SU714327A1 - Method of measuring physical properties of rock mass - Google Patents

Description

I

The invention relates to methods for measuring (and counterpropane) physical

rock mass properties, in particular, strength and electrical parameters of rocks (conductivity, dielectric and magnetic permeability, compression iodules, shear expansion, etc.) by low-frequency geophysical methods in the process of managing rtq) H6 mining operations and can be used geophysical measurements and investigations of low-frequency electromagnetic and acoustic fields in the presence of industrial interference in high intensities, as well as in other areas of the national economy: in the power supply when searching for underground cables, in the oil and gas industry to search for underground pipelines.

It is known that for indirectly squaring and controlling physical properties. solid rock are applied based on methods. geophysical methods. In most used

By means of an alternating current generator, electromagnetic or acoustic oscillations are excited in an array and measured at the site of a diet, the amplitude or phase of voiced disturbances) passed through the rock massif. The known ratios that relate the measured amplitude and phase characteristics of the signals to the rock parameters determine and control the physical properties of the array, and the accuracy and reliability of the desired parameters depend on the accuracy and reliability of the measurement of received signals.

A known system for solving geoelectromagnetic problems with the use of synchronous generators and non-transducer means combined; uni ij.

An alternating current excites in the ground an electrical field electrically controlled oairoii frequency and measured sweat at the receiving site of 4-way az) x-actor actuation of the excited oscillations by the receiving device. Frequency

The signal of a prime mixer is taken equal to the frequency of the alternator current.

It is also known a device for measuring the changes in periodic signals from noise in a system caused by a laser, where a generator of periodic signals is excited in a medium by electromagnetic oscillations of a single frequency and the amplitude-phase characteristics of excited vibrations by a receiving device, in which the frequency of the reference signal of the receiver mixer is selected, where the frequency of the reference signal of the receiver mixer is selected in which the frequency of the reference signal of the receiver, in which the frequency of the reference signal of the receiver mixer is chosen, the frequency of the reference signal of the receiver, selected in which the frequency of the reference signal of the receiver is chosen. alternator current 2.

The disadvantage of these devices is tu | WHETHER THEM THE FREQUENCY CHANGE 1X) OF THE GENERATOR CURRENT AND SUPPORT VIBRATIONS

 receiver bodies stabilize to

resonator (clock), and, consequently, the receiver's bandwidth is rigidly fixed to the frequency axes. In this case, industrial interference from working machines and mechanisms has its own unstable 610, 1 2 receiver bandwidth, which distorts the measurement results and causes to an incorrect assessment of the state of waccw va. . -. :. H. ; .

The closest is the method of measuring the electromagnetic parameters of the SchrSch of the solar signals, in which the alternating current generator excites two electromagnetic oscillations in the array;

over the entire modulation period. At the reception site, the change in the difference of the difference values is measured during the modulation period, according to which the electrical pairs of rocks under investigation are judged, by the receiving device, in which the frequency of the reference signal of the receiver’s receiver is equal to the difference between the frequency and frequency, which is excitable in masses ZZ alternator

The disadvantage of this method is that frequency modulated oscillations are excited in the array; Therefore, a pair of WeTpOB signals is measured with a wide bandwidth receiver. Under the conditions of mining operations in the strip - the Pr5NK1SSh "W 11r% ŠШSH11S get signals ° С1ШЙ5ФЮГЕШХ Ш Шг1Йо1Ц1йНН Шь1Иннт ІцТOРІХ often np iibifflfaefyyyyyyyyyyi Interpretation of measurement results

tipffii iSk eignals of the state of the rock mass in this case;

714327

It becomes difficult and leads to erroneous results.

The objective of the proposed life is the elimination of the influence of industrial interference from working machines and mechanisms on the measured characteristics of the received oscillations.

To do this, using industrial noise, the presence of which at the place of excitation and reception of oscillations is considered as a positive factor, filter the signals of the spectral components of the noise, divide the frequencies of the silent components by their doubled order number and multiply an odd number of times; the received signals excite electromagnetic or acoustic oscillations in the rock massif, and also use them as reference signals, and judging by the results of measurements, the physical properties of the rock massif. . .

In this method, an alternating current generator excites acoustic or electromagnetic low-frequency oscillations in an array, depending on the method used, and the work is carried out at one or several frequencies. The receiver measures, at the point of reception, the informative characteristics of the vibrations that have passed through the array amplitude, phase (delay time), or both. The frequency of the reference signal of the receiver mixer is chosen equal to the generator frequency. According to the values of the measured characteristics, the density and electrical parameters of rocks are determined, and by their change, the state of the array is monitored.

The essential difference between the proposed method and the known method is that the alternating current frequency of the generator and the operative oscillations of the receiver's mixer are formed from the signals of the spectral components of the industrial noise present at the place of excitation and reception of acoustic or electromagnetic oscillations. Due to this, receive a synchronous change in the frequency of the generator and the reference oscillations of the mixer of the receiver with a change in the frequency of interference.

Claims (3)

In the known methods, the frequency of the alternating current of the generator and the reference signal of the mixer of the receiver is formed by local generators, the fixed frequency of which the variable frequency is not related to the frequency of interference. In the proposed method, the frequency rc hepaTopa and the reference oscillations of the receiver blender are formed from a discrete spectrum of industrial interference, for which the spectral component, for example, 50 Hz, is separated from the spectrum, the frequency of the selected component is divided by its double number and multiplied into an odd number of . By such a conversion, the operating frequency of the generator and the frequency of tuning the receiver are located between the spectral components of the interference and any instability of the latter, and thereby exclude the influence of the spectral components of the interference on the measured characteristics of the received oscillations. In the proposed method, the interference is specifically passed into the generator and, by the way, the operating frequencies are formed from them, while in the known methods the interference is suppressed at the receiver input or during signal processing. Figure 1 shows the spectra of interference and operating signals explaining the proposed invention. FIG. 1a shows the spectral components of industrial noise; in fig. 16 the movement of interference along the frequency axis of the eigenfrequency frequency instability HOctHj in FIG. 1 c. The procedure for generating the operating frequency of the generator and receiver from industrial plots is shown in FIG. 1g. Spectrums of interference and working signal upon reaching sang. Fig 2 shows a block diagram of a device for implementing the proposed method. The device contains electrodes 1, immersed in an array for receiving the noise signal, band-pass filters 2 for the generator and receiver, amplifier 3, dividers 4 for the interference frequency, multipliers 5 for the interference frequency; bandpass filters 6 of the generated operating frequencies of the generator and receiver, amplifier 7 of the generator power, electrode generator 8 of the receiver for exciting and receiving electrical oscillations, amplifiers 9, receiver bandpass filter 10 tuned to the received oscillations, receiver offset 11, arrow 12 the indicator, the automatic gain control unit 13, the local generators 14 in the generator and the receiver, the keys 15 enable local heaters. Dryness of the proposed method is explained as follows. In the rock mass, a field is excited by an generator of recogenic current, which is located in the mine workings at a distance from shchemnik. From the discrete spectrum of industrial noise existing in the array, the spectral component is selectively selected, preferably of high intensity, for example) c (Fig. 1a). forming the working frequency of the generator and the frequency of the reference oscillations equal to it, the preectics mixer, the selected component of the interference, is divided by its double number and multiplied an odd number of times. Thus, in the generator and the receiver, over the frequency of the selected spectral component of the interference f, an operation is performed; fp%: C2MH}, is the operating frequency of generator 1) a and the reference oscillations of the receiver’s cMectfel; k is the sequence number of the noise component of the interference component; K 1, 2, ...; , And - any integer, 0, .. The numbers of Kii are chosen so that the working frequency of the generator takes the knowledge necessary for this method to control the rock mass. With this re-formation, the operating frequency of the generator and the opsf oscillations of the receiver's mixer are located strictly between the spectral components of the interference (Fig. 1c). If the interference has frequency instability i l $ q (Fig. 1b), then the operating frequency is also unstable and may not change in the range; where 1 & p is the absolute instability of the operating frequency, while remaining all the csms between the spectral components of the interference (Fig. 1d). As a result, the spectral components of the interference f k are eliminated. P any frequency oscillations. ± A i, in the receiver bandwidth, tuned to the frequency p, and excludes the influence of interference and the amplitude-phase characteristics of the measured signal. In the known methods, interference due to intrinsic instability falls into the receiver passband tuned 77 to constant nacixn-y (Fig. 1C). When working with the frequency-frequency methods, the tests and contacts (x) l are in accordance with ph}. Mula (1) form a network of discrete working frequencies p-, p, and so on. The device side for the implementation of the cut-off is shown in FIG. 2. Interference is induced on the electrodes 1, the voltage that the filter 2 has with the passband where the component vt f is extracted is amplified by the amplifier 3, divided by the doubled row number by the divisor 4, multiplied an odd number of times the multiplier 5 and serves n 1 olos filter 6 with a bandwidth $ p i p. The frequencies obtained by the yulebany “ycvj” are fed with power 7 by the slinginggel and excite an array through the electrodes 8. The cells that pass through the medium induce the same useful frequency signal p on the electrodes 8 of the Hanps receiving device that are amplified by amplifiers 9 and before and after filtering it with a volume of 1 o by the band p t Ck 5.p and are fed along with the suppressed filter by the Y components to the mixer 11. Mixture The aggregates of the useful signal ymehme each yot that signal whose frequency is equal to the frequency of the reference oscillations — the useful signal of the frequency p is located d between aged clutter. The voltage of the BF signal is maintained by a constant AGC unit 13. The signal at the mixer output is measured by the device 12. If the interference intensity is low, the local generators 14 operating frequencies ip are connected to the generator and the receiver using switches 15. electrodes 1; They also use an electric or magnetic antenna, a seismic receiver, and a low-voltage transformer of the mains voltage, due to the formation of a transmission frequency ftHotx TtbKa - a generator:) a and the reference oscillations of the sjmiemlik mixer from pro-interference and the location of the operating frequency between the spectral components. interference eliminate the influence of the latter on the characteristics of the measured 7 signal and, consequently, on the accuracy and reliability of the parameters of rocks. The proposed method, with a comparatively small hardware complication, allows measuring and controlling the physical properties of an array of rocks during mining operations in the presence of High-intensity interference from working machines and mechanisms, which makes it possible to continuously and monitor the state of the array, control technical processes of mining, to ensure safe working conditions. The invention The method of measuring the physical properties of an array of rocks is based; 1st on the excitation in the array of electromagnetic or acoustic oscillations of one or several frequencies, the formation of a reference signal whose frequency is equal to the frequency of the excited oscillations, measured at the reception point of the amplitude-phase characteristics of the excited oscillations, different the fact that, in order to eliminate the effect of industrial interference on the measurement results, the signals of the spectral components of the interference are filtered, the frequencies of these components are divided twice their sequence number and multiply in an odd number of times, the received signals excited in the rock mass, electromagnetic or acoustic vibrations, as well as their use as opsfnyh signals and the results of measurements L judged on the physical properties of the rock mass. Sources of information taken into account in the examination 1. US patent number 3701940, cl. 324-i, pubic. 1975. 2. US patent number 3984759, cl. 324-6, published. 1976. 3. USSR author's certificate number 492836, cl. Q 01 V 3/12, 1975 (prototype).