Genetic Fractional Order Derivative Of Artificial Frozen Soil Creep Constitutive Model Research

Frozen soil is a kind of extremely complicated engineering application material, its special composition and complex structure determines the frozen soil have complex engineering characteristics. In the traditional study of soil mechanics,the constitutive relation of soil is the relationship between stress and strain. But in fact, the stress and strain relationship of nature soil has closely relationship with time. More and more engineering examples show that the destruction of many geotechnical engineering is related to rheological permafrost. Therefore, the research of the rheological properties of frozen soil has important theoretical value and practical significance. As the importance of the soil’s constitutive relation in soil mechanics, the rheological constitutive relation of soil is the key of the soil’s rheology research.Based on the basic definition of fractional derivative,,this paper has constructed a new rheological element Abel dashpot, and combined with other classic components, has been describing the frozen soil creep model of the rheological properties, the new idea that replacing the traditional Newton dashpot with Abel dashpat is proposed here. The frozen soil materials especially creep performance are analyzed by Using both theories of fractional order derivative and classical viscoelasticity. On the basis of kelvin model, using the corresponding relation of parameters in the artificial frozen soil creep equation to establish the nonlinear creep model of parameters, according to shortage that Integer order calculus constitutive relationship need more components ect, using fractional order calculus to describe the process of artificial frozen soil creep. To collect the clay in the area of huainan and huaibei, then do the frozen soil’s uniaxial compressive strength test and uniaxial creep test in the self-developed WDT-100frozen soil performance experiment machine,using both the classic Kelvin model and the fractional order derivative Kelvin model to build model with the test results, and using the genetic algorithm for doing global optimization. The research shows that:Fractional derivative model can accurately fitting of the frozen soil’s creep process, and it’s form is simple and unified, and it need to adjust very few parameters in the calculation process,often much accurate than the classical Maxwell model,the classic Kelvin model, the classic three components of solid model, the classic Burgers model, the classic xiyuan model. Fractional derivative model unifies the methods of fractional calculus model theory and classical model theory,and makes the physic conception of the model more clear.and makes the existing scattered individual works of fractional calculus models systemic and makes the method of solution systemic.lt overcomes the serious shortcoming of the classical model theory that the results cannot fit the experimental dada very well.Excellent results can be obtained by using the combination of a few numbers of elements of the model. It is predictable that fractional model will have wide applications in the field of rheological constitution of soil,structural vibration control,high polymers materials and their calculation...