Time-lapse cross-hole electrical resistivity tomography monitoring effects of an urban tunnel
| Autor: | Enric Vázquez-Suñé, Juanjo Ledo, Fabian Bellmunt, Ester Falgàs, V. Velasco, Alex Marcuello, Pilar Queralt, B. Benjumea |
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| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament d'Enginyeria del Terreny, Cartogràfica i Geofísica, Universitat Politècnica de Catalunya. GHS - Grup d'Hidrologia Subterrània |
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Void (astronomy)
Engineering Túnels -- Projectes i construcció Test site business.industry Well logging Drilling Enginyeria civil::Geomàtica::Sistemes d'informació geogràfica [Àrees temàtiques de la UPC] Cross-hole apparent resistivity pseudosection Tunnel boring machine Cross hole Geophysics Experimental electrodes Electrical resistivity and conductivity Electrical resistivity tomography (ERT) Geotechnical engineering Electrical resistivity tomography Tunnels -- Design and construction -- Data processing business Electrical conductor |
| Zdroj: | UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) Recercat. Dipósit de la Recerca de Catalunya instname |
| Popis: | Tunnel construction in urban areas has recently become a topic of interest and has increased the use of tunnel boring machines. Monitoring subsurface effects due to tunnel building in urban areas with conventional surface geophysical techniques is not an easy task because of space constraints. Taking advantage of the construction of a new metro line in Barcelona (Spain), a geoelectrical experiment, which included borehole logging and time-lapse cross-hole measurements using permanent electrode deployments, was designed to characterise and to study the subsurface effects of the tunnel drilling in a test site. We present a case study in which the differences between time-lapse cross-hole resistivity measurements acquired before, during and after the tunnel drilling below the test site have been calculated using three different procedures: a constrained time-lapse inversion, a model subtraction and an inversion of the normalised data ratio. The three procedures have provided satisfactory images of the resistivity changes and tunnel geometry, but resistivity changes for the tunnel void were lower than predicted by modelling. This behaviour has been explained by considering a conductive zone around the tunnel. Further, an apparent resistivity pseudosection for the cross-hole data, equivalent to the case of the equatorial dipole–dipole on the surface, is introduced. |
| Databáze: | OpenAIRE |
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