Multi-stage slotting blasting method for passing different structure faults at underground working face of coal mine

Abstract

The present application belongs to the technical field of coal mine underground blasting, and is a multi-stage slotting blasting method for passing through different structure faults in underground working face, aiming to solve the problems of low utilization rate of blasting holes, high rate of large gangue and long gangue throwing in traditional coal mine underground working face passing through faults, meet the daily cycle footage of working face, and reduce construction cost and labor cost. The feature is to use the segmented millisecond blasting technology between slotting holes to realize the segmented expansion of slotting area, provide new free surface for the expansion slotting area and rock breaking area, use the segmented millisecond blasting technology in the expansion slotting hole and rock breaking hole to realize the deepening of blasting depth and the reduction of gangue size. The present application solves the problem of low utilization rate of explosives in working face passing through faults due to the clamping effect of single free surface of coal mine underground on rock mass, improves the blasting single cycle footage, and realizes the requirements of normal production of coal mine underground working face.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of underground coal mine blasting, and particularly relates to a multi-order slotting blasting method for passing different structure faults in a coal mine underground working face. BACKGROUND

[0002] Due to the complexity of coal seam occurrence conditions, various geological structures such as faults, collapse columns and intrusive rocks are often encountered in the process of underground coal mining working face advancing. These geological anomaly areas not only destroy the continuity of the coal seam, but also have a strength much greater than that of the coal seam, resulting in a rapid decline in the cutting efficiency of the fully mechanized machine, which seriously affects the normal production of the coal mine.

[0003] Because these geological anomaly areas cannot be completely avoided by working face arrangement, when passing through the fault, the fully mechanized working face generally adopts the methods of working face moving, detouring and blasting to assist the rock breaking of the coal mining machine. Moving or detouring the fault will cause production stoppage or a substantial reduction in production, consume a large amount of funds, and cause damage to the fully mechanized equipment. The method of combining shallow hole blasting with coal mining machine rock breaking also has certain shortcomings. On the one hand, the protection of equipment near the working face is difficult during blasting construction, and flying stones are easy to damage the working face facilities; on the other hand, the shallow hole blasting footage is generally between 1-1.6m, the utilization rate of the blast hole is low, the blasting volume is small, the cycle times of blasting and advancing are many, which makes the working face advancing and mining slow, not only disrupts the mining plan, but also has safety hazards such as spontaneous combustion of coal dust in the goaf and deformation and damage of the roof and floor. In order to improve the rock breaking efficiency, some scholars change the shallow hole blasting to deep hole blasting, which can increase the footage, but the charge quantity is large, the labor intensity of workers is large, the blasting shock wave is large, the damage to the surrounding rock is serious, and the working face mining progress is affected.

[0004] To achieve short blasting cycles, large advances per cycle, and high borehole utilization, and to address the clamping effect of a single free face on the rock mass underground, this invention draws upon methods of blasting excavation in rock tunnels (tunnels) and introduces slotting blasting. Slotting blasting is divided into straight-hole slotting blasting, oblique-hole slotting blasting, and mixed slotting blasting, each with its own advantages and disadvantages, and applicable conditions. Generally, shallow-hole blasting often uses oblique-hole slotting, while in medium-deep or deep-hole blasting, vertical slotting is more commonly used because the borehole depth of oblique-hole slotting is limited by the width of the tunnel cross-section. In slotting blasting, the selection of the slotting method, the borehole mesh parameters, the charge structure, the sequence of borehole detonation, and the filling length directly affect the slotting effect. The quality of the slotting effect largely determines the overall effect and speed of fault blasting. The location and charge amount of the slotting holes must be designed scientifically and rationally, and they should be placed in areas with weak surfaces as much as possible. Faults in coal mines generally have two types of rock strata structures: coal-bearing faults and whole-rock faults. Therefore, different cutting schemes should be designed according to the characteristics of the fault structure. A reasonable cutting hole layout can obtain a larger cutting area, providing new free surfaces for the expansion zone and rock-breaking zone. This is beneficial for improving the utilization rate of blast holes, making full use of explosive energy to break rocks, effectively reducing the proportion of large pieces of gangue, reducing the distance of gangue throwing, and preventing flying gangue from damaging equipment behind the working face.

[0005] In summary, there is an urgent need to invent a multi-stage slotting blasting method for underground coal mine working faces passing through faults with different structures, which can increase the slotting hole depth and drilling and blasting single-cycle advance while reducing the damage to the surrounding rock caused by fault rock mass blasting vibration, reducing shock waves, and reducing the rock dumping distance. Summary of the Invention

[0006] The purpose of this invention is to provide a multi-stage slotting blasting method for underground coal mine working faces encountering faults of different structures, so as to solve the above-mentioned problem of underground coal mine working faces encountering faults.

[0007] The technical solution of this invention is: a multi-stage slotting blasting method for underground coal mine working faces passing through faults of different structures, comprising the following steps:

[0008] Step 1: Take the fault 1-3 encountered in the underground working face 1-1 of the coal mine as the blasting area 1-6, measure the length of the blasting area 1-6 in the working face 1-1, determine the middle part of the length direction as the cutting area, and then determine the position and angle of the cutting hole according to the type of fault 1-3 and mark it. Then complete the drilling work of the cutting area.

[0009] Step 2: Determine the location of the trenching area, and then determine and mark the location and angle of the trenching holes. Determine the location of the rock-breaking area, then determine and mark the location and angle of the rock-breaking holes, and finally complete the drilling work in the trenching area and the rock-breaking area.

[0010] Step three, filling digital electronic detonator and explosive in the cut hole, completing the cut hole explosive filling, plugging, wiring and shooting work;

[0011] Step four, filling digital electronic detonator and explosive in the cut hole and rock breaking hole, completing the cut hole and rock breaking hole explosive filling, plugging, wiring and shooting work.

[0012] The underground structure stress causes the roof 1-4 and floor 1-5 of the coal seam 1-2 to be dislocated to form a fault 1-3, and the working face 1-1 in the underground coal mine encounters the fault 1-3 in the advancing process, since the area at the fault 1-3 is relatively high in hardness relative to the coal seam, it cannot pass directly by using the coal mining machine, and it is necessary to perform blasting weakening in the area so as to facilitate the passing of the coal mining machine, and the area needing blasting weakening is the to-be-blasted area 1-6.

[0013] Step one includes the following contents:

[0014] If the to-be-blasted area 1-6 contains a coal interlayer, and the thickness of the coal interlayer is greater than or equal to 40 cm, it is defined as a coal interlayer in the present application, and the coal interlayer in a range of 2 m in the middle of the to-be-blasted area 1-6 is taken as a cut hole area, and a row of five cut holes, namely coal interlayer cut holes, are arranged at equal intervals in the cut hole area, and they are in turn a coal interlayer first-order cut hole 2-1, a coal interlayer second-order cut hole 2-2, a coal interlayer third-order cut hole 2-3, a coal interlayer fourth-order cut hole 2-4, and a coal interlayer fifth-order cut hole 2-5, the hole diameter of each coal interlayer cut hole is 42 mm, the spacing between adjacent coal interlayer cut holes is 50 cm, the angle between each coal interlayer cut hole and the horizontal direction is 60°, the vertical depth of the coal interlayer first-order cut hole 2-1 is 2.8 m, and the vertical depths of the coal interlayer second-order cut hole 2-2, the coal interlayer third-order cut hole 2-3, the coal interlayer fourth-order cut hole 2-4, and the coal interlayer fifth-order cut hole 2-5 are 3.2 m.

[0015] If the to-be-blasted area 1-6 does not contain a coal interlayer or the thickness of the coal interlayer is less than 40 cm, it is defined as a full rock fault in the present application, and a range of 50 cm in the middle of the to-be-blasted area 1-6 is taken as a cut hole area, and eight cut holes, namely full rock fault cut holes, are arranged in four rows and two columns in the cut hole area, and the spacing and row spacing of the full rock fault cut holes are both 50 cm, and they are in turn a full rock fault first-order cut hole 3-1, a full rock fault second-order cut hole 3-2, a full rock fault third-order cut hole 3-3, and a full rock fault fourth-order cut hole 3-4 from the first row of cut holes to the fourth row of cut holes, the hole diameter of each full rock fault cut hole is 42 mm, the angle between each full rock fault cut hole and the vertical direction is 60°, the vertical depth of the full rock fault first-order cut hole 3-1 is 2.8 m, and the vertical depths of the full rock fault second-order cut hole 3-2, the full rock fault third-order cut hole 3-3, and the full rock fault fourth-order cut hole 3-4 are 3.2 m.

[0016] Step two includes the following contents:

[0017] If it is a coal seam fault, the coal seam slot hole is arranged at 80 cm above the coal seam slot hole and 80 cm below the coal seam slot hole. The slot hole, i.e. the coal seam fault slot hole 2-6, is two rows and three columns of six holes. The coal seam fault slot hole 2-6 is arranged in the center of the slot area. The distance between each row of coal seam fault slot holes 2-6 is 80 cm. Each coal seam fault slot hole 2-6 is perpendicular to the working face 1-1. The hole diameter of each coal seam fault slot hole 2-6 is 42 mm. The hole depth of each coal seam fault slot hole 2-6 is 3.2 m.

[0018] If it is a full rock fault, the two columns of full rock fault slot holes are opposite to the inside and opposite to the outside. The first column of full rock fault slot holes is 1 m outside and the second column of full rock fault slot holes is 1 m outside. The slot area is 1 m outside the first column of full rock fault slot holes and 1 m outside the second column of full rock fault slot holes. The slot hole, i.e. the full rock fault slot hole 3-5, is three rows and two columns of six holes. The full rock fault slot hole 3-5 is arranged in the center of the slot area. The distance between each column of full rock fault slot holes 3-5 is 1 m. Each full rock fault slot hole 3-5 is perpendicular to the working face 1-1. The hole diameter of each full rock fault slot hole 3-5 is 42 mm. The hole depth of each full rock fault slot hole 3-5 is 3.2 m.

[0019] Step two includes the following contents:

[0020] If it is a coal seam fault, the right side of the coal seam first-order slot hole 2-1 and the left side of the coal seam fifth-order slot hole 2-5 are the rock breaking area. One column of three coal seam fault first rock breaking holes 2-7 is arranged 1 m to the right of the coal seam first-order slot hole 2-1. One column of three coal seam fault second rock breaking holes 2-8 is arranged 1.2 m to the right of the coal seam fault first rock breaking hole 2-7 to the right of the coal seam first-order slot hole 2-1. One column of three coal seam fault third rock breaking holes is arranged 1.2 m to the right of the coal seam fault second rock breaking hole 2-8 to the right of the coal seam first-order slot hole 2-1. This is repeated until the edge of the area to be blasted. One column of three coal seam fault first rock breaking holes 2-7 is arranged 1 m to the left of the coal seam fifth-order slot hole 2-5. One column of three coal seam fault second rock breaking holes 2-8 is arranged 1.2 m to the left of the coal seam fault first rock breaking hole 2-7 to the left of the coal seam fifth-order slot hole 2-5. One column of three coal seam fault third rock breaking holes is arranged 1.2 m to the left of the coal seam fault second rock breaking hole 2-8 to the left of the coal seam fifth-order slot hole 2-5. This is repeated until the edge of the area to be blasted. The diameter of each rock breaking hole is 42 mm. The distance between each column of rock breaking holes is 1.0 m and the row distance is 1.2 m. Each rock breaking hole is perpendicular to the working face. The hole depth of each rock breaking hole is 3.2 m.

[0021] If it is full rock fault, full rock fault expansion slot hole 3-5 is outside the broken rock area, and full rock fault broken rock hole 3-6 is arranged every 1.2m with 3 broken rock holes outside full rock fault expansion slot hole 3-5 until the edge of the area to be blasted; the diameter of each broken rock hole is 42mm, and the middle distance of each row of broken rock holes is 1.0m. The row distance is 1.2m, and each broken rock hole is drilled perpendicular to the working face, and the hole depth of each broken rock hole is 3.2m.

[0022] The third step includes the following contents:

[0023] If it is full rock fault, full rock fault expansion slot hole 3-5 is outside the broken rock area, and full rock fault broken rock hole 3-6 is arranged every 1.2m with 3 broken rock holes outside full rock fault expansion slot hole 3-5 until the edge of the area to be blasted; the diameter of each broken rock hole is 42mm, and the middle distance of each row of broken rock holes is 1.0m. The row distance is 1.2m, and each broken rock hole is drilled perpendicular to the working face, and the hole depth of each broken rock hole is 3.2m.

[0024] If it is full rock fault, full rock fault first order cut hole 3-1 is charged 2.5kg, among which hole bottom is charged 1.5kg after installing digital electronic detonator, then a part of blast hole is blocked with sticky loess, 1.0kg is continuously charged and digital electronic detonator is installed, finally blast hole is blocked with sticky loess again; full rock fault second order cut hole 3-2, full rock fault third order cut hole 3-3 and full rock fault fourth order cut hole 3-4 are charged 1.9kg after installing digital electronic detonator in the same way, then a part of blast hole is blocked with sticky loess, 1.0kg is continuously charged and digital electronic detonator is installed, finally blast hole is blocked with sticky loess again; full rock fault first order cut hole 3-1, full rock fault second order cut hole 3-2, full rock fault third order cut hole 3-3 and full rock fault fourth order cut hole 3-4 are blasted in large series, the explosive in full rock fault first order cut hole 3-1 is detonated by I section digital electronic detonator, which creates new free surface for full rock fault second order cut hole 3-2, the explosive in full rock fault second order cut hole 3-2 is detonated by II section digital electronic detonator, which creates new free surface for full rock fault third order cut hole 3-3, the explosive in full rock fault third order cut hole 3-3 is detonated by III section digital electronic detonator, which creates new free surface for full rock fault fourth order cut hole 3-4, the explosive in full rock fault fourth order cut hole 3-4 is detonated by IV section digital electronic detonator, the cut zone after cut hole blasting provides new free surface for expansion slot zone blasting.

[0025] The step four includes the following contents:

[0026] If it is full rock fault, full rock fault first order cut hole 3-1 is charged 2.5kg, among which hole bottom is charged 1.5kg after installing digital electronic detonator, then a part of blast hole is blocked with sticky loess, 1.0kg is continuously charged and digital electronic detonator is installed, finally blast hole is blocked with sticky loess again; full rock fault second order cut hole 3-2, full rock fault third order cut hole 3-3 and full rock fault fourth order cut hole 3-4 are charged 1.9kg after installing digital electronic detonator in the same way, then a part of blast hole is blocked with sticky loess, 1.0kg is continuously charged and digital electronic detonator is installed, finally blast hole is blocked with sticky loess again; full rock fault first order cut hole 3-1, full rock fault second order cut hole 3-2, full rock fault third order cut hole 3-3 and full rock fault fourth order cut hole 3-4 are blasted in large series, the explosive in full rock fault first order cut hole 3-1 is detonated by I section digital electronic detonator, which creates new free surface for full rock fault second order cut hole 3-2, the explosive in full rock fault second order cut hole 3-2 is detonated by II section digital electronic detonator, which creates new free surface for full rock fault third order cut hole 3-3, the explosive in full rock fault third order cut hole 3-3 is detonated by III section digital electronic detonator, which creates new free surface for full rock fault fourth order cut hole 3-4, the explosive in full rock fault fourth order cut hole 3-4 is detonated by IV section digital electronic detonator, the cut zone after cut hole blasting provides new free surface for expansion slot zone blasting.

[0027] If it is a full rock fault, each slot hole and each rock breaking hole is charged with 2.5 kg, wherein the hole bottom is charged with 1.5 kg, then a digital electronic detonator is installed, then a part of the blast hole is blocked with sticky loess, 1.0 kg of charge is continuously charged and a digital electronic detonator is installed, and finally the blast hole is fully blocked with sticky loess; for the slot hole, the digital electronic detonator at the hole mouth is a section I digital electronic detonator, and the digital electronic detonator at the hole bottom is a section II digital electronic detonator; for the rock breaking hole, the digital electronic detonator at the hole mouth is a section III digital electronic detonator, and the digital electronic detonator at the hole bottom is a section IV digital electronic detonator, and the slot zone and the rock breaking zone are blasted at the same time.

[0028] The beneficial effects of the present application are: different slotting positions are determined according to the fault rock mass structure type, multi-stage slotting segmented millisecond blasting technology is adopted to realize the goal of expanding and deepening the slotting zone, the columnar charging segmented millisecond blasting technology is adopted for the slot zone and the rock breaking zone to solve the problems of large residual hole depth and large gangue block, the slotting zone depth is ensured to be more than 3 m, the slotting blasting once meets the requirement of 4 times of working face cycle footage, and finally the blasting effect of deep slotting depth, short gangue throwing distance, small gangue block size and weak damage to surrounding rock is realized for the working face passing through the fault in the coal mine underground. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a fault profile schematic diagram of the working face in the coal mine underground of the present application.

[0030] Figure 2 It is a slotting hole arrangement schematic diagram of the fault containing coal seam of the present application.

[0031] Figure 3 It is a slotting hole angle schematic diagram of the fault containing coal seam of the present application.

[0032] Figure 4 It is a slotting hole arrangement schematic diagram of the full rock fault of the present application.

[0033] Figure 5 It is a slotting hole angle schematic diagram of the full rock fault of the present application.

[0034] Figure 6 It is a slotting hole charging schematic diagram of the fault containing coal seam of the present application, wherein a) is a first-order slotting hole charging schematic diagram of the coal seam, and b) is a slotting hole charging schematic diagram of other orders of the coal seam.

[0035] Figure 7 It is a slotting hole charging schematic diagram of the full rock fault of the present application, wherein a) is a first-order slotting hole charging schematic diagram of the full rock fault, and b) is a slotting hole charging schematic diagram of other orders of the full rock fault.

[0036] Figure 8 It is a slotting hole and rock breaking hole charging schematic diagram of the present application.

[0037] 1-1, working face, 1-2, coal seam, 1-3, fault, 1-4, roof, 1-5, floor, 1-6, to-be-blasted area, 2-1, coal interlayer first-order cut hole, 2-2, coal interlayer second-order cut hole, 2-3, coal interlayer third-order cut hole, 2-4, coal interlayer fourth-order cut hole, 2-5, coal interlayer fifth-order cut hole, 2-6, fault interlayer expansion hole, 2-7, fault interlayer first rock breaking hole, 2-8, fault interlayer second rock breaking hole, 2-9, fault interlayer cut area, 2-10, fault interlayer expansion area, 2-11, fault interlayer rock breaking area, 3-1, full rock fault first-order cut hole, 3-2, full rock fault second-order cut hole, 3-3, full rock fault third-order cut hole, 3-4, full rock fault fourth-order cut hole, 3-5, full rock fault expansion hole, 3-6, full rock fault rock breaking hole, 3-7, full rock fault cut area, 3-8, full rock fault expansion area, 3-9, full rock fault rock breaking area, 4-1, coal interlayer first-order cut hole bottom explosive, 4-2, coal interlayer first-order cut hole detonation point detonator, 4-3, coal interlayer first-order cut hole hole internal plug, 4-4, coal interlayer first-order cut hole hole mouth explosive, 4-5, coal interlayer first-order cut hole hole bottom plug, 4-6, coal interlayer other-order cut hole bottom explosive, 4-7, coal interlayer other-order cut hole detonation point detonator, 4-8, coal interlayer other-order cut hole hole internal plug, 4-9, coal interlayer other-order cut hole hole mouth explosive, 4-10, coal interlayer other-order cut hole hole bottom plug, 5-1, full rock fault first-order cut hole bottom explosive, 5-2, full rock fault first-order cut hole detonation point detonator, 5-3, full rock fault first-order cut hole hole internal plug, 5-4, full rock fault first-order cut hole hole mouth explosive, 5-5, full rock fault first-order cut hole hole bottom plug, 5-6, full rock fault other-order cut hole bottom explosive, 5-7, full rock fault other-order cut hole detonation point detonator, 5-8, full rock fault other-order cut hole hole internal plug, 5-9, full rock fault other-order cut hole hole mouth explosive, 5-10, full rock fault other-order cut hole hole bottom plug, 6-1, expansion hole and rock breaking hole bottom explosive, 6-2, expansion hole and rock breaking hole bottom detonation point detonator, 6-3, expansion hole and rock breaking hole hole internal plug, 6-4, expansion hole and rock breaking hole hole mouth explosive, 6-5, expansion hole and rock breaking hole hole mouth detonation point detonator, 6-6, expansion hole and rock breaking hole hole bottom plug. DETAILED DESCRIPTION

[0038] In order to have a clearer understanding of the technical features and objectives of the present application, the technical solutions of the present application will be described in detail below with reference to the drawings in the specification, but it should not be understood as limiting the scope of implementation of the present application.

[0039] The application discloses a multi-order slotting blasting method for passing through different structure faults of a coal mine underground working face.

[0040] The application discloses a multi-order slotting blasting method for passing through different structure faults of a coal mine underground working face.

[0041] Step one: according to the rock mass structure characteristics of the coal mine underground blasting area 1-6, based on the blasting theory and field test, the slotting rock stratum, position and angle are determined, and red paint is used for marking, and the hole drilling work of the slotting area (including the fault 2-9 of the coal seam, the full rock fault slotting area 3-7) is completed.

[0042] In the advancing process of the coal mine underground working face 1-1, the roof 1-4 and the floor 1-5 of the coal seam 1-2 are often dislocated to form the fault 1-3 due to the tectonic stress, and the corresponding fault rock mass is generally the roof 1-4 or the floor 1-5 of the coal seam 1-2, which has a higher hardness relative to the coal seam and cannot be directly passed through by the coal mining machine, so that the fault rock mass, i.e., the blasting area 1-6, needs to be reasonably weakened by blasting, so as to not affect the normal production of the working face 1-1.

[0043] If the blasting area 1-6 contains a coal seam, and the thickness of the coal seam is greater than 40 cm, the coal seam fault is treated. If the thickness of the coal seam is less than 40 cm, the full rock fault is treated. According to the actual distribution of the coal mine underground working face 1-1 encountering the fault 1-3, the length of the blasting area 1-6 that needs to be blasted is determined, and the middle range 2 m of the length of the blasting area 1-6 is measured by a tape measure as the arrangement position of the slotting area. The slotting hole of the coal seam fault is arranged in the middle range of the coal seam, and the slotting hole is marked by red paint in the slotting area. Five slotting holes are arranged along the horizontal direction at an angle of 60°, the hole diameter is 42 mm, the interval is 50 cm, the vertical depth of the first slotting hole 2-1 of the coal seam is 2.8 m, and the vertical depths of the other slotting holes are 3.2 m.

[0044] If there is no coal seam in the fault or the thickness of the coal seam is less than 40 cm, a full rock fault fourth order slot hole needs to be arranged on the full rock fault, 3-1 is a full rock fault first order slot hole, 3-2 is a full rock fault second order slot hole, 3-3 is a full rock fault third order slot hole, and 3-4 is a full rock fault fourth order slot hole. Similarly, the middle range 0.5 m of the length of the to-be-blasted area 1-6 is measured as a slot area by using a tape measure, and then the slot hole is marked. Eight slot holes are arranged along the vertical direction at an angle of 60°, the hole diameter is 42 mm, the interval and the row distance are both 50 cm, the vertical depth of the full rock fault first order slot hole 3-1 is 2.8 m, and the vertical depth of the other order slot holes is 3.2 m.

[0045] Step 2: Mark the slot holes (including the coal seam fault slot hole 2-6 and the full rock fault slot hole 3-5) and the rock breaking holes (including the coal seam fault first rock breaking hole 2-7, the coal seam fault second rock breaking hole 2-8, and the full rock fault rock breaking hole 3-6) with red paint, and arrange vertical holes in the slot area (including the coal seam fault slot area 2-10 and the full rock fault slot area 3-8) and the rock breaking area (including the coal seam fault rock breaking area 2-11 and the full rock fault rock breaking area 3-9) according to the blasting design scheme.

[0046] If it is a coal seam fault, slot holes, i.e. coal seam fault slot holes 2-6, are arranged 80 cm above and below the coal seam fault slot hole, the interval of the coal seam fault slot hole 2-6 is 80 cm, the hole diameter is 42 mm, the hole is perpendicular to the working face, and the hole depth is 3.2 m. The coal seam fault first rock breaking hole 2-7 is arranged 1.0 m away from the coal seam fault slot hole, the coal seam fault second rock breaking hole 2-8 is arranged 1.2 m away from the coal seam fault first rock breaking hole, and the coal seam fault third rock breaking hole is arranged 1.2 m away from the coal seam fault second rock breaking hole. In this way, the arrangement is continued until the edge of the to-be-blasted area is reached. The diameter of all the rock breaking holes is 42 mm, the row distance is 1.0 m, the hole is perpendicular to the working face, and the hole depth is 3.2 m.

[0047] If it is a full rock fault, a row of full rock fault slot holes 3-5 is arranged 1.0 m away from the full rock fault slot hole, the interval of the full rock fault slot hole is 1.0 m, the hole diameter is 42 mm, the hole is perpendicular to the working face, and the hole depth is 3.2 m. The first row of full rock fault rock breaking holes 3-6 is arranged 1.2 m away from the slot hole, the second row of full rock fault rock breaking holes is arranged 1.2 m away from the first row of full rock fault rock breaking holes, and the third row of rock breaking holes is arranged 1.2 m away from the second row of full rock fault rock breaking holes. In this way, the arrangement is continued until the edge of the to-be-blasted area is reached. The diameter of the rock breaking holes is 42 mm, the row distance is 1.0 m, the hole is perpendicular to the working face, and the hole depth is 3.2 m.

[0048] Step 3: According to the blasting design scheme, the slotted holes (coal seam interlayer first-order slotted holes~coal seam interlayer fifth-order slotted holes 2-1~2-5, whole rock fault first-order~whole rock fault fourth-order slotted holes 3-1~3-4) are filled with digital electronic detonators and explosives, and the slotted hole area (including coal fault slotted area 2-9, whole rock fault slotted area 3-7) is completed for explosive filling, plugging, wiring and blasting work.

[0049] In the blasting scheme of the present application, all the explosives in the slotted holes are coal mine permissible No. 3 emulsion explosives, the diameter of the explosive is 35 mm, the uncoupling charge coefficient is 1.2, and the linear charge density is 1 kg / m3. Two initiation points in each slotted hole are initiated by the same type of digital electronic detonator, and the wiring mode is large series connection. The initiation points in each hole are initiated by a special blasting machine for digital electronic detonators;

[0050] If it contains a coal fault, the coal seam interlayer first-order slotted hole 2-1 is charged with 2.2 kg, and the coal seam interlayer first-order slotted hole bottom charge reaches 1.2 kg and 1.2 m after which the coal seam first-order slotted hole initiation point detonator 4-2 is installed, the 0.5 m is plugged with viscous loess as the coal seam interlayer first-order slotted hole internal plug 4-3, 1.0 kg is continuously charged, the coal seam first-order slotted hole initiation point detonator 4-2 is installed again, and finally the coal seam interlayer first-order slotted hole bottom plug 4-5 is filled with viscous loess. The other coal fault slotted hole is charged with 2.7 kg, and the coal seam other order slotted hole initiation point detonator 4-7 is installed after the bottom charge of 1.7 kg, the 0.5 m is plugged with viscous loess as the coal seam other order slotted hole internal plug 4-8, 1.0 kg is continuously charged, the coal seam other order slotted hole initiation point detonator 4-7 is installed again, and finally the coal seam other order slotted hole bottom plug 4-10 is filled with viscous loess. The coal seam interlayer first-order slotted hole 2-1~coal seam interlayer fifth-order slotted hole 2-5 is initiated by large series connection, and different order slotted holes are initiated by different detonator segments to achieve the effect of micro-difference initiation. The coal seam interlayer first-order slotted hole bottom explosive 4-1 and the coal seam interlayer first-order slotted hole mouth explosive 4-4 in the coal seam interlayer first-order slotted hole 2-1 are initiated by the coal seam first-order slotted hole initiation point detonator 4-2, which creates a new free surface for the coal seam interlayer second-order slotted hole 2-2. It should be noted that the coal seam first-order slotted hole initiation point detonator 4-2 is a I segment digital electronic detonator;

[0051] The coal seam other order slotted hole bottom explosive 4-6 and the coal seam other order slotted hole mouth explosive 4-9 in the coal seam interlayer second-order slotted hole 2-2 are initiated by the coal seam other order slotted hole initiation point detonator 4-7, which creates a new free surface for the coal seam interlayer third-order slotted hole 2-3. It should be noted that the coal seam other order slotted hole initiation point detonator 4-7 is a II segment digital electronic detonator;

[0052] The coal seam other order slot hole bottom explosive 4-6 and the coal seam other order slot hole mouth explosive 4-9 in the coal interlayer third order slot hole 2-3 are detonated by the coal seam other order slot initiation point detonator 4-7, a new free surface is created for the coal interlayer fourth order slot hole 2-4, and it should be noted that the coal seam other order slot initiation point detonator 4-7 is a III section digital electronic detonator; the coal seam other order slot hole bottom explosive 4-6 and the coal seam other order slot hole mouth explosive 4-9 in the coal interlayer fourth order slot hole 2-4 are detonated by the coal seam other order slot initiation point detonator 4-7, a new free surface is created for the coal interlayer fifth order slot hole 2-5, and it should be noted that the coal seam other order slot initiation point detonator 4-7 is a IV section digital electronic detonator; the coal seam other order slot hole bottom explosive 4-6 and the coal seam other order slot hole mouth explosive 4-9 in the coal interlayer fifth order slot hole 2-5 are detonated by the coal seam other order slot initiation point detonator 4-7, and it should be noted that the coal seam other order slot initiation point detonator 4-7 is a V section digital electronic detonator; the coal interlayer slotting zone 2-9 after the fault slotting hole blasting provides a new free surface for the fault slotting zone 2-10 and the fault rock breaking zone 2-11.

[0053] If it is a full rock fault, two full rock fault first order slot holes 3-1 are respectively loaded with 2.5 kg of explosive, the full rock fault first order slot hole bottom explosive 5-1 is loaded with 1.5 kg of explosive, and after 1.5 m, the full rock fault first order slot initiation point detonator 5-2 is installed, 0.3 m of viscous loess is used as the full rock fault first order slot hole internal plug 5-3, the full rock fault first order slot hole mouth explosive 5-4 is continuously loaded with 1.0 kg of explosive, the full rock fault first order slot initiation point detonator 5-2 is installed again, and finally the full rock fault first order slot hole is fully plugged with viscous loess as the full rock fault first order slot hole bottom plug 5-5.

[0054] Each hole of the full rock fault second order slot hole to the full rock fault fourth order slot hole is loaded with 2.9 kg of explosive, among which the full rock fault other order slot hole bottom explosive 5-6 is loaded with 1.9 kg of explosive, then the full rock fault other order slot initiation point detonator 5-7 is installed, 0.3 m of viscous loess is used as the full rock fault other order slot hole internal plug 5-8, the full rock fault other order slot hole mouth explosive 5-9 is continuously loaded with 1.0 kg of explosive, the full rock fault other order slot initiation point detonator 5-7 is installed again, and finally the full rock fault other order slot hole is fully plugged with viscous loess as the full rock fault other order slot hole bottom plug 5-10.

[0055] The full rock fault first order slot hole to the full rock fault fourth order slot hole are detonated in large series, and different sections of detonators are used to achieve the effect of micro-difference detonation.

[0056] The whole rock fault first-order cut hole bottom explosive 5-1 and the whole rock fault first-order cut hole mouth explosive 5-4 in the whole rock fault first-order cut hole 3-1 are detonated by using the whole rock fault first-order cut hole initiation point detonator 5-2, a new free surface is created for the whole rock fault second-order cut hole 3-2, and it should be noted that the whole rock fault first-order cut hole initiation point detonator 5-2 uses a section I digital electronic detonator.

[0057] The whole rock fault other-order cut hole bottom explosive 5-6 and the whole rock fault other-order cut hole mouth explosive 5-9 in the whole rock fault second-order cut hole 3-2 are detonated by using the whole rock fault other-order cut hole initiation point detonator 5-7, a new free surface is created for the whole rock fault third-order cut hole 3-3, and it should be noted that the whole rock fault other-order cut hole initiation point detonator 5-7 uses a section II digital electronic detonator.

[0058] The whole rock fault other-order cut hole bottom explosive 5-6 and the whole rock fault other-order cut hole mouth explosive 5-9 in the whole rock fault third-order cut hole 3-3 are detonated by using the whole rock fault other-order cut hole initiation point detonator 5-7, a new free surface is created for the whole rock fault fourth-order cut hole 3-4, and it should be noted that the whole rock fault other-order cut hole initiation point detonator 5-7 uses a section III digital electronic detonator.

[0059] The whole rock fault other-order cut hole bottom explosive 5-6 and the whole rock fault other-order cut hole mouth explosive 5-9 in the whole rock fault fourth-order cut hole 3-4 are detonated by using the whole rock fault other-order cut hole initiation point detonator 5-7, and it should be noted that the whole rock fault other-order cut hole initiation point detonator 5-7 uses a section IV digital electronic detonator.

[0060] The whole rock fault cut hole blasting area 3-7 after the whole rock fault cut hole blasting provides a new free surface for the whole rock fault cut area 3-8 blasting, and the whole rock fault cut area 3-8 after the whole rock fault cut hole blasting provides a new free surface for the whole rock fault rock breaking area 3-9 blasting.

[0061] Step 4: according to the blasting design scheme, the digital electronic detonator and explosive are filled in the cut area and the rock breaking area, and the explosive filling, sealing, wiring and blasting of the cut area and the rock breaking area are completed.

[0062] In the blasting scheme of the application, all the explosives in the cut and rock breaking holes are coal mine permissible No. 3 emulsion explosives, the diameter of the explosive is 35 mm, the uncoupling charge coefficient is 1.2, and the linear charge density is 1 kg / m3. Two initiation points in the cut and rock breaking holes use different section digital electronic detonators, and the section of the hole mouth detonator is smaller than the section of the hole bottom, the wiring mode is large series connection, and the digital electronic detonator special blasting machine is used to detonate the initiation points in the holes.

[0063] If it is a fault zone, each fault zone slot hole and rock breaking hole (fault zone slot hole 2-6, fault zone first rock breaking hole 2-7, fault zone second rock breaking hole 2-8) is charged with 2.5kg, wherein the slot hole and rock breaking hole bottom explosive 6-1 is charged with 1.5kg and 1.5m after the installation of slot hole and rock breaking hole bottom initiation point detonator 6-2, the slot hole and rock breaking hole hole is blocked with 0.3m of clay as the slot hole and rock breaking hole hole block 6-3, the slot hole and rock breaking hole hole mouth explosive 6-4 is continuously charged with 1.0kg, and then the slot hole and rock breaking hole hole mouth initiation point detonator 6-5 is installed, and finally the slot hole and rock breaking hole hole is filled with clay as the slot hole and rock breaking hole hole bottom block 6-6. The slot hole and rock breaking hole hole mouth explosive 6-4 is detonated by the slot hole and rock breaking hole hole mouth initiation point detonator 6-5, wherein the slot hole and rock breaking hole hole mouth initiation point detonator 6-5 uses a section digital electronic detonator, and the slot hole and rock breaking hole hole bottom explosive 6-1 is detonated by the slot hole and rock breaking hole hole bottom initiation point detonator 6-2, wherein the slot hole and rock breaking hole hole bottom initiation point detonator 6-2 uses a section digital electronic detonator.

[0064] The slot hole and rock breaking hole hole mouth explosive 6-4 is first detonated, which breaks the rock at the hole mouth and at the same time provides a weak blasting rock mass for the hole bottom charge, ensuring the depth of blasting. The formation of the fault zone slotting area 2-9 and the fault zone slotting area 2-10 provides a new free surface for the blasting of the rock breaking area, ensuring that the rock breaking hole (fault zone first rock breaking hole 2-7, fault zone second rock breaking hole 2-8) can be blasted to the designed depth. The slot hole and rock breaking hole hole bottom explosive 6-1 of the fault zone first rock breaking hole 2-7 next to the fault zone slotting area and the fault zone slotting area is detonated by the slot hole and rock breaking hole hole bottom initiation point detonator 6-2, wherein the slot hole and rock breaking hole hole bottom initiation point detonator 6-2 uses a section digital electronic detonator.

[0065] The slot hole and rock breaking hole hole mouth explosive 6-4 is detonated by the slot hole and rock breaking hole hole mouth initiation point detonator 6-5, wherein the slot hole and rock breaking hole hole bottom initiation point detonator 6-2 uses a section digital electronic detonator.

[0066] The slot hole and rock breaking hole hole bottom explosive 6-1 of the fault zone second rock breaking hole 2-8 hole bottom is detonated by the slot hole and rock breaking hole hole bottom initiation point detonator 6-2, wherein the slot hole and rock breaking hole hole bottom initiation point detonator uses a section digital electronic detonator, and the slot hole and rock breaking hole hole mouth explosive 6-4 is detonated by the slot hole and rock breaking hole hole mouth initiation point detonator 6-5, wherein the slot hole and rock breaking hole hole bottom initiation point detonator 6-2 uses a section digital electronic detonator. It should be noted that the fault zone should be blasted after the slotting area 2-10 is blasted.

[0067] If it is full rock fault, full rock fault slotting hole 3-5 and full rock fault breaking hole 3-6 are charged with 2.5kg of explosives, wherein the slotting hole and the breaking hole are charged with 1.5kg of explosives at the bottom of the hole, 1.5m after which the slotting hole and the breaking hole are charged with a bottom detonation point detonator 6-2, the slotting hole and the breaking hole are blocked with 0.3m of clayey loess as hole blocking 6-3, the slotting hole and the breaking hole are charged with 1.0kg of explosives at the hole mouth, the slotting hole and the breaking hole are charged with a hole mouth detonation point detonator 6-5, and finally the slotting hole and the breaking hole are blocked with clayey loess as hole blocking 6-6. The slotting hole and the breaking hole are detonated by the hole mouth detonation point detonator 6-5, wherein the hole mouth detonation point detonator 6-5 is a Ⅰ-stage digital electronic detonator, the slotting hole and the breaking hole are detonated by the bottom detonation point detonator 6-2, wherein the bottom detonation point detonator 6-2 is a Ⅱ-stage digital electronic detonator. The slotting area 3-8 of the full rock fault is formed to provide a new free surface for the breaking area 3-9 of the full rock fault, which ensures that the breaking hole can be blasted to the designed depth. The slotting hole and the breaking hole are detonated by the hole mouth detonation point detonator 6-5, wherein the hole mouth detonation point detonator 6-5 is a Ⅲ-stage digital electronic detonator, the slotting hole and the breaking hole are detonated by the bottom detonation point detonator 6-2, wherein the bottom detonation point detonator 6-2 is a Ⅳ-stage digital electronic detonator. It should be noted that the slotting area and the breaking area of the full rock fault are blasted simultaneously.

[0068] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described by referring to the embodiments of the present application, those skilled in the art should understand that various changes can be made in form and details without departing from the spirit and scope of the present application as defined by the appended claims, and all such changes should be included in the scope of the claims of the present application.

[0069] The working face of a mine in Shanxi was studied. The fault rock mass was limestone with a firm coefficient f>8. Some faults were fault rock containing coal, and the other faults were full rock faults. The fault to be blasted had a height of 3.0m, a length of 20m, and a depth of 20m.

[0070] The original construction scheme adopts the drill-and-blast method, and the specific method is to drill 2.4m blast holes vertically to the fault direction, the blast hole row number is 2 rows, and the row distance and the interval are both 1.5m. After each blasting, the residual hole length reaches more than 1.2m, and the gangue block size is large, which cannot be directly discharged through the underground transportation system, and a large amount of manpower and time is needed to break the large gangue into small pieces by using a pneumatic pick, which increases the construction cost and the labor cost. The phenomenon of throwing gangue far away and damaging the equipment behind the working face often occurs. In addition, the working face cuts coal in two cycles per day, with an average footage of 1.2m, which seriously affects the production progress of the working face.

[0071] The new scheme adopts the multi-order cutting blasting method for passing through different structure faults at the underground working face according to the present application, and the drilling and blasting parameters and the construction process are designed based on this. The test results show that the single cutting depth can be maintained at more than 2.9m, the depth of the expansion groove area and the rock breaking area can be guaranteed to be more than 2.8m, there is no obvious large gangue after blasting, which meets the underground transportation requirements, the gangue throwing distance is relatively short, and there is no phenomenon of damaging the equipment behind the working face, and four cutting cycles per day can be guaranteed, with an average footage of 3.0m, which ensures the production progress of the working face.

Claims

1. A multi-step cut blasting method for passing different structure faults of a coal mine underground working face, characterized in that: Comprising the following steps: Step one, according to the situation of coal mine working face (1-1) encountered fault (1-3) to determine the blasting area (1-6), based on the characteristics of the blasting area (1-6) rock, determine the position of the slotting area, then determine the position and angle of the slotting hole and mark, and then complete the slotting hole work; The action of underground structure stress causes the roof (1-4) and floor (1-5) of coal seam (1-2) to be dislocated to form fault (1-3), when the coal mine working face (1-1) encounters fault (1-3) in the process of advancing, because the area of fault (1-3) is higher than that of coal seam, it can't pass through directly by using coal mining machine, it needs to be weakened by blasting in this area to facilitate the passing of coal mining machine, the area that needs to be weakened by blasting is the blasting area (1-6); If the coal seam is contained in the blasting area (1-6), and the thickness of the coal seam is greater than or equal to 40 cm, it is defined as coal seam fault, the coal seam in the middle of the blasting area (1-6) is taken as the slotting area, and a row of five slotting holes, namely coal seam slotting holes, are arranged in the slotting area at equal intervals, which are coal seam first-order slotting hole (2-1), coal seam second-order slotting hole (2-2), coal seam third-order slotting hole (2-3), coal seam fourth-order slotting hole (2-4) and coal seam fifth-order slotting hole (2-5) in turn, the hole diameter of each coal seam slotting hole is 42 mm, the spacing between adjacent coal seam slotting holes is 50 cm, the angle between each coal seam slotting hole and the horizontal direction is 60°, the vertical depth of the coal seam first-order slotting hole (2-1) is 2.8 m, and the vertical depth of the coal seam second-order slotting hole (2-2), the coal seam third-order slotting hole (2-3), the coal seam fourth-order slotting hole (2-4) and the coal seam fifth-order slotting hole (2-5) is 3.2 m; If there is no coal seam or the thickness of the coal seam is less than 40 cm in the blasting area (1-6), it is defined as full rock fault, and the middle range of 50 cm in the blasting area (1-6) is taken as the slotting area, eight slotting holes, namely full rock fault slotting holes, are arranged in the slotting area at a spacing and row distance of 50 cm, which are full rock fault first-order slotting hole (3-1), full rock fault second-order slotting hole (3-2), full rock fault third-order slotting hole (3-3) and full rock fault fourth-order slotting hole (3-4) in turn from the first row of slotting holes to the fourth row of slotting holes, the hole diameter of each full rock fault slotting hole is 42 mm, the angle between each full rock fault slotting hole and the vertical direction is 60°, the vertical depth of the full rock fault first-order slotting hole (3-1) is 2.8 m, and the vertical depth of the full rock fault second-order slotting hole (3-2), the full rock fault third-order slotting hole (3-3) and the full rock fault fourth-order slotting hole (3-4) is 3.2 m; Step two, determine the position of the slotting area according to the position of the slotting hole, and then determine the position and angle of the slotting hole and mark, and then determine the position of the rock breaking area, and then determine the position and angle of the rock breaking hole and mark, and finally complete the drilling work of the slotting area and the rock breaking area; Step three, filling digital electronic detonator and explosive in the slot hole, complete the slot hole of explosive filling, sealing, wiring and shooting work; Step four, filling digital electronic detonator and explosive in the slot hole and rock breaking hole, complete the slot hole and rock breaking hole of explosive filling, sealing, wiring and shooting work.

2. The multi-step cut blasting method for passing different structure faults of coal mine underground working face according to claim 1, characterized in that: Step two includes the following contents: If it is a coal seam fault, the upper 80 cm of the coal seam slot hole and the lower 80 cm of the coal seam slot hole are the slotting area, and the slotting hole (2-6) is two rows of three columns of six, which is arranged in the center of the slotting area. The distance between each row of slotting holes (2-6) is 80 cm, each slotting hole (2-6) is perpendicular to the working face, the diameter of each slotting hole (2-6) is 42 mm, and the depth of each slotting hole (2-6) is 3.2 m; If it is a full rock fault, the two columns of full rock fault slot holes are opposite to the inside and opposite to the outside, the first column of full rock fault slot holes is 1 m outside and the second column of full rock fault slot holes is 1 m outside. The slotting area is 1 m outside the second column of full rock fault slot holes, and the slotting hole (3-5) is three rows of two columns of six, which is arranged in the center of the slotting area. The distance between each column of full rock fault slot holes (3-5) is 1 m, each full rock fault slot hole (3-5) is perpendicular to the fault plane, the diameter of each full rock fault slot hole (3-5) is 42 mm, and the depth of each full rock fault slot hole (3-5) is 3.2 m.

3. The multi-step cut blasting method for passing different structure faults of coal mine underground working face according to claim 2, characterized in that: Step two includes the following contents: If it is a coal seam fault, the left side of the coal seam slot hole (2-1) and the right side of the coal seam slot hole (2-5) are the rock breaking area; One column of three coal seam first rock breaking holes (2-7) is arranged 1 m to the left of the coal seam slot hole (2-1), one column of three coal seam second rock breaking holes (2-8) is arranged 1.2 m to the left of the coal seam first rock breaking hole (2-7) to the left of the coal seam slot hole (2-1), and one column of three coal seam third rock breaking holes is arranged 1.2 m to the left of the coal seam second rock breaking hole (2-8) to the left of the coal seam slot hole (2-1). The same goes for the right side of the coal seam slot hole (2-5); The diameter of each rock breaking hole is 42 mm, the distance between each column of rock breaking holes is 1.0 m, each rock breaking hole is perpendicular to the fault plane, and the depth of each rock breaking hole is 3.2 m; If it is a coal seam fault, the left side of the coal seam slot hole (2-1) and the right side of the coal seam slot hole (2-5) are the rock breaking area; One column of three coal seam first rock breaking holes (2-7) is arranged 1 m to the left of the coal seam slot hole (2-1), one column of three coal seam second rock breaking holes (2-8) is arranged 1.2 m to the left of the coal seam first rock breaking hole (2-7) to the left of the coal seam slot hole (2-1), and one column of three coal seam third rock breaking holes is arranged 1.2 m to the left of the coal seam second rock breaking hole (2-8) to the left of the coal seam slot hole (2-1). The same goes for the right side of the coal seam slot hole (2-5); The diameter of each rock breaking hole is 42 mm, the distance between each column of rock breaking holes is 1.0 m, each rock breaking hole is perpendicular to the fault plane, and the depth of each rock breaking hole is 3.2 m; If it is a full rock fault, the full rock fault slotting hole (3-5) is outside the rock breaking area, and a row of three rock breaking holes, i.e. full rock fault rock breaking holes (3-6), are arranged every 1.2m outside the full rock fault slotting hole (3-5) until the edge of the fault; the diameter of each rock breaking hole is 42mm, the row distance of each row of rock breaking holes is 1.0m, each rock breaking hole is drilled perpendicular to the fault plane, and the hole depth of each rock breaking hole is 3.2m.

4. The multi-step cut blasting method for passing different structure faults of coal mine underground working face according to claim 3, characterized in that: The step three includes the following contents: If it is a full rock fault, the full rock fault slotting hole (3-5) is outside the rock breaking area, and a row of three rock breaking holes, i.e. full rock fault rock breaking holes (3-6), are arranged every 1.2m outside the full rock fault slotting hole (3-5) until the edge of the fault; the diameter of each rock breaking hole is 42mm, the row distance of each row of rock breaking holes is 1.0m, each rock breaking hole is drilled perpendicular to the fault plane, and the hole depth of each rock breaking hole is 3.2m. The step three includes the following contents: If it is a full rock fault, the full rock fault slotting hole (3-5) is outside the rock breaking area, and a row of three rock breaking holes, i.e. full rock fault rock breaking holes (3-6), are arranged every 1.2m outside the full rock fault slotting hole (3-5) until the edge of the fault; the diameter of each rock breaking hole is 42mm, the row distance of each row of rock breaking holes is 1.0m, each rock breaking hole is drilled perpendicular to the fault plane, and the hole depth of each rock breaking hole is 3.2m. The step three includes the following contents: If it is a full rock fault, the full rock fault slotting hole (3-5) is outside the rock breaking area, and a row of three rock breaking holes, i.e. full rock fault rock breaking holes (3-6), are arranged every 1.2m outside the full rock fault slotting hole (3-5) until the edge of the fault; the diameter of each rock breaking hole is 42mm, the row distance of each row of rock breaking holes is 1.0m, each rock breaking hole is drilled perpendicular to the fault plane, and the hole depth of each rock breaking hole is 3.2m. If it is a full rock fault, the first-order undercut hole (3-1) of the full rock fault is charged with 2.5 kg of explosives, among which 1.5 kg of explosives are charged at the bottom of the hole, then a digital electronic detonator is installed, then the hole is blocked with viscous loess, then 1.0 kg of explosives are continuously charged, then a digital electronic detonator is installed, and then the hole is filled with viscous loess again; the second-order undercut hole (3-2), the third-order undercut hole (3-3) and the fourth-order undercut hole (3-4) of the full rock fault are charged in the same way with 2.9 kg of explosives, among which 1.9 kg of explosives are charged at the bottom of the hole, then a digital electronic detonator is installed, then the hole is blocked with viscous loess, then 1.0 kg of explosives are continuously charged, then a digital electronic detonator is installed, and then the hole is filled with viscous loess again; the first-order undercut hole (3-1), the second-order undercut hole (3-2), the third-order undercut hole (3-3) and the fourth-order undercut hole (3-4) of the full rock fault are initiated by large series connection, two initiation points in each undercut hole are initiated by digital electronic detonators of the same segment, different undercut holes are initiated by digital electronic detonators of different segments, micro-difference initiation is realized, the explosives in the first-order undercut hole (3-1) are initiated by a digital electronic detonator of segment I, a new free surface is created for the second-order undercut hole (3-2), the explosives in the second-order undercut hole (3-2) are initiated by a digital electronic detonator of segment II, a new free surface is created for the third-order undercut hole (3-3), the explosives in the third-order undercut hole (3-3) are initiated by a digital electronic detonator of segment III, a new free surface is created for the fourth-order undercut hole (3-4), the explosives in the fourth-order undercut hole (3-4) are initiated by a digital electronic detonator of segment IV, and the undercut zone after the undercut hole blasting provides a new free surface for the expansion slot zone blasting.

5. The multi-step cut blasting method for passing different structure faults of coal mine underground working face according to claim 4, characterized in that: The step four includes the following contents: If it is a full rock fault, the first-order undercut hole (3-1) of the full rock fault is charged with 2.5 kg of explosives, among which 1.5 kg of explosives are charged at the bottom of the hole, then a digital electronic detonator is installed, then the hole is blocked with viscous loess, then 1.0 kg of explosives are continuously charged, then a digital electronic detonator is installed, and then the hole is filled with viscous loess again; for the expansion slot hole, the digital electronic detonator at the hole mouth is a digital electronic detonator of segment I, and the digital electronic detonator at the bottom of the hole is a digital electronic detonator of segment II, and the digital electronic detonator of segment I is initiated first; for the first rock breaking hole (2-7) of the coal-containing fault, the digital electronic detonator at the bottom of the hole is a digital electronic detonator of segment II, and the digital electronic detonator at the hole mouth is a digital electronic detonator of segment I, and for other rock breaking holes, the digital electronic detonator at the bottom of the hole is a digital electronic detonator of segment IV, and the digital electronic detonator at the hole mouth is a digital electronic detonator of segment III, and the rock breaking zone is blasted after the expansion slot zone is blasted; If it is full rock fault, each slot hole and each rock breaking hole is charged with 2.5 kg, wherein the hole bottom is charged with 1.5 kg, then a digital electronic detonator is installed, then it is blocked with sticky loess, then it is continuously charged with 1.0 kg, then a digital electronic detonator is installed, and then it is fully blocked with sticky loess again; for the slot hole, the digital electronic detonator at the hole mouth is a section I digital electronic detonator, and the digital electronic detonator at the hole bottom is a section II digital electronic detonator; for the rock breaking hole, the digital electronic detonator at the hole mouth is a section III digital electronic detonator, and the digital electronic detonator at the hole bottom is a section IV digital electronic detonator, and the slot area and the rock breaking area are blasted simultaneously.

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