Vehicle-mounted micro-motion exploration device and method

Abstract

The invention discloses a vehicle-mounted micro-motion exploration device and method, the vehicle-mounted micro-motion exploration device comprises a tractor, a mechanical arm and an instrument panel, the tractor is provided with a data processing unit and an instrument placement bin, the mechanical arm is provided with a seismograph laying disc, and the seismograph laying disc is used for fixing seismographs into a specific formation; the instrument placing bin is used for storing an instrument tray and an auxiliary control system; according to the invention, a vehicle-mounted observation mode is adopted, and the array is directly set to be in a fixed and high-instrument-density mode, so that the processes of array design, instrument layout, instrument recovery and the like are omitted, the efficiency of micro-motion detection is remarkably improved, and the precision can be improved due to a large number of instruments.

Description

Technical Field

[0001] The invention belongs to the technical field of seismic exploration, and in particular relates to a vehicle-mounted micro-motion exploration device and method. Background Art

[0002] With the development of the world economy, the urbanization process is getting faster and faster. The urban shallow surface exploration technology, which is oriented to the needs of major projects such as urban planning, construction, monitoring, quality inspection and safety evaluation, has developed rapidly and gradually become one of the emerging frontier research fields in the geophysical community. In order to understand the status of space, geophysical methods can be used to detect underground space and realize the detection and assessment of hidden dangers under the foundation. Shallow artificial earthquake is a common technical method for engineering exploration.

[0003] In the prior art, the structure of the geological exploration excitation and observation system is: a heavy hammer structure is set up and a lifting device is used to drive the heavy hammer to rise and then fall to hit the road surface to form elastic wave excitation. Sensors and seismic sources form a longitudinal array along a straight line. After the seismic sources are excited one by one to complete data collection, the observation array is arranged in parallel.

[0004] The shortcomings of the existing technology are that the seismic source and the sensor need to be arranged separately, mostly manually, with slow acquisition speed, high labor intensity and long site occupation time, and the need to install an additional heavy hammer displacement drive device, which has a complex structure and needs further improvement. Summary of the invention

[0005] The present invention provides a vehicle-mounted micro-motion exploration device and method to solve the problems existing in the prior art.

[0006] To solve the above problems, the technical solution provided by the present invention is as follows:

[0007] The embodiment of the present invention provides a vehicle-mounted micro-seismic exploration device, comprising a tractor, a mechanical arm, an instrument tray and a remote control system, wherein the tractor is provided with a data processing unit and an instrument placement compartment, the mechanical arm is provided with a seismograph arrangement disk, and the seismograph arrangement disk is used to fix a seismograph array of a specific shape;

[0008] Among them, the instrument placement bin is used to store the instrument tray and the auxiliary control system, and the remote control system and the auxiliary control system are connected via WiFi or a mobile communication network; the data processing unit is used to collect and analyze the seismic wave signals of the seismograph array; the remote control system is used to receive data sent by the GPS positioning module and the seismograph array, and control the operation of the data processing unit and the seismograph array.

[0009] In a preferred embodiment of the present invention, a retractable canopy is provided on the carriage of the tractor.

[0010] In a preferred embodiment of the present invention, the tractor is connected to the disk storing the seismograph array via a rotating arm.

[0011] In a preferred embodiment of the present invention, the seismograph array is a circular array of seismic instruments that synchronously record micro-motion signals.

[0012] In a preferred embodiment of the present invention, the radius of the seismograph placement disk can be determined according to the size of the tractor, which can be 2.5 meters. An odd number of seismograph placement holes are arranged at equal angles on the two circles inside the seismograph placement disk, and the larger the number, the higher the accuracy. A seismograph placement hole is arranged at the center of the large circle inside the seismograph placement disk, and a seismograph is arranged in each seismograph placement hole.

[0013] In a preferred embodiment of the present invention, 13 seismograph placement holes are arranged at equal angles on two circles inside the seismograph layout disk.

[0014] In a preferred embodiment of the present invention, the seismograph uses a wireless router to communicate with the data processing unit to obtain the vibration data recorded by each instrument in real time. The data processing unit uses a spatial autocorrelation method SPAC to extract the dispersion curve, and obtains the pseudo-shear wave velocity based on the dispersion curve inversion or based on empirical relationships.

[0015] An embodiment of the present invention provides a vehicle-mounted micro-seismic exploration method, comprising the following steps: first, using the signal recorded by the seismograph to calculate the power spectrum; then, respectively calculating the spatial autocorrelation function between the seismograph at the measuring point and other surrounding stations, and obtaining the SPAC coefficient by directional averaging; secondly, using the formula to fit the zero-order Bessel function and the SPAC coefficient to obtain the phase velocity corresponding to different frequencies, thereby obtaining the Rayleigh wave phase velocity dispersion curve; finally, based on the dispersion curve interpolation or inversion, the one-dimensional apparent shear wave or shear wave velocity structure of the stratum below the measuring point is obtained, and the surface wave dispersion curve is extracted from the vertical component of the micro-seismic signal.

[0016] Compared with the prior art, the embodiments of the present invention provide a vehicle-mounted micro-motion exploration device and method, which have the following beneficial effects: (1) The present invention adopts a vehicle-mounted observation mode, directly sets the array to a fixed, high instrument density mode, and eliminates the processes of array design, instrument deployment, and instrument recovery, significantly improving the efficiency of micro-motion detection. More instruments can improve accuracy. It is particularly suitable for urban underground structure detection, and can make full use of the favorable conditions of fewer vehicles at night. The time for a single detection is also saved. Once the real-time processing result meets the accuracy requirement, the observation can be ended, and it is not necessary to wait until the usually required half an hour. (2) The data processing method of the present invention uses the spatial autocorrelation method SPAC to extract the dispersion curve, and then obtains the shear wave velocity through inversion or obtains the quasi-shear wave velocity through an empirical formula. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A schematic structural diagram of a vehicle-mounted micro-motion exploration device provided in an embodiment of the present application.

[0019] Figure 2 A schematic diagram of the layout of the seismograph disk of a vehicle-mounted micro-seismic exploration device provided in an embodiment of the present application.

[0020] Figure 3 A schematic diagram of a micro-motion observation array provided in an embodiment of the present application.

[0021] Figure 4 A spatial autocorrelation coefficient diagram provided in an embodiment of the present application.

[0022] Figures 5 to 10 A basic flow chart of SPAC method data processing provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0024] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a vehicle-mounted micro-motion exploration device, including a tractor 1, a mechanical arm 4, an instrument tray and a remote control system. The tractor 1 is provided with a data processing unit 2 and an instrument placement compartment 3, and the mechanical arm 4 is provided with a seismograph layout disc 5. The seismograph layout disc 5 is used to fix a seismograph array of a specific shape. The seismograph layout disc 5 is used to keep the instrument in a fixed formation. When the disc is lifted, the instrument can be stored and placed in the carriage; when the disc is lowered, the instrument is out of contact with the disc, and the observation is not affected by the disc. A retractable canopy 7 is provided on the carriage of the tractor 1 of this embodiment. The tractor 1 is connected to the disc storing the seismograph array through a rotating arm 6. The mechanical arm 4 can put down the seismograph layout disc 5, and after use, the seismograph layout disc 5 is rotated and retracted, and placed in the carriage.

[0025] Among them, the instrument placement compartment 3 is used to store the instrument tray and auxiliary control system, and the remote control system and the auxiliary control system are connected via WiFi or a mobile communication network; the data processing unit 2 is used to collect and analyze seismic wave signals from the seismograph array; the remote control system is used to receive data sent by the GPS positioning module and the seismograph array, and to control the operation of the data processing unit 2 and the seismograph array.

[0026] The seismograph array is a circular array of seismic instruments that synchronously record micro-motion signals. The radius of the seismograph arrangement disk can be determined according to the size of the tractor, which can be 2.5 meters. An odd number of seismograph placement holes are arranged at equal angles on the two circles inside the seismograph arrangement disk. The larger the number, the higher the accuracy. A seismograph placement hole is arranged at the center of the large circle inside the seismograph arrangement disk, and a seismograph is arranged in each seismograph placement hole. The seismograph is generally large in the middle and small above and below. Therefore, when the seismograph placement hole is lifted, the seismograph can be put away. When it is put down, the seismograph does not touch the seismograph placement hole, so that the instrument can be observed without being affected by the seismograph arrangement disk 5. Preferably, 13 seismograph placement holes are arranged at equal angles on the two circles inside the seismograph arrangement disk. Each seismograph placement hole in this embodiment is set to be hollowed out to store the seismograph. When the seismograph arrangement disk 5 is placed on the ground, it is ensured that each seismograph at the circumference and the center of the circle can fully contact the ground without touching the seismograph arrangement disk 5, so that the ground motion at various places can be detected.

[0027] The seismograph uses a wireless router to communicate with the data processing unit to obtain the vibration data recorded by each instrument in real time. The data processing unit uses the spatial autocorrelation method SPAC to extract the dispersion curve, and obtains the pseudo-short wave velocity based on the dispersion curve inversion or based on empirical relationships.

[0028] The micro-motion detection array of the present invention is made into a vehicle-mounted device set to a fixed, high-instrument density mode, eliminating the process of array design, instrument layout, instrument recovery, etc., significantly improving the efficiency of micro-motion detection, and more instruments can improve the accuracy. It is particularly suitable for urban underground structure detection, and can make full use of the favorable conditions of fewer vehicles at night to carry out operations. The time of a single detection is also saved. Once the real-time processing result meets the accuracy requirement, the observation can be ended, and it is not necessary to wait until the usual half an hour.

[0029] refer to Figures 5 to 10, an embodiment of the present invention further provides a vehicle-mounted microtremor exploration method, including the following steps: First, calculate the power spectrum using the signals recorded by the seismograph; then calculate the spatial autocorrelation function between the seismograph at the measurement point and other surrounding stations respectively, and obtain the SPAC coefficient through directional averaging; secondly, use the formula to fit the zero-order Bessel function and the SPAC coefficient to obtain the phase velocity corresponding to different frequencies, so as to obtain the Rayleigh wave phase velocity dispersion curve; finally, based on the dispersion curve, interpolate or invert to obtain the one-dimensional apparent shear wave or shear wave velocity structure of the formation below the measurement point, and extract the surface wave dispersion curve from the vertical component of the microtremor signal. Figure 5 It is a schematic diagram of the microtremor observation signal. Figure 6 It is a schematic diagram of calculating the power spectrum. Figure 7 It is a schematic diagram of calculating the correlation function. Figure 8 It is a schematic diagram of fitting the Bessel function to calculate the phase velocity. Fig. 9 It is a schematic diagram of obtaining the phase velocity dispersion curve. Fig.10 It is a schematic diagram of calculating the shear wave velocity structure.

[0030] The spatial autocorrelation method SPAC is a method for extracting the surface wave dispersion curve from the vertical component of the microtremor signal by arranging an array. The SPAC method was first proposed by Aki, mainly based on two assumptions: ① The microtremor conforms to a stationary random process in space and time; ② Among the different component waves contained in the microtremor, the fundamental surface wave is the main one.

[0031] The spectral polar coordinate form of the microtremor signal is:

[0032] In formula (1), ω and k form a functional relationship, ζ = r(cosθ, sinθ), k = k(cosφ, sinφ). Usually, the wave spectrum of the microtremor can be considered continuously differentiable with respect to frequency and propagation direction, so the above formula can be rewritten as:

[0033] E[丨dz(ω, φ)丨 2 = dH(ω, φ) = h(ω, φ)dωdφ (2).

[0034] In the formula, H(ω, φ) is the integral spectrum of X(t, r, θ) with respect to the azimuth, and h(ω, φ) is called the frequency-azimuth density.

[0035] As Figure 3 shown, assume that the spectral frequencies of the microtremor records at two points O(0, 0) and A(r, θ) on the circular array are respectively:

[0036]

[0037] In the formula, ω is the angular frequency, k is the wave number, φ is the incident angle of the microtremor signal, and ζ(ω, φ) is an orthogonal random process.

[0038] Then the spatial autocorrelation function S(r,θ) of points O and A is defined as:

[0039]

[0040] Where g(ω,r,θ) is the spatial covariance function and h(ω,φ) is the frequency-azimuth spectral density. Taking the azimuth average of the spatial covariance function g(ω,r,θ) yields:

[0041]

[0042] Where J0 is the zero-order Bessel function of the first kind.

[0043] Define ρ(ω, r) as the spatial autocorrelation coefficient of angular frequency ω:

[0044]

[0045] Substituting k = ω / c(ω), ω = 2πf (c(ω) is the Rayleigh wave phase velocity) into equation (7), we obtain:

[0046]

[0047] This formula shows that the Rayleigh wave phase velocity can be obtained by the first-kind zero-order Bessel function and the spatial autocorrelation coefficient. The corresponding spatial autocorrelation coefficient is Figure 4 shown.

[0048] Okada calculated the spatial autocorrelation coefficient in the frequency domain by Fourier transform, which effectively improved the calculation speed and accuracy[5]. The Fourier transform of points O(0,0) and A(r,θ) are expressed as SO(0,ω) and SA(r,ω) respectively, then the spatial autocorrelation coefficient of the two points in the frequency domain can be expressed as

[58] :

[0049]

[0050] In the formula, Re(·) represents the real part and * represents the complex conjugate. Substituting formula (9) into formula (8) we can get the Rayleigh wave phase velocity c(ω), and then get the phase velocity dispersion curve.

[0051] Although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A vehicle-mounted micro-motion exploration device, characterized in that: It includes a tractor, a mechanical arm, an instrument tray and a remote control system. The tractor is provided with a data processing unit and an instrument placement compartment. The mechanical arm is provided with a seismograph arrangement disk, and the seismograph arrangement disk is used to fix a seismograph array of a specific shape. Among them, the instrument placement bin is used to store the instrument tray and the auxiliary control system, and the remote control system and the auxiliary control system are connected via WiFi or a mobile communication network; the data processing unit is used to collect and analyze the seismic wave signals of the seismograph array; the remote control system is used to receive data sent by the GPS positioning module and the seismograph array, and control the operation of the data processing unit and the seismograph array.

2. A vehicle-mounted micro-motion exploration device according to claim 1, characterized in that: A retractable canopy is arranged on the carriage of the tractor.

3. A vehicle-mounted micro-motion exploration device according to claim 1, characterized in that: The tractor is connected to the disk storing the seismograph array via a rotating arm.

4. The vehicle-mounted micro-motion exploration device according to claim 1, characterized in that: The seismograph array is a circular array of seismic instruments that synchronously records micro-motion signals.

5. A vehicle-mounted micro-motion exploration device according to claim 4, characterized in that: The radius of the seismograph placement disk can be determined according to the size of the tractor, which can be 2.5 meters. An odd number of seismograph placement holes are arranged at equal angles on the two circles inside the seismograph placement disk. The larger the number, the higher the accuracy. A seismograph placement hole is arranged in the center of the large circle inside the seismograph placement disk, and a seismograph is arranged in each seismograph placement hole.

6. A vehicle-mounted micro-motion exploration device according to claim 5, characterized in that: Thirteen seismograph placement holes are arranged at equal angles on two circles inside the seismograph arrangement disk.

7. The vehicle-mounted micro-motion exploration device according to claim 5, characterized in that: The seismograph uses a wireless router to communicate with the data processing unit to obtain the vibration data recorded by each instrument in real time. The data processing unit uses the spatial autocorrelation method SPAC to extract the dispersion curve, and obtains the pseudo-short wave velocity based on the dispersion curve inversion or based on the empirical relationship.

8. A vehicle-mounted micro-motion exploration method, characterized in that: The following steps are involved: First, the power spectrum is calculated using the signal recorded by the seismograph. Then, the spatial autocorrelation function between the seismograph at the measuring point and other surrounding stations is calculated respectively, and the SPAC coefficient is obtained by directional averaging. Secondly, the zero-order Bessel function and the SPAC coefficient are fitted using the formula to obtain the phase velocity corresponding to different frequencies, thereby obtaining the Rayleigh wave phase velocity dispersion curve. Finally, the one-dimensional apparent shear wave or shear wave velocity structure of the stratum below the measuring point is obtained by interpolation or inversion based on the dispersion curve, and the surface wave dispersion curve is extracted from the vertical component of the micromotion signal.

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