Crack classification method for quantifying disturbance catastrophe in fault zone tunnels using acoustic emission events

Abstract

The present invention discloses a crack classification method for quantifying disturbance catastrophes in fault zone tunnels by using acoustic emission events, and relates to the field of mine safety technology. The specific steps are as follows: obtaining sample structure parameters and preparing consistent similar materials of fault zones; preparing cylindrical specimens, and setting filling similar materials of fault zones in the cylindrical specimens to obtain fault zone-tunnel composite structure specimens; carrying out blasting seismic wave monitoring in fault zone tunnels and reducing them in proportion to obtain experimental blasting seismic wave data; arranging deformation sensors and acoustic emission probes on the fault zone-tunnel composite structure specimens, carrying out fatigue-creep-unloading confining pressure interactive mechanical tests, and using Kneedle algorithm to solve the critical slope of acoustic emission discrete data, and determining the crack type according to the critical slope and the dividing line equation. The above-mentioned crack classification method for quantifying disturbance catastrophes in fault zone tunnels by using acoustic emission events improves the accuracy of crack classification and more objectively reveals the rupture morphology.

Description

Technical Field

[0001] The invention relates to the field of mine safety technology, and in particular to a crack classification method for quantifying disturbance catastrophes in fault zone tunnels by using acoustic emission events. Background Art

[0002] With the gradual increase in the mining depth of metal mines, the development of deep shafts and tunnels and the mining process will encounter fault fracture zones and complex disturbance stress environments, which will make the deep mining projects of mines face more and more risks and challenges. The occurrence of many mine shafts, tunnels and mining disasters is closely related to fault fracture zones. Compared with the intact rock mass, the surrounding rock of the fault fracture zone is usually composed of debris such as fault mud and fault breccia. The mismatch of its internal structure in strength and stiffness makes the rock mass in the fracture zone more susceptible to mechanical degradation under complex stress conditions. In the study of indoor experiments, since the geometric shape of the hollow cylindrical rock specimen is close to the in-situ conditions of tunnels, shafts and boreholes in the project, it can simulate the excavation of shafts and tunnels and consider the influence of axial pressure. Therefore, many scholars have used hollow cylinders to simulate the overall structure of shafts and tunnels and surrounding rocks. It is believed that the failure characteristics of hollow cylinders under external forces can reflect the instability characteristics of shafts and tunnels and surrounding rocks under the action of ground stress. With the deepening of research, some scholars have considered the influence of primary and prefabricated cracks in recent years, and considered the influence of structural surfaces on the deformation and destruction process of the structure by presetting joints and cracks in hollow cylinders. However, strictly speaking, in the field of rock mechanics, fault fracture zones no longer belong to the category of structural surfaces, but to a special geological body called weak interlayers, in which the structural fracture zone is composed of debris such as fault mud and fault breccia, which is a typical broken interlayer and has essential properties different from the previous joints and cracks. The occurrence form of fault fracture zones in engineering usually forms a combined structure with shafts, tunnels and surrounding rocks. Therefore, how to prepare an artificial fault fracture zone-shaft structure combined structure similar to the engineering rock mass is crucial to studying the instability process and mechanical mechanism of fault zone tunnels.

[0003] At present, scholars only consider the mechanical response and failure characteristics of rocks under a single constant load (creep) or cyclic load (fatigue), and have achieved a lot of research results. In fact, from the perspective of long-term stability of rock mass, the loads borne by rock mass in many actual projects during service are usually not single. Especially for deep rock mass engineering, the cyclic blasting or mechanical rock drilling disturbances borne by the surrounding rock of the fault fracture zone tunnel usually have a certain time interval. During the interval of fatigue disturbance, the rock mass may also undergo creep deformation under the action of additional stresses such as high ground stress or stress adjustment, which has an irreversible effect on the fatigue characteristics of the rock mass. At the same time, with the development of the project, the hydrostatic stress environment of the surrounding rock is not constant, but in an unloading state. For this reason, it is particularly important to study the mechanical response of the surrounding rock of the fault fracture zone under the interaction of fatigue disturbance-age creep-confining pressure unloading and the identification of instability precursor information.

[0004] The evolution process of instability in fault zone tunnels in deep mines involves the activation of strongly cemented soil-rock mixtures in the fault zone and the deformation and destruction of surrounding rocks. The macroscopic instability and destruction is the result of the aggregation, nucleation, interconnection and interaction of microcracks in the soil-rock mixture with the surrounding rock fracture. Microcracks not only dominate the fracture process of fault activation at different loading stages, but also reflect the fracture rules and types. Exploring and revealing the characteristics of crack types and failure modes is helpful to understand the causal mechanism of fault zone tunnel engineering disasters, which is very important for mastering the mechanical mechanism of rock mass disasters and maintaining the stability and safety of shaft and tunnel engineering, especially in the analysis of rock mass engineering damage mechanism and disaster risk assessment. Acoustic emission monitoring is an effective and widely used non-destructive monitoring method used in the monitoring of rock mass instability disasters. Among them, a lot of work has been carried out on the identification of precursor information of rock mass fracture process based on acoustic emission parameter method, especially on the quantitative identification of tensile and shear failure mechanisms and tensile and shear cracks. The quantitative description of tensile and shear cracks is determined by using the scatter plot of the two parameters AF (average frequency) and RA (rise time / amplitude) to determine the density division area, and the boundary equation is used to distinguish tensile and shear cracks. However, the RA-AF method has uncertainty and strong subjectivity, and the boundary equations determined by different scholars are very different. However, RA and AF are widely used in the classification of rock mass rupture modes. Therefore, scientifically and reasonably determining the boundary equation of tensile and shear cracks has a very great research significance for the analysis of rupture mechanisms and early warning of engineering rock mass instability. Summary of the invention

[0005] The purpose of the present invention is to provide a crack classification method for quantifying disturbance disasters in fault zone tunnels using acoustic emission events. Starting from indoor mechanical experiments, the tensile and shear cracks are quantitatively classified and evaluated by simulating the activation of the fault fracture zone and inducing the evolution of tunnel disasters, providing technical support for disaster control.

[0006] To achieve the above object, the present invention provides a crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events, and the specific steps are as follows:

[0007] Step S1: obtaining the uniaxial compressive strength of the sample structure of the original fault fracture zone in the middle section of the deep stope through a point load test;

[0008] Step S2: obtaining the internal structure and components of the sample structure, and preparing a fault zone-similar material having the same internal structure, components and uniaxial compressive strength as the sample structure;

[0009] Step S3: obtaining rock samples in the fault zone tunnel and making them into cylindrical samples, setting cracks with set widths and set inclination angles in the cylindrical samples, and filling the cracks with materials similar to the fault zone to obtain a fault zone-tunnel composite structure sample;

[0010] Step S4: monitoring blasting seismic waves in the fault zone tunnel, obtaining a waveform file of the blasting seismic waves, obtaining a main frequency and a main amplitude according to Fourier transform, and reducing the main frequency and the main amplitude in proportion to obtain test blasting seismic wave data;

[0011] Step S5: Arrange deformation sensors and acoustic emission probes on the fault zone-tunnel composite structure sample to collect rupture time and crack location; arrange the deformation sensors in the axial and radial directions, and provide a plurality of acoustic emission probes.

[0012] Step S6: performing a fatigue-creep-unloading confining pressure interactive mechanical test, and using acoustic emission monitoring to record rupture events during the test;

[0013] Step S7: using the Kneedle algorithm to solve the critical slope of the acoustic emission discrete data, and determining the crack type according to the critical slope and the dividing line equation.

[0014] Preferably, in step S1, the number of sample structures in the same group in the test should be about 5-10. Since the sample structures are random and the results are discrete, irregular fault zone blocks are used in this test, and the number is set to 15-20. For invalid data appearing in the test, they are eliminated and the average value of the remaining data is calculated.

[0015] Step S1 is specifically as follows:

[0016] Step S11: Calculate the equivalent diameter of the irregular original fault zone sample, and the calculation formula is as follows:

[0017] ;

[0018] in, is the equivalent core diameter of the irregular undisturbed fault zone sample, D is the spacing between loading points, and b is the width of the minimum cross section passing through two loading points;

[0019] Step S12: Calculate the initial point load strength index, the calculation formula is as follows:

[0020] ;

[0021] in, is the uncorrected point load strength index (unit: MPa), P is the failure load (unit: N);

[0022] Step S13: When the loading point spacing D is not 50 mm, the calculated value is corrected to calculate the correction point load strength index. The calculation formula is as follows:

[0023] (1) When fault zone samples are easily available and DE in the same group of samples has different sizes other than 50 mm, plot DE according to the test results. 2 -P relationship curve. According to the curve, DE2=2500mm 2 The corresponding P50 is calculated as follows:

[0024] ;

[0025] Among them, P50 is the corrected failure load, is the modified point load strength index;

[0026] (2) When samples of deep hidden fault zones are difficult to obtain, calculate the rock point load strength index:

[0027]

[0028] ;

[0029] Among them, F is the size correction factor; for the same type of rock, the empirical value of m is 0.45;

[0030] Step S14: Calculate the uniaxial compressive strength using the following formula:

[0031] ;

[0032] Among them, B is a fixed coefficient, which is 24 for fault zone rocks.

[0033] Preferably, in step S2, CT scanning, screening samples and XRD tests are used to obtain the internal structure, particle size distribution and mineral composition.

[0034] Preferably, in step S3, tunnel holes are prefabricated in the cylindrical sample, the tunnel holes are smaller than 1 / 3 of the diameter of the cylindrical sample, and the cylindrical sample with the tunnel holes is divided into three parts of rock blocks by using a set angle and width line cutting method. After the middle rock block is taken out, a crack is obtained, and the crack is filled with a material similar to the fault zone.

[0035] The following principles should be followed when preparing the fault zone-mine composite structure specimen:

[0036] Take a cylindrical specimen with a diameter of 100 mm and a height of 200 mm as an example.

[0037] a. In order to minimize the stress effect on the sample boundary, according to Saint-Venant's principle, the hole diameter should be less than 1 / 3 of the sample diameter, and the hole diameter is set to 30 mm. According to the similarity in scale between the tunnel width and the structural fracture zone, the fault zone width is set to 4 mm, 6 mm, 9 mm and 12 mm.

[0038] b. For the breccia and fault mud in the fault fracture zone taken on site, the soil and rock threshold is 0.05-0.07Lc (Lc is the engineering characteristic scale, that is, the thickness of the fault zone). Considering the actual sieving aperture size, gravel with a particle size of 1-3mm was selected as fault breccia during sample preparation, and particles with a particle size of <0.075mm were selected as fault mud. They were filled into the prefabricated cracks at a mass fraction of 35% and 65%. Metal bars were used to tamp and compact during the filling process to ensure that the prefabricated cracks were completely filled. The dry density of the filling was controlled to be 2.0g / cm 3 The moisture content is controlled at 10% based on the actual measured value of on-site sampling.

[0039] Preferably, step S7 is specifically as follows:

[0040] Step S71: normalization processing of acoustic emission discrete data;

[0041] The specific processing process is as follows:

[0042] The acoustic emission discrete data is: ;

[0043] in, is the acoustic emission discrete data, For the The ratio of the acoustic emission parameters AF (average frequency) to RA (rise time / amplitude) in the acoustic emission data. For the The proportion of shear cracks in the acoustic emission data, R is the set of all points on the plane xoy;

[0044] The normalization formula is as follows:

[0045] ;

[0046] in, is the normalized acoustic emission discrete data, Normalized , Normalized , For all A collection of For all A collection of;

[0047] Step S72: Calculate difference data;

[0048] The difference data set calculation formula is as follows:

[0049] ;

[0050] in, For normalized data and The difference data set, and The values ​​of are the same, for and The difference between

[0051] Step S73: Calculate the local maximum value of the difference data set;

[0052] The calculation formula is as follows:

[0053] ;

[0054] in, is the set of local maxima, and The values ​​of are the same, is the local maximum in the interpolated data set;

[0055] Step S74: setting a threshold to limit the selection range of local data in the local maximum value;

[0056] The threshold calculation formula is as follows:

[0057] ;

[0058] in, is the threshold value, is the sensitivity parameter; n is the number of data points;

[0059] Step S75: knee point detection;

[0060] For any local maximum , before reaching the next local maximum , where j>i, when Below threshold , then this local maximum A knee point is detected at The corresponding ratio of acoustic emission AF (average frequency) to RA (rise time / amplitude) is the critical slope ;

[0061] Step S76: determining the crack type according to the critical slope and the dividing line equation;

[0062] The dividing line equation is as follows:

[0063]

[0064] Among them, AF is the average frequency of the acoustic emission signal, RA is the ratio of the rise time of the acoustic emission signal to the maximum amplitude, and the RA-AF correlation and crack classification result diagram are obtained from the above formula.

[0065] Therefore, the present invention adopts the above-mentioned crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events, which has the following beneficial effects:

[0066] (1) The structural characteristics and strength properties of the original fault zone soil-rock mixture were taken into consideration. The fault zone-shaft composite structure specimens were prepared according to the strength matching criterion and the structural similarity principle. Through cracks of different widths and angles were pre-set in the hollow cylinder test to simulate the fault zone, and the artificial fault zone samples were filled in the cracks.

[0067] (2) By combining acoustic emission real-time monitoring and positioning with fatigue-creep-unloading surrounding rock interactive mechanical tests, the evolution characteristics of the entire process of fault zone activation and tunnel instability are revealed. The fatigue disturbance frequency and amplitude are equivalently reduced according to the stress wave characteristics of the mine blasting vibration record, the creep is considered to be prolonged during the engineering disturbance interval, and the confining pressure unloading is considered to be different excavation rates, which is more in line with the actual situation and improves the classification accuracy.

[0068] (3) The knee point of discrete acoustic emission data is calculated using the kneele algorithm to determine the critical slope and dividing line method for crack classification, revealing the proportion of tensile cracks and shear cracks in different loading stages and predicting the critical stress state of instability of the composite structure. This overcomes the problems of uncertainty, strong subjectivity, and differences in the determined dividing equations of the RA-AF method.

[0069] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1A flow chart of a crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events according to the present invention;

[0071] Figure 2 This is a schematic diagram of deep mine tunnel excavation through a fault fracture zone;

[0072] Figure 3 This is a simplified schematic diagram of deep mine tunneling through a fault fracture zone;

[0073] Figure 4 It is a perspective view of a fault zone-well and tunnel composite structure sample of the present invention;

[0074] Figure 5 It is a front view of a fault zone-well and tunnel composite structure sample of the present invention;

[0075] Figure 6 It is a side view of a fault zone-well and tunnel composite structure sample of the present invention;

[0076] Figure 7 It is a schematic diagram of the loading path of the fatigue-creep-unloading confining pressure interactive mechanical test of the present invention;

[0077] Figure 8 This is a diagram showing the critical slope test result of a fault zone-well and tunnel composite structure sample with a crack having an inclination angle of 5° according to the present invention;

[0078] Fig. 9 This is a crack classification result diagram of a fault zone-well and tunnel composite structure specimen with a crack with an inclination angle of 5° according to the present invention;

[0079] Fig.10 This is a diagram showing the critical slope test results of a fault zone-well and tunnel composite structure sample with a crack having an inclination angle of 25° according to the present invention;

[0080] Fig.11 This is a crack classification result diagram of a fault zone-well and tunnel composite structure specimen with a crack inclination angle of 25° according to the present invention.

[0081] Reference numerals

[0082] 1. Tunnel; 2. Surrounding rock; 3. Fault fracture zone; 4. Blasting load; 5. Blasting seismometer; 6. Disturbance stress wave; 7. Tunnel holes; 8. Confining pressure; 9. Cylindrical specimen; 10. Weak interlayer in fault zone. DETAILED DESCRIPTION

[0083] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the invented product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0084] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0085] Example

[0086] This example takes the fault zone-tunnel composite structure sample in the deep part of Sanshandao gold mine as an example. Figure 2 and Figure 3 As shown, a fault fracture zone 3 is provided in the surrounding rock 2 , and the tunnel 1 passes through the fault fracture zone 3 .

[0087] like Figure 1 As shown in FIG. 1 , a crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events is described. The specific steps are as follows:

[0088] Step S1: obtaining the uniaxial compressive strength of the sample structure in the original fault fracture zone in the middle section of the deep stope through a point load test.

[0089] Step S2: Obtain the internal structure and components of the sample structure, and prepare a fault zone-similar material that is consistent with the internal structure, components and uniaxial compressive strength of the sample structure.

[0090] Step S3: Obtain rock samples in the fault zone tunnel and make them into cylindrical samples 9, such as Figure 4-Figure 6 As shown, cracks and tunnel holes 7 with set widths and set inclination angles are set in the cylindrical sample 9, and fault zone-similar materials are filled in the cracks to obtain a fault zone-well and tunnel composite structure sample.

[0091] Step S4: a blasting seismometer 5 is set in the tunnel to monitor the blasting seismic wave generated by the blasting load 4, and the waveform file of the blasting seismic wave is obtained. The main frequency and main amplitude are obtained according to Fourier transform, and the main frequency and main amplitude are proportionally reduced to obtain the test blasting seismic wave data.

[0092] Step S5: Arrange deformation sensors and acoustic emission probes on the fault zone-tunnel composite structure sample to collect rupture time and crack location; arrange the deformation sensors in the axial and radial directions, and set 8 acoustic emission probes.

[0093] Step S6: Conduct fatigue-creep-unloading confining pressure interactive mechanical test. During the test, acoustic emission monitoring is used to record rupture events. The perturbation stress wave 6 and confining pressure 8 loading process are as follows: Figure 7 shown.

[0094] Step S7: using the Kneedle algorithm to solve the critical slope of the acoustic emission discrete data, and determining the crack type according to the critical slope and the dividing line equation.

[0095] In the fault zone-tunnel composite structure specimen, cracks with inclination angles of 5° and 25 (crack width 4 mm) were set to fill the fault zone with similar materials to obtain a fault zone-tunnel composite structure specimen with a weak interlayer 10 in the fault zone. Fatigue-creep-unloading confining pressure interactive mechanical tests were carried out indoors. During the test, acoustic emission monitoring technology was used to record the rupture events during the loading process. Set the sensitivity parameter S=2, such as Figure 8 and Fig.10 As shown, for the inclination The critical slope of the crack classification for the weak interlayer 10 of the fault zone with an angle of 5° and 25° is They are 5.33 and 4.81 respectively.

[0096] For the fault zone-tunnel composite structure sample with a fault zone weak interlayer 10 with a dip angle of 5°, the critical slope The tensile and shear cracks of the specimens were distinguished by using the boundary equation AF=5.33RA. The RA-AF correlation and crack classification results were obtained as follows: Fig. 9 For the specimen with β of 5°, the crack classification results show that shear cracks account for 88.6% and tensile cracks account for 11.4%, respectively, and the specimen is mainly shear failure.

[0097] For the fault zone-tunnel composite structure sample with a fault zone weak interlayer 10 with a dip angle of 25°, the critical slope The tensile and shear cracks of the specimens are distinguished by the value of 4.81. The dividing line equation is AF=4.81RA. The RA-AF correlation and crack classification results are as follows: Fig.11As shown in the figure, the crack classification results show that shear cracks account for 94.5% and tensile cracks account for 5.5%. Compared with the fault zone-tunnel composite structure specimen with a fault zone weak interlayer 10 with a dip angle of 5°, the fault zone-tunnel composite structure specimen with a fault zone weak interlayer 10 with a dip angle of 25° has an increased number of shear cracks, and shear failure is still the main type, mainly shear slip type failure along the fault zone.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events, characterized in that: The specific steps are as follows: Step S1: obtaining the uniaxial compressive strength of the sample structure of the original fault fracture zone in the middle section of the deep stope through a point load test; Step S2: obtaining the internal structure and components of the sample structure, and preparing a fault zone-similar material having the same internal structure, components and uniaxial compressive strength as the sample structure; Step S3: obtaining rock samples in the fault zone tunnel and making them into cylindrical samples, setting cracks with set widths and set inclination angles in the cylindrical samples, and filling the cracks with materials similar to the fault zone to obtain a fault zone-tunnel composite structure sample; Step S4: monitoring blasting seismic waves in the fault zone tunnel, obtaining a waveform file of the blasting seismic waves, obtaining a main frequency and a main amplitude according to Fourier transform, and proportionally reducing the main frequency and the main amplitude to obtain test blasting seismic wave data; Step S5: Arranging deformation sensors and acoustic emission probes on the fault zone-tunnel composite structure sample to collect rupture time and crack location; Step S6: performing a fatigue-creep-unloading confining pressure interactive mechanical test, and using acoustic emission monitoring to record rupture events during the test; Step S7: using Kneedle algorithm to solve the critical slope of the acoustic emission discrete data, and determining the crack type according to the critical slope and the dividing line equation; Step S7 is specifically as follows: Step S71: normalization processing of acoustic emission discrete data; The specific processing process is as follows: The acoustic emission discrete data is: ; in, is the acoustic emission discrete data, For the The ratio of acoustic emission parameters AF to RA in acoustic emission data, For the The proportion of shear cracks in the acoustic emission data, R is the set of all points on the plane xoy; The normalization formula is as follows: ； in, is the normalized acoustic emission discrete data, Normalized , Normalized , For all A collection of For all A collection of; Step S72: Calculate difference data; The difference data set calculation formula is as follows: ； in, For normalized data and The difference data set, and The values ​​of are the same, for and The difference between Step S73: Calculate the local maximum value of the difference data set; The calculation formula is as follows: ； in, is the set of local maxima, and The values ​​of are the same, is the local maximum in the interpolated data set; Step S74: setting a threshold to limit the selection range of local data in the local maximum value; The threshold calculation formula is as follows: ； in, is the threshold value, is the sensitivity parameter; n is the number of data points; Step S75: knee point detection; For any local maximum , before reaching the next local maximum , where j>i, when Below threshold , then this local maximum A knee point is detected at The corresponding ratio of acoustic emission AF to RA is the critical slope ; Step S76: determining the crack type according to the critical slope and the dividing line equation; The dividing line equation is as follows: Among them, AF is the average frequency of the acoustic emission signal, RA is the ratio of the rise time of the acoustic emission signal to the maximum amplitude, and the RA-AF correlation and crack classification result diagram are obtained from the above formula.

2. A crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events according to claim 1, characterized in that: Step S1 is specifically as follows: Step S11: Calculate the equivalent diameter of the irregular original fault zone sample, and the calculation formula is as follows: ； in, is the equivalent core diameter of the irregular undisturbed fault zone sample, D is the distance between loading points, and b is the width of the minimum cross section passing through two loading points; Step S12: Calculate the initial point load strength index, the calculation formula is as follows: ； in, is the uncorrected point load strength index, P is the failure load; Step S13: Correction of the initial point load strength index; when the loading point spacing D is not 50 mm, the calculated value is corrected to calculate the correction point load strength index; Step S14: Calculate the uniaxial compressive strength using the following formula: ； Among them, B is a fixed coefficient, which is 24 for fault zone rocks.

3. A crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events according to claim 2, characterized in that: The correction method of the initial point load strength index is as follows: According to the test results, draw DE 2 -P relationship curve, according to which DE can be found 2 =2500mm 2 The corresponding P50 is used to calculate the load intensity index of the correction point: ； Among them, P50 is the corrected failure load, is the modified point load strength index.

4. A crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events according to claim 2, characterized in that: Calculate the modified point load intensity index: ； Among them, F is the size correction coefficient; for the same type of rock, the empirical value of m is 0.

45.

5. A crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events according to claim 3 or 4, characterized in that: In step S2, CT scanning, sieve samples and XRD tests are used to obtain the internal structure, particle size distribution and mineral composition.

6. A crack classification method for quantifying disturbance catastrophes in fault zone tunnels using acoustic emission events according to claim 5, characterized in that: In step S3, tunnel holes are prefabricated in the cylindrical sample, and the tunnel holes are smaller than 1 / 3 of the diameter of the cylindrical sample. The cylindrical sample with the tunnel holes is divided into three rock blocks by using a set angle and width line cutting method. After taking out the middle rock block, a fracture zone is obtained, and the fracture zone is filled with materials similar to the fault zone.

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