JP5824926B2 - Blasting method spacer that can be fixed in the explosive loading hole, and blasting method - Google Patents

Description

  The present invention relates to a blasting method spacer that can be fixed at an arbitrary angular position in an explosive loading hole, and a blasting method using this spacer.

  In the tunnel blasting method, a smooth blasting method is known in which an explosive having a diameter smaller than the hole diameter of the explosive loading hole is loaded to suppress the destruction energy more than necessary for the explosive. In this construction method, a technique is disclosed in which a hollow rod-like spacer closed at both ends is inserted into an explosive loading hole to reduce the internal space of the explosive loading hole, and granular explosive is loaded into the reduced internal space ( For example, see Patent Document 1).

  FIG. 11A is a diagram illustrating the spacer SP1 described in Patent Document 1. FIG. As shown in this figure, the spacer SP1 of Patent Document 1 has an oval shape that is sufficiently smaller than the explosive loading hole H. For this reason, the spacer SP1 is used in a state of being placed below the explosive loading hole H, and defines a space for inserting the granular explosive loading tube FL above the spacer SP1. Further, a triangular cross-section spacer SP2 shown in FIG. 11B is also known, but this spacer SP2 is also used in a state of being placed under the explosive loading hole H.

JP 2009-138955 A

  Each of the above-mentioned spacers is used in a state where it is placed under the explosive loading hole, and a space in which no explosive is loaded is formed in the lower portion of the explosive loading hole. Here, the space in which no explosive is loaded absorbs shock waves generated when the explosive explodes. Thereby, the shock wave is always easily propagated upward, and the propagation direction of the shock wave cannot be set to a desired direction. As a result, excavation along the planned excavation line was difficult.

  The present invention has been made in view of such circumstances, and an object of the present invention is to adjust the propagation direction of a shock wave generated when an explosive explodes, and to easily perform excavation along a planned excavation line. is there.

In order to achieve the above object, the present invention inserts a loading space into which an explosive is loaded and a non-loading space into which the explosive is not loaded into an internal space of the explosive loading hole. Formed and reduced by an external force when inserted into the explosive loading hole, and expanded by an elastic force when the external force is released, and a contact portion with the inner surface of the explosive loading hole is pressed against the inner surface of the explosive loading hole. A blasting method spacer fixed to the explosive loading hole ,
A cylindrical first cylindrical portion that forms a first non-loading space inside;
A cylindrical second cylindrical portion that forms a second non-loading space inside,
When the external force is released when the first cylindrical portion and the second cylindrical portion are brought close to each other by an external force, the first cylindrical portion and the second cylindrical portion are The second cylindrical portion is joined so as to be elastically separated .

  The spacer of the present invention is inserted into the explosive loading hole while being reduced by an external force. Thereafter, when the external force is released, the spacer expands in the explosive loading hole by the elastic force. Thus, the contact portion of the spacer with the inner surface of the explosive loading hole is pressed against the inner surface and takes a reaction force, so that the spacer itself can be fixed at an arbitrary angular position in the inner space of the explosive loading hole. Therefore, a non-loading space in which no explosive is loaded can be formed between the explosive loading space and the planned excavation line, and the shock wave at the time of the explosion can be made difficult to be transmitted to the rock on the planned excavation line side. As a result, excavation along the planned excavation line can be easily performed.

Also it has a first cylindrical portion cylindrical forming the first non-loading space inside, and a second cylindrical portion cylindrical to form a second unloaded space inside, wherein the first cylinder When the external force is released when the first cylindrical portion and the second cylindrical portion are brought close to each other by an external force , the first cylindrical portion and the second cylindrical portion Since the non-loading space is formed in a cylindrical shape by being joined so as to be elastically separated from the shape part, this granular explosive enters the non-loading space when using a granular explosive. Defects can be suppressed.

  In the spacer of the present invention, the first cylindrical portion is a flat cylindrical shape, the second cylindrical portion is a flat cylindrical shape, and one end portion on the long axis side in the cross section is the first cylindrical portion. The elastic portion is joined to one end portion on the long axis side of the shape portion, and the other end portions on the long axis side are joined to each other by an external force around the joint portion between the first tubular portion and the second tubular portion. Are bent so as to be close to each other, and when the external force is released, the other ends on the long axis side are preferably restored so as to be separated from each other. In this configuration, the two cylindrical portions are opened or closed around the joint portion by bending and restoring the elastic portion. And after inserting into an explosive loading hole in the state where cylindrical parts were closed, it is fixed to an explosive loading hole by opening cylindrical parts. For this reason, it can be inserted into the explosive loading hole and fixed with a simple structure.

In the spacer of the present invention, the first cylindrical portion, the front SL has a first projecting portion of the curved shape that protrudes toward the center of the explosive loading hole, said second cylindrical portion, the front SL explosive loading hole It is preferable to have the 2nd protrusion part of the curved shape protruded in the center side. In this configuration, the first projecting portion and the second projecting portion can reduce the volume of the loading space while securing the space through which the granular explosive loading tube passes. In addition, since the contact area between each protruding portion and the loading tube can be kept small, it is possible to easily handle the loading tube during insertion and withdrawal.

The present onset Ming is inserted into the explosive loading hole formed in the rock, and a non-loading space in which the the loading space explosive is loaded explosive is not loaded, formed in the internal space of the explosive loading hole, wherein When it is inserted into the explosive loading hole, it is reduced by external force, and when the external force is released, it expands by elastic force, and the contact portion with the inner surface of the explosive loading hole is pressed against the inner surface of the explosive loading hole, A blasting method using a blasting method spacer fixed in a hole,
Forming an explosive loading hole in the bedrock;
After insertion into the explosive loading hole in a state of being reduced to give the external force to the spacer, and the step of fixing the explosive loading hole by widening the spacer solving the external force,
At least the step of loading granular explosives into the loading space formed in the explosive loading hole by the spacer is characterized.

  According to the present invention, in the smooth blasting method using the spacer, the shock wave generated when the explosive explodes can be hardly propagated to the planned excavation line side and can be adjusted easily to propagate in the opposite direction. Drilling can be done easily.

(A), (b) is a perspective view which shows the spacer of this embodiment, respectively. It is a figure explaining the preparation procedure of a spacer, (a) is a figure explaining the paper cylinder used as a base, (b) is a figure explaining the produced spacer. It is a conceptual diagram explaining reduction and restoration of a spacer. It is a figure explaining the state which inserted and fixed the spacer in the explosive loading hole. It is a figure explaining an example of the relationship between an excavation planned line and the fixed angle of a spacer. It is a figure explaining the drilling of an explosive loading hole, (a) is a figure explaining an example of arrangement | positioning of an explosive loading hole, (b) is sectional drawing of an explosive loading hole. It is sectional drawing explaining the loading state to the explosive loading hole of a detonation part (parent die). (A) is sectional drawing explaining attachment to the explosive loading hole of a spacer, (b) is a conceptual diagram explaining the contraction state and restoration state of the spacer in an explosive loading hole. (A), (b) is sectional drawing explaining the state which loaded the granular explosive, respectively. It is a figure explaining other embodiment of a spacer. (A), (b) is a figure which shows the conventional spacer, respectively.

  Hereinafter, embodiments of the present invention will be described. First, the spacer of this embodiment will be described. As shown to Fig.1 (a), the spacer 1 is comprised by the elongate tubular member of the length suitable for the explosive loading hole excavated in a rock. For example, when the length of the explosive loading hole is 2 m, the total length of the spacer 1 is set to a length (a little less than 2 m) slightly shorter than the explosive loading hole.

  The spacer 1 is preferably made of a combustible material that burns when the granular explosive (increase die) in the explosive loading hole explodes. This is because if the spacer 1 is made of a nonflammable material, the rock mass excavated by blasting contains the nonflammable material, and this rock mass must be disposed of as industrial waste. Since the spacer 1 made of the combustible material is carbonized by the explosion of the explosive, the rock mass excavated by the blasting can be disposed as industrial waste. Further, since the spacer 1 is an elongated cylindrical member, it needs to have a rigidity that does not bend in the middle. Considering these, the spacer 1 of the present embodiment is made of a paper tube having a thickness of 2 mm.

  As shown in FIG. 1B, the cross-sectional shape of the spacer 1 has a substantially heart shape in which two rugby balls are combined at one end on the long axis side. As shown in FIG. 2 (a), the spacer 1 having such a cross-sectional shape is formed by forming three cuts Y1 to Y3 in the axial direction of the paper tube 1 ′ and bending the cuts Y1 to Y3. Easy to produce. For example, it can be produced by the following procedure.

  First, a cylindrical paper tube 1 ′ having an outer diameter substantially equal to the diameter of the explosive loading hole is prepared. Next, an inner notch Y1 is formed on the inner surface of the paper tube 1 'in the thickness direction along the axial direction, and a predetermined angle θ1 (about 80 °) is rotated counterclockwise from the inner notch Y1. A first outer notch Y2 is formed on the outer surface side of the position along the axial direction to the middle of the thickness direction, and along the axial direction on the outer surface side of the position rotated by a predetermined angle θ1 clockwise from the inner notch Y1. Then, the second outer cut Y3 is formed halfway in the thickness direction.

  If the three cuts Y1 to Y3 are formed, as indicated by the symbol F, the portion where the inner cut Y1 is formed is sufficiently pushed from the outer surface side toward the center of the paper tube 1 ′. When this portion is pushed to the opposing inner surface, the inner cut Y1, the first outer cut Y2, and the second outer cut Y3 are opened, and the paper tube 1 'bends around these cuts Y1 to Y3. As a result, the spacer 1 having a substantially heart-shaped cross-sectional shape as shown in FIG.

  In this spacer 1, a substantially elliptical space with both ends sharpened is formed on the left and right. And the 1st cylindrical part 2 which divides the 1st space 2 'of the left side in a figure, and the 2nd cylindrical part 3 which divides the 2nd space 3' of the right side in a figure are one ends by the side of the long axis in an ellipse The parts are connected to each other to define a substantially heart-shaped space. Although details will be described later, this space corresponds to a non-loading space in which no granular explosive is loaded. For this reason, the 1st cylindrical part 2 is corresponded to the cylindrical part which forms the 1st non-loading space inside, and the 2nd cylindrical part 3 is the cylindrical part which forms the 2nd non-loading space inside. Equivalent to.

  As shown in FIG. 3, in this spacer 1, since the 1st cylindrical part 2 and the 2nd cylindrical part 3 are joined at the one end parts by the side of the long axis in an elliptical cross section, each cylindrical part 2 , 3 are provided with elasticity. For this reason, it can be made to bend so that the other end parts of a major axis side may mutually adjoin each other centering on the junction part of the 1st cylindrical part 2 and the 2nd cylindrical part 3. FIG. For example, by gripping the tips of the cylindrical portions 2 and 3 corresponding to the cuts Y2 and Y3 by hand (applying an external force to the end far from the joint portion), the bending point indicated by the symbol A is centered. The outer curved portions 2a and 3a of the cylindrical portions 2 and 3 are bent, and the inner curved portions 2b and 3b are also bent. Thereby, the 1st cylindrical part 2 and the 2nd cylindrical part 3 can be brought close. Further, when the grasped hand is released, the curved portions 2a to 3b are restored in the return direction by the elastic force. Thereby, centering on the bending point A, it deform | transforms in the direction which the front-end | tip parts of each cylindrical part 2 and 3 mutually space apart. Therefore, each curved part 2a-3b which comprises each cylindrical part 2 and 3 is corresponded to the elastic part which produces the elastic force for restoring when an external force is released.

  The spacer 1 is reduced by an external force when inserted into the explosive loading hole H, and is expanded by an elastic force when the external force is released, and is fixed to the explosive loading hole H. As shown in FIG. 4, in the fixed state to the explosive loading hole H, the contact portion of the spacer 1 with the explosive loading hole H is pressed against the inner surface of the explosive loading hole H by the elasticity of the curved portions 2 a to 3 b. As a result, the spacer 1 obtains a reaction force and is fixed at an arbitrary angular position in the explosive loading hole H by friction between the contact portion and the inner surface. For example, the bending point A can be positioned and fixed in the 12 o'clock direction on the watch. Further, the bending point A can be positioned and fixed in the 3 o'clock direction, or can be positioned and fixed in the 9 o'clock direction.

  The spacer 1 is fixed to the explosive loading hole H, thereby dividing the internal space of the explosive loading hole H into a loading space 4 in which granular explosives are loaded and a non-loading space 5 in which granular explosives are not loaded. Specifically, the outer side than the spacer 1 is partitioned as the loading space 4, and the inner spaces 2 ′ and 3 ′ of the spacer 1 are partitioned as the non-loading space 5.

  Here, the inner curved portion 2b of the first cylindrical portion 2 is more than a first imaginary straight line L1 that connects the bending point A and the distal end portion (the other end portion on the long axis side) B1 of the first cylindrical portion 2. It protrudes toward the center of the explosive loading hole H. Similarly, the inner curved portion 3b of the second cylindrical portion 3 protrudes toward the center of the explosive loading hole H with respect to the second virtual straight line L2 that connects the bending point A and the distal end portion B2 of the second cylindrical portion 3. Has been. Such inner curved portions 2b and 3b function as a first projecting portion and a second projecting portion. By these inner curved portions 2b and 3b, the explosive loading hole H defines a loading space 4 having a cross-sectional shape and a substantially ginkgo shape.

  Part of the cylindrical loading tube FL for granular explosives enters a constricted portion in the loading space 4 having a substantially ginkgo shape. For this reason, it is possible to reduce the volume of the loading space 4 while ensuring a space through which the standardized diameter loading tube FL passes. For example, the area ratio (ratio of the drilling area of the explosive loading hole H and the cavity area inside the spacer) can be increased as compared with the conventional spacers SP1 and SP2. Thereby, the granular explosive in which the required amount per loading hole is defined can be loaded in a wide range in the explosive loading hole H.

  Moreover, since each inner side curved part 2b, 3b and the loading pipe | tube FL contact with a line, a contact area can be restrained small. As a result, it is possible to reduce friction with the spacer 1 when the loading tube FL is inserted or withdrawn, and the operation of the loading tube FL can be facilitated.

  As described above, the spacer 1 can be fixed at an arbitrary angular position in the explosive loading hole H. Thereby, as shown in FIG. 5, in each explosive loading hole HI to HQ (referred to as outermost explosive loading holes HI to HQ for convenience) close to the planned excavation line L3, a non-loading space formed inside the spacer 1 5 can be disposed between the loading space 4 and the planned excavation line L3. Therefore, when the explosive loaded in the outermost explosive loading holes HI to HQ explodes, the shock wave toward the excavation planned line L3 can be weakened by the non-loading space 5. As a result, the gas pressure associated with the explosion mainly acts on the side of the planned drilling line L3 from the outermost explosive loading holes HI to HQ, thereby suppressing the damage of the rock mass and the excessive excavation of the rock mass. it can.

  Hereinafter, the blasting method using the spacer 1 of this embodiment will be described.

  As shown in FIG. 6A, in this blasting method, first, a plurality of explosive loading holes H are formed in the rock (explosive loading hole forming operation). In this operation, a plurality of explosive loading holes HA to HQ are formed radially from the center of the planned excavation range in the rock. As shown in FIG.6 (b), the depth Z of each explosive loading hole H is predetermined, for example, is 1-2 m.

  If the plurality of explosive loading holes H are formed, the explosive loading holes H are loaded with the explosive portions 6 (priming portion loading operation). As shown in FIG. 7, in this operation, the initiation portion 6, also called a parent die, is loaded in the deepest portion of each explosive loading hole H. The detonator 6 includes a detonator 6b to which a conducting wire 6a is connected and an explosive 6c that explodes when energized to the detonator 6b. If the explosive loading holes H are loaded with the explosive parts 6, this operation is finished.

  Next, as shown in FIG. 8A, the spacer 1 is inserted and fixed to the outermost explosive loading holes HI to HQ among the explosive loading holes H (spacer fixing operation).

  In this operation, as shown by a one-dot chain line in FIG. 8B, the spacer 1 is contracted and inserted into the hole in the vicinity of the opening of the outermost explosive loading holes HI to HQ. For example, the first cylindrical portion 2 and the second cylindrical portion 3 are moved closer to each other by the operator's hand so that the spacer 1 can be smaller than the openings of the outermost explosive loading holes HI to HQ. The size in the cross-sectional direction is reduced and inserted into the hole. Since the inserted spacer 1 is freed from the external force by the operator, as shown by the solid line in FIG. 8B, each curved portion (elastic portion) constituting the first cylindrical portion 2 and the second cylindrical portion 3 is used. ) Open in a heart shape by the elasticity of 2a-3b.

  In this state, when the spacer 1 is attached to the upper portion of the outermost explosive loading holes HI to HQ, a downward force (gravity) acts on the spacer 1. However, even in such a case, since the elastic force of the spacer 1 resists gravity and opens both cylindrical portions 2 and 3 to the outside of the hole, the problem that the spacer 1 is displaced downward in the hole is suppressed. The When pushed to the end, the spacer 1 is fixed inside the hole by its elasticity. As described above, each spacer 1 is fixed at an angle at which the non-loading space 5 is disposed between the loading space 4 and the planned excavation line L3.

  If the spacer 1 is fixed to the outermost explosive loading holes HI to HQ, the granular explosive is loaded (explosive loading operation). In this operation, the loading tube FL for granular explosive is inserted to the deepest part of the explosive loading hole H to be loaded, and the loading tube FL is pulled back while loading the granular explosive. And loading with respect to the explosive loading hole H is complete | finished by loading a granular amount of granular explosive. Here, with respect to the outermost explosive loading holes HI to HQ, as shown in FIG. 9, the loading tube FL is inserted into the loading space 4 defined by the spacer 1 to load the granular explosive BM. In the present embodiment, the outermost explosive loading holes HI to HQ are covered with the inclusion 7 near the opening. As a result, the gas pressure at the time of explosion is efficiently applied to the rock mass.

  When the granular explosive BM is loaded in all the explosive loading holes H, the explosive is blown up and the rock is excavated (blasting operation). In this operation, the conducting wire 6a connected to the detonator 6b is energized. At this time, the timing is adjusted so that the detonator 6b closer to the central portion of the planned excavation range starts explosive earlier. Thereby, excavation can be performed in order from the central portion of the planned excavation range.

  As described above, since the loading space 4 is narrowed by the spacer 1 in the outermost explosive loading holes HI to HQ, the granular explosive BM is loaded over a wide range in the outermost explosive loading holes HI to HQ. . For this reason, at the time of an explosion, it is possible to effectively suppress a problem that the explosive force becomes locally strong and the excavation is greatly performed beyond the planned excavation line L3. Further, since the non-loading space 5 is arranged between the loading space 4 and the planned excavation line L3 by the spacer 1, it is possible to suppress a shock wave toward the planned excavation line L3. It is possible to effectively suppress the problem of being excavated far beyond. As a result, excavation with high accuracy can be performed at the boundary of the planned excavation range.

  As described above, in the spacer 1 of the present embodiment, the reaction force is obtained by the elastic force of each of the curved portions 2a to 3b, so that it can be fixed at an arbitrary angular position in the outermost explosive loading holes HI to HQ. Therefore, a non-loading space 5 in which no explosive is loaded can be formed between the explosive loading space 4 and the planned excavation line L3, and it is difficult to transmit a shock wave at the time of the explosion to the bedrock on the excavation planned line L3 side. As a result, excavation along the planned excavation line L3 can be easily performed.

  The spacer 1 has a first cylindrical portion 2 and a second cylindrical portion 3, and the cylindrical portions 2 and 3 are configured by curved portions (elastic portions) 2 a to 3 b having elasticity. Therefore, the problem that the granular explosive enters the cylindrical portions 2 and 3 can be prevented. Thereby, the propagation direction of the shock wave at the time of explosion can be adjusted. Furthermore, since these cylindrical parts 2 and 3 are joined in a heart shape, the cylindrical parts 2 and 3 are opened and closed around the joined part, thereby being inserted into the explosive loading hole H and fixed. Can be done. Furthermore, since each cylindrical part 2 and 3 has the inner curved part (protrusion part) 2b and 3b protruded to the center side of the explosive loading hole H, the space where the loading pipe | tube FL of a granular explosive passes is ensured. However, the volume of the loading space 4 can be reduced. In addition, since the contact area between each inner curved portion 2b, 3b and the loading tube FL can be kept small, the handling at the time of insertion and withdrawal of the loading tube FL can be facilitated.

  The above description of the embodiment is for facilitating the understanding of the present invention, and does not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof. For example, you may comprise as follows.

  In the above-described embodiment, the spacer 1 having the first cylindrical portion 2 and the second cylindrical portion 3 having an elliptical cross section is illustrated, but the spacer 1 is not limited to this shape.

  For example, as shown in FIG. 10, a corrugated plate-shaped (bellows-shaped) spacer 11 having peak portions 12 and valley portions 13 and 14 may be used. In this spacer 11, a relatively large peak 12 is formed at the center, and relatively small valleys 13 and 14 are formed at the left and right ends of the peak 12. Furthermore, ribs 15 and 16 that contact the inner surface of the hole are also formed at both ends in the width direction. Further, in the normal state, the interval between the ribs is determined to be wider than the diameter of the outermost explosive loading holes HI to HQ. When this spacer 11 is used, the space above the spacer 11 becomes the non-loading space 5, and the lower space becomes the loading space 4. A narrowed portion for passing the loading tube FL is formed below the peak portion 12.

  For example, the spacer 11 can be suitably made of a plate material made of engineer plastic (PET, PE, PP, etc.) having combustibility and elasticity. When the spacer 11 is inserted into the outermost explosive loading holes HI to HQ, the spacer 11 is reduced in the width direction so as to bring the ribs 15 and 16 at both ends closer by the operator's hands. In the inside of the hole, the spacer 1 is restored by the elasticity of the peak portion 12 and the valley portions 13 and 14, and the ribs 15 and 16 are pressed against the inner surface of the hole, so that a reaction force necessary for fixing is obtained.

  The spacer is not limited to the spacers 1 and 11 described above. For example, a styrofoam stick that has been processed so that its cross-sectional shape has a heart shape similar to that of the spacer 1 described above may be used as the spacer. In short, the spacer is reduced by an external force when inserted into the explosive loading hole H, and is expanded by an elastic force when the external force is released, and a contact portion with the inner surface of the explosive loading hole H is on the inner surface of the explosive loading hole H. What is necessary is just to be pressed and fixed to the explosive loading hole H.

  In addition, the first cylindrical portion 2 and the second cylindrical portion 3 in the spacer 1 described above may be configured in a flat cylindrical shape as well as an elliptical shape. For example, the cross sections of the cylindrical portions 2 and 3 may be in the form of cushions in which both short sides of the rectangle are replaced with arcs, or in the shape of flat hills partitioned by arcs and straight lines.

DESCRIPTION OF SYMBOLS 1 ... Spacer, 1 '... Cylindrical paper tube, 2 ... 1st cylindrical part, 2' ... 1st space, 2a ... Outer curved part of 1st cylindrical part, 2b ... Inner curve of 1st cylindrical part 3, second cylindrical portion, 3 ′, second space, 3 a, outer curved portion of the second cylindrical portion, 3 b, inner curved portion of the second cylindrical portion, 4, loading in which the granular explosive is loaded Space, 5 ... Non-loading space not loaded with granular explosive, 6 ... Explosion section, 6a ... Conducting lead, 6b ... Detonator, 6c ... Explosive, 7 ... Inclusion, 11 ... Spacer, 12 ... Mountain, 13 ... Valley Part, 14 ... trough part, 15 ... rib, 16 ... rib, Y1 ... inside cut, Y2 ... first outside cut, Y3 ... second outside cut, L1 ... first virtual straight line, L2 ... second virtual straight line, L3 ... Scheduled drill line, H (HA-HQ) ... Explosive loading hole, HI-HQ ... Outermost explosive loading hole

Claims (4)

Inserted into the explosive loading hole formed in the bedrock, a loading space in which the explosive is loaded and a non-loading space in which the explosive is not loaded are formed in the internal space of the explosive loading hole, and when inserted into the explosive loading hole The blasting is reduced by an external force and expanded by an elastic force when the external force is released, and the contact portion with the inner surface of the explosive loading hole is pressed against the inner surface of the explosive loading hole and fixed to the explosive loading hole. A spacer for the construction method,
A cylindrical first cylindrical portion that forms a first non-loading space inside;
A cylindrical second cylindrical portion that forms a second non-loading space inside,
When the external force is released when the first cylindrical portion and the second cylindrical portion are brought close to each other by an external force, the first cylindrical portion and the second cylindrical portion are A blasting method spacer, wherein the second cylindrical part is joined so as to be elastically separated . The first cylindrical portion is a flat cylindrical shape,
The second cylindrical portion is a flat cylindrical shape, and one end portion on the long axis side in the cross section is joined to one end portion on the long axis side of the first cylindrical portion,
The elastic portion is bent around the joint between the first cylindrical portion and the second cylindrical portion so that the other ends on the long axis side are brought close to each other by an external force, and the external force is released. The blasting method spacer according to claim 1 , wherein the spacer is restored so that the other ends on the long axis side are separated from each other. It said first tubular portion has a first projecting portion of the front Symbol curved shape that protrudes toward the center of the explosive loading hole,
It said second cylindrical portion, the spacer for blasting method according to claim 2, characterized in that it comprises a second projecting portion of the front Symbol curved shape that protrudes toward the center of the explosive loading hole. Inserted into the explosive loading hole formed in the bedrock, a loading space in which the explosive is loaded and a non-loading space in which the explosive is not loaded are formed in the internal space of the explosive loading hole, and when inserted into the explosive loading hole A blasting method that is reduced by an external force and expanded by an elastic force when the external force is released, and a contact portion with the inner surface of the explosive loading hole is pressed against the inner surface of the explosive loading hole and fixed to the explosive loading hole A blasting method using a spacer for
Forming an explosive loading hole in the bedrock;
After insertion into the explosive loading hole in a state of being reduced to give the external force to the spacer, and the step of fixing the explosive loading hole by widening the spacer solving the external force,
A blasting method comprising at least a step of loading a granular explosive into the loading space formed in the explosive loading hole by the spacer.

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