CN116464458A - A layout structure for pre-splitting blasting through deep holes in excavation working face - Google Patents

Abstract

The invention relates to the technical field of underground coal mine drilling, in particular to a mining working face overstructured deep hole presplitting blasting layout structure which adopts a uncoupled continuous charging structure; the blasting Kong Jian is arranged in a regular triangle, the hole pitch, row number and column number are determined by loosening the expansion radius of the blasting cracks, and the hole depth is the sum of the working face-to-construction distance L and the construction length B; l is at least a first coal-rock cross-connection stop of drilling of the working surface, and B is a first coal-rock cross-connection stop and a second coal-rock cross-connection stop; the method has the beneficial effects that the hole pitch, the row number and the column number are determined by loosening the expansion radius of the blasting cracks, and the generation and the expansion of the cracks in the coal body are increased by the uncoupled continuous charging structure, so that the stress concentration degree in the coal body and the stability of a stope are reduced, and the optimal blasting effect generated by fewer blasting holes is realized; the drill rod position and the inclination angle are monitored in real time through measurement while drilling, so that the characteristics of high drilling accuracy and precision are improved, and the effect of pre-splitting blasting is improved.

Description

A layout structure for pre-splitting blasting through deep holes in excavation working face

technical field

The invention relates to the technical field of underground drilling in coal mines, in particular to a layout structure for pre-splitting blasting of deep holes through structures in excavation working faces.

Background technique

The fully mechanized mining machine excavation method has been popularized and used in coal mine rock roadway excavation. For the soft rock roadway with the Pu's hardness coefficient less than 6, the fully mechanized miner can cut smoothly and achieve high excavation efficiency. However, when the mining face encounters a hard structural rock formation and needs to be forced to advance, the mechanical parameters such as the strength and hardness of the medium have undergone great changes. For example, when encountering hard rock with a firmness greater than 6, the material consumption such as picks will be very serious when the fully mechanized mining machine is cutting, the equipment damage rate is high, and the advancing speed is also very slow. In view of this situation, before the excavation of the fully mechanized mining machine, the pre-splitting blasting method is usually used to drill the hard rock layer and charge the blasting. When the explosive explodes in the blast hole, it will generate a strong shock wave and high-pressure gas and violently impact the rock mass around the blast hole wall, causing the surrounding rock mass to break and crack. But at this stage, the small-diameter deep hole blasting method such as patent CN202210670144.2, CN202210367639.8 and the shallow hole blasting method such as patent CN202121613247.2 are mainly used. Because the loosening effect of small-diameter deep hole blasting is slightly poor, the range of loosening medium is small in shallow hole blasting, the number of blasting cycles is large, and the hole layout operation takes a long time, resulting in low hole layout efficiency, a significant increase in production costs, and a large increase in safety risks due to the number of blasting times.

For this reason, how to reduce the number of blasting times, improve the efficiency of hole layout, and set up fewer blasting holes to produce the best blasting effect in the over-structured structure remains to be solved.

Contents of the invention

In order to solve the problem that the number of blasting cycles in the pre-splitting blasting in the prior art is large and the hole layout operation time is long, the hole layout efficiency is low, the production cost is greatly increased, and the safety risk caused by the high number of blasting times is also greatly increased. A pre-splitting blasting layout structure for deep holes through the structure of the mining face is proposed. It has the characteristics of less blasting times, high hole layout efficiency, good pre-split blasting effect, and high safety.

A pre-splitting blasting layout structure for deep holes through a structure in a mining face, characterized in that it adopts an uncoupled continuous charge structure; the blasting holes are arranged in an equilateral triangle, and the hole spacing X, row spacing Y, row number h, and column number a meet the following requirements:

Expansion radius of crack according to loose burst

In the formula: r _t — crack extension radius;

P _r —peak value of initial radial stress of stress wave,

ν—Poisson's ratio; α—stress wave attenuation value; D—explosive detonation velocity; ρ ₀ —explosive density;

r _c —radius of charge volume; r _b —radius of blast hole; S _t —tensile strength of rock mass; n—coefficient of pressure increase;

Excavation face width A, height H,

Then a=ROUNDUP(A/(2r _t -r _b ),0), that is, A/(2r _t -r _b ) is rounded up, and the hole distance X=A/a

h=ROUNDUP((H/(2r _t -r _b )),0), that is, H/(2r _t -r _b ) is rounded up, row spacing Y=H/h;

Establish a Cartesian coordinate system with point F (0,0) on the structural section as the starting point of the X-axis and Y-axis, and drill holes at [(2m+0.5)X, (2n+0.5)Y], [(k*X, (2t-0.5)Y)], m=0,1,2,3...,

n=0,1,2,3...,k=1,2,3,...,t=1,2,3,...;

(2m+0.5)X<A, (2n+0.5)Y<H, k*X<A, (2t-0.5)Y<H;

The hole depth is the sum of the distance L from the working face to the structure and the length B of the structure; L is at least the first coal-rock transition in the working face, and B is the first coal-rock transition and the second coal-rock transition.

Further, the uncoupled charge structure includes a tube explosion-proof flame arrester, a tube explosive, an initiating charge and an electric detonator; the tube explosion-proof flame arrester is arranged at the inner end of the blast hole; the tube explosive is connected to the construction length B one by one and then pushed to the blast hole and is adjacent to the tube explosion-proof flame arrester; two priming charges are loaded at the back of the tube explosive, and each priming charge is connected in parallel to two electric detonators; The cable grows out of the outer end of the priming charge; the connecting wire of the electric detonator leads out of the blast hole, and the outside of the blast hole is sealed.

Further, the diameter of the blasting hole is 94mm, and the outer diameter of the shell explosive is 45mm-70mm.

Further, the outer diameter of the casing explosive is 63mm.

Further, the length of each section of the explosive in the casing is 800mm-900mm.

Further, the shelled explosive includes a drug core and a shell wrapped on the core, the two ends of the shell are respectively provided with connectors, and the connectors at both ends are respectively provided with internal and external threads capable of engaging with each other.

Further, the electric detonator is an instantaneous electric detonator or the same millisecond electric detonator.

The beneficial effects of the present invention are:

1. Determine hole spacing, row spacing, number of rows, and number of columns by loosening the blasting fracture expansion radius, and increase the generation and expansion of cracks in the coal body through the uncoupling continuous charge structure, reduce the stress concentration in the coal and rock body and the stability of the stope, so as to achieve the best blasting effect with fewer blasting holes; When the explosion gas expands and the detonation wave transmits its pressure to the hole wall rock through the air medium, it can buffer the explosion shock wave, which not only weakens the initial pressure peak acting on the blast hole, but also makes the pressure evenly distributed and prolongs the action time of the explosion gas, which is conducive to improving the blasting effect and making full use of the energy of the explosive. Explosive gas expansion can increase the generation and expansion of cracks in the coal body, which is beneficial to reduce the stress concentration in the coal and rock body and the stability of the stope; 3. Using large-diameter blast holes and uncoupled continuous charge structure, and connecting the barrel explosives to the construction length one by one and then sending them into the blast holes, it has the characteristics of simple structure and convenient placement of explosives in deep holes; using two electric detonators to detonate the priming charge can ensure the complete detonation of the priming charge, and the detonating cord can increase the explosive transmission speed and reduce the occurrence The probability of blast rejection ensures safety and stability; 4. The position and inclination angle of the drill pipe can be monitored in real time through measurement while drilling, and the drilling direction can be adjusted through the directional drill bit, thereby improving the accuracy and high precision of drilling, and helping to improve the effect of pre-splitting blasting.

Description of drawings

Figure 1 is a schematic diagram of the layout of the blasting holes of the deep hole pre-splitting blasting system;

Figure 2 is a schematic diagram of the blasting hole layout of the deep hole pre-splitting blasting system;

Fig. 3 is the structural representation of uncoupled continuous charge;

Fig. 4 is the schematic structural view of the shell explosive;

Fig. 5 is the structural representation of directional drilling system in the present invention;

Fig. 6 is the structural representation of directional drilling machine in the present invention;

Fig. 7 is the structural representation of anti-blowout separation device;

Fig. 8 is the structural representation of electronic water braid;

Fig. 9 is a structural schematic diagram of a cable drill pipe;

Fig. 10 is the structural representation of directional drill bit;

In the figure: 1. Directional drilling machine; 2. Electronic water braid; 3. Cable drill pipe; 4. Bottom-hole screw drilling tool; 5. Directional drill bit; 6. Measuring-while-drilling probe; 7. Power source; 8. Water supply pipe; 9. Blasting hole; 10. Explosion-proof air compressor; ;17, mine pool; 18, quilt tube explosion-proof flame suppressor; 19, quilt tube explosive; 20, detonating charge package; 21, electric detonator; 22, detonating cord; 23, outlet; 24, fixed end; 25, rotating end; 26, inlet; ;35, rigid connection material; 36, insulating material; 37, second conductor; 38, second flow channel; 39, elastic conductor; 40, groove; 41, mine slag discharge transportation system; 42, explosion-proof computer; 43; pressure wind monitoring system; , drill bit body; 53, third flow channel; 54, chassis; 55, power unit; 56, drill stabilization mechanism; 57, attitude adjustment mechanism; 58, main engine;

Detailed ways

The following is a further description of the layout structure of the deep hole pre-splitting blasting in the excavation working face of the present invention in conjunction with the embodiments.

In the following, the inside of the hole, the bottom of the hole and the opening of the hole all refer to different positions of the drilled hole, and the blast hole also refers to the drilled hole.

The blast hole 9 is a linear hole perpendicular to the mining face and nearly horizontal, and the offset is not greater than 1m per 100m. Deviation is unavoidable in a long distance, that is, the actual spatial position of the drilled hole deviates from the designed spatial position, especially in an overly complex structure, due to the anisotropy of the rock, the tilting moment at the drill bit will cause the thick-diameter drilling tool to tilt, resulting in hole inclination; The specific impacts include: 1. The position of the fault plane is inaccurate: when the drill hole deviates, the position of the fault plane of the pre-splitting hole will no longer be accurate, and the blasting effect of the expected design cannot be achieved. This can lead to insufficient cracking force on the fault plane, and eventually the rock after the explosion fails to form the expected cracks. 2. Waste of explosion energy: Pre-splitting blasting needs to be carefully designed and calculated to ensure that the explosion energy is spread evenly enough to form expected fault cracks. When the borehole is deflected, due to energy fluctuations, blast energy is wasted on unnecessary areas instead of forming the intended fractures. 3. Increased safety risks: Pre-splitting blasting operations require high-precision drilling operations, usually in high-risk working environments. If the borehole deviates, the explosion energy will be spread randomly, which may cause safety risks to the surrounding geological environment or personnel. Therefore the present invention has adopted precision drilling device to carry out deep hole drilling.

As shown in Fig. 1 and Fig. 2, an uncoupled continuous charge structure is adopted for the layout structure of a deep hole pre-splitting blasting in the mining face; the blasting holes are arranged in an equilateral triangle, and the hole spacing X, row spacing Y, row number h, and column number a meet the following requirements:

Expansion radius of crack according to loose burst

In the formula: r _t — crack extension radius;

P _r —peak value of initial radial stress of stress wave,

ν—Poisson's ratio; obtained by geological exploration, range 0.2-0.3, 0.28 in the embodiment;

α—stress wave attenuation value, calculated from Poisson’s ratio 2-ν/(1-ν)=1.61;

D—explosive detonation velocity, 3800m/s-4500m/s is provided by the explosive manufacturer, and embodiment gets 4200m/s;

ρ ₀ —explosive density, 1050kg/m ³ -1250kg/m ³ provided by the explosive manufacturer, 1100kg is used in the example

/m ³ ;

r _c —radius of drug roll=0.063/2=0.0315m;

r _b — blast hole radius, the blast hole diameter is designed to be Φ94mm, = 0.094/2 = 0.047m;

S _t — rock mass tensile strength, obtained by geological exploration, converted to pa during calculation, 9MPa in the embodiment;

n—coefficient of pressure increase, range 8-9, embodiment takes 10;

Calculation results according to the embodiment: r _t =0.79m; the theoretical value of crack expansion hole distance is equal to

2r _t -r _b = 1.54m;

Excavation face width A, height H,

Then a=ROUNDUP(A/(2r _t -r _b ),0), that is, A/(2r _t -r _b ) is rounded up, and the hole distance X=A/a

h=ROUNDUP((H/(2r _t -r _b )),0), that is, H/(2r _t -r _b ) is rounded up, row spacing Y=H/h;

Establish a Cartesian coordinate system with point F (0,0) on the structural section as the starting point of the X-axis and Y-axis, and drill holes at [(2m+0.5)X, (2n+0.5)Y], [(k*X, (2t-0.5)Y)], m=0,1,2,3...,

n=0,1,2,3...,k=1,2,3,...,t=1,2,3,...;

(2m+0.5)X<A, (2n+0.5)Y<H, k*X<A, (2t-0.5)Y<H;

The hole depth is the sum of the distance L from the working face to the structure and the length B of the structure; L is at least the first coal-rock transition in the working face, and B is the first coal-rock transition and the second coal-rock transition. The radius of the charge roll is exactly the radius of the shell explosive.

As shown in Fig. 3 and Fig. 4, the uncoupled charge structure includes a cylinder explosion-proof flame arrester 18, a cylinder explosive 19, a detonating charge package 20 and an electric detonator 21, and the cylinder explosion-proof flame arrester 18 is arranged at the bottom of the hole; the cylinder explosive 19 is connected to the length of the structure 67 and pushed into the hole and is adjacent to the cylinder explosion-proof flame arrester 18; two detonating powder packages 20 are loaded into the rear of the cylinder explosive 19, and each detonating powder package 20 is connected in parallel to two pieces of electric lightning Pipe 21; The whole section is laid with a detonating cord 22 inside the tube explosive 19; The detonating cord 22 grows out of the outer end of the detonating charge package 20; The electric detonator 21 connects the lead out of the hole, and the hole is sealed outside the hole.

In this embodiment, the positions of the blast holes are arranged in a triangular shape. The diameter of the blast hole is 94mm, and the outer diameter of the explosive 19 is 45mm-70mm;

The large-diameter blasting hole and uncoupled continuous charge structure are used, and the barrel explosive 19 is connected to the length of the structure 67 and then sent into the blasting hole. The structure is simple and the explosive is conveniently placed in the deep hole. Two electric detonators 21 are used to detonate the detonating charge 20, which can ensure the complete detonation of the detonating charge 20. The detonating cord 22 increases the detonation speed of the explosive, reduces the probability of rejection, and ensures safety and stability. The shell explosive 19 includes a core 49 and a shell 48 wrapped outside the core 49. The two ends of the shell 48 are respectively provided with connectors, and the connectors at both ends are respectively provided with internal and external threads that can engage with each other, so that the shell explosive 19 can be connected one by one, maintain the overall continuity of the multi-section core 49, realize the uniform distribution of the explosive in the direction of the blasting hole, ensure the balance and stability of the blasting, and improve the charging efficiency.

The quilt tube 48 is made of flame suppressant, and the internal flame extinguisher is mainly organic salts; the flame extinguisher in the tube 48 and the flame arrester of the tube 48 can prevent the chemical reaction between the combustible components in the explosive and oxygen, and can increase the ignition temperature of the combustible gas at the same time, so that the combustible gas is not easy to be ignited. Utilize its resistance and heat absorption to reduce explosion flame and flame duration, thereby reducing the possibility of explosive gas explosion and increasing safety redundancy. In the present embodiment, the length of each section of the explosive 19 is 800mm-900mm. If the drug core 49 is too short, more connections are needed to increase the workload, and if the drug core 49 is too long, the drug core 49 may not be loaded. Because the common length of the drill pipe used for drilling is 1000-3000mm long, according to its bending resistance, choosing the length of 800mm-900mm of the barrel explosive 19 can ensure that the charge core 49 can be packed and reduce the number of connections.

In order to ensure the effect of pre-splitting blasting, the pre-splitting blasting device of this scheme adopts an uncoupled continuous charge structure, and a certain gap is left between the explosive 19 in the cylinder and the radial direction of the blasting hole. When the explosion gas expands and the detonation wave transmits its pressure to the hole wall rock through the air medium, it can buffer the explosion shock wave, which not only weakens the initial pressure peak acting on the blast hole, but also makes the pressure evenly distributed and prolongs the action time of the explosion gas, which is conducive to improving the blasting effect and making full use of the energy of the explosive. Explosive gas expansion can increase the generation and expansion of cracks in the coal body, which is beneficial to reduce the stress concentration in the coal body and the stability of the stope. By drilling a large-diameter deep blast hole and loading a large-diameter jacket explosive 19, the loosening depth of a single blast can be increased, and the combined total effect of the shock wave generated by the explosive explosion, the action of the stress wave in the medium and the static action of the explosive gas expansion can be used to break the rock around the blast hole without throwing. The effect of increasing rock fissures in the mining face 66 can reduce equipment loss, improve the efficiency of fully mechanized mining, and reduce production costs. If the dust is too large, improve the occupational health protection of employees.

Electric detonator 21 is instantaneous power detonator 21 or millisecond electric detonator 21 in the same segment; Because in deep hole blasting, when the sensitivity of the explosive is low, the electric detonator 21 cannot be directly detonated, and the detonating charge 20 needs to be used for detonation, and the detonating charge 20 is detonated by the electric detonator 21 . The electric detonator 21 is the millisecond electric detonator 21 that is allowed in the coal mine of the same section. Two electric detonators 21 of the same section can guarantee the detonation at the same time, so that the detonation of the detonating powder package 20 is complete, so that the detonating powder package 20 can fully release the explosion energy, and the relative value of the average released energy is improved. The detonating cord 22 is detonated by the energy generated by the surrounding when the detonating powder package 20 is instantly decomposed. Exploding multi-section quilt tube explosives 19.

The foot line outside of electric detonator 21 is provided with foot line sheath tube 50, and electric detonator 21 connects wires to lead outside the orifice, and the hole sealing material 46 is blocked outside the orifice. Electric detonator 21 leg wires entangle primer pack 20, and leg wires are twisted into short circuit, avoid static electricity or stray current to accidentally detonate electric detonator 21, and detonating cord 22 exceeds primer pack 20 outer end 1m-2m.

In this embodiment, the wire sheath tube 50 makes the wires of the electric detonator 21 suspended in the air without contacting the conductor, and is used to protect the electric detonator 21 and prevent the circuit from being damaged during backfilling. After the filling of the blast hole is completed, the electric detonator 21 wires used for detonating each blast hole are connected in series to the blast bus 45 and the detonator 47. The blast bus 45 requires good insulation and is hung in the air.

In other embodiments, a centering ring is set at the connection between the quilt cylinders 48. The centering ring can allow the quilt cylinder explosive 19 to be located in the middle of the blast hole, and the uncoupled charge forms a certain volume of annular gap between the quilt cylinder explosive 19 and the blast hole wall, which can effectively reduce the initial pressure of the detonation wave, protect the integrity of the hole wall and avoid excessive crushing of the surrounding rock mass, prolong the action time of the road blasting stress wave and detonation gas, and facilitate the expansion of the pre-crack.

It also includes a drum traction rope 44, which is connected to the explosion-proof flame arrester 18 of the drum, and the length of the drum traction rope 44 exceeds the depth of the blast hole, that is, it is greater than the length of L+B. The drum pull rope 44 is connected to the explosion-proof flame arrester 18 of the drum and pushed to the bottom of the hole; when the explosive is stuck in the hole by the drum 48 and cannot continue to enter the deep part of the borehole, the drum 48 can be pulled out by the drum 48 using the pulling rope.

The hole is sealed by a sealing material 46 or a hole sealing device, and the sealing material 46 is made of yellow mud, water gun putty, clay gun putty or non-combustible and plastic material. In this embodiment, the sealing material 46 is water taphole mud, and the water foam mud becomes gas under the high temperature of the explosive, which can further enhance the gas wedge fracturing effect. In other embodiments, a hole sealer may also be used for hole sealing.

This scheme adopts an uncoupled continuous charge structure, and there is a certain gap between the explosive 19 and the radial direction of the blasting hole. When the explosion gas expands and the detonation wave transmits its pressure to the hole wall rock through the air medium, it can buffer the explosion shock wave, which not only weakens the initial pressure peak acting on the blast hole, but also makes the pressure evenly distributed and prolongs the action time of the explosion gas, which is conducive to improving the blasting effect and making full use of the energy of the explosive. The energy generated by blasting can increase the generation and expansion of cracks in the coal body, which is beneficial to reduce the stress concentration in the coal body. After the filling of the blasting holes is completed, the blasting wires of each blasting hole are connected in series to the blasting busbar 45, and the blasting network blasting is adopted in parallel connection inside the hole and series connection outside the hole, which can reduce the number of blasting. Combined with ANSYS/LS-DYNA finite element dynamic simulation analysis software, the optimal blasting parameters such as uncoupled charge coefficient, blast hole depth, charge amount, and blast hole spacing can be determined. By drilling a large-diameter deep blast hole and loading a large-diameter jacket explosive 19, the loosening depth of a single blast can be increased. Using the combined effect of the shock wave generated by the explosive explosion, the action of the stress wave in the medium, and the static effect of the explosive gas expansion, the rock around the blast hole is broken without throwing. Controlled blasting can thus achieve the effect of increasing rock cracks in the mining face 66, reducing equipment loss, improving fully mechanized mining efficiency, and reducing production costs, and realizing safe and rapid advancement of the working face 66.

As shown in Figures 5 and 6, the precision drilling device for deep hole pre-splitting blasting through the structure of the mining working face includes a directional drilling machine 1, an electronic water braid 2, a cable drill rod 3, a bottom-hole screw drilling tool 4, a directional drill bit 5, a measuring-while-drilling probe 6, and a power source 7 for driving the hole-bottom screw drilling tool 4; The tool 4 is connected to the drill bit transmission; the measuring-while-drilling probe 6 is set on the cable drill pipe 3; the outlet 23 of the electronic water braid 2 is connected to the rear end of the cable drill pipe 3, and the inlet 26 is connected to the water supply pipe 8; one end of the air blower is connected to the electronic water braid 2, and the other end is connected to the explosion-proof air compressor 10; the drilling depth is the sum of the distance from the working face 66 to the structure 67 and the length of the structure 67; The position and inclination angle of the drill pipe can be monitored in real time through the measurement while drilling, and the drilling direction can be adjusted through the directional drill bit, thereby improving the accuracy and high precision of the drilling, and helping to improve the effect of pre-splitting blasting.

As shown in Figure 6, the directional drilling rig 1 includes a chassis 54, a main engine 58, a power unit 55, a drilling stabilization mechanism 56, and an attitude adjustment mechanism 57. The attitude adjustment mechanism 57 is connected to the chassis 54, and the main engine 58 is installed on the attitude adjustment mechanism 57. The main engine 58 includes a rotary feed mechanism; the power unit 55 includes an explosion-proof motor and a hydraulic pump, which are used to output hydraulic oil for the operation of the drilling rig and various mechanisms. The chassis 54 is driven by a hydraulic motor and is used for the automatic driving of the directional drilling machine 1 . The power unit 55 includes an explosion-proof motor and a hydraulic pump, which are used to output hydraulic oil for the operation of various mechanisms of the drilling rig.

Drill stabilizing mechanism 56 is a hydraulic cylinder arranged upwards and downwards on chassis 54. Power unit 55 provides hydraulic power to extend the hydraulic cylinder for pressing against the roadway ground and roof, and stabilizes the directional drilling machine 1 and the drill pipe during drilling.

The rotary feed mechanism includes a hydraulic motor, a reduction box, and a feed cylinder. The feed cylinder is an actuator for reciprocating linear motion in the hydraulic system. After the drive shaft of the hydraulic motor passes through the reduction box to adjust the speed, it drives the feed cylinder to reciprocate and linear motion, which is used to control the direction of deflection during drilling and bottom deflection. In this embodiment, the rotary feeding mechanism may be of the type described in CN202110264181.9.

The attitude adjustment mechanism 57 includes a lifting seat 60, a pitching rotary assembly 59 and a lifting oil cylinder 62 installed on the chassis 54. The lifting seat 60 is fixedly installed on the moving part of the lifting oil cylinder 62;

The lifting base 60 is fixedly installed on the moving part of the lifting cylinder 62, and the lifting cylinder 62 drives the lifting base 60 to move up and down along the height direction of the chassis 54, and then drives the pitching and slewing assembly and the drilling rig main frame 58 to lift relative to the chassis 54, so as to realize the adjustment of the drilling height of the drilling rig main frame 58; the attitude adjustment mechanism 57 is used for the drilling height and drilling pitch angle of the main frame 58, and cooperates with the drilling program of the drilling rig to realize the automatic operation of positioning drilling.

The cable-through drill pipe 3 is also called the directional drill pipe. The cable-through device inside the drill pipe is used for the transmission of measurement data while drilling. It is the signal transmission device between the inclinometer unit at the bottom of the hole and the inclinometer equipment at the hole opening. It is an important supporting drilling tool to ensure the smooth implementation of directional drilling. In this embodiment, the model of the cable drill pipe 3 is but not limited to Yikuang YKDRILL cable drill pipe 3 .

The drilling operation needs to strictly follow the blasting design requirements, and master the hole position, hole depth and angle. The drilling trajectory data, hole depth record data, angle data, etc. of the measuring point can be fed back to the explosion-proof computer 42 outside the hole through the cable drill pipe 3 through the measurement-while-drilling probe 6 . The water braid is used to connect the drill rig and the joint of the water pipe. During the drilling process of the rig and the coal formation, the pressurized water in the water supply pipe 8 enters the cable drill pipe 3 from the electronic water braid 2, and the water is sprayed into the drill hole from the drill bit through the cable drill pipe 3 to reduce dust. If connected to high-pressure water, hydraulic punching can also be performed. After the drilling rig is pulled out, the air blower utilizes the compressed air produced by the explosion-proof air compressor 10 to blow off the residue in the hole, so as to ensure the smooth charging of the follow-up.

As shown in Figure 7, the blowout prevention separation device 101 includes a dust collection cover 11 and a gas-water slag separation device installed at the rear end orifice of the cable drill pipe 3. The gas collection cover is connected with an exhaust port 12, a drain port 13 and a slag discharge port 14, and a filter device 15 is arranged between the through hole 63 of the gas collection cover, the exhaust port 12, and the drain port 13. The exhaust port 12 is connected with the mine gas extraction pipe 16; the drain port 13 is connected with the mine pool 17; The slag discharge transportation system 41 is connected.

Since the drill pipe is connected to the air blower, the air blower sends air to the hole to blow off the residue, and the electronic water braid 2 sends water to the hole to reduce dust and punch holes; therefore, residue, dust, gas, and waste water will be sprayed out from the orifice. The dust collection cover 11 can play a role in gathering the residue and dust and prevent them from being sprayed out in all directions. The collected residue enters the mine slag discharge transportation system 41 through the slag discharge port 14 and is discharged; the gas gas is filtered through the filter device 15 to dust, and is discharged into the gas extraction pipe through the exhaust port 12, and the dust falls into the slag discharge port 14; In this embodiment, the filter device 15 is a metal filter screen of corresponding mesh.

As shown in Figure 8, the electronic water braid 2 includes a fixed end 24 and a rotating end 25, the fixed end 24 is provided with an inlet 26 and a communication port 27, the fixed end 24 and the rotating end 25 have a first flow channel 28 through it, the fixed end 24 and the rotating end 25 are rotatably connected by a bearing 29, an insulating layer 30 is provided inside the fixed end 24 and the rotating end 25, and a first conductor 31 is provided inside the insulating layer 30, and the first conductor 31 is connected to the communication port 27, and the communication port 27 is connected to an explosion-proof computer 42. One end of the electronic water braid 2 is connected to the water pipe or air pipe, and the other end is connected to the cable drill pipe 3 through threads. It is a transition device for the external flushing fluid to enter the drill pipe and transmit signals.

As shown in Figure 9, the cable drill rod 3 includes a rod body 32, the two ends of the rod body 32 are provided with internal threads 33 and external threads 34 that engage with each other, the rod body 32 is provided with a rigid connecting material 35, the rigid connecting material 35 is filled with an insulating material 36, the insulating material 36 is provided with a second conductor 37, and there is a second flow channel 38 connected between the rigid connecting material 35 and the inner wall of the rod body 32. One end of the second conductor 37 is an elastic conductor 39, and the other end is provided with a matching groove 40 for the elastic material; The outer diameter of the body 32 is φ73 mm, and the length is 1000-3000 mm; the outside of the rod body 32 is also provided with a spiral groove 51 . The measurement-while-drilling probe 6 includes a magnetic azimuth sensor and an inclination sensor;

The inlet 26 of the fixed end 24 is communicated with the mine water supply pipe 8, and the inlet 26 can also input mud and compressed air as the power of the motor at the bottom of the hole, and can also discharge drilling cuttings in the hole out of the hole. The rotating end 25 communicates with the rear end of the cable drill rod 3 ; the first flow channel 28 of the electronic water braid 2 communicates with the second flow channel 38 of the cable drill rod 3 . The insulating layer 30 is used to prevent water from communicating with the first conductor 31, and the first conductor 31 is used to be connected with the elastic conductor 39 of the cable drill rod 3; the elastic conductor 39 is connected with the second conductor 37, the conductor shell of the drill rod, and the magnetic azimuth sensor and the inclination sensor are connected with the conductor shell of the drill rod, the second conductor 37, and are used for signal transmission while drilling.

As shown in Figure 10, the directional drill 5 includes a drill body 52, the outer diameter of the rear end is φ73mm, and the internal thread 33 that is first engaged with the external thread 34 of the drill pipe is provided. The outer diameter of the front end is φ94mm. Water, input mud, compressed air, and at the same time, drill cuttings in the hole are discharged backward.

The screw drilling tool 4 at the bottom of the hole is specifically a hydraulic screw motor or a pneumatic screw motor with an elbow; during the working process of the screw drilling tool 4 at the bottom of the hole, the drill bit rotates to break the rock, but the whole drilling tool does not rotate; by replacing the directional bend joint body or the outer tube of the lower universal joint, the screw drilling tool 4 at the bottom of the hole is bent to adjust the orientation.

The usage method of this program is:

Step S1: geological exploration: obtain rock mass tensile strength and Poisson's ratio, and parameters such as width, height, thickness of structure;

Step S2: Directional drilling:

The directional drilling machine adopts the φ73-94 cable drill pipe (φ94 is the outer diameter of the cutting edge, and the φ73 refers to the connection with the φ73 drill pipe) drill bit for directional drilling;

Step S3: inspecting holes, probing holes, clearing holes;

The hole inspection uses the ZKXG100 mine trajectory detection device to verify the angle, length, trajectory and other parameters of the blast hole and record the verification results. In order to ensure smooth charging, when the drilling rig is pulled out, blow off the residue in the hole with compressed air, and use the connecting rod to probe the blast hole and record the drilling depth;

Step S4: charging;

The charge adopts the core of the tube, the length of each section is 800mm or 900mm, the outer diameter is φ63, and the total charge length is B; the details are determined according to the explosive specifications used by each mine. First put into the explosion-proof flame arrester of the quilt tube, and then gradually send the cores of the quilt tube into the hole one by one. When charging, every two quilt tubes are connected by connectors, and after multiple quilt tubes are connected by connectors, the overall continuity of the multi-section drug package can be maintained. Probing the hole before charging can effectively avoid the problem of stuck holes; at the same time, in case of stuck holes, you can also take corresponding preventive measures. Generally, before charging the explosives, pierce the end of the flame arrester at the innermost end of the barrel and thread it into a high-strength traction rope. The length of the traction rope exceeds the drilling depth.

Step S5: plugging;

Use special high-viscosity adhesive sealing material or high-pressure special sealer for sealing;

Step S6: detonate network connection:

After the filling of each blast hole is completed, each conductor is connected in series to the bus network. The blasting bus must be well insulated and hung in the air. The blasting busbar should be 300m long to meet the requirements of long-distance blasting, and there is no joint in the middle.

Step S7: detonation network resistance detection

During the blockage process, the resistance is measured along with it, and if any abnormality is found, it should be dealt with in time;

Step S8: implement vigilance;

Step S9: detonate; adopt the MFB200 type detonator to detonate, measure the resistance situation in a safe place before detonating, and detonate after no exception;

Step S10: post-explosion inspection.

The following are examples of the implementation of this program:

XX Coal Industry XX Excavation Face Deep Hole Pre-splitting Blasting Operation

The diameter of the blasting hole is φ94mm, and the hole depth is designed to be 25m (if the coal-rock junction is found during the perforation process before reaching the designed hole depth, the drilling shall be stopped immediately, and the hole depth shall be selected according to the actual hole depth).

In order to control the blasting vibration, 2, 3, 4 coal mine permissible electric detonators are used to detonate. The connection method is parallel connection inside the hole and series connection outside the hole.

The effect after the explosion is as follows:

1. There are a few cracks in the orifice during post-explosion inspection. After the blasting, mine personnel tracked and observed during the excavation period that there was no obvious blasting effect in the mud sealing section, and there were obvious cracks in the blasting section, and the rock was easy to cut during the excavation process.

2. Reduced loss of picks: The loss of picks is greatly reduced. When the coal cutter passes through the whole rock section, the rocks are peeled off in small pieces, the consumption rate of picks is reduced by about 40%, and the downtime for manual replacement of picks is reduced.

3. Improved coal cutting efficiency: The daily footage of the working face can be increased by 30%, improving the coal mining efficiency.

4. Reduce safety risks: After the working face enters the whole rock section, there is basically no need for shallow hole blasting operations, which greatly reduces safety risks. Moreover, during the construction process of deep hole pre-splitting blasting, there is no blind shot or punching phenomenon, and no damage is caused to the top and bottom plate of the construction working face, and the blasting vibration is controlled within the safe range.

5. Reduced dust concentration: After passing through the deep hole blasting, the coal cutter does not need to be forced to advance after entering the whole rock section, which greatly reduces the dust and provides protection for the occupational health of employees. The method of deep hole pre-splitting loosening blasting is used to weaken the hard rock that will be encountered during the advancing process of the mining face, that is, pre-splitting loosening blasting is carried out on the rock mass at a certain distance in the advanced working face to ensure that the fully-mechanized mining face can pass through the blasting area smoothly.

Claims (10)

1. The over-structured deep hole pre-splitting blasting layout structure of the mining working face is characterized by adopting a uncoupled continuous charging structure; the blasting Kong Jian is arranged in a regular triangle, and the hole pitch X, the row pitch Y, the row number h and the column number a meet the following requirements:

according to the expansion radius of the loose blasting crack

Wherein: r is (r) _t -fracture expansion radius;

P _r the stress wave initial radial stress peak,

v-poisson ratio; alpha-stress wave attenuation value; d, explosive explosion speed; ρ ₀ -explosive density;

r _c -cartridge radius; r is (r) _b -blasthole radius; s is S _t -tensile strength of the rock mass; n-pressure increase coefficient; the width A and the height H of the mining working face,

a=roundup (a/(2 r) _t -r _b ) 0), i.e. A/(2 r) _t -r _b ) Rounding up, pitch x=a/a

h＝ROUNDUP((H/(2r _t -r _b ) 0), i.e. H/(2 r) _t -r _b ) Rounding up, row spacing y=h/H;

establishing rectangular coordinate system with F point (0, 0) on the structural section as the starting point of X axis and Y axis, respectively constructing drilling holes at [ (2m+0.5) X, (2n+0.5) Y ], [ (k X, (2 t-0.5) Y) ] positions, m=0, 1,2,3 … …,

n＝0,1,2,3……，k＝1,2,3,……，t＝1,2,3,……；

(2m+0.5)X<A，(2n+0.5)Y<H,k*X<A，(2t-0.5)Y<H；

the depth of the hole is the sum of the working face-to-construction distance L and the construction length B; l is at least first coal and rock connection stop of working face drilling, and B is first coal and rock connection stop and second coal and rock connection stop.

2. The mining face over-construction deep hole pre-split blast layout structure according to claim 1, characterized in that the uncoupled charge structure comprises a cartridge explosion-proof flame arrester (18), a cartridge explosive (19), an initiating explosive (20) and an electric detonator (21); the cylinder explosion-proof flame arrester (18) is arranged at the inner end of the explosion hole (9); the explosive (19) is pushed to the blast hole (9) and is close to the explosion-proof flame arrester (18) of the cartridge after being connected to the construction length B section by section; 2 primary explosive charges (20) are filled in the rear part of the blocked explosive (19), and each primary explosive charge (20) is connected with 2 electric detonators (21) in parallel; the inner part of the full-section tube-like explosive (19) is laid with a detonating cord (22); the detonating cord (22) grows out of the outer end of the initiating explosive (20); the electric detonator (21) is connected with a lead to be led out of the blast hole (9), and the outside of the blast hole (9) is subjected to hole sealing.

3. The mining face over-construction deep hole pre-splitting blasting layout structure according to claim 2, wherein the blastholes (9) have a diameter of 94mm and the outer diameter of the tube explosive (19) is 45mm to 70mm.

4. A face over-formation deep hole pre-split blast layout structure according to claim 3, characterized in that the outer diameter of the drum explosive (19) is 63mm.

5. A face over-construction deep hole pre-split blast layout structure according to any of claims 2 to 4, characterized in that each section of the tube explosive (19) has a length of 800-900 mm.

6. The mining face over-construction deep hole pre-splitting blasting layout structure according to any one of claims 2 to 4, wherein the passive explosive (19) comprises a explosive core (49) and a passive tube (48) wrapped on the explosive core (49), connectors are respectively arranged at two ends of the passive tube (48), and internal and external threads capable of being meshed with each other are respectively arranged on the connectors at two ends.

7. The mining face over-construction deep hole pre-splitting blasting layout structure according to claim 5, wherein the passive explosive (19) comprises a explosive core (49) and a passive barrel (48) wrapped on the explosive core (49), connectors are respectively arranged at two ends of the passive barrel (48), and inner and outer threads capable of being meshed with each other are respectively arranged on the connectors at two ends.

8. The mining face over-construction deep hole pre-split blasting layout structure of claim 2,3, 4 or 7, wherein the electric detonator (21) is a transient electric detonator or a same-segment millisecond electric detonator.

9. The mining face over-construction deep hole pre-split blasting layout structure according to claim 5, characterized in that the electric detonator (21) is an instantaneous electric detonator or a same-segment millisecond electric detonator.

10. The mining face over-construction deep hole pre-split blasting layout structure according to claim 6, characterized in that the electric detonator (21) is an instantaneous electric detonator or a same-segment millisecond electric detonator.