Abstract:
Unsaturated expansive soils are recognized as one of the most
problematic soils owing to its swelling-shrinkage characteristics.
The presence of such soils in highway/railway embankments,
slopes and earthen dam sites manifests various critical issues
during and after the construction of structures. The current
research aims on the evaluation of the suction, swelling and
collapsible characteristics of four expansive soils possessing
different expansiveness and mineralogical composition. A series
of constant volume swell pressure, double-oedometer and incontact filter paper tests were performed on four different
expansive soils to acquire swelling pressure, collapse potential
and matric suction at different degree of saturation. Swelling
pressure, collapse potential and matric suction of all expansive
soils degraded substantially with increment in the degree of
saturation. The results revealed significant impact of magnitude of
matric suction on volumetric deformation (swell and collapse)
behavior of expansive soils. Swelling and collapse potential were
observed to be higher for the expansive soils with larger matric
suction. Higher matric suction governed the water intake within
interlayer spacing of the Montmorillonite mineral present in
expansive soil, which contributed to higher crystalline swelling
response. Larger collapse potential indicated development of
larger localized deformations within the soil mass owing to higher
matric suction
