Research on Creep Characteristics of Sandstone on Dam Foundation of Xiangjiaba Hydropower Station in Jinshajiang River
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Abstract
The typical sandstone on dam foundation of Xiangjiaba hydropower station are taken samples. The creep characteristics of the sandstone are studied by triaxial compression tests. The damage characteristics of instability phase, axial strain, lateral strain and volume strain of the whole process of creep curve are analyzed, then the long-term strength of sandstone is evaluated. The results show that there is a starting stress threshold of sandstone under creepage, each creep curve has a instantaneous strain under each load which the instantaneous strain will decrease with the increase of confining stress and deviatoric stress, the axial instantaneous strain has well linear relation with the deviatoric stress. There are obvious three phases for lateral strain and volume strain, and the lateral strain and volume strain have higher growth rate than the axial strain while the creep curves are similar to each other. The lateral creep strain is higher than the axial and volume creep strain under the same confining stress or deviatoric stress. The long-term strength of sandstone can be determined by the partial stress-strain curve clusters which the volume partial stress-strain curve cluster is the best. Finally, the burgers model is most suitable model to simulate the creep characteristic of sandstone amond the current rheological constitutive models
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