Loess Rheological Properties Of The Test Analysis And The Constitutive Model

The rheological property is one of important nature of soil. The distortion of clay, as well as cohesionless sand does not generate instantly, but increases with some speed. Along with the progress of West Development, more and more projects will contact with loess. The influence between loess and kinds of projects is very complicate, especially rheological property has important relation with stability and long-life performance. So the study of rheological property of Q₂ loess is carried out in the thesis.In order to analyze rheological property and establish constitutive model of Q₂ loess, a series of uniaxial creep experiments on different water content are done .The creep test curves and stress-strain isochronism curves are drawed with the result of experiments and conclusions are reached from the curves. The creep performance of Q₂ loess is different under the different stress level. In the different time the stress-strain isochronism curve has obvious inflection point namely yield stress and the yield stress reduces along with the increase of water content, which can be described by exponential function. Q₂ loess can be thought linear visco-elastic-plastic body approximately. The thesis establishes constitutive model with empirical equation law and model theory and determines related parameter. The parameters at the same water content will increase along with the increase of stress and the parameters at the same stress level will increase along with the increase of water content from empirical equation law. The parameter from model theory will reduce along with the increase of water content, which can be described by exponential function. The model also can be spread to complicated stress condition with the aid of mathematical and mechanical methods. Finally, the thesis carries on preprocess with ANSYS, namely extract information in ANSYS Parametric Design Language after establishing model. The finite element program compiled by MATLAB is used to simulate rheological law of loess. The rheological model established in the thesis has been proved correctly by comparing the result of numerical simulation with experiment. The thesis has important theoretical significance for study of rheology theory and engineering value for building projects in the loess area.