JPH0756440B2 - 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, 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. 5 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. 6 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.

Then, toward the free surface formed by core removal, the blast is expanded to the surroundings with a time lag, and finally the rocks remaining near the set cavity forming surface are blasted to form an underground cavity. Is.

[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.

Further, in the conventional burn-cut or large-diameter coring method, since multiple holes or large-diameter holes are drilled, the drilling time must be increased and the drilling direction must be maintained at a high precision, which improves the efficiency of drilling. It was a factor that caused the decrease.

Furthermore, in the last blasting near the set cavity forming surface, all rocks are blasted at one time, so the fracture stress acts on the rock at one time, the excavated surface is roughened, and the rock is cracked. There is a problem that it adversely affects the natural ground. Further, since the fracture stress escapes in the tangential direction of the set cavity forming surface and causes arch-like fracture, there is a problem that a large amount of gunpowder is required, which is a problem particularly in underground cavern excavation in urban areas.

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 in underground cavern excavation that shortens the excavation time, improves the excavation efficiency, and prevents adverse effects on the ground.

[Means for solving problems]

Therefore, the blasting method in the underground cavern excavation of the present invention,
A charging hole formed in the center of the cored portion in parallel with the excavation direction,
A plurality of charging holes perforated in parallel to the polygonal shape around the charging hole, a plurality of charging holes perforated on both sides in one direction of the polygonal shape, spaced apart from the cored portion and parallel to this. Having a plurality of charging holes that are linearly drilled and a plurality of holes that are drilled along the set cavity forming surface, the plurality of charging holes that are drilled on both sides in one direction of the polygon are Formed at the apex of an isosceles triangle whose base is a free surface that is sequentially formed. First, the charging hole formed in a polygonal shape is blasted, then the central charging hole is blasted, and then the blasting hole is formed after the blasting. The blasting holes at the vertices of an isosceles triangle whose base is the free surface to be formed are sequentially blasted to form a cored portion having a free surface having a sawtooth-shaped cross section, and then a loading hole parallel to the cored portion is sequentially formed. By blasting, a free surface with a rectangular cross section is sequentially formed, and finally the rocks remaining on the set cavity forming surface are removed. Characterized by crushing, further, a charging hole that is drilled in the center of the cored portion parallel to the excavation direction, a plurality of charging holes that are drilled in parallel with the polygonal shape around the charging hole, A plurality of charging holes drilled on both sides in one direction of the polygon, a plurality of charging holes spaced apart from the core core portion and drilled in parallel and linearly therewith, and drilled along the setting cavity forming surface. A plurality of charging holes having a plurality of charging holes, which are drilled on both sides in one direction of the polygon, are drilled at the vertices of an isosceles triangle whose base is a free surface sequentially formed after blasting,
First, the charging holes punched in a polygonal shape are blasted, then the central charging hole is blasted, and then the charging holes at the vertices of an isosceles triangle whose base is the free surface formed after the blasting are sequentially performed. Blasting to form a cored portion having a free surface with a serrated cross section,
Then, by sequentially blasting the charging holes parallel to the cored portion, a free surface having a rectangular cross section is sequentially formed, and finally the rock remaining on the set cavity forming surface is blasted with a time lag for each block. It is a feature.

[Action]

In the blasting method for underground cavern excavation according to the present invention, first, a free surface having a polygonal cross section is formed, then a free surface having a sawtooth cross section is formed, and then a free surface having a rectangular shape is sequentially formed. Finally, the rocks remaining on the set cavity forming surface are crushed or blasted with a time difference for each block.

〔Example〕

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

FIG. 1 is a diagram showing an embodiment of a blasting method in underground cavern excavation of the present invention, FIG. 2 is a diagram for explaining a core removing method in the embodiment of FIG. 1, and FIG. FIG. 4 is a diagram for explaining the slit forming method in the embodiment of FIG. In the figure, A is a centering hole, B is a centering hole, C to L are blocks, a to q are charging holes, 6 to 11 are charging holes, 12 is a setting cavity forming surface, 19 is a slit, 20 is Cutting pipe, 22 nozzle, 23 direction indicator,
Reference numeral 24 indicates a disk-shaped slit, and 25 indicates a crack.

In the embodiment of FIG. 1, a charging hole is bored in the coreing hole A and the centering hole B by a method described later in parallel with the excavation direction, and the charging holes are formed in the upper and lower parts of the centering hole A and the centering hole B. , And 7, 7, ... are bored in parallel with the above, and further, in parallel with this, the loading holes 8, 8, ..., 9, 9 are sequentially provided above the loading holes 6, 6 ,. , ... and 10, 10, ... Further, a large number of charging holes or holes 11, 11, ... Are drilled along the setting cavity forming surface 12 of the tunnel. In the case of blasting only with holes, it is necessary to increase the number of holes and make holes with higher density.

As shown in FIG. 2, the coring portion is formed by forming a charging hole a at the center of the coring hole A in parallel with the direction of excavation, and six charging holes b in a regular hexagonal shape around it. , C, d, e, f, g
Are drilled in parallel. 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 ... Apex of respective equilateral triangles having bases at 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 fired simultaneously, a crack is generated around the central charging hole a, and then the central charging hole a is fired. As a result, the centering hole A is centered into a regular hexagonal column shape, and then, when the charging holes h and i are stepped toward the obtained free surfaces cd and g-f, a gap between b and h is generated. , Between h and e, e
Free surfaces are formed between -i and i-b. Next, when the charging holes j, k, l, m are blasted toward these free surfaces bh, he, e-i, and i-b, h between j and h, h
Free surfaces are formed between -k, i-l, and i-m. Next, the charge holes n, o, p and q are blasted toward these free surfaces jh, hk, i-1 and im. Thereafter, by performing burst blasting on the sequentially formed free surfaces, the centering holes B, B having the free surfaces having the sawtooth cross section are formed on both sides in the horizontal direction of the core hole A.

Then, the formed core portion becomes a cavity having a large number of free surfaces and regularly arranged, and has a sawtooth cross section.
Charge holes 6, 6, ... And 7, 7, ... Towards this free surface
, The rock is easily broken, and a cavity having a free surface having a rectangular cross section is formed. Thereafter, the charging holes 8, 8, ..., 9 are formed toward the sequentially formed rectangular free surface. , 9,
... and 10, 10, ... are blasted by steps, and finally the rock around the set cavity forming surface 12 is crushed.

In this case, when the holes drilled along the set cavity forming surface 12 are holes, cracks are generated between a large number of holes 11, 11, ... At high density, and the holes are easily separated from the bedrock.

On the other hand, when the holes drilled along the set cavity forming surface 12 are used as the charging holes, the charging holes 11, 11, ...
It is divided into D, E, F, G, H, I, J, K and L, and each block is blasted with a time difference.

Next, the embodiment of FIG. 3 will be described. Compared with the embodiment of FIG. 1, the arrangement of charging holes and the order of starting are the same, except that the core holes A and Of the charging holes of the heart assisting holes B, B, the charging holes b, c, d, excluding the central charging hole a,
, O, p, q, or a point in which slits 19, 19, ... Are formed on both sides of the charging holes or holes 11, 11, ... Formed along the set cavity forming surface 12. Charge holes a, b,
The point is that disk-shaped slits 24, 24, ... Are formed at the hole ends of all or part of c, d ,. The slit 19 is cut along the entire length of each charging hole and along the free surface to be formed by blasting.

The method of forming the slit 19 will be described with reference to FIG.
After piercing all the charging holes with a rock drill, a plurality of slit cutting pipes 20 connected to a high-pressure water generator (not shown) are inserted into each charging hole sequentially or simultaneously. Nozzles 22 and 22 are provided at the tip of the slit cutting pipe 20. While advancing the slit cutting pipe 20, high pressure water is supplied to the nozzle 2.
When sprayed from Nos. 2 and 22, 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.

Further, 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 disc-shaped 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 slit 24 may be formed in all the charging holes including the central charging hole a, or may be formed in a part 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 its action, when the charging hole in the cored portion is blasted, as shown in FIG. 3, the fracture stress distribution shows a substantially elliptical shape with the slits 19, 19 of the adjacent charging holes or holes as the horizontal axis. As a result, cracks 25 are formed between the adjacent charging holes through the slits 19 and 19, and the free surfaces are more regularly arranged than in the embodiment shown in FIG. Further, disk-shaped slits 24, 24 formed in all or part of the charging hole,
As a result, a crack occurs in the hole edge of each charge hole in the direction of being cut off from the ground, so the core removal effect is further increased,
The effect of subsequent payment and blasting will be further increased. Further, also in the charging holes or holes 11, 11, ... Formed along the set cavity forming surface 12, cracks 25 occur between the adjacent charging holes or holes via the slits 19, 19, and the rock mass is formed. Will be easily separated from.

The present invention is not limited to the above embodiment,
Various changes are possible. For example, in the above embodiment, the charging hole is formed in a regular hexagonal shape, but a polygonal shape such as a triangle can also achieve the same effect.

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

〔The invention's effect〕

As is apparent from the above description, according to the present invention, first, a free surface having a polygonal cross section is formed, then a free surface having a sawtooth cross section is formed, and then a rectangular free surface is sequentially formed. As the blasting is performed, the rocks remaining on the set cavity forming surface are crushed or blasted with a time lag for each block, which reduces the number of holes and the amount of charge in blasting and shortens the piercing time. The digging efficiency can be improved. 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.

Further, the rock remaining on the set cavity forming surface is effectively crushed, and the finished surface of the set cavity forming surface becomes smooth, so that it is possible to prevent adverse effects on the ground such as occurrence of cracks in the bedrock.

In addition, it is not necessary to form a plurality of holes or large-diameter holes for core removal, and thus the excavation efficiency can be further improved.

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

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a blasting method in underground cavern excavation of the present invention, FIG. 2 is a diagram for explaining a core removing method in the embodiment of FIG. 1, and FIG. FIG. 4 is a diagram for explaining the slit forming method in the embodiment of FIG. 3, and FIGS. 5 and 6 are diagrams for explaining the conventional centering method. A: core removing hole, B: centering hole, C to L: block,
aq ... Charge hole, 6-11 Charge hole, 12 ... Setting cavity forming surface, 19 ... Slit, 20 ... Cutting pipe, 22 ... Nozzle, 23 ... Direction indicator, 24 ...... Disc-shaped slit, 25
……crack.

 ─────────────────────────────────────────────────── ─── Continuation of the 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 (6)

[Claims] 1. A charging hole formed in the center of a cored portion in parallel with the direction of excavation, a plurality of charging holes formed in parallel with a polygonal shape around the charging hole, and one direction of the polygonal shape. A plurality of charging holes drilled on both sides, a plurality of charging holes spaced apart from the cored portion and drilled in parallel and linearly therewith, and a plurality of holes drilled along the set cavity forming surface. Having, one of said polygons
A plurality of charging holes that are drilled on both sides in the direction are drilled at the vertices of an isosceles triangle whose base is the free surface that is sequentially formed after blasting, and then the charging holes that are drilled in a polygonal shape
The center charging hole is blasted, and then the charging holes at the vertices of an isosceles triangle whose base is the free surface formed after the blasting are sequentially blasted to form a cored portion having a free surface having a sawtooth cross section. Then, by sequentially blasting the charging holes parallel to the cored portion, a free surface having a rectangular cross section is sequentially formed, and finally the rock remaining on the set cavity forming surface is crushed. Blasting method in excavation. 2. A slit is formed along the free surface to be formed over the entire length of both sides of all or some of the charging holes or holes except the charging hole at the center of the cored portion. A blasting method for excavating an underground cavern according to claim 1. 3. A blasting method for excavation in an underground cavern according to claim 2, wherein a disk-shaped slit is formed at the bottom of all or some of the charging holes or holes. 4. A charging hole formed in the center of a cored portion in parallel with the excavation direction, a plurality of charging holes formed in parallel with a polygonal shape around the charging hole, and one direction of the polygonal shape. A plurality of charging holes drilled on both sides, a plurality of charging holes spaced apart from the cored portion and drilled in parallel and in a straight line, and a plurality of charging holes drilled along the set cavity forming surface. And a plurality of charging holes perforated on both sides in one direction of the polygon are perforated at the vertices of an isosceles triangle whose base is a free surface formed after blasting, and are first perforated into a polygonal shape. After bursting the charging holes, the central charging hole is blasted, and then the charging holes at the vertices of an isosceles triangle whose base is the free surface formed after the blasting are sequentially blasted to have a sawtooth cross section. Cut by forming a cored part with a free surface and then sequentially blasting the charging holes parallel to the cored part. Sequentially forming a rectangular free surface, blasting method in underground cavities excavation, characterized in that the end with a time difference for each block the remaining rocks set cavity forming surface for blasting. 5. A slit is formed along the free surface to be formed over the entire length of both side surfaces of all or part of the charging hole except for the central charging hole of the cored portion. Blasting method in underground cavern excavation according to the range 4th term. 6. A disk-shaped slit is formed in the hole butt of all or part of the charging hole.
Blasting method for underground cavern excavation described in paragraph.