Protection geomembrane liners in landfills is critically important for the calculation of the service life of the liner system. Typical designs for basal containment systems use a coarse aggregate leachate drainage layer over the geomembrane liner, with a cushioning geotextile separating the two. The uneven surface of the drainage layer creates localised point loads on the geomembrane; these stress points can lead to long term environmental stress cracking of the geomembrane and in turn increase leakage from the landfill. The geotextile, typically a densely needle-punched non-woven, plays a crucial role in limiting the development of local stresses within the liner.  Understanding the performance of the geotextile protection relative to the particle size, angularity and imposed load from the overlying drainage aggregate is critical to determining the suitability of any given protection layer.

Testing of the performance of the geotextile protection layers is carried out using ASTM D5514 apparatus and laser scanning techniques to determine the linear and bending strains developed in the liner system.