First smooth surface tunnel blasting excavation method under broken geological condition

Abstract

The invention discloses a blasting excavation method for a first smooth surface tunnel under a broken geological condition, which belongs to the technical field of tunnel construction and comprises the following steps: S1, slotting hole drilling, charging and detonating; s2, auxiliary holes are drilled, charged and detonated; s3, rock ballast is transported outwards; s4, the tunnel face is cleaned; s5, pointedly drilling smooth surface holes, slotting holes and auxiliary holes, charging and detonating at the same time to form a concave tunnel face; s6, the step S5 is repeated till tunnel blasting excavation is completed; according to the method, tunnel blasting excavation construction is achieved through the method that the slotting holes and the auxiliary holes are blasted firstly and then the smooth surface holes, the slotting holes and the auxiliary holes are blasted at the same time in a circulating mode, more rock mass thickness can be reserved in the next footage, the danger of roof collapse and collapse is reduced, and the method is suitable for tunnel construction under the complex geological conditions such as crushing and the like; and meanwhile, the position of the smooth surface hole can be adjusted according to the rock mass retaining condition, and the influence of geological structure fractures on the blasting quality is eliminated.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel construction, and particularly relates to a method for blasting and excavating a pre-smooth tunnel under broken geological conditions. Background Art

[0002] In the construction of modern transportation infrastructure, tunnel engineering plays a key role, which is an important means to break through terrain obstacles, optimize traffic layout and improve transportation efficiency.

[0003] Blasting excavation construction is a commonly used method in tunnel construction, which can efficiently break rocks and open up tunnel space. The current tunnel blasting excavation construction sequence is as shown in the appendix Figure 1 That is, the cut holes, auxiliary holes (broken holes) and smooth holes (peripheral holes) form a cycle. That is, the cut holes are blasted first to provide a free face (free face) for the auxiliary holes, and then the auxiliary holes are blasted to provide a free face for the smooth holes.

[0004] The above tunnel blasting excavation construction sequence has the following problems, as shown in the appendix Figure 2 That is, in the case of relatively broken geological conditions, after the auxiliary holes are blasted, the rock layers in front of the smooth holes are unevenly retained, resulting in overbreak and underbreak, and the free face of the smooth holes gets out of control. At this time, the smooth holes have been charged and cannot be adjusted, resulting in poor blasting excavation construction effect.

[0005] In view of this, a method for blasting and excavating a pre-smooth tunnel under broken geological conditions is designed to solve the above problems. Summary of the Invention

[0006] To solve the problems raised in the above background art, the present invention provides a method for blasting and excavating a pre-smooth tunnel under broken geological conditions, which has the characteristics of being applicable to tunnel construction under complex geological conditions including broken ones.

[0007] To achieve the above object, the present invention provides the following technical solution: A method for blasting and excavating a pre-smooth tunnel under broken geological conditions, comprising the following steps: S1: Drilling, charging and detonating the cut holes; S2: Drilling, charging and detonating the auxiliary holes; S3: Removing the stone slag generated during the blasting of the cut holes and the auxiliary holes; S4: Cleaning the face; S5: Based on the blasting conditions of the cut holes and the auxiliary holes, specifically drilling, charging and simultaneously detonating the smooth holes, the cut holes and the auxiliary holes to form a concave face; S6: Repeating the above step S5 until the tunnel blasting excavation is completed.

[0008] Further, in the step S1, the hole spacing, hole diameter and hole depth of the cut holes are determined according to the geological conditions and blasting design requirements. The hole spacing is preferably 0.1 - 0.2 m, the hole diameter is preferably 40 - 100 mm, and the hole depth is preferably 2 - 5 m.

[0009] Further, in the step S2, the hole spacing, hole diameter and hole depth of the auxiliary holes are determined according to the geological conditions and blasting design requirements. The hole spacing is preferably 210 - 252 mm, the hole diameter is preferably 40 - 42 mm, and the hole depth is preferably 2 - 3 m.

[0010] Further, the specific steps of the step S3 include: Planning the outward transportation route of the muck removal equipment based on the tunnel construction environment. Among them, when the muck removal equipment travels on the planned outward transportation route, it is necessary to ensure that the muck removal equipment does not contact the tunnel construction surface; The muck removal equipment transports muck based on the planned outward transportation route.

[0011] Further, in the step S4, the cleaning of the heading face includes debris cleaning, water accumulation drainage treatment, and uneven position trimming treatment.

[0012] Further, in the step S5, the hole spacing, hole diameter and hole depth of the cut holes are the same as those in the step S1.

[0013] Further, in the step S5, the hole spacing, hole diameter and hole depth of the auxiliary holes are the same as those in the step S2.

[0014] Further, the hole spacing, hole diameter and hole depth of the smooth holes are determined according to the geological conditions and blasting design requirements. The hole spacing is preferably 500 - 800 mm, the hole diameter is preferably 40 - 50 mm, and the hole depth is preferably 2.2 - 3.2 m.

[0015] Further, in the step S5, the charge structure of the smooth holes is a detonating cord network.

[0016] Further, in the step S5, the concave heading face is a heading face with smooth holes on the outside, cut holes and auxiliary holes on the inside, and high around and low in the middle.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention realizes the tunnel blasting excavation construction by the method of first blasting the cut holes and auxiliary holes, and then cyclically blasting the smooth holes, cut holes and auxiliary holes simultaneously. This method can retain more rock mass thickness in the next footage, reduce the risks of roof fall and collapse, and is applicable to tunnel construction in complex geological conditions including fragmentation.

[0018] 2. The present invention can adjust the position of the smooth holes according to the situation of the reserved rock mass, eliminating the influence of geological structural fissures on the blasting quality.

[0019] 3. The smooth holes are located outside the cut holes and the auxiliary holes in space and are detonated first in time. There is no need to worry that the blasting of the cut holes and the auxiliary holes will damage the detonation network of the smooth holes. Therefore, the detonating cord network can be directly used without installing detonators in each hole, reducing the blasting material cost by 20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the construction sequence of the existing tunnel blasting excavation of the present invention; Figure 2 It is a schematic diagram of the problems encountered in the construction sequence of the existing tunnel blasting excavation of the present invention; Figure 3 It is a schematic diagram of the construction sequence of the tunnel blasting excavation of the present invention; Figure 4 It is a schematic diagram of the construction sequence of the tunnel blasting excavation of the present invention when encountering the same problems; Figure 5 It is a schematic diagram of the network relationship between the smooth holes in the existing and the tunnel blasting excavation of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] The present invention provides the following technical solutions: As shown in the attached Figure 3 figures, a method for smooth surface tunnel blasting excavation under broken geological conditions includes the following steps: S1: Drilling, charging and detonating the cut holes; S2: Drilling, charging and detonating the auxiliary holes; S3: Removing the rock slag generated during the blasting of the cut holes and the auxiliary holes; S4: Cleaning the face; S5: Based on the blasting conditions of the cut holes and the auxiliary holes, drilling, charging and simultaneously detonating the smooth holes, the cut holes and the auxiliary holes in a targeted manner to form a concave face; S6: Repeat the above step S5 until the tunnel blasting excavation is completed.

[0023] Specifically, in step S1, the hole spacing, hole diameter, and hole depth of the cut holes are determined according to geological conditions and blasting design requirements. The hole spacing is preferably 0.1 - 0.2 m, the hole diameter is preferably 40 - 100 mm, and the hole depth is preferably 2 - 5 m.

[0024] Specifically, in step S2, the hole spacing, hole diameter, and hole depth of the auxiliary holes are determined according to geological conditions and blasting design requirements. The hole spacing is preferably 210 - 252 mm, the hole diameter is preferably 40 - 42 mm, and the hole depth is preferably 2 - 3 m.

[0025] Specifically, the specific steps of step S3 include: Based on the tunnel construction environment, plan the external transportation route of the muck removal equipment. Among them, when the muck removal equipment travels on the planned external transportation route, it is necessary to ensure that the muck removal equipment does not contact the tunnel construction surface; The muck removal equipment transports muck based on the planned external transportation route.

[0026] Specifically, in step S4, the cleaning of the heading face includes debris cleaning, water accumulation drainage, and trimming of uneven positions.

[0027] Specifically, in step S5, the hole spacing, hole diameter, and hole depth of the cut holes are the same as those in step S1.

[0028] Specifically, in step S5, the hole spacing, hole diameter, and hole depth of the auxiliary holes are the same as those in step S2.

[0029] Specifically, the hole spacing, hole diameter, and hole depth of the smooth holes are determined according to geological conditions and blasting design requirements. The hole spacing is preferably 500 - 800 mm, the hole diameter is preferably 40 - 50 mm, and the hole depth is preferably 2.2 - 3.2 m.

[0030] Specifically, in step S5, the charge structure of the smooth holes is a detonating cord network.

[0031] Specifically, in step S5, the concave heading face is a heading face with smooth holes on the outside, cut holes and auxiliary holes on the inside, and high around and low in the middle.

[0032] When this application encounters problems in the existing tunnel blasting excavation construction sequence, as shown in the appendix Figure 4 As shown, this application adjusts the existing tunnel blasting excavation construction sequence, that is, simultaneously detonates the cut holes, auxiliary holes, and smooth holes. Since the smooth holes are located outside the cut holes and auxiliary holes in space, they are detonated first in time, that is, the smooth holes are detonated first, and the cut holes and auxiliary holes for the next footage are detonated subsequently. After blasting, more rock mass thickness is retained for the next footage, reducing the risks of roof fall and collapse. Especially in tunnel construction with complex geological conditions including fragmentation, etc., at the same time, the position of the smooth holes can be adjusted according to the retained rock mass situation to eliminate the influence of geological structure fissures on the blasting quality.

[0033] In the existing construction sequence of tunnel blasting excavation, the cut holes, auxiliary holes and smooth blasting holes are on the same plane, as shown in the appendix Figure 5 shown, and the smooth blasting holes are detonated later. Therefore, when the cut holes and auxiliary holes are detonated, the flying stones and shock waves generated by the blasting will damage the exposed smooth blasting hole network. Therefore, during the existing tunnel blasting excavation construction process, one detonator must be installed in each smooth blasting hole to ensure that the detonation signal has been transmitted into the hole before the cut holes are detonated and is not affected by the damage of the external network. In this application, the smooth blasting holes are outside the cut holes and auxiliary holes, and the detonation sequence is prior, and its detonation network will not be affected by the blasting of the cut holes and auxiliary holes. Therefore, a detonating cord network can be used, and one detonator can be saved for each blast hole, and 20% of the blasting material cost can be saved for each blasting.

[0034] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for blasting and excavating a smooth surface tunnel under broken geological conditions, characterized in that: The following steps are involved: S1: Drilling the slot hole, charging and detonating; S2: auxiliary hole drilling, charging and detonation; S3: slag produced during the blasting of the slot holes and auxiliary holes; S4: Clean the tunnel face; S5: Based on the blasting conditions of the slot holes and auxiliary holes, the smooth holes, slot holes and auxiliary holes are drilled, charged and detonated simultaneously to form a concave tunnel face; S6: Repeat the above step S5 until the tunnel blasting excavation is completed.

2. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 1, characterized in that: In step S1, the hole spacing, hole diameter and hole depth of the slot drilling are determined according to geological conditions and blasting design requirements. The hole spacing is preferably 0.1-0.2m, the hole diameter is preferably 40-100mm, and the hole depth is preferably 2-5m.

3. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 1, characterized in that: In step S2, the hole spacing, hole diameter and hole depth of the auxiliary hole drilling are determined according to geological conditions and blasting design requirements. The hole spacing is preferably 210-252 mm, the hole diameter is preferably 40-42 mm, and the hole depth is preferably 2-3 m.

4. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 1, characterized in that: The specific steps of step S3 include: The transportation route of the slag transport equipment is planned based on the tunnel construction environment. When the slag transport equipment is traveling on the planned transportation route, it must be ensured that the slag transport equipment does not touch the tunnel construction surface; The slag transportation equipment transports slag based on the planned transportation routes.

5. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 1, characterized in that: In step S4, the cleaning of the tunnel face includes cleaning of debris, drainage of accumulated water, and finishing of uneven locations.

6. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 2, characterized in that: In step S5, the hole spacing, hole diameter and hole depth of the slot holes are the same as those in step S1.

7. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 3, characterized in that: In step S5, the hole spacing, hole diameter and hole depth of the auxiliary holes are the same as those in step S2.

8. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 1, characterized in that: The hole spacing, hole diameter and hole depth of the smooth hole drilling are determined according to geological conditions and blasting design requirements. The hole spacing is preferably 500-800 mm, the hole diameter is preferably 40-50 mm, and the hole depth is preferably 2.2-3.2 m.

9. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 1, characterized in that: In step S5, the charge structure of the smooth surface is a detonating cord network.

10. The method for blasting and excavating a smooth-surface tunnel under broken geological conditions according to claim 1, characterized in that: In step S5, the concave tunnel face is a tunnel face with smooth holes on the outside, cut holes and auxiliary holes on the inside, and high around and low in the middle.

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