Flexible Wall Permeability Soil Test Systems

Hydraulic conductivity or flexible-wall permeability testing determines flow characteristics of water or other permeant fluids through soils, and is frequently used to asses natural soils, fills, or clay liners in environmental applications.


Testing involves preparing and mounting undisturbed or remolded soil specimens in a Test Chamber pressurized with water to create a confining pressure around the specimen. The test is designed to be run on water-saturated soil samples containing virtually no air, at a controlled level of effective stress. The flexible wall, a latex membrane, allows control of effective stress and prevents fluid exchange between the specimen and pressurized water in the chamber.

The Control Panels use the Testing Chambers to control the air and fluid pressures through a system of burettes, valves and regulators, and are a central point for supply connections of air, water, and drains. These same Control Panels are also used for Triaxial testing applications.

The Latex Membranes are used to surround the specimens in the Test Chambers to shelter them from the water during testing and when the Membrane Stretchers are installed.  The O-rings are placed around the speciman caps using the Placing Tool to close the membrane ends, and Porous Stones are placed at ends of each specimen to protect it during testing while still allowing water to pass through.