JPH087038B2 - Blasting method in underground caving - Google Patents

Description

The present invention relates to a blasting method for excavating an underground cavern such as a tunnel or a large-scale underground cavern.

[Conventional technology]

Generally, in underground cavern excavation, an excavation method in which processes such as drilling, charging of explosives, blasting, shearing treatment and construction of supporting works are repeated is adopted. Among them, in order to increase the blasting effect in the blasting plan, the better results are obtained by increasing the number of free surfaces, but in the tunnel, the face face forms the only free surface, which is very restricted. Is in a state. Therefore, a method is adopted in which a free surface is first formed by blasting with core removal, then the free surface formed by core removal is blasted with blasting, and the blasting is performed while sequentially expanding outward.

Conventionally, various methods such as V-cutting, pyramid-cutting, burn-cutting, and large-diameter coring are mentioned as the above-mentioned core-coring method. Of these, V cut and pyramid cut are
Since the piercing angle is concentrated at one point in the digging direction and the piercing is performed in a wedge shape or a pyramid shape in the advancing direction, the advancing length per blast is limited by the excavating cross sectional area, and
As a result of the punching accuracy having a great influence on the blasting effect, there is a drawback that the drilling efficiency decreases.

On the other hand, in the parallel-hole coring method such as the burn-cut or large-diameter coring method, the traveling length per blast can be increased to 3 m or more, so that the excavation efficiency can be greatly improved. Figure 4 shows an example of burn cut.
Holes 3 and 3 parallel to the excavation direction on the face 2 of the tunnel 1.
... and the charging holes 4, 4, ... are perforated to form the charging holes 4, 4, ...
It is a method in which explosives are loaded into the blaster and blasted by simultaneous or stepwise blasting to destroy toward the holes 3, 3, ... Which act as free surfaces. The holes and the charging holes may be arranged in the box cut, clover leaf cut, line cut, or the like.

FIG. 5 shows an example of the large-diameter core removing method,
A large-diameter hole 5 and charging holes 4, 4, ... Are drilled in the facet 2 of the tunnel 1 in parallel with the excavation direction, and the charging holes 4, 4 ,. This is a method in which the large diameter hole 5 that acts as a free surface is destroyed, and a Coromant cut in which two large diameter holes are drilled is also known.

Then, toward the free surface formed by the core removal, the blast is expanded to the surroundings with a time lag to form an underground cavity.

[Problems to be solved by the invention]

The above-described conventional centering method has a problem that the free surface formed after centering has a circular cross section or an irregular cross section. That is, when the free surface has a circular cross section, the fracture stress is dispersed in the tangential direction of the circle in the subsequent blasting of the blast, which causes the problem that the number of holes and the amount of charge must be increased. However, when the free surface has an irregular cross section, it is difficult to arrange the charging holes and design the amount of the charging when expelling and blasting, which causes a problem of overcharging or weak charging.

Further, as a result of the fact that effective core removal and blasting is not performed, an effective free surface is not formed in the subsequent blasting and blasting, and the effect of subsequent blasting becomes worse. It was

Further, in the conventional burn-cut or large-diameter coring method, since a plurality of holes or large-diameter holes are bored,
As the drilling time increases, it is necessary to maintain the drilling direction with high accuracy, which is a factor that reduces the efficiency of drilling.

The present invention is to solve the above-mentioned problems, and by forming an effective free surface by core blasting and by forming a rectangular free surface in subsequent blasting, the number of perforations in paying blasting is increased. It is an object of the present invention to provide a blasting method in underground cavern excavation that reduces the amount of charge and improves the excavation efficiency.

[Means for solving problems]

Therefore, the blasting method in the underground cavern excavation of the present invention comprises a plurality of charging holes b to g formed in a polygonal shape in parallel to the excavation direction and a charging material formed in the center of the polygon in parallel to the excavation direction. Hole a, a plurality of charging holes h to q which are drilled in parallel to the excavation direction on both sides in the horizontal direction of the charging hole formed in the polygonal shape, and a horizontal position apart from all the charging holes by a certain height. A plurality of charging holes 6 which are drilled in parallel with the digging direction
And a plurality of charging holes drilled on both sides in the horizontal direction of the charging hole drilled in a polygonal shape are drilled at the vertices of an isosceles triangle whose base is a free surface formed sequentially after blasting. First, a plurality of charging holes punched in a polygonal shape are generated at once, and then the central charging hole is blasted to form a core-coring hole A having a free surface having a polygonal cross-section. A charging hole B having a sawtooth-shaped free surface is formed by sequentially blasting the charging holes formed at the vertices of an isosceles triangle whose base is the free surface formed after blasting.
It is characterized in that a free surface having a rectangular cross-section is formed by blasting a plurality of charging holes which are perforated in parallel at a certain height apart in a horizontal position. It should be noted that the numbers added to the above-mentioned configurations are for comparison with the drawings in order to facilitate understanding of the present invention, and the configurations of the present invention are not limited thereby.

〔Example〕

 Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 shows a blasting method for excavating an underground cavern according to the present invention.
FIG. 2 is a diagram showing an embodiment, FIG. 2 is a diagram showing another embodiment of the present invention, and FIG. 3 is a diagram for explaining a slit forming method in the embodiment of FIG. In the figure, A is a core hole, B is a centering hole, a to q are charging holes, 6 is a charging hole, 19 is a slit, 20 is a cutting pipe, 22 is a nozzle, 23 is a direction indicator, and 24 is A disk-shaped slit, 25 indicates a crack.

In the embodiment shown in FIG. 1, a charging hole a is bored in the center of the core hole A in parallel with the direction of excavation, and six charging holes are formed in a regular hexagonal shape in parallel with and around the charging hole a. b, c, d, e,
Drill f and g. Further, in the auxiliary holes B, B on both sides of the core hole A in the horizontal direction, the charging holes h, i,
The holes j, k, l, m, n, o, p, q, ... Are drilled parallel to the excavation direction.

h, i ... Apex of respective equilateral triangles having bases between the charging holes cd and the charging holes f-g.

j, k, l, m ... Charge holes b-h, h-e, e-i
Vertices of the equilateral triangles whose bases are the interval and the interval between ib.

n, o, p, q ... Charge holes j-h, h-k, i-l
And the vertices of respective equilateral triangles whose bases are between i and m.

Thereafter, by this method, charging holes are formed on both sides of the core hole A in the horizontal direction. Further, a plurality of charging holes 6, 6, ... Are drilled parallel to the excavation direction in parallel with the horizontal direction at a certain height above the centering hole A and the centering holes B, B.

Next, the blasting method will be described. After loading each charging hole with explosive, first, the charging hole b formed in a regular hexagonal shape,
When c, d, e, f, and g are generated simultaneously, a crack is generated around the central charging hole a, and then the central charging hole a is graduated. As a result, the core hole A is cored into a regular hexagonal column shape,
Next, when the charging holes h and i are stepped toward the obtained free surfaces cd and g-f, b-h, h-e, and e-i.
Free surfaces are formed between the spaces and i-b. Next, when the charging holes j, k, l, m are blasted toward the free surfaces bh, he, e-i and i-b, h-k during j-h, h-k.
A free surface is formed between the spaces i, i, and im. Next, these free planes j-h, h-k, i-l and im
The charge holes n, o, p, and q are blasted toward. Hereinafter, by performing step blasting on the sequentially formed free surfaces, the centering holes B, B having the free surfaces having a serrated cross section are formed on both sides in the horizontal direction of the core hole A. The formed cored portion becomes a sawtooth-shaped cavity with a large number of free surfaces and arranged regularly, and then the blasting holes 6, 6, ... Since the free surface is formed, the effect of subsequent blasting of payment is also increased.

Next, the embodiment of FIG. 2 will be described. Compared with the embodiment of FIG. 1, the arrangement of charging holes and the order of starting are the same, but the only difference is the central charging hole. Charge holes b, c, d, ..., O of core hole A and heart assist holes B, B excluding a,
Circles are formed at points where slits 19, 19, ... Are formed on both sides of p, q, and all or part of the hole ends of the charging holes a, b, c ,. This is the point where the plate slits 24, 24, ... Are formed. The slit 19 is cut along the entire length of each charging hole and along the free surface to be formed by blasting.

A method of forming the slit 19 will be described with reference to FIG. 3. After forming the charging holes a, b, c, d, ..., O, p, q ... With a rock drill, a high pressure water generator (not shown). , A plurality of slit cutting pipes 20 that are connected to each other are sequentially or simultaneously inserted into the charging holes b to q. Nozzles 22, 22 are provided at the tip of the slit cutting pipe 20, and when high pressure water is jetted from the nozzles 22, 22 while advancing the slit cutting pipe 20, the slit 19, over the entire side surface of the charging hole,
19 ... is formed. At that time, slit 19 in each charging hole,
In order to cut 19, along the free surface to be formed by blasting, a direction indicating device 23 for adjusting the position of the nozzle is provided. And the slit cutting pipe 20 advances,
When reaching the hole bottom of each charging hole, the slit cutting pipe 20 is rotated, and the hole bottom of each charging hole is cut into a disk shape by the high-pressure water jetted from the nozzles 22, 22, and the disk-shaped slit 24 ,twenty four
Is formed. The disk-shaped slits 24, 24, ... May be formed in the central charging hole 11 or may be formed in only some of the charging holes.

The method of forming the slit is not limited to the method of forming with the high-pressure water, and a chip for slit cutting may be attached to the rock drill to form the slit.

The operation will be explained. When each charging hole is blasted, as shown in FIG. 2, the blasting stress distribution becomes a substantially elliptical shape with the slits 19, 19 of the adjacent charging holes as the horizontal axis, and the charging holes are adjacent to each other. Cracks 25 are formed between the charging holes through the slits 19 and 19, so that the free surfaces are more regularly arranged than in the embodiment shown in FIG. Further, the disk-shaped slits 24, 24, ... Formed in all or part of the charging hole cause cracks in the direction of being cut off from the ground at the hole butt of each charging hole. Further, the effect of the subsequent payment and blast is further increased.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, in the above-described embodiment, the centering holes B, B are formed on both sides in the horizontal direction of the core hole A, but they may be formed not vertically on both sides but vertically vertically or diagonally both sides. May be.

Further, in the above-mentioned embodiment, the charging holes are arranged in the upper part of the core hole A and the centering holes B, B so as to be parallel to each other in a horizontal direction at a constant height, but in the lower part, the charging holes are fixed. You may arrange | position the charging hole parallel to the excavation direction by arranging in a horizontal direction at a distance from each other.

Further, in the above-described embodiment, the charging holes forming the auxiliary holes B and B are drilled at the apexes of an equilateral triangle whose base is between the two charging holes, but at the storage point of the isosceles triangle. It may be perforated.

Further, in the above embodiment, the core holes A except the center hole a and the charging holes b, c, d, ...
Although slits are formed in all of o, p, q ..., it may be formed only in the charging hole formed in a regular hexagon. You may form in one part.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, after firing a plurality of charging holes punched in a polygonal shape, a free surface having a polygonal cross section is formed by blasting the central charging hole. A core support having a sawtooth-shaped free surface is formed by forming a cored hole having the core and then sequentially blasting the charge holes formed at the vertices of an isosceles triangle whose base is the free surface formed after the blasting. By forming holes, and then by blasting a plurality of charging holes that are perforated side by side at a certain height in a horizontal position, a free surface with a rectangular cross section is formed, so that the free surface is wide and the free surface is regular. It is possible to increase the effect of the blasting and blasting that is arranged and subsequently performed, and it is possible to reduce the number of holes and the amount of charge in the blasting and blasting, and shorten the piercing time and improve the excavation efficiency.

In addition, the blasting plan such as the number of perforations, the arrangement of the charging holes, and the amount of the charging in the blasting for blasting becomes easy.

Furthermore, when a slit and a disk-shaped slit are formed in the charging hole, a crack occurs between these slits in each charging hole, and the core removing effect can be further increased.

[Brief description of drawings]

FIG. 1 is a diagram showing one embodiment of a blasting method in underground cavern excavation of the present invention, and FIG. 2 is a diagram showing another embodiment of the present invention,
FIG. 3 is a diagram for explaining the slit forming method in the embodiment of FIG. 2, and FIGS. 4 and 5 are diagrams for explaining the conventional centering method. A ... Core removing hole, B ... Centering hole, aq ... Charge hole, 6 ... Charge hole, 19 ... Slit, 20 ... Cutting pipe, 22 ... Nozzle, 23 ...
Directional device, 24 ... Disc-shaped slit, 25 ... Crack.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Saburo Ishii 2-16-1 Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (72) Masayoshi Akada 2-16-1 Kyobashi, Chuo-ku, Tokyo Shimizu Construction company (72) Inventor Takashi Wada 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction company

Claims (3)

[Claims] 1. A plurality of charging holes formed in a polygonal shape parallel to the excavation direction, a charging hole formed in the center of the polygonal shape parallel to the excavation direction, and a device formed in the polygonal shape. A plurality of charge holes that are drilled in parallel to the excavation direction on both sides in the horizontal direction of the drug hole, and a plurality of charge holes that are drilled in parallel to the excavation direction in a horizontal position with a certain height apart from all the charge holes. And a plurality of charging holes that are formed on both sides in the horizontal direction of the charging hole that is formed in a polygonal shape, and are formed at the vertices of an isosceles triangle whose base is a free surface that is sequentially formed after blasting. First, after firing multiple charging holes punched in a polygonal shape,
A centering hole having a free surface with a polygonal cross-section is formed by blasting the central charging hole, and then a calibrated hole is formed at the apex of an isosceles triangle whose base is the free surface formed after the blasting. A heart-assisting hole having a serrated free surface in cross section is formed by sequentially blasting the drug holes, and then a plurality of charge holes drilled side by side in a horizontal position at a constant height are blasted to form a rectangular cross section. A blasting method in underground cavern excavation characterized by forming a free surface of a shape. " 2. A slit is formed along a free surface to be formed over the entire length of both side surfaces of all or some of the charging holes except the central charging hole. Blasting method in the underground cavern excavation described. 3. A blasting method for excavation in an underground cavern according to claim 2, characterized in that a disk-shaped slit is formed at the bottom of all or part of the charging hole.