Overview
EN ISO 22476-5:2023 - Geotechnical investigation and testing - Field testing - Part 5: Prebored pressuremeter test (ISO 22476-5:2023) - defines procedures for in‑situ pressuremeter testing using cylindrical flexible probes installed in pre‑existing boreholes. The standard covers equipment, calibration, test execution, data correction, result interpretation and reporting for prebored pressuremeter tests (distinct from the Menard procedure, which is covered in ISO 22476-4). It applies to tests on all ground types - from soft soils and fills to hard rocks - and is suitable for both onshore and offshore investigations.
Key topics and requirements
- Scope and applicability: tests with flexible pressuremeter probes in prebored holes; applicable across soils, treated fills, hard/soft rocks, land and offshore.
- Equipment: requirements for the probe, connecting lines, control unit (CU), and measurement accuracy (pressure, displacement/volume, time).
- Calibration and corrections: procedures for calibrating expansion and pressure measurements and applying corrections to raw readings.
- Test procedures: assembly, placing the probe in the test pocket, defined loading programmes (including newly added cyclic loading option), reference loading sequences, readout and recording protocols, end‑of‑test and borehole backfilling.
- Data and results: calculating corrected pressure, radial displacement and volume; deriving apparent pressuremeter moduli; determining stiffness, strength, in‑situ stress and consolidation properties.
- Reporting and quality: required content and presentation of test reports, accuracy/uncertainty considerations and safety requirements during field operations.
Applications and practical value
- Derives engineering parameters used in foundation design, retaining structures, tunnel and shaft design, slope stability and offshore foundation assessment.
- Provides reliable in‑situ measurements of stiffness, strength, initial in‑situ stress state and consolidation properties that complement laboratory tests and other field tests (e.g., CPT, SPT).
- Useful for site characterization where boreholes exist and where a non‑Menard prebored pressuremeter method is preferred (e.g., probes with radial displacement transducers - also called high‑pressure dilatometers).
Who should use this standard
- Geotechnical engineers and consultants performing site investigations
- Drilling contractors and testing crews conducting pressuremeter testing
- Geotechnical laboratories and research organizations analyzing in‑situ test data
- Regulators and clients requiring standardized field testing and reporting for design and conformity
Related standards
- ISO 22476-4 (Menard pressuremeter procedure)
- ISO 22475-1 (sampling and groundwater measurement principles)
- ISO 14689 (rock description and classification)
- ISO 10012 (measurement management systems)
- EN 16228 series (drilling equipment safety)
Keywords: geotechnical investigation, prebored pressuremeter test, ISO 22476-5, pressuremeter probe, field testing, in-situ testing, stiffness, strength, consolidation properties.