JPH06323796A - Blasting method - Google Patents

Abstract

PURPOSE:To reduce blasting vibrations and noises in bench blasting by using both electronically delayed electric detonator caps and electric detonator caps having delay composition as a delaying means in such a manner that the electronically delayed electric detonator caps are installed in specified locations and the electric detonator caps having delay composition as a delaying means are installed in locations other than the specified locations. CONSTITUTION:The title bench blasting is carried out by using electronically delayed electric detonator caps for 6 vertical holes #1-#6 in which a large amount of powder is charged and delay composition type MS electric detonator caps for a large number of, i.e., 30 horizontal holes #8-#17 in which a comparatively small amount of the powder is charged. Because beddrock is straightly, smoothly finished between the holes without being damaged, overbreak, unfixed stone removing work and hindering stone removing work in assembling supporting are reduced. Bedrock protection and safety are enhanced. An accurate concrete laying plan can be established.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blasting method suitable for use in, for example, a smooth blasting method in tunnel excavation or the like and a bench blasting method such as quarrying.

[0002]

2. Description of the Related Art In a smooth blasting method for tunnel excavation or a bench blasting method such as quarrying, a DS electric detonator or an MS electric detonator, which is a method of delaying the detonation time by burning a delay agent, has been conventionally used when performing step blasting. A detonator is used.

In the smooth blasting method in tunnel excavation and the like, as elements required for finishing rock mass smoothly by blasting, the intervals of blasting holes, drilling accuracy, resistance wire length, dose amount and detonator accuracy per second. Examples thereof include a cushion blasting method using an explosive having a diameter smaller than the blast hole diameter, a line drilling method using a large number of holes, and the like.

By the way, these construction methods have problems that the number of drilled holes is very large, it is troublesome, and if the rock quality changes, a sufficient effect cannot be obtained.

Further, the bench blasting method of quarrying with light has a problem of vibration and noise of blasting. As a countermeasure against it, blasting vibration and noise are separated into stages like a DS electric detonator. There have been attempts to reduce the size of the vibration waves and noise waves by interfering with vibration waves and noise waves, like the MS electric detonator.

[0006]

However, it is known that the electric detonator using the conventional prolongation agent has a variation in time per second of 1 to 5%. For example, the best method of the tunnel smooth blasting method is As the DS electric detonator used for the final detonation of the outer hole, a detonator with a long time of 2 to 3 seconds is usually used, and the variation in this time is 20 to 1
It will have a variation of about 50 ms. As described above, no matter how much the cushion plasting method, the line drilling method, or the like is devised, it is difficult to finish the excavated surface smoothly if the electric detonator to be used has poor accuracy in seconds.

Further, in the bench blasting method, as described above, the MS electric detonator is used for the purpose of the interference effect of the blasting vibration wave, and the DS electric detonator is used for the purpose of the separation effect. Therefore, the present situation is that satisfactory results have not been obtained in reducing blast vibration and noise.

As described above, in any of the conventional methods, since the combustion speed of the prolongation agent is used as the initiation time, there is a large variation in the initiation time interval, and a fundamental solution to the reduction of blast vibration and noise has not been reached. The current situation is that many sites are forced to reduce the scale of blasting and switch from blasting to machine digging.

An object of the present invention is to provide a blasting method capable of solving the above-mentioned conventional problems, satisfactorily smoothing the excavated surface in tunnel excavation, and reducing blasting vibration and noise in bench blasting. To do.

[0010]

In order to achieve the above object, the blasting method of the present invention, in the blasting work, is composed of an electric energy storage capacitor, a delay circuit, a switching circuit and a flashing electric detonator to achieve a high accuracy in seconds. The electronic delay electric detonator has is installed at a predetermined location, an electric detonator using a delay agent as a delay means is installed at a location other than the predetermined location, and both are used together in one blasting operation.

Here, the time accuracy of the electronic delay electric detonator may vary depending on the purpose, but is usually 10 ms, more preferably 5 ms or less, and most preferably within 1 ms. .

[0012]

According to the blasting method of the present invention, the use of an electronic delay electric detonator having a high time accuracy only in a necessary portion allows, for example, the destruction of explosives around the outermost charge hole of a tunnel. The force can be controlled in seconds of the detonator, and by exerting a destructive effect only in a specific direction, it acts as a break rather than a crush of the bedrock.

By this, without damaging the bedrock,
Since the holes can be finished linearly and smoothly, it is possible to reduce overburden, fluff (damaged area) dropping work, and picking work during support assembly, improving the rock mass protection and security. It is possible to accurately plan the concrete for casting.

In the case of bench blasting, the blasting vibration and noise generated in the holes in the front stage can be interfered with the waves in the rear stage to reduce the blasting vibration and noise. Also, at the site where mechanization was forced,
It can greatly contribute to the improvement of environmental problems, the efficiency of blasting, and the improvement of cost problems.

[0015]

EXAMPLES The blasting method of the present invention will be described in detail below with reference to examples.

<Example 1> As shown in FIG. 1, in a small-section tunnel T with a hard rock of fine-grained granite and an elastic wave velocity of around 6000 m / s, which entered approximately 1500 m from the 550 m elevation of Mine A. Blasted smooth blasting.

The blasting pattern is as shown in FIG. 2, and 11 steps of blasting were carried out for a tunnel section having a substantially horseshoe section. The outermost peripheral blast hole H (H ₁ ~) of the 10th of the 11 stages (the numbers in the circles represent the stages)
H ₁₄ ) used a smooth blasting explosive with a hole interval of about 45 cm. The hole spacing is preferably in the range of 30 to 100 cm as in the conventional case.
Furthermore, for the _{1st to} 9th and 11th steps, a DS electric detonator was used, and the blast hole (H _{1 to} H
₇ ) DS electric detonator, right-side blast hole (H ₈ ~ H ₁₄ ) electronic delay electric detonator with high time accuracy (2300 ms ± 1 m)
s) was used, and the delay time was set to a predetermined second within an accuracy of 1 ms per second. Regarding the electronic delay electric detonator used here, Japanese Patent Application No.
No. 58471.

In order to investigate the damaged area of the ground by the smooth blasting method using these two types of detonators, Line-A (electronic delay electric detonator side) and Line as shown in FIGS. 1 and 3 are used. -B (DS electric detonator side) 2
Sensors S _{1 to} S _n were installed on the survey line, elastic wave survey was performed, and the damaged region was measured.

Line obtained by the above elastic wave exploration
Fig. 4 (a) shows the travel time curve of -A (electronic delay electric detonator side)
Fig. 4 shows the travel time curve of Line-B (DS electric detonator side).
It shows in (b). In both figures, the impact point (Sh
Looking at the running time at a distance of 2 m from the ot point),
Line-A is about 0.4 ms, Line-B is about 0.8 ms, and Line-B side is Line-A.
The arrival time is much slower than on the side, and it is considered that the rock mass is being damaged by this amount.

Further, assuming that the damaged region around the tunnel T has a layered structure and the elastic wave velocity is higher as the layer becomes lower, the results of the surface layer removal method are shown in FIGS. 5 (a) and 5 (b). Shown in.

From the travel time curve, the Line-A side is 2
The layer structure and the Line-B side were calculated as a three-layer structure. According to this, the surface layer (first layer) on the Line-A side has a maximum thickness of about 100 mm and an elastic wave velocity V ₁ of 178.
0 m / s, while the surface layer on the Line-B side (first
Layer) has a maximum thickness of about 250 mm and an elastic wave velocity V ₁ of 1
040 m / s, and Line-B side is Line-
It can be seen that the damaged layer is thicker than the A side.

Further, on the Line-B side, the bedrock of the second layer (intermediate layer) having an elastic wave velocity V ₂ of 4560 m / s is 1
It can be seen that it exists with a thickness of around m and is considerably damaged as compared with the Line-A side. in this way,
On the Line-B side where a DS electric detonator is used for all stages, the rock pain of about 1 m at the maximum occurs, whereas L that uses both a DS electric detonator and a high-speed electronic delay electric detonator is used.
As described above, the pain on the ine-A side was about 100 mm at maximum, and it was confirmed that there was a particular difference in the effect.

<Embodiment 2> In the bench blasting of the specifications shown in FIG. 6 and Table 1, an electronic delay electric detonator was installed in 6 vertical holes with a large amount of drug, and a large number of holes with a relatively small amount of drug were placed next to each other. Hole 3
Blasting was performed by using an MS detonator of the procrastination method in the 0 hole.

First, prior to this experiment, in order to determine the detonation time interval of the explosive, the column charge was used to measure
O) One hole of 75 kg of explosive, 100 g of 3 paulownia dynamite as a parent die, equipped with an instantaneous electric detonator, 500 m from the face
The vibration waveform and low-frequency sound waveform at the point were measured.

As a result of synthesizing based on this waveform using a linear superposition principle by a computer and performing an analysis, the initiation time interval at which the vibration is minimized was 20 ms.

Based on the result of the second time design, the blasting pattern shown in FIG. 6, that is, the initiation delay time of the first vertical hole is set to 10 ms, and the sixth hole is sequentially delayed by 20 ms, and the horizontal hole is set to 30. As for the holes, as shown in Fig. 6, when blasting was carried out at the steps of # 8 to # 17, compared with the current blasting (using only MS electric detonator) shown as a comparative example in Fig. 7 and Table 1 of the same scale, It was confirmed that the blast vibration at 500 m was reduced by 40% and the low frequency sound was reduced by 4 dB.

[0027]

[Table 1]

[0028]

In the smooth blasting method for tunnel excavation or the like by the blasting method of the present invention, the pain of rock is suppressed to about 1/10 to 1/5 of that of the conventional blasting method, and almost linearly. Since it can be finished to a smooth surface, it is possible to reduce overburdens, floating stones (damaged areas) work, support work during support work assembly, etc., and it is possible to improve the protection and safety of rock mass and You can make an accurate plan for construction concrete.

Further, in the method of blasting a quarrying bench with a light, a blasting vibration and a noise (low frequency sound) are usually about 40, respectively, as compared with blasting using an electric detonator of prolongation system.
%, 4 dB could be reduced, but since these results are below the regulation values of each blasting vibration and noise, the blasting scale can be expanded to about 1.5 times.

[Brief description of drawings]

FIG. 1 is a sectional view showing a positional relationship at an experimental site.

FIG. 2 is a sectional view showing the arrangement of blast holes when the present invention is applied to a tunnel smooth blasting method.

FIG. 3 is a cross-sectional view showing a positional relationship between a survey line and a sensor when elastic wave exploration is performed using a sensor in a damaged region of the ground after blasting.

FIG. 4 is a graph showing a travel time curve obtained by elastic wave exploration.

FIG. 5 is a graph showing the results obtained by the surface removal method from the results of FIG.

FIG. 6 is a diagram showing a blasting pattern in which an electronic delay electric detonator for blasting a quarry bench and a delay time type electric detonator are used together.

FIG. 7 is a view showing a delayed chemical electric detonator blasting pattern for blasting a quarry bench.

Claims (1)

[Claims] 1. In a blasting operation, an electronic delay electric detonator having a high second-time accuracy, which is composed of an electric energy storage capacitor, a delay circuit, a switching circuit and a flash electric detonator, is installed at a predetermined position, and other than the predetermined position. A blasting method characterized by installing an electric detonator with a delay agent as a delaying means, and using both together in one blasting operation.