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Creep is a common phenomenon for soft clays. e paper focuses on investigating the influence of temperature on the timedependent stress-strain evolution. For this purpose, the temperature-dependent creep behavior for the soft clay has been investigated based on experimental observations. A thermally related equation is proposed to bridge the thermal creep coefficient with temperature. By incorporating the equation to a selected one-dimensional (1D) elastic viscoplastic (EVP) model, a thermal creep-based EVP model was developed which takes into account the influence of temperature on creep. Simulations of oedometer tests on reconstituted clay are made through coupled consolidation analysis. e bonding effect of the soil structure on compressive behavior for intact clay is studied. By incorporating the influence of the soil structure, the thermal creep EVP model is extended for intact clay. Experimental predictions for thermal creep oedometer tests are simulated at different temperatures and compared to that obtained from reconstituted clay. e results show that the influence of temperature on the creep behavior for intact clay is significant, and the model, this paper proposed, can successfully reproduce the thermal creep behavior of the soft clay under the 1D loading condition.

Conventional consolidation tests on reconstituted specimens of numerous natural soft clays show a decreasing of creep index C e with increasing soil density. Based on all selected and conducted experimental results, a modified creep index C e * defined in double logarithmic plane lge-lgt, was plotted for various clays, from which C e * can be assumed as a constant for different soil densities. Then, the modified creep index was applied to a newly developed elastic viscoplastic model. In this way, the modified creep index C e * can naturally take into account the nonlinear C e revealing the influence of soil density in the soil assemblies without additional parameters. Finally, the enhanced model was incorporated into the finite element code ABAQUS and used to simulate a consolidation test and a test embankment. The improvement of simulations by the modified creep index was highlighted by comparing simulations using the conventional creep index C e .

Abstract:The parameters obtained from oedometric consolidation tests are commonly used in the development of constitutive modeling and for engineering practice. This paper focuses on the influence of the natural deposition plane orientation on oedometric consolidation behavior of three natural clays from the southeast coast of China. Oedometer tests were conducted on intact specimens prepared by sampling at a series of angles relative to the natural deposition plane. For each specimen, yield stress, compressibility indexes, secondary compression, and permeability coefficients were determined. The influence of the sampling angle on these properties was investigated, revealing that yield stress, compression index, swelling index, creep index, ratio of secondary compression coefficient to compression index (C e /C c ) and permeability coefficient were all dependent to some extent on the sampling angle. These findings indicate the role of the anisotropy due to the natural deposition on the oedometric consolidation behavior.