A novel fibre-optic pore pressure sensor for soil element testing

Abstract

Interpretation of element testing in soil mechanics can be enhanced to a large extent with the use of local pressure measurements, helping in quantifying the consequences of non-uniform stress, strain, and pore pressure fields within the sample. Available diaphragm pressure transducers can be useful to this aim; however, they suffer from several limitations. A novel Fabry–Pérot fibre-optic sensor for local measurement of pore water pressure within the sample is presented and discussed. The sensor addresses several limitations of current mid-plane diaphragm transducers, including long-term drifting, temperature sensitivity, and maintenance difficulties. The new sensor offers significant advantages in terms of reduced sample disturbance, data acquisition frequency, and response time.