ISO 18674-7:2025

Geotechnical investigation and testing — Geotechnical monitoring by field instrumentation — Part 7: Measurement of strains: Strain gauges ISO 18674-7:2025

Publication date:   Nov 27, 2025

Scope

This document specifies the measurement of strain by means of strain gauges and strainmeters carried out for geotechnical monitoring. General rules of performance monitoring of the ground, of structures interacting with the ground, of geotechnical fills and of geotechnical works are presented in ISO 18674-1.
This document is applicable to:

performance monitoring of
1-D structural members such as piles, struts, props and anchor tendons;
2-D structural members such as foundation plates, sheet piles, diaphragm walls, retaining walls and shotcrete/concrete tunnel linings;
3-D structural members such as gravity dams, earth- and rock-fill dams, embankments and reinforced soil structures;
checking geotechnical designs and adjustment of construction in connection with the observational design procedure;
evaluating stability during or after construction.

With the aid of a stress-strain relationship of the material, strain data can be converted into stress and/or forces (for 1-D members; see ISO 18674-8) or stresses (for 2-D and 3-D members, see ISO 18674-5).
NOTE            This document fulfils the requirements for the performance monitoring of the ground, of structures interacting with the ground and of geotechnical works by the means of strain measuring instruments as part of the geotechnical investigation and testing in accordance with References [1] and [2].