Field and laboratory time-dependent behaviors of geotextiles in reinforced soil walls

Laboratory and field investigation of time-dependent behavior of geotextiles reinforcing a fine-grained soil are evaluated herein. The field assessment consisted of analyses of two instrumented sections of a geotextile reinforced soil wall with identical layouts, including one section with a woven and another with a nonwoven geotextile. In addition, in-soil and in-isolation laboratory creep tests were conducted using the same geosynthetics and soil used in the Geosynthetic-Reinforced Soil (GRS) wall sections to better assess time-dependent behaviors in the field. Construction and time-dependent behavior of the full-scale GRS wall proved to be satisfactory over the 4 years of monitoring of both woven and nonwoven geotextile structures. Soil confinement, due to vertical earth pressure on the reinforcement, was found to greatly affect the deformability of the nonwoven geotextile and to have a minor effect on the woven geotextile. Time-dependent strain rates were higher when the failure stress state of the soil was reached. Under lower vertical stresses, the time-dependent behavior of both geosynthetics was similar. Time-dependent behavior was underestimated from in-soil laboratory creep tests and better estimated using in-isolation laboratory tests. However, the GRS wall data did not account for installation damage and wetting-drying processes, which were found to influence time-dependent strain predictions.