Analytical model for consolidation settlements under centrifuge environment

Abstract

Accurate estimation of consolidation settlements is of great engineering interest to address the problem of ground subsidence. Centrifuge consolidation testing in the laboratory is gaining importance due to the requirement of shorter testing time in predicting consolidation settlement. An analytical model is presented for estimating the rate of consolidation settlements using a one-dimensional large-strain consolidation framework in a centrifuge environment. The model accounts for soil self-weight, relative velocity of the fluid and solid phases, different soil compressibility and hydraulic conductivities, and variation of acceleration factor along the specimen length. Development of the proposed model is first presented and is followed by a numerical solution of the model for different drainage boundary conditions using the finite-difference approach. A comparison of the proposed model with the currently available piecewise-linear model, CC1, on Singapore marine clay data shows that the proposed model uses very large time steps in the time marching process after satisfying the stability and convergence criteria. The proposed model is computationally superior to the existing fully numerical approach. Numerical simulations with different centrifuge parameters show that the approximation of the constant acceleration factor over the sample depth overestimates the settlements nearly 45% for a chosen initial specimen height and at a given centrifuge time. The proposed model is capable of simulating consolidation settlements of different clays whose constitutive parameters vary widely.