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Abstract In order to investigate the creep damage property of surrounding rock of the nuclear waste disposal repository at different temperatures，temperature effects on the whole creep damage process are analyzed on the basis of the experimental results of granite specimens under uniaxial creep compression. It is shown that the temperature results in thermal damage on instantaneous elastic modulus and accelerates the subsequent creep damage process. Based on the Nishihara model，instantaneous thermal damage variable and creep damage variable considering temperature effect are presented to establish the creep damage constitutive model of granite at different temperatures. Creep test data of granite at different temperatures are used to carry out the identification of the creep damage model；and the creep parameters are obtained. It is found that the model could well describe the creep properties in whole process by comparing the results obtained from the creep damage model and the creep test data. The rationality and correctness of the creep damage model are identified. The variations in creep parameters with temperature are analyzed. The analytical results indicate that the creep damage failure time decreases rapidly with the increasing temperature；and the relationship between creep damage time and temperature satisfies negative exponent reduction law. The creep fracture property transforms from brittleness to ductility with the increasing temperature；and the creep fracture property satisfies negative exponent increase law. The relaxation time for granite decreases rapidly with the increasing temperature.
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Received: 23 March 2011
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2011, Vol. 30 
