WO2014201751A1

WO2014201751A1 - Probe and device for monitoring imminent earthquake

Info

Publication number: WO2014201751A1
Application number: PCT/CN2013/079810
Authority: WO
Inventors: 王新安; 林科; 张兴; 雍珊珊; 王腾; 谢峥; 郭朝阳; 张国新; 冯晓星; 葛彬杰; 周中华; 安辉耀
Original assignee: 北京大学深圳研究生院
Priority date: 2013-06-17
Filing date: 2013-07-22
Publication date: 2014-12-24
Also published as: CN103353608A

Abstract

A probe for monitoring an imminent earthquake, comprising: a soniferous head (10) used for directly coupling to a point to be detected; a plurality of groups of sensors (30) used for converting earthquake sound signals into electrical signals; a preprocessing circuit module (50) used for conducting signal filtering, amplification and analogue-to-digital conversion on the electrical signals in sequence; and a power supply and signal cable (60) used for transmitting output signals of the preprocessing circuit module (50) and providing a power supply for the preprocessing circuit module (50), wherein the power supply output end and the signal input end of the power supply and signal cable (60), and the plurality of groups of sensors (30) and the preprocessing circuit module (50) are packaged through a packaging structure (40 ) and fixed at the output end of the soniferous head (10). Since a frequency response range of sensor groups covers sound wave frequency bands of different earthquake sounds, a probe is able to capture the intensity, frequentness and frequency of different earthquake sound information, thereby being applicable to monitor the earthquake inoculation process and imminent earthquake prediction work; meanwhile, one sensor in each group of the sensor groups can be used as a backup of the other sensor, so that the reliability of the probe can be improved. Further provided is a device for monitoring an imminent earthquake.

Description

Probe and device for seismic earthquake monitoring

The present application relates to the field of seismic monitoring technology, and particularly relates to a probe for seismic earthquake monitoring and a device for monitoring earthquake seismic.

Background technique

Through constant movement and change, the earth gradually accumulates energy in certain fragile zones of the earth's crust. Once the accumulated energy is huge, it will cause the rock to suddenly rupture or cause the original fault to be displaced. This is an earthquake. China is one of the countries with the most serious earthquake disasters on the global continent. On the land area of 1 / 14 of the world's land area, the number of earthquakes per year accounts for more than one third of the number of global land earthquakes. Strengthening countermeasures for earthquake disasters, improving the technical level of earthquake monitoring and forecasting, and mitigating earthquake disasters are directly related and significant to the stability of the country's development society and the safety of people's lives and property.

Before the major earthquake, the local stress field distribution is an unstable state in places where stress is easily concentrated in the earth's crust, such as faults, cracks and voids. When this unsteady stress field continues to accumulate energy, the redistribution of the stress field occurs at a critical point. The redistribution process of the stress field or the release process of the strain energy is the deformation and microscopic fracture of the rock mass. The cracks are then developed into large-scale fractures (seismic) of the rock mass. The part of the released energy is released in the form of sound waves. During the micro-fracture and crack generation before the large-scale fracture (seismic) of the rock mass, the radiated sound waves are the pre-earthquake ground sounds. Therefore, the detection of geoacoustic signals in seismic fault zones has become an important method for monitoring crustal activity. The technological innovations in this area will certainly have a positive effect on the exploration of earthquake inoculation process, fault activity, and prediction and prediction of large earthquakes.

Summary of the invention

According to a first aspect of the present application, the present application provides a probe for seismic earthquake monitoring, comprising: a sound head for directly coupling with a point to be measured to capture a ground sound signal; and for converting the ground sound signal a plurality of sets of sensors for electrical signals, each set of sensors comprising at least two independent sensors, the frequency response ranges of the plurality of sets of sensors covering different acoustic acoustic wave frequency bands; for sequentially filtering, amplifying, and modulating the electrical signals a digital conversion preprocessing circuit module; a power supply and signal cable for transmitting an output signal of the preprocessing circuit module and providing power to the preprocessing circuit module; a power supply output end and a signal input of the power supply and signal cable End, the plurality of sets of sensors and the pre-processing circuit module are packaged and fixed to an output end of the sounding head by a package structure, a power supply input end and a signal output of the power supply and signal cable The end protrudes from the package structure.

Further, the probe further includes a sounding rod for transmitting the ground acoustic signal to the plurality of sets of sensors, each set of sensors comprising at least two independent piezoelectric thin film sensors, each of the piezoelectric thin film sensors Attached to the surface of the sounding rod.

Preferably, the package structure is further used for encapsulating the sounding rod; the cross section of the sounding rod is a polygon, and the number of sides of the polygon is equal to the number of all the piezoelectric film sensors.

Preferably, the sounding rod is a solid rigid structure, and the sounding rod is provided with a connecting end at one end connected to the sounding head; the sounding head is a solid rigid structure, and the sounding head is used A connecting hole is disposed at one end connected to the sounding rod, and the connecting head is matched with the connecting hole.

Preferably, the diameter of the input end of the sounding head is smaller than the diameter of the output end thereof; the package structure supplies the power supply output end and the signal input end of the power supply and signal cable, the plurality of sets of sensors and the pre-processing circuit module The package is fixed in a cylindrical space of equal diameter to the output end of the acoustic head.

Further, the plurality of sets of sensors includes at least one set of infrasound sensors, at least one set of audible wave sensors, and at least one set of ultrasonic sensors.

Further, the pre-processing circuit module includes a plurality of signal processing links, the plurality of signal processing links are independent of each other, juxtaposed and identical, and are used for sequentially filtering, amplifying, and modulating the electrical signals in parallel. After the conversion, the number of the signal processing links is the same as the number of groups of the plurality of groups of sensors, and one signal processing link is connected to a group of sensors, and each group of sensors converts the electricity converted by each of the sensors included therein The signals are added and output to a corresponding signal processing link.

Further, each of the plurality of sets of sensors is a backup of other sets of sensors, and one of each set of sensors is a backup of other sensors of the set of sensors; each of the plurality of signal processing links The signal processing link is a backup of other signal processing links.

According to a second aspect of the present application, the present application provides an apparatus for seismic earthquake monitoring, comprising: a probe for seismic earthquake monitoring as described above, for selecting a processed signal from the pre-processing circuit module a master unit, and a wireless transmitting unit for transmitting the selected signal.

Further, the main control unit selects the strongest signal from the pre-processing circuit module Output signal.

The beneficial effects of the present application are: Since the frequency response range of the sensor group covers different acoustic acoustic wave frequency bands, the probe can capture the intensity, frequency and frequency of different geoacoustic information, and is suitable for monitoring the earthquake inoculation process and the imminent earthquake prediction work; At the same time, there are at least two sensors in each group of sensors, and one of the sensors can be used as a backup for the other, thereby improving the reliability of the probe.

DRAWINGS

1 is a schematic structural view of a probe for seismic earthquake monitoring according to an embodiment of the present application; FIG. 2 is a schematic cross-sectional view of the probe shown in FIG. 1;

3 is a schematic structural view of a sound transmitting head of a probe in an embodiment of the present application;

4 is a schematic structural view of a sound transmission rod of a probe in an embodiment of the present application;

5 is a schematic diagram of a sensor group of a probe connected to a pre-processing circuit module in an embodiment of the present application;

6 is a schematic structural diagram of a pre-processing circuit module of a probe connected to a ground base station in an embodiment of the present application.

detailed description

The embodiment of the present application provides a probe for seismic earthquake monitoring, which comprises a sound head, a plurality of sensors, a pre-processing circuit module, a power supply and signal cable, and a package structure. The sound head is used to directly couple with a point to be measured, such as a bedrock, to capture a ground sound signal. Multiple sets of sensors are used to convert the ground acoustic signals captured by the acoustic head into electrical signals. Each set of sensors includes at least two independent sensors whose frequency response ranges cover different acoustic acoustic wave bands. The pre-processing circuit module is used for sequentially performing signal filtering, amplification, and analog-to-digital conversion on the electrical signal. The power supply and signal cable have two functions of power supply and signal transmission, that is, it is used to transmit the output signal of the pre-processing circuit module, and is also used to supply power to the pre-processing circuit module. The package structure is used for packaging and fixing the power supply output and the signal input end of the plurality of sensors, the pre-processing circuit module and the power supply and signal cable to the output end of the sound head, and the power supply input terminal and the signal output end of the power supply and signal cable It is exposed outside the package structure. Here, the power supply output and signal input end of the power supply and signal cable refer to the end of the power supply and signal cable connected to the pre-processing circuit module. Obviously, the power supply input terminal and the signal output end of the power supply and signal cable refer to the pre-processing circuit module. One end.

The present invention will be further described in detail below with reference to the accompanying drawings.

Example 1

As shown in FIG. 1 and FIG. 2, the probe for seismic earthquake monitoring of the present embodiment includes a sounding head 10, A plurality of sets of sensors 30, a pre-processing circuit module 50, a power supply and signal cable 60, and a package structure 40, wherein the plurality of sets of sensors 30 are a plurality of sets of strip-shaped piezoelectric film sensors, and the probe further comprises a transistor for facilitating the fixing of the strip-shaped piezoelectric film sensor. Sound rod 20.

The horn 10 is used to directly couple with the bedrock and to transmit the ground acoustic signal to the plurality of sets of sensors 30. In one implementation, the diameter of the input end of the acoustic head can be set smaller than the diameter of the output end, wherein the input end refers to the end of the acoustic head that first contacts the bedrock, and the output end is the end opposite the input end, such as sound transmission. The head may be pointed or tapered and may be shaped like a bullet. In another implementation, the acoustic head is a solid rigid structure. In particular, the acoustic head can be made of a corrosion-resistant metal material in order to be placed on the ground without damage and to better capture the acoustic signal.

The sounding rod 20 is used to fix the strip-shaped piezoelectric film sensor group 30, and transmits the ground sound signal from the sound transmitting head 10 to the strip-shaped piezoelectric film sensor group 30, each of which includes at least two independent Piezoelectric film sensors, each of which is attached to the surface of the sounding rod. In one implementation, the cross section of the sounding rod is a polygon, and the number of sides of the polygon is equal to the number of all strip-shaped piezoelectric film sensors. In another implementation, the sounding rod is a solid rigid structure, the sounding rod is provided with a connecting end at one end connected to the sounding head, and the connecting end of the sounding head for connecting with the sounding rod is provided with a connecting hole, and the connecting The head is mated with the connection hole.

For example, as shown in FIG. 3 and FIG. 4, in a specific implementation, the material of the conical sounding head 10 and the sounding rod 20 are solid stainless steel, wherein the bottom surface of the conical sound head (ie, the output end) It is a circle with a radius of 5 cm and a height of 15 cm. The center of the bottom surface has a threaded connection hole 101 with a diameter of 3 cm, and the sounding rod 20 is 30 cm long, and the cross section is a regular hexagon with a side length of 3 cm, which is linked with the sound head. The end portion has a threaded connector 201 having a diameter of 3 cm; the tapered microphone head 10 is mechanically coupled to the sounding rod 20 by a threaded connection hole 101 and a threaded connection head 201.

In this embodiment, the plurality of sets of sensors are a plurality of sets of piezoelectric thin film sensors for converting the received ground acoustic signals into electrical signals. Still taking the specific implementation mentioned above as an example, there are three sets of piezoelectric film sensors, two sensors per group, that is, six independent piezoelectric film sensors, for example, polyvinylidene fluoride (PVDF) pressure. The electric film is packaged in a metal strip package, 20cm long and 2cm wide. It is glued to the six sides of the sound rod. Its sensitivity should be better than -180dB-Vxl0 ⁴ /Pa, and the frequency response range is greater than 10" ³ Hz to less than 10 ⁵ Hz, operating temperature range greater than -50 ° C to less than 100 ° C.

The pre-processing circuit module 50 is configured to perform signal filtering and amplification on the transmitted electrical signal, and convert the analog quantity into a digital quantity and output. Specifically, the pre-processing circuit module includes a plurality of juxtapositions Signal processing link, each signal processing link is independent and identical to each other, the number of signal processing links is the same as the number of groups of multiple sets of sensors, and one signal processing link is connected to a group of sensors, since each group of sensors includes At least two sensors, such that the sum of the signals output by each of the sensors in each set of sensors is the output of the set of sensors, which is delivered to a corresponding signal processing link in the pre-processing circuit module. In one implementation, the filtering and amplifier bandwidth used for each signal processing link is DC-lMHz, ie 0Ηζ~1ΜΗζ, and the analog-to-digital converter uses a ΣΔ analog-to-digital converter.

Still taking the specific implementation as described above as an example, as shown in FIG. 5, at this time, the plurality of sets of sensor groups 30 include six strip-shaped piezoelectric film sensors 3011, 3012, 3021, 3022, 3031, 3032, which are composed of two pairs. The three pairs of strip-shaped piezoelectric film sensor pairs, that is, the sensor 3011 and the sensor 3012 form a pair 301, the sensor 3021 and the sensor 3022 form a pair 302, the sensor 3031 and the sensor 3032 form a pair 303, each pair of strip-shaped piezoelectric film sensor pairs The electrical signals of each of the strip-shaped piezoelectric film sensors are summed and outputted to corresponding signal processing links in the pre-processing circuit module, and the pre-processing circuit module 50 includes three signal processing links 501, 502, 503, each The strip links include filtering and amplifiers 5011, 5012, 5013 and analog to digital converters 5021, 5022, 5023 that are connected in sequence. The three links output the processed signals in parallel.

In the embodiment, each group of sensors and the other group of sensors are backed up with each other, and one of each group of sensors and the other sensors of the group of sensors are also backed up each other. In addition, each signal processing link in the preprocessing circuit module is The other signal processing links are backups of each other. Still taking the foregoing specific implementation as an example, in the three sets of strip-shaped piezoelectric film sensors, each pair of strip-shaped piezoelectric film sensors are mutually backed up by two pairs, each of each pair of strip-shaped piezoelectric film sensors The piezoelectric film sensors are mutually backed up, and each of the three signal processing links is backed up by two other.

In the specific implementation, the pre-processing circuit module can be installed in the metal shielding box, and the input/output interface is reserved by the SMA (SubMini a ture Ver s i on A, 3⁄4 A) connector.

The package structure 40 is used for encapsulating and fixing the power supply output end and the signal input end of the sounding rod 20, the plurality of sets of sensors 30, the pre-processing circuit module 50, the power supply and signal cable 60, and fixing the signal to the output end of the sound head, and supplying power and signals The power supply input and signal output of the cable 60 are exposed outside of the package structure 40, as shown in FIG. In one implementation, the package structure 40 encloses and fixes the power supply output end and the signal input end of the sounding rod 20, the plurality of sets of sensors 30, the pre-processing circuit module 50, the power supply and signal cable 60, and the cone-shaped head 1 Within the cylindrical space of diameter. The package structure 40 should allow the entire probe, of course, in addition to the acoustic head, to be resistant to corrosion, water and friction. Still taking the specific implementation as described above as an example, the steps of assembling and using the probe are as follows: Step 1: attach the strip-shaped piezoelectric film sensor group 30 to the side of the sounding rod 20; Step 2, the sound rod 20 and the cone The voice head 10 is connected;

Step 3: connecting the strip-shaped piezoelectric film sensor group 30, the power supply and signal cable 60 and the pre-processing circuit 50 by coaxial lines;

Step 4: Put the connected probe into the mold, and expose only the power supply input terminal and the signal output end of the cone-shaped head 1 and the power supply and signal cable 6. The glue used should be corrosion-resistant, waterproof, and hard. And anti-friction.

Finally, the assembled probe is installed in a bedrock 150 to 200 meters underground and potted with non-expanded cement, where the cone-shaped head must be directly coupled to the bedrock.

It can be seen that the probe of the embodiment has the following advantages:

(1) Because the geoacoustic information includes high-frequency ultrasonic waves generated during the earthquake inoculation process or before the earthquake, and the small fractures and micro-fractures around the subsurface rock section, including the macroscopic rupture of the bedrock before the earthquake and the process of crustal creep The low-frequency audible wave and the infrasound wave are generated. Therefore, the piezoelectric film sensor used in the embodiment is used as a ground acoustic wave detecting element. Since the piezoelectric film has high sensitivity and a large dynamic range, the frequency response range covers infrasound waves, audible waves, and ultrasonic waves. , so that the probe can completely capture the intensity, frequency and frequency of the ground acoustic information, and is suitable for monitoring the large earthquake incubation process and imminent earthquake prediction work;

(2) One difficulty in the ground sound monitoring work before the earthquake is that it is difficult to select a suitable deep water well as a ground sound observation well, and the probe of this embodiment is easy to manufacture, corrosion resistant, waterproof, and anti-friction, and its installation method and existing drilling technology Compatible, low installation cost, suitable for large-scale, densely arranged ground sound monitoring points;

(3) Another difficulty in ground sound monitoring before the earthquake is that it is difficult to continuously monitor for a long time. It requires very good reliability of the instrument or equipment. However, due to the complex underground environment, the reliability of the sensor, processing circuit and transmission process. There are demanding requirements. In this regard, the probe of the present embodiment backs up the captured geoacoustic signals from the sensor, the processing of the pre-processing circuit and the output thereof, thereby improving the reliability of the probe and making the probe suitable for 150 meters underground. The ground acoustic signal is monitored stably for a long time at 200 meters.

Example 2:

This embodiment provides a probe for seismic earthquake monitoring, similar to Embodiment 1, which includes a sound head, a plurality of sets of sensors, a pre-processing circuit module, a power supply and signal cable, and a package structure. Description of the microphone head, pre-processing circuit module, power supply and signal cable, and package structure Reference can be made to Example 1. The difference in this embodiment is that at this time, the plurality of sets of sensors are at least one set of infrasound sensors, at least one set of audible wave sensors, and at least one set of ultrasonic sensors. Therefore, the embodiment does not require a sound rod, but may The infrasonic wave sensor, the audible wave sensor and the ultrasonic sensor are directly fixed to the output end of the acoustic head.

Similarly, the probe of this embodiment also has the advantages of the probe of the embodiment 1, and will not be described again.

Example 3:

The present embodiment provides a seismic earthquake monitoring device, which includes the probe for seismic seismic monitoring provided by the foregoing embodiments, and further includes a main control unit and a wireless transmitting unit. The master unit is used to determine and select the optimal signal in the plurality of signal processing links, such as the signal with the best signal strength, and the selected signal is transmitted by the wireless transmitting unit, for example, to the ground sound monitoring center. In the implementation, the main control unit adopts the SoC chip of the MCU+DSP, and the wireless transmitting unit adopts the GPRS module or the TD-SCDMA module.

In a specific implementation, the main control unit and the wireless transmitting unit can be used as the ground base station, and the probe transmits the signal to the ground base station through the power supply and the signal cable. As shown in FIG. 6, the ground base station 70 includes the main control unit 701 and the wireless transmitting unit. 702. At this time, the plurality of signal processing links in the pre-processing circuit module of the probe output signals in parallel and are transmitted to the main control unit via the power supply and the signal cable. In order to have better anti-interference and longer transmission distance, the pre-processing circuit module and the ground base station use the RS-485 standard for communication; of course, in other embodiments, the RS-422 standard can also be used for communication.

In summary, the present application provides a low-cost, high-reliability, large-scale dense layout for the existing large-scale earthquake monitoring field, which can monitor the sound information of underground ground sounds for a long time. The monitoring data can be used for the process of large earthquakes. Scientific research, as well as forecasting.

The above description is only the preferred embodiment of the present application, and is only used to help the understanding of the application and is not intended to limit the application. Variations to the above-described embodiments may be made by those skilled in the art in light of the teachings herein.

Claims

Rights request

A probe for seismic earthquake monitoring, characterized in that it comprises:

a microphone for direct coupling with a point to be measured to capture a ground acoustic signal;

a plurality of sets of sensors for converting the ground acoustic signals into electrical signals, each set of sensors comprising at least two independent sensors, the frequency response ranges of the plurality of sets of sensors covering different acoustic acoustic wave bands;

a pre-processing circuit module for sequentially performing signal filtering, amplification, and analog-to-digital conversion on the electrical signal;

a power supply and signal cable for transmitting an output signal of the pre-processing circuit module and providing power to the pre-processing circuit module;

The power supply output terminal and the signal input end of the power supply and signal cable, the plurality of sets of sensors and the pre-processing circuit module are packaged and fixed to an output end of the sounding head by a package structure, and the power supply and signal cable The power supply input and the signal output extend out of the package structure.

2. The probe for seismic seismic monitoring according to claim 1, further comprising a sounding rod for transmitting said ground acoustic signal to said plurality of sets of sensors, each set of sensors comprising at least two independent Piezoelectric film sensors, each of which is attached to a surface of the sounding rod.

3. The probe for seismic seismic monitoring according to claim 2, wherein the package structure is further configured to package the sounding rod; the cross section of the sounding rod is a polygon, and the side of the polygon The number of strips is equal to the number of all of the piezoelectric thin film sensors.

4. The probe for seismic seismic monitoring according to claim 1, wherein the sounding rod is a solid rigid structure, and the sounding rod is provided with a connector at one end connected to the sounding head. The sounding head is a solid rigid structure, and the end of the sounding head for connecting with the sounding rod is provided with a connecting hole, and the connecting head is matched with the connecting hole.

5. The probe for seismic seismic monitoring according to claim 1, wherein a diameter of an input end of the sounding head is smaller than a diameter of an output end thereof; and the package structure outputs a power supply output end of the power supply and signal cable. And a signal input end, the plurality of sets of sensors and the pre-processing circuit module package are fixed in a cylindrical space of a diameter equal to an output end of the sounding head.

The probe for seismic seismic monitoring according to claim 1, wherein the plurality of sets of sensors comprise at least one set of infrasound sensors, at least one set of audible wave sensors, and at least one set of ultrasonic sensors.

The probe for seismic seismic monitoring according to any one of claims 1 to 6, wherein the pre-processing circuit module includes a plurality of signal processing links, and the plurality of signal processing links are independent of each other. Parallel and identical, for sequentially performing signal filtering, amplification, and analog-to-digital conversion output of the electrical signal in parallel; the number of the signal processing links and the plurality of sets of sensors The number of groups is the same, and a signal processing link is connected to a group of sensors. Each group of sensors adds the electrical signals converted by each sensor it contains to a corresponding signal processing link.

8. The probe for seismic seismic monitoring according to claim 7, wherein each of the plurality of sets of sensors is a backup of another set of sensors, and one of each set of sensors is the set of sensors. Backup of other sensors;

Each of the plurality of signal processing links is a backup of the other signal processing links.

A seismic surge monitoring device, comprising: the seismic seismic monitoring probe according to any one of claims 1-8, configured to select and process the preprocessed circuit module a master unit of the signal, and a wireless transmitting unit for transmitting the selected signal.

The apparatus for seismic earthquake monitoring according to claim 9, wherein the main control unit selects an output signal having the strongest signal from the pre-processing circuit module.