JPH087039B2 - 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, first, a free surface is formed by core blasting, then the blast is expanded to the surroundings with a time lag toward the free surface formed by core removal, and finally, in the vicinity of the set cavity forming surface. The remaining rocks are squirted to form an underground cavity.

[Problems to be solved by the invention]

In the above conventional blasting method, in the last blasting in the vicinity of the set cavity forming surface, the entire circumference is blasted at once, and the fracture stress acts on the rock at one time, so the excavated surface is roughened. However, there was a problem that it had a bad effect on the ground, such as causing cracks in the bedrock. Also, since the fracture stress escapes in the tangential direction of the set cavity forming surface, there is a problem that it becomes an arch-like fracture and a large amount of explosive powder is required. It was a problem.

The present invention is to solve the above problems, and an object of the present invention is to provide a blasting method in underground cavern excavation for finishing the excavated surface smooth and preventing adverse effects on the ground such as the occurrence of cracks in the rock mass. To do.

[Means for solving problems]

Therefore, the blasting method in the underground cavern excavation of the present invention comprises a charging hole formed in the centering hole A, a plurality of charging holes formed in the heart assisting holes B on both sides of the centering hole A, and a centering hole. Hole A
In the upper part and the lower part of the assisting hole B, the charging holes 6, which are perforated in multiple stages in a horizontal position at a certain height from the assisting hole B,
7,8,9,10 and a plurality of charging holes and holes 11 drilled along the set cavity forming surface 12, and the charging holes of the core hole A,
The charging hole of the heart assisting hole B, the charging hole 6 formed in the multistage,
Blasting is performed in the order of 7, 8, 9 and 10, and a free surface having a rectangular cross section is sequentially formed in the upper and lower portions of the core hole A and the centering hole B, and a stepped free surface is formed inside the set cavity forming surface. Finally, the plurality of charging holes and holes 11 drilled along the set cavity forming surface are divided into a plurality of blocks C to L,
Blasting is performed with a time difference for each of blocks C to L. 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 for explaining 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 removal hole, B is a centering hole, C to L are blocks, 6 to 10 are charging holes, 11 is a charging hole or a hole, 12 is a setting cavity forming surface, 19
Is a slit, 20 is a cutting pipe, 22 is a nozzle, 23 is a direction indicator, and 25 is a crack.

In the embodiment of FIG. 1, a core hole A and a core hole B formed on both sides of the core hole A are formed with charging holes parallel to the excavation direction, and the core hole A and the core hole are formed. In the upper part and the lower part of B, the charging holes 6, 6, ... And 7, 7, ...
Further, the charging holes 8, 8, are sequentially arranged above the charging holes 6, 6, ...
..., 9, 9, ... and 10, 10, ... are perforated in multiple stages. Further, a large number of charging holes and holes 11, 11, ... Are drilled along the set cavity forming surface 12 of the underground cavern excavation.

Next, the blasting method will be described. After loading each charging hole with explosive, the blasting is performed in the order of the core hole A and the assisting hole B, and the charging hole 6 is formed toward the free surface formed as a result. ,
When blasting 6, ... and 7,7, ..., the rocks are easily destroyed, and a cavity having a free surface with a rectangular cross section is formed. ..., 9, 9, ... and 10, 10, ... are blasted in a stepwise manner to form a stepped free surface inside the set cavity forming surface 12 and finally set cavity forming surface 12 Blast the rocks remaining in. In this blasting, the charging holes or holes 11, 11, ... Formed along the set cavity forming surface 12 are divided into a plurality of blocks C, D,
It is divided into E, F, G, H, I, J, K, and L, and each block is blasted with a time difference.

Next, the embodiment of FIG. 2 will be described. Compared with the embodiment of FIG. 1, the arrangement of the charging holes and the order of starting are the same, except that the setting cavity forming surface 12 is different. Points formed with slits 19, 19, ... on both sides of the charging holes or holes 11, 11, ... formed along with, and the charging holes or holes
Disc-shaped slits 2 at the bottom of all or part of 11, 11, ...
This is the point that formed 4, 24, .... The slit 19 is cut over the entire length of each charging hole and along the setting cavity forming surface 12 to be formed by blasting.

A method of forming the slits 19 and the disk-shaped slits 24 will be described with reference to FIG. 3. After slitting each charge hole with a rock drill, a slit cutting pipe 20 connected to a high-pressure water generator (not shown). Are sequentially or simultaneously inserted into the charging holes or holes 11, 11, .... 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,
A direction indicating device 23 for adjusting the position of the nozzle is provided in order to cut 19, along the set cavity forming surface 12 to be formed by blasting. And slit cutting pipe 20
Moves forward 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 cut into a disk shape by the high pressure water jetted from the nozzles 22 and 22. The plate-shaped slits 24, 24 are formed. The method of forming the slit is
The method of forming with high-pressure water is not limited to the above, and a rock cutting machine may be attached with a chip for slit cutting.

The operation will be described. When the charging holes or the holes 11, 11, ... Formed along the set cavity forming surface 12 are blasted, the fracture stress distribution is as shown in FIG. The slits 19 and 19 are substantially elliptical with the horizontal axis, and cracks 25 occur between the adjacent charging holes through the slits 19 and 19, and can be more easily cut from the bedrock than the embodiment shown in FIG. Will be done. Further, since the disk-shaped slits 24, 24, ... Formed in all or a part of the charging holes cause a crack in the hole butt of each charging hole in the direction of being cut off with the natural ground, the blasting effect is further improved. Increase.

〔The invention's effect〕

As is apparent from the above description, according to the present invention, the free surface having a rectangular cross section is sequentially formed in the upper and lower portions of the core hole and the centering hole, and the step free surface is formed inside the setting cavity forming surface. Finally, a plurality of charging holes and holes drilled along the set cavity forming surface are divided into a plurality of blocks, and blasting is performed with a time difference for each block. The remaining rock is effectively crushed, and the finished surface of the set cavity forming surface becomes smooth, so that adverse effects on the ground such as the occurrence of cracks in the bedrock can be prevented.

Further, when a slit is formed in the charging hole of the setting cavity forming surface, a crack occurs between these slits of each charging hole,
Furthermore, the finished surface becomes smooth, and it is possible to prevent adverse effects on the ground.

[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. A ... Core removing hole, B ... Centering hole, CL ... Block, 6-11
… Charge hole, 12… Set cavity forming surface, 19… Slit, 20… Cutting pipe, 22… Nozzle, 23… Direction indicator, 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 Co., Ltd. (72) Inventor Takafumi Wada 2-16-1, Kyobashi, Chuo-ku, Tokyo Shimizu Construction Co., Ltd. (56) References Industrial Explosives Association's "Blasting Handbook" (Sho 51-9-30) Sankaido, P. 137 ~ 139

Claims (3)

[Claims] 1. A charging hole formed in a core hole, a charging hole formed in each of the core-assisting holes on both sides of the core-coring hole, and a core at the upper and lower portions of the core-coring hole and the heart-supporting hole. The charging hole has a multiplicity of holes bored in a horizontal position at a constant height apart from the auxiliary hole, and a plurality of charging holes and holes bored along the set cavity forming surface, and the core hole is provided. The blasting hole, the priming hole of the heart-assisting hole, and the stuffing hole formed in multiple stages are blasted in order, and a free surface having a rectangular cross section is sequentially formed on the upper and lower portions of the core-piercing hole and the heart-assisting hole. Then, a stepped free surface is formed inside the setting cavity forming surface, and finally, a plurality of charging holes and holes bored along the setting cavity forming surface are divided into a plurality of blocks, and each block is divided into blocks. A blasting method for underground cavern excavation, characterized in that the blasting is performed at different times. " 2. A slit is formed along the set cavity forming surface over the entire length of both side surfaces of a plurality of charging holes or holes bored along the set cavity forming surface. The blasting method in the underground cavern excavation according to item 1. 3. A disk-shaped slit is formed in the hole bottom of all or a part of the plurality of charging holes or holes bored along the setting cavity forming surface. Blasting method in underground cavern excavation according to paragraph 2.