DURHAM

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• DURHAM
• UNIVERSITY
• LABORATORY TESTING
• (and a contribution to
• field measurements)
• David Toll

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Objectives

• To determine soil water retention curves
  (relationship between water content and suction)
  for embankment fill material
• To determine strength and stiffness of the fill
  in various compacted states with know suctions
• As compacted
• Wetted dried from the compacted state
• To determine saturated permeability
• To measure suctions insitu in the embankment

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Particle Size Distribution
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Classification/Permeability

• Classification
• Clay content 23 Fines content 77
• wL 43 wP 24 IP 19 IL -0.05
• CLAY of intermediate plasticity
• Saturated permeability measured in triaxial cell
• k 1.4 x 10-12 m/s

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Compacted Densities
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Triaxial Testing
Double-walled Triaxial Cell
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Field measurements
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Triaxial Testing (as compacted)

• Compact samples
• Measure initial suction (Axis translation or
  suction probe)
• Consolidate to known net stresses
• Shear to determine stiffness and strength

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Triaxial Testing (wetting/drying)

• Compact samples
• Measure initial suction
• Wet/dry to required water content and measure new
  suction
• Consolidate
• Shear