A quantitative method for precisely calculating the temporal and spatial rock-breaking laws of shock waves

Abstract

The present invention discloses a quantitative method for finely calculating the temporal and spatial rock-breaking law of shock waves, which includes the following steps: building a stress, acoustic emission, and CT integrated experimental system to conduct a uniaxial loading failure experiment on a rock mass; performing a three-dimensional scanning of the sample by CT to determine the morphology and spatial position of the rock mass load fracture source; collecting shock wave data generated by the rock sample fracture during the loading process, and decomposing it into P waves and S waves; establishing a refined numerical model according to the rock sample size and the fracture source morphology; loading the P waves and S waves with different displacement vector radiation patterns obtained in step 3 to the fracture source of the numerical model established in step 4 according to their inherent distribution characteristics; collecting PPV at different spatial positions from the fracture source; and revealing the law of shock wave damage to the rock mass from the time dimension based on the PPV failure criterion. The method of the present invention can finely calculate the damage of the shock wave generated by the coal rock fracture to the rock mass at each time and each spatial position, and play a guiding role in the targeted prevention and control of rock burst or rock burst.

Description

Technical Field

[0001] The present invention specifically relates to the technical field of rock burst prevention and control, and specifically is a quantitative method for precisely calculating the temporal and spatial rock breaking laws of shock waves. Background Art

[0002] Rock burst is a sudden and violent destructive dynamic phenomenon caused by the instantaneous release of elastic deformation energy of coal and rock mass around the mine tunnel, which often causes equipment damage and casualties. Many scholars at home and abroad believe that rock burst is the result of the superposition of dynamic and static loads. A relatively complete system has been formed for the study of static loads, but the dynamic loads are difficult to study due to the complex action process, and the relevant research results are still immature.

[0003] As the source of dynamic load, the vibration wave generated by coal-rock mass fracture plays an important role in inducing rock burst. Relevant scholars have studied the destructive instability characteristics of coal-rock mass under the conditions of dynamic loads such as stress waves based on impact theory, dynamic and static load superposition theory, and separated Hopkinson bar. 3D The propagation and attenuation characteristics of shock waves in coal and rock mass, as well as the intrinsic damage mechanism of coal and rock mass under the action of shock waves, were simulated and studied by methods such as [1] and [2] . However, previous studies mainly applied shock waves in a fixed direction, which is inconsistent with the characteristics of the P-wave and S-wave radiation modes in shock waves, and cannot accurately reveal the response characteristics of shock waves to rock mass damage; at the same time, current technology only conducts qualitative analysis of the action law of shock waves from a time or space perspective, and cannot more accurately and quantitatively reveal the damage characteristics of shock waves to rock mass. It can be seen that it is necessary to propose a method for finely quantifying the damage law of shock waves to rock mass, and based on this, carry out targeted support for tunnels to improve tunnel stability. Summary of the invention

[0004] To this end, the present invention proposes a quantitative method for precisely calculating the temporal and spatial rock-breaking laws of shock waves to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a quantitative method for precisely calculating the temporal and spatial rock breaking law of shock waves, comprising the following steps:

[0006] Step 1: Build an integrated experimental system of stress, acoustic emission and CT to conduct uniaxial loading failure experiments on rock mass;

[0007] Step 2: Use CT to perform three-dimensional scanning of the sample to determine the shape and spatial position of the rock mass load fracture source;

[0008] Step 3: Collect the shock wave data generated by the rock sample fracture during the loading process and decompose it into P waves and S waves;

[0009] Step 4: Establish a refined numerical model based on the rock sample size and fracture source morphology;

[0010] Step 5: Load the P-wave and S-wave with different displacement vector radiation patterns obtained in step 3 to the rupture source of the numerical model established in step 4 according to their inherent distribution characteristics;

[0011] Step 6: Collect PPV at different spatial locations from the fracture source; and reveal the law of rock mass damage by vibration waves from the time dimension based on the PPV damage criterion;

[0012] Step 7: According to the stress F distribution law, calculate the energy U distribution characteristics at different spatial positions from the rupture source, and reveal the law of rock mass destruction by shock waves from the spatial dimension;

[0013] Step 8: Based on the PPV collected in step 6 and the energy calculated in step 7, a three-dimensional visual dynamic cloud map is constructed to reveal the law of the effect of the vibration wave on the rock mass from the joint dimension of time and space.

[0014] Further, preferably, in step 1, the mechanical loading system can perform uniaxial loading on the standard rock sample;

[0015] Three-dimensional CT reconstruction uses X-rays to scan the sample, and three-dimensional reconstruction of the scanned data can obtain the internal fracture source of the sample;

[0016] The acoustic emission monitoring system can convert the vibration generated by rock sample fracture into shock wave signals.

[0017] Furthermore, preferably, in step 3, the shock wave generated by the rock sample rupture can be decomposed into P waves and S waves by using time-frequency redistribution and empirical mode decomposition.

[0018] Further, as a preference, in step 4, the rock sample model established is consistent with the sample subjected to the uniaxial loading test in step 1;

[0019] The established rupture source model is consistent with the rupture source morphology extracted after CT scanning and three-dimensional reconstruction in step 2.

[0020] Further, preferably, in step 5, the rupture source shape determines the displacement vector radiation pattern of the P wave and the S wave in the shock wave.

[0021] Further, as a preference, when the rupture source is shear rupture, the shock wave displacement vector radiation pattern is:

[0022]

[0023] When the rupture source is tensile rupture, the shock wave displacement vector radiation pattern is:

[0024]

[0025] Among them, D lis the P wave displacement, D m is the SV wave displacement, D n is the SH wave displacement, ρ is the rock density, υ α is the P wave velocity, υ β is the shear wave velocity, d is the distance from the earthquake source, t is the propagation time of the shock wave, θ is the angle between the displacement vector and the z axis, is the angle between the displacement vector and the x-axis, and f is the force at a distance d from the earthquake source.

[0026] Further, preferably, in step 6, the PPV is the peak particle vibration velocity of the vibration wave during the entire loading process.

[0027] Further, preferably, in step 7, the minimum energy required to destroy the rock mass is:

[0028]

[0029] Where E is the elastic modulus of rock mass, δ c is the uniaxial compressive strength of rock;

[0030] The calculation formula of the spatial position energy U is:

[0031]

[0032] Among them, F is the elastic modulus of the rock mass, ξ is the strain generated by the rock mass under the action of force. When the spatial position energy of the rock mass is greater than the minimum energy required for rock mass destruction, that is, the energy storage limit of the rock mass, the rock mass will be destroyed.

[0033] Furthermore, as a preferred embodiment, in the constructed three-dimensional visualization dynamic cloud map of PPV and energy in step 8, the parameters PPV and energy U determine the rock destruction characteristics at different times and different spatial positions, and a comprehensive analysis of the two can quantify the law of rock destruction by vibration waves.

[0034] The present invention adopts the above technology and has the following beneficial effects compared with the existing technology:

[0035] 1. The present invention builds an integrated experimental system of loading stress, acoustic emission, and CT to carry out a rock load fracture experiment; a three-dimensional scanning of the sample is performed through CT to determine the shape and spatial position of the rock load fracture source; the acoustic emission sensor installed on the surface of the sample is used to collect the waveform of the vibration wave generated by the coal and rock fracture in real time, and the vibration wave generated by the corresponding fracture source is split to obtain P wave and S wave; a refined numerical model is constructed according to the sample size and the fracture source shape; P wave and S wave are loaded to the fracture source according to the distribution characteristics of the spatial displacement field of P wave and S wave, and dynamic load simulation calculation is carried out to obtain PPV of spatial positions at different distances from the fracture source; the temporal and spatial rock breaking law of the vibration wave is determined according to the PPV rock failure criterion, spatial energy distribution, and a three-dimensional visualization cloud map based on the two.

[0036] 2. The present invention can precisely calculate the damage of the shock waves generated by coal and rock fracture to the rock mass at each time and each spatial position, and play a guiding role in the targeted prevention and control of rock burst or rock burst. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 1 is a flow chart for implementing the method of the present invention;

[0038] Figure 2 Schematic diagram of an integrated system of mechanical loading, three-dimensional CT scanning, and acoustic emission monitoring in an embodiment of the present invention;

[0039] Figure 3 This is a typical shear fracture source diagram in an embodiment of the present invention;

[0040] Figure 4 A refined numerical model established for an embodiment of the present invention;

[0041] Figure 5 The full PPV results and sample energy cloud map are loaded for the center position of the embodiment of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in 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.

[0043] Example: Please refer to the attached Figure 1-5 The present invention provides a technical solution: a quantitative method for precisely calculating the temporal and spatial rock-breaking law of shock waves, characterized in that it comprises the following steps:

[0044] Step 1: Build an integrated experimental system of stress, acoustic emission and CT to conduct uniaxial loading failure experiments on rock mass;

[0045] Specifically, three-dimensional CT scanning can be used to reconstruct the mechanically loaded specimen and obtain the internal fracture source; at the same time, the acoustic emission monitoring system can convert the vibration generated by the fracture of the rock sample into a shock wave signal;

[0046] Step 2: Use CT to perform three-dimensional scanning of the sample to determine the shape and spatial position of the rock mass load fracture source;

[0047] Step 3: Collect the shock wave data generated by the rock sample fracture during the loading process and decompose it into P waves and S waves;

[0048] Specifically, it can be decomposed into P waves and S waves using time-frequency redistribution and empirical mode decomposition;

[0049] Step 4: Establish a refined numerical model based on the rock sample size and fracture source morphology;

[0050] Specifically, the established rock sample model is consistent with the sample subjected to the uniaxial loading test in step 1; the established fracture source model is consistent with the fracture source morphology extracted after CT scanning and three-dimensional reconstruction in step 2;

[0051] Step 5: Load the P-wave and S-wave with different displacement vector radiation patterns obtained in step 3 to the rupture source of the numerical model established in step 4 according to their inherent distribution characteristics;

[0052] Specifically, the rupture source shape determines the displacement vector radiation pattern of the P wave and S wave in the shock wave. When the rupture source is shear rupture, the shock wave displacement vector radiation pattern is:

[0053]

[0054] When the rupture source is tensile rupture, the shock wave displacement vector radiation pattern is:

[0055]

[0056] Among them, D l is the P wave displacement, D m is the SV wave displacement, D n is the SH wave displacement, ρ is the rock density, υ α is the P wave velocity, υ β is the shear wave velocity, d is the distance from the earthquake source, t is the propagation time of the shock wave, θ is the angle between the displacement vector and the z axis, is the angle between the displacement vector and the x-axis, and f is the force at a distance d from the earthquake source;

[0057] Step 6: Collect PPV at different spatial locations from the fracture source; and reveal the law of rock mass damage by vibration waves from the time dimension based on the PPV damage criterion;

[0058] Specifically, PPV is the peak particle vibration velocity of the vibration wave during the entire loading process; the degree of rock mass damage caused by different PPVs is shown in the table below. It can be seen that when PPV is greater than the basic threshold of 300 mm / s, the rock mass is damaged at the PPV moment;

[0059] PPV range (mm / s) Less than 300 300-500 More than 500 Degree of damage Loose rock fall New cracks appear Macro damage

[0060] Step 7: According to the stress F distribution law, calculate the energy U distribution characteristics at different spatial positions from the rupture source, and reveal the law of rock mass destruction by shock waves from the spatial dimension;

[0061] Specifically, the minimum energy required to destroy the rock mass is:

[0062]

[0063] Where E is the elastic modulus of rock mass, δ c is the uniaxial compressive strength of rock;

[0064] The calculation formula of the spatial position energy U is:

[0065]

[0066] Among them, F is the elastic modulus of the rock mass, ξ is the strain generated by the rock mass under the action of force. When the spatial position energy of the rock mass is greater than the minimum energy required for rock mass failure, that is, the energy storage limit of the rock mass, the rock mass will be destroyed.

[0067] Step 8: Based on the PPV collected in step 6 and the energy calculated in step 7, a three-dimensional visual dynamic cloud map is constructed to reveal the law of the effect of the vibration wave on the rock mass from the joint dimensions of time and space;

[0068] Specifically, in the constructed three-dimensional visualization dynamic cloud map of PPV and energy, the parameters PPV and energy U determine the rock failure characteristics at different times and spatial positions. The comprehensive analysis of the two can quantify the law of rock destruction caused by vibration waves.

[0069] An embodiment of the present invention is further described below in conjunction with the accompanying drawings:

[0070] The embodiment of the present invention is based on the uniaxial loading failure experiment of rock mass. The method of the present invention is used to process and analyze the original data, and the law of the effect of the vibration wave on the rock mass can be detected in real time from the joint dimension of time and space. The specific process is as follows: Figure 1 As shown;

[0071] Schematic diagram of the stress, acoustic emission, and CT integrated system built for the uniaxial loading experiment. Figure 2 As shown;

[0072] The specimens scanned by CT after loading and failure were reconstructed in three dimensions, and the fracture sources were extracted. Typical shear fracture sources are as follows: Figure 3 As shown;

[0073] The refined numerical model established based on the reconstructed fracture source morphology and the original sample position relationship is as follows: Figure 4 As shown;

[0074] The P-wave and S-wave are loaded to the rupture source according to their inherent propagation modes, and the PPV and stress field characteristics of the entire loading process are collected. Based on this, the energy size at any position of the sample is calculated. The PPV results of the entire loading process at the center position are as follows: Figure 5 As shown in a, after loading is completed, the energy cloud diagram of the sample is as follows Figure 5 As shown in b.

[0075] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A quantitative method for precisely calculating the temporal and spatial rock-breaking laws of shock waves, characterized in that: It includes the following steps: Step 1: Build an integrated experimental system of stress, acoustic emission and CT to conduct uniaxial loading failure experiments on rock mass; Step 2: Use CT to perform three-dimensional scanning of the sample to determine the shape and spatial position of the rock mass load fracture source; Step 3: Collect the shock wave data generated by the rock sample fracture during the loading process and decompose it into P waves and S waves; Step 4: Establish a refined numerical model based on the rock sample size and fracture source morphology; Step 5: Load the P-wave and S-wave with different displacement vector radiation patterns obtained in step 3 to the rupture source of the numerical model established in step 4 according to their inherent distribution characteristics; Step 6: Collect PPV at different spatial locations from the fracture source; and reveal the law of rock mass damage by vibration waves from the time dimension based on the PPV damage criterion; Step 7: Based on the stress F Distribution law, calculate the energy at different spatial locations from the rupture source U Distribution characteristics, revealing the law of rock mass destruction by shock waves from the spatial dimension; Step 8: Based on the PPV collected in step 6 and the energy calculated in step 7, a three-dimensional visual dynamic cloud map is constructed to reveal the law of the effect of the vibration wave on the rock mass from the joint dimensions of time and space; In step 1, the mechanical loading system can perform uniaxial loading on the standard rock sample; Three-dimensional CT reconstruction uses X-rays to scan the sample, and three-dimensional reconstruction of the scanned data can obtain the internal fracture source of the sample; The acoustic emission monitoring system can convert the vibration generated by rock sample fracture into shock wave signals; In step 5, the rupture source shape determines the displacement vector radiation pattern of the P wave and the S wave in the shock wave; When the rupture source is shear rupture, the shock wave displacement vector radiation pattern is: ， When the rupture source is tensile rupture, the shock wave displacement vector radiation pattern is: ， in, is the P-wave displacement, is the SV wave displacement, is the SH wave displacement, is the rock density, is the P-wave velocity, is the shear wave velocity, d is the distance from the earthquake source, t is the propagation time of the shock wave, is the angle between the displacement vector and the z-axis, is the angle between the displacement vector and the x-axis, is the force at a distance d from the earthquake source; In step 6, the PPV is the peak particle vibration velocity of the vibration wave during the entire loading process; In step 7, the minimum energy required to destroy the rock mass is: ， Where E is the elastic modulus of rock mass, is the uniaxial compressive strength of rock; The spatial position energy The calculation formula is: ， Where, F is the elastic modulus of rock mass, It is the strain generated by the rock mass under the action of force. When the spatial energy of the rock mass is greater than the minimum energy required for rock mass failure, that is, the energy storage limit of the rock mass, the rock mass will be destroyed.

2. According to claim 1, a quantitative method for precisely calculating the temporal and spatial rock-breaking law of shock waves is characterized by: In step 3, the shock wave generated by the rock sample rupture can be decomposed into P waves and S waves by using time-frequency redistribution and empirical mode decomposition.

3. According to claim 1, a quantitative method for precisely calculating the temporal and spatial rock-breaking law of shock waves is characterized by: In step 4, the rock sample model established is consistent with the sample subjected to the uniaxial loading test in step 1; The established rupture source model is consistent with the rupture source morphology extracted after CT scanning and three-dimensional reconstruction in step 2.

4. According to claim 1, a quantitative method for precisely calculating the temporal and spatial rock-breaking law of shock waves is characterized by: In the step 8, in the constructed three-dimensional visualization dynamic cloud map of PPV and energy, the parameters PPV and energy U determine the rock mass failure characteristics at different times and different spatial positions, and a comprehensive analysis of the two can quantify the law of rock mass failure by vibration waves.

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