Abstract

Geotechnical in-situ test methods provide valuable data for asset development, operation, and decommissioning. For confidence in test results, industry typically requires calibration and verification of in-situ test sensors to be conducted in a calibration laboratory. A calibration laboratory typically operates according to ISO/IEC 17025 (2017) ‘general requirements for the competence of testing and calibration laboratories’, or similar standard. This paper summarises observations from practice, with focus on the following challenges (1) evaluation of measurement uncertainty of key parameter values for which no standardised methods or verification materials are available, (2) validation of test methods with no backup from a formal standard published by a standardisation organisation and (3) field test site and interlaboratory comparisons within a competitive industry setting. Specific examples are presented for the (1) estimation of calibration uncertainty for sleeve friction of a subtraction-type cone penetrometer and (2) method validation for thermal conductivity of soil derived from in-situ heat flow measurements.