EN ISO 18674-2:2016 PDF

Overview

EN ISO 18674-2:2016 - "Geotechnical monitoring by field instrumentation - Part 2: Measurement of displacements along a line: Extensometers" - defines how to measure lineal displacements in soil, fill and rock using extensometers as part of geotechnical monitoring. It supplements the general rules in ISO 18674‑1 and, when used with ISO 18674‑3, enables determination of displacements in any direction. The standard is intended for performance monitoring of ground, structures interacting with the ground and geotechnical works.

Key topics and technical requirements

• Scope and applicability: monitoring behaviour of soils, fills and rock; stability assessment; verification of Observational Design; deriving geotechnical parameters (e.g., from pile load tests or trial tunnelling).
• Instrument types: in-place extensometers (rod, wire, chain, single- or multiple-point), probe extensometers and tape (convergence) extensometers.
• Components and installation: anchors, connecting elements, measuring heads, guide tubes and surface components; installation procedures for boreholes and fills.
• Measurement practice: instrument checks, calibration, measuring range and accuracy requirements, recommended measuring procedures and frequency.
• Data processing and evaluation: procedures for converting raw readings into displacements along the measuring line and assessing measurement validity.
• Reporting: mandatory content for installation reports and monitoring reports; annexes provide measuring/evaluation procedures, backfill guidance, example applications and measurement examples.

Practical applications

• Monitoring ground and structure interaction during construction (excavations, retaining walls, foundations).
• Slope stability assessment for natural slopes, embankments, slope cuts and landslides.
• Performance verification through the Observational Design procedure and construction control.
• Deriving geotechnical key parameters from field tests such as pile load tests or trial tunnelling.
• Long-term surveillance of dams, tunnels, refuse dumps and other geotechnical works.

Who uses this standard

• Geotechnical and civil engineers specifying or supervising monitoring campaigns.
• Instrumentation contractors and site technicians installing extensometers.
• Engineering consultants evaluating stability and validating designs.
• Researchers and laboratories conducting field tests to derive geotechnical parameters.
• Owners/operators of infrastructure requiring long-term deformation monitoring.

Related standards

• ISO 18674‑1:2015 - General rules for geotechnical monitoring by field instrumentation (normative reference).
• ISO 18674‑3:2016 - Complements Part 2 to determine displacements in any direction.
• The ISO 18674 series provides the structured framework for geotechnical field instrumentation and monitoring.

Keywords: EN ISO 18674-2:2016, extensometers, geotechnical monitoring, measurement of displacements, in‑place extensometer, probe extensometer, tape extensometer, Observational Design, pile load tests, slope stability.