On-line monitoring system for surrounding rock stress of goaf

Abstract

The invention discloses a goaf surrounding rock stress on-line monitoring system, which relates to the technical field of surrounding rock stress monitoring, and is characterized by comprising an underground roadway stress-strain testing system, a data acquisition and wireless transmission system and a data analysis early warning system, the underground roadway stress-strain test system realizes real-time monitoring of mine roadway deformation and stress change rules; the data acquisition and wireless transmission system is used for sending out data in a wireless manner, realizing a real-time automatic acquisition function, realizing real-time wireless transmission and exchange of data under a mine, and being connected with a wellhead optical cable to realize seamless connection with a ground data system; the data analysis and early warning system achieves butt joint of ground data and underground data and rapidly transmits the data to a host processor for background analysis processing, data storage and internet real-time issuing, and the synchronous early warning function of underground and ground roadway deformation and dynamic disasters is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of surrounding rock stress monitoring, and more specifically, to an online monitoring system for surrounding rock stress in a goaf area. Background Art

[0002] With the expansion of mining area and volume, mine ground pressure disasters have gradually become a common type of disaster in mining production activities. The monitoring and early warning needs for mine ground pressure disasters are more urgent.

[0003] Traditional ground pressure measurement technology is based on multiple theories such as optics, mechanics, seismology, and electromagnetism. The main technologies include photoelastic stress technology, acoustic emission technology, electromagnetic radiation technology, and in-situ rock stress testing technology. These technologies monitor the stress of mine surrounding rocks based on different theories, but their early warning function for mine ground pressure disasters is relatively lacking. Summary of the invention

[0004] The purpose of the present invention is to provide an online monitoring system for surrounding rock stress in goaf area to solve the problems existing in the prior art.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: an online monitoring system for surrounding rock stress in goaf areas, the system comprising:

[0006] Underground tunnel stress-strain testing system: Realize real-time monitoring of mine tunnel deformation and stress change patterns.

[0007] Data acquisition and wireless transmission system: It can send data wirelessly, realize the function of real-time automatic acquisition, and realize real-time wireless transmission and exchange of data in the mine, and connect with the wellhead optical cable to achieve seamless connection with the ground data system.

[0008] Data analysis and early warning system: realize the connection between surface data and underground data, and quickly transmit the data to the host processor for background analysis and processing, data preservation, real-time Internet publishing, and realize the synchronous early warning function of underground and surface tunnel deformation and dynamic disasters.

[0009] The present invention is further configured as follows: the underground tunnel stress and strain testing system includes a stress and strain testing sensor, an optical fiber cable, a wireless data transmitter, and a special universal testing anchor rod; the stress and strain testing sensor is a resistance strain gauge, and the resistance strain gauge includes a resistance wire, a substrate, a cover sheet, and a lead wire. The resistance wire is a sensitive element of the resistance strain gauge, and the substrate and the cover sheet play the role of positioning and protecting the resistance wire and insulating the resistance wire from the tested object; the lead wire is used to connect the measuring wire.

[0010] The present invention is further configured as follows: the data acquisition and wireless transmission system includes an intelligent data processing chip, a wireless data transmission module, a wireless data transmitting module, a wireless data receiving module, a wireless data repeater, a network coordinator, a display module and an optical fiber cable.

[0011] The present invention is further configured as follows: the intelligent data processing chip signal processing part and the microprocessor;

[0012] The signal processing part includes the front channel, program-controlled amplifier and A / D converter, and its function is to extract and amplify the sensor analog signal under program control and perform analog / digital conversion;

[0013] The microprocessor is responsible for controlling the operation of various components of the system and processing digital signals;

[0014] The wireless data transmission module, under the control of the microprocessor, uses the encoder to encode and process the collected information data accordingly and transmit it;

[0015] The wireless data receiving module receives the data transmitted by the radio under the control of the microprocessor and displays it through the display module.

[0016] The present invention is further configured as follows: the data analysis and early warning system includes a computer host processor, an optical fiber cable, a data storage hard disk, Internet transmission based on a B / S mode, a system data analysis and processing system, and a network early warning system.

[0017] In summary, the online monitoring system for surrounding rock stress in goaf provided by the present invention can be improved in the following aspects compared with the prior art:

[0018] (1) Computer dynamic simulation display of monitoring parameters and alarms on the well

[0019] The monitoring server and client can display the data and histogram of the monitoring point in real time. When the monitoring data exceeds the limit, it can automatically sound an alarm and record the alarm event.

[0020] (2) Automatic recording and storage of monitoring data

[0021] The well monitoring server can store data into the database according to the set recording cycle. The data adopts dynamic storage technology and the database adopts SQL massive database.

[0022] (3) The backup storage function of the substation and receiving system automatically starts the backup storage when the communication line or computer fails.

[0023] (4) Continuous monitoring curve display and analysis

[0024] The software supports historical curve and line data analysis on both the server and client sides.

[0025] (5) Comprehensive and professional analysis of monitoring data

[0026] The monitoring and analysis software integrates the prediction of surrounding rock burst and the theoretical mathematical model of mine pressure, and supports simplified and fast data analysis. Specifically, the following parts are analyzed: analysis of the stability law of surrounding rock during mining, analysis of the movement law of the roof of the survey line (or the upper, middle and lower parts), analysis of the pressure distribution of the roof of the working face, monitoring of the temperature, humidity and human-machine environment changes in the mine tunnel, analysis of the periodic pressure step and strength of the working face, analysis of the displacement change law of the surrounding rock of the tunnel, analysis of the stress change and effectiveness of the tunnel support, comprehensive warning of roof fall in the monitoring section, and multivariate parameter correlation mine health analysis and warning.

[0027] (6) Historical data query and report output

[0028] Historical data time interval query, historical curve query and output, statistical analysis, and output of comprehensive analysis reports.

[0029] (7) Tunnel stability dynamic monitoring network function

[0030] The software adopts B / S structure, supports LAN, WAN client monitoring mode and Web user browser mode data sharing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the basic structure of the resistance strain gauge in the embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of a DC bridge in an embodiment of the present invention;

[0033] Figure 3 Schematic diagram of a differential bridge in an embodiment of the present invention; (a) is a half-bridge differential circuit, and (b) is a full-bridge differential circuit;

[0034] Figure 4 This is a schematic diagram of the electrical measurement principle of the test anchor rod in an embodiment of the present invention;

[0035] Figure 5 is a design drawing of a test anchor rod in an embodiment of the present invention;

[0036] Figure 6 is a schematic diagram of wireless transmission in an embodiment of the present invention;

[0037] Figure 7 is a schematic diagram of a wireless data acquisition system in an embodiment of the present invention;

[0038] Figure 8 is a schematic diagram of the circuit of the A / D converter and the single chip microcomputer in an embodiment of the present invention;

[0039] Fig. 9 is a schematic diagram of a coded signal in an embodiment of the present invention;

[0040] Fig.10 is a schematic diagram of a data encoding timing in an embodiment of the present invention;

[0041] Fig.11 is a schematic diagram of a wireless transmission module in an embodiment of the present invention;

[0042] Fig.12 is a schematic diagram of a wireless receiving module in an embodiment of the present invention;

[0043] Fig.13 is a schematic diagram of a wireless gateway interface in an embodiment of the present invention;

[0044] Fig.14 is a schematic diagram of a B / S mode in an embodiment of the present invention;

[0045] Fig.15 It is a general layout diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0046] The following is combined with Figure 1-15 The present invention is described in further detail.

[0047] Embodiment: An online monitoring system for surrounding rock stress in goaf areas, the system comprising an underground tunnel stress and strain testing system, a data acquisition and wireless transmission system, and a data analysis and early warning system.

[0048] The underground tunnel stress and strain test system includes stress and strain test sensors, optical fiber cables, wireless data transmitters, and special universal test anchors. The system is used to monitor the deformation and stress change rules of mine tunnels in real time.

[0049] (1) Metal resistance strain gauge design

[0050] ①Basic structure of resistance strain gauge

[0051] The stress strain test sensor is a resistance strain gauge, which is mainly composed of four parts. Figure 1 As shown, the resistance wire is the sensitive element of the strain gauge; the substrate and cover sheet play the role of positioning and protecting the resistance wire, and insulate the resistance wire from the test piece; the lead wire is used to connect the measuring wire.

[0052] ②Measurement circuit of resistance strain gauge

[0053] Strain gauges can convert strain into changes in resistance. In order to display and record the size of the strain, the change in resistance must be converted into changes in voltage or current. Therefore, a dedicated measurement circuit is required, usually using a DC bridge and an AC bridge.

[0054] Since the output signal of the strain gauge bridge circuit is generally weak, the bridge output end of most current resistance strain sensors is connected to a DC amplifier, such as Figure 2 shown.

[0055] Assume that the resistance of each arm of the bridge is R1R3R2R4, which can be all or part of strain gauges. Since the input resistance of the DC amplifier is much larger than the bridge resistance, the output end of the bridge can be regarded as an open circuit. This bridge is called a voltage output bridge, and the output voltage U0 is

[0056]

[0057] ③Non-linear error and temperature compensation

[0058] The linear relationship in the above equation is obtained when the strain gauge parameter changes very little, when ΔR<<R1. If the strain gauge is subjected to too much pressure, the above assumption does not hold true, and the output voltage and strain of the bridge form a nonlinear relationship. In this case, using an instrument with a linear relationship scale for measurement will inevitably lead to nonlinear errors. In order to eliminate nonlinear errors, in practical applications, half-bridge differential or full-bridge differential circuits are often used, such as Figure 3 As shown, the nonlinear error can be improved and the output sensitivity can be increased.

[0059] The method to achieve the test is to attach the working strain gauge and the temperature compensation strain gauge to the anchor rod and the temperature compensation component respectively and connect them to the bridge in half-bridge working mode. Figure 4 As shown (R2 is the temperature compensation strain gauge, R1 is the test strain gauge).

[0060] (2) Design of special universal test anchor

[0061] In order to simulate the actual working conditions of the anchor support project, the structure of the special universal test anchor should be as similar as possible to the actual anchor used. For this purpose, we can drill a hole in the axial center of the original anchor rod body, such as Figure 5 As shown, a longitudinal resistance strain gauge is implanted into the axial center hole of the rod body, and two leg wires of the strain gauge are respectively connected to the centralized plug in the protective cover at the end of the rod. The strain gauge and wiring holes are sealed and pasted with epoxy resin glue, and then connected to the resistance strain gauge through the middle connecting line.

[0062] After the test anchor is manufactured, it is calibrated indoors. In the laboratory, the force measuring anchor is placed for more than 48 hours to simulate the humid environment on site, and then calibrated with a press, recording the strain values ​​at different tonnages, and finally drawing the stress-strain curve.

[0063] The data acquisition and wireless transmission system includes an intelligent data processing chip, a wireless data transmission module, a wireless data transmitting module, a wireless data receiving module, a wireless data repeater, a network coordinator, a display module and an optical fiber cable.

[0064] The intelligent data processing chip consists of a signal processing part and a microprocessor. The signal processing part includes the preceding channel, a programmable amplifier and an A / D converter. Its function is to extract and amplify the sensor analog signal under program control and perform analog / digital conversion. The microprocessor is responsible for controlling the operation of various components of the system and processing digital signals.

[0065] The wireless data transmission module, under the control of the microprocessor, uses the encoder to encode and process the collected information data accordingly and transmit it.

[0066] The wireless data receiving module receives the data transmitted by the radio under the control of the microprocessor and displays it through the display module.

[0067] ①Programmable amplifier

[0068] The program-controlled amplifier consists of an analog switch, an input amplifier and an interface circuit. Its function is to select the pressure signal to be sent to the amplifier input terminal under program control, and at the same time, it can also synchronously select the corresponding gain of the two signals, and output the pressure, temperature and voltage signals required by the A / D converter after amplification by the amplifier, so as to perform A / D conversion.

[0069] ②A / D converter

[0070] The POL terminal of ICL7135 is the polarity output terminal. When the input signal is positive, POL outputs a high level; when the input signal is negative, POL outputs a low level. B1, B2, B4, and B8 are BCD code output terminals. The accuracy and stability of the reference voltage of the A / D converter are the main factors affecting the conversion accuracy. In order to ensure the conversion accuracy of ICL7135, a high-accuracy, low-temperature drift bandgap reference voltage source MC1403 is used to provide it with a 1V reference voltage. The basic connection between the A / D converter and the microcontroller is shown in Figure 8 .

[0071] ③Wireless data transmission module

[0072] The wireless data transmission module consists of an encoder and a transmission module. The encoder is a low-power, low-cost universal encoding circuit manufactured by CMOS technology, which can compile data and addresses into code waveforms. It has a maximum of 12 bits (A0~A11) of three-state address pins (suspended, connected to high level, connected to low level), with a total of 531441 address codes. There are a maximum of 6 bits (D0~D5) of data pins, and the set address code and data code are serially output from pin 17. The signal format is as follows: Fig. 9As shown, the encoding timing is as follows Fig.10 shown.

[0073] The transmitting module has a wide operating voltage range and low power consumption. When the transmitting voltage is 3V, the transmitting current is about 2mA, and the transmitting power is small. 12V is the best operating voltage, with a good transmitting effect. The transmitting current is about 5-8mA. When the DC power consumption is greater than 12V, the effective transmitting power is no longer significantly increased. The F05 series uses AM modulation to reduce power consumption. The data signal stops and the transmitting current drops to zero. The data level should be close to the actual working voltage of F05 to obtain a higher modulation effect. F05 is prone to reduce the modulation efficiency for overly wide modulation signals, and the receiving and sending distance becomes closer. When the high-level pulse width is between 0.08 and 1ms, the transmitting effect is better. After it is greater than 1ms, the efficiency begins to decrease; when the low-level area is greater than 10ms, the first bit of the received data is easily interfered with (i.e., zero-level interference) and causes non-decoding. If CPU encoding is used, some garbled codes can be added before the data recognition bit to suppress zero-level interference. If it is a universal codec, the oscillation resistor can be adjusted to make the low-level area in the middle of each group of codes less than 10ms. Normally, the F05 input terminal should be in a low level state, the input data signal should be a positive logic level, and the maximum amplitude should not exceed the working voltage of F05. F05 should be installed vertically on the edge of the printed circuit board and should be at least 5mm away from surrounding devices to avoid being affected by distributed parameters and stopping vibration. Fig.11 .

[0074] ④Wireless data receiving module

[0075] The wireless data receiving module is mainly composed of the PT2272 decoder and the J05 receiving module. The PT2272 can have up to 12 bits (A0~A11) of three-state address pins, any combination of which can provide 531441 address codes, up to 6 bits (D0~D5) of data output pins, and pin 17 is the decoding valid indication output. The PT2272 is divided into latched output or non-latched output.

[0076] The J05 receiving module adopts a superheterodyne and secondary frequency conversion structure. All RF reception, mixing, filtering, data demodulation, amplification and shaping are completed in the chip, and the receiving function is highly integrated. There are two working modes to choose from to suit the demodulation of different data rates. When the third pin is left floating (internally pulled up to a high level), the RF receiving bandwidth is wider and can adapt to transmitters stabilized by SAW resonators with large transmission frequency accuracy errors and general LC transmitters. When the third pin is grounded, the RF receiving bandwidth is narrower and the demodulation filter bandwidth is larger, but the matching transmitter must have higher frequency accuracy and stability, and the transmission frequency must be stabilized by a crystal or a high-precision SAW resonator. See the receiving circuit for details. Fig.12 .

[0077] The antenna interface and the sensor network antenna interface have been connected to ensure that the sensor network signal can be reliably transmitted to the network server. At the same time, the power supply adopts the standard AC 220V voltage to ensure the stability and reliability of the equipment. Buttons and indicator lights are also indispensable components of the equipment. Two sets of indicator lights are used, operation and link indicator lights, to indicate the operating status of the network and the equipment.

[0078] In addition, the wireless gateway also has 2 sets of photoelectrically isolated analog input ports, 2 sets of photoelectrically isolated analog output ports, 2 sets of photoelectrically isolated digital input ports, 2 sets of photoelectrically isolated digital output ports, as well as standard RS232 communication interface, RS485 communication interface, CAN communication interface, and LAN communication interface for connecting with other wired devices.

[0079] The wireless gateway is responsible for transmitting the received wireless data to the computer through the computer interface for storage, analysis and processing. The gateway series provides USB and Ethernet, which can be connected to the local computer or remotely transmitted through INTENET / other wireless networks.

[0080] Data analysis and early warning system: realize the connection between surface data and underground data, and quickly transmit the data to the host processor for background analysis and processing, data preservation, real-time Internet publishing, and realize the synchronous early warning function of underground and surface tunnel deformation and dynamic disasters.

[0081] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. An online monitoring system for surrounding rock stress in goaf area, characterized by: The system comprises: Underground tunnel stress and strain testing system: to achieve real-time monitoring of mine tunnel deformation and stress change law; Data acquisition and wireless transmission system: It can send data wirelessly, realize the function of real-time automatic acquisition, and realize the real-time wireless transmission and exchange of underground mine data, and connect with the wellhead optical cable to achieve seamless connection with the ground data system; Data analysis and early warning system: realize the connection between surface data and underground data, and quickly transmit the data to the host processor for background analysis and processing, data preservation, real-time Internet publishing, and realize the synchronous early warning function of underground and surface tunnel deformation and dynamic disasters.

2. The online monitoring system for surrounding rock stress in goaf area according to claim 1 is characterized by: The underground tunnel stress and strain testing system includes a stress and strain testing sensor, an optical fiber cable, a wireless data transmitter, and a special universal testing anchor rod; The stress strain test sensor is a resistance strain gauge, which includes a resistance wire, a substrate, a cover sheet and lead wires. The resistance wire is the sensitive element of the resistance strain gauge. The substrate and the cover sheet play the role of positioning and protecting the resistance wire and insulating the resistance wire from the test piece; the lead wire is used to connect the measuring wire.

3. The online monitoring system for surrounding rock stress in goaf area according to claim 1 is characterized by: The data acquisition and wireless transmission system includes an intelligent data processing chip, a wireless data transmission module, a wireless data transmitting module, a wireless data receiving module, a wireless data repeater, a network coordinator, a display module and an optical fiber cable.

4. The online monitoring system for surrounding rock stress in goaf area according to claim 3 is characterized by: The intelligent data processing chip signal processing part and microprocessor; The signal processing part includes the front channel, program-controlled amplifier and A / D converter, and its function is to extract and amplify the sensor analog signal under program control and perform analog / digital conversion; The microprocessor is responsible for controlling the operation of various components of the system and processing digital signals; Under the control of the microprocessor, the wireless data transmission module encodes and processes the collected information data accordingly and transmits it; The wireless data receiving module receives the data transmitted by the radio under the control of the microprocessor and displays it through the display module.

5. The online monitoring system for surrounding rock stress in goaf area according to claim 1 is characterized by: The data analysis and early warning system includes a computer host processor, an optical fiber cable, a data storage hard disk, Internet transmission based on a B / S mode, a system data analysis and processing system, and a network early warning system.

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