Large-Scale Quantification of Wrinkles in a Smooth Black HDPE Geomembrane

Wrinkles are buckles or waves that develop from restrained thermal expansion when the geomembrane is left exposed to solar heating. Wrinkles can substantially reduce the effectiveness of the geomembrane as a hydraulic barrier if a hole is at or near a wrinkle, depending on the number, length, and width of wrinkles. Low altitude aerial photography and digital image analysis are used to quantify the nature and extent of wrinkles that developed over one hot and sunny day in a smooth, black, 1.5-mm-thick high-density polyethylene (HDPE) geomembrane over a 55 m by 140 m area. Wrinkles were found to significantly vary over the course of the day, increasing from the fewest wrinkles in the morning to a maximum just after noon before decreasing toward the late afternoon. For the specific conditions examined, wrinkles were found to occupy 3%, 21%, and 7% of the entire area surveyed at 8:45, 12:25, and 17:15, respectively. Connections between adjacent wrinkles were observed to create significant interconnected wrinkle features greater than 2,000 m long. The shortest maximum interconnected wrinkle feature of 80 m/ha was measured at 8:45 while the longest such feature was 6; 600 m/ha at 13:45. The observations and results provide data to support the approach that limiting the time of day when cover is placed on geomembrane can be effective at reducing the extent of wrinkling. DOI:10.1061/(ASCE)GT.1943-5606.0000643. (C) 2012 American Society of Civil Engineers.