SIST EN ISO 14688-2:2018 PDF

Overview

EN ISO 14688-2:2018 - Geotechnical investigation and testing: Identification and classification of soil - Part 2: Principles for a classification (ISO 14688-2:2017) defines the fundamental principles for grouping soils by composition and geotechnical behaviour. Intended to be read with ISO 14688‑1 (identification and description), this CEN-adopted standard applies to natural soils in situ, reworked soils and synthetic materials and supports consistent soil classification for design, construction and investigation.

Key topics

The standard establishes classification principles based on commonly used material characteristics and laboratory/field test results. Primary technical topics and requirements include:

• Particle size fractions and particle size distribution (grading) - criteria for describing coarse and fine fractions and grading behaviour.
• Plasticity - use of Atterberg limits (liquid and plastic limits) and derived indices (consistency/index parameters) to characterise fine-grained soils.
• Organic and carbonate content - recognition of how organics and carbonates affect engineering properties and classification.
• Other geotechnical parameters useful for classification, such as relative density (density index) correlations for coarse soils, undrained shear strength for fine soils, sensitivity and other consistency measures.
• Guidance on combining field observations and ISO laboratory methods (see ISO 17892 series) to form robust classification groups.
• Emphasis on flexibility: local geological conditions and project-specific needs may require more detailed subdivisions or enhanced criteria.

Applications

EN ISO 14688-2:2018 is used to:

• Provide a consistent basis for geotechnical site investigation reports and soil databases.
• Support foundation design, earthworks, tunnelling and underground construction through reliable soil grouping.
• Inform testing programs and laboratory reporting (linking identification rules from ISO 14688‑1 to classification principles).
• Aid procurement, specification and quality control for contractors and testing laboratories.

Who uses this standard

Typical users include:

• Geotechnical and civil engineers
• Ground investigation consultants
• Geology and soil testing laboratories
• Contractors performing earthworks and foundation works
• Regulators and standards bodies

Related standards

Relevant documents to consult alongside EN ISO 14688-2:2018:

• ISO 14688‑1 - Identification and description of soils
• ISO 14689 - Identification and description of rock
• EN 16907‑2 - Detailed classification for earthworks
• ISO 17892 series - Laboratory testing methods (water content, particle size distribution, Atterberg limits, etc.)
• ISO 25177 - Soil classification for pedological and remediation contexts

Using EN ISO 14688-2:2018 ensures consistent, transparent soil classification practices essential for reliable geotechnical engineering and construction decision-making.