Overview
EN ISO 10772:2012 / ISO 10772:2012 specifies a laboratory test method to determine the filtration behaviour of geotextiles under turbulent water flow conditions. It simulates wave action, ship-induced wakes or other turbulent hydraulic loads and measures the amount and rate of soil passing through a geotextile filter. The result is used as a performance measure for designing erosion-protection layers and geotextile filters in hydraulic engineering.
Key topics and requirements
- Purpose: Determine soil passing value (Spv) and assess filtration stability of geotextiles under turbulence.
- Test soil: Dried to constant mass at 105°C. Example grading curve for medium–coarse silt is given in Annex A; undrained cohesion cu ≤ 1.5 kN/m2.
- Specimens & preparation:
- Three specimens, 168 mm diameter, punched from a laboratory sample.
- 1 500 g of test soil placed loosely on each specimen and compacted to exert 2 kN/m2 surface pressure using a 151 mm brass disc (mass 2 130 g).
- Compaction by a vertically oscillating device at 50 Hz and 1.5 mm amplitude for 240 s.
- Specimens saturated in tap water (20°C ± 5°C) for ≥16 h with 20 cm water cover.
- Test apparatus:
- Three-sample test rig with turbulence-producing agitator (four-bladed rotor at 260 rpm producing flow 70–90 cm/s; blade passage frequency ≈17.3 Hz).
- Required accessories include drying oven (105°C ±5°C), electronic balance (0.01 g resolution), hydrophilic folded filter (500 mm, retention 5–13 µm), stainless steel mesh (11 mm), collection vessels (>60 L).
- Procedure & duration:
- Five loading phases, each 30 min (total 150 min). Water refilled between phases.
- Collect and quantify soil passing through the filter by filtration, drying (105°C) and weighing.
- Evaluation:
- Average soil passing for three specimens plotted cumulatively vs. phase.
- Stabilization judged from slope and final-phase values (for the example test soil the last-phase soil passing should not exceed 30 g and total mass not exceed 300 g).
Applications and users
- Applications: Design and verification of geotextile filters in erosion protection, revetments, coastal structures, river and port works where turbulent water and wave action occur.
- Primary users:
- Geotechnical and coastal engineers
- Geosynthetics manufacturers and product developers
- Testing laboratories and conformity assessment bodies
- Contractors and specifiers preparing hydraulic engineering procurement documents
Related standards
- ISO 9862 - Sampling and preparation of test specimens (referenced for sampling).
- ISO 12956 - Determination of characteristic opening size (used for related test equipment).
- ISO/TS standards cited for soil parameter testing (e.g., ISO/TS 17892 series for soil characterization).
Keywords: geotextiles, filtration behaviour, turbulent water flow, ISO 10772, filtration stability, soil passing value, erosion protection, hydraulic engineering.