| Civil Engineering |
 |
Geophysical methods are selected according to the problem at hand, in addition to the geological data available and prevailing environmental conditions. The method proposed uses the physical parameters which are expected to highlight the targeted phenomenon. Radar-Tomography Detailed shallow investigation with ground-penetrating radar was combined with a more extensive survey using tomography to analyze the heterogeneity of the strata in a 14 m thick section.
 The decompressed zones located at very shallow depths can be distinguished on the radar section in violet (on the left) while the "quality" of the deeper strata (compactness, water content, lithology) is expressed on the tomography section (on the right) in the form of first arrival (P) propagation velocities. The values increase from blue to red through green and yellow (1400 m/s to 2000 m/s).
Ground-penetrating radar was used inside a sewer tunnel to determine dissolution phenomena within gypseous marls in contact with or very close to the concrete wall of the structure (1 gigahertz antenna). Seismic Reflection Main structural features, angled fractures and lithological series stand out on this seismic reflection section made along the tunnel route for the future Lyons-Turin rail link.
 These results were obtained in extremely rugged mountainous areas (3000-metre altitude). |
|
||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||
|
|
|
|
|||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||
| ||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||
Ground-Penetrating Radar