JPH11324558A - Blasting method of rock bed or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate cracks inside a scheduled drilling line, improve working efficiency, and reduce overbreak, by drilling inner and outer pairs of parallel holes along the scheduled drilling line at fixed intervals, making the inside hollow holes, and charging explosive in the outside holes. SOLUTION: Along the scheduled drilling line 3 of a scheduled tunnel drilling plane, pairs of parallel holes 4 are drilled extending over the full circumference at fixed intervals. The outside holes of the parallel holes 4 are set to be explosive charging holes 4A, the inside holes are set to be hollow holes 4B, and both are set to be equal size and diameter. The wall space between the explosive charging hole and the hollow hole is set nearly equal to the hole diameter. After forming a free space 7 on the center part of a plane 2 to be blasted previously surrounded with the scheduled drilling line, explosive charged in the explosive charged holes 4A of the parallel holes 4 is exploded, to drill the ground between the scheduled drilling line 3 and the free space 7. At the blasting, the hollow holes 4B inside the explosive charging holes 4A become weak body parts, cracks are concentratedly generated toward the hollow holes 4B, and the crushing directions are led on the hollow holes 4B side. Hereby, the outer circumferential natural ground is hardly damaged, and the natural ground can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blasting method for crushing objects to be crushed, such as bedrock or blast furnace residual iron and concrete, by blasting.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a tunnel by, for example, blasting a bedrock, a plurality of charging holes are formed at predetermined intervals along a tunnel planned excavation line and a center of the tunnel planned excavation line is formed. A core hole is provided in the part, and a plurality of charging holes are also drilled around the core part, and the explosive loaded in the charging hole is charged from the inner charging hole along the planned drilling line It is known to excavate tunnels by blasting them sequentially.

[0003] In such a method for excavating a tunnel by blasting, when the charging hole is a circular hole, the crushing energy due to the blast propagates concentrically and radiatively to the bedrock outside the planned excavation line. Cracking and fracturing occur, resulting in extra excavation and undigging, which not only results in a relatively smooth excavation section along the planned excavation line, but also damages the ground outside the planned excavation line and stabilizes the ground. It will spoil the nature.

In order to solve this problem, conventionally, a slit is formed on a wall surface of a blast hole in a direction of a planned excavation line, and a stress concentration is generated in the slit portion at the time of a blast to determine a crack direction. Has been done. In addition, a long hole-shaped blasting hole and a circular hole are alternately drilled at small intervals along the planned excavation line, and an explosive is charged in the blasting hole to explode the hole. In some cases, a stress concentration is generated toward the center to determine a crack direction.

[0005]

However, according to the former method, a separate step for forming a slit in the blast hole is required, so that the efficiency of tunnel excavation is remarkably reduced and the slit is formed. However, there is a problem in that the construction cost rises because the extra equipment must be used. In addition, according to the latter method, two types of drilling machines must be prepared for excavating holes having different shapes such as a long hole-shaped blasting hole and a circular hole. There is a problem that handling efficiency becomes difficult and work efficiency is reduced. For this reason, a long hole-shaped blasting hole can be formed by performing continuous drilling several times using a single circular hole drilling machine, but the digging operation requires a great deal of labor and labor. Further, since the holes are provided along the planned excavation line with respect to the blast holes, cracks generated from the blast holes toward the holes are largely generated even outside the planned excavation line. There is a problem that the ground around the excavation line is damaged and the stability of the ground is lost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to make a crack direction at the time of a blast greatly increase toward an inside surrounded by a planned excavation line, thereby forming a peripheral area. It is an object of the present invention to provide a method of blasting a bedrock or the like which can stabilize a mountain or the like and reduce excavation and reduce the amount of explosive used.

[0007]

According to a first aspect of the present invention, there is provided a method for blasting a rock or the like according to the first aspect of the present invention. A pair of inner and outer juxtaposed holes are drilled at predetermined intervals with the direction toward the center of the enclosed crushed surface as the inner side, the inner hole of each juxtaposed hole as a hole, and the outer hole as a charging hole. After forming a free space in the center of the crushed surface surrounded by the planned excavation line, the explosives loaded in the above-mentioned charging holes in each juxtaposed hole are blown up, and the space between the planned excavation line and the free space It is characterized by excavating a portion to be crushed.

According to a second aspect of the present invention, there is provided a method of forming a free space in the method of blasting a bedrock or the like according to the first aspect, wherein the free space is surrounded by parallel holes drilled along the planned excavation line. A centering portion is provided on the crushed surface to be crushed, and a plurality of charging holes are formed in the crushing surface between the centering portion and the juxtaposed holes, and an inner charging hole close to the centering portion is provided. The free space is formed by sequentially blasting the explosives loaded in these charging holes toward the outer charging holes close to the juxtaposed holes.

According to a third aspect of the present invention, in the blasting method for rock or the like according to the first or second aspect, the crushing surface formed between the juxtaposed holes and the core portion is pierced. A plurality of charging holes are provided as a group at the left, right, upper and lower portions of the surface to be crushed, and these charging holes are sequentially blasted from the inner group to the outer group. It is characterized by forming a free space.

According to a fourth aspect of the present invention, there is provided another method for forming a free space in the method for blasting a rock or the like according to the first aspect, wherein the parallel holes are formed along the planned excavation line. A centering part is provided on the surface to be crushed surrounded by, and another side-by-side hole consisting of a hole and a charging hole is centered on the surface to be crushed between the centering part and the side-by-side hole. A plurality of holes are drilled toward the part side, and these are charged from the charging holes in the inner juxtaposition holes toward the charging holes in the outer juxtaposition holes adjacent to the juxtaposition holes drilled along the planned excavation line. The free space is formed by sequentially blasting the explosives charged in the charging holes.

According to a fifth aspect of the present invention, in the method for blasting rock or the like according to the first or fourth aspect, the cover between the parallel hole and the center hole formed along the planned excavation line is provided. A plurality of juxtaposed holes formed in the crushing surface, a plurality of groups are provided as a group in the left and right upper and lower portions of the crushed surface, and these juxtaposed holes are separated from the inner group. It is characterized by forming a free space by sequentially blasting toward the outer group.

In the method for blasting rock or the like according to any one of the first to fifth aspects, the invention according to the sixth aspect is the same as the first aspect, except that the shape of the holes and the charging holes constituting all the juxtaposed holes is the same. Big,
It is characterized by being formed in the same shape.

[0013]

[Explanation] After forming a free space on the crushed surface at the center surrounded by the planned excavation line, the explosive charged in the charging holes in the parallel holes drilled at predetermined intervals along the planned excavation line When blasting is performed, the crushing energy due to the blast is intensively released to the hole side, and the crushing direction can be guided and controlled to the hole side, which is one of the juxtaposed holes. Then, all the holes of the juxtaposed holes are in the central portion side of the crushed surface with respect to the charging holes, that is,
Because it is located on the free space side, large cracks due to crushing energy at the time of blasting are intensively generated in the free space side via holes, and at the same time, the gap between the charge hole created by the crack and the free space Crushed lump or crushed pieces (shear) such as bedrock scatter to the free space side due to the blast. On the other hand, the influence of the crushing energy on the ground around the planned excavation line, which is in the direction opposite to the holes with respect to the charging holes, is small, and the ground can be stabilized without damaging the ground around the ground.

As a method of forming the above-mentioned free space inside the planned excavation line, a centering portion is provided at the center of the surface to be crushed, and the centering portion is bored in parallel with the planned excavation line. A plurality of charging holes or juxtaposed holes consisting of holes and charging holes are drilled on the surface to be crushed between the holes, and the charging hole close to the center hole side and close to the planned excavation line side Can be formed by sequentially blasting toward the charging hole to be formed. In this case, the crushing energy due to the blast is always concentrated toward the core by piercing the holes with the holes facing the core in the parallel holes consisting of the holes and the charging holes. As a result, smooth excavation can be performed.

Further, a plurality of charging holes or holes and a charging hole formed in the crushed surface between the parallel hole and the center hole formed along the planned excavation line. A plurality of parallel holes are provided as a group at the left, right, upper and lower portions of the surface to be crushed, and these holes are sequentially arranged from the inner hole group close to the center hole to the outer hole group. By blasting, it is possible to smoothly excavate a free space portion which is expanded in the left, right, up and down directions from the center to the planned excavation line.

By making the shape of the hole and the charging hole the same and the same, the excavation of the parallel hole composed of the hole and the charging hole can be a kind of drilling machine. It can be easily and efficiently used. In addition, the crushed surface surrounded by the planned excavation line is provided along the planned excavation line from the side-by-side hole composed of the charging hole or the hole and the charging hole on the side of the core. By exploding the explosives loaded in all the charging holes sequentially at regular intervals toward the holes, immediately after the formation of the free space section, the charging holes in the parallel holes group along the planned excavation line The crushed surface due to the blasting can be continuously formed.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a method of excavating a horseshoe-shaped tunnel in a rock mass 1 as an object to be crushed by the blasting method of the present invention. At predetermined intervals, the juxtaposed holes 4 composed of a pair of inner and outer circular holes are formed over the entire circumference with the direction toward the center of the crushed surface 2 as the inside. In these juxtaposed holes 4, an outer circular hole drilled so as to be in contact with the planned excavation line 3 is used as a charging hole 4A, and a circular hole drilled inside is used as a hole 4B. The small holes 4A are provided at small intervals in the direction away from the planned excavation line 3. The charging hole 4A and the hole 4B are circular holes of the same size and the same shape, and the distance between the centers thereof is about twice the diameter of the charging hole 4A or the hole 4B. The space between the opposing hole walls of the hole 4A and the hole 4B is formed substantially equal to the diameter of the charging hole 4A or the hole 4B.

Further, a plurality of charging holes 4A are formed in the lower center of the crushed surface 2 surrounded by the planned excavation line 3 at predetermined intervals in the vertical and horizontal directions. Heart 5
Are formed in the first charging hole group a. In addition, a large number of charging holes 4A are provided on the crushed surface 2 between the first charging hole group a and the planned excavation line 3 having the juxtaposed holes 4 at predetermined intervals vertically and horizontally. Has been drilled.

When the core hole 5 is formed by the blasting of the explosive 6 loaded in the first charging hole group a, a predetermined time difference from the blasting of the first charging hole group a occurs. Inner charging hole
By exploding the explosive 6 from 4A toward the outer charging hole 4A, the free space portion 7 is expanded and formed from the core portion 5 toward the planned excavation line 3, and the core portion is formed. A second charging hole group b comprising a plurality of charging holes 4A surrounding the first charging hole group a for forming the first charging hole group 5;
A third charging hole group c provided on both left and right sides of the second charging hole group b so as to sandwich the second charging hole group b; Fourth charging hole groups d, d are provided in a row, and these first to fourth
In the charging holes 4A provided on the crushed surface 2 between the charging hole groups a to d and the juxtaposed holes 4 provided along the upper and lower edges of the planned excavation line 3, first to Hole groups provided in series in the horizontal direction along the top and bottom of the four charging hole groups a to d are referred to as fifth and sixth charging hole groups e and f, respectively, and above the fifth charging hole group e. Seventh to ninth charging hole groups g, h, and i each formed of a group of holes provided in series in the lateral direction at predetermined intervals in the vertical direction on the side.

Also, in the juxtaposed holes 4 provided along the planned excavation line 3, tenth juxtaposed juxtaposed holes provided along the left and right side edges of the planned excavation line 3 are provided. Hole groups j, j are arc-shaped juxtaposed holes provided along the upper edge and horizontal series juxtaposed holes provided along the lower edge, respectively. The groups are k and m.

All the charging holes 4A and the holes 4B have the same diameter and are formed to a predetermined depth in the length direction of the tunnel. These charging holes 4A or holes 4B are covered by using a drilling machine (not shown) in which a long drilling rod provided with a cutting bit at the tip is rotated and arranged in the longitudinal direction. It is formed by piercing from the crushing surface 2 to a desired depth in the tunnel length direction.

As described above, the first drilling machine described above
After the ninth to twelfth charging hole groups a to i and the tenth to twelfth juxtaposing hole groups j to m, the charging holes are moved from the first hole group to the twelfth hole group.
By exploding the explosives 6 loaded in 4A sequentially at predetermined time intervals, a tunnel portion having a predetermined length along the planned excavation line 3 is excavated on the crushed surface 2 of the bedrock 1.

That is, first, the explosive 6 is inserted into all the charging holes 4A of the first to ninth charging hole groups a to i and all the charging holes 4A of the tenth to twelfth juxtaposing hole groups j to m. Is loaded. At this time, from the explosive 6 loaded in the charging hole 4A of the first charging hole group a to the twelfth parallel hole group m
The explosives 6 loaded in the charging holes 4A are sequentially blasted with a constant time difference, for example, a time difference of 0.25 seconds. As such a blasting means, an electric detonator (not shown) having a delay device built-in together with an explosive is used, and an instantaneous electric detonator having no delay device is provided in the charging hole 4A of the first charging hole group a. And the second through the charging holes 4A of the second charging hole group a.
Into the charging holes 4A of the twelve juxtaposed hole groups, an electric detonator including a delay device set to operate at a predetermined time interval is sequentially inserted.

Then, as shown in FIGS. 3 and 4, a blaster 7 is installed at an appropriate place in the already excavated tunnel, and this blaster 7 is connected to all the electric detonators with the lead wires 8 and then the lead wire. By energizing 8, the explosives 6 loaded in the charging holes 4A are exploded from the first charging hole group a to the twelfth juxtaposed hole group m sequentially with a predetermined time difference.

This blasting operation is completed in about several seconds. During this time, the blasting state of the rock is determined by the explosives 6 in all the charging holes 4A of the first charging hole group a to be blasted first. The bedrock surrounded by the first charging hole group a bursts and crushed pieces (shears) are blown off by the blasting force toward the already excavated tunnel side, and the core portion 5 in which some crushed pieces remain. Is formed. The explosives 6 in all the charging holes 4A of the second charging hole group b are exploded with a certain time difference, and the rock portion between the second charging hole group b and the core 5 is crushed. .

At this time, a large number of cracks are formed from the respective charging holes 4A of the first charging hole group a toward the charging holes 4A of the second charging hole group b due to the blast of the first charging hole group a. This crack becomes a weakened portion of the bedrock, and the crushing energy caused by the blast of the explosive 6 loaded in the second charging hole group b causes the space between the core portion 5 and the second charging hole group b. The rock portion is reliably crushed and scattered into the core portion 5 and the tunnel to form the free space portion 7 in which the core portion 5 is enlarged.

Hereinafter, the third charging hole group c to the ninth charging hole group
The charge group i is sequentially blasted with a certain time difference, and the free space portion 7 is further expanded. Also in this case, a crack is generated from the inner charging hole 4A that has been blasted earlier to the outer charging hole 4A, and a continuous crack is generated by the blast of the outer charging hole 4A. As described above, the crushing of the rock portion between these interior and exterior medicine holes by blasting is performed smoothly and reliably.

In the state in which the blasting up to the ninth charge group i has been performed in this way, as shown in FIG. 2, for a moment, the large-diameter free space reaching the vicinity of the planned excavation line 3 is obtained. The portion 7 is formed, and from this state, the tenth to twelfth juxtaposed hole groups j provided along the planned excavation line 3
The explosive 6 in the charging hole 4A at the distance of ~ m is blasted, and a tunnel having an outer peripheral surface along the planned excavation line 3 is formed.

That is, first, the explosives 6 in all the charging holes 4A of the tenth parallel hole group j are blasted, so that the bedrock on both sides surrounded by the planned excavation line 3 is crushed. At this time, when the explosive 6 explodes, a hole 4B is provided inside the charge hole 4A, so that the hole 4B becomes a weak part of the bedrock and a crack is formed by the blast.
And the crushing energy is intensively released toward the holes 4B, and the crushing direction is guided toward the holes 4B. Further, a large number of cracks are generated from the free space portion 7 toward each of the holes 4B due to blasting at the time of forming the free space portion.
Of the explosive 6 in the charge hole 4A of the charge hole 4A
While the crack toward 4B is continuously broken by the crushing energy of the explosive 6, the bedrock portion between the charging hole 4A and the free space portion 7 is crushed through the crack and scatters to the free space portion 7 side, The rock energy outside the planned excavation line 3 has little influence of the crushing energy, and the ground around the planned excavation line 3 is hardly damaged.

Similarly, the explosives 6 in the charging holes 4A in the eleventh juxtaposed hole group k and the twelfth juxtaposed hole group m are successively blown off at a fixed time interval. Part of the rock is crushed and the shear is deposited in the free space 7. By eliminating this shear, a tunnel portion having a fixed length is formed on the crushed surface 2 surrounded by the planned excavation line 3. Then, a plurality of groups of charging holes a to i and a plurality of holes j to m juxtaposed in the same manner as described above are formed in the crushed surface 2 surrounded by the planned excavation line 3 and charged into the charging holes 4A. By exploding the explosives 6 sequentially with a time lag, the tunnel is dug. The distance between the interior and exterior holes was set to be long, and only the continuous crack between the interior and exterior holes was generated without crushing the rock between the interior and exterior holes by the blasting force. The rock part surrounded between the interior and exterior boreholes may be removed by excavation.

FIG. 5 shows another embodiment of the method of blasting rock, which is blasted by a suitable excavation tool in advance at the lower center of the crushed surface 2 surrounded by the planned excavation line 3 or in the same manner as in the above embodiment. The centering portion 5 is formed by
The first to eighth juxtaposed hole groups a ′ to h ′ are provided in the crushed surface 2 between the digging line 3 and the planned excavation line 3 in place of the second to ninth charging hole groups b to i in the above embodiment. It becomes.

That is, at predetermined intervals along the outer peripheral edge of the planned tunnel excavation surface, that is, the planned excavation line 3 of the crushed surface 2,
The same shape and size of the charging hole with the same perforation form as the above embodiment
A plurality of charging holes 4A of the above-described embodiment are formed in the crushing surface 2 surrounded by the centering portion 5 and the side-by-side holes 4 by piercing the side-by-side holes 4 composed of the holes 4A and the holes 4B. A juxtaposed hole 4 composed of a charging hole 4A and a hole 4B is formed in the same portion as the installation position. Charging hole
The space between the opposing hole walls of 4A and the hole 4B is the charging hole 4A or the hole 4B.
, And all the juxtaposed holes 4 have the holes 4B disposed toward the centering portion 5, that is, inward.

Then, a first juxtaposed hole group a 'is formed by a plurality of charging holes surrounding the core hole 5, and the first juxtaposed hole group a' is formed.
A second parallel hole group b 'is provided on both left and right sides of the first parallel hole group a' so as to sandwich the first parallel hole group a ', and a predetermined interval is left and right outside the second parallel hole groups b' and b '. Holes arranged in a row in the vertical direction
c ′ and c ′ are provided, and these first to third
In the juxtaposed holes 4A provided on the crushed surface 2 between the juxtaposed hole groups a 'to c' and the juxtaposed holes 4 provided along the upper and lower edges of the planned excavation line 3, the first Fourth and fifth parallel hole groups d 'and e', respectively, are arranged in series in the horizontal direction along the top and bottom of the third parallel hole groups a 'to c'. Sixth to eighth parallel hole groups f ', g', and h 'are formed on the upper side of the hole group d' and are formed of hole groups provided in series in the horizontal direction at predetermined intervals in the vertical direction. doing.

In the juxtaposed hole 4 provided along the planned excavation line 3, as in the above-described embodiment,
The tandemly arranged hole groups provided along the left and right side edges of the planned excavation line 3 are referred to as ninth parallel hole groups i ′ and i ′, and the arc-shaped parallel hole groups provided along the upper edge. And a horizontal series of parallel hole groups provided along the lower edge and the tenth and eleventh parallel hole groups j ′ and k ′, respectively.
And

As described in the above embodiment, all the charging holes 4A and the holes 4B have the same diameter, and rotate and lengthen a long piercing rod provided with a cutting bit at the tip. It is formed by piercing from the surface to be crushed 2 to a desired depth in the length direction of the tunnel by using a piercing machine (not shown) arranged in the direction.

As described above, the first drilling machine described above is used by the drilling machine.
After drilling the eighth through the parallel hole groups a'-h 'and the ninth through the eleventh parallel hole groups i' through k ', the charging holes 4A of the first hole group to the charging of the twelfth hole group are formed. In the same manner as in the above embodiment, the hole 4A is charged with an electric detonator having a built-in explosive 6 which is to be exploded with a certain delay time, and the explosive 6 is blasted, so that the rock 1 is crushed. A tunnel of a fixed length is excavated on the surface 2.

At this time, in this embodiment, the core space 5 is enlarged by sequentially blasting the explosives 6 loaded in the charging holes 4A of the first to eighth parallel holes a 'to h'. When forming the part 7, if the explosive charged in the charging hole 4A explodes,
A hole 4B provided in the vicinity of the charging hole 4A toward the core opening 5 side becomes a weakened portion of the rock, and a crack is generated by the blast.
The crushing energy is intensively generated toward 4B and the crushing energy is
Rocks are intensively opened to the side, the crushing direction is guided to the hole 4B side, and cracks are continuously formed in the free space portion 7 side. The portion can be crushed through the crack and scattered to the free space portion 7 side, so that the free space portion can be reliably enlarged and formed.

When the blast up to the eighth juxtaposed hole group h 'is performed, as shown in FIG. 6, an instantaneously expanded enlarged free space portion 7 is formed, and the planned excavation is continued from this state. The ninth to eleventh parallel hole groups i ′ provided along the line 3
The explosive 6 in the charging hole 4A at k ′ is sequentially exploded with a certain time difference, and the fracture energy is greatly generated on the side of the hole 4B to crush the bedrock between the free space portions 7 while the plan The effect of the crushing energy is reduced on the outer rock portion of the excavation line 3 to form a smooth tunnel peripheral wall along the planned excavation line 3 without substantially damaging the outer ground.

As shown in FIGS. 7 and 8, the explosive 6 loaded in the charging hole 4A is blasted by installing a blaster 7 in an appropriate place in the already excavated tunnel and incorporating the blaster 7 and the explosive 6 therein. This is performed by connecting the electric detonator with the lead wire 8 and energizing the lead wire 8. In each of the embodiments described above, the method of blasting the bedrock for excavating the tunnel has been described.However, the blasting method of the present invention is also applied to the blasting of crushed materials such as residual iron or concrete in a blast furnace. Is also good.

[0040]

As described above, according to the method for blasting rock or the like of the present invention, the crushed surface of rock or the like is directed along the planned digging line toward the center of the crushed surface surrounded by the planned digging line. A pair of inner and outer juxtaposed holes are drilled at predetermined intervals with the direction inside, the inner hole of each juxtaposed hole is a hole, the outer hole is a charging hole, and the crushed surface surrounded by the planned excavation line After forming a free space in the center of the, the explosives loaded in the charging holes in each side-by-side hole are blown up to excavate the crushed portion between the planned excavation line and the free space, The crushing energy due to the blast is intensively released to the hole side, and the crushing direction can be guided and controlled to the hole side which is one of the parallel holes. Because all the holes in the juxtaposed holes are located inside the charging holes, that is, on the free space side, Large cracks due to the crushing energy at the time of blasting can be intensively generated in the free space side via holes, and at the same time, crushed parts such as bedrock between the charge holes created by the cracks and the free space Can be crushed to the free space side, and the ground can be stabilized without substantially damaging the ground around the planned excavation line.

Further, as described above, since the crushing energy due to the blasting is released to the hole side and most of the crushing energy is controlled to go to the hole side, compared to the case where only the charging hole is used. In the case of the same amount of explosives, the distance between adjacent charging holes can be increased, and when the distance between the charging holes is the same, the amount of explosives can be reduced, making economical and efficient blasting work possible. It is possible.

According to the second or fourth aspect of the present invention, a centering portion is provided on the surface to be crushed, and the centering portion and the centering portion are formed along the planned excavation line. A plurality of charging holes or juxtaposed holes consisting of holes and charging holes are drilled on the surface to be crushed between the holes, and the charging hole close to the center hole side and close to the planned excavation line side Since the blasting is performed sequentially toward the charging hole to be formed, the free space portion in which the center portion is enlarged toward the planned excavation line can be easily excavated and formed. As described above, in the juxtaposed hole composed of the hole and the charging hole, by piercing the hole with the hole facing the center, the crushing energy due to the blast is always directed toward the center. This allows the drilling to be concentrated and smooth.

Further, the invention according to claim 3 or claim 5
According to the invention according to the above, a plurality of charging holes or a plurality of charging holes drilled on the surface to be crushed between the alignment holes and the centering portion, and the alignment holes formed of the charging holes are centered. And a plurality of groups are provided as a group on the left and right upper and lower portions of the surface to be crushed between the juxtaposed holes provided along the planned excavation line, and these holes are provided as inner holes adjacent to the center hole. Since the blasting is performed sequentially from the group toward the outer hole group near the planned drilling line, every time the explosive loaded in the group of holes is blasted, the drilling shear is efficiently crushed to the free space side while the The free space can be sequentially enlarged in the left, right, up and down directions.

According to the sixth aspect of the present invention, the holes forming the juxtaposed holes and the charging holes have the same size and the same shape. Compared with the drilling work that forms a notch, it is possible to easily and efficiently excavate parallel holes consisting of holes and charging holes using a single type of drilling machine, thereby improving workability and reducing construction costs. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a simplified front view of a crushed surface showing one embodiment of a blasting method of the present invention;

FIG. 2 is a simplified front view showing a state in which a free space portion is formed;

FIG. 3 is a simplified vertical sectional side view showing a state in which a lead wire is connected to an explosive in a charge hole;

FIG. 4 is a simplified cross-sectional view thereof,

FIG. 5 is a simplified front view of a crushed surface showing another embodiment of the blasting method of the present invention;

FIG. 6 is a simplified front view showing a state in which a free space portion is formed;

FIG. 7 is a simplified vertical sectional side view showing a state in which a lead wire is connected to an explosive in a charge hole;

FIG. 8 is a simplified cross-sectional view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rock 2 Surface to be crushed 3 Planned excavation line 4 Side-by-side hole 4A Charge hole 4B Void 5 Core hole 6 Explosive 7 Free space

Claims (6)

[Claims] 1. A pair of inner and outer juxtaposed holes are formed at predetermined intervals in a surface to be crushed such as a bedrock along a planned excavation line with a direction toward the center of the crushed surface surrounded by the planned excavation line being inside. After setting the inner hole of each juxtaposition hole as a hole and the outer hole as a charging hole, and forming a free space in the center of the crushed surface surrounded by the planned excavation line, A method of blasting rock or the like, characterized by blasting an explosive charged in the charging hole and excavating a portion to be crushed between a planned excavation line and free space. 2. A pair of inner and outer juxtaposed holes are formed at predetermined intervals in a surface to be crushed such as a bedrock along a planned excavation line with a direction toward the center of the crushed surface surrounded by the planned excavation line being inside. The inner hole of each juxtaposition hole is used as a hole, the outer hole is used as a charging hole, and a centering portion is provided on the surface to be crushed surrounded by these juxtaposition holes. A plurality of charging holes are drilled in the surface to be crushed between the core portion and the inner charging hole adjacent to the core portion. The method for blasting rock or the like according to claim 1, wherein the free space is formed by sequentially blasting the explosives charged in the charging holes. 3. The plurality of charging holes formed in the surface to be crushed between the juxtaposed holes and the centering portion are provided in plural groups at right, left, upper and lower portions of the surface to be crushed. 3. The method for blasting rock or the like according to claim 1, wherein the free space is formed by blasting sequentially from an inner group to an outer group. 4. A pair of inner and outer juxtaposed holes are formed at predetermined intervals in a surface to be crushed such as a bedrock along a planned excavation line with a direction toward the center of the crushed surface surrounded by the planned excavation line being inside. The inner hole of each juxtaposition hole is used as a hole, the outer hole is used as a charging hole, and a centering portion is provided on the surface to be crushed surrounded by these juxtaposition holes. A plurality of holes are formed on the surface to be crushed between the core portion and the crushing surface, the holes being made up of holes and charging holes with the holes facing the core portion, and the charging holes in the inner side holes are formed. To form a free space by sequentially blasting the explosives loaded in these charge holes toward the charge holes in the outer juxtaposition holes adjacent to the juxtaposition holes drilled along the planned excavation line The method for blasting rock or the like according to claim 1, characterized in that: 5. A plurality of juxtaposed holes drilled on the surface to be crushed between the juxtaposed holes drilled along the planned excavation line and the center hole, are provided on the left, right, upper and lower portions of the crushed surface. The blasting of a rock mass or the like according to claim 1 or 4, wherein a plurality of groups are provided as one group, and the plurality of groups are blasted sequentially from an inner group to an outer group to form a free space. Method. 6. The charging hole according to claim 1, wherein all of the holes forming the juxtaposed holes and the charging holes have the same size and the same shape. How to blast rocks.