Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42D—BLASTING
  • F42D3/00—Particular applications of blasting techniques
  • F42D3/04—Particular applications of blasting techniques for rock blasting
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42D—BLASTING
  • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
  • F42D1/04—Arrangements for ignition
  • F42D1/06—Relative timing of multiple charges
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42D—BLASTING
  • F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
  • F42D1/08—Tamping methods; Methods for loading boreholes with explosives; Apparatus therefor

Definitions

• the present invention relates to a rock-blasting method for forming dugouts for burying a concrete structure that becomes foundation of steel tower in constructing a power transmission tower which is usually installed on mountain rock. More specifically, the present invention relates to a multistage time delay rock-blasting method for constructing the foundation of a power transmission tower on mountains, wherein a method of applying a formula for calculating the number of bore holes is presented to calculate the number of bore holes fit for the shapes of the dugouts, and charge holes of 38% (tolerance ⁇ 5%) of the total number of bore holes are formed intermittently in the boring part, and if lowering of the blasting effect is expected due to deep-type foundation or the ground layer structure inside the earth surface, blasting is done in sequence and multistage time delay with the detonation pressure directed from inside to outside and from top end to bottom end, so that the blasting effect is further enhanced and also improvement of execution efficiency and easy workability are provided, and the execution cost can be reduced by shortened execution time as well as secured safety.
• the Korea Patent Registration No. 559936 by the applicant of the present invention has disclosed a blasting method, in which the number of bore holes for forming a dugout 4 m by 4 m and 4 m deep is reduced to 65 holes (tolerance ⁇ 5%) by calculating it with the formula for calculating the number of bore holes, and after the necessary digging depths are bored all at once in a diameter of 65 mm (tolerance ⁇ 10%) by hydraulic crawler drill, compound necessary for 38% (tolerance ⁇ 5%) of the number of bore holes is charged in a compound paper diameter of 50 mm (tolerance ⁇ 5%), and they are blasted in sequence from inside to outside by delay action detonator blasting to form dugouts.
• the blasting method using mechanical boring by the number of bore holes calculation formula and delay action detonator is excellent in safety and workability compared with the repetitive boring and blasting work by the conventional manual boring, and reduces construction cost through a shortened construction period and improves the quality of construction, and is an environmentally-friendly method that can reduce noise, spatter of dust and vibration. This method had its viability proved through many times of on-site testing and actual application to construction sites.
• dugout is circular with a diameter of about 3 to 5 m and a depth of about 20 m at most. In terms of depth, it is not out of the scope of work of hydraulic crawler drill so it has no problem with boring work, but there is a problem in the process of substituting the above calculation formula to calculate the number of bore holes. That is, in the above formula for calculating the number of bore holes, the length (m) of one edge of the dugout acts as an important factor in calculating the number of bore holes.
• the shape of some dugouts of deep-type foundation is square, most are circular, so the edge, which is a mathematical graphic element, does not exist. Therefore, there is need a formula for calculating the number of bore holes according to the shape of dugout and a method for applying this or a boring pattern fit for the shape of dugout.
• the area ratio is a numerical expression of the area relation between the circle and the square circumscribing the circle. Even if the diameter of the circle varies, the area remains 78.5% (hereinafter 79% for the sake of convenience) of the square circumscribing the circle, having a relation of constant ratio. Because of this, it is used as a constant for calculating the number of bore holes if the dugout is circular.
• the method disclosed in the Korea Patent Registration No. 559936 by the applicant of the present invention comprises, as shown in Fig. 1, a charging site (3.4 m) and a plugging site (1.1 m) including a remaining site (0.5 m) after boring to a necessary depth (4.5 m including a remaining site) using the crawler drill.
• the number of bore holes is calculated by using the following formula: [26]
• FIG. 1 is a sectional view of the composition of the charging site and plugging site in a conventional blasting method
• FIG. 2 is a schematic plan view showing the blasting sequence using delay action detonator in the conventional blasting method
• FIG. 3 is a sectional view of ground layer with rock, soil and nappe strata mixed in a blasting topography
• FIG. 4 is a sectional view of the composition of the charging site and plugging site in deep-type foundation condition in the conventional blasting method
• FIG. 5 is a schematic plan view showing a charge and no-charge holes for a circular dugout with a diameter of 3 m in a blasting method according to the present invention
• FIG. 6 is a schematic plan view showing a charge and no-charge holes for a circular dugout with a diameter of 4 m in the blasting method according to the present invention
• Fig. 7 is a schematic plan view showing a charge and no-charge holes for a circular dugout with a diameter of 5 m in the blasting method according to the present invention
• FIG. 8 is a sectional view showing charging and plugging layer of the blasting method according to the present invention.
• FIG. 9 is a schematic plan view showing the blasting sequence of the blasting method according to the present invention.
• the present invention uses the formula for calculating the number of bore holes disclosed in the Korea Patent Registration No. 10-559936 registered in 2005 to calculate the number of bore holes in the course of carrying out the blasting work for foundation work for power transmission tower.
• the ratio of charge holes is preferably 38% (tolerance ⁇ 5%) of the total number of bore holes, which is the ratio of charge holes for efficient blasting.
• Patent Registration No. 10-559936 registered in 2005 by the applicant of the present invention is as follows.
• the length (m) of 1 edge of the dugout acts as an important factor in calculating the number of bore holes.
• the number of bore holes is calculated (tolerance ⁇ 5%) for the circular dugout, and the boring pattern is as described below.
• the boring pattern is as described below.
• a delay action rock-blasting refers to blasting in which a delay action detonator having a given second-hour interval is used to make blasting simultaneously from inside to outside laterally and from top to down longitudinally of the earth surface. Its details are as follows.
• the charging and plugging layers can be made of 2 stages or 3 stages or more stages, and if necessary, the length of 1 stage can be elastically adjusted to suit to site conditions so as to enhance the blasting effect.
• Such multistage time delay blasting can be applied to deep-type foundations with a circular or square shape of dugout and also to general foundations with a depth of 4 m in general in which the whole tract of dugout is not formed in rock. Also, by carrying out multistage time delay blasting in a tract where the strata are formed not uniformly due to nappe, etc. so that the strata themselves obstruct the spread of explosion pressure, it can be obtained an excellent blasting effect.
• the specific advantages of multistage time delay blasting are as follows.
• the multistage time delay rock-blasting method for foundation work of power transmission steel tower of the present invention as described above can be applied to deep-type foundations including general foundations and circular dugouts and geological strata of diverse shapes, so that one time blasting is possible, and the blasting effect is enhanced so as to improve the execution efficiency. Also, the multistage time delay blasting provides easy workability, and secures safety and makes it possible to reduce construction cost by shortening the construction period. [78] Although the present invention has been described in connection with the exemplary embodiments illustrated in the drawings, it is only illustrative. It will be understood by those skilled in the art that various modifications and equivalents can be made to the present invention. Therefore, the true technical scope of the present invention should be defined by the appended claims.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Earth Drilling (AREA)
• Life Sciences & Earth Sciences (AREA)
• General Life Sciences & Earth Sciences (AREA)

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Citations (3)

• 2007
  • 2007-03-19 KR KR1020070026438A patent/KR100814356B1/ko not_active IP Right Cessation
  • 2007-04-26 JP JP2009554429A patent/JP2010522289A/ja active Pending
  • 2007-04-26 WO PCT/KR2007/002040 patent/WO2008114899A1/en active Application Filing
  • 2007-04-26 CN CN200780052833A patent/CN101657691A/zh active Pending

Patent Citations (3)

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