Hard rock tunnel electronic detonator ordered millisecond synergistic micro-vibration slotting structure

Abstract

The utility model discloses a hard rock tunnel electronic detonator ordered millisecond synergistic micro-vibration slotting structure, which is characterized in that through slotting hole design, the detonation sequence must be orderly detonated according to the design when a single hole is continuously detonated, and millisecond detonation intervals between adjacent slotting holes are equal; the time difference between the detonating time t1 of the first slotting hole and the detonating time tn of the last slotting hole must be smaller than t, the blasting effect of the hard rock tunnel can be greatly improved, rocks in the slot cavities are completely thrown out after blasting, and the blasting vibration influence is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic detonator blasting construction of hard rock tunnels, which is a micro-vibration slotting blasting technology. Background Art

[0002] Electronic detonators are detonators that use integrated circuits to replace the delay charge of electric detonators or detonating cord detonators to achieve delay. Figure 1 shown.

[0003] The detonator uses microelectronics technology, digital technology, and encryption technology to achieve functions such as delay, communication, and control. Its advantages are: the delay can be accurate to 1ms, the error is 0.1-0.5ms within 100ms, and the error is 0.1-0.5% when it is greater than 100ms, and the detonation time can be set arbitrarily according to the needs of the site. The minimum delay error of electric detonators or detonating cord detonators is 12.5ms and the maximum is 150ms. Based on the advantages of electronic detonators, they were initially mainly used in tunnel blasting in urban areas to reduce blasting vibrations, ensure building safety, and reduce the impact on residents' lives.

[0004] When the drilling and blasting method is used to construct tunnels in complex urban environments, large blasting vibrations are generated when electric detonators or detonating cord detonators are used for blasting, causing damage to nearby buildings and seriously interfering with the lives of nearby residents. The use of tunnel electronic detonator micro-vibration blasting technology, that is, tunnel electronic detonator single-hole continuous detonation technology, can reduce the blasting vibration speed to a minimum, thereby ensuring the safety of nearby buildings and the lives of nearby residents are not affected.

[0005] At present, mountain hard rock tunnels have begun to use electronic detonators for blasting construction. When using the experience of electronic detonators for micro-vibration blasting in urban tunnels, due to the hard surrounding rock of mountain tunnels, when micro-vibration blasting is used for slot holes, the rock in the slot cavity cannot be completely thrown out, and usually many deep residual holes are left, which seriously affects the blasting footage. Therefore, it is generally believed that hard rock tunnels cannot be constructed by micro-vibration blasting. Therefore, the blasting experience and concept of tunnel detonating cord detonators are used to set electronic detonators into 1 section, 3 sections, 5 sections, etc. for blasting construction. This blasting method does not take advantage of the advantages of electronic thunder, and the vibration generated by the blasting is very large, which poses a great threat to the stability of the initial spraying concrete behind the face and the safety of the secondary lining.

[0006] At present, tunnel electronic detonator blasting is being promoted in mountain hard rock tunnels. The success of tunnel electronic detonator micro-vibration blasting depends on slot hole blasting. Since the slot hole has only one free surface, the clamping effect is very large. The slot hole micro-difference blasting can completely throw out the rock in the slot cavity, creating a new free surface for other blast holes. Under the condition of two free surfaces, the clamping effect of other blast holes becomes smaller, and the strength of the rock will also be smaller because it has one more free surface than the slot cavity rock. Micro-difference blasting is easy to succeed, so that the entire tunnel electronic detonator micro-difference blasting can achieve the designed blasting effect. Utility Model Content

[0007] In view of this, the utility model provides a hard rock tunnel electronic detonator orderly micro-difference coordinated micro-vibration slotting structure, which can greatly improve the blasting effect of the hard rock tunnel. After the blasting, the rock in the slot cavity is completely ejected and the impact of the blasting vibration is greatly reduced.

[0008] The process of forming a free surface by blasting can be divided into three stages: the first stage is the propagation of stress waves from the center of the explosive package to the free surface; the second stage forms the contour line of the long projectile; the third stage forms a crack with a width of 8 to 10 mm, and finally forms an open surface. The time t for forming a new free surface is composed of three times, as shown in formula (1):

[0009] t=t1+t2+t3 (1)

[0010] t1 is the time required for the rock to reach a tensile fracture state after the charge explodes, as shown in formula (2):

[0011] t1=2w / cp (2)

[0012] Where: w is the resistance line, c p is the longitudinal wave propagation speed;

[0013] t2 is the time from the generation of the crack until the outline of the projectile is drawn on the crack surface. t2 can be obtained from formula (3):

[0014]

[0015] Where: u tr is the crack propagation velocity in a uniform medium at a certain unit consumption, κ is the fracture capacity coefficient of the medium, and β1 is the angle of the prismatic projectile;

[0016] t3 is the time required for the cracks surrounding the prismatic projectile to expand to the width corresponding to the new free surface formed. It is calculated based on the time required for the projectile to produce a displacement of 10 cm as follows:

[0017]

[0018] Where Φ is the diameter of the blasthole, ρ is the density of the rock, s is the area of ​​the projectile, S = w2 ρtan(β / 2).

[0019] The time of free surface formation is the key. The free surface formation process and time are: the radial compression stage of shock wave after the explosion of explosives; the stage of rock flakes falling at the free surface caused by stress wave reflection; the stage of explosion gas expansion, the initial radial cracks of rock rapidly expand under the dual effects of tensile stress and gas wedge, and the rock is thrown out. In the radial compression stage of shock wave, radial cracks and annular cracks are generated, and it takes 1 to 2 ms for radial cracks to appear; the stage of rock flakes falling caused by stress wave reflection on the free surface, which takes 10 to 20 ms.

[0020] A high-speed digital camera system is used to obtain complete images of rock detonation, cracking and throwing at the tunnel blasting site. The rock starts to move 15 to 18 ms after the explosives are detonated, forms a cavity around 21 ms, and then continues to expand before the rock is thrown out.

[0021] Based on the above content, the technical solution of the utility model is formed:

[0022] An ordered micro-difference coordinated micro-vibration slotting structure for electronic detonators in hard rock tunnels, wherein slotting holes are arranged vertically and linearly on both sides of the tunnel centerline, and an ordered micro-difference delay structure is adopted. The slotting holes start from the bottom slotting holes, and the bottom row of slotting holes is t1, t2 from left to right; the second row is t3, t4, ..., from left to right, until the top row, from left to right is tn-1, tn; the delay intervals between the slotting holes are equal and set to Δt, the detonation time of the first slotting hole is t1=0ms, the detonation time of the second hole is t2=t1+Δt, t3=t2+Δt, and so on, tn≤t, wherein t is the time for the explosive to form a free surface after being buried in the rock at a certain depth and exploded; the time t for forming a new free surface is composed of three times, as shown in formula (1):

[0023] t=t1+t2+t3 (1)

[0024] t1 is the time required for the rock to reach a tensile fracture state after the charge explodes, as shown in formula (2):

[0025] t1=2w / c p (2)

[0026] Where: w is the resistance line, c p is the longitudinal wave propagation speed;

[0027] t2 is the time from the generation of the crack until the outline of the projectile is drawn on the crack surface. t2 can be obtained from formula (3):

[0028]

[0029] Where: u tris the crack propagation velocity in a uniform medium at a certain unit consumption, κ is the fracture capacity coefficient of the medium, and β1 is the angle of the prismatic projectile;

[0030] t3 is the time required for the cracks surrounding the prismatic projectile to expand to the width corresponding to the new free surface formed. It is calculated based on the time required for the projectile to produce a displacement of 10 cm as follows:

[0031]

[0032] Where Φ is the diameter of the blasthole, ρ is the density of the rock, s is the area of ​​the projectile, S = w 2 ρtan(β / 2)

[0033] Furthermore, the total number of the slot holes is 20, and t=20ms.

[0034] Furthermore, the delay error of the electronic detonator is 0.1-0.5 ms within 100 ms, and is 0.1-0.5% when it is greater than 100 ms, and the detonation time can be set arbitrarily according to the needs of the site.

[0035] Furthermore, it also includes setting up a vibration sensor to monitor the blasting vibration.

[0036] The utility model has the following technical effects:

[0037] The utility model improves the blasting effect of hard rock tunnels through an orderly, equally spaced and coordinated arrangement structure. Orderly, that is, the detonation sequence of the slot holes must be detonated in an orderly manner according to the design when the single slot holes are detonated continuously; equally spaced, that is, the micro-difference intervals Δt between adjacent slot holes are equal; coordinated, that is, the time difference between the detonation time t1 of the first slot hole and the detonation time tn of the last slot hole must be less than t, that is, starting from the bottom slot hole, from left to right, from bottom to top, one by one, the cracks generated by the first blast hole reduce the strength of the rock around the subsequent detonation holes, reduce the clamping effect, and can reduce the blasting vibration generated. It is necessary to ensure that the rock in the slot area is not thrown out when the last slot hole is detonated, that is, tn≤t, so that the total amount of explosives in all slot holes is orderly released and resonates during the period of t1 to tn, and the rock in the slot area is completely thrown out. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the structure of an electronic detonator.

[0039] Figure 2 This is a schematic diagram of the blasthole arrangement in a hard rock tunnel.

[0040] Figure 3 It is the vibration waveform when the slot holes are detonated simultaneously.

[0041] Figure 4 It is the vibration waveform when the delay interval of the slot hole is 1ms.

[0042] Figure 5 This is a schematic diagram of the arrangement of slot holes in a hard rock tunnel.

[0043] Figure 6 It is a schematic diagram of the projectile of single-hole blasting. DETAILED DESCRIPTION

[0044] The present invention is described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0045] An ordered micro-difference coordinated micro-vibration slotting structure for electronic detonators in hard rock tunnels, wherein slotting holes are arranged vertically and linearly on both sides of the tunnel centerline, and an ordered micro-difference delay structure is adopted. The slotting holes start from the bottom slotting holes, and the bottom row of slotting holes is t1, t2 from left to right; the second row is t3, t4, ..., from left to right, until the top row, from left to right is tn-1, tn; the delay intervals between the slotting holes are equal and set to Δt, the detonation time of the first slotting hole is t1=0ms, the detonation time of the second hole is t2=t1+Δt, t3=t2+Δt, and so on, tn≤t, wherein t is the time for the explosive to form a free surface after being buried in the rock at a certain depth and exploded; the time t for forming a new free surface is composed of three times, as shown in formula (1):

[0046] t=t1+t2+t3 (1)

[0047] t=t1+t2+t3 (1)

[0048] t1 is the time required for the rock to reach a tensile fracture state after the charge explodes, as shown in formula (2):

[0049] t1=2w / c p (2)

[0050] Where: w is the resistance line, c p is the longitudinal wave propagation speed;

[0051] t2 is the time from the generation of the crack until the outline of the projectile is drawn on the crack surface. In this embodiment, a projectile is considered to be cut into an elliptical shape by the blasthole, such as Figure 6 As shown, t2 can be obtained by formula (3)

[0052]

[0053] Where: u tris the crack propagation velocity in a uniform medium at a certain unit consumption, κ is the fracture capacity coefficient of the medium, and β1 is the angle of the prismatic projectile;

[0054] t3 is the time required for the cracks surrounding the prismatic projectile to expand to the width corresponding to the new free surface formed. It is calculated based on the time required for the projectile to produce a displacement of 10 cm as follows:

[0055]

[0056] Where Φ is the diameter of the blasthole, ρ is the density of the rock, s is the area of ​​the projectile, S = w 2 ρtan(β / 2)

[0057] Furthermore, the total number of the slot holes is 20, and t=20ms.

[0058] Furthermore, the delay error of the electronic detonator is 0.1-0.5 ms within 100 ms, and is 0.1-0.5% when it is greater than 100 ms, and the detonation time can be set arbitrarily according to the needs of the site.

[0059] Furthermore, it also includes setting up a vibration sensor to monitor the blasting vibration.

[0060] Field trials:

[0061] When a hard rock tunnel is excavated by blasting, 20 slot holes are cut. Figure 2 As shown in the figure, the delay interval between the slot holes is 3ms, and the total blasting time of 20 slot holes is 57ms. After the blasting, the rock in the slot cavity is not completely thrown out, leaving many residual holes with a length of 45cm to 90cm; when the delay interval of the slot holes is reduced to 2ms, the total blasting time of the 20 slot holes is 38ms, and some rocks in the slot cavity are still not completely thrown out after the blasting, and some residual holes with a length of 30cm to 40cm are still left; when the delay interval between the slot holes is reduced to 1ms, the total blasting time of the 20 slot holes is 19ms, and the rock in the slot cavity is completely thrown out after the blasting, and the vibration speed at the same distance behind the tunnel face is reduced from the vibration speed of 5.1cm / s generated by the simultaneous blasting of the original slot holes to the vibration speed of 1.4cm / s, as shown in the figure. Figure 3 and Figure 4 shown.

[0062] The principle of the orderly micro-difference coordinated micro-vibration trenching method of electronic detonators in hard rock tunnels is as follows:

[0063] As the surrounding rock of hard rock tunnels is very hard and the rock's compressive, tensile and shear strengths are very high, in order to form the designed slot cavity by micro-vibration blasting of the slot holes, all the slot holes must work in a coordinated manner, that is, all the slot holes must be blasted in an orderly and micro-differenced manner to completely eject the rock in the slot cavity.

[0064] Assume that the total number of slot holes in a hard rock tunnel is 20. Figure 5 As shown. The delay intervals between the slot holes are equal and set to Δt. The detonation time of the first slot hole is t1 = 0ms, the detonation time of the second hole is t2 = t1 + Δt, t3 = t2 + Δt, and so on. t20≤t, where t is the time it takes for the explosive to form a free surface after being buried in the rock at a certain depth and exploded. In general, t = 20ms.

[0065] Operation key: The grooving must be in orderly micro-differences, that is, starting from the bottom grooving hole, the bottom row from left to right is t1, t2; the second row from left to right is t3, t4, ..., until the top row, from left to right is t19, t20.

[0066] The principle of the slotting method of electronic detonators in hard rock tunnels with orderly micro-difference coordinated micro-vibration blasting: the first slot hole is t1, the second is t2, and the last is tn, where t is the time it takes for the explosives to form a free surface after being buried at a certain depth in the rock and exploded. Since the surrounding rock of hard rock tunnels is hard and has high compressive, tensile and shear strengths, the micro-vibration blasting of slot holes must completely remove the rock in the slot area to form a cavity. All slot holes must meet the following conditions: ① Orderly, when the slot holes are detonated continuously, the detonation sequence must be detonated in an orderly manner according to the design, t1 detonates first, then t2, and so on; ② The micro-difference intervals Δt between adjacent slot holes are equal, that is, the micro-difference detonation intervals between adjacent slot holes are equal; ③ Coordinated, the detonation time t1 of the first slot hole is the same as the detonation time t1 of the last slot hole. The time difference between the times tn must be less than t, that is, starting from the lowest slot hole, detonate one by one from left to right and from bottom to top. The cracks caused by the first blasting hole reduce the strength of the rock around the subsequent blasting holes, reduce the clamping effect, and reduce the blasting vibration. It is necessary to ensure that the rock in the slot area is not thrown out when the last slot hole is detonated, that is, tn≤t, so that the total amount of explosives in all slot holes is released in an orderly manner during the period of t1~tn to form resonance and completely throw out the rock in the slot area.

[0067] The above is only one of the embodiments of this patent, and does not limit this patent in other forms. Any technician familiar with this profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of this patent without departing from the content of the technical solution of this patent still falls within the protection scope of the technical solution of this patent.

Claims

1. A hard rock tunnel electronic detonator orderly micro-difference coordinated micro-vibration slotting structure, characterized in that: The slot holes are arranged vertically linearly along both sides of the tunnel centerline, and an ordered micro-difference delay structure is adopted. The slot holes start from the bottom slot hole. The bottom row of slot holes is t1, t2 from left to right; the second row is t3, t4, ..., from left to right, until the top row, from left to right is tn-1, tn; the delay intervals between the slot holes are equal and set to Δt. The detonation time of the first slot hole is t1 = 0ms, the detonation time of the second hole is t2 = t1 + Δt, t3 = t2 + Δt, and so on, tn ≤ t, where t is the time for the explosive to form a free surface after being buried in the rock at a certain depth and exploded; the time t for forming a new free surface is composed of three times, as shown in formula (1): t=t1+t2+t3 (1) t1 is the time required for the rock to reach a tensile fracture state after the charge explodes, as shown in formula (2): t1=2w / c p (2) Where: w is the resistance line, c p is the longitudinal wave propagation speed; t2 is the time from the generation of the crack until the outline of the projectile is drawn on the crack surface; Where: u tr is the crack propagation velocity in a uniform medium at a certain unit consumption, κ is the fracture capacity coefficient of the medium, and β1 is the angle of the prismatic projectile; t3 is the time required for the cracks surrounding the prismatic projectile to expand to the width corresponding to the new free surface formed. It is calculated based on the time required for the projectile to produce a displacement of 10 cm as follows: Where Φ is the diameter of the blasthole, ρ is the density of the rock, s is the area of ​​the projectile, S = w 2 ρtan(β / 2).

2. The hard rock tunnel electronic detonator ordered micro-difference coordinated micro-vibration slotting structure according to claim 1 is characterized in that: The total number of the cutout holes is 20, and t=20 ms.

3. The hard rock tunnel electronic detonator ordered micro-difference coordinated micro-vibration slotting structure according to claim 1 is characterized in that: The delay error of the electronic detonator is 0.1-0.5ms within 100ms, and 0.1-0.5% when it is greater than 100ms. The detonation time can be set arbitrarily according to on-site needs.

4. The hard rock tunnel electronic detonator ordered micro-difference coordinated micro-vibration slotting structure according to claim 1 is characterized in that: It also includes setting up vibration sensors to monitor blasting vibrations.

Images