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Mathematical Problems in Engineering
Volume 2014, Article ID 804586, 8 pages
Research Article

Uniform Nonlinear Constitutive Model and Parameters for Clay in Different Consolidation Conditions Based on Regression Method

1School of Civil Engineering, Hubei Polytechnic University, Huangshi 435003, China
2School of Chemical and Material Engineering, Hubei Polytechnic University, Huangshi 435003, China

Received 19 December 2013; Accepted 3 April 2014; Published 6 April 2014

Academic Editor: Fei Kang

Copyright © 2014 Tao Cheng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The nonlinear constitutive relations of clay are investigated considering different initial conditions. Highly compressible clay is selected as the test sample. Two groups of tri-axial compression tests are performed, respectively, after consolidation and isotropic consolidation. On the basis of the framework of model, a uniform nonlinear constitutive model is proposed by fitting the test data. With the average slope of the unloading-reloading curve selected as the unloading modulus, the unloading function is constructed as the loading-unloading criterion. Moreover, a comparison between the experimental stress-strain curves and the results predicted by the constitutive model is made. It is shown that the prediction is reasonable, which can reflect the stress-strain behavior of the soil under the consolidation and isotropic consolidation conditions. The maximum relative error of the two series of curves is not remarkable, less than 6%.