EN ISO 22476-9:2020 PDF

Overview

EN ISO 22476-9:2020 - Geotechnical investigation and testing - Field testing - Part 9: Field vane test (FVT and FVT‑F) defines requirements for performing field vane tests to determine vane shear strength of fine‑grained soils. The standard covers equipment, test configurations, execution, measurement, calibration, result calculation and reporting for both the ordinary field vane test (FVT) and the fast field vane test (FVT‑F). It applies to onshore and nearshore testing and supports compliance with geotechnical investigation requirements in EN 1997‑1 and EN 1997‑2.

Key topics and requirements

• Scope and applicability: Measurement of peak and remoulded vane shear strength, soil sensitivity, and evaluation of post‑peak shear behaviour in predominantly fine‑grained (typically saturated) soils.
• Equipment and configurations: Specifications for vanes, vane shafts, friction reducers, slip couplings, extension rods, protective casings, rotation units and torque/rotation measuring devices. Selection guidance for test configurations (borehole, trial pit, pushed‑in equipment) is provided.
• Test procedure: Pre‑test equipment checks and calibrations, depth and insertion methods, internal/external friction torque readings, rotation/torque measurement during shear, and post‑test checks.
• Data, calculation and reporting: How to derive shear strengths from measured torque and vane geometry, presentation of test plots, and minimum reporting content (site location, equipment, procedure, results).
• Uncertainty and interpretation: Annex D describes uncertainties associated with vane test results; other annexes give maintenance/calibration guidance, example field reports, and interpretation notes for differing vane geometries and inclined tests.
• Two test types: Ordinary FVT and fast FVT‑F are described, allowing selection based on project needs.

Applications

• Determination of undrained shear strength for foundation design, slope stability, and earthworks in fine‑grained soils.
• Assessment of soil sensitivity by comparing peak and remoulded strengths.
• Rapid in‑situ evaluations in boreholes, trial pits or pushed probes where laboratory sampling is limited.
• Nearshore and onshore projects where on‑site shear strength and post‑peak behaviour are needed for geotechnical analysis.

Who uses this standard

• Geotechnical engineers and site investigation teams
• Geotechnical consultants and contractors performing in‑situ testing
• Laboratories and equipment manufacturers (for calibration and design)
• Regulators and project owners requiring standardized reporting and conformity with EN 1997 series

Related standards

• EN 1997‑1 / EN 1997‑2 (Eurocode 7 requirements for geotechnical investigation and testing)
• Other parts of the ISO 22476 series covering complementary field tests

Keywords: EN ISO 22476-9:2020, field vane test, FVT, FVT-F, vane shear strength, geotechnical investigation, fine-grained soils, undrained shear strength, soil sensitivity, field testing, onshore, nearshore.