Performance of embankments with and without reinforcement on soft subsoil

Abstract

A case history of both reinforced and unreinforced embankments on soft subsoil built-to-failure is described and analyzed. The effect of geotextile reinforcements on embankment behavior is discussed by comparing the field and numerical analysis results of cases with and without reinforcement. The results of a laboratory model test on the behavior of embankments on soft subsoil are discussed. Both field and laboratory tests, as well as analysis results, indicate that the reinforcement had a positive effect on embankment stability. However, at a working state (for a factor of safety of FS = 1.2~1.3) the reinforcement did not have an obvious effect on the subsoil response. The effect of reinforcement on subsoil deformation could be noticed only when the unreinforced embankment was close to failure. The laboratory model test results indicated that if the reinforcement is stiff and strong enough, the effect of reinforcement is considerable. It is suggested that although the geotextile has a beneficial effect on embankment over soft subsoil due to its relative lower stiffness, to achieve a substantial improvement on embankment behavior, the stiffer and stronger reinforcements should be used. This case history also demonstrated that the rate of lateral displacement and excess pore pressure development are sensitive indicators of the stability of embankment on soft subsoil.Key words: embankment, reinforcement, soft ground, field tests, laboratory tests, FEM analysis.