A quantitative evaluation method for rock burst tendency of surrounding rock under multiple disturbances

Abstract

The present application belongs to the field of rock burst risk assessment of deep rock engineering, and particularly relates to a quantitative evaluation method for rock burst tendency of surrounding rock under multiple disturbances, which comprises the following steps: obtaining the distribution depth of excavation damage zone through acoustic testing, and obtaining the average wave velocity of rock mass in the range of original rock zone; obtaining the geological strength index and disturbance factor through the average wave velocity; further obtaining the residual elastic energy of surrounding rock based on the geological strength index and disturbance factor, and evaluating the rock burst tendency of surrounding rock through the residual elastic energy of surrounding rock; the acoustic testing points of surrounding rock are unchanged, and the rock burst tendency of surrounding rock is evaluated after each excavation footage of the working face is completed, until the distribution characteristics of rock burst tendency no longer change obviously, which is taken as the long-term evaluation result of rock burst tendency of surrounding rock. The quantitative evaluation formula of rock burst tendency of surrounding rock considers the rock mass structure effect, which is reflected in the geological strength index, and considers the excavation disturbance effect, which is consistent with the actual situation of engineering construction process, and has strong practicability.

Description

Technical Field

[0001] This invention belongs to the field of rockburst risk assessment in deep rock engineering, and specifically relates to a quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances. Background Technology

[0002] Rockburst is a common geological hazard during deep rock engineering excavation, seriously threatening the safety of machinery and personnel. Rockburst tendency characterizes the intensity of a rockburst; a higher tendency indicates a more violent rock or rock mass during a rockburst, resulting in greater damage. In deep engineering excavation, the surrounding rock is frequently disturbed by the excavation face. Quantitatively evaluating the rockburst tendency of the surrounding rock under multiple disturbances is of significant reference value for rockburst risk assessment, prevention and control plan development, and support scheme optimization.

[0003] Under high geostress conditions, rock masses store a large amount of elastic energy. When disturbed by excavation, this energy is suddenly released, leading to rockbursts. Therefore, rockbursts are essentially a process of rapid energy release. Based on this, some scholars have proposed using the elastic energy index W... ET Energy Impact Index A CF Elastic strain potential energy (PES) and residual elastic energy index (A) EF Indicators such as the residual elastic energy index A are used to evaluate the rockburst tendency of rock materials. EF Because it considers the absolute difference between the pre-peak elastic energy and the post-peak destructive energy, and the discrimination criterion is based on the actual failure characteristics of the rock and qualitative characteristics such as the far-field ejection mass ratio, it is more reasonable than other indicators. Numerous experimental results have also confirmed its ability to accurately determine the rockburst tendency of rock materials. However, in actual engineering projects, the surrounding rock contains structural planes and is subjected to multiple excavation disturbances. These disturbances may alter the rockburst tendency of the surrounding rock. The existing rockburst tendency discrimination methods do not consider the rock mass structure and disturbance conditions, making it difficult to accurately assess the rockburst tendency of the surrounding rock under multiple disturbances. Therefore, proposing a quantitative evaluation method for the rockburst tendency of the surrounding rock under multiple disturbances is of greater practical significance. Summary of the Invention

[0004] This invention provides a quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances, addressing the aforementioned problems.

[0005] The present invention adopts the following technical solution:

[0006] A quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances, comprising the following steps:

[0007] Step 1: Conduct acoustic wave testing on the surrounding rock to measure the P-wave velocity at different depths from the excavation profile; obtain the depth h of the excavation damage zone distribution. EDZThe original rock zone; the average wave velocity v of the rock mass within the original rock zone. a-p0 ;

[0008] Step 2: Utilize the average wave velocity v of the original rock mass in Step 1. a-p0 Calculate the geological strength index (GSI); determine the disturbance factor (D) at different depths;

[0009] Step 3: Based on the disturbance factor D at different depths in Step 2, the excavation damage zone of the surrounding rock is divided into: high damage zone and weak damage zone;

[0010] Calculate the distribution depth of the highly damaged zone and the weakly damaged zone to obtain a function describing the continuous change of the disturbance factor D in the surrounding rock with increasing depth;

[0011] Step 4: Calculate the residual elastic energy A of the surrounding rock based on the continuous variation function of the geological strength index GSI and the disturbance factor D obtained in Step 2. EF Through the residual elastic energy A of the surrounding rock EF Evaluate the rockburst tendency of the surrounding rock;

[0012] Step 5: Keep the acoustic test points in the surrounding rock unchanged. Repeat steps 1-4 after each excavation advance at the working face to assess the rockburst tendency of the surrounding rock until the distribution characteristics of the rockburst tendency no longer change significantly. The evaluation result at this time can be regarded as the rockburst tendency of the surrounding rock that no longer changes after multiple disturbances, and can be used as the long-term evaluation result of the rockburst tendency of the surrounding rock during subsequent excavation.

[0013] A quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances; Step 1 is as follows:

[0014] (1) Conduct acoustic testing in accordance with national standards (GB 50021-2001(2009) Code for Geotechnical Engineering Investigation, etc.) or industry standards (such as SL / T 264-2020 Code for Rock Testing in Water Conservancy and Hydropower Engineering, etc.);

[0015] (2) Since the P-wave velocity in the excavated damaged zone is significantly lower than that in the original rock zone, the depth of the low-velocity zone is considered as the distribution depth h of the EDZ in the excavated damaged zone. EDZ (m), areas with relatively stable wave velocity changes are considered as the original rock zone, and the average wave velocity within the original rock zone is taken as the average wave velocity v of the rock mass in the original rock zone. a-p0 (km / s).

[0016] A quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances; Step 2 is as follows:

[0017] (1) Based on the research of Serafim and Pereira and Barton, the rock mass geomechanical classification system RMR 76Seismic wave P-wave velocity V with rock mass s-p (km / s) has the following quantitative relationship:

[0018]

[0019] Seismic P-wave velocity and V s-p With the velocity v of sound wave P a-p A good linear relationship exists (correlation coefficient can reach 0.97). Based on linear fitting of a large amount of engineering data, the linear relationship represented by the fitted curve equation is as follows:

[0020] V s-p =0.893v a-p +0.151 (2)

[0021] Substituting formula (2) into formula (1), we get:

[0022] RMR 76 =11.907v a-p +5.347 (3)

[0023] According to Hoek and Diederichs' research, GSI = RMR 76 Therefore, according to formula (3), GSI can be expressed as:

[0024] GSI = 11.907v a-p +5.347 (4)

[0025] The average wave velocity v of the rock mass within the original rock zone determined in step 1. a-p0 The geological strength index (GSI) of the surrounding rock is expressed as follows:

[0026] GSI = 11.907v a-p0 +5.347 (5)

[0027] The geological strength index (GSI) of the surrounding rock can be quantitatively calculated using formula (5).

[0028] (2) According to the research of Hoek et al., the deformation modulus E of the rock mass rm (GPa) and the deformation modulus E of the original rock mass rm0 The ratio of (GPa) can be expressed as:

[0029]

[0030] In the formula, D is the disturbance factor, which can be used to characterize the degree of disturbance of the surrounding rock caused by blasting and unloading. The disturbance factor of the excavated damaged zone is 1≤D<0, and the original rock zone is D=0. In the Hoek-Brown guidelines of 2002 and 2018, only a few qualitative descriptions are given to determine the disturbance factor D, and no quantitative estimation method is given, which is difficult to apply to actual engineering.

[0031] According to the research of Galera et al., the rock mass deformation modulus E rm Available rock elastic modulus E i (GPa) and the Rock Geomechanical Classification System RMR 89 Represented as:

[0032]

[0033] Rock mass geomechanical classification system RMR 89 The following conversion relationship exists between the Geological Strength Index (GSI) and the Geological Strength Index (GSI):

[0034] RMR 89 =0.827GSI+15.394 (8)

[0035] Substituting formula (8) into formula (7) yields:

[0036]

[0037] Substituting formula (4) into formula (9), we can obtain the relationship between the rock mass deformation modulus and the P-wave velocity of sound waves as follows:

[0038] E rm =E i exp(0.274v a-p -2.227) (10)

[0039] The average wave velocity v of the rock mass within the original rock area a-p0 Combining the above formula (10), the rock mass deformation modulus E of the original rock area is expressed by the following formula. rm0

[0040] E rm0 =E i exp(0.274v a-p0 -2.227) (11)

[0041] Combining formulas (10) and (11), we get:

[0042]

[0043] Substituting formula (12) into formula (6), the quantitative relationship between the disturbance factor D and the P-wave velocity of the rock mass can be obtained as follows:

[0044]

[0045] Combining the wave velocity test results in Step 1 and Formula (13), the disturbance factor D at different depths can be estimated using the P-wave velocity of sound waves. It should be noted that since the range of the disturbance factor D is 0 to 1, if the result calculated by Formula (13) is greater than 1, it is taken as 1, and if it is less than 0, it is taken as 0.

[0046] A quantitative evaluation method for the rockburst tendency of surrounding rock under multiple disturbances; the specific method of Step 3 is as follows:

[0047] (1) According to the disturbance factor D at different depths obtained in Step 3, the area where the disturbance factor D = 1 is regarded as the highly damaged zone (HDZ), and the distribution depth is denoted as h HDZ (m); for the area where 1 < D < 0, it is divided into the weakly damaged zone (WDZ), and the distribution depth is denoted as h WDZ (m).

[0048] (2) By summarizing the distribution law of the disturbance factor D at different depths inside the surrounding rock of a large number of deep rock engineering projects, the continuous functions describing the change of the disturbance factor D with depth can be divided into two categories:

[0049] The first category, when there is a highly damaged zone in the surrounding rock (i.e., h HDZ > 0), the change trend of the disturbance factor D can be expressed as:

[0050]

[0051] In the formula, d is the distance from the excavation contour surface, in m.

[0052] The second category, when there is no highly damaged zone in the surrounding rock (i.e., h HDZ = 0), the change trend of the disturbance factor D can be expressed as:

[0053]

[0054] In the formula, D s is the disturbance factor at the excavation contour, and D s ≤ 1.

[0055] Then Formula (14) and Formula (15) are the continuous functions representing the change trend of D.

[0056] A quantitative evaluation method for the rockburst tendency of surrounding rock under multiple disturbances; the specific method of Step 4 is as follows:

[0057] (1) The rock elastic modulus E i can be obtained from Formula (9) as:

[0058]

[0059] According to the research of Hoek and Diederichs, the rock mass deformation modulus E rm It can be estimated using the perturbation factor D and GSI, i.e.:

[0060]

[0061] Substituting formula (17) into formula (16), the rock elastic modulus E i The relationship between the geological strength index GSI and the disturbance factor D is expressed as follows:

[0062]

[0063] The elastic modulus E was obtained from 200 sets of rock tests. i With residual elastic energy A EF Linear fitting of data, rock elastic modulus and residual elastic energy A EF (kJ / m) has the following empirical relationship:

[0064] A EF =6.8059E i +46.5610 (19)

[0065] Substituting formula (18) into formula (19), the residual elastic energy of the surrounding rock, characterized by the geological strength index GSI and the disturbance factor D, can be obtained. for:

[0066]

[0067] Based on the above formula, the residual elastic energy of the surrounding rock can be obtained by acquiring the geological strength index GSI and the disturbance factor D.

[0068] (2) Substituting the geological strength index GSI calculated in step 2 and the continuous function of the disturbance factor D obtained in step 3 into formula (20) yields the residual elastic energy of the surrounding rock that varies continuously with depth. According to the research of Gong Fengqiang et al., the criterion for judging rockburst tendency based on residual elastic energy is as follows:

[0069]

[0070] Combining formula (21) and the residual elastic energy of the surrounding rock This allows for a quantitative evaluation of the rockburst tendency of the surrounding rock at different depths.

[0071] Beneficial effects:

[0072] (1) The quantitative evaluation method for the rockburst tendency of surrounding rock under multiple disturbances provided by this invention proposes the following quantitative evaluation formula for the rockburst tendency of surrounding rock:

[0073]

[0074] The residual elastic energy A of the surrounding rock was calculated using the surrounding rock geological strength index GSI and the disturbance factor D. EF ,

[0075] This method overcomes the limitations of traditional rockburst tendency analysis, which is only applicable to the rock scale and difficult to directly apply to the engineering surrounding rock scale. It enables effective quantitative estimation of the residual elastic energy of the surrounding rock through the following formula:

[0076]

[0077] This method is used to assess the rockburst tendency of surrounding rock. It solves the problem that the rockburst tendency of surrounding rock may change due to excavation disturbance. Existing rockburst tendency judgments do not consider the rock mass structure and disturbance conditions. This method can accurately assess the rockburst tendency of surrounding rock under multiple disturbances. The results of the test are effective and can be better applied to actual engineering.

[0078] (2) The quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances provided by the present invention adopts the above-mentioned quantitative evaluation formula for the tendency of surrounding rock to burst in the steps, which takes into account both the rock mass structure effect, which is reflected in the geological strength index GSI, and the excavation disturbance effect (characterized by the disturbance factor D), which is in line with the actual situation of the engineering construction process and has strong practicality.

[0079] (3) The rock burst tendency evaluation method of surrounding rock under multiple disturbances proposed in this invention can be realized entirely by acoustic test data. The method described in this invention can not only evaluate the rock burst tendency of the surrounding rock after each excavation, but also obtain the evaluation results of the rock burst tendency of the surrounding rock after multiple disturbances after a limited number of acoustic tests, which can be used as a reference for the rock burst tendency of the surrounding rock in the subsequent excavation process. It is simple to operate, highly flexible, low in evaluation cost, and has great economic benefits. Attached Figure Description

[0080] Figure 1 This is a flowchart of the method of the present invention;

[0081] Figure 2 This is a diagram showing the blasting excavation advance and acoustic borehole layout in an embodiment of the present invention;

[0082] Figure 3 This is a graph showing the sound wave velocity data measured after each blast in an embodiment of the present invention;

[0083] Figure 4 This is an estimation diagram of the disturbance factor D at different depths of the surrounding rock after each blast in an embodiment of the present invention;

[0084] Figure 5 The elastic modulus E of this invention iIts residual elasticity index A EF relation;

[0085] Figure 6 This is a schematic diagram of the change in the residual elastic energy of the surrounding rock at different depths after each blast in an embodiment of the present invention, and a distribution diagram of the rockburst tendency.

[0086] Figure 7 This refers to the distribution depth of the EDZ, HDZ, and WDZ of the surrounding rock excavation damage zone after different blasting cycles in the embodiments of the present invention, as well as a function describing the continuous change of the disturbance factor D.

[0087] Figure 8 This represents the distribution range of rockburst tendency of the surrounding rock after different numbers of blasts in the embodiments of the present invention. Detailed Implementation

[0088] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0089] This invention provides a quantitative evaluation method for the rockburst tendency of surrounding rock under multiple disturbances.

[0090] Step 1: Conduct acoustic wave testing according to national standards (GB 50021-2001(2009) Code for Geotechnical Engineering Investigation, etc.) or industry standards (such as SL / T 264-2020 Code for Rock Testing in Water Conservancy and Hydropower Engineering, etc.); based on the fact that the P-wave velocity in the excavated damaged area is significantly lower than that in the original rock area, the depth of the low-velocity zone is regarded as the distribution depth h of the EDZ in the excavated damaged area. EDZ (m), areas with relatively stable wave velocity changes are considered as the original rock zone, and the average wave velocity within the original rock zone is taken as the average wave velocity v of the rock mass in the original rock zone. a-p0 (km / s).

[0091] Specifically, in this embodiment, after the first blast, based on experience, a 3.5m deep acoustic test hole was set at a distance of 1.5m from the top of the working face. A single-hole acoustic wave tester was used for acoustic wave testing. The transducer probe of the instrument moved from the bottom of the hole to the opening every 0.25m and measured the P-wave velocity of the rock mass. The measured acoustic wave data are as follows: Figure 2 As shown; according to Figure 2 The acoustic velocity distribution shows that the wave velocity within 3.5m is significantly lower than that at 3.5m. Therefore, the excavation damage zone EDZ can be determined to be h. EDZ=3.5m, beyond which lies the original rock zone. The average wave velocity in the original rock zone is taken as v. a-p0 = 5.75 km / s.

[0092] Step 2: Based on the Rock Mass Geomechanical Classification System (RMR) 76 Seismic wave P-wave velocity V with rock mass s-p (km / s) has the following quantitative relationship:

[0093]

[0094] Based on test results from multiple large-scale rock engineering projects, the following linear relationship exists between seismic wave and acoustic P-wave velocities (correlation coefficient can reach 0.97):

[0095] V s-p =0.893v a-p +0.151 (2)

[0096] Substituting formula (2) into formula (1), we get:

[0097] RMR 76 =11.907v a-p +5.347 (3)

[0098] According to GSI=RMR 76 Therefore, according to formula (3), GSI can be expressed as:

[0099] GSI = 11.907v a-p +5.347 (4)

[0100] The wave velocity in the original rock zone determined in step 1 is v a-p0 Then the GSI of the surrounding rock is:

[0101] GSI = 11.907v a-p0 +5.347 (5)

[0102] The geological strength index (GSI) of the surrounding rock can be quantitatively estimated using formula (5).

[0103] Based on the deformation modulus E of the rock mass rm (GPa) and the deformation modulus E of the original rock mass rm0 The ratio of (GPa) can be expressed as:

[0104]

[0105] In the formula, D is the disturbance factor, which can be used to characterize the degree of disturbance of the surrounding rock caused by blasting and unloading. The disturbance factor of the excavated damaged zone is 1≤D<0, and the original rock zone is D=0. In the Hoek-Brown guidelines of 2002 and 2018, only a few qualitative descriptions are given to determine the disturbance factor D, and no quantitative estimation method is given, which is difficult to apply to actual engineering.

[0106] Based on the rock mass deformation modulus E rm Available rock elastic modulus E i (GPa) and RMR 89 Represented as:

[0107]

[0108] RMR 89 The following transformation relationship exists between GSI and GSI:

[0109] RMR 89 =0.827GSI+15.394 (8)

[0110] Substituting formula (8) into formula (7) yields:

[0111]

[0112] Substituting formula (4) into formula (9), we can obtain the relationship between the rock mass deformation modulus and the P-wave velocity of sound waves as follows:

[0113] E rm =E i exp(0.274v a-p -2.227) (10)

[0114] Wave velocity v from the original rock area a-p0 Combined with formula (10), the deformation modulus E of the original rock mass is... rm0 It can be represented as:

[0115] E rm0 =E i exp(0.274v a-p0 -2.227) (11)

[0116] Combining formulas (10) and (11), we get:

[0117]

[0118] Substituting formula (12) into formula (6), the quantitative relationship between the disturbance factor D and the P-wave velocity of the rock mass can be obtained as follows:

[0119]

[0120] Combining the wave velocity test results in Step 1 and Formula (13), the disturbance factor D at different depths can be estimated using the P-wave velocity of the acoustic wave. It should be noted that since the range of D is 0 to 1, if the result calculated by Formula (13) is greater than 1, it is taken as 1, and if it is less than 0, it is taken as 0.

[0121] As Figure 3 shown: from the average wave velocity v a-p0 = 5.75 km / s in the original rock area and Formula (5), the geological strength index GSI of the surrounding rock can be obtained as 73.8; substituting the wave velocity measured in Step 1 ( Figure 2 ) into Formula (13), the disturbance factor D at different depths can be obtained.

[0122] Step 3: Based on the disturbance factor D at different depths in Step 2, the excavation damage area of the surrounding rock is divided into: a highly damaged area and a weakly damaged area;

[0123] According to the obtained disturbance factor D at different depths, the area with D = 1 is regarded as the highly damaged area HDZ, and the distribution depth is expressed as h HDZ (m); for the area where 1 < D < 0, it is divided into the weakly damaged area WDZ, and the distribution depth is expressed as h WDZ (m).

[0124] By summarizing the distribution law of the disturbance factor D of a large number of deep rock engineering at different depths inside the surrounding rock, the continuous functions describing the change of D with depth can be divided into two categories:

[0125] First category, when there is a highly damaged area in the surrounding rock (i.e., h HDZ > 0), the change trend of the disturbance factor D can be expressed as:

[0126]

[0127] In the formula, d is the distance from the excavation contour surface, in m.

[0128] Second category, when there is no highly damaged area in the surrounding rock (i.e., h HDZ = 0), the change trend of the disturbance factor D can be expressed as:

[0129]

[0130] In the formula, D s is the disturbance factor at the excavation contour, and D s ≤1.

[0131] Then Formula (14) and Formula (15) are the continuous functions representing the change trend of D;

[0132] As Figure 3As shown: the distribution of the disturbance factor D after the first blasting. The area where D = 1 is divided into a highly damaged zone HDZ, and its distribution depth h HDZ = 0 m. The area where 1 < D < 0 is divided into a highly damaged zone HDZ, and its distribution depth h WDZ = 3.5 m. Since there is no highly damaged zone (h HDZ = 0 m) after the first blasting, the change trend of the disturbance factor D belongs to the second type. According to formula (15), the change trend of the disturbance factor D is listed in Figure 7 as follows:

[0133]

[0134] Step 4: Calculate the remaining elastic energy A of the surrounding rock according to the continuous change function of the geological strength index GSI and the disturbance factor D EF , and evaluate the rockburst tendency of the surrounding rock through the remaining elastic energy A EF of the surrounding rock;

[0135] The rock elastic modulus E can be obtained from formula (9) i as:

[0136]

[0137] According to the research of Hoek and Diederichs, the rock mass deformation modulus E rm can be estimated by the disturbance factor D and GSI, that is:

[0138]

[0139] Substituting formula (17) into formula (16), the relationship between the rock elastic modulus E i and GSI and D can be obtained as:

[0140] <o:p>< / o:p>

[0141] As Figure 5 shown: Through the linear fitting of the elastic modulus E i and the remaining elastic energy A EF data in 2 * 100 sets of rock test results, there is the following empirical relationship between the rock elastic modulus and the remaining elastic energy A EF ]](kJ / m):

[0142]

[0141] A EF = 6.8059E i + 46.5610 (19)

[0143] Substituting formula (18) into formula (19), the remaining elastic energy A E r F m of the surrounding rock characterized by GSI and D can be obtained as:

[0144]

[0145] As can be seen from formula (20), the residual elastic energy of the surrounding rock can be obtained based on the GSI and D of the surrounding rock.

[0146] (2) Substituting the GSI calculated in step 2 and the continuous function of the disturbance factor D obtained in step 3 into formula (20) yields the residual elastic energy of the surrounding rock that varies continuously with depth. The criteria for determining rockburst tendency based on residual elastic energy are as follows:

[0147]

[0148] Combining formula (21) and the residual elastic energy of the surrounding rock This allows for a quantitative evaluation of the rockburst tendency of the surrounding rock at different depths.

[0149] like Figure 6 As shown: Based on the obtained GSI = 73.8 and the function formula (22) of the perturbation factor D, the residual elastic energy varying with depth can be obtained by substituting it into formula (20). like Figure 4 As shown; combined with different depths Based on formula (21), the rockburst tendency of the surrounding rock at different depths after the first blast can be evaluated. The depth ranges corresponding to different intensities of rockburst tendency are listed below. Figure 8 middle.

[0150] Step 5: After each excavation advance at the working face, repeat steps 1-5 to assess the rockburst tendency of the surrounding rock until the distribution characteristics of the rockburst tendency no longer change significantly. The evaluation result at this time can be regarded as the stable rockburst tendency of the surrounding rock after multiple disturbances.

[0151] Specifically, in this embodiment, acoustic wave tests were performed on the surrounding rock after the second, third, fourth, and fifth blasts, repeating steps 1 to 4 above; the acoustic wave data after each blast are as follows: Figure 2 As shown, the variation function of the disturbance factor D determined according to formula (13) is listed in... Figure 7 In formula (20), the residual elastic energy as a function of depth after each blast can be obtained by substituting GSI = 73.8 and the variation function of the perturbation factor D into formula (20). See Figure 5 As shown, the ranges corresponding to different intensities of rockburst tendency calculated in this way are listed in Figure 8 From Figure 5As can be seen, the distribution characteristics of rockburst tendency of the surrounding rock basically did not change after the fourth and fifth blasts. Therefore, the evaluation results of rockburst tendency of the surrounding rock after the fifth blast can be regarded as the stable rockburst tendency of the surrounding rock after multiple disturbances.

[0152] Thus, a quantitative evaluation of the rockburst tendency of the surrounding rock after multiple disturbances in a roadway at a depth of 1500m in a deep mine, as described in this embodiment, has been achieved. The evaluation results are as follows: Figure 5 and Figure 8 .

[0153] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances, characterized in that, The steps are as follows: Step 1: Conduct acoustic wave testing on the surrounding rock to measure the P-wave velocity at different depths from the excavation profile; obtain the depth h of the excavation damage zone distribution. EDZ The original rock zone; the average wave velocity v of the rock mass within the original rock zone. a-p0 ; Step 2: Utilize the average wave velocity v of the original rock mass in Step 1. a-p0 Calculate the geological strength index (GSI); determine the disturbance factor (D) at different depths; Disturbance factor D and rock mass acoustic wave P-wave velocity v a-p The quantitative relationship between them is as follows: ； Step 3: Based on the disturbance factor D at different depths in Step 2, the excavation damage zone of the surrounding rock is divided into: high damage zone and weak damage zone; Calculate the distribution depth of the highly damaged zone and the weakly damaged zone to obtain a function describing the continuous variation of the disturbance factor D in the surrounding rock with increasing depth; Step 4: Calculate the residual elastic energy A of the surrounding rock based on the continuous variation function of the geological strength index GSI and the disturbance factor D obtained in Step 2. EF Through the residual elastic energy A of the surrounding rock EF Evaluate the rockburst tendency of the surrounding rock; Step 5: Keep the acoustic test points in the surrounding rock unchanged. Repeat steps 1-4 after each excavation advance at the working face to assess the rockburst tendency of the surrounding rock until the distribution characteristics of the rockburst tendency no longer change significantly. The evaluation result at this time can be regarded as the rockburst tendency of the surrounding rock that no longer changes after multiple disturbances, and can be used as the long-term evaluation result of the rockburst tendency of the surrounding rock during subsequent excavation.

2. The quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances as described in claim 1, characterized in that, In step 1, the region with a stable P-wave velocity is considered the original rock zone; the region with a P-wave velocity lower than that of the original rock zone is considered the excavation damage zone; the distribution depth of the EDZ in the excavation damage zone is h. EDZ Its unit is m; The average wave velocity within the original rock zone is taken as the average wave velocity v of the rock mass in the original rock zone. a-p0 Its unit is km / s.

3. The method for quantitatively evaluating the tendency of surrounding rock to burst under multiple disturbances as described in claim 1, characterized in that, The steps in step 2 are as follows: (1) Establishing a rock mass geomechanical classification system RMR 76 With seismic P-wave velocity V s-p The quantitative relationship, V s-p The unit is km / s, and it is expressed as follows: ； (1) Seismic P-wave velocity V in multiple engineering rock masses s-p With the velocity v of sound wave P a-p The linear fitting results show that the two have the following linear relationship: ； (2) Substituting formula (2) into formula (1), we get: ； (3) Geological strength index GSI=RMR 76 In formula (3), GSI can be expressed as: ； (4) The average wave velocity v of the rock mass within the original rock zone determined in step 1. a-p0 The geological strength index (GSI) of the surrounding rock is expressed as follows: ； (5) The geological strength index (GSI) of the surrounding rock can be quantitatively calculated using the above formula (5); (2) Deformation modulus E of the rock mass rm Deformation modulus E of the original rock mass rm0 For example, it can be expressed as follows: ； (6) E rm and E rm0 The unit is GPa; In the formula, D is the disturbance factor, and the value of D ranges from 0 to 1. The larger the value of D, the more severe the disturbance to the surrounding rock. Rock mass deformation modulus E rm Available rock elastic modulus E i Rock mass geomechanical classification system RMR 89 Represented as: ； (7) E i The unit is GPa; Rock mass geomechanical classification system RMR 89 The conversion relationship between the geological strength index (GSI) and the geological strength index is expressed as follows: ； (8) Substituting formula (8) into formula (7), we get: ； (9) Substituting formula (4) into formula (9) yields the rock mass deformation modulus E. rm With the velocity v of sound wave P a-p The relational expression is as follows: ； (10) The average wave velocity v of the rock mass within the original rock area a-p0 Combining the above formula (10), the rock mass deformation modulus E of the original rock area is expressed by the following formula. rm0 : ； (11) Combining formulas (10) and (11), we get: ； (12) Substituting formula (12) into formula (6), the quantitative relationship between the disturbance factor D and the P-wave velocity of the rock mass acoustic wave is as follows: ； (13) Based on the measured P-wave velocity of the acoustic wave at different depths from the excavation profile, the disturbance factor D at different depths is calculated using formula (13).

4. A quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances, as described in claim 1 or 3, characterized in that, The method for step 3 is as follows: (1) Based on the perturbation factor D at different depths obtained in step 2, The region with D=1 is considered a high-damage zone (HDZ), and its distribution depth is represented by h. HDZ Its unit is m; For the region where 1 < D < 0, it is divided into a weak damage zone WDZ, and the distribution depth is expressed as h WDZ , with the unit of m; (2) The continuous functions of the disturbance factor D at different depths as a function of depth are divided into the following two categories: The first type, when h HDZ A value greater than 0 indicates the presence of a highly damaged zone in the surrounding rock. The trend of the disturbance factor D is described as follows: ； (14) In the formula, d is the distance from the excavation outline, and its unit is m; The second category, when h HDZ =0 means that there is no highly damaged zone in the surrounding rock. The trend of the disturbance factor D is expressed as follows: ； (15) In the formula, D s D is the disturbance factor at the excavation outline. s ≤1.

5. A quantitative evaluation method for the tendency of surrounding rock to burst under multiple disturbances, as described in claim 1 or 3, characterized in that, Step 4 is as follows: (1) The elastic modulus E of the rock can be obtained from formula (9). i for: ； (16) Rock mass deformation modulus E rm The following formula is used to calculate the results using the perturbation factor D and the geological strength index GSI: ； (17) Substituting formula (17) into formula (16), the rock elastic modulus E i The relationship between the geological strength index GSI and the disturbance factor D is expressed as follows: ； (18) Through the rock elastic modulus E i With residual elastic energy A EF The relationship is as follows: ； (19) A EF The unit is kJ / m 3 ; Substituting formula (18) into formula (19), the residual elastic energy of the surrounding rock, characterized by the geological strength index GSI and the disturbance factor D, is obtained. for: ； (20) (2) Substitute the continuous functions of the geological strength index GSI and the disturbance factor D into formula (20) to obtain the residual elastic energy of the surrounding rock that varies continuously with depth. ; The criteria for determining rockburst tendency based on residual elastic energy are as follows: ； (21) Combining formula (21) and the residual elastic energy of the surrounding rock This allows for a quantitative evaluation of the rockburst tendency of the surrounding rock at different depths.

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