Strength Characteristics Analysis And Explicit Creep Constitutive Model Of Deep Clay Under Temperature Effect

Artificial freezing method has become the most commonly used method in deep well construction,mine excavation,metro tunnel and other projects because it is not limited by the depth and scope of support.The strength and deformation of frozen wall is the key to the success of freezing construction.In order to ensure the safety of underground construction,the mechanical characteristics of frozen soil should be carefully explored.Taking a mine clay in Shanxi Province as the research object,this paper explores the change law of strength and damage deformation characteristics of frozen clay by means of Laboratory mechanical test,constitutive model deduction and three-dimensional FLAC numerical simulation.Firstly,the uniaxial compressive strength of frozen clay at different temperatures and the creep law of frozen clay at different temperatures and loading levels are obtained through laboratory mechanical tests.The stress-strain curves and strain-time curves were further analyzed,and the relationship between temperature,elastic modulus and creep rate was obtained Based on the Singh-Mitchell creep empirical model,an explicit S-M creep model describing the creep behavior of frozen clay is derived by modifying the physical meaning of the parameters in the original model and considering the effect of temperature on the creep behavior of frozen clay.By analyzing the contrast curve between S-M explicit creep model and test value,it is found that the test value of frozen clay strain is not in good agreement with S-M explicit creep model when the stress level is high.Therefore,a creep damage model of frozen clay S-M is obtained by introducing damage variable into the S-M creep explicit model.According to the uniaxial creep test data of frozen clay,the parameters of S-M creep damage model are optimized and identified The S-M creep damage model can simulate the whole creep process of frozen clay.In order to reduce the error of the test results,the uniaxial compressive strength test of the frozen remolded clay is carried out again in this paper.The influence of temperature and water content on the uniaxial strength,elastic modulus and Poisson's ratio of the frozen remolded clay is analyzed The uniaxial compression process of frozen remolded clay is simulated by FLAC three-dimensional software according to the test results.It is found that the simulation results are basically consistent with the test data.This is of great significance to the establishment of the prediction model of frozen soil compression deformation in practical engineering.Figure[47]Table[9]Reference[85]...