Analysis of Strain Concentration Next to Geomembrane Seams

Polyethylene geomembranes which are subjected to excessive tensile strains often fail next to seams. The analysis presented in this paper shows that strain concentration due to geomembrane bending in the vicinity of seams may play a significant role in geomembrane failures which occur next to seams. This is one of the many practical conclusions of this paper, which presents a theoretical analysis of strain concentration in geomembranes that result from the presence of seams. It is shown that maximum strain concentration occurs next to the seams when geomembranes are subjected to tensile strain, regardless of the causes of the tensile strain, such as: applied forces, geomembrane thermal contraction, and geomembrane irreversible shrinkage. Calculations performed for typical seams show that the strain in the geomembrane next to a seam can be more than twice as large as the average tensile strain in the geomembrane. A geomembrane embrittled by low temperature, or for other reasons, may not be able to withstand such strain. A parametric study presented in this paper indicates the influence of seam type and geometry on the magnitude of strain. A comparison of the seams typically used for polyethylene geomembranes indicates that fusion seams tend to cause less strain concentrations than extrusion seams.