Compacted soil behaviour through changes of density, suction, and stiffness of soils with remoulding water content

For better understanding the overall hydro-mechanical behavior of interlayer soil, the compaction behaviour of one of the two components - the portion of fines (< 4 mm) that is sensitive to water content changes was investigated. The standard Proctor compaction curves were first determined for the soils. Then, the maximum shear modulus Gmax and suction were measured on samples statically compacted at an identical dry density but different remoulding water contents. The changes in Gmax reveal the existence of a characteristic water content corresponding to the maximum Gmax. The results also show that this characteristic water content increases with the soil plasticity, being similar to the variation trend of optimum water content with soil plasticity. A bimodal pattern was observed from the plot of total suction ψ versus the slope of water content w – log(ψ) curve. The suction corresponding to the maximum Gmax is close to the lowest point between the two peaks in the ψ - dw/dlog(ψ) curve. A reasonable expl...