Abstract

Overview

EN ISO 17892-8:2018 - Geotechnical investigation and testing - Laboratory testing of soil - Part 8: Unconsolidated undrained triaxial test (ISO 17892-8:2018) specifies a standardized method for performing unconsolidated undrained triaxial compression tests in the laboratory. The standard covers test objectives, specimen preparation, apparatus requirements, test procedure, result calculation and reporting. It is intended for the laboratory determination of undrained triaxial shear strength and stress–strain behaviour expressed in terms of total stresses and fulfils requirements of EN 1997‑1 and EN 1997‑2.

Key topics and technical requirements

Scope and specimen types: Applies to cylindrical specimens that may be undisturbed, re‑compacted, remoulded or reconstituted soils tested under isotropic confining stress and undrained shearing.
Test principle: Specimen is subjected to a cell (isotropic) pressure under undrained conditions, then sheared axially under undrained conditions to determine deviator stress and undrained shear strength (defined as half the deviator stress at failure).
Failure criteria: Peak deviator stress or a specified deformation limit (e.g., 15% vertical strain) if a peak is not reached.
Excluded procedures: Tests involving pore‑pressure measurement or filter drains are explicitly not covered by this part.
Apparatus, calibration and maintenance: Detailed apparatus requirements and routine checks are specified (see Annex A). Includes guidance on membranes, load measurement, and correction for membrane effects.
Results and reporting: Procedures for calculating corrected cross‑sectional area, deviator stress, vertical strain, volumetric change and undrained shear strength, plus mandatory and optional report items.

Practical applications

EN ISO 17892-8:2018 is used to obtain reliable undrained shear strength and stress–strain data for:

Foundation design and bearing capacity assessments
Slope stability and earthworks analyses
Design and verification of embankments, retaining structures and underground works
Site investigation reports and laboratory testing programs supporting Eurocode geotechnical design (EN 1997 series) The test is particularly relevant for saturated, low‑permeability soils (clays and silty clays) where undrained behaviour governs short‑term response.

Who should use this standard

Geotechnical engineers and consultants
Soil mechanics and laboratory technicians
Researchers and academics in geotechnical testing
Civil engineers preparing Eurocode‑compliant designs
Standards committees and quality assurance personnel in testing laboratories

Related standards

ISO 17892-1 (water content), ISO 17892-2 (bulk density), ISO 17892-3 (particle density)
ISO 14688-1 (soil identification and description)
EN 1997‑1 / EN 1997‑2 (geotechnical design / investigations)

Keywords: EN ISO 17892-8:2018, unconsolidated undrained triaxial test, triaxial compression test, undrained shear strength, laboratory testing of soil, geotechnical investigation.

SIST EN ISO 17892-8:2018 PDF

Похожие стандарты

Abstract

Overview

Key topics and technical requirements

Practical applications

Who should use this standard

Related standards

Технические детали

ISO 17892-8:2018

Geotechnical investigation and testing — Laboratory testing of soil — Part 8: Unconsolidated undrained triaxi…

ISO 17892-1:2014/Amd 1:2022

Geotechnical investigation and testing — Laboratory testing of soil — Part 1: Determination of water content…

BS EN ISO 17892-2:2014

Geotechnical investigation and testing. Laboratory testing of soil. Determination of bulk density.

SIST EN ISO 17892-3:2016

Geotechnical investigation and testing - Laboratory testing of soil - Part 3: Determination of particle densi…

SIST EN ISO 14688-1:2018

Geotechnical investigation and testing - Identification and classification of soil - Part 1: Identification a…