中文摘要：

黏土岩具有低渗性和自我裂缝修复能力等优点,被用于高放废物地质处置的候选基岩。出于高放废物处置库的长期性及高安全性要求,研究黏土岩的蠕变破坏特征显得极其重要。通过一系列黏土岩的单级三轴压缩蠕变试验,获得Callovo-Oxfordian（COx）黏土岩较为精确的蠕变速率阈值范围。试验结果表明,发生蠕变破坏的蠕变速率阈值与黏土岩的湿度及所处围压等因素有关。总体上,当轴向蠕变速率低于2.5με/h,该类黏土岩很难发生蠕变破坏;但若高于58με/h,则黏土岩极易发生加速蠕变破坏;而处于两者之间的速率值,目前试验尚无明确结论。该阈值可用于在稳定蠕变阶段判断黏土岩是否会出现加速蠕变破坏。

英文摘要：

Clay rocks have the advantages of low permeability and crack self-sealing ability and are thus chosen as a potential geological barrier for underground disposal of radioactive waste in France and other countries. The high security and long-term requirements of underground radioactive waste disposal require that it is necessary to investigate the time-dependent behaviors of clay rocks. This paper presents the results of a series of one-step creep tests for the purpose of identifying with a relative high precision the creep rate thresholds of the Callovo-Oxfordian argillite with different moistures under the triaxial creep conditions. Three moisture levels are investigated in this paper for complete creep tests. The results show that the creep rate threshold values are related to the moisture and confining pressure. Generally, if the axial creep rate is smaller than 2.5 με/h, the tertiary creep does not occur. Otherwise, if the axial creep rate is greater than 58 με/h, the tertiary creep is likely to happen. Although the values between the two thresholds are still questionable, the thresholds are helpful to know in advance whether the tertiary creep would happen.