Influence of structural anisotropy on the stress relaxation behavior of anisotropic rocks = Influence of structural anisotropy on the stress relaxation behavior of anisotropic rocks

다국어 초록 (Multilingual Abstract)

Time-dependent characteristics, such as creep and stress relaxation, are among the crucial design parameters which govern the long-term stability and serviceability of underground structures located in the rock mass. However, the past studies on the time-dependent properties of rocks have commonly neglected the effect of structural anisotropy on rock located a round deep openings. A series of biaxial compression tests were performed to investigate the stress relaxation behavior of greenschist rock considering the effects of structural anisotropy and directional dependence of applied loading with foliation planes. The laboratory findings revealed that the rock specimen exhibited three distinct stages of relaxation behavior. The specimens subjected to vertical and lateral loads acting parallel to the foliation plane showed a higher stress relaxation and creep strain accumulation. Moreover, when specimens were subjected to creep along vertical direction, their lateral sides showed signs of stress relaxation, which in turn could affect the strength and stability of the surrounding rock. These results are promising and innovative which cannot be achieved using traditional creep test (uniaxial and triaxial creep test). The test results are compared with published data in the literature to understand the influence of the foliation plane on the magnitude and time to attain the maximum stress relaxation. Test findings are practically significant in view of design and stability of long deep-buried tunnels.