Mechanical Properties and Damage Analysis of Cyclic Freeze-thaw Creep of Saturated Rock
In order to study the creep mechanical properties of saturated rock under cyclic freeze-thaw conditions,triaxial creep tests were carried out with different times of freeze-thaw cycles.An elastic-viscoplastic creep model was established based on the de-formation characteristics of the specimen,and the parameters of the creep model were calculated.The creep damage model of cyclic freezing-thawing process was proposed,and the damage model was verified based on the experimental data.The results show that the freeze-thaw creep process is divided into three stages:transition creep stage,stable creep stage and accelerated creep stage.Based on the elastoviscoplastic creep model,it is concluded that the creep parameters increase with the increase of loading stress,and decrease with the increase of freezing and thawing times.There are two kinds of fissures during freezing and thawing:the fissures extending along the original fissures and the fissures developing independently.The growth velocity of the original fracture is higher than that of the independently developed fracture.The growth rate of cracks increases gradually in the process of cyclic freezing-thawing.Consider-ing the effect of freezing-thawing times on creep parameters and the effect of damage coefficient on creep parameters,a creep damage model is established to explain the creep damage process of cyclic freezing-thawing,the theoretical curve of the model shows good cor-relation with the test data,which verifies the correctness of the creep damage model.
saturated cyclic freeze-thawcreep mechanical propertiescreep modelfracture development lawdamage model
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