CN113738363B - High-low-level broken roof pressure relief method for continuous multilayer hard roof coal seam - Google Patents
High-low-level broken roof pressure relief method for continuous multilayer hard roof coal seam Download PDFInfo
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- CN113738363B CN113738363B CN202111081987.0A CN202111081987A CN113738363B CN 113738363 B CN113738363 B CN 113738363B CN 202111081987 A CN202111081987 A CN 202111081987A CN 113738363 B CN113738363 B CN 113738363B
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- 239000003245 coal Substances 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 35
- 238000005422 blasting Methods 0.000 claims abstract description 27
- 238000005553 drilling Methods 0.000 claims abstract description 27
- 239000011435 rock Substances 0.000 claims abstract description 26
- 238000010276 construction Methods 0.000 claims abstract description 17
- 230000000694 effects Effects 0.000 claims abstract description 11
- 238000005520 cutting process Methods 0.000 claims abstract description 9
- 238000005065 mining Methods 0.000 claims abstract description 9
- 238000007689 inspection Methods 0.000 claims abstract description 4
- 239000004576 sand Substances 0.000 claims description 18
- 230000015572 biosynthetic process Effects 0.000 claims description 10
- 238000005755 formation reaction Methods 0.000 claims description 10
- 238000005336 cracking Methods 0.000 claims description 4
- 238000004880 explosion Methods 0.000 claims description 3
- 238000005452 bending Methods 0.000 claims description 2
- 239000002817 coal dust Substances 0.000 claims description 2
- 238000005259 measurement Methods 0.000 claims description 2
- 241000237503 Pectinidae Species 0.000 claims 1
- 235000020637 scallop Nutrition 0.000 claims 1
- 230000008901 benefit Effects 0.000 abstract description 3
- 239000010410 layer Substances 0.000 description 46
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Classifications
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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
- E21C41/18—Methods of underground mining; Layouts therefor for brown or hard coal
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- 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
- 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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D1/00—Blasting methods or apparatus, e.g. loading or tamping
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42D—BLASTING
- F42D3/00—Particular applications of blasting techniques
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- Environmental & Geological Engineering (AREA)
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Abstract
The invention belongs to the technical field of coal exploitation, and particularly discloses a high-low broken roof pressure relief method for a continuous multilayer hard roof coal seam, which comprises the steps of calculating a plurality of pre-ground fracturing rock layers with fracturing property by utilizing a key layer theory, and determining broken roof positions; drilling inclination angles and hole depths are designed according to the broken top layer and the construction capability of the drilling machine, and holes are drilled from the return air cis-slot and the transportation cis-slot to the broken top layer respectively; reasonable construction of roof blast holes, ensuring that the advanced working surface of the roof breaking engineering is not less than the mining influence range, and reducing impact threat during construction; the charging and blasting time is reasonably selected, and the same group of sector holes are detonated simultaneously; and carrying out effect inspection on the construction range by a microseismic method or a drilling cuttings method. The invention solves the problem of safe exploitation of rock burst coal beds of key layers of the multilayer hard roof to a certain extent, has certain innovation and popularization and application values, and has remarkable social benefit.
Description
Technical Field
The invention belongs to the technical field of coal exploitation, and particularly relates to a high-low broken roof pressure relief method for a continuous multilayer hard roof coal seam.
Background
In recent years, with the increasing of coal mining depth in China, the problem of impact and mine pressure in many mining areas is more and more serious, and a great part of factors causing the problem are that the goaf roof is too hard and difficult to collapse. If the hard roof can not be subjected to timely pressure relief treatment in the coal mining process, a large-area suspended roof is extremely easy to form, and once the suspended roof is broken, a roadway is damaged instantaneously, so that the safety of a coal mine is seriously threatened.
However, because the hard roof is far away from the coal seam and has large thickness, the treatment difficulty is extremely high, the input cost is high, the currently adopted pressure relief measures such as roof blasting and hydraulic fracturing are adopted, the construction sites are all located in the underground roadway and chamber of the coal mine, only the partial pre-cracking of the low-position roof strata in a small range can be carried out, and for the high-position thick-layer hard roof, the method is difficult to realize the large-range treatment, which is one of the important reasons for causing the frequent occurrence of rock burst accidents.
Therefore, providing a high-low level roof breaking pressure relief method for a continuous multi-layer hard roof coal seam is a technical problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provides a high-low broken roof pressure relief method for a continuous multilayer hard roof coal seam.
The invention provides a high-low level roof breaking pressure relief method for a continuous multilayer hard roof coal seam, which comprises the following steps of:
step 1: calculating a plurality of pre-ground fracturing rock formations with fracturing property by utilizing a key layer theory, and determining the top fracture layer position;
step 2: drilling inclination angles and hole depths are designed according to the broken top layer and the construction capability of the drilling machine, and holes are drilled from the return air cis-slot and the transportation cis-slot to the broken top layer respectively;
step 3: reasonable construction of roof blast holes, ensuring that the advanced working surface of the roof breaking engineering is not less than the mining influence range, and reducing impact threat during construction;
step 4: the charging and blasting time is reasonably selected, and the same group of sector holes are detonated simultaneously;
step 5: and carrying out effect inspection on the construction range by a microseismic method or a drilling cuttings method.
According to a further scheme, residual energy transferred to a working face coal seam by the plurality of pre-ground fracturing rock formations is calculated according to the plurality of pre-ground fracturing rock formations by using a rock formation release energy attenuation characteristic.
Further, in the step 2, the top breaking layer comprises coarse sand layer, medium sand layer, fine sand layer and mud layer, wherein the thickness of the coarse sand layer is 20.08m, the thickness of the medium sand layer is 13.03m, the thickness of the fine sand layer is 10.79m, and the thickness of the mud layer is 1.25m.
Further, the inclination angle of the fine sand layer is 40 degrees, the inclination angle of the medium sand layer is 50 degrees, and the inclination angle of the coarse sand layer is 60 degrees.
Further, the drill holes respectively penetrate through the broken top layer positions.
According to the further scheme, the return air cis-slot and the transportation cis-slot are drilled according to the inclination angles respectively, the number of the drilled holes is 6, and fan-shaped holes are formed.
Further, the blasting depth is determined according to the principle of deep stress concentration areas, and the blasting range is in the stress concentration areas: determining hole distances according to the widths of the crushing area and the cracking area to enable the crushing areas of two adjacent explosion holes to be communicated; the charge length of each borehole is 1/3-1/2 of the borehole depth.
The further scheme is that the blasting mode adopts millisecond detonator grouping blasting.
The further scheme is that the same group of sector holes detonate simultaneously during blasting.
According to the further scheme, the microseismic method is used for accurately calculating the position and energy of a seismic source, and the drilling cuttings method is used for determining the stress state of surrounding rocks of a roadway through measurement of coal dust quantity.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention solves the problem of safe exploitation of rock burst coal beds of key layers of the multilayer hard roof to a certain extent, has certain innovation and popularization and application values, and has remarkable social benefit.
(2) The hard top plate is treated by adopting a high-low top plate presplitting blasting hole mode, so that the roof breaking effect can be effectively enhanced, the periodical step-pressing distance during the pushing and picking period of the working face is controlled, and the safety production is realized.
Drawings
The following drawings are illustrative of the invention and are not intended to limit the scope of the invention, in which:
fig. 1: the invention relates to a flow chart of a high-low position broken roof pressure relief method;
fig. 2: schematic diagram of high-low position broken roof pre-splitting blasting drilling arrangement.
Detailed Description
The present invention will be further described in detail with reference to the following specific examples, which are given by way of illustration, in order to make the objects, technical solutions, design methods and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
As shown in fig. 1, the invention provides a high-low broken roof pressure relief method for a continuous multi-layer hard roof coal seam, which comprises the following steps:
step 1: calculating a plurality of pre-ground fracturing rock formations with fracturing property by utilizing a key layer theory, and determining the top fracture layer position;
step 2: drilling inclination angles and hole depths are designed according to the broken top layer and the construction capability of the drilling machine, and holes are drilled from the return air cis-slot and the transportation cis-slot to the broken top layer respectively;
step 3: reasonable construction of roof blast holes, ensuring that the advanced working surface of the roof breaking engineering is not less than the mining influence range, and reducing impact threat during construction;
step 4: the charging and blasting time is reasonably selected, and the same group of sector holes are detonated simultaneously;
step 5: and carrying out effect inspection on the construction range by a microseismic method or a drilling cuttings method.
Specifically, the heights of a caving zone, a fracture zone and a bending subsidence zone of coal seam exploitation are calculated according to mine geological data, target rock formations needing to be subjected to modified pressure relief are determined in the fracture zone height range according to typical drilling histograms, and then residual energy transferred to a working surface coal seam by the multiple pre-ground fracturing rock formations is calculated according to the multiple pre-ground fracturing rock formations by means of rock formation release energy attenuation characteristics.
In the embodiment, the coal seam adopted by the coal mine is No. 4 coal, and the 4 coal seam is judged to belong to class III and is a coal seam with strong impact tendency according to the national standard GB/T25217.2-2010 method for classifying impact tendency of coal and measuring index by the rock mechanics laboratory of Beijing coal department according to the data measured by the coal sample; the rock layers of the top and the bottom are of class II and are weak impact-prone. At present, mines are developed to three zones, geological conditions of the three zones are greatly changed compared with those of the two zones, the key layers of continuous 3 layers of hard sandstone with the single-layer thickness of more than 10m are mainly formed above a coal seam, and the stress concentration degree of a stope face and two cis-slots can be effectively weakened by the broken roof treatment of the key layers, so that the impact risk is reduced.
As shown in fig. 2, in step 2, the broken top layer includes coarse-grained sandstone layer, medium-grained sandstone layer, fine-grained sandstone layer and mudstone layer, the thickness of the coarse-grained sandstone layer is 20.08m, the thickness of the medium-grained sandstone layer is 13.03m, the thickness of the fine-grained sandstone layer is 10.79m, the thickness of the mudstone layer is 1.25m, the inclination angle of the fine-grained sandstone layer is 40 °, the inclination angle of the medium-grained sandstone layer is 50 °, the inclination angle of the coarse-grained sandstone layer is 60 °, and the drill holes respectively penetrate the broken top layer. As can be seen from FIG. 2, the drill length of the fine sand layer is 10.79/Sin40 degrees, about 16.78m, the drill length of the medium sand layer is 13.3/Sin50 degrees, about 17.36m, and the drill length of the coarse sand layer is 20.08/Sin60 degrees, about 23.18m. The blasting long drilling holes are used for cutting off the propagation paths of the high-position advanced supporting pressure of the top plate, and the blasting short drilling holes are used for cutting off the propagation paths of the low-position advanced supporting pressure of the top plate, so that the main body roadway near the mining area is free from the influence of the exploitation dynamic pressure, the stress environment of surrounding rock of the roadway is improved, and the deformation of the roadway is weakened.
Optionally, the return air cis-slot and the transportation cis-slot are drilled according to the inclination angles respectively, the number of the drilled holes is 6, and fan-shaped holes are formed, so that the blasting effect is enhanced.
Optionally, the determination of the blasting depth should be in accordance with the principle of deep into the stress concentration area, and the blasting range should be in the stress concentration area: determining hole distances according to the widths of the crushing area and the cracking area to enable the crushing areas of two adjacent explosion holes to be communicated; the charge length of each borehole is 1/3-1/2 of the borehole depth. The loading capacity is a key parameter related to the blasting pressure relief effect, and unreasonable loading capacity cannot achieve the pressure relief effect, but can damage a roadway and even induce rock burst, so that reasonable loading capacity is very important. The layer water injection is to inject water to the coal body at high pressure so as to change the physical properties of the coal body and generate cracks around the coal rock body, thereby achieving the purposes of reducing the compressive strength of the coal body and destroying the original structure to release accumulated energy and reduce the stress, and the unidirectional compressive strength of the stratum rock stratum of the coal system is reduced along with the increase of the water content.
Optionally, the blasting mode adopts millisecond detonators for grouping blasting, and the same group of sector holes are detonated simultaneously during blasting, so that blasting effect is ensured.
In the embodiment, the microseismic method can monitor the mine earthquake caused by the mining activity of the whole mine area in a real-time, long-distance and large-range manner, and can accurately calculate the position and energy of the earthquake focus.
The drilling cutting method is also called as a pulverized coal drilling method, and is a method for identifying impact danger according to the discharged pulverized coal quantity, the change rule and related dynamic effects by drilling holes with small diameters (41-50 mm) in a coal bed.
The foregoing description of embodiments of the invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the technical improvements in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.
Claims (6)
1. The high-low broken roof pressure relief method for the continuous multilayer hard roof coal seam is characterized by comprising the following steps of:
step 1: calculating a plurality of pre-ground fracturing rock formations with fracturing property by utilizing a key layer theory, and determining the top fracture layer position;
step 2: drilling inclination angles and hole depths are designed according to the broken top layer and the construction capability of the drilling machine, and holes are drilled from the return air cis-slot and the transportation cis-slot to the broken top layer respectively;
step 3: reasonable construction of roof blast holes ensures that the advanced working face of the roof breaking engineering is not less than the mining influence range, reduces impact threat during construction, ensures that the determination of the blasting depth accords with the principle of deep stress concentration areas, and ensures that the blasting range is in the stress concentration areas: determining hole distances according to the widths of the crushing area and the cracking area to enable the crushing areas of two adjacent explosion holes to be communicated; the charge length of each drilling hole is 1/3-1/2 of the drilling depth;
step 4: the charging and blasting time is reasonably selected, and the same group of sector holes are detonated simultaneously;
step 5: performing effect inspection on the construction range by a microseismic method or a drilling cuttings method;
calculating the heights of a caving zone, a fracture zone and a bending subsidence zone of coal seam exploitation according to mine geological data, determining a target rock stratum needing to be subjected to modified pressure relief in a fracture zone height range according to a typical drilling histogram, and calculating the residual energy transferred to a working surface coal seam by the multiple pre-ground fracturing rock strata according to the multiple pre-ground fracturing rock strata by using a rock stratum release energy attenuation characteristic;
in the step 2, the top breaking layer comprises a coarse-grain sandstone layer, a medium-grain sandstone layer, a fine-grain sandstone layer and a mudstone layer, wherein the thickness of the coarse-grain sandstone layer is 20.08m, the thickness of the medium-grain sandstone layer is 13.03m, the thickness of the fine-grain sandstone layer is 10.79m, and the thickness of the mudstone layer is 1.25m;
the inclination angle of the fine sand layer is 40 degrees, the inclination angle of the middle sand layer is 50 degrees, and the inclination angle of the coarse sand layer is 60 degrees;
the drilling length of the fine sand layer is 10.79/Sin40 degrees, the drilling length of the medium sand layer is 13.3/Sin50 degrees, and the drilling length of the coarse sand layer is 20.08/Sin60 degrees.
2. The method of claim 1, wherein the holes are drilled through the roof fracture zones respectively.
3. The method for high-low level roof breaking and pressure relief of continuous multi-layer hard roof coal seams according to claim 2, wherein the return air cis-slot and the transportation cis-slot are drilled according to the inclination angles respectively, and the number of the drilled holes is 6, so that sector holes are formed.
4. A high and low level roof breaking pressure relief method for a continuous multi-layer hard roof coal seam according to claim 3, wherein the blasting mode adopts millisecond detonator grouping blasting.
5. The method for high and low level roof breaking and pressure relief of a continuous multi-layer hard roof coal seam of claim 4, wherein the same set of scallops are detonated simultaneously during blasting.
6. The high-low level roof breaking pressure relief method for the continuous multilayer hard roof coal seam according to claim 5, wherein the microseismic method is used for accurately calculating the position and energy of a seismic source, and the drilling cutting method is used for determining the stress state of surrounding rocks of a roadway through measurement of the amount of coal dust.
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| CN202111081987.0A CN113738363B (en) | 2021-09-15 | 2021-09-15 | High-low-level broken roof pressure relief method for continuous multilayer hard roof coal seam |
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| CN202111081987.0A CN113738363B (en) | 2021-09-15 | 2021-09-15 | High-low-level broken roof pressure relief method for continuous multilayer hard roof coal seam |
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| CN114542066B (en) * | 2022-01-16 | 2023-02-03 | 中南大学 | Advanced pre-splitting method for coal seam roof |
| CN114542067B (en) * | 2022-01-16 | 2023-02-03 | 中南大学 | Safe mining method for coal seam overlying hard rock stratum |
| CN117948143B (en) * | 2024-03-26 | 2024-05-31 | 煤炭科学技术研究院有限公司 | Roof fracturing method for coal mine working face in initial mining stage |
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| CN104453899A (en) * | 2014-11-06 | 2015-03-25 | 大同煤矿集团有限责任公司 | Safety recovery method of island working surface under complicated condition |
| CN112012742A (en) * | 2020-10-26 | 2020-12-01 | 杨文连 | Method for preventing and controlling rock burst of large-section hole-cutting and downward-digging coal seam of coal mine in steep dip |
| CN112814679A (en) * | 2021-01-07 | 2021-05-18 | 淮南矿业(集团)有限责任公司 | Pre-splitting blasting method for layered inclined fully-mechanized direct-covered hard roof of slowly-inclined thick coal seam |
| CN113027510A (en) * | 2021-03-26 | 2021-06-25 | 安徽理工大学 | Method for extracting pressure-relief gas by blasting permeability-increasing directional long drill hole of thick and hard roof rock layer |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104453899A (en) * | 2014-11-06 | 2015-03-25 | 大同煤矿集团有限责任公司 | Safety recovery method of island working surface under complicated condition |
| CN112012742A (en) * | 2020-10-26 | 2020-12-01 | 杨文连 | Method for preventing and controlling rock burst of large-section hole-cutting and downward-digging coal seam of coal mine in steep dip |
| CN112814679A (en) * | 2021-01-07 | 2021-05-18 | 淮南矿业(集团)有限责任公司 | Pre-splitting blasting method for layered inclined fully-mechanized direct-covered hard roof of slowly-inclined thick coal seam |
| CN113027510A (en) * | 2021-03-26 | 2021-06-25 | 安徽理工大学 | Method for extracting pressure-relief gas by blasting permeability-increasing directional long drill hole of thick and hard roof rock layer |
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