A geotechnical investigation method based on variable frequency high-density electrical method and a processing system thereof

Abstract

The application discloses a kind of geotechnical investigation method and processing system based on variable frequency high-density electrical method, it is related to geotechnical investigation technical field, including the following steps: a series of electrodes are laid on the surface of the area to be investigated, to form high-density electrode array, electrode array layout interval is dynamically adjusted according to the geological characteristics of the area to be investigated and the required resolution, the coverage of current injection and potential measurement is optimized;Different frequency currents are applied to the underground rock strata by the electrode array.The application optimizes current injection and measurement by high-density electrode array and dynamically adjusting electrode spacing, significantly improves the accuracy of investigation, uses multi-frequency current to detect different depth rock strata, enhances electrical contrast, effectively identifies geological anomaly body, generates high-resolution resistivity image in combination with high-precision measuring equipment and advanced data processing algorithm, improves the accuracy of geological analysis, provides scientific basis for engineering design, reduces construction risk.

Description

Technical Field

[0001] This invention relates to the field of geotechnical investigation technology, specifically to a geotechnical investigation method and processing system based on variable frequency high-density electrical resistivity tomography. Background Technology

[0002] High-density resistivity resistivity dating (HDLP) is a method for geotechnical investigation that utilizes resistivity measurement technology to detect the structure and properties of underground soil and rock masses. It involves arranging a series of electrodes on the surface, applying current, and measuring the potential difference to obtain resistivity information of soil and rock masses at different depths. The resistivity of soil and rock masses is affected by various factors, including their composition, water content, porosity, and temperature. Therefore, HDLP can be used to infer the distribution and physical properties of underground soil and rock masses.

[0003] In practice, high-density electrical resistivity tomography (EDT) uses a densely arrayed electrode to apply current and measure the response, obtaining resistivity profiles. These images visually display changes in the electrical characteristics of soil and rock masses at different depths, helping geotechnical engineers identify geological anomalies such as groundwater, fissures, cavities, and gas-bearing layers, and assess the safety and stability of engineering projects. This method offers advantages such as non-destructive testing, wide coverage, and high detection accuracy, and has been widely applied in geological exploration, environmental monitoring, and engineering construction.

[0004] The existing technology has the following shortcomings:

[0005] In complex geological environments, accurately identifying and distinguishing the different electrical characteristics of underground rock and soil strata to improve the resolution and accuracy of geotechnical exploration is a crucial issue. In traditional high-density electrical resistivity tomography (EDT), the electrical differences between rock and soil strata are relatively small, and the results are influenced by various factors such as groundwater, mineral composition, and pore structure, leading to significant uncertainties in resistivity measurements. This uncertainty makes it difficult to accurately distinguish different rock and soil strata during data interpretation, thus affecting the reliability of the exploration results. Therefore, an improved method is needed to enhance the contrast of electrical characteristics and improve data resolution and accuracy, enabling more effective identification and differentiation of special rock and soil strata in complex geological environments.

[0006] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a geotechnical exploration method and processing system based on variable frequency high-density electrical resistivity tomography (EDT). By deploying a high-density electrode array and dynamically adjusting the electrode spacing, current injection and potential measurement are optimized, significantly improving exploration accuracy and resolution. A multi-frequency current injection strategy is employed, combining low-frequency and high-frequency currents to probe geotechnical layers at different depths, enhancing electrical contrast and effectively identifying geological anomaly areas. High-precision potential difference measurement equipment is combined with advanced data processing algorithms to generate high-resolution images of underground resistivity distribution. Comprehensive analysis through multi-source data fusion improves the accuracy of geological body analysis and the reliability of exploration reports, providing a scientific basis for engineering design and decision-making, reducing construction risks, and thus solving the problems mentioned in the background technology.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a geotechnical investigation method based on variable frequency high-density electrical resistivity tomography, comprising the following steps:

[0009] A series of electrodes are deployed on the surface of the area to be explored to form a high-density electrode array. The spacing of the electrode array is dynamically adjusted according to the geological characteristics of the area to be explored and the required resolution to optimize the coverage of current injection and potential measurement.

[0010] By applying currents of different frequencies to underground rock and soil strata through an electrode array, including low-frequency currents and high-frequency currents, the low-frequency currents are used to penetrate deep rock and soil strata, while the high-frequency currents are used to detect shallow fine structures, thereby enhancing the electrical contrast of rock and soil strata at different depths.

[0011] While injecting current, a high-precision potential difference measurement device is used to collect potential difference data between each electrode. The measurement device has a real-time calibration function to eliminate the influence of environmental noise and electrode contact resistance, ensuring the accuracy and reliability of the potential difference data.

[0012] The collected potential difference data is processed by multidimensional data fusion, and high-resolution underground resistivity distribution images are generated by feature enhancement and inversion algorithms to show the changes in electrical characteristics of different rock and soil strata and automatically identify potential geological anomaly areas.

[0013] Based on the generated resistivity distribution image, combined with geological background information, data interpretation and analysis are performed to determine the properties, thickness, and distribution of underground soil and rock strata, generating a detailed geotechnical investigation report to guide subsequent engineering design and decision-making.

[0014] Preferably, the electrode array is deployed using an adaptive deployment method, which adjusts the electrode density and distribution in real time based on preliminary exploration data. This allows for increased electrode density in areas with complex geological conditions or structures, thereby improving the resistivity measurement accuracy and resolution in those areas. This adaptive deployment method can be achieved through a mobile electrode platform or a remotely controlled electrode deployment system, ensuring that the electrode position and spacing can be quickly adjusted during the exploration process to address different complex geological bodies and specific exploration needs.

[0015] Preferably, the application of current at different frequencies includes a multi-frequency current sequence that increases sequentially, from ultra-low frequency to ultra-high frequency, in order to acquire data on rock and soil strata at different depths and with different electrical characteristics. The application time of each frequency of current can be automatically adjusted according to specific geological conditions to ensure sufficient exploration and analysis of different rock and soil strata, maximize electrical contrast, and improve the accuracy of the overall exploration.

[0016] Preferably, the high-precision potential difference measurement device further includes a multi-channel synchronous measurement unit, capable of simultaneously acquiring the potential difference between multiple electrodes in real time. The device employs a low-noise amplifier and a high-precision analog-to-digital converter, ensuring the accuracy of the potential difference measurement even under conditions of weak signal or high background noise. The device also features an automatic detection function, capable of issuing alarms and prompting recalibration or adjustment of the measurement when there is poor electrode contact or abnormal data.

[0017] Preferably, multidimensional data fusion processing includes spatiotemporal domain fusion and frequency domain fusion, combining resistivity data from different times, spaces, and frequencies to eliminate noise and measurement errors, thereby improving the integrity and accuracy of the data. Spatiotemporal domain fusion achieves collaborative processing of different data by considering the time series of current application and the spatial layout of electrode placement; frequency domain fusion, through spectral analysis, removes useless high-frequency noise and retains key low-frequency features, thereby further improving the resolution of the underground resistivity distribution image.

[0018] Preferably, the feature enhancement algorithm includes a deep learning neural network model, which is trained to identify the electrical characteristics of complex soil and rock strata and potential geological anomaly areas. This model is trained based on a large amount of actual exploration data and can automatically learn patterns and regularities of different electrical characteristics, improving the accuracy and reliability of geological anomaly identification. Simultaneously, the model can continuously learn and update based on new exploration data, maintaining efficient geological analysis capabilities.

[0019] Preferably, the inversion algorithm combines constrained inversion and multi-level inversion to improve computational efficiency while ensuring data inversion accuracy. Constrained inversion introduces known geological information as prior constraints to reduce the non-uniqueness of solutions and improve the reliability of inversion results; multi-level inversion, on the other hand, uses a progressive approach, inverting shallow layers first and then deep layers, gradually optimizing the resistivity distribution image to ensure the accuracy of depth information.

[0020] Preferably, the process of generating the resistivity distribution image further includes noise filtering and outlier removal steps. Through adaptive noise suppression algorithms and statistical analysis methods, random noise and outliers in the resistivity data are automatically identified and filtered out. This process effectively reduces the impact of external interference and measurement errors, ensuring the clarity and accuracy of the resistivity image, thereby improving the visualization of the electrical characteristics of underground rock and soil strata.

[0021] Preferably, the data interpretation and analysis steps also include a comprehensive analysis module based on multi-source geological information. This module jointly analyzes resistivity distribution images with geological drilling data, geophysical well logging data, and remote sensing image data to form a multi-dimensional geological model. Through mutual verification and supplementation of multi-source data, the overall understanding of the structure and properties of underground soil and rock layers is improved, enhancing the accuracy and reliability of the exploration report.

[0022] Preferably, the geotechnical investigation report further includes a 3D visualization model and virtual reality (VR) display function, which can dynamically display the resistivity distribution and geological structure changes of underground rock and soil strata on a computer or mobile device. Through this function, users can interactively view geological information at different depths and orientations in real time, conduct virtual drilling and profile analysis, and provide intuitive and visual reference for engineering design and construction decisions.

[0023] A geotechnical investigation and processing system based on variable frequency high-density electrical resistivity tomography includes an electrode layout module, a current injection module, a data acquisition module, a data processing module, and a data analysis and report generation module.

[0024] The electrode deployment module deploys a series of electrodes on the surface of the area to be explored to form a high-density electrode array. The spacing of the electrode array is dynamically adjusted according to the geological characteristics of the area to be explored and the required resolution, thereby optimizing the coverage of current injection and potential measurement.

[0025] The current injection module applies currents of different frequencies to underground rock and soil strata through an electrode array. The different frequencies of current include low-frequency current and high-frequency current. Low-frequency current is used to penetrate deep rock and soil strata, while high-frequency current is used to detect shallow fine structures, thereby enhancing the electrical contrast of rock and soil strata at different depths.

[0026] The data acquisition module uses a high-precision potential difference measurement device to collect potential difference data between each electrode while injecting current. The measurement device has a real-time calibration function to eliminate the influence of environmental noise and electrode contact resistance, ensuring the accuracy and reliability of the potential difference data.

[0027] The data processing module performs multi-dimensional data fusion processing on the collected potential difference data, and uses feature enhancement and inversion algorithms to generate high-resolution underground resistivity distribution images, showing the changes in electrical characteristics of different rock and soil strata, and automatically identifying potential geological anomaly areas.

[0028] The data analysis and report generation module interprets and analyzes the generated resistivity distribution image in conjunction with geological background information to determine the properties, thickness, and distribution of underground soil and rock strata, and generates a detailed geotechnical investigation report to guide subsequent engineering design and decision-making.

[0029] The technical effects and advantages provided by the present invention in the above technical solution are as follows:

[0030] This invention improves exploration accuracy and resolution by deploying a high-density electrode array and dynamically adjusting the electrode spacing, optimizing the configuration according to geological characteristics and exploration needs. In complex geological environments, traditional fixed electrode deployment methods struggle to capture sufficient geological details, resulting in insufficient data quality and difficulty in accurately distinguishing the electrical characteristics of different rock and soil strata. This invention, by increasing electrode density and optimizing the deployment method, particularly in areas with complex geological structures such as faults, areas rich in groundwater, and gas-bearing regions, enhances the sensitivity to resistivity changes, enabling more precise reflection of rock and soil strata with subtle electrical differences at different depths. This method improves the accuracy of exploration data, providing more reliable data support for subsequent geological analysis and engineering design.

[0031] This invention achieves multi-frequency detection of rock and soil strata by applying currents of different frequencies, significantly enhancing the electrical contrast of rock and soil layers at different depths. Low-frequency currents are used to probe deep rock and soil layers, while high-frequency currents are used to acquire shallow, fine structures; the combination of the two provides more comprehensive information on underground electrical properties. This multi-frequency current injection strategy can not only penetrate rock and soil strata at different depths but also effectively distinguish geological bodies with subtle differences in electrical characteristics, thereby improving the ability to identify geological anomalies. Whether it is deep fault zones, groundwater distribution, or shallow cavities, fissures, and gas-bearing strata, this invention can clearly detect and present them, providing high-resolution resistivity distribution images for geological exploration and helping geotechnical engineers better understand the underground geological environment.

[0032] This invention generates high-resolution images of underground resistivity distribution using high-precision potential difference measurement equipment and advanced data processing algorithms. Combined with multi-source geological information for comprehensive analysis, it significantly enhances the scientific rigor and reliability of exploration reports. By automating the analysis of resistivity images using a deep learning neural network model, and integrating existing geological background information such as drilling data, well logging data, and remote sensing imagery, a multi-dimensional geological model is formed, enabling a more accurate description of the properties, thickness, and distribution of underground rock and soil strata. This comprehensive analysis method helps identify potential geological risks, reduces uncertainties and risks during engineering implementation, and ensures maximum project safety and economic benefits. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0034] Figure 1 This is a flowchart of a geotechnical investigation method based on variable frequency high-density electrical resistivity tomography (EDT) according to the present invention.

[0035] Figure 2 This is a schematic diagram of a rock and soil exploration and processing system based on variable frequency high-density electrical resistivity tomography (EDT) according to the present invention. Detailed Implementation

[0036] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that the description of this disclosure will be more complete and fully convey the concept of the exemplary embodiments to those skilled in the art.

[0037] This invention provides, for example Figure 1 The method for geotechnical investigation based on variable frequency high-density electrical resistivity tomography (EDT) includes the following steps:

[0038] A series of electrodes are deployed on the surface of the area to be explored to form a high-density electrode array. The spacing of the electrode array is dynamically adjusted according to the geological characteristics of the area to be explored and the required resolution to optimize the coverage of current injection and potential measurement.

[0039] By applying currents of different frequencies to underground rock and soil strata through an electrode array, including low-frequency currents and high-frequency currents, the low-frequency currents are used to penetrate deep rock and soil strata, while the high-frequency currents are used to detect shallow fine structures, thereby enhancing the electrical contrast of rock and soil strata at different depths.

[0040] While injecting current, a high-precision potential difference measurement device is used to collect potential difference data between each electrode. The measurement device has a real-time calibration function to eliminate the influence of environmental noise and electrode contact resistance, ensuring the accuracy and reliability of the potential difference data.

[0041] The collected potential difference data is processed by multidimensional data fusion, and high-resolution underground resistivity distribution images are generated by feature enhancement and inversion algorithms to show the changes in electrical characteristics of different rock and soil strata and automatically identify potential geological anomaly areas.

[0042] Based on the generated resistivity distribution image, combined with geological background information, data interpretation and analysis are performed to determine the properties, thickness, and distribution of underground rock and soil strata, generating a detailed exploration report to guide subsequent engineering design and decision-making.

[0043] Specific Implementation Method 1: In this specific implementation method, a high-density electrode array containing 100 electrodes is first deployed based on the geological characteristics and requirements of the area to be explored. In actual operation, to ensure exploration accuracy and efficiency, the electrode spacing is no longer fixed but dynamically adjusted according to the results of the preliminary geological survey and on-site conditions. Specifically, the electrode spacing can vary between 0.5m and 2m. By dynamically adjusting the electrode spacing, the electrode density can be appropriately increased in areas with more dramatic geological changes, such as fault zones, fracture zones, or areas rich in groundwater and shallow gas, to improve the resolution and measurement accuracy of the area, depending on the complexity of the geological structure or specific exploration needs. This means reducing the electrode spacing to 0.5m. Simultaneously, in areas with relatively simple or less varied geological conditions, the electrode spacing can be increased to 2m to save equipment and time costs and optimize the allocation of exploration resources. This adaptive electrode deployment method can improve exploration accuracy in complex geological environments and increase work efficiency when exploration conditions permit.

[0044] To further optimize the coverage of current injection and potential measurement, a high-density and regionalized electrode deployment strategy was adopted. This strategy requires the deployment of higher-density electrode arrays in areas with complex geological conditions, such as underground faults, fracture zones, gas-bearing layers, and areas with significant geological interface changes, resulting in more uniform current injection and more accurate potential measurement. During implementation, the electrodes are made of corrosion-resistant metals such as copper or stainless steel, and undergo special treatment to ensure long-term stable conductivity and durability. Furthermore, the electrode burial depth is carefully designed, typically with the top of the electrode buried between 0.3m and 0.5m. This effectively avoids interference from surface vegetation and soil while ensuring good contact between the electrode and the underground rock and soil layers, reducing the impact of contact resistance on the measurement results. This deployment strategy ensures effective current injection and potential difference measurement under various geological conditions, providing accurate and reliable resistivity data.

[0045] After the high-density electrode array is deployed, current injection and potential difference measurement become the next crucial operations. Different frequencies of current, primarily low-frequency and high-frequency, are applied to the underground soil and rock layers through the electrode array to probe deeper and shallower soil and rock structures, respectively. Specifically, low-frequency currents are typically below 10Hz, suitable for penetrating deep soil and rock layers, with a detection depth exceeding 50m; while high-frequency currents are above 1kHz, mainly used to detect shallow, fine structures, with a detection depth of approximately 10m. This multi-frequency current injection method makes the differences in electrical characteristics of soil and rock layers at different depths more pronounced, thereby enhancing electrical contrast and improving the identification accuracy of different soil and rock layers. During the current injection process, to ensure the accuracy and reliability of the data, a high-precision potential difference measurement device is also used. This device has a real-time calibration function, which can automatically eliminate the influence of environmental noise and electrode contact resistance, ensuring the accuracy of the measurement data. Through these measures, the obtained potential difference data has high resolution and high accuracy, laying a solid foundation for subsequent data processing and analysis. This method can not only effectively distinguish soil and rock layers with slight differences in electrical properties, but also accurately identify potential geological anomaly areas, providing a scientific and reliable basis for soil and rock exploration.

[0046] By employing an adaptive strategy of deploying high-density electrode arrays and dynamically adjusting electrode spacing, the accuracy of exploration in complex geological environments is effectively improved. This deployment method optimizes resources by reducing electrode spacing (to 0.5m) in areas with complex geological conditions to increase resolution, and increasing spacing (to 2m) in areas with simple geological conditions. Combined with corrosion-resistant materials and appropriate electrode burial depth, this ensures that the electrodes maintain stable conductivity over the long term and reduces the impact of contact resistance on measurements. Simultaneously, multi-frequency injection of low-frequency and high-frequency currents enhances the electrical contrast of rock and soil strata at different depths, enabling accurate detection and identification of both shallow and deep structures. This provides high-resolution potential difference data, improves the overall reliability and accuracy of the exploration, and ultimately provides a scientifically reliable basis for engineering design.

[0047] In geotechnical investigation, optimizing electrode placement is not limited to dynamically adjusting electrode spacing; it can also be achieved through various methods to further improve investigation accuracy and effectiveness. The core purpose of optimizing placement is to flexibly configure the electrode array according to the complexity of the geological environment and investigation needs, ensuring uniform current injection, accurate potential measurement, and the ability to capture subtle electrical differences in underground soil and rock layers.

[0048] First, diversifying electrode arrangement patterns is a crucial strategy for optimizing electrode deployment. For example, traditional electrode arrays typically employ linear, grid-like, or evenly spaced arrangements. However, in complex geological environments, eccentric or non-uniform arrangements can be chosen based on the specific circumstances. In areas with significant geological variations (such as fault zones and fracture zones), concentrating electrodes in these key areas enhances the electrical contrast of the region. This deployment method effectively improves resolution in areas with large local electrical differences, ensuring the acquisition of vital geological information. In other areas with less geological variation, appropriately increasing electrode spacing reduces redundant measurements and optimizes exploration efficiency.

[0049] Secondly, employing a layered electrode deployment method is also an optimization strategy. In some exploration areas, the depth and electrical characteristics of underground soil and rock layers vary significantly. Using a combination of shallow and deep electrode deployment—that is, denser electrode deployment in shallow areas and increased electrode spacing in deeper areas—can effectively enable detailed detection of geological information at different levels. This method helps to reduce unnecessary measurements and costs while ensuring exploration accuracy.

[0050] Furthermore, adjusting the orientation of the electrode array is also a crucial strategy for optimizing its placement. In complex geological environments, the electrical characteristics of underground soil and rock layers may exhibit significant directional differences. For example, in areas with distinct transverse faults, bedding, or water flow directions, appropriately adjusting the orientation of the electrodes to match the current injection with the geological structure can significantly improve the accuracy of capturing the electrical characteristics of geological bodies. By adjusting the orientation of the electrode array, the electrical responses of geological bodies can be simulated more effectively, achieving higher resolution and accuracy.

[0051] Furthermore, automated deployment and real-time adjustment are also cutting-edge optimization methods. In practice, real-time data from the geological exploration site can be combined with intelligent algorithms to automatically optimize electrode deployment. For example, the system can adjust electrode density and deployment patterns in real time based on data changes obtained during the exploration process to cope with different geological changes and exploration needs. This method not only improves the flexibility of exploration but also significantly enhances exploration efficiency and accuracy.

[0052] In summary, optimizing electrode layout not only enhances accuracy by dynamically adjusting electrode spacing, but also employs strategies such as diversified arrangement patterns, layered layout, orientation adjustment, and automated real-time optimization. This allows for more refined and efficient geotechnical investigations tailored to different geological environments and exploration needs, significantly improving the quality and reliability of exploration data.

[0053] Specific Implementation Method 2: Applying currents of different frequencies to underground soil and rock strata via an electrode array is a key step in improving the accuracy of identifying the electrical characteristics of underground soil and rock strata. To effectively detect soil and rock structures at different depths, the frequency range of the injected current is designed from ultra-low frequency to ultra-high frequency, specifically including a 10Hz low-frequency current and a 1kHz high-frequency current. The low-frequency current has strong penetrating power, capable of penetrating deep soil and rock layers and obtaining structural information of soil and rock strata at depths exceeding 50m. The high-frequency current is mainly used to detect shallow, fine structures, typically with an effective detection depth of around 10m. By injecting multiple frequencies of current, the electrical characteristics of soil and rock strata at different depths can be effectively distinguished, enhancing the electrical contrast between soil and rock strata at different depths. This method is particularly suitable for exploration under complex geological conditions, such as multi-layered soil and rock structures or areas rich in groundwater, helping to accurately identify and distinguish subtle changes and geological anomalies within soil and rock strata.

[0054] To ensure the effectiveness and accuracy of current injection, a multi-frequency current sequence injection technique with progressively increasing frequencies was introduced in the implementation. During current application, the frequency was gradually increased from low to high, maximizing the electrical characteristic information provided by each frequency while simultaneously probing the soil and rock layers. The application time for each frequency was automatically controlled by a computer and adjusted in real time according to geological conditions. In areas with significant electrical differences, the low-frequency current was applied for a longer time to obtain more detailed deep-layer information; while in areas with smaller electrical variations, the high-frequency current was applied for a longer time to obtain fine-grained shallow-layer structures. This method of dynamically adjusting the current application time better adapts to different geological conditions, improves electrical contrast, and thus effectively enhances the ability to identify geological anomalies.

[0055] Furthermore, during the current injection process, the high-precision potential difference measurement equipment is a crucial technical support, directly impacting the quality and accuracy of the data. This equipment employs a multi-channel synchronous measurement device, enabling real-time acquisition of potential differences between multiple electrodes simultaneously, effectively reducing measurement errors caused by time delays. The equipment integrates a low-noise amplifier and a high-precision analog-to-digital converter, allowing it to maintain high-precision data acquisition capabilities even in complex geological environments with weak signals or high background noise. To further ensure data accuracy, the equipment also features real-time calibration, automatically detecting changes in electrode contact resistance and eliminating the influence of environmental noise through correction algorithms. This high-precision, automatically calibrated potential difference measurement technology significantly improves the reliability of measurement data, providing a solid foundation for subsequent data processing and analysis. Ultimately, by combining multi-frequency current injection with high-precision measurement, a high-resolution image of underground resistivity distribution is generated, accurately displaying the electrical characteristics of different soil and rock strata and automatically identifying potential geological anomalies. This provides a scientific basis for geotechnical investigation reports, guiding subsequent engineering design and decision-making.

[0056] By employing a sequentially increasing multi-frequency current injection technique, detailed detection of soil and rock strata at different depths is achieved, effectively enhancing electrical contrast and making it particularly suitable for exploration in complex geological conditions. Low-frequency currents are used to probe deep structures, providing detailed information at penetration depths exceeding 50m, while high-frequency currents focus on detecting shallow, fine structures, making electrical characteristics clearer. Combined with a real-time controlled high-precision potential difference measurement device, this method, supported by multi-channel synchronous acquisition and low-noise amplification technology, maintains high data accuracy even in the presence of environmental noise. This efficient, multi-layered data acquisition and processing strategy ensures that the generated resistivity images accurately display changes in different underground soil and rock layers, improving the ability to identify geological anomalies and providing a reliable scientific basis for engineering design.

[0057] Specific Implementation Method 3: High-precision potential difference measurement equipment plays a crucial role in the current injection process. These devices are equipped with multi-channel synchronous measurement units, capable of simultaneously acquiring potential difference data between multiple electrodes. This design not only improves measurement efficiency but also significantly reduces data errors caused by time delays. The measurement equipment converts the potential difference signal into a digital signal for storage and analysis through a low-noise amplifier and a high-precision analog-to-digital converter. The multi-channel design of the equipment can process data from up to 32 channels in real time, ensuring measurement accuracy under complex geological conditions. Furthermore, the built-in real-time calibration function automatically detects and compensates for changes in electrode contact resistance, eliminating the influence of environmental noise and interference on the measurement results, thereby ensuring the accuracy and stability of the potential difference data. This high-precision measurement capability provides high-quality basic data for subsequent data analysis and geotechnical structure interpretation.

[0058] To further improve the accuracy and reliability of the data, this implementation introduces multi-dimensional data fusion processing technology. After processing, the collected potential difference data is used to generate a high-resolution image of underground resistivity distribution through feature enhancement and inversion algorithms. The feature enhancement algorithm eliminates random noise and measurement errors by weighting the measurement data from different electrodes, thereby highlighting geological features. In the inversion algorithm, a combination of constrained inversion and multi-level inversion is used. By introducing prior geological information constraints, the non-uniqueness of the solution is reduced, and the underground resistivity distribution is inverted layer by layer. First, shallow data is inverted to obtain a shallow resistivity distribution map. Then, depth information is gradually added to finally generate a complete high-resolution resistivity distribution image. This layer-by-layer inversion method not only improves the efficiency of data processing but also ensures the accuracy and reliability of depth information, better reflecting the true electrical characteristics of underground soil and rock layers.

[0059] After generating resistivity distribution images through data processing, the system combines these images with geological background information to conduct data interpretation and analysis. In this process, the data interpretation module uses a deep learning neural network model to analyze and interpret the generated resistivity images. This neural network model, trained on a large amount of actual exploration data, can automatically learn patterns and laws of different electrical characteristics and identify and classify features in the resistivity images based on geological background information. By jointly analyzing multi-source geological information (such as drilling data, well logging data, and remote sensing images) with resistivity distribution images, a multi-dimensional geological model is formed. This multi-source data fusion method can effectively verify and complement each other, providing a holistic understanding of the structure and properties of underground soil and rock layers. During the interpretation process, the system can automatically identify potential geological anomaly areas, such as groundwater zones, cavities, faults, and gas-bearing layers, laying the foundation for generating detailed geotechnical investigation reports. These reports describe in detail the properties, thickness, and distribution of underground soil and rock layers, providing a scientific basis for subsequent engineering design and decision-making, thereby effectively guiding the construction process and avoiding potential engineering risks.

[0060] By combining high-precision potential difference measurement equipment with multi-dimensional data fusion processing technology, the accuracy and reliability of geotechnical investigation are significantly improved. The equipment's multi-channel synchronous acquisition function, along with its built-in low-noise amplifier and high-precision analog-to-digital converter, ensures stable and high-precision data acquisition under complex geological conditions. Real-time calibration further eliminates the influence of environmental noise and contact resistance, guaranteeing the stability of the measurement data. Combined with feature enhancement and constrained inversion algorithms, the high-resolution resistivity images generated through layer-by-layer processing provide detailed and progressively in-depth information on underground soil and rock layers, enhancing the clarity and analytical capabilities of geological features. Through joint analysis with multi-source geological information, the system can automatically identify geological anomaly areas, providing a reliable basis for geotechnical investigation reports and assisting in engineering design and risk management.

[0061] This invention significantly improves exploration accuracy and resolution by deploying a high-density electrode array and dynamically adjusting the electrode spacing, optimizing the configuration according to geological characteristics and exploration needs. In complex geological environments, traditional fixed electrode deployment methods struggle to capture sufficient geological details, resulting in insufficient data quality and difficulty in accurately distinguishing the electrical characteristics of different soil and rock layers. This invention, by increasing electrode density and optimizing the deployment method, particularly in areas with complex geological structures such as fault zones and areas rich in groundwater, enhances the sensitivity to resistivity changes, enabling more precise reflection of soil and rock layers at different depths with subtle electrical differences.

[0062] This invention achieves multi-frequency detection of rock and soil strata by applying currents of different frequencies, significantly enhancing the electrical contrast of rock and soil strata at different depths. Low-frequency currents are used to probe deep rock and soil layers, while high-frequency currents are used to acquire shallow, fine structures; the combination of the two provides more comprehensive information on underground electrical properties. This multi-frequency current injection strategy can not only penetrate rock and soil layers at different depths but also effectively distinguish geological bodies with subtle differences in electrical characteristics, thereby improving the ability to identify geological anomalies. Whether it is deep fault zones, groundwater distribution, or shallow cavities, fissures, and gas-bearing areas, this invention can clearly detect and present them, providing high-resolution resistivity distribution images for geological exploration and helping geotechnical engineers better understand the underground geological environment.

[0063] This invention generates high-resolution images of underground resistivity distribution using high-precision potential difference measurement equipment and advanced data processing algorithms. Combined with multi-source geological information for comprehensive analysis, it significantly enhances the scientific rigor and reliability of exploration reports. By employing a deep learning neural network model to automatically analyze the resistivity images and integrating existing geological background information such as drilling data, well logging data, and remote sensing imagery, a multi-dimensional geological model is formed, more accurately describing the properties, thickness, and distribution of underground soil and rock layers. This comprehensive analysis method provides a scientific basis for engineering design and decision-making, helps identify potential geological risks, and formulates more rational engineering plans, thereby reducing uncertainties and risks during construction and ensuring the maximization of project safety and economic benefits.

[0064] This invention provides, for example Figure 2 The system shown is a geotechnical investigation and processing system based on variable frequency high-density electrical resistivity tomography, including an electrode layout module, a current injection module, a data acquisition module, a data processing module, and a data analysis and report generation module.

[0065] The electrode deployment module deploys a series of electrodes on the surface of the area to be explored to form a high-density electrode array. The spacing of the electrode array is dynamically adjusted according to the geological characteristics of the area to be explored and the required resolution, thereby optimizing the coverage of current injection and potential measurement.

[0066] The current injection module applies currents of different frequencies to underground rock and soil strata through an electrode array. The different frequencies of current include low-frequency current and high-frequency current. Low-frequency current is used to penetrate deep rock and soil strata, while high-frequency current is used to detect shallow fine structures, thereby enhancing the electrical contrast of rock and soil strata at different depths.

[0067] The data acquisition module uses a high-precision potential difference measurement device to collect potential difference data between each electrode while injecting current. The measurement device has a real-time calibration function to eliminate the influence of environmental noise and electrode contact resistance, ensuring the accuracy and reliability of the potential difference data.

[0068] The data processing module performs multi-dimensional data fusion processing on the collected potential difference data, and uses feature enhancement and inversion algorithms to generate high-resolution underground resistivity distribution images, showing the changes in electrical characteristics of different rock and soil strata, and automatically identifying potential geological anomaly areas.

[0069] The data analysis and report generation module interprets and analyzes the generated resistivity distribution image in conjunction with geological background information to determine the properties, thickness, and distribution of underground soil and rock strata, and generates a detailed geotechnical investigation report to guide subsequent engineering design and decision-making.

[0070] The present invention provides a geotechnical investigation method based on variable frequency high-density electrical resistivity tomography (VLT), which is implemented by the aforementioned geotechnical investigation and processing system based on VLT. For details of the specific method and process of the geotechnical investigation and processing system based on VLT, please refer to the aforementioned embodiment of the geotechnical investigation method based on VLT, which will not be repeated here.

[0071] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A geotechnical investigation method based on variable frequency high-density electrical resistivity tomography, characterized in that, Includes the following steps: A series of electrodes are deployed on the surface of the area to be explored to form a high-density electrode array. The spacing of the electrode array is dynamically adjusted according to the geological characteristics of the area to be explored and the required resolution to optimize the coverage of current injection and potential measurement. By applying currents of different frequencies to underground rock and soil strata through an electrode array, including low-frequency currents and high-frequency currents, the low-frequency currents are used to penetrate deep rock and soil strata, while the high-frequency currents are used to detect shallow fine structures, thereby enhancing the electrical contrast of rock and soil strata at different depths. While injecting current, a high-precision potential difference measurement device is used to collect potential difference data between each electrode. The measurement device has a real-time calibration function to eliminate the influence of environmental noise and electrode contact resistance, ensuring the accuracy and reliability of the potential difference data. The collected potential difference data is processed by multidimensional data fusion, and high-resolution underground resistivity distribution images are generated by feature enhancement and inversion algorithms to show the changes in electrical characteristics of different rock and soil strata and automatically identify potential geological anomaly areas. Based on the generated resistivity distribution image, combined with geological background information, data interpretation and analysis are performed to determine the properties, thickness, and distribution of underground soil and rock strata, generating a detailed geotechnical investigation report to guide subsequent engineering design and decision-making. The electrode array is deployed using an adaptive deployment method, which adjusts the density and distribution of electrodes in real time based on preliminary survey data. In areas with complex geological conditions or geological structures, the electrode density is increased to improve the resistivity measurement accuracy and resolution in those areas. The application of current at different frequencies includes a multi-frequency current sequence that increases sequentially, from ultra-low frequency to ultra-high frequency, in order to obtain data on soil and rock layers with different depths and electrical characteristics. The application time of current at each frequency is automatically adjusted according to specific geological conditions to ensure that different soil and rock layers are fully explored and analyzed, maximize electrical contrast, and improve the overall accuracy of the exploration. The feature enhancement algorithm includes a deep learning neural network model. The model is trained to identify complex electrical characteristics of rock and soil strata and potential geological anomaly areas. The training model is based on a large amount of actual exploration data and can automatically learn the patterns and rules of different electrical characteristics, thereby improving the accuracy and reliability of geological anomaly identification. At the same time, the training model can also continuously learn and update based on new exploration data to maintain efficient geological analysis capabilities. The inversion algorithm combines constrained inversion and multi-level inversion to improve computational efficiency while ensuring data inversion accuracy. Constrained inversion introduces known geological information as prior constraints to reduce the non-uniqueness of solutions and improve the reliability of inversion results. Multi-level inversion, on the other hand, proceeds step by step, first inverting shallow layers and then deep layers, gradually optimizing the resistivity distribution image to ensure the accuracy of depth information.

2. A geotechnical investigation method based on variable frequency high-density electrical resistivity tomography according to claim 1, characterized in that, The high-precision potential difference measurement device further includes a multi-channel synchronous measurement device, which can simultaneously acquire the potential difference between multiple electrodes in real time. Secondly, the high-precision potential difference measurement device uses a low-noise amplifier and a high-precision analog-to-digital converter to ensure the accuracy of the potential difference measurement. Finally, the high-precision potential difference measurement device also has an automatic detection function, which can issue an alarm when there is poor electrode contact or abnormal data, prompting recalibration or adjustment of the measurement.

3. A geotechnical investigation method based on variable frequency high-density electrical resistivity tomography according to claim 1, characterized in that, Multidimensional data fusion processing includes spatiotemporal domain fusion and frequency domain fusion. By combining resistivity data from different times, spaces and frequencies, noise and measurement errors are eliminated, and the integrity and accuracy of the data are improved. Spatiotemporal domain fusion achieves collaborative processing of different data by considering the time series of current application and the spatial layout of electrode placement. Frequency domain fusion, through spectral analysis, removes useless high-frequency noise and retains key low-frequency features, further improving the resolution of underground resistivity distribution images.

4. A geotechnical investigation method based on variable frequency high-density electrical resistivity tomography according to claim 1, characterized in that, The process of generating resistivity distribution images further includes noise filtering and outlier removal steps. Through adaptive noise suppression algorithms and statistical analysis methods, random noise and outliers in resistivity data are automatically identified and filtered out, improving the visualization effect of electrical characteristics of underground rock and soil strata.

5. A geotechnical investigation method based on variable frequency high-density electrical resistivity tomography (EDT) according to claim 1, characterized in that, The data interpretation and analysis steps also include a comprehensive analysis module based on multi-source geological information. This module combines resistivity distribution images with geological drilling data, geophysical well logging data, and remote sensing image data to form a multi-dimensional geological model. Through mutual verification and supplementation of multi-source data, it improves the overall understanding of the structure and properties of underground rock and soil strata, and enhances the accuracy and reliability of the exploration report. The geotechnical investigation report further includes a 3D visualization model and virtual reality display function, which can dynamically display the resistivity distribution and geological structure changes of underground rock and soil strata on computers or mobile devices, and interactively view geological information at different depths and orientations in real time, conduct virtual drilling and profile analysis, and provide intuitive and visual reference for engineering design and construction decisions.

6. A geotechnical investigation and processing system based on variable frequency high-density electrical resistivity tomography (EPT), used to implement the geotechnical investigation method based on variable frequency high-density EPT as described in any one of claims 1-5, characterized in that, include: Electrode placement module, current injection module, data acquisition module, data processing module, and data analysis and report generation module; The electrode deployment module deploys a series of electrodes on the surface of the area to be explored to form a high-density electrode array. The spacing of the electrode array is dynamically adjusted according to the geological characteristics of the area to be explored and the required resolution, thereby optimizing the coverage of current injection and potential measurement. The current injection module applies currents of different frequencies to underground rock and soil strata through an electrode array. The different frequencies of current include low-frequency current and high-frequency current. Low-frequency current is used to penetrate deep rock and soil strata, while high-frequency current is used to detect shallow fine structures, thereby enhancing the electrical contrast of rock and soil strata at different depths. The data acquisition module uses a high-precision potential difference measurement device to collect potential difference data between each electrode while injecting current. The measurement device has a real-time calibration function to eliminate the influence of environmental noise and electrode contact resistance, ensuring the accuracy and reliability of the potential difference data. The data processing module performs multi-dimensional data fusion processing on the collected potential difference data, and uses feature enhancement and inversion algorithms to generate high-resolution underground resistivity distribution images, showing the changes in electrical characteristics of different rock and soil strata, and automatically identifying potential geological anomaly areas. The data analysis and report generation module interprets and analyzes the generated resistivity distribution image in conjunction with geological background information to determine the properties, thickness, and distribution of underground soil and rock strata, and generates a detailed geotechnical investigation report to guide subsequent engineering design and decision-making.

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