GPR full-waveform inversion of a variably saturated soil-aquifer system

Klotzsche, Anja; Vereecken, Harry; Kruk, Jan van der

doi:10.1016/j.jappgeo.2019.103823

Cited by 15 publications

(4 citation statements)

References 45 publications

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“…Ground penetrating radar is highly effective and accurate for interpreting the results, but its detection depth is limited under the technical limitations of the method itself, for example, the transmitting power is relatively small compared to the MT method. As a result, one cannot address the goaf with the depth of >100 m by using GPR (Cheng et al, 2010;Klotzsche et al, 2019;Ozkaya et al, 2021). Compared with other methods, transient electromagnetic method (TEM) is notably advantageous for detecting water-bearing coal goaf.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of water-bearing coal goaf using ground-borehole TEM—a case study of Tongxin Coal Mine, Shanxi Provice, China

Yang,

Peng,

Shan

et al. 2024

Front. Earth Sci.

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Transient electromagnetic method (TEM) is widely used in coalfield hydrogeological exploration and goaf investigation. However, given the limitations of the method, the vertical resolution of ground TEM is somewhat low for effectively detecting water-bearing coal goaf. Compared with ground TEM, ground-borehole TEM is characterized by a relatively better ability for detecting low-resistivity target bodies. In this study, a low-resistivity thin plate model was established, and the ground-borehole TEM electromagnetic responses of different points (within and without of the plate) were numerically simulated. We considered an exploration project in Datong City (Shanxi Province, China) as a study case, to conduct the field investigation, examine the characteristics of ground-borehole TEM electromagnetic responses under different situations, and validate the numerical model as well, including (a) water-bearing coal goaf and (b) solid coal. The result showed that, (a) the longer the sampling time is, the weaker the electromagnetic response of ground-borehole TEM will be; (2) ground-borehole TEM stands out with a high vertical resolution for water-bearing coal goaf; (c) the extreme points of the Z component and the polarity changing points of the X and Y components can indicate the interface where the physical properties alternated.

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Section: Introductionmentioning

confidence: 99%

Numerical simulation of water-bearing coal goaf using ground-borehole TEM—a case study of Tongxin Coal Mine, Shanxi Provice, China

Yang,

Peng,

Shan

et al. 2024

Front. Earth Sci.

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“…In 2019, Klotzsche, Anja et al, using crosshole GPR full-waveform inversion to visualize a soil aquifer system with variable saturation in critical regions, estimated four effective source wavelets with different source wavelets during inversion depending on the transmitter and receiver present in the saturated and/or unsaturated regions. Experiments have shown that this method can be used for imaging over the entire depth range starting from critical regions and can be applied to a wide range of applications [30]. Full waveform inversion is often used to estimate the geophysical parameters of recorded waveforms (observations) and is often expressed as a least squares optimization problem, but least squares FWI has a cycle jump problem.…”

Section: Introductionmentioning

confidence: 99%

A Real-Time Permittivity Estimation Method for Stepped-Frequency Ground-Penetrating Radar by Full-Waveform Inversion

Li,

Ye,

Kong

et al. 2023

Remote Sensing

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Ground-penetrating radar (GPR) has been widely used in estimating the permittivity of mediums. The radar echo amplitude method is an important method used by GPR in this estimation, the basic step of which is to deduce the magnitude of the permittivity according to the relationship between the reflection coefficient and the permittivity. Based on the basic principle of the radar echo amplitude method, this paper proposes a full-wave inversion real-time permittivity estimation method that can be used for stepped-frequency GPR (SFGPR), which offers high efficiency, accuracy, and generalization ability. The characteristics of this method are mainly reflected in the following four aspects: Using the SFGPR system and introducing a layered media detection model, we can complete waveform compensation optimization with high precision. The distance between the antenna and the surface of the reflective medium is extracted from the time domain waveform without manual measurement, avoiding human measurement errors. The inversion of the total reflection waveform at the required height works under the principle of an electromagnetic field, eliminating the need for repeated metal plate calibration experiments and improving work efficiency and waveform accuracy. In a continuous measurement line, the total reflection waveform inversion on each measurement point can be efficiently completed, and the change of permittivity on the measurement line can be obtained. To evaluate the feasibility of the proposed method, we performed experiments on a wall of known thickness, and the permittivity estimation was basically consistent with that of the dielectric probe, physical model calculation, and wall penetration. We also successfully applied this method to the dielectric property analysis of adobe samples. The results indicate that the proposed method can help grasp the condition of a measured medium, which can ensure the accuracy of detection and improve subsequent data processing efficiency.

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“…It is at present not standard procedure to model antennae explicitly and it is therefore necessary to estimate a source wavelet, which is typically assumed constant for a given survey. Furthermore, the FWI results depend heavily on the choice of starting model (e.g., Klotzsche, Vereecken, & van der Kruk, 2019; Z. Zhou et al., 2021), as the method requires a starting model that fulfills that its forward response lies within half a period of the observed waveform data to enable global convergence of the algorithm (G. Meles et al., 2011). The estimated structures in the dielectrical permittivity tomograms are considered more reliable than the conductivity tomograms, as investigated in Oberröhrmann et al.…”

Section: Introductionmentioning

confidence: 99%

Accounting for Modeling Errors in Linear Inversion of Crosshole Ground‐Penetrating Radar Amplitude Data: Detecting Sand in Clayey Till

et al. 2022

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Mapping high permeability sand occurrences in clayey till is fundamental for protecting the underlying drinking water resources. Crosshole ground penetrating radar (GPR) amplitude data have the potential to differentiate between sand and clay, and can provide 2D subsurface models with a decimeter‐scale resolution. We develop a probabilistic straight‐ray‐based inversion scheme, where we account for the forward modeling error arising from choosing a straight‐ray forward solver. The forward modeling error is described by a Gaussian probability distribution and included in the total noise model by addition of covariance models. Due to the linear formulation, we are able to decouple the inversion of traveltime and amplitude data and obtain results fast. We evaluate the approach through a synthetic study, where synthetic traveltime and amplitude data are inverted to obtain slowness and attenuation tomograms using several noise model scenarios. We find that accounting for the forward modeling error is fundamental to successfully obtain tomograms without artifacts. This is especially the case for inversion of amplitude data since the structure of the noise model for the forward modeling error is significantly different from the other data error models. Overall, inversion of field data confirms the results from the synthetic study; however, amplitude inversion performs slightly better than traveltime inversion. We are able to characterize a 0.4–0.6 m thick sand layer as well as internal variations in the clayey till matching observed geological information from borehole logs and excavation.

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GPR full-waveform inversion of a variably saturated soil-aquifer system

Cited by 15 publications

References 45 publications

Numerical simulation of water-bearing coal goaf using ground-borehole TEM—a case study of Tongxin Coal Mine, Shanxi Provice, China

Numerical simulation of water-bearing coal goaf using ground-borehole TEM—a case study of Tongxin Coal Mine, Shanxi Provice, China

A Real-Time Permittivity Estimation Method for Stepped-Frequency Ground-Penetrating Radar by Full-Waveform Inversion

Accounting for Modeling Errors in Linear Inversion of Crosshole Ground‐Penetrating Radar Amplitude Data: Detecting Sand in Clayey Till

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