Deformation performance and stability control of embankments on peat soils

Abstract

Embankments constructed on very soft soils such as peat are frequently controlled by means of an observational method approach. Concurrent observations of maximum settlement and maximum lateral movement of the soil profile at the embankment toe can be used to calculate a deformation ratio which varies with load application and can be interpreted as an indicator of stability. Trigger or threshold values have been suggested for single stage embankments constructed on soft mineral soils, but little guidance is available for multi-stage embankments on organic, peat soils. This research is a compilation of analysis of several published international case histories involving instrumented embankments and load tests constructed on peat soils. Suggested limits for threshold values are developed for deformation ratios and shear strain rate. Recommendations for instrumentation layout, monitoring frequencies, data interpretation are developed. The goal of the paper is to summarise published experience and provide guidance to practitioners using the observational method to control stability of embankments on very soft peat soils.