Piecewise-Linear Model for Large Strain Radial Consolidation

A piecewise-linear model for radial consolidation, called RCS1, is presented. RCS1 accounts for vertical strain, soil selfweight, hydraulic conductivity anisotropy, radial and vertical flows, soil smear, partial drain penetration, unload/reload effects, time-dependent loading, and variable hydraulic conductivity and compressibility during the consolidation process. Soil constitutive relationships are specified using discrete data points and can take nearly any desired form. Soil strains are assumed to occur in the vertical direction and lateral strains are neglected. Drain hydraulic resistance is also neglected. Essentially exact agreement is observed for RCS1 uniform applied stress simulations and Barron free strain theory for problems involving very small strains. RCS1 uniform settlement simulations and Barron equal strain theory are not in exact agreement due to the approximation involved in the Barron theory. For realistic loading and soil conditions, differences are observed between RCS1 uniform applied stress and uniform settlement simulations due to differences in hydraulic conductivity and cross sectional area available for flow near the vertical drain. Estimates of settlement and excess pore pressure obtained using RCS1 are in good agreement with field measurements for a recently preloaded site over San Francisco Bay Mud with prefabricated vertical drains.