CN110596461A - Embedded digital intelligent drilling resistivity tester - Google Patents
Embedded digital intelligent drilling resistivity tester Download PDFInfo
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- CN110596461A CN110596461A CN201910884668.XA CN201910884668A CN110596461A CN 110596461 A CN110596461 A CN 110596461A CN 201910884668 A CN201910884668 A CN 201910884668A CN 110596461 A CN110596461 A CN 110596461A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/02—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with propagation of electric current
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Abstract
The invention discloses an embedded digital intelligent drilling resistivity tester, which comprises an electrode power supply module, a signal acquisition module, an MCU module, an upper computer module and a probe; the electrode power supply module is used for selecting a voltage and frequency adjustable power supply; the signal acquisition module is a signal acquisition circuit based on MCU control, and realizes current, voltage and phase difference value measurement; the upper computer module is an interactive upper computer based on RaspberryPi, a user realizes interaction with the MCU through an LCD touch screen, and data can be copied out by using a U disk or transmitted to a private cloud through the 4G module after data measurement is finished; the probe comprises two parts, namely an electrode and a data transmission cable. The invention realizes adjustable power supply voltage and frequency and wider data acquisition range; phase difference measurement can be realized; the data acquisition efficiency is ensured; the data acquisition of multiple device forms and multiple parameters is realized, and the data acquisition precision is improved.
Description
Technical Field
The invention belongs to the field of engineering geophysical exploration instruments, relates to an embedded digital intelligent borehole resistivity tester, and particularly relates to an in-borehole resistivity tester for rock and soil. Specifically, the instrument is used for testing parameters such as apparent resistivity, phase, natural potential and the like of strata at different depths in a borehole in various device modes so as to accurately obtain a curve of each test parameter changing along with the depth of the strata.
Background
The resistivity of the rock-soil mass is one of important parameters for representing the electrical conductivity of the rock-soil mass, can reflect certain basic physical properties and engineering properties of the rock-soil mass, and has important theoretical significance and application value in the aspects of judging the physical and mechanical properties of the rock-soil mass, liquefaction of sandy soil, soil pollution characteristics, even microstructure morphology and the like. In the electric power engineering, effective grounding design is required according to the resistivity of soil so as to effectively reduce electric leakage and lightning disasters. The method for judging the corrosivity of foundation soil to a steel structure by utilizing the soil resistivity is also listed in the current national standard geotechnical engineering investigation Specification (GB50021-2017), and can be used for comprehensively classifying and evaluating the building site foundation by combining the results of the ground pulsation and shear wave velocity tests.
In the actual engineering investigation process, the resistivity test of the rock soil is easy to carry out on the surface of the foundation. Firstly, the earth surface testing technology is mature and the construction speed is high; secondly, the earth surface testing instruments are various in types and strong in selectivity. But the surface detection depth is easily limited by the test site, and the test effect is good in the environment of shallow foundation burial depth, good surface condition and wide site. However, when the conditions that the range of a test site is limited, the earth surface is hardened to cause extremely difficult distribution, the earth resistance is too large due to shallow miscellaneous filling and the like are met, the earth surface resistivity test is difficult, the detection depth and precision are difficult to meet the requirements, the test result can also seriously influence the evaluation result, and further potential safety hazards are brought to engineering projects and structures.
Under the background, research and development of resistivity tests in boreholes become more important, and the dilemma of surface resistivity tests can be effectively avoided by directly testing rock and soil bodies at different depths in test boreholes, so that more accurate test data can be obtained. But the resistivity test in the hole also faces the self-difficult problem, firstly, the resistivity test in the hole belongs to the problem of full-space detection, and the data processing is different from the surface test; secondly, the capacitance characteristic of the rock-soil body can respond to the power supply current, thereby influencing the measurement precision. And thirdly, the wall of the test hole is protected by mud, the current mainly flows along the direction with smaller resistivity, and the current is difficult to penetrate into the soil body to obtain more real soil layer test parameters.
Disclosure of Invention
The invention aims to provide an embedded digital intelligent drilling resistivity tester, aiming at solving the problems, the embedded digital intelligent drilling resistivity tester is brand-new designed and improved from the aspects of a power output module, a signal acquisition module, a sensor probe and the like, and realizes multi-device form and multi-parameter data acquisition and processing on the basis of ensuring the data acquisition efficiency through one-key arrangement so as to improve the data acquisition precision.
An embedded digital intelligent drilling resistivity tester comprises an electrode power supply module, a signal acquisition module, an MCU module, an upper computer module and a probe, wherein a frequency conversion method and an adjustable electrode are selected as a rock and soil resistivity measuring method.
The STM32F407 is used as a core to design variable frequency power supply current, so that the influence of the capacitance characteristic of the rock-soil body on the current is reduced; a multi-range current and voltage acquisition circuit is designed, and different ranges can be selected according to the actual situation of a test site so as to improve the measurement accuracy; the power supply and the signal acquisition circuit are controlled by the MCU, and the MCU and the upper computer realize instruction interaction through a serial port; the graphical interface of the upper computer developed based on RaspberryPi is simple and clear, and is convenient for users to use; by building a private cloud platform, storage and sharing of a large amount of data of a user can be achieved, and detailed description is given below.
The electrode power supply module selects a power supply with adjustable voltage and frequency. The digital voltage boosting device specifically comprises a lithium battery, a digital voltage boosting module and an inverter module. The measurement of the resistivity and the ground resistance of the rock-soil body requires an external power supply to supply power to the rock-soil to be measured, an electrode power supply is supplied by a lithium battery, the digital adjustable boosting module is used for realizing the wide-range adjustment of voltage, and a direct-current power supply is converted into a symmetrical square wave with adjustable frequency through an inversion module to supply power to the electrode.
Furthermore, in order to avoid short circuit of the inverter after power-on, a switch circuit is added at the front end of the inverter module, so that the MCU can control the on-off of the electrode power supply.
The signal acquisition module is a signal acquisition circuit based on MCU control, and realizes current, voltage and phase difference value measurement. The signal acquisition module specifically comprises a comparator, a current acquisition circuit, a voltage acquisition circuit and an AD conversion module; the acquisition of analog quantity is realized through a voltage and current acquisition circuit, and then an analog signal is converted into a digital signal by using an AD conversion module; when an alternating current power supply is used as a power supply, the difference of voltage and current phases can be caused by the capacitive reactance characteristics of rock and soil masses, so that the phase difference measurement is realized through hardware, an analog signal is converted into a square wave signal by connecting a voltage comparator behind a voltage and current acquisition circuit, and then the phase difference measurement is realized by using MCU external interruption and a timer.
The current acquisition circuit is mainly realized by Hall current sensors, and three Hall current sensors with different measuring ranges are selected; wherein the three measuring ranges are respectively 10mA, 1A and 15A; the channel selection of the three ranges is realized by adopting an electromagnetic relay.
The voltage acquisition circuit is realized by adopting a voltage division method.
The MCU module realizes communication with the AD conversion module through the SPI to carry out control of voltage and current measurement and data acquisition. The MCU captures the square wave signal output by the comparator module through external interruption to realize the measurement of the phase difference value; the MCU outputs two paths of inverse PWM waves to realize the control of the inversion module; and the UART and the upper computer graphical interface are used for realizing the transmission of configuration instructions and data.
The upper computer module is based on a RaspberryPi interactive upper computer. The user realizes the interaction with the MCU through the LCD touch screen; after the data measurement is finished, the data can be copied out by using a USB flash disk, and the data can be transmitted to a private cloud through a 4G module.
The probe is provided. The electrode comprises electrodes and a data transmission cable, wherein the electrodes are A, B, M, N four copper electrodes and are positioned at the bottom end of the data transmission cable, and the four electrodes are respectively provided with a lead which is led out from the top end of the data transmission cable and connected with a signal acquisition module through a plug-in interface.
The invention relates to an embedded digital intelligent drilling resistivity tester, which has the advantages and effects that: the power supply module realizes the adjustability of power supply voltage and frequency and wider data acquisition range; through the signal acquisition module, the difference of voltage and current phases caused by the capacitive reactance characteristic of the rock-soil body is avoided to the greatest extent, and the phase difference measurement is realized; one-key setting of acquisition parameters is realized through the upper computer module, so that the data acquisition efficiency is ensured; through the data acquisition and transmission cable, the data acquisition of multiple device forms and multiple parameters is realized, and the data acquisition precision is improved.
Drawings
FIG. 1 is a block diagram of an embedded digital intelligent borehole resistivity tester according to the present invention.
Fig. 2 is a structural diagram of the data acquisition device of the present invention.
Fig. 3 is a structural view of an electrode power supply module according to the present invention.
Fig. 4 is a diagram showing a signal acquisition circuit according to the present invention.
Fig. 5 is a schematic structural diagram of the electrode part of the probe according to the invention.
Fig. 6 is a diagram showing a structure of a host computer according to the present invention.
Detailed Description
The technical solution of the present invention is further described with reference to the accompanying drawings and specific embodiments.
As shown in fig. 1, an embedded digital intelligent drilling resistivity tester comprises five parts, namely an electrode power supply module, a signal acquisition module, an MCU module, an upper computer module and a sensor probe module, wherein the four parts can be collectively called as a data acquisition device; the invention selects a frequency conversion method and an adjustable electrode as a rock-soil resistivity measuring method.
A first part: data acquisition device
The hardware system of the data acquisition device is the core of the embedded digital intelligent drilling resistivity tester, and the hardware design of the data acquisition device is completed according to the rock resistivity measurement method and the resistance measurement method. The data acquisition device consists of an electrode power supply module, a signal acquisition module, an MCU module and a probe, and is shown in figure 2.
The electrode power supply module comprises a lithium battery, a digital boosting module and a hardware implementation of an inverter module; the signal acquisition module is subdivided into a hardware design of a current and voltage acquisition circuit, an AD acquisition module and a comparator module; the MCU module realizes communication with the AD conversion module through the SPI to carry out control of voltage and current measurement and data acquisition; the probe includes an electrode and a transmission cable. Wherein, the 5V voltage-stabilizing module belongs to the electrode power supply and is used as voltage-stabilizing output in the electrode power supply part.
STM32F407 is selected as a main control chip by the data acquisition device system, and the chip adopts CortexTMM4 as the 32-bit processor of its kernel.
The MCU module realizes the normal work of the MCU by designing a minimum system, and the minimum system comprises a power supply circuit, a reset circuit, a debugging interface, a clock system and a USB downloading circuit.
As shown in fig. 3, the electrode power supply is powered by a lithium battery, a wide-range voltage output is realized by using a digital boost module, and when a user uses the geotechnical-electrical prospecting instrument, the output voltage can be set according to actual conditions, so that the application field of the device can be expanded; then, a direct-current power supply is converted into a dual-array square-wave power supply with adjustable frequency through an inversion module, a user can adjust the power supply frequency according to actual conditions so as to research rock and soil resistivity more deeply, and the output frequency adjustment of the inversion module is realized by PWM (pulse-width modulation) waves output by an MCU (microprogrammed control unit); in order to avoid short circuit of the inverter after power-on, a switching circuit is added at the front end of the inverter module, so that the MCU can control the on-off of the electrode power supply. The switching circuit uses the MOS tube as a switch, the MCU and the large current are isolated by using the photoelectric coupling chip, and when the MCU outputs a low level corresponding to the control IO, the photoelectric coupling chip is conducted, so that the MOS tube is driven to be conducted.
As shown in fig. 4, the signal acquisition module is used for measuring the difference values of current, voltage and phase, the current acquisition circuit is implemented by using different hall current sensors, the measurement of rock resistivity and ground resistance requires a voltmeter to have a large internal resistance, and the resistance voltage division method can meet the requirement of high internal resistance. After analog signals obtained by the Hall sensor and the sampling resistor pass through the conditioning circuit, the analog signals can be converted into digital signals by using an AD (analog-to-digital) chip and transmitted to the MCU, and corresponding voltage values and current values can be calculated after calibration; when the symmetrical square wave is used as an electrode power supply, the comparator is designed to convert an analog signal output by the conditioning circuit into a square wave signal, and external interruption and a timer in the MCU are used for measuring the phase difference value of voltage and current.
The current acquisition circuit is mainly realized by a Hall current sensor, in order to improve the measurement accuracy, three Hall current sensors with different measuring ranges are selected, the three measuring ranges are respectively 10mA, 1A and 15A, and the types of the three Hall sensors are respectively CHV-25P, HBC1AS5 and HBC15 SY. The channel selection of the current acquisition circuit in three ranges is realized by adopting an electromagnetic relay, the electromagnetic relay is driven by a BC546A triode, and meanwhile, a photoelectric isolation chip TLP281 is added to isolate the MCU from the triode driving circuit; meanwhile, a freewheeling diode is added in the triode driving circuit, so that the accumulation of charges in the electromagnetic relay is avoided, the electromagnetic relay is damaged due to the excessive charges accumulated in the coil, and an LED lamp is arranged for indicating the on-off of the electromagnetic relay;
the voltage acquisition circuit is realized by a voltage division method, in order to improve the accuracy of voltage measurement, the voltage acquisition circuits with two measuring ranges of 15V and 150V are designed, and the sampling resistance values of the two channels are different from the gain multiple of the conditioning circuit.
The comparator module converts the output waveforms of the voltage and current acquisition circuits into square wave signals by using a plurality of voltage comparators, and then the phase difference value of the voltage and the current can be measured by mutually matching the external interrupt of the MCU with the timer. The voltage comparator is built by using an AD820AR operational amplifier, wherein the output bias of the Hall current sensor with the range of 1A is 2.5V, so that a voltage division circuit consisting of a slide rheostat and a resistor is added at the comparison end of the voltage comparator, and the comparison value of the voltage comparator is changed by adjusting the slide rheostat.
The AD acquisition module converts an analog signal into a digital signal for the MCU to read, and in order to realize high-precision conversion of the analog signal, an 8-channel bipolar 16-bit high-precision digital acquisition chip AD7606 is particularly used.
The probe includes electrode and data transmission cable two parts, and four copper electrodes of electrode part design A, B, M, N are located the data transmission cable bottom, and four electrodes respectively set up a wire and derive by the data transmission cable top, link to each other with signal acquisition module through the plug interface, and wherein AM 1.5m, MN 1m, NB 1.5m, can realize the data acquisition of multiple device forms such as dipolar, tripolar, quadrupole, natural potential, multiparameter, as shown in fig. 5. The total length of the cable is 50m, a cylindrical iron rod with the diameter of 8cm and the weight of 5kg is dropped at the bottom end, so that the probe can smoothly sink to the preset depth.
A second part: upper computer module
The rock-soil electrical prospecting instrument selects RaspberryPi as an upper computer, and the data acquisition device is connected with the upper computer through a UART. The graphical interface of the upper computer is displayed through the LCD touch screen, and a user can interact with the data acquisition device through the graphical interface of the upper computer, so that the data acquisition device is controlled, and meanwhile, the acquired data can be displayed through the graphical interface of the upper computer. USB expansion interface is used for realizing that the USB flash disk of measured data copies out, and the 4G module can make things convenient for the private cloud storage of measured data to realize the high in the clouds sharing of a large amount of measured data.
In order to facilitate the interaction between a user and a graphical interface of the upper computer, a 7-inch LCD capacitive touch screen is selected as a display screen of the upper computer, so that the humanized operation of the upper computer is realized.
In order to realize cloud storage of data, a 4G module is configured for an upper computer so as to facilitate data uploading. The system selects modules Hua' 909S-821.
The RaspberyPi and the MCU are communicated by adopting Serial, the RaspberyPi and the MCU are connected through an HDMI interface, and the 4G module is connected with the RaspberyPi through a USB adapter plate.
Claims (7)
1. The utility model provides an embedded digital intelligent drilling resistivity tester which characterized in that: the tester comprises an electrode power supply module, a signal acquisition module, an MCU module, an upper computer module and a probe;
the electrode power supply module selects a power supply with adjustable voltage and frequency; the system specifically comprises a lithium battery, a digital boosting module and an inversion module; the measurement of the resistivity and the ground resistance of the rock-soil body requires an external power supply to supply power to the rock-soil to be measured, an electrode power supply is supplied by a lithium battery, the digital adjustable boosting module is used for realizing the wide-range adjustment of voltage, and a direct-current power supply is converted into symmetrical square waves with adjustable frequency through an inversion module to supply power to the electrode;
the signal acquisition module is a signal acquisition circuit controlled by an MCU (microprogrammed control Unit), and is used for measuring current, voltage and phase difference values; the signal acquisition module specifically comprises a comparator, a current acquisition circuit, a voltage acquisition circuit and an AD conversion module; the acquisition of analog quantity is realized through a voltage and current acquisition circuit, and then an analog signal is converted into a digital signal by using an AD conversion module; when an alternating current power supply is used as a power supply, the difference of voltage and current phases can be caused by the capacitive reactance characteristics of rock and soil masses, so that the phase difference measurement is realized through hardware, a voltage comparator is connected behind a voltage and current acquisition circuit to convert an analog signal into a square wave signal, and then the phase difference measurement is realized by using MCU external interruption and a timer; the upper computer module is an interactive upper computer based on RaspberryPi; the user realizes the interaction with the MCU through the LCD touch screen; after the data measurement is finished, the data can be copied out by using a U disk, and the data can also be transmitted to a private cloud by using a 4G module;
the probe is arranged; the electrode comprises electrodes and a data transmission cable, wherein the electrodes are A, B, M, N four copper electrodes and are positioned at the bottom end of the data transmission cable, and the four electrodes are respectively provided with a lead which is led out from the top end of the data transmission cable and connected with a signal acquisition module through a plug-in interface.
2. The embedded digital intelligent borehole resistivity tester of claim 1, wherein: in order to avoid short circuit of the inverter after power-on, a switching circuit is added at the front end of the inverter module, and the MCU is used for controlling the on-off of the electrode power supply.
3. The embedded digital intelligent borehole resistivity tester of claim 1, wherein: the current acquisition circuit is realized by Hall current sensors, and three Hall current sensors with different measuring ranges are selected.
4. The embedded digital intelligent borehole resistivity tester of claim 3, wherein: the three measuring ranges are respectively 10mA, 1A and 15A.
5. The embedded digital intelligent borehole resistivity tester of claim 3, wherein: and the channel selection of the three measuring ranges is realized by adopting an electromagnetic relay.
6. The embedded digital intelligent borehole resistivity tester of claim 1, wherein: the voltage acquisition circuit is realized by adopting a voltage division method.
7. The embedded digital intelligent borehole resistivity tester of claim 1, wherein: the MCU module realizes communication with the AD conversion module through the SPI to carry out control of voltage and current measurement and data acquisition; the MCU captures the square wave signal output by the comparator module through external interruption to realize the measurement of the phase difference value; the MCU outputs two paths of inverse PWM waves to realize the control of the inversion module; and the UART and the upper computer graphical interface are used for realizing the transmission of configuration instructions and data.
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| CN113781599A (en) * | 2021-08-23 | 2021-12-10 | 上海市政工程设计研究总院（集团）有限公司 | Method and system for drawing drilling resistivity test result curve |
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Application publication date: 20191220 |