A method of in-situ extrusion forming of shaped charge in blasthole

Abstract

The application discloses a method for extruding and forming a shaped charge in a blast hole, and the method comprises the following steps: S1, the on-site device comprises three extruders, a co-extrusion die and three feeding pipes, and the three extruders are connected with the co-extrusion die through the feeding pipes; S2, the shaped charge is composed of explosive, a shell and a shaped charge plate, the explosive, the material for preparing the shell and the material for preparing the shaped charge plate are respectively fed into the three extruders, and then the extruded materials are transported into the co-extrusion die; S3, the extrusion nozzle of the co-extrusion die is inserted into the blast hole, the co-extrusion material is extruded into the blast hole, and the co-extrusion die is withdrawn from the blast hole, when the co-extrusion material in the blast hole reaches a set amount, the co-extrusion die stops working, and the extrusion nozzle of the co-extrusion die is completely withdrawn from the blast hole; and S4, after the co-extrusion material in the blast hole is hardened, the shaped charge is formed. The method is simple and convenient to operate, can quickly form the shaped charge in the blast hole, and realizes the integration and automation of the forming and charging of the shaped charge.

Description

Technical Field

[0001] This invention belongs to the field of tunnel blasting technology, specifically relating to a method for on-site extrusion forming of shaped charge explosives within a blast hole. Background Technology

[0002] Currently, smooth blasting technology is mainly used in tunnel excavation to control over- and under-excavation on the excavation profile and reduce damage to the surrounding rock. Smooth blasting typically employs measures such as reducing the blasting advance, increasing the density of boreholes, using air-gap charges, and decoupled charges to improve blasting effectiveness, but this also leads to problems such as low construction efficiency and increased costs. To address this issue, new technologies such as slotted blasting, slit-charge blasting, and shaped charge blasting have been developed both domestically and internationally. These technologies, based on traditional smooth blasting and pre-splitting blasting, regulate the distribution of explosive energy by improving the shape and packaging of the explosive charge or changing the cross-sectional shape of the borehole, thereby increasing the degree of rock damage in one direction while reducing the degree of rock damage in another.

[0003] However, changing the shape of the borehole would alter the current drilling methods, making it difficult to meet construction efficiency requirements in terms of both drilling efficiency and the accuracy of borehole shape layout. Secondly, changing the shape of the explosive charge, such as using shaped charge charges or slotted charge charges with PVC outer casings, presents challenges in accurately positioning the energy enhancement direction of the charge. Furthermore, the cost of these charges is significantly higher than current packaging methods, requiring the manufacture of shaped or slotted charge charges in a factory before transporting them to the tunnel for installation, making the process extremely complex. Therefore, none of these new technologies have been widely adopted in actual engineering projects.

[0004] Currently, the technology of directly injecting explosives into boreholes for on-site mixing is developing rapidly. However, this technology can only extrude pure explosive strips into cylindrical shapes and cannot automatically form shaped charge packages. Therefore, there is currently no technology that can directly extrude shaped charge packages into boreholes using a charging machine. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for on-site extrusion forming of shaped charge charges within a borehole. This method is simple, easy to operate, and can quickly form shaped charge charges within a borehole, achieving integration and automation of shaped charge charge forming and loading.

[0006] The technical solution adopted to achieve the above-mentioned objectives of this invention is as follows:

[0007] A method for on-site extrusion forming of shaped charge explosive charges within a borehole includes the following steps:

[0008] S1. Constructing an on-site forming device for shaped charge explosives:

[0009] The on-site forming device for shaped charge explosives includes three extruders, a co-extrusion die, and three feed pipes. The three extruders are connected to the co-extrusion die through the feed pipes.

[0010] S2. The shaped charge consists of explosive, outer shell and shaped charge sheet. The explosive, the material for preparing the outer shell and the material for preparing the shaped charge sheet are respectively fed into three extruders for extrusion. After extrusion, the explosive, the material for preparing the outer shell and the material for preparing the shaped charge sheet are transported to the co-extrusion die through the feed pipe.

[0011] S3. Insert the extrusion nozzle of the co-extrusion die into the borehole. The extrusion nozzle of the co-extrusion die co-extrudes the explosive, the material for preparing the outer shell, and the material for preparing the energy-concentrating sheet into the borehole while withdrawing from the borehole. When the set amount of co-extruded material is co-extruded into the borehole, the co-extrusion die stops working and the extrusion nozzle of the co-extrusion die is completely withdrawn from the borehole.

[0012] S4. After the co-extruded material in the blast hole hardens, it forms a shaped charge explosive.

[0013] Furthermore, the center of the shaped charge is explosive, the cross-section of which is "waist-shaped" or "rounded star-shaped", the shaped charge is arc-shaped or "V-shaped", the outer shell is hollow, the explosive is located in the outer cavity, the outer contour of the outer shell cross-section is circular, the inner contour of the outer shell cross-section is "waist-shaped" or "rounded star-shaped", the shaped charge is located between the outer shell and the explosive, and the shaped charge is attached to the bend of the explosive.

[0014] Furthermore, the average density of the material used to prepare the shell is less than 1 g / cm³. 3 It can harden rapidly in both water and air.

[0015] Furthermore, the material used to prepare the energy-concentrating sheet is a mixture of metal wire and adhesive, wherein the density of the metal used in the metal wire is not less than 2.7 g / cm³. 3 The diameter of the metal wire is no greater than 1mm.

[0016] Compared with the prior art, the beneficial effects and advantages of the present invention are as follows:

[0017] 1. This invention, by changing the shape of the extruder nozzle or controlling the partial feeding of multiple feed pipes, can easily extrude explosive strips with circular or complex cross-sections that meet design requirements. This solves the problem of the difficulty in using conventional shaped charge explosives to blast rocks inside blast holes, thus improving blasting efficiency and blasting effect.

[0018] 2. Compared with methods such as slotting blasting, slit-cutting explosive charge blasting, and shaped charge blasting, this method can save a significant amount of time in slotting blast holes and loading explosives.

[0019] 3. The method of the present invention can be conveniently applied to the on-site mixing technology of explosives.

[0020] 4. This method directly extrudes the material of the shaped charge into the blast hole, which hardens rapidly to become the shaped charge. There is no need to package the explosive, saving packaging time. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a shaped charge explosive.

[0022] Figure 2 This is a schematic diagram of the main structure of the co-extrusion die.

[0023] Among them, 1-explosive, 2-shell, 3-shaped charge, 4-first chamber, 5-second chamber, and 6-third chamber. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] Example 1

[0026] S1. During tunnel blasting excavation, it is necessary to form [something] in the blast holes. Figure 1 The shaped charge shown is a symmetrical structure consisting of explosive, outer shell, and shaped charge plates. The outer shell is hollow, with a circular outer contour and a four-pointed star-shaped inner contour. The explosive has a four-pointed star-shaped cross-section and is located at the center of the outer shell. The shaped charge plates are arc-shaped, and there are four of them. The four shaped charge plates are located between the outer shell and the explosive, and are attached to the four bends of the explosive.

[0027] S2. Constructing an on-site forming device for shaped charge explosives:

[0028] The on-site forming device for shaped charge explosive packages includes extruder A, extruder B, extruder C, co-extrusion die, feed line A, feed line B, and feed line C;

[0029] The co-extrusion die includes the co-extrusion die body and the extrusion nozzle. The structure of the co-extrusion die body is as follows: Figure 2As shown, the co-extrusion die body has a symmetrical structure. The outer contour of the co-extrusion die body is cylindrical. The co-extrusion die body is divided into a first chamber 4, a second chamber 5, and a third chamber 6. The cross-section of the first chamber 4 is a "four-pointed star" shape. The first chamber 4 is located at the center of the co-extrusion die body. There are two third chambers 6. The outer contour of the cross-section of the structure formed by the two third chambers 6 is circular. The inner contour of the cross-section of the structure formed by the two third chambers 6 is a "four-pointed star" shape. The symmetry plane of the two third chambers 6 is the same as the symmetry plane of the first chamber 4. The second chamber 5 is arc-shaped. There are four second chambers 5. The four second chambers 5 are respectively attached to the four bends of the first chamber 4. The extrusion nozzle is a hollow tubular structure. One end face of the extrusion nozzle is connected to the end face of the structure formed by the two third chambers.

[0030] Extruder A is connected to the two first chambers through feed pipe A, extruder B is connected to the second chamber through feed pipe B, and extruder C is connected to the third chamber through feed pipe C;

[0031] S3. The explosive selected is a gel-like emulsion explosive. The material used to prepare the outer shell is a mixture of polyurethane prepolymer, foaming agent, stabilizer, and quartz sand, with a density of 0.5 g / cm³. 3 It can harden rapidly in both water and air. The material used to prepare the energy-concentrating sheet is a mixture of copper wire and epoxy resin. The copper wire is 3cm long and 1mm in diameter.

[0032] S4. The materials for preparing the outer shell and the materials for preparing the energy-concentrating sheet are respectively fed into three extruders for extrusion. The explosive enters the first chamber 4 through the feed pipe A, the materials for preparing the outer shell enter the two third chambers 6 through the feed pipe C, and the materials for preparing the energy-concentrating sheet enter the four second chambers 5 through the feed pipe B.

[0033] S5. Insert the extrusion nozzle of the co-extrusion die into the borehole. The extrusion nozzle of the co-extrusion die co-extrudes the explosive, the material for preparing the outer shell, and the material for preparing the energy-concentrating sheet into the borehole while withdrawing from the borehole. When the set amount of co-extruded material is co-extruded into the borehole, the co-extrusion die stops working and the extrusion nozzle of the co-extrusion die is completely withdrawn from the borehole.

[0034] S6. After the co-extruded material in the blast hole hardens rapidly, it forms a shaped charge explosive.

Claims

1. A method for on-site extrusion forming of shaped charge explosive charges within a borehole, characterized in that... Includes the following steps: S1. Constructing an on-site forming device for shaped charge explosives: The on-site forming device for shaped charge explosives includes three extruders, a co-extrusion die, and three feed pipes. The three extruders are connected to the co-extrusion die through the feed pipes. S2. The shaped charge is composed of explosive (1), shell (2) and shaped charge (3). The explosive (1), the material for preparing the shell (2) and the material for preparing the shaped charge (3) are respectively fed into three extruders for extrusion. After extrusion, the explosive (1), the material for preparing the shell (2) and the material for preparing the shaped charge (3) are transported to the co-extrusion die through the feed pipe. The center of the shaped charge is explosive (1), the cross-section of explosive (1) is "waist" or "rounded star", the shaped charge (3) is arc or "V" shaped, the outer shell (2) is hollow, the explosive (1) is located in the cavity of the outer shell (2), the outer contour of the cross-section of the outer shell (2) is circular, the inner contour of the cross-section of the outer shell (2) is "waist" or "rounded star", the shaped charge (3) is located between the outer shell (2) and the explosive (1), and the shaped charge (3) is attached to the bend of the explosive (1); S3. Insert the extrusion nozzle of the co-extrusion mold into the borehole. The extrusion nozzle of the co-extrusion mold co-extrudes the explosive (1), the material for preparing the outer shell (2) and the material for preparing the energy-concentrating sheet (3) into the borehole while withdrawing from the borehole. When the set amount of co-extruded material is co-extruded into the borehole, the co-extrusion mold stops working and the extrusion nozzle of the co-extrusion mold is completely withdrawn from the borehole. S4. After the co-extruded material in the blast hole hardens, it forms a shaped charge explosive.

2. The method for on-site extrusion forming of shaped charge explosive charges within a borehole according to claim 1, characterized in that: The material used to prepare the outer shell (2) has an average density of less than 1 g / cm³. 3 It can harden rapidly in both water and air.

3. The method for on-site extrusion forming of shaped charge explosive charges within a borehole according to claim 1, characterized in that: The material used to prepare the energy-concentrating sheet (3) is a mixture of metal wire and adhesive, wherein the density of the metal used in the metal wire is not less than 2.7 g / cm³. 3 The diameter of the metal wire is no greater than 1mm.

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