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