JP2881179B2 - A method for determining the safest maximum charge in perforation blasting. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a) Industrial application field The present invention is effective for performing test blasting and actually breaking rock at the site where the hardness of rock is unknown at the site where the hardness is unknown. The present invention relates to a method for quickly and reliably determining a safe and safe maximum charge amount.

b) Description of the Related Art Conventionally, Hauser official as a calculation expression that determines the charge amount of blasting, i.e., it is well known Sokusuriryou L (kg) = blast constant C × minimal resistance wire W ^3. This formula is a formula for the volume of a cone, V
= 1/3 x π x r ² x h. If both r ² and h are replaced by W, the Hauser formula is realized.

c) Problems to be Solved by the Invention This Hauser's formula is accurate as long as the volume of the explosive is assumed to be 0 and the charging position is considered as a minimum point.

However, in actual blasting work, the charge has a predetermined length and diameter, and in particular, in recent years, with the enlargement of machines, the blasting perforation length may reach, for example, 22 m, and the long perforation length In contrast, charging is performed in a long rod-like state. Thus, Hauser's formula is not suitable for the practice of rod-shaped charging.

The most important thing to note about drilling blasting is the risk of stepping stones caused by blasting.If the amount of charge is excessive, the surrounding area, including workers, is at risk of stepping stones. It is. However, if only the danger of stepping stones is considered excessively and the amount of charge is too small, the working efficiency will not be improved, and even if it is safe, the completion of the construction will be delayed.
Therefore, in order to balance both work safety and efficiency,
Even if a stepping stone is generated by the blasting, a method is required to quickly find a safe maximum charge amount at the work site, which is a limit point where actual damage by the stepping stone does not occur.

An object of the present invention is to perform a test blast to achieve both work safety and efficiency when actually starting a drilling and blasting operation at a site where the hardness of the rock is unknown, and to use a stepping stone generated by the blasting. It is an object of the present invention to provide a method for quickly, surely, easily and easily determining the maximum amount of charge, which is a critical point at which no actual harm occurs.

d) Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a method for forming a hole having a desired specific gravity A in a hole formed by a desired hole length H and a hole diameter r. When the test blasting is performed, first, the charging amount at a scale where the effect of the blast appears on the ground surface is set to the minimum charging amount L, and the charging length at that time is set to the minimum charging length l, and L = (π / 4 ) R ² · l · A Confirm D = H−1 as the initial length D of the loaded object at that time, and then determine the length of 3/4 of the initial length D as the auxiliary charge length. l
a, that is, la = (3/4) D, and the total charge amount L + La obtained by adding the auxiliary charge amount La corresponding to the auxiliary charge length la to the minimum charge amount L, that is, L + La = (π / 4) r ² (l + la) A is defined as the safest maximum charge amount, and piercing blasting is performed at the safest maximum charge amount L + La.

Further, in order to achieve the above object, the present invention sets the length of the initial filling length D to 1/2 of the auxiliary charge length l ', that is, l' = (1/2) D, The total charge amount L + La 'obtained by adding the auxiliary charge amount La' corresponding to the charge length l 'to the minimum charge amount L, that is, L + La' = (π / 4) r ² (l + l ') A is standardized. The point is that the drilling blast is performed with the standard charge L + La 'as the charge.

e) Action A test blast is performed to first confirm the initial inclusion length D at the minimum charge L at which the effects of the blast appear on the ground.

However, only the minimum charge amount L causes cracks on the ground surface, and the rock near the ground surface is too weakly destructed, so that post-processing takes time and labor, and the work efficiency is not improved. Therefore, it is judged that there is still room for destruction of the rock near the ground surface.

Therefore, the initial charge length D at the minimum charge amount L is 3 /
If the auxiliary charge amount La corresponding to the length of 4 is added to the minimum charge amount L so that blasting occurs near the undeveloped ground surface, the actual damage due to the stepping stone does not occur. Destruction without excess or shortage is obtained, and both safety and efficiency are satisfied.

On the other hand, if the auxiliary charging amount La ′ corresponding to half of the initial filling length D is added to the minimum charging amount L, the standard charging amount L + La ′ which is safest to break the rock is obtained. can get.

f) Example In FIG. 1, the perforation diameter r (mm), the perforation length H (m) = the charging length l (m) + the initial inclusion length D (m) The fractured rock mass V (m ³ ) is a cone From the formula for calculating the volume of, the amount of fractured rock mass V (m ³ ) = 1/3 × π × fracture radius R ² (m ² ) × perforation length H (m) = perforation length H (m) × fracture radius R ² ( m ² ) The minimum charge amount L (kg) is obtained from the formula for calculating the volume of a cylinder, the minimum charge amount L = the cross-sectional area of the cylinder (π / 4) r ² × the charge length 1 × the specific gravity A of the charge In the test drilling blast configuration having various specifications, the point x (m) in the drilling length H (m) indicates the boundary between the minimum charge length l (m) and the initial load length D (m). x
When a point is charged and blasted, the blasting force is such that the ground surface GL slightly rises, and the explosive required for the blasting becomes the minimum charged amount L (kg). Therefore, the initial inclusion length D at that time
Check (m). For example, in the case of a hole of H = 14 m and r = 140 mm, when the test blasting is performed by charging with the minimum charging length l = 7 m, if the ground surface GL is affected, the initial load length D = 7m.

However, the minimum charge L (kg) under the above conditions
In the case of bombing, when examining the situation of rock destruction,
As shown in FIG. 1, a slight crack is generated in the vicinity of the ground surface GL, and such a degree of destruction requires time and labor for post-processing work, which is inefficient.

Therefore, to realize efficient work in post-processing,
If a charge is added to some of the portion of the initial inclusion length D (m) and blasted, crushing near the ground surface GL, that is, fragmentation of the bedrock can be obtained. However, if the charge is excessively added, actual harm due to the stepping stones occurs, which becomes dangerous and makes it difficult to perform the work itself.

The inventor of the present invention has conducted many experiments, and as a result, as shown in FIG. 2, the auxiliary charge amount La (kg) is 1 / the initial load length D (m).
The length of 2 is the standard value Xa (m), and the length of 3/4 is the safety limit
With Xb (m), it was confirmed that there was no danger of actual harm due to stepping stones. That is, the initial inclusion length D in the above embodiment.
In the case of = 7m, the standard value Xa is 1/2 of the standard value, and therefore the final inclusion length Da is 3.5m, and the danger value Xb is 3/4 of D = 7m, that is,
If it is less than 5.25 m, work can be performed. The total charge amount L + La obtained in this way is 10.5 m in the case of the perforation length H = 14 m, and the standard charge value is 12.25 m.
Is the safety limit.

The smaller the perforation diameter r, the more the standard value Xa and the safety limit value
Xb increases and decreases as it gets thicker.

g) Effects of the present invention As described in detail above, the present invention
First, the initial load length D at the minimum charge L at which the effects of the blast appear on the ground surface during the test blasting is confirmed, and based on the value, 3/4 of the length of the initial load length D is determined. Is added to the minimum charge L as the auxiliary charge La,
Perforation blasting was performed with the maximum safety charge L + La (kg) thus obtained. Accordingly, since the blasting can be performed using the maximum amount of charge within the safety limit that does not cause actual damage due to the stepping stone, both safety and efficiency of the work have been achieved. Furthermore, if the auxiliary charge amount corresponding to a length of 1/2 of the initial inclusion length D is added to the minimum charge amount and the blasting is performed with the standard charge amount obtained in this manner, stepping stones are obtained. Safe blasting that does not occur is guaranteed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a first step of the method of the present invention, and illustrates a state of a rock mass which is destroyed by a minimum amount of charge L that appears on the surface of the ground due to blasting caused by test blasting. FIG. 2 is an explanatory view showing a second step of the method of the present invention, wherein a safe maximum charging amount L obtained by adding the auxiliary charging amount La to the minimum charging amount L.
A state in which perforation blasting is performed with + La and a state in which perforation blasting is performed with a standard charge L + La ′ obtained by adding the auxiliary charge La ′ to the minimum charge L are illustrated. H (m): Perforation length, l (m): Minimum charge length, la, l '(m) ... Auxiliary charge length, l + la (m) ... Safety maximum charge length, l + l' (m ) Standard charge length D (m) Initial load length, Da (m) Final load length, L (kg) Minimum charge amount, La, La '(kg) Auxiliary Charge amount, L + La (kg): Maximum safe charge amount, GL: Ground surface.

Claims (2)

(57) [Claims] When a test blast is carried out by putting a desired charge amount having a charge specific gravity A into a hole formed by a desired perforation length H and a perforation diameter r, first, the effect of the blasting is reduced to the surface of the ground. Let L = (π / 4) r ² · l · A be the initial charge length, where L is the minimum charge amount L and the charge length at that time is the minimum charge length l. Confirm D = H-I as D. Next, the length of 3/4 of the initial inclusion length D is set to the auxiliary charge length la,
That is, la = (3/4) D, and the total charge amount L + La obtained by adding the auxiliary charge amount La corresponding to the auxiliary charge length la to the minimum charge amount L, that is, L + La = (π / 4) ) R ² (l + la) A is the maximum safe charge, and the maximum safe charge L + La is used for blasting. The method for determining the maximum safe charge in puncture blasting. 2. When a test blast is carried out by putting a desired amount of charge having a specific gravity A of charge into a hole formed by a desired perforation length H and a perforation diameter r, first, the effect of the blasting is reduced to the surface of the ground. Let L = (π / 4) r ² · l · A be the initial charge length, where L is the minimum charge amount L and the charge length at that time is the minimum charge length l. Then, D = H−l is confirmed as D. Next, the length of half of the initial filling length D is set to the auxiliary charging length l ′, that is, l ′ = (1/2) D, The total charge amount L + La 'obtained by adding the auxiliary charge amount La' corresponding to the charge length l 'to the minimum charge amount L, that is, L + La' = (π / 4) r ² (l + l ') A is standardized. A method for determining a standard charge amount in piercing blasting, wherein the blasting is performed with the standard charge amount L + La 'as the charge amount.