Webinar Description

The use of heavy weight nonwoven geotextiles as a protection / Cushion layer between drainage aggregate and the relatively thin HDPE geomembrane at the base of a waste containment facility is the norm in most lining applications. When these systems were first applied the role of the geotextile was to provide puncture /rupture protection. However as our understanding of the long term performance of HDPE has increased limiting strain in the geomembrane to relatively low numbers has become the key to a best practice design. The concept behind lowering the strains developed in the geomembrane to well below the puncture point, is to limit/remove the potential for stress cracking in the geomembrane.

The accurate measurement of the strains developed in the geomembrane therefore becomes critical in terms of the design of a suitable cushion geotextile. A number of different test methods for strain measurement are available to the design engineer, however a good understanding of these methods and how the reported strain values are derived is critical in developing a robust design.

This webinar covers the following

1. A short history of geotextile liner protection both locally and internationally
2. The test methods currently used in industry and the influence these methods have on strains developed
3. The method of strain measurement applied to each standard
4. The stress strain characteristics of a HDPE geomembrane
5. Recommendations on setting up a cushion test program
6. Recommendations of allowable strain values for the different test methods