A comprehensive evaluation method for rock burst tendency

Abstract

The application provides a rockburst tendency comprehensive evaluation method, and effectively solves problems such as non-uniformity of a benchmark, unreasonable processing of evidence conflicts and the like in existing rockburst evaluation methods through scientific dimensionless processing and DS evidence fusion theory, and provides more accurate and reliable data support for rockburst risk evaluation.

Description

Technical Field

[0001] This application relates to the field of geology, specifically to a comprehensive evaluation method for rockburst tendency. Background Technology

[0002] Rockburst is a common disaster in underground engineering. Its occurrence mechanism is complex and involves the interaction of multiple factors.

[0003] Currently, the main shortcomings of rockburst tendency evaluation methods are as follows: 1. Most methods do not perform dimensionless processing on indicators with different dimensions, resulting in a lack of comparability between indicators.

[0004] 2. The determination of weights lacks physical basis and often relies on mathematical correlation or expert subjective judgment, such as CRITIC, PCA, AHP and other methods, which are difficult for field engineers to verify.

[0005] 3. When different indicators conflict, existing methods fail to effectively handle conflicting evidence, which can easily lead to misjudgment. Summary of the Invention

[0006] This application provides a comprehensive evaluation method for rockburst tendency. Through scientific dimensionless processing and DS evidence fusion theory, it effectively solves the problems of inconsistent benchmarks and unreasonable handling of evidence conflicts in existing rockburst assessment methods, and provides more accurate and reliable data support for rockburst risk assessment.

[0007] This application provides a comprehensive evaluation method for rockburst tendency, the method comprising: The initial values ​​of four physical indices were obtained from multiple measuring points in the soil and rock area to be evaluated at the same time. The four physical indices include energy, stiffness, integrity and geostress. The initial index values ​​are normalized to obtain the corresponding normalized values; For each physical index and each measuring point, the appropriate rockburst level is determined based on the corresponding normalized value, and the corresponding membership function value is calculated through the membership function adapted to the appropriate rockburst level. For each physical index, under the condition of following the Dempster-Shafer evidence theory, a basic probability assignment is constructed based on the membership function value to obtain the basic probability value corresponding to each rockburst level; For each pair of physical indicators, the corresponding conflict coefficient is calculated by combining the basic probability value corresponding to the basic probability allocation. Based on the conflict coefficients of the pairs of physical indicators, the corresponding basic probability assignments are fused using the Dempster rule to obtain the corresponding comprehensive confidence levels of the pairs of physical indicators. The combined confidence scores of the paired physical indicators are integrated into a single composite index through a weighted summation, where the weights are allocated based on the importance of each indicator to rockburst prediction. The target rockburst tendency level for the soil and rock area to be evaluated under the current conditions is determined based on the comprehensive index and then output.

[0008] As an exemplary embodiment, the initial index values ​​of four physical indicators measured simultaneously at multiple measuring points in the soil and rock area to be evaluated are obtained, including: For the soil and rock area to be evaluated, uniaxial compression tests are carried out. Based on the complete stress-strain curves obtained from the uniaxial compression tests, the total input energy density before the peak and the failure energy density after the peak are obtained. The ratio of the total input energy density before the peak to the failure energy density after the peak is calculated as the initial index value of the energy index. For the soil and rock region to be evaluated, the elastic modulus before the peak value is determined based on the slope of the linear portion of the stress-strain curve before the peak value, and the post-peak reduction modulus is determined based on the slope of the stress-strain curve after the peak value. The ratio of the elastic modulus before the peak value to the post-peak reduction modulus is calculated as the initial index value of the stiffness index. For the soil and rock area to be evaluated, the square of the ratio of the elastic longitudinal wave velocity of the rock mass to the elastic longitudinal wave velocity of the rock is used as the initial index value of the integrity index. For the soil and rock area to be evaluated, the ratio of the uniaxial compressive strength of the rock to the maximum principal stress is used as the initial index value of the geostress index.

[0009] As another exemplary embodiment, the normalization process includes the following processing: A CFnorm =A CF / 5, where A CFnorm A is the normalized value corresponding to the energy index. CF Energy index; DMI norm =1.0 / DMI, where DMI norm The normalized value is the corresponding stiffness index, DMI is the stiffness index; Kv norm =Kv / 0.75, where Kv norm Kv is the normalized value corresponding to the completeness index; T Znorm =2.5 / TZ, where T Znorm T is the normalized value corresponding to the geostress index. Z This is an index of ground stress.

[0010] As another exemplary embodiment, the rockburst level adaptation strategy includes the following: For energy indicators, corresponding to the no-rockburst level, A CFnorm <0.4; corresponds to a weak rockburst level, 0.4≤A CFnorm <0.6; corresponding to medium rockburst level, 0.6≤A CFnorm <1.0; corresponds to a strong rockburst level, A CFnorm ≥1.0; For stiffness indices, corresponding to the no-rockburst rating, DMI norm <1.0; corresponding to medium rockburst level, DMI norm ≥1.0; For the integrity index, corresponding to the no-rockburst level, Kv norm <0.4667; corresponds to a weak rockburst level, 0.4667≤Kv norm <0.7333; corresponds to a medium rockburst level, 0.7333≤Kv norm <1.0; corresponds to a strong rockburst level, Kv norm ≥1.0; For the in-situ stress index, corresponding to the no-rockburst level, T Znorm <0.172; corresponds to a weak rockburst level, 0.172≤T Znorm ≤0.4545; corresponding to medium rockburst level, T Znorm <1.0; corresponds to a strong rockburst level, T Znorm ≥1.0; Membership function adaptation strategies include the following: For energy indices, corresponding to the no-rockburst level, when x < 0.4, μ ACF (x)=1, μ Q (x) is the membership function quantification value of the Q index under the normalized value x of the input index; corresponding to the weak rockburst level, when 0.4 ≤ x < 0.6, μ ACF (x) = (x - 0.4) / 0.2; corresponding to medium rockburst level, when 0.6 ≤ x < 1.0, μ ACF (x) = (x - 0.6) / 0.4; corresponding to a strong rockburst level, when x ≥ 1.0, μ ACF (x)=1; For the stiffness index, corresponding to the rockburst-free rating, μ DMI (x)=1, when x<1.0; corresponding to a weak rockburst level, when 1.0≤x<1.5, μ DMI (x) = (x - 1.0) / 0.5; corresponding to medium rockburst level, when 1.5 ≤ x < 2.0, μ DMI (x) = (x - 1.5) / 0.5; corresponding to a strong rockburst level, when x ≥ 2.0, μ DMI (x)=1; For the integrity index, corresponding to the no-rockburst level, when x < 0.4667, μ Kv(x)=1; corresponding to a weak rockburst level, when 0.4667≤x<0.7333, μ Kv (x) = (x - 0.4667) / 0.2666; corresponding to medium rockburst level, when 0.7333 ≤ x < 1.0, μ Kv ((x) = (x - 0.7333) / 0.2667; corresponding to a strong rockburst level, when x ≥ 1.0, μ Kv (x)=1; For the in-situ stress index, corresponding to the no-rockburst level, when x < 0.172, μ TZ (x)=1; corresponding to a weak rockburst level, when 0.172≤x<0.4545, μ TZ (x) = (x - 0.172) / 0.2825; corresponding to medium rockburst level, when 0.4545 ≤ x < 1.0, μ TZ (x) = (x - 0.4545) / 0.5455; corresponding to a strong rockburst level, when x ≥ 1.0, μ TZ (x)=1.

[0011] As yet another exemplary embodiment, the basic probability allocation follows the following formula: , in, Let i be the probability value assigned to the current indicator at level i, where i = 1, 2, 3, 4, corresponding to no rockburst level, weak rockburst level, medium rockburst level, and strong rockburst level, respectively. This represents the membership function value of the current indicator at level i. This is the sum of the membership function values ​​for all levels of the current indicator.

[0012] As another exemplary embodiment, the conflict coefficient is calculated using the following formula: , Where K is the conflict coefficient. Let A be the probability value obtained by assigning the set of rockburst levels A supported by the i-th indicator in the paired indicators to the basic probability distribution. Let A be the probability value obtained by assigning the set of rockburst grades B supported by the j-th indicator in the pairwise indicators to the basic probability distribution. A∩B=Ø indicates that the two sets of rockburst grades have no intersection.

[0013] As another exemplary embodiment, the overall confidence level for each pair of physical indicators is calculated using the following formula: , in, Let X be the overall confidence level of the input X. The input X is the intersection of the rockburst level set A and the rockburst level set B. A∩B=X means that the intersection of the rockburst level sets supported by the two indicators is X.

[0014] As another exemplary embodiment, the composite index is calculated by the following formula: , wherein, IBI is the composite index, n is the total number of index pairs, is the index pair weight of the i-th index pair, is the composite confidence of grade j corresponding to the i-th index pair, is the grade weight of grade j.

[0015] As another exemplary embodiment, the corresponding relationship between different composite indexes and different rockburst tendency grades is specifically as follows: IBI≤1.0: no rockburst tendency; 1.0<IBI<2.0: weak rockburst tendency; 2.0<IBI<3.0: moderate rockburst tendency; IBI≥3.0: strong rockburst tendency.

[0016] It can be concluded from the above content that the present application has the following beneficial effects: Aiming at the comprehensive evaluation target of rockburst tendency, through scientific dimensionless processing and DS evidence fusion theory, the present application effectively solves the problems of inconsistent benchmarks and unreasonable handling of evidence conflicts existing in existing rockburst evaluation methods, and provides more accurate and reliable data support for rockburst risk assessment. Description of Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the accompanying drawings required for the description of the embodiments are briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other accompanying drawings based on these accompanying drawings without creative effort.

[0018] Figure 1 is a schematic flow chart of a comprehensive evaluation method for rockburst tendency of the present application; Figure 2 is a schematic diagram of a scenario for calculating an energy index of the present application; Figure 3 is a schematic diagram of a scenario for calculating a stiffness index of the present application. Detailed Description

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules is not necessarily limited to those explicitly listed, but may include other steps or modules not explicitly listed or inherent to such processes, methods, products, or devices. The naming or numbering of steps appearing in this application does not imply that the steps in the method flow must be performed in the chronological / logical order indicated by the naming or numbering. The execution order of named or numbered process steps can be changed according to the desired technical purpose, as long as the same or similar technical effect is achieved.

[0021] The module division described in this application is a logical division. In practical applications, there may be other division methods. For example, multiple modules may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection between modules shown or discussed may be through some interfaces, and the indirect coupling or communication connection between modules may be electrical or other similar forms, none of which are limited in this application. Furthermore, the modules or sub-modules described as separate components may or may not be physically separated, may or may not be physical modules, or may be distributed in multiple circuit modules. Some or all of the modules may be selected to achieve the purpose of the solution in this application according to actual needs.

[0022] First, refer to Figure 1 , Figure 1 The diagram illustrates a flowchart of the comprehensive evaluation method for rockburst tendency according to this application. The comprehensive evaluation method for rockburst tendency provided by this application may specifically include the following steps S101 to S108: Step S101: Obtain the initial index values ​​of four physical indices measured at multiple measuring points in the soil and rock area to be evaluated at the same time. The four physical indices include energy index, stiffness index, integrity index and geostress index. Understandably, in practical applications, the proposed solution can be initiated based on relevant comprehensive rockburst evaluation tasks, i.e., work tasks. For the current evaluation object, i.e., the geotechnical area to be evaluated (usually involving relevant geotechnical engineering, such as tunnel engineering or mining engineering), the specific index values ​​of multiple on-site measuring points involved in this application under four physical indicators can be directly extracted from the task information, or these specific index values ​​can be extracted from other places according to the instructions of the task information. Of course, these specific index values ​​can also be obtained through real-time acquisition and processing.

[0023] Among them, four physical indicators specifically involve energy indicators (A CF Stiffness index or brittleness index (DMI), integrity index (Kv), and ground stress index (T) Z These four indicators, in the design of this application scheme, scientifically cover the complete incubation process of rockburst from energy accumulation (energy), external driving force (geological stress), medium conditions (integrity) to final triggering (stiffness).

[0024] At the same time, considering that the four indicators are existing / mature indicators in geotechnical engineering, this application does not elaborate on the meaning of the indicators themselves here.

[0025] For these four indicators, the existing schemes have the following industry judgment standards for evaluating rockburst tendency: Table 1 - Industry Judgment Standards

[0026] Corresponding to the real-time acquisition and processing of the above four indicators, the index values ​​of the four physical indicators of the soil and rock area to be evaluated are obtained, which may specifically include: 1.1) Energy Index (A) CF ) For the soil and rock area to be evaluated, uniaxial compression tests are carried out. Based on the complete stress-strain curves obtained from the uniaxial compression (UC) tests, the total input energy density before the peak and the failure energy density after the peak are obtained. The ratio of the total input energy density before the peak to the failure energy density after the peak is calculated as an energy index.

[0027] refer to Figure 2 The diagram shown illustrates a scenario for calculating energy indices according to this application, which can be expressed by the following formula: , , , Among them, U 0 U represents the total input energy density before the peak value. aε1 represents the energy density of failure after peak strength, ε2 represents the strain at peak strength, and ε3 represents the maximum strain of the rock specimen during uniaxial compression test.

[0028] 1.2) Stiffness Index (DMI) For the soil and rock region to be evaluated, the elastic modulus before the peak value is determined based on the slope of the linear portion of the stress-strain curve before the peak value, and the post-peak reduction modulus is determined based on the slope of the stress-strain curve after the peak value. The ratio of the elastic modulus before the peak value to the post-peak reduction modulus is calculated as a stiffness index.

[0029] refer to Figure 3 The diagram shown illustrates a scenario for calculating the stiffness index in this application, which can be expressed by the following formula: , Among them, E G E represents the pre-peak elastic modulus, obtained from the slope of the linear portion of the pre-peak stress-strain curve. M This indicates the reduction in modulus after the peak value, obtained by reducing the slope of the stress-strain curve after the peak value.

[0030] 1.3) Completeness Index (K) v ) For the soil and rock area to be evaluated, the square of the ratio of the elastic longitudinal wave velocity of the rock mass to the elastic longitudinal wave velocity of the rock is used as the integrity index.

[0031] It is understandable that rockbursts typically occur within intact rock masses because intact rock masses are conducive to the storage of elastic strain energy. According to the Engineering Rock Mass Classification Standard (GB50218-94), the rock mass integrity coefficient K... v A rock mass with a rock mass integrity coefficient >0.55 is considered a relatively intact rock mass, which is a favorable condition for rockburst occurrence. On the other hand, considering the influence of the structural properties of incomplete rock masses on rockburst occurrence, the rock mass integrity coefficient is another important indicator determining rockburst occurrence. Its criterion is expressed as follows: , Among them, V pm V represents the elastic longitudinal wave velocity of the rock mass (km / s). pr This represents the elastic longitudinal wave velocity of the rock (km / s).

[0032] 1.4) Geostress index (T) Z ) For the soil and rock area to be evaluated, the ratio of the uniaxial compressive strength of the rock to the maximum principal stress is used as the geostress index.

[0033] It is understood that this application can specifically use the uniaxial compressive strength ratio to in-situ stress value as the core indicator of in-situ stress, corresponding to the following expression: , Where, σ c σ1 represents the uniaxial compressive strength of the rock, and σ1 represents the maximum principal stress (hydraulic fracturing).

[0034] Step S102: Normalize the initial index value to obtain the corresponding normalized value; Understandably, this application uses the normalization formula corresponding to each physical index to transform the initial index value into a normalized value, so that data of different dimensions and magnitudes are unified on the same scale, thus preparing data for subsequent comprehensive calculations and horizontal comparisons.

[0035] The main approach is to use the strong rockburst threshold as a normalization benchmark to convert the index value into a "risk level".

[0036] In the detailed operation, the normalization process here can be implemented using the following methods: 2.1) A CFnorm =A CF / 5 (strong rockburst threshold = 5) Among them, A CFnorm A is the normalized value corresponding to the energy index. CF It is an energy indicator.

[0037] 2.2) DMI norm =1.0 / DMI (Strong rockburst threshold = 1.0, and is an inverse indicator). Among them, DMI norm DMI is the normalized value corresponding to the stiffness index.

[0038] 2.3) K vnorm =K v / 0.75 (Strong rockburst threshold = 0.75), Among them, Kv norm K is the normalized value corresponding to the completeness index. v This is an indicator of completeness.

[0039] 2.4) T Znorm =2.5 / T Z (Strong rockburst threshold = 2.5, and is an inverse indicator). Among them, T Znorm T is the normalized value corresponding to the geostress index. Z This is an index of ground stress.

[0040] Step S103: For each physical index and each measuring point, determine the appropriate rockburst level based on the corresponding normalized value, and calculate the corresponding membership function value through the membership function adapted to the appropriate rockburst level. Understandably, for each normalized value, the degree to which it belongs to each rockburst level, namely no rockburst level, weak rockburst level, medium rockburst level, and strong rockburst level, can be quantified. This involves the matching between the normalized value and the rockburst level, as well as the matching between the rockburst level and the membership function. Suizhong calculates the specific output membership function value based on the adapted membership function.

[0041] In terms of the overall design, this application specifically designs a trapezoidal membership function for each index based on the classification of rockburst levels and index characteristics. The function forms of the positive index (the larger the value, the higher the rockburst risk) and the negative index (the smaller the value, the higher the rockburst risk) are also different to form a better differentiated processing effect.

[0042] In terms of detailed operations, the rockburst level adaptation strategy involved in this process may specifically include the following: 3.1.1) For the energy index (A) CF The normalization range is 0 ≤ A CFnorm ≤1, specifically: Corresponding to no rockburst level, A CF <2.0⇒A CFnorm <0.4; For a weak rockburst level, 2.0 ≤ A CF <3.0⇒0.4≤A CFnorm <0.6; Corresponding to medium rockburst level, 3.0≤A CF <5.0⇒0.6≤A CFnorm <1.0; Corresponding to a strong rockburst level, A CF ≥5.0⇒A CFnorm ≥1.0.

[0043] It is easy to see that this is a "trapezoidal distribution". The area without rockbursts covers the low-value area. As the value increases, the membership degree gradually transitions to a higher level. Thus, a linearly increasing membership degree function is designed for each level.

[0044] 3.1.2) For the stiffness index (DMI), the normalized range is DMI. norm ≥1.0, specifically including: For the no-rockburst rating, DMI > 1.0 ⇒ DMI norm <1.0; For medium rockburst levels, DMI≤1.0⇒DMI norm ≥1.0.

[0045] 3.1.3) Regarding the completeness index (K) v ), and energy index (A CF Similarly, these are also positive indicators, specifically: Corresponding to the no-rockburst level, K v <0.35⇒K vnorm <0.4667; For a weak rockburst level, 0.35≤K v <0.55⇒0.4667≤K vnorm <0.7333; For medium rockburst level, 0.55≤K v <0.75⇒0.7333≤K vnorm <1.0; Corresponding to the strong rockburst level, K v ≥0.75⇒K vnorm ≥1.0.

[0046] 3.1.4) Regarding the geostress index (TZ), specifically: Corresponding to the no-rockburst level, T Z >14.5⇒T Znorm <0.172; For a weak rockburst level, 5.5≤T Z ≤14.5⇒0.172≤T Znorm ≤0.4545; Corresponding to a medium rockburst level, 2.5 <T Z <5.5⇒T Znorm <1.0; Corresponding to the strong rockburst level, T Z ≤2.5⇒T Znorm ≥1.0.

[0047] Corresponding to the rockburst level matching strategy described above, the membership function adaptation strategy involved in this processing may specifically include the following: 3.2.1) For the energy index (A) CF Specifically, these include: Corresponding to the no-rockburst level, when x < 0.4, μ ACF (x)=1, where μ Q (x) is the quantified value of the membership function of the Q index under the normalized value x of the input index in the function. Q is obviously A in different stages. CF DMI, K v and T Z ; For a weak rockburst level, when 0.4 ≤ x < 0.6, μ ACF (x) = (x - 0.4) / 0.2; For medium rockburst levels, when 0.6 ≤ x < 1.0, μ ACF (x) = (x - 0.6) / 0.4; For a strong rockburst level, when x ≥ 1.0, μACF (x)=1.

[0048] 3.2.2) Regarding the stiffness index (DMI), the previous rockburst classification only had two levels. Further subdivision of the boundaries between weak, medium, and strong rockbursts is needed. It is assumed that the threshold for medium rockburst is 1.0 ≤ DMI. norm <2.0, strong rockburst at DMI norm ≥2.0, specifically, includes: Corresponding to the no-rockburst level, μ DMI (x)=1, when x<1.0; For a weak rockburst level, when 1.0 ≤ x < 1.5, μ DMI (x) = (x - 1.0) / 0.5; For the corresponding medium rockburst level, when 1.5 ≤ x < 2.0, μ DMI (x) = (x - 1.5) / 0.5; For a strong rockburst level, when x ≥ 2.0, μ DMI (x)=1.

[0049] 3.2.3) Regarding the completeness index (K) v ), Corresponding to the no-rockburst level, when x < 0.4667, μ Kv (x)=1; For a weak rockburst level, when 0.4667 ≤ x < 0.7333, μ Kv (x) = (x - 0.4667) / 0.2666; For a medium rockburst level, when 0.7333 ≤ x < 1.0, μ Kv (x) = (x - 0.7333) / 0.2667; For a strong rockburst level, when x ≥ 1.0, μ Kv (x)=1.

[0050] 3.2.4) Regarding the geostress index (T) Z ), Corresponding to the no-rockburst level, when x < 0.172, μ TZ (x)=1; For a weak rockburst level, when 0.172 ≤ x < 0.4545, μ TZ (x) = (x - 0.172) / 0.2825; For the corresponding medium rockburst level, when 0.4545 ≤ x < 1.0, μ TZ (x) = (x - 0.4545) / 0.5455; For a strong rockburst level, when x ≥ 1.0, μ TZ (x)=1.

[0051] Thus, the membership values ​​of the index at each rockburst level were calculated by combining normalization processing, and the sum of the confidence levels of each level was made to be 1.

[0052] Step S104: For each physical index, under the condition of following the Dempster-Shafer evidence theory, construct a basic probability assignment based on the membership function value to obtain the basic probability value corresponding to each rockburst level. Understandably, this application specifically introduces the Dempster-Shafer evidence theory (or DS method), which involves the previous level allocation, the basic probability allocation (BPA) here, and several subsequent processing steps.

[0053] However, it should be noted that the focus of this application is not simply the application of Dempster-Shafer evidence theory. The specific processing analysis required in different processing stages, such as the selection of specific indicators, how to perform normalization, and how to classify levels based on thresholds, requires in-depth configuration work in combination with the specific application scenario in order to achieve the purpose of this application.

[0054] Understandably, the purpose of the basic probability allocation here is to construct a basic probability allocation for each indicator based on the membership function, and to assign the confidence level of the indicator to different rockburst levels.

[0055] In terms of specific operations, for each indicator, a basic probability allocation is calculated based on its membership value at different rockburst levels. Assuming the membership degree of a certain indicator at rockburst level i is... The basic probability allocation can be performed according to the following formula: , in, Let i be the probability value assigned to the current indicator at level i, where i = 1, 2, 3, 4, corresponding to no rockburst level, weak rockburst level, medium rockburst level, and strong rockburst level, respectively. This represents the membership function value of the current indicator at level i. This is the sum of the membership function values ​​for all levels of the current indicator.

[0056] Step S105: For each pair of physical indicators, calculate the corresponding conflict coefficient based on the basic probability value corresponding to the basic probability allocation. After determining the basic probability distribution of different physical indicators, the four physical indicators can be combined in pairs to form multiple indicator pairs. For each pair of physical indicators, the Dempster-Shafer evidence theory can be used to calculate the corresponding conflict coefficient (which can be denoted as K) to measure the difference in the degree of support of different evidence (indicators) for the rockburst level.

[0057] In terms of specific operations, the rockburst levels supported by the two pairs of evidence can be compared to find the conflicting parts and calculate the conflict coefficient.

[0058] Specifically, the conflict coefficient for each pair of physical indices can be calculated using the following formula: , Where K is the conflict coefficient. The probability value is obtained by assigning the set of rockburst grades A supported by the first indicator in the paired indicators to the basic probability distribution. Let A∩B=Ø be the probability value obtained by assigning the set of rockburst grades B supported by the second indicator in the pairwise indicators to the basic probability distribution. A∩B=Ø means that the two sets of rockburst grades have no intersection, that is, the support of the two indicators for the rockburst grades does not overlap at all.

[0059] The above formula quantifies the degree of conflict between two indicators by summing the product of the probability values ​​of the basic probability distributions of all non-overlapping parts. In this case, the conflict coefficient K ranges from 0 to 1, and the larger the value, the more severe the conflict.

[0060] Step S106: Based on the conflict coefficients of the pairs of physical indicators, the probability distributions of the basic correspondences are fused using the Dempster rule to obtain the corresponding comprehensive confidence levels of the pairs of physical indicators. After obtaining the conflict coefficient K for each pair of physical indicators, we can continue to perform basic probability allocation fusion under the Dempster rule for each pair of physical indicators, or in other words, using indicator pairs as the processing unit, to obtain the comprehensive confidence level at the indicator pair level.

[0061] Let the basic probability distributions of the two indicators in each pair of physical indicators be respectively and The overall confidence level of each pair of physical indicators can be calculated using the following formula: , in, The comprehensive confidence level of input X is X, which is a set of rockburst levels, specifically the intersection of rockburst level set A and rockburst level set B. A∩B=X means that the intersection of the rockburst level sets supported by the two indicators is X.

[0062] Step S107: The comprehensive confidence scores of the paired physical indicators are integrated into a single comprehensive index by weighted summation, wherein the weight allocation is based on the importance of each indicator to rockburst prediction. After obtaining the overall confidence level of each pair of physical indicators, a final comprehensive index can be obtained from the overall perspective. The purpose of this process is to integrate the overall confidence levels of the four rockburst levels into a single comprehensive index through weighted summation. In this way, the rockburst tendency level can be determined based on the value range of the comprehensive index.

[0063] In terms of specific operations, the weights of each indicator combination can be determined, and the comprehensive index can be obtained by multiplying the comprehensive confidence level of each combination by its weight and summing the results.

[0064] Specifically, the comprehensive index that directly corresponds to the rockburst tendency level can be calculated using the following formula: , Where IBI is the composite index, and n is the total number of indicator pairs. Let the weight of the indicator pair be the weight of the i-th indicator pair. Let be the overall confidence level of the i-th indicator for the corresponding level j. Let j be the weight of the level. Specifically, the above formula indicates that the comprehensive index is obtained by multiplying the weights of each pair of indicators, the overall confidence level after fusion, and the weight of the rockburst level, and then summing them up. It comprehensively considers the contribution of each indicator to the rockburst tendency and finally gives a single value to represent the probability and level of rockburst occurrence.

[0065] The weights reflect the relative importance of each indicator in rockburst prediction. Based on the rockburst mechanism and engineering experience, the energy index (A) is used. CF ) and geostress index (T) Z These factors have a significant impact on the occurrence of rockbursts, therefore they have a higher weight.

[0066] Thus, as an example, we can have: Energy Index (A) CF ): 40%, geostress index (T) Z ): 25%, Stiffness index (DMI): 15%, Integrity index (K) v ): 20%.

[0067] Under the principle that the sum of the weights of all indicator pairs must be 1, as an example, the weights of each indicator pair are as follows: Energy Index (A) CF Stiffness index (DMI): 0.168 Energy Index (A) CF) & Integrity Index (K v ): 0.224 Energy Index (A CF ) & In-situ Stress Index (T Z ): 0.279 Stiffness Index (DMI) & Integrity Index (K v ): 0.084 Stiffness Index (DMI) & In-situ Stress Index (T Z ): 0.140 Integrity Index (K v ) & In-situ Stress Index (T Z ): 0.105 Step S108: determining a target rockburst tendency grade corresponding to the geotechnical area to be evaluated under the current condition according to the comprehensive index, and outputting the result.

[0068] As introduced above, after obtaining the comprehensive index in the form of a numerical value, the specific rockburst tendency condition and grade directly corresponding to the comprehensive index can be determined, which involves a pre-configured correspondence.

[0069] Correspondingly, the specific correspondence between different comprehensive indexes and different rockburst tendency grades is as follows: IBI≤1.0: No rockburst tendency; 1.0<IBI<2.0: Weak rockburst tendency; 2.0<IBI<3.0: Medium rockburst tendency; IBI≥3.0: Strong rockburst tendency.

[0070] In this way, with corresponding specific quantification formulas involved in multiple stages, the solution of the present application comprehensively considers the influence of multiple indicators on rockburst tendency, and provides a quantitative basis for rockburst risk assessment.

[0071] At this time, after determining the target rockburst tendency grade (specific rockburst tendency condition) corresponding to the geotechnical area to be evaluated under the current condition, the processing result can be output.

[0072] In specific operations, the output operations may include local storage, remote storage, result display, result pushing, prompt of output completion evaluation, corresponding rockburst early warning on software and hardware, or further data processing and analysis, etc.

[0073] It is easy to understand that the specifically configured output operations in practical applications can be flexibly configured according to actual needs.

[0074] In conclusion, regarding the above-mentioned solutions, this application, through scientific dimensionless processing and DS evidence fusion theory, effectively solves the problems of inconsistent benchmarks and unreasonable handling of evidence conflicts in existing rockburst assessment methods, providing more accurate and reliable data support for rockburst risk assessment, in order to achieve the comprehensive evaluation target of rockburst tendency.

[0075] In terms of details, traditional methods habitually use CRITIC, PCA, AHP and other methods to determine weights. For example, the CRITIC method determines weights based on objective information of indicator data, but does not consider physical mechanisms and engineering experience, and the weights lack clear physical meaning. Another example is the AHP method, which relies on expert scoring to determine weights, which is highly subjective. These methods lack systematicity when dealing with conflicts between multiple indicators and are difficult to effectively resolve conflicts.

[0076] In contrast, the proposed solution deeply integrates physical mechanisms and engineering experience to determine weights, and automatically resolves index conflicts through DS evidence theory, giving the weights clear physical meaning and overcoming the shortcomings of traditional methods.

[0077] To illustrate the differences in technical features, the following comparison table is provided: Table 2 - Comparison of Effect Differences

[0078] To better understand the above solutions, we can also use the following set of relatively complete examples for illustration.

[0079] (I) Assume the measured values ​​of the four indicators are as follows: Energy Index (A) CF : 5.0 (Strong Rockburst) Stiffness index (DMI): 0.5 (strong rockburst). Completeness index (K v : 0.6 (medium rock burst) In-situ stress (TZ): 5.0 (medium rockburst).

[0080] (II) Normalization Calculation Process: A CF A CFnorm =5.0 / 5=1.0, DMI: DMI norm =1.0 / 0.7≈1.43, Kv:Kv norm =0.6 / 0.75=0.8, TZ:T Znorm =2.5 / 5.0=0.5.

[0081] (III) Definition of Membership Function and Construction of Basic Probability Assignment 1. Energy Indicators (A) CF ) Normalized value: A CFnorm =1.0, Membership function: No rockburst: μ ACF (x) = 0 (x < 0.4), Weak rockburst: μ ACF (x) = 0 (0.4 ≤ x < 0.6). Mid-rockburst: μ ACF (x) = 0 (0.6 ≤ x < 1.0). Strong rockburst: μ ACF (x) = 1 (x ≥ 1.0), Constructing the basic probability assignment: No rockburst = 0, weak rockburst = 0, medium rockburst = 0, strong rockburst = 1.0.

[0082] 2. Stiffness Index (DMI) Normalized value: DMI norm =1.43, Membership function: No rockburst: μ DMI (x) = 0 (x < 1.0), Weak rockburst: μ DMI (x)=(1.43-1.0) / 0.5=0.86(1.0≤x<1.5), Mid-rockburst: μ DMI (x) = 0 (1.5 ≤ x < 2.0). Strong rockburst: μ DMI (x) = 0 (x ≥ 2.0), Constructing the basic probability assignment: B No rockburst = 0, weak rockburst = 0.86, medium rockburst = 0, strong rockburst = 0.

[0083] 3. Completeness Index (Kv) Normalized value: K vnorm =0.8, Membership function: No rockburst: μ Kv (x)=0 (x<0.4667). Weak rockburst: μ Kv (x)=0 (0.4667≤x<0.7333), Mid-rockburst: μ Kv (x)=(0.8-0.7333) / 0.2667=0.25(0.7333≤x<1.0), Strong rockburst: μ Kv (x) = 0 (x ≥ 1.0), Constructing the basic probability assignment: No rockburst = 0, weak rockburst = 0, medium rockburst = 0.25, strong rockburst = 0.

[0084] 4. Geostress (T) Z ) Normalized value: T Znorm =0.5, Membership function: No rockburst: μ TZ (x) = 0 (x < 0.172). Weak rockburst: μ TZ (x)=0 (0.172≤x<0.4545), Mid-rockburst: μ TZ (x)=(0.5-0.4545) / 0.5455≈0.0837(0.4545≤x<1.0), Strong rockburst: μ TZ (x) = 0 (x ≥ 1.0), Constructing the basic probability assignment: No rockburst = 0, weak rockburst = 0, medium rockburst = 0.0837, strong rockburst = 0.

[0085] (iv) Calculation of conflict coefficient: Calculate the conflict coefficient K between each pair of indicators: A CF And DMI: Calculation formula: K=Σ[A∩B=Ø]m ACF (A)m DMI (B), Calculation result: K = 1.0 × 0.86 + 0.86 × 1.0 = 1.86 (approximately 1.0 after normalization). A CF And Kv: Calculation formula: K=Σ[A∩B=Ø]m ACF (A)m Kv (B), Calculation result: K = 1.0 × 0.25 + 0.25 × 1.0 = 0.5 A CF and T Z : Calculation formula: K=Σ[A∩B=Ø]m ACF (A)m TZ (B), Calculation result: K = 1.0 × 0.0837 + 0.0837 × 1.0 = 0.1674 DMI and Kv: Calculation formula: K=Σ[A∩B=Ø]m DMI (A)m Kv (B), Calculation result: K = 0.86 × 0.25 + 0.25 × 0.86 = 0.43 DMI and TZ: Calculation formula: K=Σ[A∩B=Ø]m DMI (A)m TZ (B), Calculation result: K = 0.86 × 0.0837 + 0.0837 × 0.86 = 0.144 Kv and TZ: Calculation formula: K=Σ[A∩B=Ø]m Kv (A)m TZ (B), Calculation result: K=0.25×0.0837+0.0837×0.25=0.0418.

[0086] (iv) Calculation of integrated confidence level: 1.A CF Integration with DMI A CF BPA: Strong Rockburst = 1.0 DMI's BPA: Weak rockburst = 0.86 Conflict coefficient: K=1.0 (complete conflict) Fusion result: Fusion is not possible due to a conflict coefficient of 1.

[0087] 2.A CF Integration with KV A CF BPA: Strong Rockburst = 1.0 Kv's BPA: Medium Rockburst = 0.25 Conflict coefficient: K=0.5 Fusion computing: Total confidence level: 1.0 (strong rockburst at ACF) + 0.25 (medium rockburst at Kv) = 1.25 After fusion, BPA is calculated as follows: Strong rockburst = 1.0 / 1.25 = 0.8, Medium rockburst = 0.25 / 1.25 = 0.2. Result: Strong rockburst has a higher overall confidence level.

[0088] 3.A CF and T Z Fusion A CF BPA: Strong Rockburst = 1.0 TZ BPA: Medium rockburst = 0.0837 Conflict coefficient: K≈0.1674 Fusion computing: Total confidence level: 1.0 (A) CF (strong rockburst) +0.0837 (T) Z (Medium rockburst) = 1.0837, After fusion, BPA: Strong rockburst = 1.0 / 1.0837 ≈ 0.9227, Medium rockburst = 0.0837 / 1.0837 ≈ 0.0773. Result: Strong rockburst has a higher overall confidence level.

[0089] 4. Integration of DMI and KV DMI's BPA: Weak rockburst = 0.86 Kv's BPA: Medium Rockburst = 0.25 Conflict coefficient: K=0.43 Fusion computing: Total confidence level: 0.86 (weak rockburst at DMI) + 0.25 (medium rockburst at Kv) = 1.11 After fusion, BPA values ​​are: weak rockburst = 0.86 / 1.11 ≈ 0.7748, medium rockburst = 0.25 / 1.11 ≈ 0.2252. Result: The overall confidence level of weak rockburst is higher.

[0090] 5. DMI and T Z Fusion DMI's BPA: Weak rockburst = 0.86 T Z BPA: Medium rockburst = 0.0837 Conflict coefficient: K≈0.144 Fusion computing: Total confidence level: 0.86 (weak rockburst at DMI) + 0.0837 (T Z (Medium rockburst) = 0.9437, After fusion, BPA is calculated as follows: Weak rockburst = 0.86 / 0.9437 ≈ 0.9113, Medium rockburst = 0.0837 / 0.9437 ≈ 0.0887. Result: The overall confidence level of weak rockburst is higher.

[0091] 6. Kv and T Z Fusion Kv's BPA: Medium Rockburst = 0.25 T Z BPA: Medium rockburst = 0.0837 Conflict coefficient: K≈0.04185 Fusion computing: Total confidence level: 0.25 (Kv for medium rockburst) + 0.0837 (T) Z The value of the rock burst (in the middle) is 0.3337. The fused BPA: medium rockburst = (0.25 + 0.0837) / (1 - 0.04185) ≈ 0.3337 / 0.95815 ≈ 0.3482. Result: The overall confidence level of the rockburst increased.

[0092] Based on the above fusion results, the overall confidence level of each pair of indicators is as follows: A CF DMI: Conflict coefficient K=1.0, cannot be fused, and the overall confidence level cannot be calculated; therefore, it is ignored in the IBI calculation. A CF With Kv: The combined BPA is 0.8 for strong rockburst and 0.2 for medium rockburst. A CF and T Z The combined BPA is approximately 0.9227 for strong rockburst and 0.0773 for medium rockburst. DMI and Kv: The combined BPA is approximately 0.7748 for weak rockburst and 0.2252 for medium rockburst. DMI and T Z The combined BPA values ​​are approximately 0.9113 for weak rockburst and 0.0887 for medium rockburst. Kv and T Z The fused BPA is approximately 0.3482 for medium rockburst.

[0093] (vi) Calculation of the Composite Index (IBI): To calculate IBI, the fusion result of each pair of indicators needs to be multiplied by the corresponding rockburst level weight, and then weighted and summed.

[0094] The weighting for rockburst severity is as follows: No rockburst = 1 Weak rockburst = 2, Medium rock burst = 3, Strong rockburst = 4.

[0095] The weighting of each indicator pair is as follows: A CF &DMI: 0.168, A CF &K v 0.224, A CF &T Z 0.279, DMI&K v 0.084 DMI&T Z 0.140, K v &T Z : 0.105.

[0096] The fusion result of each pair of indicators is combined with its weight and rockburst level weight for calculation: A CF and K v : The overall confidence level for a strong rockburst is 0.8, corresponding to a rockburst level weight of 4. Contribution: 0.224 × 0.8 × 4 = 0.7168 The overall confidence level for a moderate rockburst is 0.2, corresponding to a rockburst level weight of 3. Contribution: 0.224 × 0.2 × 3 = 0.1344 Total: 0.7168 + 0.1344 = 0.8512.

[0097] A CF and T Z : The overall confidence level of a strong rockburst is approximately 0.9227, corresponding to a rockburst level weight of 4.

[0098] Contribution: 0.279 × 0.9227 × 4 ≈ 1.033 The overall confidence level for a moderate rockburst is approximately 0.0773, corresponding to a rockburst severity weight of 3. Contribution: 0.279 × 0.0773 × 3 ≈ 0.066 Total: 1.033 + 0.066 ≈ 1.099.

[0099] DMI and K v : The overall confidence level for a weak rockburst is approximately 0.7748, corresponding to a rockburst level weight of 2. Contribution: 0.084 × 0.7748 × 2 ≈ 0.130 The overall confidence level for a moderate rockburst is approximately 0.2252, corresponding to a rockburst severity weight of 3. Contribution: 0.084 × 0.2252 × 3 ≈ 0.055 Total: 0.130 + 0.055 ≈ 0.185.

[0100] DMI and T Z : The overall confidence level for a weak rockburst is approximately 0.9113, corresponding to a rockburst level weight of 2. Contribution: 0.140×0.9113×2≈0.255, the comprehensive confidence of medium rock burst≈0.0887, corresponding rock burst grade weight=3, Contribution: 0.140×0.0887×3≈0.037, Total: 0.255+0.037≈0.292.

[0101] Kv and T Z : the comprehensive confidence of medium rock burst≈0.3482, corresponding rock burst grade weight=3, Contribution: 0.105×0.3482×3≈0.106.

[0102] A CF and DMI: since fusion cannot be performed, the contribution thereof is 0.

[0103] All contributions are added to obtain IBI: IBI=0.8512+1.099+0.185+0.292+0.106=2.533.

[0104] According to the IBI classification criteria: IBI≤1.0: no rock burst, 1.0<IBI<2.0: weak rock burst, 2.0≤IBI<3.0: medium rock burst, IBI≥3.0: strong rock burst.

[0105] IBI=2.533, indicating that the current rock burst propensity grade is medium rock burst.

[0106] The above provides a detailed introduction of the comprehensive evaluation method for rock burst propensity provided by the present application. Specific examples are used herein to illustrate the principle and implementation of the present application. The descriptions of the above embodiments are only used to help understand the core idea of the present application. Meanwhile, for those skilled in the art, changes may be made to the specific implementation and application scope according to the idea of the present application. In conclusion, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A comprehensive evaluation method for rockburst tendency, characterized in that, The method includes: The initial values ​​of four physical indices are obtained from multiple measuring points in the soil and rock area to be evaluated at the same time. The four physical indices include energy index, stiffness index, integrity index and geostress index. The initial index value is normalized to obtain the corresponding normalized value; For each physical index and each measuring point, the appropriate rockburst level is determined based on the corresponding normalized value, and the corresponding membership function value is calculated through the membership function adapted to the appropriate rockburst level. For each of the physical indicators, under the condition of following the Dempster-Shafer evidence theory, a basic probability assignment is constructed based on the membership function value to obtain the basic probability value corresponding to each of the rockburst levels; For each pair of physical indicators, the corresponding conflict coefficient is calculated based on the basic probability value corresponding to the basic probability allocation. Based on the conflict coefficients of the paired physical indicators, the corresponding basic probability assignments are fused using the Dempster rule to obtain the corresponding comprehensive confidence levels of the paired physical indicators. The combined confidence scores of the paired physical indicators are integrated into a single composite index by weighted summation, wherein the weights are allocated based on the importance of each indicator to rockburst prediction. The target rockburst tendency level for the soil and rock area to be evaluated under the current conditions is determined based on the comprehensive index and output. The initial index values ​​of four physical indicators measured simultaneously at multiple measuring points in the soil and rock area to be evaluated include: For the soil and rock area to be evaluated, a uniaxial compression test is carried out. Based on the complete stress-strain curve obtained from the uniaxial compression test, the total input energy density before the peak and the failure energy density after the peak are obtained. The ratio of the total input energy density before the peak to the failure energy density after the peak is calculated as the initial index value of the energy index. For the soil and rock region to be evaluated, the pre-peak elastic modulus is determined based on the slope of the linear portion of the pre-peak stress-strain curve, and the post-peak reduction modulus is determined based on the slope of the post-peak stress-strain curve. The ratio of the pre-peak elastic modulus to the post-peak reduction modulus is calculated as the initial index value of the stiffness index. For the soil and rock area to be evaluated, the square of the ratio of the elastic longitudinal wave velocity of the rock mass to the elastic longitudinal wave velocity of the rock is used as the initial index value of the integrity index. For the soil and rock area to be evaluated, the ratio of the uniaxial compressive strength of the rock to the maximum principal stress is used as the initial index value of the geostress index.

2. The method according to claim 1, characterized in that, The normalization process includes the following steps: A CFnorm =A CF / 5, where A CFnorm For the normalized value corresponding to the energy index, A CF The energy index; DMI norm =1.0 / DMI, where DMI norm DMI is the normalized value corresponding to the stiffness index; Kv norm =Kv / 0.75, where Kv norm Kv is the normalized value corresponding to the completeness index; T Znorm =2.5 / TZ, where T Znorm For the normalized value corresponding to the aforementioned geostress index, T Z The term refers to the geostress index.

3. The method according to claim 2, characterized in that, The rockburst level adaptation strategy includes the following: For the aforementioned energy index, corresponding to the no-rockburst level, A CFnorm <0.4; corresponds to a weak rockburst level, 0.4≤A CFnorm <0.6; corresponding to medium rockburst level, 0.6≤A CFnorm <1.0; corresponds to a strong rockburst level, A CFnorm ≥1.0; For the stiffness index, corresponding to the rockburst-free rating, DMI norm <1.0; corresponding to the aforementioned medium rockburst level, DMI norm ≥1.0; For the aforementioned integrity index, corresponding to the rockburst-free level, Kv norm <0.4667; corresponding to the weak rockburst level, 0.4667≤Kv norm <0.7333; corresponding to the aforementioned medium rockburst level, 0.7333≤Kv norm <1.0; corresponding to the aforementioned strong rockburst level, Kv norm ≥1.0; For the aforementioned geostress index, corresponding to the rockburst-free level, T Znorm <0.172; corresponding to the weak rockburst level, 0.172≤T Znorm ≤0.4545; corresponding to the aforementioned medium rockburst level, T Znorm <1.0; corresponding to the aforementioned strong rockburst level, T Znorm ≥1.0; Membership function adaptation strategies include the following: For the energy index, corresponding to the rockburst-free level, when x < 0.4, μ ACF (x)=1, μ Q (x) is the membership function quantification value of the Q index under the normalized value x of the input index; corresponding to the weak rockburst level, when 0.4 ≤ x < 0.6, μ ACF (x) = (x - 0.4) / 0.2; corresponding to the aforementioned rockburst level, when 0.6 ≤ x < 1.0, μ ACF (x) = (x - 0.6) / 0.4; corresponding to the aforementioned strong rockburst level, when x ≥ 1.0, μ ACF (x)=1; For the stiffness index, corresponding to the rockburst-free level, μ DMI (x)=1, when x<1.0; corresponding to the weak rockburst level, when 1.0≤x<1.5, μ DMI (x) = (x - 1.0) / 0.5; corresponding to the aforementioned rockburst level, when 1.5 ≤ x < 2.0, μ DMI (x) = (x - 1.5) / 0.5; corresponding to the strong rockburst level, when x ≥ 2.0, μ DMI (x)=1; For the integrity index, corresponding to the rockburst-free level, when x < 0.4667, μ Kv (x)=1; corresponding to the weak rockburst level, when 0.4667≤x<0.7333, μ Kv (x) = (x - 0.4667) / 0.2666; corresponding to the aforementioned rockburst level, when 0.7333 ≤ x < 1.0, μ Kv ((x) = (x - 0.7333) / 0.2667; corresponding to the strong rockburst level, when x ≥ 1.0, μ Kv (x)=1; For the aforementioned geostress index, corresponding to the rockburst-free level, when x < 0.172, μ TZ (x)=1; corresponding to the weak rockburst level, when 0.172≤x<0.4545, μ TZ (x) = (x - 0.172) / 0.2825; corresponding to the aforementioned medium rockburst level, when 0.4545 ≤ x < 1.0, μ TZ (x) = (x - 0.4545) / 0.5455; corresponding to the aforementioned strong rockburst level, when x ≥ 1.0, μ TZ (x)=1.

4. The method according to claim 3, characterized in that, The basic probability assignment follows the following formula: ， in, The probability values ​​assigned to the current indicator at level i, i=1,2,3,4, correspond to the no-rockburst level, the weak rockburst level, the medium rockburst level, and the strong rockburst level, respectively. The membership function value of the current indicator at level i. It is the sum of the membership function values ​​for all levels of the current indicator.

5. The method according to claim 4, characterized in that, The conflict coefficient is calculated using the following formula: ， Where K is the conflict coefficient. The probability value is the set of rockburst levels A supported by the i-th indicator in the paired indicators, obtained through the basic probability allocation. The probability value is the set of rockburst grades B supported by the j-th index in the paired indices, obtained by the basic probability allocation. A∩B=Ø indicates that the two sets of rockburst grades have no intersection.

6. The method according to claim 5, characterized in that, The overall confidence level for each pair of physical indicators is calculated using the following formula: ， in, The comprehensive confidence level of input X is the intersection of the rockburst level set A and the rockburst level set B. A∩B=X means that the intersection of the rockburst level sets supported by the two indicators is X.

7. The method according to claim 6, characterized in that, The composite index is calculated using the following formula: ， Wherein, IBI is the composite index, and n is the total number of indicator pairs. Let the weight of the indicator pair be the weight of the i-th indicator pair. Let be the overall confidence level of the i-th indicator for the corresponding level j. Let be the level weight of level j.

8. The method according to claim 7, characterized in that, The different rockburst tendency levels corresponding to the different comprehensive indices have the following specific relationships: IBI≤1.0: No tendency for rockbursts; 1.0<IBI<2.0: weak rock burst tendency; 2.0<IBI<3.0: medium rock burst tendency; IBI≥3.0: strong rock burst tendency.

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