关键词: 砂岩, 蠕变特性, 单轴蠕变, 振铃计数, 事件数, Weibull统计分布

Abstract: To investigate the influence of aqueous solution on the creep property of sandstone, we carried out long-term uniaxial compression creep tests on sandstone specimens of different moisture content by RLJW-2000 rock microcomputer-controlled rheology servo; and meanwhile conducted acoustic tests by SH-2 acoustic emission monitor. Test results revealed that sandstone displayed obvious strain hardening characteristics with apparent creep steady phase. At given moisture content, the creep rate of sandstone increased as stress increased; and under the same stress level, creep rate increased also as stress increased. Moreover, ring count rate and creep rate shared the same trend: the time-history curves of accumulative ring count and strain are similar in general. Assuming that the test materials obey Weibull distribution, we derived a damage evolution equation based on acoustic emission event point, and found that damage in sandstone of high moisture content developed faster than that of low moisture content under the same stress level. By comparing the critical acceleration point of creep curve and damage variable curve, we also found that acoustic emission is more accurate in predicting the time of creep.

Key words: sandstone, creep property, uniaxial creep, ring count, event count, Weibull distribution