JPH0756439B2 - Blasting blasting method for underground cavern excavation - Google Patents

Description

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

[Conventional technology]

Generally, in underground cavern excavation, drilling, explosive charge,
An excavation method is used in which the processes such as blasting, shearing, and supporting work are repeated. 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. So, first of all, the free surface is formed by core blasting,
Next, the blast is applied to the free surface formed by core removal, 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, the V-cut and the pyramid-cut are those in which the drilling angle is concentrated at one point in the excavation direction and are punched in a wedge shape or a pyramid shape in the advancing direction. There is a drawback that the drilling efficiency is lowered as a result of the limitation and the piercing accuracy having a great influence on the blasting effect.

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. FIG. 4 shows an example of burn cut, in which holes 3, 3, ... Are parallel to the face 2 of the tunnel 1 in the direction of excavation.
, And the charge holes 4, 4, ... Are pierced, and the charge holes 4, 4 ,. It is a method of destroying. 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, in which the large-diameter hole 5 and the charging holes 4, 4, ... It is a method of loading explosives into the holes 4, 4, ... and blasting them in a simultaneous or stepwise manner to destroy towards the large-diameter hole 5 acting as a free surface.
Also known is a Coromant cut that pierces two large holes.

[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.

In addition, as a result of not performing effective centering and blasting, an effective free surface is not formed in the subsequent blasting and blasting,
There was a problem that the effect of the blasting that was subsequently performed became worse.

Furthermore, in the conventional burn-cut or large-diameter coring method, since a plurality of holes or large-diameter holes are bored, it is necessary to increase the drilling time and to maintain the drilling direction with high accuracy, which improves the drilling efficiency. It was a factor that caused the decrease.

The present invention solves the above-mentioned problems, and increases the number of effective free surfaces by core blasting, and by regularly arranging the free surfaces, the number of perforations and the amount of charging in the blasting are reduced. It is an object of the present invention to provide a blasting method for core removal in underground cavern excavation that improves excavation efficiency.

[Means for solving problems]

For that purpose, the core blasting method in the underground cavern excavation of the present invention is a charging hole that is drilled in the center of the core in parallel to the drilling direction, and a plurality of holes that are drilled in parallel with the polygonal shape around the charging hole. It has a charging hole and a plurality of charging holes drilled on both sides of the polygon in one direction. The plurality of charging holes 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 that are perforated in a polygonal shape are first blasted, then the central charging hole is blasted, and then the vertices of an isosceles triangle whose bottom is a free surface formed after the blasting are loaded. It is characterized in that the core hole having a free surface having a sawtooth-shaped cross section is formed by sequentially blasting the chemical holes.

[Action]

In the centering and blasting method in the underground cavern excavation of the present invention, after blasting a plurality of charging holes punched in a polygonal shape,
Form the core with a serrated cross-section free surface by blasting the central charge hole and then sequentially blasting the charge holes at the vertices of an isosceles triangle whose base is the free surface formed after blasting. As a result, the number of free surfaces is large and the free surfaces are regularly arranged, and effective core removal can be performed with a relatively small amount of explosive consumption.

〔Example〕

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

FIG. 1 is a diagram showing one embodiment of a core removing and blasting method in underground cavern excavation of the present invention, FIG. 2 is a diagram showing another embodiment of the present invention, and FIG. 3 is a slit in the embodiment of FIG. It is a figure for demonstrating the formation method. In the figure, A is a centering hole, B is a centering hole, a to q are charging holes, 19 is a slit, 20 is a cutting pipe, 22 is a nozzle, 23 is a direction indicating device, 24 is a disc-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,
Perforate j, k, l, m, n, o, p, q, ....

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

j, k, l, m ... Apex of respective equilateral triangles whose bases are between charging holes b-h, between h-e, between e-i and between i-b.

n, o, p, q ... Trigonal vertices whose bases are the charge holes j-h, h-k, i-l, and i-m.

Thereafter, by this method, charging holes are formed on both sides of the core hole A in the horizontal direction.

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 centering hole A is centered into a regular hexagonal columnar shape, and when the charging holes h and i are blasted toward the obtained free surfaces cd and gf, b and h, h Between-e, e-
Free surfaces are formed between i and between i and b. Next, when the charge holes j, k, l, m are blasted toward the free surfaces bh, he, e-i, and i-b, h-h, h-
Free surfaces are formed between k, between i and l, and between im.
Next, these free surfaces j-h, h-k, i-l and im
The charge holes n, o, p, and q are blasted toward. In the following, 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 by performing blast blasting on the sequentially formed free surfaces. The formed cored portion has sawtooth-shaped cavities with a large number of free surfaces and which are regularly arranged, and the effect of subsequent blasting is 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. Slits 1 on both sides of each charging hole b, c, d, ..., O, p, q ...
, 19, and the charging holes a, b, c,
.., o, p, q, ... The point where the disk-shaped slits 24, 24 ,. 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. The charging holes a, b, c, d,
, O, p, q ... are drilled by a rock drill, and then slit cutting pipe 20 connected to a high pressure water generator (not shown).
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.
Are provided and high-pressure water is jetted from the nozzles 22, 22 while advancing the slit cutting pipe 20, the slits 19, 19, ... Are formed over the entire side surface of the charging hole. At that time, a direction indicating device 23 for adjusting the position of the nozzle is provided in each of the charging holes in order to cut the slits 19, 19, ... along the free surface to be formed by blasting. Then, when the slit cutting pipe 20 advances and reaches the hole bottom of each charging hole, the slit cutting pipe 20 is rotated and the hole bottom of each charging hole is discped by the high pressure water jetted from the nozzles 22, 22. The disk-shaped slits 24, 24 are formed by cutting the disk-shaped slits. 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.

Explaining the action, when each charging hole is blasted, as shown in FIG. 2, the fracture stress distribution becomes a substantially elliptical shape with the slits 19, 19 of the adjacent charging holes as the horizontal axis and is 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,
Various changes are possible. For example, in the above embodiment, the centering holes B, B are formed on both sides of the core hole A in the horizontal direction. May be.

Further, in the above embodiment, the core hole A is formed by punching in a regular hexagonal shape, but it may be a regular polygon such as a regular triangle, and is not limited to a regular polygon, and may be formed in a polygonal shape. ,
The same effect is achieved.

Further, in the above-described embodiment, the charging holes forming the heart assisting holes B and B are drilled at the apexes of an equilateral triangle whose base is between the two charging holes. You may.

Further, in the above embodiment, slits are formed in all the charging holes except the central charging hole a, but it may be formed only in the charging hole formed in a regular hexagonal shape. In addition to the auxiliary holes B, a part of the charging holes of the auxiliary holes B may be formed.

〔The invention's effect〕

As is clear from the above description, according to the present invention, after the charging holes punched in a polygonal shape are blasted, the central charging hole is blasted, and then the free surface formed after blasting is set as the base. Since the charging holes at the vertices of the isosceles triangle are sequentially blasted, effective core removal can be performed with a relatively small amount of explosive consumption.

Further, since the cored portion having the sawtooth-shaped free surface is formed, the number of free surfaces is large and the free surfaces are regularly arranged.
The efficiency of digging can be improved, and the blasting plan such as the number of holes to be blasted, the arrangement of the charging holes, and the amount of charging becomes easy.

Further, it is not necessary to drill a plurality of holes or holes having a large diameter, and it is possible to shorten the drilling time and further improve the excavation efficiency.

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 core removing and blasting method in underground cavern excavation of the present invention, FIG. 2 is a diagram showing another embodiment of the present invention, and FIG. 3 is a slit in the embodiment of FIG. FIGS. 4 and 5 are diagrams for explaining the forming method, and FIGS. 4 and 5 are diagrams for explaining the conventional centering method. A: core removing hole, B: centering hole, aq ... charging hole, 19
…… Slits, 20 …… Cutting pipes, 22 …… Nozzles, 23…
… Direction indicator, 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 (56) References JP-A-57-90600 (JP, A) JP-A-60- 69500 (JP, A) JP-A-57-105700 (JP, A)

Claims (3)

[Claims] 1. A charging hole formed in the center of a cored hole in parallel with the excavation direction, a plurality of charging holes formed in parallel with the charging hole in a polygonal shape, and one direction of the polygonal shape. It has a plurality of charging holes perforated on both sides, and the plurality of charging holes are perforated at the vertices of an isosceles triangle whose base is a free surface formed after blasting, and then the plurality of charging holes are first perforated. Cross-section by blasting the charging holes in the center, and then blasting the charging holes at the vertices of an isosceles triangle whose base is the free surface formed after the blasting. A method for blasting a core in underground cavern excavation, characterized by forming a core-cored portion having a serrated free surface. 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 of the cored portion. The method for blasting a core in the underground cavern excavation according to item 1. 3. A core-breaking blast in underground cavern excavation according to claim 1 or 2, characterized in that a disk-shaped slit is formed at the hole butt of all or part of the charging hole. Method.