Reduced scale laboratory physical model for a geotextile reinforced embankment under groundwater flow

Abstract

Geotextiles are used as basal reinforcement for the embankments constructed on soft soil sites as an alternative to the conventional soil improvement techniques. The failure scenarios of geotextile reinforced embankments generally involve bearing capacity, global stability, elastic deformation, pullout and lateral spreading analysis. However, the behavior of geotextile reinforced embankments under seepage flow has not been thoroughly investigated since most design guidelines require a proper drainage system to prevent pore water pressure accumulation within the embankment. This study investigates the behavior of an embankment reinforced by nonwoven geotextile in the case of groundwater flow within the embankment. For this purpose, a laboratory model of a geotextile reinforced embankment with the dimensions of 195 cm long, 100 cm wide, and 110 cm high was constructed. Embankment, comprised of well drained sand, with a side slope angle of 45 degrees was constructed in a controlled manner by performing the compaction in 5 cm lifts to form a uniform domain with a dry density of 14.0 kN/m3. Constant hydraulic head of 100 cm was applied using the water reservoir located behind the model. Vibrating wire pressure cells were used to monitor total pressures during both construction stage and seepage experiment. In addition, pencil size tensiometers and piezometers were used to capture piezometric conditions on the side and within the embankment, respectively. Behavior of the geotextile reinforced embankment under seepage was compared to that of unreinforced (Matrix) embankment under the same hydraulic boundary condition. Due to the limited in-plane drainage capacity (transmissivity), non-woven geotextile reinforcement was not able to alleviate the pore water pressures within the embankment. Therefore, as in the case of Matrix embankment, deep-seated global stability failure starting from the crest and exiting at the toe of the embankment was occurred. Copyright © 11th Inter. Conf. on Geos. 2018, ICG 2018. All rights reserved.