Roadway anti-seismic safety factor calculation method and safety prediction method

Abstract

The application discloses a kind of roadway anti-seismic safety factor calculation method and safety prediction method, step 1, the minimum mine shock energy E that roadway can resist is determined by all blasting microseismic data in pit min ; Step 2, according to the propagation attenuation law of vibration wave in rock mass, the maximum mine shock energy E max That can be expected to occur is calculated from any position to the remaining energy E m Of roadway;Step 3, according to the minimum mine shock energy E min And E m Resisted by roadway, the anti-seismic safety factor β of roadway is calculated. Wherein, the physical meaning of roadway anti-seismic safety factor calculation formula involved is clear, the parameter calculation involved in formula is clear, the acquisition of blasting microseismic data involved in the calculation process is relatively simple, the cost is very low, and it is strong in universality.

Description

Technical Field

[0001] This invention relates to a method for calculating the seismic safety factor of roadways and a method for predicting safety. Background Technology

[0002] Mine tremors are rapid displacements and fracturing of the surrounding rock during underground coal mining. They are a response of the coal and rock mass to regional or localized stress adjustments, accompanied by energy generation. Mine tremors occur frequently during coal mining and can potentially generate rockbursts (a type of disastrous mine tremor), posing a significant threat to the safety of roadways. Therefore, determining the seismic resistance of roadways is an essential task in working face design, stop line design, support design, and advance speed arrangement.

[0003] However, existing methods for calculating seismic resistance generally only add the seismic energy of anchor bolts and anchor cables together. While this can reflect the seismic resistance of the roadway to some extent through the anchoring level, it does not analyze the impact of the surrounding environment on the seismic energy of the mine. This not only results in large calculation errors but also seriously affects subsequent workface design, stop-mining line design, support design, and advance speed arrangement. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for calculating the seismic safety factor and predicting the safety of roadways. Based on microseismic monitoring parameters and the propagation and attenuation laws of seismic energy in rock mass, the method calculates the seismic safety factor and predicts the safety of roadways, which has very high practical value and significance.

[0005] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0006] A method for calculating the seismic safety factor of a tunnel includes the following steps:

[0007] Step 1: Determine the minimum mine seismic energy E that the roadway can withstand by using all underground blasting microseismic data. min ;

[0008] Step 2: Calculate the maximum expected seismic energy E based on the propagation and attenuation law of seismic waves in the rock mass. max The remaining energy E propagating from any location into the tunnel m ;

[0009] Step 3: Based on the minimum seismic energy E that the tunnel can withstand. min and E m The seismic safety factor β of the roadway was calculated as follows:

[0010] β=E min / E m

[0011] Preferably, in step 1, all blasting microseismic data E within the downhole monitoring area are statistically analyzed. i To obtain the maximum seismic energy value max{E i Based on the principle of least adverse safety, it is set as the minimum seismic energy E that the roadway can withstand. min .

[0012] Preferably, in step 2:

[0013] Step 201: Select microseismic events in the monitoring area, and calculate the propagation absorption coefficient of the seismic wave in the rock mass based on the propagation attenuation law of peak particle velocity in the rock mass.

[0014] Step 202: Based on the propagation absorption coefficient Calculate the propagation and attenuation law of seismic wave energy in rock mass.

[0015] Preferably, in step 201, the propagation absorption coefficient The following formula is used for least squares fitting calculation to obtain the result:

[0016]

[0017] In the formula, c is a proportionality constant. r is the propagation absorption coefficient. i Let A be the distance from the seismic source to sensor i. i Let be the peak velocity of the particle recorded by sensor i, and e be the natural constant.

[0018] Preferably, in step 202, the formula for the attenuation of seismic wave energy propagation in the rock mass is:

[0019]

[0020] In the formula, r0 represents the rupture radius of the seismic source, r represents the distance from the seismic source to the roadway, E0 is the seismic energy of the seismic source, and E r Let e ​​be the residual energy propagated from the earthquake source to the tunnel, and e be the natural constant.

[0021] Preferably, the maximum expected seismic energy E max The following formula is used for calculation:

[0022] E max =10 a / b

[0023] In the formula, a and b are statistical constants in the Gutenberg formula, and satisfy:

[0024] lgN(≥lgE)=a-blgE

[0025] In the formula, E is the microseismic energy; N≥lgE and N is the number of microseisms with energy greater than or equal to E; a represents the level of microseismic activity, and b represents the proportional relationship between the number of microseisms of different sizes.

[0026] Preferably, the maximum expected seismic energy E max The remaining energy E propagating from any location into the tunnel m The following formula is used for calculation:

[0027]

[0028] In the formula, r0 represents the rupture radius of the seismic source, r represents the distance from the seismic source to the roadway, and e is the natural constant. This is the propagation absorption coefficient.

[0029] Preferably, the rupture radius r0 of the seismic source is calculated using the following formula:

[0030]

[0031] In the formula, k is a coefficient; v s f is the transverse wave velocity. c The corner frequency.

[0032] Preferably, the corner frequency f c The following formula is used for calculation:

[0033]

[0034] In the formula, D(f) is the displacement spectrum of the vibration waveform; V(f) is the velocity spectrum of the vibration waveform.

[0035] A method for predicting the seismic safety of roadways, wherein the seismic safety factor β of the roadway is calculated using any of the above-mentioned methods, and the distance r value corresponding to when β is less than 1 is predicted as the area of ​​the roadway threatened by mine earthquake.

[0036] The beneficial effects of this invention are:

[0037] This invention relates to a method for calculating the seismic safety factor of roadways based on microseismic monitoring parameters. First, it determines the minimum mine-induced seismic energy E that the roadway can withstand using all underground blasting microseismic data. min Then, based on the attenuation law of seismic waves in the rock mass and the minimum seismic energy that the roadway can resist, the seismic safety factor β of the roadway is calculated. Subsequently, the area threatened by seismic tremors in the roadway can be predicted based on the seismic safety factor. Among them, the physical meaning of the formula for calculating the seismic safety factor of the roadway is clear, the parameters involved in the formula are clearly calculated, the acquisition of blasting micro-seismic data involved in the calculation process is relatively simple, the investment cost is very low, and it has strong universality.

[0038] Furthermore, the minimum seismic energy that the roadway can withstand according to this invention is highly timely and can be updated in real time with the microseismic data obtained from monitoring. This invention has conducted in-depth research on the propagation and attenuation laws of seismic waves in rock strata, has good operability and reliability, can predict the threat areas of roadways, effectively reduce the probability of safety accidents, and has very important practical value and significance. Attached Figure Description

[0039] Figure 1 This is a spatial distribution diagram of blasting microseismic events according to an embodiment of the present invention;

[0040] Figure 2 This is an absorption coefficient fitting diagram of the method for calculating the seismic safety factor of roadways based on microseismic monitoring in an embodiment of the present invention;

[0041] Figure 3 These are fitting graphs a and b of the method for calculating the seismic safety factor of roadways based on microseismic monitoring in an embodiment of the present invention.

[0042] Figure 4 This is a distribution diagram of the seismic safety factor of the tunnel along the tunnel distance in an embodiment of the present invention. Detailed Implementation

[0043] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0044] A method for calculating the seismic safety factor of a tunnel includes the following steps:

[0045] Step 1: Determine the minimum mine seismic energy E that the roadway can withstand by using all underground blasting microseismic data. min Preferred:

[0046] Statistical analysis of all blasting microseismic data E within the downhole monitoring area i To obtain the maximum seismic energy value max{E i Based on the principle of least adverse safety, it is set as the minimum seismic energy E that the roadway can withstand. min Microseisms refer to tiny vibrations caused by rock fracturing or fluid disturbance, with magnitudes generally between -2 and 2.

[0047] Step 2: Calculate the maximum expected seismic energy E based on the propagation and attenuation law of seismic waves in the rock mass. max The remaining energy E propagating from any location into the tunnel m Preferred:

[0048] First, microseismic events in the monitoring area were selected. Based on the propagation attenuation law of peak particle velocity in the rock mass, the propagation absorption coefficient of the seismic wave in the rock mass was calculated. For example, the propagation absorption coefficient The following formula can be used to perform least squares fitting calculations to obtain the result:

[0049]

[0050] In the formula, c is a proportionality constant. r is the propagation absorption coefficient. i Let A be the distance from the seismic source to sensor i. i Let be the peak velocity of the particle recorded by sensor i, and e be the natural constant.

[0051] Secondly, based on the propagation absorption coefficient The propagation attenuation law of seismic wave energy in rock mass is calculated, where the formula for the propagation attenuation of seismic wave energy in rock mass is:

[0052]

[0053] In the formula, r0 represents the rupture radius of the seismic source, r represents the distance from the seismic source to the roadway, E0 is the seismic energy of the seismic source, and E r Let e ​​be the residual energy propagated from the earthquake source to the tunnel, and e be the natural constant.

[0054] Preferably, the rupture radius r0 of the seismic source is calculated using the following formula:

[0055]

[0056] In the formula, k is a coefficient, which can be taken as 0.21; v s The transverse wave velocity is typically taken as 2300 m / s, f c The corner frequency.

[0057] Preferably, the corner frequency f c The following formula is used for calculation:

[0058]

[0059] In the formula, D(f) is the displacement spectrum of the vibration waveform; V(f) is the velocity spectrum of the vibration waveform.

[0060] Then, based on the formula for the propagation and attenuation of seismic wave energy in the rock mass, the maximum expected seismic energy E is calculated. max The remaining energy Em propagating from any location into the tunnel can be calculated, for example, using the following formula:

[0061]

[0062] In the formula, r0 represents the rupture radius of the seismic source, r represents the distance from the seismic source to the roadway, and e is the natural constant. This is the propagation absorption coefficient.

[0063] Among them, the maximum expected seismic energy E max The following formula can be used for calculation:

[0064] E max =10 a / b

[0065] In the formula, a and b are statistical constants in the Gutenberg formula, and satisfy:

[0066] lgN(≥lgE)=a-blgE

[0067] In the formula, E is the microseismic energy; N≥lgE and N is the number of microseisms with energy greater than or equal to E; a and b are constants, whose statistical significance is as follows: a represents the level of microseismic activity, and b represents the proportional relationship between the number of microseisms of different sizes.

[0068] Step 3: Based on the minimum seismic energy E that the tunnel can withstand. min and E m The seismic safety factor β of the roadway was calculated as follows:

[0069] β=E min / E m

[0070] A method for predicting the seismic safety of roadways involves calculating the seismic safety factor β of the roadway using any of the methods described above, predicting the distance r value corresponding to when β is less than 1 as the area of ​​the roadway threatened by mine-induced seismic activity, that is, calculating and obtaining the distribution of the seismic safety factor of the roadway and its distance along the roadway, and then using the seismic safety factor of the roadway being less than 1 to predict the area of ​​the roadway threatened by mine-induced seismic activity.

[0071] This invention relates to a method for calculating the seismic safety factor of roadways and a method for predicting roadway seismic safety based on microseismic monitoring parameters. This method is applicable to the field of microseismic monitoring for mine safety. The following example analysis uses microseismic data from a coal mine over a period of time to determine the threatened area based on the distance *r* corresponding to a roadway seismic safety factor less than 1. The invention is implemented according to the following principles:

[0072] (1) Based on the statistical distribution of micro-vibration energy from a certain mine blasting, as follows: Figure 1 As shown, the microseismic energy distribution ranges from 99.77 to 9231.81 J, and the minimum seismic energy that the roadway can withstand is 9231.81 J.

[0073] (2) Statistical analysis of microseismic events in the mine, such as... Figure 2As shown, the propagation absorption coefficient of the seismic wave in the rock mass was obtained by fitting as 0.000363;

[0074] (3) The values ​​of a and b obtained by fitting microseismic events are 6.1900 and 1.0031, respectively. Figure 3 As shown, the maximum seismic energy is calculated to be 1.48E+06J, and then the remaining energy of the maximum seismic energy propagating from any location to the roadway is obtained.

[0075] (4) By analyzing the waveforms of historical strong mine earthquake events, the rupture radius of the mine source was calculated to be 33m-106m;

[0076] (5) Based on the remaining energy and the minimum seismic energy that the roadway can withstand, the distribution of the roadway's seismic safety factor along the roadway distance can be calculated as follows: Figure 4 As shown, the range of the mine earthquake threat area is from 400m around the roadway (rupture radius 33m) to 1000m around the roadway (rupture radius 106m).

[0077] Examples show that the parameter calculation process involved in this invention is clear and explicit, the results are also clear, it has good universality, is easy to operate, and has very low cost. It can enhance the monitoring of threatening areas in roadways and take targeted prevention and control measures, which can effectively reduce the probability of accidents.

[0078] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for calculating a seismic safety factor of a roadway, comprising the following steps: Step 1, determine the minimum mine shock energy E that the roadway can resist through all the downhole blasting microseismic data min ; Step 2, calculate the expected maximum mine shock energy E according to the propagation and attenuation law of seismic wave in rock mass max The residual energy E propagating to the roadway from any position m ; Step 3, according to the minimum seismic energy E that the roadway can resist min and E m The seismic safety factor β of the roadway is calculated: β = E min / E m ; In step 1, all the blasting microseismic data E in the monitored area is counted i , the maximum mine shock energy value max{E i} is obtained, and according to the principle of the most unfavorable safety, it is set as the minimum mine shock energy E min that the roadway can resist; In step 2: Step 201, selecting a microseismic event in a monitoring area, fitting and calculating a propagation absorption coefficient of a vibration wave in a rock mass according to a propagation attenuation law of a peak particle velocity in the rock mass Step 202, calculating the propagation absorption coefficient according to the propagation absorption coefficient The propagation attenuation law of the vibration wave energy in the rock mass is calculated. In step 201, the propagation absorption coefficient The least square fitting calculation is performed by using the following formula to obtain: where c is a proportionality constant, is the propagation absorption coefficient, r i is the distance from the source to sensor i, A i is the peak particle velocity recorded by sensor i, e is the natural constant; In step 202, the propagation and attenuation formula of seismic wave energy in rock mass is: where r0represents the rupture radius of the source, r represents the distance from the source to the roadway, E0is the vibration energy of the source, E r is the remaining energy of the source propagating to the roadway, and e is a natural constant. The maximum mine shock energy E that can occur is expected max The following formula is used for the calculation: E max ＝10 a / b In the formula, a and b are statistical constants in the Gutenberg formula, and satisfy: lgN=a-blgE In the formula, E is microseismic energy; N≥lgE and N is the number of microseisms with energy greater than or equal to E; a represents the microseismic activity level, and b represents the proportional relationship of different sizes of microseisms; The maximum mine shock energy E expected to occur max The residual energy E propagating to the roadway from any location m This is calculated using the following equation: In the formula, r0 represents a rupture radius of a seismic source, r represents a distance from the seismic source to a roadway, e is a natural constant, is a propagation absorption coefficient; The focal rupture radius r0 is calculated by the following formula: where k is a coefficient; v s is the shear wave velocity, f c is the corner frequency; Corner frequency f c The following formula is used for the calculation: In the formula, D(f) is the displacement spectrum of seismic wave, and V(f) is the velocity spectrum of seismic wave.

2. A method of predicting seismic safety of a roadway, characterized by, The seismic safety factor β of the roadway is calculated by the method for calculating a seismic safety factor of a roadway according to the above claim 1, and the distance r value corresponding to β less than 1 is predicted as the range of the area threatened by mine earthquake of the roadway.

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