Multiconfiguration GPR measurements for geometric fracture characterization in limestone cliffs (Alps) - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Geophysics Year : 2006

Multiconfiguration GPR measurements for geometric fracture characterization in limestone cliffs (Alps)

Abstract

Until now, geophysical methods have been rarely used to investigate vertical limestone cliffs, mainly due to the extreme conditions for data acquisition. Nevertheless, these techniques are the only available methods which could provide information on the internal state or a rock mass in terms of discontinuities, which play a major role in rock-fall hazards. In this case study, detailed GPR measurements were carried out on a test site with different acquisition configurations deployed on vertical cliff faces. Conventional 2D profiles, common midpoints (CMP) and transmission data were acquired to evaluate the potential of radar waves to improve the characterization of the geometry and properties of the main discontinuities (fractures) within the massif. The results show that the 3D geometry of fractures, which is a crucial parameter for stability assessment, can be retrieved by combining vertical and horizontal profiles performed along the cliff. CMP profiles acquired along the cliff allow a velocity profile to be obtained as a function of depth. Finally, transmission experiments, which generate complex radargrams, have provided valuable and quantitative information on the rock mass, through the modelling of the waves generated. On the other hand, a velocity tomography obtained from the first arrivals travelling through the rock mass from the transmitters to the receivers, shows an image of the investigated zone with a poor resolution.
Fichier principal
Vignette du fichier
GPR-Garambois-revised-clear2.pdf (2.6 Mo) Télécharger le fichier
Origin : Files produced by the author(s)
Loading...

Dates and versions

insu-00196696 , version 1 (13-12-2007)

Identifiers

Cite

Mathieu Jeannin, Stéphane Garambois, Colette Grégoire, Denis Jongmans. Multiconfiguration GPR measurements for geometric fracture characterization in limestone cliffs (Alps). Geophysics, 2006, 71 (3), pp.B85-B92. ⟨10.1190/1.2194526⟩. ⟨insu-00196696⟩

Collections

INSU UGA
206 View
790 Download

Altmetric

Share

Gmail Facebook X LinkedIn More