Patent ID: 7532780

Claim:
Process for locating and measuring deformations in soil or infill associated with a civil engineering structure, comprising providing at least one geosynthetic fabric ( 1 ) having yarns and containing a plurality of optical fibres ( 2 a to 2 e ) in parallel and capable of transmitting signals, and applying the geosynthetic fabric in the said structure or on soil under the said structure, the said optical fibres containing Bragg gratings ( 3 ), evenly spaced in series ( 4 ) of N 1 consecutive gratings that correspond to the same wavelength, the said series being themselves distributed in identical sets, each of which contains N 2 consecutive series that correspond to different wavelengths, and by the fact that, in at least two optical fibres, the numbers N 1 of gratings of a series and the numbers N 2 of series ( 4 ) of a set ( 5 ) are determined in such as way that the measurement of differences between the wavelengths of the incident light transmitted in each of the said optical fibres and the wavelengths of the light reflected by the Bragg gratings enable to locate the deformations to which the structure is subjected on the one hand and, on the other, to measure the elongation of the said optical fibres where the deformation occurs.