Fiber optic sensor for use in flat plate dilatometer for geotechnical investigation

The possibility of using fiber optic sensors in geo-technical measurements is investigated with the aim of improving measurement performances of parameters which are of geo-technical interest and which can be indirectly measured starting from geo-technical probe strain data. This work refers to the use of real geo-technical probes and particular attention has been paid to the flat dilatometer, in order to evaluate the effect on measurement performances (resolution, sensitivity, accuracy) of using fiber optic sensors with respect to traditional ones. Design methodology is described in order to detect solutions able to improve not only measurement accuracy, but also resolution and reliability. In particular the effect of sensor position, size and installation has been studied by means of a theoretical and experimental study. Preliminary tests are discussed, which allowed to experimentally verify the system behaviour and which have been carried out on a test rig specifically designed and set-up