The Study Of Secondary Development Of Creep Model Of Include New Components

Soil rheological is a very broad concept,which contains several aspects such as creep,stress relaxation and long term strength,and the soil of load produces a complete creep process which contains three stages of the initial creep,stable and accelerating creep and the strain with time changing should show that a similar "s"-shaped curve.In addition,the soil which is composed of granular particles is different from solid material,and the rheology process has non-linear of wide range deformation characteristics.Because of its unique structure and properties,clay is different from a normal soil,clay stratum or sandwich brings a certain degree of difficulty to construction in engineering construction,it also brings some risks to the stability on its buildings,so it is very important to study on the physically mechanical properties and rheological properties of clay.Based on on Zhanjiang clay for triaxial not drainage creep test proceeds creep data,the paper finds that the first two stages of creep can not be accurately described when we uses the classical Burger creep model.so this paper replaces Burger creep model in the related stick pot with scores order derivative components(and said Abel component),a new creep model with one and two fractional derivatives is formed,which are named Kburger and Sburger respectively.The constitutive equations of one dimension and three dimensions are derived and compared with the classical Burger model,looking for similarities and differences points between in the three class model;then the paper built-in Burger model program file for blueprint,and uses C++ language for changing the definition of two kinds of fractional derivative model.Dynamic links library(.dll)are generated in Visual Studio 2005 above version programming platform,then with FLAC3 D for interfacing and calling,and completes the second development work and validation,the paper fits the parameters of each model based on the creep test data of Zhanjiang clay under different confining pressures of 50 Kpa constant confining pressure.The advantages and disadvantages of each model in describing the creep process of Zhanjiang clay under different deviatoric stresses are compared by comparing the numerical simulation results of triaxial creep.The paper transforms the model from a column to a cube,and discusses the influence of different shapes on the numerical simulation of three axis creep.Second,in view of the long-term deformation of the soil,the strength parameters of the soil will change with time and the soil has the characteristics of plastic deformation,the paper introduces variable strength parameter plastic element,and forms the element which is combined with the classical Burgermodel to a variable strength parameter model,and analyses the the effect of different strength parameters on the accelerated creep stage of soil.Last,A new fractional order variable strength parameter model is obtained by connecting the plastic element with the Sburger model,Combined with the hydraulic dam project in southwest county,the Cvisc model,the variable strength parameter model and the fractional order variable strength parameter model are used to predict the settlement trend after the completion,The difference between the numerical results of each model is analyzed and some suggestions are given.