An optimized method to measure the hydraulic conductivity of geosynthetics under load

The hydraulic conductivity is a major factor in selecting an appropriate geosynthetic filter. This paper describes a method for determining the hydraulic conductivity of geosynthetics normal to the plane, when subjected to normal compressive stress. A new apparatus to test transmissivity under load, permittivity without load, and permittivity under load is introduced. The study focuses on the optimization of the permeameter, the filter plates and the procedure to test the permeability under load. Due to the hydrodynamic resistance of the test device, the head loss over the geosynthetic cannot be measured directly, but has to be assessed by recording a calibration curve of the device, and subtracting the data from the values measured with the geosynthetic. It could be shown that turbulent flow cannot be neglected when evaluating the test results, which poses no problems as long as quadratic interpolations for the head loss versus the flow rate are applied.