HYDRAULIC PROPERTIES TESTS

  • WATER PERMEABILITY
    NORMAL TO THE PLANE

    Test performed according to EN ISO 11058.

    A minimum of 5 circular specimens 100 mm in diameter are cut and placed in water with surfactant solution for a minimum period of 12 hours. Soaked sample is placed in water-filled permeameter and de-aired (air bubbles are removed). A hydraulic head is adjusted to 50 mm and sample is permeated with de-aired water. The rate of flow through sample is determined based on volume or mass of water collected in not less than 30 s. The result of the test if the average flow rate measured on at least 5 specimens.

  • IN-PLANE FLOW CAPACITY

    Test performed according to EN ISO 12958.

    A minimum of 3 rectangular specimens (100x200 mm) are cut in machine direction and cross machine direction and thickness under 2 kPa load is determined. Specimens are placed in water with surfactant solution for a minimum period of 12 hours. Soaked specimen is mounted in the transmissivity unit between two rigid plates, two soft plates or soft and rigid plate depending on the expected application of the product.

    A seating pressure of 2 kPa is applied and specimen is de-aired. A normal pressure of 20 kPa is set on the sample and a hydraulic gradient of 0,1 is applied. The rate of flow through sample is determined based on volume or mass of collected water. After three measurements of flow the hydraulic gradient is increased to 1,0. The test is carried out under 20, 100 and 200 kPa normal pressures using both 0,1 and 1,0 hydraulic gradient. An average of at least three measurements of in-plane flow capacity, under given load and hydraulic conditions, is reported as test result.

  • WATER FLUX INDEX OF A GEOSYNTHETIC CLAY BARRIER (GCL)

    Test performed according to EN 16416.

    A circular 100 mm specimen is cut using a puncher die. Edges of the specimen are moistened to prevent bentonite loss during specimen cutting. The specimen is placed between two filter papers and porous stones and mounted in a triaxial cell that is filled with water.

    The cell pressure is set to 105 kPa and sample backpressure is set to 70 kPa. Specimen is saturated and flushed. The cell pressure is gradually increased to 550 kPa while the backpressure is increased to 515 kPa. The effective pressure on the sample is equal to 35 kPa and constant through the saturation, consolidation and test period. A hydraulic head of 150 cm is applied to the specimen and the flow through specimen is measured until min. 4 stable measurements are recorded.

    The result of the test is the average index flux calculated from a minimum of 4 stable measurements.