Normal Consolidation - The condition that exists if a soil deposit has never
been subjected to an effective stress greater than the existing overburden
pressure and if the deposit is completely consolidated under the existing
Overconsolidation - The condition that exists if a soil deposit has been
subjected to an effective stress greater than the existing overburden
Piezometer - A device installed for measuring the pressure head of pore
water at a specific point within the soil mass.
Piping - The movement of soil particles as the result of unbalanced seepage
forces produced by percolating water, leading to the development of boils or
Plastic Equilibrium - The state of stress of a soil mass that has been
loaded and deformed to such an extent that its ultimate shearing resistance
is mobilized at one or more points.
Positive Cutoff - The provision of a line of tight sheeting or a barrier of
impervious material extending downward to an essentially impervious lower
boundary to intercept completely the path of subsurface seepage.
Primary Consolidation - The compression of the soil under load that occurs
while excess pore pressures dissipate with time.
Rippability - The characteristic of dense and rocky soils that can be
excavated without blasting after ripping with a rock rake or ripper.
Slickensides - Surfaces with a soil mass which have been smoothed and
striated by shear movements on these surfaces.
Standard Penetration Resistance - The number of blows of a 140-pound hammer,
falling 30 inches, required to advance a 2-inch O.D., split barrel sampler
12 inches through a soil mass.
Total Stress - At a given point in a soil mass the sum of the net stress
across contact points of soil particles (effective stress) plus the pore
water pressure at the point.
Underconsolidation - The condition that exists if a soil deposit is not
fully consolidated under the existing overburden pressure and excess
hydrostatic pore pressures exist within the material.
Varved Silt or Clay - A fine-grained glacial lake deposit with alternating
thin layers of silt or fine sand and clay, formed by variations in
sedimentation from winter to summer during the year.