CN112377193B - Deep well small coal pillar gob-side entry retaining method based on top breaking and pressure relief of lower key layer of top plate - Google Patents
Deep well small coal pillar gob-side entry retaining method based on top breaking and pressure relief of lower key layer of top plate Download PDFInfo
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21C—MINING OR QUARRYING
- E21C41/00—Methods of underground or surface mining; Layouts therefor
- E21C41/16—Methods of underground mining; Layouts therefor
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- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/04—Directional drilling
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- E—FIXED CONSTRUCTIONS
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- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D20/00—Setting anchoring-bolts
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21D—SHAFTS; TUNNELS; GALLERIES; LARGE UNDERGROUND CHAMBERS
- E21D21/00—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection
- E21D21/02—Anchoring-bolts for roof, floor in galleries or longwall working, or shaft-lining protection having means for indicating tension
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
- E21F17/103—Dams, e.g. for ventilation
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
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Abstract
The invention provides a deep well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of a lower key layer of a roof, relates to the technical field of coal mining, and improves ventilation and support in deep well gob-side entry retaining. The method comprises the following steps: determining a roof geological condition, determining blasting parameters according to the roof geological condition, numerically simulating the top breaking and pressure relief effects of lower key layers with different thicknesses, and determining top breaking parameters of a roadway; then, constructing and blasting in the test roadway, and arranging a displacement monitoring station, an anchor rod and an anchor cable stress monitoring station on surrounding rock in the roadway; and correcting support parameters, constructing and blasting in the roadway of the gob-side entry retaining, and supporting according to the corrected support parameters. According to the method, blasting is carried out on one side of the coal seam roof, which is deviated from solid coal, and the stress transfer of the key layer is cut off on the lower key layer of the pre-cracked coal seam roof, so that high stress acting on the small coal pillars and the gob-side entry retaining is transferred, the roadway environment is improved, and the maintenance of the roadway is facilitated.
Description
Technical Field
The invention relates to the technical field of coal mining, in particular to a pressure relief and support method for a small coal pillar gob-side entry retaining of a deep well.
Background
Along with the gradual depletion of shallow resources of coal mines, the mining depth of the coal mines is increased year by year, coal seam occurrence conditions are more and more complicated, the problems of rock burst, coal and gas outburst, high-temperature thermal damage and the like seriously threaten the safe production of the mines, and the problem of continuous tension of excavation is increasingly highlighted, particularly for old mines and mines with complicated conditions, the safe and efficient production of the mines is seriously restricted. The existing gob-side entry driving arrangement mode which is commonly adopted at present has the contradiction of tension in excavation continuation and series ventilation of a high gas mine working face; although the problem can be solved by adopting a wide coal pillar roadway protection mode, on one hand, the larger coal loss is caused, and more importantly, high stress concentration is inevitably formed on the deep well coal pillar, so that the disaster accident of rock burst is easily induced.
The gob-side entry retaining is to retain the stoping roadway of the previous section for the next section by adopting a certain technical means, and the technology has the advantages of reducing roadway excavation amount, improving the recovery rate of coal resources, realizing Y-shaped ventilation, reducing the gas accumulation at corners of a working face and the like. However, the existing roadway-side supporting modes (such as a wood crib, a dense pillar, a gangue belt, a concrete block, a paste and the like) without a coal pillar are adopted, and due to the large pressure of a deep mine, the existing supporting modes cannot effectively solve the technical problems of difficult ventilation, natural air leakage, difficult supporting and the like of a deep thick coal seam high-gas mine. In addition, the roof cutting pressure relief automatic roadway-forming coal-pillar-free mining technology is also started to be applied, the roof cutting pressure relief automatic roadway-forming coal-pillar-free mining technology strongly supports a stoping roadway roof through a roof directional presplitting joint, and partial rock mass of the roof is cut down along the presplitting joint under the action of the mine pressure of a roof stratum at the mining area side, so that automatic roadway forming and coal-pillar-free mining are realized. But the roof-cutting self-entry technology needs to perform super-strong support on gob-side entry retaining, the support difficulty is high, the cost is high, and the roadside gangue-blocking system is difficult to block the permeation of harmful gas; in addition, the roof cutting pressure relief self-entry coal pillar-free mining technology is seriously influenced by high ground pressure, so that the roof cutting pressure relief self-entry coal pillar-free mining technology is less applied to deep mine mining.
Therefore, in order to solve the contradiction between gob-side entry retaining excavation continuation and roadway ventilation and roadway support in deep mine exploitation, on one hand, the problem of difficult deep well ventilation needs to be solved, particularly for high gas mines, and on the other hand, the small coal pillars are ensured to play a role in isolating harmful gas, water and gangue in the goaf of the upper working face; on the other hand, the problem of tension in excavation continuation is solved, and the balanced and efficient production of a mine is ensured. The deep well gob-side entry retaining is influenced by the dynamic pressure of two mining operations of the upper working face and the working face due to high ground stress of the deep well gob-side entry retaining, and the small coal pillars and the gob-side entry retaining are influenced by very high supporting pressure and mining action, so that entry retaining under normal mining conditions is very difficult.
Disclosure of Invention
In order to improve ventilation and support conditions in a deep well gob-side entry retaining, ensure the stability of small coal pillars and effectively isolate harmful gas on an upper working face, the invention provides a deep well small coal pillar gob-side entry retaining method based on roof breaking pressure relief of a lower key layer of a roof, and the specific technical scheme is as follows.
A deep well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of a lower key layer of a roof comprises the following steps:
A. determining the geological condition of a coal seam roof;
B. determining blasting top breaking parameters according to geological conditions of a coal seam roof, wherein the blasting top breaking parameters comprise the position and the thickness of a lower key layer top breaking;
C. numerically simulating the relation between the broken top thickness and the deformation of the surrounding rock after breaking the top and relieving pressure and the stress of the surrounding rock of the roadway;
D. determining top breaking parameters of the roadway according to the surrounding rock deformation and the roadway stress distribution;
E. constructing blasting in a test roadway according to the top breaking parameters, and arranging a displacement monitoring station, an anchor rod and an anchor cable stress monitoring station on surrounding rocks in the test roadway;
F. correcting support parameters according to the test roadway surface displacement curve, the anchor rod stress monitoring curve and the anchor cable stress monitoring curve;
G. and constructing a blasting roof in the roadway of the gob-side entry retaining, and supporting the roadway of the gob-side entry retaining according to the corrected supporting parameters.
Preferably, the geological conditions of the roof include roof lithology and roof thickness, and the lower key layer transmits stresses from the overburden.
Preferably, the top-breaking parameters comprise drilling parameters and explosive parameters, wherein the drilling parameters comprise the distance of a drilling hole from a working face, the diameter of the drilling hole, the angle of the drilling hole, the depth of the drilling hole and the distance between the drilling holes, and the explosive parameters comprise the blasting radius, the loading capacity and the sealing length.
Preferably, the distance between the drill hole and the roadway side on one side of the solid coal is more than 200mm in the drilling parameters, and the diameter of the drill hole is 48-50 mm; the dip angle of the drill hole in the thin coal seam is 20 degrees, and the dip angle of the drill hole in the medium-thickness coal seam or the thick coal seam is 10-15 degrees; the drilling depth is greater than the thickness of the lower key layer; the distance between the drill holes in the hard rock is 500mm, and the distance between the drill holes in the soft rock is 1000 mm.
It is also preferable that the blasting parameters of the explosive are such that the radius of the borehole is R around the borehole0The radius of the crushing zone is R1Radius of the rupture zone being R2Radius of vibration region is R3Wherein the radius of the rupture zone is the burst radius; and (4) blasting the traditional Chinese medicine rolls to the position of the lower key layer.
More preferably, the burst radius R2The values of (A) are as follows:
wherein α is the stress wave attenuation coefficient, and α is 2-b; b is the ratio of radial stress to tangential stress, and b is μ/(1- μ), P2Is the peak stress of the shock wave at the uncoupled charge coefficient, an
rbIs the borehole radius, STIs the uniaxial tensile strength of the rock, mu is the Poisson's ratio, ρ0Is the density of the explosive, D is the detonation velocity, rcIs the charge radius; and n is the stress increase multiple and is 8-11.
It is further preferred that the energy-gathering pipe is installed in the blast hole, and the energy-gathering direction is parallel to the direction of the roadway.
Further preferably, in the numerical simulation, specifically, UDEC is used to simulate top breaking and pressure relief of the lower key layer of the top plate in the gob-side entry retaining of the deep well small coal pillar, or FLAC3D is used to simulate top breaking and pressure relief of the lower key layer of the top plate in the gob-side entry retaining of the deep well small coal pillar.
Preferably, a broken top parameter corresponding to the minimum value of the deformation of the surrounding rock and the minimum value of the stress distribution of the roadway is selected.
Further preferably, the support parameters include bolt length, anchor cable length, inter-bolt pitch and inter-anchor cable pitch.
The deep well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of the lower key layer of the roof has the beneficial effects that:
(1) through cutting off the lower key layer of the coal seam roof of the 'transmission rock beam' in advance, the high stress acting on the small coal pillar and the gob-side entry retaining is effectively transferred to a coal rock layer at a farther distance, so that the small coal pillar and the gob-side entry retaining are influenced by lower stress action and mining dynamic pressure, the bearing stability of the small coal pillar is facilitated, and the supporting difficulty of the gob-side entry retaining is greatly reduced.
(2) The stability of the small coal pillar not only can isolate harmful gas in the goaf of the previous working face, but also has the functions of waste rock blocking and water blocking; in addition, the small coal pillars are reserved, so that the problem of continuous tension of excavation in deep mining is solved, the efficient production of a mine can be ensured, the large coal pillars are prevented from being reserved, and the extraction rate is ensured;
(3) selecting proper broken top blasting parameters by using numerical simulation, monitoring the supporting effect in a test roadway, and determining reasonable supporting parameters by analysis to ensure the roadway safety of gob-side entry retaining; in addition, the method also ensures the effect of top breaking and pressure relief of the lower key layer by constructing the top breaking and setting drilling parameters and explosive parameters; avoid stress concentration, control tunnel deflection, guarantee ventilation safety.
Drawings
FIG. 1 is a schematic view of arrangement of gob-side entry retaining of small coal pillars of a deep well;
FIG. 2 is a schematic illustration of gob-side entry retaining after face mining;
FIG. 3 is a side view to the solid coal side;
FIG. 4 is a schematic diagram of the stress distribution before the lower key layer is broken and decompressed;
FIG. 5 is a schematic view of the stress distribution after the lower key layer is broken and decompressed;
FIG. 6 is a schematic diagram of blast zone division;
FIG. 7 is a schematic illustration of in-test roadway monitoring;
FIG. 8 is a graph of the amount of roof subsidence before and after roof breaking and pressure relief;
FIG. 9 is a graph of the approach of the side wall of the solid coal side before and after top-breaking pressure relief;
FIG. 10 is a graph showing the amount of lane wall displacement on the side of the coal pillar before and after the top pressure relief is broken;
FIG. 11 is a graph showing the variation of the working resistance of the anchor rod before and after the top is broken and the pressure is released;
FIG. 12 is a graph of station face distance and roof bolt work resistance.
In the figure: 1-upper key layer, 2-sandstone, 3-lower key layer, 4-immediate roof, 5-face to be mined, 6-gob-side entry retaining, 7-coal face air return lane, 8-coal face, 9-preset drilling, 10-pre-splitting joint cutting, and 11-small coal pillar; 12-monitoring the stress of the anchor rod, and 13-monitoring the stress of the anchor cable.
Detailed Description
With reference to fig. 1 to 12, a specific embodiment of the deep-well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of the roof lower key layer according to the present invention will be described.
Example 1
Because of the difficult problems of difficult ventilation of mining roadways and tense mining continuation of deep-well thick coal seams, particularly high-gas mines, a gob-side entry retaining mining roadway arrangement mode is required, but deep-well gob-side entry retaining is influenced by high ground stress and secondary mining dynamic pressure, small coal pillars need to bear very high supporting pressure and mining pressure, and the small coal pillars are difficult to keep stable. In addition, in the small coal pillar gob-side entry retaining mining process, the parameters of construction top breaking pressure relief and support parameters are difficult to determine, so that the deep well small coal pillar gob-side entry retaining method based on top breaking pressure relief of the lower key layer of the top plate is provided, and the specific steps comprise:
step A, determining the geological condition of a coal seam roof; the geological conditions of the top plate comprise the lithology and the thickness of the top plate, the joint structure, the cementation degree, the structural development (fault, flexure and the like), the stability and the like of the top plate, can be determined according to mine engineering measurement, mine geological exploration data and the like, and can also be actually explored at a working face position.
And B, determining blasting top breaking parameters through theoretical calculation according to geological conditions of the coal seam roof, wherein the blasting top breaking parameters comprise the position and the thickness of the top breaking of a lower key layer, and the lower key layer transmits the stress from the overlying rock stratum.
The burial depth of the coal bed of a general deep mine is more than 600m and is influenced by high ground stress; the lower key layer is a rock layer which is above the immediate roof, is closest to the immediate roof, has larger thickness and hard rock and can transfer the stress of the overlying rock layer; as shown in fig. 1 and 2, the first hard rock layer above the sandstone is the lower key layer, and the upper key layer is above the lower key layer. According to the theory of 'transferring rock beams', the immediate roof cannot transfer stress.
And C, numerically simulating the relation between the broken top thickness and the deformation of the surrounding rock after breaking and pressure relief and the stress of the surrounding rock of the roadway. In the numerical simulation, specifically, UDEC (Universal discrete Element Code, a computational analysis program based on the theory of the discrete unit method) is used for simulating top breaking and pressure relief of a lower key layer of a top plate in a deep well small coal pillar gob-side entry retaining, working face parameters and roadway parameters are determined by combining mining design parameters, the thickness and the position of a broken top are determined, and then software is used for simulating the relation between the thickness of the broken top and the deformation of surrounding rock after top breaking and pressure relief and the stress of the surrounding rock of the roadway; or simulating top breaking and pressure relief of a lower key layer of a top plate in a gob-side entry retaining of a deep well small coal pillar by using an FLAC3D (three-dimensional finite difference program for three-dimensional structural stress characteristic simulation and plastic flow analysis), determining working face parameters and roadway parameters by combining mining design parameters, determining the thickness and position of the top breaking, and simulating the relation between the top breaking thickness and the deformation of the surrounding rock after top breaking and pressure relief and the stress of the surrounding rock of the roadway by using software.
And D, determining the top breaking parameters of the roadway according to the deformation of the surrounding rock and the stress distribution of the roadway. Specifically, selecting a broken top parameter corresponding to the minimum value of the deformation of the surrounding rock and the minimum value of the stress distribution of the roadway.
The parameters of the interruption top of the explosive-free blasting machine comprise drilling parameters and explosive parameters, the drilling parameters comprise the distance (the position of a drill hole) of a drill hole ahead of a working surface, the diameter of the drill hole, the angle of the drill hole, the depth of the drill hole, the distance between the drill holes and the like, and the explosive parameters comprise blasting radius, explosive loading, sealing mode, sealing length and the like.
The distance between a drill hole and a roadway side on one side of the solid coal is more than 200mm in the drilling parameters, and the drill hole for blasting is arranged on a top plate of an air return roadway (gob-side entry retaining) of a first mining working face and is deviated to one side of the solid coal; the diameter of the drilled hole is 48-50 mm; the drill holes are obliquely and upwards arranged on the top plate of the roadway, the inclination angle of the drill holes in the thin coal seam is 20 degrees, and the inclination angle of the drill holes in the medium-thickness coal seam or the thick coal seam is 10-15 degrees; the drilling depth is greater than the thickness of the lower key layer, so that the lower key layer can be cut off after blasting; the distance between the drill holes in the hard rock is 500mm, and the distance between the drill holes in the soft rock is 1000 mm.
In the blasting parameters of the explosive, the radius of a drill hole taking the drill hole as a center is R0The radius of the crushing zone is R1Radius of the cracking zone being R2Radius of vibration region is R3Wherein the radius of the rupture zone is the burst radius; and (4) blasting the traditional Chinese medicine rolls to the position of the lower key layer. Blasting radius R2The values of (A) are as follows:
wherein α is the stress wave attenuation coefficient, and α is 2-b; b is the ratio of radial stress to tangential stress, and b is μ/(1- μ), P2Is the peak stress of the shock wave at the uncoupled charge coefficient, an
rbIs the borehole radius, STIs the uniaxial tensile strength of the rock, mu is the Poisson's ratio, ρ0Is the density of the explosive, D is the detonation velocity, rcIs the charge radius; and n is the stress increase multiple and is 8-11.
In addition, pre-splitting can be realized by presetting drilling holes and performing drilling blasting, and an energy-collecting pipe can be arranged in the blasted drilling holes, wherein the energy-collecting direction is parallel to the trend of a roadway, so that cutting joints can be formed better, and splitting of a lower key layer is realized.
And E, constructing and blasting in the test tunnel according to the top breaking parameters, wherein the test tunnel is a tunnel with the length of about 60m of the coal face of the selected gob-side entry retaining, a displacement monitoring station, an anchor rod and an anchor cable stress monitoring station are arranged on surrounding rocks in the test tunnel, and a tunnel surface displacement curve, an anchor rod stress monitoring curve and an anchor cable stress monitoring curve of the tunnel under the current support are determined through the monitoring stations.
And F, correcting support parameters according to the test roadway surface displacement curve, the anchor rod stress monitoring curve and the anchor cable stress monitoring curve. The support parameters comprise the length of anchor rods, the length of anchor cables, the pitch between the anchor rods and the pitch between the anchor cables, and when the displacement of the surface of the roadway is too large, the support parameters need to be adjusted to strengthen the support; and ensuring that the stress of the anchor rod and the stress of the anchor cable are within the set effective support range.
And G, continuing mining, constructing a blasting roof in the roadway of the gob-side entry retaining, and supporting the roadway of the gob-side entry retaining according to the corrected supporting parameters.
Example 2
On the basis of the embodiment 1, taking a working face of a deep well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of a lower key layer of a roof as an example, the supporting effect of the method is further explained by monitoring conditions.
As shown in fig. 7 to 10, by comparing the roof subsidence, the entity coal side roadway side approach, the roadway side approach and the anchor rod working resistance change before and after top breaking and pressure relief, high stress acting on the small coal pillar and the gob-side entry retaining is effectively transferred to a coal rock layer farther away by cutting off the lower key layer of the coal seam roof of the "transfer rock beam" in advance, so that the small coal pillar and the gob-side entry retaining are influenced by lower stress and mining dynamic pressure, thereby being beneficial to bearing stability of the small coal pillar and greatly reducing the support difficulty of the gob-side entry retaining; in addition, the stability of the small coal pillar not only can isolate harmful gas in the goaf of the previous working face, but also has the functions of waste rock blocking and water blocking; in addition, the small coal pillars are reserved, so that the problem of continuous tension of excavation in deep mining is solved, the efficient production of a mine can be ensured, the large coal pillars are prevented from being reserved, and the extraction rate is ensured; the method can also effectively avoid stress concentration, control the deformation of the roadway and ensure the ventilation safety. After the working face starts to be pushed, the advance supporting pressure and the lateral supporting pressure concentration area are transferred from a basically top-coated unbroken rock stratum (an upper key layer) to the center position of the next working face, and the stress at the position along the gob-side entry retaining position is smaller; the method can effectively transfer the stress concentration area at the gob-side entry retaining position, and the deformation amount of the gob-side entry retaining is small.
It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.
Claims (10)
1. A deep well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of a lower key layer of a roof is characterized by comprising the following steps:
A. determining the geological condition of a coal seam roof;
B. determining blasting top breaking parameters according to geological conditions of a coal seam roof, wherein the blasting top breaking parameters comprise the position and the thickness of a lower key layer top breaking;
C. numerically simulating the relation between the broken top thickness and the deformation of the surrounding rock after breaking the top and relieving pressure and the stress of the surrounding rock of the roadway;
D. determining top breaking parameters of the roadway according to the surrounding rock deformation and the roadway stress distribution;
E. constructing blasting in a test roadway according to the top breaking parameters, and arranging a displacement monitoring station, an anchor rod and an anchor cable stress monitoring station on surrounding rocks in the test roadway;
F. correcting support parameters according to the test roadway surface displacement curve, the anchor rod stress monitoring curve and the anchor cable stress monitoring curve;
G. and constructing a blasting roof in the roadway of the gob-side entry retaining, and supporting the roadway of the gob-side entry retaining according to the corrected supporting parameters.
2. The deep well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of a roof lower key layer according to claim 1, wherein the geological conditions of the roof include roof lithology and roof thickness, and the lower key layer transmits stress from an overlying rock layer.
3. The deep well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of the lower key layer of the roof, according to claim 1, is characterized in that the roof breaking parameters comprise drilling parameters and explosive parameters, wherein the drilling parameters comprise a distance of a drilling advance working face, a drilling diameter, a drilling angle, a drilling depth and a drilling interval, and the explosive parameters comprise a blasting radius, a charging amount and a seal length.
4. The deep-well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of the lower key layer of the roof, according to claim 3, is characterized in that the distance between a drill hole and a side entry wall of solid coal is greater than 200mm in the drilling parameters, and the diameter of the drill hole is 48-50 mm; the inclination angle between the drill hole in the thin coal seam and the vertical direction is 20 degrees, the inclination angle between the drill hole in the medium-thickness coal seam or the thick coal seam and the vertical direction is 10-15 degrees, and the drill hole is deviated to one side of the solid coal; the drilling depth is greater than the thickness of the lower key layer; the distance between the drill holes in the hard rock is 500mm, and the distance between the drill holes in the soft rock is 1000 mm.
5. The deep well small coal pillar gob-side entry retaining method based on top breaking and pressure relief of the top plate lower key layer according to claim 3, wherein in the explosive parameters, the radius of a drill hole with the drill hole as a center is R0The radius of the crushing zone is R1Radius of the cracking zone being R2Radius of vibration region is R3Wherein the radius of the rupture zone is the burst radius; and (4) blasting the traditional Chinese medicine rolls to the position of the lower key layer.
6. The deep-well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of the roof lower key layer as claimed in claim 5, wherein the blasting radius R is2The values of (A) are as follows:
wherein α is the stress wave attenuation coefficient, and α is 2-b; b is the ratio of radial stress to tangential stress, and b is μ/(1- μ), P2Is the peak stress of the shock wave at the uncoupled charge coefficient, an
rbIs the borehole radius, STIs the uniaxial tensile strength of the rock, mu is the Poisson's ratio, ρ0Is the density of the explosive, D is the detonation velocity, rcIs the charge radius; and n is the stress increase multiple and is 8-11.
7. The deep-well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of the lower key layer of the roof as claimed in claim 5, wherein an energy-gathering pipe is installed in a blasting borehole, and the energy-gathering direction is parallel to the direction of the roadway.
8. The deep-well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of the lower key layer of the roof is characterized in that in numerical simulation, UDEC is used for simulating roof breaking and pressure relief of the lower key layer of the roof in the deep-well small coal pillar gob-side entry retaining, or FLAC3D is used for simulating roof breaking and pressure relief of the lower key layer of the roof in the deep-well small coal pillar gob-side entry retaining.
9. The deep-well small coal pillar gob-side entry retaining method based on top breaking and pressure relief of the top plate lower key layer according to claim 1, characterized by selecting top breaking parameters corresponding to a minimum value of deformation of surrounding rocks and a minimum value of stress distribution of a roadway.
10. The deep-well small coal pillar gob-side entry retaining method based on roof breaking and pressure relief of the lower key layer of the roof, according to claim 1, is characterized in that the support parameters comprise anchor rod length, anchor cable length, inter-anchor rod row spacing and inter-anchor cable row spacing.
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| CN114577078A (en) * | 2022-01-26 | 2022-06-03 | 安徽理工大学 | Positive fault blasting method for fully mechanized excavation face through hard rock |
| CN114858019B (en) * | 2022-06-24 | 2023-10-20 | 贵州盘江精煤股份有限公司 | Roof cutting blasting method for transportation lane |
| CN115234287A (en) * | 2022-07-13 | 2022-10-25 | 安徽理工大学 | Energy-gathered blasting pressure-relief permeability-increasing method for top plate of soft coal seam in reverse fault structural area |
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| CN101713290A (en) * | 2009-12-10 | 2010-05-26 | 天地科技股份有限公司 | Method for clearing rock burst of full-mine laneway deep in mine |
| CN101881167A (en) * | 2010-06-04 | 2010-11-10 | 山东华恒矿业有限公司 | Coal face stump mining method |
| CN104763425A (en) * | 2015-02-03 | 2015-07-08 | 杨洪兴 | Pressure relief presplitting blasting gob-side entry retaining pillar-free mining method |
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| CN101713290A (en) * | 2009-12-10 | 2010-05-26 | 天地科技股份有限公司 | Method for clearing rock burst of full-mine laneway deep in mine |
| CN101881167A (en) * | 2010-06-04 | 2010-11-10 | 山东华恒矿业有限公司 | Coal face stump mining method |
| CN104763425A (en) * | 2015-02-03 | 2015-07-08 | 杨洪兴 | Pressure relief presplitting blasting gob-side entry retaining pillar-free mining method |
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