scholarly journals Synthetic Study of Boulder Detection Using Multi-Configuration Combination of Cross-Hole ERT and Its Field Application in Xiamen Metro, China

2021 ◽  
Vol 11 (24) ◽  
pp. 11860
Author(s):  
Ningbo Li ◽  
Zhao Dong ◽  
Zhengyu Liu ◽  
Bing Yan ◽  
Kai Wang ◽  
...  
Keyword(s):  
Electrical Resistivity Tomography ◽  
Random Distribution ◽  
Numerical Models ◽  
Field Application ◽  
Rail Transportation ◽  
Resistivity Tomography ◽  
Urban Rail ◽  
Fast Development ◽  
Set Up

With the fast development of urban rail transportation, shield construction has been widely used in tunnel construction in China. It is very important to detect the random distribution of boulders, which may cause geological problems. Cross-hole electrical resistivity tomography (ERT) has the advantage of precise detection, but it has not been systematically studied in solitary rock detection. Therefore, we set up several numerical models and proposed weighted inversion, to improve the capacity for detecting boulders. Subsequently, the method was applied to the Xiamen Metro Line 1, where it was highly likely to encounter boulders. All the test boreholes revealed the presence of boulders, and their location and size were consistent with the geophysics results. This study demonstrated the suitability of weighted inversion based on a multi-configuration combination of cross-hole ERT for the detection of boulders. This case study provides new engineering perspectives on how to detect boulders.

scholarly journals Comparison between electrical resistivity tomography and tunnel seismic prediction 303 methods for detecting the water zone ahead of the tunnel face: A case study

2020 ◽  
Vol 12 (1) ◽  
pp. 1094-1104
Author(s):  
Nima Dastanboo ◽  
Xiao-Qing Li ◽  
Hamed Gharibdoost
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Geological Structure ◽  
Rock Properties ◽  
Electrical Tomography ◽  
Tunnel Face ◽  
Resistivity Tomography ◽  
Geological Conditions ◽  
Seismic Prediction

AbstractIn deep tunnels with hydro-geological conditions, it is paramount to investigate the geological structure of the region before excavating a tunnel; otherwise, unanticipated accidents may cause serious damage and delay the project. The purpose of this study is to investigate the geological properties ahead of a tunnel face using electrical resistivity tomography (ERT) and tunnel seismic prediction (TSP) methods. During construction of the Nosoud Tunnel located in western Iran, ERT and TSP 303 methods were employed to predict geological conditions ahead of the tunnel face. In this article, the results of applying these methods are discussed. In this case, we have compared the results of the ERT method with those of the TSP 303 method. This work utilizes seismic methods and electrical tomography as two geophysical techniques are able to detect rock properties ahead of a tunnel face. This study shows that although the results of these two methods are in good agreement with each other, the results of TSP 303 are more accurate and higher quality. Also, we believe that using another geophysical method, in addition to TSP 303, could be helpful in making decisions in support of excavation, especially in complicated geological conditions.

scholarly journals Enhancing Electrical Contact with a Commercial Polymer for Electrical Resistivity Tomography on Archaeological Sites: A Case Study

2020 ◽  
Author(s):  
Marco D. Vásconez-Maza ◽  
Pedro Martínez-Pagán ◽  
Hasan Aktarakçi ◽  
María C. García-Nieto ◽  
Marcos A. Martínez-Segura
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Electrical Contact ◽  
Archaeological Sites ◽  
Resistivity Tomography ◽  
Tomography Method ◽  
Electrical Data

This communication reports an improvement of the quality of the electrical data obtained from the application of electrical resistivity tomography method on archaeological studies. The electrical contact between ground and electrode enhances significantly by using carbomer-based gel during the electrical resistivity tomography measurements. Not only does the gel promote the conservation of the building surface under investigation, but it also virtually eliminates the necessity of conventional spike electrodes, which in many archaeological studies are inadequate or not permitted. Results evidenced an enhancement in the quality of the electrical data obtained in the order of thousands of units compared with those without using the carbomer-based gel. The potential and capabilities of this affordable gel make it appropriate to be applied to other geoelectrical studies beyond archaeological investigations. Moreover, it might solve corrosion issues on conventional spike electrodes, and electrical multicore cables usually provoked for added saltwater attempting to improve the electrical contact.

scholarly journals Study of Seasonal Rainfall Infiltration via Time-Lapse Surface Electrical Resistivity Tomography: Case Study of Gamboa Area, Panama Canal Watershed

2013 ◽  
Vol 6 ◽  
pp. ASWR.S12306 ◽  
Author(s):  
Alexis Mojica ◽  
Irving Díaz ◽  
Carlos A. Ho ◽  
Fred Ogden ◽  
Reinhardt Pinzón ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Water Content ◽  
Electrical Resistivity Tomography ◽  
Time Lapse ◽  
Panama Canal ◽  
Resistivity Tomography ◽  
Rainwater Infiltration ◽  
Strong Inversion ◽  
Percent Difference

The present investigation was focused on the variations in rainwater infiltration experienced by soils of Gamboa zone (Panama Canal Watershed) during various seasons of the year, employing a time-lapse analysis of electrical resistivity tomography (ERT). In 2009, a total of 3 geoelectrical tests were undertaken during the dry, transition and rainy seasons across a profile 47 m in length, strategically distributed on site. The results obtained in this study showed strong variations in calculated resistivity between these seasons, taking the dry season as a reference with decreases and increases of percent difference of resistivity between -20% and -100%, and between 50% and 100%, respectively. These decreases, when displayed through a sequence of time-lapse images, reveal a superficial extension of the water content variations along the entire profile, as well as strong inversion artifacts showing false increases of calculated electrical resistivity. Decreases are the product of the rainfall increase obtained in this type of tropical environment; permanent conductive anomalies in 3 tests are associated with the streams close to the study site. The results of this work were compared with a simulation resulting from a series of bidimensional models applied to the 3 studies evaluated: dry, transition and rainy seasons.

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