CN104900013A - Mud-rock flow monitoring and alarming system based on infrasonic wave - Google Patents

Abstract

The invention relates to a mud-rock flow monitoring and alarming system based on an infrasonic wave. The mud-rock flow monitoring and alarming system comprises an infrasonic sensor, a signal processing circuit, a data acquisition card and a computer. The infrasonic sensor is used for acquiring mud-rock flow infrasonic signals. The signal processing circuit is used for amplifying and filtering the mud-rock flow infrasonic signal. The signal acquisition card performs analog-to-digital conversion on the mud-rock flow infrasonic signal after signal processing and transmits the converted result to the computer. The computer utilizes an HHT method for performing time-frequency domain analysis on the signal and calculates out the power spectrum of the signal, thereby obtaining signal energy and furthermore determining a mud-rock flow disaster. The mud-rock flow monitoring and alarming system can perform real-time monitoring on occurrence of the mud-rock flow disaster and furthermore can perform alarming.

Description

A kind of based on infrasonic rubble flow monitoring and warning system

Technical field

The present invention relates to rubble flow monitoring technical field, particularly relate to a kind of based on infrasonic rubble flow monitoring and warning system.

Background technology

Rubble flow is the common geologic hazard in a kind of mountain area, in the area that mountain valley deep gully, landform are dangerously steep, soil property is soft by precipitation (comprising glacier, snow melting water, heavy rain etc.) and massif containing grit is formed after diluting, and is mingled with the special mighty torrent of a large amount of solid matter such as silt and stone in motion process.Rubble flow have break out suddenly, break with tremendous force, feature rapidly, and often with the multiple-disruption effect of landslide, flood and avalanche, destructive power is huge, and the security of the lives and property of the job facilities such as water conservancy and hydropower, mine, traffic of mountain area and the local masses in mountain area in serious threat.In recent years, there is macrosolifluction disaster continually all over the world, and caused thousands missing and die, cause huge infringement to the lives and properties of local resident.

At present mainly video surveillance is adopted to the monitoring means of rubble flow, or adopt artificial itinerant monitor system.This traditional monitoring mode, be not only difficult to ensure its efficiency and accuracy, and to occurring in the strategically located and difficult of access mountain area of landform, mode manually on duty lacks the personal safety guarantee of human observer.Therefore, study and design a kind of novel debris flow monitoring system, to making mud-stone flow disaster monitoring in advance, the loss that minimizing rubble flow causes has great significance.

Summary of the invention

Technical matters to be solved by this invention is to provide a kind of based on infrasonic rubble flow monitoring and warning system, carries out real-time monitoring to mud-stone flow disaster, and implements to report to the police.

The present inventor finds, when breeding mud-stone flow disaster or rubble flow occurs, lithosphere can because rupturing, rubbing and the phenomenon such as extruding and produce a kind of infrasound signals containing important geological information---infrasonic wave.Debris flow infrasound signal has frequency low (being about 0 ~ 20Hz), and wavelength is long, easily diffraction occurs, and runs into barrier and be difficult to characteristics such as being stopped in communication process.Debris flow infrasound signal is not easily absorbed in atmosphere, decay in communication process very little, far distance can be passed, and it has extremely strong penetration capacity, the high acoustical signal of frequency just can by it every living with a common ground paper, but to debris flow infrasound signal, common wall is also difficult to every living it.

The technical solution adopted for the present invention to solve the technical problems is: provide a kind of based on infrasonic rubble flow monitoring and warning system, comprise infrasound sensor, signal processing circuit, data collecting card and computing machine, described infrasound sensor is for gathering debris flow infrasound signal; Described signal processing circuit is used for carrying out amplification process and filtering process to the debris flow infrasound signal collected; Debris flow infrasound signal after signal transacting is carried out analog to digital conversion and is transferred in computing machine by the result after conversion by described data acquisition card; Described computing machine adopts HHT method to carry out Time-Frequency Analysis to signal, and calculates the power spectrum of signal, draws signal energy, and then carries out the judgement of mud-stone flow disaster.

When described computing machine carries out the judgement of mud-stone flow disaster, using the maximum spectrum energy value of ground unrest infrasonic sound segment signal as a reference energy, and determine a threshold value higher than this reference energy accordingly, when the infrasonic sound segment signal spectrum energy mxm. collected exceedes described threshold value, just once trigger, then energy is reset, calculate signal energy next time, judge again, by that analogy, calculate the triggering times in certain hour thus mud-stone flow disaster is judged, and judging whether to start warning system.

Described infrasound sensor is 4189 model sensors of B & K company.

Described data collecting card is NI9234 data collecting card.

Beneficial effect

Owing to have employed above-mentioned technical scheme, the present invention compared with prior art, there is following advantage and good effect: the present invention is directed to the infrasonic mechanism produced when mud-stone flow disaster occurs and conduct in-depth research, Hilbert-Hang conversion (HHT) is adopted to the infrasonic wave signal characteristic collected, it has good treatment and analysis effect to non-linear and non-stationary signal, and the infrasonic wave that rubble flow can be produced and ground unrest carry out effective separation.The debris flow infrasound signal that infrasonic sensor collects by the present invention, be converted to digital signal through data collecting card and send into computing machine, use the digital signal processing method such as MATLAB software and HHT, feature according to infrasonic wave signal carries out process and the analysis of data, the final threshold value according to setting, real-time monitoring is carried out to mud-stone flow disaster, and implements to report to the police.

Accompanying drawing explanation

Fig. 1 is overall system block diagram of the present invention;

Fig. 2 is background noise spectrum figure;

The signal spectrum figure that Fig. 3 collects when being concrete mixer work;

Fig. 4 is the signal waveforms of data acquisition module display;

Fig. 5 is that HHT converts later infrasound signals time-frequency figure;

Fig. 6 is disaster decision flowchart;

Fig. 7 is Background Noise Power spectrogram;

Fig. 8 is the signal power spectrogram collected in experiment.

Embodiment

Below in conjunction with specific embodiment, set forth the present invention further.Should be understood that these embodiments are only not used in for illustration of the present invention to limit the scope of the invention.In addition should be understood that those skilled in the art can make various changes or modifications the present invention, and these equivalent form of values fall within the application's appended claims limited range equally after the content of having read the present invention's instruction.

Embodiments of the present invention relate to a kind of based on infrasonic rubble flow monitoring and warning system, and as shown in Figure 1, comprise infrasound sensor, signal processing circuit, data collecting card and computing machine, described infrasound sensor is for gathering debris flow infrasound signal; Described signal processing circuit is used for carrying out amplification process and filtering process to the debris flow infrasound signal collected; Debris flow infrasound signal after signal transacting is carried out analog to digital conversion and is transferred in computing machine by the result after conversion by described data acquisition card; Described computing machine adopts HHT method to carry out Time-Frequency Analysis to signal, and calculates the power spectrum of signal, draws signal energy, and then carries out the judgement of mud-stone flow disaster.

The infrasound sensor of system front end adopts 4189 model sensors of B & K company, the debris flow infrasound signal collected carries out enlarge leadingly and filtering process, then after the AD conversion and Bian sample of NI9234 data collecting card, enter meter grate machine.For the feature of debris flow infrasound signal, the software systems of the signal Bian collection of computer based under MATLAB platform, process and analysis, in conjunction with Digital Signal Processings such as advanced HHT conversion, complete the process of debris flow infrasound signal, waveform display and signature analysis, finally realize monitoring and the warning of mud-stone flow disaster.

The HHT that the present invention adopts is a kind of new signal processing method, and its object carries out Hilbert conversion to make signal be more suitable for.It is primarily of two part compositions, one is empirical mode decomposition (Empirical Mode Decomposition, EMD), also be topmost part, the core concept of this part is intrinsic mode function (Intrinsic Mode Function, IMF), arbitrary signal can obtain through empirical mode decomposition the intrinsic mode function that limited can be carried out Hilbert conversion; Two is Hilbert analysis of spectrums.Signal converts through Hilbert, can obtain the attribute informations such as instantaneous amplitude, instantaneous phase, instantaneous frequency, and then obtains Hilbert marginal spectrum.

HHT conversion reflects the time-frequency characteristics of signal exactly, fully aware ofly can identify the frequency discontinuity position of signal in moment point, accurately differentiates major frequency components and there is not cross term, having good time-frequency locality in addition.Time-Frequency Analysis Method in the past will be subject to the restriction of Heisenberg uncertainty principle, its temporal resolution and frequency resolution are inconsistent, but this phenomenon does not exist in Hibert-Huang conversion, then Hilbert spectrum is directly obtained by the instantaneous frequency and instantaneous amplitude that calculate IMF component processed, and its time and frequency resolution are separate.

The present invention is further illustrated below with a specific embodiment.

Mud-stone flow disaster has sporadic and very large danger, so directly Bian collection debris flow infrasound signal is very difficult.Therefore, after debris flow infrasound signal characteristic having been done to analysis and research, the experiment of inventor's design simulation debris flow infrasound signal, the infrasound signals of the feature similarity of the infrasound signals produced when Bian collection and mud-stone flow disaster occur.Find after research, the place that concrete mixer work or conveyor carry out the operation of falling sandy soil also can produce the infrasound signals with the feature similarity of debris flow infrasound signal.Accordingly, a place is selected to have the building site of concrete-agitating machine operation as the place gathering infrasound signals.

Test the infrasound signals data in Bian collection two kinds of situations, a kind of situation is a Bian collection ground unrest, and the second situation is that ground unrest and infrasound signals all exist.In two kinds of situations experimental apparatus arrange identical, once sampled every 1 second, Bian sample set of time is 2 minutes, and Bian sample frequency is 22.5KHz, is below the record case of experimental data:

(1) ground unrest

Ground unrest is the environmental sound signal collected when concrete mixer not operation, and the signal spectrum figure now collected as shown in Figure 2.The horizontal ordinate of Fig. 2 is frequency, and unit is Hz, and ordinate is power, and unit is dB, can find out that energy in the frequency range of below 20Hz is greatly between-20dB and-10dB from spectrogram.

(2) sound signal during work of Bian collection concrete mixer

Do not change the setting of experimental apparatus, gather sound signal when concrete mixer normally carries out operation, Figure 3 shows that the voice data that in concrete mixer course of normal operation, Bian collection arrives.As can be seen from Figure 3, during concrete mixer work, the signal energy of the following Infrasonic Frequencies of 20Hz creates change, and especially 16Hz there occurs larger change with the signal energy in lower frequency range.And the substantially not large change of the energy of more than 20Hz and high band part, its reason is, there is various noise in the environment around during image data, as vehicle and personnel move.Therefore the energy being greater than listened to the frequency range part of 20Hz remains certain state, does not significantly change.

In Bian collection signal process, can find concrete mixer when operation and not operation Bian collection to signal have significant change.Concrete mixer is not when carrying out operation, and collect the infrasonic sound section energy of signal greatly between-10dB to-20dB, infrasonic sound section is roughly about-20dB with the signal energy of super band.After concrete mixer starts operation, Bian collection to signal infrasonic sound section energy be then changed to more than-10dB, 2 ~ 8Hz frequency band signals energy reaches 10dB especially.But now undersonic frequency still maintains about-20dB with the signal energy of super band.Therefore, can show that the energy Ratios ground unrest infrasonic sound section energy of signal infrasonic sound section has by experiment to increase more significantly, namely on the energy intensity of Infrasonic Frequencies, rubble flow signal is significantly improved than ground unrest, thus rubble flow signal can be separated with ground unrest.

In experiment Bian collection to sound signal import in system and process.In time domain, these signal waveforms are all rambling non-stationary signals, cannot directly analyze, and what need to pay close attention to is infrasound signals lower than 20Hz, and the data that Bian collection is come in are on full bandwidth, therefore need to carry out a series of process to it, comprise and the process such as low-pass filtering, noise reduction is carried out to signal.Be illustrated in figure 4 data Bian collection module and show the waveform collected.

After the infrasound signals wave data processing of Bian collection, Time-Frequency Analysis is carried out to it, Bian HHT method, as shown in Figure 5.From found that, can be able to find out not in the same time from the time-frequency domain figure of HHT, frequency component existing in signal, and the energy distribution of signal also can be changed by the color of time-frequency figure, be i.e. embody in the change of signal intensity.Thus the change of infrasound signals frequency content can well be understood, reflect the Voice segment situation of each frequency, research rubble flow signal tool is had very important significance.

Through a series of signal process, as the process such as low-pass filtering, noise reduction, re-use after HHT analytical approach analyzes signal, finally calculate the power spectrum of signal, draw signal energy, and then can disaster judgement be carried out.Will carry out fft analysis and energy monitoring to debris flow infrasound signal, take energy as the generation of standard determination mud-stone flow disaster.In order to easy analysis simplifies calculating simultaneously, therefore the problem in time domain is converted in frequency domain and processes, with Fourier series expression be:

$x\left(t\right)={\mathrm{\α}}_0+\underset{n=1}{\overset{\mathrm{\∞}}{\Σ}}({\mathrm{\α}}_{n}cos2\mathrm{\π}nft+\mathrm{\β}sin2\mathrm{\π}nft)---\left(1\right)$

Wherein, α ₀for constant term, α _nbe Fourier coefficient with β, n is harmonic number.

Fourier transform is carried out to above formula:

$x\left(f\right)={\∫}_{-\mathrm{\∞}}^{\mathrm{\∞}}x\left(t\right)\exp (-j2\mathrm{\π}ft)dt---\left(2\right)$

Next time domain waveform is become frequency spectrum function:

$F\left(j\mathrm{\ω}\right)=FFT\[f\left(t\right)\]={\∫}_{-\mathrm{\∞}}^{\mathrm{\∞}}f\left(t\right)e^{-j\mathrm{\ω}t}dt---\left(3\right)$

Wherein, ω is angular frequency, and f (t) is periodic function.

Energy signal is defined as the energy of fixed time (0 ,-∞) upper signal, represents with letter e:

$E={\∫}_{-\mathrm{\∞}}^{\mathrm{\∞}}{f}^2\left(t\right)dt---\left(4\right)$

Represent ENERGY E with frequency spectrum function F (jw), then can obtain:

$E={\∫}_{-\mathrm{\∞}}^{\mathrm{\∞}}{f}^2\left(t\right)dt={\∫}_{-\mathrm{\∞}}^{\mathrm{\∞}}f\left(t\right)\[\frac{1}{2\mathrm{\π}}{\∫}_{-\mathrm{\∞}}^{\mathrm{\∞}}F\left(j\mathrm{\ω}\right)e^{j\mathrm{\ω}}d\mathrm{\ω}\]dt---\left(5\right)$

Exchange integral order can obtain:

$E={\∫}_{-\mathrm{\∞}}^{\mathrm{\∞}}{f}^2\left(t\right)dt=\frac{1}{2\mathrm{\π}}{{\∫}_{-\mathrm{\∞}}^{\mathrm{\∞}}\left|F\left(jw\right)\right|}^{2}d\mathrm{\ω}---\left(6\right)$

Based on above-mentioned theory, designing a threshold value and trigger with MATLAB, by triggering, extracting the fragment in signal.By the analysis of voice data of arriving Bian collection and research, a decision algorithm can be designed.Using the maximum spectrum energy value of ground unrest infrasonic sound segment signal as a reference energy, determine a threshold value higher than this energy accordingly, when the infrasonic sound segment signal spectrum energy mxm. collected exceedes this threshold value, just once trigger.Then reset energy, calculate signal energy next time, then carry out the step such as judging, by that analogy, calculate the triggering times in certain hour, judge whether to start warning system.This section judges that the time of triggering times needs to arrange just right, unsuitable long, also unsuitable too short.The time too short situation that there will be wrong report, if set of time is oversize, has the danger of failing to report.Disaster decision flowchart as shown in Figure 6.

Concrete steps are: the background noise data collected experimentally, and energy threshold is set as-5dB, and the condition given the alarm is set as that 2 seconds internal trigger number of times reach 4 times.If namely monitoring modular reaches more than 4 times at 2 seconds internal trigger number of times, just send disaster alert.Fig. 7 is Background Noise Power spectrum, and Fig. 8 is the power spectrum signal collected in experiment.

As can be seen from Figure 7, at ground unrest 20Hz with in lower frequency range, highest energy value is about-10dB, does not exceed the threshold value of-5dB, does not trigger.But Fig. 8 display, highest energy value is at about 8dB, and in the signal Infrasonic Frequencies namely collected, highest energy value is greater than the energy threshold of-5dB, meets trigger condition, once triggers.

When there is mud-stone flow disaster, the conversion that research rubble flow signal causes in time, first the power spectrum of rubble flow signal is obtained, then the energy variation of each frequency component of analytic signal, in disaster generating process, the power spectral energies of rubble flow signal infrasonic sound section is compared will have significant increase with ground unrest infrasonic sound section energy, and namely on energy intensity, rubble flow signal significantly improves than ground unrest, thus rubble flow signal can be separated with ground unrest infrasonic sound section.Finally, by the energy value of Monitoring Debris Flow infrasound signals in setting-up time, whether exceed energy threshold, and the number of times exceeding threshold value reaches more than setting value, then carry out disaster judgement and report to the police.

Claims (4)

1., based on infrasonic rubble flow monitoring and a warning system, comprise infrasound sensor, signal processing circuit, data collecting card and computing machine, it is characterized in that, described infrasound sensor is for gathering debris flow infrasound signal; Described signal processing circuit is used for carrying out amplification process and filtering process to the debris flow infrasound signal collected; Debris flow infrasound signal after signal transacting is carried out analog to digital conversion and is transferred in computing machine by the result after conversion by described data acquisition card; Described computing machine adopts HHT method to carry out Time-Frequency Analysis to signal, and calculates the power spectrum of signal, draws signal energy, and then carries out the judgement of mud-stone flow disaster.

2. according to claim 1 based on infrasonic rubble flow monitoring and warning system, it is characterized in that, when described computing machine carries out the judgement of mud-stone flow disaster, using the maximum spectrum energy value of ground unrest infrasonic sound segment signal as a reference energy, and determine a threshold value higher than this reference energy accordingly, when the infrasonic sound segment signal spectrum energy mxm. collected exceedes described threshold value, just once trigger, then energy is reset, calculate signal energy next time, judge again, by that analogy, calculate the triggering times in certain hour thus mud-stone flow disaster is judged, and judge whether to start warning system.

3. according to claim 1 based on infrasonic rubble flow monitoring and warning system, it is characterized in that, described infrasound sensor is 4189 model sensors of B & K company.

4. according to claim 1 based on infrasonic rubble flow monitoring and warning system, it is characterized in that, described data collecting card is NI9234 data collecting card.