Application of three-dimensional electrical resistivity tomography in urban zones by arbitrary electrode distribution survey design

Target-oriented optimized survey design and quantitative comparison for 3D electrical resistivity tomography

10.5194/egusphere-egu2020-3233 ◽

2020 ◽

Author(s):

Lincheng Jiang ◽

Gang Tian ◽

Bangbing Wang ◽

Amr Abd El-Raouf

Keyword(s):

Electrical Resistivity ◽

Electrical Resistivity Tomography ◽

Survey Design ◽

Quantitative Comparison ◽

Data Set ◽

Resistivity Tomography ◽

Near Surface ◽

Target Set ◽

Survey Designs

In recent decades, geoelectrical methods have played a very important role in near-surface investigation. The most widely used of these methods is electrical resistivity tomography (ERT). Regardless of the forward and inversion algorithms used, the original data collected from a survey is the most important factor for quality of the resulted model. However, 3D electrical resistivity survey design continues to be based on data sets recorded using one or more of the standard electrode arrays. There is a recognized need for the 3D survey design to get better resolution using fewer data. Choosing suitable data from the comprehensive data set is a great approach. By reasonable selecting, better resolution can be obtained with fewer electrodes and measurements than conventional arrays. Previous research has demonstrated that the optimized survey design using the 'Compare R' method can give a nice performance.This paper adds target-oriented selection and modified the original 'Compare R' method. The survey design should be focused on specific target areas, which need a priori information about the subsurface properties. We select electrodes and configurations as the target set by the comprehensive set firstly which meets the requirements of the target area. The number of measurements and electrodes is much less than the comprehensive set and the model resolution matrix takes less time to calculate. At the next step for rank, we calculate the sensitivity matrix of the target set only once and then calculate the contribution degree of each measurement separately from it. The time of iterative calculation of the resolution matrix when measurements set changing is less than the original method.The traditional method of evaluating RMS is not appropriate for comparing the quality of collected data by different survey designs. SSIM (structural similarity index) gives more reliable measures of image similarity better than the RMS. The curves of SSIM values in three dimensions and the average SSIM are given as quantitative comparisons. Besides, the frequency of electrodes utilized given to guides on selecting the highest used electrodes. Finally, the curves of the average relative resolution S and the number of electrodes as the number of measurements increase are given, which proves the method works effectively.The results show the significance of using target-oriented optimized survey design, as it selects fewer electrodes and arrays than the original CR method. Also, it produces better resolution than conventional arrays and takes less calculation time. 3D SSIM, frequency of electrodes used, the relationship between average relative resolution, number of electrodes and number of measurements, these quantitative comparison methods can effectively evaluate the data collected in various survey designs.

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Assessment of the Efficiency of Consolidation Treatment through Injections of Expanding Resins by Geotechnical Tests and 3D Electrical Resistivity Tomography

The Scientific World JOURNAL ◽

10.1155/2015/237930 ◽

2015 ◽

Vol 2015 ◽

pp. 1-13 ◽

Cited By ~ 5

Author(s):

T. Apuani ◽

G. P. Giani ◽

M. d’Attoli ◽

F. Fischanger ◽

G. Morelli ◽

...

Keyword(s):

Electrical Resistivity ◽

Electrical Resistivity Tomography ◽

Three Dimensional ◽

Test Site ◽

Mechanical Stiffness ◽

Foundation Soil ◽

Resistivity Tomography ◽

Consolidation Treatment ◽

Injection Process ◽

Geotechnical Tests

The design and execution of consolidation treatment of settled foundations by means of injection of polyurethane expanding resins require a proper investigation of the state of the foundation soil, in order to better identify anomalies responsible for the instability. To monitor the injection process, a procedure has been developed, which involves, in combination with traditional geotechnical tests, the application of a noninvasive, geophysical technique based on the electrical resistivity, which is strongly sensitive to presence of water or voids. Three-dimensional electrical resistivity tomography is a useful tool to produce effective 3D images of the foundation soils before, during, and after the injections. The achieved information allows designing the consolidation scheme and monitoring its effects on the treated volumes in real time. To better understand the complex processes induced by the treatment and to learn how variations of resistivity accompany increase of stiffness, an experiment was carried out in a full-scale test site. Injections of polyurethane expanding resin were performed as in real worksite conditions. Results confirm that the experimented approach by means of 3D resistivity imaging allows a reliable procedure of consolidation, and geotechnical tests demonstrate the increase of mechanical stiffness.

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Bedrock detection beneath river terrace deposits using three-dimensional electrical resistivity tomography

Geomorphology ◽

10.1016/j.geomorph.2012.03.034 ◽

2012 ◽

Vol 177-178 ◽

pp. 17-25 ◽

Cited By ~ 36

Author(s):

J.E. Chambers ◽

P.B. Wilkinson ◽

D. Wardrop ◽

A. Hameed ◽

I. Hill ◽

...

Keyword(s):

Electrical Resistivity ◽

Electrical Resistivity Tomography ◽

Three Dimensional ◽

River Terrace ◽

Resistivity Tomography

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Application of Two Dimensional Electrical Resistivity Tomography (ERT) For Moisture Detection in Thessaloniki’s Rotunda Pillars and Three-Dimensional ERT Modeling Using Optimized Electrode Arrays

ArchéoSciences ◽

10.4000/archeosciences.9443 ◽

2021 ◽

pp. 179-181

Author(s):

Prodromos Louvaris ◽

Panagiotis Tsourlos ◽

Gregory Tsokas ◽

George Vargemezis ◽

Nectaria Diamanti ◽

...

Keyword(s):

Electrical Resistivity ◽

Electrical Resistivity Tomography ◽

Three Dimensional ◽

Two Dimensional ◽

Electrode Arrays ◽

Resistivity Tomography ◽

Moisture Detection

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Preliminary use of ground-penetrating radar and electrical resistivity tomography to study tree roots in pine forests and poplar plantations

Functional Plant Biology ◽

10.1071/fp08062 ◽

2008 ◽

Vol 35 (10) ◽

pp. 1047 ◽

Cited By ~ 68

Author(s):

Terenzio Zenone ◽

Gianfranco Morelli ◽

Maurizio Teobaldelli ◽

Federico Fischanger ◽

Marco Matteucci ◽

...

Keyword(s):

Electrical Resistivity ◽

Ground Penetrating Radar ◽

Electrical Resistivity Tomography ◽

Water Saturation ◽

Three Dimensional ◽

Tree Roots ◽

Resistivity Tomography ◽

Shape Distribution ◽

Geophysical Surveys ◽

Ground Penetrating

In this study, we assess the possibility of using ground penetrating radar (GPR) and electrical resistivity tomography (ERT) as indirect non-destructive techniques for root detection. Two experimental sites were investigated: a poplar plantation [mean height of plants 25.7 m, diameter at breast height (dbh) 33 cm] and a pinewood forest mainly composed of Pinus pinea L. and Pinus pinaster Ait. (mean height 17 m, dbh 29 cm). GPR measures were taken using antennas of 900 and 1500 MHz applied in square and circular grids. ERT was previously tested along 2-D lines, compared with GPR sections and direct observation of the roots, and then using a complete 3-D acquisition technique. Three-dimensional reconstructions using grids of electrodes centred and evenly spaced around the tree were used in all cases (poplar and pine), and repeated in different periods in the pine forest (April, June and September) to investigate the influence of water saturation on the results obtainable. The investigated roots systems were entirely excavated using AIR-SPADE Series 2000. In order to acquire morphological information on the root system, to be compared with the GPR and ERT, poplar and pine roots were scanned using a portable on ground scanning LIDAR. In test sections analysed around the poplar trees, GPR with a high frequency antenna proved to be able to detect roots with very small diameters and different angles, with the geometry of survey lines ruling the intensity of individual reflectors. The comparison between 3-D images of the extracted roots obtained with a laser scan data point cloud and the GPR profile proved the potential of high density 3-D GPR in mapping the entire system in unsaturated soil, with a preference for sandy and silty terrain, with problems arising when clay is predominant. Clutter produced by gravel and pebbles, mixed with the presence of roots, can also be sources of noise for the GPR signals. The work performed on the pine trees shows that the shape, distribution and volume of roots system, can be coupled to the 3-D electrical resistivity variation of the soil model map. Geophysical surveys can be a useful approach to root investigation in describing both the shape and behaviour of the roots in the subsoil.

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