ISO 22476-5:2023

Overview

ISO 22476-5:2023 - "Geotechnical investigation and testing - Field testing - Part 5: Prebored pressuremeter test" - specifies requirements for performing prebored pressuremeter tests using cylindrical flexible probes in existing boreholes (excluding the Menard procedure covered by ISO 22476-4). It covers tests on all ground types - from fills and soft soils to hard and very hard rocks - and applies to land and offshore investigations. The standard also recognises high‑pressure flexible probes with radial transducers as flexible dilatometer probes or high‑pressure dilatometers.

Key topics and technical requirements

• Scope and definitions: Clear terminology for pressuremeter probe, test pocket, seating pressure, radial displacement, pressuremeter curve, etc.
• Equipment: Requirements for probe design, connecting lines and the pressuremeter control unit (CU), including measurement and control accuracy for pressure, expansion and timing.
• Calibration and corrections: Procedures for calibrating equipment (expansion calibration cylinder) and applying corrections to raw readings to obtain corrected pressure, radial displacement and volume.
• Test procedures: Guidance on assembly, pocket formation in prebored holes, probe placement, and execution of loading programmes (including reference loading programmes A, B and C and a newly added cyclic loading programme).
• Data and results: How to derive parameters from pressuremeter curves - e.g. apparent pressuremeter moduli, pressuremeter shear modulus, in‑situ stress indications, stiffness and consolidation behavior.
• Reporting and safety: Prescribed content and presentation for test reports, plus safety and backfilling requirements.
• Supporting annexes: Normative annexes on calibration/corrections and accuracy/uncertainties, and an informative annex on performing the test.

Practical applications and intended users

ISO 22476-5:2023 is intended for professionals involved in geotechnical site characterization and foundation design:

• Geotechnical engineers and consultants using pressuremeter data for bearing capacity, settlement and stiffness estimates.
• Site investigation teams and drilling contractors conducting prebored pressuremeter soundings.
• Offshore engineers assessing seabed stiffness and strength for pipelines, jackets and foundations.
• Researchers and laboratories validating pressuremeter instrumentation and test methods. Typical uses include foundation and pile design, slope stability assessment, tunnel and retaining structure design, and evaluation of consolidation or in‑situ stress conditions.

Related standards

• ISO 22476-4 (Menard pressuremeter procedure)
• ISO 22475-1 (sampling / groundwater)
• ISO 14689 (rock description/classification)
• ISO 10012 (measurement management)
• EN 16228 series (drilling equipment safety)

Keywords: ISO 22476-5:2023, prebored pressuremeter test, pressuremeter, flexible dilatometer probe, geotechnical investigation, field testing, pressuremeter curve, in‑situ stress, stiffness, calibration.