Lotus root type energy-gathering smooth blasting method for tunnel surrounding rock

Abstract

The application discloses a lotus root type energy-gathering smooth blasting method for tunnel surrounding rock, which comprises the following steps: drilling a peripheral hole on the tunnel surrounding rock and placing an inner corresponding track; according to the longitudinal depth of the peripheral hole, a plurality of energy-gathering explosive sections are connected in series to a corresponding length; an energy-gathering groove on the energy-gathering explosive section is correspondingly clamped on the track, and the energy-gathering explosive section is pushed to the bottom of the peripheral hole along the track; the track is separated from the peripheral hole, and each energy-gathering explosive section is detonated to blast the tunnel surrounding rock. The application has the advantages that: the energy-gathering explosive section adopts an openable and closable cavity structure, which is convenient for quick charging and then buckling and locking, and improves the charging efficiency; the openable and closable cavity structure in the lotus root shape can save the charging amount, and the middle part is more than the two ends, so that the blasting energy is concentrated in the middle part; the guide rail is arranged to guide the openable and closable cavity to the predetermined position, and the openable and closable cavity and the short pipe are fixed in position by the air bag inflation mode.

Description

Technical Field

[0001] This invention belongs to the field of tunnel excavation technology, specifically relating to a lotus root-type focused energy smooth blasting method for tunnel surrounding rock. Background Technology

[0002] Currently, smooth blasting technology is widely used in tunnel construction. Smooth blasting is a blasting technique that controls the excavation profile of the rock mass. It involves a series of measures to correctly drill and blast the surrounding areas of the excavation, with the peripheral holes being the last to detonate. Pre-splitting blasting, on the other hand, detonates the peripheral holes first, using a slightly higher linear charge density than smooth blasting, and a slightly smaller spacing between the peripheral holes.

[0003] The conventional smooth blasting currently being used has the following problems:

[0004] (1) The spacing between blast holes in a light blasting operation is 40-50cm. Too many holes are laid out, too many holes are drilled, and the drilling operation takes too long. (2) The dense arrangement of blast holes and the large amount of explosive charge can easily cause cracks or cavities in the surrounding rock at the location of the explosive charge, affecting the stability of the surrounding rock and even causing collapse. (3) Over-excavation often occurs, increasing the amount of concrete lining and raising construction costs. Over-excavation is the fatal "culprit" in tunnel construction and excavation. (4) The current shaped charge tube loading also has inconveniences, as the shaped charge tube needs to be inserted into the explosive to complete the loading.

[0005] Therefore, those skilled in the art urgently need new blasting techniques to overcome the shortcomings of the above-mentioned smooth blasting techniques. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by providing a lotus root-shaped shaped charge smooth blasting method for tunnel surrounding rock. This blasting method utilizes an openable cavity to facilitate the charging process, avoiding the inconvenience of inserting a tube into the explosive section to squeeze in the explosive. By using a lotus root-shaped openable cavity, the explosive can be concentrated in the middle, reducing the amount of explosive at both ends. Furthermore, the lotus root-shaped shaped charge explosive section can be guided into place and fixed by guide rails and airbags to prevent displacement and achieve precise blasting along the contour line.

[0007] The objective of this invention is achieved through the following technical solutions:

[0008] A lotus root-shaped shaped charge smooth blasting method for tunnel surrounding rock, characterized in that the blasting method includes the following steps:

[0009] S1: Drill peripheral holes in the surrounding rock of the tunnel; insert the track into the corresponding peripheral holes;

[0010] S2: Based on the longitudinal depth of the peripheral holes, several shaped charge segments are connected in series to the corresponding length; wherein, each shaped charge segment consists of an openable cavity and explosives filled in the openable cavity, the openable cavity including an upper cover and a lower cover, one side of the upper cover and the lower cover being hinged, and the other side being fastened by a protrusion and a groove; adjacent shaped charge segments are connected in series by a short tube, and a detonating cord connecting adjacent openable cavities is arranged inside the short tube; the openable cavity is cylindrical in shape and gradually tapers to a conical shape at both ends, and two shaped charge grooves are symmetrically arranged on the outer wall of the openable cavity, the shaped charge grooves being concave triangular grooves;

[0011] S3: Place the shaped charge slot on the shaped charge section onto the track, and push the shaped charge section along the track to the bottom of the peripheral hole;

[0012] S4: Pull the track out of the peripheral hole and detonate each of the shaped charge sections to blast the surrounding rock of the tunnel.

[0013] The upper cover and the lower cover are respectively provided with rubber pads on their snap-fit ​​side edges to achieve a sealing snap-fit. The protrusions are fixedly arranged at intervals along the snap-fit ​​side edge of the lower cover, and the grooves are opened at intervals along the snap-fit ​​side edge of the upper cover, and the positions of the protrusions and the grooves correspond one-to-one.

[0014] The end of the protrusion is spherical, and the groove is a semi-circular groove that matches the end of the protrusion.

[0015] The end of the openable cavity is provided with a small hole for the detonating cord to pass through; and the end of the openable cavity is provided with a shaft hole, and the end of the short tube is provided with a pivot, and the pivot is assembled with the shaft hole at the end of the openable cavity to form a hinged connection.

[0016] The track includes an end fixing device fixed to the opening of the peripheral hole and a longitudinal track extending from the end fixing device into the peripheral hole. The longitudinal track has a cross-sectional shape adapted to the energy-concentrating groove. The longitudinal track is arranged along the blasting profile of the surrounding rock of the tunnel so that the line connecting the two energy-concentrating grooves of the openable cavity is tangent to the blasting profile.

[0017] The short tube is covered with an airbag on its outside. A longitudinal inflation tube is arranged inside the openable cavity and the short tube, and the longitudinal inflation tube is connected to the airbag. In step S3, after the shaped charge section is pushed to the bottom of the peripheral hole, each airbag is inflated through the longitudinal inflation tube to make the airbag expand and support the inner wall of the peripheral hole to ensure that the position of the short tube and the openable cavity is fixed. Then the track is pulled out from the peripheral hole.

[0018] The length of the shaped charge section is between 90 and 110 cm.

[0019] The advantages of this invention are:

[0020] (1) The shaped charge section adopts an openable cavity structure, which facilitates fast loading and locking, thereby improving loading efficiency.

[0021] (2) The lotus root-shaped openable cavity structure can save the amount of explosives, with more in the middle and less at both ends, thus concentrating the explosive energy in the middle.

[0022] (3) By connecting the lotus root-shaped shaped explosive segments in series, it is possible to quickly fill them into the surrounding holes; by setting guide rails, the openable cavity can be guided to the predetermined position, and the position of the openable cavity and the short tube can be fixed by the airbag expansion method. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the shaped charge smooth blasting structure on the surrounding rock of the tunnel in this invention;

[0024] Figure 2 This is a schematic diagram showing the series connection of the lotus root-shaped shaped explosive segments in this invention;

[0025] Figure 3 In this invention Figure 2 AA diagram in the image;

[0026] Figure 4 In this invention Figure 2 AA diagram in the image;

[0027] Figure 5 This is a detailed partial view of the adjacent openable cavities in this invention, connected by a short tube, with the airbag not inflated.

[0028] Figure 6 This is a partial detailed view of the adjacent openable cavities in this invention, connected by a short tube and with the airbag inflated.

[0029] Figure 7 For the present invention Figure 3 Detailed view of section B in the image. Detailed Implementation

[0030] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art:

[0031] like Figure 1-7 The markings in the diagram are as follows: 1. Tunnel surrounding rock, 2. Peripheral hole, 3. shaped charge section, 4. Openable cavity, 41. Upper cover, 42. Lower cover, 5. Short pipe, 6. Shaped charge groove, 7. Hinge, 8. Groove, 9. Protruding column, 10. Rubber pad, 11. Rotating shaft, 12. Shaft hole, 13. Airbag, 14. Longitudinal track, 15. Longitudinal inflation pipe.

[0032] Example: Figure 1-7 As shown, this embodiment specifically relates to a lotus root-type shaped charge smooth blasting method for tunnel surrounding rock, which includes the following steps:

[0033] (S1) As Figure 1 As shown, peripheral holes 2 are drilled in the surrounding rock 1 of the tunnel, and the peripheral holes 2 are arranged along the tunnel outline. A track is pre-installed within each peripheral hole 2. This track specifically includes an end fixing device fixed at the opening of the peripheral hole 2 and a longitudinal track 14 extending from the end fixing device into the peripheral hole 2. It should be noted that the longitudinal track 14 is arranged along the blasting outline of the surrounding rock of the tunnel. This longitudinal track 14 is used to guide the shaped charge slot 6 on the openable cavity 4. The lotus root-shaped shaped charge sections 3 are not perfectly straight; therefore, the longitudinal track 14 is used to guide and limit their movement.

[0034] (S2) For example Figure 1 , 2 As shown, based on the longitudinal depth of the peripheral hole 2, several shaped charge segments 3 are connected in series to the same length as the longitudinal depth. In this embodiment, the longitudinal depth of the peripheral hole 2 is selected as 3 meters, and the length of each shaped charge segment 3 is 1 meter. Therefore, connecting three sets of shaped charge segments 3 in series can fill the peripheral hole 2.

[0035] The shaped charge section 3 is specifically composed of an openable cavity 4 and explosives filled within it. To facilitate rapid loading of the explosives into the cavity, the openable cavity 4 employs a flip-top structure, including an upper cover 41 and a lower cover 42. One side edge of the upper cover 41 and the lower cover 42 is hinged together using hinges 7, while the other side edge is fastened together using protrusions 9 and grooves 8. Specifically, to ensure the sealing of the fastening between the upper cover 41 and the lower cover 42, a rubber gasket 10 is longitudinally positioned between their joints. Protrusions 9 are fixedly arranged at intervals along the fastening side edge of the lower cover 42, and grooves 8 are spaced apart along the fastening side edge of the upper cover 41, with the positions of the protrusions 9 and grooves 8 corresponding one-to-one. The ends of the protrusions 9 are spherical, and the grooves 8 are semi-circular grooves that match the ends of the protrusions 9.

[0036] like Figure 2 As shown, the openable cavity 4 is cylindrical in shape and gradually tapers to a conical shape at both ends, resembling a lotus root. By adopting this lotus root structure, explosives can be concentrated in the middle part, while the ends gradually taper, thus saving the amount of explosives required. Figure 3 , 4 As shown, the cross-section of the openable cavity 4 can be either of the two forms shown. Two energy-concentrating grooves 6 are symmetrically arranged on the upper cover 41 and the lower cover 42, respectively. The energy-concentrating grooves 6 are concave triangular grooves. Due to the axial convergence and collision of the explosion products and shock waves generated by the explosion of the explosive near the energy-concentrating grooves 6, a high-pressure, high-density, high-speed airflow is formed and ejected outward along the axial direction. This airflow is called the energy-concentrating jet. It should be noted that the longitudinal track 14 has a cross-sectional shape adapted to the energy-concentrating grooves 6. The longitudinal track 14 is arranged along the blasting contour line of the tunnel surrounding rock 1 so that the line connecting the two energy-concentrating grooves 6 of the openable cavity 4 is tangent to the blasting contour line and remains in a fixed position.

[0037] like Figure 2-6 As shown, adjacent shaped charge sections 3 are connected in series via short pipes 5, and detonating cords (not shown in the figure) connecting the explosives in adjacent openable cavities 4 are arranged inside the short pipes 5. Figure 5 As shown, the end of the openable cavity 4 has a small hole for the detonating cord to pass through; and the end of the openable cavity is provided with a shaft hole 12, and the end of the short tube 5 is provided with a pivot 11, which is assembled with the pivot hole 12 at the end of the openable cavity 4 to form a hinged connection. Through the hinge between the short tube 5 and the openable cavity 4, the connection of the detonating cord can be satisfied on the one hand, and a small range of bending can be formed to adapt to the changes in the curvature of the tunnel on the other hand.

[0038] In addition, an airbag 13 is wrapped around the outside of the short tube 5, and a longitudinal inflation tube 15 is arranged inside the openable cavity 4 and the short tube 5. A branch tube is branched on the longitudinal inflation tube 15 and connected to the airbag 13. The airbag can be inflated by an external air compressor through the longitudinal inflation tube 15.

[0039] (S3) Place the shaped charge slot 6 on the shaped charge section 3 onto the longitudinal track 14, and push the shaped charge section 3 along the longitudinal track 14 to the bottom of the peripheral hole 2; after it is in place, inflate each airbag 13 through the longitudinal inflation pipe 15 so that the airbag 13 expands and supports the inner wall of the peripheral hole 2, thereby ensuring that the overall position of each shaped charge section 3 is fixed and does not shift through the friction between the airbag 13 and the inner wall of the peripheral hole 2. Figure 6 As shown, the inflated airbag 13 fills the space between the adjacent openable cavities 4.

[0040] (S4) After ensuring that the positions of each shaped charge section 3 remain fixed, release the end fixing device of the track from the opening and pull the longitudinal track 14 out of the peripheral hole. Then detonate each shaped charge section 3 to blast the surrounding rock 1 of the tunnel.

[0041] The beneficial effects of this embodiment are:

[0042] (1) The shaped charge section adopts an openable cavity structure, which facilitates fast loading and locking, thereby improving loading efficiency.

[0043] (2) The lotus root-shaped openable cavity structure can save the amount of explosives, with more in the middle and less at both ends, thus concentrating the explosive energy in the middle.

[0044] (3) By connecting the lotus root-shaped shaped explosive segments in series, it is possible to quickly fill them into the surrounding holes; by setting guide rails, the openable cavity can be guided to the predetermined position, and the position of the openable cavity and the short tube can be fixed by the airbag expansion method.

Claims

1. A method for lotus root-shaped shaped charge smooth blasting on tunnel surrounding rock, characterized in that... The blasting method includes the following steps: S1: Drill peripheral holes in the surrounding rock of the tunnel; insert the track into the corresponding peripheral holes; S2: Based on the longitudinal depth of the peripheral holes, several shaped charge segments are connected in series to the corresponding length; wherein, each shaped charge segment consists of an openable cavity and explosives filled in the openable cavity, the openable cavity including an upper cover and a lower cover, one side of the upper cover and the lower cover being hinged, and the other side being fastened by a protrusion and a groove; adjacent shaped charge segments are connected in series by a short tube, and a detonating cord connecting adjacent openable cavities is arranged inside the short tube; the openable cavity is cylindrical in shape and gradually tapers to a conical shape at both ends, and two shaped charge grooves are symmetrically arranged on the outer wall of the openable cavity, the shaped charge grooves being concave triangular grooves; S3: Place the shaped charge slot on the shaped charge section onto the track, and push the shaped charge section along the track to the bottom of the peripheral hole; The track includes an end fixing device fixed to the opening of the peripheral hole and a longitudinal track extending from the end fixing device into the peripheral hole. The longitudinal track has a cross-sectional shape adapted to the energy-concentrating slot. The longitudinal track is arranged along the blasting profile of the surrounding rock of the tunnel so that the line connecting the two energy-concentrating slots of the openable cavity is tangent to the blasting profile. S4: Pull the track out of the peripheral hole and detonate each of the shaped charge sections to blast the surrounding rock of the tunnel.

2. The lotus root-type shaped charge smooth blasting method for tunnel surrounding rock according to claim 1, characterized in that... The upper cover and the lower cover are respectively provided with rubber pads on their snap-fit ​​side edges to achieve a sealing snap-fit. The protrusions are fixedly arranged at intervals along the snap-fit ​​side edge of the lower cover, and the grooves are opened at intervals along the snap-fit ​​side edge of the upper cover, and the positions of the protrusions and the grooves correspond one-to-one.

3. A method for lotus root-shaped shaped charge smooth blasting on tunnel surrounding rock according to claim 2, characterized in that... The end of the protrusion is spherical, and the groove is a semi-circular groove that matches the end of the protrusion.

4. A method for lotus root-shaped shaped charge smooth blasting on tunnel surrounding rock according to claim 2, characterized in that... The end of the openable cavity is provided with a small hole for the detonating cord to pass through; and the end of the openable cavity is provided with a shaft hole, and the end of the short tube is provided with a pivot, and the pivot is assembled with the shaft hole at the end of the openable cavity to form a hinged connection.

5. A method for lotus root-shaped shaped charge smooth blasting on tunnel surrounding rock according to claim 1, characterized in that... The short tube is covered with an airbag on its outside. A longitudinal inflation tube is arranged inside the openable cavity and the short tube, and the longitudinal inflation tube is connected to the airbag. In step S3, after the shaped charge section is pushed to the bottom of the peripheral hole, each airbag is inflated through the longitudinal inflation tube to make the airbag expand and support the inner wall of the peripheral hole to ensure that the position of the short tube and the openable cavity is fixed. Then the track is pulled out from the peripheral hole.

6. A method for lotus root-type shaped charge smooth blasting on tunnel surrounding rock according to claim 1, characterized in that... The length of the shaped charge section is between 90 and 110 cm.

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