摘要
基于向家坝砂岩的常规三轴压缩试验和三轴压缩流变试验成果,分别通过应变等时曲线簇、稳态蠕变速率与应力水平的关系、裂纹损伤应力、流变荷载与破坏时间关系确定砂岩的长期强度,并比较这4种方法的适用性。结果表明:砂岩体积应变等时曲线簇的拐点比轴向应变、侧向应变等时曲线的拐点更为明显,而且其对应力水平和时间的反应更敏感;轴向稳态蠕变速率和侧向稳态蠕变速率与应力的关系符合指数函数关系,采用给定稳态蠕变速率阈值确定岩石长期强度比利用稳态蠕变速率-应力曲线的拐点确定长期强度更为合理;岩石的裂纹体积应变等时曲线簇以及其稳态蠕变速率与应力的关系也可以作为确定岩石长期强度的一种方法;岩石的裂纹损伤应力反映长期强度所在应力水平,为蠕变试验荷载分级提供依据。
Conventional triaxial compression tests and triaxial compression creep tests were carried out on Xiangjiaba sandstone, and the long-term strength of Xiangjiaba sandstone was estimated. To do that, a series of observations were used including isotime curves of strain, relations between steady creep rate and applied stress, relations between applied stress and time to failure, and crack damage stress. Isotime curves of volumetric strain are more sensitive to time and applied stress than isotime curves of axial and lateral strain. The volumetric strain isotime curves have the most obvious turning points, which are considered to be indicators of long-term strength. Relation between axial （lateral） steady-state creep rate and the deviatoric stress can be described by an exponential function. Steady-state creep rate threshold was proposed to determine long-term strength of rock. This method is more reasonable than that using the turning point of steady-state creep rate-stress curve. The long-term strength of rock can also be estimated by isotime curves of crack volumetric strain and the relation between steady-state crackvolumetric strain rate and the deviatoric stress. It is found that crack damage stress can indicate the level of long-term strength of rock, which provides the basis for determining applied stress in multi-stepped creep test.
出处
《工程力学》
EI
CSCD
北大核心
2010年第11期127-136,143,共11页
Engineering Mechanics
基金
国家自然科学基金项目(50979030
50911130366)
国家科技支撑计划项目(2008BAB29B01)
作者简介
李良权（1981-），男，湖北荆州人，博士生，从事岩石力学与工程研究（E—mail：liliangquan1024@sina．com）
徐卫亚（1962-），男，江苏张家港人，教授，博士，博导，从事岩石力学与工程研究（E—mail：wyxu@hhu．edu．cn）；
王伟（1978--），男，安徽合肥人，讲师，博士，从事岩石力学与工程研究（E—mail：wwang@hhu．edu.cn）；
郭云强（1969--），男，湖南长沙人，高工、学士，从事水电站地下工程设计与研究（E-mail：GYQMSDI@163．com）；
赵海斌（1965-），男，湖南衡山人，教授级高工，博士，从事岩土工程设计与研究（E—mail：hbzhao@139．com）．
