CN102505943A - Water conservation coal cutting method for small and medium-sized coal mines in waterhead area - Google Patents

Abstract

The invention discloses a water conservation coal cutting method for small and medium-sized coal mines in a waterhead area. The method comprises the following steps: 1, defining the position of a coal bed, that is, defining the thickness and the buried depth of the coal bed in an exploited coal mine according to a boring log; 2, defining exploitation parameters, that is, defining a roof rock beam bearing load, the higher limit value Lmax of the width of an exploitation strip, and the lower limit value Dmin of the width of a coal pillar; 3, defining an exploitation scheme, that is, defining the mining and the reservation widths during strip exploitation according to the Lmax and the Dmin, wherein the width L0 of a strip exploited during strip exploitation is smaller than or equal to Lmax, and the width D0 of a reserved coal pillar is larger than or equal to Dmin; and 4, exploiting, that is, exploiting the coal bed according to the conventional strip exploitation method, and reserving a coal pillar of which the width is D0 every time when a strip of which the width is L0 is exploited. The water conservation coal cutting method has the advantages that the design is reasonable; the implementation is convenient; the maneuverability is high; the using effect is good; and the problems of easily caused great loss of the phreatic water resource, and poor water conservation coal cutting effect during the conventional exploitation of the small and medium-sized coal mines in the waterhead area are solved.

Description

A kind of water head site medium and small colliery is used water-protection coal-mining method

Technical field

The invention belongs to the coal mining technical field, especially relate to a kind of water head site medium and small colliery and use water-protection coal-mining method.

Background technology

" water protection mining " problem in big coalfield, northern Shensi at the beginning of the exploitation of Shen Fu mining area, has just caused the concern of each side.The North Shaanxi gross area 8.06 * 104km ², account for 39.2% of Shaanxi Province's gross area.Wherein contain water surface area 9.5 * 104hm ², account for 24.5% of the whole province's water surface area.The gross amount of water resources of North Shaanxi is merely 10.9% of Shaanxi Province, and water resource is 849m per capita ³/ people is 72% of Shaanxi Province's water resource of per capita, 35% of national per capita share.This shows that the water resources quantity of North Shaanxi is comparatively poor.Thereby the importance of " water protection mining " problem in big coalfield, northern Shensi receives the attention of each side for many years.To coal seam, northern Shensi shallow in burial, there are the characteristics of desert type river and drought-enduring vegetation in the face of land, and water conservation mainly is to guarantee valuable and the diving resource favourable to the growth conditions of vegetation, stops further developing of face of land desertification.That a large amount of in the past mining Practice mainly concentrates on is large-scale, in the exploitation of super-huge mine; Because the work plane overlength, the overlength work plane has surpassed 400m at present, and advance distance reaches 3Km～5Km; And adopt whole caving methods to handle top board; The longwell retrusive advances, thereby causes the diving resource to run off in a large number, combines seam mining that overlying strata are destroyed in its water-retaining production and water preventing ability variation situation; Work plane stays establishes the certain altitude barrier pillar, and it is unsatisfactory to set up " water protection mining " effect in shallow draining seedbed at coal-smits burnt rock band.

Band exploitation is that the coal seam that will exploit is divided into more regular band and exploits; And adopt one during actual the exploitation; Stay one, and utilize the coal column that keeps to support overlying rock, thereby reduce the overlying strata depression; Moving and distortion of the control face of land, and reach the part exploitation method of ground protection purpose.Comprise hydraulic filling band, waste filling band, inbreak band, layering inbreak band, close-in seams crowd band, become to adopt and stay than band under band, irregular band and the old dead zone of ancient little kiln etc. from the arrangement form of band and exploitation method.Although band exploitation recovery ratio is low, resources loss is serious; But because village, China mining area is intensive, removal charge is huge, for the liberation village presses down coal; The band exploitation is as a kind of special coal-mining method that reduces ground settlement, and band exploitation having carried out coal mining underbuildings practice was all used in each mining area in recent years.

Summary of the invention

Technical problem to be solved by this invention is to above-mentioned deficiency of the prior art; Provide a kind of water head site medium and small colliery to use water-protection coal-mining method; It is reasonable in design, realization is convenient, workable and result of use good, what exist in the time of effectively solving existing water head site medium and small colliery exploitation is prone to cause multiple practical problems such as the diving resource runs off in a large number, the water protection mining effect is relatively poor.

For solving the problems of the technologies described above, the technical scheme that the present invention adopts is: a kind of water head site medium and small colliery is used water-protection coal-mining method, and the colliery of exploiting is the colliery that is positioned at water head site, and its water protection mining exploitation method may further comprise the steps:

Step 1, position, coal seam are confirmed: according to routine probing geological record method used in the process of coal mining; The exploitation colliery is drilled; And obtain after the log sheet in the colliery of exploiting; Based on said log sheet; Confirm the thickness and the buried depth in the existing coal seam in the colliery of exploiting, said seam roof is made up of a plurality of rock stratum and successively lay from the bottom to top a plurality of said rock stratum; Simultaneously, confirm the thickness of a plurality of rock stratum in the said top board respectively based on said log sheet;

Wherein, the quantity of a plurality of said rock stratum is n, and n said rock stratum is respectively first rock stratum, second rock stratum from the bottom to top ... n rock stratum, and the thickness of n said rock stratum is respectively h from the bottom to top ₁, h ₂... h _n

Step 2, operational parameter confirm that its deterministic process is following:

201, top board rock beam bearing load is confirmed, its deterministic process may further comprise the steps:

2011, the mechanical properties of rock of each rock stratum of top board test: according to the mechanical properties of rock method of testing of routine; Respectively the mechanical properties of rock parameter of a plurality of said rock stratum in the step 1 is tested; The mechanical properties of rock parameter of each rock stratum that test draws, said mechanical properties of rock parameter comprises unit weight, tensile strength and modulus of elasticity; Wherein, the unit weight of the n that draws said rock stratum of test is respectively γ from the bottom to top ₁, γ ₂γ _n, the modulus of elasticity of n said rock stratum is respectively E ₁, E ₂... E _n, the tensile strength of n said rock stratum;

2012, top board rock beam institute bearing load calculates:

Calculate i the rock stratum of laying from the bottom to top according to formula

and the formed load of combined influence is carried out in first rock stratum, i=1,2...n in the formula from first rock stratum;

And calculate i rock stratum combined influence carried out when forming load in first rock stratum, to said i+1 rock stratum of laying from the bottom to top from first rock stratum to the formed load (q in first rock stratum _I+1) ₁With i rock stratum to the formed load (q in first rock stratum _i) ₁Carry out difference relatively: when difference relatively draws (q _I+1) ₁＜(q _i) ₁The time, explain that absciss layer takes place in i the rock stratum of i+1 rock stratum and its underpart, i=m, and (q at this moment _m) ₁Be said seam roof rock beam institute bearing load, m is positive integer and m＜n;

202, the width higher limit of exploitation band confirms that its deterministic process may further comprise the steps:

2021, said top board rock beam is reduced to simply supported beam analysis: and said simply supported beam is the simply supported beam under the evenly distributed load effect; The normal stress at any point A place does on the said simply supported beam

M in the formula _xBe the moment of flexure of A place on cross section on the said simply supported beam, y is the distance of A place to said simply supported beam neutral axis, and t is the thickness of said simply supported beam and the thickness sum of m the rock stratum that t=lays from first rock stratum from the bottom to top;

2022, maximum positive pressure stress and maximum draw normal stress to convert: the maximal bending moment M of said simply supported beam _Max=qL ²/ 8, L is the lateral length of said simply supported beam in the formula; The positive pressure stress that bear in upside outward flange place, said simply supported beam middle part is maximum positive pressure stress; The normal stress that draws that bear in downside outward flange place, said simply supported beam middle part is that maximum is drawn normal stress; The downside outer edge at said simply supported beam middle part and upper edge place are equal to t/2 to the distance y of said simply supported beam neutral axis, and said maximum positive pressure stress draws the numerical value of normal stress to equate with maximum and the two is equal to

2023, the actual normal stress that bears of top board rock beam calculates: the actual normal stress that bears of said top board rock beam

F is safety factor and F=2～4 in the formula, R _lBe the tensile strength of said top board rock beam, said top board rock beam is made up of and j>=1 j rock stratum: when j=1, explain that said top board rock beam is a rock stratum and R _lTensile strength for this rock stratum; When j＞1, R _lTensile strength average for j rock stratum forming said top board rock beam;

2024, the width higher limit converts: with the σ that calculates in the step 2023 _eFormula in the substitution step 2022

Conversion draws the width higher limit of exploitation band

Q is the (q that calculates in the step 201 in the formula _m) ₁

203, the coal pillar width lower limit is confirmed, its deterministic process is following:

2031, coal column yield region width calculates:

According to formula Calculate coal column yield region width r _p, M is the average height in coal column height and the said coal seam of M=in the formula, and d is the exploitation disturbance factor and d=1.2～3.0, and β is the coefficient of horizontal pressure and β=0.25～0.40 at coal column yield region and the interval interface of elastic kernel place, and C is the cohesion of coal seam and top board contact surface, Be the angle of friction of coal seam and top board contact surface, σ _ZlBe coal column ultimate strength, P _xThe lateral restriction of the rib wherein unit of M is m, C, σ _ZlAnd P _xUnit be MPa; I is influence coefficient and i=3～1.5; Along with the continuous increase of M, i constantly reduces;

2032, the coal pillar width lower limit is confirmed: according to the coal column yield region width r that calculates in the step 2031 _p, confirm the width lower limit D of coal column _Min=2r _p+ r ₀, r wherein ₀Minimum value and r for coal column elastic kernel sector width ₀=0.1m～1m;

Step 3, recovery scheme are confirmed: according to the L that calculates in the step 2024 _MaxWith the D that calculates in the step 2032 _Min, confirm that adopting in the strip coating method recovery process stay yardstick, wherein the width L of the band of exploiting in the strip coating method recovery process ₀≤L _MaxAnd the width D of the coal column that stays ₀>=D _Min

Step 4, exploitation: according to conventional band exploitation method said coal seam is exploited, and in the actual recovery process, width of every exploitation is L ₀Band, staying and establishing a width is D ₀Coal column.

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method, it is characterized in that: after said coal seam is exploited according to conventional band exploitation method described in the step 4, forming a plurality of width is L ₀The band goaf, and to be installed with a width between adjacent two said band goafs be D ₀Strip coal pillar; And after according to conventional band exploitation method said coal seam being exploited, also need carry out closely knit filling with inserts respectively to a plurality of said bands goaf from front to back, and a plurality of fill areas of corresponding formation; A plurality of said bands goaf is carried out respectively in the closely knit filling process, from front to back adjacent two said strip coal pillars between the fill area are exploited.

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method; It is characterized in that: said coal seam is carried out in the recovery process described in the step 4 according to conventional band exploitation method; On said coal seam, arrange a plurality of coal mining sections or a plurality of coal-face, between adjacent two coal mining sections or adjacent two coal-faces through being installed with an isolated coal pillar; And after exploitation finished, all forming a plurality of width in each coal mining section or each coal-face was L ₀The district in the band goaf, being installed with a width between the band goaf in adjacent two said districts is D ₀The district in strip coal pillar;

Confirm adopting when staying yardstick in the strip coating method recovery process described in the step 3; Also need the width minimum value of said isolated coal pillar is confirmed; In the middle of said isolated coal pillar comprises water proof band and two be laid in respectively said in the middle of water proof band both sides the work plane yield region of exploitation and exploit the work plane yield region at present, and the width minimum value deterministic process of said isolated coal pillar is following:

Step I, middle water proof bandwidth L ₂₀Calculate: respectively according to side direction hydrostatic pressure coal pillar width design formulas

Or empirical formula

Water proof bandwidth L in the middle of calculating ₂₁With middle water proof bandwidth L ₂₂, K is safety factor and K=2～5 in the formula, and M is that average height and its unit in said coal seam is m, and P is that head pressure and its unit that middle water proof band that test draws is born is kgf/cm ², K _PFor tensile strength and its unit of coal body in the said coal seam is kgf/cm ², T _sThe water bursting coefficient that calculates for test;

Afterwards, the middle water proof bandwidth L to calculating ₂₁With middle water proof bandwidth L ₂₂Carry out difference relatively: work as L ₂₁>=L ₂₂The time, middle water proof bandwidth L ₂₀=L ₂₁Otherwise, middle water proof bandwidth L ₂₀=L ₂₂

Step II, isolated coal pillar width minimum value L _MinCalculate:

According to formula L _Min=L ₁+ L ₂₀+ L ₃, calculate the width minimum value of said isolated coal pillar, L in the formula ₁And L ₃Be respectively and exploit work plane yield region width and exploit work plane yield region width at present, and L ₁=L ₃The coal column yield region width r that calculates in=the step 2032 _p

According to conventional band exploitation method said coal seam is carried out in the recovery process width L that establishes isolated coal pillar that stays between adjacent two coal mining sections or adjacent two coal-faces in the step 4 _I0>=L _Min

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method, it is characterized in that: the m=1 described in the step 2012, and said seam roof rock beam is first rock stratum; T is the thickness of first rock stratum in the step 2021; L is the lateral length of first rock stratum in the step 2022; The rock beam of top board described in the step 2023 is first rock stratum and R _lTensile strength for first rock stratum.

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method; It is characterized in that: before said coal seam is exploited described in the step 4 according to conventional band exploitation method; Also need according to conventional coal column method for analyzing stability, determined recovery scheme in the employing step 3 is carried out the stability of institute's reserved coal pillar in the band recovery process and analyze.

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method, it is characterized in that: said conventional coal column method for analyzing stability is the equivalent material simulating experiment.

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method, it is characterized in that: M=3m～8m in the step 2031.

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method, it is characterized in that: in the step 2032 along with said seam roof stability weakens r gradually ₀Increase gradually.

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method, it is characterized in that: before operational parameter is confirmed in the step 2, also need the definite method by the conventional coal seam safety back production upper limit, to the safe back production upper limit M in said coal seam _xCalculate; And judge whether to adopt the band exploitation method that said coal seam is exploited according to result of calculation: when the average height M in said coal seam greater than the safe back production that calculates in limited time, then get into step 2 and said coal seam exploited by the band exploitation method; Otherwise, said coal seam is exploited by the broadwall method.

Above-mentioned a kind of water head site medium and small colliery is used water-protection coal-mining method, it is characterized in that: to the safe back production upper limit M in said coal seam _xWhen calculating, according to formula

5.1 is correction factor in the formula, n _xBe the layering number of plies in said coal seam, H ₀The average height of top, the said coal seam basement rock that draws for test.

The present invention compared with prior art has the following advantages:

1, method step is simple, realization is convenient and be easy to grasp.

2, reasonable in design, the present invention is rich in water layer and is not damaged in principle guaranteeing to cover on the coal seam, according to the Breadth Maximum of mechanics of materials simply supported beam Theoretical Calculation exploitation band; Guaranteeing to calculate the minimum dimension of strip coal pillar according to the limit equilibrium theory in the Elasticity on the bearing block long term stability principle basis; According to the yield region width of isolating coal column between the limit equilibrium theory meter panel in the Elasticity; According to the middle water proof bandwidth of side direction hydrostatic pressure design formulas and the interval isolated coal pillar of experience check formula calculating dial, finally confirm to isolate between the panel rational width of coal column; Through calculating maximum exploitation strip width and minimum pillar size; " country rock-coal column crowd " done the as a whole equivalent material simulating analysis of carrying out; Confirm the proportioning of each rock stratum in the simulated experiment, analyze the stability of " country rock-coal column crowd " system, the final reasonability of confirming the operational parameter of carrying.

3, result of use is good and practical value is high, and the final recovery scheme of confirming is reasonable, and " water protection mining " is effective, can not cause the diving resource to run off in a large number in the recovery process, and recovery ratio is higher.

In sum; The inventive method step is simple, reasonable in design, realization is convenient and workable, result of use is good; The water protection mining of definite recovery scheme effective, what exist in the time of effectively solving existing water head site medium and small colliery exploitation is prone to cause multiple practical problems such as the diving resource runs off in a large number, the water protection mining effect is relatively poor.

Through accompanying drawing and embodiment, technical scheme of the present invention is done further detailed description below.

Description of drawings

Method flow block diagram when Fig. 1 carries out water protection mining for the present invention.

Fig. 2 by in the present invention's first specific embodiment the bore hole columnar section of exploitation middle and small scale coal mine.

Fig. 3 analyzes the seat earth bearing pressure situation of change sketch map that draws for adopting the equivalent material simulating experiment in the present invention's first specific embodiment to selected band recovery scheme.

Fig. 4 is for carrying out the band exploitation view that water protection mining adopted in the present invention's first specific embodiment.

Fig. 5 by in the present invention's second specific embodiment the bore hole columnar section of exploitation middle and small scale coal mine.

Description of reference numerals:

The 1-strip coal pillar; Territory, 2-goaf; The 3-coal-face;

4-is unminded the zone.

The specific embodiment

A kind of water head site medium and small colliery as shown in Figure 1 is used water-protection coal-mining method, and the colliery of exploiting is the colliery that is positioned at water head site, and its water protection mining exploitation method may further comprise the steps:

Step 1, position, coal seam are confirmed: according to routine probing geological record method used in the process of coal mining; The exploitation colliery is drilled; And obtain after the log sheet in the colliery of exploiting; Based on said log sheet; Confirm the thickness and the buried depth in the existing coal seam in the colliery of exploiting, said seam roof is made up of a plurality of rock stratum and successively lay from the bottom to top a plurality of said rock stratum; Simultaneously, confirm the thickness of a plurality of rock stratum in the said top board respectively based on said log sheet.

Wherein, the quantity of a plurality of said rock stratum is n, and n said rock stratum is respectively first rock stratum, second rock stratum from the bottom to top ... n rock stratum, and the thickness of n said rock stratum is respectively h from the bottom to top ₁, h ₂... h _n

During actual the exploitation, the colliery of exploiting is the middle and small scale coal mine of 300,000 tons/year～900,000 tons/year of output.

Step 2, operational parameter confirm that its deterministic process is following:

201, top board rock beam bearing load is confirmed, its deterministic process may further comprise the steps:

2011, the mechanical properties of rock of each rock stratum of top board test: according to the mechanical properties of rock method of testing of routine; Respectively the mechanical properties of rock parameter of a plurality of said rock stratum in the step 1 is tested; The mechanical properties of rock parameter of each rock stratum that test draws, said mechanical properties of rock parameter comprises unit weight, tensile strength and modulus of elasticity; Wherein, the unit weight of the n that draws said rock stratum of test is respectively γ from the bottom to top ₁, γ ₂γ _n, the modulus of elasticity of n said rock stratum is respectively E ₁, E ₂... E _n, the tensile strength of n said rock stratum.

2012, top board rock beam institute bearing load calculates:

Calculate i the rock stratum of laying from the bottom to top according to formula

and the formed load of combined influence is carried out in first rock stratum, i=1,2...n in the formula from first rock stratum;

And calculate i rock stratum combined influence carried out when forming load in first rock stratum, to said i+1 rock stratum of laying from the bottom to top from first rock stratum to the formed load (q in first rock stratum _I+1) ₁With i rock stratum to the formed load (q in first rock stratum _i) ₁Carry out difference relatively: when difference relatively draws (q _I+1) ₁＜(q _i) ₁The time, explain that absciss layer takes place in i the rock stratum of i+1 rock stratum and its underpart, i=m, and (q at this moment _m) ₁Be said seam roof rock beam institute bearing load, m is positive integer and m＜n.

202, the width higher limit of exploitation band confirms that its deterministic process may further comprise the steps:

2021, said top board rock beam is reduced to simply supported beam analysis: and said simply supported beam is the simply supported beam under the evenly distributed load effect; The normal stress at any point A place does on the said simply supported beam

M in the formula _xBe the moment of flexure of A place on cross section on the said simply supported beam, y is the distance of A place to said simply supported beam neutral axis, and t is the thickness of said simply supported beam and the thickness sum of m the rock stratum that t=lays from first rock stratum from the bottom to top.

2022, maximum positive pressure stress and maximum draw normal stress to convert: the maximal bending moment M of said simply supported beam _Max=qL ²/ 8, L is the lateral length of said simply supported beam in the formula; The positive pressure stress that bear in upside outward flange place, said simply supported beam middle part is maximum positive pressure stress; The normal stress that draws that bear in downside outward flange place, said simply supported beam middle part is that maximum is drawn normal stress; The downside outer edge at said simply supported beam middle part and upper edge place are equal to t/2 to the distance y of said simply supported beam neutral axis, and said maximum positive pressure stress draws the numerical value of normal stress to equate with maximum and the two is equal to

2023, the actual normal stress that bears of top board rock beam calculates: the actual normal stress that bears of said top board rock beam F is safety factor and F=2～4 in the formula, R _lBe the tensile strength of said top board rock beam, said top board rock beam is made up of and j>=1 j rock stratum: when j=1, explain that said top board rock beam is a rock stratum and R _lTensile strength for this rock stratum; When j＞1, R _lTensile strength average for j rock stratum forming said top board rock beam.

2024, the width higher limit converts: with the σ that calculates in the step 2023 _eFormula in the substitution step 2022

Conversion draws the width higher limit of exploitation band

Q does in the formula

(the q that calculates in the step 201 _m) ₁

203, the coal pillar width lower limit is confirmed, its deterministic process is following:

2031, coal column yield region width calculates:

According to formula

Calculate coal column yield region width r _p, M is the average height in coal column height and the said coal seam of M=in the formula, and d is the exploitation disturbance factor and d=1.2～3.0, and β is the coefficient of horizontal pressure and β=0.25～0.40 at coal column yield region and the interval interface of elastic kernel place, and C is the cohesion of coal seam and top board contact surface,

Be the angle of friction of coal seam and top board contact surface, σ _ZlBe coal column ultimate strength, P _xThe lateral restriction of the rib wherein unit of M is m, C, σ _ZlAnd P _xUnit be MPa; I is influence coefficient and i=3～1.5; Along with the continuous increase of M, i constantly reduces.

2032, the coal pillar width lower limit is confirmed: according to the coal column yield region width r that calculates in the step 2031 _p, confirm the width lower limit D of coal column _Min=2r _p+ r ₀, r wherein ₀Minimum value and r for coal column elastic kernel sector width ₀=0.1m～1m.

Step 3, recovery scheme are confirmed: according to the L that calculates in the step 2024 _MaxWith the D that calculates in the step 2032 _Min, confirm that adopting in the strip coating method recovery process stay yardstick, wherein the width L of the band of exploiting in the strip coating method recovery process ₀≤L _MaxAnd the width D of the coal column that stays ₀>=D _Min

Step 4, exploitation: according to conventional band exploitation method said coal seam is exploited, and in the actual recovery process, width of every exploitation is L ₀Band, staying and establishing a width is D ₀Coal column.

In addition; Before said coal seam is exploited described in the step 4 according to conventional band exploitation method; Also need according to conventional coal column method for analyzing stability, determined recovery scheme in the employing step 3 is carried out the stability of institute's reserved coal pillar in the band recovery process and analyze.

Embodiment 1

As shown in Figure 2, in the present embodiment, the colliery of being exploited is for being positioned at the water head site elm Bu Jie colliery of (also claiming water source protection ground).Elm Bu Jie colliery is located in the Yu Bujie village of Yulin City north of the city 11km; Be positioned at the southwestern margin area, the refreshing mining area of elm of national planning; Administrative division is subordinate to Yuyang District Niu Jialiang town and has jurisdiction over; Designed productive capacity 0.06Mt/a when building at the beginning of 1993 (English Million ton/annual, promptly 1,000,000 tons/year), mine capacity promotes and is 0.30Mt/a after the technological transformation in 2008.Elm is foretold boundary's coal field and is located in loess plateau, northern Shensi the northern fringe and borders on the area with a hair Wu Su desert, and major part is typical aeolian dune and dust storm beach looks in the mining area in, and the desert coverage scale is more than 80%, is main with fixedly sand and semifixed sand, and the vegetation covering is better.Nos basement rock exposure in the scope of field with "nine squares", stratum, field with "nine squares" from the bottom to top for system group, Quaternary system mid Pleistocene series on the straight sieve group of system, the tertiary system in unite in unite on the Trias forever level ground group, the Jurassic system YAN ' AN FORMATION, the Jurassic system from the stone group, Quaternary system upper Pleistocene series Sa Lawu is plain organizes and Holocene series.2 ^-2Coal seam (i.e. the 2nd exploiting field in the 2nd layer of stratum) is a main minable coal seam unique in the field with "nine squares".2 ^-2The coal seam thickness in coal seam in 4.35m～5.57m scope, then 2 ^-2The coal seam average thickness in coal seam is 5.23m, and the buried depth in coal seam is 99m～168m.Wherein, 2 ^-2False roof is mud stone or the carbonaceous mud stone thin layer of thickness less than 0.5m in the roof; Directly the top is the siltstone of thickness 2.4m～6.67m, and individual lot pushes up direct tax basically and is stored on the coal seam, and basic top thickness degree is greater than 20m.2 ^-2Seat earth is mud stone, siltstone and the packsand that thickness does not wait, and is more stable.False roof be meant directly overlay on the industrial coal seam, mechanical strength is low and the part roof strata of difficult formation stress arch, after the coal extraction, very easily collapse.Directly caving zone is also claimed on the top, and this part rock stratum has collapsed the old man, is temporarily supported by support at stope, on direction of propulsion, can not remain the contact of transmitting horizontal force.

Elm Bu Jie colliery belongs to " water protection mining " zone, and extensive distribution Quaternary system unconsolidated sediment in the district wherein is mainly mid Pleistocene series from stone group yellowish-brown loess, is the good space of underground water storage and migration.Modern moving dunes on the loess formation provide good condition for oozing under the Atmospheric precipitation." the seven-star town sandstone " that underlies (the straight sieve group J 2Z sandstone of system in the Jurassic system), very military hole sandstone (2 ^-2Roof) be thick-huge thick-layer in thick-fine sandstone, it is more stable to distribute, continuity is good.Mostly two-layer sandstone is same water content except that there is the mud stone water proof part, rock crack is comparatively grown, and composing to deposit for underground water provides certain condition.The southern side, field with "nine squares" is because 2 ^-2Spontaneous combustion of coal seam makes roof caving, causes certain thickness caving zone and fissure zone, and its no water barrier in top exists, and links up with the loose rock class of Quaternary system aquifer, for underground water provides good condition.Field with "nine squares" water-bearing rock group is divided into two types, the one, loose rock class of Quaternary system and bedrock weathering zone hole, crack phreatic aquifer group, comprise alluvium, Holocene series river valley hole diving, upper Pleistocene series towards the lake layer hole diving and mid Pleistocene series loess crack hole diving; The 2nd, packsand hole, crack interlayer pressure-bearing water-bearing rock group in the Jurassic system.

In the present embodiment, when carrying out the water protection mining exploitation, its recovery process is following:

Step 1, position, coal seam are confirmed: according to routine probing geological record method used in the process of coal mining; The exploitation colliery is drilled; And the log sheet in the acquisition colliery of exploiting; See for details after Fig. 2; Based on said log sheet; Confirm the thickness and the buried depth in the existing coal seam in the colliery of exploiting, said seam roof is made up of a plurality of rock stratum and successively lay from the bottom to top a plurality of said rock stratum; Simultaneously, confirm the thickness of a plurality of rock stratum in the said top board respectively based on said log sheet.Wherein, the quantity of a plurality of said rock stratum is n, and n said rock stratum is respectively first rock stratum, second rock stratum from the bottom to top ... n rock stratum, and the thickness of n said rock stratum is respectively h from the bottom to top ₁, h ₂... h _n

In the present embodiment, said coal seam is 2 ^-2Coal seam and its average height are 5.2m, and the buried depth in said coal seam is 99m～168m.

In addition, be noted that: before operational parameter is confirmed in the step 2, also need definite method, the safe back production upper limit M in said coal seam by the conventional coal seam safety back production upper limit _xCalculate; And judge whether to adopt the band exploitation method that said coal seam is exploited according to result of calculation: when the average height M in said coal seam greater than the safe back production that calculates in limited time, then get into step 2 and said coal seam exploited by the band exploitation method; Otherwise, said coal seam is exploited by the broadwall method.

Safe back production upper limit M to said coal seam _xWhen calculating, according to formula

5.1 is correction factor in the formula, n _xBe the layering number of plies in said coal seam, H ₀The average height of top, the said coal seam basement rock that draws for test.

In the present embodiment, according to the mechanical properties of rock experimental test result of geotechnical boring, 2 ^-2The coal seam overlying rock belongs to middle gravity die, thereby gravity die overlying strata destruction mobile computing formula carries out the height of water flowing fractured zone expectation in selecting for use.Confirm the height of water flowing fractured zone design formulas according to " mine hydrogeology rules ":

N in the formula _x=1 (promptly calculating by the disposable overall height of adopting) calculates

${H_{\mathrm{li}}}^{\′}=\frac{100M_x}{3.3n_x+3.8}+5.1=\frac{100\×5.2}{3.3\×1+3.8}+5.1=78.3m.$

In order to guarantee the safe working of work plane, need stay to establish certain safe coal rock layer protective layer thickness.According to choose in " building, water body, railway and main roadway coal column stay establish and press the coal mining rules " subordinate list 6-4 regulation 6A (A=∑ M/n, ∑ M-accumulative total is adopted thick; The n-layering number of plies) as calculating protective layer thickness be: $H_b=6A=6\×\frac{5.2}{1}=31.2m.$

Because waterproof safety coal petrography post is made up of water flowing fractured zone and protective layer thickness jointly, its vertical height is:

H _sh＝H _li+H _b＝78.3+31.2＝109.5m。

According to " building, water body, railway and main roadway coal column and pressure coal mining rules " last three band law of development, if will guarantee that roof water does not penetrate in the work plane, need satisfy following relationship formula: H _Sh≤H ₀Then

Can draw and be limited to M in the safe working _x≤1.8m.

Therefore, when adopting " building, water body, railway and main roadway coal column with press the coal mining rules " to calculate in back production in limited time, elm foretells that the boundary is main adopts 2 ^-2The working thickness in coal seam must just can adopt the broadwall method less than 1.8m, and then realization " water protection mining ".Thereby, need to adopt and realize 2 with the band mining type ^-2The raising purpose of coal seam full-seam extraction and recovery ratio.

To sum up, the elm fore-telling coal master of circle adopts 2 ^-2Seam mining thickness just can adopt the broadwall method during less than 1.8m, and split band and do not develop into the water barrier loose aquifer under to guarantee to emit, thus realization " water protection mining " purpose, but cause at least 66% Coal Loss simultaneously.And the band exploitation can be used as a kind of raising recovery ratio, protects ecological water level, and leaves over effective mining type of coal column in the displacement of basement rock stable condition filling mining of following later stage.

Step 2, operational parameter confirm that its deterministic process is following:

201, top board rock beam bearing load is confirmed, its deterministic process may further comprise the steps:

2011, the mechanical properties of rock of each rock stratum of top board test: according to the mechanical properties of rock method of testing of routine; Respectively the mechanical properties of rock parameter of a plurality of said rock stratum in the step 1 is tested; The mechanical properties of rock parameter of each rock stratum that test draws, said mechanical properties of rock parameter comprises unit weight, tensile strength and modulus of elasticity; Wherein, the unit weight of the n that draws said rock stratum of test is respectively γ from the bottom to top ₁, γ ₂... γ _n, the modulus of elasticity of n said rock stratum is respectively E ₁, E ₂... E _n, the tensile strength of n said rock stratum.

In the present embodiment; (mechanical properties of rock that specifically is test 300 working face mining roof part rock stratum) tested with the mechanical properties of rock parameter of next rock stratum in 6 rock stratum and said coal seam more than the said coal seam; And obtain rock stratum physico-mechanical properties parameter list according to test result

See table 1 for details:

Table 1 rock stratum physico-mechanical properties parameter list

2012, top board rock beam institute bearing load calculates:

Calculate i the rock stratum of laying from the bottom to top according to formula and the formed load of combined influence is carried out in first rock stratum, i=1,2...n in the formula from first rock stratum;

And calculate i rock stratum combined influence carried out when forming load in first rock stratum, to said i+1 rock stratum of laying from the bottom to top from first rock stratum to the formed load (q in first rock stratum _I+1) ₁With i rock stratum to the formed load (q in first rock stratum _i) ₁Carry out difference relatively: when difference relatively draws (q _I+1) 1＜(q _i) ₁The time, explain that absciss layer takes place in i the rock stratum of i+1 rock stratum and its underpart, i=m, and (q at this moment _m) ₁Be said seam roof rock beam institute bearing load, m is positive integer and m＜n.

In the present embodiment, the load (q of the 1st rock stratum itself ₁) ₁=γ ₁h ₁=27.2 * 2.4=65.28KPa.

The formed load of combined influence is carried out to the 1st rock stratum in the 2nd rock stratum

${\left(q_2\right)}_1=\frac{E_1{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HDA0000110458070000032.png"\; state="\{\{state\}\}">h</figure-callout>}}_1({\mathrm{\&gamma;}}_1{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HDA0000110458070000032.png"\; state="\{\{state\}\}">h</figure-callout>}}_1+{\mathrm{\&gamma;}}_2{h}_2)}{E_1{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HDA0000110458070000032.png"\; state="\{\{state\}\}">h</figure-callout>}}_1^3+E_2{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA0000110458070000021.png,HDA0000110458070000031.png"\; state="\{\{state\}\}">h</figure-callout>}}_2^3}=\frac{6.5\&times;{2.4}^3\&times;(27.2\&times;2.4+26.38\&times;10.6)}{6.5\&times;{2.4}^3+9.0\&times;{10.6}^3}=\frac{89.856\&times;(65.28+279.628)}{6.5\&times;{2.4}^3+9.0\&times;{10.6}^3}$

$=2.867\mathrm{KPa}.$

Because (q ₂) ₁＜(q ₁) ₁, then this moment m=1, and this moment said seam roof rock beam be first rock stratum.That is to say that absciss layer takes place in the rock stratum of second rock stratum and its underpart in the said seam roof, then deadweight is only born in first rock stratum, and the load value on this moment top board rock beam is (q ₁) ₁=0.65kg/cm ²

In the actual recovery process, m also can be greater than 1, and absciss layer takes place for m rock stratum and its rock stratum, top of then laying from the bottom to top this moment, and said seam roof rock beam is formed in m the rock stratum of then laying from the bottom to top.

202, the width higher limit of exploitation band confirms that its deterministic process may further comprise the steps:

2021, said top board rock beam is reduced to simply supported beam analysis: and said simply supported beam is the simply supported beam under the evenly distributed load effect; The normal stress at any point A place is

on the said simply supported beam

M in the formula _xBe the moment of flexure of A place on cross section on the said simply supported beam, y is the distance of A place to said simply supported beam neutral axis, and t is the thickness of said simply supported beam and the thickness sum of m the rock stratum that t=lays from first rock stratum from the bottom to top.

In the present embodiment, t is the thickness of first rock stratum, and according to table 1, t=2.4m=240cm.

2022, maximum positive pressure stress and maximum draw normal stress to convert: the maximal bending moment M of said simply supported beam _Max=qL ²/ 8, L is the lateral length of said simply supported beam in the formula; The positive pressure stress that bear in upside outward flange place, said simply supported beam middle part is maximum positive pressure stress; The normal stress that draws that bear in downside outward flange place, said simply supported beam middle part is that maximum is drawn normal stress; The downside outer edge at said simply supported beam middle part and upper edge place are equal to t/2 to the distance y of said simply supported beam neutral axis, and said maximum positive pressure stress draws the numerical value of normal stress to equate with maximum and the two is equal to

In the present embodiment, L is the lateral length of first rock stratum.

2023, the actual normal stress that bears of top board rock beam calculates: the actual normal stress that bears of said top board rock beam

F is safety factor and F=2～4 in the formula, R _lBe the tensile strength of said top board rock beam, said top board rock beam is made up of and j>=1 j rock stratum: when j=1, explain that said top board rock beam is a rock stratum and R _lTensile strength for this rock stratum; When j＞1, R _lTensile strength average for j rock stratum forming said top board rock beam.

In the present embodiment, said top board rock beam is first rock stratum and R _lBe the tensile strength of first rock stratum, and according to table 1, R _l=3.4MPa=34.0kg/cm ²

In the present embodiment, F=2.5, the actual normal stress that bears of said top board rock beam

${\mathrm{\&sigma;}}_e=\frac{R_l}{F}=\frac{34.0}{2.5}=13.6\mathrm{kg}/{\mathrm{<figure-callout\; id="2"\; label="cm"\; filenames="HDA0000110458070000021.png,HDA0000110458070000031.png"\; state="\{\{state\}\}">cm</figure-callout>}}^2.$

2024, the width higher limit converts: with the σ that calculates in the step 2023 _eFormula in the substitution step 2022 Conversion draws the width higher limit of exploitation band

Q does in the formula

(the q that calculates in the step 201 _m) ₁=(q ₁) ₁=0.65kg/cm ²

During Practical Calculation, with the σ that calculates in the step 2023 _eσ in the replacement formula _Max, get the width higher limit that limit span is promptly exploited band $L_{\mathrm{Max}}=\sqrt{\frac{{4\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000110458070000021.png,HDA0000110458070000031.png"\; state="\{\{state\}\}">t</figure-callout>}}^2{\mathrm{\&sigma;}}_e}{3q}}=\sqrt{\frac{4\&times;{240}^2\&times;13.6}{3\&times;0.65}}=1270\mathrm{Cm}=12.7m.$

203, the coal pillar width lower limit is confirmed, its deterministic process is following:

2031, coal column yield region width calculates:

According to formula

Calculate coal column yield region width r _p, M is the average height in coal column height and the said coal seam of M=in the formula, and d is the exploitation disturbance factor and d=1.2～3.0, and β is the coefficient of horizontal pressure and β=0.25～0.40 at coal column yield region and the interval interface of elastic kernel place, and C is the cohesion of coal seam and top board contact surface,

Be the angle of friction of coal seam and top board contact surface, σ _ZlBe coal column ultimate strength, P _xThe lateral restriction of the rib wherein unit of M is m, C, σ _ZlAnd P _xUnit be MPa; I is influence coefficient and i=3～1.5; Along with the continuous increase of M, i constantly reduces.

During actual the exploitation, M=3m～8m in the step 2031; And along with the continuous increase of M, i constantly reduces.Formula

Analysis draws according to limit equilibrium theory, coal column ultimate strength σ in the formula _ZlAccording to formula σ _Zl=δ η σ _cCalculate, wherein η is the coal rheology coefficient, σ _cUniaxial compressive strength and its unit of the coal petrography test block that draws for test are MPa.

In the present embodiment, η=0.4 and σ _c=38.2MPa, coal column ultimate strength σ _Zl=δ η σ _c=2.729 (η σ _c) ^0.729=19.9MPa.Simultaneously; M=5.2m; D=1.8; β=0.252, C=3.0MPa,

Thereby,

2032, the coal pillar width lower limit is confirmed: according to the coal column yield region width r that calculates in the step 2031 _p, confirm the width lower limit D of coal column _Min=2r _p+ r ₀, r wherein ₀Minimum value and r for coal column elastic kernel sector width ₀=0.1m～1m.

Actual when the coal pillar width lower limit is confirmed, in the step 2032 along with said seam roof stability weakens r gradually ₀Increase gradually.

In the present embodiment, according to the width result of calculation of coal column yield region in the step 2031, the nuclear zone coal pillar width is greater than 2r _p=5.8m advises that on-the-spot coal column stays to establish width and be not less than 6.0m, this moment coal column elastic kernel sector width r ₀=0.2m.If the top board condition is relatively poor, advise effective coal column elastic kernel sector width r ₀=1.0m, i.e. coal column elastic kernel sector width r ₀Minimum value be 1.0m, this moment, institute reserved coal pillar width was not less than 6.8m.

That is to say, when the top board condition is better, D _Min=6.0m; And when the top board condition is relatively poor, D _Min=6.8m.

Step 3, recovery scheme are confirmed: according to the L that calculates in the step 2024 _MaxWith the D that calculates in the step 2032 _Min, confirm that adopting in the strip coating method recovery process stay yardstick, wherein the width L of the band of exploiting in the strip coating method recovery process ₀≤L _MaxAnd the width D of the coal column that stays ₀>=D _Min

Step 4, exploitation: according to conventional band exploitation method said coal seam is exploited, and in the actual recovery process, width of every exploitation is L ₀Band, staying and establishing a width is D ₀Coal column.

In the actual recovery process, after said coal seam is exploited according to conventional band exploitation method described in the step 4, forming a plurality of width is L ₀The band goaf, and to be installed with a width between adjacent two said band goafs be D ₀Strip coal pillar; And after according to conventional band exploitation method said coal seam being exploited, also need carry out closely knit filling with inserts respectively to a plurality of said bands goaf from front to back, and a plurality of fill areas of corresponding formation; A plurality of said bands goaf is carried out respectively in the closely knit filling process, from front to back adjacent two said strip coal pillars between the fill area are exploited.

In addition; Said coal seam is carried out in the recovery process described in the step 4 according to conventional band exploitation method; On said coal seam, arrange a plurality of coal mining sections or a plurality of coal-face 3, between adjacent two coal mining sections or adjacent two coal-faces 3 through being installed with an isolated coal pillar; And after exploitation finished, all forming a plurality of width in each coal mining section or each coal-face 3 was L ₀The district in the band goaf, being installed with a width between the band goaf in adjacent two said districts is D ₀The district in strip coal pillar.

Correspondingly; Confirm adopting when staying yardstick in the strip coating method recovery process described in the step 3; Also need the width minimum value of said isolated coal pillar is confirmed; In the middle of said isolated coal pillar comprises water proof band and two be laid in respectively said in the middle of water proof band both sides the work plane yield region of exploitation and exploit the work plane yield region at present, and the width minimum value deterministic process of said isolated coal pillar is following:

Step I, middle water proof bandwidth L ₂₀Calculate: respectively according to side direction hydrostatic pressure coal pillar width design formulas Or empirical formula Water proof bandwidth L in the middle of calculating ₂₁With middle water proof bandwidth L ₂₂, K is safety factor and K=2～5 in the formula, and M is that average height and its unit in said coal seam is m, and P is that head pressure and its unit that middle water proof band that test draws is born is kgf/cm ², K _PFor tensile strength and its unit of coal body in the said coal seam is kgf/cm ², T _sThe water bursting coefficient that calculates for test.

Afterwards, the middle water proof bandwidth L to calculating ₂₁With middle water proof bandwidth L ₂₂Carry out difference relatively: work as L ₂₁>=L ₂₂The time, middle water proof bandwidth L ₂₀=L ₂₁Otherwise, middle water proof bandwidth L ₂₀=L ₂₂

Step II, isolated coal pillar width minimum value L _MinCalculate:

According to formula L _Min=L ₁+ L ₂₀+ L ₃, calculate the width minimum value of said isolated coal pillar, L in the formula ₁And L ₃Be respectively and exploit work plane yield region width and exploit work plane yield region width at present, and L ₁=L ₃The coal column yield region width r that calculates in=the step 2032 _p

According to conventional band exploitation method said coal seam is carried out in the recovery process width L that establishes isolated coal pillar that stays between adjacent two coal mining sections or adjacent two coal-faces 3 in the step 4 _I0>=L _Min

When actual width to isolated coal pillar calculated, considered was adopted coal column is destroyed and influence, and coal column is near stope one side; Because the bearing pressure effect, sheet underworld gang in coal seam produces the crack, forms yield band; Become strong infiltration area; This part coal body has been lost the water proof ability basically, becomes the remaining deposit band of the coal column with extremely low water-resisting ability, and what really play impermeable role is that the mid portion of coal column is coal column elastic kernel district.Therefore, coal column is that isolated coal pillar is made up of three parts between work plane, has exploited work plane yield region width L ₁, exploit work plane yield region width L at present ₃With middle water proof bandwidth L ₂₀, promptly isolated coal pillar is by being made up of with middle elastic kernel district the yield region at coal column two ends.

In the present embodiment, according to the side direction hydrostatic pressure coal pillar width is calculated earlier, and adopt the formula of deriving by mechanics of materials simply supported beam principle

Calculate, consider that this mining area hydrogeological conditions is more clearly, and do not have what structure, safety K=2.5; Coal seam tensile strength K _p=13.2kg/cm ²Ponding absolute altitude in the goaf calculates according to 3 times of mining heights, the head pressure p=1.6kg/cm that the water proof band is born in the middle of drawing thus ², M=5.2m; The middle water proof bandwidth that then calculates according to the side direction hydrostatic pressure $L_{21}=0.5\mathrm{KM}\sqrt{\frac{3P}{K_p}}=0.5\&times;2.5\&times;5.2\&times;\sqrt{\frac{3\&times;1.6}{13.2}}=3.9m.$ And formula rule of thumb

When calculating, head pressure p=1.6kg/cm ², water bursting coefficient be said in the middle of in the ratio and present embodiment of the maximum hydrostatic pressure (or pressure) that bears of water proof band and its thickness, water bursting coefficient T _s=0.7, the middle water proof bandwidth that calculates of formula rule of thumb then $L_{22}=\frac{P}{T_s}+10=\frac{1.6}{0.7}+10=12.3m.$

To L ₂₁And L ₂₂Carry out difference relatively, and get maximum value, be i.e. L ₂₀=L ₂₂=12.3m.

Thereby, isolated coal pillar width minimum value L _Min=L ₁+ L ₂₀+ L ₃=2.9+12.3+2.9=18.1m; Thereby in the actual recovery process; As long as exploited work plane and exploit to stay between the work plane and establish the isolated coal pillar that width is not less than 18.1m at present, just can satisfy and isolate the anti-requirement of harnessing the river in goaf, the scene of suggestion stays the width of establishing isolated coal pillar to be not less than 20m.

To sum up, the Breadth Maximum of exploitation band is 12.7m; According to coal column load and Calculation on stability; Particularly consider " continuous beam " characteristic of band exploitation; The width of strip coal pillar must not be less than 6.0m, if the top board condition is relatively poor, the strip coal pillar width is not less than 6.8m; To guarantee that coal column has the elastic kernel district of certain width, realize the long-time stability of coal column; The width of isolating coal column between the panel should be less than 20.0m.

Confirm that thus the method that adopt in present stage elm Bu Jie colliery " water protection mining " is a longwell system band coal-mining method: promptly mining system adopts longwell to arrange; Adopt the band exploitation in the work plane system; Stay and establish strip coal pillar roof supporting and upper caldding layer, the protection aquifer.In conjunction with Fig. 4; Adopt " adopt 12 and stay 8 " scheme during the band exploitation; It is the band goaf (territory, goaf 2 that corresponding formation 12m is wide) of every exploitation 12m width; Stay the isolated coal pillar of establishing 8m (this coal column is a strip coal pillar 1, promptly is in the coal column in a coal mining section or the coal-face 3), Reference numeral 4 indications zone is for unminding regional 4.

In addition; Before said coal seam is exploited described in the step 4 according to conventional band exploitation method; Also need according to conventional coal column method for analyzing stability, determined recovery scheme in the employing step 3 is carried out the stability of institute's reserved coal pillar in the band recovery process and analyze.

In the present embodiment, said conventional coal column method for analyzing stability is the equivalent material simulating experiment.In the actual recovery process, also can adopt the RFPA2D program of the rock failure process numerical experimentation of Northeastern University that above-mentioned recovery scheme is carried out analytical calculation.

In the present embodiment; Adopt the equivalent material simulating experimental technique; When the stability of coal column in the band exploitation is carried out sunykatuib analysis, making a similar material model earlier, specifically is the plane stress shut die type of a length 3m, high 2m and wide 20cm; The model geometric similar proportion was got 1: 100, and this model can be simulated the limit of mining of buried depth 200m and length 300m.The geometric similarity constant alpha of the model that adopts _L=100, density affinity constant α _Y=1.57, stress similitude constant alpha=α _Lα _Y=100 * 1.57=157.When reality is made plane stress shut die type; Used cast material with quartz sand as aggregate; Gypsum, calcium carbonate are as cementitious materials and formulated by a certain percentage with water, and place Min layers is located in the model support, are sprinkled into mica powder simulation aspect between layer and the layer.It is as shown in table 2 that model is loaded size, order and material mixture ratio.Mud stone gets 828 in the proportioning, representes that promptly quartz sand accounts for 8/9; Gypsum, calcium carbonate account for 1/9 altogether, and wherein gypsum accounts for 2/10, and calcium carbonate accounts for 8/10.

Table 2 elm Bu Jie colliery plane stress shut die type material filling proportioning and lift height

In conjunction with Fig. 3; Through said plane stress shut die type " adopt 12 and stay 8 " band recovery process being carried out simulated test draws; The bullet nuclear district rate of institute's reserved coal pillar (specifically referring to coal column in the district) remains on more than 60%, and it is stable that overlying strata keep, and coal column middle part maximal support pressure 6.38MPa; Far below strength limit, thereby the recovery scheme that is adopted in the present embodiment can realize the purpose of " water-retaining production ".

Embodiment 2

As shown in Figure 5, in the present embodiment, the colliery of being exploited is two pier collieries, and it is positioned at 21km place, northeast, Yulin City city, Shaanxi Province, is under the jurisdiction of Yuyang District Chinese ephedra Liang Zhen administration, belongs to the place's local mine in the local mine mining area of planning.Two pier collieries are located in loess plateau, northern Shensi the northern fringe and border on the area with hair Wu Su desert.All covered by the Quaternary system unconsolidated formation in the scope of field with "nine squares", south is a loess distribution in blocks, is distributed with along both sides, Liu Xiang river towards, lake accumulated powder sand and inferior sandy soil.Landform loess exposed section is comparatively smooth in the district, and the south is high, and north, middle part are low, and height above sea level is between+1200～+ 1305.Covered no basement rock exposure by Quaternary system drift-sand and loess entirely in the scope of field with "nine squares".The stratum, field with "nine squares" is organized and Holocene series from stone group, Quaternary system upper Pleistocene series Sa Lawu element for the straight sieve group of system, Quaternary system mid Pleistocene series in unite in the Jurassic system YAN ' AN FORMATION, the Jurassic system from the bottom to top.Main coal-bearing strata is the YAN ' AN FORMATION of uniting in the Jurassic system, and wherein minable coal seam is 2 layers, and No. 3 coal seams are last layer minable coal seams in the district, and thickness is big and stable, and the whole district can adopt, and thickness is stabilized in 7.50m～8.73m, average 8.43m.To the east northeast progressive additive, Changing Pattern is obvious by Nan Xi in the coal seam, belongs to the thick-super high seam of stability.The coal seam is buried stable, buried depth 136.81m～196.58m.The bore hole columnar section in No. 3 coal seams, two pier collieries is seen Fig. 5.Have the canescence thick-layer shape of a layer thickness 30.00～38.68m thin in No. 3 roofs-middle grain length stone sand rock, promptly reference lamina " very military hole sandstone " is gone up in the zone; No. 3 seat earth is mud stone and powder packsand alternating layers, and coal seam and top, base plate present tangible contact relation.

Two pier collieries belong to " water protection mining " zone, and residing mining area is positioned at mao Wu Su desert and loess plateau, northern Shensi the northern fringe is bordered on the area, and landform is comparatively smooth in the scope of field with "nine squares", relative relief 105m.Belong to continental climate, average rainfall over the years is 410.01mm, and concentrates on for 7～September.The annual mean evaporation capacity is that 1907.2mm is 4.65 times of amount of precipitation.Thereby, belong to the very fragile zone of ecological environment, therefore, water table aquifer and underground reservoir under the protection desert, the ecology and the sustainable development in zone are extremely important hereto.

In the present embodiment, carry out water protection mining when exploitation, what its recovery process and embodiment 1 were different is:

Step 1 is carried out the position, coal seam when confirming, in conjunction with Fig. 5, the coal seam of being exploited is that No. 3 coal seams and its average height are 8.43m, and the buried depth in said coal seam is 136.81m～196.58m;

Carry out (the rock stratum that physical property is close, each rock stratum of top board in the step 2011; Be reduced to single rock stratum) mechanical properties of rock when test; No. 36 rock stratum more than the coal seam and No. 3 coal seams are tested with the mechanical properties of rock parameter of next rock stratum; And obtain rock stratum physico-mechanical properties parameter list according to test result, see table 3 for details:

Table 1 rock stratum physico-mechanical properties parameter list

Sequence number

The rock title

Bed thickness

Unit weight

Compressive strength

Tensile strength

Modulus of elasticity

		m	kg/m 3	MPa	MPa	MPa
								1	Arkose	0.8	2300	40.6	1.2	1.0
2	Siltstone	7.8	2400	63.2	1.4	0.3
							3	Mud stone	0.8	2360	65.4	1.8	0.6
4	Sandstone	4.3	2680	74.8	1.9	6.6
							5	Siltstone	6.5	2638	76.3	3.0	9.0
6	The particulate arkose	7.6	2720	81.39	2.4	6.5
							9	No. 3 coals	8.4	1420	29.2	1.3	0.4
10	Siltstone	18.6	2610	55.3	2.8	1.2

When carrying out the bearing load calculating of top board rock beam institute in the step 2012, the load (q of the 1st rock stratum itself ₁) ₁=γ ₁h ₁=27.2 * 7.6=206.72KPa; The formed load of combined influence is carried out to the 1st rock stratum in the 2nd rock stratum:

${\left(q_2\right)}_1=\frac{E_1{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HDA0000110458070000032.png"\; state="\{\{state\}\}">h</figure-callout>}}_1^3({\mathrm{\&gamma;}}_1{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HDA0000110458070000032.png"\; state="\{\{state\}\}">h</figure-callout>}}_1+{\mathrm{\&gamma;}}_2{h}_2)}{E_1{\mathrm{<figure-callout\; id="1"\; label="h"\; filenames="HDA0000110458070000032.png"\; state="\{\{state\}\}">h</figure-callout>}}_1^3+E_2{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="HDA0000110458070000021.png,HDA0000110458070000031.png"\; state="\{\{state\}\}">h</figure-callout>}}_2^3}=\frac{6.5\&times;{7.6}^3\&times;(27.2\&times;7.6+26.38\&times;6.5)}{6.5\&times;{7.6}^3+9.0\&times;{6.5}^3}=202.65\mathrm{kPa}<{\left(q_1\right)}_1;$

Because (q ₂) ₁＜(q ₁) ₁, then this moment m=1, and this moment No. 3 seam roof rock beams be first rock stratum.That is to say that absciss layer takes place in the rock stratum of second rock stratum and its underpart in No. 3 seam roofs, then deadweight is only born in first rock stratum, and the load value on this moment top board rock beam is got (q ₁) ₁=2.07kg/cm ²

In the step 2021 said top board rock beam is reduced to simply supported beam when analyzing, according to table 3, the thickness t of simply supported beam is the thickness of first rock stratum, and t=7.6m=760cm;

Carry out maximum positive pressure stress and maximum in the step 2022 when drawing normal stress to convert; The positive pressure stress that bear in upside outward flange place, said simply supported beam middle part is maximum positive pressure stress; The normal stress that draws that bear in downside outward flange place, said simply supported beam middle part is that maximum is drawn normal stress; The downside outer edge at said simply supported beam middle part and upper edge place are equal to t/2=380cm to the distance y of said simply supported beam neutral axis, and said maximum positive pressure stress draws the numerical value of normal stress to equate with maximum and the two is equal to the lateral length of L for first rock stratum;

When carrying out in the step 2023 that the top board rock beam is actual to be born normal stress and calculate, said top board rock beam is first rock stratum and R _lBe the tensile strength of first rock stratum, and according to table 3, R _l=2.4MPa=24.0kg/cm ², F=3, the actual normal stress that bears of said top board rock beam ${\mathrm{\&sigma;}}_e=\frac{R_l}{F}=\frac{24.0}{3.5}=6.9\mathrm{Kg}/{\mathrm{<figure-callout\; id="2"\; label="Cm"\; filenames="HDA0000110458070000021.png,HDA0000110458070000031.png"\; state="\{\{state\}\}">Cm</figure-callout>}}^2.$

When carrying out the conversion of width higher limit in the step 2024, with the σ that calculates in the step 2023 _eFormula in the substitution step 2022

Conversion draws the width higher limit of exploitation band

Q=(q in the formula ₁) ₁=2.07kg/cm ²During Practical Calculation, with the σ that calculates in the step 2023 _eσ in the replacement formula _Max, get the width higher limit that limit span is promptly exploited band $L_{\mathrm{Max}}=$ $\sqrt{\frac{4{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA0000110458070000021.png,HDA0000110458070000031.png"\; state="\{\{state\}\}">t</figure-callout>}}^2{\mathrm{\&sigma;}}_e}{3q}}=\sqrt{\frac{4\&times;{760}^2\&times;6.9}{3\&times;2.07}}=1600\mathrm{Cm}=16.0m;$ Then exploit the limit span L of band top board _MaxBe 16.0m, consider geology, mining influence factor, advise that on-the-spot band adopts the wide 12.0m of being no more than,

When carrying out the width calculating of coal column yield region in the step 2031, η=0.4 and σ _c=38.2MPa, coal column ultimate strength σ _Zl=δ η σ _c=2.729 (η σ _c) ^0.729=19.9MPa.Simultaneously; M=8.4m; D=2; β=0.252; C=3.0MPa,

calculate coal column yield region width

Carry out the coal pillar width lower limit in the step 2032 when confirming, according to the coal column yield region width r that calculates in the step 2031 _p, confirm the width lower limit D of coal column _Min=2r _p+ r ₀, r wherein ₀Minimum value and r for coal column elastic kernel sector width ₀=0.1m～1m, then coal pillar width is greater than 8.6m, advises that on-the-spot coal column stays to establish width and be not less than 9.0m; If the top board condition is relatively poor, coal column effective elasticity nuclear sector width is not less than 1.0m, advises that on-the-spot coal column stays to establish to be not less than 9.6m.

When recovery scheme is confirmed in the step 3, according to the L that calculates in the step 2024 _MaxWith the D that calculates in the step 2032 _Min, confirm that adopting in the strip coating method recovery process stay yardstick, calculate and finally confirm that two pier colliery band operational parameters be " adopt 12 and stay 10 ", promptly every band of exploiting the 12m width stays coal column in the 10m width district.

When exploiting in the step 4, said coal seam is exploited, and in the actual recovery process, the band that width of every exploitation is 12m stays and establishes a width coal column that is 10m according to conventional band exploitation method.

The above; It only is preferred embodiment of the present invention; Be not that the present invention is done any restriction, every technical spirit changes any simple modification, change and the equivalent structure that above embodiment did according to the present invention, all still belongs in the protection domain of technical scheme of the present invention.

Claims (10)

1. a water head site medium and small colliery is used water-protection coal-mining method, and the colliery of exploiting is the colliery that is positioned at water head site, and its water protection mining exploitation method may further comprise the steps:

Step 1, position, coal seam are confirmed: according to routine probing geological record method used in the process of coal mining; The exploitation colliery is drilled; And obtain after the log sheet in the colliery of exploiting; Based on said log sheet; Confirm the thickness and the buried depth in the existing coal seam in the colliery of exploiting, said seam roof is made up of a plurality of rock stratum and successively lay from the bottom to top a plurality of said rock stratum; Simultaneously, confirm the thickness of a plurality of rock stratum in the said top board respectively based on said log sheet;

Wherein, the quantity of a plurality of said rock stratum is n, and n said rock stratum is respectively first rock stratum, second rock stratum from the bottom to top ... n rock stratum, and the thickness of n said rock stratum is respectively h from the bottom to top ₁, h ₂... h _n

Step 2, operational parameter confirm that its deterministic process is following:

201, top board rock beam bearing load is confirmed, its deterministic process may further comprise the steps:

2011, the mechanical properties of rock of each rock stratum of top board test: according to the mechanical properties of rock method of testing of routine; Respectively the mechanical properties of rock parameter of a plurality of said rock stratum in the step 1 is tested; The mechanical properties of rock parameter of each rock stratum that test draws, said mechanical properties of rock parameter comprises unit weight, tensile strength and modulus of elasticity; Wherein, the unit weight of the n that draws said rock stratum of test is respectively γ from the bottom to top ₁, γ ₂γ _n, the modulus of elasticity of n said rock stratum is respectively E ₁, E ₂... E _n, the tensile strength of n said rock stratum;

2012, top board rock beam institute bearing load calculates:

Calculate i the rock stratum of laying from the bottom to top according to formula

and the formed load of combined influence is carried out in first rock stratum, i=1,2...n in the formula from first rock stratum;

And calculate i rock stratum combined influence carried out when forming load in first rock stratum, to said i+1 rock stratum of laying from the bottom to top from first rock stratum to the formed load (q in first rock stratum _I+1) ₁With i rock stratum to the formed load (q in first rock stratum _i) ₁Carry out difference relatively: when difference relatively draws (q _I+1) ₁＜(q _i) ₁The time, explain that absciss layer takes place in i the rock stratum of i+1 rock stratum and its underpart, i=m, and (q at this moment _m) ₁Be said seam roof rock beam institute bearing load, m is positive integer and m＜n;

202, the width higher limit of exploitation band confirms that its deterministic process may further comprise the steps:

2021, said top board rock beam is reduced to simply supported beam analysis: and said simply supported beam is the simply supported beam under the evenly distributed load effect; The normal stress at any point A place is

on the said simply supported beam

M in the formula _xBe the moment of flexure of A place on cross section on the said simply supported beam, y is the distance of A place to said simply supported beam neutral axis, and t is the thickness of said simply supported beam and the thickness sum of m the rock stratum that t=lays from first rock stratum from the bottom to top;

2022, maximum positive pressure stress and maximum draw normal stress to convert: the maximal bending moment M of said simply supported beam _Max=qL ²/ 8, L is the lateral length of said simply supported beam in the formula; The positive pressure stress that bear in upside outward flange place, said simply supported beam middle part is maximum positive pressure stress; The normal stress that draws that bear in downside outward flange place, said simply supported beam middle part is that maximum is drawn normal stress; The downside outer edge at said simply supported beam middle part and upper edge place are equal to t/2 to the distance y of said simply supported beam neutral axis, and said maximum positive pressure stress draws the numerical value of normal stress to equate with maximum and the two is equal to

2023, the actual normal stress that bears of top board rock beam calculates: the actual normal stress that bears of said top board rock beam F is safety factor and F=2～4 in the formula, R _lBe the tensile strength of said top board rock beam, said top board rock beam is made up of and j>=1 j rock stratum: when j=1, explain that said top board rock beam is a rock stratum and R _lTensile strength for this rock stratum; When j＞1, R _lTensile strength average for j rock stratum forming said top board rock beam;

2024, the width higher limit converts: with the σ that calculates in the step 2023 _eFormula in the substitution step 2022

Conversion draws the width higher limit of exploitation band

Q does in the formula

(the q that calculates in the step 201 _m) ₁

203, the coal pillar width lower limit is confirmed, its deterministic process is following:

2031, coal column yield region width calculates:

According to formula

Calculate coal column yield region width r _p, M is the average height in coal column height and the said coal seam of M=in the formula, and d is the exploitation disturbance factor and d=1.2～3.0, and β is the coefficient of horizontal pressure and β=0.25～0.40 at coal column yield region and the interval interface of elastic kernel place, and C is the cohesion of coal seam and top board contact surface, Be the angle of friction of coal seam and top board contact surface, σ _ZlBe coal column ultimate strength, P _xThe lateral restriction of the rib wherein unit of M is m, C, σ _ZlAnd P _xUnit be MPa; I is influence coefficient and i=3～1.5; Along with the continuous increase of M, i constantly reduces;

2032, the coal pillar width lower limit is confirmed: according to the coal column yield region width r that calculates in the step 2031 _p, confirm the width lower limit D of coal column _Min=2r _p+ r ₀, r wherein ₀Minimum value and r for coal column elastic kernel sector width ₀=0.1m～1m;

Step 3, recovery scheme are confirmed: according to the L that calculates in the step 2024 _MaxWith the D that calculates in the step 2032 _Min, confirm that adopting in the strip coating method recovery process stay yardstick, wherein the width L of the band of exploiting in the strip coating method recovery process ₀≤L _MaxAnd the width D of the coal column that stays ₀>=D _Min

Step 4, exploitation: according to conventional band exploitation method said coal seam is exploited, and in the actual recovery process, width of every exploitation is L ₀Band, staying and establishing a width is D ₀Coal column.

2. use water-protection coal-mining method according to the described a kind of water head site medium and small colliery of claim 1, it is characterized in that: after said coal seam is exploited according to conventional band exploitation method described in the step 4, forming a plurality of width is L ₀The band goaf, and to be installed with a width between adjacent two said band goafs be D ₀Strip coal pillar; And after according to conventional band exploitation method said coal seam being exploited, also need carry out closely knit filling with inserts respectively to a plurality of said bands goaf from front to back, and a plurality of fill areas of corresponding formation; A plurality of said bands goaf is carried out respectively in the closely knit filling process, from front to back adjacent two said strip coal pillars between the fill area are exploited.

3. use water-protection coal-mining method according to claim 1 or 2 described a kind of water head site medium and small collieries; It is characterized in that: said coal seam is carried out in the recovery process described in the step 4 according to conventional band exploitation method; On said coal seam, arrange a plurality of coal mining sections or a plurality of coal-face (3), between adjacent two coal mining sections or adjacent two coal-faces (3) through being installed with an isolated coal pillar; And after exploitation finished, all forming a plurality of width in each coal mining section or each coal-face (3) was L ₀The district in the band goaf, being installed with a width between the band goaf in adjacent two said districts is D ₀The district in strip coal pillar;

Confirm adopting when staying yardstick in the strip coating method recovery process described in the step 3; Also need the width minimum value of said isolated coal pillar is confirmed; In the middle of said isolated coal pillar comprises water proof band and two be laid in respectively said in the middle of water proof band both sides the work plane yield region of exploitation and exploit the work plane yield region at present, and the width minimum value deterministic process of said isolated coal pillar is following:

Step I, middle water proof bandwidth L ₂₀Calculate: respectively according to side direction hydrostatic pressure coal pillar width design formulas

Or empirical formula

Water proof bandwidth L in the middle of calculating ₂₁With middle water proof bandwidth L ₂₂, K is safety factor and K=2～5 in the formula, and M is that average height and its unit in said coal seam is m, and P is that head pressure and its unit that middle water proof band that test draws is born is kgf/cm ², K _PFor tensile strength and its unit of coal body in the said coal seam is kgf/cm ², T _sThe water bursting coefficient that calculates for test;

Afterwards, the middle water proof bandwidth L to calculating ₂₁With middle water proof bandwidth L ₂₂Carry out difference relatively: work as L ₂₁>=L ₂₂The time, middle water proof bandwidth L ₂₀=L ₂₁Otherwise, middle water proof bandwidth L ₂₀=L ₂₂

Step II, isolated coal pillar width minimum value L _MinCalculate:

According to formula L _Min=L ₁+ L ₂₀+ L ₃, calculate the width minimum value of said isolated coal pillar, L in the formula ₁And L ₃Be respectively and exploit work plane yield region width and exploit work plane yield region width at present, and L ₁=L ₃The coal column yield region width r that calculates in=the step 2032 _p

According to conventional band exploitation method said coal seam is carried out in the recovery process width L that establishes isolated coal pillar that stays between adjacent two coal mining sections or adjacent two coal-faces (3) in the step 4 _I0>=L _Min

4. use water-protection coal-mining method according to claim 1 or 2 described a kind of water head site medium and small collieries, it is characterized in that: the m=1 described in the step 2012, and said seam roof rock beam is first rock stratum; T is the thickness of first rock stratum in the step 2021; L is the lateral length of first rock stratum in the step 2022; The rock beam of top board described in the step 2023 is first rock stratum and R _lTensile strength for first rock stratum.

5. use water-protection coal-mining method according to claim 1 or 2 described a kind of water head site medium and small collieries; It is characterized in that: before said coal seam is exploited described in the step 4 according to conventional band exploitation method; Also need according to conventional coal column method for analyzing stability, determined recovery scheme in the employing step 3 is carried out the stability of institute's reserved coal pillar in the band recovery process and analyze.

6. use water-protection coal-mining method according to the described a kind of water head site medium and small colliery of claim 5, it is characterized in that: said conventional coal column method for analyzing stability is the equivalent material simulating experiment.

7. use water-protection coal-mining method according to claim 1 or 2 described a kind of water head site medium and small collieries, it is characterized in that: M=3m～8m in the step 2031.

8. use water-protection coal-mining method according to claim 1 or 2 described a kind of water head site medium and small collieries, it is characterized in that: in the step 2032 along with said seam roof stability weakens r gradually ₀Increase gradually.

9. use water-protection coal-mining method according to claim 1 or 2 described a kind of water head site medium and small collieries, it is characterized in that: before operational parameter is confirmed in the step 2, also need definite method, the safe back production upper limit M in said coal seam by the conventional coal seam safety back production upper limit _xCalculate; And judge whether to adopt the band exploitation method that said coal seam is exploited according to result of calculation: when the average height M in said coal seam greater than the safe back production that calculates in limited time, then get into step 2 and said coal seam exploited by the band exploitation method; Otherwise, said coal seam is exploited by the broadwall method.

10. use water-protection coal-mining method according to the described a kind of water head site medium and small colliery of claim 9, it is characterized in that: the safe back production upper limit M in said coal seam _xWhen calculating, according to formula

5.1 is correction factor in the formula, n _xBe the layering number of plies in said coal seam, H ₀The average height of top, the said coal seam basement rock that draws for test.

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