Channel foundation pit negative excavation presplitting blasting charging structure based on distributed perforating bullet combination

Abstract

The invention discloses a channel foundation pit negative excavation presplitting blasting charging structure based on distributed perforating bullet combination, which comprises a perforating bullet rack and perforating bullets, the perforating bullet rack is mounted in a presplitting hole, a plurality of positioning holes are formed in the perforating bullet rack at intervals along the height direction, the distance between every two adjacent positioning holes is 40-60cm, and the perforating bullets are filled in the positioning holes; the multiple pre-splitting holes are distributed along a preset track, and the distance between every two adjacent pre-splitting holes is 1-1.2 m; on one perforating bullet frame, the jet flow directions of the multiple perforating bullets alternately face the first side and the second side of the pre-splitting direction, and the pre-splitting direction is the direction of the connecting line between every two adjacent pre-splitting holes; in every two adjacent pre-splitting holes, the flow directions of the perforating bullets at the same height are opposite. According to the method, the perforating bullets arranged at multiple points are used for presplitting blasting, the damage to the reserved rock mass is small, and the flatness of the presplitting surface is high; and the perforating bullets and the perforating bullet rack are prefabricated products, so that centralized storage and management are facilitated, and field assembly is simple and convenient.

Description

Technical Field

[0001] The invention belongs to the technical field of blasting excavation, and relates to a negative excavation pre-splitting blasting charging structure for a waterway foundation pit based on a distributed perforating bullet combination. Background Art

[0002] In the negative excavation construction of the waterway foundation pit, the outer contour of the foundation pit is generally controlled by pre-splitting blasting. Usually, the prefabricated PVC pipe is filled with a shaped hood and emulsion explosives, and then loaded into the blastholes set in the pre-splitting area, and the pre-splitting surface is formed by bidirectional linear shaped blasting. There are the following problems:

[0003] (1) Bidirectional linear energy blasting uses emulsion explosives, which have low detonation velocity and poor energy-gathering effect, and are not easy to form through cracks. When forming linear pre-cracks, the bidirectional linear energy blasting method causes great damage to the retained rock mass and has poor flatness, which has an adverse effect on the quality of the slope rock mass formed by excavation and the control of bedrock blasting vibration.

[0004] (2) The spacing between blastholes is between 0.6 and 0.8 m. The smaller the spacing, the higher the density of blastholes and the larger the construction volume.

[0005] (3) Explosives need to be loaded on site and the centering in the blast hole is not accurate.

[0006] In summary, how to prevent a large number of blasting cracks from occurring in the slope rock mass during pre-splitting blasting, ensure that the integrity of the rock mass is not destroyed, and at the same time reduce excessive over-excavation and reduce the construction volume is a technical challenge in negative excavation blasting construction of waterway foundation pits. Summary of the invention

[0007] Purpose of the invention: The purpose of the present invention is to provide a channel foundation pit negative excavation pre-splitting blasting charging structure based on a distributed perforating bullet combination to solve one or more problems existing in the prior art.

[0008] Technical solution: The present invention provides a negative excavation pre-splitting blasting charging structure for a waterway foundation pit based on a distributed perforating bullet combination, comprising:

[0009] A perforating bomb rack is installed in the pre-splitting hole. A plurality of positioning holes are arranged on the perforating bomb rack at intervals along the height direction, and the spacing between two adjacent positioning holes is 40 to 60 cm. There are multiple pre-splitting holes, which are arranged along a predetermined trajectory, and the spacing between adjacent pre-splitting holes is 1 to 1.2 m.

[0010] Perforating bullets are loaded into the positioning holes;

[0011] Wherein, on a perforating charge rack, the jet directions of a plurality of perforating charges are alternately oriented toward a first side and a second side of a pre-splitting direction, wherein the pre-splitting direction is the direction of a line connecting every two adjacent pre-splitting holes;

[0012] In two adjacent pre-splitting holes, the perforating bullet jets at the same height have opposite directions.

[0013] Furthermore, the perforating charge rack is an integral or multi-section structure. When it is a multi-section structure, perforating charge racks of different lengths are combined and connected according to the depth of the pre-splitting hole.

[0014] Furthermore, the pre-splitting hole includes a blast hole and two grooves, the two grooves are arranged at the edge of the blast hole and are located in the pre-splitting direction; the perforating charge holder is arranged in a cylindrical shape, the diameter of the perforating charge holder is smaller than the diameter of the inscribed circle of the pre-splitting hole, and a positioning block is provided on the outer wall of the perforating charge holder, the positioning block matches the shape of the groove, so that the perforating charge holder is located in the central position of the pre-splitting hole.

[0015] Furthermore, the direction of the positioning hole is the same as the direction of the positioning block, and the positioning block is arranged at the upper end and the lower end of the perforating charge holder.

[0016] Furthermore, the groove is configured as a V-shaped groove or a rectangular groove. When configured as a V-shaped groove, the angle of the groove is 30° to 60°.

[0017] Furthermore, the depth of the groove is 10±2 mm.

[0018] Furthermore, the positioning hole includes a large hole and a small hole, the perforating bullet is conical, the small diameter end of the perforating bullet is arranged in the small hole, the large diameter end of the perforating bullet is arranged in the large hole, and the large diameter end and the small diameter end of the perforating bullet have portions exposed outside the contour of the perforating bullet frame.

[0019] Furthermore, a deformation slit is provided at the periphery of the large hole, and a positioning groove is provided at the large diameter end of the perforating bullet; when the perforating bullet is assembled into the positioning hole, the deformation slit can undergo elastic deformation, and the positioning groove is inserted into the inner wall of the large hole.

[0020] Furthermore, the deformation seam is arc-shaped.

[0021] Furthermore, a detonating wire is arranged at the detonating charge of each perforating bullet, and the detonating wire passes through the inside of the perforating bullet rack to prevent the detonating wire from breaking when the perforating bullet rack is placed.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0023] (1) Perforating bullets use high-detonation-velocity explosives, which have good energy-gathering effects and concentrated energy, making it easier to form through cracks. Perforating bullets are arranged at multiple points in the pre-cracked holes, which causes less damage to the retained rock mass and makes the retained wall surface smoother.

[0024] (2) The energy of the perforating bullet is concentrated and the jet distance is long, which can reduce the number of pre-splitting holes, increase the spacing, and reduce the construction workload.

[0025] (3) Perforating bullets and perforating bullet racks are prefabricated products, which are conducive to centralized storage and management, and the on-site assembly is simple and convenient, which speeds up the engineering operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of blasthole arrangement for negative excavation of foundation pit in an embodiment of the present invention;

[0027] Figure 2 2 is a schematic structural diagram of a perforating charge rack according to an embodiment of the present invention;

[0028] Figure 3 is a top view of a perforating charge rack according to an embodiment of the present invention;

[0029] Figure 4 is a schematic diagram of a perforating charge installed on a perforating charge rack in an embodiment of the present invention;

[0030] Figure 5 Schematic diagram of jet generation by a perforating bullet in a pre-splitting hole in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings.

[0032] Attached Figures 1 to 5 The reference numerals in the figures are as follows:

[0033] 100, foundation pit area; 10, main blast hole area; 20, auxiliary hole area; 30, pre-crack hole area; 31, pre-crack hole; 311, blast hole; 312, groove; 40, slope rock mass; 50, perforating charge rack; 51, positioning block; 52, positioning hole; 521, large hole; 522, small hole; 523, deformation joint; 53, perforating charge; 530, jet; 531, small diameter end; 532, large diameter end; 533, positioning groove; 54, detonating line.

[0034] like Figure 1 As shown, for the blasting negative excavation of the foundation pit, the foundation pit area 100 is usually determined first, and then the main blasting hole area 10, the auxiliary hole area 20 and the pre-crack hole area 30 are arranged in sequence from the free surface of the step to the slope rock mass 40 in the foundation pit area 100. The main blasting holes in a plum blossom distribution are arranged in the main blasting hole area 10, the auxiliary holes in the auxiliary hole area 20 are arranged with a density slightly larger than that of the main blasting hole area 10, and the pre-crack hole area 30 is usually provided with linearly arranged pre-crack holes 31.

[0035] The present invention aims to provide a pre-splitting hole blasting structure which is conducive to fine control and has good effects on the quality of slope rock mass and the control of bedrock blasting vibration.

[0036] Combination Figure 2The negative excavation pre-splitting blasting charging structure of a channel foundation pit based on a distributed perforating charge combination provided in an embodiment of the present invention includes a perforating charge rack 50 and a perforating charge 53.

[0037] The perforating charge rack 50 is installed in the pre-crack hole 31, and a plurality of positioning holes 52 are arranged at intervals along the height direction on the perforating charge rack 50. In this embodiment, the spacing D between two adjacent positioning holes 52 is 40 to 60 cm. There are multiple pre-crack holes 31, which are arranged along a predetermined trajectory. It can be understood by those skilled in the art that, according to the design direction of the foundation pit, the arrangement trajectory of the plurality of pre-crack holes 31 can be linear, curved or annular. In this embodiment, the depth of the pre-crack hole 31 is 3 to 5 m, and the spacing between adjacent pre-crack holes 31 is 1 to 1.2 m.

[0038] The perforating bullet 53 is loaded in the positioning hole 52. The perforating bullet 53 includes a shell, a charge liner, a main explosive loaded between the shell and the charge liner, and a detonating charge at the rear end of the shell. The main explosive is a high-detonation-velocity explosive with a detonation velocity of 6800 m / s.

[0039] On a perforating charge rack 50, the jet directions of multiple perforating charges 30 are alternately oriented toward the first side and the second side of the pre-splitting direction, and the pre-splitting direction is the direction of the line connecting every two adjacent pre-splitting holes 31. In this way, the present invention implements pre-splitting blasting on the rock surface through the point jet formed by the perforating charge 53. Compared with linear shaped energy blasting, the point jet formed by the perforating charge 53 has less damage to the rock wall, low blasting vibration, and can form a high-quality slope rock mass.

[0040] Combination Figure 3 The pre-crack hole 31 includes a blast hole 311 and two grooves 312. The two grooves 312 are arranged at the edge of the blast hole 311 and are in the pre-crack direction. In this embodiment, the depth of the groove 312 is 10±2 mm. After the drilling equipment drills the blast hole 311, a circular saw blade is used to carve the groove 312 on the inner wall of the blast hole 311 along the depth of the blast hole 311. The present invention is conducive to promoting the development direction of the crack during the blasting vibration and making the pre-crack surface smoother.

[0041] The groove 312 can be set as a V-shaped groove or a rectangular groove. When set as a V-shaped groove, the angle of the groove 312 is 30° to 60°. The V-shaped groove is more conducive to the splitting of the rock and controls the extension direction of the crack. Under the influence of blasting and jet action, it is conducive to forming a flat pre-splitting surface.

[0042] Combination Figure 2 and Figure 3The perforating charge holder 50 is set to be cylindrical, and the diameter of the perforating charge holder 50 is smaller than the diameter of the inscribed circle of the pre-crack hole 31. The outer wall of the perforating charge holder 50 is provided with a positioning block 51, and the positioning block 51 matches the shape of the groove 312, so that the perforating charge holder 50 is located in the central position of the pre-crack hole 31.

[0043] The direction of the positioning hole 52 is the same as that of the positioning block 51, and the positioning block 51 is arranged at the upper and lower ends of the perforating charge rack 50. In this way, the construction personnel can identify the jet direction of the perforating charge 53. At the same time, the positioning block 51 is fixed to the groove 312, which is conducive to the centering of the perforating charge rack 50. Compared with the current linear shaped charge blasting device, it is simpler to assemble, safer and more convenient to store, and easy to insert into the blast hole, and accurate in centering.

[0044] In this embodiment, the perforating charge holder 50 is made of a thin steel pipe or a PVC pipe.

[0045] In some embodiments, the perforating charge rack 50 may also be a multi-section structure. For example, the perforating charge rack 50 includes specifications of 2 m and 1 m in length. The perforating charge racks 50 of different lengths are combined according to the depth of the pre-splitting hole 31. The perforating charge racks 50 are connected by threads or pins.

[0046] Combination Figure 4 In order to facilitate the assembly of the perforating bullet 53, the positioning hole 52 includes a large hole 521 and a small hole 522. The perforating bullet 53 is conical. The small diameter end 531 of the perforating bullet 53 is arranged in the small hole 522, and the large diameter end 532 of the perforating bullet 53 is arranged in the large hole 521. The large diameter end 532 and the small diameter end 531 of the perforating bullet 53 have portions exposed outside the outline of the perforating bullet frame 50.

[0047] In some embodiments, the diameter of the large diameter end 532 is slightly larger than the diameter of the large hole 521, and a deformation slit 523 is provided on the periphery of the large hole 521, and a positioning groove 533 is provided on the large diameter end 532 of the perforating bullet 53. Thus, when the perforating bullet 53 is assembled into the positioning hole 52, after the large diameter end 532 is inserted, the deformation slit 523 on the outside of the large hole 521 undergoes elastic deformation, and the positioning groove 533 is inserted into the inner wall of the large hole 521, thereby fixing the perforating bullet 53 to the perforating bullet holder 50.

[0048] In this embodiment, the deformation slit 523 is arc-shaped, and the arc length of the deformation slit 523 is π / 3. In this way, the deformation amount of the deformation slit 523 and the clamping strength of the perforating charge 53 can be reasonably determined, and when the perforating charge holder 50 is arranged in the pre-crack hole 31, the perforating charge 53 will not be deflected.

[0049] The perforating bullets 53 are stored separately, and the perforating bullet rack 50 is also stored separately. Before blasting, the perforating bullets 53 are installed in the positioning holes 52 in an orderly manner, and the upper and lower adjacent perforating bullets 53 are kept facing opposite directions and installed alternately until the installation is completed.

[0050] Combination Figure 4 A detonating wire 54 is arranged at the detonating charge of each perforating bullet 53, and the detonating wire 54 passes through the tube of the perforating bullet rack 50 to prevent the detonating wire 54 from breaking when the perforating bullet rack 50 is placed. The blasting of the perforating bullet 53 can be controlled by synchronous detonation or delayed detonation. In delayed detonation, the detonation is sequentially performed from the upper part to the lower part, and the delay interval is 50ms.

[0051] like Figure 5 As shown, in two adjacent pre-crack holes 31, the jet directions of the perforating bullets 30 at the same height are opposite. In this way, the jet 530 formed by each perforating bullet 53 forms a grid-like crack between adjacent pre-crack holes 31. Since the blasting is carried out from the main blasting area 10 and the auxiliary hole area 20 to the pre-crack hole area 30 during the negative excavation blasting of the foundation pit, the vibration energy of the perforating bullet 53 during the blasting shakes the rock off the formed cracks to form a smooth pre-crack surface. This point-shaped concentrated energy jet method can form a smoother pre-crack surface and reduce the amount of secondary construction on the slope rock mass in the later stage.

Claims

1. A channel foundation pit negative excavation pre-splitting blasting charging structure based on a distributed perforating bullet combination, characterized in that: include: A perforating bullet rack (50) is installed in the pre-splitting hole (31), and a plurality of positioning holes (52) are arranged at intervals along the height direction on the perforating bullet rack (50), and the spacing between two adjacent positioning holes (52) is 40 to 60 cm; the number of pre-splitting holes (31) is multiple, and they are arranged along a predetermined trajectory, and the spacing between adjacent pre-splitting holes (31) is 1 to 1.2 m; A perforating bullet (53) is loaded into the positioning hole (52); Wherein, on a perforating charge rack (50), the jet directions of a plurality of perforating charges (30) are alternately oriented toward a first side and a second side of a pre-splitting direction, wherein the pre-splitting direction is the direction of a line connecting every two adjacent pre-splitting holes (31); In two adjacent pre-splitting holes (31), the perforating bullets (30) at the same height have opposite jet directions.

2. The negative excavation pre-splitting blasting charging structure for waterway foundation pit based on the distributed perforating bullet combination according to claim 1 is characterized in that: The perforating charge rack (50) is of an integral or multi-section structure. When it is of a multi-section structure, perforating charge racks (50) of different lengths are combined and connected according to the depth of the pre-split hole (31).

3. The negative excavation pre-splitting blasting charging structure for waterway foundation pit based on the distributed perforating bullet combination according to claim 1 is characterized in that: The pre-splitting hole (31) comprises a blast hole (311) and two grooves (312), wherein the two grooves (312) are arranged at the edge of the blast hole (311) and are located in the pre-splitting direction; the perforating charge holder (50) is arranged in a cylindrical shape, wherein the diameter of the perforating charge holder (50) is smaller than the diameter of the inscribed circle of the pre-splitting hole (31), and a positioning block (51) is arranged on the outer wall of the perforating charge holder (50), wherein the shape of the positioning block (51) matches that of the grooves (312), so that the perforating charge holder (50) is located in the center of the pre-splitting hole (31).

4. The negative excavation pre-splitting blasting charging structure for waterway foundation pit based on the distributed perforating bullet combination according to claim 3 is characterized in that: The direction of the positioning hole (52) is the same as the direction of the positioning block (51), and the positioning block (51) is arranged at the upper end and the lower end of the perforating charge holder (50).

5. The negative excavation pre-splitting blasting charging structure for waterway foundation pit based on the distributed perforating bullet combination according to claim 3 is characterized in that: The groove (312) is configured as a V-shaped groove or a rectangular groove. When configured as a V-shaped groove, the angle of the groove (312) is 30° to 60°.

6. The negative excavation pre-splitting blasting charging structure for waterway foundation pit based on the distributed perforating bullet combination according to claim 3 is characterized in that: The depth of the groove (312) is 10±2 mm.

7. The negative excavation pre-splitting blasting charging structure for a waterway foundation pit based on a distributed perforating bullet combination according to any one of claims 3 to 6, characterized in that: The positioning hole (52) includes a large hole (521) and a small hole (522); the perforating bullet (53) is tapered; the small diameter end (531) of the perforating bullet (53) is arranged in the small hole (522); the large diameter end (532) of the perforating bullet (53) is arranged in the large hole (521); and the large diameter end (532) and the small diameter end (531) of the perforating bullet (53) have portions exposed outside the contour of the perforating bullet frame (50).

8. The negative excavation pre-splitting blasting charging structure for waterway foundation pit based on the distributed perforating bullet combination according to claim 7 is characterized in that: A deformation slit (523) is provided on the periphery of the large hole (521), and a positioning groove (533) is provided on the large diameter end (532) of the perforating bullet (53); when the perforating bullet (53) is assembled into the positioning hole (52), the deformation slit (523) can be elastically deformed, and the positioning groove (533) is inserted into the inner wall of the large hole (521).

9. The negative excavation pre-splitting blasting charging structure for waterway foundation pit based on the distributed perforating bullet combination according to claim 8 is characterized in that: The deformation seam (523) is arc-shaped.

10. The negative excavation pre-splitting blasting charging structure for waterway foundation pit based on a distributed perforating bullet combination according to claim 1 is characterized in that: A detonating line (54) is arranged at the detonating charge of each perforating bullet (53), and the detonating line (54) passes through the inside of the perforating bullet rack (50) to prevent the detonating line (54) from breaking when the perforating bullet rack (50) is placed.

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