Analysis Of Deformation And Failure Of Frozen Thawed Rock Under Load

Increasing of the numbers and scale of geotechnical engineering in cold,the prevention of freeze-thaw damage become the key problems to be solved and it is very necessary to deepen the research on deformation and failure of frozen thawed rock.In this paper,considering the rock under the coupled action of freeze-thaw cycle and load as the research object,based on the continuum damage mechanics,the influence of the freezing and thawing cycles and confining pressure on mechanical properties of rock is studied.And with the aid of numerical calculation,the compression process of rock specimens under the different freeze-thaw cycles and different confining pressure conditions were analyzed.Based on the theory of damage mechanics,using the strain equivalent principle after the promotion,respectively setting up damage evolution equation and damage constitutive relation of rocks under action of single load and freeze-thaw under the coupled load and using the test data of rock under the conditions of normal temperature and the triaxial compression after the cold to verify constitutive model,the rationality of the model is proved.When the confining pressure is constant,with the increase of number of freezing and thawing,the total damage variable is increasing gradually,and the strength of the rock is decreasing.The freeze-thaw cycle weakening the rock brittleness,enhancing its plasticity;When the freeze-thaw cycles is unchanged,the total damage variable decreases with the increase of confining pressure,the plastic properties is increasing obviously,and the strength of the rock is decreasing.By means of the method of finite element numerical calculation,and using the sequential coupling thought in thermal analysis,simulating of the rock sample after freeze-thaw cycling test and compression experiment after freeze-thaw under the condition of different confining pressure.By comparing the numerical simulation with the experimental results,the feasibility of the numerical method to simulate the deformation and destruction of the frozen rock is simulated.An idea is provided for the analysis of damage characteristics of frozen rocks.