CN113251881B - Test method for setting blasting delay time - Google Patents
Test method for setting blasting delay time Download PDFInfo
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- CN113251881B CN113251881B CN202110598204.XA CN202110598204A CN113251881B CN 113251881 B CN113251881 B CN 113251881B CN 202110598204 A CN202110598204 A CN 202110598204A CN 113251881 B CN113251881 B CN 113251881B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D3/00—Particular applications of blasting techniques
- F42D3/04—Particular applications of blasting techniques for rock blasting
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Abstract
A test method for setting blasting delay time belongs to the technical field of design blasting engineering and comprises the following steps: step 1, calculating the crushing radius of shock waves and the crushing radius of stress waves; step 2, selecting a pitch; step 3, putting equivalent explosives into the two blast holes; step 4, calculating the average speed; step 5, obtaining delay time; step 6, adjusting the pitch of holes; step 7, selecting the optimal hole distance a to obtain the optimal blasting delay time; and 8, detonating the explosive according to the obtained optimal blasting delay time. The invention establishes a relative relation with the properties of the explosive and the uniform medium through the measured explosive detonation velocity and the inherent property of the uniform medium to obtain the crushing radius of the shock wave and the crushing radius of the stress wave, and obtains the delay time according to the total propagation distance of the shock wave and the stress wave and the average speed of the shock wave and the stress wave.
Description
Technical Field
The invention belongs to the technical field of design blasting engineering, and particularly relates to a test method for setting blasting delay time.
Background
Blasting is an important process in the production process of mineral engineering and geotechnical engineering, and setting reasonable blasting delay time is an effective means for improving blasting quality and increasing mine production efficiency. The blasting delay time selection methods are various, most of the blasting delay time selection methods are theoretical researches, and the test methods also often use actual mines as backgrounds, so that the delay time of blasting of various explosives cannot be determined. Therefore, a convenient, universal and effective delay time setting test method is provided, and data are provided for researching the delay time of blasting of various explosives in the medium.
Disclosure of Invention
The invention aims to provide an efficient and convenient test method for setting the delay time of an explosive according to the physical properties of the explosive and a uniform medium by combining the addition of a free surface and a stress wave superposition theory.
The invention adopts the following technical scheme:
a test method for setting blasting delay time comprises the following steps:
step 1, calculating the crushing radius R of the shock wave according to the explosion velocity of the explosive, the charging radius and the physical properties of the uniform medium c And stress wave crushing radius R p ；
Step 2, selecting a hole distance a in a stress wave breaking radius theoretical value limit range, and setting a blast hole, wherein the hole distance range is as follows:
R p ＜a＜2R p
when the stress wave moves to a half part between the periphery of the crushing area of the first explosive package and the periphery of the fracture area of the later explosive package, the next explosive package is detonated;
step 3, putting equal-quantity explosives with the same type in the two blast holes;
step 4, calculating an average speed v according to the speed from the shock wave to the edge of the shock wave crushing area and the speed from the stress wave to a half position between the edge of the first explosive charge shock wave crushing area and the edge of the later explosive charge stress wave crushing area;
step 5, calculating the total propagation distance S of the shock wave and the stress wave according to the hole distance, the crushing radius of the shock wave of the explosive charge with the first explosion and the crushing radius of the stress wave of the explosive charge with the later explosion, and acquiring the delay time t according to the calculated total distance S and the average speed v;
a delay time t of
a is the pitch of the holes; r c Is the crushing radius of the shock wave; r p Is the stress wave breaking radius; rho s Is the density of the medium, E d Is the dynamic elastic modulus of the medium, mu d The dynamic Poisson ratio of the medium, D is the explosive detonation velocity;
step 6, repeating the steps, adjusting the hole pitch a, and recording the medium crushing effect and the crushed block crushing degree of the blasting medium after each blasting;
and 7, observing the crushing effect of the blasted medium and the crushing degree of the broken blocks of the blasted medium, and selecting the optimal hole distance a to obtain the optimal blasting delay time.
Further, in step 1, the shock wave pulverization radius R c Comprises the following steps:
ρ s is the density of the medium, E d Is the dynamic elastic modulus of the medium, mu d Dynamic Poisson's ratio of the medium, D is explosive detonation velocity, r b Is the radius of the blast hole, sigma c The rock compressive strength is shown, and rho is the explosive density;
stress wave breaking radius R p ：
r c Is the radius of charge, σ t The tensile strength of the rock.
Further, in step 4, the average velocity v is
Further, in step 5, the total propagation distance S between the shock wave and the stress wave is
Further, the method is to set the delay time of the explosive for the double-hole blasting test in the uniform medium.
The invention has the advantages and effects that:
the invention provides a test method for setting delay time, which combines the addition of a free surface and a stress wave superposition theory and calculates the delay time of an explosive according to the physical properties of the explosive and a medium. The test method provided by the invention has the advantages that the required data is easy to obtain, the test method is simple and convenient, and the optimal blasting effect of the explosive can be efficiently and conveniently obtained.
Drawings
FIG. 1 is a schematic flow chart of the method of the present invention.
Detailed Description
The invention is further explained below with reference to the figures and the examples.
As shown in figure 1, the invention relates to a method for setting blasting delay time, which calculates the crushing radius of shock waves, the crushing radius of stress waves, the velocity of shock waves and the velocity of stress waves according to the properties of explosives and media by combining a free surface increasing method and a stress wave superposition method, so as to obtain the blasting delay time.
The invention relates to a test method for obtaining delay time, which is characterized in that in uniform medium delay blasting, after a first explosive bag is detonated, a stress wave of the first explosive bag is continuously attenuated, when the stress wave reaches one half of the position between the periphery of a stress wave crushing area of a later explosive bag and the periphery of a shock wave crushing area of the first explosive bag, the next explosive bag is detonated, the pressure of the shock wave starts to be rapidly weakened after reaching a peak value, the first explosive bag provides enough free surface for the later explosive bag, and the stress wave generated by the later explosive bag is superposed with the stress wave of the first explosive bag in a medium, so that the number of medium cracks is further expanded and communicated, the medium crushing range is enlarged, and the medium is further crushed.
The method is a double-hole blasting test in a uniform medium, and the delay time of the explosive is calculated according to the explosion velocity of the explosive and the physical property of the uniform medium, so that the optimal blasting effect is obtained.
The invention relates to a method for setting blasting delay time, which comprises the following steps,
step 1, calculating a shock wave crushing radius and a stress wave crushing radius according to the explosive detonation velocity, the explosive charging radius and the physical properties of a uniform medium;
crushing radius R of shock wave c Comprises the following steps:
ρ s is the density of the medium, E d Is the dynamic elastic modulus of the medium, mu d Dynamic Poisson's ratio of the medium, D is explosive detonation velocity, r b Is the radius of the blast hole, sigma c The compressive strength of the rock;
stress wave breaking radius R p ：
r c Is the radius of charge, σ t The tensile strength of the rock;
and 2, selecting the hole pitch within the limit range of the theoretical value of the breaking radius of the stress wave, and setting the blast hole.
The pitch range is as follows:
R p ＜a＜2R p
when the stress wave moves to the half part between the periphery of the crushing area of the first explosive package and the periphery of the fracture area of the later explosive package, the next explosive package is detonated.
Step 3, putting equal-quantity explosives with the same type in the two blast holes;
step 4, calculating the total propagation distance S of the shock wave and the stress wave according to the hole distance, the crushing radius of the shock wave of the explosive charge with the first explosion and the crushing radius of the stress wave of the explosive charge with the second explosion
Calculating the average velocity v according to the velocity of the shock wave in the crushing area of the explosive charge with the first explosion and the velocity of the stress wave reaching the half part of the periphery of the crushing area of the explosive charge with the second explosion and the fracture area with the second explosion
Step 5, calculating the delay time t according to the total travel and the average speed of the propagation of the shock waves and the stress waves
And 6, repeating the steps, adjusting the hole distance a, and recording the medium crushing effect and the crushed block crushing degree of the blasting medium after each blasting.
And 7, observing the crushing effect of the medium after blasting and the crushing degree of the broken pieces of the blasting medium, selecting the optimal hole distance a, calculating the optimal blasting delay time, and obtaining the optimal blasting effect.
And 8, detonating the explosive according to the obtained optimal blasting delay time.
Example 1
According to the invention, the detonation velocity of the explosive, the crushing radius of the shock wave and the crushing radius of the stress wave are calculated according to the detonation velocity of the explosive and the physical properties of a uniform medium, and the method provided by the invention is combined to set the hole pitch for arranging blast holes for calculating the delay time.
Calculating the optimal delay time of the ammonium nitrate explosive with the charging radius of 30mm in the blasting of the uniform medium:
the detonation velocity D =3200m/s of the ammonium nitrate explosive, and the explosive density rho =1170kg/m 3 Radius of charge r c =30mm, blast hole radius r b ＝40mm。
Selecting a glass square as a uniform medium with the density rho s ＝2500kg/m 3 Dynamic modulus of elasticity E d =72Gpa, dynamic poisson ratio μ d =0.2, compressive strength σ c =120MPa, tensile Strength σ t ＝60MPa。
Calculating the crushing radius of the shock wave according to the formula (1)
R c ＝1.53m
Calculating the breaking radius of the stress wave according to the formula (2)
R p ＝12.32m。
Putting the same type of equivalent explosives into the two blast holes;
setting the hole distance a according to the method of the invention, and putting the same amount of explosive in the holes;
the pitch range is as follows:
R p ＜a＜2R p
a is 1.1R p ，a＝13.55m。
Calculating the total propagation distance S of the shock wave and the stress wave according to a formula (3);
S＝2.88m。
calculating the shock wave velocity and the stress wave velocity according to a formula (4), and calculating the average velocity v;
v＝2.87km/s。
calculating the delay time t of the explosive according to the formula (5)
T =1.003ms was calculated.
Repeating the above steps, adjusting the pitch a to be 0.2R away from the previous step p And (4) arranging hole distances at intervals, and recording the medium crushing effect and the broken degree of blasting medium fragments after each blasting.
According to the crushing effect of the medium after blasting and the crushing degree of the broken pieces of the blasting medium, when a is 1.5R p ，a＝1848m, delay time t =2.68ms, explosive density ρ =1170kg/m3, charge radius r c Radius r of nitramon explosive of =30mm in blast hole b The best blasting effect is achieved in 40mm glass medium.
Claims (5)
1. A test method for setting blasting delay time is characterized in that: comprises the following steps of (a) carrying out,
step 1, calculating the crushing radius R of the shock wave according to the detonation velocity of the explosive, the charging radius and the physical properties of the uniform medium c And stress wave crushing radius R p ；
Step 2, selecting a hole distance a within the limit range of the theoretical value of the breaking radius of the stress wave, and setting a blast hole;
pitch range:
R p ＜a＜2R p
when the stress wave moves to a half part between the periphery of the crushing area of the first explosive package and the periphery of the fracture area of the later explosive package, the next explosive package is detonated;
step 3, putting equal-quantity explosives with the same type in the two blast holes;
step 4, calculating an average speed v according to the speed from the shock wave to the edge of the shock wave crushing area and the speed from the stress wave to the half position between the edge of the shock wave crushing area of the explosive charge of the first explosive charge and the edge of the stress wave crushing area of the explosive charge of the later explosive charge;
step 5, calculating the total propagation distance S of the shock wave and the stress wave according to the hole distance, the crushing radius of the shock wave of the explosive charge with the first explosion and the crushing radius of the stress wave of the explosive charge with the later explosion, and acquiring the delay time t according to the calculated total distance S and the average speed v;
a delay time t of
a is the pitch of the holes; r c Is the crushing radius of the shock wave; r p Is the stress wave breaking radius; ρ is a unit of a gradient s Is the density of the medium, E d Is the dynamic elastic modulus of the medium, mu d Dynamic Poisson's ratio as a medium, D is fryingThe explosive explosion speed;
step 6, repeating the steps, adjusting the hole pitch a, and recording the medium crushing effect and the crushed block crushing degree of the blasting medium after each blasting;
and 7, observing the crushing effect of the blasted medium and the crushing degree of the broken blocks of the blasted medium, and selecting the optimal hole distance a to obtain the optimal blasting delay time.
2. A test method for setting blast delay time according to claim 1, wherein: in the step (1), the raw material is processed,
crushing radius R of shock wave c Comprises the following steps:
ρ s is the density of the medium, E d Is the dynamic elastic modulus of the medium, mu d Dynamic Poisson's ratio of the medium, D is explosive detonation velocity, r b Is the radius of the blast hole, sigma c The rock compressive strength is shown, and rho is the explosive density;
stress wave breaking radius R p ：
r c Is the radius of charge, σ t The tensile strength of the rock.
3. A test method for setting blast delay time according to claim 1, wherein: in step 4, the average velocity v is
4. A test method for setting blast delay time according to claim 1, wherein: in step 5, the total propagation distance S between the shock wave and the stress wave is
5. A test method for setting delay time of blasting according to claim 1, wherein: the method is to set the delay time of the explosive in the double-hole blasting test in a uniform medium.
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| CN109029177A (en) * | 2018-08-30 | 2018-12-18 | 西北矿冶研究院 | Blasting method for access type stoping |
| CN109682697A (en) * | 2019-01-17 | 2019-04-26 | 北京信息科技大学 | A method of measurement column charing is in rock interior blast action region |
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| WO2016047812A1 (en) * | 2014-09-23 | 2016-03-31 | In Mu Ryu | Method of the shortest inter-hole delay blast and the blasting and delaying means |
| CN105223331A (en) * | 2015-09-01 | 2016-01-06 | 鞍钢集团矿业公司 | A kind of rock mates preferred explosion bulge test method with explosive |
| CN109029177A (en) * | 2018-08-30 | 2018-12-18 | 西北矿冶研究院 | Blasting method for access type stoping |
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