Ten year creep puncture study of HDPE geomembranes protected by needle-punched nonwoven geotextiles

The need for a geotextile to be used for protection against geomembrane puncture by stones and gravel has been recognized for many years. There are presently several methods available for selecting such geotextiles. This paper, however, focuses on the “GRI-Method”, which was originally based on short-term tests and was extended empirically for long-term performance. The reduction factor for creep behavior (RFCR) is of particular interest since its impact on the resulting geotextile design is the greatest.The paper presents results of a 10-year long creep puncture study which is configured exactly the same as was the original short-term testing program. The results indicate that the six ≈38 mm high puncturing cones result in yield of the geomembrane at pressures of 34 and 52 kPa and one even had a small break. The six 12 mm high cones at pressures of 430 and 580 kPa also resulted in geomembrane yield but only by a nominal amount and there were no breaks.As a consequence of these creep test results, the original table for creep reduction factors (RFCR) has been revised into more conservative values. In this regard, the originally published RFCR table should be replaced accordingly.