Prediction of hydraulic conductivity parameters of slurries from centrifuge consolidation settlements

Abstract

Slurry materials such as mine tailings and dredged clays undergo large, self-weight consolidation settlements. Compressibility and hydraulic conductivity characteristics of such slurries are essential for the estimation of their settlements and settlement rates for the safe maintenance of the storage facilities. These two constitutive functions of slurry materials are frequently estimated from laborious large-strain consolidation tests. Centrifuge consolidations tests are receiving great attention, therefore, to circumvent the time-consuming consolidation tests in the 1 g environment. However, the inverse analysis of settlement–time data for the estimation of compressibility and hydraulic conductivity functions is computationally expensive due to the requirement of a large number of forward analyses and thus is not available yet for the centrifuge environment. In this work, for the first time, two existing back analysis procedures for 1 g column tests were explored for predicting the hydraulic conductivity parameters of several slurry materials from the centrifuge test data. These procedures require well-defined and time-invariant compressibility functions of the slurry materials. These methods need only time–settlement data from a single centrifuge test, and do not depend on the excess pore pressure profiles. A finite difference solution of the analytical model for finite strain consolidation behavior of samples in centrifuge environment was utilized for the forward analysis. Four simulated synthetic temporal settlement curves and four centrifuge consolidation test data from the literature were utilized for validation of the studied methods. The methods were simple, computationally inexpensive due to the requirement of only a smaller number of forward analyses, and effective in accurately predicting the hydraulic conductivity constitutive parameters.