JP2017032162A - Blast construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blast construction method capable of effectively reducing noise.SOLUTION: A blast construction method comprises a dividing step for dividing a target area A to be blasted into a plurality of divided areas A1, A2 and a blasting step for detonating a detonator for every area to perform a stepwise blasting. At the blasting step, a first stepwise blasting at the first divided area is carried out, a second stepwise blasting at the second divided area in such a way that a detonation time is not overlapped on that of the first stepwise blasting subsequent to the first stepwise blasting and an interval between a last blasting timing at the first stepwise blasting and an initial blasting timing at the second stepwise blasting is set to be longer than that of the detonation time of the first stepwise blasting.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a blasting method.

  As a blasting method, as described in Patent Documents 1 and 2, a technique for performing staged blasting at the face of a tunnel is known. In the blasting system described in Patent Document 1, an electric detonator is used, and the delay time of the electric detonator is set to be larger than the transmission time width. Further, a plurality of electron detonators connected to different output terminals of the branch box are detonated at different times. In the blasting method described in Patent Document 2, a charge hole is provided at a predetermined interval along the circumferential direction on the outermost periphery of the face, and a hole that is not charged is provided between the charge holes. . And the blasting of the charge hole is performed.

JP 2013-092274 A JP 2009-228977 A

  In order to crush the blasting target area such as the face of a tunnel by staged blasting, a certain amount of simultaneous drug is required. However, since the amount of the simultaneous drug affects the noise level, the noise cannot be reduced if the amount of the simultaneous drug is maintained above a certain level. From such a background, it has been difficult to effectively reduce noise in the blasting method using step blasting.

  An object of this invention is to provide the blasting method which can reduce noise effectively.

  The blasting method of the present invention includes a dividing step of dividing a blasting target region into a plurality of divided areas, and a blasting step of detonating a detonator for each divided area to perform staged blasting. In the blasting step, the first division First stage blasting in the area, followed by the first stage blasting, the second stage blasting in the second divided area so that the explosion time does not overlap with the first stage blasting, and the first stage blasting An interval between the last initiation timing in the first stage and the first initiation timing in the second stage blasting is set longer than the length of the initiation time of the first stage blasting.

  According to this blasting method, the blasting target area is divided, and the first stage blasting and the second stage blasting are performed individually so as not to overlap. By dividing the staged blasting and performing each separately, the peak value of the noise level in one staged blasting can be kept low while ensuring a certain amount of simultaneous drug. Moreover, since these intervals are set longer than the duration of the first stage blasting explosion, the influence of noise due to the first stage blasting is considerably reduced before the second stage blasting is started. Therefore, noise can be effectively reduced.

  The blasting target area is a face in tunnel excavation, and in the dividing step, the face may be divided into a plurality of divided areas adjacent in the left-right direction. In this case, noise generated during blasting of the face can be effectively reduced. Moreover, since the division area is set by dividing in the left-right direction, the fragmented pieces of the division area crushed by a certain stage blasting fall down and interfere with the divided area where the next stage blasting is performed. Hateful. Therefore, it is difficult to have an adverse effect on the next stage blasting.

  In the division process, the face is divided into three division areas, the central area in the center in the left-right direction and the left and right areas located on the left and right of the central area. In the blasting process, the central stage blasting in the central area is performed. The first stage blasting may be performed, and either the left stage blasting in the left area and the right stage blasting in the right area or both may be performed as the second stage blasting after the central stage blasting. In this case, both the central stage blasting, the left stage blasting and / or the right stage blasting can be suitably performed without any trouble.

  The interval between the first stage blasting and the second stage blasting may be 20 times or less the length of the first stage blasting detonation time. In this case, the influence of noise due to the first stage blasting can be more reliably reduced before the second stage blasting is started.

  The interval between the first stage blasting and the second stage blasting may be 10 times or less the length of the initiation time of the first stage blasting. In this case, the influence of noise due to the first stage blasting can be reduced before the second stage blasting is started, and the total initiation time can be shortened.

  According to the present invention, noise can be effectively reduced.

It is a mimetic diagram showing a tunnel excavation field where a blasting method concerning one embodiment of the present invention was applied. It is a front view which shows the example of arrangement | positioning of the initiation hole in the face in FIG. It is sectional drawing which shows the loading condition of the explosive in a detonation hole. It is a figure for demonstrating the detonation time of multiple times stage blasting, and those intervals. It is a front view which shows the face when the 1st step blasting is complete | finished. It is a front view which shows the other example of a setting of the division area in a face. (A)-(c) is a front view which shows the further another example of a setting of the division area in a face. It is a figure which shows the time change of the noise level in the Example performed using the electronic detonator. It is a figure which shows the time change of the noise level in the comparative example performed using the electric detonator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

  As shown in FIG. 1, the blasting method according to the present embodiment is a method applied to tunnel excavation for the stratum X made of hard rock. Tunnel excavation proceeds in the direction of the arrow shown (right direction in FIG. 1). In this blasting method, when tunnel excavation is performed, noise generated at a predetermined point S located around the tunnel TNL (for example, on the light side from the wellhead M) is reduced.

  As shown in FIG. 2, when performing blasting, a plurality of initiation holes 10 are provided in the face A that is a blasting target region. The plurality of initiation holes 10 form a plurality of initiation hole groups B <b> 1 to B <b> 6 and C <b> 2 to C <b> 6 for performing staged blasting at the face A. The arrangement pattern of the initiation holes 10 shown in FIG. 2 is merely an example, and the number and arrangement pattern can be changed as appropriate. The number and arrangement of the plurality of initiation holes 10 can be determined based on a known method in consideration of divided areas (details will be described later) uniquely set in the present embodiment.

  In the blasting method of the present embodiment, the face A is divided into a plurality of divided areas. Then, step blasting is performed for each divided area, and a predetermined time interval (that is, an interval) is provided between each step blasting. This is set so that noise generated at the stage blasting for each divided area (noise generated at the predetermined point S) is less likely to affect each other by providing an interval while securing a certain amount of the simultaneous drug in the stage blasting. doing. In the present embodiment, the concept including the number of the initiation holes 10, the arrangement pattern, and the time interval between the stage blasting is referred to as “division pattern”.

  As shown in FIG. 3, each detonation hole 10 includes, for example, a plurality of explosives (so-called increase die) 12 disposed in the hole 11, and detonators 13 provided on the back-side explosive (so-called parent die) 12. And a container 14 provided on the front side of the explosive 12. In the blasting method of the present embodiment, an electronic detonator capable of setting the detonation second in 1 ms units is used as the detonator 13. In the electronic detonator, the time difference between the detonation seconds is set by an electronic timer using an IC chip in the tube. This electronic detonator has high coincidence and has a function that allows the setting of the detonation second time to be arbitrarily changed and set at the face A according to the work performed at the face A. In this electronic detonator, for example, in the range of 1 ms to 30 ms, it is possible to set the time difference between the initiation seconds in units of 1 ms.

  In the electronic detonator, a delay time of up to 20 seconds can be set from when a signal is input (transmitted) to when it is detonated. By adopting the electronic detonator, the initiation time (initiation timing) can be set finely and accurately for each initiation hole 10. In particular, in the blasting method of the present embodiment in which a divided area is set on the face A, the single blasting time (total initiation time) at the face A is less than 20 seconds, and may be less than 10 seconds. is there. That is, all the stage blasts are started after the signals reach the IC chips installed in all the initiation holes 10. Stage blasting in one divided area does not adversely affect stage blasting in another divided area. Furthermore, according to the electron detonator, the sound pressure level of the low frequency sound generated by the stage blasting can be controlled, and as a result, the noise generated at the predetermined point S can be reduced.

  On the other hand, an electric detonator has also been used for blasting. In electric detonators, the blast time is set by the delay agent in the tube. As an electrical detonator, for example, a DS detonator with a time interval of 250 ms and an MS detonator with a time interval of 25 ms are known. Since electrical detonators use time delay drugs, the actual time interval may vary greatly from the set time interval. In this case, the seconds of the current initiation hole and the next initiation hole may overlap. Therefore, the electric detonator has low coincidence. In addition, the electric detonator has a larger time difference between the detonation seconds than the electronic detonator and can only set a delay time of less than 10 seconds. Therefore, after the blasting and blasting in a certain divided area is completed, the ignition is started to the initiation hole 10 in the other divided area. At that time, there is a possibility that the conducting wire (leg wire) is disconnected under the influence of the step-by-step blasting performed previously. In that case, step-by-step blasting in other divided areas becomes impossible. In consideration of such circumstances, it is preferable to use the above-described electronic detonator in the blasting method of the present embodiment in which a divided area is set on the face A.

  Then, the procedure of the blasting method of this embodiment is demonstrated, referring FIG. 2 and FIG. First, the face A that is a blasting target area is divided into a plurality of divided areas (dividing step). In other words, a plurality of divided areas are set for the face A. Here, the plurality of divided areas are set to be adjacent in the left-right direction (lateral direction). As shown in FIG. 2, a dividing line L extending in the vertical direction (vertical direction) is set in the approximate center of the face A, and one side (for example, the left side in the drawing) of the dividing line L is a first dividing area A1. The other side of the dividing line L (for example, the right side in the figure) is set as the second dividing area A2. The size of the first divided area A1 and the second divided area A2 may be the same, for example, but may be different. The shapes of the first divided area A1 and the second divided area A2 may be axisymmetric with respect to the dividing line L by providing the dividing line L at the center of the face A, but are asymmetric with respect to the dividing line L. There may be.

  In the first divided area A1, a plurality of initiation hole groups B1 to B6 are provided. In the second divided area A2, a plurality of initiation hole groups C2 to C6 are provided. The plurality of detonation hole groups B1 to B6 in the first divided area A1 are set so as to perform step blasting with a predetermined detonation time difference. The plurality of detonation hole groups C2 to C6 in the second divided area A2 are set to perform step blasting at a predetermined detonation second time difference. Two-stage blasting (first-stage blasting) in the first divided area A1 is performed first, followed by two-stage blasting (second-stage blasting) in the second divided area A2. Set the blast blast. In the first stage blasting and the second stage blasting, the detonation time of the detonator 13 in each detonation hole 10 of the detonation hole groups B1 to B6 and C2 to C6 is set so that the detonation times do not overlap.

As shown in FIG. 3, for the first stage onset blasting in the first divided area A1, and set the detonator seconds time difference Delta] t _1, for the second stage onset blasting in the second divided area A2, detonating second time difference Delta] t ₂ Set. The initiation second time difference Δt ₁ and the initiation second time difference Δt ₂ may be the same or different from each other. Explosion-second time differences Δt ₁ and Δt ₂ can be appropriately set, for example, within a range of 5 to 30 ms. For example, 17 ms may be adopted as the explosive second time differences Δt ₁ and Δt ₂ as suitable for reducing noise and vibration.

The numerical value obtained by multiplying the initiation time difference Δt ₁ by the number of the initiation holes 10 substantially corresponds to the initiation time (ΣΔt ₁ ) of the first stage blasting, and the numerical value obtained by multiplying the initiation time difference Δt ₂ by the number of the initiation holes 10 This roughly corresponds to the initiation time (ΣΔt ₂ ) for two-stage blasting. The initiation time for the first stage blasting (ΣΔt ₁ ) and the initiation time for the second stage blasting (ΣΔt ₂ ) may be the same or different from each other. The initiation time (ΣΔt ₁ ) of the first stage blasting and the initiation time (ΣΔt ₂ ) of the second stage blasting differ depending on the initiation second time differences Δt ₁ and Δt ₂ and the number of the initiation holes 10, for example, 0 .3 to 1.2 seconds. For example, when the initiation time difference Δt ₁ is 17 ms and the number of initiation holes 10 of the face A is 40, the initiation time of the first divided area A1 is about 0.7 seconds.

Further, the interval between the last initiation timing in the first stage blasting and the first initiation timing in the second stage blasting is set to be longer than the length of the initiation time of the first stage blasting. That is, as shown in FIG. 3, the interval ΔT is longer than the sum ΣΔt ₁ of the initiation time difference. The formula ΣΔt ₁ <ΔT holds. In the blasting method according to the present embodiment, the step blasting for each divided area is thus provided with an interval. Thereby, after the influence of the noise by 1st stage blasting is reduced significantly, 2nd stage blasting is started. Therefore, noise is effectively reduced.

  A specific method for determining the interval ΔT will be described. By increasing the interval ΔT between the first stage blasting and the second stage blasting, it is possible to reduce the influence of noise due to the first stage blasting, but if the interval ΔT is made too long, the face A Increases the total detonation time (total detonation time) required for one blast. A suitable interval ΔT may be set in consideration of these balances.

Regarding the upper limit of the interval ΔT, the interval ΔT between the first stage blasting and the second stage blasting is longer than the length of the first stage blasting initiation time (ΣΔt ₁ ) and 20 times the length. Set to less than double. The interval ΔT between the first-stage blasting and the second-stage blasting may be set to be 10 times or less the length of the first-stage blasting initiation time (ΣΔt ₁ ). For example, the interval ΔT is about 3 to 7 seconds. By providing such an interval ΔT, the influence of noise due to the first stage blasting can be more reliably reduced before the second stage blasting is started. When the interval ΔT is set so as to be not more than 10 times the duration (ΣΔt ₁ ) of the first stage blasting explosion time, the total initiation time can be shortened. Note that the interval ΔT between the first stage blasting and the second stage blasting may be set to be not more than five times the initiation time (ΣΔt ₁ ) of the first stage blasting.

Regarding the lower limit value of the interval ΔT, it is possible to apply a concept based on the length of the explosion time (ΣΔt ₁ ) of the first stage blasting. The interval ΔT between the first stage blasting and the second stage blasting may be set longer than the length of the first stage blasting detonation time (ΣΔt ₁ × 1). It may be set longer than 1.5 times or twice as long as the explosion time of step blasting (ΣΔt ₁ ). The interval ΔT between the first stage blasting and the second stage blasting may be set longer than five times the initiation time (ΣΔt ₁ ) of the first stage blasting.

The time difference between the initiation seconds may be set for each initiation hole 10 or may be set for every two or more initiation holes 10. That is, when an initiation second time difference is set for each initiation hole 10, the numerical value obtained by multiplying the initiation second time difference Δt ₁ , Δt ₂ by the number of the initiation holes 10 is the initiation time (ΣΔt ₁ , ΣΔt ₂ ) For example, when two detonation holes 10 are detonated at the same time, one-half of the numerical value obtained by multiplying the detonation time difference Δt ₁ , Δt ₂ by the number of detonation holes 10 is the step blasting. Generally corresponds to the initiation time (ΣΔt ₁ , ΣΔt ₂ ).

As shown in FIGS. 2 and 4, when performing two-stage blasting, that is, first-stage blasting and second-stage blasting, the total initiation time T _total required for one blast of face A is: For example, it is less than 10 seconds. The total initiation time T _total may be less than 7 seconds or less than 5 seconds by reducing the interval ΔT while satisfying the relationship between the above-described initiation second time difference Δt ₁ and the interval ΔT.

Then, the detonator 13 is detonated for each divided area A1, A2 with the explosive second time differences Δt ₁ , Δt ₂ and the interval ΔT set for the first divided area A1 and the second divided area A2, and the first stage blasting is performed. And the second stage blasting is performed sequentially (blasting process).

  Then, the above blasting process is repeated to advance tunnel excavation. While the tunnel excavation proceeds, the division pattern may be changed according to the condition of the rock and the position of the face A. While blasting is performed with a predetermined division pattern, the division pattern of blasting to be performed continuously is determined according to the sound pressure level of the low frequency sound at the predetermined point S (that is, the sound pressure level of the low frequency range of the blasting sound). In this case, the “low frequency range” may be a frequency of 100 Hz or less or a frequency of 80 Hz or less. The “low frequency range” may be a frequency of 50 Hz or less.

According to the blasting method of the present embodiment, the blasting target area is divided, and the first stage blasting and the second stage blasting are performed individually so as not to overlap. By dividing the staged blasting and performing each separately, the peak value of the noise level in one staged blasting can be kept low while ensuring a certain amount of simultaneous drug. In addition, since these intervals ΔT are set longer than the duration of the first stage blasting explosion (ΣΔt ₁ ), the influence of noise due to the first stage blasting is considerably reduced before the second stage blasting. Blasting begins. Therefore, noise is effectively reduced.

  The blasting target area is the face A in tunnel excavation, and in the dividing step, the face A is divided into a plurality of divided areas A1 and A2 adjacent in the left-right direction, so that noise generated in blasting the face A is effectively reduced. . Furthermore, as shown in FIG. 5, since the divided areas A1 and A2 are set by dividing in the left-right direction, the fragmented pieces of the first divided area A1 crushed by the first stage blasting fall downward. In addition, it is difficult to interfere with the second divided area A2 where the second blasting is performed. Therefore, it is difficult to adversely affect the second blast.

  In addition, a free surface is formed at a position corresponding to the dividing line L by the first stage blasting. In this way, since the blast timing is divided using the dividing line L as a boundary line (boundary surface) and the second stage blasting is performed with the free surface formed, the second stage blasting can be suitably performed. it can.

In the above-described embodiment, the example in which the blasting of the face A is performed in two parts has been described, but the present invention is not limited to two parts. In the case of dividing an area into three or more divisions, the relationship between the above-mentioned initiation second time difference Δt ₁ and the interval ΔT should be satisfied for any two stage blasting or all stage blasting performed at intervals. .

  For example, as shown in FIG. 6, even if the face A is divided into three divided areas, that is, a central area A1 in the center in the left-right direction, and a left area A2 and a right area A3 that are respectively located on the left and right of the central area Good. In the face A, two division lines L1 and L2 extending in the vertical direction (longitudinal direction) can be set. A plurality of initiation hole groups B1 to B4 are provided in the central area A1, a plurality of initiation hole groups C1 to C4 are provided in the left area A2, and a plurality of initiation hole groups D1 to D4 are provided in the right area A3. .

  In the blasting process, the central stage blasting in the central area A1 is performed as the first stage blasting, and either the left stage blasting in the left area A2 or the right stage blasting in the right area A3 following the central stage blasting. One or both are performed as a second stage blast. According to such a blasting method, the center stage blasting, the left stage blasting and / or the right stage blasting can be suitably performed without any trouble. Since the divided areas A1, A2, and A3 are set by dividing in the left and right direction, the fragment pieces of the divided areas A1 and A2 crushed by a certain stage blasting fall down and the next stage blasting is performed. It is difficult to interfere with the divided areas A2 and A3.

  The division pattern of the face A is not limited to the above-described two-division or three-division mode. For example, as shown in FIG. 7 (a), a four-divided configuration arranged in the horizontal direction may be adopted. In this case, the stage blasting of the first central area A11 and the second center area A12 closer to the center is sequentially performed. Subsequently, either the left stage blasting in the left area A13 or the right stage blasting in the right area A14 is performed. Do one or both. A predetermined time interval is provided between any stage blasts.

  Further, the division pattern is not limited to the aspect of dividing in the left-right direction. For example, as shown in FIG. 7 (b), a lower right divided area A21 and an upper left divided area A22 are provided toward the face A, and the divided blasting of the divided area A21 and the divided blasting of the divided area A22 are performed. May be performed sequentially. As shown in FIG. 7C, a divided area A31 at the center of the face A, an outer divided area A32, and an outermost divided area A33 are provided, and each stage of the divided areas A31, A32, A33 is provided. Blasting and blasting may be performed sequentially. A predetermined time interval is provided between any of the above-described stage blasts. Increasing the number of divisions increases the free surface formed during staged blasting, making it easy to crush the rock in the blasting target area such as face A.

  Although one embodiment of the present invention has been described, the present invention is not limited to the above embodiment. For example, the present invention is not limited to tunnel excavation but can be applied to other blasting works. For example, the present invention may be applied to light construction. The point where noise is reduced is not limited to the light side of the wellhead, and may be a point above the tunnel TNL. The first stage blasting in the first divided area and the second stage blasting in the second divided area mean the first stage blasting and the second stage blasting performed in the blast target area such as the face A. Not limited to cases. The “first stage blasting” in the “first divided area”, the “second stage blasting” in the “second divided area” and their intervals defined in the claims are among a plurality of divided areas. The step blasting order may be applied to the stage blasting in any two divided areas adjacent to each other. That is, at least if the relationship defined in the claims is established between the “first stage blast” performed at the nth and the “second stage blast” performed at the (n + 1) th Good.

(Test example)
A test example will be described with reference to FIG. In the test example shown in FIG. 8, an electron detonator was used and blasting was performed in a split pattern of two as in the example shown in FIG. As an electron detonator, “eDevII” manufactured by Orica Japan was used. The number of initiation holes 10 was 23 in the first divided area A1 and 21 in the second divided area A2. The time difference between detonation seconds was 17 ms. The total drug amount was 16.6 kg. The first stage blast initiation time (ΣΔt ₁ ) in the first divided area A1 is about 0.4 seconds, and the second stage blast initiation time (ΣΔt ₂ ) in the second divided area A2 is also 0.4 seconds. It was about. The interval ΔT (interval) was set to about 3.4 seconds.

As a result, the peak value of the noise level at the first stage blasting was 39.5 dB. This peak value appeared immediately after the initiation time (ΣΔt ₁ ) of the first stage blasting. The peak value of the noise level at the second stage blasting was 41.7 dB. This peak value appeared near the end of the explosion time (ΣΔt ₂ ) of the second stage blasting. In the interval ΔT (interval) between the first stage blasting and the second stage blasting, the reverberation (echo) of the first stage blasting gradually decreases, and at the start of the second stage blasting (first initiation timing) ) Shows that the reverberation is almost eliminated (that is, the background noise level). As a result, even in the second stage blasting, the peak value hardly increased compared to the first stage blasting. It should be noted that the reverberation of the second stage blasting almost disappeared in about 3.4 seconds (about 7.6 seconds from the start of the first stage blasting) after the completion of the second stage blasting (that is, The background noise level).

  A comparative example will be described with reference to FIG. In the comparative example shown in FIG. 9, the electric detonator was used, and the blasting and blasting were performed at once without dividing the face A. A DS detonator was used as the electric detonator. The number of detonation holes 10 was 44. The time difference between detonation seconds was 250 ms. The total drug amount was 18.2 kg. The explosion time for the blasting was about 2 seconds. As a result, the peak value of the noise level at the stage blasting was 48.4 dB. This peak value appeared in the middle of blasting (around half of the time). During the stage blasting, a noise level of 42 dB or more continued, and even after the stage blasting ended, the reverberation (echo) of the stage blasting remained. Thus, the peak value is higher than that obtained when the face A is divided into two, and it has been confirmed that the present invention is superior in terms of noise level. In the comparative example, although reverberation almost disappears (that is, the background noise level), about 5.7 seconds (about 7.7 seconds from the start of the stage blasting blast) after the stage blasting blasting ends. It cost.

  DESCRIPTION OF SYMBOLS 10 ... Explosion hole, 12 ... Explosive, 13 ... Detonator, A ... Face (blast target area), A1 ... 1st divided area, A2 ... 2nd divided area, L ... Divided line, S ... Predetermined point, TNL ... Tunnel.

Claims (5)

A division step of dividing the blasting target area into a plurality of divided areas;
A blasting step of detonating a detonator for each divided area and performing blast blasting,
In the blasting process,
Perform the first stage blast in the first divided area, and perform the second stage blast in the second divided area so that the initiation time does not overlap with the first stage blast following the first stage blast,
A blasting method characterized in that an interval between the last initiation timing in the first stage blasting and the first initiation timing in the second stage blasting is set longer than the duration of the first stage blasting initiation time. . The blasting target area is a face in tunnel excavation,
2. The blasting method according to claim 1, wherein in the dividing step, the face is divided into a plurality of the divided areas adjacent in the left-right direction. In the dividing step, the face is divided into three divided areas, a central area in the center in the left-right direction, and a left area and a right area located on the left and right of the central area,
In the blasting step, the central stage blasting in the central area is performed as the first stage blasting, and either the left stage blasting in the left area or the right stage blasting in the right area following the central stage blasting. The blasting method according to claim 2, wherein either or both are performed as the second stage blasting. The interval between the first stage blasting and the second stage blasting is not more than 20 times the length of the initiation time of the first stage blasting. The blasting method according to item 1. The blasting according to claim 4, wherein the interval between the first stage blasting and the second stage blasting is 10 times or less of the detonation time of the first stage blasting. Construction method.

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