A blasting excavation method suitable for side wall heading post-hole construction

Abstract

The present application belongs to the technical field of tunnel blasting excavation, and particularly relates to a blasting excavation method suitable for side wall pilot hole post-tunnel construction, which comprises the following steps in sequence: drilling of peripheral light blasting holes, drilling of floor holes, drilling of main blasting holes, explosive charging of peripheral light blasting holes, explosive charging of floor holes, explosive charging of main blasting holes, warning detonation, danger removal, slag cleaning, and initial support construction, wherein the above steps are repeated to complete the whole tunnel blasting excavation construction. According to the method, the position of the main blasting hole is adjusted, the free surface of the post-tunnel is fully utilized, the influence of post-tunnel blasting construction on the middle partition wall is reduced, the number of post-tunnel blast holes is reduced, the unit consumption of post-tunnel blasting is reduced, the construction cost is saved, and the problem of damage to the temporary support of the middle partition wall in the traditional tunnel blasting design is solved.

Description

Technical Field

[0001] This invention belongs to the field of tunnel blasting excavation technology, and provides a blasting excavation method suitable for the construction of the side wall pilot tunnel, which makes full use of the open face of the rear tunnel, reduces the impact of the blasting construction of the rear tunnel on the central diaphragm, reduces the number of blast holes in the rear tunnel, reduces the blasting consumption of the rear tunnel, and saves construction costs. Background Technology

[0002] In construction projects, tunnel construction often employs full-face excavation, bench excavation, and sidewall pilot tunnel excavation techniques, depending on the strength of the surrounding rock and the cross-sectional structure of the tunnel. In recent years, due to the surge in traffic volume and the continuous increase in the number of lanes on highways and municipal roads, the cross-sectional structure of tunnels has gradually become larger, and the construction of three-lane and even four-lane tunnels has become increasingly common. To ensure construction safety, the sidewall pilot tunnel construction technique is often used to control the settlement of the tunnel arch after excavation and ensure construction safety. However, the excavation of the main tunnel after the sidewall pilot tunnel requires blasting excavation due to the high strength of the surrounding rock. This often results in the temporary support of the central partition wall being damaged and needing to be dismantled and re-supported, which increases construction costs, reduces construction efficiency, and increases the probability of settlement or even collapse of the arch of large-section tunnels.

[0003] Therefore, it is necessary to design a blasting excavation method that can both ensure that the central diaphragm is not damaged and solve the problem of blasting excavation of the subsequent tunnel. This method is suitable for the construction of the subsequent tunnel through the side wall pilot tunnel and makes full use of the open face of the subsequent tunnel face. While improving construction efficiency and reducing construction costs, it also avoids the impact of blasting excavation of the subsequent tunnel on the central diaphragm. This blasting excavation method has important promotion significance for the blasting excavation of large-section tunnels, especially four-lane large-section tunnels. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a blasting excavation method suitable for the construction of a pilot tunnel in the side wall, which makes full use of the free face of the rear tunnel, reduces the impact of the blasting construction of the rear tunnel on the central diaphragm, reduces the number of blast holes in the rear tunnel, reduces the blasting unit consumption of the rear tunnel, and saves construction costs.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a blasting excavation method suitable for construction of tunnels after sidewall pilot tunnels, comprising the following steps:

[0007] The first step is to drill the surrounding blasting holes. Pneumatic drills are used to drill the surrounding blasting holes at the working face of the rear tunnel. The blasting holes are drilled horizontally along the excavation outline of the rear tunnel.

[0008] The second step is drilling the bottom plate holes. A pneumatic drill is used to drill the bottom plate holes on the working face of the tunnel. The bottom plate holes are drilled horizontally along the ground level of the working face.

[0009] The third step is the drilling of the main blasting hole. The main blasting hole is drilled on the side of the temporary support wall in the rear tunnel using a pneumatic drill. The main blasting hole is set horizontally.

[0010] The fourth step is to load the explosives into the peripheral blast holes, which use an air-gap loading structure.

[0011] The fifth step is to load the explosives into the bottom plate holes, which adopt a continuous loading structure.

[0012] Step 6: Loading explosives into the main blast hole. The main blast hole adopts an air-gap charging structure.

[0013] Step 7, warning and detonation: Set up a warning zone according to the designated warning zone, and detonate after the warning zone is in place; the detonation sequence is to first detonate the main blast hole, then detonate the surrounding light blast holes, and finally detonate the bottom plate hole.

[0014] Step 8: After hazard removal and debris clearing, carry out initial support construction;

[0015] Step 9: Repeat steps 1 through 8 above to complete the entire tunnel blasting and excavation construction.

[0016] The beneficial effects of this invention are: by adjusting the position of the main blast hole, this invention makes full use of the open face of the subsequent tunnel, reduces the impact of the subsequent tunnel blasting construction on the central diaphragm, reduces the number of blast holes in the subsequent tunnel, reduces the unit consumption of blasting in the subsequent tunnel, saves construction costs, and solves the problem of damage to the temporary support of the central diaphragm caused by traditional tunnel blasting design.

[0017] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0019] Figure 1 This is a structural schematic diagram of the present invention viewed from the front.

[0020] Figure 2 This is a schematic diagram of the structure at the main blast hole of the present invention;

[0021] Attached reference numerals: 1. Peripheral blasting holes; 2. Bottom plate holes; 3. Main blasting holes. Detailed Implementation

[0022] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0023] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual photographs, and should not be construed as limiting this patent. To better illustrate the embodiments of the invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0024] like Figure 1-2 As shown, the present invention provides a blasting excavation method suitable for the construction of a pilot tunnel after a sidewall pilot tunnel, comprising the following steps:

[0025] The first step is to drill the peripheral blasting holes 1. The pneumatic drill is used to drill the peripheral blasting holes 1 at the working face of the rear tunnel. The blasting holes are drilled horizontally along the excavation outline of the rear tunnel.

[0026] The second step is to drill the bottom plate hole 2. The bottom plate hole 2 is drilled horizontally along the ground level of the working face of the tunnel using an air-powered drill.

[0027] The third step is the drilling of the main blast hole 3. The main blast hole 3 is drilled on the side of the temporary support of the partition wall in the rear tunnel using a pneumatic drill. The main blast hole 3 is set horizontally.

[0028] The fourth step is to load the explosives into the peripheral blast holes 1, which adopt an air-gap loading structure.

[0029] Fifth step, loading explosives into hole 2 of the bottom plate. Hole 2 of the bottom plate adopts a continuous loading structure.

[0030] Step 6: Loading explosives into main blast hole 3. Main blast hole 3 adopts an air-gap charging structure.

[0031] Step 7, warning and detonation: Set up a warning zone according to the designated warning zone, and detonate after the warning zone is in place; the detonation sequence is as follows: first detonate the main detonation hole 3, then detonate the surrounding light detonation holes 1, and finally detonate the bottom plate hole 2.

[0032] Step 8: After hazard removal and debris clearing, carry out initial support construction;

[0033] Step nine: Repeat steps one through eight above to complete the entire tunnel blasting excavation. In this embodiment, by adjusting the position of the main blast hole 3, the open face of the subsequent tunnel is fully utilized, reducing the impact of the subsequent tunnel blasting on the central diaphragm, reducing the number of blast holes in the subsequent tunnel, reducing the unit consumption of blasting in the subsequent tunnel, saving construction costs, and solving the problem of damage to the temporary support of the central diaphragm caused by traditional tunnel blasting design.

[0034] To ensure the rationality of the design of the number of peripheral blasting holes 1 and to achieve the blasting effect with the fewest possible number, in the above embodiment, preferably, the hole spacing of the peripheral blasting holes 1 in the first step is 0.45m and the hole depth of the peripheral blasting holes 1 is 3.0m.

[0035] To ensure the rationality of the design of the number of holes 2 in the base plate, and to achieve the blasting effect with the fewest possible number, in the above embodiment, preferably: the hole spacing of the holes 2 in the base plate in the second step is 1.0m, and the hole depth of the holes 2 in the base plate is 3.0m.

[0036] To ensure the rationality of the design of the number of main blasting holes 3 and to achieve the blasting effect with the fewest possible number, in the above embodiment, preferably: the hole spacing and row spacing of the main blasting holes 3 in the third step are both 1.0m, and the hole depth of the main blasting holes 3 is set according to the hole bottom distance from the outline of the subsequent tunnel by 0.5m.

[0037] To ensure the blasting effect, in the above embodiments, preferably, the light blasting hole in the seventh step is detonated with a detonating cord.

[0038] To reduce the amount of explosive charge in the main blast hole 3 and reduce the impact of blasting on the temporary support of the intermediate partition wall, in the above embodiment, preferably, the main blast hole 3 in the seventh step is detonated with a detonating cord.

[0039] To ensure the blasting effect, in the above embodiments, preferably, the bottom plate hole 2 in the seventh step is detonated using a digital electronic detonator.

[0040] To ensure blasting effect and reduce blasting unit consumption, in the above embodiments, preferably, in steps four to six, after the explosives are loaded into the peripheral light blasting holes 1, the holes are filled with stemming material; after the explosives are loaded into the bottom plate holes 2, the holes are filled with stemming material; and after the explosives are loaded into the main blasting holes 3, the holes are filled with stemming material.

[0041] In the above embodiments, the initial support construction after the hazard removal and slag removal operations are carried out using conventional operations. The detonation of each blast hole is carried out in the order described above after conventional network connection.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A blasting excavation method suitable for construction of tunnels after sidewall pilot tunnels, characterized in that: Includes the following steps, The first step is to drill the surrounding blasting holes. Pneumatic drills are used to drill the surrounding blasting holes at the working face of the rear tunnel. The blasting holes are drilled horizontally along the excavation outline of the rear tunnel. The second step is to drill the bottom plate holes. Use an air-powered drill to drill the bottom plate holes on the working face of the tunnel. Drill the bottom plate holes horizontally along the ground level of the working face. The third step is the drilling of the main blasting hole. The main blasting hole is drilled on the side of the temporary support wall in the rear tunnel using a pneumatic drill. The main blasting hole is set horizontally. The fourth step is to load the explosives into the peripheral blast holes, which use an air-gap loading structure. The fifth step is to load the explosives into the bottom plate holes, which adopt a continuous loading structure. Step 6: Loading explosives into the main blast hole. The main blast hole adopts an air-gap charging structure. Step 7: Warning and detonation. Set up a warning zone according to the designated area, and detonate the explosives after the warning zone is in place. The detonation sequence is as follows: first, detonate the main blasting hole; then, detonate the surrounding light blasting holes; and finally, detonate the bottom plate holes. Step 8: After hazard removal and debris clearing, carry out initial support construction; Step 9: Repeat steps 1 through 8 above to complete the entire tunnel blasting and excavation construction.

2. The blasting excavation method for construction of a pilot tunnel after a sidewall pilot tunnel, as described in claim 1, is characterized in that: The spacing between the peripheral light-explosion holes in the first step is 0.45m, and the depth of the peripheral light-explosion holes is 3.0m.

3. The blasting excavation method for construction of a pilot tunnel after a sidewall pilot tunnel, as described in claim 1, is characterized in that: In the second step, the hole spacing of the bottom plate holes is 1.0m, and the hole depth of the bottom plate holes is 3.0m.

4. The blasting excavation method for construction of a pilot tunnel after a sidewall pilot tunnel, as described in claim 1, is characterized in that: In the third step, the hole spacing and row spacing of the main blasting holes are both 1.0m, and the hole depth of the main blasting holes is set according to the bottom of the hole being 0.5m from the outline of the subsequent tunnel.

5. The blasting excavation method for construction of a pilot tunnel after a sidewall pilot tunnel, as described in claim 1, is characterized in that: The detonation hole in the seventh step is initiated by detonating cord.

6. The blasting excavation method for construction of a pilot tunnel after a sidewall pilot tunnel, as described in claim 1, is characterized in that: In the seventh step, the main blast hole is detonated using a detonating cord.

7. The blasting excavation method for construction of a pilot tunnel after a sidewall pilot tunnel, as described in claim 1, is characterized in that: The bottom plate hole in the seventh step is detonated using a digital electronic detonator.

8. The blasting excavation method for construction of a pilot tunnel after a sidewall pilot tunnel, as described in claim 1, is characterized in that: In steps four through six, after the explosives are loaded into the peripheral blast holes, the holes are filled with stemming putty; after the explosives are loaded into the bottom plate holes, the holes are filled with stemming putty; and after the explosives are loaded into the main blast holes, the holes are filled with stemming putty.

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