Reclamation of Phosphatic Clay Waste Ponds by Capping. Volume 6. Consolidation Properties of Phosphatic Clays from Automated Slurry Consolidometer and Centrifugal Model Tests

摘要

An automated slurry consolidometer, which is fully controlled by a computer-data acquisition system that monitors load, pore pressure, total stress, and deformation, was developed. Results from the tests conducted show the effectiveness of the apparatus. The Constant Rate of Deformation test was found to have several advantages over the Controlled Hydraulic Gradient test and is recommended for future applications. The technique using centrifugal modelling is based on the measurement of pore pressure and void ratio profiles with time. The compressibility relationship obtained was in good agreement with the results of CRD tests performed at a slow rate of deformation. The permeability values, however, were approximately a half order of magnitude higher. Further research is required to explain the difference. The constitutive relationships obtained in the study were used to predict the behavior of hypothetical ponds modelled in the centrifuge. A good agreement between centrifugal and numerical models was found.