Overview
EN ISO 22282-6:2012 - "Geotechnical investigation and testing - Geohydraulic testing - Part 6" specifies procedures for performing water permeability tests in a borehole using closed systems. The standard defines how to determine local hydraulic properties in soils and rocks (above or below the groundwater table) as part of geotechnical investigation services referenced in EN 1997-1 and EN 1997-2. Tests are based on applying an instantaneous change in hydraulic head in a sealed borehole interval and recording pressure dissipation with time.
Key topics and technical requirements
- Test principle: closed-system pressure (pulse) test where an isolated test section is subjected to a sudden head change and pressure dissipation Δp(t) is recorded.
- Measured outputs: pressure vs. time curves, variation of volume at pressure application, and system compressibility values used for interpretation.
- Hydraulic parameters: determination of permeability coefficient (k); tests can also be used to estimate transmissivity (T) and storage coefficient (S).
- Equipment: pump or pressure source, pipes and tubing, single/double inflatable packers or sealing plugs, isolating valve(s), pressure and temperature sensors, data acquisition system and volume-measuring device.
- Test execution:
- Install tubing and packers; establish pre-test stabilized hydraulic head (different procedures for below and above groundwater table).
- For unsaturated tests, a saturation phase is required before the pulse application.
- Apply a controlled pressure pulse (limits to avoid hydraulic fracturing) and record pressure at high frequency (the standard notes measurements every second).
- Record initial and final compressibility checks and log ΔV/Δp for the system.
- Reporting: detailed field and test reports are required, including equipment, test geometry, borehole data, groundwater level, test pressure-time records, saturation duration (if applicable), and operator details.
Applications and users
- Practical uses: site investigation for foundation design, underground works, earthworks, groundwater flow characterization, and input to geotechnical design calculations where local permeability of low-permeability soils or rock is critical.
- Typical users: geotechnical engineers, hydrogeologists, site investigation contractors, geotechnical laboratories, consultants and regulatory authorities involved in geohydraulic testing and subsurface characterization.
Related standards (if applicable)
- ISO 22282 series (Part 1: General rules; Part 2: open systems; Part 3: water pressure tests in rock; Part 4: pumping tests; Part 5: infiltrometer tests)
- ISO 22475-1 (sampling and groundwater measurements)
- ISO 14688-1, ISO 14689-1 (soil and rock identification/classification)
- EN 1997‑1 / EN 1997‑2 (geotechnical design and investigation requirements)
Keywords: geotechnical investigation, water permeability tests, closed systems, borehole testing, permeability coefficient, transmissivity, EN ISO 22282-6:2012, geohydraulic testing.
