KR20130062666A - Accurate directional blasting method using vibration control for reduction of vibration - Google Patents

Abstract

PURPOSE: An accurate blasting method of using a vibration control is provided to smoothly blast successively a blasting hole interval, a blasting porous dehiscence interval, and a block interval by selecting propriety time according to a quality and a kind of a rock. CONSTITUTION: An accurate blasting method of using a vibration control comprises the following steps: a blasting object ground is punched; a different delay time is given to a blasting hole interval which is successively blasted; a delay time is determined in consideration of a kind of rock and a quality of rock; and the delay time exceeds 8ms. The delay time of a blasting hole interval in a same blasting porous dehiscence is calculated with a following equation. D_hth=A×S in the formula above, the delay time(ms) of a blasting hole interval in a same blasting porous dehiscence is defined as D_hth. A gap(m) of a blasting hole interval in a same blasting porous dehiscence is defined as S. A is a constant determined according to a rock kind of a blasting object ground. A has a value of 0 (ms/m) to 5 (ms/m). [Reference numerals] (AA) Firing time(ms); (BB) Blasting hole; (CC) Direction of movement

Description

Accurate directional blasting method using vibration control for reduction of vibration}

The present invention relates to a blasting method, and more particularly, by selecting an appropriate initial time according to the quality and type of rock so that the blasted rock can move properly after blasting, sequentially between blasting holes, between blasting rows, and zones (Block). It relates to a precision vibration control blasting method, so that the blasting between) smoothly.

In general, blasting work is carried out for ground crushing, tunnel excavation, etc. at the construction and civil engineering site. The blasting work using explosives has the advantage of easily removing rocks or other obstacles using the explosive power of the explosives, but has the disadvantage that vibrations and noise generated during blasting affect the surrounding buildings or structures.

In the blasting process, the shock wave propagated from the width source is significantly attenuated according to the distance, but a part of the energy generated at this time is transformed into the form of an elastic wave and propagates into the rock to generate vibration of the ground. The ground vibration generated at this time is called blast vibration. These blasting vibrations have shorter durations, easier attenuation, and relatively simpler waveforms than vibrations caused by earthquakes. Therefore, in the workplace where open areas are formed, problems caused by blasting vibration hardly occur, but blasting vibration can cause serious problems when there are structures such as buildings, barns and subways in the vicinity.

In order to reduce the blasting vibration and noise, a method of sequentially blasting by giving a predetermined delay time without blasting the blasting holes has been proposed.

The blasting method has a constant (fixed) delay time between the blasting holes and the blasting holes that are sequentially blasted, for example, between two blasting holes 10 that are sequentially blasted in the direction of the arrow, as shown in FIG. Irrespective of the above, the fixed delay time t1 in MS units is given constantly, or the fixed delay time t1 in DS units is given constantly.

However, the blasting method has a problem in that vibration and noise cannot be optimally reduced because a fixed delay time t1 is fixed between the blasting holes 10. In other words, even in the same blasted ground, rock types (carcinoma) and rock quality may be different from each other, and rock types (carcinoma) and rock quality may be different between blast gaps and zones. If the fixed delay time t1 is given constantly, the vibration and noise cannot be reduced optimally.

The present invention has been devised to solve the above problems, by sequentially selecting the appropriate initial according to the quality and type of rock so that the blasted rock can move properly after blasting sequentially between the blast hole, between the blast pore, and the zone (Block) The purpose of the present invention is to provide a precision vibration control blasting method, such as to smooth the blasting between, and to be applied to open air, tunnels, vertical spheres and urban blasting.

The geological characteristics of the crushed material are the most important factors in determining the overall blasting design. There are a number of theories related to the speed of sound and rock hardness to determine the explosive ratio required for material fracture. In general, extensive field trials should be conducted to determine these factors. In most cases the test results are based on the assumption that the material to be shredded is homogeneous. The results from these tests can be used as a guideline when determining the spacing and resistance lines, the required charge rates, and the types of explosives. However, in the final analysis, decisions are usually made based on judgments trained on years or decades of experience.

Perforation rates are often used as a guide to determine rock hardness. This is not necessarily a good criterion for the difficulty of breaking up materials. In many cases, very hard brittle rocks are easier to blast than soft porous rocks. Stratification of rocks is a very important factor in blast design. When the strata consist of thinly divided horizontal rock layers, the rocks are destroyed with relatively large resistance lines, space spacing, and low charge ratios, and sufficient fracture rates can be obtained.

If the rock layers are massive and not thin, the resistance and spacing should be tight and the cost of the charges should be high. Under these conditions, the resistance and spacing should be reduced.

If the inherent crack planes are tightly spaced, the material will break more easily and use larger spaces.

Most of the rock layers are mainly broken by movement when the inherent crack surface is finely divided, and the radial crack generated when the fracture is broken is shifted at 0.15 to 0.4 times the stress wave velocity. This means that cracks can travel at speeds of 2,400 m / sec (0.4 x 6,000 m / sec) in dense masses. In the case of rocks with low wave propagation rates, cracks occur at 450 to 1250 m / sec. In short, the initial crack is well established within a few milliseconds, depending on the specification of the perforation pattern.

Extensive studies of rock movement mechanisms in the quarry have shown that the initial wall movement time depends primarily on the size of the resistance line in front of the ball. When the resistance line is 1.0m to 6.0m, the initial wall movement is within 15 milliseconds.

In addition, the rock crushing process occurs for a fairly short time (5 to 15 MS). But the migration process is completely different. In blasting, the crushed rock moves at a relatively slow speed of 15 to 30 m / sec. Most shredding, on the other hand, is completed in a few milliseconds and takes longer to exit. When the crushed rock moves at a speed of 15 to 30 m / sec, the crushed rock travels only 0.15 to 0.3 m in 10 milliseconds. This long travel time is an important part of the blast design to achieve the desired degree of crushing.

Therefore, even when blasting from a free surface, rock movement time is an important factor. This is especially true when blasting a large number of heat, where the initial movement in the free plane is made at 10-12 milliseconds, but the resistance line is only 15 cm at 10 milliseconds.

In the case of one or two blast gaps, the main movement is directly off the wall. As the number of rows increases, there is a tendency for the rock to move toward the vertical plane (free plane). This is due to the low velocity of the crushed rock, which reduces the relief towards the quarry walls. This causes not only the headstone but also the floor to be "filled", so in the process of designing the blasting in order to properly move the blasted rock after blasting according to the quality and type of rock, etc. It is the core of the present invention that the blasting between the blast holes, the blast holes, and the blast zone (Block) is smoothed.

You can also blast by increasing the delay in the last column by about twice the first column. This should allow the rock in front of the last row to move forward and allow more time for the relief in the last row to increase. This is called "skipping a period," which also reduces upward rupture and significantly reduces backbreak in the wall.

Therefore, the present invention is to set the appropriate initial so that it is not necessary to skip the first time skip, to reduce the vibration, noise and maximize the blasting efficiency. As an example, as shown in Fig. 2, the present invention provides a No. 1 method to provide additional time when the blasting is composed of nine rows, without skipping the beginning time. No. 1 in 8 periods (25 MS to 200 MS) provide 25 milliseconds between each period. 8 to No. 14 (200 MS to 500 MS) provides 50 milliseconds between each period. No. 19 at 14 (500 MS to 1,000 MS) provides 100 milliseconds between each period. In FIG. 2, the number described above each blasting hole means a time (ms) at which the blasting hole is blasted, and the number described below each blasting hole means a period number of the blasting hole. The arrow indicates the direction in which the blasted rock (ground) moves.

Even if additional time is given between the blast gaps, the rocks still tend to stack when the number of rows is excessive. The pore, resistance line, spacing, and height of the walls all have a significant impact on the number of heat that can be successfully blasted without excessively high rock stacks or high floors. When a rock is destroyed, its area (expansion coefficient) is increased by about 25 percent than in a single mass. But 25 percent is an average factor that can vary depending on the type of rock. In most cases, the material moves in only two directions: forward and vertical. Obviously, excessive movement in any direction creates dangerous monuments. Therefore, the movement is limited, and if the number of heat is excessive, it becomes impossible to secure additional space for expansion.

Therefore, each blasting must be designed to suit the existing environment and to produce the desired end result. It is impossible to design blasting for all conditions because the environment is different for each blasting and for each individual task.

In blasting multiple holes / rows, it is important to ensure adequate delay between sequential balls and / or rows. An appropriate delay must be established so that each blast can destroy the resistance wire in front of it and the crushed rock can move before the back ball detonates. As shown in FIG. 3A, if the space delay time is too short, the movement of the thermal resistance line is limited, resulting in excessive resistance in the second and subsequent columns, and the lack of relief tends to cause the rock to move vertically.

In addition, it is a cause of safety accidents due to bad crushing, dense piles, high noise, vibration, and stone monuments, as well as a backbreak along the new free surface, which impairs the stability of slopes and openings. Too long can result in a cutoff in the surface delay.

On the other hand, as shown in Figure 3b, by providing an appropriate delay time between the blast cavity can solve the above problems.

The minimum timing (minimum delay time) for the design depends on the stress wave travel to allow the radial cracks to begin to break out of the rock. This deviation creates an internal free surface (or relief), which then causes detonation to interact with the reflection of the stress wave. Therefore, the minimum timing is as follows.

Where t is the stress wave travel time (in ms).

B _e : Distance from effective resistance line or blast hole to free surface (unit m)

C = Propagation velocity for rock in m / sec

Optimal choosing is the timing at which the resistance wire is sufficiently isolated and gas pressure builds up. Resistance lines were found to move within a time range between 2 and 10 times the time the stress wave travels to the free plane. The time for the resistance line movement is about 5 to 50 ms, and the appropriate initial time is selected according to the rock quality to be blasted sequentially.

Of particular importance when choosing a space / hot delay time combination is the average time interval between sequential detonations. The space delay interval should allow the second blast hole row to begin detonation before the detonation of the first row is completed.

Therefore, the average hot delay time is in the range of 20 to 100 ms, and the spatial delay time is in the range of 10 to 50 ms, which may vary somewhat depending on the most suitable ultra time interval, rock characteristics, and ground conditions.

In the case of blasting using a general electric or non-electric primer, the ratio of delayed dispersion to the normal blasting time is found in most commercial primers. If there is a 10% variance over a 25 ms delay, the delay error will be ± 2.5 ms of error, but for 250 ms, the error will be ± 25 ms. Therefore, a large delay (> 500 ms) results in dispersion that can easily exceed the surface delay interval, facilitating simultaneous blast order reversal and ball detonation.

Therefore, in order to make full use of the blast energy of adjacent heat and to take advantage of the superposition effect of stress waves, it is necessary to select a much shorter initial time than in conventional blasting. However, care must be taken to find the free surface because the rock material in the previous row must move before the stress wave of the adjacent hole arrives, but the delay time between the blast hole and the blast hole was about 10-35 ms.

The blast design should take into account the presence of structural geological features, and the draft should be altered according to the thickness, direction, and characteristics of the rock layers in the rock as well as the characteristics of joints and faults.

Geological parameters include structural geology, cracks, jointing and faulting of rocks. However, practitioners encounter another powerful variable, which is the one that controls rock mechanics and its effect on blasting design.

Depending on the type of rock, some rules for the temporal control of short bursts between blasting holes are 5.5 ms / m for some limestones, rock salts, and some shales, 4.5 ms / m for limestone, marble, granite, basalt, quartzite, gneiss and gabbro, It is 3.5ms / m in rock, rock, gneiss, schist and sedimentary rocks.

The short time between the blasting gaps (interline) or the short time between the blasting zones can be obtained by the following equation.

In Equation (2)

t _r : delay time between blast holes or delay time between blast zones (ms)

T _R : Time factor between blasting gaps (ms / m) or time factor between blasting zones (ms / m), having a value of 8.5 ms or more and 16.5 ms or less per m resistance line.

B: length of resistance wire (m)

Here, it is preferable that T _R is 8.5 ms or more and 16.5 ms or less per m of resistance lines between blast gaps or between blast zones.

The shorter blow times result in higher rock piles, closer to free surfaces, more end brakes, and more explosion damage, storm pressure, and ground vibration. In addition, if the short time is short, there is a high possibility of tombstone there is a risk of a safety accident. Longer blow times result in lower ground vibration levels and less backbreak.

Therefore, the delay time for setting a single shot time to be used between columns or zones is shown in Table 1 below.

T _R (ms / m) result 6.5 Explosion damage, excessive storms, backbreaks, etc. 8.5 High piles of rock near free surface, normal storms, backbreaks 11.5 Average rock pile height, average storm and backbreak 16.5 Minimal backbreak and scattered rock piles

It is very important to apply the correct time, but it is preferable to use the differential primer and 10 to 50 time blast blasting machine of US Rio product because general primer can be difficult to apply on site due to product limitations.

When the dose is determined and the initial combination is adequate, there is a space for the rock body to expand between rows in the multiple row blasting.

In single row blasting, expansion is not a problem because the crushed rocks move into free space.

In multi-row blasting, rocks in front of the first heat blast hole will not be able to move enough before the second heat blast will hinder the movement of the crushed rock blasted in the second row.

When expansion is limited in this way, the particle velocity increases and the crushing efficiency decreases.

To ensure that the back row expands sufficiently, the first row needs to be loaded more than the dose calculated to meet the minimum resistance line. The delay in blasting is largely dependent on the primer's delay. Unfortunately, due to primer errors, planned delays are often not achieved in the field.

These errors mean that random human errors, institutional statistical errors, and regular errors can occur in the array.

In order to achieve the above object, the blasting method according to the present invention gives a different delay time between the blasting holes are sequentially blasted. The delay time is determined in consideration of at least the carcinoma and the quality of the blasted ground and exceeds 8 ms.

It is preferable that the delay time between two blast holes sequentially blasted satisfies the following equation.

In Equation (3)

D _hth : delay time (ms) between _{blast holes in the} same _{blast hole}

S: spacing between adjacent blasting holes in the same blasting space (m)

A: A constant determined according to the type of rock of the blasting ground, and has a value of 0 (ms / m) to 5 (ms / m). Specific values of A are shown in Table 2 below.

Space Delay Time Constant to Improve Fracture Degree Rock type A (ms / m) Some limestone, Rock Shale, some shale 4 to 5 Dense limestone, marble, some granite and basalt, quartz and some gneiss and gabbro 3 to 4 Whistles, whistling rocks, dense gneiss, mica schist and magnetite 2.5 to 3

When the blasting ground is granite, the delay time between the two blasting holes which are sequentially blasted is 15ms to 40ms, and when the blasting ground is the limestone, the delay time between the two blasting holes which is sequentially blasting is 20ms to 50ms. .

The delay time between the two blasting holes which are sequentially blasted when the target blasting ground is soft rock or soft rock is 10ms to 250ms, and between the two blasting holes which are sequentially blasted when the blasting target ground is normal or mid-hard rock The delay time is 20ms to 50ms and 50ms to 100ms in blasting rocks such as hard rock or extreme rock.

Classification Table of Integral Rock According to Uniaxial Compressive Strength of International Society for Rock Mechanics (ISRM) Rating Uniaxial Compressive Strength (MPa) Very high strength > 240 High strength 100-240 Medium strength 50-100 Moderate strength 25-50 Low strength 5-25 Very low strength 1 to 5

In the blasting method according to the present invention, the blasting between the blasting holes, the blasting rows, and the blocks is sequentially performed by selecting an appropriate initial time according to the quality and type of the rock so that the blasted rock can move properly after the blasting. Be sure to

1 is a block diagram showing a delay time given to the blasting hole in the delayed blasting method according to the prior art.
2 is a view showing an example of the blasting method according to the present invention, showing the blasting time and period of each blasting hole and the moving direction of the blasted ground.
3A is a cross-sectional view showing blasting results when insufficient space delay is given;
3B is a cross-sectional view showing blasting results when sufficient space delay is given;
4 and 5 are a plan view showing the blasting ground divided into a plurality of zones in order to give a different delay time to the blasting ground in accordance with the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only embodiments of the present invention and do not represent all of the technical idea of the present invention, various equivalents that may be substituted for them at the time of the present application It is to be understood that there may be variations and may be applicable to various blasting methods such as vertical spheres, open air, tunnels, and all primers.

Blasting causes various problems due to noise and vibration. In particular, ground vibrations caused by blasting are always a big problem, because it causes damage to adjacent buildings and inconveniences to residents. Therefore, the reduction or control of blast vibration is of great concern in most blasting sites.

Delayed blasting methods have been proposed to reduce blast vibration and noise. The conventional delayed blasting method sequentially blasts with a certain delay time between the blasting holes. In Korea, a fixed (constant) MS or DS unit delay time is provided between the blasting holes and the blasting holes.

On the other hand, the vibration wave generated in the blasting hole can control the blasting vibration by applying the appropriate delay time between the blasting hole and the blasting hole to reduce the maximum particle velocity of the ground vibration due to the overlapping wave at the specific point due to the interference of the interference wave. As a result, vibration and noise can be reduced.

Therefore, in order to control the blasting vibration, an appropriate delay time is variably given between the blasting hole, the blasting cavity, and the blasting zone according to the carcinoma and the cancer, and the blasting is carried out as much as possible. It is desirable to minimize the number of balls, divide the blast holes into more zones, and reduce the amount of charge per blast hole.

In the concept of optimal sequential delayed blasting according to the present invention, the blasting holes are sequentially blasted by giving a delay time between the blasting holes, and the delay time is variably determined in consideration of carcinoma and cancer.

While the conventional delayed blasting method gives a constant fixed delay time (for example, 20 ms units) to each primer, the present invention provides a variable delay time to each primer so that an arbitrary number of blasting holes (several tens) 700 holes) can be ignited. In order to blast with a lot of air of several tens to 700 holes in order to reduce the kinetic energy of the vibration or reduce the dominant frequency by reducing the maximum vibration speed or minimizing the correlation You must give the delay time to destroy the component.

In general, considering latency based solely on the requirement to reduce blast vibration interference in areas where security is present, the delay can be varied over a fairly broad range, from 1 ms to more than 1,000 ms. However, it is important to match this delay to rock type, rock quality, wave duration, and the like.

For example, according to the present invention, when the blasting ground is granite, an appropriate delay time between two blasting holes is sequentially about 15 ms to 40 ms, and when the blasting ground is limestone, an appropriate delay time is about 20 ms. To 50 ms.

In addition, the delay time between two blasting holes that are sequentially blasted when the blasting ground is soft rock or soft rock is 10ms to 250ms, and between the two blasting holes that are sequentially blasted when the blasting target ground is normal or mid-hard rock The delay time is 20ms to 50ms and 50ms to 100ms in blasting rocks such as hard rock or extreme rock.

In addition, to avoid mutual interference of the blasting vibration waves, it is necessary to make the delay interval exceed the period of the positive phase of the vibration wave.

On the other hand, Figures 4 and 5 shows that the blasting target ground divided into four blasting zones according to the present invention. The figure shows that the blasting ground is divided into four zones, but the number of blasting zones may be changed in consideration of the condition of the ground, carcinoma, and cancer.

When the 1st zone blasting ends and the 2nd zone blasting starts, it is appropriate to give a starting time of 8ms to 1000ms depending on the carcinoma and the rock quality, but it is arranged in the same way as the space second time space according to the number of blasting air.

It is appropriate to give a starting time of 8ms to 1000ms between the blasting zones when passing from zone 2 to zone 3 and zone 4 to zone 4, however, depending on the degree of blasting air, the delay time corresponding to each zone is the same. In some cases.

As described above, the blasting method according to the present invention divides the blasting ground into a plurality of zones in consideration of carcinoma, cancer quality, etc. and gives different delay time to each zone, thereby optimally reducing vibration and noise due to blasting. Can be.

10: blast hole t1: delay time

Claims (6)

A different blast time is given between the blasting holes perforated and sequentially blasted in the blasting ground, wherein the delay time is determined in consideration of at least the carcinoma and rock quality of the blasting ground, and the blasting method characterized in that it exceeds 8ms. The method of claim 1,
A blasting method characterized in that a delay time between blasting holes in the same blasting pore is obtained by the following equation.
D _hth = A × S
In the above equation,
D _hth : delay time (ms) between _{blast holes in the} same _{blast hole}
S: spacing between adjacent blasting holes in the same blasting space (m)
A: A constant determined according to the type of rock of the blasting ground, and has a value of 0 (ms / m) to 5 (ms / m). The method of claim 2,
When the rock type is some limestone, rock shale, and some shale, A has a value of 4 (ms / m) to 5 (ms / m), and the rock type is dense limestone, marble, some granite, basalt, and stone. In the case of Yeongam, some gneiss, and companion rock, A has a value of 3 (ms / m) to 4 (ms / m), and when the rock type is rock rock, whistling rock, dense gneiss, mica schist, and magnetite, Blasting method, characterized in that A has a value of 2.5 (ms / m) to 3 (ms / m). The method of claim 1,
When the blasting ground is granite, the delay time between the two blasting holes is sequentially 15ms to 40ms, and when the blasting ground is the limestone, the delay time between the two blasting holes is sequentially 20ms to 50ms. Blasting method characterized by. The method of claim 1,
Delay between two blasting holes that are sequentially blasted when the ground is soft rock or soft rock; 10ms to 250ms, and delay between two blasting holes that are sequentially blasted when the blasting ground is ordinary or cultivated cancer Blasting method, characterized in that the time is 20ms to 50ms and 50ms to 100ms in the case of hard or hard rock. The method according to any one of claims 1 to 5,
A blasting method characterized in that the delay time between the blast holes or the delay time between the blast zones is obtained by the following equation.
t _r = T _R × B
t _r : delay time between blast holes or delay time between blast zones (ms)
T _R : Time factor between blasting gaps (ms / m) or time factor between blasting zones (ms / m), having a value of 8.5 ms or more and 16.5 ms or less per m resistance line.
B: length of resistance wire (m)

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