CN114472462B - Underground-aboveground linkage coal gangue disposal system and disposal method - Google Patents
Underground-aboveground linkage coal gangue disposal system and disposal method Download PDFInfo
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- CN114472462B CN114472462B CN202111640225.XA CN202111640225A CN114472462B CN 114472462 B CN114472462 B CN 114472462B CN 202111640225 A CN202111640225 A CN 202111640225A CN 114472462 B CN114472462 B CN 114472462B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09B—DISPOSAL OF SOLID WASTE
- B09B5/00—Operations not covered by a single other subclass or by a single other group in this subclass
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F15/00—Methods or devices for placing filling-up materials in underground workings
- E21F15/005—Methods or devices for placing filling-up materials in underground workings characterised by the kind or composition of the backfilling material
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/91—Use of waste materials as fillers for mortars or concrete
Abstract
The invention provides an underground-aboveground linkage coal gangue disposal system and a disposal method, which comprise an aboveground active coal gangue slurry preparation unit and an underground coal gangue disposal material preparation unit, wherein the aboveground active coal gangue slurry preparation unit is communicated with the underground coal gangue disposal material preparation unit, the aboveground active coal gangue slurry preparation unit is used for transporting prepared active coal gangue slurry to the underground coal gangue disposal material preparation unit, and the underground coal gangue disposal material preparation unit is used for preparing underground coal gangue disposal materials and filling and disposing longwall goafs and/or separation layer spaces. The invention can simultaneously dispose the coal gangue which is being produced from the coal gangue hill and the underground, and realizes the disposal of the gangue without lifting the well and the gangue on the surface.
Description
Technical Field
The invention belongs to the field of coal gangue solid waste disposal and resource utilization, and relates to a downhole-uphole linkage coal gangue disposal system and a disposal method.
Background
The coal gangue is rock with dry basis ash content more than 50% generated in the processes of coal mine well construction, development and excavation, coal mining and coal washing, and the discharge amount accounts for 10% -20% of the coal yield. The coal gangue solid waste occupies a large amount of land resources, causes serious environmental damage, causes pollution to the atmosphere, water sources, soil and the like in different degrees, and can cause geological disasters such as hillock landslide, collapse, debris flow and the like. The 'underground filling of coal gangue and ground backfilling' are new directions for promoting the reduction of the coal gangue and the development of green mining industry, but how to achieve 'zero emission' of the coal gangue is a great problem to be solved urgently.
The existing coal gangue underground disposal technology comprises the following steps: directly throwing waste rock filling, water sand filling and cemented filling. The direct waste rock throwing filling method has potential safety hazard and coal resource waste problems and is forbidden to use; the disposal quantity of easy-to-collapse hole-blocking gangue in water sand filling is limited, and the gangue leachate enters an underground water environment to cause underground water pollution; the cementation filling method is characterized in that materials such as coal gangue, sand, broken stone, coal ash, loess, cement and the like are mixed to form cementation materials for filling underground spaces such as a goaf, a waste roadway, a separation layer and the like, the formed filling slurry contains a large amount of additional materials, the disposal amount of the coal gangue in unit filling amount is limited, the problems of capacity increase, labor hour increase, cost increase and the like exist, in the face of large-scale disposal of the coal gangue and limited underground spaces, the coal gangue cannot be disposed along with mining, the coal gangue after capacity increase cannot be disposed completely, namely, the coal gangue cannot be used up along with mining, and the coal gangue underground filling and ground backfilling cannot be realized at the same time. The coal gangue has activity, and the application of the coal gangue geopolymer prepared from the coal gangue as a filling cementing material in underground disposal of the coal gangue is not available, and the reason is as follows: 1) The coal gangue geopolymer gelling property needs to be excited, the excitation process is complex, and more factors need to be controlled; 2) The underground space of a mine is limited, and the coal gangue crushing and excitation difficulty is high.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a system and a method for disposing underground-aboveground linkage coal gangue.
In order to solve the technical problems, the invention adopts the following technical scheme:
the underground-aboveground linkage coal gangue disposal system comprises an aboveground active coal gangue slurry preparation unit and an underground coal gangue disposal material preparation unit, and is characterized in that the aboveground active coal gangue slurry preparation unit is communicated with the underground coal gangue disposal material preparation unit, the aboveground active coal gangue slurry preparation unit is used for transporting prepared active coal gangue slurry to the underground coal gangue disposal material preparation unit, and the underground coal gangue disposal material preparation unit is used for preparing underground coal gangue disposal materials and filling and disposing long-wall goafs and/or separation layer spaces;
the aboveground active coal gangue slurry preparation unit comprises aboveground crushing equipment, calcining equipment, particle grinding equipment, aboveground pulping equipment and a conveying pipeline which are connected; the aboveground crushing equipment is used for crushing ground coal gangue to obtain coal gangue fine materials; the calcining equipment is used for calcining the coal gangue fine materials and conveying the calcined coal gangue fine materials to the particle grinding equipment; the particle grinding equipment is used for decarbonizing and activating to form activated coal gangue powder, and the aboveground pulping equipment is used for mixing the activated coal gangue powder with water to obtain activated coal gangue slurry; the conveying pipeline is used for conveying the active coal gangue slurry to a preparation unit of underground coal gangue disposal materials in a well;
the underground coal gangue underground disposal material preparation unit comprises an underground coal gangue continuous conveying device, coal gangue underground sorting equipment, underground crushing equipment, underground pulping equipment and a cementing material preparation station which are connected;
the underground coal gangue continuous conveying device is used for conveying coal gangue generated on an underground coal mining working face to the underground coal gangue sorting equipment for sorting; the underground crushing equipment is used for crushing the coal gangue which is sorted by the underground sorting equipment and is used as solid waste to obtain coal gangue aggregate; the cementing material preparation station is communicated with the conveying pipeline through a conveying pipeline in an underground roadway; the cementing material preparation station is used for mixing water glass and an alkaline excitation material, cooling the mixture to prepare an excitation solution, and then mixing the active coal gangue slurry conveyed by the conveying pipeline in the underground roadway with the excitation solution to form a coal gangue-based geopolymer cementing material; the underground pulping equipment is used for mixing the coal gangue-based geopolymer cementing material and the coal gangue aggregate to prepare a coal gangue underground disposal material.
The coal gangue underground treatment material filling system comprises an underground drill site and an equipment room, wherein the underground drill site and the equipment room are connected with the underground pulping equipment through a slurry conveying pipeline, and the coal gangue underground treatment material is filled into a longwall goaf and/or a separation space;
the particle grinding equipment is a ball mill; the underground crushing equipment is internally provided with a crushing system, a screening system and a coarse material reworking system.
The invention discloses an underground disposal method of all coal gangue, which adopts an underground-aboveground linkage coal gangue disposal system to carry out underground disposal of all coal gangue and comprises the following steps:
determining the coal gangue disposal amount of the longwall goaf according to the total void fracture space amount of the longwall goaf, selecting a grouting hole of the longwall goaf, and filling the coal gangue underground disposal material into the longwall goaf through the grouting hole of the longwall goaf according to the coal gangue disposal amount of the longwall goaf;
and/or selecting a grouting layer position of a separation space, determining the coal gangue disposal amount of the separation space according to the maximum limit injection-production ratio of the separation space, and sequentially filling the coal gangue disposal materials into the grouting layer position of the separation space according to the coal gangue disposal amount of the separation space according to a grouting sequence;
and the filling speed of filling the coal gangue underground disposal material is greater than or equal to the coal gangue generation speed.
Further, the total amount of the void fracture space of the longwall gob is determined by the following formula:
V＝λ×2L×l t ×h m
wherein V is the total amount of the space of the gap and the crack of the longwall goaf, and the unit is m 3 (ii) a L is the limit collapse distance, and the unit is m; h is m The unit is m for the mining height of the coal bed; l t Advancing length for coal mining in units of m; lambda is a time factor, and 0.95 is taken when the coal is just mined; within 1 year of exploitation, taking 0.9-0.4; mining for 1 to 3 years, and taking 0.4 to 0.3; mining for more than 3 years, and taking 0.3-0.25;
the limit collapse distance L is determined by the following formula:
L＝3×min{L t ,L s ,L y }
wherein L is t The limit span is formed under the action of bending moment when the old top beam is broken, and the unit is m; l is s The limit span is formed under the action of shear stress when the old top beam is broken, and the unit is m; l is y Is the actual monitored cycle step size in m.
Furthermore, the limit span L formed under the action of bending moment when the old top beam is broken t Calculated by the following formula:
limit span L formed under the action of shear stress when the old top beam is broken s Calculated by the following formula:
wherein σ t Is the basic roof rock tensile strength in kPa; sigma s Is the basic roof rock shear strength in kPa; h is the base top thickness in m; q is the load uniformly distributed on the top of the basic roof, and the unit is kPa;
the substantially top uniform load q is calculated by:
wherein, γ i Is the weight of each stratum at the top of the base layer and has the unit of N/m 3 ；h i Is the thickness of each layer of rock formation substantially on top, in m;
is the average weight of the basic top overburden rock layer and has the unit of N/m 3 ；h c Is the thickness of the basic roof overburden, and the unit is m; the value range of i is a positive integer from 1 to n.
Further, the grouting holes of the selected longwall goaf comprise directional construction grouting holes with the goaf, which is formed in the longwall mining process and is 1-2 m away from the end of the isolation coal pillar, as a target point;
the coal gangue disposal amount of the longwall goaf comprises the coal gangue disposal amount of the longwall goaf determined according to the coal gangue proportion of the filled coal gangue underground disposal material and the total amount of the void fracture space of the longwall goaf.
Further, the selection of the grouting horizon of the separation space comprises the following steps:
step 1, judging the rock stratum rigidity according to a drilling histogram, preliminarily judging a strong bearing rock stratum, and determining a plurality of key layers in the rock stratum;
step 2, calculating the breaking distance of each key layer in the plurality of key layers;
step 3, selecting a position, as a grouting position, of which the final hole position is located above the comprehensive height top boundary of the water flowing fractured zone and is more than 20m, and the breaking distance of the key layer corresponds to a position with a mining limit width larger than the width of a grouting filling working face from the plurality of key layers;
if the selected grouting layer position is one, grouting in the grouting layer position; and if the selected grouting positions are multiple, sequentially grouting the multiple grouting positions according to the sequence of the breaking distance value of each key layer from small to large.
Further, the breaking distance L of the key layer x Calculated from the following formula:
wherein: h is x The thickness of the key layer of the x layer is m; sigma tx The tensile strength of the key layer of the x layer is expressed in kPa; q. q of x The unit of the load borne by the key layer of the x layer is kPa; the value range of x is a positive integer from 1 to n;
the limit mining width corresponding to the breaking distance of the key layer is calculated by the following formula:
wherein s is the ultimate mining width corresponding to the breaking distance of the key layer and is in the unit of m; l is x The breaking distance of the key layer is m; h is the distance between the key layer and the mining coal bed and the unit is m; and delta is the fracture angle of the overlying strata of the coal bed and has the unit of.
Further, the maximum limit injection-production ratio of the separation space is calculated by the following formula:
in the formula: alpha is the maximum limit injection-production ratio of the separation space; s is the limit mining width corresponding to the breaking distance of the key layer, and the unit is m; h z The distance between the grouting filling section and the coal seam is m; h is m The unit is m for the mining height of the coal bed; phi is the full mining angle, and the unit is DEG; h c The height of the caving zone is m; k' p The coefficient of the residual crushing expansion of the goaf is 1.03-1.05; xi is the limiting coefficient of the grouting filling system, filling and mining matching and the like, and the value range is 0.6-0.8.
Furthermore, activated coal gangue powder rich in silicon-aluminum minerals in the coal gangue underground disposal material and the coal gangue aggregate are mixed according to the mass ratio of 1 (1-4);
the coal gangue based geopolymer cementing material comprises the following components in percentage by mass: 200-300 parts of activated coal gangue powder rich in silicon-aluminum minerals, 20-40 parts of water glass, 5-10 parts of alkali excitation materials and 120-900 parts of water;
the activated coal gangue powder rich in the silicon-aluminum mineral is prepared by crushing coal gangue through crushing equipment to ensure that the particle size of the coal gangue is less than 5mm, and adding Na into coal gangue particles with the particle size of less than 5mm 2 CO 3 After the powder is stirred, the mixture is calcined for 0.5 to 4 hours at the high temperature of between 500 and 850 ℃ for decarburization activation, and then ball milling is carried out by a ball mill to obtain the product with the average grain diameter of less than 40 mu m and the specific surface area of between 3500 and 5000cm 2 The activated coal gangue powder per gram, wherein the activated coal gangue powder with the grain diameter of less than 10 mu m accounts for 30-50 percent;
the Na is 2 CO 3 The mixing amount of the powder is 3 per mill of the mass of coal gangue particles smaller than 5 mm;
the modulus of the water glass is 1.0-1.3;
the alkali excitation material comprises one or more of sodium hydroxide, potassium hydroxide or quicklime;
the coal gangue aggregate is coal gangue with the maximum grain diameter of 5-20 mm after the coal gangue is crushed.
Compared with the prior art, the invention has the following technical effects:
the method (1) can simultaneously treat the coal gangue mountain on the ground and the coal gangue being extracted underground, thereby realizing the treatment of the gangue on the ground without lifting the well; (2) The self-activity of the coal gangue is effectively excited by the self-characteristics of the coal gangue to prepare the cementing material, the in-situ crushed coal gangue aggregate can be wrapped and cured to form aggregate slurry, so that underground water pollution caused by infiltration of pollutants due to the fact that the coal gangue is in a high ground stress environment for a long time can be prevented, the coal gangue can be substituted for the doping of cement to promote the maximum disposal of the coal gangue, and the cementing material has a huge popularization and application prospect; (3) The coal gangue underground disposal material is filled into the goaf, so that the broken rock mass in the goaf can be solidified, a top plate is supported, and the problem that the ecological environment is damaged due to surface subsidence caused by overlying strata settlement of the goaf is solved; (4) Filling coal gangue underground disposal materials into the separation space can prevent the main key layer from being broken and can also prevent the ecological environment problem caused by surface subsidence.
Drawings
FIG. 1 is a schematic flow diagram of a downhole-uphole linkage coal gangue disposal system according to the present invention;
FIG. 2 is a schematic view of a downhole-uphole linkage coal gangue disposal system and disposal according to the present invention;
FIG. 3 is a schematic diagram illustrating a separation space disposal in a downhole-uphole linkage coal gangue disposal according to the present invention;
FIG. 4 is a schematic view of disposing a goaf in the underground-aboveground linkage coal gangue disposal of the present invention;
FIG. 5 is a schematic view of a grouting pipe for underground disposal materials with preset coal gangue in a goaf according to the present invention;
the reference numbers are as follows:
1. a coal gangue dump; 2. an uphole crushing device; 3. a calcination apparatus; 4. a particulate grinding device; 5. aboveground pulping equipment; 6. A directional hole; 7. a delivery conduit; 8. conveying pipelines in the underground tunnel; 9. a coal gangue continuous conveying device under the well; 10. coal gangue sorting equipment; 11. a downhole crushing device; 12. a downhole pulping device; 13. a cementitious material preparation station; 14. a slurry delivery pipe; 15. grouting pipes; 16. a gob; 17. isolating the coal pillar; 18. a roadway; 19. underground drill sites and equipment houses; 20. A ground surface; 21. a subterranean formation; 22. a coal seam floor; 23. a top soil layer; 24. a primary key layer; 25. a weak rock stratum; 26. a second sub-key layer; 27 sub-critical layer one; 28, a coal seam roof; 29. a separation space; 1-1, presetting a grouting pipe; 1-2, automatic control valve.
The present invention will be explained in further detail with reference to examples.
Detailed Description
The following embodiments are given as examples of the present invention, and it should be noted that the present invention is not limited to the following embodiments, and all equivalent changes based on the technical solutions of the present invention are included in the protection scope of the present invention.
When grouting is performed in the longwall goaf or the separation space, the two are sequentially grouted. Generally, when a working face is injected along with mining, the goaf is filled firstly, because the goaf is formed firstly, when the working face is pushed to a nearly-intermediate position, a separation space appears, the separation space is filled, and then after the separation space is filled, the goaf can be injected at a pushing mining ending section of the working face. And grouting can be performed to the corresponding crack space through directional drilling according to the operation near the working surface at the time of the crack space.
The following is an explanation of technical terms related to the present invention:
the injection-production ratio is the percentage of the volume of the compacted ash filled in the overlying rock to the volume of the produced rock.
A delamination space refers to the space between layers that results from unsynchronized subsidence between different strata of the roof.
The grouting holes of the longwall goaf are directional construction grouting holes taking the goaf at the position 1-2 m away from the end part of the isolation coal pillar during longwall mining as a target point; after mining, the middle part of the goaf is compacted, the closer to the isolation coal pillar, the larger the injectable space of the goaf, so that the goaf in the goaf formed by longwall mining, which is 1-2 m away from the end of the isolation coal pillar, is taken as a target point directional construction grouting hole, and the grouting position is determined by selecting the grouting hole. The "end portions" refer to both ends of the horizontal plane, and as shown in fig. 4, the distance from the grouting pipe 15 located at the left end of the isolation pillar 17 to the gob 16 is 1 to 2m.
The relevant parameters in the scheme are explained as follows:
example 1
According to the technical scheme, with reference to fig. 1, the embodiment provides a downhole-uphole linkage coal gangue disposal system, which includes an uphole active coal gangue slurry preparation unit and a downhole coal gangue underground disposal material preparation unit, wherein the uphole active coal gangue slurry preparation unit is communicated with the downhole coal gangue underground disposal material preparation unit, the uphole active coal gangue slurry preparation unit is used for transporting the prepared active coal gangue slurry to the downhole coal gangue underground disposal material preparation unit, and the downhole coal gangue underground disposal material preparation unit is used for preparing a coal gangue underground disposal material and filling and disposing a longwall goaf and/or a separation space;
the aboveground active coal gangue slurry preparation unit comprises an aboveground crushing device 2, a calcining device 3, a particle grinding device 4, an aboveground pulping device 5 and a conveying pipeline 7 which are connected; the aboveground crushing equipment 2 is used for crushing ground coal gangue to obtain coal gangue fine materials; the calcining equipment 3 is used for calcining the coal gangue fine materials and then conveying the calcined coal gangue fine materials to the particle grinding equipment 4; the particle grinding equipment 4 carries out decarburization and activation to form activated coal gangue powder, and the aboveground pulping equipment 5 is used for mixing the activated coal gangue powder with water to obtain activated coal gangue slurry; the conveying pipeline 7 is used for conveying the active coal gangue slurry to a preparation unit of underground coal gangue disposal materials;
specifically, the conveying mode among the aboveground crushing equipment 2, the calcining equipment 3, the particle grinding equipment 4 and the aboveground pulping equipment 5 is a continuous conveying mode, the continuous conveying mode comprises a belt conveying mode and the like, and the whole process is closed, so that dust pollution is prevented;
the method comprises the following steps: conveying the coal gangue collected from a ground 20 coal gangue dump 1 to an aboveground crushing device 2 for crushing in a continuous conveying mode, crushing the coal gangue until the particle size is less than 5mm, and adding Na into the coal gangue particles with the particle size less than 5mm 2 CO 3 After the powder is uniformly stirred, the crushed coal gangue fine materials are conveyed to a calcining device 3 in a continuous conveying mode to be calcined and conveyed to a particle grinding device 4, decarburization and activation are carried out to form activated coal gangue powder, the activated coal gangue powder is conveyed to an aboveground pulping device 5 to be uniformly mixed with water to prepare activated coal gangue slurry, drilling is carried out from the ground to the underground, a slurry conveying pipeline 7 is installed in a directional hole 6, and the activated coal gangue slurry is conveyed to an underground coal gangue underground disposal material preparation unit by utilizing the conveying pipeline 7.
The temperature of the calcining equipment 3 is adjustable and controllable, and the temperature range meets the calcining requirement of 500-850 ℃; the internal part of the cabin of the calcining equipment 3 is constantly stirred in a rolling way, so that the fine coal gangue materials can be rapidly and uniformly calcined, the calcining time is determined according to the physical and mechanical properties of required slurry and the leaching toxicity result of the original coal gangue produced by underground coal mining, and the fine coal gangue materials are continuously fed and discharged, so that the supply of the calcined fine coal gangue materials is ensured;
furthermore, the particle grinding equipment 4 is a ball mill and the like, which can ensure that the average particle size of the activated coal gangue micro powder is less than 40 mu m, the particle size of less than 10 mu m accounts for 30-50 percent, and the specific surface area is 3500cm 2 /g～5000cm 2 /g。
In another embodiment of this embodiment, the preparation unit for underground coal gangue disposal material includes an underground coal gangue continuous conveying device 9, an underground coal gangue sorting device 10, an underground crushing device 11, an underground pulping device 12 and a cementing material preparation station 13, which are connected to each other, where the underground coal gangue continuous conveying device 9 is configured to convey coal gangue produced in an underground coal mining working face into the underground coal gangue sorting device 10 for sorting; the underground coal gangue continuous conveying device 9 can be a gangue conveying belt. The underground crushing equipment 11 is used for crushing the sorted coal gangue serving as solid waste to obtain coal gangue aggregate; the gelled material preparation station 13 is communicated with a conveying pipeline 8 in an underground roadway; the cementing material preparation station 13 is used for mixing water glass and an alkaline excitation material, cooling the mixture to prepare an excitation solution, and then mixing the activated coal gangue slurry conveyed by the conveying pipeline 8 in the underground tunnel with the excitation solution to form a coal gangue-based geopolymer cementing material; the underground pulping equipment 12 is used for mixing the coal gangue-based geopolymer cementing material and coal gangue aggregate to prepare the coal gangue underground disposal material.
The underground drilling site and the equipment room 19 are connected with the underground pulping equipment 12 through a slurry conveying pipeline 14, and coal gangue underground disposal materials are filled into the longwall goaf and/or the separation space;
in this embodiment, the downhole crushing plant 11 has built-in crushing, screening and coarse rework systems. And adjusting parameters of a crushing system according to filling requirements, crushing coal gangue, screening gangue aggregates meeting the particle size requirement by using a screening system, and enabling the gangue which does not meet the particle size requirement to reach the crushing system again through a coarse material reworking system for secondary crushing. The coal gangue underground sorting equipment 10, the underground crushing equipment 11, the underground pulping equipment 12 and the cementing material preparation station 13 are all suitable for underground narrow spaces, and the input and output of all materials are continuous processes. Meanwhile, the underground coal gangue continuous conveying device is in a sealed environment, so that underground dust is prevented.
Example 2
The embodiment discloses an underground disposal method of all coal gangue on the basis of embodiment 1, and the underground disposal method of all coal gangue is carried out by adopting the underground-aboveground linkage coal gangue disposal system in embodiment 1, and comprises the following steps:
determining the coal gangue disposal amount of the longwall goaf according to the total void fracture space amount of the longwall goaf, selecting a grouting hole of the longwall goaf, and filling the coal gangue underground disposal material into the longwall goaf through the grouting hole of the longwall goaf according to the coal gangue disposal amount of the longwall goaf;
and/or selecting a grouting layer position of a separation space, determining the coal gangue disposal amount of the separation space according to the maximum limit injection-production ratio of the separation space, and sequentially filling the coal gangue underground disposal materials into the grouting layer position of the separation space according to the coal gangue disposal amount of the separation space according to a grouting sequence;
the filling speed of the coal gangue underground disposal material is larger than or equal to the coal gangue production speed. The above-mentioned filling is performed in particular from the underground drill site and equipment room 19 through the grouting pipe 15.
In a preferred embodiment of this embodiment, specifically, the total amount of the void fracture space of the longwall gob is determined by the following formula:
V＝λ×2L×l t ×h m
wherein V is the total amount of the space of the gap and the crack of the longwall goaf, and the unit is m 3 (ii) a L is the limit collapse distance, and the unit is m; h is a total of m The unit is m for the mining height of the coal bed; l t Advancing length for coal mining in units of m; lambda is a time factor, and 0.95 is taken when the coal is just mined; within 1 year of mining time, taking 0.9-0.4; mining for 1 to 3 years, and taking 0.4 to 0.3; mining for more than 3 years, and taking 0.3-0.25;
specifically, the limit collapse distance L is determined by the following formula:
L＝3×min{L t ,L s ,L y }
wherein L is t The limit span is formed under the action of bending moment when the old top beam is broken, and the unit is m; l is s The limit span is formed under the action of shear stress when the old top beam is broken, and the unit is m; l is y Is a reality ofThe monitored periodic pressure step is m. The specific calculation is L t ,L s ,L y The minimum value of the three values is taken and then multiplied by 3, and the ultimate collapse distance is obtained.
The limit span L formed under the action of bending moment when the old top beam is broken t Calculated by the following formula:
the limit span L formed under the action of shear stress when the old top beam is broken s Calculated by the following formula:
wherein σ t Is the basic roof rock tensile strength in kPa; sigma s Is the basic roof rock shear strength in kPa; h is the base top thickness in m; q is the load uniformly distributed on the top of the basic roof, and the unit is kPa;
the substantially top uniform load q is calculated by the following formula:
wherein, γ i Is the weight of each stratum at the top of the base layer and has the unit of N/m 3 ；h i Is the thickness of each layer of rock formation substantially on top, in m;
is the average weight of the basic top overburden stratum and has the unit of N/m 3 ；h c Is the base top overburden thickness in m.
Further, the grouting holes of the selected longwall goaf comprise directional construction grouting holes with the goaf, which is formed in the longwall mining process and is 1-2 m away from the end of the isolation coal pillar, as a target point;
the coal gangue disposal amount of the longwall goaf comprises the coal gangue disposal amount of the longwall goaf determined according to the coal gangue proportion in the filled coal gangue underground disposal material and the total amount of the void fracture space of the longwall goaf.
In a preferred embodiment of this embodiment, specifically, selecting a grouting level of the delamination space includes the following steps:
step 1, judging the rigidity of a rock stratum according to a drilling histogram, preliminarily judging a strong bearing rock stratum, and determining a plurality of key layers in the rock stratum; the key layers include a main key layer and a sub-key layer. Referring to fig. 3-4, there is one main critical layer 24 and two sub-critical layers, sub-critical layer two 26 and sub-critical layer one 27.
Step 2, calculating the breaking distance of each key layer in the plurality of key layers;
step 3, selecting a layer with a final hole layer position located above the comprehensive height top boundary of the water flowing fractured zone and larger than 20m and a limit mining width corresponding to the breaking distance of the key layer and larger than the width of the grouting filling working face from the plurality of key layers as a grouting layer position;
if the selected grouting layer position is one, grouting in the grouting layer position; and if the selected grouting positions are multiple, sequentially grouting the multiple grouting positions according to the descending order of the breaking distance value of each key layer.
By comparing the breaking distance value of the key layer, the smaller the breaking distance value of the key layer is, the rock stratum can be broken first, and the broken key layer does not generate a separation space, so that grouting is performed first.
Breaking distance L of the key layer x Calculated from the following formula:
wherein: h is x The thickness of the key layer of the x layer is m; sigma tx The tensile strength of the key layer of the x layer is expressed in kPa; q. q.s x The unit of the load borne by the key layer of the x layer is kPa;
the limit mining width corresponding to the breaking distance of the key layer is calculated by the following formula:
wherein s is the limit mining width corresponding to the breaking distance of the key layer and the unit is m; l is x The breaking distance of the key layer is m; h is the distance between the key layer and the mining coal bed and the unit is m; delta is the fracture angle of the overlying strata of the coal seam, and the unit is DEG;
and the width w of the grouting filling working face of the separation space is smaller than the limit mining width s corresponding to the breaking distance of the key layer.
The comprehensive height of the water-flowing fractured zone is comprehensively determined according to the height of a theoretical water-flowing fractured zone and the height of an actual water-flowing fractured zone, the height of the theoretical water-flowing fractured zone is calculated and determined according to a related formula of a procedure (a coal pillar setting and coal pressing mining procedure of buildings, water bodies, railways and main headings), and the height of the actual water-flowing fractured zone is determined according to the leakage amount of a drilling flushing fluid on site and a drilling television peeking method.
Further, the maximum limit injection-production ratio of the separation space is calculated by the following formula:
in the formula: alpha is the maximum limit injection-production ratio of the separation space; s is the limit mining width corresponding to the breaking distance of the key layer, and the unit is m; h z The distance between the grouting filling section and the coal seam is m; h is m The unit is m for the mining height of the coal bed; phi is the full mining angle, and the unit is DEG; h c The height of the caving zone is m; k' p The residual crushing and swelling coefficient of the goaf is 1.03-1.05; xi is the limiting coefficient of the reasons of the grouting filling system, filling and mining matching and the like, and is takenThe value range is 0.6 to 0.8.
The actual value of the width w of the grouting filling working face is smaller than the limit mining width s corresponding to the breaking distance of the key layer, so that the actual injection-production ratio is smaller than the calculated maximum limit injection-production ratio.
The actual injection-production ratio of the separation space is calculated by the following formula:
α s and w is the actual injection-production ratio of the separation space, the width of a grouting filling working surface is w less than s, and the unit is m.
Determining the coal gangue disposal amount of the separation space according to the maximum limit injection-production ratio of the separation space, namely determining the coal gangue disposal amount of the separation space according to the actual injection-production ratio alpha s And the coal mining volume (known amount) in the working face to obtain the volume of the compacted ash body filled in the overlying rocks, wherein the volume of the compacted ash body filled in the overlying rocks is equal to the groutable space of the separation space, namely the volume of the coal gangue underground disposal material of the separation space. The density of the coal gangue underground disposal material is determined by using a test method, and the disposal quantity of the coal gangue in a separation space can be obtained by combining the mass ratio of the coal gangue in the coal gangue underground disposal material.
In the embodiment, the coal gangue underground disposal material is conveyed to an underground gap fracture space by an underground conveying pipeline in a pumping mode, so that the coal gangue underground disposal material and a loose accumulation body in a goaf form cementation, on one hand, the coal gangue in the mining process is disposed in real time, the coal gangue is prevented from being infiltrated by coal gangue pollutants generated after being soaked by underground water in a high-ground-stress environment for a long time to cause underground water pollution, and on the other hand, a cementation and solidification supporting top plate is formed in the goaf to prevent surface subsidence.
Further, as shown in fig. 5, a coal gangue underground disposal material grouting pipe 1-1 can be preset before the underground coal mining working face is pushed, the end of the grouting pipe is sealed, an automatic control valve 1-2 is arranged in the pipeline at a certain distance, the grouting amount is calculated according to the size of the working face, the coal seam mining height and the collapse and expansion coefficient, the real grouting amount is calculated by using the diameter of the grouting pipeline and the grouting time, and the control valves are opened from far to near in sequence to gradually fill the gap and crack space of the goaf.
Furthermore, a directional drilling method can be selected to construct a directional grouting hole, and the coal gangue underground disposal material is conveyed to the gap fracture space by using the directional grouting hole to dispose the coal gangue being mined.
The method for underground disposal of the full coal gangue obtains the coal gangue yield 1728m according to the coal mining advancing speed of 6 m/day, the working face width of 240m, the coal seam mining height of 6m and the coal gangue proportion of 20 percent in the coal mining process 3 The day is. Selecting proper underground coal gangue sorting and crushing equipment, matching corresponding coal gangue underground disposal material slurry conveying pipelines, and reasonably selecting the number of grouting holes and grouting flow rate by combining determined coal gangue disposal amount, coal mining propulsion speed, underground coal gangue sorting and crushing capacity and coal gangue underground disposal material slurry pipeline conveying capacity, wherein the filling speed when filling the coal gangue underground disposal material is more than or equal to coal gangue generation speed, temporary accumulation of underground coal gangue is reduced, and coal gangue lift-up is avoided.
In the embodiment, the activated coal gangue powder rich in the aluminosilico-silicate mineral in the coal gangue underground disposal material and the coal gangue aggregate are mixed according to the mass ratio of 1 (1-4);
the coal gangue-based geopolymer cementing material comprises the following components in percentage by mass: 200-300 parts of activated coal gangue powder rich in silicon-aluminum minerals, 20-40 parts of water glass, 5-10 parts of alkaline excitation materials and 120-900 parts of water;
the activated coal gangue powder rich in the silicon-aluminum mineral is prepared by crushing coal gangue through crushing equipment to make the particle size of the coal gangue smaller than 5mm, and adding Na into the coal gangue particles with the particle size smaller than 5mm 2 CO 3 After the powder is stirred, the mixture is calcined for 0.5 to 4 hours at the high temperature of between 500 and 850 ℃ for decarburization activation, and then ball milling is carried out by a ball mill to obtain the product with the average grain diameter of less than 40 mu m and the specific surface area of between 3500 and 5000cm 2 Activated coal gangue powder per gram, wherein the activated coal gangue powder with the particle size of less than 10 mu m accounts for 30-50 percent;
Na 2 CO 3 the mixing amount of the powder is 3 per mill of the mass of coal gangue particles smaller than 5 mm;
the modulus of the water glass is 1.0-1.3;
the alkali excitation material comprises one or more of sodium hydroxide, potassium hydroxide or quicklime;
the coal gangue aggregate is coal gangue with the maximum grain diameter of 5-20 mm after the coal gangue is crushed.
This example presents a preferred solution: the width of a certain working face of a certain mine is 240m, and the coal mining advancing length is l t 3000m, the coal seam mining height is 6m, the main key layer is sandy mudstone, the layer thickness is 49m, the overlying load borne by the main key layer is 2.0MPa, and the tensile strength of the main key layer is 2.37MPa.
In this example, the total amount of void fracture space in the longwall gob is calculated as follows:
according to the measured data, the tensile strength of the basic roof rock is 4.03MPa, the shear strength is 6.2MPa, the basic roof thickness h is 15m, and the average density of the overlying strata is 2400kg/m 3 And the thickness of the top cover rock layer is 296.3m.
Calculated limit span L formed under the action of bending moment t ＝13.03m；
Limit span L formed under shear stress s ＝17.44m
Periodic pressure L in coal mining process y Is 15m.
And (3) synthesizing the ultimate span and period pressure results under the action of bending moment and shearing stress, and determining that the ultimate collapse distance L is 39m. The minimum of the three is multiplied by 3=13 × 3=39m.
Calculating the void fracture space V =0.95 × 2 × 39 × 6 × 3000=1333800m of the longwall gob 3
The usage amount of the coal gangue underground disposal material is determined according to the total amount of the void fracture space of the longwall goaf, and the coal gangue disposal amount of the longwall goaf is determined according to the coal gangue proportion and the coal gangue underground disposal material density in the filled coal gangue underground disposal material. The method comprises the following specific steps:
the total space amount of the gap and the crack of the longwall goaf is 1333800m 3 Amount of coal gangue used as underground materialIs 1333800m 3 The mass ratio of the coal gangue to the underground coal gangue disposal material is 62.5-66.7%; the density of the coal gangue underground disposal material is known to be 1750-2350 kg/m 3 (ii) a The disposal quantity of the coal gangue is 1 458 843.75 to 2 090 664.81t.
The gangue output of the working face is known to be 864 000m 3 The average density of the coal gangue is about 1700-1800 kg/m 3 The output quality of the coal gangue on the working face is 1 468 to 1 555 200t, and the disposal quantity of the coal gangue is equal to or less than the disposal quantity of the coal gangue in a gap crack space formed by the working face, which shows that enough goaf gap crack space can carry out underground cooperative disposal on the coal gangue produced by mining on the working face, the coal gangue can be filled along with mining on the same working face, and the coal gangue in the adjacent working face can be disposed by using the residual crack space.
In this embodiment, in step 2 of selecting the grouting horizon of the separation space, the maximum value of the breaking distance of the key layer is selected for filling by calculating the breaking distances of a plurality of key layers. Calculating the breaking distance L of the maximum key layer x ＝75.4m；
Meanwhile, the distance H between the key layer and the mining coal layer is 163m, and the fracture angle delta of the overlying strata of the coal layer is 62 degrees, so that the limit mining width s corresponding to the fracture distance of the maximum key layer is calculated by a formula to be s =248.8m, and the width w of the grouting filling working face of the off-bed space is smaller than the limit mining width s corresponding to the fracture distance of the key layer.
In the step 3, the total thickness of the coal seam is known to be 6m, the overlying strata is a medium-hard top plate, the height of a theoretical water flowing fractured zone is 39.8-51.0 m, and the corresponding fracturing-mining ratio is 6.6-8.5. According to the on-site drilling washing liquid leakage and the drilling television comprehensive result, the method comprises the following steps: the height of the actual water flowing fractured zone is 106-121 m, and the fracture production ratio is 17.7-20.2.
Therefore, the comprehensive height of the water-flowing fractured zone is comprehensively determined to be below 121m according to the height of the theoretical water-flowing fractured zone and the height of the actual water-flowing fractured zone.
In order to prevent the separation zone from being communicated with the water flowing fractured zone during grouting, a safety distance of more than 20m, namely more than 141m, is reserved between the grouting layer and the top boundary of the water flowing fractured zone, and the key layer is located 163m above the coal bed, meets the requirements and can be used as the grouting layer.
Obtaining the comprehensive result according to the leakage amount of the flushing liquid for drilling on site and the drilling television: height of caving zone H c 19.13m, coal mining height h m 6.0m, the width w of the grouting filling working face is 240m, and the distance H between the main grouting filling section and the coal seam z 163m, a full mining angle phi of 53 degrees and a gob residual crushing expansion coefficient K' p Taking 1.03, taking the limiting coefficient xi of the reasons of grouting filling system, filling and mining matching and the like as 0.75, substituting the limiting coefficient xi into a formula to calculate the actual injection-mining ratio alpha of the separation space s ＝33.1％。
The coal gangue emission is known to account for about 10% -20% of the coal output, and the injection-production ratio is calculated to be 33.1% and is far more than 20%. The coal gangue is filled into the separation space, and the coal gangue can be filled along with mining.
Actual injection-production ratio alpha s (33.1%) is less than the calculated maximum limiting voidage replacement ratio alpha (34.34%). According to the actual injection-production ratio alpha s And the coal extraction volume in the working face to obtain the volume of the compacted ash body, namely the volume of the coal gangue underground disposal material. The density of the coal gangue underground disposal material is determined by using a test method, and the disposal quantity of the coal gangue in a separation space can be obtained by combining the mass ratio of the coal gangue in the coal gangue underground disposal material. The method comprises the following specific steps:
the volume of the coal gangue underground disposal material is 33.1 percent multiplied by 240 multiplied by 6 multiplied by 3000=1429920m 3 ；
The mass ratio of the coal gangue to the underground coal gangue disposal material is 62.5-66.7%;
the density of the coal gangue underground disposal material is 1750-2350 kg/m 3 ；
The disposal quantity of coal gangue in the separation space is 1 563 975-2 241 328.1t.
The output quality of the coal gangue on the working face is 1 468 800-1 555 200t, and the coal gangue disposal quantity is smaller than the separation space, which indicates that enough separation space is available for underground cooperative disposal of the coal gangue produced by mining the working face, the coal gangue can be filled along with mining on the same working face, and the coal gangue in the adjacent working face can be disposed by using the residual fracture space.
Example 3
In this example, on the basis of example 2, the specific mixture ratio of the coal gangue underground disposal material and the performance data thereof are given.
Proportioning 1: the activated coal gangue powder rich in the aluminosilico-silicate mineral in the coal gangue underground disposal material and the coal gangue aggregate are in a mass ratio of 1 (1-4), wherein the coal gangue-based geopolymer cementing material comprises the following components in percentage by mass: 200 parts of activated coal gangue powder rich in silicon-aluminum minerals, 1.0 and 28 parts of water glass modulus, 5 parts of NaOH and 210 parts of water. 200 parts of coal gangue aggregate.
Further, calcining for 0.5h at 600 ℃ in a high-temperature device for decarburization and activation. The water is common tap water or mine water after treatment, has good water quality, does not contain heavy metal and harmful components, meets the national underground water standard, and does not pollute underground water.
The difference between the mixture ratio 2 and the mixture ratio 1 is as follows: the coal gangue-based geopolymer cementing material comprises the following components in percentage by mass: 250 parts of activated coal gangue powder rich in silicon-aluminum minerals, 1.1 parts of water glass modulus, 32 parts of NaOH 8 parts and 380 parts of water. 500 parts of coal gangue aggregate.
The difference between the mixture ratio 3 and the mixture ratio 1 is as follows: the coal gangue-based geopolymer cementing material comprises the following components in percentage by mass: 300 parts of activated coal gangue powder rich in silicon-aluminum minerals, 1.3 parts of water glass modulus, 20 parts of NaOH 10 parts and 750 parts of water. 1200 parts of coal gangue aggregate.
The ratio 4 is different from the ratio 1 in that: the coal gangue-based geopolymer cementing material comprises the following components in percentage by mass: 200 parts of activated coal gangue powder rich in silicon-aluminum minerals, 1.0 and 30 parts of water glass modulus, 7 parts of KOH and 350 parts of water. 450 parts of coal gangue aggregate.
The ratio 5 is different from the ratio 1 in that: the coal gangue-based geopolymer cementing material comprises the following components in percentage by mass: 250 parts of activated coal gangue powder rich in silicon-aluminum minerals, 1.1 and 28 parts of water glass modulus, 8 parts of KOH and 500 parts of water. 750 parts of coal gangue aggregate.
The mixture ratio 6 is different from the mixture ratio 1 in that: the coal gangue-based geopolymer cementing material comprises the following components in percentage by mass: 300 parts of activated coal gangue powder rich in silicon-aluminum minerals, 1.2 parts of water glass modulus, 25 parts of KOH 9 parts and 650 parts of water. 900 parts of coal gangue aggregate.
The difference between the mixture ratio 7 and the mixture ratio 1 is as follows: the coal gangue-based geopolymer cementing material comprises the following components in percentage by mass: 200 parts of activated coal gangue powder rich in silicon-aluminum minerals, 1.0 part of water glass modulus, 30 parts of CaO 5 parts of water and 220 parts of water. 200 parts of coal gangue aggregate.
The difference between the mixture ratio 8 and the mixture ratio 1 is as follows: the coal gangue based geopolymer cementing material comprises the following components in percentage by mass: 250 parts of activated coal gangue powder rich in silicon-aluminum minerals, 1.0 part of water glass modulus, 30 parts of CaO 8 parts of water and 380 parts of water. 500 parts of coal gangue aggregate.
The properties of the all-coal gangue underground disposal material obtained by different mass parts are shown in the table below, and the material injected into the gap fracture space has cementation property, generates certain strength and prevents the overlying rock stratum from being suddenly broken.
TABLE 1 properties of coal gangue underground disposal materials obtained by different mass portion ratios
The invention has the advantages that: (1) The coal gangue hill on the ground and the underground coal gangue which is being produced can be simultaneously treated, so that the gangue can not rise into the well and can be treated on the surface of the ground; (2) The self-activity of the coal gangue is effectively excited by utilizing the self-characteristics of the coal gangue to prepare the cementing material, the in-situ crushed coal gangue aggregate can be wrapped and cured to form aggregate slurry, so that underground water pollution caused by infiltration of pollutants caused by the coal gangue in a high ground stress environment for a long time can be prevented, the advantage of maximally utilizing the disposal of the coal gangue by replacing the doping of cement can be realized, and the method has a huge popularization and application prospect; (3) The coal gangue underground disposal material is filled into the goaf, so that the broken rock mass in the goaf can be solidified, a top plate is supported, and the problem that the ecological environment is damaged due to surface subsidence caused by overlying strata settlement of the goaf is solved. (4) Filling coal gangue underground disposal materials into the separation space can prevent the main key layer from being broken and can also prevent the ecological environment problem caused by surface subsidence.
Claims (10)
1. The underground-aboveground linkage coal gangue disposal system comprises an aboveground active coal gangue slurry preparation unit and an underground coal gangue disposal material preparation unit, and is characterized in that the aboveground active coal gangue slurry preparation unit is communicated with the underground coal gangue disposal material preparation unit, the aboveground active coal gangue slurry preparation unit is used for transporting prepared active coal gangue slurry to the underground coal gangue disposal material preparation unit, and the underground coal gangue disposal material preparation unit is used for preparing underground coal gangue disposal materials and filling and disposing long-wall goafs and/or separation layer spaces;
the aboveground active coal gangue slurry preparation unit comprises an aboveground crushing device (2), a calcining device (3), a particle grinding device (4), an aboveground pulping device (5) and a conveying pipeline (7) which are connected; the aboveground crushing equipment (2) is used for crushing ground coal gangue to obtain coal gangue fine materials; the calcining equipment (3) is used for calcining the coal gangue fine materials and then conveying the calcined coal gangue fine materials to the particle grinding equipment (4); the particle grinding equipment (4) is used for decarbonizing and activating the calcined coal gangue fine materials to form activated coal gangue powder; the aboveground pulping equipment (5) is used for mixing the activated coal gangue powder with water to obtain active coal gangue slurry; the conveying pipeline (7) is used for conveying the active coal gangue slurry to a preparation unit of underground coal gangue disposal materials;
the underground coal gangue underground disposal material preparation unit comprises an underground coal gangue continuous conveying device (9), coal gangue underground sorting equipment (10), underground crushing equipment (11), underground pulping equipment (12) and a cementing material preparation station (13) which are connected;
the underground coal gangue continuous conveying device (9) is used for conveying coal gangue generated on an underground coal mining working face to the coal gangue underground sorting equipment (10) for sorting; the underground crushing equipment (11) is used for crushing the coal gangue which is separated by the coal gangue underground separation equipment (10) and is used as solid waste to obtain coal gangue aggregate; the cementing material preparation station (13) is communicated with the conveying pipeline (7) through a conveying pipeline (8) in an underground roadway; the cementing material preparation station (13) is used for mixing water glass and an alkaline excitation material, cooling the mixture to prepare an excitation solution, and mixing the active coal gangue slurry conveyed by the conveying pipeline (8) in the underground roadway with the excitation solution to form a coal gangue-based geopolymer cementing material; the underground pulping equipment (12) is used for mixing the coal gangue-based geopolymer cementing material and the coal gangue aggregate to prepare a coal gangue underground disposal material.
2. The system for disposing the coal gangue linkage underground-aboveground according to the claim 1, further comprising an underground drill site and an equipment room (19), wherein the underground drill site and the equipment room (19) are connected with the underground pulping equipment (12) through a slurry conveying pipeline (14), and the underground disposal material of the coal gangue is filled into a longwall goaf and/or a separation space;
the particle grinding equipment (4) is a ball mill; the underground crushing equipment (11) is internally provided with a crushing system, a screening system and a coarse material reworking system.
3. An underground disposal method for all coal gangue, which is characterized in that the underground disposal method for all coal gangue by adopting the underground-aboveground linkage coal gangue disposal system as claimed in any one of claims 1-2 comprises the following steps:
determining the coal gangue disposal amount of the longwall goaf according to the total void fracture space amount of the longwall goaf, selecting a grouting hole of the longwall goaf, and filling the coal gangue underground disposal material into the longwall goaf through the grouting hole of the longwall goaf according to the coal gangue disposal amount of the longwall goaf;
and/or selecting a grouting layer position of the separation layer space, determining the coal gangue disposal amount of the separation layer space according to the maximum limit injection-production ratio of the separation layer space, and sequentially filling the coal gangue disposal materials into the grouting layer position of the separation layer space according to the coal gangue disposal amount of the separation layer space according to a grouting sequence;
and the filling speed of filling the coal gangue underground disposal material is greater than or equal to the coal gangue generation speed.
4. The underground disposal method of full coal gangue as claimed in claim 3, wherein the total amount of void fracture space of the longwall gob is determined by the following formula:
V＝λ×2L×l t ×h m
wherein V is the total amount of the void and crack space of the longwall gob, and the unit is m 3 (ii) a L is the limit collapse distance, and the unit is m; h is a total of m The unit is m for the mining height of the coal bed; l. the t Advancing length for coal mining in units of m; lambda is a time factor, and 0.95 is taken when the coal is just mined; within 1 year of exploitation, taking 0.9-0.4; mining for 1 to 3 years, and taking 0.4 to 0.3; mining for more than 3 years, and taking 0.3-0.25;
the limit collapse distance L is determined by the following formula:
L＝3×min{L t ,L s ,L y }
wherein L is t The limit span is formed under the action of bending moment when the old top beam is broken, and the unit is m; l is s The limit span is formed under the action of shear stress when the old top beam is broken, and the unit is m; l is a radical of an alcohol y Is the actual monitored cycle step size in m.
5. The underground disposal method for all-coal gangue according to claim 4, wherein the limit span L formed under the action of bending moment when the old roof beam breaks is formed t Calculated by the following formula:
limit span L formed under the action of shear stress when the old top beam is broken s Calculated by the following formula:
wherein σ t Is the basic roof rock tensile strength in kPa; sigma s Is the basic roof rock shear strength in kPa; h is the base top thickness in m; q is the load uniformly distributed on the top of the basic part, and the unit is kPa;
the substantially top uniform load q is calculated by:
wherein, gamma is i Is the weight of each stratum at the top of the base layer and has the unit of N/m 3 ；h i Is the thickness of each stratum at the top of the base layer and has the unit of m;
is the average weight of the basic top overburden rock layer and has the unit of N/m 3 ；h c Is the thickness of the basic roof overburden, and the unit is m; the value range of i is a positive integer from 1 to n.
6. The underground disposal method of all-coal gangue as claimed in claim 3, wherein the selecting of the grouting holes of the longwall goaf comprises directional construction of the grouting holes with the goaf, which is located 1-2 m away from the end of the isolation coal pillar, in the goaf formed during longwall mining as a target;
the coal gangue disposal amount of the longwall goaf comprises the coal gangue disposal amount of the longwall goaf determined according to the coal gangue proportion in the filled coal gangue underground disposal material and the total amount of the void fracture space of the longwall goaf.
7. The underground disposal method for the full coal gangue according to the claim 3, wherein the selection of the grouting horizon of the separation space comprises the following steps:
step 1, judging the rock stratum rigidity according to a drilling histogram, preliminarily judging a strong bearing rock stratum, and determining a plurality of key layers in the rock stratum;
step 2, calculating the breaking distance of each key layer in the plurality of key layers;
step 3, selecting a layer, as a grouting layer, of which the final pore layer is positioned above the comprehensive height top boundary of the water flowing fractured zone and is more than 20m, and the breaking distance of the key layer corresponds to a layer with the ultimate mining width larger than the width of a grouting filling working face;
if the selected grouting layer position is one, grouting in the grouting layer position; and if the selected grouting positions are multiple, sequentially grouting the multiple grouting positions according to the sequence of the breaking distance value of each key layer from small to large.
8. The underground all-coal gangue disposal method according to claim 7, wherein the breaking distance L of the key layer x Calculated from the following formula:
wherein: h is x The thickness of the key layer of the x layer is m; sigma tx The tensile strength of the key layer of the x layer is expressed in kPa; q. q of x The unit of the load borne by the key layer of the x layer is kPa; the value range of x is a positive integer from 1 to n;
the limit mining width corresponding to the breaking distance of the key layer is calculated by the following formula:
wherein s is the pole corresponding to the breaking distance of the key layerLimited mining width in m; l is a radical of an alcohol x The breaking distance of the key layer is m; h is the distance between the key layer and the mined coal bed and the unit is m; and delta is the fracture angle of the overlying strata of the coal bed and has the unit of.
9. The underground disposal method of full coal gangue as claimed in claim 4, wherein the maximum limit injection-production ratio of said separation space is calculated by the following formula:
in the formula: alpha is the maximum limit injection-production ratio of the separation space; s is the limit mining width corresponding to the breaking distance of the key layer, and the unit is m; h z The distance between the grouting filling section and the coal seam is m; h is a total of m The unit is m for the mining height of the coal bed; phi is a full mining angle, and the unit is DEG; h c The height of the caving zone is m; k' p The residual crushing and swelling coefficient of the goaf is 1.03-1.05; xi is the limiting coefficient of the grouting filling system, filling and mining matching and the like, and the value range is 0.6-0.8.
10. The underground disposal method of all-coal gangue according to claim 3, wherein the activated coal gangue powder rich in aluminosilico minerals in the underground disposal material of coal gangue and the aggregate of coal gangue are mixed according to the mass ratio of 1 (1-4);
the coal gangue based geopolymer cementing material comprises the following components in percentage by mass: 200-300 parts of activated coal gangue powder rich in silicon-aluminum minerals, 20-40 parts of water glass, 5-10 parts of alkali excitation materials and 120-900 parts of water;
the activated coal gangue powder rich in the silicon-aluminum mineral is prepared by crushing coal gangue through crushing equipment to ensure that the particle size of the coal gangue is less than 5mm, and adding Na into coal gangue particles with the particle size of less than 5mm 2 CO 3 After the powder is stirred, the mixture is calcined for 0.5 to 4 hours at a high temperature of between 500 and 850 ℃ for decarburization and activation, and then is ball-milled by a ball mill to obtain the product with the average grain diameter of less than 40 mu m,the specific surface area is 3500-5000 cm 2 The activated coal gangue powder per gram, wherein the activated coal gangue powder with the grain diameter of less than 10 mu m accounts for 30-50 percent;
the Na is 2 CO 3 The mixing amount of the powder is 3 per mill of the mass of coal gangue particles smaller than 5 mm;
the modulus of the water glass is 1.0-1.3;
the alkali excitation material comprises one or more of sodium hydroxide, potassium hydroxide or quicklime;
the coal gangue aggregate is coal gangue with the maximum grain diameter of 5-20 mm after the coal gangue is crushed.
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| CN112343651A (en) * | 2020-06-24 | 2021-02-09 | 山东恒驰矿业装备科技有限公司 | Process and equipment for filling mining by using coal gangue |
| CN213928441U (en) * | 2021-05-08 | 2021-08-10 | 兰州资源环境职业技术学院 | Complete equipment for backfilling from top to bottom of well suitable for promoting ecological management in mine area waste rock treatment |
| CN113565510B (en) * | 2021-07-05 | 2023-08-04 | 太原理工大学 | Ultra-thick coal seam fully mechanized filling mining method based on underground gangue pile |
| CN113716917A (en) * | 2021-09-08 | 2021-11-30 | 河北建筑工程学院 | Preparation method of coal gangue coarse aggregate concrete |
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