Quantitative analysis method for initial damage of softening rock based on acoustic emission ring count

Abstract

The method for quantitatively analyzing initial damage of softening ore rock based on acoustic emission ring count includes the following steps: preparing softening ore rock test piece, respectively carrying out acoustic emission test under uniaxial compression condition to obtain axial displacement, load and acoustic emission parameter value of each ore rock test piece, calculating and analyzing initial compaction stress and acoustic emission parameter evolution characteristics of the ore rock test piece under uniaxial compression, defining damage variable of the softening ore rock based on the modified acoustic emission ring count, and constructing damage constitutive model of the softening ore rock in the initial compaction stage. The method for quantitatively analyzing initial damage of the softening ore rock can be associated with internal structure characteristics of the softening ore rock, the damage model assumes that the initial damage is not 0, the initial damage degree of the softening ore rock can be accurately and real-timely monitored, and scientific reference basis is provided for quantifying the initial damage of the softening ore rock and monitoring the strength evolution law in the mining process.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for quantitatively analyzing initial damage of mine rock, in particular to a method for quantitatively analyzing initial damage of easily-weathered mine rock based on acoustic emission ring count. BACKGROUND

[0002] Easily-weathered mine rock belongs to typical porous medium material, and due to the effects of high ground pressure, high water pressure and high ground temperature, etc. during its long diagenetic process, various-sized and shaped holes and cracks are easily formed inside, which have an influence on the strain change during loading process. Therefore, it is very crucial to quantitatively analyze the initial damage of easily-weathered mine rock, to provide the internal connection between damage development and strength evolution during loading, and to further analyze the mechanical properties of easily-weathered mine rock and maintain the stability of easily-weathered mine rock in mine.

[0003] Due to the influence of geological conditions, the underground mining environment is humid and has a large water content, and some rock bodies are easily weathered after absorbing water, which causes the weakening of physical and mechanical properties, thus leading to the decrease of surrounding rock strength and causing a significant impact on the stability of stope structure, endangering the safety of personnel and property during mining. At present, the methods for quantifying the initial damage of rock-like material include statistical damage simulation method and experimental determination method. The statistical damage simulation method describes the mesoscopic damage of porous medium material by using normal distribution or Weibull distribution, thereby establishing an initial damage quantification model of rock under uniaxial or triaxial compression, which can better reflect the damage change characteristics of rock. However, the defined damage variable is not related to the internal structure characteristics of the material itself, and the damage model assumes that the initial damage is 0, which is inconsistent with the actual situation (the internal structure of the rock material) and affects the accuracy of the initial damage quantification results and the judgment of the stability of stope structure. The experimental determination method quantitatively describes the mesoscopic damage inside the material by using CT, scanning electron microscope, microscope and other experimental methods, which can only quantitatively analyze the mesoscopic structure of each section of the material, and it is difficult to determine the development and change of cracks inside the material, and the damage evolution during the stress-strain process cannot be observed in real time, which has certain limitations. SUMMARY

[0004] In view of the above shortcomings of the prior art, the present application provides an initial damage quantification analysis method for easily-weathered mine rock based on acoustic emission ring count, which can be related to the internal structure characteristics of easily-weathered mine rock, consistent with the initial damage not being 0 in the damage model, and can monitor the damage evolution during the stress-strain process in real time, so as to accurately and real-timely monitor and quantitatively analyze the initial damage of easily-weathered mine rock, and obtain the stress-strain relationship during the initial compaction stage of easily-weathered mine rock, thereby providing a scientific reference for quantitatively analyzing the initial damage inside easily-weathered mine rock during mining.

[0005] To achieve the above object, the technical scheme adopted by the present application is as follows.

[0006] A method for quantitatively analyzing initial damage of softening rock based on acoustic emission ring count, comprising the following steps:

[0007] Step one, making rock test pieces, the rock test pieces are softening rock test pieces;

[0008] Step two, respectively performing acoustic emission test on the rock in step one under uniaxial compression condition, and obtaining axial displacement, load and acoustic emission parameter values of each rock test piece;

[0009] Step three, calculating and analyzing initial compaction stress and acoustic emission parameter evolution characteristics of softening rock under uniaxial compression;

[0010] Step four, proposing a damage variable of softening rock based on the modified acoustic emission ring count, and constructing a damage constitutive model of softening rock in the initial compaction stage, the specific process is as follows:

[0011] The compaction stress can be obtained by the crack volume strain method and numerical calculation in the elastic stage. According to the generalized Hooke's law, the relationship between stress and strain of an object under load can be expressed as follows:

[0012]

[0013] In the formula: σ1, σ2 and σ3 are the principal stresses in three directions, with the unit of MPa; ε1, ε2 and ε3 are the strains in the directions corresponding to the three principal stresses; E is the elastic modulus, with the unit of MPa; μ is the Poisson's ratio;

[0014] In this paper, the real strain ε v is used to replace the virtual volume strain, so the crack volume strain ε is obtained as follows:

[0015]

[0016] Further, the crack volume strain under uniaxial compression condition is:

[0017]

[0018] The crack initiation stress σ ci and the damage stress σ cd can be obtained by formula (3). The closure stress σ cc needs to be further calculated by numerical calculation, so the stress-strain relationship in the elastic stage can be approximately expressed as follows:

[0019] σ=Eε+a (4)

[0020] where σ is the axial stress with unit of MPa, ε is the axial strain, E is the elastic modulus in the real state with unit of MPa, and a is the intercept of the linear function on the σ axis. The value of a can be obtained by substituting the crack initiation stress σ ci and the corresponding strain ε ci into equation (4). The stress at which the linear function of equation (4) intersects the stress-strain curve for the first time is approximately taken as the compaction stress σ cc at which the cracks are closed.

[0021] Further, in step four, the damage variable of the argillized rock based on the modified acoustic emission ring count is proposed, and the damage constitutive model of the argillized rock in the initial compaction stage is constructed. The specific process is as follows: the acoustic emission ring count is selected to quantify the initial damage of the argillized rock, and the damage variable D of the rock sample at the end of the initial compaction stage is taken as 0, i.e., the initial damage is completely repaired in the compaction stage, so the initial damage can be simply expressed as:

[0022]

[0023] where D0 represents the initial damage when the strain of the sample is 0, σ cc and σ f are the compaction stress and the peak stress, respectively, with unit of MPa, and the damage variable at the i-th moment in the compaction stage is:

[0024]

[0025] where D i represents the damage variable of the rock sample at the i-th moment in the compaction stage, R i is the cumulative acoustic emission ring count at the i-th moment in the compaction stage, R cc is the sum of the acoustic emission ring counts in the compaction stage, and it can be seen that D i is a monotonically decreasing function greater than 0 in the compaction stage. According to the damage variable in the compaction stage, the equivalent elastic modulus E i of the rock sample at the i-th moment in the compaction stage is:

[0026]

[0027] where E is the real elastic modulus of the sample measured in the test. Based on the equivalent continuous medium mechanics, the stress-strain relationship in the compaction stage of the argillized rock is discussed separately, and the constitutive model of the sample in the compaction stage is further obtained through equation (7) as:

[0028]

[0029] where σ i represents the stress at the i-th moment in the compaction stage, and ε iis the strain at the i th moment of the compaction stage. Substituting formula (5) into formula (8) can obtain:

[0030]

[0031] In the above formula, β is the elastic modulus deterioration coefficient defined by considering the weakening effect of the easily-argillized ore rock, and is obtained by calculating the test data, when β=0.41, the theoretical stress-strain curve is most consistent with the test stress-strain curve, therefore, formula (9) can be simplified as:

[0032]

[0033] According to formula (6), the initial damage of the easily-argillized ore rock in the compaction stage can be quantitatively calculated and analyzed, and according to formula (10), the theoretical stress-strain relationship of the easily-argillized ore rock in the initial compaction stage can be obtained.

[0034] Further, the size of the easily-argillized ore rock sample in step one is a standard cylindrical rock with a height of 100 mm and a diameter of 50 mm.

[0035] Further, the acoustic emission test in step two adopts a loading strain test, the loading rate is 0.005 mm / s, the loading is stopped when the sample is damaged, the sampling threshold value of the acoustic emission is 50 dB, the preamplifier gain is 45 dB, and the sampling rate is 3 MSPS.

[0036] Further, the calculation and analysis of the initial compaction stress and the acoustic emission parameter evolution characteristics of the easily-argillized ore rock under uniaxial compression in step three include that the ratio of the compaction stress to the peak stress of the crack closure is σ cc / σ f =0.37±0.02; and the acoustic emission parameter evolution of the easily-argillized ore rock under uniaxial compression can be divided into a compaction stage, an elastic stage, a crack stable expansion stage, a crack non-stable expansion stage and a post-peak stage.

[0037] The beneficial effects of the present application are:

[0038] The present application proposes a damage variable in the initial compaction stage based on the modified acoustic emission ringing count by calculating and analyzing the initial compaction stress of the easily-argillized ore rock combined with the evolution characteristics of the acoustic emission parameter, simulates the change rule of the initial damage of the easily-argillized ore rock in the compaction stage, can accurately calculate the damage degree of the easily-argillized ore rock, combines the damage variable in the initial compaction stage with the stress-strain relationship, establishes a constitutive model of the initial damage stage of the easily-argillized ore rock under uniaxial compression, and verifies the rationality and accuracy of the constitutive model by comparing with the test stress-strain curve; the analysis method of the present application can accurately and real-timely monitor the initial damage degree of the easily-argillized ore rock, and provides a scientific reference basis for quantifying the initial damage of the easily-argillized ore rock and monitoring the strength evolution rule in the mining process of the mine. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 Typical stress-strain relationship diagram of the easy-argillized rock specimen of the embodiment of the present application;

[0040] Figure 2a Stress-acoustic emission ring count-time relationship diagram of the easy-argillized rock specimen a of the embodiment of the present application;

[0041] Figure 2b Stress-acoustic emission event rate-time relationship diagram of the easy-argillized rock specimen a of the embodiment of the present application;

[0042] Figure 2c Stress-acoustic emission energy rate-time relationship diagram of the easy-argillized rock specimen a of the embodiment of the present application;

[0043] Figure 3a Stress-acoustic emission ring count-time relationship diagram of the easy-argillized rock specimen b of the embodiment of the present application;

[0044] Figure 3b Stress-acoustic emission event rate-time relationship diagram of the easy-argillized rock specimen b of the embodiment of the present application;

[0045] Figure 3c Stress-acoustic emission energy rate-time relationship diagram of the easy-argillized rock specimen b of the embodiment of the present application;

[0046] Figure 4a Stress-acoustic emission ring count-time relationship diagram of the easy-argillized rock specimen c of the embodiment of the present application;

[0047] Figure 4b Stress-acoustic emission event rate-time relationship diagram of the easy-argillized rock specimen c of the embodiment of the present application;

[0048] Figure 4c Stress-acoustic emission energy rate-time relationship diagram of the easy-argillized rock specimen c of the embodiment of the present application;

[0049] Figure 5a Stress-damage variable-strain relationship diagram of the initial compaction stage of the easy-argillized rock specimen a of the embodiment of the present application;

[0050] Figure 5b Stress-damage variable-strain relationship diagram of the initial compaction stage of the easy-argillized rock specimen b of the embodiment of the present application;

[0051] Figure 5c Stress-damage variable-strain relationship diagram of the initial compaction stage of the easy-argillized rock specimen c of the embodiment of the present application;

[0052] Figure 6aA test stress-theoretical stress-strain relationship diagram of the easy-argillization ore rock test piece a in an initial compaction stage of an embodiment of the present application;

[0053] Figure 6b A test stress-theoretical stress-strain relationship diagram of the easy-argillization ore rock test piece b in an initial compaction stage of an embodiment of the present application;

[0054] Figure 6c A test stress-theoretical stress-strain relationship diagram of the easy-argillization ore rock test piece c in an initial compaction stage of an embodiment of the present application; DETAILED DESCRIPTION

[0055] The easy-argillization ore rock initial damage quantification analysis method based on acoustic emission ringing count includes the following steps:

[0056] Step one, the ore rock test piece is made, and the ore rock test piece is an easy-argillization ore rock test piece;

[0057] The ore rock used in the embodiment is taken from a certain easy-argillization thick and large tantalum and niobium ore rock in Gannan, Jiangxi, and the fresh rock sample is taken from a depth of 200 m underground. After coring in January 2014, the rock sample placed in the natural environment on the ground is subjected to water absorption and weathering for 7 years, and a standard cylindrical test piece with a height of about 100 mm and a diameter of about 50 mm is made.

[0058] Step two, the acoustic emission test under the uniaxial compression condition is performed on the ore rock test piece in step one, and the axial displacement, load and acoustic emission parameter values of each ore rock test piece are obtained; the easy-argillization ore rock test pieces a, b and c with no obvious joints and fissures on the surface of the test pieces in step one are selected for the test, and the stress-acoustic emission ringing count-time relationship diagram, the stress-acoustic emission event rate-time relationship diagram and the stress-acoustic emission ringing count-time relationship diagram are drawn respectively.

[0059] As shown in Figure 2a , Figure 2b , Figure 2c , Figure 3a , Figure 3b , Figure 3c , Figure 4a , Figure 4b , Figure 4c , the acoustic emission parameters of the easy-argillization ore rock increase with the stress under the uniaxial compression, showing obvious stage characteristics, and the acoustic emission parameter values in different stages are quite different, indicating that the internal damage propagation characteristics of the easy-argillization ore rock test piece are different in different stress stages.

[0060] Step three, the initial compaction stress and the acoustic emission parameter evolution characteristics of the easy-argillization ore rock under uniaxial compression are calculated and analyzed;

[0061] The compaction stress is obtained by the crack volume strain method and numerical calculation in the elastic stage, and the relationship between the stress and the strain of the object under load is expressed as:

[0062]

[0063] Wherein: σ1, σ2 and σ3 are the principal stress in three directions, unit: MPa; ε1, ε2 and ε3 are the strain in the direction corresponding to the three principal stresses; E is the elastic modulus, unit: MPa; μ is the Poisson's ratio;

[0064] The present application adopts real strain ε v instead of virtual volume strain, so that the crack volume strain can be obtained.

[0065]

[0066] Further, the crack volume strain under uniaxial compression condition is:

[0067]

[0068] The crack initiation stress σ ci and damage stress σ cd can be obtained through formula (3). cc The closure stress σ ci needs to be further obtained through numerical calculation, so that the stress-strain relationship in the elastic stage can be approximately expressed by the following formula:

[0069] σ=Eε+a (4)

[0070] Wherein: σ is the axial stress, unit: MPa; ε is the axial strain; E is the elastic modulus in the real state, unit: MPa, and a is the intercept of the first order function on the σ axis; the value of a can be obtained by substituting the crack initiation stress σ ci and the corresponding strain ε cc into formula (4).

[0071] As shown in the figure, according to the volume strain and crack volume strain change characteristics of the argillization ore under uniaxial compression, combined with the numerical calculation of the first order function, the characteristic stresses of the argillization ore under uniaxial compression can be obtained. The characteristic stress analysis of the typical argillization ore sample is shown in Table 1. Figure 1

[0072] Table 1: Characteristic stresses of argillization ore sample at each stage

[0073]

[0074] ​From Table 1, the relationship between the same characteristic stress and peak stress of different argillized rock samples is close, and the ratio of each characteristic stress to peak stress is reasonable. The ratio of the compaction stress to peak stress is σ cc / σ f = 0.37 ± 0.02, the ratio of the cracking stress to peak stress is σ ci / σ f = 0.49 ± 0.01, and the ratio of the damage stress to peak stress is σ cd / σ f = 0.82 ± 0.04.

[0075] The activity of acoustic emission events is fully described by using the ring count, energy rate and event rate of acoustic emission. The ring count, energy rate and event rate of acoustic emission are used to analyze the acoustic emission parameters in different characteristic stresses. The ring count and energy rate of acoustic emission show obvious quiet period before the peak stress, and show weak fluctuation. The ring count and energy rate increase sharply near the peak stress, a large number of acoustic emission events occur in the sample, the cracks accelerate to expand and concentrate, and the sample loses bearing capacity and fails.

[0076] The acoustic emission parameter curve is divided into five stages according to the characteristic stress: compaction stage (OA section), elastic stage (AB section), crack stable expansion stage (BC section), crack stable expansion stage (BC section) and post-peak stage (DE section). Through the analysis of the acoustic emission parameter-time curve and stress-time curve of the argillized rock, it can be found that the acoustic emission parameter curve has a good corresponding relationship with the stress curve. Among them, the acoustic emission event rate-time curve has better effect in describing the characteristic stress.

[0077] Step four, define the damage variable of the argillized rock based on the modified acoustic emission ring count, and construct the damage constitutive model of the initial compaction stage of the argillized rock, the specific process is as follows:

[0078] Under the action of high water pressure and other geological conditions, the argillized rock often has a large amount of natural damage inside, which can cause significant deterioration of the elastic modulus of the argillized rock, increase the deformation under load and intensify the damage after the stress peak. Therefore, by quantifying the initial damage of the argillized rock in the natural state, the expression of the initial damage is constructed by using the acoustic emission parameters, which is crucial to study the influence of elastic modulus degradation on damage evolution.

[0079] The acoustic emission event rate and energy rate remain at a low level of stability in the initial compaction stage of loading (OA section in Figures 2, 3, 4), and it is difficult to accurately measure the difference between the initial compaction stage and other stages. Therefore, in order to more reasonably analyze the influence of initial damage on the deterioration of elastic modulus, the acoustic emission ring count is selected to quantitatively analyze the initial damage of the soft rock. The damage variable D of the rock sample at the end of the initial compaction stage is regarded as 0, that is, the initial damage is completely repaired in the compaction stage. Therefore, the initial damage is simply represented as:

[0080]

[0081] In the formula: D0 represents the initial damage when the strain of the sample is 0, σ cc , and σ f are the compaction stress and peak stress, respectively, with the unit of MPa, and the damage variable at the i-th moment in the compaction stage is:

[0082]

[0083] In the formula: D i represents the damage variable of the rock sample at the i-th moment in the compaction stage, R i is the cumulative acoustic emission ring count at the i-th moment in the compaction stage, R cc is the sum of the acoustic emission ring count in the compaction stage, and it can be seen that D i is a monotonically decreasing function greater than 0 in the compaction stage. According to the damage variable in the compaction stage, the equivalent elastic modulus E i % of the rock sample at the i-th moment in the compaction stage can be obtained as:

[0084]

[0085] In the formula: E is the true elastic modulus of the sample measured by the test, and based on the equivalent continuum mechanics, the stress and strain relationship in the compaction stage of the soft rock is discussed separately, and the constitutive model of the sample in the compaction stage can be further obtained through formula (7) as:

[0086]

[0087] In the formula: σ i represents the stress at the i-th moment in the compaction stage, and ε i is the strain at the i-th moment in the compaction stage. By substituting formula (5) into formula (8), the following formula can be obtained:

[0088]

[0089] In the formula, β is an elastic modulus deterioration coefficient defined by considering the weakening effect of the easily-argillized ore rock, and is obtained by calculating test data, when β=0.41, the theoretical stress-strain curve is most consistent with the test stress-strain curve, therefore, formula (9) can be simplified as:

[0090]

[0091] According to formula (6), the initial damage of the easily-argillized ore rock in the compaction stage is quantitatively calculated and analyzed, and according to formula (10), the theoretical stress-strain relationship of the easily-argillized ore rock in the initial compaction stage is obtained.

[0092] From Figure 5a , Figure 5b and Figure 5c , it can be seen that the initial damage variable value of the easily-argillized ore rock specimen is 0.37 when the strain is 0, with the increase of the strain, the initial damage is gradually compacted, the damage variable monotonically decreases and decreases to approach 0 at the end of the compaction stage. Therefore, it can be known that the damage variable established by the application can quantitatively describe the damage degree of the easily-argillized ore rock in the compaction stage, and the damage evolution characteristics of the easily-argillized ore rock in the initial compaction stage can be quantitatively analyzed by the damage variable.

[0093] From Figure 6a , Figure 6b , Figure 6c , it can be seen that the theoretical stress-strain curve obtained according to the compaction stage constitutive model is highly consistent with the test stress-strain curve, which shows that the stress-strain relationship of the easily-argillized ore rock in the initial compaction stage can be simulated by the constitutive model, and also shows that the deformation and failure of the easily-argillized ore rock can be regarded as a continuous progressive development process. At the same time, it further reflects that the quantification of the initial damage of the easily-argillized ore rock by the damage variable constructed in the paper is highly reasonable.

[0094] The application introduces acoustic emission ring count to establish the damage variable of the easily-argillized ore rock in the initial compaction stage under uniaxial compression condition, and constructs a constitutive model of the easily-argillized ore rock in the initial compaction stage based on acoustic emission ring count, so as to quantitatively analyze the initial damage of the easily-argillized ore rock, which can accurately and real-timely monitor the initial damage degree of the easily-argillized ore rock, and provides a scientific reference basis for quantifying the initial damage of the easily-argillized ore rock and monitoring the strength evolution law thereof in the mining process. The above disclosed is only the preferred embodiment of the application, and of course cannot limit the scope of rights of the application, therefore, the equivalent changes made according to the application scope still belong to the scope covered by the application.

Claims

1. A method for quantitative analysis of initial damage in easily mud-forming rocks based on acoustic emission ringing counting, characterized in that, Includes the following steps: Step 1: Prepare mineral and rock specimens, wherein the mineral and rock specimens are easily mud-forming mineral and rock specimens; Step 2: Conduct acoustic emission tests under uniaxial compression conditions on the mineral and rock specimens described in Step 1 to obtain the axial displacement, load, and acoustic emission parameter values ​​of each specimen. Step 3: Calculate and analyze the evolution characteristics of the initial compaction stress and acoustic emission parameters of the rock specimen under uniaxial compression; Step 4: Define the damage variable for easily mud-forming ore based on the modified acoustic emission ringing count, and construct a damage constitutive model for the initial compaction stage of easily mud-forming ore. The specific process is as follows: The relationship between stress and strain of an object under load is expressed by numerical calculation of compaction stress using the fracture volumetric strain method and the elastic stage, as follows: In the formula: σ1, σ2, and σ3 are the principal stresses in the three directions, with units of MPa; ε1, ε2, and ε3 are the strains in the directions corresponding to the three principal stresses; E is the elastic modulus, with units of MPa; μ is Poisson's ratio; Using real strain ε v Instead of virtual volumetric strain, the crack volumetric strain is obtained. for: The crack volumetric strain under uniaxial compression conditions is obtained as follows: The crack initiation stress σ is obtained through equation (3). ci and damage stress σ cd The closing stress σ cc Further numerical calculations are needed to obtain the stress-strain relationship in the elastic stage; therefore, the stress-strain relationship in the elastic stage is approximately expressed by the following formula: σ=Eε+a (4) In the formula: σ is the axial stress, in MPa; ε is the axial strain; E is the elastic modulus under the actual condition, in MPa; a is the intercept of the linear function on the σ axis; by using the crack initiation stress σ ci and the corresponding strain ε ci Substituting into equation (4), the value of a can be obtained. The stress at the first intersection of the linear function line of equation (4) and the stress-strain curve can be approximated as the compaction stress σ at crack closure. cc ; The initial damage of easily mud-forming ore was quantified using acoustic emission ringing count. The damage variable D of the ore specimen at the end of the initial compaction stage was considered to be 0, meaning that the initial damage was completely repaired during the compaction stage. Therefore, the initial damage was expressed as: In the formula: D0 represents the initial damage of the rock specimen when the strain is 0, σ cc σ f Here, represents the compaction stress and peak stress, respectively, in MPa. The damage variable at time i during the compaction stage is: In the formula: D i R represents the damage variable of the rock sample at time i during the compaction stage. i R is the cumulative acoustic emission ringing count at time i during the compaction stage. cc This is the sum of the acoustic emission ring counts during the compaction stage; it can be seen that D i During the compaction stage, the elastic modulus is a monotonically decreasing function greater than 0. Based on the damage variable during the compaction stage, the equivalent elastic modulus E of the rock sample at time i in this stage is obtained. i %for: In the formula: E is the true elastic modulus of the specimen measured in the experiment. Based on the equivalent continuum mechanics, the stress-strain relationship of the easily mud-forming ore rock in the compaction stage is discussed separately. The constitutive model of the specimen in the compaction stage can be further obtained through formula (7): In the formula: σ i ε represents the stress at time i during the compaction stage. i For the strain at time i during the compaction stage, substituting equation (5) into equation (8) yields: In the above formula, β is the elastic modulus degradation coefficient defined considering the weakening effect of easily mud-forming rocks. It is obtained by calculation based on experimental data. When β = 0.41, the theoretical stress-strain curve and the experimental stress-strain curve are in best agreement. Therefore, formula (9) is simplified to: The damage variables at time i in the quantitative analysis of the initial damage of easily mud-forming ore rock are obtained from equation (6), and the theoretical stress-strain relationship of the initial damage of easily mud-forming ore rock is obtained from equation (10).

2. The method for quantitative analysis of initial damage in easily mud-forming ore rocks based on acoustic emission ringing counting according to claim 1, characterized in that, The easily mud-forming rock specimen mentioned in step one is a standard cylindrical rock with a height of 100 mm and a diameter of 50 mm.

3. The method for quantitative analysis of initial damage in easily mud-forming ore rocks based on acoustic emission ringing counting according to claim 1, characterized in that, The acoustic emission test described in step two adopts a loading strain test with a loading rate of 0.005 mm / s. Loading is stopped when the specimen fails. The acoustic emission sampling threshold is 50 dB, the preamplifier gain is 45 dB, and the sampling rate is 3 MSPS.

4. The method for quantitative analysis of initial damage in easily mud-forming ore rocks based on acoustic emission ringing counting according to claim 1, characterized in that, Step three involves calculating and analyzing the evolution characteristics of the initial compaction stress and acoustic emission parameters of easily mud-forming ore rocks under uniaxial compression, including: the ratio of the compaction stress at fracture closure to the peak stress is σ. cc / σ f =0.37±0.02; The evolution of acoustic emission parameters under uniaxial compression of easily mud-forming rocks is divided into the compaction stage, elastic stage, stable crack propagation stage, unstable crack propagation stage, and post-peak stage.

Images