Overview
EN ISO 22282-2:2012 - Geotechnical investigation and testing: Geohydraulic testing - Part 2 - specifies procedures and requirements for determining local water permeability in soils and rocks using water permeability tests carried out in an open borehole (open systems). Intended as part of geotechnical investigation services in accordance with EN 1997-1 and EN 1997-2, this standard covers test principles, equipment, test procedures, result calculation and reporting for permeability measurements above and below the groundwater table.
Key topics and technical requirements
- Test principle: Tests assume an isolated test section in the borehole located either above or below the groundwater surface. Results depend on test type (injection vs withdrawal).
- Three test methods:
- Constant flow rate (for higher permeabilities, e.g. k > 10^-6 m/s): impose a steady flow and record head change vs time.
- Variable head (intermediate k range): induce an instantaneous head change and record head decay vs time.
- Constant head (for lower permeabilities, e.g. k between 10^-7 and 10^-4 m/s): maintain constant head and measure flow vs time.
- Test section preparation:
- Non-stable ground: options include perforated tube with disc, filter pack with withdrawn casing, or open-end test at casing base.
- Stable ground/rock: options include packer isolation, temporary open piezometer with filter pack and sealing plug, or filter-filled test section.
- Unsaturated conditions are covered where applicable.
- Equipment & accuracy:
- Water supply/pump or bail system, flow measurement device (accuracy within 5% of range), flow-controlling device, perforated tube/filter pack, water-level measurement (accuracy 0.01 m), timing/recording devices.
- Calibration of all equipment before or regularly during use is required.
- Reporting and interpretation:
- Standard defines required field and test report contents and includes informative annexes for recording measured values and guidance on interpretation.
Practical applications
- Site characterization for foundation design, earthworks, tunnelling and underground construction where local permeability affects seepage, consolidation and stability.
- Hydrogeological assessments, groundwater inflow estimation, and design of dewatering or grouting programs.
- Quality control during drilling and in-situ testing programs used by consultants, contractors and laboratories.
Who uses this standard
- Geotechnical engineers, hydrogeologists and engineering consultants
- Drilling and in-situ testing contractors
- Geotechnical laboratories and research organizations
- Design teams working to EN 1997 (Eurocode 7) for foundations and underground works
Related standards
- EN ISO 22282-1: General rules (Part 1)
- ISO 22475-1: Sampling and groundwater measurements - Technical principles
- Other parts of ISO 22282 series: Part 3 (rock pressure tests), Part 4 (pumping tests), Part 5 (infiltrometer tests), Part 6 (closed systems)
Keywords: EN ISO 22282-2:2012, water permeability tests, borehole testing, geohydraulic testing, geotechnical investigation, permeability in soils and rocks, open systems.