CN101439950B - Flexible coal powder foam concrete and preparation thereof - Google Patents

Flexible coal powder foam concrete and preparation thereof Download PDF

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Publication number
CN101439950B
CN101439950B CN2008102369392A CN200810236939A CN101439950B CN 101439950 B CN101439950 B CN 101439950B CN 2008102369392 A CN2008102369392 A CN 2008102369392A CN 200810236939 A CN200810236939 A CN 200810236939A CN 101439950 B CN101439950 B CN 101439950B
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China
Prior art keywords
concrete
coal
mode
water
flexible
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Expired - Fee Related
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CN2008102369392A
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Chinese (zh)
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CN101439950A (en
Inventor
汪海滨
李小春
崔银祥
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Wuhan Institute of Rock and Soil Mechanics of CAS
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Wuhan Institute of Rock and Soil Mechanics of CAS
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    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474Uses not provided for elsewhere in C04B2111/00
    • C04B2111/00724Uses not provided for elsewhere in C04B2111/00 in mining operations, e.g. for backfilling; in making tunnels or galleries
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/70Grouts, e.g. injection mixtures for cables for prestressed concrete

Abstract

The invention discloses a flexible coal dust foam concrete and a method for preparing the same, and in particular relates to a concrete. The concrete comprises the following main components by weight percentage: 10 to 15 percent of cement; 35 to 65 percent of coal dust; 20 to 45 percent of medium coarse sand; 3 to 4.5 percent of water; 0.1 to 0.3 percent of waterproofing agent; and 1 to 1.5 percent of foaming agent. A mode for blocking the wall surface of a heading by using the concrete is a concrete spraying mode, or a concrete lining mode, or a concrete curtain grouting mode. The flexible coal dust foam concrete is prepared from local materials, makes full use of the coal dust accumulated in the heading by underground drilling to reduce the transportation and construction cost of a supporting material and improve the efficiency and the progress of coal mining excavation, and has small impoverishment effect on coal products; a structural body has excellent impermeability, good leakproofness and integrity; besides, the concrete can be widely used for blocking and preventing seepage for the wall surface of a gas displacement coal-bed methane gas tunnel in coal mines, and also can be applied to supporting surrounding rocks of complex rock stratums or other dynamic pressure tunnels with the characteristics of softness, expansion, rheological performance and the like.

Description

Flexible coal powder foam concrete and preparation method thereof
Technical field
The present invention relates to a kind of concrete, relate in particular to a kind of flexible coal powder foam concrete and preparation method thereof.
Background technology
The gas displacing coal-bed technology of gas is to coal seam injecting gas (CO by boring 2, nitrogen, air, stack gas etc.), utilize that injecting gas is replaced, driven, pressurize and anatonosis effect, promote the coal-seam gas desorption and drive coal-seam gas to flow to extraction borehole.The gas displacing coal-bed technology of gas can increase substantially the gas recovery ratio, has control gas disaster, reduces drawing-off gas, improves the gas utilization rate, increases the multiple effect of coal mining efficient, has important practical significance and long-range strategic importance.
The migration of gas in coal body needs two conditions, i.e. the existence of pressure difference and crack passage.The gas pressure difference has constituted the power that gas is migrated in coal body; The crack passage has constituted the passage that gas is migrated in coal body.Increase the flow of gas in coal body, answer intensified pressure poor on the one hand, then should increase the ventilation property in coal seam on the other hand; And improve the extraction negative pressure, be limited (because its ultimate value can only reach 0.1MPa, moreover improve the extraction negative pressure requirement of extraction equipment is also increased, thereby be subjected to certain restriction) to the increase of gas pressure difference in the coal seam.
The gas displacing coal-bed test in place of existing gas shows that the coal seam is very broken around the tunnel, and extraction hole sealing of hole is not tight, and air flows into the extraction hole by the crack.A large amount of inclusion of air have reduced gas density, have reduced gas flow, influence the displacement effect; On the other hand, coal mining causes the mined bed terrestrial stress to discharge, and the lax formation fracture that causes in stratum provides passage for Gas Flow, makes gas can move to coal-face.Under virgin state, the pressure of the pressure ratio coal mine work area of gas wants high in the coal, and the pressure of general coal mine work area is near normal atmosphere.Therefore, when Tunnel Pressure descended, gas can flow to around the coal mine work area.Being exploited turbulent influences, and the gas source of disturbed area will discharge a part of gas, flows to coal-face.
As seen, the shutoff tunnel wall of taking measures is the key that improves the displacement effect.Consider that driving and back production have certain time difference, take into account the tunnel and stablize the supporting needs temporarily, solution route then is to the sealing of exploitation exposure, as adopt lining cutting, or combined bolting and shotcrete [is the sprayed concrete+anchor pole (rope) of aggregate with the sandstone material], or, form certain thickness anti-seepage reinforcing wall to the inner slip casting in relaxation zone coal seam, tunnel.But above-mentioned measure is for entry, and the wall supporting of shutoff tunnel must cause interference to exploitation, dilution coal seam quality.And underground coal mine often transports difficulty, and for conventional support process, the shutoff cost is higher, and disturbs the progress of driving or exploitation.In the tunneling process, down-hole drilling coal dust bulk deposition is if can make full use of then achieve many things at one stroke.
Therefore, develop a kind of novel flexible plugging material, adopt mould to build that modes such as cast-in-place, injection or slip casting are reinforced and shutoff coal mine roadway wall is very necessary.
Summary of the invention
Purpose of the present invention just is to overcome the problem and shortage that prior art exists, and a kind of flexible coal powder foam concrete and preparation method thereof is provided.
The object of the present invention is achieved like this:
The coal dust that directly utilizes coal mine down-hole drilling and produced is as aggregate, by cement as gelling material, by whipping agent and water-resisting agent as main additive.
One, this concrete main ingredient
By weight percentage
Cement 10~15;
Coal dust 35~65;
Medium coarse sand 20~45;
Water 3~4.5;
Water-resisting agent 0.1~0.3;
Whipping agent 1~1.5.
Checking:
* all components lower limit sum is less than 100%, and all components upper limit sum is greater than 100%;
* the lower limit of each component adds the upper limit sum of other component greater than 100%;
* the upper limit of each component adds the lower limit sum of other component less than 100%.
Two, this concrete preparation method
This concrete preparation method comprises the following steps:
1. with coal dust and medium coarse sand from on-site sampling, measure water ratio, content that should corresponding minimizing water;
2. cement, coal dust and medium coarse sand are poured into stirrer and mixed stirring 4~6 minutes;
3. get mixed solvent after water, water-resisting agent and whipping agent being mixed, and place the water tank that adds that stirs pusher side;
4. the limit adds the fiber limit and stirs in the mixture of 2. cement, coal dust and medium coarse sand, to full and uniform;
5. the mixed solvent that adds 3. water, water-resisting agent and whipping agent, restir promptly gets a kind of flexible coal powder foam concrete to full and uniform.
The present invention has following advantage and positively effect:
1. gather materials on the spot, make full use of down-hole drilling and be deposited in coal dust in the tunnel, reduce the transportation and the construction cost of support material, improve the efficient and the progress of coal mining driving, little to coal product dilution influence.
2. this concrete can by spray, mode such as cast-in-place or slip casting finishes, expansion is strong, has very low Young's modulus and good viscous deformation, and is bonding firmly with the tunnel wall, guarantee enough mechanical strengths and with well-formed's cooperative transformation ability;
3. the structure impermeability is good, and stopping property that tool is good and integrity play sealing tunnel wall, prevent the effect that gas or air etc. permeate.
4. this concrete can be widely used in wall shutoff of the gas displacing coal-bed tunnel of gas and antiseepage in the colliery, and has the complex formation of characteristics such as soft, expansion, rheology or the surrounding rock supporting of other workings subject to dynamic pressure.
Description of drawings
Fig. 1 is the matchmaker's layer tunnel cross sectional representation that adopts the sprayed concrete mode;
Fig. 2 is the matchmaker's layer tunnel cross sectional representation that adopts the lining concrete mode;
Fig. 3 is the matchmaker's layer tunnel cross sectional representation that adopts concrete curtain-grouting mode.
Wherein:
The 1-coal seam;
The 2-tunnel;
3-excavates face;
The 4-sprayed concrete;
The 5-lining concrete;
6-concrete curtain-grouting.
Embodiment
One, these concrete starting material
1, coal dust
Coal dust can be gathered materials on the spot, and promptly directly utilizes coal mine down-hole drilling to be deposited in coal dust in the tunnel.It is made up of size difference, in irregular shape powder, and general diameter range is 10~1000 μ m, most 20~50 μ m, the about 450~500kg/m of tap density 3
2, cement
Cement adopts ordinary Portland cement (32.5,42.5, No. 52.5), and the listing product is arranged.
3, whipping agent
Whipping agent is this concrete main admixture, process, be out of shape, synthesize made by free of contamination animal protein oil and vegetables oil, neutral, with water good affinity is arranged, can in cement coal dust mixture slurry, produce separate and equally distributed bubble, form the foam capsule of the high stability of a large amount of sealings, show extremely strong steric strain and special tough stretching property.Require:
1. stable, promptly liquid film does not break in slurry, does not form communicating aperture;
2. even, promptly bubble diameter is close substantially, between 0.1~1mm;
3. low bleeding rate;
4. gelling material is not had negative interaction, promptly do not reduce the intensity of foamed concrete.
Whipping agent has the listing product.
4, medium coarse sand
Medium coarse sand is the auxiliary aggregate of this concrete curing intensity and cohesion, and specific surface area is less.When concrete strength was identical, the cement consumption that coarse sand needs was few; Cross thick sand and mix system, be easy to generate segregation and bleeding; For this reason, the fineness modulus of sand is moderate, and the sand of preparation flexible coal powder foam concrete should be used medium coarse sand, and grating should meet the requirements, fineness modulus 2.8, and density is 2.5~2.7g/cm.
Medium coarse sand has the listing product.
5, water-resisting agent
Water-resisting agent adopts waterproofing agent of organosilicon.Infiltrate the foamed concrete hole, avoid the flexible coal powder foam concrete suction and the unit weight increase, losing the lightweight characteristic also hardens; Greatly increase the barrier properties of flexible coal powder foam concrete simultaneously.
Water-resisting agent has the listing product.
7, water
Water is tap water.When preparing this concrete under the coal mine, allow to select for use clean natural water.
Two, site operation
1, needs to regulate concrete consolidation strength, gel time and early strength in the site operation, can add 2%~3% accelerating chemicals of cement weight.According to on-site concrete consumption (volume), in the concrete process for preparation, mix the fiber of volume content 0.2%-2.0%.
Fiber can be selected chopped carbon fiber or organic chemistry fiber for use.Fiber can improve its tension, anti-bending strength and toughness after joining matrix, and after taking place to ftracture, matrix also has bigger residual strength, have very low Young's modulus and good viscous deformation after making concrete setting, bonding firmly with the tunnel wall, guarantee enough mechanical strengths and with well-formed's cooperative transformation ability.Chopped carbon fiber is 2~5 millimeters scopes; The organic chemistry fiber has vinylon, nylon or polypropylene fibre to select for use, and length is 7~20 millimeters scopes.Fiber isotropic modulus is less than matrix elastic modulus, and the elongation during fracture is then than big 1~3 order of magnitude of breaking strain of matrix.
Fiber has the listing product.
2, according to different uniaxial compressive strengths and sample rate of permeation (concrete opposing water at the concrete pore to the chemosmotic ability in inside) requirement, by every cube of concrete, rig-site utilization proportioning working design:
3, the mode of shutoff heading wall
(1) sprayed concrete mode
As Fig. 1, the sprayed concrete mode is to adopt shotcrete machine tool (as the moving rotor-type shotcrete machine of full blast), sprays in the heading wall, forms the flexible barrier spray-up.
(2) lining concrete mode
As Fig. 2, the lining concrete mode is to adopt mould to build cast-in-place mode to form lining cutting.
(3) concrete curtain-grouting mode
As Fig. 3, concrete curtain-grouting mode is to adopt radially to bore 3-6m slotted hole (spacing 0.8-1.6m) along coal mine roadway, is pressed into concrete slurry with grouting pump, and the inner circle seepage proof curtain that forms is reinforced loose, soft rock mass simultaneously in the coal seam.
As the mode of above-mentioned shutoff heading wall and the anchor pole acting in conjunction that can stretch are formed high-ductility, high-intensity sheath, can solving in the soft-rock tunnel cavern excavation bolting and shotcreting common sprayed concrete spray-up and anchor pole flexibility, not match, can not satisfy soft rock initial deformation amount big and from body cracking avalanche problem; Can play sealing tunnel wall again, the effect that stops air admission coal seam or gas to overflow from the coal seam.The crack of shutoff heading wall, make it to form the air-locked protective layer of one deck on surface, coal seam and crack, top layer, prevent that the air in the tunnel from entering the coal seam under the suction function of pre-gas pumping, the big but low problem of gas density of flow improves and takes out effect in advance when alleviating pre-gas pumping.In addition, also avoid plugging material to cause the excessive dilution of coal product.
4, compliance test result
(1) adopts in the outstanding feasibility study of mixed gas displacing coal-bed gas control gas that carries out in musculus cutaneus band lane in eight ore deposits, colliery, tafelberg penta 2 12140 (penta 9-10 coal seam), test in place roadway surrounding rock coal seam is very broken, and air flows into the extraction hole by wall facial cleft crack.A large amount of inclusion of air have reduced gas density, have reduced gas flow, influence the displacement effect.The back adopts proportioning to be: cement (kg): coal dust (kg): medium coarse sand (kg): whipping agent (kg): water (kg): water-resisting agent (kg)=180: 800: 180: 20: 40: 15, and added 0.002m 3(ultimate compression strength is 11MPa to the flexible coal powder foam concrete of chopped carbon fiber, measured specific gravity 1290kg/m 3).Adopt the on-the-spot tunnel of construction of shotcrete mode shutoff extraction wall, the coal-seam gas recovery ratio of test in place is brought up to more than 30% by 20%.This project directly utilizes the coal dust in the tunnel to make aggregate, saves support cost more than 75%.
(2) to have local gas pressure big for coal field area, the Lushui River An Huanneng company Chang Cun colliery, the content height, and production intensity is big, and the gas concentrated characteristics of gushing out bring grave danger for the coal safe working.For reducing the outstanding risk of gas in the recovery process, tail lane, S3-9 exploiting field 13#~19# boring is adopted along layer hole air gas displacing coal-bed (G-ECBM).Coal seam, excavation back is pressed and is caused part roadway surrounding rock crack to produce, and produces a large amount of broken coals simultaneously.Tunnel wall to test holes place section adopts perfusion flexible coal powder foam concrete lining construction mode shutoff wall, proportioning is: cement (kg): coal dust (kg): medium coarse sand (kg): whipping agent (kg): water (kg): water-resisting agent (kg)=250: 750: 250: 30: 40: 15, and added 0.0025m 3Chopped carbon fiber.(ultimate compression strength is 12MPa, measured specific gravity 1366kg/m 3).The average methane flow of test holes on average exceeds 50% before testing, average methane concentration is greater than 20%.The coal dust that this project directly utilizes the boring in the tunnel to pile up is made aggregate, saves support cost more than 60%.

Claims (3)

1. flexible coal powder foam concrete is characterized in that main ingredient comprises:
By weight percentage
Cement 10~15;
Coal dust 35~65;
Medium coarse sand 20~45;
Water 3~4.5;
Water-resisting agent 0.1~0.3;
Whipping agent 1~1.5;
Mix 2~3% accelerating chemicals of cement weight;
Mix the chopped carbon fiber or the organic chemistry fiber of volume of concrete content 0.2~2.0%.
2. by the preparation method of the described a kind of flexible coal powder foam concrete of claim 1, it is characterized in that comprising the following steps:
1. with coal dust and medium coarse sand from on-site sampling, measure water ratio, content that should corresponding minimizing water;
2. cement, coal dust and medium coarse sand are poured into stirrer and mixed stirring 4~6 minutes;
3. get mixed solvent after water, water-resisting agent and whipping agent being mixed, and place the water tank that adds that stirs pusher side;
4. the limit adds the fiber limit and stirs in the mixture of 2. cement, coal dust and medium coarse sand, to full and uniform;
5. the mixed solvent that adds 3. water, water-resisting agent and whipping agent, restir promptly gets a kind of flexible coal powder foam concrete to full and uniform.
3. by the application of the described a kind of flexible coal powder foam concrete of claim 1, it is characterized in that:
The mode of shutoff heading wall or be the sprayed concrete mode, or be the lining concrete mode, or be concrete curtain-grouting mode;
(1) the sprayed concrete mode is to adopt the shotcrete machine tool to spray in the heading wall, forms the flexible barrier spray-up;
(2) the lining concrete mode is to adopt mould to build cast-in-place mode to form lining cutting;
(3) concrete curtain-grouting mode is to adopt slip casting to form seepage proof curtain, reinforces loose, soft rock mass.
CN2008102369392A 2008-12-19 2008-12-19 Flexible coal powder foam concrete and preparation thereof Expired - Fee Related CN101439950B (en)

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Application Number Priority Date Filing Date Title
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Application Number Priority Date Filing Date Title
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CN101439950B true CN101439950B (en) 2011-12-28

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Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2955790B1 (en) 2010-02-03 2012-03-23 Saint Gobain Weber METHOD FOR PROJECTING A FOAM MATERIAL AND COATING OBTAINED FROM SUCH A METHOD
CN102409997A (en) * 2011-12-09 2012-04-11 中国矿业大学 Curtain grouting anti-burst method for cutting through coal and gas bursting seam in shaft
CN103496901B (en) * 2013-09-23 2015-12-23 大同煤矿集团有限责任公司 Country rock wet shot concrete method inferior
CN103954501B (en) * 2014-04-23 2016-02-17 中国矿业大学(北京) Coal body flexibility reinforces test specimen determination method for parameter and application
CN105563654A (en) * 2015-12-25 2016-05-11 青岛中联混凝土工程有限公司 Foam concrete premixing production technique
CN110294635A (en) * 2019-07-05 2019-10-01 南通四建集团有限公司 A kind of the whitewashing slurry and its shotcrete construction method of concrete base layer

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1030904A (en) * 1987-07-25 1989-02-08 东北工学院 Flexible concrete spray coating support protection material
CN1281829A (en) * 2000-09-05 2001-01-31 开滦(集团)有限责任公司 Material for spraying lower tunnel of supporting well and its preparation method
CN1704385A (en) * 2004-05-25 2005-12-07 柳闻吉 Foam concrete and its production method and its foam reaction tank
CN101182175A (en) * 2007-11-22 2008-05-21 重庆大学 Coal gangue-fly ash foam concrete

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1030904A (en) * 1987-07-25 1989-02-08 东北工学院 Flexible concrete spray coating support protection material
CN1281829A (en) * 2000-09-05 2001-01-31 开滦(集团)有限责任公司 Material for spraying lower tunnel of supporting well and its preparation method
CN1704385A (en) * 2004-05-25 2005-12-07 柳闻吉 Foam concrete and its production method and its foam reaction tank
CN101182175A (en) * 2007-11-22 2008-05-21 重庆大学 Coal gangue-fly ash foam concrete

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