ABSTRACT
A suitable behaviour of backfill/geosynthetic interfaces is one of the key points to achieve a good performance of any geosynthetic reinforced structure. Previous researches have been showing that the interfaces between recycled construction and demolition (C&D) wastes and some geosynthetics have coefficients of interaction in the range of usual values for soil/geosynthetic interfaces. However, most of these studies only evaluated the geosynthetics pullout resistance under monotonic loading conditions (constant displacement or load rates during pullout) and do not consider their long-term behaviour. This paper presents a preliminary laboratory study conducted to investigate the effects of multistage loading on a geogrid pullout behaviour. After reaching a predefined value (40% or 70% of the geogrid pullout resistance) under load-controlled conditions, the pullout force was kept constant for 30 or 120 minutes and then increased until the geogrid pullout failure. The results obtained to date show that sustained loads periods did not reduced the geogrid pullout resistance and thus the usual pullout tests are on the safety side. The duration of the sustained load stage affected mainly the cumulative deformations on the geogrid, which are more significant when the constant load level is closer to the geogrid’s pullout resistance.
