关键词: 水化-冻融, 大理岩, 蠕变, 长期强度, 瞬时强度, 单轴压缩试验, 单轴压缩蠕变试验

Abstract: In order to reasonably determine the creep long-term strength σs of marble under the coupling effect of hydration freeze-thaw, uniaxial compression tests and uniaxial compression creep test were carried out with three solution environments of acid, medium and alkali and different freeze-thaw cycles as the experimental control factors in an open-pit slope in northwest Hubei Province. Then, the long-term strength of marble was compared and analyzed by combining transition creep method, isothermal stress-strain curve cluster method, steady-state creep rate stress relationship method, strength failure time relationship method, and two new methods (long-term strength prediction method based on stress-strain curve and improved steady-state creep rate stress relationship method). The results show as follows: 1) under the same number of freeze-thaw cycles, the instantaneous and long-term strength under acidic environment is the smallest, followed by alkaline environment, and the neutral environment is the largest. 2) By using transition creep method, isothermal stress-strain curve cluster method, steady-state creep rate stress relationship method, long-term strength prediction method based on stress-strain curve, and improved steady-state creep rate stress relationship method, the average long-term strength values of the marble under different solution environments and freeze-thaw cycles is 46.70, 41.21, 39.74, 43.92 and 43.67 MPa, respectively. 3) The long-term strength prediction method based on stress-strain curve does not require time-consuming creep test, and can quickly predict the long-term strength of rocks based solely on the stress-strain curve determined by compression tests. Compared with traditional methods, the improved steady-state creep rate stress relationship method eliminates the strong subjectivity of taking inflection points.

Key words: hydration freeze-thaw, marble, creep, long-term strength, instantaneous strength, uniaxial compression test, uniaxial compression creep test