CN111335892A - Strong-impact coal seam pressure relief prevention and control method - Google Patents
Strong-impact coal seam pressure relief prevention and control method Download PDFInfo
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- CN111335892A CN111335892A CN201911387917.0A CN201911387917A CN111335892A CN 111335892 A CN111335892 A CN 111335892A CN 201911387917 A CN201911387917 A CN 201911387917A CN 111335892 A CN111335892 A CN 111335892A
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Abstract
The invention relates to the technical field of strong impact coal seam prevention and control, and provides a strong impact coal seam pressure relief prevention and control method, which comprises head-on advanced drilling pressure relief, two-side covering drilling pressure relief and bottom breaking pressure relief when meeting bottom coal explosion; head-on advance drilling release includes: constructing three pressure relief drill holes at the head of the driving face; two sides cover formula drilling release includes: respectively drilling pressure relief drill holes on two sides of the roadway, wherein the distance between two adjacent holes is not more than 2 m; the bottom coal explosion breaking bottom pressure relief includes: drilling blast holes on the tunnel bottom plate, filling explosive to blast, promoting the stress peak value in the bottom plate to transfer to the deep part, and eliminating the impact of the bottom plate. Therefore, the invention adopts the modes of head-on advanced drilling pressure relief, two-side covering drilling pressure relief and bottom breaking pressure relief in case of bottom coal explosion on the tunneling working face. The pressure relief drill holes are drilled in the roadway, so that the stress around the roadway is effectively reduced. The stress distribution is moved to the deep part of the coal bed, the stability of the tunneling working face is effectively guaranteed, and the safe tunneling of the roadway is guaranteed.
Description
Technical Field
The invention belongs to the technical field of prevention and control of a strong-impact coal seam, and particularly relates to a pressure relief prevention and control method of the strong-impact coal seam.
Background
Rock burst (also called as "rock burst"), which is a typical dynamic disaster phenomenon in mines, mainly manifested by the sudden and violent release of elastic strain energy accumulated in coal rock mass, and the sudden and violent destructiveness thereof poses a great threat to mine safety.
With the increase of coal mining depth and the gradual expansion of mining range, the rock burst hazard of coal mines in China is becoming more and more serious. According to incomplete statistics, 253 pairs of rock burst mines which are mined in China are distributed in 26 provinces, cities and autonomous regions.
The rock burst is the phenomenon that coal and rock mass around a roadway and a stope release deformation energy under certain high stress condition in the coal mining process, and the generated coal and rock mass is suddenly damaged, collapsed or thrown out, and is accompanied with huge sound and rock mass vibration, so that support breakage, rib caving, roadway blockage and casualties are often caused. Rock burst can also cause other mine disasters including gas and coal dust explosion, fire, and ventilation system interference, and can also cause damage similar to natural earthquakes in severe cases, causing ground vibration and building destruction, and the like. Therefore, rock burst is one of the major disasters in coal mines.
The rock burst is characterized in that: burstiness, destructiveness, and complexity.
Burstiness: there is generally no apparent precursor before occurrence, and the impact process is short, lasting from a few seconds to tens of seconds. Generally, the method is characterized by coal explosion (coal wall explosion and small block ejection), shallow impact (which is generated within the range of 2-6 m of the coal wall and has large destructiveness) and deep impact (which is generated in the deep part of the coal body and has different destructiveness if sound like smoldering). Most commonly, the coal seam is impacted, and a roof impact and a floor impact exist, and rock burst happens to a few mines. In coal bed impact, most of the coal is thrown out, and a few of the coal is moved integrally by dozens of square meters, and is accompanied by huge sound, rock mass vibration and shock waves.
Destructive performance: the coal wall caving, the sinking of the top plate, the bottom bulging, the breakage of the support, the blockage of the roadway and the casualties are often caused.
Complexity: on the natural geological condition, the mining depth of various coals except lignite is 200-1000 m, the geological structure is simple to complex, the thickness of a coal bed is from a thin layer to an extra thick layer, the inclination angle is from horizontal to steep, and the top plate comprises sandstone, limestone, oil shale and the like, and the overburdened pressure is generated; in the aspects of technical conditions such as a coal mining method, a coal mining process and the like, no matter water mining, blasting mining, general mining or fully mechanized mining is adopted for goaf treatment, a total caving method or a hydraulic filling method is adopted, and the goaf is longwall, shortwall, room-pillar mining or pillar mining, the overburst ground pressure is generated, and only the number of times of impact of the longwall mining method without coal pillars is small.
According to the stress state of a raw rock (coal) body, the rock burst is divided into: gravity stress type rock burst. The rock burst caused under the condition of no or only little influence of construction stress is mainly influenced by gravity. Such as the rock burst in the mining areas of jujube banker, smoothie, kao 28390. And constructing stress type rock burst. Rock burst, which is mainly caused by the action of construction stresses, which far exceed the self-weight stresses of the rock formations, such as occur in the northern Tibet Ministry and Tianchi coal mines. Medium type or gravity-structure type rock burst. The rock burst is mainly caused by the combined action of gravity and constructional stress.
The rock burst is classified into:
ejection: some single fragments are shot from coal or rock mass under high stress and are accompanied by strong sound, which belongs to the micro-impact phenomenon.
Mine earthquake: the coal or rock is not thrown out to the mined space, but only has the phenomenon of strip or collapse, but generates obvious vibration, huge sound and sometimes coal dust. Weaker mine earthquakes are called microseisms, also called coal cannons.
Weak impact: the coal or rock is thrown out to the mined space, but the coal or rock is not very destructive and has no damage to supports, machines and equipment basically; the surrounding rocks generate vibration, the magnitude of the vibration is generally below 2.2, and the vibration is accompanied by loud sound; coal dust is generated, and a large amount of gas possibly flows out in a gas coal layer.
Strong impact: the coal throwing amount is more than 50t, and the earthquake magnitude is more than 2-grade rock burst.
Which is a great danger of strong impacts. Can lead to the rapid crushing of partial coal or rock, a large amount of the coal or rock is thrown out to the mined space, the breakage of a bracket, the movement of equipment and the vibration of surrounding rocks occur, the vibration level is more than 2.3, and the large sound is accompanied, so a large amount of coal dust is formed and shock waves are generated.
In view of the above, the prior art is obviously inconvenient and disadvantageous in practical use, and needs to be improved.
Disclosure of Invention
Aiming at the defects, the invention aims to provide a strong impact coal seam pressure relief control method, which adopts a head-on advanced drilling pressure relief mode, a two-side covering type drilling pressure relief mode and a bottom breaking pressure relief mode when meeting bottom coal explosion on a tunneling working face. The pressure relief drill holes are drilled in the roadway, so that the stress around the roadway is effectively reduced. The stress distribution is moved to the deep part of the coal bed, the stability of the tunneling working face is effectively guaranteed, and the safe tunneling of the roadway is guaranteed.
In order to achieve the purpose, the invention provides a strong impact coal seam pressure relief control method, which comprises the steps of pressure relief of a tunneling working face, wherein the pressure relief is used for ensuring the safe tunneling of a roadway;
the pressure relief of the tunneling working face comprises head-on advanced drilling pressure relief, two-side covering type drilling pressure relief and bottom breaking pressure relief in case of bottom coal explosion;
head-on advance drilling release includes: constructing three pressure relief drill holes at the head of the driving face; the pressure relief drill holes are arranged at the positions which are not less than 0.5m away from the roadway bottom plate;
the diameter of the pressure relief drill hole is 150mm, the depth of the pressure relief drill hole is 15m, and the pressure is cyclically relieved once every 5m of tunneling, so that a pressure relief protective belt with the tunneling head not less than 10m is kept;
the two sides cover formula drilling release includes: respectively drilling pressure relief drill holes on two sides of the roadway, wherein the distance between two adjacent holes is not more than 2 m; the diameter of the pressure relief drill hole is 150mm, the hole depth is 20m, and the pressure relief drill hole is arranged at a position which is not less than 0.5m away from the roadway bottom plate; the maximum distance between the pressure relief drill holes of the two sides and the head is not more than 8 m;
the bottom coal explosion breaking bottom pressure relief includes: drilling blast holes on a roadway bottom plate, filling explosives for blasting, and destroying the bottom plate structure, so that pressure relief of drilling surrounding rocks and transfer of a horizontal stress peak value in the bottom plate to the deep part of the bottom plate are promoted, and further, bottom plate impact is eliminated.
According to the method for preventing and treating the pressure relief of the strong-impact coal seam, the arrangement positions of the pressure relief drill holes for head-on advanced drilling for pressure relief are as follows: one is arranged at the center of the head, and two sides are respectively arranged at 45 degrees. The heading is one-shift pressure relief two-shift tunneling every day, so that the heading always keeps advancing to a pressure relief protective belt of not less than 10 m.
According to the strong impact coal seam pressure relief control method, when the pressure relief drill hole is drilled to a preset depth due to power abnormity, the following steps are carried out: and (5) alternately constructing at 0.5-1 m positions on two sides of the pressure relief drill hole, and circularly punching to mutually draw out coal powder until the coal powder is drilled to a preset depth.
According to the method for preventing and treating the pressure relief of the high-impact coal seam, the blastholes are arranged at equal intervals downwards along the bottom of the roadway at an angle of 90 degrees, the interval is 0.8m, the explosive is a secondary emulsion explosive, the specification is phi 32mm, × 210mm and 210mm, and each explosive is 0.2 kg.
According to the method for preventing and treating the pressure relief of the strong-impact coal seam, the pulverized coal in blast holes is discharged completely before the explosive is filled; the charging adopts the filling of separated holes; when the hole depth is larger than 1.5m and smaller than 5m, two bundles of 3 blocks are charged; when the hole depth is larger than 5m, three bundles of 3 blocks are filled.
According to the method for preventing and treating the pressure relief of the high-impact coal seam, the blasthole is sealed by using water stemming: the remaining blast hole part outside the water stemming is sealed by clay stemming; when the depth of the blast hole exceeds 2.5m, the length of the sealing mud is not less than 1 m; when the hole depth is more than 5m, the sealing mud length is not less than 1/3 of the hole depth.
According to the method for preventing and treating the pressure relief of the strong-impact coal seam, the pressure relief of the tunneling working face also comprises reinforcing pressure relief; the reinforcement pressure relief comprises the steps of fault encryption pressure relief, pressure relief before opening a roadway, pressure relief before communicating the roadway and pressure relief in a tunneling disturbance area.
According to the method for preventing and treating pressure relief of the strong-impact coal seam, the process of pressure relief by crossing fault encryption comprises the following steps: when the depth of the visible rock is less than 20m, drilling a pressure relief borehole at the side part of the roadway; and the included angle between the construction vertical angle of the pressure relief drilling hole and the coal seam is 0-21 degrees.
According to the method for preventing and treating the pressure relief of the strong-impact coal seam, the pressure relief before the door of the roadway is opened comprises the following steps: constructing pressure relief drill holes 10m inwards in the opening of the door in the roadway opening acute angle area; constructing pressure relief drill holes in the inner 8m of the opening door in the obtuse angle area; and constructing pressure relief drill holes in the range of 10m above and below the center line of the side wall part of the opening side of the roadway at the interval of 1m, the diameter of the drill holes of 110mm and the depth of the drill holes of 20 m.
According to the method for preventing and treating the pressure relief of the strong-impact coal seam, the pressure relief before the tunnel is communicated comprises the following steps: when two tunnels which are tunneled in opposite directions are through 150m, one of the two tunnels is paused to be tunneled;
when the distance is 50m, the coal dust amount of two sides of the roadway must be detected once every day by a drilling cutting method during the tunneling; the inspection holes are constructed by a frame column hand-held pneumatic drilling machine, 1 inspection hole is constructed on each of two sides of the roadway, and the depth of each inspection hole is 20 m.
The invention aims to provide a strong impact coal seam pressure relief control method, which adopts a head-on advanced drilling pressure relief mode, a two-side covering type drilling pressure relief mode and a bottom breaking pressure relief mode when meeting bottom coal explosion on a tunneling working face. The pressure relief drill holes are drilled in the roadway, so that the stress around the roadway is effectively reduced. The stress distribution is moved to the deep part of the coal bed, the stability of the tunneling working face is effectively guaranteed, and the safe tunneling of the roadway is guaranteed.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The above-mentioned directions or position relationships are used for better describing the technical solution, so that the reader can understand that the practical implementation includes but is not limited to the description.
The invention provides a strong impact coal seam pressure relief prevention method, which comprises the steps of carrying out pressure relief on a driving working face; and ensuring the safe tunneling of the roadway.
The pressure relief of the tunneling working face comprises head-on advanced drilling pressure relief, two-side covering type drilling pressure relief and bottom breaking pressure relief in case of bottom coal explosion.
Head-on advance drilling release includes: constructing three pressure relief drill holes at the head of the driving face; the pressure relief drill holes are arranged at the positions which are not less than 0.5m away from the roadway bottom plate;
better, the arrangement position of the pressure relief drill hole of the head-on advanced drilling pressure relief is as follows: one is arranged at the center of the head, and two sides are respectively arranged at 45 degrees. The heading is one-shift pressure relief two-shift tunneling every day, so that the heading always keeps advancing to be not less than 10m of a pressure relief protective belt.
If abnormal power phenomena such as drill sticking, drill suction, coal gun sound, roof sinking and the like do not exist in the drilling process, the head-on pressure relief drilling construction can be carried out to the preset depth, and then normal tunneling can be carried out.
When the pressure relief drill hole is drilled to a preset depth due to power abnormity, the following steps are executed:
and (5) alternately constructing at 0.5-1 m positions on two sides of the pressure relief drill hole, and circularly punching to mutually draw out coal powder until the coal powder is drilled to a preset depth.
Furthermore, as the head of the tunneling working face is influenced by advanced supporting pressure and tunneling disturbance, a stress concentration area is formed in the front of the head, and roof caving and wall caving are easy to happen to the head in the tunneling process, a head-on advanced drilling pressure relief measure is adopted, so that the high-stress area of the head is transferred to the deep part. In order to ensure the head-on construction safety, the diameter of the pressure relief drill hole is 150mm, the depth is 15m, and the pressure is cyclically relieved once every 5m of tunneling, so that the tunneling head-on is kept to be not less than 10m of pressure relief protective belt.
The two sides cover formula drilling release includes: respectively drilling pressure relief drill holes on two sides of the roadway, wherein the distance between two adjacent holes is not more than 2 m; the diameter of the pressure relief drill hole is 150mm, the hole depth is 20m, and the pressure relief drill hole is arranged at a position which is not less than 0.5m away from the roadway bottom plate.
The maximum distance between the two pressure relief drill holes and the head is not more than 8 m; when the distance between the pressure relief drilling hole and the head exceeds the specified distance, the heading must be stopped, and the construction can be carried out after the pressure relief is finished.
If the hole depth is insufficient for the design depth or the pressure is increased when the geological structure changes, measures for encrypting the pressure relief drill hole spacing are taken. Because the pressure relief drilling hole has unqualified angle, obvious drill blocking, drill suction and power display, the one-time powder discharge amount of the pressure relief drilling hole is large, and a circulating drilling method can be adopted when a drill rod is easy to block. The depth of the pressure relief drill hole is less than 20m, and the pressure relief drill hole is re-drilled within 0.5m from the hole to 20 m.
As the coal mine excavation roadway is large in burial depth, most of working faces are buried to a depth of over 1000m, and in order to ensure the safety of excavation roadway in the coal seam with impact hazard, large-diameter drilling is adopted for pressure relief of the excavation roadway side part with impact ground pressure hazard according to the principle of stress three-way chemical transfer. The large-diameter drilling causes structural damage to surrounding rocks at the deep part of the roadway (surrounding rocks near the far end of the drilling hole), a weakening zone is formed, high stress in the surrounding rocks at the periphery of the roadway is caused to transfer to the deep part, so that the surrounding rocks near the periphery of the roadway are in a low stress state, when impact occurs, on one hand, the space of the large-diameter drilling can absorb flushed coal powder, coal body flushing is prevented, on the other hand, a pressure relief area generates a wedge-shaped resistance zone, and disaster occurrence caused by the coal body flushing can also be prevented.
The pressure relief drilling parameters are 150mm in aperture, 20m in depth and 1m in spacing. The large aperture of 150mm is beneficial to discharging more coal dust, and the pressure relief effect is better according to the concept of low density.
Further, the depth of the pressure relief borehole of the present invention is preferably 20 m. According to actual measurement of construction coal dust amount and power display, the stress peak area of the surrounding rock of the roadway is between 12 and 17m, and the effect of selecting a drilling depth of 20m is good; the distance between the drill holes is 1m, the strong impact dangerous area is set, active precaution is carried out in advance, and the purpose of strong pressure relief is achieved.
Faults are usually encountered in the process of tunneling, so that bottom coal is inevitably left. If the thickness of the bottom coal exceeds 1.5m, the bottom is broken to release the pressure. Or if the distance between the bottom coal area and the head-on exceeds 8m, the centralized processing is needed once.
Further, the invention also comprises the step of bottom coal explosion breaking and bottom pressure relief, which comprises the following steps: and drilling blast holes on the bottom plate of the roadway, filling explosives for blasting, and destroying the structure of the bottom plate, so that the pressure relief of the drilling surrounding rock and the transfer of a horizontal stress peak value in the bottom plate to the deep part of the bottom plate are promoted, and the impact of the bottom plate is eliminated.
The typical coal mine bottoming coal cases include: reserving bottom coal, reserving bottom coal when meeting a fault, and tunneling a tunnel through a coal bed to reserve the bottom coal according to design requirements.
Preferably, before blasting, roof and side support are strengthened by anchor rods and anchor cables.
As an embodiment, the blastholes are arranged at equal intervals downwards along the bottom of the roadway at 90 degrees, and the interval is 0.8 m.
The explosive is preferably a two-stage emulsion explosive, the specification is phi 32mm × 210mm, each 0.2 kg. detonator of the explosive uses a millisecond delay electric detonator, each section of delay 25 ms. hole sealing uses a cement cartridge with the specification of phi 36mm × 225mm, the drilled hole is completely sealed by the cement cartridge, the explosive carrier adopts a PVC plastic pipe with the specification of phi 75mm, the use length is determined according to the charge amount, the blasting lead wire adopts a coal mine explosion-proof telephone cable (the same type of cable can also be adopted), and the blasting hole is normally charged when meeting water.
The coal dust in the blast hole is discharged before charging. The charging adopts hole-separating charging. When the hole depth is more than 1.5m and less than 5m, 2 bundles of 6 blocks are charged. When the hole depth is larger than 5m, 3 bundles of 9 blocks are filled with the medicine. Every 3 pieces of explosive are bundled into 1 bundle. PVC plastic pipes are used as explosive carriers, and 3 explosive cartridges are bound together and put into the PVC plastic pipes. Before each medicine filling, the bottom end part of the PVC plastic pipe is plugged by a cement medicated roll. The middle and rear explosive rolls of the PVC plastic pipe are respectively connected in parallel by 1 section of electric detonators with the same number, and the connecting parts of the detonators and the leads are sealed by insulating tapes.
And (3) sealing the blast hole with water stemming: and sealing the residual blasthole part outside the water stemming by using clay stemming. When the depth of the blast hole exceeds 2.5m, the sealing mud length is not less than 1 m. When the hole depth is more than 5m, the sealing mud length is not less than 1/3 of the hole depth.
The blasting adopts millisecond delay electric detonator, MFd-100 type blasting machine, positive charging, the detonator in the hole adopts parallel connection, the connection mode between blasting cartridges is series connection, and one-time charging is initiated.
The gun hiding time is not less than 30 minutes, and the distance for withdrawing people is not less than 300 m. And after blasting is finished for 30 minutes, the blasting worker firstly patrols the blasting site, and after confirming that no danger exists, the blasting worker disarms and other personnel can enter the working site for operation.
And after the working face of the driving tunnel moves forwards, performing secondary water injection bottom breaking construction on the bottom coal losing area subjected to blasting construction. The purpose is to further inspect and strengthen the blasting pressure relief effect of the bottom coal.
In the stoping process of a stoping working face, the working face is influenced by mutual superposition of stresses such as advanced bearing stress, overburden rock self-weight stress, lateral bearing stress of a peripheral goaf, structural stress, primary pressure of the working face, square working face and periodic pressure, rock burst is extremely easy to occur, and pressure relief of the stoping working face of a coal mine comprises two-way slot advanced loosening blasting pressure relief, two-side covering type drilling pressure relief and roof blasting presplitting pressure relief.
As an embodiment, the pressure relief of the tunneling working surface further comprises reinforcing pressure relief; the reinforcing pressure relief comprises the steps of fault encryption pressure relief, pressure relief before opening a roadway, pressure relief before communicating the roadway and pressure relief in a tunneling disturbance area.
Encrypted pressure relief in fault
There are two situations when the driving face is affected by fault structure: firstly, when heading towards a fault, impact ground pressure is most easily induced when the heading is 20-40 m away from the fault. The fault structure stress influence areas exist at two sides of a fault structure zone, an advance stress influence area is generated in front of a head in the forward advancing process of a tunneling head, and the two stresses are superposed in the range that a working face is 20-40 m close to a fault to enable the pressure of coal rocks in front of the head to be increased rapidly; secondly, hidden faults exist at the periphery of the roadway, the roadway is located in the fault structure stress influence range, the surrounding rock stress is increased, and the possibility of creep type impact exists, so that the encryption pressure relief measures need to be taken in the area influenced by the faults.
When the pressure relief drilling of the construction side part at the head of the tunneling machine is carried out, the condition that the depth of the pressure relief drilling is less than 20m and rocks are seen can be met, and the rock can be seen in three conditions, namely, the rock on the top plate of the coal seam, the rock on the bottom plate of the coal seam and the rock on the fault plane.
The encrypted pressure relief in the fault comprises the following steps: when the depth of the visible rock is less than 20m, drilling a pressure relief borehole at the side part of the roadway; when the included angle between the vertical angle of the pressure relief drilling construction and the inclination angle of the coal seam is more than 21 degrees, the rock on the top plate of the coal seam is found; when the included angle between the vertical angle of the pressure relief drill hole and the inclination angle of the coal seam is less than 0 degree, the rock on the bottom plate of the coal seam is seen; therefore, the included angle between the construction vertical angle of the pressure relief drilling hole and the coal seam is 0-21 degrees.
When the included angle between the pressure relief drilling construction vertical angle and the coal seam dip angle is controlled to be 0-21 degrees and the construction depth is less than 20m, rock is seen, the hidden fault is preliminarily judged to exist in the 20m range of the roadway side part, and when the roadway is positioned on the upper plate of the fault, the roadway is divided into 4 sections according to the rock depth.
In the first section, when the visible rock depth is 0-5 m, construction pressure relief is carried out at an upper angle of 20-40 degrees, if the fault fall is small, a pressure relief drill hole can be constructed according to the angle after passing through another fault disc and being constructed to 20m, the interval of the pressure relief drill hole is encrypted by one time according to the specification, the pressure relief drill hole is required to be encrypted at one side of the fault, and the pressure relief drill hole does not need to be encrypted at the side wall part; if the fault fall is large and rocks still appear within 5m, an inspection hole can be constructed every 10m to determine the fault position and the fall, and pressure relief drill holes can not be constructed between the fault positions and the fall, so that the side wall part is required to be subjected to encryption pressure relief drill holes by the fault.
In the second section, when the visible rock depth is 5-10 m, construction pressure relief is carried out at an upper angle of 10-30 degrees, if the fault fall is small, a pressure relief drill hole can be constructed according to the angle after passing through another fault disc and being constructed to 20m, the side wall part of the fault is required to be provided with an encrypted pressure relief drill hole, and the side wall part is not required to be provided with an encrypted pressure relief drill hole; if the fault fall is large and rock still appears within 10m, the pressure relief drilling holes are required to be encrypted at the two side wall parts.
In the third stage, when the rock depth is 10-15 m, construction pressure relief is carried out at an upper angle of 10-25 degrees, if the fault drop is small and the fault passes through another fault disc and is constructed to 20m, pressure relief drill holes can be constructed according to the angle, and the side wall parts of the faults need to be encrypted and pressure relief drill holes do not need to be encrypted; if the fault fall is large and rock still exists within 15m, the pressure relief drilling holes are required to be encrypted at the two side wall parts.
In the fourth section, when the rock depth is 15-20 m, construction pressure relief is carried out at an upward angle of 5-20 degrees, if the fault layer drop is small and the fault layer passes through another fault disc and is constructed to 20m, pressure relief drill holes can be constructed according to the angle, and the side wall parts of the faults need to be provided with encrypted pressure relief drill holes, and the side wall parts do not need to be encrypted; if the fault fall is large and rock still exists within 20m, the pressure relief drilling holes are required to be encrypted at the two side wall parts.
Pressure relief before opening door of tunnel
When the tunnel is opened, coal bodies on two sides of the tunnel are influenced by tunnel excavation, the height of the tunnel from the coal wall to the inner side is 2.5-3.5 times of that of the low-stress area, the response force of superposition of lateral supporting stress of the tunnel and self-weight stress of an overlying rock stratum to the inner side is gradually increased, the tunnel is opened, and the tunnel is excavated from the low-stress area to the high-stress area, so that impact is easy to occur.
And (3) at the opening position of the roadway, leaving 10m on each of two sides of the central line of the roadway without pressure relief, and before operation, keeping the distance of 1m between 10m and 20m on two sides, wherein the diameter of a drilled hole is 110mm, and the depth of the drilled hole is 20 m.
Release before the tunnel opens the door includes: constructing pressure relief drill holes 10m inwards in the opening of the door in the roadway opening acute angle area; constructing pressure relief drill holes in the inner 8m of the opening door in the obtuse angle area; and constructing pressure relief drill holes in the range of 10m above and below the center line of the side wall part of the opening side of the roadway at the interval of 1m, the diameter of the drill hole of 110mm and the depth of the drill hole of 20 m.
Pressure relief before tunnel penetration
Before the roadway is about to be communicated, the advance supporting stress of the working face is transferred to the coal pillar at the head-on position to the communicating point, the stress of the coal pillar is increased, and the coal pillar is influenced by the tunneling disturbance and is easy to impact and show.
Before the penetration, reinforcing and pressure relief measures are firstly taken for the roadway at the periphery of the pre-penetration point, and the roadway within the range of 20m around the penetration point is drilled for pressure relief, so that the impact caused by the increase of the stress of the roadway at the periphery of the penetration point is prevented; the tunneling head is advanced to release pressure and is penetrated by at least 20m in advance, and the impact from the front of the head to the coal pillar penetrating area is prevented.
The release includes before the tunnel link up:
when two tunnels which are tunneled in opposite directions are through 150m, one of the two tunnels is paused to be tunneled;
when the distance is 50m, the coal dust quantity of two sides of the roadway must be detected once every day by a drilling cutting method during the tunneling; the detection holes are constructed by a frame column hand-held pneumatic drilling machine, 1 detection hole is constructed on each of two sides of the roadway, and the depth of each detection hole is 20 m. The maximum coal dust amount critical value and the drilling dust amount early warning index.
Furthermore, if the pulverized coal amount exceeds the standard or the drill jamming phenomenon occurs, pressure relief must be carried out firstly, detection is carried out again after the construction of pressure relief drilling, if the pulverized coal amount still exceeds the standard, the number of the pressure relief drilling holes must be increased until the pulverized coal amount is normal, and construction can be carried out after the pressure is stable.
Preferably, when the distance from the through point is at least 20m, two pressure relief drill holes are constructed in the center of the head of the working face and are drilled through with the through position, and after the two pressure relief drill holes are drilled through, the pressure relief drill holes in the center of the head of the working face are not constructed. The left and right 45-degree normal construction of the head-on working face leads to pressure relief and drilling, and the hole depth is 15 m. And (5) normally constructing pressure relief drill holes on the two sides according to pressure relief regulations. The pressure display condition of the working surface is observed at any time, when the pressure display is large, all personnel need to withdraw to the position beyond 300m of the working surface immediately, the waiting time exceeds 30 minutes, construction can be carried out after the pressure is stable, and fences and warning marks are arranged at the positions 60m above and below the through point position.
Pressure relief in tunneling disturbance area
When the tunneling roadway is excavated close to the old roadway, the disturbance of the tunneling head-on can affect the peripheral old roadway, the pressure relief time of the old roadway is too long, the stress can be accumulated again, and the peripheral tunneling head-on disturbance can induce the impact of the old roadway. And evaluating the distance between the excavation roadway and the peripheral old roadway and the stress condition of the old roadway, and taking reinforcement pressure relief measures on the roadway in the disturbance area in advance.
The pressure relief drilling parameters are aperture 150mm, depth 20m and interval 4 m; the aperture is 110mm, the depth is 20m, and the distance is 2 m.
In summary, the invention provides a method for preventing and controlling pressure relief of a strong-impact coal seam, which adopts a head-on advanced drilling pressure relief mode, a two-side covering type drilling pressure relief mode and a bottom breaking pressure relief mode when meeting bottom coal explosion on a tunneling working face. The pressure relief drill holes are drilled in the roadway, so that the stress around the roadway is effectively reduced. The stress distribution is moved to the deep part of the coal bed, the stability of the tunneling working face is effectively guaranteed, and the safe tunneling of the roadway is guaranteed.
The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. A strong impact coal seam pressure relief control method is characterized by comprising the steps of pressure relief of a tunneling working face for guaranteeing safe tunneling of a roadway;
the pressure relief of the tunneling working face comprises head-on advanced drilling pressure relief, two-side covering type drilling pressure relief and bottom breaking pressure relief in case of bottom coal explosion;
head-on advance drilling release includes: constructing three pressure relief drill holes at the head of the driving face; the pressure relief drill holes are arranged at the positions which are not less than 0.5m away from the roadway bottom plate;
the diameter of the pressure relief drill hole is 150mm, the depth of the pressure relief drill hole is 15m, and the pressure relief is carried out once every 5m of tunneling, so that a tunneling head-on is kept to be not less than 10m of a pressure relief protective belt;
the two sides cover formula drilling release includes: respectively drilling pressure relief drill holes on two sides of the roadway, wherein the distance between two adjacent holes is not more than 2 m; the diameter of the pressure relief drill hole is 150mm, the hole depth is 20m, and the pressure relief drill hole is arranged at a position which is not less than 0.5m away from the roadway bottom plate; the maximum distance between the pressure relief drill holes of the two sides and the head is not more than 8 m;
the bottom coal explosion breaking bottom pressure relief includes: drilling blast holes on a roadway bottom plate, filling explosives for blasting, and destroying the bottom plate structure, so that pressure relief of drilling surrounding rocks and transfer of a horizontal stress peak value in the bottom plate to the deep part of the bottom plate are promoted, and further, the impact of the bottom plate is eliminated.
2. The method for preventing and treating pressure relief of the high-impact coal seam according to claim 1, wherein the arrangement positions of the pressure relief drill holes for pressure relief of the head-on advanced drill holes are as follows: one is arranged at the center of the head, and two sides are respectively arranged at 45 degrees. The heading is one-shift pressure relief two-shift tunneling every day, so that the heading always keeps advancing to a pressure relief protective belt of not less than 10 m.
3. The method for controlling pressure relief of a high impact coal seam according to claim 2, wherein when the pressure relief drill hole is drilled to a predetermined depth due to a power abnormality, the following steps are performed: and (5) alternately constructing at 0.5-1 m positions on two sides of the pressure relief drill hole, and circularly punching to mutually draw out coal powder until the coal powder is drilled to a preset depth.
4. The method for preventing and treating pressure relief of the high-impact coal seam according to claim 1, wherein the blastholes are arranged at equal intervals downwards along the bottom of the roadway at an angle of 90 degrees, the interval is 0.8m, the explosives are second-stage emulsion explosives, the specification is phi 32mm, × 210mm and 210mm, and each explosive is 0.2 kg.
5. The method for preventing and treating pressure relief of the high-impact coal seam according to claim 4, wherein the coal dust in blast holes is discharged before the explosive is filled; the charging adopts the filling of separated holes; when the hole depth is larger than 1.5m and smaller than 5m, two bundles of 3 blocks are charged; when the hole depth is larger than 5m, three bundles of 3 blocks are filled.
6. The method for controlling pressure relief of a high-impact coal seam according to claim 5, wherein the blastholes are sealed by using water stemming: the remaining blast hole part outside the water stemming is sealed by clay stemming; when the depth of the blast hole exceeds 2.5m, the length of the sealing mud is not less than 1 m; when the hole depth is more than 5m, the sealing mud length is not less than 1/3 of the hole depth.
7. The method for preventing and treating pressure relief of the high-impact coal seam according to claims 1-6, wherein the pressure relief of the driving face further comprises reinforcing pressure relief; the reinforcement pressure relief comprises the steps of fault encryption pressure relief, pressure relief before opening a roadway, pressure relief before communicating the roadway and pressure relief in a tunneling disturbance area.
8. The method for controlling pressure relief of a high impact coal seam according to claim 7, wherein the fault encryption pressure relief comprises: when the depth of the visible rock is less than 20m, drilling a pressure relief borehole at the side part of the roadway; and the included angle between the construction vertical angle of the pressure relief drilling hole and the coal seam is 0-21 degrees.
9. The method for preventing and treating pressure relief of the high-impact coal seam according to claim 7, wherein the pressure relief before the opening of the roadway comprises the following steps: constructing pressure relief drill holes 10m inwards in the opening of the door in the roadway opening acute angle area; constructing pressure relief drill holes in the inner 8m of the opening door in the obtuse angle area; and constructing pressure relief drill holes in the range of 10m above and below the center line of the side wall part of the opening side of the roadway at the interval of 1m, the diameter of the drill hole of 110mm and the depth of the drill hole of 20 m.
10. The method for preventing and treating pressure relief of the high-impact coal seam according to claim 7, wherein the pressure relief before the through-penetration of the roadway comprises: when two tunnels which are tunneled in opposite directions are through 150m, one of the two tunnels is paused to be tunneled;
when the distance is 50m, the coal dust amount detection is carried out on two sides of the roadway once every day by using a drilling cutting method during the tunneling; the inspection holes are constructed by a frame column hand-held pneumatic drilling machine, 1 inspection hole is constructed on each of two sides of the roadway, and the depth of each inspection hole is 20 m.
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