CN114113224B - Microcurrent testing system and method under concentrated stress of coal and rock - Google Patents
Microcurrent testing system and method under concentrated stress of coal and rock Download PDFInfo
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- CN114113224B CN114113224B CN202111436767.5A CN202111436767A CN114113224B CN 114113224 B CN114113224 B CN 114113224B CN 202111436767 A CN202111436767 A CN 202111436767A CN 114113224 B CN114113224 B CN 114113224B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/30—Assessment of water resources
Abstract
The invention discloses a micro-current testing system and a micro-current testing method under coal and rock concentrated stress. The microcurrent testing method under the concentrated stress of the coal and rock can be used for collecting current signals in the deformation and damage process of the concentrated load coal and rock sample, abnormal signals caused by friction, dislocation and falling of electrodes can be avoided, interference signals in the environment can be greatly reduced, the current response rule of the concentrated stress change process of the coal body in front of the stoping face is further simulated, and technical support is provided for researching the mechanical characteristics and the current change rule of the coal and rock loading and damage process.
Description
Technical Field
The invention relates to a micro-current monitoring system and a method in a coal rock deformation and damage process, in particular to a micro-current testing system and a method under concentrated stress of coal rock.
Background
Coal rock dynamic disasters such as rock burst and coal and gas outburst are accompanied in the coal mining process, personnel casualties and property loss are often caused, the coal mine safety and high-efficiency production are seriously threatened, and the monitoring and early warning of the rock burst are effective means for preventing the disasters. The geophysical method has the advantages of nondestructive detection, high efficiency, convenience, low cost and the like, and plays an increasingly important role in coal and rock dynamic disaster monitoring in recent years. Experimental research shows that the coal and the rock can excite micro-current in the loading process, the intensity of excitation current is closely related to stress, deformation, fracture and the like of the coal and the rock, and the change of the excitation current can reflect the stress and internal damage condition of the coal and the rock. In the coal seam exploitation process, a stress relaxation area, a stress concentration area and an original stress area are sequentially formed in front of a working face, and dynamic disasters are easier to occur in the stress concentration area, so that the method is a key area for monitoring dynamic disasters.
At present, the method adopted for testing the microcurrent of the loading process of the coal rock in the laboratory is to paste electrodes on the surface of a standard sample, load the sample integrally and shield the sample by using a shielding net. The method has the following defects: (1) Compression, expansion, fracture and the like of a coal rock sample in the loading process can cause the phenomena of friction, dislocation, electrode falling and the like between the surface of the sample and an electrode sheet, and generate a plurality of abnormal currents; (2) The relationship between the current flow direction and the stress gradient cannot be determined; (3) The current response rule of the concentrated stress change process of the coal body in front of the stope face cannot be simulated; (4) The signal transmission line passes through the shielding net to influence the shielding effect, so that more interference signals enter.
Disclosure of Invention
The invention aims to: aiming at the technical defects, the microcurrent testing system and method for the coal and rock loading process, which have simple structure and convenient operation, can simulate and monitor the excitation current change rule under the concentrated stress of the coal and rock, and can effectively inhibit the generation of interference signals.
The technical scheme is as follows: the micro-current testing system under the concentrated stress of the coal and the rock comprises an electromagnetic shielding system, a loading system and a micro-current acquisition system, and mainly comprises an electromagnetic shielding chamber, a signal adapter plate, a filter tube, a micro-control servo press, a press control console, an insulating gasket, a stainless steel cushion block, an electrometer, a radio frequency connecting wire, an electric signal data transmission line and a computer; the micro-control servo press is arranged in the electromagnetic shielding chamber and is connected with a press control console outside the electromagnetic shielding chamber through a cable and an oil pipe which pass through the filter tube; the electrometer is arranged outside the electromagnetic shielding chamber and is connected with a signal adapter plate on the electromagnetic shielding chamber through a radio frequency connecting wire; one end of the electric signal data transmission line is connected with the signal adapter plate, and the other end of the electric signal data transmission line is connected with the copper electrode plate.
Further, the signal adapter plate comprises a wood plate with holes, a 300-mesh copper net and a triaxial BNC adapter, wherein the copper net covers two sides of the wood plate, and the triaxial BNC adapter is fixed with the wood plate through small holes and is in close contact with the copper net; the radio frequency connecting wire is a shielding cable, and three coaxial BNC interfaces are connected to two ends of the radio frequency connecting wire.
Further, the microcurrent is collected by using a copper electrode plate, the copper electrode plate is stuck on the surface of one end of the non-loaded part of the sample, the copper electrode plate is stuck on the surface of a stainless steel cushion block, the copper electrode plate is coupled with the sample and the stainless steel cushion block by using conductive adhesive, and the copper electrode plate is fixed by using an insulating adhesive tape.
Further, one end of the current data transmission line is connected with a BNC interface, the current data transmission line is connected with a triaxial BNC adapter on the signal adapter plate, the positive electrode of the tail end is connected with the copper electrode plate, the negative electrode is connected with the copper electrode plate, and the shielding electrode is connected in an empty mode.
Further, the copper electrode plate is connected with a grounding port on the shielding chamber through a wire, and the grounding port is grounded.
Further, an insulating gasket is paved on the press workbench, and the insulating gasket is arranged between the stainless steel cushion block and the pressure head.
Further, the computer is connected with the electrometer and is used for displaying, storing and processing current data.
A testing method of a micro-current testing system under concentrated stress of coal and rock comprises the following steps:
the first step: assembling a microcurrent testing system under the concentrated stress of the coal rock;
and a second step of: firstly, placing an insulating gasket on a press workbench, placing a coal rock sample on the insulating gasket, and adjusting the sample to enable a loaded part of the sample to be positioned at the center of the press workbench; then, respectively attaching a copper electrode plate and a copper electrode plate to the surface of the non-loaded side of the sample and the surface of the stainless steel cushion block through conductive adhesive, and fixing by using an insulating adhesive tape; placing a stainless steel cushion block at the upper end of the loaded part of the sample, adjusting the stainless steel cushion block to enable the center of the stainless steel cushion block to be positioned on the same axis with the center of a working table of a press, and then placing an insulating gasket on the stainless steel cushion block;
and a third step of: after the arrangement of the insulating gasket, the sample, the electrode and the stainless steel cushion block is completed, connecting the anode of the electric signal data transmission line to the copper electrode sheet, connecting the cathode to the copper electrode sheet and connecting the electrode of the shielding layer to the air;
fourth step: after the electric signal data transmission line is connected with the electrode, firstly, a micro-control servo press and an electrometer are opened, then, the press is adjusted to enable the pressure head to be in slight contact with the upper insulating gasket, the load is increased to 10N at the speed of 0.1 mm/min, and the current is waited to recover stably;
fifth step: after the current is stable, loading the sample according to a test scheme, and collecting a current signal at the same time;
sixth step: after the coal rock sample is crushed, closing the micro-control servo press and the electrometer, taking down a copper electrode plate on the sample, removing a stainless steel cushion block and an insulating cushion block, and cleaning the sample;
seventh step: and (3) after the test is completed, disassembling the device and finishing the instrument.
The beneficial effects are that: the microcurrent testing system and method under the concentrated stress of the coal and rock can collect microcurrents in the deformation and damage process of the concentrated load coal and rock sample, can avoid abnormal signals caused by friction, dislocation and falling of electrodes, can greatly reduce interference signals in the environment, further realize the current response rule of the concentrated stress change process of the coal body in front of a stoping face, and provide technical support for researching the mechanical characteristics and the current change rule of the coal and rock loading and damage process.
Drawings
FIG. 1 is a schematic diagram of a microcurrent testing system under concentrated stress of coal and rock;
fig. 2 is a schematic diagram of a signal patch panel.
Detailed Description
The invention will be further described with reference to the accompanying drawings.
As shown in FIG. 1, the micro-current testing system under the concentrated stress of coal and rock comprises an electromagnetic shielding chamber 1, a signal adapter plate 2, a filter tube 3, a micro-control servo press 4, a press control console 7, an insulating gasket 8, a stainless steel cushion block 13, an electrometer 15, a radio frequency connecting wire 16, an electric signal data transmission line 17 and a computer 20; the micro-control servo press 4 is arranged in the electromagnetic shielding chamber 1 and is connected with a press control console 7 outside the electromagnetic shielding chamber 1 through a cable 5 and an oil pipe 6 which pass through the filter tube 3; the micro-control servo press 4 and the stainless steel cushion block 13 are used for applying concentrated load to the sample, and the press control console 7 is used for controlling the micro-control servo press 4; the electrometer 15 is arranged outside the electromagnetic shielding chamber 1 and is connected with the signal adapter plate 2 on the electromagnetic shielding chamber 1 through a radio frequency connecting wire 16; one end of the electric signal data transmission line 17 is connected with the signal adapter plate 2, the positive electrode of the tail end is connected with the copper electrode plate 11, the negative electrode is connected with the copper electrode plate 12, and the shielding electrode is connected in a space; the electrode plate 12 is connected with a grounding port 19 on the electromagnetic shielding chamber 1 through a lead 18, and the grounding port 19 is grounded; the computer 20 is connected to the electrometer 15 for display, storage and processing of current data.
As shown in fig. 1, the signal patch panel 2 includes a board 21 with holes, a 300 mesh copper net 22, and a triaxial BNC adapter 23, the 300 mesh copper net 22 covers both sides of the board 21 with holes, and the triaxial BNC adapter 23 is fixed to the board 21 through small holes and is in close contact with the copper net 22.
A testing method of a micro-current testing system under concentrated stress of coal and rock comprises the following steps:
the first step: assembling a microcurrent testing system under the concentrated stress of the coal rock;
and a second step of: firstly, placing an insulating gasket 8 on a press workbench 9, placing a sample 10 on the insulating gasket 8, and adjusting the sample 10 to enable a loaded part of the sample to be positioned at the center of the press workbench 9; then the copper electrode plate 11 and the copper electrode plate 12 are respectively stuck on the surface of the non-loaded side of the sample 10 and the surface of the stainless steel cushion block 13 through conductive adhesive, and are fixed by insulating adhesive tapes; placing a stainless steel cushion block 13 at the upper end of the loaded part of the sample 10, adjusting the stainless steel cushion block 13 to enable the center of the stainless steel cushion block to be positioned at the same axis with the center of a press workbench, and placing an insulating gasket 8 on the stainless steel cushion block 13;
and a third step of: the positive electrode of the electric signal data transmission line 17 is connected with the copper electrode plate 11, the negative electrode is connected with the copper electrode plate 12, and the shielding layer electrode is connected with the air;
fourth step: firstly, the micro-control servo press 4 and the electrometer 15 are opened, then the micro-control servo press 4 is adjusted to enable the pressure head 14 to be in slight contact with the upper insulating gasket 8, the load is increased to 10N at the speed of 0.1 mm/min, and the current is waited for to recover stably;
fifth step: after the current is stable, loading the sample according to a test scheme, and collecting a current signal at the same time;
sixth step: after the coal rock sample is crushed, the micro-control servo press 4 and the electrometer 15 are closed, the copper electrode plate 11 on the sample 10 is taken down, the stainless steel cushion block 13 and the insulating gasket 8 are removed, and the crushed sample is cleaned;
seventh step: and (3) after the test is completed, disassembling the device and finishing the instrument.
Claims (2)
1. A microcurrent testing system under concentrated stress of coal and rock is characterized in that: the electromagnetic shielding system comprises an electromagnetic shielding system, a loading system and a micro-current acquisition system, wherein the loading system comprises a micro-control servo press (4) arranged in an electromagnetic shielding chamber (1), a press control console arranged outside the electromagnetic shielding chamber (1), the current acquisition system comprises an electrometer (15) and an acquisition line, the electrometer is arranged outside the electromagnetic shielding chamber (1), the electromagnetic shielding system comprises a signal adapter plate (2), and the signal adapter plate comprises a board with a drilling hole (21), a copper net (22) and a triaxial BNC adapter (23); the copper net (22) covers two sides of the wood board (21) with the holes, the triaxial BNC adapter (23) penetrates through the copper net (22) to be fixed in the holes, two sides of the copper net are symmetrical, the copper net is kept compact, and the electrometer (15) is connected with the signal adapter plate (2) on the electromagnetic shielding chamber (1) through the radio frequency connecting wire (16); one end of an electric signal data transmission line (17) is connected with the signal adapter plate (2), the other end of the electric signal data transmission line is connected with the first copper electrode plate (11) and the second copper electrode plate (12) respectively, the positive electrode of the electric signal data transmission line (17) is connected with the first copper electrode plate (11), the negative electrode is connected with the second copper electrode plate (12), and the shielding electrode is in air connection; the second copper electrode plate (12) is connected with a grounding port (19) through a lead (18), and the grounding port (19) is grounded; the testing system also comprises a filter tube (3), a micro-control servo press (4), a press control console (7), an insulating gasket (8), a stainless steel cushion block (13) and a computer (20); the micro-control servo press is connected with a press control console (7) outside the electromagnetic shielding chamber (1) through a cable (5) and an oil pipe (6) which pass through the filter tube (3); the press control console (7) is used for controlling the micro-control servo press (4) and displaying, storing and processing mechanical parameter data; the computer (20) is connected with the electrometer (15) and is used for displaying, storing and processing microcurrent data; the micro-control servo press (4) and the stainless steel cushion block (13) are used for applying concentrated load to the sample (10); the first copper electrode plate (11) and the second copper electrode plate (12) are respectively stuck on the surface of the non-loaded end of the sample (10) and the side surface of the stainless steel cushion block (13) through conductive adhesive, and are fixed by using insulating adhesive tapes; the sample (10) is placed on the insulating gasket (8) laid on the press workbench (9), the stainless steel cushion block (13) is placed above the loaded end of the sample (10), and the other insulating gasket (8) is placed on the stainless steel cushion block (13).
2. A method for testing a microcurrent testing system under concentrated stress of coal and rock, which is characterized by comprising the following steps:
firstly, placing an insulating gasket (8) on a press workbench (9), placing a coal rock sample (10) on the insulating gasket (8), and adjusting the sample (10) to enable a loaded part of the sample to be positioned at the center of the press workbench (9); then, respectively sticking a first copper electrode plate (11) and a second copper electrode plate (12) on the surface of the non-loaded side of the sample (10) and the surface of the stainless steel cushion block (13) through conductive adhesive, and fixing by using insulating adhesive tape; placing a stainless steel cushion block (13) at the upper end of a loaded part of a sample (10), adjusting the stainless steel cushion block (13) to enable the center of the stainless steel cushion block to be positioned at the same axis with the center of a press workbench (9), and placing another insulating gasket (8) on the stainless steel cushion block (13);
connecting an electric signal data transmission line (17) with a triaxial BNC adapter (23) on a signal adapter plate (2), and then connecting the positive electrode of the electric signal data transmission line (17) to a first copper electrode plate (11), connecting the negative electrode to a second copper electrode plate (12) and connecting the electrodes of a shielding layer in an empty way;
opening a micro-control servo press (4) and an electrometer (15), then adjusting the micro-control servo press (4) to enable a pressure head (14) to be in slight contact with an upper insulating gasket (8), and then adjusting the load to 10N at the speed of 0.1 mm/min, and waiting for current to recover stably;
after the current is stable, loading the sample (10) according to a test scheme, collecting the current at the same time, and storing current data in a computer (20);
after the coal rock sample is crushed, the micro-control servo press (4) and the electrometer (15) are closed, a first copper electrode plate (11) on the sample is taken down, a stainless steel cushion block (13) and an insulating gasket (8) are removed, and the sample (10) is cleaned.
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| CN202111436767.5A CN114113224B (en) | 2021-11-30 | 2021-11-30 | Microcurrent testing system and method under concentrated stress of coal and rock |
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| CN202111436767.5A CN114113224B (en) | 2021-11-30 | 2021-11-30 | Microcurrent testing system and method under concentrated stress of coal and rock |
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| CN114113224B true CN114113224B (en) | 2023-07-07 |
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2021
- 2021-11-30 CN CN202111436767.5A patent/CN114113224B/en active Active
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| US6344978B1 (en) * | 1997-04-11 | 2002-02-05 | Advantest Corporation | Shield case including a material giving a large transmission loss to a radio frequency signal |
| US6477061B1 (en) * | 1998-03-23 | 2002-11-05 | Amesbury Group, Inc. | I/O port EMI shield |
| CN106813976A (en) * | 2017-01-16 | 2017-06-09 | 中国矿业大学 | A kind of standard coal rock sample product fracturing process seismoelectric magnetic effect synchronous monitoring device and method |
| CN107548274A (en) * | 2017-08-31 | 2018-01-05 | 中国冶集团有限公司 | One discharge plate cabinet incoming line screening arrangement and method |
| CN107843639A (en) * | 2017-10-24 | 2018-03-27 | 中国矿业大学 | A kind of coal containing methane gas power destruction process electric potential signal test system and method |
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