Study Of Laboratory Prepared Frozen Soil Property And Fractional Order Derivative Nishihara Model

In recent years, with the rapidly development of industry and agriculture in cold area,The freezing method is widely used in coal mine freezing method sinking, the sea tunnel, subway,other projects and so on,various konds problems happended in engineering construction process, such as:pervious to water in the coal mine, the tunnel collapse,the tunnel waterproof pervious to water and so on,These problems caused the production downtime, interruption of train driving, huge economic loss and other issues, has brought the huge impact with the society. People are increasingly recognized that the problem of frozen soil are urgent.Therefore, permafrost has become an important research topic of study; This article is based on the elastic-plastic constitutive model of frozen soil and the particle swarm fractional order derivative Nishihara is studied.The article research results has important guiding significance on theory and practical engineering problemsThe frozen sandy clay mechanics trials were carried out by frozen W3Z-200type electro-hydraulic servo triaxial trial machine developed by the Atifical Frozen Soil Mechanic Study institute,Anhui University of Science and Technology;Undisturbed and remolded soil was triaxial shear tested with the different temperature (-5℃,-10℃,-15℃) and different confining pressure (1MPa,2MPa,3MPa),the stress-strain curve and triaxial shear strength were getted, the strength of the remolded soil is lower than the strength of the undisturbed soil can be found by comparison. Undisturbed soil type is strain soften,remolded soil type belongs to the strong strain harden. The permafrost yield function of modified cam-clay model was established based on permafrost yield criterion and associated flow rule, the elastic-plastic constitutive model of frozen soil was established, in order to verify the rationality of the constitutive model, this model is solved on the format of the program with implicit function integrals, the rationality of the constitutive model was verified.The uniaxial testing machine for the creep mechanics test of frozen sandy clay were carried out by frozen WDT-100type microcomputer control electro-hydraulic servo machine developed by the Atifical Frozen Soil Mechanic Study institute,Anhui University of Science and Technology; The uniaxial strength under uniaxial creep test were implemented under the three temperature (-5℃,-10℃,-15℃) and three load coefficient (0.3σs、0.5s、0.7σ), the stress-strain curve. was obtained.Based on the traditional Nishihara model cannot describe the deformation of frozen soil creep expedite stage, Based on the properties of the fractional order derivative and of the fractional order derivative Nishihara model was established, the classic Nishihara and the fractional order derivative fitting method for the numerical model, in the Nishihara model of the fractional order derivative is proposed to fit with method of particle swarm optimization, particle swarm of fractional order derivative is verified the Nishihara model in fitting the superiority in the process of expedite rheological.