Abstract

During undrained shearing of saturated soils loose samples show increasing pore pressure while dense samples show decreasing pore pressure. The magnitude and sign of the pore pressure change for a given soil is determined principally by its relative density. This suggests the possibility of measuring relative density in situ by observing pore pressures generated during shearing imposed by an instrument. The most suitable instrument for this purpose is a vane fitted with a piezometer (piezovane) as a vane imposes shearing with only small changes of normal stress. A series of experiments was carried out on piezovanes in beds of fine sand prepared in the laboratory at different relative densities. The tests showed clear relationships between relative density and pore pressures measured by the piezovane. The piezovane may also be of use as an in situ test for the potential for liquefaction of loose saturated fine sand deposits.