In a recent project I-CORP was asked to propose the maximum allowable strains in HDPE (smooth, textured, structured), LLDPE, and fPP geomembranes that might be used in a separation layer for a vertical expansion of a landfill. The request was instigated by a regulator’s implication that a maximum of 1% would be required. This clearly makes design very complex. After due considerations of the confining environment, stress cracking resistance, stress relaxation, and other phenomena the following figures, thought by some to be conservative, have been recommended:

Recommended maximum allowable strains are as follows:

Smooth HDPE, SCR >1500 hr 8%

Smooth HDPE, SCR <1500 hr 6%

Structured HDPE 6%

Random textured HDPE 4%

LLDPE, density <0.935 g/cm3 12%

LLDPE, density >0.935 g/cm3 10%

Structured LLDPE 10%

Textured LLDPE 8%

PP (unreinforced) 15%

Taken from abstract title: Maximum Allowable Strains in HDPE, LLDPE, and PP Geomembranes Used in the Separation Barrier Layer of a Landfill Vertical Expansion
Authors :
Ian D. Peggs, I-CORP INTERNATIONAL 561-272-1312, 561-272-8131 (fax)icorp@geosynthetic.com,
Bruce Schmucker Emcon/OWT, Inc. 513-782-4756 Bruce.Schmucker@theitgroup.com,
Peter Carey PJ Carey Associates 678-482-5193, 678-482-5827 (fax) pjcarey@mindspring.com

Note that these figures only apply to geomembranes in a confined situation. They should not be used for geomembranes under a constant stress in unconfined circumstances.

A detailed paper presenting supporting arguments for these figures has been submitted for presentation at the EuroGeo 3 conference in Munich in 2004.

For further information contact icorp@geosynthetic.com.

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