Abstract Triaxial creep characteristics of mica-quartzose schist are obtained by triaxial creep test. The polarizing microscope and scanning electron microscope are used to observe the radial and axial slices of mica-quartzose schist for three triaxial creep stages,which are no forces stage,the upcoming accelerative creep stage and the creep damage stage;and the microstructure change of mica-quartzose schist during triaxial creep process is observed. The effect of microstructure change on mica-quartzose schist is attributed to the damage variable and change in porosity. The relations of macro-stress and macro-strain with damage variable and porosity are established by statistical damage theory and simplified mechanical model,and the creep damage variable is deduced. The variation of the creep damage variable in the whole creep curve of mica-quartzose schist is analyzed;and the corresponding relationship between the creep damage variable and microstructure change of each creep stage is studied;the creep failure is interpreted from the perspective of creep damage. The creep damage variable is also simplified according to the whole creep curve in order to use conveniently.
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Received: 11 December 2009
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