CN112904409A - Device and method for measuring deposition characteristics of underwater sediments based on distributed acoustic sensing technology - Google Patents
Device and method for measuring deposition characteristics of underwater sediments based on distributed acoustic sensing technology Download PDFInfo
- Publication number
- CN112904409A CN112904409A CN202110068569.1A CN202110068569A CN112904409A CN 112904409 A CN112904409 A CN 112904409A CN 202110068569 A CN202110068569 A CN 202110068569A CN 112904409 A CN112904409 A CN 112904409A
- Authority
- CN
- China
- Prior art keywords
- sensing element
- sensing
- underwater
- optical fiber
- strain
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000013049 sediment Substances 0.000 title claims abstract description 104
- 238000000034 method Methods 0.000 title claims abstract description 28
- 230000008021 deposition Effects 0.000 title claims abstract description 20
- 239000013307 optical fiber Substances 0.000 claims abstract description 73
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 52
- 230000008054 signal transmission Effects 0.000 claims abstract description 7
- 238000012360 testing method Methods 0.000 claims description 19
- 238000005259 measurement Methods 0.000 claims description 16
- 238000012545 processing Methods 0.000 claims description 12
- 239000000835 fiber Substances 0.000 claims description 11
- 238000001914 filtration Methods 0.000 claims description 9
- 239000003550 marker Substances 0.000 claims description 9
- 230000005284 excitation Effects 0.000 claims description 8
- 238000003780 insertion Methods 0.000 claims description 8
- 230000037431 insertion Effects 0.000 claims description 8
- 238000000691 measurement method Methods 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 6
- 230000008859 change Effects 0.000 claims description 5
- 238000012544 monitoring process Methods 0.000 claims description 5
- 238000009991 scouring Methods 0.000 claims description 5
- 230000007774 longterm Effects 0.000 claims description 4
- 238000012800 visualization Methods 0.000 claims description 4
- 238000001514 detection method Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 230000000149 penetrating effect Effects 0.000 description 5
- 239000003822 epoxy resin Substances 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 229920000647 polyepoxide Polymers 0.000 description 3
- 238000005070 sampling Methods 0.000 description 3
- 230000000007 visual effect Effects 0.000 description 3
- 230000005672 electromagnetic field Effects 0.000 description 2
- 230000004927 fusion Effects 0.000 description 2
- 239000004576 sand Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/16—Receiving elements for seismic signals; Arrangements or adaptations of receiving elements
- G01V1/18—Receiving elements, e.g. seismometer, geophone or torque detectors, for localised single point measurements
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
- G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/28—Processing seismic data, e.g. for interpretation or for event detection
- G01V1/30—Analysis
- G01V1/306—Analysis for determining physical properties of the subsurface, e.g. impedance, porosity or attenuation profiles
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/28—Processing seismic data, e.g. for interpretation or for event detection
- G01V1/30—Analysis
- G01V1/307—Analysis for determining seismic attributes, e.g. amplitude, instantaneous phase or frequency, reflection strength or polarity
Landscapes
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geophysics (AREA)
- Testing Or Calibration Of Command Recording Devices (AREA)
Abstract
The invention discloses a device and a method for measuring deposition characteristics of underwater sediments based on a distributed acoustic wave sensing technology, wherein a sensing element in the measuring device of the method consists of a sighting rod and a strain sensing optical fiber; the strain sensing optical fiber is fixed in the groove of the mark post; the optical fiber lead is connected with the strain sensing optical fiber; the pulse vibrator is fixed on the top of the sensing element; one end of the distributed acoustic sensing demodulator is connected with the computer through a signal transmission line, and the other end of the distributed acoustic sensing demodulator is connected with the sensing element through an optical fiber lead; the sensing element is vertically inserted into a certain underwater position to be measured, then a signal emitter is used for emitting signals to the pulse vibrator at the bank side, the pulse vibrator generates pulse vibration after receiving the signals, the strain and frequency characteristics of the sensing element during vibration are analyzed, the position of the underwater sediment-water interface is judged according to the strain characteristics of the sensing element, and the type of the underwater sediment is judged according to the frequency characteristics of the sensing element.
Description
Technical Field
The invention relates to the field of underwater sediment deposition characteristic measurement, in particular to an underwater sediment deposition characteristic measurement device and method based on a distributed acoustic wave sensing technology
Background
Underwater sediments are mainly solid substances that enter the water body in various ways and finally settle on the bottom of the water body under the action of gravity. At different positions, the types of the underwater sediments and the positions of the interfaces of the underwater sediments and the water body have obvious difference. The research on the deposition characteristics of underwater sediments plays an important role in researching river and sea hydrology and environmental evolution. Due to the natural blockage of the water body, the type of underwater sediments and the position of the interface with the water body cannot be known through visual observation. The existing methods for detecting the characteristics of underwater sediments mainly comprise several methods: ground penetrating radar measurement, sampler sampling and fiber grating measurement. In principle, due to the fact that dielectric constants of different media are different, reflection signals of electromagnetic waves received by the ground penetrating radar are different, and underwater structure information is obtained by analyzing frequency spectrum characteristics of the electromagnetic waves received by the ground penetrating radar; however, because the detection means is electromagnetic wave detection, the device is easily interfered by external electromagnetic field in the measurement process, thereby causing influence on the measurement result, and when the dielectric coefficients of the underwater medium are not large, the ground penetrating radar is difficult to distinguish the underwater medium. The sampler sampling method is characterized in that researchers use a sampler to collect samples at various positions and analyze and obtain the granularity characteristics and the lithology characteristics of sediments at different underwater positions. In recent years, an emerging fiber grating measurement method is to analyze strain data of fiber gratings at various positions on a sensing element so as to judge the positions of underwater deposits and water interfaces. However, this measurement method requires a large number of fiber gratings to be disposed on the sensing element, which is costly to measure, and the fiber gratings are easily damaged in water during the detection process, and the damaged fiber gratings need to be inspected and replaced in time.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a device and a method for measuring the deposition characteristics of underwater sediments based on a distributed acoustic wave sensing technology, which detect the type of the underwater sediments through a sensing optical fiber and determine the interface position of the underwater sediments and water.
The invention adopts the following technical scheme: an underwater sediment deposition characteristic measuring device based on a distributed acoustic wave sensing technology comprises a sensing element, a distributed acoustic wave sensing demodulator, an optical fiber lead, a computer, a signal emitter and a pulse vibrator; one end of the distributed acoustic wave sensing demodulator is connected with the computer through a signal transmission line, and the other end of the distributed acoustic wave sensing demodulator is connected with the sensing element through an optical fiber lead; the pulse vibrator is fixed on the top of the sensing element; the sensing element consists of a post and a strain sensing optical fiber, and the strain sensing optical fiber is embedded in the post.
The marker post is a slender rod with a circular section, the surface of the marker post is provided with a groove, the direction of the groove is parallel to the axial direction of the marker post, and the strain sensing optical fiber is fixed in the groove; the fiber optic pigtail is connected to a strain sensing fiber in the sensing element.
The pulse vibrator comprises three modules: the device comprises a signal receiving module, a pulse vibration module and a power supply module; the three modules are electrically connected, the power supply module is responsible for supplying power to other modules, and when the signal receiving module receives a transmitting signal transmitted by the signal transmitter, the pulse vibration module immediately generates pulse vibration to enable the sensing element to vibrate.
The measuring method of the underwater sediment deposition characteristic measuring device based on the distributed acoustic sensing technology comprises the following steps:
firstly, carrying out a calibration test on a measuring device indoors to obtain an empirical relation curve of the vibration frequency of a sensing element and the type of underwater sediments;
vertically inserting a sensing element in the measuring device into a certain underwater position to be measured, after the device is stabilized, transmitting an excitation signal to a pulse vibrator by using a signal transmitter on the bank, and acquiring and recording strain data of the sensing element during vibration by using a distributed acoustic wave sensing demodulator;
thirdly, extracting data recorded by the distributed acoustic wave sensing demodulator in the second step by using computer software, arranging the recorded strain data according to the sequence from the top to the bottom of the sensing element, and analyzing the strain data of each position so as to determine the interface position of the underwater sediment and the water;
fourthly, performing fast Fourier transform on the recorded strain data, extracting frequency data of the vibration of the sensing element, and judging the type of underwater sediment according to the measured vibration frequency according to an empirical relation curve of the vibration frequency of the sensing element and the type of the underwater sediment;
and step five, transmitting signals at the water bank side by using a signal transmitter at regular intervals, repeating the step three and the step four, measuring the position of the underwater sediment-water interface and the type of the sediment at the position of the sensing element, comparing the position with the previous measurement result, obtaining the lifting condition of the position of the underwater sediment-water interface and the change condition of the type of the sediment, further realizing long-term monitoring of the scouring or siltation of the seabed, the river bed and the lake bed, and judging the type and the thickness of the scoured or silted sediment.
In the first step, the position of the sensing element corresponding to each optical fiber record is determined through a calibration test, the track number of each optical fiber and the position of the corresponding sensing element are recorded, and position reference is provided for later analysis of strain data of the optical fiber.
The method comprises the steps of obtaining an empirical relationship between the vibration frequency of a sensing element and the type of underwater sediments through an indoor calibration test, continuously changing the type of the underwater sediments and the insertion depth of the sensing element for the same sensing element, vibrating the sensing element by using a pulse vibrator to obtain frequency data of vibration of a plurality of sensing elements, and then carrying out visualization processing on the frequency data to obtain an empirical relationship curve between the vibration frequency of the sensing element and the type of the underwater sediments.
And in the third step, when the sensing element vibrates, the strain of the sensing element is maximum near the interface position of the sediment and the water, the strain data of each position of the sensing element is compared, the optical fiber channel number with the maximum strain is recorded, and the position of the sensing element corresponding to the channel is the interface position of the underwater sediment and the water.
In the fourth step, in order to reduce the interference of the external environment noise on the frequency measurement, the data is denoised firstly, and the denoising process comprises the following steps: firstly, main frequency analysis is carried out on each optical fiber data, then, filtering processing is carried out on the optical fiber data according to the main frequency analysis result, and finally, the optical fiber data after each channel of filtering is overlapped, so that the signal-to-noise ratio is improved.
And step four, substituting the measured vibration frequency into the empirical relation curve to judge the type of the sediment in the water.
The invention has the beneficial effects that:
(1) the underwater sediment-lake water interface position can be quickly and effectively determined, and the type of underwater sediment can be judged;
(2) the distributed acoustic wave sensing technology has the advantages of high sensitivity, corrosion resistance and strong electromagnetic interference resistance, and can meet the application requirements of complex and severe scenes;
(3) compared with a ground penetrating radar measuring method, the distributed acoustic sensing technology is utilized to detect underwater sediments, so that the interference of an external electromagnetic field can be effectively resisted, and the detection is not influenced by the dielectric constant of an underwater medium; compared with a sampler sampling method, the underwater sediment detection by using the distributed acoustic sensing technology can greatly improve the detection efficiency, and the underwater sediment detection by using the distributed acoustic sensing technology can not only detect the type of the underwater sediment, but also determine the interface position of the underwater sediment and water; compared with a fiber grating measurement method, the method for detecting the underwater sediments by using the distributed acoustic sensing technology can determine the interface position of the underwater sediments and water, can detect the type of the underwater sediments, and does not need to arrange a large number of sensing elements for detection. The method is simple to operate and rapid in measurement, the underwater sediment-water interface position can be obtained only by one optical fiber, the type of the underwater sediment can be detected, the measurement cost is greatly reduced, and the method is convenient for field workers to use;
(4) the method can be used for monitoring the scouring and silting of the seabed, river bed or lake bed for a long time and judging the type and thickness of the scoured or silted sediment.
Drawings
FIG. 1 is a schematic structural diagram of a measuring device according to the present invention;
FIG. 2 is a schematic diagram of an indoor calibration experiment according to the present invention;
FIG. 3 is a simplified schematic of the underwater deposit of the present invention;
FIG. 4 is an empirical relationship of the vibration frequency of the sensing element and the type of underwater deposits in example 1 of the present invention;
FIG. 5 shows the vibration frequency f of the sensor element in embodiment 1 of the present invention1A map of empirical relationships;
FIG. 6 shows the vibration frequency f of the sensor element in embodiment 1 of the present invention2A map of empirical relationships;
in the figure: 1 is a sensing element, 1-1 is a mark post, 1-2 is a strain sensing optical fiber, 2 is a distributed acoustic wave sensing demodulator, 3 is a computer, 4 is a signal transmitter, 5 is a pulse vibrator, 5-1 is a signal receiving module, 5-2 is a pulse vibration module, 5-3 is a power supply module, 6 is an optical fiber lead, 7 is a signal transmission line, 8 is an indoor model box, 8-1 is a cuboid water tank, 8-2 is underwater sediments and 8-3 is water.
Detailed Description
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown.
An underwater sediment deposition characteristic measuring device based on a distributed acoustic wave sensing technology comprises a sensing element, an optical fiber lead, a distributed acoustic wave sensing demodulator, a computer, a signal emitter and a pulse vibrator; one end of the distributed acoustic sensing demodulator is connected with the computer through a signal transmission line, and the other end of the distributed acoustic sensing demodulator is connected with the sensing element through an optical fiber lead; the pulse vibrator is fixed on the top of the sensing element;
further, the sensing element is connected with the strain sensing optical fiber through a mark post; the mark post is a slender rod with a circular cross section, a straight groove is carved on the surface of the mark post, the direction of the groove is parallel to the axial direction of the mark post, the cross section of the groove is triangular, the depth of the groove is 2-4mm, and the strain sensing optical fiber is fixed in the groove by using epoxy resin; the optical fiber lead is connected with the strain sensing optical fiber in the sensing element in a fusion mode;
further, the pulse vibrator comprises three modules: the device comprises a signal receiving module, a pulse vibration module and a power supply module; the three modules are connected through a circuit, the power supply module is responsible for supplying power to other modules, and when the signal receiving module receives a transmitting signal transmitted by the signal transmitter, the pulse vibration module immediately generates pulse vibration to enable the sensing element to vibrate;
the method for measuring the deposition characteristics of the underwater sediments based on the distributed acoustic wave sensing technology based on the measuring device comprises the following steps:
firstly, carrying out a calibration test on a measuring device indoors to obtain an empirical relation curve of the vibration frequency of a sensing element and the type of underwater sediments;
vertically inserting a sensing element in the measuring device into a certain underwater position to be measured, after the device is stabilized, transmitting an excitation signal to a pulse vibrator by using a signal transmitter on the bank, and acquiring and recording strain data of the sensing element during vibration by using a distributed acoustic wave sensing demodulator;
thirdly, extracting data recorded by the distributed acoustic wave sensing demodulator in the second step by using computer software, arranging the recorded strain data according to the sequence from the top to the bottom of the sensing element, and analyzing the strain data of each position so as to determine the interface position of the underwater sediment and the water;
fourthly, performing fast Fourier transform on the recorded strain data, extracting frequency data of the vibration of the sensing element, and judging the type of underwater sediment according to the measured vibration frequency according to an empirical relation curve of the vibration frequency of the sensing element and the type of the underwater sediment;
and fifthly, transmitting an excitation signal at the water bank at regular intervals, repeating the third step and the fourth step to obtain the position of the underwater sediment-water interface and the type of the sediment at the position of the sensing element, comparing the position with the previous measurement result to obtain the lifting condition of the position of the underwater sediment-water interface and the change condition of the type of the sediment, further realizing long-term monitoring of the scouring and silting of the riverbed or lake bed, and judging the type and thickness of the scoured or silted sediment.
Furthermore, the strain sensing optical fibers at different positions record strain information of the sensing elements at different positions, in the first step, the position of the sensing element corresponding to each optical fiber record is determined through a calibration test, and the track number recorded by each optical fiber and the position of the sensing element corresponding to the track number are recorded, so that position reference is provided for later analysis of strain data of the optical fibers.
Furthermore, the empirical relationship between the vibration frequency of the sensing element and the type of the underwater sediments can be obtained through an indoor calibration test, the type of the underwater sediments and the insertion depth of the sensing element are continuously changed for the same sensing element, the sensing element is vibrated through the pulse vibrator to obtain strain data of the vibration of a plurality of sensing elements, the corresponding variable data is subjected to fast Fourier transform to obtain frequency data, and then the frequency data is subjected to visualization processing to obtain the empirical relationship curve between the vibration frequency of the sensing element and the type of the underwater sediments.
Further, in the third step, when the sensing element vibrates, the strain of the sensing element is the largest near the interface position of the sediment and the water, the strain data of each position of the sensing element are compared, the optical fiber channel number with the largest strain is recorded, and the position of the sensing element corresponding to the channel is the interface position of the underwater sediment and the water.
Further, in the fourth step, in order to reduce interference of external environment noise on frequency measurement, denoising processing may be performed on the data, where the denoising processing includes the following steps: firstly, main frequency analysis is carried out on each optical fiber data, then, filtering processing is carried out on the optical fiber data according to the main frequency analysis result, and finally, the optical fiber data after each channel of filtering is overlapped, so that the signal-to-noise ratio can be greatly improved.
Further, in the fourth step, the measured vibration frequency is substituted into the empirical relationship curve to judge the type of the sediment under the effluent.
Example 1
An underwater sediment deposition characteristic measuring device based on a distributed acoustic wave sensing technology comprises a sensing element 1, a distributed acoustic wave sensing demodulator 2, a computer 3, a signal emitter 4, a pulse vibrator 5 and an optical fiber lead 6; one end of the distributed acoustic sensing demodulator 2 is connected with the computer 3 through a signal transmission line 7, and the other end is connected with a strain sensing optical fiber 1-2 in the sensing element 1 through an optical fiber lead 6; the sensing element 1 comprises a mark post 1-1 and a strain sensing optical fiber 1-2; the marker post 1-1 is a slender rod with a circular cross section, a straight groove is carved on the surface of the marker post 1-1, the direction of the groove is parallel to the axial direction of the marker post 1-1, the cross section of the groove is triangular, the depth of the groove is 2-4mm, and the strain sensing optical fiber 1-2 is fixed in the carved groove by epoxy resin; the optical fiber lead 6 is connected with the strain sensing optical fiber 1-2 in the sensing element 1 in a welding mode; the pulse vibrator 5 comprises three modules: the device comprises a signal receiving module 5-1, a pulse vibration module 5-2 and a power supply module 5-3; the three modules are connected through a circuit, the power supply module 5-3 is responsible for supplying power to other modules, when the signal receiving module 5-1 receives a transmitting signal transmitted by the signal transmitter 4, the pulse vibration module 5-2 immediately generates pulse vibration to enable the sensing element 1 to vibrate, and the structural schematic diagram of the measuring device is shown in attached figure 1.
The underwater sediment deposition characteristic measuring method based on the measuring device comprises the following steps:
connecting a measuring device, and carrying out a calibration test on the measuring device indoors; determining the position of the sensing element corresponding to each optical fiber record through a small-sized knock test, and recording the track number of each optical fiber record and the position of the sensing element corresponding to the track number; then vertically inserting the sensing element 1 into an indoor model box 8, continuously changing the type of the underwater sediments 8-2 and the insertion depth of the sensing element 1, and vibrating the sensing element 1 through a pulse vibrator 5 to obtain frequency data of vibration of a plurality of sensing elements 1, wherein in the diagram of the indoor calibration test, 8-1 is a cuboid water tank, 8-2 is added underwater sediments, and 8-3 is added water in the diagram of fig. 2; an empirical relation curve of the vibration frequency of the sensing element 1 and the type of the underwater sediment 8-2 is obtained by performing visual processing on the vibration frequency data;
step two, vertically inserting a sensing element 1 in a measuring device into a position to be measured, after the device is stabilized, transmitting an excitation signal to a pulse vibrator 5 by using a signal transmitter 4 on the water bank side, and acquiring and recording strain data of the sensing element 1 during vibration by using a distributed sound wave sensing demodulator 2;
thirdly, extracting data recorded by the distributed acoustic wave sensing demodulator 2 in the second step by using computer software, and arranging the recorded strain data according to the sequence from the top to the bottom of the sensing element 1, wherein the strain change rule of the sensing element 1 is as follows according to mechanics knowledge: from the top to the bottom of the sensing element 1, the strain is firstly increased and then immediately decreased, the strain of the sensing element 1 is the largest near the interface position of the underwater sediment and the water, therefore, the strain data of each position of the sensing element 1 is analyzed, the optical fiber channel number with the largest strain is recorded, and the position of the sensing element corresponding to the channel is the interface position of the underwater sediment and the water;
fourthly, performing fast Fourier transform on the recorded strain data, extracting frequency data of vibration of the sensing element 1, and judging the type of underwater sediment according to the measured vibration frequency according to an empirical relation curve of the vibration frequency of the sensing element 1 and the type of the underwater sediment;
in the first step, the empirical relationship between the vibration frequency of the sensing element 1 and the type of the underwater sediments is obtained through an indoor calibration test, and the test principle is as follows;
based on the winkler foundation model, the underwater sediments are considered as n mutually independent springs, n is a natural number, and the specific figure is shown in figure 3, wherein the rigidity K of each springiCan be expressed as:
Ki＝k*xiDa\*MERGEFORMAT (1)
wherein x isiIs the depth, k, of each spring*Representing the proportionality coefficient of the underwater deposit, D is the diameter of the sensing element 1 and a is the thickness of each spring in the deposit.
The scaling factors of different underwater sediments 8-2 are obviously different, and the reference values of the scaling factors of the underwater sediments are listed in the table 1;
for the same sensing element 1, continuously changing the type of the underwater sediments 8-2 and the insertion depth of the sensing element 1, obtaining frequency data of vibration of a plurality of sensing elements 1 through an indoor calibration test, and carrying out visual processing on the frequency data of vibration to obtain an empirical relation graph of the vibration frequency of the sensing elements 1 and the type of the underwater sediments;
in fig. 3, H represents the insertion depth of the sensing element 1, L represents the total length of the sensing element, and L represents the cantilever length of the sensing element, and the relationship between the three can be expressed as follows:
l＝L-H\*MERGEFORMAT (2)
determining the interface position of underwater sediment-water in the third step, and calculating the insertion depth H of the sensing element and the cantilever length l of the sensing element according to the interface position;
and substituting the frequency data of the sensing element 1 during free vibration and the cantilever length l of the sensing element 1 into an empirical relationship chart to judge the type of the underwater sediment.
TABLE 1 reference values for the scaling factor of underwater sediments
In the fourth step, in order to reduce the interference of the external environment noise on the frequency measurement, the data may be denoised first, and the denoising process includes the following steps: firstly, main frequency analysis is carried out on each optical fiber data, then, filtering processing is carried out on the optical fiber data according to the main frequency analysis result, and finally, the optical fiber data after each channel of filtering is overlapped, so that the signal-to-noise ratio can be greatly improved.
And fifthly, transmitting an excitation signal at the water bank at regular intervals, repeating the third step and the fourth step, measuring the position of the underwater sediment-water interface and the type of the sediment at the position of the sensing element, comparing the position with the previous measurement result, obtaining the lifting condition of the position of the underwater sediment-water interface and the change condition of the type of the sediment, further realizing long-term monitoring on the scouring and silting of the seabed, the river bed or the lake bed, and judging the type and the thickness of the scoured or silted sediment.
Example 2:
an underwater sediment deposition characteristic measuring device based on a distributed acoustic wave sensing technology comprises a sensing element 1, a distributed acoustic wave sensing demodulator 2, a computer 3, a signal emitter 4, a pulse vibrator 5 and an optical fiber lead 6; one end of the distributed acoustic sensing demodulator 2 is connected with the computer 3 through a signal transmission line 7, and the other end is connected with the sensing element 1 through an optical fiber lead 6; the sensing element 1 comprises a mark post 1-1 and a strain sensing optical fiber 1-2, the mark post 1-1 is a slender rod with a circular section, as a preferred embodiment of the invention, the mark post is an aluminum alloy rod, the length of the rod is 1.5m, the radius is 2cm, a straight groove is carved on the surface of the mark post 1-1, the direction of the groove is parallel to the axial direction of the mark post 1-1, the section of the groove is triangular, the depth of the groove is 2-4mm, the strain sensing optical fiber 1-2 is placed in the groove, and is fixed in the groove by epoxy resin; the optical fiber lead 6 is connected with the strain sensing optical fiber 1-2 in a fusion mode; the pulse vibrator 5 comprises three modules: the device comprises a signal receiving module 5-1, a pulse vibration module 5-2 and a power supply module 5-3; the three modules are connected through a circuit, the power supply module 5-3 is responsible for supplying power to other modules, and when the signal receiving module 5-1 receives a transmitting signal transmitted by the signal transmitter 4, the pulse vibration module 5-2 immediately generates pulse vibration to enable the sensing element 1 to vibrate.
The method for measuring the deposition characteristics of the underwater sediments based on the distributed acoustic sensing technology comprises the following steps:
connecting the measuring device, performing an indoor calibration experiment, determining the position of the sensing element 1 corresponding to each optical fiber record through a small-sized knock test, and recording the track number of each optical fiber record and the position of the sensing element 1 corresponding to the track number; then vertically inserting the sensing element 1 into an indoor model box 8, continuously changing the type of underwater sediments 8-2 and the insertion depth of the sensing element 1, and vibrating the sensing element 1 through a pulse vibrator 5 to obtain frequency data of vibration of a plurality of sensing elements 1. In this example, the indoor model box 8 comprises a cuboid water tank 8-1 with a length × width × height of 100cm × 60cm × 130cm, an underwater sediment 8-2 and water 8-3, and the obtained vibration frequency data is subjected to visualization processing to obtain an empirical relationship curve of the vibration frequency of the sensing element 1 and the type of the underwater sediment 8-2, as shown in fig. 4 specifically;
step three, performing a field test, vertically inserting a sensing element 1 in a measuring device into a certain position to be measured of a riverbed, after the device is stabilized, transmitting an excitation signal to a pulse vibrator 5 by using a signal transmitter 4 on the water bank side, and acquiring and recording strain data of the sensing element 1 during vibration by using a distributed sound wave sensing demodulator 2;
extracting data recorded by the distributed acoustic wave sensing demodulator 2 in the third step by using computer software, arranging the recorded optical fiber data according to the sequence from the top to the bottom of the sensing element 1, comparing the optical fiber data of each position of the sensing element 1, finding the position 100cm away from the top of the sensing element, and judging that the position is the position of an underwater sediment-lake water interface, wherein the strain of the data recorded by the optical fiber is the maximum at each time point, and the result is basically consistent with the actual situation on site;
fifthly, denoising the recorded strain data, namely firstly carrying out main frequency division on each optical fiber dataAnalyzing, filtering the optical fiber data of each channel according to the main frequency analysis result, finally superposing the filtered data, performing fast Fourier transform on the superposed data, and extracting the vibration frequency f of the sensing element 1 by a peak extraction method1，f15.5Hz, the vibration frequency f of the sensing element 11Substituting the measured position into an empirical relationship curve, as shown in fig. 5, judging that the type of the underwater sediment at the measured position is broken stone according to the empirical relationship curve, and enabling a test result to be consistent with the actual situation on site;
after the sixth step and 4 weeks, transmitting an excitation signal to the pulse vibrator on the water bank again, repeating the third step to the fifth step, finding the position 80cm away from the top of the sensing element, determining that the position is the position of the interface between the underwater sediment and the lake water, wherein the result is basically consistent with the actual situation on site, and the vibration frequency f of the sensing element2About 6.5Hz, and f2And introducing an empirical relation curve, as shown in fig. 6, judging that the type of the underwater sediment at the measuring position is fine sand, wherein the test result is basically consistent with the actual situation on site, and the results of two experiments show that the fine sand carried in river water is deposited in the transportation process, the rising of the sediment-water interface position caused by deposition can be clearly monitored, and the type of the sediment and the thickness of the deposit can be measured.
In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.
Claims (9)
1. The device for measuring the deposition characteristics of the underwater sediments based on the distributed acoustic wave sensing technology is characterized by comprising a sensing element, a distributed acoustic wave sensing demodulator, an optical fiber lead, a computer, a signal emitter and a pulse vibrator; one end of the distributed acoustic wave sensing demodulator is connected with the computer through a signal transmission line, and the other end of the distributed acoustic wave sensing demodulator is connected with the sensing element through an optical fiber lead; the pulse vibrator is fixed on the top of the sensing element; the sensing element consists of a post and a strain sensing optical fiber, and the strain sensing optical fiber is embedded in the post.
2. The device for measuring the deposition characteristics of the underwater sediments based on the distributed acoustic wave sensing technology as claimed in claim 1, is characterized in that: the marker post is a slender rod with a circular section, the surface of the marker post is provided with a groove, the direction of the groove is parallel to the axial direction of the marker post, and the strain sensing optical fiber is fixed in the groove; the fiber optic pigtail is connected to a strain sensing fiber in the sensing element.
3. The device for measuring the deposition characteristics of underwater sediments based on the distributed acoustic wave sensing technology as claimed in claim 1, wherein said pulse vibrator comprises three modules: the device comprises a signal receiving module, a pulse vibration module and a power supply module; the three modules are electrically connected, the power supply module is responsible for supplying power to other modules, and when the signal receiving module receives a transmitting signal transmitted by the signal transmitter, the pulse vibration module immediately generates pulse vibration to enable the sensing element to vibrate.
4. The measuring method of the underwater sediment deposition characteristic measuring device based on the distributed acoustic sensing technology is characterized by comprising the following steps:
firstly, carrying out a calibration test on a measuring device indoors to obtain an empirical relation curve of the vibration frequency of a sensing element and the type of underwater sediments;
vertically inserting a sensing element in the measuring device into a certain underwater position to be measured, after the device is stabilized, transmitting an excitation signal to a pulse vibrator by using a signal transmitter on the bank, and acquiring and recording strain data of the sensing element during vibration by using a distributed acoustic wave sensing demodulator;
thirdly, extracting data recorded by the distributed acoustic wave sensing demodulator in the second step by using computer software, arranging the recorded strain data according to the sequence from the top to the bottom of the sensing element, and analyzing the strain data of each position so as to determine the interface position of the underwater sediment and the water;
fourthly, performing fast Fourier transform on the recorded strain data, extracting frequency data of the vibration of the sensing element, and judging the type of underwater sediment according to the measured vibration frequency according to an empirical relation curve of the vibration frequency of the sensing element and the type of the underwater sediment;
and step five, transmitting signals at the water bank side by using a signal transmitter at regular intervals, repeating the step three and the step four, measuring the position of the underwater sediment-water interface and the type of the sediment at the position of the sensing element, comparing the position with the previous measurement result, obtaining the lifting condition of the position of the underwater sediment-water interface and the change condition of the type of the sediment, further realizing long-term monitoring of the scouring or siltation of the seabed, the river bed and the lake bed, and judging the type and the thickness of the scoured or silted sediment.
5. The measurement method according to claim 4, characterized in that: in the first step, the position of the sensing element corresponding to each optical fiber record is determined through a calibration test, the track number of each optical fiber and the position of the corresponding sensing element are recorded, and position reference is provided for later analysis of strain data of the optical fiber.
6. The measurement method according to claim 4, characterized in that: the method comprises the steps of obtaining an empirical relationship between the vibration frequency of a sensing element and the type of underwater sediments through an indoor calibration test, continuously changing the type of the underwater sediments and the insertion depth of the sensing element for the same sensing element, vibrating the sensing element by using a pulse vibrator to obtain frequency data of vibration of a plurality of sensing elements, and then carrying out visualization processing on the frequency data to obtain an empirical relationship curve between the vibration frequency of the sensing element and the type of the underwater sediments.
7. The measurement method according to claim 4, characterized in that: and in the third step, when the sensing element vibrates, the strain of the sensing element is maximum near the interface position of the sediment and the water, the strain data of each position of the sensing element is compared, the optical fiber channel number with the maximum strain is recorded, and the position of the sensing element corresponding to the channel is the interface position of the underwater sediment and the water.
8. The measurement method according to claim 4, characterized in that: in the fourth step, in order to reduce the interference of the external environment noise on the frequency measurement, the data is denoised firstly, and the denoising process comprises the following steps: firstly, main frequency analysis is carried out on each optical fiber data, then, filtering processing is carried out on the optical fiber data according to the main frequency analysis result, and finally, the optical fiber data after each channel of filtering is overlapped, so that the signal-to-noise ratio is improved.
9. The measurement method according to claim 4, characterized in that: and step four, substituting the measured vibration frequency into the empirical relation curve to judge the type of the sediment in the water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110068569.1A CN112904409B (en) | 2021-01-19 | 2021-01-19 | Device and method for measuring deposition characteristics of underwater sediments based on distributed acoustic sensing technology |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110068569.1A CN112904409B (en) | 2021-01-19 | 2021-01-19 | Device and method for measuring deposition characteristics of underwater sediments based on distributed acoustic sensing technology |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112904409A true CN112904409A (en) | 2021-06-04 |
| CN112904409B CN112904409B (en) | 2022-05-03 |
Family
ID=76115572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110068569.1A Active CN112904409B (en) | 2021-01-19 | 2021-01-19 | Device and method for measuring deposition characteristics of underwater sediments based on distributed acoustic sensing technology |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112904409B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114370925A (en) * | 2021-12-06 | 2022-04-19 | 南京大学 | Method for determining distributed optical fiber sensing channel |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2412041A1 (en) * | 2000-06-29 | 2002-07-25 | Paulo S. Tubel | Method and system for monitoring smart structures utilizing distributed optical sensors |
| CN102345796A (en) * | 2010-07-28 | 2012-02-08 | 中国石油天然气股份有限公司 | Method for monitoring oil-gas pipeline in mining subsidence area |
| GB201212701D0 (en) * | 2012-07-17 | 2012-08-29 | Silixa Ltd | Structure monitoring |
| CN102829987A (en) * | 2011-06-17 | 2012-12-19 | 中国石油天然气集团公司 | Method for measuring ice load of ocean platform |
| CN103700223A (en) * | 2012-09-28 | 2014-04-02 | 中国石油天然气股份有限公司 | Oil-gas pipeline torrential flood disaster monitoring system |
| CN104007175A (en) * | 2014-05-09 | 2014-08-27 | 华南理工大学 | Multi-crack damage identification apparatus and method for cantilever flexible beam |
| US20170075029A1 (en) * | 2015-09-16 | 2017-03-16 | Schlumberger Technology Corporation | Method and system for calibrating a distributed vibration sensing system |
| CN108180976A (en) * | 2017-12-22 | 2018-06-19 | 武汉理工大学 | The method that vibration state and friction coefficient based on fiber grating measure simultaneously |
| CN108279211A (en) * | 2018-03-25 | 2018-07-13 | 南京大学 | A kind of quasi-distributed system, sensing device and method measuring soil moisture content |
| CN208187389U (en) * | 2018-03-30 | 2018-12-04 | 胡仲春 | tunnel monitoring system |
-
2021
- 2021-01-19 CN CN202110068569.1A patent/CN112904409B/en active Active
Patent Citations (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2412041A1 (en) * | 2000-06-29 | 2002-07-25 | Paulo S. Tubel | Method and system for monitoring smart structures utilizing distributed optical sensors |
| US20030094281A1 (en) * | 2000-06-29 | 2003-05-22 | Tubel Paulo S. | Method and system for monitoring smart structures utilizing distributed optical sensors |
| CN102345796A (en) * | 2010-07-28 | 2012-02-08 | 中国石油天然气股份有限公司 | Method for monitoring oil-gas pipeline in mining subsidence area |
| CN102829987A (en) * | 2011-06-17 | 2012-12-19 | 中国石油天然气集团公司 | Method for measuring ice load of ocean platform |
| GB201212701D0 (en) * | 2012-07-17 | 2012-08-29 | Silixa Ltd | Structure monitoring |
| CN103700223A (en) * | 2012-09-28 | 2014-04-02 | 中国石油天然气股份有限公司 | Oil-gas pipeline torrential flood disaster monitoring system |
| CN104007175A (en) * | 2014-05-09 | 2014-08-27 | 华南理工大学 | Multi-crack damage identification apparatus and method for cantilever flexible beam |
| US20170075029A1 (en) * | 2015-09-16 | 2017-03-16 | Schlumberger Technology Corporation | Method and system for calibrating a distributed vibration sensing system |
| CN108180976A (en) * | 2017-12-22 | 2018-06-19 | 武汉理工大学 | The method that vibration state and friction coefficient based on fiber grating measure simultaneously |
| CN108279211A (en) * | 2018-03-25 | 2018-07-13 | 南京大学 | A kind of quasi-distributed system, sensing device and method measuring soil moisture content |
| CN208187389U (en) * | 2018-03-30 | 2018-12-04 | 胡仲春 | tunnel monitoring system |
Non-Patent Citations (2)
| Title |
|---|
| CHENG-CHENG ZHANG, HONG-HU ZHU, BIN SHI1: "Role of the interface between", 《SCIENCE REPORTS》 * |
| 程刚，施斌，朱鸿鹄: "光纤和砂土界面耦合性能的分布式感测试验研究", 《高校地质学报》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114370925A (en) * | 2021-12-06 | 2022-04-19 | 南京大学 | Method for determining distributed optical fiber sensing channel |
| CN114370925B (en) * | 2021-12-06 | 2022-10-18 | 南京大学 | Method for determining distributed optical fiber sensing channel |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112904409B (en) | 2022-05-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110208859B (en) | Intelligent calculation method for quantitative parameters of oil-based mud well fractures based on ultrasonic imaging | |
| CN1330771A (en) | Method for determination of local wave heights and acoustic sensor in marine seismic signals | |
| US8639442B2 (en) | Identifying invalid seismic data | |
| CN1555496A (en) | Determination of the height of the surface of a fluid column | |
| FR2965066A1 (en) | METHOD FOR ESTIMATING ELASTIC PARAMETERS BY INVERTING SEISMIC 4D MEASUREMENTS | |
| CN100456045C (en) | Method and system for measuring sea bed deposite sediment property by shallow stratigraphic section instrument | |
| CN112904409B (en) | Device and method for measuring deposition characteristics of underwater sediments based on distributed acoustic sensing technology | |
| CN112857698B (en) | Method for detecting wall leakage based on surface acoustic waves | |
| EP2669715A2 (en) | Methods and Systems for Computing Notional Source Signatures From Near-Field Measurements and Modeled Notional Signatures | |
| FR2963111A1 (en) | METHOD FOR ESTIMATING ELASTIC PARAMETERS BY INVERTING SEISMIC 4D MEASUREMENTS | |
| CN109541689B (en) | Method for evaluating compactness of medium based on reflected wave energy characteristics | |
| CN114216516A (en) | Sound-temperature synchronous detection sampling device and method for cable-controlled submarine sediment | |
| Madsen et al. | Simultaneous multiwell VSP using distributed acoustic sensing | |
| CN112835124A (en) | Fracture effectiveness evaluation method based on imaging logging and array acoustic logging data | |
| CN209911570U (en) | Optical fiber time-frequency electromagnetic and four-component seismic data acquisition device in well | |
| CN115980758A (en) | Mud line position tester integrated in seabed in-situ equipment and identification method | |
| CN202676668U (en) | Self-adaptive device for sound response simulation experiment of hydrates in samples of different sizes | |
| CN116519056A (en) | River bottom siltation dynamic monitoring method based on unmanned ship | |
| CN103410134B (en) | Conical probe for ocean under-consolidated soil pore water pressure testing | |
| CN206056530U (en) | For realizing the depth finding device of bottom sediment depth survey | |
| CN103123397A (en) | Processing multi-component seismic data | |
| CN215180930U (en) | Small-scale in-situ acoustic imaging system for seabed sediment | |
| CN2919231Y (en) | Device for measuring intensity and deformation performance of abyssal surface sediment | |
| CN109490962A (en) | A kind of removing method of shallow seismic profile Non-zero Offset | |
| Ertel et al. | Advances in pile integrity testing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |