This document specifies the measurement of stress changes by means of total pressure cells (TPC). It refers to cells which are permanently installed either in the ground, in adjacent engineered structures or in contact planes between any two media. 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 18674-1:2015. If applied in conjunction with ISO 18674-4:2019, this document allows the determination of effective stress acting in the ground. Indirect stress monitoring methods (see 18674-1:2015, Table B.2) are not subject of this document. This document is applicable to: monitoring changes of the state of stress in the ground and in geo-engineered structures (e.g. in earth fill dams or tunnel lining); monitoring contact pressures at the interface between two media (e.g. earth pressure on retaining wall; contact pressure at the base of a foundation); checking geotechnical designs and adjustment of construction in connection with the Observational Design procedure; evaluating stability during or after construction. 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 total pressure cells as part of the geotechnical investigation and testing according to EN 1997-1 and EN 1997-2, see References [1] and[2].