JPH03221800A - Determination of safety most loading dosage in hole drilling blasting - Google Patents

Abstract

PURPOSE:To ensure highly effective blasting work by determining most loaded dosage at a limit point where no actual harm is existent by drilling a hole of its length and diameter within a range from a standard value yielded from a hole bottom and a maximum value. CONSTITUTION:There is drilled a hole of its length and diameter at a ratio of a loading dosage corresponding to 1/2 of the length from a hole bottom to the amount of a destroyed base rock, i.e., in a range of 0.08-0.11 in a destroyed base rock unit, and hole drilling blasting is performed at a final loading dosage within a range where 2/3 of the length from the hole bottom is taken as a standard value and 7/10 is taken as the maximum value.

Description

DETAILED DESCRIPTION OF THE INVENTION a) Industrial Applications This invention relates to a method for quickly and reliably determining the safe maximum charge amount effective for destroying rock.

b) Conventional technology Conventionally, Hauser's formula was used as a calculation formula to determine the amount of charge for blasting: Charge amount L (kg) = Blasting constant CX Minimum resistance &IW"
is well known. This formula is the formula for calculating the volume of a cone v
= '8X1Xr'' A variation of
If we replace both with W, Hauser's formula will be realized.

C) Problems to be Solved by the Invention This Hauser's formula is accurate as long as the volume of the gunpowder is assumed to be 0 and the position of the charge is also considered as one minimal point.

However, in actual blasting work, the charge has a predetermined length and diameter, and in recent years, as machines have become larger, the length of the blasting hole may reach, for example, 22 m. The charge, on the other hand, is carried out in the form of a long rod.

In this way, Hauser's formula is not suitable for the rod-shaped charging method that is actually used.

The most important thing to be careful about in drilling and blasting work is the risk of flying stones that occur with the blasting.If the amount of charge is excessive, the surrounding zone including work H may be exposed to the risk of flying stones. exposed to However, if too much consideration is given to the danger of flying stones and the amount of charge is too low, work efficiency will not be improved, and the completion of construction work will be delayed even if it is not safe.

Therefore, in order to achieve both work safety and efficiency,
Since flying stones are generated as a result of the explosion, a method is required to quickly find out the safest maximum amount of charge at the work site, which is the limit at which no actual damage is caused by the flying stones.

The purpose of this invention is to reach the maximum number of bags of 3, which is the limit point at which actual damage from flying stones caused by explosions will not occur! It is an object of the present invention to provide a method for quickly, reliably, and simply determining the amount of blasting to carry out highly efficient blasting work.

d) Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a method for crushing rock with a charge amount equivalent to 1/2 of the length from the bottom of the hole! 1! In other words, drill a hole with a hole length and diameter within the range of 0.08 to 0.11 for the fractured rock unit, and use 2/3 of the length from the bottom of the hole as the standard value. , 7/10 as the maximum value.

The condition is that the ratio of the final charge amount to the amount of broken rock, that is, the unit of broken rock, is within the range of 0.25 to 0.35.

e) Effect As shown in Figure 2, for example, if you conduct a test blast and check the initial charge length at the minimum charge ff1L at which the impact of the blast will be felt on the ground surface, you will find that the length of the hole is approximately 1
/2.

However, with this minimum charge of NIL alone, cracks are created on the ground surface, and the destruction of the rock near the ground surface is too weak, and post-processing takes time and effort, which does not improve work efficiency. It is judged that there is still room for destruction.

Therefore, as shown in Figure 3, the length is set at 1/3 of the initial charge length at the minimum charge amount. ! The value Xa is 21
Adding the auxiliary charge amount La with the length of 5 as the maximum value xb,
The explosion is made to occur even near the ground surface where the destruction has not yet been completed.

The standard value Xa is 1/2 + 1/6 = 4/ from the bottom of the hole.
6=2/3 length, and the maximum value xb is I/
The length is 2+2/1o=7/10, and their final charges are in the range of 0.25 to 0.35 fractured rock units.

However, if the final charge amount is within the above range and the contrast between the length of the hole and the hole diameter r is extreme, the initial objective will not be achieved. In other words, when the ratio of the charge amount corresponding to 1/2 of the length from the hole bottom to the amount of fractured rock, that is, the fractured rock unit (also known as risk factor or blasting coefficient) is 0.08 to 0.11. Only in the case of a hole with a drilling length and diameter within the range, just the right amount of destruction can be achieved, and actual damage from flying stones will not occur.
Both safety and efficiency are satisfied.

A hole having a drilling length H and a diameter r that meets the above conditions is as follows.

Drilling length (Ham) Hole diameter (r) Question 3 25 4 35 5 40 6 50 7 60 8 70 9 70~80 10 80~90 Drilling length (lI) m 11 2 3 4 5 Hole diameter (r・) 90~1 100~ 1 100~1 110~1 120~1 mm 0 0 0 0 0 f) Example In FIG. I
[! The amount of rock mass V (m3) is determined from the formula for calculating the volume of a cone: Volume of fractured rock mass V (ml) ''/s The radius of fracture F (2tm"1) The minimum charge L (kg) is calculated from the formula for calculating the volume of a cylinder: Minimum charge L (kg) = xx radius of hole diameter 2 x charge length 9
(m)
The point χ(m) in the hole length H(m) is the minimum charge amount fA
If the boundary between l (m) and the initial confined object length D (m) is shown, and the charge is charged up to the χ point and the explosion is performed, the explosive force will be such that the ground surface G and L will rise slightly, and the gunpowder required for that is the minimum charge amount 1. fkg), so when we check the initial filling length D (m) at that time, we find that, for example, H=14m,
If test blasting is carried out with a minimum charge amount R = 7 m in a hole of r = ]40nun, and if there is an effect on the ground surface GL, then the initial charge length D = 7 m, As described in the previous section, rliI D = 7 m is approximately 1/2 of the drilling length H.

However, the minimum charge amount L(
Examining the state of rock destruction in the case of blasting with It is too weak, and with this level of destruction, post-processing work is time-consuming and inefficient. Therefore, it is judged that there is still room for destruction of the rock near the ground surface6.

Therefore, in order to achieve efficient post-processing work, if 6 charges are added to a certain percentage of the initial charge length D (m) and blasted, the crushing near the ground surface G and L can be achieved. Subdivision of the bedrock is obtained.

However, if an excessive amount of charge is added, actual damage from flying stones will occur, making it dangerous and difficult to carry out work No. 6.

Therefore, the present inventor calculated the maximum charge amount L+La, which is the minimum charge amount plus the auxiliary charge amount La, and the auxiliary charge amount L a 1. :If the ratio of the maximum amount of destroyed rock (V+Va), including the amount of destroyed rock (Va) in Based on this, an experiment was attempted to increase the auxiliary charge amount La. As a result, the standard value is 273 from the bottom of the drilling length H, and 7
Total charge amount L + L within the range whose maximum value is the length of /10
If it is a, it is within the above conditions and is confirmed to be safe.

Next, when the above relationship is examined using calculated values, the results are as shown below.

As an example, in the case of drilling length I 130m1m, drilling length H = 15m initial charge length D = 7.5m minimum charge amount 12 = 7.5m (length from the bottom of the hole to point X) fracture radius R =7.5m=D If gunpowder specific gravity=0.83, minimum charge 11- (kg)=0.83XπX (r/2
×℃ =82.58kg Destruction bedrock 1! V (m') = 1/3T
tR2-1-1"843.75m" Risk rate or unit of rock destruction L/V =82. 58kg/843. 75m”=0,
0 98kg/m” ・・=−=・・=・(1) In addition to the above, the remaining drilling length H/2 = 1/3 of 7.5m, or 2.5m
If the charge amount is increased to (point .0m=Da Under the condition of gunpowder specific gravity=083, auxiliary i;! i drug amount La=0.83XiX (r/2)X
, 9a = 27.53 kg Destruction rock volume Va = 1/3π-Ra ” -1-1/2
=187.5m3 Hazard rate or tti broken rock unit L a / V a = 27
53/187.5 = 0. 15kg/m' ・・・・・・・−−(2)
The average risk rate or unit of rock mass failure in the whole (1) and (2) above] L / V + L a / V
a = 0.098 + 0.15 = 0.25 kg/m3, and either that value or the -radial fracture unit of rock mass is 0.25 to 0.
Since it is within the minimum range of 35, it is proven that it is safe.

Then, the remaining drilling length H/2 = 7.5, 215, or 3 m.
Assuming that the charge amount is increased to (point Xb), final fill length Da = 4.5 m, auxiliary charge amount 12a = 3.0 m (length from point X to point Xb), radius of fracture Ra = 4. 5m=Da Under the condition of gunpowder specific gravity 0.83, auxiliary charge fiLa=0.83X7(X (r/2)ff
a = 33.01kg Destruction rock volume V a = 1/3 x -Ra”
-) 1/2=151.87m” Hazard rate or unit of destruction rock mass L a / V a = 0.22
kg/m3 ・・・・・・・・・・・・・・・(3) Above (
Average risk rate for the whole including 1) and (3) or failure unit of rock mass L/V+La/Va=0.098+0.22=0.3
18 kg/m 3 , and the numerical value is 025 to 0
Since it is within the range of 35, it is safe.

As can be seen from the above examples, for example, the hole diameter r = 130
mm, drilling length 1-1 = 15 m, the safest standard value is the amount of charge at 2/3, or 10 m, from the bottom of the hole, and the amount of charge at 7/10, or lo, 5 m from the bottom of the hole. It is understood that this is the safest maximum value, and that charging more than that is dangerous due to flying stones, and it is impossible to proceed with the work safely.

g) Effects of the Invention As detailed above, in the present invention, the ratio of the amount of charge to the amount of destroyed rock, that is, the unit of destroyed rock (also known as risk rate or rupture coefficient) is within the range of 0.25 to 0.035 from experience. Based on this, we aimed to improve work efficiency by increasing the amount of charge as much as possible within the safe range. The value is 7/
Since we succeeded in quantitatively understanding the numerical values with the maximum length of It is now possible to easily, quickly and reliably determine the safest maximum charge amount on site. Therefore, since it is possible to carry out the blast using the maximum amount of charge within the safety limits that do not cause actual damage from flying stones, both safety and efficiency of the work can be achieved.

[Brief explanation of drawings]

FIG. 1 is an overall explanatory diagram showing the method for determining the safe maximum charge amount according to the present invention, and FIG.
FIG. 3 is an explanatory diagram illustrating the assumed state of rock destruction when blasting is limited to /2. FIG. 3 is a partial explanatory diagram when the auxiliary charge amount βa is added in FIG. 1. 1-((m) Drilling length, βfm) ... Minimum charge amount, ffa (m) ... Auxiliary charge amount, ε + 12 a[m:l ・ Maximum safe charge amount, D (r
rt)...Initial filling, 1) a (m)...R final filling length L (kg)
・・Minimum charge amount, La (kg)・・Supplementary charge amount, L×La (kg)・・・Safety maximum charge amount (final charge!, G, L・・Ground surface, V (m3)・・Minimum charge (1) Amount of fractured rock at L, R (m) ・ Fracture radius: initial charge D (rrt)
r (mm) ・Drilling diameter, m)...Standard value of safe maximum pharmaceutical amount, (m) Maximum value of safe maximum pharmaceutical amount, a (m3) Amount of broken rock at auxiliary charge amount La.

Claims (2)

[Claims] (1) The ratio of the amount of charge equivalent to 1/2 of the length from the bottom of the hole to the amount of fractured rock, that is, the unit of fractured rock is 0.08
A hole with a hole length and diameter within the range of ~0.11 is drilled, and 2/3 of the length from the bottom of the hole is set as the standard value.7/
1. A method for determining a safe maximum charge amount in perforation blasting, characterized by performing perforation blasting with a final charge amount within a range having a maximum value of 10. (2) The ratio of the final charge amount to the amount of rock destroyed, that is, the unit of rock destroyed (also known as risk rate or blasting coefficient) is 0.2
Claim 1 provided that it is within the range of 5 to 0.35.
The method for determining the safe maximum charge amount in perforation blasting as described.