Geosynthetic-reinforced embankments over soft foundations

Abstract

The behaviour of reinforced embankments over conventional soft cohesive soil, rate-sensitive soil and peat deposits is reviewed, and recent design and analysis methods are summarized. The findings from both field observations and finite element analyses are presented. Both undrained and partially drained behaviour of reinforced embankments are considered. The use of reinforcement in combination with prefabricated vertical drains is addressed. The effects of both the viscous and inviscous characteristics of reinforcement and foundation soils on embankment behaviour are discussed. It is concluded that the partial consolidation provided by PVDs and the tension mobilized in reinforcement can substantially increase embankment stability. However, creep of geosynthetics can decrease the embankment failure height. The mobilization of reinforcement during and after embankment construction can vary significantly depending on the soil and reinforcement characteristics. Care must be taken in design when a creep-susceptible reinforcement is being used and/or the foundation soil is rate sensitive. Note: This paper is a slightly modified version of the Giroud Lecture presented by R. K. Rowe at the Seventh International Conference on Geosynthetics in Nice, France, in 2002.