Interpretation of horizontal permeability from piezocone dissipation tests in soft clays

Piezocone is a common site investigation tool where a cone penetrometer is pushed into ground. In fine-grained soils, the penetrometer can be stopped to measure pore pressure decay, known as dissipation testing. Conventionally the horizontal coefficient of consolidation has to be first determined before the hydraulic conductivity can be estimated. This study uses the modified Cam-clay soil model to numerically simulate dissipation tests. A total of 90 calculations are performed to derive a new dimensionless time factor that easily and directly evaluates horizontal permeability for both standard and non-standard dissipation curves. The proposed equation is validated with field data.