Abstract: As pivotal technical indicators in designing geosynthetic and reinforced soil structures, the properties of interface between soil and reinforcement reveal the reinforcement mechanism of geosynthetics. In the present study, the influences of shear rate, vertical stress, and geogrid's mesh size on the performance of interface between geogrid and saturated fine sand were investigated using GDS interface shear apparatus.Results revealed that 1) Small shear rate (≤1.0 mm/min) had only slight impact on the shear strength of interface. 2) When shear rate ranged between 1.0 and 10 mm/min, the shear strength of interface increased initially but decreased afterwards with the growth of shear rate. 3) The rising of vertical stress enhanced the shear strength of interface by intensifying the interlocking effect of geogrid on soil particles and limiting the shear displacement of soil particles. 4) When shear rate was 1.0 mm/min and vertical stress was small (50-100 kPa), geogrid with small mesh size was more effective in reinforcement; when shear rate was 0.1 mm/min and vertical stress was large (200-300 kPa), geogrid with large mesh size was of better reinforcement effect. The results can facilitate the application of geogrids in reinforced soil.

Key words: geogrid, saturated fine sand, interface properties, interface shear test, shear rate, mesh size