Relationship between NP GCL Internal and HDPE GMX/NP GCL Interface Shear Strengths

Patrick Joseph Fox, Jason D. Ross

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


An investigation was conducted on the relationship between the internal shear strength of hydrated needle-punched (NP) geosynthetic clay liners (GCLs) and the interface shear strength between hydrated NP GCLs (nonwoven side) and high-density polyethylene (HDPE) textured geomembranes (GMXs). New large-scale direct shear data are presented and compared to previous results obtained using similar materials and procedures. The data indicate that both GCLs and GMX/GCL interfaces display large postpeak strength reduction, even at high normal stress. Peak and large-displacement failure envelopes are nonlinear; except for the GCL internal residual strength envelope, which passes through the origin and has a friction angle of 4.8° GMX/GCL interfaces can be expected to have lower peak strengths and higher large-displacement strengths than GCL internal shear specimens. However, the failure mode for GMX/GCL specimens can change from interface shear to GCL internal shear as normal stress increases. Design for peak strength conditions should be based on the lowest peak strength interface in a liner system, and design for large displacement conditions should be on the basis of the residual strength of the same interface.

Original languageEnglish (US)
Pages (from-to)743-753
Number of pages11
JournalJournal of Geotechnical and Geoenvironmental Engineering
Issue number8
StatePublished - Aug 3 2011

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Environmental Science(all)


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