Evaluation of long-term behaviours of geogrids: a review

This study focused on the test method that is used for evaluating the long-term performance of various types of geogrid. The tests were performed using two kinds of geogrid (textile and membrane-drawn). The design strengths of the geogrids used in this study were 8 and 10 t/m, respectively. From the estimated long-term creep deformation, it was seen that 60–65% of the ultimate loading level (T_ult) was the optimum value to satisfy the creep criteria (curve becomes asymptotic to a constant strain line, of 10% or less) in the case of the woven geogrid. These values also indicated that the textile geogrid had strong resistance to long-term deformation compared with the membrane-drawn geogrid. From the outdoor and chemical resistance evaluation, a factor of safety was determined by using the reduction factors of the ultimate strength induction conditions and the long-term design strength was obtained by applying this factor of safety over the design life.