WO2008114939A1

WO2008114939A1 - Blast construction working method for a tunnel

Info

Publication number: WO2008114939A1
Application number: PCT/KR2008/001023
Authority: WO
Inventors: Young Moon Jung
Original assignee: Young Moon Jung
Priority date: 2007-03-20
Filing date: 2008-02-21
Publication date: 2008-09-25
Also published as: KR20080085523A; KR100866105B1

Abstract

A blast construction working method for excavating a tunnel, which can provide the maximum blasting efficiency and reduce an amount of explosive that is unnecessarily loaded by making an amount of explosive loaded in wider holes differ from an amount of explosive loaded in wider sub-holes is provided. The blast construction working method includes punching horizontal holes, which have predetermined depths, in a predetermined arrangement on a working face of the tunnel, loading a detonator and explosive into each of the holes, stemming inlets of the holes charged with the detonator and explosive using stemming material, and detonating the detonator using a blasting machine to explode the explosive. In the punching of the horizontal holes, cut holes are formed at a center of the tunnel, cut wider holes are formed at an outer side of the cut holes at predetermined intervals, wider holes are formed along at least two lines spaced apart from each other at an outer side of the cut wider holes, wider sub-holes are formed between the lines along which the wider holes are formed, bottom holes are formed in a bottom portion of the tunnel, and design contour holes are formed to correspond to a final section of the tunnel. In the loading of the detonator, an amount of the explosive loaded in each of the wider sub-holes is less than an amount of the explosive loaded in each of the wider holes. In the detonating of the detonator, the holes are sequentially blasted outward in order of from the cut holes to the design contour holes.

Description

BLAST CONSTRUCTION WORKING METHOD FOR A

TUNNEL

Technical Field

[1] The present invention relates to a blast construction working method for excavating a tunnel, and more particularly, to a blast construction working method for excavating a tunnel, which can provide the optimal blasting efficiency and reduce an amount of explosive by differently loading an amount of explosive in wider holes and wider sub- holes. Background Art

[2] Generally, blast construction working methods for excavating tunnels are classified into a total cross-section one time blasting method, a dividing blasting method, and a multi-step blasting method. These blasting methods are performed using the following processes commonly.

[3] The blasting methods include a first process for marking the location and the size of a tunnel section on a rock, a second process for punching cut holes, cut wider holes, wider holes, bottom holes, and design contour holes with predetermined depths and angles, a third process for loading detonators and explosive in the punched holes, a fourth process for triggering the detonator and explosive using a blasting machine, a fifth process for removing blasted rocks, and a sixth process for removing floating stones and reinforcing a base rock.

[4] In the prior art tunnel blasting method, as shown in FIG. 6, locations where cut holes 21, cut wider holes 22, wider holes 23a, 23b, 23c, 23d and 23e, bottom holes 25, and design contour holes 24 will be formed are first marked on the working face of the rock. Next, a plurality of blasting holes are formed at a predetermined location within a total cross-section using an excavator such as a rock drill or a jumbo drill. At this point, the holes are formed on a center of the section that will be blasted with predetermined depths. Next, the detonators and explosive are loaded in the holes at each region and the detonators are triggered by a blasting machine.

[5] In the third process for loading the detonators the explosive among the blasting processes of the tunnel blasting method, as shown in FIG. 7, stemming material is also loaded in the holes to be blasted, together with the detonators and the explosive. Here, the detonators and explosive are loaded in a lower portion out of a center of the holes.

[6] There are two types of explosive: normal explosive and explosive for controlled blasting. The cut holes, cut wider holes, peripheral holes, and bottom holes are charged with the normal explosive. The design contour holes are charged with both the normal explosive and explosive for controlled blasting to prevent the damage of a base rock and the over-break.

[7] The detonators in the cut holes are sequentially loaded from a lower side to an up per side in a bilateral symmetry, and then detonators are sequentially loaded in the cut wider holes, bottom holes, and design contour holes toward an outer portion of the cut portion in each region. The detonators are triggered by the blasting machine to blast the tunnel rock. At this point, the triggering is sequentially performed in order of the cut holes, cut wider holes, peripheral holes, design contour holes, and bottom holes. That is, blasting is realized in a concentric circle shape, thereby obtaining a desired section.

[8] In the prior art blasting method, as shown in FIG. 6, a blasting region 233b of the explosive 231b in the hole 23b may partly overlap the blasting region 233c of the explosive 231c in the adjacent hole 23c. Due to a sequential tunnel blasting property, this overlapping affects on the stemming material 232c or explosive 231c in the following blasting holes. This results in as if the stemming is not sufficiently realized or the explosive is not sufficiently loaded.

[9] When the stemming is not sufficiently realized, the blasting force of the explosive is not concentrated on the rock but partly directed out of the hole to be converted into noise. Furthermore, the rock is not blasted correctly, and thus the quake increases.

[10] In the prior art tunnel blasting method, the explosive for controlled blasting may be misfired by the blasting of a portion under the design contour holes in an inferior rock such as a soft rock, a sandstone, and a dike rock, and the base rock that must not be affected by the blasting may be affected by the blasting. This causes the over-break. Therefore, processes for disposing the blasted stones and unfired explosive and a reinforcing process must be additionally performed. This is time consuming and the cost increases.

[11] As described above, the prior art tunnel blasting method has the problems of low efficiency and high cost. Furthermore, the ground quake and noise physically affect the adjacent buildings. This causes the filing of a civil appeal and thus makes it difficult to proceed with the construction working. Disclosure of Invention Technical Problem

[12] The present invention has been made in an effort to solve the limitations of the prior art. It is an object of the present invention to provide a blast construction working method for excavating a tunnel, which can provide the optimal blasting efficiency and reduce an amount of explosive by differently loading an amount of explosive in wider holes and wider sub-holes. [13] Another object of the present invention is to provide a blast construction working method for excavating a tunnel, which can prevent loss of explosive in adjacent wider holes and deterioration of the blasting performance as the wider holes are sequentially blasted. Technical Solution

[14] In order to achieve the objects, the present invention provides a blast construction working method including: punching horizontal holes, which have predetermined depths, in a predetermined arrangement on a working face of the tunnel; loading a detonator and explosive into each of the punched holes; stemming inlets of the holes charged with the detonator and explosive using stemming material; and triggering the detonator using a blasting machine to explode the explosive. In the punching of the horizontal holes, cut holes are formed at a center of the tunnel, cut wider holes are formed at an outer side of the cut holes at predetermined intervals, wider holes are formed along at least two lines spaced apart from each other at an outer side of the cut wider holes, wider sub-holes are formed between the lines along which the wider holes are formed, bottom holes are formed in a bottom portion of the tunnel, and design contour holes are formed to correspond to a final section of the tunnel. In the loading of the detonator, an amount of the explosive loaded in each of the wider sub-holes is less than an amount of the explosive loaded in each of the wider holes. In the detonating of the detonator, the holes are sequentially blasted outward in order of from the cut holes to the design contour holes.

Advantageous Effects

[15] As described above, the present invention provides a blast construction working method for excavating a tunnel, which can provide the optimal blasting efficiency and reduce an unnecessary amount of explosive by differently loading an amount of explosive in wider holes and wider sub-holes. Therefore, the convention excavation process can be used and thus there is no need to perform the excavation work by a skilled worker. In addition, an amount of the explosive can be reduced and quake and noise can be reduced. The affect on the ambient environment can be reduced, and the construction cost can be reduced.

[16] The present invention also provides a blast construction working method for excavating a tunnel, which can prevent loss of explosive in adjacent wider holes and deterioration of the blasting performance as the wider holes are sequentially blasted. Therefore, the optimal blasting efficiency can be realized while using a relatively small amount of explosive. Brief Description of the Drawings

[17] FIG. 1 is a schematic view of an arrangement of blasting holes for a tunnel according to an embodiment of the present invention.

[18] FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1.

[19] FIG. 3 is a cross-sectional view illustrating an amount of explosive in drilled holes according to an embodiment of the present invention.

[20] FIG. 4 is a graph illustrating vibration and noise generated by a blast construction working method for excavating a tunnel according to the prior art.

[21] FIG. 5 is a graph illustrating vibration and noise generated by a blast construction working method of the present invention.

[22] FIG. 6 is a schematic view of an arrangement of drilled holes for a tunnel according to the prior art.

[23] FIG. 7 is a cross-sectional view taken along line B-B of FIG. 5.

[24] FIG. 8 is a sectional view illustrating an amount of explosive in drilled holes according to the prior art.

[25] * Description of the symbols in main portions of the drawings *

[26] 11 : cut hole 12: cut wider hole

[27] 13a, 13b, 13c: wider hole 14a, 14b: wider sub-hole

[28] 15: design contour hole 16: bottom holes

[29] 131a, 141a: explosive 132b, 142a: stemming material

Best Mode for Carrying Out the Invention

[30] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to accompanying drawings.

[31] FIG. 1 is a schematic view of an arrangement of drilled holes for a tunnel according to an embodiment of the present invention; FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1; and FIG. 3 is a cross-sectional view illustrating an amount of explosive in drilled holes according to an embodiment of the present invention. Referring to FIGS. 1 through 3, a blast construction working method for a tunnel according to an embodiment of the present invention includes a punching process for punching holes with predetermined depths and in a predetermined arrangement through a working face for the tunnel, a loading process for loading a detonator and explosive into each of the holes, a stemming process for stemming inlets of the holes charged with the detonators and explosive, and a detonating process for detonating the detonators using a blasting machine. In the punching process, cut holes 11, cut wider holes 12, wider holes 13a, 13b and 13c, wider sub-holes 14a and 14b, bottom holes 16, and design contour holes 15 are formed. In the loading process, an amount of the explosive loaded in each of the cut wider hole 12 and wider sub-holes 14a and 14b is less than an amount of the explosive loaded in each of the cut holes 11 and wider holes 13a, 13b and 13c. [32] In the punching process, the holes with predetermined depths are formed through the working face of the rock in a predetermined arrangement by using a known excavator or drill. That is, the cut holes 11 are arranged in a central portion of the tunnel. The blasting starts from the cut holes 11. The cut wider holes 12 are arranged at an outer side of the cut holes 11 to enlarge a blasting space generated using the cut holes 11. The wider holes 13a, 13b and 13c are formed along at least two lines spaced apart from each other at an outer side of the cut wider holes 12. The wider sub-holes 14a and 14b are formed between the lines along which the wider holes 13a, 13b and 13c are formed. Design contour holes 15 and the bottom holes 16 are arranged at an outer side of the wider holes 13a, 13b and 13c and the wider sub-holes 14a and 14b, where the bottom holes 16 are arranged on a bottom portion of the tunnel, and the design contour holes 15 are formed along a contour of a final section of the tunnel.

[33] In the loading process, the detonators and explosive are filled in the holes formed in the punching process. As shown in FIGS. 2 and 3, the explosive 131b and 131c is filled in the cut holes 11, the wider holes 13b and 13c, and the bottom holes 16 up to approximately 2/3 of each of the hole depths. Explosive 141a is filled in the cut wider holes 12 and the wider sub-holes 14a up to less than 1/3 of each of the hole depths so that the explosive 141a can be hidden in inner sides of new free surfaces formed by the cut holes 11 and the wider holes 13b and 13c.

[34] At this point, the amount of the explosive loaded in the cut wider holes 12 and wider sub-holes 14a may be properly adjusted so that the explosive cannot be exposed to external sides of the free surfaces that are newly formed by the cut holes 11 and wider holes 13b after an angle of rocks that will be blasted depending on the amount of the explosive loaded in the cut holes 11 and wider holes 13b is calculated in advance in accordance with strength and kinds of the rocks. A remaining rock 143a that is not blasted through the blasting in the wider holes 13b is blasted by the blasting in the wider sub-holes 14a and subsequently more rocks are blasted by the successive blasting in the wider holes 13b.

[35] In addition, normal explosive and explosive for controlled blasting may be sequentially loaded in the design contour holes 15 so as to obtain a precision excavation face, reduce damage of a base rock, and prevent over-break.

[36] The stemming process is performed to stem remaining spaces of the holes in which the explosive is loaded so that the blasting force is concentrated inside the rock during the blasting process and to reduce the blasting noise. That is, typical stemming material is filled in remaining spaces of the cut holes 11, cut wider holes 12, wider holes 13a, 13b and 13c, wider sub-holes 14a and 14b, bottom holes 16, and design contour holes 15.

[37] In the detonating process, the cut holes 11, cut wider holes 12, wider holes 13a, 13b and 13c, wider sub-holes 14a and 14b, bottom holes 16, and design contour holes 15 in which the explosive and stemming material are filled, are sequentially blasted. A well- known detonating method may be used for the detonating process. Particularly, in the detonating process, after the cut holes 11 and cut wider holes 12 are sequentially blasted, the wider holes 13a, 13b and 13c and the wider sub-holes 14a and 14b that are alternately arranged at the outer side of the cut wider holes 12 are sequentially blasted from the center to the outer side of the tunnel.

[38] After the above process, when all of the wider holes 13a, 13b and 13c and the wider sub-holes 14a and 14b are blasted, the design contour holes 15 and the bottom holes 16 are blasted to form a final tunnel section.

[39] The explosive of the cut wider holes 12 is not exposed to the free surfaces formed as the rocks are blasted by the blasting of the cut holes 11, but only the stemming portions are exposed. Therefore, when the cut wider holes 12 are blasted, the explosive in the cut wider holes can be blasted while having the sufficient stemming effect, thereby further enhancing the blasting effect and thus reducing the explosive consumption. In addition, the blasting force is concentrated on the rock, and thus the noise and vibration due to the blasting can be reduced.

[40] FIG. 4 is a graph illustrating vibration and noise generated by a blast construction working method for excavating a tunnel according to the prior art, and FIG. 5 is a graph illustrating vibration and noise generated by a blast construction working method of the present invention. As shown in graphs of FIGS. 4 and 5, when the blast construction is performed using the above-described method, the maximum noise MAX dB is reduced to 60.3dB, while it is 72.6dB in the blast construction working method according to the prior art

[41] Furthermore, a peak vector sum indicating an intensity of impact generated in the tunnel during the blasting according to the present invention is 2.167mm/s while a peak vector sum in the prior art is 4.479mm/s. That is, when the blast construction working method of the present invention is used, the blasting impact is reduced to be a half or less of the blasting impact of the prior art. Therefore, the affection on a variety of buildings and natural environments near the tunnel can be further reduced.

Claims

[1] A blast construction working method for a tunnel, comprising: punching horizontal holes, which have predetermined depths, in a predetermined arrangement on a working face of the tunnel; loading a detonator and explosive into each of the punched holes; stemming inlets of the holes charged with the detonator and explosive using stemming material; and detonating the detonator using a blasting machine to explode the explosive, wherein, in the punching of the horizontal holes, cut holes are formed at a center of the tunnel, cut wider holes are formed at an outer side of the cut holes at predetermined intervals, wider holes are formed along at least two lines spaced apart from each other at an outer side of the cut wider holes, wider sub-holes are formed between the lines along which the wider holes are formed, bottom holes are formed in a bottom portion of the tunnel, and design contour holes are formed to correspond to a final section of the tunnel, in the loading of the detonator, an amount of the explosive loaded in each of the wider sub-holes is less than an amount of the explosive loaded in each of the wider holes, and in the detonating of the detonator, the holes are sequentially blasted outward in order of from the cut holes to the design contour holes.

[2] The blast construction working method of claim 1, wherein the explosive loaded in each of the wider sub-holes is loaded to a depth where the explosive is hidden below a free surface formed through the blasting in the wider holes formed on an inner side of the wider sub-holes, and a stemming portion of each of the wider sub-holes is exposed to the free surface formed through the blasting in the wider holes.

[3] The blast construction working method of claim 1 or 2, wherein the explosive loaded in each of the cut wider holes to a depth where the explosive is hidden below a free surface formed through the blasting in the cut holes formed on an inner side of the cut wider holes, and a stemming portion of each of the cut wider holes is exposed to free surface formed through the blasting in the cut holes.