Blasting structure and blasting method for uniform-scattering pressure-maintaining uniform-cracking composite roof

Abstract

The invention relates to a uniform-scattering pressure-maintaining uniform-cracking composite roof blasting structure and blasting method, and belongs to the technical field of mining. The uniform-scattering pressure-maintaining uniform-cracking composite roof blasting structure comprises a plurality of groups of rock stratums, joint cutting holes and energy gathering pipe fittings which are hierarchically distributed from inside to outside; the plurality of groups of joint cutting holes are distributed at intervals and penetrate into a rock stratum, and each joint cutting hole comprises a pre-blasting area and a non-blasting area; the multiple sets of energy gathering pipe fittings are arranged in the pre-blasting area at intervals in the length direction of the energy gathering pipe fittings, and stemming is placed between every two adjacent sets of energy gathering pipe fittings. According to the method, the sensitivity difference of different lithology to the blasting effect is fully utilized, the joint cutting hole explosive loading amount is designed for all rock stratums, the energy absorption effect of soft rock stratification to explosive shock waves is weakened, the phenomenon that blasting gas of hard rock stratification escapes to the soft rock stratification is reduced, all pre-blasting areas have the independent post-blasting pressure maintaining process, and the blasting effect of the pre-blasting areas is improved. And the blasting effect is optimized.

Description

Technical Field

[0001] The invention relates to the technical field of mining, and in particular to a uniform dispersion, pressure-maintaining and uniform fracture composite roof blasting structure and a blasting method. Background Art

[0002] Roof cutting and pressure relief is the main method of roof weakening technology. The effect of roof cutting will directly determine the degree of gangue filling in the goaf and limit the movement space of the high-level rock beam structure, thereby affecting the stress transfer relationship of the overburden in the goaf. At present, the research on roof weakening usually focuses on the surrounding rock control mechanism and technology after assuming a good roof cutting effect, focusing on the single aspect of support of "support-unloading" coordinated control, and lacks the experience of in-depth research on pre-splitting blasting technology adapted to the roof structure from the aspect of pressure relief.

[0003] The composite roof has multiple lithology layers, and the thickness, mineral composition, wave impedance, bedding and degree of development of joints and fissures of each lithology layer often vary greatly, so each lithology layer shows different explosion crack expansion rules under blasting. However, the traditional blasting method charging is usually not matched with each rock layer, and it is difficult to carry out targeted blasting and top cutting and pressure relief according to the composite roof structure. Usually, pressure relief is carried out according to a single rough pre-splitting blasting parameter of large charge and small spacing of slit holes. After blasting, the slit holes are prone to uneven cracks and are difficult to penetrate, so the top cutting effect cannot be guaranteed.

[0004] In view of the above-mentioned technical phenomenon, the inventors proposed a uniform dispersion, pressure-maintaining and uniform fracture composite roof blasting structure, and a blasting method using the blasting structure, so as to optimize the roof cutting effect. Summary of the invention

[0005] The purpose of the present invention is to provide a uniformly dispersed pressure-maintaining and uniformly fractured composite roof blasting structure and a blasting method, so that the blasting structure can be stratified for each lithology layer respectively, solving the problem that the pre-fracture cutting hole is difficult to penetrate and the roof cutting effect is poor.

[0006] The present invention provides a uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure, which adopts the following technical scheme: A uniform dispersion, pressure-maintaining and uniform fracture composite roof blasting structure, comprising: Multiple groups of rock layers distributed in layers from inside to outside; Slit holes, wherein the slit holes are provided in a plurality of groups, the plurality of groups of slit holes are distributed at intervals and penetrate into the rock formation, and the slit holes include a pre-blasting area and a non-blasting area; Energy-gathering pipes, wherein the energy-gathering pipes are provided in a plurality of groups, and the plurality of groups of the energy-gathering pipes are arranged in a pre-blasting zone at intervals along their own length direction, and each group of the energy-gathering pipes is installed in a pre-blasting zone of a group of rock formations, and the space between each two adjacent groups of the energy-gathering pipes is filled with taphole mud.

[0007] Preferably, the energy-gathering tube comprises an energy-gathering tube body and a digital electronic detonator, the energy-gathering tube body is provided with a tubular cavity penetrating along its length direction, the circumferential side wall of the energy-gathering tube body is provided with a plurality of groups of penetrating energy-gathering holes, the plurality of groups of energy-gathering holes are spaced apart along the length direction of the energy-gathering tube body, the digital electronic detonator is arranged in the tubular cavity, and the tubular cavity is filled with explosives.

[0008] Preferably, an energy focusing cone is provided at one end of the digital electronic detonator in the length direction, and the energy focusing cone is in the shape of a hollow cone. The tip of the energy focusing cone faces the inside of the digital electronic detonator, the tip of the energy focusing cone is in a state of being away from the bottom of the slit hole, and the explosive is in a state of being close to the energy focusing cone.

[0009] Preferably, the energy-gathering tube body is provided with a limiting member, and one end of the digital electronic detonator away from the explosive abuts against the limiting member.

[0010] Preferably, the limiting member is U-shaped, and both ends of the limiting member are inserted into the energy gathering hole.

[0011] Preferably, the taphole mud is located at the junction of two adjacent rock formations.

[0012] Preferably, the non-blasting area is filled with mud.

[0013] Preferably, the digital electronic detonator is externally connected to a parallel box.

[0014] The present invention also provides a blasting method according to the above-mentioned uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure, comprising the following steps: S1. Drill and coring the tunnel roof to be pre-splitting blasted. The coring length is greater than 3 times the mining height. Take a number of rock samples and test the explosive mechanical parameters to obtain the rock mass quality classification; S2. Based on the principle of pre-splitting blasting to adjust the basic top movement state and weaken the surrounding rock stress of the roadway, the slot holes are designed and constructed, and the slot holes are drilled and spied on, and the lithology structure and fracture development characteristics of each group of rock formations are analyzed, each group of rock formations is divided into pre-blasting area and non-blasting area, and the length of the pre-blasting area of ​​each group of rock formations is determined; S3, according to the characteristics of each group of rock formations in step S2, determine the amount of pre-loaded explosives in the pre-blasting zone of each group of rock formations in step S2, load the explosives and digital electronic detonators into the energy-gathering tube body to form an energy-gathering tube, place the energy-gathering tube into the pre-blasting zone at the bottom of the slit hole, and then fill the pre-blasting zone with taphole mud, thereby completing the filling work of the pre-blasting zone of a group of rock formations; S4, repeat step S3 until the filling work of the pre-blasting area of ​​each group of rock formations is completed; S6, plug the cut holes and use a parallel box to connect the electronic digital detonator detonation network in parallel; S7. Evacuate underground workers to a safe location and detonate to complete the blasting and top cutting operation.

[0015] In summary, the present invention includes the following beneficial technical effects: 1. The blasting structure of the present invention includes layers and distributed rock formations, slit holes and energy-gathering pipes. The slit holes include pre-blasting areas and non-blasting areas, that is, each rock formation is provided with a pre-blasting area or a non-blasting area, and the energy-gathering pipes are arranged in the pre-blasting area at intervals along their own length direction, and each group of energy-gathering pipes is installed in the pre-blasting area of ​​one group of rock formations, and taphole mud is arranged between each two adjacent groups of energy-gathering pipes. The taphole mud plays a barrier role, so that the pre-blasting area of ​​each rock formation has an independent post-blasting pressure-maintaining process, reduces the phenomenon of explosion-generated gas escaping to the soft rock formation, improves the blasting effect of the hard rock formation, and thus prolongs the explosive action time of the blasting area of ​​each rock formation.

[0016] 2. A blasting method provided by the present invention fully considers the difference in sensitivity of each group of rock formations to blasting, and is divided into pre-blasting zones for different rock formations. According to the pre-blasting zones for different rock formations, and combined with the research on the blasting direction and the length of the cutting hole of the energy-gathering pipe, the amount of explosives for the pre-blasting zones of different rock formations is proposed, and cannon mud is filled to provide pressure-maintaining conditions for the pre-blasting zones of each rock formation, so as to isolate the pre-blasting zones of each rock formation, which not only reduces the amount of explosives used, but also optimizes the blasting and top cutting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a uniformly dispersed pressure-maintained and uniformly fractured composite roof blasting structure provided by an embodiment of the present invention; Figure 2 It is a schematic diagram of a partial cross-sectional structure of an energy-gathering pipe; Figure 3 It is a schematic diagram of the energy-gathering blasting direction of the energy-gathering pipe; Figure 4 It is a schematic diagram of the structure of a digital electronic detonator; Figure 5 It is a structural schematic diagram of a mining site in an embodiment of the present invention.

[0018] Explanation of the accompanying reference numerals: 1. rock layer; 2. slit hole; 21. pre-blasting area; 211. hard rock blasting area; 212. soft rock blasting area; 22. non-blasting area; 3. energy-gathering pipe; 31. energy-gathering pipe body; 311. tube cavity; 312. energy-gathering hole; 313. limiter; 32. digital electronic detonator; 321. energy-gathering cone; 33. explosive; 4. gun mud; 5. mud; 6. parallel box; 7. core drilling. DETAILED DESCRIPTION

[0019] The following is combined with Figure 1-5 The present invention is described in further detail.

[0020] The present invention provides a uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure, referring to Figure 1 and Figure 2 , including multiple groups of rock layers 1 distributed from inside to outside and multiple groups of slit holes 2 penetrating into the rock layers 1; wherein each group of rock layers 1 has different lithology, multiple groups of slit holes 2 are distributed at intervals in the rock layers 1, and the slit holes 2 are divided into a pre-blasting area 21 and a non-blasting area 22 according to the lithology of each group of rock layers 1; multiple groups of energy-gathering pipes 3 are arranged in the pre-blasting area 21 of the slit holes 2, and multiple groups of energy-gathering pipes 3 are arranged at intervals in the pre-blasting area 21 along their own length direction, and each group of energy-gathering pipes 3 is correspondingly installed in the pre-blasting area 21 of a group of rock layers 1, and taphole mud 4 is placed between each two adjacent groups of energy-gathering pipes 3, and the taphole mud 4 in this embodiment is located at the junction of two adjacent rock layers 1, and the non-blasting area 22 is filled with mud 5. The taphole mud 4 plays a role of blocking the pre-blasting areas 21 of the two adjacent groups of rock layers 1, thereby reducing the mutual interference phenomenon of the pre-blasting areas 21 of the two adjacent groups of rock layers 1 during blasting.

[0021] Reference Figure 2 and Figure 3 The energy-gathering tube 3 includes an energy-gathering tube body 31 and a digital electronic detonator 32. The energy-gathering tube body 31 is provided with a tube cavity 311 penetrating along its length direction, and the circumferential side wall of the energy-gathering tube body 31 is provided with a plurality of penetrating energy-gathering holes 312. The penetrating direction of the energy-gathering holes 312 is perpendicular to the length direction of the energy-gathering tube body 31. The plurality of energy-gathering holes 312 are evenly spaced along the length direction of the energy-gathering tube body 31. The digital electronic detonator 32 is installed in the tube cavity 311, and the tube cavity 311 is filled with explosives 33. During the blasting process, the energy-gathering blasting direction is consistent with the penetrating direction of the energy-gathering holes 312.

[0022] Reference Figure 2 and Figure 4 An energy-gathering cone 321 is provided at one end of the length direction of the digital electronic detonator 32. The energy-gathering cone 321 is in the shape of a hollow cone. The tip of the energy-gathering cone 321 is facing the inside of the digital electronic detonator 32. Figure 1 The tip of the energy-gathering cone 321 is away from the bottom of the slit hole 2, the explosive 33 is close to the energy-gathering cone 321, and the digital electronic detonator 32 is externally connected to the parallel box 6. During the blasting process, the detonation wave caused by the digital electronic detonator 32 compresses the energy-gathering cone 321, thereby forming a high-speed metal jet to detonate the explosive 33 and cause a transmission explosion effect.

[0023] Reference Figure 2The energy-gathering tube body 31 is provided with a limiting member 313. The limiting member 313 in this embodiment is U-shaped, that is, both ends of the limiting member 313 are inserted into the energy-gathering hole 312, thereby completing the fixation of the limiting member 313. One end of the digital electronic detonator 32 away from the explosive 33 abuts against the limiting member 313, and the limiting member 313 plays a role of limiting the digital electronic detonator 32.

[0024] The present invention also provides a method for installing and blasting a uniformly dispersed pressure-maintained and uniformly fractured composite roof blasting structure, referring to Figure 1-Figure 5 , including the following steps: S1, the mining height of the coal mine is 3.51m, the tunnel roof to be pre-splitting blasted is drilled and cored 7, the coring length is greater than 3 times the mining height, and the coring length in this embodiment is 12m, and rock samples of mudstone, sandy mudstone and fine sandstone are obtained, and the wave impedance, elastic modulus, compressive strength and explosive mechanical parameters of the rock samples are measured to classify the rock mass quality; S2. The slit holes 2 are designed and constructed based on the principle of pre-splitting blasting to adjust the basic top movement state and weaken the surrounding rock stress of the tunnel. In this embodiment, the position of the slit holes 2 is 800 mm from the side of the working face to the tunnel wall, the angle of the slit holes 2 is 15°, the depth of the slit holes 2 is 13.0 m, and the hole spacing between two adjacent groups of slit holes 2 is 1500 mm. The direct top mudstone does not have the ability to resist the explosion, and it is easy to be punched, resulting in partial collapse of the roof. For this reason, it is divided into a pre-blasting area 21 with a length of 9.0 m and a non-blasting area 22 with a length of 4.0 m. The pre-blasting area 21 in this embodiment is located in the fine sandstone layer and the sandy rock layer, and the non-blasting area 22 is the mudstone layer; S3, drilling and peering into the slit hole 2, analyzing the lithology and fissure development characteristics of each group of rock layers 1, the pre-blasting area 21 in this embodiment is divided into a hard rock blasting area 211 and a soft rock blasting area 212 distributed from the inside to the outside. In this embodiment, 3.46m from the bottom of the slit hole 2 is a fine sandstone layer, which is hard and has undeveloped stratification, namely, the hard rock blasting area 211, and the length of this hard rock blasting area 211 is 3.2m; 6.03m from the outside of the fine sandstone layer is a sandy rock layer, which is relatively hard and has developed stratification, namely, the soft rock blasting area 212, and the length of this soft rock blasting area 212 is 5.3m; S4, according to the blasting areas and lengths divided by S3, determine the charge amount of each blasting area. In this embodiment, the charge density of the hard rock blasting area 211 is 600g / m, and the required charge amount is 1.92kg; the charge density of the soft rock blasting area 212 is 233g / m, and the required charge amount is 1.25kg; S5, from the bottom of the slit hole 2, the explosive 33 and the digital electronic detonator 32 are loaded into the energy-gathering tube body 31 according to the charge amount determined in S4, the blasting energy-gathering direction of the energy-gathering tube 3 should be toward the advancing direction of the working face, the tip of the energy-gathering cone 321 arranged at the end of the digital electronic detonator 32 always points away from the bottom of the slit hole 2 to control the detonation direction, and a limiter 313 is inserted into the energy-gathering hole 312 of the energy-gathering tube body 31 to fix the explosive 33 and the digital electronic detonator 32, thereby forming the energy-gathering tube 3; the energy-gathering tube 3 is installed in the hard rock blasting area 211 located at the bottom of the slit hole 2, and then the gun mud 4 is filled in the hard rock blasting area 211, thereby completing the filling work of the hard rock blasting area 211; S6, repeat step S5 until the filling work of the soft rock blasting area 212 in this embodiment is completed; S7, fill the non-blasting area 22 with mud 5 to block the slit holes 2, and use the parallel box 6 to connect the digital electronic detonator 32 in parallel to initiate the blasting network; S8. Evacuate underground workers to a safe location and detonate to complete the blasting and top cutting operation.

[0025] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure, characterized in that: include, Multiple groups of rock layers distributed in layers from inside to outside (1); Slit holes (2), the slit holes (2) being provided in a plurality of groups, the plurality of groups of slit holes (2) being distributed at intervals and penetrating into the rock layer (1), the slit holes (2) comprising a pre-blasting area (21) and a non-blasting area (22); Energy-gathering pipe fittings (3), wherein the energy-gathering pipe fittings (3) are provided in a plurality of groups, and the plurality of groups of energy-gathering pipe fittings (3) are arranged in a pre-blasting zone (21) at intervals along their length direction, and each group of energy-gathering pipe fittings (3) is installed in a pre-blasting zone (21) of a group of rock formations (1), and taphole mud (4) is filled between each two adjacent groups of energy-gathering pipe fittings (3).

2. The uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure according to claim 1, characterized in that: The energy-gathering tube (3) comprises an energy-gathering tube body (31) and a digital electronic detonator (32); the energy-gathering tube body (31) is provided with a tube cavity (311) penetrating along the length direction of the energy-gathering tube body; a plurality of groups of penetrating energy-gathering holes (312) are provided on the circumferential side wall of the energy-gathering tube body (31); the plurality of groups of energy-gathering holes (312) are distributed at intervals along the length direction of the energy-gathering tube body (31); the digital electronic detonator (32) is arranged in the tube cavity (311); and the tube cavity (311) is filled with explosive (33).

3. A uniform dispersion pressure-maintaining and homogeneous fracture composite roof blasting structure according to claim 2, characterized in that: An energy-gathering cone (321) is provided at one end of the digital electronic detonator (32) in the length direction. The energy-gathering cone (321) is in the shape of a hollow cone. The tip of the energy-gathering cone (321) faces the inside of the digital electronic detonator (32). The tip of the energy-gathering cone (321) is in a state of being away from the bottom of the slit hole (2). The explosive (33) is in a state of being close to the energy-gathering cone (321).

4. The uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure according to claim 2, characterized in that: The energy-gathering tube body (31) is provided with a limiting member (313), and one end of the digital electronic detonator (32) away from the explosive (33) abuts against the limiting member (313).

5. The uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure according to claim 4, characterized in that: The limiting member (313) is U-shaped, and both ends of the limiting member (313) are in a state of being inserted into the energy gathering hole (312).

6. The uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure according to claim 1, characterized in that: The taphole mud (4) is located at the junction of two adjacent rock formations (1).

7. The uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure according to claim 1, characterized in that: The non-blasting area (22) is filled with mud (5).

8. The uniform dispersion pressure-maintaining and uniform fracture composite roof blasting structure according to claim 2, characterized in that: The digital electronic detonator (32) is externally connected to a parallel box (6).

9. A blasting method for a homogeneous dispersion, pressure-maintaining and homogeneous fracture composite roof blasting structure according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Drilling and coring (7) the tunnel roof to be pre-splitting blasted, with the coring length being greater than 3 times the mining height, taking a number of rock samples and testing the explosive mechanical parameters to obtain the rock mass quality classification; S2. Designing the slotted holes (2) based on the principle of pre-splitting blasting to adjust the basic top movement state and weaken the surrounding rock stress of the tunnel, constructing the slotted holes (2), and drilling and probing the slotted holes (2), analyzing the lithology structure and fracture development characteristics of each group of rock strata (1), dividing each group of rock strata (1) into a pre-blasting area (21) and a non-blasting area (22), and determining the length of the pre-blasting area (21) of each group of rock strata (1); S3, according to the characteristics of each group of rock formations (1) in step S2, the amount of pre-loaded explosives (33) in the pre-blasting area (21) of each group of rock formations (1) in step S2 is determined, the explosives (33) and the digital electronic detonator (32) are loaded into the energy-gathering tube body (31) to form an energy-gathering tube (3), the energy-gathering tube (3) is placed in the pre-blasting area (21) at the bottom of the slotted hole (2), and then the pre-blasting area (21) is filled with taphole mud (4), thereby completing the loading work of the pre-blasting area (21) of a group of rock formations (1); S4, repeating step S3 until the filling work of the pre-blasting area (21) of each group of rock formations (1) is completed; S6, plugging the slit hole (2), and using the parallel box (6) to connect in parallel the electronic digital detonator detonation network; S7. Evacuate underground workers to a safe location and detonate to complete the blasting and top cutting operation.

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