Method and device for detecting undulating stratum in construction of shallow-buried power tunnel and storage medium
By setting up a three-component geophone array on the surface and inside the tunnel, and performing seismic data preprocessing, interferometry, and full waveform inversion, the accuracy problem of detecting undulating strata in shallow buried power tunnels in densely built urban environments was solved, achieving higher accuracy in underground structure simulation and geological prediction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGZHOU POWER SUPPLY BUREAU GUANGDONG POWER GRID CO LTD
- Filing Date
- 2023-11-15
- Publication Date
- 2026-06-09
AI Technical Summary
In densely built-up urban environments, existing seismic wave exploration technologies are insufficient to meet the accuracy requirements for detecting undulating strata in shallow-buried power tunnels. This is especially true in complex urban surface environments where traditional seismic exploration methods struggle to meet the demands for both observation space and accuracy.
A three-component geophone array was used to simultaneously collect environmental noise from the surface and inside the tunnel. Seismic data preprocessing, seismic interferometry, and full waveform inversion were performed, including linear superposition and amplitude normalization, to obtain the velocity model and geological profile of the surrounding rock above the power tunnel.
It improves the interpretability and accuracy of seismic data, reduces noise interference, enhances data quality and interpretation accuracy, and can more accurately infer the velocity model and geological conditions of the surrounding rock above power tunnels, adapting to the detection needs of densely built urban environments.
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Figure CN117572501B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of geological exploration technology for shallow buried power tunnels, and in particular to a method, device and storage medium for detecting undulating strata during the construction of shallow buried power tunnels. Background Technology
[0002] With the continuous expansion of infrastructure construction in my country, urban underground space has received increasing attention, leading to a surge in the construction of underground projects such as power tunnels and integrated utility tunnels. The construction of tunnels and other underground projects places higher demands on construction quality, efficiency, and safety. As urbanization intensifies, a large influx of people into cities is creating increasingly complex surface environments. Traditional excavation and drill-and-blast methods are no longer sufficient to meet the needs of urban development. Tunnel boring machines (TBMs), due to their high degree of mechanization and efficiency, are gradually replacing traditional excavation methods and are becoming increasingly widely used. Power tunnels are generally shallow and often located in densely populated areas. If proper tunnel support is not implemented based on the geological conditions above the excavated tunnel, collapses and other disasters can easily occur, affecting tunnel construction safety and the surrounding environment. Therefore, after tunnel excavation, it is necessary to promptly investigate the geological undulations above the tunnel and formulate appropriate support measures.
[0003] Seismic wave detection methods have been increasingly widely used in geological exploration, offering advantages such as high imaging accuracy and long detection range. Traditional seismic detection mainly includes active source seismic detection and passive source seismic detection, but these methods often struggle to meet the observation space requirements of increasingly complex urban surface environments. Inter-well seismic technology was introduced into oil and gas exploration in the 1970s, enabling efficient stratigraphic and geological structure detection, but it also suffers from insufficient lateral resolution. In 1973, Academician Galperin proposed vertical seismic profiling technology, which can obtain rich azimuth and shot-receiver distance information, effectively improving the longitudinal resolution of detection; however, the observation system using this method is difficult to adapt to urban environments.
[0004] In summary, the detection of undulating strata in shallow-buried power tunnels in densely built urban environments still suffers from the problem of low accuracy in seismic wave exploration. Summary of the Invention
[0005] The purpose of this application is to address at least one of the aforementioned technical deficiencies, particularly the low accuracy of seismic wave exploration in the prior art.
[0006] In a first aspect, this application provides a method for detecting undulating strata during the construction of shallow-buried power tunnels, the method comprising:
[0007] By simultaneously collecting environmental noise using a surface three-component geophone array pre-installed on the surface of the power tunnel and a tunnel interior three-component geophone array pre-installed inside the power tunnel, initial surface seismic records and initial tunnel interior seismic records are obtained.
[0008] Preprocessing is performed on the seismic data in the surface seismic record and the seismic data in the tunnel interior seismic record to obtain the target surface seismic record and the target tunnel interior seismic record;
[0009] Seismic interference is performed between the seismic data of each seismic record in the target surface seismic record and the seismic data of the first seismic record in the target surface seismic record to obtain the first virtual source shot set corresponding to the target surface seismic record; and seismic interference is performed between the seismic data of each seismic record in the target tunnel interior seismic record and the seismic data of the first seismic record in the target tunnel interior seismic record to obtain the second virtual source shot set corresponding to the seismic data inside the target tunnel.
[0010] The seismic data from the first virtual source shot set are linearly superimposed, and the seismic data from the second virtual source shot set are linearly superimposed. The seismic data obtained by linear superposition of the first and second virtual source shot sets are then subjected to amplitude normalization.
[0011] Full waveform inversion is performed on the seismic data after the concentrated amplitude normalization of the first virtual source shot and the seismic data after the concentrated amplitude normalization of the second virtual source shot to obtain the velocity model and geological profile of the surrounding rock above the power tunnel. Based on the velocity model and the geological profile, the grade of the surrounding rock above the power tunnel is predicted.
[0012] In one embodiment, the surface three-component geophone array is located within a predetermined range directly above the power tunnel;
[0013] In the array of three-component surface geophones, each three-component surface geophone is arranged in a straight line or randomly, and the spacing between each three-component surface geophone is a channel-changing distance.
[0014] In one embodiment, the three-component detector array inside the tunnel is attached to the wall, top, or sidewall of the power tunnel.
[0015] In one embodiment, the preprocessing includes mean and linear trend removal, data segmentation, instrument response removal, spectrum analysis and bandpass filtering, spectral whitening, and moving absolute averaging.
[0016] In one embodiment, the seismic interferometry employs a cross-correlation method, and the cross-correlation function is:
[0017]
[0018] In the formula, R2(f) and R1(f) represent the frequency domain representations of the two seismic records, respectively. Let R1(f) be the complex conjugate function. Let f be the phase difference between the two seismic records at frequency f.
[0019] In one embodiment, the seismic interferometry employs a mutual coherence method, and the mutual coherence function is:
[0020]
[0021] In the formula, u(X) A ,ω) represents X A Frequency domain seismic records received at a point, u(X) B ,ω) represents X B Frequency domain seismic records received at the point; * indicates taking the conjugate.
[0022] In one embodiment, the full waveform inversion uses LBFGS as the optimization method, and the objective function of the full waveform inversion is:
[0023]
[0024] In the formula, Let m be the objective function, S be the seismic source, R be the geophone, u(m) be the forward-modeled time-domain seismic wave field emitted by the seismic source S and received by the geophone R when the model parameter is m, and d be the actual observation data at the same time and spatial location.
[0025] Secondly, this application provides a device for detecting undulating strata during shallow-buried power tunnel construction, the device comprising:
[0026] The initial seismic record acquisition module is used to simultaneously collect environmental noise using a surface three-component geophone array pre-installed on the surface of the power tunnel and a tunnel interior three-component geophone array pre-installed inside the power tunnel, so as to obtain the initial surface seismic record and the initial tunnel interior seismic record.
[0027] The target seismic record acquisition module is used to preprocess the seismic data in the surface seismic record and the seismic data in the tunnel interior seismic record to obtain the target surface seismic record and the target tunnel interior seismic record.
[0028] The virtual source shot set acquisition module is used to perform seismic interference on the seismic data of each seismic record in the target surface seismic record and the seismic data of the first seismic record in the target surface seismic record to obtain the first virtual source shot set corresponding to the target surface seismic record, and to perform seismic interference on the seismic data of each seismic record in the target tunnel interior seismic record and the seismic data of the first seismic record in the target tunnel interior seismic record to obtain the second virtual source shot set corresponding to the seismic data inside the target tunnel.
[0029] The seismic data processing module is used to linearly superimpose the seismic data from the first virtual source shot set and the seismic data from the second virtual source shot set, and to perform amplitude normalization processing on the linearly superimposed seismic data from the first virtual source shot set and the linearly superimposed seismic data from the second virtual source shot set.
[0030] The full waveform inversion module is used to perform full waveform inversion on the seismic data after the concentrated amplitude normalization processing of the first virtual source shot and the seismic data after the concentrated amplitude normalization processing of the second virtual source shot, respectively, to obtain the velocity model and geological profile of the surrounding rock above the power tunnel, so as to predict the grade of the surrounding rock above the power tunnel based on the velocity model and the geological profile.
[0031] Thirdly, this application provides a storage medium storing computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the steps of the shallow buried power tunnel construction undulating strata detection method described in any of the above embodiments.
[0032] Fourthly, this application provides a computer device, including: one or more processors, and a memory;
[0033] The memory stores computer-readable instructions, which, when executed by the one or more processors, perform the steps of the shallow buried power tunnel construction undulating strata detection method described in any of the above embodiments.
[0034] As can be seen from the above technical solutions, the embodiments of this application have the following advantages:
[0035] In the method, apparatus, and storage medium for detecting undulating strata during shallow-buried power tunnel construction provided in this application, environmental noise is simultaneously collected using a surface three-component geophone array pre-installed on the surface of the power tunnel and a tunnel interior three-component geophone array pre-installed inside the power tunnel to obtain initial surface seismic records and initial tunnel interior seismic records. The seismic data in the surface seismic records and the seismic data in the tunnel interior seismic records are preprocessed to obtain target surface seismic records and target tunnel interior seismic records. Seismic interferometry is performed between the seismic data of each seismic record in the target surface seismic records and the seismic data of the first seismic record in the target surface seismic records to obtain the first virtual source shot gather corresponding to the target surface seismic records. Furthermore, the seismic data of each seismic record in the target tunnel interior seismic records are preprocessed. Seismic data is interferometrically analyzed with the seismic data of the first seismic record in the seismic record inside the target tunnel to obtain the second virtual source shot set corresponding to the seismic data inside the target tunnel. The seismic data in the first virtual source shot set and the seismic data in the second virtual source shot set are linearly superimposed, and the amplitude of the linearly superimposed seismic data in the first and second virtual source shot sets is normalized. Full waveform inversion is performed on the amplitude-normalized seismic data in the first and second virtual source shot sets respectively to obtain the velocity model and geological profile of the surrounding rock above the power tunnel, so as to predict the grade of the surrounding rock above the power tunnel based on the velocity model and the geological profile. By deploying a three-component geophone array both on the surface and inside the power tunnel, the system fully utilizes environmental space, reduces the need for surface detection space, and solves the problem of limited seismic observation system deployment in densely built-up urban areas. Directly utilizing background noise for detection reduces the impact of noise interference, addressing the issue of strong noise interference in urban environments. Multi-layer data acquisition: By setting up geophone arrays on the surface and inside the tunnel, multi-level and multi-angle seismic data acquisition is achieved, improving the comprehensiveness and reliability of seismic data acquisition. Seismic interferometry processing yields virtual source shot gathers for the target surface and inside the tunnel, thus better simulating underground structures and improving the interpretability and accuracy of seismic data. Linear superposition and amplitude normalization processing help reduce noise, enhance signals, and ensure data consistency and comparability, thereby improving data quality and the accuracy of interpretation. Full waveform inversion processing allows for more accurate inference of the surrounding rock velocity model and geological profile above the power tunnel, providing a more reliable basis for geological condition prediction. Thus, the accuracy of undulating strata detection in shallow-buried power tunnels in densely built-up urban environments can be improved. Attached Figure Description
[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0037] Figure 1 A schematic flowchart illustrating the method for detecting undulating strata during shallow-buried power tunnel construction provided in this application embodiment;
[0038] Figure 2 A schematic diagram of the undulating strata detection and observation system for shallow buried power tunnel construction provided in this application embodiment;
[0039] Figure 3 This is a schematic diagram illustrating the working status of undulating strata detection during the construction of a shallow-buried power tunnel, provided in an embodiment of this application.
[0040] Figure 4 A schematic diagram of the process for detecting undulating strata during shallow-buried power tunnel construction provided in this application embodiment;
[0041] Figure 5 This is a schematic diagram of the internal structure of a computer device provided in an embodiment of this application. Detailed Implementation
[0042] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0043] In one embodiment, this application provides a method for detecting undulating strata during the construction of shallow-buried power tunnels. The following embodiments illustrate this method using a computer device as an example. It is understood that the computer device can be any device with data processing capabilities, including but not limited to a single server, server cluster, personal laptop, desktop computer, etc. Seismic data processing instruments can also be used in this application. Figure 1 As shown, this application provides a method for detecting undulating strata during the construction of shallow buried power tunnels, the method comprising:
[0044] S101: Using a surface three-component geophone array pre-installed on the surface of the power tunnel and a tunnel interior three-component geophone array pre-installed inside the power tunnel, environmental noise is collected synchronously to obtain initial surface seismic records and initial tunnel interior seismic records.
[0045] In this step, environmental noise is simultaneously acquired using a surface three-component geophone array pre-installed on the surface of the power tunnel and a tunnel interior three-component geophone array pre-installed inside the power tunnel. This yields initial surface seismic records and initial tunnel interior seismic records. These records include the impact of environmental noise on seismic waves propagating at the surface and inside the tunnel. The surface three-component geophone array acquires information about seismic waves propagating from underground to the surface, while the tunnel interior three-component geophone array acquires information about seismic waves propagating inside the tunnel. By simultaneously acquiring environmental noise, noise characteristics at different locations can be obtained for subsequent data processing and analysis.
[0046] Furthermore, each geophone can be time-synchronized via GPS signals. The surface three-component geophone array automatically receives GPS signals, while the tunnel three-component geophone array is time-synchronized via a time synchronization host and fiber optic cable. Both the surface and tunnel three-component geophone arrays can simultaneously acquire multi-component seismic data.
[0047] S102: Preprocess the seismic data in the surface seismic record and the seismic data in the tunnel interior seismic record to obtain the target surface seismic record and the target tunnel interior seismic record.
[0048] In this step, seismic data from surface seismic records and tunnel interior seismic records are preprocessed to obtain the target surface seismic record and the target tunnel interior seismic record. In one example, preprocessing may include denoising, filtering, time-domain transformation, and correction. Denoising can use appropriate digital signal processing algorithms, such as wavelet denoising or mean filtering, to remove environmental noise and other interference from the seismic records to highlight subsurface structure information. Low-pass and high-pass filtering is applied to the seismic records to remove high-frequency and low-frequency noise, making the seismic data clearer and easier to interpret. The seismic records can be transformed from the time domain to the frequency domain using methods such as Fourier transform, which helps to analyze the spectral characteristics of seismic waves and provides more information for subsequent geological structure analysis. Time correction is applied to the seismic records to ensure that data acquired by different detectors are aligned, thereby making the imaging of subsurface structures more accurate.
[0049] S103: Perform seismic interferometry on the seismic data of each seismic record in the target surface seismic record and the seismic data of the first seismic record in the target surface seismic record to obtain the first virtual source shot set corresponding to the target surface seismic record; and perform seismic interferometry on the seismic data of each seismic record in the target tunnel interior seismic record and the seismic data of the first seismic record in the target tunnel interior seismic record to obtain the second virtual source shot set corresponding to the seismic data inside the target tunnel.
[0050] Among them, seismic interferometry is a method based on the wave equation that enhances the imaging of underground structures by adjusting the phase and amplitude of multiple seismic records to achieve virtual resonance points (virtual sources).
[0051] In this step, the phase and amplitude of each seismic record in the target surface seismic record are adjusted to align with the first seismic record in terms of time and phase. The adjusted surface seismic records are then superimposed to obtain the first virtual source shot gather of the target surface seismic record. Similarly, the phase and amplitude of each seismic record in the target tunnel interior seismic record are adjusted to align with the first seismic record in terms of time and phase. The adjusted tunnel interior seismic records are then superimposed to obtain the second virtual source shot gather of the target tunnel interior seismic data.
[0052] S104: Linearly superimpose the seismic data from the first virtual source shot set and the seismic data from the second virtual source shot set, and then perform amplitude normalization processing on the linearly superimposed seismic data from the first and second virtual source shot sets.
[0053] In this step, each seismic record from the first virtual source shot set is summed point-by-point to obtain linearly stacked seismic data. Similarly, each seismic record from the second virtual source shot set is summed point-by-point to obtain linearly stacked seismic data. Amplitude normalization is then performed on both the linearly stacked seismic data from the first and second virtual source shot sets. Amplitude normalization is achieved by dividing each data point by the maximum absolute value, thus ensuring that the two datasets have similar amplitude ranges.
[0054] S105: Perform full waveform inversion on the seismic data after the concentrated amplitude normalization of the first virtual source shot and the seismic data after the concentrated amplitude normalization of the second virtual source shot to obtain the velocity model and geological profile of the surrounding rock above the power tunnel, so as to predict the grade of the surrounding rock above the power tunnel based on the velocity model and the geological profile.
[0055] In this step, full-waveform inversion is a commonly used seismic data processing method that can invert the velocity model of the subsurface medium by matching observed seismic data with simulated seismic data. In one example, based on existing geological information and prior knowledge, an initial velocity model is constructed, which will be used as the starting point for full-waveform inversion. Using the initial velocity model, simulated seismic data is generated through numerical simulation methods (such as the finite difference method or the finite element method). The parameter settings of the simulated seismic data should be consistent with those of the observed seismic data. The observed and simulated seismic data are compared, and an objective function, such as the least squares error function, is defined as the optimization objective for full-waveform inversion. The objective function measures the difference between the observed and simulated data. The initial velocity model is adjusted using optimization algorithms (such as gradient descent, conjugate gradient, etc.) to minimize the objective function. The velocity model is iteratively updated until the convergence condition is met or the preset inversion objective is satisfied. The velocity model obtained from each inversion can be evaluated through comparison with observed data, seismic response analysis, and other methods. Based on the evaluation results, the inversion parameters can be further optimized or the inversion strategy can be adjusted. After obtaining the velocity model that conforms to the observation data, the velocity model and geological profile of the surrounding rock above the power tunnel can be generated based on the velocity model and the existing geological information.
[0056] Velocity models provide information about the physical properties of the subsurface medium, while geological profiles reveal the structural characteristics of the surrounding rock above the tunnel. Using both velocity models and geological profiles, the grade of the surrounding rock above the tunnel can be predicted. Based on different regions in the velocity model, characteristics such as lithology, density, and strength of the surrounding rock can be inferred, and variations in the surrounding rock above the tunnel can be depicted based on the geological profiles.
[0057] In the above embodiments, environmental noise is synchronously collected using a surface three-component geophone array pre-installed on the surface of the power tunnel and a tunnel interior three-component geophone array pre-installed inside the power tunnel to obtain initial surface seismic records and initial tunnel interior seismic records. The seismic data in the surface seismic records and the seismic data in the tunnel interior seismic records are preprocessed to obtain target surface seismic records and target tunnel interior seismic records. Seismic interferometry is performed between the seismic data of each seismic record in the target surface seismic records and the seismic data of the first seismic record in the target surface seismic records to obtain the first virtual source shot set corresponding to the target surface seismic records. Seismic data is also interferometry between the seismic data of each seismic record in the target tunnel interior seismic records and the seismic data of the first seismic record in the target tunnel interior seismic records. Seismic data from the first seismic record in the seismic log are subjected to seismic interferometry to obtain the second virtual source shot set corresponding to the seismic data inside the target tunnel. The seismic data from the first virtual source shot set and the seismic data from the second virtual source shot set are linearly superimposed, and the amplitude of the linearly superimposed seismic data from the first and second virtual source shot sets is normalized. Full waveform inversion is performed on the amplitude-normalized seismic data from the first and second virtual source shot sets respectively to obtain the velocity model and geological profile of the surrounding rock above the power tunnel. Based on the velocity model and the geological profile, the grade of the surrounding rock above the power tunnel is predicted. By deploying a three-component geophone array both on the surface and inside the power tunnel, the system fully utilizes environmental space, reduces the need for surface detection space, and solves the problem of limited seismic observation system deployment in densely built-up urban areas. Directly utilizing background noise for detection reduces the impact of noise interference, addressing the issue of strong noise interference in urban environments. Multi-layer data acquisition: By setting up geophone arrays on the surface and inside the tunnel, multi-level and multi-angle seismic data acquisition is achieved, improving the comprehensiveness and reliability of seismic data acquisition. Through seismic interferometry, virtual source shot gathers are obtained for the target surface and inside the tunnel, thus better simulating underground structures and improving the interpretability and accuracy of seismic data. Linear superposition and amplitude normalization processing help reduce noise, enhance signals, and ensure data consistency and comparability, thereby improving data quality and the accuracy of interpretation. Through full waveform inversion processing, the velocity model and geological profile of the surrounding rock above the power tunnel can be more accurately inferred, providing a more reliable basis for geological condition prediction. Thus, the accuracy of undulating strata detection in shallow-buried power tunnels in densely built-up urban environments can be improved.
[0058] In one embodiment, the surface three-component geophone array is located within a predetermined range directly above the power tunnel;
[0059] In the array of three-component surface geophones, each three-component surface geophone is arranged in a straight line or randomly, and the spacing between each three-component surface geophone is a channel-changing distance.
[0060] Specifically, a surface three-component geophone array is located within a predetermined area directly above the power tunnel. These geophones are arranged either linearly or randomly, with variable spacing. This arrangement allows for the collection of seismic data, enabling full waveform inversion to infer the velocity model and geological structure of the surrounding rock above the power tunnel. In seismic exploration, surface three-component geophones record the vibrations of seismic waves propagating underground; this vibration data can be used to infer the properties of the subsurface medium. The linearly or randomly arranged surface three-component geophones effectively cover the target area, providing abundant seismic data and facilitating the acquisition of more comprehensive subsurface information. It is understood that the surface three-component geophone array can be located directly above the power tunnel.
[0061] In this embodiment, detectors arranged in a straight line or randomly can effectively cover the target area, providing more comprehensive seismic data and helping to acquire richer subsurface information. Variable spacing can increase the flexibility and diversity of the arrangement, helping to adapt to data acquisition needs under different geological conditions, thereby better reflecting the characteristics of the subsurface medium. More comprehensive and diverse seismic data can provide more information for the interpretation and analysis of the subsurface medium, helping to accurately infer the velocity model and geological structure of the surrounding rock above the power tunnel.
[0062] In one embodiment, the three-component detector array inside the tunnel is attached to the wall, top, or sidewall of the power tunnel.
[0063] Specifically, a common arrangement is to attach a three-component geophone array inside the tunnel to the wall, top, or sidewall of the power tunnel. This method allows for the monitoring and recording of seismic waves inside the tunnel, providing information about the properties of the subsurface medium and crucial data support for tunnel construction and understanding of the surrounding geological environment.
[0064] In this embodiment, by installing geophones on the tunnel wall, top, or sidewall, the propagation of seismic waves near the tunnel can be monitored in real time, helping to understand the changes and characteristics of the geological environment around the tunnel. Geophones arranged inside the tunnel can more accurately collect seismic data directly related to the geology around the tunnel. Placing geophones in different locations inside the tunnel can optimize the layout of seismic data acquisition, obtain comprehensive and three-dimensional seismic data, and facilitate a complete understanding of the underground structure.
[0065] In one embodiment, the preprocessing includes mean and linear trend removal, data segmentation, instrument response removal, spectrum analysis and bandpass filtering, spectral whitening, and moving absolute averaging.
[0066] Specifically, mean removal and delinearization refer to removing the DC component from the signal, i.e., mean removal. Delinearization aims to eliminate the "zero-point drift" problem that occurs after prolonged use of springs; methods include Hilbert-Huang transform and trend fitting. Data segmentation involves dividing the acquired seismic data into segments based on time intervals, with a 75% overlap between adjacent segments. Subsequent processing treats each time interval as a group of data. In instrument response removal, different broadband seismic stations from different manufacturers may record different physical quantities, such as displacement, velocity, and acceleration of particle vibrations. Instrument response removal involves normalizing the physical quantities recorded by different seismic stations, based on the instrument model, after obtaining a series of seismic records. In spectrum analysis and bandpass filtering, the frequency range of interest varies with exploration depth. Bandpass filtering can retain useful signals within a specific frequency range, improving the signal-to-noise ratio. Common methods include Butterworth filtering. Spectral whitening aims to remove energy peaks at certain frequencies, thereby broadening the spectrum and reducing the influence of certain frequency bands. The moving absolute average is a time-domain normalization method that can be used to suppress the influence of non-stationary random signals.
[0067] In one embodiment, the seismic interferometry employs a cross-correlation method, and the cross-correlation function is:
[0068]
[0069] In the formula, R2(f) and R1(f) represent the frequency domain representations of the two seismic records, respectively. Let R1(f) be the complex conjugate function. Let f be the phase difference between the two seismic records at frequency f.
[0070] Specifically, seismic interferometry using cross-correlation can improve the resolution of subsurface media, which helps to detect subsurface structures and anomalies and reconstruct subsurface velocity models.
[0071] In one embodiment, the seismic interferometry employs a mutual coherence method, and the mutual coherence function is:
[0072]
[0073] In the formula, u(X) A ,ω) represents X A Frequency domain seismic records received at a point, u(X) B ,ω) represents XB Frequency domain seismic records received at the point; * indicates taking the conjugate.
[0074] Specifically, by processing seismic data through mutual coherence, the clarity of seismic signals can be improved, thereby enabling more accurate identification of the characteristics of underground structures.
[0075] In one embodiment, the full waveform inversion uses LBFGS as the optimization method, and the objective function of the full waveform inversion is:
[0076]
[0077] In the formula, Let m be the objective function, S be the seismic source, R be the geophone, u(m) be the forward-modeled time-domain seismic wave field emitted by the seismic source S and received by the geophone R when the model parameter is m, and d be the actual observation data at the same time and spatial location.
[0078] Specifically, the forward modeling algorithm in the full waveform inversion process can employ either acoustic forward modeling or elastic wave forward modeling. Both surface and underground geophones perform full waveform inversion simultaneously. LBFGS, a commonly used numerical optimization algorithm (Limited-memory Broyden-Fletcher-Goldfarb-Shanno), is a variant of the quasi-Newton method, primarily used to solve unconstrained nonlinear optimization problems. Employing LBFGS as the optimization method in full waveform inversion can improve the accuracy of the model and the resolution of underground structures.
[0079] To facilitate understanding of the scheme in this application, a specific example is provided below for illustration. For example... Figure 2 and Figure 3 As shown in the example, the method for detecting undulating strata during the construction of shallow buried power tunnels is as follows:
[0080] like Figure 2 The diagram shows a schematic of a ground undulating stratum detection and observation system for shallow-buried power tunnel construction. Figure 3 The diagram shows the working status of undulating strata detection during the construction of a shallow buried power tunnel.
[0081] like Figure 2 As shown, the shallow buried power tunnel construction undulating strata detection and observation system mainly includes a surface three-component geophone array 1, an in-tunnel three-component geophone array 2, a seismic data processing instrument system 3, and a time synchronization system 4.
[0082] like Figure 2 and Figure 3As shown in the diagram, in a typical implementation, the power tunnel passes under a densely populated urban area. The surrounding rock above the tunnel is undulating, and the geological conditions are complex, requiring timely geological investigation. The surface structures in the detection area are complex, limiting the available observation space. Based on the actual surface conditions, a three-component geophone array 1 is deployed above the tunnel, located directly above or within a certain range above the tunnel, to receive background noise propagating from the surface. A three-component geophone array 2 is deployed inside the tunnel, with the geophones fixed to the tunnel sidewalls or roof using adhesive bonding. A time synchronization system 4 is installed on the surface and connected to the first three-component geophone inside the tunnel via fiber optic cable. Time synchronization between the remaining three-component geophones inside the tunnel is achieved wirelessly. The surface three-component geophones are connected to the time synchronization host wirelessly or directly to a GPS signal. During data acquisition, data collected from the surface and inside the tunnel is transmitted in real-time to the seismic data processing instrument system 3, where it is processed in real-time to obtain the stratigraphic structure of the surrounding rock above the tunnel.
[0083] In different implementations, the surface three-component geophone array is located on the surface of the excavated section of the tunnel and consists of multiple three-component geophones. The number of geophones and the arrangement of the observation system are adjusted according to the actual detection requirements and engineering environment. The in-tunnel three-component geophones are located on the sidewalls or top of the excavated section of the tunnel. The position and number of the geophones are adjusted according to the actual environment. Before data acquisition, time synchronization is first performed using a time synchronization system.
[0084] During data acquisition, surface and tunnel geophones collect data simultaneously and transmit it in real time. The acquired seismic records are then transmitted to the seismic data instrument processing system, which automatically processes the data to obtain the stratigraphic structure of the surrounding rock above the excavated section of the tunnel.
[0085] The data processing flow for the method of detecting undulating strata in shallow buried power tunnel construction includes three parts: data preprocessing, extraction of virtual source shot collection, and full waveform inversion.
[0086] First, before conducting the exploration, the observation system was deployed. In this embodiment, 12 three-component geophones were deployed both on the surface and inside the tunnel. The surface geophones were arranged according to the space between surface buildings, while the tunnel geophones were attached to the tunnel sidewalls. After the deployment of the three-component geophones was completed, the geophones and the time synchronization system were activated to perform time synchronization. After time synchronization was completed, background noise was collected from the surface and inside the tunnel. The data collected by each three-component geophone was transmitted in real time to the seismic data processing instrument system for data processing.
[0087] The following describes the undulating strata detection device for shallow buried power tunnel construction provided in the embodiments of this application. The undulating strata detection device for shallow buried power tunnel construction described below can be referred to in correspondence with the undulating strata detection method for shallow buried power tunnel construction described above. Figure 4 As shown, this application provides a device for detecting undulating strata during shallow-buried power tunnel construction, the device comprising:
[0088] The initial seismic record acquisition module 201 is used to synchronously collect environmental noise using a surface three-component geophone array pre-set on the surface of the power tunnel and a tunnel interior three-component geophone array pre-set inside the power tunnel, so as to obtain the initial surface seismic record and the initial tunnel interior seismic record.
[0089] The target seismic record acquisition module 202 is used to preprocess the seismic data in the surface seismic record and the seismic data in the tunnel internal seismic record to obtain the target surface seismic record and the target tunnel internal seismic record.
[0090] The virtual source shot set acquisition module 203 is used to perform seismic interference on the seismic data of each seismic record in the target surface seismic record and the seismic data of the first seismic record in the target surface seismic record to obtain the first virtual source shot set corresponding to the target surface seismic record, and to perform seismic interference on the seismic data of each seismic record in the target tunnel interior seismic record and the seismic data of the first seismic record in the target tunnel interior seismic record to obtain the second virtual source shot set corresponding to the seismic data inside the target tunnel.
[0091] The seismic data processing module 204 is used to linearly superimpose the seismic data from the first virtual source shot set and the seismic data from the second virtual source shot set, and to perform amplitude normalization processing on the linearly superimposed seismic data from the first virtual source shot set and the linearly superimposed seismic data from the second virtual source shot set.
[0092] The full waveform inversion module 205 is used to perform full waveform inversion on the seismic data after the concentrated amplitude normalization processing of the first virtual source shot and the seismic data after the concentrated amplitude normalization processing of the second virtual source shot, respectively, to obtain the velocity model and geological profile of the surrounding rock above the power tunnel, so as to predict the grade of the surrounding rock above the power tunnel based on the velocity model and the geological profile.
[0093] In one embodiment, the surface three-component geophone array is located within a predetermined range directly above the power tunnel;
[0094] In the array of three-component surface geophones, each three-component surface geophone is arranged in a straight line or randomly, and the spacing between each three-component surface geophone is a channel-changing distance.
[0095] In one embodiment, the three-component detector array inside the tunnel is attached to the wall, top, or sidewall of the power tunnel.
[0096] In one embodiment, the preprocessing includes mean and linear trend removal, data segmentation, instrument response removal, spectrum analysis and bandpass filtering, spectral whitening, and moving absolute averaging.
[0097] In one embodiment, the seismic interferometry employs a cross-correlation method, and the cross-correlation function is:
[0098]
[0099] In the formula, R2(f) and R1(f) represent the frequency domain representations of the two seismic records, respectively. Let R1(f) be the complex conjugate function. Let f be the phase difference between the two seismic records at frequency f.
[0100] In one embodiment, the seismic interferometry employs a mutual coherence method, and the mutual coherence function is:
[0101]
[0102] In the formula, u(X) A ,ω) represents X A Frequency domain seismic records received at a point, u(X) B ,ω) represents X B Frequency domain seismic records received at the point; * indicates taking the conjugate.
[0103] In one embodiment, the full waveform inversion uses LBFGS as the optimization method, and the objective function of the full waveform inversion is:
[0104]
[0105] In the formula, Let m be the objective function, S be the seismic source, R be the geophone, u(m) be the forward-modeled time-domain seismic wave field emitted by the seismic source S and received by the geophone R when the model parameter is m, and d be the actual observation data at the same time and spatial location.
[0106] In one embodiment, this application also provides a storage medium storing computer-readable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the shallow buried power tunnel construction undulating strata detection method as described in any of the above embodiments.
[0107] In one embodiment, this application also provides a computer device storing computer-readable instructions that, when executed by one or more processors, cause the one or more processors to perform the steps of the shallow buried power tunnel construction undulating strata detection method as described in any of the above embodiments.
[0108] Indicatively, such as Figure 5 As shown, Figure 5 This is a schematic diagram of the internal structure of a computer device 300 provided in an embodiment of this application. The computer device 300 can be provided as a server. (Refer to...) Figure 5 The computer device 300 includes a processing component 302, which further includes one or more processors, and memory resources represented by memory 301 for storing instructions, such as application programs, that can be executed by the processing component 302. The application programs stored in memory 301 may include one or more modules, each corresponding to a set of instructions. Furthermore, the processing component 302 is configured to execute instructions to perform the shallow-buried power tunnel construction undulating strata detection method of any of the above embodiments.
[0109] The computer device 300 may also include a power supply component 303 configured to perform power management of the computer device 300, a wired or wireless network interface 304 configured to connect the computer device 300 to a network, and an input / output (I / O) interface 305. The computer device 300 may operate on an operating system stored in memory 301, such as Windows Server™, Mac OS X™, Unix™, Linux™, Free BSD™, or similar.
[0110] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.
[0111] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this document, "a," "an," "the," "the," and "its" may also include plural forms unless the context clearly indicates otherwise. "Multiple" refers to at least two, such as 2, 3, 5, or 8, etc. "And / or" includes any and all combinations of the related listed items.
[0112] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.
[0113] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for detecting undulating strata during the construction of shallow-buried power tunnels, characterized in that, The method includes: By simultaneously collecting environmental noise using a surface three-component geophone array pre-installed on the surface of the power tunnel and a tunnel interior three-component geophone array pre-installed inside the power tunnel, initial surface seismic records and initial tunnel interior seismic records are obtained. Preprocessing is performed on the seismic data in the surface seismic record and the seismic data in the tunnel interior seismic record to obtain the target surface seismic record and the target tunnel interior seismic record; Seismic interference is performed between the seismic data of each seismic record in the target surface seismic record and the seismic data of the first seismic record in the target surface seismic record to obtain the first virtual source shot set corresponding to the target surface seismic record; and seismic interference is performed between the seismic data of each seismic record in the target tunnel interior seismic record and the seismic data of the first seismic record in the target tunnel interior seismic record to obtain the second virtual source shot set corresponding to the seismic data inside the target tunnel. The seismic data from the first virtual source shot set are linearly superimposed, and the seismic data from the second virtual source shot set are linearly superimposed. The seismic data obtained by linear superposition of the first and second virtual source shot sets are then subjected to amplitude normalization. Full waveform inversion is performed on the seismic data after the concentrated amplitude normalization of the first virtual source shot and the seismic data after the concentrated amplitude normalization of the second virtual source shot to obtain the velocity model and geological profile of the surrounding rock above the power tunnel. Based on the velocity model and the geological profile, the grade of the surrounding rock above the power tunnel can be predicted.
2. The method for detecting undulating strata during shallow-buried power tunnel construction according to claim 1, characterized in that, The surface three-component geophone array is located within a predetermined range directly above the power tunnel; In the array of three-component surface geophones, each three-component surface geophone is arranged in a straight line or randomly, and the spacing between each three-component surface geophone is a channel-changing distance.
3. The method for detecting undulating strata during shallow-buried power tunnel construction according to claim 1, characterized in that, The three-component detector array inside the tunnel is attached to the wall, top, or side wall of the power tunnel.
4. The method for detecting undulating strata during shallow-buried power tunnel construction according to claim 1, characterized in that, The preprocessing includes mean and linear trend removal, data segmentation, instrument response removal, spectrum analysis and bandpass filtering, spectral whitening, and moving absolute averaging.
5. The method for detecting undulating strata during shallow-buried power tunnel construction according to claim 1, characterized in that, The seismic interferometry employs a cross-correlation method, and the cross-correlation function is: In the formula, R2(f) and R1(f) represent the frequency domain representations of the two seismic records, respectively. Let R1(f) be the complex conjugate function. Let f be the phase difference between the two seismic records at frequency f.
6. The method for detecting undulating strata during shallow-buried power tunnel construction according to claim 1, characterized in that, The seismic interferometry employs the mutual coherence method, and the mutual coherence function is: In the formula, u(X) A ,ω) represents X A Frequency domain seismic records received at a point, u(X) B ,ω) represents X B Frequency domain seismic records received at the point; * indicates taking the conjugate.
7. The method for detecting undulating strata during shallow-buried power tunnel construction according to claim 1, characterized in that, The full waveform inversion uses LBFGS as the optimization method, and the objective function of the full waveform inversion is: In the formula, Let m be the objective function, S be the seismic source, R be the geophone, u(m) be the forward-modeled time-domain seismic wave field emitted by the seismic source S and received by the geophone R when the model parameter is m, and d be the actual observation data at the same time and spatial location.
8. A device for detecting undulating strata during shallow-buried power tunnel construction, characterized in that, The device includes: The initial seismic record acquisition module is used to synchronously collect environmental noise using a surface three-component geophone array pre-set on the surface of the power tunnel and a tunnel interior three-component geophone array pre-set inside the power tunnel, so as to obtain the initial surface seismic record and the initial tunnel interior seismic record. The target seismic record acquisition module is used to preprocess the seismic data in the surface seismic record and the seismic data in the tunnel interior seismic record to obtain the target surface seismic record and the target tunnel interior seismic record. The virtual source shot set acquisition module is used to perform seismic interference on the seismic data of each seismic record in the target surface seismic record and the seismic data of the first seismic record in the target surface seismic record to obtain the first virtual source shot set corresponding to the target surface seismic record, and to perform seismic interference on the seismic data of each seismic record in the target tunnel interior seismic record and the seismic data of the first seismic record in the target tunnel interior seismic record to obtain the second virtual source shot set corresponding to the seismic data inside the target tunnel. The seismic data processing module is used to linearly superimpose the seismic data from the first virtual source shot set and the seismic data from the second virtual source shot set, and to perform amplitude normalization processing on the linearly superimposed seismic data from the first virtual source shot set and the linearly superimposed seismic data from the second virtual source shot set. The full waveform inversion module is used to perform full waveform inversion on the seismic data after the concentrated amplitude normalization processing of the first virtual source shot and the seismic data after the concentrated amplitude normalization processing of the second virtual source shot, respectively, to obtain the velocity model and geological profile of the surrounding rock above the power tunnel, so as to predict the grade of the surrounding rock above the power tunnel based on the velocity model and the geological profile.
9. A storage medium, characterized in that: The storage medium stores computer-readable instructions, which, when executed by one or more processors, cause the one or more processors to perform the steps of the shallow buried power tunnel construction undulating strata detection method as described in any one of claims 1 to 7.
10. A computer device, characterized in that, include: One or more processors, and memory; The memory stores computer-readable instructions, which, when executed by the one or more processors, perform the steps of the shallow buried power tunnel construction undulating strata detection method as described in any one of claims 1 to 7.