JPH04106400A - Determining method of amount of safety charge in drillhole blasting - Google Patents

Abstract

PURPOSE:To permit the prevention of stone flying accident by a method wherein the operating formula of amount of blasting charge is covered by the dividing of divisions, which is effected by the chief of charging, and the summerizing of the units of blasting rock per one division to determine the amount of safety charge with a high accuracy. CONSTITUTION:When an arbitrary drilling diameter R (mm), a drilling length h (m) and the radius of demolition r (m) are determined, the minimum resistant wire W is deemed to W=r and the number of division N, obtained by dividing the drilling length h (m) by the drilling diameter R (mm), is deemed so that N=h/R, the amount of charge per one division Ln=L/N, the amount of rock per one division Vn=1/3.pi.r<2>.W or Vn=1/3.pi.W<3> in this case since W=r, and a blasting rock unit Cn=Ln/Vn per one division are obtained from the formula of the total amount of charge L=pi(R/2)<2>XhX0.83 of specific gravity of the charge. The summerizing value C of respective division blasting rock units Cn, operated by difining the deepest position of the drilling length (h) as the value of zero, is obtained sequentially in such a manner while the amount of charge within a specified range in respective summerizing values C is determined as a safety value Respective summerizing values C are recognized as a safety reference value when it is 0.25 and are recognized as a safety limit value when it is 0.35 while the same values C are recognized as a dangerous value when it is 0.45.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for determining an effective safe charge amount when destroying rock by drilling and blasting.

[Prior Art] Conventionally, Hauser's formula, namely, charge amount L (kg) = blasting coefficient C x minimum resistance line W3, is well known as a calculation formula for determining the amount of charge for blasting. This formula is the formula V for calculating the volume of a cone.
(m''): 1/3XiXr''Xh is a modification, and if both r and h are replaced with W, Hauser's formula will be realized.

[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 O 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 there is no gunpowder with a charge volume of 0 or 1 force; As long as it existed, it was impossible to use Hauser's formula to accurately calculate the amount of charge, especially the maximum safe amount without the risk of flying stones.

The purpose of this invention is to rationally calculate the huge volume of explosives that occurs when charging during actual drilling and blasting, and to easily determine the safe amount of explosives that is the two-fold limit that does not cause actual damage from flying stones. The goal is to provide a way to obtain

[Means for solving the problem] First, any perforation diameter R (+nm) and perforation length h (ml
Determine the fracture radius r (m), consider the minimum resistance line W = r, the number of sections obtained by dividing the hole length h (m) by the hole diameter R (mm), and the total charge amount L : π(R/2)2×h×Gunpowder specific gravity 0.83, the amount of charge per division L n = L / N.

Amount of rock mass per section V n = 1/3・π・r”
-W Here, since r=W, find Vn, W3, and the fractured rock unit per section Cn = L n / V n.

In this way, the cumulative value C of each segmental fractured rock unit Cn is determined sequentially, with the innermost end of the drilling length being set as 0 value, and the charge amount within a specific range for each cumulative value C is determined as a safe value. .

The cumulative total of each of the above (IIC is 0.25 as the safety standard value, 0°3
Recognize 5 as a safe limit value and 0.45 as a dangerous value.

[Function] Taking advantage of the characteristic that the accuracy of Hauser's formula is guaranteed when the position of the charge is set to one minimum point, as described above, in the present invention, the accuracy of Hauser's formula is guaranteed. The drug hole is divided into units based on the hole diameter R, and the unit of fractured rock Cn for each division is sequentially calculated.

Destruction rock mass unit C for each category obtained in this way
The innermost end of the drilling length is taken as the O value, and the values of n are sequentially added to obtain the cumulative value C. From the state of the cumulative value C, the safe value range is determined, and the dividing position of the drilling length indicated by this value is determined. is determined as the safe charge amount.

[Example] As shown in the drawing, the hole diameter R = 25 (++++n), the hole length h = 1,5 (m
l, gunpowder specific gravity 083. When minimum resistance mw = fracture radius r, number of sections N = h/R = 1.510.025 = 60 (pieces) Total charge L; π (R/2)" x h x gunpowder specific gravity = π (0 ，
025/2)" x 1.5xO183 = 0.61.5 (kg) Charge amount per category L n = L / N 20.61.5 (kg) /60 (pieces) = 0.01
．． 025 (kg/piece) Amount of rock destroyed per section V n = 1 / 3 ・w ・W 3miW” (m”
/ unit) Destruction rock unit per section Cn = L n / V n = 0.01025 (kg) /W'' (m31).

So, first of all, Mogami J-! The numerical values of the specifications in li (class No. 1) are as follows. That is, the charging amount L of classification No. 1 is =0. Ol 025 (kg) = C, (0
,025)" The unit of rock mass to be destroyed = 82 Category No., the charge weight of 40,...,0.01025 = (4,x (1,00) The unit of rock mass to be destroyed C4゜:=Q,01025 In this way , The charge amount L 80 of the lowest division N060 is L6.=0.0
1025 = CsoX (1, 5) 3 Destruction rock unit = 656 Classification No. 2 charge amount L* = 0. 01025 (kg) = C,

The above situation is The details are shown in Table 1.

As is clear from the description in Table 1, for example, the safety standard value C = 0.25 is found to exist between the number of divisions N = 31 and 32 (see *1), so the charge length is 72 cm. It is estimated that the Next, since the safety limit value C=0.35 corresponds to the number of sections N=28 (see *2), it is estimated that the charge length is 80 cm. Also, the danger value C=
Since 0.45 corresponds to the number of divisions N=25 (see *3), it is estimated that the charge length is 87.5 cm.

[Effects of the Invention] As detailed above, the present invention solves the weaknesses of the conventionally well-known formula for calculating the amount of blasting powder L = CW' by dividing the charge length and
Covered by cumulative totaling of fractured rock units per category,
Since the safe charge amount can be determined with high accuracy based on the calculation formula L=CW, it is now possible to prevent flying stone accidents.

[Brief explanation of drawings]

The drawing is an explanatory diagram illustrating a method for determining a safe charge amount according to the present invention.

Claims (2)

[Claims] (1) First, any perforation diameter R (mm) and perforation length h (m)
and the fracture radius r (m), the minimum resistance line W = r, the number of divisions obtained by dividing the hole length h (m) by the hole diameter R (mm), and the total charge amount. From L = π (R/2)^2 x h x specific gravity of gunpowder 0.83, the amount of charge per section Ln = L/N and the amount of rock destroyed per section Vn = 1/3・π・r^2・W
Here, since r=W, Vn≒W^3 and the fractured rock unit per section Cn=Ln/Vn are determined, and thus each of the above sections with the innermost end of the drilling length h set as 0 value. A method for determining a safe charge amount in drilling and blasting, comprising: sequentially determining the cumulative value C of the per unit fractured rock mass Cn, and determining a charge amount within a specific range for each of the cumulative values C as a safe value. (2) The method for determining a safe charge amount in drilling and blasting according to claim 1, wherein C=0.25 is recognized as a safety standard value, C=0.35 as a safety limit value, and C=0.45 as a dangerous value.