ABSTRACT
As part of large-scale field tests, a range of twelve mechanically bonded nonwoven geotextiles from three manufacturers made of polypropylene staple fibres were tested about their robustness against installation loading in their function as separation layers between soft subsoil and coarse-grained base course material ranging from round-grained, sandy gravel to sharp-edged, stony gravel were used for this purpose. Four different installation situations were simulated. The impact by site traffic was controlled based on the ruts resulting from truck crossings. A suction excavator was used to gently reveal the geotextiles.
All samples were visually assessed for damage and then classified. The energy absorption and the derived damaging work were used to evaluate the mechanical changes based on both, wide-width tensile tests and static puncture tests. Half of the exposed samples remained with more than 80% of their original performance. Almost all materials didn’t exceed 50% of performance loss after the tests. A classification system should quantify the complexity of the soil-geosynthetic-system for separators. The tests have shown that strength alone is not enough to assess them and to avoid damage. The evasion principle should be followed instead. For this purpose, it is necessary to consider the deformability. The energy absorption together with the minimum elongation ability provides a good basis for this. Against this background, a proposal for an update of the current classification system was made.
