CN105021457A - Test and evaluation method for deep hard roof coal seam bump proneness - Google Patents

Abstract

The invention discloses a test and evaluation method for deep hard roof coal seam bump proneness. The method comprises the steps of: preparing standard pure coal test pieces, standard pure rock test pieces and standard coal-rock combination test pieces; calculating the residual energy release rate of the standard coal-rock combination test pieces; and evaluating the proneness of the standard coal-rock combination test pieces. The standard coal-rock combination test pieces of corresponding proportions are made according to the actual thickness of on-site hard roofs and coal bodies, and by means of a quantization process, the influence of the coal rock combination effect and the combination size effect to bump proneness is fully reflected, and the accuracy of the evaluation result is significantly enhanced. Also, the method provided by the invention takes the coal-rock combination residual energy release rate to evaluate the coal seam bump proneness, gives full consideration to the time effect of the residual energy and destruction process during coal-rock failure, overcomes the one-sidedness existing in simple use of energy index and failure time index, and solves the problem of erroneous judgment and misjudgment to bump proneness from the source.

Description

A kind of test and evaluation method for deep tight roof Burst Tendency of Coal Seam

Technical field

The present invention relates to a kind of test and evaluation method for deep tight roof Burst Tendency of Coal Seam.

Background technology

Rock burst is that the coal rock deformation energy instantaneous relase bringing out high strength is adopted in mine, in the corresponding phenomenon of adopting space and causing strong country rock to shake and extrude.China's coal-mine mining depth increases with the speed of annual about 10 meters, and the frequency that rock burst occurs and intensity increase gradually, has become one of major casualty of restriction China Mine Safety in Production.

Practice shows, rock burst is not all have generation at all mines, and its generation often needs coal petrography stone to meet certain physical property condition, namely has Burst Tendency.Coal petrography stone Burst Tendency is larger, and the danger that rock burst occurs is higher.Whether there is for weighing coal petrography the size of Burst Tendency and Burst Tendency, Chinese scholars proposes many indexes from aspects such as energy, time to rupture and rigidity respectively, as: play performance index, impact energy index, dynamic destruction time, uniaxial compressive strength, ratio of rigidity index etc., these indexs have promoted the development of impact orientation theory greatly, for certain basis has been established in the prediction of rock burst and control.

But, rock burst is that roof and floor, coal seam are under the initial stress and mine mining-induced stress acting in conjunction, power and the discontinuous transmission of energy and cause the discontinuous result of displacement deformation, there is the not simple Burst Tendency depending on coal seam in it, more closely related with the array configuration, architectural feature, Environmental effect, rock property etc. of coal rock layer.Therefore, the interaction of country rock and coal body, can one of the important factor in order that rock burst occurs, particularly deep tight roof condition, when evaluating Burst Tendency of Coal Seam, the interaction ignoring tight roof and coal body probably causes underestimating Burst Tendency of Coal Seam, hides some dangers for the safe working of mine.Theoretical research and field practice all show, for deep fractures, especially there is the condition of tight roof above coal seam, when its shock hazard being evaluated with the Burst Tendency index in coal seam merely, often there is " underestimating " phenomenon, be difficult to under this condition, the predication and prevention of rock burst provides accurate foundation.

Existing Burst Tendency evaluation method is many starts with from single indexs such as energy, time to rupture, intensity, fully can not reflect this essence, have sizable one-sidedness, easily causes misjudgement erroneous judgement.Such as, have the coal body of identical dynamic destruction time, when dump energy is different, its dynamic effect destroyed is different, and Burst Tendency is also different, only utilizes merely dynamic destruction time index to be difficult to provide accurate judgement to this kind of situation.

Summary of the invention

In view of above-mentioned the deficiencies in the prior art, a kind of test and evaluation method for deep tight roof Burst Tendency of Coal Seam provided by the invention, to quantize the Burst Tendency in tight roof coal seam, deep.

For solving the problems of the technologies described above, the present invention program comprises:

For a test and evaluation method for deep tight roof Burst Tendency of Coal Seam, it comprises the following steps:

The step of A, preparation standard pure coal test specimen, the pure rock test specimen of standard and standard coal petrography assembly test specimen;

The step of B, calculating standard coal petrography assembly test specimen dump energy rate of release;

C, the tendentious step of evaluation criteria coal petrography assembly test specimen.

Described test and evaluation method, wherein, concrete also the comprising of described steps A:

The determination of coal sample, rock sample height in A1, standard coal petrography assembly test specimen

According to the concrete geologic condition in coal seam to be determined, obtain thickness of coal seam H ₁and the thickness H of top tight roof ₂, the height h of the coal sample in coal petrography assembly test specimen of being settled the standard by following formula respectively ₁with the height h of rock sample ₂;

$h_1=\frac{0.1H_1}{H_1+H_2}$ Formula 1;

$h_2=\frac{0.1H_2}{H_1+H_2}$ Formula 2;

The processing of A2, coal sample and rock sample

Obtain coal body to be determined and tight roof sillar is transported to laboratory, adopt corning machine and cutting machine to produce diameter and be 50mm, highly be h ₁coal sample and diameter be 50mm, highly for h ₂rock sample, coal sample and rock sample prepare three respectively, and adopt corning machine and cutting machine to produce diameter and be 50mm, highly be standard pure coal test specimen and the pure rock test specimen of standard of 100mm, standard pure coal test specimen and the pure rock of standard prepare three respectively; All coal samples, rock sample, standard pure coal test specimen and standard pure rock test specimen two ends polish by Plane surface grinding machine, requires both ends of the surface nonparallelism≤0.01mm, diameter deviation≤0.02mm;

The making of A3, standard coal petrography assembly test specimen

Be h by the height processed ₁coal sample and be highly h ₂rock sample to stick together formation integral structure, coal sample, below rock sample, is made three diameters and is 50mm, is highly the standard coal petrography assembly test specimen of 100mm;

Pure for the standard processed coal test specimen, standard pure rock test specimen and standard coal petrography assembly test specimen are divided into three groups to be measured group, and often group comprises a standard pure coal test specimen, a pure rock test specimen of standard and a standard coal petrography assembly test specimen.

Described test and evaluation method, wherein, also comprises between described steps A and described step B: the compression test step of standard pure coal test specimen, the pure rock test specimen of standard and standard coal petrography assembly test specimen:

Adopt rigid pressure testing machine, uniaxial compression test, biaxial compression test or multiaxis compression test is carried out respectively to three groups to be measured group, obtain the trial curve of three groups to be measured group, often organize the stress-strain curve that trial curve comprises the stress time curve of a standard coal petrography assembly test specimen, the stress-strain curve of a standard pure coal test specimen and a pure rock test specimen of standard.

Described test and evaluation method, wherein, concrete also the comprising of described step B:

The peak strength of B1, standard coal petrography assembly test specimen is σ _ctime, the elastic strain energy Q that unit volume coal body gathers _sECfor:

$Q_{SEC}=\frac{{\mathrm{\σ}}_C^2}{2E_C}J/m^3$ Formula 3;

In formula 3: σ _c---the peak strength of standard coal petrography assembly test specimen, unit is Pa;

E _c---the elastic modulus of coal, unit is Pa;

B2, stress are σ _ctime, the elastic strain energy Q that unit volume rock mass gathers _sERfor:

$Q_{SER}=\frac{{\mathrm{\σ}}_C^2}{2E_R}J/m^3$ Formula 4;

In formula 4: E _r---the elastic modulus of rock, unit is Pa;

σ _c---the peak strength of standard coal petrography assembly test specimen, unit is Pa;

The required energy consumed of coal body that B3, destruction unit volume are in peak stress is A _x, its size is the area that behind standard pure coal test specimen peak, stress-strain diagram and strain axis surround;

B4, standard coal petrography assembly test specimen dump energy rate of release W _zTcalculating:

$W_{ZT}=\frac{{\mathrm{Ah}}_1{Q}_{SEC}+{\mathrm{Ah}}_2{Q}_{SER}-{\mathrm{Ah}}_1{A}_X}{D_T}$ Formula 5;

In formula 5: A---the cross-sectional area of coal petrography assembly test specimen, unit is m ²;

D _t---the dynamic destruction time of coal petrography assembly test specimen, unit is s.

Described test and evaluation method, wherein, concrete also the comprising of described step C:

Calculate the dump energy rate of release W of three groups to be measured group Plays coal petrography assembly test specimen _zT, the mean value getting three result of calculations is final W _zTvalue;

Employing standard coal petrography assembly test specimen dump energy rate of release W _zTwhen evaluating Burst Tendency of Coal Seam, its grade scale is: work as W _zTwhen≤0, soft coal layer; Work as 0<W _zTduring≤0.5J/s, weak Burst Tendency; Work as 0.5<W _zTduring≤2J/s, medium impact tendentiousness; Work as W _zTduring >2J/s, thump tendentiousness.

A kind of test and evaluation method for deep tight roof Burst Tendency of Coal Seam provided by the invention, the standard coal petrography assembly test specimen of corresponding proportion is made according to the actual (real) thickness of on-the-spot tight roof and coal body, according to its Burst Tendency of properties evaluations of standard coal petrography assembly test specimen, when overcoming simple its Burst Tendency of properties evaluations according to coal seam, country rock and the interactional deficiency of coal body can not be considered, process by quantifying, fully reflect the combined effect of coal petrography and the size effect of assembly to the tendentious impact of impact, the accuracy of evaluation result significantly improves, and the present invention evaluates Burst Tendency of Coal Seam with coal petrography assembly dump energy rate of release, the time effect of remaining energy and destructive process when having taken into full account that coal petrography destroys, overcome the simple one-sidedness adopting energy indexes and time to rupture index to exist, the problem to Burst Tendency misjudgement erroneous judgement is solved, the features such as the present invention has simply, evaluation result is accurate, easy to utilize from root.

Accompanying drawing explanation

Fig. 1 is the structural representation of Plays coal petrography assembly test specimen of the present invention;

Fig. 2 is the schematic diagram of the stress time curve of Fig. 1 Plays coal petrography assembly test specimen;

Fig. 3 is the structural representation of the pure coal test specimen of Plays of the present invention;

Fig. 4 is the schematic diagram of the stress-strain curve of the pure coal test specimen of Fig. 3 Plays;

Fig. 5 is the structural representation of the pure rock test specimen of Plays of the present invention;

Fig. 6 is the schematic diagram of the stress-strain curve of the pure rock test specimen of Fig. 5 Plays.

Embodiment

The invention provides a kind of test and evaluation method for deep tight roof Burst Tendency of Coal Seam, for making object of the present invention, technical scheme and effect clearly, clearly, the present invention is described in more detail below.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.

In order to more detailed explanation the present invention, below enumerate more detailed embodiment and be described.

3# coal seam, certain ore deposit buried depth 856-1137m, coal seam is grown stable, and structure is simple, thickness 5-9m, average thickness H ₁for 6.8m.Above coal seam, immediate roof is the siltstone of hard and compact, and uniaxial compressive strength is about 78.5MPa, average thickness H ₂for 13.2m.

Above-mentioned 3# coal seam belongs to tight roof condition coal seam, typical deep, and the step that its Burst Tendency was tested and evaluated to employing the inventive method is as follows:

In standard coal petrography assembly test specimen needed for shop experiment, the height h of coal ₁with the height h of rock ₂by thickness of coal seam H to be determined ₁and the thickness H of top tight roof ₂determine:

$h_1=\frac{0.1H_1}{H_1+H_2}=\frac{0.1\&times;6.8}{6.8+13.2}=0.034m;$

$h_2=\frac{0.1H_2}{H_1+H_2}=\frac{0.1\&times;13.2}{6.8+13.2}=0.066m;$

Obtain and judge that coal body and hard siltstone sillar are transported to laboratory, adopt corning machine and cutting machine to produce diameter respectively and be 50mm, highly be h ₁(0.034m) coal sample and diameter be 50mm, highly for h ₂(0.066m) each 3 of rock sample, and diameter is 50mm, is highly the standard pure coal test specimen of 100mm and each 3 of standard pure rock test specimen.Test specimen two ends polish by Plane surface grinding machine, requires both ends of the surface nonparallelism≤0.01mm, diameter deviation≤0.02mm.

AB seccotine is adopted to be h by the height processed ₁(0.034m) coal sample and be highly h ₂(0.066m) rock sample sticks together, and forms integral structure, and coal sample, below rock sample, is made 3 diameters and is 50mm, highly is the standard coal petrography assembly test specimen of 100mm.

Process 9 standard pure coal test specimens, standard pure rock test specimen and standard coal petrography assembly test specimen are divided into 3 groups to be measured group, often organize to be measured group and comprise 1 standard pure coal test specimen, 1 pure rock test specimen of standard and 1 standard coal petrography assembly test specimen.Adopting MTS815 electro-hydraulic servo pressure pilot system to carry out uniaxial compression test to often organizing standard specimen respectively, obtaining the trial curve of each group respectively, choose wherein one group to be measured group test, concrete as 2, shown in Fig. 4 and Fig. 6.

According to Fig. 2, the peak strength σ of standard coal petrography assembly test specimen _cfor 18.9MPa, dynamic destruction time D _tfor 329ms.

According to Fig. 4, the elastic modulus E of coal _cfor 3.5GPa, destroy the required energy A consumed of coal body that unit volume is in peak stress _xbe 3.58 × 104J/m ³.Standard pure coal test specimen stress is σ _ctime, the elastic strain energy Q that unit volume coal body gathers _sECfor:

$Q_{SEC}=\frac{{\mathrm{\&sigma;}}_C^2}{2E_C}=\frac{{(18.9\&times;{10}^6)}^2}{2\&times;3.5\&times;{10}^9}=5.1\&times;{10}^{4}J/m^3$

According to Fig. 6, the elastic modulus E of rock _rfor 21.8GPa, test specimen stress is σ _ctime, the elastic strain energy Q that unit volume rock mass gathers _sERfor:

$Q_{SER}=\frac{{\mathrm{\&sigma;}}_C^2}{2E_R}=\frac{{(18.9\&times;{10}^6)}^2}{2\&times;21.8\&times;{10}^9}=8.193\&times;{10}^{3}J/m^3$

The diameter of standard coal petrography assembly test specimen is 50mm, and its cross-sectional area A is 0.0019635m ², then coal petrography assembly dump energy rate of release W _zTfor:

$\begin{array}{c}{W}_{ZT}=\frac{{\mathrm{Ah}}_1{Q}_{SEC}+{\mathrm{Ah}}_2{Q}_{SER}-{\mathrm{Ah}}_1{A}_X}{D_T}\\ =\frac{0.0019635\&times;0.0034\&times;5.1\&times;{10}^4+0.0019635\&times;0.0066\&times;8.193\&times;{10}^3-0.0019635\&times;0.0034\&times;3.58\&times;{10}^4}{329\&times;{10}^{-3}}\\ =0.6311J/s\end{array}$

According to the trial curve of another two groups to be measured group, calculate standard coal petrography assembly test specimen dump energy rate of release W _zTbe respectively 0.6425J/s, 0.6508J/s, get the mean value calculated for three times and obtain, standard coal petrography assembly test specimen dump energy rate of release W _zTfinal calculated value be 0.6415.

Therefore, according to its grade scale, 3# coal seam, this ore deposit has medium impact tendentiousness.

Certainly; more than illustrate and be only preferred embodiment of the present invention; the present invention is not limited to enumerate above-described embodiment; should be noted that; any those of ordinary skill in the art are under the instruction of this instructions; made all equivalently to substitute, obvious form of distortion, within the essential scope all dropping on this instructions, protection of the present invention ought to be subject to.

Claims (5)

1., for a test and evaluation method for deep tight roof Burst Tendency of Coal Seam, it comprises the following steps:

The step of A, preparation standard pure coal test specimen, the pure rock test specimen of standard and standard coal petrography assembly test specimen;

The step of B, calculating standard coal petrography assembly test specimen dump energy rate of release;

C, the tendentious step of evaluation criteria coal petrography assembly test specimen.

2. test and evaluation method according to claim 1, is characterized in that, concrete also the comprising of described steps A:

The determination of coal sample, rock sample height in A1, standard coal petrography assembly test specimen

According to the concrete geologic condition in coal seam to be determined, obtain thickness of coal seam H ₁and the thickness H of top tight roof ₂, the height h of the coal sample in coal petrography assembly test specimen of being settled the standard by following formula respectively ₁with the height h of rock sample ₂;

$h_1=\frac{0.1H_1}{H_1+H_2}$ Formula 1;

$h_2=\frac{0.1H_2}{H_1+H_2}$ Formula 2;

The processing of A2, coal sample and rock sample

Obtain coal body to be determined and tight roof sillar is transported to laboratory, adopt corning machine and cutting machine to produce diameter and be 50mm, highly be h ₁coal sample and diameter be 50mm, highly for h ₂rock sample, coal sample and rock sample prepare three respectively, and adopt corning machine and cutting machine to produce diameter and be 50mm, highly be standard pure coal test specimen and the pure rock test specimen of standard of 100mm, standard pure coal test specimen and the pure rock of standard prepare three respectively; All coal samples, rock sample, standard pure coal test specimen and standard pure rock test specimen two ends polish by Plane surface grinding machine, requires both ends of the surface nonparallelism≤0.01mm, diameter deviation≤0.02mm;

The making of A3, standard coal petrography assembly test specimen

Be h by the height processed ₁coal sample and be highly h ₂rock sample to stick together formation integral structure, coal sample, below rock sample, is made three diameters and is 50mm, is highly the standard coal petrography assembly test specimen of 100mm;

Pure for the standard processed coal test specimen, standard pure rock test specimen and standard coal petrography assembly test specimen are divided into three groups to be measured group, and often group comprises a standard pure coal test specimen, a pure rock test specimen of standard and a standard coal petrography assembly test specimen.

3. test and evaluation method according to claim 2, is characterized in that, also comprises between described steps A and described step B: the compression test step of standard pure coal test specimen, the pure rock test specimen of standard and standard coal petrography assembly test specimen:

Adopt rigid pressure testing machine, uniaxial compression test, biaxial compression test or multiaxis compression test is carried out respectively to three groups to be measured group, obtain the trial curve of three groups to be measured group, often organize the stress-strain curve that trial curve comprises the stress time curve of a standard coal petrography assembly test specimen, the stress-strain curve of a standard pure coal test specimen and a pure rock test specimen of standard.

4. test and evaluation method according to claim 2, is characterized in that, concrete also the comprising of described step B:

B1, standard coal petrography assembly test specimen peak strength are σ _ctime, the elastic strain energy Q that unit volume coal body gathers _sECfor:

$Q_{SEC}=\frac{{\mathrm{\&sigma;}}_C^2}{2E_C}J/m^3$ Formula 3;

In formula 3: σ _c---the peak strength of standard coal petrography assembly test specimen, unit is Pa;

E _c---the elastic modulus of coal, unit is Pa;

B2, stress are σ _ctime, the elastic strain energy Q that unit volume rock mass gathers _sERfor:

$Q_{SER}=\frac{{\mathrm{\&sigma;}}_C^2}{2E_R}J/m^3$ Formula 4;

In formula 4: E _r---the elastic modulus of rock, unit is Pa;

σ _c---the peak strength of standard coal petrography assembly test specimen, unit is Pa;

The required energy consumed of coal body that B3, destruction unit volume are in peak stress is A _x, its size is the area that behind standard pure coal test specimen peak, stress-strain diagram and strain axis surround;

B4, standard coal petrography assembly test specimen dump energy rate of release W _zTcalculating:

$W_{ZT}=\frac{{\mathrm{Ah}}_1{Q}_{SEC}+{\mathrm{Ah}}_2{Q}_{SER}-{\mathrm{Ah}}_1{A}_X}{D_T}$ Formula 5;

In formula 5: A---the cross-sectional area of coal petrography assembly test specimen, unit is m ²;

D _t---the dynamic destruction time of coal petrography assembly test specimen, unit is s.

5. test and evaluation method according to claim 4, is characterized in that, concrete also the comprising of described step C:

Calculate the dump energy rate of release W of three groups to be measured group Plays coal petrography assembly test specimen _zT, the mean value getting three result of calculations is final W _zTvalue;

Employing standard coal petrography assembly test specimen dump energy rate of release W _zTwhen evaluating Burst Tendency of Coal Seam, its grade scale is: work as W _zTwhen≤0, soft coal layer; Work as 0<W _zTduring≤0.5J/s, weak Burst Tendency; Work as 0.5<W _zTduring≤2J/s, medium impact tendentiousness; Work as W _zTduring >2J/s, thump tendentiousness.