JPH01285800A - Shot-firing - Google Patents

Abstract

PURPOSE:To enable suppression of vibration and reduction of a thickness unit by a method wherein explosive layers dispersed and charged in a plurality of holes and each shot-firing hole are initiated by means of an electric detonator having an electric delay circuit. CONSTITUTION:An explosive in an amount being 2/3-3/4 of a general whole charge amount and a detonator are charged, and detonators are selected and accurately charged in respective explosive layers so that shot-firing holes 1 formed in 2-3 explosive layers are initiated at intervals of several hundred ms, in order, from a layer the nearest to the port of the shot-firing hole. A vibration waveform generated from each explosive layer is measured. The vibration waveforms are synthesized at intervals of a second time between various explosive layers. Vibration waveforms only for the number of shot-firing holes considered to be generated when initiation is made at a regular blasting at an optimum second distance of a minimum vibration value are synthesized at intervals of an optimum second time between the shot-firing holes. The use of an electric detonator and a dispersion charge enables reliable suppression of vibration and saving of a charge amount.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a blasting method.

[Prior art] Conventionally, when blasting is carried out near structures or urban areas, vibrations caused by blasting pose a problem, so the amount of charge per hole has been reduced and multistage blasting has been carried out using staged electric detonators. I've been there.

Furthermore, in bench blasting and the like, attempts have been made to reduce vibration by using DS71i detonators instead of MS, and by taking advantage of variations in surrounding arrangement.

Historically, today there is a method of suppressing blasting vibration using a high-second precision detonator using an IC circuit (Japanese Patent Laid-Open No. 82-26190
No. 0) is introduced.

[Problem to be solved by the invention] However, with conventional staged electric detonators (those that use a time-delaying charge), attempts to reduce vibration by taking advantage of peripheral installation variations are not always successful, and sometimes cause vibrations to become large. This could be very difficult to control.

Further, in the method of suppressing blasting vibration using a high-second precision detonator using an IC circuit, although it is effective in suppressing vibration, there is a problem in reducing the basic unit.

[Means for solving the problem] In order to solve the above problems, the present inventors have developed a more effective f
・I found the steps.

That is, in the work of blasting multiple holes at once, the present invention disperses explosive charges in six holes (deck-charges), and uses an electric detonator having an electric delay circuit to charge each explosive layer and each blasting hole with the dispersed charge. This is a blasting method characterized by detonation.

First, in order to determine the detonation time interval of an electric detonator having an electric delay circuit prior to the main blasting, one blast hole is drilled and the same dispersed charge as used in the main blasting is applied. As for the dispersion charging method, first, place one hole in the bottom of the melon, which is 2/3 to 2/3 of the total charge.
Load 3/4 detonator and detonator. Next, the charge hole is backfilled with sand, blue powder, etc., and after the remaining explosives and detonator are loaded, the charge hole is backfilled with sand, blue powder, etc. By repeating such operations, two to three explosive layers (decks) are provided. One blast hole loaded in the above manner is selected and detonated in order from the explosive layer closest to the mouth of the blast hole at intervals of several hundred Is, and each explosive layer is loaded correctly. Measure the vibration waveform generated from the It is preferable to start detonating from the explosive layer near the hole mouth, because if the explosion starts from the explosive layer near the hole's end, the surrounding rock will be crushed by the explosion, and the vibrations generated from the upper explosive layer will not be sufficiently transmitted.

Next, the vibration waveforms generated from each explosive layer are combined according to the linear superposition principle at various seconds-time intervals between the various explosive layers (deck-to-deck) to predict the vibration waveform likely to be generated from a single blast hole. Note that this method is, for example, “A Metho
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Among these, the second time interval between each explosive layer when the vibration value (maximum displacement speed, vibration level, etc.) is the smallest is defined as the optimum second time interval between each explosive layer in the main blasting. Next, the vibration waveforms that are expected to be generated from one blast hole when each explosive layer obtained by the above calculation is detonated at the optimal second time interval are synthesized for the number of blast holes at the second time interval between various blast holes, The vibration waveform that is expected to occur during the main blasting is predicted n1. Among these, the second time interval between each blast hole when the vibration value (maximum displacement speed, vibration level, etc.) is the smallest is defined as the optimal second time interval between each blast hole in this blasting. Furthermore, as another method for setting the seconds time interval, first, the seconds time interval between each explosive layer is determined appropriately, and the vibration waveforms generated between each explosive layer are synthesized at the determined seconds time interval, and then the vibration waveforms generated from each explosive layer are synthesized at the determined seconds time interval. Predict the vibration waveform that is likely to occur. Next, this vibration waveform is synthesized for the number of blast holes at seconds time intervals between various blast holes, and the vibration waveform that is expected to occur during the actual blasting is predicted. The second time interval between each blast hole when the vibration value is the smallest in this width is defined as the optimum second time interval between each blast hole in this blasting. In this method, it may not be possible to reduce the vibration value depending on how the second time interval between each explosive layer is determined. In that case, a similar calculation is performed to determine the optimal second time interval by changing the second time interval between each explosive layer.

An electric detonator having an electric delay circuit is created according to the optimum second time interval between each explosive layer and blast hole obtained through the above analysis. Incidentally, when the second time interval is t aS and the standard deviation l of the variation in the detonation time of each detonator is σ-6, it is necessary to use a detonator having a second accuracy that satisfies the following formula.

t/σ≧10 When t/σ<10, the vibration value may not be reduced due to variations in the detonator itself.

Incidentally, electric detonators having such timing accuracy are disclosed in Japanese Patent Application Laid-open Nos. 57-142498, 62-35040, and 62-91799.

The problems of the prior art can be solved by carrying out main blasting using an electric detonator having such an electric delay circuit and a dispersed charge as described above.

[Example] In lime with a bench height of 15-, the pore diameter was 165Iφ,
Bench blasting was performed with a hole length of 18-1, a hole spacing of 7-1, and a resistance line of 6.5.

First, in order to determine the detonation time of the electrically delayed detonator with high time accuracy prior to the main blasting, the Anpho explosive 13
7.5kg/hole (lower 100.0kg.

Upper deck 37.5kg), 100g of 3 paulownia dynamite as a parent die was equipped with an electric delay detonator with high precision of timing as shown in Japanese Patent Application Laid-open No. 62-91799, and the upper deck was removed 48 seconds after energization, and after 600ss. Explode the lower deck,
Vibration velocity waveforms at 1001 points from the face were measured. Based on this waveform, we synthesized and analyzed it using a computer using the linear superposition principle, and found that the second time interval at which the vibration is minimum is 15 m5 between the decks. There were 20 holes.

Next, based on this second design result,
799, a highly precise electric delay detonator (15
Using 100g of 3 paulownia dynamite equipped with ss 1-9 stages, 20m51-9 stages) as a group, disperse charge in the same way as above into 9 bench holes, and 100m -15 from the face.
Blasting vibration at the 0 m point was measured. Table this result.
Shown in 1. Table 2 shows the basic unit and second accuracy at this time. Note that the crushing conditions at this time were good.

Comparative Example 1 MS electric detonator (15ss 1-9 stages, 2
The same charge as in the example was used except that 0 m51 to 9 stages) were installed, and blasting vibrations were measured at points 100 to 150 feet from the face. The results are shown in Table-1.

Table 2 shows the original 111th place and second accuracy at this time.

Incidentally, the crushing conditions at this time were worse than in the example and required corrective blasting.

Comparative Example 2 On the same bench as in Example, first, prior to main blasting, in order to determine the detonation time of the electrically delayed detonator, 175.0 kg of Anho explosive was charged per hole using a columnar charge, and instantaneous electricity was applied to 100 g of 3 paulownia dynamite as a group. Attach a detonator and perform blasting with a single hole,
The vibration velocity waveform at a point 100 m from the face was measured. As a result of computer analysis based on this waveform, the second time interval at which the vibration was minimum was 1518 seconds between holes.

Next, based on this second design result,
799, a highly precise electric delay detonator (15
3 paulownia dynamite 100g equipped with ss 1 to 9 stages)
A columnar charge similar to that described above was placed in nine bench holes, and the blasting vibration was measured at points 1001 to 150 from the face. The results are shown in Table-1. Table 2 shows the original 11th place and second accuracy at this time.

Note that the crushing conditions at this time were as good as in the examples.

Comparative Example 3 The same charge as in Comparative Example 2 was carried out except that a MS electric detonator (15ss 1 to 9 stages) was installed using a delay charge, and the blasting vibration was measured at points 10 (1 m to 1501) from the face. The results are shown in Table 1.The unit consumption and accuracy in seconds are shown in Table 2.The crushing conditions at this time were as good as in the examples.

Table-1 However, P is the maximum vibration velocity in the vertical direction (unit: C/5ec
), L indicates the vibration level (unit: dB).

Table 2 As described above, by using the present invention, the vibration value can be reduced. Moreover, the reduction ratio of the total unit consumption when dispersing the charge using a conventional electric detonator (1-Comparative Example 1/Comparative Example 3-0.
04) Reduction rate of total unit consumption when dispersing charge using an electric detonator with higher time precision than 04) (11 Examples/Comparative Example 2)
-0.12) is much larger.

[Effects of the Invention] According to the blasting method of the present invention, an effect even more superior to the effect of reducing blasting vibrations using a dispersed charge can be obtained. Even more surprisingly, it was possible to obtain the same crushing amount as conventional blasting with a charge amount that was approximately 5% lower than that calculated using conventional blasting designs.

Patent applicant: Asahi Kasei Industries, Ltd. Agent Patent Attorney Hidetake Komatsu

Claims (1)

[Claims] In the process of blasting multiple holes at once, the explosives in each hole are dispersed (deck charged), and each dispersed layer of explosive and each blast hole is detonated using an electric detonator having an electric delay circuit. A blasting method characterized by