Research on Damage Characteristics and Constitutive Model of Freeze-Thaw Fractured Rock Slopes
To study the freeze-thaw damage law of ditch slopes in cold regions,laboratory tests were conducted on N-type cracked rock samples subjected to 1,3,5,7,9,and 11 freeze-thaw cycles.Uniaxial compression tests were performed,and acoustic emission signals were recorded to analyze their strength characteristics,acoustic emission characteristics,and damage characteristics.A macro-micro coupling damage constitutive model was established and validated.The study found that after freeze-thaw cycles,the uniaxial compressive strength,damage strength,crack initiation strength,and elastic modulus of the rock samples significantly decreased,while the cumulative ringing count rate increased,and crack propagation during failure became more complex.The macroscopic damage variable was defined using classical damage theory,and the freeze-thaw damage variable was obtained by modifying the difference in open porosity.Considering the negative damage caused by the initial crack porosity compaction,a Weibull function was used for quantitative analysis of rock sample damage,establishing a micro-damage variable calculation model under load.Based on the theory of strain equivalence,the macroscopic total damage model was established,and the accuracy of the destruction framework was verified.
Freeze-thaw cycleN-fracturesuniaxial compressionacoustic emissionconstitutive model
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