JP2007322096A - Smooth blasting construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently carry out loading of an explosive without relying on manual work. <P>SOLUTION: In the smooth blasting construction method, charge holes 2a are bored in an outermost circumference of a working face 1, charge holes 2b are bored in an inner side than the outermost circumference, and granular explosives 3 are densely filled in each of the bored charge holes 2a, 2b by mechanical filling. A charge length of the granular explosive 3 to be filled in the charge holes 2b is about 1/2 of a bore length, but a charge length of the granular explosive 3 to be filled in the outermost circumference charge holes 2a is determined by the following procedures. The charge hole 2a is a charge hole for carrying out smooth blasting using a volume decoupling method, and volume of the granular explosive 3 is determined such that air in a gap 6 is attenuated by a shock wave at detonation, and only a gas pressure evenly acts on an inner face of the charge hole 2a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a smooth blasting blasting method mainly applied to a tunnel.

  In tunnel excavation, controlled blasting that controls detonation destruction is widely adopted, and among these controlled blasting, smooth blasting drills a charge hole at the outermost periphery of the face at narrow intervals. By charging such a charge hole with an elongated explosive (hereinafter referred to as SB explosive) smaller than the diameter of the hole, damage to the natural ground due to blasting can be suppressed and less excavation can be reduced.

  When performing control blasting with smooth blasting, as described above, SB explosive is charged in the charge hole drilled in the outermost periphery of the face. However, since the SB explosive is long and soft, such charge operation is performed. It is manually loaded into the drilling hole using a medicinal pipe.

JP 2005-30710 A

  For this reason, it takes time for the charge work and not only the workability is inferior, but also there is room for improvement in terms of safety. In addition, the other charge holes except the outermost periphery are charged with a water-containing explosive containing a cigarette. However, since the two kinds of the water-containing explosive and the SB explosive must be used separately, the problem that the charge work becomes complicated. Also occurred.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a smooth blasting blasting method capable of efficiently loading an explosive without using manual work.

  In order to achieve the above object, the smooth blasting blasting method according to the present invention, as described in claim 1, densely fills the charge hole drilled in the face with a granular explosive by mechanical filling and the outermost periphery. A blocking plug is attached only to the base of the charging hole, and a controlled blast using the volume decoupling method is performed by securing a gap between the blocking plug and the granular explosive.

  Further, in the smooth blasting blasting method according to the present invention, the volume of the granular explosive charged in the outermost charging hole is the gas pressure Ps in the outermost charging hole. The following formula,

          σc> Ps> σt

            σc: Rock compressive strength

            σt: Tensile strength of rock

It adjusts to satisfy.

  In the smooth blasting blasting method according to the present invention, the closing plug is formed into a cylinder, a cone, or a truncated cone using an elastic material, and an outer diameter thereof is larger than an inner diameter of the outermost charged hole. It is formed as follows.

  Further, the smooth blasting blasting method according to the present invention is provided with a through hole through which the conduit is passed along the material axis in the vicinity of the cross-sectional center of the plug, and the cross-sectional shape of the plug is a C-shaped cross section. A slit extending in the radial direction from the through hole is formed.

  Further, in the smooth blasting blasting method according to the present invention, the closing plug is composed of a plurality of closing pieces each having a semicircular shape or a fan-shaped cross section, and the closing pieces are combined in a cylindrical shape, a cone shape or a truncated cone shape. In this case, each of the closed pieces is formed so that a through-hole through which the fire guide pipe is passed is formed in the center of the cross section.

  Smooth blasting, as described in the prior art, controls the direction of the explosive energy during blasting by charging the charge hole drilled on the outermost periphery of the excavated face, and prevents damage to natural ground. SB explosives have been used for such smooth blasting in order to control and finish the excavated surface smoothly.

  Under such circumstances, in view of the problem caused by the fact that the SB explosive having an outer diameter sufficiently smaller than the hole diameter has to be loaded so as to have a long mounting length, the applicant is not using such a hole diameter decoupling method. He focused on whether the volume decoupling method could be adopted.

  However, in the volume decoupling method, a spacer is provided between the plug and the explosive filled in the base of the charge hole (hole) so that a predetermined volume of the gap is maintained between the loaded explosive and the base. Therefore, it is indispensable to solve the problems using conventional SB explosives.

  Therefore, as a result of further research and development, the applicant was able to maintain a gap between the explosive and the hole base without using a spacer if it is a granular explosive that can be closely packed by mechanical filling. It came to obtain a new knowledge.

  That is, in the present invention, a granular explosive is densely filled by mechanical filling into the charging hole cut in the face, and a blocking plug is attached only to the base of the charging hole located on the outermost periphery. A controlled blast using a volume decoupling method is performed with a space between the granular explosives.

  In such a configuration, during detonation, the shock wave is attenuated by the air in the air gap, and only the gas pressure acts uniformly on the charge hole, so that it is possible to suppress the energy at the time of blasting. Since the explosive charged in the outermost peripheral charge hole is a granular explosive, it is possible to fill the machine and eliminate the need for the operator to directly load the explosive. Therefore, safety is improved and workability during charging is dramatically improved. In addition, the explosive to be charged in the outermost periphery and the innermost charge hole is the same type, so the charge work is simplified and coupled with the above-mentioned improvement in workability during charge by machine filling, explosive loading The work efficiency is greatly improved.

  The decoupling index D ′ in the volume decoupling method is conventionally defined by the ratio V′h / V′c between the perforation volume V′h excluding inclusions and the explosive volume V′c, and D ′ = Although the values of 4 to 6 are standard, this known value is based on the premise that a water-containing explosive containing a cigarette that requires a spacer is used, and the explosive diameter is 2/3 to 3 of the charge hole diameter. This value is not necessarily applied in the present invention in which the granular explosive is closely packed in the charge hole by mechanical filling.

  Therefore, the amount of charge is actually changed while paying attention to two points: whether excessive excavation will occur, in other words, whether additional excavation will occur, and conversely whether necessary excavation has been completed. However, by blasting, it will be understood how much charge is appropriate.

  Here, among the above-mentioned charge holes, the volume of the granular explosive charged in the outermost charge hole is expressed by the following equation, where the gas pressure Ps in the outermost charge hole is:

          σc> Ps> σt

            σc: Rock compressive strength

            σt: Tensile strength of rock

As long as there is no unexpected crack in the bedrock and it is uniform, it is possible to roughly grasp the appropriate amount of granular explosive charged in the outermost charging hole, as a result. The volume decoupling index D according to the present invention, that is, the ratio between the volume Vh in the outermost charged hole and the volume Vc of the explosive can be obtained.

  The granular explosive used in the present invention may be, for example, a granular emulsion explosive manufactured by Nippon Kayaku Co., Ltd. and sold by Kayatech Co., Ltd. under the trade name “Landex”. it can. Such a granular explosive is obtained by granulating a hydrous explosive, and is used in a form in which a booster (parent die) that starts up with a detonator with a conducting tube is inserted into the bottom of the hole and subsequently machine-filled.

  Here, as long as the closure plug can secure the volume of the gap as designed, any material can be used, and it can be used in the hole diameter decoupling method or the conventional volume decoupling method. It does not matter if it is clay.

  However, in the hole diameter decoupling method, there is an additional die behind, and in the conventional volume decoupling method, there is a spacer behind, so by taking the reaction force from them, clay can be firmly packed in the hole base. In the present invention, there is a case where the back side is an air gap and no reaction force can be taken, and the hole cannot be firmly closed with clay. In addition, there is also a concern that clay may be pushed in excessively due to the fact that no reaction force can be taken behind, resulting in a decrease in void volume accuracy.

  In such a case, for example, the closure plug is formed in a cylindrical shape, a cone shape or a truncated cone shape using an elastic material, and its outer diameter is formed to be larger than the inner diameter of the outermost charged hole. A method is conceivable.

  More specifically, a through hole is provided in the vicinity of the center of the cross-section of the plug so that the fire guide pipe passes along the material axis, and the cross-sectional shape of the plug is a C-shaped cross section. A slit extending in the radial direction is formed, or the closing plug is constituted by a plurality of closing pieces each having a semicircular or fan-shaped cross section, and the closing pieces are combined into a cylinder, a cone, or a truncated cone. In some cases, it is desirable to form each of the closed pieces so that a through-hole through which the fire guide pipe passes is formed in the center of the cross section.

  In such a configuration, smooth blasting by the volume decoupling method using granular explosives can be efficiently performed by pushing the plug into the charge hole with the lead pipe being passed through the through hole of the plug. Is possible.

  Hereinafter, embodiments of a smooth blasting blasting method according to the present invention will be described with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.

  FIG. 1 is a flowchart showing a procedure of the smooth blasting blasting method according to the present embodiment. As can be seen in the figure, in the smooth blasting blasting method according to this embodiment, as shown in FIG. 2 (a), first, the charge is applied to the outermost periphery of the face 1 (the portion marked 8 in the blasting pattern). The holes 2a are drilled, and the charge holes 2b are drilled inside the outermost periphery (locations indicated as 1, 2,... 7 in the blasting pattern) (step 101).

  Since the outermost charging hole 2a is a charging hole for performing smooth blasting, the drilling pitch is set to be relatively narrow, for example, 45 cm.

  Next, as shown in FIGS. 2B and 2C, the charged explosive holes 2a and 2b are filled with the granular explosive 3 densely by mechanical filling (step 102).

  As the granular explosive 3, for example, a granular emulsion explosive manufactured by Nippon Kayaku Co., Ltd. and marketed by Kayatech Co., Ltd. under the trade name “Landex, both registered trademarks” can be used.

  The machine filling can be performed using a dedicated loading machine equipped with a compressor, and the granular explosive 3 can be compressed and loaded into the charge holes 2a and 2b by air, so that it can be loaded in comparison with human loading. The drug time can be greatly shortened.

  In addition, before charging the granular explosive 3, a detonator with a lead tube (not shown) and a parent die 4 (cigarette-containing explosive) to be detonated with the detonator are inserted in advance into the hole bottom.

  Here, the charge length of the granular explosive 3 filled in the charge hole 2b is about ½ of the drilling length as can be seen in FIG. 2 (b), but the charge hole 2a on the outermost periphery is filled. The charge length of the granular explosive 3 to be determined is determined by the following procedure.

  That is, the charge hole 2a is a charge hole that performs smooth blasting using the volume decoupling method. During detonation, the shock wave is attenuated by the air in the gap 6, and only the gas pressure is charged to the charge hole 2a. The volume of the granular explosive 3 is determined so as to act uniformly on the inner surface of the particle.

  Specifically, the gas pressure Ps in the outermost charged hole 2a is expressed by the following equation:

          σc> Ps> σt

            σc: Rock compressive strength

            σt: Tensile strength of rock

Air is provided in the charge hole 2a so as to satisfy, in other words, the ratio between the amount (volume) of the granular explosive 3 and the volume of the gap 6 is determined. Incidentally, it is possible to obtain the volume decoupling index D, that is, the ratio between the volume Vh in the outermost charged hole 2a and the volume Vc of the granular explosive 3 from this ratio, and the data accumulation is performed while performing actual blasting. By performing the above, the volume decoupling index D for the rock in the construction section can be roughly evaluated.

  Next, the blocking plug 5 is attached only to the base of the outermost peripheral charging hole 2a (step 103).

The closing plug 5 is formed of an elastic material such as rubber or soft plastic, and as shown in FIG. 3, it has a cylindrical shape having an outer diameter d larger than the inner diameter d _{0 of the} charging hole 2a. Yes, the rigidity and outer diameter d of the elastic material are appropriately set so as to withstand the gas pressure at the time of detonation while being pushed into the base of the charge hole 2a.

  Here, the obturator plug 5 is provided with a through-hole 12 through which the igniter tube 11 passes along the material axis in the vicinity of the center of the cross section, and the radial direction from the through-hole 11 so that the cross-sectional shape becomes a C-shaped cross section. A slit 13 extending in the direction is formed.

  With this configuration, it is possible to ensure the airtightness of the gap 6 without applying an excessive force to the heat guide tube 11, and smooth blasting can be performed by the volume decoupling method.

  As explained above, according to the smooth blasting blasting method according to the present embodiment, the charge holes 2a and 2b drilled in the face 1 are densely filled with the granular explosive 3 by mechanical filling, and the outermost periphery is filled. Since the plug 5 is attached only to the base of the charge hole 2a located, and the gap 6 is secured between the plug and the granular explosive 3 so that the controlled blasting using the volume decoupling method is performed. At the time of detonation, the shock wave is attenuated by the air in the gap 6 and only the gas pressure can be made to act uniformly in the charge hole 2a. Since the explosive charged in the charge hole 2a is the granular explosive 3, it is possible to fill the machine, and it is not necessary for the operator to load it manually.

  Therefore, safety is improved and workability during charging is dramatically improved. In addition, since the explosive charged in the outermost charging hole 2a and the inner charging hole 2b are of the same type, the charging operation is simplified, and the above-described workability during charging by machine filling is simplified. Combined with the improvement, work efficiency of explosive loading is greatly improved.

  In the present embodiment, the closure plug 5 is provided with a through hole 12 through which the igniter tube 11 passes along the material axis in the vicinity of the center of the cross section, and from the through hole 11 so that the cross sectional shape becomes a C-shaped cross section. Although the slit 13 extending in the radial direction is formed, the obturator plug 20 shown in FIG. 4 may be used instead.

  The obstruction plug 20 is composed of two obstruction pieces 21a and 21b each having a semicircular cross-sectional shape, and when the obstruction pieces are combined in a cylindrical shape, a penetrating pipe 11 is passed through the center of the cross section. Grooves 22a and 22b are formed in the respective closing pieces 21a and 21b so that holes are formed, and even in such a configuration, substantially the same operational effects as those of the closing plug 5 described above can be obtained.

The flowchart which showed the implementation procedure of the smooth blasting blasting method which concerns on this embodiment. It is the figure which showed the charge holes 2a and 2b drilled by the face 1, (a) is a layout figure (blasting pattern) of a charge hole, (b) is sectional drawing of the charge hole 2a, (c) Is a sectional view of a charge hole 2b. It is the figure of the obstruction | occlusion stopper 5, (a) is a perspective view, (b) is a side view. The perspective view of the obstruction | occlusion stopper 20 which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Face 2a, 2b Charge hole 3 Granular explosive 5,20 Blocking plug 6 Cavity 12 Through-hole 13 Slit

Claims (5)

The charging hole drilled in the face is filled with granular explosive densely by mechanical filling, and a blocking plug is attached only to the base of the outermost charging hole, and a gap is formed between the blocking plug and the granular explosive. A smooth blasting blasting method characterized by performing controlled blasting using the volume decoupling method. Of the charge holes, the volume of the granular explosive charged in the outermost charge hole, the gas pressure Ps in the outermost charge hole is represented by the following formula:
σc>Ps> σt
σc: Rock compressive strength
The smooth blasting blasting method according to claim 1, wherein σt is adjusted to satisfy the tensile strength of the rock. The said obstruction | occlusion stopper is formed in the shape of a cylinder, a cone, or a truncated cone using an elastic material, The outer diameter is formed so that it may become larger than the inner diameter of the said outermost periphery charging hole. Smooth blasting blasting method. A through hole is provided near the center of the cross-section of the obstruction plug along the material axis, and a slit extending in the radial direction from the through hole so that the cross-section of the obstruction plug has a C-shaped cross section. The smooth blasting blasting method according to claim 3 formed. The closing plug is composed of a plurality of closing pieces each having a semicircular or fan-shaped cross section, and when the closing pieces are combined in a cylindrical shape, a cone shape or a truncated cone shape, a guide tube is passed through the center of the cross section. The smooth blasting blasting method according to claim 3, wherein each of the closed pieces is formed so that a through hole is formed.

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