The effect of compaction conditions on the soil water retention behaviour of a compacted glacial till

An instrumented embankment has been established at Nafferton farm in North East England to investigate the response of an embankment to changing climatic conditions. The embankment was constructed using Durham Lower Glacial Till as the fill material. Soil water retention curves for the embankment soil have been measured in the laboratory using novel high suction tensiometer based equipment that can continuously measure water content, suction and volume change. A suite of soil water retention curves have been measured with a range of techniques, using filter paper, chilled-mirror hygrometer and including the new Durham SWRC apparatus. Good agreement can be seen from the different methods, defining a consistent “primary drying curve”. The paper presents results for specimens compacted wet of optimum water content (gravimetric water content near 25%) and at the water content used for field compaction (gravimetric water content of 20%). Specimens compacted near saturation define a clear primary drying curve. Specimens compacted at the field water content show a flatter response, joining the primary drying curve as suction increases.