Study On Mechanical Properties And Damage Constitutive Model Of Deep Frozen Clay

When the frozen soil is in deceleration creep,it is considered that there is no damage in the frozen soil,so the empirical equation can be used to describe the creep process in the deceleration creep stage.When the creep of frozen soil reaches a certain degree and the non attenuation creep of frozen soil occurs,the frozen soil enters the accelerated creep stage,there will be large creep deformation,damage in the frozen soil and soil damage.In this paper,the uniaxial creep tests of frozen soil under three different negative temperatures are carried out.According to the test results,the parameters in the empirical model,the variation law of frozen soil creep rate and the time required to achieve stability are analyzed.The empirical equation can better describe the deformation of frozen soil in the deceleration creep stage,but the empirical equation can not represent the acceleration creep stage.Therefore,in order to better represent the whole process of frozen soil creep,an equation with damage variable needs to be added to the empirical equation to describe the deformation of soil in the accelerated creep stage.By adding the damage evolution equation and empirical equation,a creep model which can represent the whole creep process of frozen soil is established.The creep strain of frozen soil considering damage is the sum of the first and second stage strain represented by empirical equation and the accelerated stage strain represented by damage equation.The relevant parameters in the new creep model can be obtained through simple tests,which is more convenient to determine.In the uniaxial creep test of frozen soil,the frozen soil appears accelerated failure under high stress.Through the analysis of the damage characteristics of frozen soil,the damage variable is introduced,and the constitutive equation containing damage variable which can describe the whole process of uniaxial creep of frozen soil is established.The experimental data are substituted into the constitutive equation,and the parameter values in the equation are fitted by Origin software.The established creep damage equation is compared with the actual stress-strain curve to verify the model.Finally,through the analysis of engineering cases,the creep damage model of frozen soil established in this paper is verified.The research results can provide an effective way to further study the damage and failure characteristics of artificial frozen soil,and provide effective guidance for the design and stability analysis of deep well frozen wall.Figure [34] table [14] reference [84]...