Fibre Optic Cone Penetrometer

This paper presents a novel prototype cone penetrometer for piezocone penetration tests (CPTU). It is equipped with Fibre Optic (FO) sensors for measuring cone resistance (q(c)) and sleeve friction (f(s)). The FO sensors replace the classical, electric strain-gauges. Field results, laboratory calibration and uncertainty assessment show capability of achieving qc and fs values that are well within Application Class 1 of ISO 22476-1 "electrical cone and piezocone penetration test". This makes the FO cone penetrometer particularly suitable for use in very soft clays, silts and peat, i.e. Soil A and Interpretation H of ISO 22476-1. The cone penetrometer has potential to meet a significantly more stringent, Dutch Application Class 1+.