CN103940723B - The method of Fast Measurement underground coal mine workplace front, laboratory coal body permeability - Google Patents
The method of Fast Measurement underground coal mine workplace front, laboratory coal body permeability Download PDFInfo
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Abstract
The invention discloses a kind of method measuring underground coal mine workplace front coal body permeability, belong to channel of coal mining working surface diaster prevention and control field.It is first by measuring colliery mine monitoring stress system at the scene, obtain the mining-induced stress distribution curve of workplace front coal body, and in conjunction with face propulsion speed, draw out the change curve of a distance, workplace front coal body unit suffered mining-induced stress in advance of the face process; Then Visual is utilized? the establishment axial compression loading of C++ programming language and confined pressure unloading synchronous servo control program, import true triaxial permeability test macro Computer Control Unit, and then by the simulation of true triaxial permeability test with the advance of the face, the mining-induced stress change procedure of the coal body unit of workplace front certain distance, finally obtains the permeability value with coal body unit during the advance of the face and Changing Pattern thereof.The inventive method can measure the permeability of driving face and coal face front coal body accurately and rapidly.
Description
Technical field
The invention belongs to channel of coal mining working surface diaster prevention and control field, be specifically related to the method for Fast Measurement underground coal mine workplace front, a kind of laboratory coal body permeability.
Background technology
Gas Disaster is the very big factor that restriction China's coal-mine industrial security is produced, the problems such as the blast that mine gas causes, fire and coal and gas prominent, to be present in coal production industry and comparatively serious always.Gas drainage is the effective means of administering mine gas disaster, by arranging that in coal seam extraction is holed, negative pressure is produced at bore inner by drainage pump, coal body is detached by composing the gas deposited in coal seam, thus the gas bearing capacity in reduction coal seam, reduce coal-bed gas pressure, the potential threat of mine gas to Safety of Coal Mine Production can be eliminated to a certain extent.
The arrangement of extraction boring is a ring important in gas suction by drilling technique.The spacing of wells is excessive, and gas drainage can be caused insufficient, and spacing is too small, can cause the waste of high cost and device resource, and whether drilling depth is in coalmass crevasse, pores'growth preferably scope, the gas drainage effect that can affect equally.Therefore, the Reasonable Arrangement of the spacing of wells, drilling depth is the key that high-level efficiency draws out methane; The permeability value of coal body can be used as the reference of above-mentioned extraction technological parameter.The permeability feature of comprehensive analysis workplace front different depth stage coal body, can be driving face firedamp taking-out discharging drilling depth of placement, coal face firedamp taking-out discharging drilling arrangement pitch provides reliable basis.And on-site measurement coal body permeability under conventional situation, technique is loaded down with trivial details, operating environment is poor, and measurement result exists relatively large deviation with actual osmotic value.
Therefore, be badly in need of the method for a kind of Fast Measurement workplace front coal body permeability in coal production work, can conveniently measure coal body permeability, for the setting parameter of gas suction by drilling work provides reliable basis.
Summary of the invention
The invention discloses the method for Fast Measurement underground coal mine workplace front, a kind of laboratory coal body permeability, the method is by measuring the mining-induced stress distribution of workplace front coal body, be plotted in and adopt action lower workplace front coal body unit with the stress changing curve in advance of the face process, and then the synchronous servo control program of establishment axial compression loading and confined pressure unloading, utilize true triaxial permeability test macro, accurate simulation mining-induced stress mechanism, realizes the Fast Measurement to workplace front coal body permeability.
Technical solution of the present invention comprises:
Measure a method for underground coal mine workplace front coal body permeability, comprise the following steps:
Step 1, mensuration workplace front coal body mining-induced stress, it comprises step by step following:
A utilizes computing machine that mining influence plane domain is divided into grid, and using each grid node as measuring point, move towards to arrange several boring along workplace at measuring point place, each adjacent boring is q along workplace strike separation, drilling depth be followed successively by L, L+1p, L+2p, L+3p ... L+np, wherein, L+np<100m, n are nonnegative number;
B preparing experiment hardware, described Experimental Hardware comprises mine monitoring stress system, and described mine monitoring stress system comprises system host, borehole stressmeter, guide pole, regulator and stabilized voltage supply;
C installs Experimental Hardware, meets step a, with guide pole, borehole stressmeter is slowly sent into boring assigned address, then injects oil pressure, and stress induction probe is initiatively coupled with coal and rock; Underground part utilizes mining communication cable to connect stabilized voltage supply, regulator, builds pressure monitoring substation; Above ground portion connected system main frame;
D starts stabilized voltage supply, and stress in coal bed is converted into the oil pressure of hydraulic oil by described borehole stressmeter, and oil pressure is converted into electric signal again, finally transfers pressure transmission to system host, and described system host is for collecting Monitoring Data and classifying to it, process;
Step 2, drafting coal body element stress change curve,
The data monitored in above-mentioned steps d are added up, makes form, describe workplace front coal body mining-induced stress σ
1, σ
2, σ
3distribution on coal body depth direction X, binding isotherm draws mining-induced stress σ on three directions that workplace front coal body internal element carries then
1, σ
2, σ
3not stress value in the same time in advance of the face process, carries out record, according to list data with form, with time t for transverse axis, with mining-induced stress value for the longitudinal axis, carry out curve fitting by MATLAB software, the change curve of square coal body unit mining-induced stress t in time in face of drawing;
Step 3, establishment axial compression loading, confined pressure unloading synchronous servo control program,
With the coal body element stress change curve drawn in step 2 for foundation, utilize visual c++ programming language to write axial compression loading and confined pressure unloading synchronous servo control program, import true triaxial permeability test macro Computer Control Unit;
Step 4, true triaxial permeability test macro measure coal body permeability, and it comprises step by step following:
E makes coal body test specimen, samples of coal pulled, and being processed into is highly l, and cross-sectional area is the rectangular parallelepiped test specimen of A, is placed in vacuum drying chamber, heating, drying, obtains coal body test specimen;
F installs, and utilizes boring and coring sampling method to arrange boring at workplace, above-mentioned coal body test specimen is loaded true triaxial permeability test bed;
G starts, and start-up simulation machine control device, described coal body test specimen three-dimensional stress initial value sets according to the accurate hydrostatic force state in coal seam, i.e. σ
1=σ
2=σ
3=γ h, applies methane gas pressure, inlet end gas pressure P
1for coal-bed gas pressure, outlet side gas pressure P
2for air pressure near workplace;
H runs, and runs axial compression loading and confined pressure unloading synchronous servo control program, completes the simulation of mining-induced stress mechanism, after gas exit velocity is stable, measure gas porous flow amount Q in time t
0, binding isotherm calculates coal body test specimen permeability K, obtains the permeability that the workplace front degree of depth is L place coal body unit.
As a preferred version of the present invention, in above-mentioned steps h, calculate permeability according to following formula (1):
In formula: K---permeability, md;
P
0---atmospheric pressure, MPa;
Q
0---gas porous flow amount, cm
3/ s;
μ---gas viscosity coefficient, gets 0.0158cPa;
L---coal body height of specimen, cm;
P
1---inlet end gas pressure, MPa;
P
2---outlet side gas pressure, MPa;
A---test specimen cross-sectional area, cm
2.
The Advantageous Effects that the present invention brings:
The invention discloses the method for Fast Measurement underground coal mine workplace front, a kind of laboratory coal body permeability, the method can measure the permeability of driving face and coal face front coal body accurately and rapidly; The permeability feature of comprehensive analysis workplace front different depth stage coal body, can be driving face firedamp taking-out discharging drilling depth of placement, coal face firedamp taking-out discharging drilling arrangement pitch provides reliable basis, contribute to promoting coal bed gas drainage effect, control coal-mine gas disaster, thus promote the safety of coal production work and stablize; Compare traditional coal body permeability determination technology, this technology eliminates loaded down with trivial details site technique, convenient, quick, decreases the time of mensuration work cost.
In addition, coal body test specimen stress path can accurately be determined based on field measurement, and then room true triaxial permeability test by experiment, more system and accurate coal body permeability data can be obtained.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, explanation clear, complete is further done to the present invention:
Fig. 1 is mine monitoring stress system schematic diagram of the present invention;
Fig. 2 is true triaxial permeability test macro schematic diagram of the present invention;
Fig. 3 is coal body unit mining-induced stress of the present invention curve map over time;
In figure, 1, system host, 2, borehole stressmeter, 3, guide pole, 4, regulator, 5, stabilized voltage supply, 6, pressure monitoring substation, 7, working face wall, 8, gas storage tank, 9, inlet end tensimeter, 10, axial compression charger, 11, confined pressure charger, 12, outlet side tensimeter, 13, flowmeter, 14, gas piping, 15, coal body test specimen, 16, Computer Control Unit.
Embodiment
The invention provides the method for Fast Measurement underground coal mine workplace front, a kind of laboratory coal body permeability, for making object of the present invention, technical scheme and advantage clearly, clearly, below by with the example of certain workplace front, ore deposit 1314 coal body permeability determination, the present invention is described in more detail.
First to Experimental Hardware selected by the present invention: mine monitoring stress system and true triaxial permeability test macro, following explanation is done:
Shown in composition graphs 1, mine monitoring stress system, comprise system host 1, borehole stressmeter 2, guide pole 3, regulator 4 and stabilized voltage supply 5, wherein, system host 1 major function collects Monitoring Data, on the other hand data classified, process, and show data sheet with man-machine dialog interface; Guide pole 3 is for sending borehole stressmeter 2 into default bore position, and borehole stressmeter 2 is connected by the input port of circuit with regulator 4, and the output port of regulator 4 is connected with system host, and stabilized voltage supply 5 is connected for it provides electricity with regulator 4;
Shown in composition graphs 2, true triaxial permeability test macro, comprise gas storage tank 8, inlet end tensimeter 9, axial compression charger 10, confined pressure charger 11, outlet side tensimeter 12, flowmeter 13, gas piping 14, coal body test specimen 15 and Computer Control Unit 16, gas piping 14 connects gas storage tank 8, inlet end tensimeter 9, piercing test platform is inner, and at outlet side connection traffic meter 13, outlet side tensimeter 12, the control to whole system is realized by Computer Control Unit, comprise and control axial compression charger 10, confined pressure charger 11, and regulate the gas pressure of inlet end and outlet side, force value is shown by inlet end tensimeter 9 and outlet side tensimeter 12.
The present invention, a kind of method measuring underground coal mine workplace front coal body permeability, comprises the following steps:
Step 1, measures coal body mining-induced stress
First, utilize computing machine that mining influence plane domain is divided into grid, and using each grid node as point position, according to this scheme, move towards to arrange several boring along workplace, adjacent boring is 10m along workplace strike separation, plan measures 20m place, workplace front coal body permeability, and learn according to field measurement, the coal body within the 50m of workplace front is subject to mining influence, then drilling depth is followed successively by 20m, 22m, 24m, 26m,, 50m;
Secondly, be the boring of 80mm at each measuring point place successively placement diameter, with guide pole 3, borehole stressmeter 2 is slowly sent into boring assigned address, then oil pressure is injected, stress induction probe is initiatively coupled with coal and rock, and underground part utilizes mining communication cable to connect stabilized voltage supply 5, regulator 4, builds pressure monitoring substation 6, above ground portion connected system main frame 1, lightning arrester, complete the building work of colliery mine monitoring stress system;
Finally, start stabilized voltage supply 5 switch, borehole stressmeter 2 is converted into the oil pressure of hydraulic oil stress in coal bed, and oil pressure is converted into electric signal again, is finally scaled pressure transmission to ground system main frame 1; System host 1 controls whole colliery mine monitoring stress system, communication is carried out on the one hand with down-hole pressure Monitor Sub-Station of Less 6, collect Monitoring Data, on the other hand data classified, process, and show data sheet with man-machine dialog interface, obtain under mining influence with this, the horizontal direction mining-induced stress σ of different depth place, workplace front coal body unit
1, σ
2and vertical direction mining-induced stress σ
3;
Step 2, draws coal body element stress change curve
Statistics colliery mine monitoring stress system measures the data obtained, describes the distribution of coal body inner three-dimensional stress in workplace front on coal body depth direction X, charges to table 1 ~ table 3.
Table 1 horizontal stress σ
1at the distribution table of coal body depth direction
| X | 20m | 22m | 24m | … | 50m |
| σ 1 | 11.3MPa | 14.5MPa | 18.7MPa | … | 30.0MPa |
Table 2 horizontal stress σ
2at the distribution table of coal body depth direction
| X | 20m | 22m | 24m | … | 50m |
| σ 2 | 13.2MPa | 13.0MPa | 17.2MPa | … | 28.5MPa |
Table 3 perpendicular stress σ
3at the distribution table of coal body depth direction
| X | 20m | 22m | 24m | … | 50m |
| σ 3 | 44.3MPa | 45.0MPa | 38.2MPa | … | 14.7MPa |
Known work face advance distance every day 3m, namely fltting speed is 0.125m/h, the distribution of mining-induced stress then described by table 1 ~ table 3 on coal body depth direction X, in conjunction with face propulsion speed, draw the change procedure of mining-induced stress that workplace front coal body internal element carries in advance of the face process t in time, charge to table 4 ~ table 6:
Table 4 coal body unit horizontal stress σ
1change list in time
| t | 0 | 16h | 32h | … | 240h |
| σ 1 | 30.0MPa | 18.7MPa | 14.5MPa | … | 11.3MPa |
Table 5 coal body unit horizontal stress σ
2change list in time
| t | 0 | 16h | 32h | … | 240h |
| σ 2 | 28.5MPa | 17.2MPa | 13.0MPa | … | 13.2MPa |
Table 6 coal body unit perpendicular stress σ
3change list in time
| t | 0 | 16h | 32h | … | 240h |
| σ 3 | 14.7MPa | 38.2MPa | 45.0MPa | … | 44.3MPa |
According to list data, with time t for transverse axis, with mining-induced stress value for the longitudinal axis, carry out curve fitting by MATLAB software, the change curve of square coal body unit mining-induced stress t in time in face of drawing, as shown in Figure 3;
Step 3, establishment axial compression loading and confined pressure unloading synchronous servo control program
Learnt by the workplace front coal body mining-induced stress rule of development under summary different exploitation condition, under mining influence, workplace front coal body experienced by and loads and the STRESS VARIATION process of confined pressure unloading from accurate hydrostatic force state to axial stress, in conjunction with correlation theory, with painted coal body element stress change curve for foundation, utilize visual c++ programming language to write axial compression loading and confined pressure unloading synchronous servo control program, import true triaxial permeability test macro Computer Control Unit;
Step 4, true triaxial permeability test macro measures coal body permeability
First, utilize boring and coring sampling method, arrange boring at workplace, drilling depth should be greater than Affected areas by mining.Samples of coal pulled, being processed into is highly 8cm, and cross-sectional area is 25cm
2rectangular parallelepiped coal body test specimen 15, be placed in vacuum drying chamber, be heated to 50 DEG C and keep constant temperature 24h, to take out after Drying and cooling and to load true triaxial permeability test bed;
Secondly, start-up simulation machine control device 16, coal body test specimen three-dimensional stress initial value sets according to the accurate hydrostatic force state in coal seam, i.e. σ
1=σ
2=σ
3=8.73MPa, then applies methane gas pressure, inlet end gas pressure P
1for coal-bed gas pressure 7.33MPa, outlet side gas pressure P
2for air pressure 0.12MPa near workplace;
Finally run, run axial compression loading and confined pressure unloading synchronous servo control program, complete the simulation of mining-induced stress mechanism within a certain period of time, after gas exit velocity is stable, gas porous flow amount is measured by Gas-Flow gauge 13, correlation parameter substitutes into following formula (1), calculates coal body test specimen permeability K value for 2.3md.
Claims (2)
1. measure a method for underground coal mine workplace front coal body permeability, it is characterized in that, comprise the following steps:
Step 1, mensuration workplace front coal body mining-induced stress, it comprises step by step following:
A utilizes computing machine that mining influence plane domain is divided into grid, and using each grid node as measuring point, move towards to arrange several boring along workplace at measuring point place, each adjacent boring is q along workplace strike separation, drilling depth be followed successively by L, L+1p, L+2p, L+3p ... L+np, wherein, L+np<100m, n is drilling hole amount, and p is for boring is along workplace horizontal direction spacing;
B preparing experiment hardware, described Experimental Hardware comprises mine monitoring stress system, and described mine monitoring stress system comprises system host, borehole stressmeter, guide pole, regulator and stabilized voltage supply;
C installs Experimental Hardware, meets step a, with guide pole, borehole stressmeter is slowly sent into boring assigned address, then injects oil pressure, and stress induction probe is initiatively coupled with coal and rock; Underground part utilizes mining communication cable to connect stabilized voltage supply, regulator, builds pressure monitoring substation; Above ground portion connected system main frame;
D starts stabilized voltage supply, and stress in coal bed is converted into the oil pressure of hydraulic oil by described borehole stressmeter, and oil pressure is converted into electric signal again, finally transfers pressure transmission to system host, and described system host is for collecting Monitoring Data and classifying to it, process;
Step 2, drafting coal body element stress change curve,
The data monitored in above-mentioned steps d are added up, makes form, describe mining-induced stress σ on coal body three directions, workplace front
1, σ
2, σ
3distribution on coal body depth direction X, binding isotherm draws mining-induced stress σ on workplace front coal body three directions then
1, σ
2, σ
3not stress value in the same time in advance of the face process, carries out record, according to list data with form, with time t for transverse axis, with mining-induced stress value for the longitudinal axis, carry out curve fitting by MATLAB software, the change curve of square coal body unit mining-induced stress t in time in face of drawing;
Step 3, establishment axial compression loading, confined pressure unloading synchronous servo control program,
With the coal body element stress change curve drawn in step 2 for foundation, utilize visual c++ programming language to write axial compression loading and confined pressure unloading synchronous servo control program, import true triaxial permeability test macro Computer Control Unit;
Step 4, true triaxial permeability test macro measure coal body permeability, and it comprises step by step following:
E makes coal body test specimen, samples of coal pulled, and being processed into is highly l, and cross-sectional area is the rectangular parallelepiped test specimen of A, is placed in vacuum drying chamber, heating, drying, obtains coal body test specimen;
F installs, and utilizes boring and coring sampling method to arrange boring at workplace, above-mentioned coal body test specimen is loaded true triaxial permeability test bed;
G starts, and start-up simulation machine control device, on described coal body three directions, mining-induced stress initial value sets according to the accurate hydrostatic force state in coal seam, i.e. σ
1=σ
2=σ
3=γ h, applies methane gas pressure, inlet end gas pressure P
1for coal-bed gas pressure, outlet side gas pressure P
2for air pressure near workplace, γ represents the unit weight of rock, and h represents the depth of burial in coal seam;
H runs, and runs axial compression loading and confined pressure unloading synchronous servo control program, completes the simulation of mining-induced stress mechanism, after gas exit velocity is stable, measure gas porous flow amount Q in time t
0, binding isotherm calculates coal body test specimen permeability K, obtains the permeability that the workplace front degree of depth is L place coal body unit.
2. the method for mensuration underground coal mine workplace front according to claim 1 coal body permeability, is characterized in that: in described step h, calculates permeability according to following formula (1):
In formula: K---permeability, md;
P
0---atmospheric pressure, MPa;
Q
0---gas porous flow amount, cm
3/ s;
μ---gas viscosity coefficient, gets 0.0158cPa;
L---coal body height of specimen, cm;
P
1---inlet end gas pressure, MPa;
P
2---outlet side gas pressure, MPa;
A---test specimen cross-sectional area, cm
2.
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| CN106404568A (en) * | 2016-10-26 | 2017-02-15 | 中国科学院武汉岩土力学研究所 | True/false-triaxial test device capable of measuring dense rock gas permeability |
| CN107130997B (en) * | 2017-06-28 | 2023-08-18 | 中国矿业大学(北京) | Technical method for mining bedding drilling and extracting pressure relief gas on working face of unequal length protective layer |
| CN107130996B (en) * | 2017-06-28 | 2023-08-18 | 中国矿业大学(北京) | Technical method for mining through-layer drilling and pressure relief gas extraction of non-equilong protective layer working face |
| CN109538297A (en) * | 2018-10-25 | 2019-03-29 | 大同煤矿集团有限责任公司 | A kind of Seam Mining stress one monitoring device |
| CN109682736A (en) * | 2018-12-26 | 2019-04-26 | 河南理工大学 | A kind of method of underground gas injection measurement coal seam anisotropy permeability coefficient |
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| CN102297831B (en) * | 2011-05-23 | 2013-04-03 | 山东科技大学 | Test device and method for rapid gas logging of permeability of coal seam |
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