KR100673552B1 - Method for reducing blasting vibrations by analyzing frequency features of the ground in a damaged region - Google Patents

Abstract

A method for reducing vibration generated on the ground of a damage-expected region due to blasting performed in mines, public work sites, and the like is provided. A delay time designing method for reducing blasting vibration by analyzing frequency features of the ground in a damaged region comprises: a test blasting step(10) for measuring reference waveform values that causes the highest vibration to be occurred on a damage-expected region; a step(11) of analyzing frequency values using the measured reference waveform values to calculate frequency features of the ground in the damage-expected region; a step(12) of obtaining a frequency that displays the highest vibration rate in the frequency features of the reference waveform values to obtain a cycle of the reference waveform values, and setting out a half integer frequency of the cycle as a delay time to determined a delay time capable of minimizing blasting vibration on the damage-expected region; a step(13) of determining a detonator to be used according to delay time characteristics of a detonator to be applied to a blasting job site; and a step(14) of designing an optimal delay time according to the detonator after the detonator determining step.

Description

Method for reducing blasting vibrations by analyzing frequency features of the ground in a damaged region}

1 is a flow chart of a general blasting design procedure,

2 is a block diagram showing a method for designing a blast vibration reduction delayed parallax through frequency analysis of a target ground according to the present invention;

3 is a measurement position diagram for obtaining a reference waveform that vibrates most significantly according to the change of rock quality in the area of concern due to blasting;

4A to 4C are lateral component, vertical component and tangential component waveforms of the blasting vibration measured in the region of concern due to the shock wave generated after the blasting in the blasting region.

Figures 5a and 5b is a frequency analysis of the reference waveform and the reference waveform selected by the present invention,

6A through 6C are modeling waveform diagrams in which the reference waveform and the vibration waveform of the attenuation delay time difference 0.5T overlap and attenuate.

7A and 7B are modeling waveform diagrams in which the reference waveform and the vibration waveforms of the amplification delay time difference 1.5T and 2.5T overlap and attenuate.

8A and 8B are modeling waveform diagrams in which the reference waveform and the vibration waveforms of the amplification delay parallaxes 1T and 2T overlap and are amplified;

9 is a delay parallax design diagram of a preferable two-row and eight-column blasting pattern using a primer having a delay time of 20 Hz.

<Description of Symbols for Main Parts of Drawings>

15: Transverse component 16: Vertical component

17: tangential component 18: reference waveform

20: 0.5T waveform 21: 1.5T waveform

22: 2.5T Waveform 23: 1T Waveform

24: 2T waveform

The present invention relates to a method for designing a delayed lag reduction method for blasting vibration reduction through frequency analysis of a target ground, and more specifically, to calculate a blasting vibration wave period by calculating the ground frequency of an area where blasting vibration is concerned. The method relates to a method of designing delay lags of each stage by considering the frequency characteristics of the ground of the target ground.

In general, the blasting vibration is increased in proportion to the explosive charge simultaneously, and the delayed primer having a small delay time is designed to control the blasting vibration. This delayed primer is a method of attenuating the ground vibration significantly compared to the simultaneous blasting which detonates the whole explosive at once and is still used in most blasting construction sites.

The method of estimating the amount of blast per allowable delay of blasting vibration is to measure the ground vibration caused by blasting according to the change of distance and the amount of load, and then statistically process (e.g., using the least-squares method) to include 95% of the data. The blast vibration propagation formula of the section is established to calculate and regulate the amount of charge per delay to perform the blasting construction below the specified permissible vibration for structures and livestock, etc. near the blasting construction area.

However, the method of using a primer with a predetermined delay time without considering the frequency of the affected area has an effect in a certain frequency band, but amplifies the vibration in a frequency band that matches or multiplies the vibration period of the ground. It acts as a factor to disperse the measured value of vibration when measuring blast vibration.

As a result, the blasting vibration propagation equations, which must include amplified vibrations due to delayed lags that coincide with or become multiples of the ground vibration cycle, result in excessive explosive charge regulation. Received frequent complaints from the residents of the surrounding area during the process of public photographs, there was a problem that excessive construction costs are inevitable due to the design change.

As a prior art for solving this problem, Korean Patent Laid-Open Publication No. 2005-0068674 discloses a blasting method for reducing vibration noise by mutually interfering blasting vibrations.

This prior art comprises the steps of: providing an ELCTRONIC DELAY DETONATOR comprising an I.C timer comprising an electrical energy storage capacitor, a delay element and a switching element powered by the same capacitor, and a forward generator primer; Measure the vibration wave of the blasting object in the field, and repeat the same vibration by repeating the triangular waveform appearing in the trigonometric function decaying at regular intervals by half a period. Inputting a numerical value in which the initial maximum amplitude is halved and the vibration is reduced in other parts compared to when there is no time difference while weakly synthesizing; And a correlation function of an optimal detonation time difference and an oscillation waveform in order to mutually reduce and mutually reduce vibration when blasting using the electronic delay unit. It is characterized by blasting.

Such a conventional technique is to reduce the blasting vibration through mutual interference by actively overlapping the vibrations in a plurality of vibration sources, and in particular, the best function of the detonation time difference is the mutual function of the vibration waveforms measured at the blasting objects in the field. The theoretical application using the blast can be applied.

However, since the blasting vibrations are reduced by mutually interfering blasting vibrations in the blasting holes themselves, the blasting vibrations that actually affect the damaged areas are not considered because they do not consider the nature of the vibration waveform that causes the greatest vibration in the ground of the damaged area. There was a problem that could not be reduced.

The present invention has been made to solve the above problems, an object of the present invention is to provide a method for reducing the vibration of the ground generated in the area of concern due to the blasting of mines, civil engineering works.

It is another object of the present invention to provide a method of calculating a frequency band that vibrates the area of greatest concern in accordance with the ground characteristics of the area of concern of blasting vibration damage and blasting the vibration frequency to be offset.

It is still another object of the present invention to provide a method of reducing ground vibration occurring in a region of concern by blasting a plurality of blasting holes with a time difference so that a frequency which gives the greatest vibration to the region of concern is offset by mutual interference. It is.

The blasting method according to the present invention includes a test blasting step for measuring a reference waveform giving the most vibration to a region of concern and a frequency analysis of the measured reference waveform to calculate frequency characteristics of the target ground of the region of concern; Obtain the frequency representing the largest oscillation speed in the frequency characteristic of the reference waveform and set the period of the reference waveform by the inverse, and set the integer multiple of 1/2 of the period as the delay time to minimize the blasting vibration for the area of concern. Determining a possible delay time difference; Determining a primer used according to a delayed parallax characteristic of a primer to be applied to a blasting site; After the use primer determination step is composed of the optimal delay parallax design stage according to the primer.

The reference waveform is characterized in that the component having the largest amplitude among the transverse component, the vertical component, and the tangential component of the elastic wave transmitted to the region of concern is selected as the reference waveform.

The test blasting step is characterized in that the waveform for the first ball or the last ball with a delay time of about 1,000㎳ (1 second) and the main blasting.

In the optimal delay time design step, the blast second time interval between the blast holes from the first column to the last column of the first row is 1/2 of the reference waveform period, and the blast second time of the first column of the second row is the first row. Delaying 1/2 of the reference waveform period from the blast seconds of the last column, and to the last column of the last row at the interval of blast seconds.

The blast second time interval between the blast holes from the first column to the last column of the first row is an integer multiple of 1/2 of the reference waveform period, and the blast second time of the first column of the second row is blasted in the last column of the first row. An integer multiple of 1/2 of the reference waveform period is delayed from the beginning time, and the last column is set to the last column at the blast second time interval.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

1 is a flow chart of a typical blasting design.

In the design process of FIG. 1 showing a general blasting design flow, the present invention is applied in a process related to blast pollution reduction measures, and can be applied in a blasting influence zone analysis process.

That is, the present invention is completed by the application of the measurement management system by the blast vibration reduction delay time difference design method of FIG. 2 by the necessity of the blast pollution reduction countermeasure of FIG.

2 is a block diagram showing a method for designing a blasting vibration reduction delayed parallax through frequency analysis of a target ground according to the present invention.

The blasting vibration reduction delay time difference determination method according to the present invention includes a test blasting step (10) for measuring a reference waveform that gives the most vibration to the area of concern; Frequency analysis of the measured reference waveforms to calculate frequency characteristics of the target ground of the damage area of concern; Obtain the frequency representing the largest oscillation speed in the frequency characteristic of the reference waveform and set the period of the reference waveform by the inverse, and set the integer multiple of 1/2 of the period as the delay time to minimize the blasting vibration for the area of concern. Determining a possible delay time difference (12); Determining a used primer according to a delayed parallax characteristic of a primer to be applied to a blasting site; After the use primer determination step is composed of the optimum delay time difference design step 14 according to the primer.

Step 10 for obtaining the reference waveform is obtained from the vibration recording of the main blasting, in which the waveform of the single hole is used as the waveform for the first ball or the last ball with a delay difference of about 1,000 ms (one second). This method is adopted as a method for monitoring the frequency change according to the distance change of the target point and the blasting place.

When explosives explode in a charge hole, an initial impact detonation pressure (or impact pressure), a delayed explosive gas pressure due to the combustion of a gunpowder, and a high temperature of 3,000 ° C. or more are generated.

The shock wave due to the shock pressure propagated in the three-dimensional area from the blasting area is attenuated significantly according to the distance, and 0.5 to 20% of the energy due to the blast is propagated into the rock in the form of a seismic wave to generate vibration of the ground.

The process of test blasting to obtain a reference waveform that vibrates most greatly according to the change of rock quality in the area of concern is as shown in FIG. 3, for example, a certain distance (for example, 100 m, 150 m, etc.) from the blasting area A. Vibration measuring devices are installed in distant civil complaint areas (B, C) to measure blast vibration.

Blasting vibration can be divided into shock vibration and free vibration, and the free vibration that propagated first cooperates with the shock vibration of the next stage and cooperates, or the shock vibration propagated first and the next stage shock in the region of short time difference or low frequency. In coordination with vibrations, greater vibrations can be made.

4A to 4C show the lateral component, vertical component and tangential component waveforms of the blasting vibration measured in the region of concern due to the shock wave generated after the blasting in the blasting region in the time domain.

The vibration waveform of the test blast is an independent waveform which is not included in the measurement waveform of the present blast (from 0 second to 350 Hz) and is 0.63 seconds in the waveform of the transverse component of FIG. 4A showing the largest vibration velocity among the three components. Frequency analysis is performed by selecting the vibration waveform of the test blast lasting from 0 to 0.7 seconds as a reference waveform.

As shown, the elastic wave of the blasting is transmitted for 0.35 seconds after blasting, and there is no vibration from 0.35 seconds to 0.63 seconds, and the vibration of the test blasting lasts from 0.63 seconds to 0.7 seconds.

Transverse components 15, vertical components 16 and tangential components 17 of the acoustic wave transmitted to the area of concern are transmitted in three dimensions, among which the transverse components of the test blast vibration are shown in FIG. 4A. Since (15) has the largest amplitude and this transverse component 15 will do the most damage to the area of concern, the transverse component 15 of the test blast vibration is selected as the reference waveform.

The frequency analysis step 11 finds the first zero crossing point of the reference waveform and sets it as the origin, and analyzes the vibration waveform lasting for a predetermined time from the origin through high-speed pre-free transform.

5A and 5B show frequency analysis diagrams of the reference waveform and the reference waveform selected by the present invention.

As shown, the reference waveform 18 should be a single co-blasting waveform that includes both shock and free vibration. The reference waveform 18 used for modeling is measured at 33 m with a dose of 1 kg per blast hole.

In order to obtain the reference waveform 18 in this blasting, select a ball to be separated and select a primer having a delay delay of the extreme end of the blasting and a delay of about 300 kHz (for example, using LP primer 6 here). Load and detonate. The number of blast holes was 15 holes, and 14 primers with a delay time of 20 Hz and one primer for the reference waveform 18 were used.

The reference waveform 18 shown in FIG. 5A represents a section cut out of a section of about 100 Hz in the transverse component 15 of the vibration waveform by the test blasting in FIG. 4A including both the impact vibration portion and the free vibration portion. .

The frequency analysis diagram 19 shown in Fig. 5B is a waveform shown in the frequency domain by performing a Fast Fourier Transform (FFT) on the waveform of Fig. 5A.

The portion representing the maximum amplitude of the frequency analysis diagram 19 shown in the frequency domain is analyzed to have a main frequency of 110 Hz as the portion representing the maximum particle velocity of the reference waveform 18.

When the period T is obtained from the frequency, T = 1/110 = 0.009, s = 9 Hz, and T / 2 = 4.5 Hz.

Delay time determination step 12 may determine the delay time of 0.5T, 1T, 1.5T, 2T, 2.5T through the frequency of the reference waveform 18 calculated in the frequency analysis step by the parallax theory of Langefors.

Langefors' disparity theory is as follows (1).

...................(1)

...................(One)

Where τ is the delay time of the delayed primer, H is the constant, and T is the period of the blasting vibration.

6A to 6C show a modeling waveform diagram in which the reference waveform and the vibration waveform of the attenuation delay time difference 0.5T overlap and attenuate.

The reference waveform is shown in Fig. 6A, and as shown in Fig. 6B, when the blasting interval is blasted with a delay time of 0.5T, the reference waveform and the 0.5T delayed time difference oscillation waveform (indicated by dotted lines) overlap in the area of concern. Lose. The overlapping vibration waveforms cancel and cancel each other as shown in Fig. 6C.

The maximum velocity of the attenuated waveform is 4.95 mm / s as shown in Table 1, and has a maximum velocity corresponding to 72% compared to the reference waveform of 6.86 mm / s.

7A and 7B show modeling waveform diagrams for the reference waveform and amplification delay time differences 1.5T and 2.5T.

The waveforms shown are vibration waveforms measured at the area of concern when blasting is performed with a lag time of 1.5T and 2.5T. The maximum velocity of each waveform is 6.73 mm / s and 6.86 mm / s as shown in Table 1, and has a maximum velocity corresponding to 98% and 100% compared to the reference waveform 6.86 mm / s. In the attenuation delay time, it can be seen that the speed of the blasting vibration is attenuated or equal.

8A and 8B show modeling waveform diagrams for the reference waveform and the amplification delay time difference 1T and 2T.

The waveforms shown are vibration waveforms that are measured at the area of concern when blasting is performed with a delay time interval of 1T and 2T. The maximum velocity of each waveform is 10.54 mm / s and 7.75 mm / s as shown in Table 1, and has a maximum velocity corresponding to 154% and 113% compared to the reference waveform 6.86 mm / s. It can be seen that the speed of the blasting vibration is amplified in the amplification delay time difference.

Therefore, the damping of the vibration is best when the H value is 0.5, and the damping is achieved when it is a multiple of 0.5. When the H value is an integer, the vibration is amplified. In addition, when τ> 3T, there is no cooperation between different steps. Therefore, it can be assumed that cooperation between different steps does not occur when τ> 2.5T.

Maximum Vibration Rate Increase / Decrease Rate H  τ (㎳) PPV (mm / sec) (Rate of increase)% Reference Waveform 0.5 1 1.5 2 2.5 0 5 9 14 18 23 6.86 4.95 10.54 6.73 7.75 6.86 100 72 154 98 113 100

In addition, the time difference between 0.5T, 1.5T, 2.5T, which delays the blast vibration, and 1T, 2T, which delays the blast vibration, is shown in Table 2 below.

H τ (㎳) Reference waveform 0 Attenuation delay time difference 0.5 5 1.5 14 2.5 23 Amplification Delay One 9 2 18

Determining the use primer 13 is different from the delay time difference of the commercially available primers and should be determined according to the characteristics of the place of use. Therefore, based on the place of use and the delay time determined above, it is decided whether the use primer is a delayed electric primer, a non-electric primer, or an electron primer.

Commercially available primers can be divided into electric primers, non-electric primers and electronic primers according to their characteristics.

Electric primers and non-electrical primers are primers with unique delay lags of each primer. In the case of electric primers, a primer having a unique delay lag is used to arbitrarily delay electricity at a blasting machine. Multistage blasters are used to control the delay lag by sending them.

Non-electrical primers adjust the parallax between blast holes by combining a primer with an inherent delay in the blast hole with approximately five surface primers with another inherent delay at the surface outside the blast hole.

These primers are not very free in terms of the control of delayed parallax due to the use of inherent parallaxes.

On the other hand, the electron primer has a built-in IC circuit that determines the delay time, so that the delay time of the primer can be arbitrarily used in units of 1㎳, and the standard deviation of each step is 0.2㎳, which can realize ultra-precision time difference with almost no delay time error. It can be a primer.

Therefore, in order to realize the maximum effect of the present invention, the use of an electron primer is preferable. However, due to the high price of electron primers, the introduction of electron primers for blasting at general construction sites is uneconomical at present.

However, in the present invention, in consideration of the timing of generalization of the introduction of the electron primer, both the primer and the electron primer, which are generally used, are considered in the determination of the use primer.

Among the delayed delays calculated in the delay determination step (12), the attenuation delays are 5㎳ (0.5T), 14㎳ (1.5T) and 23㎳ (2.5T), and the amplification delays are 9㎳ (1T) and 18㎳. Since it is (2T), it is a preferable design method to avoid amplification delay time and use attenuation delay time in delay time design.

Currently, there are two types of delayed time delays for MS stage electric primers in Korea. Therefore, a primer having a delay time that can avoid the amplification of the blasting vibration and can be maintained at the vibration level of a single hole can be selected as a primer having a delay time of 25 kHz.

If you use a 20㎳ primer, the amplitude of the vibration is expected to be almost identical to the 18㎳ amplification delay time. Therefore, a delay time of 40㎳ will be obtained by subtracting one of the primer numbers (eg 1, 2, 4, 6). You can decide.

However, since the delayed parallax design cannot sufficiently utilize the attenuation effect due to the blasting vibration interference between the delayed parallaxes, the delayed parallax adjustment by the multistage blasting apparatus is required. If an electron primer is used, all three of the attenuation delays can be used, and as shown in the 0.5T modeling 20 of FIGS. 6A to 6C, the vibration attenuation will be determined as the best delay time of 5 ㎳.

From the determination step 13 of the use primer, it is preferable to select a primer having a 25 kHz delay time delay and a 25 kHz primer capable of initiating more blast holes per blasting.

In addition, when detonating more blast holes at the same time by using a multi-stage blasting machine, if the thermal delay time is selected as 14㎳, the delayed time difference coincides with or close to 9㎳ and 18㎳, which is caused by the ignition error of the primer. Primer numbers with a small range of speech errors should be used.

The range of the utterance error of the primer is related to the inherent delay time of the primer, and the larger the inherent delay time, the larger the range of ignition error. The range of ignition error of primer with 20 ㎳ step, which is most used in Korea, is known as 5% of delay time (eg, ± 2.5 경우 for 5 뇌 with 100 지연 delay).

9 is a delay parallax design diagram of a preferable two-row and eight-column blasting pattern using a primer having a delay time of 20 Hz.

Blasting holes in the first row 40 closest to the free surface 30 are loaded with explosives No. 1 primer having an intrinsic delay of 20 ㎳ with explosive charge, and the blast at each row is 5 ㎳. That is, one of the two lines of the primer of the first row blast hole 41 is connected to the left terminal of the terminal box 52 of the multistage blasting machine 50, and the other line is the second row. One of the two wires of the first row of primers, one of the two wires of the primer of the blast hole 42 of the second row is connected to the left terminal of the terminal box 52 of the multistage blasting machine 50 Another line is connected to one of the two lines of the second row and the second column of primers, and in this way to the terminal box 52 of the multistage blasting machine 50 for the remaining blast holes One of the two lines of the primer of the blast hole 43 of the row is connected to the left terminal of the eighth terminal of the terminal box 52 of the multistage blasting machine 50, and the other one of the two lines of the primer of the second row of eight columns Connect to one of the lines.

Subsequently, the blasting holes in the second row 45 are loaded with the explosive primer 3 with an inherent delay of 60 Hz, and the other line of the primer of the blasting hole 46 in the first row of the second row 45 is multistage. Connect to the right terminal of the first box of the terminal box 52 of the blasting machine 50, and the other line of the primer of the blast hole 47 of the second row is the right terminal of the second box of the terminal box 52 of the multistage blasting machine 50 Connected to the terminal box 52 of the multistage blasting machine 50 for the primer of the remaining blasting holes in this manner, and the other line of the primer of the blasting hole 48 of the last eighth row is connected to the terminal of the multistage blasting machine 50. Connect to the right terminal of the 8th terminal of the terminal box (52).

After this connection, the instrument panel 51 of the multi-stage blasting machine 50 is operated to adjust the second circuit to be blasted at 25 도록 to have a delay difference of 5 보다 from the first circuit, and the third circuit to the second circuit. The blasting time is adjusted to blast at 30 ms to have a delay time of 5 ms, and the blast second time is adjusted to have a delay time of 5 ms than the previous circuit in the circuits 4 to 8 as in the above.

Therefore, the primer loaded in the blast hole of the first row 41 of the first row 40 has a delay time of 20 ms, and the primer loaded in the second column 42 of the first row 40 has a 25 Hz delay. Delay parallax, ..., the primer loaded in the blast hole in the eighth column 43 of the first row 40 is adjusted to have a 55 kHz delay parallax.

Subsequently, the blasting holes in the second row 45 are loaded with the explosive primer 3 having an inherent delay of 60 ms, so that the primers in the blasting hole 46 in the first row of the second row 45 have a 60 ms delay delay. The primer loaded in the second column 47 of the second row 45 has a delay time of 65 ms, and the primer loaded in the blast hole of the eighth column 48 of the second row 45 Adjusted to have a 95ms delay time difference

As described above, the blasting intervals of the blast holes formed by the plurality of rows and the plurality of columns have a time difference corresponding to one half of the vibration period of the target ground of the concerned area so that the vibrations caused by the blasting in the affected area are canceled with each other.

As described above, by analyzing the frequency characteristics of the ground of the area of concern due to blasting and designing the optimal delay time and dose between each stage of one blasting, the blast vibration in the area of concern is less than the level of blasting vibration occurring in a single blasting hole. By maintaining vibration levels, damage to blast pollution can be minimized.

Claims (5)

A test blasting step (10) for measuring a reference waveform giving the most vibration to a region of concern; Frequency analysis of the measured reference waveforms to calculate frequency characteristics of the target ground of the damage area of concern; Obtain the frequency representing the largest oscillation speed in the frequency characteristic of the reference waveform and set the period of the reference waveform by the inverse, and set the integer multiple of 1/2 of the period as the delay time to minimize the blasting vibration for the area of concern. Determining a possible delay time difference (12); Determining a used primer according to a delayed parallax characteristic of a primer to be applied to a blasting site; The method for designing the delayed lag reduction through the frequency analysis of the target ground, characterized in that the design of the optimum delay time difference according to the primer after the determining the use primer. The reference waveform according to claim 1, wherein the reference waveform is selected as a reference waveform having a component having the largest amplitude among the transverse component 15, the vertical component 16, and the tangential component 17 of the acoustic wave transmitted to the damage area. Blasting vibration reduction delay parallax design method through the frequency analysis of the target ground, characterized in that. The method of claim 1, wherein the test blasting step (10) is a waveform by a single hole blasting or as a waveform for the first blasting hole or the last blasting hole having a delay difference of about 1,000 ms (1 second) from the main blasting. Design method for reducing lag vibration by frequency analysis of the target ground, characterized in that the. The method according to claim 1, wherein the optimal delay time design step (14) forms a blast hole in a plurality of rows and a plurality of columns, and sets the interval of the blast second time between the blast holes from the first column to the last column of the first row. Is 1/2 of, and the blast second of the first column of the second row is delayed 1/2 of the reference waveform period from the blast second of the last column of the first row, and is set to the last column of the last row at the blast second time interval. Design method for reducing lag vibration by frequency analysis of the target ground, characterized in that the. The blast second time between the blast holes from the first column to the last column of the first row is an integer multiple of 1/2 of the reference waveform period, and the blast second time of the first column of the second row is 1. Delay time blast vibration reduction through frequency analysis of the target ground, characterized by delaying an integer multiple of 1/2 of the reference waveform period from the blast second of the last column of the first row, and setting up to the last column of the last row at the blast second interval. Design method.

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