate is 0.002mm / s, and other parameters are set at the same time, displacement limit: 4mm, force limit: 300kN;

[0146] 7) After checking that the loading device is correct, carry out pre-loading and subsequent experiments;

[0147] 8) After the experiment, export the experimental data on the computer;

[0148] 9) Arrange all experimental equipment and turn off the operating system, computer, water valve and power supply;

[0149] The uniaxial compressive strength is calculated as follows:

[0150]

[0151] σ-uniaxial compressive strength

[0152] P- Maximum axial pressure when rock specimen fails

[0153] A – cross-sectional area of ​​the rock specimen;

[0154] The direct shear test process is as follows:

[0155] 1) Turn on the power and water valve and start the computer simultaneously;

[0156] 2) Turn on the operating system and start the low-pressure button to preheat the experimental system in a low-pressure state for 10 minutes;

[0157] 3) After preheating, press the high-voltage button to switch the experimental system to high-voltage state;

[0158] 4) placing the rock sample in the shearing device and fixing the shearing device simultaneously;

[0159] 5) Install the horizontal displacement sensor and observe the displacement value changes on the computer during installation to ensure that the displacement reading is near the zero point;

[0160] 6) Select the large-scale shear test on the computer experimental system, select displacement control as the experimental control mode, set the displacement loading rate to 0.005 mm / s, and set other parameters at the same time, displacement limit: 8 mm, normal force size: 20 kN, normal force loading rate: 0.5 kN / s, shear force limit: 200 kN;

[0161] 7) After checking that the loading device is correct, carry out vertical preloading, horizontal preloading, vertical operation and subsequent experiments;

[0162] 8) After the experiment, export the experimental data on the computer;

[0163] 9) Arrange all experimental equipment and turn off the operating system, computer, water valve and power supply;

[0164] Calculation method of rock shear strength:

[0165]

[0166] τ-shear strength

[0167] Q- Maximum shear force acting on the shear surface of the rock sample

[0168] A- shear surface area of ​​rock specimen.

[0169] In some embodiments, the rock is saturated with water, has varying water contents, or is dry.

[0170] In some embodiments, the temperature-controlled rock shear creep test method comprises the following steps:

[0171] S1. The uniaxial compressive strength σ (in MPa) of the rock sample is obtained through the uniaxial compression test, and the shear strength τ (in MPa) of the rock sample is obtained through the direct shear test;

[0172] S2, fixing the fixed pulley bracket and the fixed pulley, fixing the fixed pulley bracket and then installing the fixed pulley on the fixed pulley bracket;

[0173] S3, the acoustic emission sensor is installed on the second shear box, and the coupling agent is evenly applied on the collection end;

[0174] S4. Place the rock sample to be tested (100 mm in length, 100 mm in width, and 100 mm in height) on the upper surface of the second shear box and fit it to the acoustic emission sensor;

[0175] S5, open the door of the test box, and put the second shear box into the test box along the limit groove, at which time the lower end surface of the first shear box is in contact with the rock sample;

[0176] S6. Place the normal counterweight block, place the T-shaped pressure block in the pressure block transfer hole at the top of the test box, and place the normal counterweight block required for the shear creep experiment on the upper part of the T-shaped pressure block;

[0177] S7, fix the first level of horizontal counterweights, and fix the required horizontal counterweights for the next level in stages. After the shear creep deformation is in a stable state (the deformation is less than 0.01 mm within 24 hours), fix the mass of the required horizontal counterweights for the i-th level to the lower end of the steel wire. After the rock sample is destroyed, stop applying the horizontal counterweights.

[0178] S8. Record data. Continuously record the shear creep deformation every t hours and, after the specimen is destroyed, record the number of horizontal counterweights applied at the time of destruction.

[0179] In some embodiments, a saturated rock sample is placed, and a coupling agent is evenly applied to the collection end of the acoustic emission sensor so that the sensor is closely attached to the surface of the saturated rock sample wrapped with a plastic wrap;

[0180] Repeat steps S5 to S8 to carry out a room temperature shear creep test of a saturated sample;

[0181] In some embodiments, rock samples with different moisture contents are placed, and coupling agent is evenly applied to the collection end of the acoustic emission sensor, and the sensor is closely attached to the surface of the rock samples with different moisture contents wrapped with plastic wrap;

[0182] Repeat steps S5 to S8 to carry out room temperature shear creep experiments on samples with different moisture contents;

[0183] In some embodiments, a dry rock sample is placed, and a coupling agent is evenly applied to the collection end of the acoustic emission sensor and the sensor is closely attached to the surface of the dry rock sample;

[0184] Repeat steps S5 to S8 to carry out room temperature shear creep experiments on dry rock samples.

[0185] In some embodiments, the refrigeration control switch of the temperature control box is turned on, and the temperature is adjusted to the expected temperature T1°C. When the temperature reaches T1°C, it is maintained at this temperature for t1 hour. The refrigeration control switch is turned off and the heating control switch is turned on. The temperature is adjusted to the expected temperature T2°C. When the temperature of the temperature control table reaches T2°C, it is maintained at this temperature for t2 hours. The above operation is repeated until the sample is destroyed. In this way, shear creep experiments of rock samples at different temperatures are carried out.

[0186] In some embodiments, the experimental data are collated and analyzed, and the following analysis can be made through the shear creep experiments of rocks under different temperature environments: (1) Under the same temperature environment, the long-term strength of the samples in the dry state and the samples in the saturated state are compared, and the influence of the sample state on its long-term strength is analyzed; (2) Under the same temperature environment, the long-term strength of the samples with different moisture contents is compared, and the influence of the moisture content on its long-term strength is analyzed; (3) The relationship between the shear strain and time corresponding to the dry samples and the saturated samples under different temperature conditions is plotted in the same coordinate system, with time as the horizontal axis and shear strain as the vertical axis; (4) The relationship between the shear strain and time corresponding to the samples with different moisture contents under different temperature conditions is plotted in the same coordinate system, with time as the horizontal axis and shear strain as the vertical axis.

[0187] Based on the same inventive concept, the present invention also provides a temperature-controllable rock shear creep instability failure prediction method, comprising the following steps:

[0188] The rock shear creep experiment was carried out according to the above method;

[0189] Among them, during the rock shear creep process, an acoustic emission collector is used to collect the acoustic emission signals released during the rock shear creep process;

[0190] The infrasound wave acquisition instrument is used to collect the infrasound wave signal in the process of rock shear creep;

[0191] The instability and failure of rocks are predicted by using acoustic emission signals and / or infrasound signals.

[0192] In some embodiments, the prediction of rock instability and failure using acoustic emission signals and / or infrasound signals specifically includes:

[0193] The acoustic emission signal is processed to obtain the acoustic emission event rate, acoustic emission ringing count, acoustic emission energy, and acoustic emission main frequency;

[0194] The infrasound wave signal is processed to obtain the infrasound wave energy rate and the infrasound wave sub-dominant frequency respectively;

[0195] Among them, when a sudden increase signal appears in the acoustic emission event rate within a unit time, and / or a surge signal appears in the acoustic emission ring count within a unit time, and / or a sudden surge phenomenon appears in the acoustic emission energy within a unit time, and / or a sudden surge phenomenon appears in the infrasonic wave energy rate within a unit time, and / or an accumulation phenomenon appears in the main frequency of the acoustic emission in the frequency band of 200 to 250 kHz, and / or an accumulation phenomenon appears in the sub-main frequency of the infrasonic wave in the frequency band of 5 to 7 Hz, it is predicted that the rock will become unstable and fail.

[0196] Specifically, the acoustic emission signal and infrasound wave signal released by the sample during the experiment can be monitored in real time by an acoustic emission collector and an infrasound wave collector. The acoustic emission signal and infrasound wave signal released by the sample can be processed by a computing unit (specifically a computer) to obtain acoustic emission parameters such as acoustic emission event rate, acoustic emission ringing count, acoustic emission energy, and acoustic emission main frequency, and infrasound wave parameters such as infrasound wave energy rate and infrasound wave sub-main frequency. The instability and failure of the sample can be predicted based on the distribution characteristics of the acoustic emission parameters and infrasound wave parameters.

[0197] The prediction method of specimen instability failure is as follows:

[0198] (1) Acoustic emission prediction method

[0199] 1) Acoustic emission event rate prediction

[0200] 2) Acoustic emission ring count prediction

[0201] 3) Acoustic emission energy prediction

[0202] 4) Prediction of acoustic emission main frequency

[0203] (2) Infrasound prediction method

[0204] 1) Infrasound energy rate prediction

[0205] 2) Prediction of sub-dominant frequency of infrasound

[0206] (3) Combined prediction method of acoustic emission and infrasound

[0207] The combined prediction method of acoustic emission event rate, ring count, energy, dominant frequency, infrasonic energy rate, and sub-dominant frequency for predicting the instability failure of a specimen is as follows:

[0208] (1) Acoustic emission prediction method

[0209] 1) Acoustic emission event rate prediction: The acoustic emission event rate is any wave impact signal of local changes in the material that generates acoustic emission and is commonly used to evaluate the activity and localization concentration of the fracture source. Using Matlab software programming, calculate the number of acoustic emission events per second, that is, the acoustic emission event rate. The cumulative acoustic emission event number is the sum of the acoustic emission event rates per second. Plot the acoustic emission event rate and the cumulative acoustic emission event number in the same coordinate system, as Figure 5 shown. In the section from A1 to A2, the cumulative acoustic emission event number curve approximately rises slowly in a straight line. The acoustic emission event rate is distributed within the interval from E1 to E2 (E1 < E2) with a small fluctuation amplitude, indicating that the acoustic emission event rate is in a relatively quiet period, and at this time the specimen is in a relatively stable stage; after point A2, the cumulative acoustic emission event number curve rises sharply, and the acoustic emission event rate is also in a sharp rise period and a large number of sudden increase signals appear. At point A, the acoustic emission event rate reaches the maximum value of E3 (E2 << E3), indicating that the acoustic emission signals inside the specimen are relatively active during this stage, and the internal cracks of the specimen will continue to develop and expand until complete failure; after point A, the cumulative acoustic emission event number curve grows slowly, and the acoustic emission event rate drops sharply, so the acoustic emission signals inside the specimen are weak, indicating that the specimen has been completely damaged; the acoustic emission event rate generally goes through three stages: relatively quiet period - sharp rise period - sharp drop period, indicating that the development of internal cracks in the specimen goes through: stable development stage - unstable fracture development stage - post-fracture stage. Therefore, the sudden increase signal of the acoustic emission event rate ( Figure 5 point A in the figure) can be used as an important characteristic information of the specimen failure precursor.

[0210] 2) Acoustic emission ring count prediction: The acoustic emission ring count is the number of oscillations of the acoustic emission signal exceeding a certain set threshold signal and is used to evaluate the strength of acoustic emission activity. Similarly, use Matlab software programming to calculate the number of oscillations exceeding the threshold signal per second. The cumulative acoustic emission ring count is the sum of the acoustic emission ring counts per second. Plot the acoustic emission ring count and the cumulative acoustic emission ring count in the same coordinate system, as Figure 6As shown, in the B1 - B2 section, the cumulative ringing count curve approximately increases slowly in a straight line, and the acoustic emission ringing count has basically no fluctuations. It is within the F1 - F2 interval (F1 < F2), indicating that the internal cracks of the specimen develop relatively stably in this stage and the specimen does not fail; after point B2, the growth rate of the cumulative ringing count curve increases significantly, the ringing count rises sharply and a large number of surge signals appear. At point B, the ringing count reaches the maximum value of F3 (F2 << F3), indicating that the internal acoustic emission activity of the specimen increases, predicting that the main fracture of the specimen is about to occur; after point B, the acoustic emission ringing count drops sharply, indicating that the internal acoustic emission activity of the specimen weakens, predicting that the specimen has been completely damaged; the overall acoustic emission ringing count experiences: a quiet period - a sharp rise period - a sharp decline period, indicating that the acoustic emission activity intensity experiences: a quiet period - a rise period - a decline period. Therefore, the surge signal of the acoustic emission ringing count ( Figure 6 point B in it) can be used as an important precursor feature of the main fracture generation.

[0211] 3) Prediction of acoustic emission energy: Acoustic emission energy is the area under the detection envelope of the acoustic emission event signal, which can reflect the relative energy and intensity. Similarly, use Matlab software to program and calculate the acoustic emission energy generated by the failure of each specimen per second. The cumulative acoustic emission energy is the sum of the acoustic emission energy per second, and the acoustic emission energy and the cumulative acoustic emission energy are plotted in the same coordinate system, as Figure 7 shown. In the C1 - C2 section, the cumulative acoustic emission energy curve approximately rises slowly in a straight line, and the acoustic emission energy is relatively low. It is within the G1 - G2 interval (G1 < G2), indicating that the specimen strength is relatively low and has not reached the peak strength; after point C2, the growth rate of the cumulative acoustic emission energy curve increases sharply, and the acoustic emission energy also rises sharply. At point C, the acoustic emission energy reaches the maximum value of G3 (G2 << G3) and there is a "jumping" type of surge phenomenon in energy, indicating that the specimen strength gradually increases until the peak strength of the specimen; after point C, the acoustic emission energy drops sharply, indicating that the specimen strength is relatively low; the overall acoustic emission energy experiences: a relatively quiet period - a sharp rise period - a sharp decline period, indicating that the specimen strength experiences: a stable increase stage - a sharp increase stage - a sharp decline stage. Therefore, the "jumping" type of surge phenomenon of the acoustic emission energy ( Figure 7 point C in it) can be used as an important characteristic information of the precursor of the main fracture of the specimen.

[0212] 4) Prediction of acoustic emission main frequency: Use Matlab software to perform a fast Fourier transform (FFT) on the original waveform file of the rock specimen to obtain the main frequency of the specimen acoustic emission signal. The relationship between the acoustic emission main frequency and the shear creep time is plotted in the same coordinate system, as Figure 8 shown. There is a main frequency band in the acoustic emission main frequency, which is 200 - 250 KHz. Therefore, the phenomenon of the accumulation of the acoustic emission main frequency in the 200 - 250 KHz frequency band can be used as an important characteristic of the precursor of the specimen failure.

[0213] Based on the above analysis, the sudden increase signal of the acoustic emission event rate, and / or, the sudden increase signal of the acoustic emission ring count, and / or, the sudden increase phenomenon of the acoustic emission energy in a stepped manner, and / or, the accumulation phenomenon of the main frequency of the acoustic emission in the frequency band of 200 - 250 KHz can be used as important characteristic information for the precursor of the instability failure of the specimen.

[0214] (2) Infrasound prediction method

[0215] 1) Infrasound energy rate prediction: Define the rate of change of the energy of the infrasound signal with time as the infrasound energy rate. The infrasound energy rate is the area under the envelope curve of the amplitude of the infrasound voltage versus time per second. The energy rate can better express the intensity of the occurrence of the infrasound signal. Similarly, use Matlab software to program and calculate the infrasound energy rate generated by the failure of each specimen per second. The cumulative infrasound energy rate is the sum of the infrasound energy rates per second, and plot the infrasound energy rate and the cumulative infrasound energy rate in the same coordinate system. As Fig. 9 shown, in the D1 - D2 section, the cumulative infrasound energy rate curve approximately rises slowly in a straight line, and the infrasound energy rate is in a relatively quiet period. Being in the M1 - M2 interval (M1 < M2) indicates that the infrasound signal is relatively weak at this time; after point D2, the cumulative infrasound energy rate curve rises sharply, and the infrasound energy rate also increases sharply. At point D, the infrasound energy rate reaches the maximum value of M3 (M2 << M3) and there is a phenomenon of a sudden increase in the infrasound energy rate in a stepped manner, indicating that the infrasound signal is relatively strong at this time; after point D, the infrasound energy rate drops sharply, indicating that the infrasound signal is relatively weak at this time; the overall change of the infrasound energy rate goes through: a relatively quiet period - a sharp rise period - a sharp drop period, indicating that the infrasound signal goes through: a quiet period - a rise period - a drop period. Therefore, the phenomenon of a sudden increase in the infrasound energy rate in a stepped manner ( Fig. 9 point D in it) can be used as important characteristic information for the precursor of the main fracture of the specimen.

[0216] 2) Infrasound sub - main frequency prediction: By synchronously adding an infrasound device during the experiment, the infrasound signal released by the specimen during the experiment can be monitored in real - time. Through processing the infrasound signal, the infrasound sub - main frequency of the specimen can be obtained. Plot the relationship between the infrasound sub - main frequency and the shear creep time in the same coordinate system. As Fig.10 shown, there is a main frequency band in the infrasound sub - main frequency, which is 5 - 7 Hz. Therefore, the accumulation phenomenon of the infrasound sub - main frequency in the 5 - 7 Hz frequency band can be used as an important characteristic of the precursor of the specimen failure.

[0217] Based on the above analysis, the phenomenon of a sudden increase in the infrasound energy rate in a stepped manner, and / or, the accumulation phenomenon of the infrasound sub - main frequency in the 5 - 7 Hz frequency band can be used as important characteristic information for predicting the precursor of the instability failure of the specimen.

[0218] (3) Acoustic emission and infrasound combined prediction method

[0219] Furthermore, by jointly analyzing the acoustic emission signals and infrasound signals generated by rock samples during shear creep experiments, the shortcomings of using a single acoustic signal analysis can be compensated, and the joint analysis method can more accurately predict the precursors of rock sample instability and failure. The obtained acoustic emission parameters and infrasound parameters are plotted in the same coordinate system, such as Fig.11 As shown in the figure, the sudden increase signal of acoustic emission event rate, the surge signal of acoustic emission ringing count, the leap-like surge phenomenon of acoustic emission energy and infrasonic energy rate, the accumulation phenomenon of acoustic emission main frequency in the frequency band of 200-250KHz, and the accumulation phenomenon of infrasonic sub-main frequency in the frequency band of 5-7Hz can be combined with each other and used as precursor signals for predicting the instability and failure of rock samples.

[0220] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A temperature-controllable rock shear creep experimental device, characterized in that: include: A shearing unit comprising: An experimental box, wherein a first shear box and a second shear box are disposed in the experimental box, and the first shear box and the second shear box are used to place the rock to be tested; The first shear box is connected to first cooling / heating pipes on both sides respectively; The two sides of the second shear box are respectively connected with second cold / hot pipes; A temperature control unit, comprising a temperature control box, wherein a temperature-controllable energy storage medium is arranged in the temperature control box; The end of the first cooling / heating pipe away from the first shear box passes through the experimental box and is connected to the temperature control box; The end of the second cooling / heating pipe away from the second shear box passes through the experimental box and is connected to the temperature control box; a normal loading unit, which is used to apply a normal force to the first shear box; a horizontal loading unit, which is used to apply a shear force to the second shear box; A displacement sensor, used for monitoring the horizontal displacement of the first shear box; A sound wave unit comprising: An acoustic emission sensor, located on the second shear box and used for monitoring the acoustic emission signal during rock shear creep; An infrasound sensor is used to monitor the infrasound signal during rock shear creep; An acoustic emission collector, which is communicatively connected to the acoustic emission sensor to collect acoustic emission signals; An infrasound wave collector, which is communicatively connected with the infrasound wave sensor to collect infrasound wave signals; The calculation unit is respectively connected to the acoustic emission collector and the infrasound wave collector for communication, and calculates the acoustic emission signal and the infrasound wave signal.

2. The temperature-controllable rock shear creep experimental device according to claim 1, characterized in that: The normal loading unit comprises: A T-shaped pressure block, comprising a vertical pressure block arranged vertically and a horizontal pressure block arranged horizontally, wherein the lower end of the vertical pressure block is connected to the first shear box, and the upper end of the vertical pressure block passes through the test box and is connected to the horizontal pressure block; The normal counterweight block is located on the horizontal pressure block.

3. The temperature-controllable rock shear creep experimental device according to claim 1, characterized in that: The horizontal loading unit comprises: A fixed pulley, which is located outside the experimental box; A steel wire, one end of which is fixed to one side of the first shear box, and the other end of which is passed around a fixed pulley and connected to a horizontal counterweight; The horizontal counterweight block is used to drive the first shear box to move in the horizontal direction.

4. The temperature-controllable rock shear creep test device according to claim 1, characterized in that: First temperature sensors are respectively provided on both sides of the first shear box, and the first temperature sensors are used to monitor the temperature inside the first shear box; Second temperature sensors are respectively provided on both sides of the second shear box, and the second temperature sensors are used to monitor the temperature inside the second shear box.

5. The temperature-controllable rock shear creep test device according to claim 1, characterized in that: The experimental box comprises a box body and a box door, and the box door is rotatably connected to the box body to open or close the box body.

6. The temperature-controllable rock shear creep test device according to claim 1, characterized in that: A limiting block is arranged in the experimental box, a limiting groove is arranged on the limiting block, and the second shear box is arranged in the limiting groove.

7. A temperature-controllable rock shear creep test method, characterized in that: The following steps are involved: Providing a temperature-controllable rock shear creep experimental device as described in any one of claims 1 to 6; The rock to be tested is placed between the first shear box and the second shear box, and the acoustic emission sensor is closely attached to the rock surface; Using a temperature control box to control the energy storage medium to reach a set temperature, so that the first shear box and the second shear box are at the set temperature; applying a normal force to the first shear box; Apply shear force to the second shear box step by step. After applying each level of shear force, keep the shear force constant and observe and record the shear creep deformation of the rock. After the shear creep deformation is stable, apply the next level of shear force until the rock is sheared and destroyed, and then stop the experiment. Calculate the rock shear strain. The shear strain calculation formula is: Where: γ is the shear strain, Δx is the shear creep deformation, and L is the length of the rock.

8. The temperature-controlled rock shear creep test method according to claim 7, characterized in that: The normal loading unit includes a T-shaped pressure block and a normal counterweight block; A normal force is applied to the first shear box using a normal counterweight, wherein the mass of the normal counterweight is calculated according to the following formula: Where: m1 is the required normal counterweight mass, σ is the uniaxial compressive strength of rock obtained through uniaxial compression test, A is the area of ​​the lower end surface of the first shear box, g is the gravitational acceleration, b is the percentage of the required uniaxial compressive strength, and the value range of b is 10-60%; The horizontal loading unit comprises: a fixed pulley, a steel wire and a horizontal counterweight block, and the horizontal counterweight block is used to apply shear force to the second shear box step by step; Among them, the mass of the first-level horizontal counterweight is: Where: m2 is the mass of the first-level horizontal counterweight required, τ is the shear strength of the rock obtained through the direct shear test, A is the area of ​​the lower end surface of the first shear box, c1 is the percentage of the shear strength occupied by the first-level shear creep test, the value range of c1 is 30-95%, and g is the acceleration of gravity; The mass of the horizontal counterweight required for level i is: Where: m i is the mass of the i-th level counterweight block to be applied, i=2, 3...n; m i-1 is the mass of the horizontal ballast block applied at level i-1; c i is the percentage of shear strength accounted for by the i-th level shear creep test; c i >c i-1 ; c i The value range of is 30~95%; τ is the shear strength of rock obtained through direct shear test, A is the area of ​​the lower end surface of the first shear box, and g is the gravitational acceleration; The rock is saturated with water, has different water contents or is dry.

9. A temperature-controllable rock shear creep instability failure prediction method, characterized in that: The following steps are involved: Carry out rock shear creep test according to the method of claim 7 or 8; Among them, during the rock shear creep process, an acoustic emission collector is used to collect the acoustic emission signals released during the rock shear creep process; The infrasound wave acquisition instrument is used to collect the infrasound wave signal in the process of rock shear creep; The instability and failure of rocks are predicted by using acoustic emission signals and / or infrasound signals.

10. The temperature-controllable rock shear creep instability failure prediction method according to claim 9, characterized in that: The prediction of rock instability and failure is carried out using acoustic emission signals and / or infrasound signals, including: The acoustic emission signal is processed to obtain the acoustic emission event rate, acoustic emission ringing count, acoustic emission energy, and acoustic emission main frequency; The infrasound wave signal is processed to obtain the infrasound wave energy rate and the infrasound wave sub-dominant frequency respectively; Among them, when a sudden increase signal appears in the acoustic emission event rate within a unit time, and / or a surge signal appears in the acoustic emission ring count within a unit time, and / or a sudden surge phenomenon appears in the acoustic emission energy within a unit time, and / or a sudden surge phenomenon appears in the infrasonic wave energy rate within a unit time, and / or an accumulation phenomenon appears in the main frequency of the acoustic emission in the frequency band of 200 to 250 kHz, and / or an accumulation phenomenon appears in the sub-main frequency of the infrasonic wave in the frequency band of 5 to 7 Hz, it is predicted that the rock will become unstable and fail.

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